e5430d56da79f56eacb55226c69778563dbc5355
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "config.h"
   6#include "tempfile.h"
   7#include "quote.h"
   8#include "diff.h"
   9#include "diffcore.h"
  10#include "delta.h"
  11#include "xdiff-interface.h"
  12#include "color.h"
  13#include "attr.h"
  14#include "run-command.h"
  15#include "utf8.h"
  16#include "userdiff.h"
  17#include "submodule-config.h"
  18#include "submodule.h"
  19#include "ll-merge.h"
  20#include "string-list.h"
  21#include "argv-array.h"
  22#include "graph.h"
  23
  24#ifdef NO_FAST_WORKING_DIRECTORY
  25#define FAST_WORKING_DIRECTORY 0
  26#else
  27#define FAST_WORKING_DIRECTORY 1
  28#endif
  29
  30static int diff_detect_rename_default;
  31static int diff_indent_heuristic = 1;
  32static int diff_rename_limit_default = 400;
  33static int diff_suppress_blank_empty;
  34static int diff_use_color_default = -1;
  35static int diff_context_default = 3;
  36static int diff_interhunk_context_default;
  37static const char *diff_word_regex_cfg;
  38static const char *external_diff_cmd_cfg;
  39static const char *diff_order_file_cfg;
  40int diff_auto_refresh_index = 1;
  41static int diff_mnemonic_prefix;
  42static int diff_no_prefix;
  43static int diff_stat_graph_width;
  44static int diff_dirstat_permille_default = 30;
  45static struct diff_options default_diff_options;
  46static long diff_algorithm;
  47static unsigned ws_error_highlight_default = WSEH_NEW;
  48
  49static char diff_colors[][COLOR_MAXLEN] = {
  50        GIT_COLOR_RESET,
  51        GIT_COLOR_NORMAL,       /* CONTEXT */
  52        GIT_COLOR_BOLD,         /* METAINFO */
  53        GIT_COLOR_CYAN,         /* FRAGINFO */
  54        GIT_COLOR_RED,          /* OLD */
  55        GIT_COLOR_GREEN,        /* NEW */
  56        GIT_COLOR_YELLOW,       /* COMMIT */
  57        GIT_COLOR_BG_RED,       /* WHITESPACE */
  58        GIT_COLOR_NORMAL,       /* FUNCINFO */
  59};
  60
  61static NORETURN void die_want_option(const char *option_name)
  62{
  63        die(_("option '%s' requires a value"), option_name);
  64}
  65
  66static int parse_diff_color_slot(const char *var)
  67{
  68        if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  69                return DIFF_CONTEXT;
  70        if (!strcasecmp(var, "meta"))
  71                return DIFF_METAINFO;
  72        if (!strcasecmp(var, "frag"))
  73                return DIFF_FRAGINFO;
  74        if (!strcasecmp(var, "old"))
  75                return DIFF_FILE_OLD;
  76        if (!strcasecmp(var, "new"))
  77                return DIFF_FILE_NEW;
  78        if (!strcasecmp(var, "commit"))
  79                return DIFF_COMMIT;
  80        if (!strcasecmp(var, "whitespace"))
  81                return DIFF_WHITESPACE;
  82        if (!strcasecmp(var, "func"))
  83                return DIFF_FUNCINFO;
  84        return -1;
  85}
  86
  87static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  88                                struct strbuf *errmsg)
  89{
  90        char *params_copy = xstrdup(params_string);
  91        struct string_list params = STRING_LIST_INIT_NODUP;
  92        int ret = 0;
  93        int i;
  94
  95        if (*params_copy)
  96                string_list_split_in_place(&params, params_copy, ',', -1);
  97        for (i = 0; i < params.nr; i++) {
  98                const char *p = params.items[i].string;
  99                if (!strcmp(p, "changes")) {
 100                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 101                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 102                } else if (!strcmp(p, "lines")) {
 103                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
 104                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 105                } else if (!strcmp(p, "files")) {
 106                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 107                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
 108                } else if (!strcmp(p, "noncumulative")) {
 109                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 110                } else if (!strcmp(p, "cumulative")) {
 111                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 112                } else if (isdigit(*p)) {
 113                        char *end;
 114                        int permille = strtoul(p, &end, 10) * 10;
 115                        if (*end == '.' && isdigit(*++end)) {
 116                                /* only use first digit */
 117                                permille += *end - '0';
 118                                /* .. and ignore any further digits */
 119                                while (isdigit(*++end))
 120                                        ; /* nothing */
 121                        }
 122                        if (!*end)
 123                                options->dirstat_permille = permille;
 124                        else {
 125                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 126                                            p);
 127                                ret++;
 128                        }
 129                } else {
 130                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 131                        ret++;
 132                }
 133
 134        }
 135        string_list_clear(&params, 0);
 136        free(params_copy);
 137        return ret;
 138}
 139
 140static int parse_submodule_params(struct diff_options *options, const char *value)
 141{
 142        if (!strcmp(value, "log"))
 143                options->submodule_format = DIFF_SUBMODULE_LOG;
 144        else if (!strcmp(value, "short"))
 145                options->submodule_format = DIFF_SUBMODULE_SHORT;
 146        else if (!strcmp(value, "diff"))
 147                options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 148        else
 149                return -1;
 150        return 0;
 151}
 152
 153static int git_config_rename(const char *var, const char *value)
 154{
 155        if (!value)
 156                return DIFF_DETECT_RENAME;
 157        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 158                return  DIFF_DETECT_COPY;
 159        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 160}
 161
 162long parse_algorithm_value(const char *value)
 163{
 164        if (!value)
 165                return -1;
 166        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 167                return 0;
 168        else if (!strcasecmp(value, "minimal"))
 169                return XDF_NEED_MINIMAL;
 170        else if (!strcasecmp(value, "patience"))
 171                return XDF_PATIENCE_DIFF;
 172        else if (!strcasecmp(value, "histogram"))
 173                return XDF_HISTOGRAM_DIFF;
 174        return -1;
 175}
 176
 177static int parse_one_token(const char **arg, const char *token)
 178{
 179        const char *rest;
 180        if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 181                *arg = rest;
 182                return 1;
 183        }
 184        return 0;
 185}
 186
 187static int parse_ws_error_highlight(const char *arg)
 188{
 189        const char *orig_arg = arg;
 190        unsigned val = 0;
 191
 192        while (*arg) {
 193                if (parse_one_token(&arg, "none"))
 194                        val = 0;
 195                else if (parse_one_token(&arg, "default"))
 196                        val = WSEH_NEW;
 197                else if (parse_one_token(&arg, "all"))
 198                        val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 199                else if (parse_one_token(&arg, "new"))
 200                        val |= WSEH_NEW;
 201                else if (parse_one_token(&arg, "old"))
 202                        val |= WSEH_OLD;
 203                else if (parse_one_token(&arg, "context"))
 204                        val |= WSEH_CONTEXT;
 205                else {
 206                        return -1 - (int)(arg - orig_arg);
 207                }
 208                if (*arg)
 209                        arg++;
 210        }
 211        return val;
 212}
 213
 214/*
 215 * These are to give UI layer defaults.
 216 * The core-level commands such as git-diff-files should
 217 * never be affected by the setting of diff.renames
 218 * the user happens to have in the configuration file.
 219 */
 220void init_diff_ui_defaults(void)
 221{
 222        diff_detect_rename_default = 1;
 223}
 224
 225int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 226{
 227        if (!strcmp(var, "diff.indentheuristic"))
 228                diff_indent_heuristic = git_config_bool(var, value);
 229        return 0;
 230}
 231
 232int git_diff_ui_config(const char *var, const char *value, void *cb)
 233{
 234        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 235                diff_use_color_default = git_config_colorbool(var, value);
 236                return 0;
 237        }
 238        if (!strcmp(var, "diff.context")) {
 239                diff_context_default = git_config_int(var, value);
 240                if (diff_context_default < 0)
 241                        return -1;
 242                return 0;
 243        }
 244        if (!strcmp(var, "diff.interhunkcontext")) {
 245                diff_interhunk_context_default = git_config_int(var, value);
 246                if (diff_interhunk_context_default < 0)
 247                        return -1;
 248                return 0;
 249        }
 250        if (!strcmp(var, "diff.renames")) {
 251                diff_detect_rename_default = git_config_rename(var, value);
 252                return 0;
 253        }
 254        if (!strcmp(var, "diff.autorefreshindex")) {
 255                diff_auto_refresh_index = git_config_bool(var, value);
 256                return 0;
 257        }
 258        if (!strcmp(var, "diff.mnemonicprefix")) {
 259                diff_mnemonic_prefix = git_config_bool(var, value);
 260                return 0;
 261        }
 262        if (!strcmp(var, "diff.noprefix")) {
 263                diff_no_prefix = git_config_bool(var, value);
 264                return 0;
 265        }
 266        if (!strcmp(var, "diff.statgraphwidth")) {
 267                diff_stat_graph_width = git_config_int(var, value);
 268                return 0;
 269        }
 270        if (!strcmp(var, "diff.external"))
 271                return git_config_string(&external_diff_cmd_cfg, var, value);
 272        if (!strcmp(var, "diff.wordregex"))
 273                return git_config_string(&diff_word_regex_cfg, var, value);
 274        if (!strcmp(var, "diff.orderfile"))
 275                return git_config_pathname(&diff_order_file_cfg, var, value);
 276
 277        if (!strcmp(var, "diff.ignoresubmodules"))
 278                handle_ignore_submodules_arg(&default_diff_options, value);
 279
 280        if (!strcmp(var, "diff.submodule")) {
 281                if (parse_submodule_params(&default_diff_options, value))
 282                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 283                                value);
 284                return 0;
 285        }
 286
 287        if (!strcmp(var, "diff.algorithm")) {
 288                diff_algorithm = parse_algorithm_value(value);
 289                if (diff_algorithm < 0)
 290                        return -1;
 291                return 0;
 292        }
 293
 294        if (!strcmp(var, "diff.wserrorhighlight")) {
 295                int val = parse_ws_error_highlight(value);
 296                if (val < 0)
 297                        return -1;
 298                ws_error_highlight_default = val;
 299                return 0;
 300        }
 301
 302        if (git_color_config(var, value, cb) < 0)
 303                return -1;
 304
 305        return git_diff_basic_config(var, value, cb);
 306}
 307
 308int git_diff_basic_config(const char *var, const char *value, void *cb)
 309{
 310        const char *name;
 311
 312        if (!strcmp(var, "diff.renamelimit")) {
 313                diff_rename_limit_default = git_config_int(var, value);
 314                return 0;
 315        }
 316
 317        if (userdiff_config(var, value) < 0)
 318                return -1;
 319
 320        if (skip_prefix(var, "diff.color.", &name) ||
 321            skip_prefix(var, "color.diff.", &name)) {
 322                int slot = parse_diff_color_slot(name);
 323                if (slot < 0)
 324                        return 0;
 325                if (!value)
 326                        return config_error_nonbool(var);
 327                return color_parse(value, diff_colors[slot]);
 328        }
 329
 330        /* like GNU diff's --suppress-blank-empty option  */
 331        if (!strcmp(var, "diff.suppressblankempty") ||
 332                        /* for backwards compatibility */
 333                        !strcmp(var, "diff.suppress-blank-empty")) {
 334                diff_suppress_blank_empty = git_config_bool(var, value);
 335                return 0;
 336        }
 337
 338        if (!strcmp(var, "diff.dirstat")) {
 339                struct strbuf errmsg = STRBUF_INIT;
 340                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 341                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 342                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 343                                errmsg.buf);
 344                strbuf_release(&errmsg);
 345                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 346                return 0;
 347        }
 348
 349        if (starts_with(var, "submodule."))
 350                return parse_submodule_config_option(var, value);
 351
 352        if (git_diff_heuristic_config(var, value, cb) < 0)
 353                return -1;
 354
 355        return git_default_config(var, value, cb);
 356}
 357
 358static char *quote_two(const char *one, const char *two)
 359{
 360        int need_one = quote_c_style(one, NULL, NULL, 1);
 361        int need_two = quote_c_style(two, NULL, NULL, 1);
 362        struct strbuf res = STRBUF_INIT;
 363
 364        if (need_one + need_two) {
 365                strbuf_addch(&res, '"');
 366                quote_c_style(one, &res, NULL, 1);
 367                quote_c_style(two, &res, NULL, 1);
 368                strbuf_addch(&res, '"');
 369        } else {
 370                strbuf_addstr(&res, one);
 371                strbuf_addstr(&res, two);
 372        }
 373        return strbuf_detach(&res, NULL);
 374}
 375
 376static const char *external_diff(void)
 377{
 378        static const char *external_diff_cmd = NULL;
 379        static int done_preparing = 0;
 380
 381        if (done_preparing)
 382                return external_diff_cmd;
 383        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 384        if (!external_diff_cmd)
 385                external_diff_cmd = external_diff_cmd_cfg;
 386        done_preparing = 1;
 387        return external_diff_cmd;
 388}
 389
 390/*
 391 * Keep track of files used for diffing. Sometimes such an entry
 392 * refers to a temporary file, sometimes to an existing file, and
 393 * sometimes to "/dev/null".
 394 */
 395static struct diff_tempfile {
 396        /*
 397         * filename external diff should read from, or NULL if this
 398         * entry is currently not in use:
 399         */
 400        const char *name;
 401
 402        char hex[GIT_MAX_HEXSZ + 1];
 403        char mode[10];
 404
 405        /*
 406         * If this diff_tempfile instance refers to a temporary file,
 407         * this tempfile object is used to manage its lifetime.
 408         */
 409        struct tempfile tempfile;
 410} diff_temp[2];
 411
 412typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 413
 414struct emit_callback {
 415        int color_diff;
 416        unsigned ws_rule;
 417        int blank_at_eof_in_preimage;
 418        int blank_at_eof_in_postimage;
 419        int lno_in_preimage;
 420        int lno_in_postimage;
 421        sane_truncate_fn truncate;
 422        const char **label_path;
 423        struct diff_words_data *diff_words;
 424        struct diff_options *opt;
 425        struct strbuf *header;
 426};
 427
 428static int count_lines(const char *data, int size)
 429{
 430        int count, ch, completely_empty = 1, nl_just_seen = 0;
 431        count = 0;
 432        while (0 < size--) {
 433                ch = *data++;
 434                if (ch == '\n') {
 435                        count++;
 436                        nl_just_seen = 1;
 437                        completely_empty = 0;
 438                }
 439                else {
 440                        nl_just_seen = 0;
 441                        completely_empty = 0;
 442                }
 443        }
 444        if (completely_empty)
 445                return 0;
 446        if (!nl_just_seen)
 447                count++; /* no trailing newline */
 448        return count;
 449}
 450
 451static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 452{
 453        if (!DIFF_FILE_VALID(one)) {
 454                mf->ptr = (char *)""; /* does not matter */
 455                mf->size = 0;
 456                return 0;
 457        }
 458        else if (diff_populate_filespec(one, 0))
 459                return -1;
 460
 461        mf->ptr = one->data;
 462        mf->size = one->size;
 463        return 0;
 464}
 465
 466/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 467static unsigned long diff_filespec_size(struct diff_filespec *one)
 468{
 469        if (!DIFF_FILE_VALID(one))
 470                return 0;
 471        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 472        return one->size;
 473}
 474
 475static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 476{
 477        char *ptr = mf->ptr;
 478        long size = mf->size;
 479        int cnt = 0;
 480
 481        if (!size)
 482                return cnt;
 483        ptr += size - 1; /* pointing at the very end */
 484        if (*ptr != '\n')
 485                ; /* incomplete line */
 486        else
 487                ptr--; /* skip the last LF */
 488        while (mf->ptr < ptr) {
 489                char *prev_eol;
 490                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 491                        if (*prev_eol == '\n')
 492                                break;
 493                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 494                        break;
 495                cnt++;
 496                ptr = prev_eol - 1;
 497        }
 498        return cnt;
 499}
 500
 501static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 502                               struct emit_callback *ecbdata)
 503{
 504        int l1, l2, at;
 505        unsigned ws_rule = ecbdata->ws_rule;
 506        l1 = count_trailing_blank(mf1, ws_rule);
 507        l2 = count_trailing_blank(mf2, ws_rule);
 508        if (l2 <= l1) {
 509                ecbdata->blank_at_eof_in_preimage = 0;
 510                ecbdata->blank_at_eof_in_postimage = 0;
 511                return;
 512        }
 513        at = count_lines(mf1->ptr, mf1->size);
 514        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 515
 516        at = count_lines(mf2->ptr, mf2->size);
 517        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 518}
 519
 520static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 521                        int first, const char *line, int len)
 522{
 523        int has_trailing_newline, has_trailing_carriage_return;
 524        int nofirst;
 525        FILE *file = o->file;
 526
 527        fputs(diff_line_prefix(o), file);
 528
 529        if (len == 0) {
 530                has_trailing_newline = (first == '\n');
 531                has_trailing_carriage_return = (!has_trailing_newline &&
 532                                                (first == '\r'));
 533                nofirst = has_trailing_newline || has_trailing_carriage_return;
 534        } else {
 535                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 536                if (has_trailing_newline)
 537                        len--;
 538                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 539                if (has_trailing_carriage_return)
 540                        len--;
 541                nofirst = 0;
 542        }
 543
 544        if (len || !nofirst) {
 545                fputs(set, file);
 546                if (!nofirst)
 547                        fputc(first, file);
 548                fwrite(line, len, 1, file);
 549                fputs(reset, file);
 550        }
 551        if (has_trailing_carriage_return)
 552                fputc('\r', file);
 553        if (has_trailing_newline)
 554                fputc('\n', file);
 555}
 556
 557static void emit_line(struct diff_options *o, const char *set, const char *reset,
 558                      const char *line, int len)
 559{
 560        emit_line_0(o, set, reset, line[0], line+1, len-1);
 561}
 562
 563enum diff_symbol {
 564        DIFF_SYMBOL_CONTEXT,
 565        DIFF_SYMBOL_PLUS,
 566        DIFF_SYMBOL_MINUS,
 567        DIFF_SYMBOL_NO_LF_EOF,
 568        DIFF_SYMBOL_CONTEXT_FRAGINFO,
 569        DIFF_SYMBOL_CONTEXT_MARKER,
 570        DIFF_SYMBOL_SEPARATOR
 571};
 572/*
 573 * Flags for content lines:
 574 * 0..12 are whitespace rules
 575 * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 576 * 16 is marking if the line is blank at EOF
 577 */
 578#define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF (1<<16)
 579#define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 580
 581static void emit_line_ws_markup(struct diff_options *o,
 582                                const char *set, const char *reset,
 583                                const char *line, int len, char sign,
 584                                unsigned ws_rule, int blank_at_eof)
 585{
 586        const char *ws = NULL;
 587
 588        if (o->ws_error_highlight & ws_rule) {
 589                ws = diff_get_color_opt(o, DIFF_WHITESPACE);
 590                if (!*ws)
 591                        ws = NULL;
 592        }
 593
 594        if (!ws)
 595                emit_line_0(o, set, reset, sign, line, len);
 596        else if (blank_at_eof)
 597                /* Blank line at EOF - paint '+' as well */
 598                emit_line_0(o, ws, reset, sign, line, len);
 599        else {
 600                /* Emit just the prefix, then the rest. */
 601                emit_line_0(o, set, reset, sign, "", 0);
 602                ws_check_emit(line, len, ws_rule,
 603                              o->file, set, reset, ws);
 604        }
 605}
 606
 607static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
 608                             const char *line, int len, unsigned flags)
 609{
 610        static const char *nneof = " No newline at end of file\n";
 611        const char *context, *reset, *set;
 612        switch (s) {
 613        case DIFF_SYMBOL_NO_LF_EOF:
 614                context = diff_get_color_opt(o, DIFF_CONTEXT);
 615                reset = diff_get_color_opt(o, DIFF_RESET);
 616                putc('\n', o->file);
 617                emit_line_0(o, context, reset, '\\',
 618                            nneof, strlen(nneof));
 619                break;
 620        case DIFF_SYMBOL_CONTEXT_FRAGINFO:
 621                emit_line(o, "", "", line, len);
 622                break;
 623        case DIFF_SYMBOL_CONTEXT_MARKER:
 624                context = diff_get_color_opt(o, DIFF_CONTEXT);
 625                reset = diff_get_color_opt(o, DIFF_RESET);
 626                emit_line(o, context, reset, line, len);
 627                break;
 628        case DIFF_SYMBOL_SEPARATOR:
 629                fprintf(o->file, "%s%c",
 630                        diff_line_prefix(o),
 631                        o->line_termination);
 632                break;
 633        case DIFF_SYMBOL_CONTEXT:
 634                set = diff_get_color_opt(o, DIFF_CONTEXT);
 635                reset = diff_get_color_opt(o, DIFF_RESET);
 636                emit_line_ws_markup(o, set, reset, line, len, ' ',
 637                                    flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
 638                break;
 639        case DIFF_SYMBOL_PLUS:
 640                set = diff_get_color_opt(o, DIFF_FILE_NEW);
 641                reset = diff_get_color_opt(o, DIFF_RESET);
 642                emit_line_ws_markup(o, set, reset, line, len, '+',
 643                                    flags & DIFF_SYMBOL_CONTENT_WS_MASK,
 644                                    flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
 645                break;
 646        case DIFF_SYMBOL_MINUS:
 647                set = diff_get_color_opt(o, DIFF_FILE_OLD);
 648                reset = diff_get_color_opt(o, DIFF_RESET);
 649                emit_line_ws_markup(o, set, reset, line, len, '-',
 650                                    flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
 651                break;
 652        default:
 653                die("BUG: unknown diff symbol");
 654        }
 655}
 656
 657static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 658{
 659        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 660              ecbdata->blank_at_eof_in_preimage &&
 661              ecbdata->blank_at_eof_in_postimage &&
 662              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 663              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 664                return 0;
 665        return ws_blank_line(line, len, ecbdata->ws_rule);
 666}
 667
 668static void emit_add_line(const char *reset,
 669                          struct emit_callback *ecbdata,
 670                          const char *line, int len)
 671{
 672        unsigned flags = WSEH_NEW | ecbdata->ws_rule;
 673        if (new_blank_line_at_eof(ecbdata, line, len))
 674                flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
 675
 676        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
 677}
 678
 679static void emit_del_line(const char *reset,
 680                          struct emit_callback *ecbdata,
 681                          const char *line, int len)
 682{
 683        unsigned flags = WSEH_OLD | ecbdata->ws_rule;
 684        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
 685}
 686
 687static void emit_context_line(const char *reset,
 688                              struct emit_callback *ecbdata,
 689                              const char *line, int len)
 690{
 691        unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
 692        emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
 693}
 694
 695static void emit_hunk_header(struct emit_callback *ecbdata,
 696                             const char *line, int len)
 697{
 698        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 699        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 700        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 701        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 702        static const char atat[2] = { '@', '@' };
 703        const char *cp, *ep;
 704        struct strbuf msgbuf = STRBUF_INIT;
 705        int org_len = len;
 706        int i = 1;
 707
 708        /*
 709         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 710         * it always is at least 10 bytes long.
 711         */
 712        if (len < 10 ||
 713            memcmp(line, atat, 2) ||
 714            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 715                emit_diff_symbol(ecbdata->opt,
 716                                 DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
 717                return;
 718        }
 719        ep += 2; /* skip over @@ */
 720
 721        /* The hunk header in fraginfo color */
 722        strbuf_addstr(&msgbuf, frag);
 723        strbuf_add(&msgbuf, line, ep - line);
 724        strbuf_addstr(&msgbuf, reset);
 725
 726        /*
 727         * trailing "\r\n"
 728         */
 729        for ( ; i < 3; i++)
 730                if (line[len - i] == '\r' || line[len - i] == '\n')
 731                        len--;
 732
 733        /* blank before the func header */
 734        for (cp = ep; ep - line < len; ep++)
 735                if (*ep != ' ' && *ep != '\t')
 736                        break;
 737        if (ep != cp) {
 738                strbuf_addstr(&msgbuf, context);
 739                strbuf_add(&msgbuf, cp, ep - cp);
 740                strbuf_addstr(&msgbuf, reset);
 741        }
 742
 743        if (ep < line + len) {
 744                strbuf_addstr(&msgbuf, func);
 745                strbuf_add(&msgbuf, ep, line + len - ep);
 746                strbuf_addstr(&msgbuf, reset);
 747        }
 748
 749        strbuf_add(&msgbuf, line + len, org_len - len);
 750        strbuf_complete_line(&msgbuf);
 751        emit_diff_symbol(ecbdata->opt,
 752                         DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
 753        strbuf_release(&msgbuf);
 754}
 755
 756static struct diff_tempfile *claim_diff_tempfile(void) {
 757        int i;
 758        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 759                if (!diff_temp[i].name)
 760                        return diff_temp + i;
 761        die("BUG: diff is failing to clean up its tempfiles");
 762}
 763
 764static void remove_tempfile(void)
 765{
 766        int i;
 767        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 768                if (is_tempfile_active(&diff_temp[i].tempfile))
 769                        delete_tempfile(&diff_temp[i].tempfile);
 770                diff_temp[i].name = NULL;
 771        }
 772}
 773
 774static void print_line_count(FILE *file, int count)
 775{
 776        switch (count) {
 777        case 0:
 778                fprintf(file, "0,0");
 779                break;
 780        case 1:
 781                fprintf(file, "1");
 782                break;
 783        default:
 784                fprintf(file, "1,%d", count);
 785                break;
 786        }
 787}
 788
 789static void emit_rewrite_lines(struct emit_callback *ecb,
 790                               int prefix, const char *data, int size)
 791{
 792        const char *endp = NULL;
 793        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 794
 795        while (0 < size) {
 796                int len;
 797
 798                endp = memchr(data, '\n', size);
 799                len = endp ? (endp - data + 1) : size;
 800                if (prefix != '+') {
 801                        ecb->lno_in_preimage++;
 802                        emit_del_line(reset, ecb, data, len);
 803                } else {
 804                        ecb->lno_in_postimage++;
 805                        emit_add_line(reset, ecb, data, len);
 806                }
 807                size -= len;
 808                data += len;
 809        }
 810        if (!endp)
 811                emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
 812}
 813
 814static void emit_rewrite_diff(const char *name_a,
 815                              const char *name_b,
 816                              struct diff_filespec *one,
 817                              struct diff_filespec *two,
 818                              struct userdiff_driver *textconv_one,
 819                              struct userdiff_driver *textconv_two,
 820                              struct diff_options *o)
 821{
 822        int lc_a, lc_b;
 823        const char *name_a_tab, *name_b_tab;
 824        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 825        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 826        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 827        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 828        const char *a_prefix, *b_prefix;
 829        char *data_one, *data_two;
 830        size_t size_one, size_two;
 831        struct emit_callback ecbdata;
 832        const char *line_prefix = diff_line_prefix(o);
 833
 834        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 835                a_prefix = o->b_prefix;
 836                b_prefix = o->a_prefix;
 837        } else {
 838                a_prefix = o->a_prefix;
 839                b_prefix = o->b_prefix;
 840        }
 841
 842        name_a += (*name_a == '/');
 843        name_b += (*name_b == '/');
 844        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 845        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 846
 847        strbuf_reset(&a_name);
 848        strbuf_reset(&b_name);
 849        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 850        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 851
 852        size_one = fill_textconv(textconv_one, one, &data_one);
 853        size_two = fill_textconv(textconv_two, two, &data_two);
 854
 855        memset(&ecbdata, 0, sizeof(ecbdata));
 856        ecbdata.color_diff = want_color(o->use_color);
 857        ecbdata.ws_rule = whitespace_rule(name_b);
 858        ecbdata.opt = o;
 859        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 860                mmfile_t mf1, mf2;
 861                mf1.ptr = (char *)data_one;
 862                mf2.ptr = (char *)data_two;
 863                mf1.size = size_one;
 864                mf2.size = size_two;
 865                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 866        }
 867        ecbdata.lno_in_preimage = 1;
 868        ecbdata.lno_in_postimage = 1;
 869
 870        lc_a = count_lines(data_one, size_one);
 871        lc_b = count_lines(data_two, size_two);
 872        fprintf(o->file,
 873                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 874                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 875                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 876                line_prefix, fraginfo);
 877        if (!o->irreversible_delete)
 878                print_line_count(o->file, lc_a);
 879        else
 880                fprintf(o->file, "?,?");
 881        fprintf(o->file, " +");
 882        print_line_count(o->file, lc_b);
 883        fprintf(o->file, " @@%s\n", reset);
 884        if (lc_a && !o->irreversible_delete)
 885                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 886        if (lc_b)
 887                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 888        if (textconv_one)
 889                free((char *)data_one);
 890        if (textconv_two)
 891                free((char *)data_two);
 892}
 893
 894struct diff_words_buffer {
 895        mmfile_t text;
 896        long alloc;
 897        struct diff_words_orig {
 898                const char *begin, *end;
 899        } *orig;
 900        int orig_nr, orig_alloc;
 901};
 902
 903static void diff_words_append(char *line, unsigned long len,
 904                struct diff_words_buffer *buffer)
 905{
 906        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 907        line++;
 908        len--;
 909        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 910        buffer->text.size += len;
 911        buffer->text.ptr[buffer->text.size] = '\0';
 912}
 913
 914struct diff_words_style_elem {
 915        const char *prefix;
 916        const char *suffix;
 917        const char *color; /* NULL; filled in by the setup code if
 918                            * color is enabled */
 919};
 920
 921struct diff_words_style {
 922        enum diff_words_type type;
 923        struct diff_words_style_elem new, old, ctx;
 924        const char *newline;
 925};
 926
 927static struct diff_words_style diff_words_styles[] = {
 928        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 929        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 930        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 931};
 932
 933struct diff_words_data {
 934        struct diff_words_buffer minus, plus;
 935        const char *current_plus;
 936        int last_minus;
 937        struct diff_options *opt;
 938        regex_t *word_regex;
 939        enum diff_words_type type;
 940        struct diff_words_style *style;
 941};
 942
 943static int fn_out_diff_words_write_helper(FILE *fp,
 944                                          struct diff_words_style_elem *st_el,
 945                                          const char *newline,
 946                                          size_t count, const char *buf,
 947                                          const char *line_prefix)
 948{
 949        int print = 0;
 950
 951        while (count) {
 952                char *p = memchr(buf, '\n', count);
 953                if (print)
 954                        fputs(line_prefix, fp);
 955                if (p != buf) {
 956                        if (st_el->color && fputs(st_el->color, fp) < 0)
 957                                return -1;
 958                        if (fputs(st_el->prefix, fp) < 0 ||
 959                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 960                            fputs(st_el->suffix, fp) < 0)
 961                                return -1;
 962                        if (st_el->color && *st_el->color
 963                            && fputs(GIT_COLOR_RESET, fp) < 0)
 964                                return -1;
 965                }
 966                if (!p)
 967                        return 0;
 968                if (fputs(newline, fp) < 0)
 969                        return -1;
 970                count -= p + 1 - buf;
 971                buf = p + 1;
 972                print = 1;
 973        }
 974        return 0;
 975}
 976
 977/*
 978 * '--color-words' algorithm can be described as:
 979 *
 980 *   1. collect the minus/plus lines of a diff hunk, divided into
 981 *      minus-lines and plus-lines;
 982 *
 983 *   2. break both minus-lines and plus-lines into words and
 984 *      place them into two mmfile_t with one word for each line;
 985 *
 986 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 987 *
 988 * And for the common parts of the both file, we output the plus side text.
 989 * diff_words->current_plus is used to trace the current position of the plus file
 990 * which printed. diff_words->last_minus is used to trace the last minus word
 991 * printed.
 992 *
 993 * For '--graph' to work with '--color-words', we need to output the graph prefix
 994 * on each line of color words output. Generally, there are two conditions on
 995 * which we should output the prefix.
 996 *
 997 *   1. diff_words->last_minus == 0 &&
 998 *      diff_words->current_plus == diff_words->plus.text.ptr
 999 *
1000 *      that is: the plus text must start as a new line, and if there is no minus
1001 *      word printed, a graph prefix must be printed.
1002 *
1003 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1004 *      *(diff_words->current_plus - 1) == '\n'
1005 *
1006 *      that is: a graph prefix must be printed following a '\n'
1007 */
1008static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1009{
1010        if ((diff_words->last_minus == 0 &&
1011                diff_words->current_plus == diff_words->plus.text.ptr) ||
1012                (diff_words->current_plus > diff_words->plus.text.ptr &&
1013                *(diff_words->current_plus - 1) == '\n')) {
1014                return 1;
1015        } else {
1016                return 0;
1017        }
1018}
1019
1020static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
1021{
1022        struct diff_words_data *diff_words = priv;
1023        struct diff_words_style *style = diff_words->style;
1024        int minus_first, minus_len, plus_first, plus_len;
1025        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1026        struct diff_options *opt = diff_words->opt;
1027        const char *line_prefix;
1028
1029        if (line[0] != '@' || parse_hunk_header(line, len,
1030                        &minus_first, &minus_len, &plus_first, &plus_len))
1031                return;
1032
1033        assert(opt);
1034        line_prefix = diff_line_prefix(opt);
1035
1036        /* POSIX requires that first be decremented by one if len == 0... */
1037        if (minus_len) {
1038                minus_begin = diff_words->minus.orig[minus_first].begin;
1039                minus_end =
1040                        diff_words->minus.orig[minus_first + minus_len - 1].end;
1041        } else
1042                minus_begin = minus_end =
1043                        diff_words->minus.orig[minus_first].end;
1044
1045        if (plus_len) {
1046                plus_begin = diff_words->plus.orig[plus_first].begin;
1047                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1048        } else
1049                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1050
1051        if (color_words_output_graph_prefix(diff_words)) {
1052                fputs(line_prefix, diff_words->opt->file);
1053        }
1054        if (diff_words->current_plus != plus_begin) {
1055                fn_out_diff_words_write_helper(diff_words->opt->file,
1056                                &style->ctx, style->newline,
1057                                plus_begin - diff_words->current_plus,
1058                                diff_words->current_plus, line_prefix);
1059                if (*(plus_begin - 1) == '\n')
1060                        fputs(line_prefix, diff_words->opt->file);
1061        }
1062        if (minus_begin != minus_end) {
1063                fn_out_diff_words_write_helper(diff_words->opt->file,
1064                                &style->old, style->newline,
1065                                minus_end - minus_begin, minus_begin,
1066                                line_prefix);
1067        }
1068        if (plus_begin != plus_end) {
1069                fn_out_diff_words_write_helper(diff_words->opt->file,
1070                                &style->new, style->newline,
1071                                plus_end - plus_begin, plus_begin,
1072                                line_prefix);
1073        }
1074
1075        diff_words->current_plus = plus_end;
1076        diff_words->last_minus = minus_first;
1077}
1078
1079/* This function starts looking at *begin, and returns 0 iff a word was found. */
1080static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1081                int *begin, int *end)
1082{
1083        if (word_regex && *begin < buffer->size) {
1084                regmatch_t match[1];
1085                if (!regexec_buf(word_regex, buffer->ptr + *begin,
1086                                 buffer->size - *begin, 1, match, 0)) {
1087                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1088                                        '\n', match[0].rm_eo - match[0].rm_so);
1089                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1090                        *begin += match[0].rm_so;
1091                        return *begin >= *end;
1092                }
1093                return -1;
1094        }
1095
1096        /* find the next word */
1097        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1098                (*begin)++;
1099        if (*begin >= buffer->size)
1100                return -1;
1101
1102        /* find the end of the word */
1103        *end = *begin + 1;
1104        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1105                (*end)++;
1106
1107        return 0;
1108}
1109
1110/*
1111 * This function splits the words in buffer->text, stores the list with
1112 * newline separator into out, and saves the offsets of the original words
1113 * in buffer->orig.
1114 */
1115static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1116                regex_t *word_regex)
1117{
1118        int i, j;
1119        long alloc = 0;
1120
1121        out->size = 0;
1122        out->ptr = NULL;
1123
1124        /* fake an empty "0th" word */
1125        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1126        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1127        buffer->orig_nr = 1;
1128
1129        for (i = 0; i < buffer->text.size; i++) {
1130                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1131                        return;
1132
1133                /* store original boundaries */
1134                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1135                                buffer->orig_alloc);
1136                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1137                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1138                buffer->orig_nr++;
1139
1140                /* store one word */
1141                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1142                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1143                out->ptr[out->size + j - i] = '\n';
1144                out->size += j - i + 1;
1145
1146                i = j - 1;
1147        }
1148}
1149
1150/* this executes the word diff on the accumulated buffers */
1151static void diff_words_show(struct diff_words_data *diff_words)
1152{
1153        xpparam_t xpp;
1154        xdemitconf_t xecfg;
1155        mmfile_t minus, plus;
1156        struct diff_words_style *style = diff_words->style;
1157
1158        struct diff_options *opt = diff_words->opt;
1159        const char *line_prefix;
1160
1161        assert(opt);
1162        line_prefix = diff_line_prefix(opt);
1163
1164        /* special case: only removal */
1165        if (!diff_words->plus.text.size) {
1166                fputs(line_prefix, diff_words->opt->file);
1167                fn_out_diff_words_write_helper(diff_words->opt->file,
1168                        &style->old, style->newline,
1169                        diff_words->minus.text.size,
1170                        diff_words->minus.text.ptr, line_prefix);
1171                diff_words->minus.text.size = 0;
1172                return;
1173        }
1174
1175        diff_words->current_plus = diff_words->plus.text.ptr;
1176        diff_words->last_minus = 0;
1177
1178        memset(&xpp, 0, sizeof(xpp));
1179        memset(&xecfg, 0, sizeof(xecfg));
1180        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1181        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1182        xpp.flags = 0;
1183        /* as only the hunk header will be parsed, we need a 0-context */
1184        xecfg.ctxlen = 0;
1185        if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1186                          &xpp, &xecfg))
1187                die("unable to generate word diff");
1188        free(minus.ptr);
1189        free(plus.ptr);
1190        if (diff_words->current_plus != diff_words->plus.text.ptr +
1191                        diff_words->plus.text.size) {
1192                if (color_words_output_graph_prefix(diff_words))
1193                        fputs(line_prefix, diff_words->opt->file);
1194                fn_out_diff_words_write_helper(diff_words->opt->file,
1195                        &style->ctx, style->newline,
1196                        diff_words->plus.text.ptr + diff_words->plus.text.size
1197                        - diff_words->current_plus, diff_words->current_plus,
1198                        line_prefix);
1199        }
1200        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1201}
1202
1203/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1204static void diff_words_flush(struct emit_callback *ecbdata)
1205{
1206        if (ecbdata->diff_words->minus.text.size ||
1207            ecbdata->diff_words->plus.text.size)
1208                diff_words_show(ecbdata->diff_words);
1209}
1210
1211static void diff_filespec_load_driver(struct diff_filespec *one)
1212{
1213        /* Use already-loaded driver */
1214        if (one->driver)
1215                return;
1216
1217        if (S_ISREG(one->mode))
1218                one->driver = userdiff_find_by_path(one->path);
1219
1220        /* Fallback to default settings */
1221        if (!one->driver)
1222                one->driver = userdiff_find_by_name("default");
1223}
1224
1225static const char *userdiff_word_regex(struct diff_filespec *one)
1226{
1227        diff_filespec_load_driver(one);
1228        return one->driver->word_regex;
1229}
1230
1231static void init_diff_words_data(struct emit_callback *ecbdata,
1232                                 struct diff_options *orig_opts,
1233                                 struct diff_filespec *one,
1234                                 struct diff_filespec *two)
1235{
1236        int i;
1237        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1238        memcpy(o, orig_opts, sizeof(struct diff_options));
1239
1240        ecbdata->diff_words =
1241                xcalloc(1, sizeof(struct diff_words_data));
1242        ecbdata->diff_words->type = o->word_diff;
1243        ecbdata->diff_words->opt = o;
1244        if (!o->word_regex)
1245                o->word_regex = userdiff_word_regex(one);
1246        if (!o->word_regex)
1247                o->word_regex = userdiff_word_regex(two);
1248        if (!o->word_regex)
1249                o->word_regex = diff_word_regex_cfg;
1250        if (o->word_regex) {
1251                ecbdata->diff_words->word_regex = (regex_t *)
1252                        xmalloc(sizeof(regex_t));
1253                if (regcomp(ecbdata->diff_words->word_regex,
1254                            o->word_regex,
1255                            REG_EXTENDED | REG_NEWLINE))
1256                        die ("Invalid regular expression: %s",
1257                             o->word_regex);
1258        }
1259        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1260                if (o->word_diff == diff_words_styles[i].type) {
1261                        ecbdata->diff_words->style =
1262                                &diff_words_styles[i];
1263                        break;
1264                }
1265        }
1266        if (want_color(o->use_color)) {
1267                struct diff_words_style *st = ecbdata->diff_words->style;
1268                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1269                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1270                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1271        }
1272}
1273
1274static void free_diff_words_data(struct emit_callback *ecbdata)
1275{
1276        if (ecbdata->diff_words) {
1277                diff_words_flush(ecbdata);
1278                free (ecbdata->diff_words->opt);
1279                free (ecbdata->diff_words->minus.text.ptr);
1280                free (ecbdata->diff_words->minus.orig);
1281                free (ecbdata->diff_words->plus.text.ptr);
1282                free (ecbdata->diff_words->plus.orig);
1283                if (ecbdata->diff_words->word_regex) {
1284                        regfree(ecbdata->diff_words->word_regex);
1285                        free(ecbdata->diff_words->word_regex);
1286                }
1287                FREE_AND_NULL(ecbdata->diff_words);
1288        }
1289}
1290
1291const char *diff_get_color(int diff_use_color, enum color_diff ix)
1292{
1293        if (want_color(diff_use_color))
1294                return diff_colors[ix];
1295        return "";
1296}
1297
1298const char *diff_line_prefix(struct diff_options *opt)
1299{
1300        struct strbuf *msgbuf;
1301        if (!opt->output_prefix)
1302                return "";
1303
1304        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1305        return msgbuf->buf;
1306}
1307
1308static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1309{
1310        const char *cp;
1311        unsigned long allot;
1312        size_t l = len;
1313
1314        if (ecb->truncate)
1315                return ecb->truncate(line, len);
1316        cp = line;
1317        allot = l;
1318        while (0 < l) {
1319                (void) utf8_width(&cp, &l);
1320                if (!cp)
1321                        break; /* truncated in the middle? */
1322        }
1323        return allot - l;
1324}
1325
1326static void find_lno(const char *line, struct emit_callback *ecbdata)
1327{
1328        const char *p;
1329        ecbdata->lno_in_preimage = 0;
1330        ecbdata->lno_in_postimage = 0;
1331        p = strchr(line, '-');
1332        if (!p)
1333                return; /* cannot happen */
1334        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1335        p = strchr(p, '+');
1336        if (!p)
1337                return; /* cannot happen */
1338        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1339}
1340
1341static void fn_out_consume(void *priv, char *line, unsigned long len)
1342{
1343        struct emit_callback *ecbdata = priv;
1344        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1345        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1346        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1347        struct diff_options *o = ecbdata->opt;
1348        const char *line_prefix = diff_line_prefix(o);
1349
1350        o->found_changes = 1;
1351
1352        if (ecbdata->header) {
1353                fprintf(o->file, "%s", ecbdata->header->buf);
1354                strbuf_reset(ecbdata->header);
1355                ecbdata->header = NULL;
1356        }
1357
1358        if (ecbdata->label_path[0]) {
1359                const char *name_a_tab, *name_b_tab;
1360
1361                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1362                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1363
1364                fprintf(o->file, "%s%s--- %s%s%s\n",
1365                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1366                fprintf(o->file, "%s%s+++ %s%s%s\n",
1367                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1368                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1369        }
1370
1371        if (diff_suppress_blank_empty
1372            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1373                line[0] = '\n';
1374                len = 1;
1375        }
1376
1377        if (line[0] == '@') {
1378                if (ecbdata->diff_words)
1379                        diff_words_flush(ecbdata);
1380                len = sane_truncate_line(ecbdata, line, len);
1381                find_lno(line, ecbdata);
1382                emit_hunk_header(ecbdata, line, len);
1383                return;
1384        }
1385
1386        if (ecbdata->diff_words) {
1387                if (line[0] == '-') {
1388                        diff_words_append(line, len,
1389                                          &ecbdata->diff_words->minus);
1390                        return;
1391                } else if (line[0] == '+') {
1392                        diff_words_append(line, len,
1393                                          &ecbdata->diff_words->plus);
1394                        return;
1395                } else if (starts_with(line, "\\ ")) {
1396                        /*
1397                         * Eat the "no newline at eof" marker as if we
1398                         * saw a "+" or "-" line with nothing on it,
1399                         * and return without diff_words_flush() to
1400                         * defer processing. If this is the end of
1401                         * preimage, more "+" lines may come after it.
1402                         */
1403                        return;
1404                }
1405                diff_words_flush(ecbdata);
1406                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1407                        emit_line(o, context, reset, line, len);
1408                        fputs("~\n", o->file);
1409                } else {
1410                        /*
1411                         * Skip the prefix character, if any.  With
1412                         * diff_suppress_blank_empty, there may be
1413                         * none.
1414                         */
1415                        if (line[0] != '\n') {
1416                              line++;
1417                              len--;
1418                        }
1419                        emit_line(o, context, reset, line, len);
1420                }
1421                return;
1422        }
1423
1424        switch (line[0]) {
1425        case '+':
1426                ecbdata->lno_in_postimage++;
1427                emit_add_line(reset, ecbdata, line + 1, len - 1);
1428                break;
1429        case '-':
1430                ecbdata->lno_in_preimage++;
1431                emit_del_line(reset, ecbdata, line + 1, len - 1);
1432                break;
1433        case ' ':
1434                ecbdata->lno_in_postimage++;
1435                ecbdata->lno_in_preimage++;
1436                emit_context_line(reset, ecbdata, line + 1, len - 1);
1437                break;
1438        default:
1439                /* incomplete line at the end */
1440                ecbdata->lno_in_preimage++;
1441                emit_line(o, diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
1442                          reset, line, len);
1443                break;
1444        }
1445}
1446
1447static char *pprint_rename(const char *a, const char *b)
1448{
1449        const char *old = a;
1450        const char *new = b;
1451        struct strbuf name = STRBUF_INIT;
1452        int pfx_length, sfx_length;
1453        int pfx_adjust_for_slash;
1454        int len_a = strlen(a);
1455        int len_b = strlen(b);
1456        int a_midlen, b_midlen;
1457        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1458        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1459
1460        if (qlen_a || qlen_b) {
1461                quote_c_style(a, &name, NULL, 0);
1462                strbuf_addstr(&name, " => ");
1463                quote_c_style(b, &name, NULL, 0);
1464                return strbuf_detach(&name, NULL);
1465        }
1466
1467        /* Find common prefix */
1468        pfx_length = 0;
1469        while (*old && *new && *old == *new) {
1470                if (*old == '/')
1471                        pfx_length = old - a + 1;
1472                old++;
1473                new++;
1474        }
1475
1476        /* Find common suffix */
1477        old = a + len_a;
1478        new = b + len_b;
1479        sfx_length = 0;
1480        /*
1481         * If there is a common prefix, it must end in a slash.  In
1482         * that case we let this loop run 1 into the prefix to see the
1483         * same slash.
1484         *
1485         * If there is no common prefix, we cannot do this as it would
1486         * underrun the input strings.
1487         */
1488        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1489        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1490               b + pfx_length - pfx_adjust_for_slash <= new &&
1491               *old == *new) {
1492                if (*old == '/')
1493                        sfx_length = len_a - (old - a);
1494                old--;
1495                new--;
1496        }
1497
1498        /*
1499         * pfx{mid-a => mid-b}sfx
1500         * {pfx-a => pfx-b}sfx
1501         * pfx{sfx-a => sfx-b}
1502         * name-a => name-b
1503         */
1504        a_midlen = len_a - pfx_length - sfx_length;
1505        b_midlen = len_b - pfx_length - sfx_length;
1506        if (a_midlen < 0)
1507                a_midlen = 0;
1508        if (b_midlen < 0)
1509                b_midlen = 0;
1510
1511        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1512        if (pfx_length + sfx_length) {
1513                strbuf_add(&name, a, pfx_length);
1514                strbuf_addch(&name, '{');
1515        }
1516        strbuf_add(&name, a + pfx_length, a_midlen);
1517        strbuf_addstr(&name, " => ");
1518        strbuf_add(&name, b + pfx_length, b_midlen);
1519        if (pfx_length + sfx_length) {
1520                strbuf_addch(&name, '}');
1521                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1522        }
1523        return strbuf_detach(&name, NULL);
1524}
1525
1526struct diffstat_t {
1527        int nr;
1528        int alloc;
1529        struct diffstat_file {
1530                char *from_name;
1531                char *name;
1532                char *print_name;
1533                unsigned is_unmerged:1;
1534                unsigned is_binary:1;
1535                unsigned is_renamed:1;
1536                unsigned is_interesting:1;
1537                uintmax_t added, deleted;
1538        } **files;
1539};
1540
1541static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1542                                          const char *name_a,
1543                                          const char *name_b)
1544{
1545        struct diffstat_file *x;
1546        x = xcalloc(1, sizeof(*x));
1547        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1548        diffstat->files[diffstat->nr++] = x;
1549        if (name_b) {
1550                x->from_name = xstrdup(name_a);
1551                x->name = xstrdup(name_b);
1552                x->is_renamed = 1;
1553        }
1554        else {
1555                x->from_name = NULL;
1556                x->name = xstrdup(name_a);
1557        }
1558        return x;
1559}
1560
1561static void diffstat_consume(void *priv, char *line, unsigned long len)
1562{
1563        struct diffstat_t *diffstat = priv;
1564        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1565
1566        if (line[0] == '+')
1567                x->added++;
1568        else if (line[0] == '-')
1569                x->deleted++;
1570}
1571
1572const char mime_boundary_leader[] = "------------";
1573
1574static int scale_linear(int it, int width, int max_change)
1575{
1576        if (!it)
1577                return 0;
1578        /*
1579         * make sure that at least one '-' or '+' is printed if
1580         * there is any change to this path. The easiest way is to
1581         * scale linearly as if the alloted width is one column shorter
1582         * than it is, and then add 1 to the result.
1583         */
1584        return 1 + (it * (width - 1) / max_change);
1585}
1586
1587static void show_name(FILE *file,
1588                      const char *prefix, const char *name, int len)
1589{
1590        fprintf(file, " %s%-*s |", prefix, len, name);
1591}
1592
1593static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1594{
1595        if (cnt <= 0)
1596                return;
1597        fprintf(file, "%s", set);
1598        while (cnt--)
1599                putc(ch, file);
1600        fprintf(file, "%s", reset);
1601}
1602
1603static void fill_print_name(struct diffstat_file *file)
1604{
1605        char *pname;
1606
1607        if (file->print_name)
1608                return;
1609
1610        if (!file->is_renamed) {
1611                struct strbuf buf = STRBUF_INIT;
1612                if (quote_c_style(file->name, &buf, NULL, 0)) {
1613                        pname = strbuf_detach(&buf, NULL);
1614                } else {
1615                        pname = file->name;
1616                        strbuf_release(&buf);
1617                }
1618        } else {
1619                pname = pprint_rename(file->from_name, file->name);
1620        }
1621        file->print_name = pname;
1622}
1623
1624int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1625{
1626        struct strbuf sb = STRBUF_INIT;
1627        int ret;
1628
1629        if (!files) {
1630                assert(insertions == 0 && deletions == 0);
1631                return fprintf(fp, "%s\n", " 0 files changed");
1632        }
1633
1634        strbuf_addf(&sb,
1635                    (files == 1) ? " %d file changed" : " %d files changed",
1636                    files);
1637
1638        /*
1639         * For binary diff, the caller may want to print "x files
1640         * changed" with insertions == 0 && deletions == 0.
1641         *
1642         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1643         * is probably less confusing (i.e skip over "2 files changed
1644         * but nothing about added/removed lines? Is this a bug in Git?").
1645         */
1646        if (insertions || deletions == 0) {
1647                strbuf_addf(&sb,
1648                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1649                            insertions);
1650        }
1651
1652        if (deletions || insertions == 0) {
1653                strbuf_addf(&sb,
1654                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1655                            deletions);
1656        }
1657        strbuf_addch(&sb, '\n');
1658        ret = fputs(sb.buf, fp);
1659        strbuf_release(&sb);
1660        return ret;
1661}
1662
1663static void show_stats(struct diffstat_t *data, struct diff_options *options)
1664{
1665        int i, len, add, del, adds = 0, dels = 0;
1666        uintmax_t max_change = 0, max_len = 0;
1667        int total_files = data->nr, count;
1668        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1669        const char *reset, *add_c, *del_c;
1670        const char *line_prefix = "";
1671        int extra_shown = 0;
1672
1673        if (data->nr == 0)
1674                return;
1675
1676        line_prefix = diff_line_prefix(options);
1677        count = options->stat_count ? options->stat_count : data->nr;
1678
1679        reset = diff_get_color_opt(options, DIFF_RESET);
1680        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1681        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1682
1683        /*
1684         * Find the longest filename and max number of changes
1685         */
1686        for (i = 0; (i < count) && (i < data->nr); i++) {
1687                struct diffstat_file *file = data->files[i];
1688                uintmax_t change = file->added + file->deleted;
1689
1690                if (!file->is_interesting && (change == 0)) {
1691                        count++; /* not shown == room for one more */
1692                        continue;
1693                }
1694                fill_print_name(file);
1695                len = strlen(file->print_name);
1696                if (max_len < len)
1697                        max_len = len;
1698
1699                if (file->is_unmerged) {
1700                        /* "Unmerged" is 8 characters */
1701                        bin_width = bin_width < 8 ? 8 : bin_width;
1702                        continue;
1703                }
1704                if (file->is_binary) {
1705                        /* "Bin XXX -> YYY bytes" */
1706                        int w = 14 + decimal_width(file->added)
1707                                + decimal_width(file->deleted);
1708                        bin_width = bin_width < w ? w : bin_width;
1709                        /* Display change counts aligned with "Bin" */
1710                        number_width = 3;
1711                        continue;
1712                }
1713
1714                if (max_change < change)
1715                        max_change = change;
1716        }
1717        count = i; /* where we can stop scanning in data->files[] */
1718
1719        /*
1720         * We have width = stat_width or term_columns() columns total.
1721         * We want a maximum of min(max_len, stat_name_width) for the name part.
1722         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1723         * We also need 1 for " " and 4 + decimal_width(max_change)
1724         * for " | NNNN " and one the empty column at the end, altogether
1725         * 6 + decimal_width(max_change).
1726         *
1727         * If there's not enough space, we will use the smaller of
1728         * stat_name_width (if set) and 5/8*width for the filename,
1729         * and the rest for constant elements + graph part, but no more
1730         * than stat_graph_width for the graph part.
1731         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1732         * for the standard terminal size).
1733         *
1734         * In other words: stat_width limits the maximum width, and
1735         * stat_name_width fixes the maximum width of the filename,
1736         * and is also used to divide available columns if there
1737         * aren't enough.
1738         *
1739         * Binary files are displayed with "Bin XXX -> YYY bytes"
1740         * instead of the change count and graph. This part is treated
1741         * similarly to the graph part, except that it is not
1742         * "scaled". If total width is too small to accommodate the
1743         * guaranteed minimum width of the filename part and the
1744         * separators and this message, this message will "overflow"
1745         * making the line longer than the maximum width.
1746         */
1747
1748        if (options->stat_width == -1)
1749                width = term_columns() - strlen(line_prefix);
1750        else
1751                width = options->stat_width ? options->stat_width : 80;
1752        number_width = decimal_width(max_change) > number_width ?
1753                decimal_width(max_change) : number_width;
1754
1755        if (options->stat_graph_width == -1)
1756                options->stat_graph_width = diff_stat_graph_width;
1757
1758        /*
1759         * Guarantee 3/8*16==6 for the graph part
1760         * and 5/8*16==10 for the filename part
1761         */
1762        if (width < 16 + 6 + number_width)
1763                width = 16 + 6 + number_width;
1764
1765        /*
1766         * First assign sizes that are wanted, ignoring available width.
1767         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1768         * starting from "XXX" should fit in graph_width.
1769         */
1770        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1771        if (options->stat_graph_width &&
1772            options->stat_graph_width < graph_width)
1773                graph_width = options->stat_graph_width;
1774
1775        name_width = (options->stat_name_width > 0 &&
1776                      options->stat_name_width < max_len) ?
1777                options->stat_name_width : max_len;
1778
1779        /*
1780         * Adjust adjustable widths not to exceed maximum width
1781         */
1782        if (name_width + number_width + 6 + graph_width > width) {
1783                if (graph_width > width * 3/8 - number_width - 6) {
1784                        graph_width = width * 3/8 - number_width - 6;
1785                        if (graph_width < 6)
1786                                graph_width = 6;
1787                }
1788
1789                if (options->stat_graph_width &&
1790                    graph_width > options->stat_graph_width)
1791                        graph_width = options->stat_graph_width;
1792                if (name_width > width - number_width - 6 - graph_width)
1793                        name_width = width - number_width - 6 - graph_width;
1794                else
1795                        graph_width = width - number_width - 6 - name_width;
1796        }
1797
1798        /*
1799         * From here name_width is the width of the name area,
1800         * and graph_width is the width of the graph area.
1801         * max_change is used to scale graph properly.
1802         */
1803        for (i = 0; i < count; i++) {
1804                const char *prefix = "";
1805                struct diffstat_file *file = data->files[i];
1806                char *name = file->print_name;
1807                uintmax_t added = file->added;
1808                uintmax_t deleted = file->deleted;
1809                int name_len;
1810
1811                if (!file->is_interesting && (added + deleted == 0))
1812                        continue;
1813
1814                /*
1815                 * "scale" the filename
1816                 */
1817                len = name_width;
1818                name_len = strlen(name);
1819                if (name_width < name_len) {
1820                        char *slash;
1821                        prefix = "...";
1822                        len -= 3;
1823                        name += name_len - len;
1824                        slash = strchr(name, '/');
1825                        if (slash)
1826                                name = slash;
1827                }
1828
1829                if (file->is_binary) {
1830                        fprintf(options->file, "%s", line_prefix);
1831                        show_name(options->file, prefix, name, len);
1832                        fprintf(options->file, " %*s", number_width, "Bin");
1833                        if (!added && !deleted) {
1834                                putc('\n', options->file);
1835                                continue;
1836                        }
1837                        fprintf(options->file, " %s%"PRIuMAX"%s",
1838                                del_c, deleted, reset);
1839                        fprintf(options->file, " -> ");
1840                        fprintf(options->file, "%s%"PRIuMAX"%s",
1841                                add_c, added, reset);
1842                        fprintf(options->file, " bytes");
1843                        fprintf(options->file, "\n");
1844                        continue;
1845                }
1846                else if (file->is_unmerged) {
1847                        fprintf(options->file, "%s", line_prefix);
1848                        show_name(options->file, prefix, name, len);
1849                        fprintf(options->file, " Unmerged\n");
1850                        continue;
1851                }
1852
1853                /*
1854                 * scale the add/delete
1855                 */
1856                add = added;
1857                del = deleted;
1858
1859                if (graph_width <= max_change) {
1860                        int total = scale_linear(add + del, graph_width, max_change);
1861                        if (total < 2 && add && del)
1862                                /* width >= 2 due to the sanity check */
1863                                total = 2;
1864                        if (add < del) {
1865                                add = scale_linear(add, graph_width, max_change);
1866                                del = total - add;
1867                        } else {
1868                                del = scale_linear(del, graph_width, max_change);
1869                                add = total - del;
1870                        }
1871                }
1872                fprintf(options->file, "%s", line_prefix);
1873                show_name(options->file, prefix, name, len);
1874                fprintf(options->file, " %*"PRIuMAX"%s",
1875                        number_width, added + deleted,
1876                        added + deleted ? " " : "");
1877                show_graph(options->file, '+', add, add_c, reset);
1878                show_graph(options->file, '-', del, del_c, reset);
1879                fprintf(options->file, "\n");
1880        }
1881
1882        for (i = 0; i < data->nr; i++) {
1883                struct diffstat_file *file = data->files[i];
1884                uintmax_t added = file->added;
1885                uintmax_t deleted = file->deleted;
1886
1887                if (file->is_unmerged ||
1888                    (!file->is_interesting && (added + deleted == 0))) {
1889                        total_files--;
1890                        continue;
1891                }
1892
1893                if (!file->is_binary) {
1894                        adds += added;
1895                        dels += deleted;
1896                }
1897                if (i < count)
1898                        continue;
1899                if (!extra_shown)
1900                        fprintf(options->file, "%s ...\n", line_prefix);
1901                extra_shown = 1;
1902        }
1903        fprintf(options->file, "%s", line_prefix);
1904        print_stat_summary(options->file, total_files, adds, dels);
1905}
1906
1907static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1908{
1909        int i, adds = 0, dels = 0, total_files = data->nr;
1910
1911        if (data->nr == 0)
1912                return;
1913
1914        for (i = 0; i < data->nr; i++) {
1915                int added = data->files[i]->added;
1916                int deleted= data->files[i]->deleted;
1917
1918                if (data->files[i]->is_unmerged ||
1919                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1920                        total_files--;
1921                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1922                        adds += added;
1923                        dels += deleted;
1924                }
1925        }
1926        fprintf(options->file, "%s", diff_line_prefix(options));
1927        print_stat_summary(options->file, total_files, adds, dels);
1928}
1929
1930static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1931{
1932        int i;
1933
1934        if (data->nr == 0)
1935                return;
1936
1937        for (i = 0; i < data->nr; i++) {
1938                struct diffstat_file *file = data->files[i];
1939
1940                fprintf(options->file, "%s", diff_line_prefix(options));
1941
1942                if (file->is_binary)
1943                        fprintf(options->file, "-\t-\t");
1944                else
1945                        fprintf(options->file,
1946                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1947                                file->added, file->deleted);
1948                if (options->line_termination) {
1949                        fill_print_name(file);
1950                        if (!file->is_renamed)
1951                                write_name_quoted(file->name, options->file,
1952                                                  options->line_termination);
1953                        else {
1954                                fputs(file->print_name, options->file);
1955                                putc(options->line_termination, options->file);
1956                        }
1957                } else {
1958                        if (file->is_renamed) {
1959                                putc('\0', options->file);
1960                                write_name_quoted(file->from_name, options->file, '\0');
1961                        }
1962                        write_name_quoted(file->name, options->file, '\0');
1963                }
1964        }
1965}
1966
1967struct dirstat_file {
1968        const char *name;
1969        unsigned long changed;
1970};
1971
1972struct dirstat_dir {
1973        struct dirstat_file *files;
1974        int alloc, nr, permille, cumulative;
1975};
1976
1977static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1978                unsigned long changed, const char *base, int baselen)
1979{
1980        unsigned long this_dir = 0;
1981        unsigned int sources = 0;
1982        const char *line_prefix = diff_line_prefix(opt);
1983
1984        while (dir->nr) {
1985                struct dirstat_file *f = dir->files;
1986                int namelen = strlen(f->name);
1987                unsigned long this;
1988                char *slash;
1989
1990                if (namelen < baselen)
1991                        break;
1992                if (memcmp(f->name, base, baselen))
1993                        break;
1994                slash = strchr(f->name + baselen, '/');
1995                if (slash) {
1996                        int newbaselen = slash + 1 - f->name;
1997                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1998                        sources++;
1999                } else {
2000                        this = f->changed;
2001                        dir->files++;
2002                        dir->nr--;
2003                        sources += 2;
2004                }
2005                this_dir += this;
2006        }
2007
2008        /*
2009         * We don't report dirstat's for
2010         *  - the top level
2011         *  - or cases where everything came from a single directory
2012         *    under this directory (sources == 1).
2013         */
2014        if (baselen && sources != 1) {
2015                if (this_dir) {
2016                        int permille = this_dir * 1000 / changed;
2017                        if (permille >= dir->permille) {
2018                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2019                                        permille / 10, permille % 10, baselen, base);
2020                                if (!dir->cumulative)
2021                                        return 0;
2022                        }
2023                }
2024        }
2025        return this_dir;
2026}
2027
2028static int dirstat_compare(const void *_a, const void *_b)
2029{
2030        const struct dirstat_file *a = _a;
2031        const struct dirstat_file *b = _b;
2032        return strcmp(a->name, b->name);
2033}
2034
2035static void show_dirstat(struct diff_options *options)
2036{
2037        int i;
2038        unsigned long changed;
2039        struct dirstat_dir dir;
2040        struct diff_queue_struct *q = &diff_queued_diff;
2041
2042        dir.files = NULL;
2043        dir.alloc = 0;
2044        dir.nr = 0;
2045        dir.permille = options->dirstat_permille;
2046        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2047
2048        changed = 0;
2049        for (i = 0; i < q->nr; i++) {
2050                struct diff_filepair *p = q->queue[i];
2051                const char *name;
2052                unsigned long copied, added, damage;
2053                int content_changed;
2054
2055                name = p->two->path ? p->two->path : p->one->path;
2056
2057                if (p->one->oid_valid && p->two->oid_valid)
2058                        content_changed = oidcmp(&p->one->oid, &p->two->oid);
2059                else
2060                        content_changed = 1;
2061
2062                if (!content_changed) {
2063                        /*
2064                         * The SHA1 has not changed, so pre-/post-content is
2065                         * identical. We can therefore skip looking at the
2066                         * file contents altogether.
2067                         */
2068                        damage = 0;
2069                        goto found_damage;
2070                }
2071
2072                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
2073                        /*
2074                         * In --dirstat-by-file mode, we don't really need to
2075                         * look at the actual file contents at all.
2076                         * The fact that the SHA1 changed is enough for us to
2077                         * add this file to the list of results
2078                         * (with each file contributing equal damage).
2079                         */
2080                        damage = 1;
2081                        goto found_damage;
2082                }
2083
2084                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2085                        diff_populate_filespec(p->one, 0);
2086                        diff_populate_filespec(p->two, 0);
2087                        diffcore_count_changes(p->one, p->two, NULL, NULL,
2088                                               &copied, &added);
2089                        diff_free_filespec_data(p->one);
2090                        diff_free_filespec_data(p->two);
2091                } else if (DIFF_FILE_VALID(p->one)) {
2092                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2093                        copied = added = 0;
2094                        diff_free_filespec_data(p->one);
2095                } else if (DIFF_FILE_VALID(p->two)) {
2096                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2097                        copied = 0;
2098                        added = p->two->size;
2099                        diff_free_filespec_data(p->two);
2100                } else
2101                        continue;
2102
2103                /*
2104                 * Original minus copied is the removed material,
2105                 * added is the new material.  They are both damages
2106                 * made to the preimage.
2107                 * If the resulting damage is zero, we know that
2108                 * diffcore_count_changes() considers the two entries to
2109                 * be identical, but since content_changed is true, we
2110                 * know that there must have been _some_ kind of change,
2111                 * so we force all entries to have damage > 0.
2112                 */
2113                damage = (p->one->size - copied) + added;
2114                if (!damage)
2115                        damage = 1;
2116
2117found_damage:
2118                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2119                dir.files[dir.nr].name = name;
2120                dir.files[dir.nr].changed = damage;
2121                changed += damage;
2122                dir.nr++;
2123        }
2124
2125        /* This can happen even with many files, if everything was renames */
2126        if (!changed)
2127                return;
2128
2129        /* Show all directories with more than x% of the changes */
2130        QSORT(dir.files, dir.nr, dirstat_compare);
2131        gather_dirstat(options, &dir, changed, "", 0);
2132}
2133
2134static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2135{
2136        int i;
2137        unsigned long changed;
2138        struct dirstat_dir dir;
2139
2140        if (data->nr == 0)
2141                return;
2142
2143        dir.files = NULL;
2144        dir.alloc = 0;
2145        dir.nr = 0;
2146        dir.permille = options->dirstat_permille;
2147        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2148
2149        changed = 0;
2150        for (i = 0; i < data->nr; i++) {
2151                struct diffstat_file *file = data->files[i];
2152                unsigned long damage = file->added + file->deleted;
2153                if (file->is_binary)
2154                        /*
2155                         * binary files counts bytes, not lines. Must find some
2156                         * way to normalize binary bytes vs. textual lines.
2157                         * The following heuristic assumes that there are 64
2158                         * bytes per "line".
2159                         * This is stupid and ugly, but very cheap...
2160                         */
2161                        damage = (damage + 63) / 64;
2162                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2163                dir.files[dir.nr].name = file->name;
2164                dir.files[dir.nr].changed = damage;
2165                changed += damage;
2166                dir.nr++;
2167        }
2168
2169        /* This can happen even with many files, if everything was renames */
2170        if (!changed)
2171                return;
2172
2173        /* Show all directories with more than x% of the changes */
2174        QSORT(dir.files, dir.nr, dirstat_compare);
2175        gather_dirstat(options, &dir, changed, "", 0);
2176}
2177
2178static void free_diffstat_info(struct diffstat_t *diffstat)
2179{
2180        int i;
2181        for (i = 0; i < diffstat->nr; i++) {
2182                struct diffstat_file *f = diffstat->files[i];
2183                if (f->name != f->print_name)
2184                        free(f->print_name);
2185                free(f->name);
2186                free(f->from_name);
2187                free(f);
2188        }
2189        free(diffstat->files);
2190}
2191
2192struct checkdiff_t {
2193        const char *filename;
2194        int lineno;
2195        int conflict_marker_size;
2196        struct diff_options *o;
2197        unsigned ws_rule;
2198        unsigned status;
2199};
2200
2201static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2202{
2203        char firstchar;
2204        int cnt;
2205
2206        if (len < marker_size + 1)
2207                return 0;
2208        firstchar = line[0];
2209        switch (firstchar) {
2210        case '=': case '>': case '<': case '|':
2211                break;
2212        default:
2213                return 0;
2214        }
2215        for (cnt = 1; cnt < marker_size; cnt++)
2216                if (line[cnt] != firstchar)
2217                        return 0;
2218        /* line[1] thru line[marker_size-1] are same as firstchar */
2219        if (len < marker_size + 1 || !isspace(line[marker_size]))
2220                return 0;
2221        return 1;
2222}
2223
2224static void checkdiff_consume(void *priv, char *line, unsigned long len)
2225{
2226        struct checkdiff_t *data = priv;
2227        int marker_size = data->conflict_marker_size;
2228        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2229        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2230        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2231        char *err;
2232        const char *line_prefix;
2233
2234        assert(data->o);
2235        line_prefix = diff_line_prefix(data->o);
2236
2237        if (line[0] == '+') {
2238                unsigned bad;
2239                data->lineno++;
2240                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2241                        data->status |= 1;
2242                        fprintf(data->o->file,
2243                                "%s%s:%d: leftover conflict marker\n",
2244                                line_prefix, data->filename, data->lineno);
2245                }
2246                bad = ws_check(line + 1, len - 1, data->ws_rule);
2247                if (!bad)
2248                        return;
2249                data->status |= bad;
2250                err = whitespace_error_string(bad);
2251                fprintf(data->o->file, "%s%s:%d: %s.\n",
2252                        line_prefix, data->filename, data->lineno, err);
2253                free(err);
2254                emit_line(data->o, set, reset, line, 1);
2255                ws_check_emit(line + 1, len - 1, data->ws_rule,
2256                              data->o->file, set, reset, ws);
2257        } else if (line[0] == ' ') {
2258                data->lineno++;
2259        } else if (line[0] == '@') {
2260                char *plus = strchr(line, '+');
2261                if (plus)
2262                        data->lineno = strtol(plus, NULL, 10) - 1;
2263                else
2264                        die("invalid diff");
2265        }
2266}
2267
2268static unsigned char *deflate_it(char *data,
2269                                 unsigned long size,
2270                                 unsigned long *result_size)
2271{
2272        int bound;
2273        unsigned char *deflated;
2274        git_zstream stream;
2275
2276        git_deflate_init(&stream, zlib_compression_level);
2277        bound = git_deflate_bound(&stream, size);
2278        deflated = xmalloc(bound);
2279        stream.next_out = deflated;
2280        stream.avail_out = bound;
2281
2282        stream.next_in = (unsigned char *)data;
2283        stream.avail_in = size;
2284        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2285                ; /* nothing */
2286        git_deflate_end(&stream);
2287        *result_size = stream.total_out;
2288        return deflated;
2289}
2290
2291static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2292                                  const char *prefix)
2293{
2294        void *cp;
2295        void *delta;
2296        void *deflated;
2297        void *data;
2298        unsigned long orig_size;
2299        unsigned long delta_size;
2300        unsigned long deflate_size;
2301        unsigned long data_size;
2302
2303        /* We could do deflated delta, or we could do just deflated two,
2304         * whichever is smaller.
2305         */
2306        delta = NULL;
2307        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2308        if (one->size && two->size) {
2309                delta = diff_delta(one->ptr, one->size,
2310                                   two->ptr, two->size,
2311                                   &delta_size, deflate_size);
2312                if (delta) {
2313                        void *to_free = delta;
2314                        orig_size = delta_size;
2315                        delta = deflate_it(delta, delta_size, &delta_size);
2316                        free(to_free);
2317                }
2318        }
2319
2320        if (delta && delta_size < deflate_size) {
2321                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2322                free(deflated);
2323                data = delta;
2324                data_size = delta_size;
2325        }
2326        else {
2327                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2328                free(delta);
2329                data = deflated;
2330                data_size = deflate_size;
2331        }
2332
2333        /* emit data encoded in base85 */
2334        cp = data;
2335        while (data_size) {
2336                int bytes = (52 < data_size) ? 52 : data_size;
2337                char line[70];
2338                data_size -= bytes;
2339                if (bytes <= 26)
2340                        line[0] = bytes + 'A' - 1;
2341                else
2342                        line[0] = bytes - 26 + 'a' - 1;
2343                encode_85(line + 1, cp, bytes);
2344                cp = (char *) cp + bytes;
2345                fprintf(file, "%s", prefix);
2346                fputs(line, file);
2347                fputc('\n', file);
2348        }
2349        fprintf(file, "%s\n", prefix);
2350        free(data);
2351}
2352
2353static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2354                             const char *prefix)
2355{
2356        fprintf(file, "%sGIT binary patch\n", prefix);
2357        emit_binary_diff_body(file, one, two, prefix);
2358        emit_binary_diff_body(file, two, one, prefix);
2359}
2360
2361int diff_filespec_is_binary(struct diff_filespec *one)
2362{
2363        if (one->is_binary == -1) {
2364                diff_filespec_load_driver(one);
2365                if (one->driver->binary != -1)
2366                        one->is_binary = one->driver->binary;
2367                else {
2368                        if (!one->data && DIFF_FILE_VALID(one))
2369                                diff_populate_filespec(one, CHECK_BINARY);
2370                        if (one->is_binary == -1 && one->data)
2371                                one->is_binary = buffer_is_binary(one->data,
2372                                                one->size);
2373                        if (one->is_binary == -1)
2374                                one->is_binary = 0;
2375                }
2376        }
2377        return one->is_binary;
2378}
2379
2380static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2381{
2382        diff_filespec_load_driver(one);
2383        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2384}
2385
2386void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2387{
2388        if (!options->a_prefix)
2389                options->a_prefix = a;
2390        if (!options->b_prefix)
2391                options->b_prefix = b;
2392}
2393
2394struct userdiff_driver *get_textconv(struct diff_filespec *one)
2395{
2396        if (!DIFF_FILE_VALID(one))
2397                return NULL;
2398
2399        diff_filespec_load_driver(one);
2400        return userdiff_get_textconv(one->driver);
2401}
2402
2403static void builtin_diff(const char *name_a,
2404                         const char *name_b,
2405                         struct diff_filespec *one,
2406                         struct diff_filespec *two,
2407                         const char *xfrm_msg,
2408                         int must_show_header,
2409                         struct diff_options *o,
2410                         int complete_rewrite)
2411{
2412        mmfile_t mf1, mf2;
2413        const char *lbl[2];
2414        char *a_one, *b_two;
2415        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2416        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2417        const char *a_prefix, *b_prefix;
2418        struct userdiff_driver *textconv_one = NULL;
2419        struct userdiff_driver *textconv_two = NULL;
2420        struct strbuf header = STRBUF_INIT;
2421        const char *line_prefix = diff_line_prefix(o);
2422
2423        diff_set_mnemonic_prefix(o, "a/", "b/");
2424        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2425                a_prefix = o->b_prefix;
2426                b_prefix = o->a_prefix;
2427        } else {
2428                a_prefix = o->a_prefix;
2429                b_prefix = o->b_prefix;
2430        }
2431
2432        if (o->submodule_format == DIFF_SUBMODULE_LOG &&
2433            (!one->mode || S_ISGITLINK(one->mode)) &&
2434            (!two->mode || S_ISGITLINK(two->mode))) {
2435                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2436                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2437                show_submodule_summary(o->file, one->path ? one->path : two->path,
2438                                line_prefix,
2439                                &one->oid, &two->oid,
2440                                two->dirty_submodule,
2441                                meta, del, add, reset);
2442                return;
2443        } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
2444                   (!one->mode || S_ISGITLINK(one->mode)) &&
2445                   (!two->mode || S_ISGITLINK(two->mode))) {
2446                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2447                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2448                show_submodule_inline_diff(o->file, one->path ? one->path : two->path,
2449                                line_prefix,
2450                                &one->oid, &two->oid,
2451                                two->dirty_submodule,
2452                                meta, del, add, reset, o);
2453                return;
2454        }
2455
2456        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2457                textconv_one = get_textconv(one);
2458                textconv_two = get_textconv(two);
2459        }
2460
2461        /* Never use a non-valid filename anywhere if at all possible */
2462        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2463        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2464
2465        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2466        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2467        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2468        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2469        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2470        if (lbl[0][0] == '/') {
2471                /* /dev/null */
2472                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2473                if (xfrm_msg)
2474                        strbuf_addstr(&header, xfrm_msg);
2475                must_show_header = 1;
2476        }
2477        else if (lbl[1][0] == '/') {
2478                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2479                if (xfrm_msg)
2480                        strbuf_addstr(&header, xfrm_msg);
2481                must_show_header = 1;
2482        }
2483        else {
2484                if (one->mode != two->mode) {
2485                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2486                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2487                        must_show_header = 1;
2488                }
2489                if (xfrm_msg)
2490                        strbuf_addstr(&header, xfrm_msg);
2491
2492                /*
2493                 * we do not run diff between different kind
2494                 * of objects.
2495                 */
2496                if ((one->mode ^ two->mode) & S_IFMT)
2497                        goto free_ab_and_return;
2498                if (complete_rewrite &&
2499                    (textconv_one || !diff_filespec_is_binary(one)) &&
2500                    (textconv_two || !diff_filespec_is_binary(two))) {
2501                        fprintf(o->file, "%s", header.buf);
2502                        strbuf_reset(&header);
2503                        emit_rewrite_diff(name_a, name_b, one, two,
2504                                                textconv_one, textconv_two, o);
2505                        o->found_changes = 1;
2506                        goto free_ab_and_return;
2507                }
2508        }
2509
2510        if (o->irreversible_delete && lbl[1][0] == '/') {
2511                fprintf(o->file, "%s", header.buf);
2512                strbuf_reset(&header);
2513                goto free_ab_and_return;
2514        } else if (!DIFF_OPT_TST(o, TEXT) &&
2515            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2516              (!textconv_two && diff_filespec_is_binary(two)) )) {
2517                if (!one->data && !two->data &&
2518                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2519                    !DIFF_OPT_TST(o, BINARY)) {
2520                        if (!oidcmp(&one->oid, &two->oid)) {
2521                                if (must_show_header)
2522                                        fprintf(o->file, "%s", header.buf);
2523                                goto free_ab_and_return;
2524                        }
2525                        fprintf(o->file, "%s", header.buf);
2526                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2527                                line_prefix, lbl[0], lbl[1]);
2528                        goto free_ab_and_return;
2529                }
2530                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2531                        die("unable to read files to diff");
2532                /* Quite common confusing case */
2533                if (mf1.size == mf2.size &&
2534                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2535                        if (must_show_header)
2536                                fprintf(o->file, "%s", header.buf);
2537                        goto free_ab_and_return;
2538                }
2539                fprintf(o->file, "%s", header.buf);
2540                strbuf_reset(&header);
2541                if (DIFF_OPT_TST(o, BINARY))
2542                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2543                else
2544                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2545                                line_prefix, lbl[0], lbl[1]);
2546                o->found_changes = 1;
2547        } else {
2548                /* Crazy xdl interfaces.. */
2549                const char *diffopts = getenv("GIT_DIFF_OPTS");
2550                const char *v;
2551                xpparam_t xpp;
2552                xdemitconf_t xecfg;
2553                struct emit_callback ecbdata;
2554                const struct userdiff_funcname *pe;
2555
2556                if (must_show_header) {
2557                        fprintf(o->file, "%s", header.buf);
2558                        strbuf_reset(&header);
2559                }
2560
2561                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2562                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2563
2564                pe = diff_funcname_pattern(one);
2565                if (!pe)
2566                        pe = diff_funcname_pattern(two);
2567
2568                memset(&xpp, 0, sizeof(xpp));
2569                memset(&xecfg, 0, sizeof(xecfg));
2570                memset(&ecbdata, 0, sizeof(ecbdata));
2571                ecbdata.label_path = lbl;
2572                ecbdata.color_diff = want_color(o->use_color);
2573                ecbdata.ws_rule = whitespace_rule(name_b);
2574                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2575                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2576                ecbdata.opt = o;
2577                ecbdata.header = header.len ? &header : NULL;
2578                xpp.flags = o->xdl_opts;
2579                xecfg.ctxlen = o->context;
2580                xecfg.interhunkctxlen = o->interhunkcontext;
2581                xecfg.flags = XDL_EMIT_FUNCNAMES;
2582                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2583                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2584                if (pe)
2585                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2586                if (!diffopts)
2587                        ;
2588                else if (skip_prefix(diffopts, "--unified=", &v))
2589                        xecfg.ctxlen = strtoul(v, NULL, 10);
2590                else if (skip_prefix(diffopts, "-u", &v))
2591                        xecfg.ctxlen = strtoul(v, NULL, 10);
2592                if (o->word_diff)
2593                        init_diff_words_data(&ecbdata, o, one, two);
2594                if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2595                                  &xpp, &xecfg))
2596                        die("unable to generate diff for %s", one->path);
2597                if (o->word_diff)
2598                        free_diff_words_data(&ecbdata);
2599                if (textconv_one)
2600                        free(mf1.ptr);
2601                if (textconv_two)
2602                        free(mf2.ptr);
2603                xdiff_clear_find_func(&xecfg);
2604        }
2605
2606 free_ab_and_return:
2607        strbuf_release(&header);
2608        diff_free_filespec_data(one);
2609        diff_free_filespec_data(two);
2610        free(a_one);
2611        free(b_two);
2612        return;
2613}
2614
2615static void builtin_diffstat(const char *name_a, const char *name_b,
2616                             struct diff_filespec *one,
2617                             struct diff_filespec *two,
2618                             struct diffstat_t *diffstat,
2619                             struct diff_options *o,
2620                             struct diff_filepair *p)
2621{
2622        mmfile_t mf1, mf2;
2623        struct diffstat_file *data;
2624        int same_contents;
2625        int complete_rewrite = 0;
2626
2627        if (!DIFF_PAIR_UNMERGED(p)) {
2628                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2629                        complete_rewrite = 1;
2630        }
2631
2632        data = diffstat_add(diffstat, name_a, name_b);
2633        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2634
2635        if (!one || !two) {
2636                data->is_unmerged = 1;
2637                return;
2638        }
2639
2640        same_contents = !oidcmp(&one->oid, &two->oid);
2641
2642        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2643                data->is_binary = 1;
2644                if (same_contents) {
2645                        data->added = 0;
2646                        data->deleted = 0;
2647                } else {
2648                        data->added = diff_filespec_size(two);
2649                        data->deleted = diff_filespec_size(one);
2650                }
2651        }
2652
2653        else if (complete_rewrite) {
2654                diff_populate_filespec(one, 0);
2655                diff_populate_filespec(two, 0);
2656                data->deleted = count_lines(one->data, one->size);
2657                data->added = count_lines(two->data, two->size);
2658        }
2659
2660        else if (!same_contents) {
2661                /* Crazy xdl interfaces.. */
2662                xpparam_t xpp;
2663                xdemitconf_t xecfg;
2664
2665                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2666                        die("unable to read files to diff");
2667
2668                memset(&xpp, 0, sizeof(xpp));
2669                memset(&xecfg, 0, sizeof(xecfg));
2670                xpp.flags = o->xdl_opts;
2671                xecfg.ctxlen = o->context;
2672                xecfg.interhunkctxlen = o->interhunkcontext;
2673                if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2674                                  &xpp, &xecfg))
2675                        die("unable to generate diffstat for %s", one->path);
2676        }
2677
2678        diff_free_filespec_data(one);
2679        diff_free_filespec_data(two);
2680}
2681
2682static void builtin_checkdiff(const char *name_a, const char *name_b,
2683                              const char *attr_path,
2684                              struct diff_filespec *one,
2685                              struct diff_filespec *two,
2686                              struct diff_options *o)
2687{
2688        mmfile_t mf1, mf2;
2689        struct checkdiff_t data;
2690
2691        if (!two)
2692                return;
2693
2694        memset(&data, 0, sizeof(data));
2695        data.filename = name_b ? name_b : name_a;
2696        data.lineno = 0;
2697        data.o = o;
2698        data.ws_rule = whitespace_rule(attr_path);
2699        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2700
2701        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2702                die("unable to read files to diff");
2703
2704        /*
2705         * All the other codepaths check both sides, but not checking
2706         * the "old" side here is deliberate.  We are checking the newly
2707         * introduced changes, and as long as the "new" side is text, we
2708         * can and should check what it introduces.
2709         */
2710        if (diff_filespec_is_binary(two))
2711                goto free_and_return;
2712        else {
2713                /* Crazy xdl interfaces.. */
2714                xpparam_t xpp;
2715                xdemitconf_t xecfg;
2716
2717                memset(&xpp, 0, sizeof(xpp));
2718                memset(&xecfg, 0, sizeof(xecfg));
2719                xecfg.ctxlen = 1; /* at least one context line */
2720                xpp.flags = 0;
2721                if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2722                                  &xpp, &xecfg))
2723                        die("unable to generate checkdiff for %s", one->path);
2724
2725                if (data.ws_rule & WS_BLANK_AT_EOF) {
2726                        struct emit_callback ecbdata;
2727                        int blank_at_eof;
2728
2729                        ecbdata.ws_rule = data.ws_rule;
2730                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2731                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2732
2733                        if (blank_at_eof) {
2734                                static char *err;
2735                                if (!err)
2736                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2737                                fprintf(o->file, "%s:%d: %s.\n",
2738                                        data.filename, blank_at_eof, err);
2739                                data.status = 1; /* report errors */
2740                        }
2741                }
2742        }
2743 free_and_return:
2744        diff_free_filespec_data(one);
2745        diff_free_filespec_data(two);
2746        if (data.status)
2747                DIFF_OPT_SET(o, CHECK_FAILED);
2748}
2749
2750struct diff_filespec *alloc_filespec(const char *path)
2751{
2752        struct diff_filespec *spec;
2753
2754        FLEXPTR_ALLOC_STR(spec, path, path);
2755        spec->count = 1;
2756        spec->is_binary = -1;
2757        return spec;
2758}
2759
2760void free_filespec(struct diff_filespec *spec)
2761{
2762        if (!--spec->count) {
2763                diff_free_filespec_data(spec);
2764                free(spec);
2765        }
2766}
2767
2768void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
2769                   int oid_valid, unsigned short mode)
2770{
2771        if (mode) {
2772                spec->mode = canon_mode(mode);
2773                oidcpy(&spec->oid, oid);
2774                spec->oid_valid = oid_valid;
2775        }
2776}
2777
2778/*
2779 * Given a name and sha1 pair, if the index tells us the file in
2780 * the work tree has that object contents, return true, so that
2781 * prepare_temp_file() does not have to inflate and extract.
2782 */
2783static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
2784{
2785        const struct cache_entry *ce;
2786        struct stat st;
2787        int pos, len;
2788
2789        /*
2790         * We do not read the cache ourselves here, because the
2791         * benchmark with my previous version that always reads cache
2792         * shows that it makes things worse for diff-tree comparing
2793         * two linux-2.6 kernel trees in an already checked out work
2794         * tree.  This is because most diff-tree comparisons deal with
2795         * only a small number of files, while reading the cache is
2796         * expensive for a large project, and its cost outweighs the
2797         * savings we get by not inflating the object to a temporary
2798         * file.  Practically, this code only helps when we are used
2799         * by diff-cache --cached, which does read the cache before
2800         * calling us.
2801         */
2802        if (!active_cache)
2803                return 0;
2804
2805        /* We want to avoid the working directory if our caller
2806         * doesn't need the data in a normal file, this system
2807         * is rather slow with its stat/open/mmap/close syscalls,
2808         * and the object is contained in a pack file.  The pack
2809         * is probably already open and will be faster to obtain
2810         * the data through than the working directory.  Loose
2811         * objects however would tend to be slower as they need
2812         * to be individually opened and inflated.
2813         */
2814        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(oid->hash))
2815                return 0;
2816
2817        /*
2818         * Similarly, if we'd have to convert the file contents anyway, that
2819         * makes the optimization not worthwhile.
2820         */
2821        if (!want_file && would_convert_to_git(&the_index, name))
2822                return 0;
2823
2824        len = strlen(name);
2825        pos = cache_name_pos(name, len);
2826        if (pos < 0)
2827                return 0;
2828        ce = active_cache[pos];
2829
2830        /*
2831         * This is not the sha1 we are looking for, or
2832         * unreusable because it is not a regular file.
2833         */
2834        if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
2835                return 0;
2836
2837        /*
2838         * If ce is marked as "assume unchanged", there is no
2839         * guarantee that work tree matches what we are looking for.
2840         */
2841        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2842                return 0;
2843
2844        /*
2845         * If ce matches the file in the work tree, we can reuse it.
2846         */
2847        if (ce_uptodate(ce) ||
2848            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2849                return 1;
2850
2851        return 0;
2852}
2853
2854static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2855{
2856        struct strbuf buf = STRBUF_INIT;
2857        char *dirty = "";
2858
2859        /* Are we looking at the work tree? */
2860        if (s->dirty_submodule)
2861                dirty = "-dirty";
2862
2863        strbuf_addf(&buf, "Subproject commit %s%s\n",
2864                    oid_to_hex(&s->oid), dirty);
2865        s->size = buf.len;
2866        if (size_only) {
2867                s->data = NULL;
2868                strbuf_release(&buf);
2869        } else {
2870                s->data = strbuf_detach(&buf, NULL);
2871                s->should_free = 1;
2872        }
2873        return 0;
2874}
2875
2876/*
2877 * While doing rename detection and pickaxe operation, we may need to
2878 * grab the data for the blob (or file) for our own in-core comparison.
2879 * diff_filespec has data and size fields for this purpose.
2880 */
2881int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2882{
2883        int size_only = flags & CHECK_SIZE_ONLY;
2884        int err = 0;
2885        /*
2886         * demote FAIL to WARN to allow inspecting the situation
2887         * instead of refusing.
2888         */
2889        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2890                                    ? SAFE_CRLF_WARN
2891                                    : safe_crlf);
2892
2893        if (!DIFF_FILE_VALID(s))
2894                die("internal error: asking to populate invalid file.");
2895        if (S_ISDIR(s->mode))
2896                return -1;
2897
2898        if (s->data)
2899                return 0;
2900
2901        if (size_only && 0 < s->size)
2902                return 0;
2903
2904        if (S_ISGITLINK(s->mode))
2905                return diff_populate_gitlink(s, size_only);
2906
2907        if (!s->oid_valid ||
2908            reuse_worktree_file(s->path, &s->oid, 0)) {
2909                struct strbuf buf = STRBUF_INIT;
2910                struct stat st;
2911                int fd;
2912
2913                if (lstat(s->path, &st) < 0) {
2914                        if (errno == ENOENT) {
2915                        err_empty:
2916                                err = -1;
2917                        empty:
2918                                s->data = (char *)"";
2919                                s->size = 0;
2920                                return err;
2921                        }
2922                }
2923                s->size = xsize_t(st.st_size);
2924                if (!s->size)
2925                        goto empty;
2926                if (S_ISLNK(st.st_mode)) {
2927                        struct strbuf sb = STRBUF_INIT;
2928
2929                        if (strbuf_readlink(&sb, s->path, s->size))
2930                                goto err_empty;
2931                        s->size = sb.len;
2932                        s->data = strbuf_detach(&sb, NULL);
2933                        s->should_free = 1;
2934                        return 0;
2935                }
2936
2937                /*
2938                 * Even if the caller would be happy with getting
2939                 * only the size, we cannot return early at this
2940                 * point if the path requires us to run the content
2941                 * conversion.
2942                 */
2943                if (size_only && !would_convert_to_git(&the_index, s->path))
2944                        return 0;
2945
2946                /*
2947                 * Note: this check uses xsize_t(st.st_size) that may
2948                 * not be the true size of the blob after it goes
2949                 * through convert_to_git().  This may not strictly be
2950                 * correct, but the whole point of big_file_threshold
2951                 * and is_binary check being that we want to avoid
2952                 * opening the file and inspecting the contents, this
2953                 * is probably fine.
2954                 */
2955                if ((flags & CHECK_BINARY) &&
2956                    s->size > big_file_threshold && s->is_binary == -1) {
2957                        s->is_binary = 1;
2958                        return 0;
2959                }
2960                fd = open(s->path, O_RDONLY);
2961                if (fd < 0)
2962                        goto err_empty;
2963                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2964                close(fd);
2965                s->should_munmap = 1;
2966
2967                /*
2968                 * Convert from working tree format to canonical git format
2969                 */
2970                if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, crlf_warn)) {
2971                        size_t size = 0;
2972                        munmap(s->data, s->size);
2973                        s->should_munmap = 0;
2974                        s->data = strbuf_detach(&buf, &size);
2975                        s->size = size;
2976                        s->should_free = 1;
2977                }
2978        }
2979        else {
2980                enum object_type type;
2981                if (size_only || (flags & CHECK_BINARY)) {
2982                        type = sha1_object_info(s->oid.hash, &s->size);
2983                        if (type < 0)
2984                                die("unable to read %s",
2985                                    oid_to_hex(&s->oid));
2986                        if (size_only)
2987                                return 0;
2988                        if (s->size > big_file_threshold && s->is_binary == -1) {
2989                                s->is_binary = 1;
2990                                return 0;
2991                        }
2992                }
2993                s->data = read_sha1_file(s->oid.hash, &type, &s->size);
2994                if (!s->data)
2995                        die("unable to read %s", oid_to_hex(&s->oid));
2996                s->should_free = 1;
2997        }
2998        return 0;
2999}
3000
3001void diff_free_filespec_blob(struct diff_filespec *s)
3002{
3003        if (s->should_free)
3004                free(s->data);
3005        else if (s->should_munmap)
3006                munmap(s->data, s->size);
3007
3008        if (s->should_free || s->should_munmap) {
3009                s->should_free = s->should_munmap = 0;
3010                s->data = NULL;
3011        }
3012}
3013
3014void diff_free_filespec_data(struct diff_filespec *s)
3015{
3016        diff_free_filespec_blob(s);
3017        FREE_AND_NULL(s->cnt_data);
3018}
3019
3020static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
3021                           void *blob,
3022                           unsigned long size,
3023                           const struct object_id *oid,
3024                           int mode)
3025{
3026        int fd;
3027        struct strbuf buf = STRBUF_INIT;
3028        struct strbuf template = STRBUF_INIT;
3029        char *path_dup = xstrdup(path);
3030        const char *base = basename(path_dup);
3031
3032        /* Generate "XXXXXX_basename.ext" */
3033        strbuf_addstr(&template, "XXXXXX_");
3034        strbuf_addstr(&template, base);
3035
3036        fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
3037        if (fd < 0)
3038                die_errno("unable to create temp-file");
3039        if (convert_to_working_tree(path,
3040                        (const char *)blob, (size_t)size, &buf)) {
3041                blob = buf.buf;
3042                size = buf.len;
3043        }
3044        if (write_in_full(fd, blob, size) != size)
3045                die_errno("unable to write temp-file");
3046        close_tempfile(&temp->tempfile);
3047        temp->name = get_tempfile_path(&temp->tempfile);
3048        oid_to_hex_r(temp->hex, oid);
3049        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
3050        strbuf_release(&buf);
3051        strbuf_release(&template);
3052        free(path_dup);
3053}
3054
3055static struct diff_tempfile *prepare_temp_file(const char *name,
3056                struct diff_filespec *one)
3057{
3058        struct diff_tempfile *temp = claim_diff_tempfile();
3059
3060        if (!DIFF_FILE_VALID(one)) {
3061        not_a_valid_file:
3062                /* A '-' entry produces this for file-2, and
3063                 * a '+' entry produces this for file-1.
3064                 */
3065                temp->name = "/dev/null";
3066                xsnprintf(temp->hex, sizeof(temp->hex), ".");
3067                xsnprintf(temp->mode, sizeof(temp->mode), ".");
3068                return temp;
3069        }
3070
3071        if (!S_ISGITLINK(one->mode) &&
3072            (!one->oid_valid ||
3073             reuse_worktree_file(name, &one->oid, 1))) {
3074                struct stat st;
3075                if (lstat(name, &st) < 0) {
3076                        if (errno == ENOENT)
3077                                goto not_a_valid_file;
3078                        die_errno("stat(%s)", name);
3079                }
3080                if (S_ISLNK(st.st_mode)) {
3081                        struct strbuf sb = STRBUF_INIT;
3082                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
3083                                die_errno("readlink(%s)", name);
3084                        prep_temp_blob(name, temp, sb.buf, sb.len,
3085                                       (one->oid_valid ?
3086                                        &one->oid : &null_oid),
3087                                       (one->oid_valid ?
3088                                        one->mode : S_IFLNK));
3089                        strbuf_release(&sb);
3090                }
3091                else {
3092                        /* we can borrow from the file in the work tree */
3093                        temp->name = name;
3094                        if (!one->oid_valid)
3095                                oid_to_hex_r(temp->hex, &null_oid);
3096                        else
3097                                oid_to_hex_r(temp->hex, &one->oid);
3098                        /* Even though we may sometimes borrow the
3099                         * contents from the work tree, we always want
3100                         * one->mode.  mode is trustworthy even when
3101                         * !(one->oid_valid), as long as
3102                         * DIFF_FILE_VALID(one).
3103                         */
3104                        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3105                }
3106                return temp;
3107        }
3108        else {
3109                if (diff_populate_filespec(one, 0))
3110                        die("cannot read data blob for %s", one->path);
3111                prep_temp_blob(name, temp, one->data, one->size,
3112                               &one->oid, one->mode);
3113        }
3114        return temp;
3115}
3116
3117static void add_external_diff_name(struct argv_array *argv,
3118                                   const char *name,
3119                                   struct diff_filespec *df)
3120{
3121        struct diff_tempfile *temp = prepare_temp_file(name, df);
3122        argv_array_push(argv, temp->name);
3123        argv_array_push(argv, temp->hex);
3124        argv_array_push(argv, temp->mode);
3125}
3126
3127/* An external diff command takes:
3128 *
3129 * diff-cmd name infile1 infile1-sha1 infile1-mode \
3130 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3131 *
3132 */
3133static void run_external_diff(const char *pgm,
3134                              const char *name,
3135                              const char *other,
3136                              struct diff_filespec *one,
3137                              struct diff_filespec *two,
3138                              const char *xfrm_msg,
3139                              int complete_rewrite,
3140                              struct diff_options *o)
3141{
3142        struct argv_array argv = ARGV_ARRAY_INIT;
3143        struct argv_array env = ARGV_ARRAY_INIT;
3144        struct diff_queue_struct *q = &diff_queued_diff;
3145
3146        argv_array_push(&argv, pgm);
3147        argv_array_push(&argv, name);
3148
3149        if (one && two) {
3150                add_external_diff_name(&argv, name, one);
3151                if (!other)
3152                        add_external_diff_name(&argv, name, two);
3153                else {
3154                        add_external_diff_name(&argv, other, two);
3155                        argv_array_push(&argv, other);
3156                        argv_array_push(&argv, xfrm_msg);
3157                }
3158        }
3159
3160        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3161        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3162
3163        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3164                die(_("external diff died, stopping at %s"), name);
3165
3166        remove_tempfile();
3167        argv_array_clear(&argv);
3168        argv_array_clear(&env);
3169}
3170
3171static int similarity_index(struct diff_filepair *p)
3172{
3173        return p->score * 100 / MAX_SCORE;
3174}
3175
3176static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3177{
3178        if (startup_info->have_repository)
3179                return find_unique_abbrev(oid->hash, abbrev);
3180        else {
3181                char *hex = oid_to_hex(oid);
3182                if (abbrev < 0)
3183                        abbrev = FALLBACK_DEFAULT_ABBREV;
3184                if (abbrev > GIT_SHA1_HEXSZ)
3185                        die("BUG: oid abbreviation out of range: %d", abbrev);
3186                if (abbrev)
3187                        hex[abbrev] = '\0';
3188                return hex;
3189        }
3190}
3191
3192static void fill_metainfo(struct strbuf *msg,
3193                          const char *name,
3194                          const char *other,
3195                          struct diff_filespec *one,
3196                          struct diff_filespec *two,
3197                          struct diff_options *o,
3198                          struct diff_filepair *p,
3199                          int *must_show_header,
3200                          int use_color)
3201{
3202        const char *set = diff_get_color(use_color, DIFF_METAINFO);
3203        const char *reset = diff_get_color(use_color, DIFF_RESET);
3204        const char *line_prefix = diff_line_prefix(o);
3205
3206        *must_show_header = 1;
3207        strbuf_init(msg, PATH_MAX * 2 + 300);
3208        switch (p->status) {
3209        case DIFF_STATUS_COPIED:
3210                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3211                            line_prefix, set, similarity_index(p));
3212                strbuf_addf(msg, "%s\n%s%scopy from ",
3213                            reset,  line_prefix, set);
3214                quote_c_style(name, msg, NULL, 0);
3215                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3216                quote_c_style(other, msg, NULL, 0);
3217                strbuf_addf(msg, "%s\n", reset);
3218                break;
3219        case DIFF_STATUS_RENAMED:
3220                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3221                            line_prefix, set, similarity_index(p));
3222                strbuf_addf(msg, "%s\n%s%srename from ",
3223                            reset, line_prefix, set);
3224                quote_c_style(name, msg, NULL, 0);
3225                strbuf_addf(msg, "%s\n%s%srename to ",
3226                            reset, line_prefix, set);
3227                quote_c_style(other, msg, NULL, 0);
3228                strbuf_addf(msg, "%s\n", reset);
3229                break;
3230        case DIFF_STATUS_MODIFIED:
3231                if (p->score) {
3232                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3233                                    line_prefix,
3234                                    set, similarity_index(p), reset);
3235                        break;
3236                }
3237                /* fallthru */
3238        default:
3239                *must_show_header = 0;
3240        }
3241        if (one && two && oidcmp(&one->oid, &two->oid)) {
3242                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3243
3244                if (DIFF_OPT_TST(o, BINARY)) {
3245                        mmfile_t mf;
3246                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3247                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3248                                abbrev = 40;
3249                }
3250                strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3251                            diff_abbrev_oid(&one->oid, abbrev),
3252                            diff_abbrev_oid(&two->oid, abbrev));
3253                if (one->mode == two->mode)
3254                        strbuf_addf(msg, " %06o", one->mode);
3255                strbuf_addf(msg, "%s\n", reset);
3256        }
3257}
3258
3259static void run_diff_cmd(const char *pgm,
3260                         const char *name,
3261                         const char *other,
3262                         const char *attr_path,
3263                         struct diff_filespec *one,
3264                         struct diff_filespec *two,
3265                         struct strbuf *msg,
3266                         struct diff_options *o,
3267                         struct diff_filepair *p)
3268{
3269        const char *xfrm_msg = NULL;
3270        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3271        int must_show_header = 0;
3272
3273
3274        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3275                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3276                if (drv && drv->external)
3277                        pgm = drv->external;
3278        }
3279
3280        if (msg) {
3281                /*
3282                 * don't use colors when the header is intended for an
3283                 * external diff driver
3284                 */
3285                fill_metainfo(msg, name, other, one, two, o, p,
3286                              &must_show_header,
3287                              want_color(o->use_color) && !pgm);
3288                xfrm_msg = msg->len ? msg->buf : NULL;
3289        }
3290
3291        if (pgm) {
3292                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3293                                  complete_rewrite, o);
3294                return;
3295        }
3296        if (one && two)
3297                builtin_diff(name, other ? other : name,
3298                             one, two, xfrm_msg, must_show_header,
3299                             o, complete_rewrite);
3300        else
3301                fprintf(o->file, "* Unmerged path %s\n", name);
3302}
3303
3304static void diff_fill_oid_info(struct diff_filespec *one)
3305{
3306        if (DIFF_FILE_VALID(one)) {
3307                if (!one->oid_valid) {
3308                        struct stat st;
3309                        if (one->is_stdin) {
3310                                oidclr(&one->oid);
3311                                return;
3312                        }
3313                        if (lstat(one->path, &st) < 0)
3314                                die_errno("stat '%s'", one->path);
3315                        if (index_path(one->oid.hash, one->path, &st, 0))
3316                                die("cannot hash %s", one->path);
3317                }
3318        }
3319        else
3320                oidclr(&one->oid);
3321}
3322
3323static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3324{
3325        /* Strip the prefix but do not molest /dev/null and absolute paths */
3326        if (*namep && **namep != '/') {
3327                *namep += prefix_length;
3328                if (**namep == '/')
3329                        ++*namep;
3330        }
3331        if (*otherp && **otherp != '/') {
3332                *otherp += prefix_length;
3333                if (**otherp == '/')
3334                        ++*otherp;
3335        }
3336}
3337
3338static void run_diff(struct diff_filepair *p, struct diff_options *o)
3339{
3340        const char *pgm = external_diff();
3341        struct strbuf msg;
3342        struct diff_filespec *one = p->one;
3343        struct diff_filespec *two = p->two;
3344        const char *name;
3345        const char *other;
3346        const char *attr_path;
3347
3348        name  = one->path;
3349        other = (strcmp(name, two->path) ? two->path : NULL);
3350        attr_path = name;
3351        if (o->prefix_length)
3352                strip_prefix(o->prefix_length, &name, &other);
3353
3354        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3355                pgm = NULL;
3356
3357        if (DIFF_PAIR_UNMERGED(p)) {
3358                run_diff_cmd(pgm, name, NULL, attr_path,
3359                             NULL, NULL, NULL, o, p);
3360                return;
3361        }
3362
3363        diff_fill_oid_info(one);
3364        diff_fill_oid_info(two);
3365
3366        if (!pgm &&
3367            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3368            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3369                /*
3370                 * a filepair that changes between file and symlink
3371                 * needs to be split into deletion and creation.
3372                 */
3373                struct diff_filespec *null = alloc_filespec(two->path);
3374                run_diff_cmd(NULL, name, other, attr_path,
3375                             one, null, &msg, o, p);
3376                free(null);
3377                strbuf_release(&msg);
3378
3379                null = alloc_filespec(one->path);
3380                run_diff_cmd(NULL, name, other, attr_path,
3381                             null, two, &msg, o, p);
3382                free(null);
3383        }
3384        else
3385                run_diff_cmd(pgm, name, other, attr_path,
3386                             one, two, &msg, o, p);
3387
3388        strbuf_release(&msg);
3389}
3390
3391static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3392                         struct diffstat_t *diffstat)
3393{
3394        const char *name;
3395        const char *other;
3396
3397        if (DIFF_PAIR_UNMERGED(p)) {
3398                /* unmerged */
3399                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3400                return;
3401        }
3402
3403        name = p->one->path;
3404        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3405
3406        if (o->prefix_length)
3407                strip_prefix(o->prefix_length, &name, &other);
3408
3409        diff_fill_oid_info(p->one);
3410        diff_fill_oid_info(p->two);
3411
3412        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3413}
3414
3415static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3416{
3417        const char *name;
3418        const char *other;
3419        const char *attr_path;
3420
3421        if (DIFF_PAIR_UNMERGED(p)) {
3422                /* unmerged */
3423                return;
3424        }
3425
3426        name = p->one->path;
3427        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3428        attr_path = other ? other : name;
3429
3430        if (o->prefix_length)
3431                strip_prefix(o->prefix_length, &name, &other);
3432
3433        diff_fill_oid_info(p->one);
3434        diff_fill_oid_info(p->two);
3435
3436        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3437}
3438
3439void diff_setup(struct diff_options *options)
3440{
3441        memcpy(options, &default_diff_options, sizeof(*options));
3442
3443        options->file = stdout;
3444
3445        options->abbrev = DEFAULT_ABBREV;
3446        options->line_termination = '\n';
3447        options->break_opt = -1;
3448        options->rename_limit = -1;
3449        options->dirstat_permille = diff_dirstat_permille_default;
3450        options->context = diff_context_default;
3451        options->interhunkcontext = diff_interhunk_context_default;
3452        options->ws_error_highlight = ws_error_highlight_default;
3453        DIFF_OPT_SET(options, RENAME_EMPTY);
3454
3455        /* pathchange left =NULL by default */
3456        options->change = diff_change;
3457        options->add_remove = diff_addremove;
3458        options->use_color = diff_use_color_default;
3459        options->detect_rename = diff_detect_rename_default;
3460        options->xdl_opts |= diff_algorithm;
3461        if (diff_indent_heuristic)
3462                DIFF_XDL_SET(options, INDENT_HEURISTIC);
3463
3464        options->orderfile = diff_order_file_cfg;
3465
3466        if (diff_no_prefix) {
3467                options->a_prefix = options->b_prefix = "";
3468        } else if (!diff_mnemonic_prefix) {
3469                options->a_prefix = "a/";
3470                options->b_prefix = "b/";
3471        }
3472}
3473
3474void diff_setup_done(struct diff_options *options)
3475{
3476        int count = 0;
3477
3478        if (options->set_default)
3479                options->set_default(options);
3480
3481        if (options->output_format & DIFF_FORMAT_NAME)
3482                count++;
3483        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3484                count++;
3485        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3486                count++;
3487        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3488                count++;
3489        if (count > 1)
3490                die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
3491
3492        /*
3493         * Most of the time we can say "there are changes"
3494         * only by checking if there are changed paths, but
3495         * --ignore-whitespace* options force us to look
3496         * inside contents.
3497         */
3498
3499        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3500            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3501            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3502                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3503        else
3504                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3505
3506        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3507                options->detect_rename = DIFF_DETECT_COPY;
3508
3509        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3510                options->prefix = NULL;
3511        if (options->prefix)
3512                options->prefix_length = strlen(options->prefix);
3513        else
3514                options->prefix_length = 0;
3515
3516        if (options->output_format & (DIFF_FORMAT_NAME |
3517                                      DIFF_FORMAT_NAME_STATUS |
3518                                      DIFF_FORMAT_CHECKDIFF |
3519                                      DIFF_FORMAT_NO_OUTPUT))
3520                options->output_format &= ~(DIFF_FORMAT_RAW |
3521                                            DIFF_FORMAT_NUMSTAT |
3522                                            DIFF_FORMAT_DIFFSTAT |
3523                                            DIFF_FORMAT_SHORTSTAT |
3524                                            DIFF_FORMAT_DIRSTAT |
3525                                            DIFF_FORMAT_SUMMARY |
3526                                            DIFF_FORMAT_PATCH);
3527
3528        /*
3529         * These cases always need recursive; we do not drop caller-supplied
3530         * recursive bits for other formats here.
3531         */
3532        if (options->output_format & (DIFF_FORMAT_PATCH |
3533                                      DIFF_FORMAT_NUMSTAT |
3534                                      DIFF_FORMAT_DIFFSTAT |
3535                                      DIFF_FORMAT_SHORTSTAT |
3536                                      DIFF_FORMAT_DIRSTAT |
3537                                      DIFF_FORMAT_SUMMARY |
3538                                      DIFF_FORMAT_CHECKDIFF))
3539                DIFF_OPT_SET(options, RECURSIVE);
3540        /*
3541         * Also pickaxe would not work very well if you do not say recursive
3542         */
3543        if (options->pickaxe)
3544                DIFF_OPT_SET(options, RECURSIVE);
3545        /*
3546         * When patches are generated, submodules diffed against the work tree
3547         * must be checked for dirtiness too so it can be shown in the output
3548         */
3549        if (options->output_format & DIFF_FORMAT_PATCH)
3550                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3551
3552        if (options->detect_rename && options->rename_limit < 0)
3553                options->rename_limit = diff_rename_limit_default;
3554        if (options->setup & DIFF_SETUP_USE_CACHE) {
3555                if (!active_cache)
3556                        /* read-cache does not die even when it fails
3557                         * so it is safe for us to do this here.  Also
3558                         * it does not smudge active_cache or active_nr
3559                         * when it fails, so we do not have to worry about
3560                         * cleaning it up ourselves either.
3561                         */
3562                        read_cache();
3563        }
3564        if (40 < options->abbrev)
3565                options->abbrev = 40; /* full */
3566
3567        /*
3568         * It does not make sense to show the first hit we happened
3569         * to have found.  It does not make sense not to return with
3570         * exit code in such a case either.
3571         */
3572        if (DIFF_OPT_TST(options, QUICK)) {
3573                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3574                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3575        }
3576
3577        options->diff_path_counter = 0;
3578
3579        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3580                die(_("--follow requires exactly one pathspec"));
3581}
3582
3583static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3584{
3585        char c, *eq;
3586        int len;
3587
3588        if (*arg != '-')
3589                return 0;
3590        c = *++arg;
3591        if (!c)
3592                return 0;
3593        if (c == arg_short) {
3594                c = *++arg;
3595                if (!c)
3596                        return 1;
3597                if (val && isdigit(c)) {
3598                        char *end;
3599                        int n = strtoul(arg, &end, 10);
3600                        if (*end)
3601                                return 0;
3602                        *val = n;
3603                        return 1;
3604                }
3605                return 0;
3606        }
3607        if (c != '-')
3608                return 0;
3609        arg++;
3610        eq = strchrnul(arg, '=');
3611        len = eq - arg;
3612        if (!len || strncmp(arg, arg_long, len))
3613                return 0;
3614        if (*eq) {
3615                int n;
3616                char *end;
3617                if (!isdigit(*++eq))
3618                        return 0;
3619                n = strtoul(eq, &end, 10);
3620                if (*end)
3621                        return 0;
3622                *val = n;
3623        }
3624        return 1;
3625}
3626
3627static int diff_scoreopt_parse(const char *opt);
3628
3629static inline int short_opt(char opt, const char **argv,
3630                            const char **optarg)
3631{
3632        const char *arg = argv[0];
3633        if (arg[0] != '-' || arg[1] != opt)
3634                return 0;
3635        if (arg[2] != '\0') {
3636                *optarg = arg + 2;
3637                return 1;
3638        }
3639        if (!argv[1])
3640                die("Option '%c' requires a value", opt);
3641        *optarg = argv[1];
3642        return 2;
3643}
3644
3645int parse_long_opt(const char *opt, const char **argv,
3646                   const char **optarg)
3647{
3648        const char *arg = argv[0];
3649        if (!skip_prefix(arg, "--", &arg))
3650                return 0;
3651        if (!skip_prefix(arg, opt, &arg))
3652                return 0;
3653        if (*arg == '=') { /* stuck form: --option=value */
3654                *optarg = arg + 1;
3655                return 1;
3656        }
3657        if (*arg != '\0')
3658                return 0;
3659        /* separate form: --option value */
3660        if (!argv[1])
3661                die("Option '--%s' requires a value", opt);
3662        *optarg = argv[1];
3663        return 2;
3664}
3665
3666static int stat_opt(struct diff_options *options, const char **av)
3667{
3668        const char *arg = av[0];
3669        char *end;
3670        int width = options->stat_width;
3671        int name_width = options->stat_name_width;
3672        int graph_width = options->stat_graph_width;
3673        int count = options->stat_count;
3674        int argcount = 1;
3675
3676        if (!skip_prefix(arg, "--stat", &arg))
3677                die("BUG: stat option does not begin with --stat: %s", arg);
3678        end = (char *)arg;
3679
3680        switch (*arg) {
3681        case '-':
3682                if (skip_prefix(arg, "-width", &arg)) {
3683                        if (*arg == '=')
3684                                width = strtoul(arg + 1, &end, 10);
3685                        else if (!*arg && !av[1])
3686                                die_want_option("--stat-width");
3687                        else if (!*arg) {
3688                                width = strtoul(av[1], &end, 10);
3689                                argcount = 2;
3690                        }
3691                } else if (skip_prefix(arg, "-name-width", &arg)) {
3692                        if (*arg == '=')
3693                                name_width = strtoul(arg + 1, &end, 10);
3694                        else if (!*arg && !av[1])
3695                                die_want_option("--stat-name-width");
3696                        else if (!*arg) {
3697                                name_width = strtoul(av[1], &end, 10);
3698                                argcount = 2;
3699                        }
3700                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3701                        if (*arg == '=')
3702                                graph_width = strtoul(arg + 1, &end, 10);
3703                        else if (!*arg && !av[1])
3704                                die_want_option("--stat-graph-width");
3705                        else if (!*arg) {
3706                                graph_width = strtoul(av[1], &end, 10);
3707                                argcount = 2;
3708                        }
3709                } else if (skip_prefix(arg, "-count", &arg)) {
3710                        if (*arg == '=')
3711                                count = strtoul(arg + 1, &end, 10);
3712                        else if (!*arg && !av[1])
3713                                die_want_option("--stat-count");
3714                        else if (!*arg) {
3715                                count = strtoul(av[1], &end, 10);
3716                                argcount = 2;
3717                        }
3718                }
3719                break;
3720        case '=':
3721                width = strtoul(arg+1, &end, 10);
3722                if (*end == ',')
3723                        name_width = strtoul(end+1, &end, 10);
3724                if (*end == ',')
3725                        count = strtoul(end+1, &end, 10);
3726        }
3727
3728        /* Important! This checks all the error cases! */
3729        if (*end)
3730                return 0;
3731        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3732        options->stat_name_width = name_width;
3733        options->stat_graph_width = graph_width;
3734        options->stat_width = width;
3735        options->stat_count = count;
3736        return argcount;
3737}
3738
3739static int parse_dirstat_opt(struct diff_options *options, const char *params)
3740{
3741        struct strbuf errmsg = STRBUF_INIT;
3742        if (parse_dirstat_params(options, params, &errmsg))
3743                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3744                    errmsg.buf);
3745        strbuf_release(&errmsg);
3746        /*
3747         * The caller knows a dirstat-related option is given from the command
3748         * line; allow it to say "return this_function();"
3749         */
3750        options->output_format |= DIFF_FORMAT_DIRSTAT;
3751        return 1;
3752}
3753
3754static int parse_submodule_opt(struct diff_options *options, const char *value)
3755{
3756        if (parse_submodule_params(options, value))
3757                die(_("Failed to parse --submodule option parameter: '%s'"),
3758                        value);
3759        return 1;
3760}
3761
3762static const char diff_status_letters[] = {
3763        DIFF_STATUS_ADDED,
3764        DIFF_STATUS_COPIED,
3765        DIFF_STATUS_DELETED,
3766        DIFF_STATUS_MODIFIED,
3767        DIFF_STATUS_RENAMED,
3768        DIFF_STATUS_TYPE_CHANGED,
3769        DIFF_STATUS_UNKNOWN,
3770        DIFF_STATUS_UNMERGED,
3771        DIFF_STATUS_FILTER_AON,
3772        DIFF_STATUS_FILTER_BROKEN,
3773        '\0',
3774};
3775
3776static unsigned int filter_bit['Z' + 1];
3777
3778static void prepare_filter_bits(void)
3779{
3780        int i;
3781
3782        if (!filter_bit[DIFF_STATUS_ADDED]) {
3783                for (i = 0; diff_status_letters[i]; i++)
3784                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3785        }
3786}
3787
3788static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3789{
3790        return opt->filter & filter_bit[(int) status];
3791}
3792
3793static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3794{
3795        int i, optch;
3796
3797        prepare_filter_bits();
3798
3799        /*
3800         * If there is a negation e.g. 'd' in the input, and we haven't
3801         * initialized the filter field with another --diff-filter, start
3802         * from full set of bits, except for AON.
3803         */
3804        if (!opt->filter) {
3805                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3806                        if (optch < 'a' || 'z' < optch)
3807                                continue;
3808                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3809                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3810                        break;
3811                }
3812        }
3813
3814        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3815                unsigned int bit;
3816                int negate;
3817
3818                if ('a' <= optch && optch <= 'z') {
3819                        negate = 1;
3820                        optch = toupper(optch);
3821                } else {
3822                        negate = 0;
3823                }
3824
3825                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3826                if (!bit)
3827                        return optarg[i];
3828                if (negate)
3829                        opt->filter &= ~bit;
3830                else
3831                        opt->filter |= bit;
3832        }
3833        return 0;
3834}
3835
3836static void enable_patch_output(int *fmt) {
3837        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3838        *fmt |= DIFF_FORMAT_PATCH;
3839}
3840
3841static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
3842{
3843        int val = parse_ws_error_highlight(arg);
3844
3845        if (val < 0) {
3846                error("unknown value after ws-error-highlight=%.*s",
3847                      -1 - val, arg);
3848                return 0;
3849        }
3850        opt->ws_error_highlight = val;
3851        return 1;
3852}
3853
3854int diff_opt_parse(struct diff_options *options,
3855                   const char **av, int ac, const char *prefix)
3856{
3857        const char *arg = av[0];
3858        const char *optarg;
3859        int argcount;
3860
3861        if (!prefix)
3862                prefix = "";
3863
3864        /* Output format options */
3865        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3866            || opt_arg(arg, 'U', "unified", &options->context))
3867                enable_patch_output(&options->output_format);
3868        else if (!strcmp(arg, "--raw"))
3869                options->output_format |= DIFF_FORMAT_RAW;
3870        else if (!strcmp(arg, "--patch-with-raw")) {
3871                enable_patch_output(&options->output_format);
3872                options->output_format |= DIFF_FORMAT_RAW;
3873        } else if (!strcmp(arg, "--numstat"))
3874                options->output_format |= DIFF_FORMAT_NUMSTAT;
3875        else if (!strcmp(arg, "--shortstat"))
3876                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3877        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3878                return parse_dirstat_opt(options, "");
3879        else if (skip_prefix(arg, "-X", &arg))
3880                return parse_dirstat_opt(options, arg);
3881        else if (skip_prefix(arg, "--dirstat=", &arg))
3882                return parse_dirstat_opt(options, arg);
3883        else if (!strcmp(arg, "--cumulative"))
3884                return parse_dirstat_opt(options, "cumulative");
3885        else if (!strcmp(arg, "--dirstat-by-file"))
3886                return parse_dirstat_opt(options, "files");
3887        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3888                parse_dirstat_opt(options, "files");
3889                return parse_dirstat_opt(options, arg);
3890        }
3891        else if (!strcmp(arg, "--check"))
3892                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3893        else if (!strcmp(arg, "--summary"))
3894                options->output_format |= DIFF_FORMAT_SUMMARY;
3895        else if (!strcmp(arg, "--patch-with-stat")) {
3896                enable_patch_output(&options->output_format);
3897                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3898        } else if (!strcmp(arg, "--name-only"))
3899                options->output_format |= DIFF_FORMAT_NAME;
3900        else if (!strcmp(arg, "--name-status"))
3901                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3902        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3903                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3904        else if (starts_with(arg, "--stat"))
3905                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3906                return stat_opt(options, av);
3907
3908        /* renames options */
3909        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3910                 !strcmp(arg, "--break-rewrites")) {
3911                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3912                        return error("invalid argument to -B: %s", arg+2);
3913        }
3914        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3915                 !strcmp(arg, "--find-renames")) {
3916                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3917                        return error("invalid argument to -M: %s", arg+2);
3918                options->detect_rename = DIFF_DETECT_RENAME;
3919        }
3920        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3921                options->irreversible_delete = 1;
3922        }
3923        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3924                 !strcmp(arg, "--find-copies")) {
3925                if (options->detect_rename == DIFF_DETECT_COPY)
3926                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3927                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3928                        return error("invalid argument to -C: %s", arg+2);
3929                options->detect_rename = DIFF_DETECT_COPY;
3930        }
3931        else if (!strcmp(arg, "--no-renames"))
3932                options->detect_rename = 0;
3933        else if (!strcmp(arg, "--rename-empty"))
3934                DIFF_OPT_SET(options, RENAME_EMPTY);
3935        else if (!strcmp(arg, "--no-rename-empty"))
3936                DIFF_OPT_CLR(options, RENAME_EMPTY);
3937        else if (!strcmp(arg, "--relative"))
3938                DIFF_OPT_SET(options, RELATIVE_NAME);
3939        else if (skip_prefix(arg, "--relative=", &arg)) {
3940                DIFF_OPT_SET(options, RELATIVE_NAME);
3941                options->prefix = arg;
3942        }
3943
3944        /* xdiff options */
3945        else if (!strcmp(arg, "--minimal"))
3946                DIFF_XDL_SET(options, NEED_MINIMAL);
3947        else if (!strcmp(arg, "--no-minimal"))
3948                DIFF_XDL_CLR(options, NEED_MINIMAL);
3949        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3950                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3951        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3952                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3953        else if (!strcmp(arg, "--ignore-space-at-eol"))
3954                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3955        else if (!strcmp(arg, "--ignore-blank-lines"))
3956                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3957        else if (!strcmp(arg, "--indent-heuristic"))
3958                DIFF_XDL_SET(options, INDENT_HEURISTIC);
3959        else if (!strcmp(arg, "--no-indent-heuristic"))
3960                DIFF_XDL_CLR(options, INDENT_HEURISTIC);
3961        else if (!strcmp(arg, "--patience"))
3962                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3963        else if (!strcmp(arg, "--histogram"))
3964                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3965        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3966                long value = parse_algorithm_value(optarg);
3967                if (value < 0)
3968                        return error("option diff-algorithm accepts \"myers\", "
3969                                     "\"minimal\", \"patience\" and \"histogram\"");
3970                /* clear out previous settings */
3971                DIFF_XDL_CLR(options, NEED_MINIMAL);
3972                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3973                options->xdl_opts |= value;
3974                return argcount;
3975        }
3976
3977        /* flags options */
3978        else if (!strcmp(arg, "--binary")) {
3979                enable_patch_output(&options->output_format);
3980                DIFF_OPT_SET(options, BINARY);
3981        }
3982        else if (!strcmp(arg, "--full-index"))
3983                DIFF_OPT_SET(options, FULL_INDEX);
3984        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3985                DIFF_OPT_SET(options, TEXT);
3986        else if (!strcmp(arg, "-R"))
3987                DIFF_OPT_SET(options, REVERSE_DIFF);
3988        else if (!strcmp(arg, "--find-copies-harder"))
3989                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3990        else if (!strcmp(arg, "--follow"))
3991                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3992        else if (!strcmp(arg, "--no-follow")) {
3993                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3994                DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
3995        } else if (!strcmp(arg, "--color"))
3996                options->use_color = 1;
3997        else if (skip_prefix(arg, "--color=", &arg)) {
3998                int value = git_config_colorbool(NULL, arg);
3999                if (value < 0)
4000                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
4001                options->use_color = value;
4002        }
4003        else if (!strcmp(arg, "--no-color"))
4004                options->use_color = 0;
4005        else if (!strcmp(arg, "--color-words")) {
4006                options->use_color = 1;
4007                options->word_diff = DIFF_WORDS_COLOR;
4008        }
4009        else if (skip_prefix(arg, "--color-words=", &arg)) {
4010                options->use_color = 1;
4011                options->word_diff = DIFF_WORDS_COLOR;
4012                options->word_regex = arg;
4013        }
4014        else if (!strcmp(arg, "--word-diff")) {
4015                if (options->word_diff == DIFF_WORDS_NONE)
4016                        options->word_diff = DIFF_WORDS_PLAIN;
4017        }
4018        else if (skip_prefix(arg, "--word-diff=", &arg)) {
4019                if (!strcmp(arg, "plain"))
4020                        options->word_diff = DIFF_WORDS_PLAIN;
4021                else if (!strcmp(arg, "color")) {
4022                        options->use_color = 1;
4023                        options->word_diff = DIFF_WORDS_COLOR;
4024                }
4025                else if (!strcmp(arg, "porcelain"))
4026                        options->word_diff = DIFF_WORDS_PORCELAIN;
4027                else if (!strcmp(arg, "none"))
4028                        options->word_diff = DIFF_WORDS_NONE;
4029                else
4030                        die("bad --word-diff argument: %s", arg);
4031        }
4032        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
4033                if (options->word_diff == DIFF_WORDS_NONE)
4034                        options->word_diff = DIFF_WORDS_PLAIN;
4035                options->word_regex = optarg;
4036                return argcount;
4037        }
4038        else if (!strcmp(arg, "--exit-code"))
4039                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
4040        else if (!strcmp(arg, "--quiet"))
4041                DIFF_OPT_SET(options, QUICK);
4042        else if (!strcmp(arg, "--ext-diff"))
4043                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
4044        else if (!strcmp(arg, "--no-ext-diff"))
4045                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
4046        else if (!strcmp(arg, "--textconv"))
4047                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
4048        else if (!strcmp(arg, "--no-textconv"))
4049                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
4050        else if (!strcmp(arg, "--ignore-submodules")) {
4051                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4052                handle_ignore_submodules_arg(options, "all");
4053        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
4054                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4055                handle_ignore_submodules_arg(options, arg);
4056        } else if (!strcmp(arg, "--submodule"))
4057                options->submodule_format = DIFF_SUBMODULE_LOG;
4058        else if (skip_prefix(arg, "--submodule=", &arg))
4059                return parse_submodule_opt(options, arg);
4060        else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
4061                return parse_ws_error_highlight_opt(options, arg);
4062        else if (!strcmp(arg, "--ita-invisible-in-index"))
4063                options->ita_invisible_in_index = 1;
4064        else if (!strcmp(arg, "--ita-visible-in-index"))
4065                options->ita_invisible_in_index = 0;
4066
4067        /* misc options */
4068        else if (!strcmp(arg, "-z"))
4069                options->line_termination = 0;
4070        else if ((argcount = short_opt('l', av, &optarg))) {
4071                options->rename_limit = strtoul(optarg, NULL, 10);
4072                return argcount;
4073        }
4074        else if ((argcount = short_opt('S', av, &optarg))) {
4075                options->pickaxe = optarg;
4076                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4077                return argcount;
4078        } else if ((argcount = short_opt('G', av, &optarg))) {
4079                options->pickaxe = optarg;
4080                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4081                return argcount;
4082        }
4083        else if (!strcmp(arg, "--pickaxe-all"))
4084                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4085        else if (!strcmp(arg, "--pickaxe-regex"))
4086                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4087        else if ((argcount = short_opt('O', av, &optarg))) {
4088                options->orderfile = prefix_filename(prefix, optarg);
4089                return argcount;
4090        }
4091        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4092                int offending = parse_diff_filter_opt(optarg, options);
4093                if (offending)
4094                        die("unknown change class '%c' in --diff-filter=%s",
4095                            offending, optarg);
4096                return argcount;
4097        }
4098        else if (!strcmp(arg, "--no-abbrev"))
4099                options->abbrev = 0;
4100        else if (!strcmp(arg, "--abbrev"))
4101                options->abbrev = DEFAULT_ABBREV;
4102        else if (skip_prefix(arg, "--abbrev=", &arg)) {
4103                options->abbrev = strtoul(arg, NULL, 10);
4104                if (options->abbrev < MINIMUM_ABBREV)
4105                        options->abbrev = MINIMUM_ABBREV;
4106                else if (40 < options->abbrev)
4107                        options->abbrev = 40;
4108        }
4109        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4110                options->a_prefix = optarg;
4111                return argcount;
4112        }
4113        else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4114                options->line_prefix = optarg;
4115                options->line_prefix_length = strlen(options->line_prefix);
4116                graph_setup_line_prefix(options);
4117                return argcount;
4118        }
4119        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4120                options->b_prefix = optarg;
4121                return argcount;
4122        }
4123        else if (!strcmp(arg, "--no-prefix"))
4124                options->a_prefix = options->b_prefix = "";
4125        else if (opt_arg(arg, '\0', "inter-hunk-context",
4126                         &options->interhunkcontext))
4127                ;
4128        else if (!strcmp(arg, "-W"))
4129                DIFF_OPT_SET(options, FUNCCONTEXT);
4130        else if (!strcmp(arg, "--function-context"))
4131                DIFF_OPT_SET(options, FUNCCONTEXT);
4132        else if (!strcmp(arg, "--no-function-context"))
4133                DIFF_OPT_CLR(options, FUNCCONTEXT);
4134        else if ((argcount = parse_long_opt("output", av, &optarg))) {
4135                char *path = prefix_filename(prefix, optarg);
4136                options->file = xfopen(path, "w");
4137                options->close_file = 1;
4138                if (options->use_color != GIT_COLOR_ALWAYS)
4139                        options->use_color = GIT_COLOR_NEVER;
4140                free(path);
4141                return argcount;
4142        } else
4143                return 0;
4144        return 1;
4145}
4146
4147int parse_rename_score(const char **cp_p)
4148{
4149        unsigned long num, scale;
4150        int ch, dot;
4151        const char *cp = *cp_p;
4152
4153        num = 0;
4154        scale = 1;
4155        dot = 0;
4156        for (;;) {
4157                ch = *cp;
4158                if ( !dot && ch == '.' ) {
4159                        scale = 1;
4160                        dot = 1;
4161                } else if ( ch == '%' ) {
4162                        scale = dot ? scale*100 : 100;
4163                        cp++;   /* % is always at the end */
4164                        break;
4165                } else if ( ch >= '0' && ch <= '9' ) {
4166                        if ( scale < 100000 ) {
4167                                scale *= 10;
4168                                num = (num*10) + (ch-'0');
4169                        }
4170                } else {
4171                        break;
4172                }
4173                cp++;
4174        }
4175        *cp_p = cp;
4176
4177        /* user says num divided by scale and we say internally that
4178         * is MAX_SCORE * num / scale.
4179         */
4180        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4181}
4182
4183static int diff_scoreopt_parse(const char *opt)
4184{
4185        int opt1, opt2, cmd;
4186
4187        if (*opt++ != '-')
4188                return -1;
4189        cmd = *opt++;
4190        if (cmd == '-') {
4191                /* convert the long-form arguments into short-form versions */
4192                if (skip_prefix(opt, "break-rewrites", &opt)) {
4193                        if (*opt == 0 || *opt++ == '=')
4194                                cmd = 'B';
4195                } else if (skip_prefix(opt, "find-copies", &opt)) {
4196                        if (*opt == 0 || *opt++ == '=')
4197                                cmd = 'C';
4198                } else if (skip_prefix(opt, "find-renames", &opt)) {
4199                        if (*opt == 0 || *opt++ == '=')
4200                                cmd = 'M';
4201                }
4202        }
4203        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4204                return -1; /* that is not a -M, -C, or -B option */
4205
4206        opt1 = parse_rename_score(&opt);
4207        if (cmd != 'B')
4208                opt2 = 0;
4209        else {
4210                if (*opt == 0)
4211                        opt2 = 0;
4212                else if (*opt != '/')
4213                        return -1; /* we expect -B80/99 or -B80 */
4214                else {
4215                        opt++;
4216                        opt2 = parse_rename_score(&opt);
4217                }
4218        }
4219        if (*opt != 0)
4220                return -1;
4221        return opt1 | (opt2 << 16);
4222}
4223
4224struct diff_queue_struct diff_queued_diff;
4225
4226void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4227{
4228        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4229        queue->queue[queue->nr++] = dp;
4230}
4231
4232struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4233                                 struct diff_filespec *one,
4234                                 struct diff_filespec *two)
4235{
4236        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4237        dp->one = one;
4238        dp->two = two;
4239        if (queue)
4240                diff_q(queue, dp);
4241        return dp;
4242}
4243
4244void diff_free_filepair(struct diff_filepair *p)
4245{
4246        free_filespec(p->one);
4247        free_filespec(p->two);
4248        free(p);
4249}
4250
4251const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4252{
4253        int abblen;
4254        const char *abbrev;
4255
4256        if (len == GIT_SHA1_HEXSZ)
4257                return oid_to_hex(oid);
4258
4259        abbrev = diff_abbrev_oid(oid, len);
4260        abblen = strlen(abbrev);
4261
4262        /*
4263         * In well-behaved cases, where the abbbreviated result is the
4264         * same as the requested length, append three dots after the
4265         * abbreviation (hence the whole logic is limited to the case
4266         * where abblen < 37); when the actual abbreviated result is a
4267         * bit longer than the requested length, we reduce the number
4268         * of dots so that they match the well-behaved ones.  However,
4269         * if the actual abbreviation is longer than the requested
4270         * length by more than three, we give up on aligning, and add
4271         * three dots anyway, to indicate that the output is not the
4272         * full object name.  Yes, this may be suboptimal, but this
4273         * appears only in "diff --raw --abbrev" output and it is not
4274         * worth the effort to change it now.  Note that this would
4275         * likely to work fine when the automatic sizing of default
4276         * abbreviation length is used--we would be fed -1 in "len" in
4277         * that case, and will end up always appending three-dots, but
4278         * the automatic sizing is supposed to give abblen that ensures
4279         * uniqueness across all objects (statistically speaking).
4280         */
4281        if (abblen < GIT_SHA1_HEXSZ - 3) {
4282                static char hex[GIT_MAX_HEXSZ + 1];
4283                if (len < abblen && abblen <= len + 2)
4284                        xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4285                else
4286                        xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4287                return hex;
4288        }
4289
4290        return oid_to_hex(oid);
4291}
4292
4293static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4294{
4295        int line_termination = opt->line_termination;
4296        int inter_name_termination = line_termination ? '\t' : '\0';
4297
4298        fprintf(opt->file, "%s", diff_line_prefix(opt));
4299        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4300                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4301                        diff_aligned_abbrev(&p->one->oid, opt->abbrev));
4302                fprintf(opt->file, "%s ",
4303                        diff_aligned_abbrev(&p->two->oid, opt->abbrev));
4304        }
4305        if (p->score) {
4306                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4307                        inter_name_termination);
4308        } else {
4309                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4310        }
4311
4312        if (p->status == DIFF_STATUS_COPIED ||
4313            p->status == DIFF_STATUS_RENAMED) {
4314                const char *name_a, *name_b;
4315                name_a = p->one->path;
4316                name_b = p->two->path;
4317                strip_prefix(opt->prefix_length, &name_a, &name_b);
4318                write_name_quoted(name_a, opt->file, inter_name_termination);
4319                write_name_quoted(name_b, opt->file, line_termination);
4320        } else {
4321                const char *name_a, *name_b;
4322                name_a = p->one->mode ? p->one->path : p->two->path;
4323                name_b = NULL;
4324                strip_prefix(opt->prefix_length, &name_a, &name_b);
4325                write_name_quoted(name_a, opt->file, line_termination);
4326        }
4327}
4328
4329int diff_unmodified_pair(struct diff_filepair *p)
4330{
4331        /* This function is written stricter than necessary to support
4332         * the currently implemented transformers, but the idea is to
4333         * let transformers to produce diff_filepairs any way they want,
4334         * and filter and clean them up here before producing the output.
4335         */
4336        struct diff_filespec *one = p->one, *two = p->two;
4337
4338        if (DIFF_PAIR_UNMERGED(p))
4339                return 0; /* unmerged is interesting */
4340
4341        /* deletion, addition, mode or type change
4342         * and rename are all interesting.
4343         */
4344        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4345            DIFF_PAIR_MODE_CHANGED(p) ||
4346            strcmp(one->path, two->path))
4347                return 0;
4348
4349        /* both are valid and point at the same path.  that is, we are
4350         * dealing with a change.
4351         */
4352        if (one->oid_valid && two->oid_valid &&
4353            !oidcmp(&one->oid, &two->oid) &&
4354            !one->dirty_submodule && !two->dirty_submodule)
4355                return 1; /* no change */
4356        if (!one->oid_valid && !two->oid_valid)
4357                return 1; /* both look at the same file on the filesystem. */
4358        return 0;
4359}
4360
4361static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4362{
4363        if (diff_unmodified_pair(p))
4364                return;
4365
4366        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4367            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4368                return; /* no tree diffs in patch format */
4369
4370        run_diff(p, o);
4371}
4372
4373static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4374                            struct diffstat_t *diffstat)
4375{
4376        if (diff_unmodified_pair(p))
4377                return;
4378
4379        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4380            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4381                return; /* no useful stat for tree diffs */
4382
4383        run_diffstat(p, o, diffstat);
4384}
4385
4386static void diff_flush_checkdiff(struct diff_filepair *p,
4387                struct diff_options *o)
4388{
4389        if (diff_unmodified_pair(p))
4390                return;
4391
4392        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4393            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4394                return; /* nothing to check in tree diffs */
4395
4396        run_checkdiff(p, o);
4397}
4398
4399int diff_queue_is_empty(void)
4400{
4401        struct diff_queue_struct *q = &diff_queued_diff;
4402        int i;
4403        for (i = 0; i < q->nr; i++)
4404                if (!diff_unmodified_pair(q->queue[i]))
4405                        return 0;
4406        return 1;
4407}
4408
4409#if DIFF_DEBUG
4410void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4411{
4412        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4413                x, one ? one : "",
4414                s->path,
4415                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4416                s->mode,
4417                s->oid_valid ? oid_to_hex(&s->oid) : "");
4418        fprintf(stderr, "queue[%d] %s size %lu\n",
4419                x, one ? one : "",
4420                s->size);
4421}
4422
4423void diff_debug_filepair(const struct diff_filepair *p, int i)
4424{
4425        diff_debug_filespec(p->one, i, "one");
4426        diff_debug_filespec(p->two, i, "two");
4427        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4428                p->score, p->status ? p->status : '?',
4429                p->one->rename_used, p->broken_pair);
4430}
4431
4432void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4433{
4434        int i;
4435        if (msg)
4436                fprintf(stderr, "%s\n", msg);
4437        fprintf(stderr, "q->nr = %d\n", q->nr);
4438        for (i = 0; i < q->nr; i++) {
4439                struct diff_filepair *p = q->queue[i];
4440                diff_debug_filepair(p, i);
4441        }
4442}
4443#endif
4444
4445static void diff_resolve_rename_copy(void)
4446{
4447        int i;
4448        struct diff_filepair *p;
4449        struct diff_queue_struct *q = &diff_queued_diff;
4450
4451        diff_debug_queue("resolve-rename-copy", q);
4452
4453        for (i = 0; i < q->nr; i++) {
4454                p = q->queue[i];
4455                p->status = 0; /* undecided */
4456                if (DIFF_PAIR_UNMERGED(p))
4457                        p->status = DIFF_STATUS_UNMERGED;
4458                else if (!DIFF_FILE_VALID(p->one))
4459                        p->status = DIFF_STATUS_ADDED;
4460                else if (!DIFF_FILE_VALID(p->two))
4461                        p->status = DIFF_STATUS_DELETED;
4462                else if (DIFF_PAIR_TYPE_CHANGED(p))
4463                        p->status = DIFF_STATUS_TYPE_CHANGED;
4464
4465                /* from this point on, we are dealing with a pair
4466                 * whose both sides are valid and of the same type, i.e.
4467                 * either in-place edit or rename/copy edit.
4468                 */
4469                else if (DIFF_PAIR_RENAME(p)) {
4470                        /*
4471                         * A rename might have re-connected a broken
4472                         * pair up, causing the pathnames to be the
4473                         * same again. If so, that's not a rename at
4474                         * all, just a modification..
4475                         *
4476                         * Otherwise, see if this source was used for
4477                         * multiple renames, in which case we decrement
4478                         * the count, and call it a copy.
4479                         */
4480                        if (!strcmp(p->one->path, p->two->path))
4481                                p->status = DIFF_STATUS_MODIFIED;
4482                        else if (--p->one->rename_used > 0)
4483                                p->status = DIFF_STATUS_COPIED;
4484                        else
4485                                p->status = DIFF_STATUS_RENAMED;
4486                }
4487                else if (oidcmp(&p->one->oid, &p->two->oid) ||
4488                         p->one->mode != p->two->mode ||
4489                         p->one->dirty_submodule ||
4490                         p->two->dirty_submodule ||
4491                         is_null_oid(&p->one->oid))
4492                        p->status = DIFF_STATUS_MODIFIED;
4493                else {
4494                        /* This is a "no-change" entry and should not
4495                         * happen anymore, but prepare for broken callers.
4496                         */
4497                        error("feeding unmodified %s to diffcore",
4498                              p->one->path);
4499                        p->status = DIFF_STATUS_UNKNOWN;
4500                }
4501        }
4502        diff_debug_queue("resolve-rename-copy done", q);
4503}
4504
4505static int check_pair_status(struct diff_filepair *p)
4506{
4507        switch (p->status) {
4508        case DIFF_STATUS_UNKNOWN:
4509                return 0;
4510        case 0:
4511                die("internal error in diff-resolve-rename-copy");
4512        default:
4513                return 1;
4514        }
4515}
4516
4517static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4518{
4519        int fmt = opt->output_format;
4520
4521        if (fmt & DIFF_FORMAT_CHECKDIFF)
4522                diff_flush_checkdiff(p, opt);
4523        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4524                diff_flush_raw(p, opt);
4525        else if (fmt & DIFF_FORMAT_NAME) {
4526                const char *name_a, *name_b;
4527                name_a = p->two->path;
4528                name_b = NULL;
4529                strip_prefix(opt->prefix_length, &name_a, &name_b);
4530                fprintf(opt->file, "%s", diff_line_prefix(opt));
4531                write_name_quoted(name_a, opt->file, opt->line_termination);
4532        }
4533}
4534
4535static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4536{
4537        if (fs->mode)
4538                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4539        else
4540                fprintf(file, " %s ", newdelete);
4541        write_name_quoted(fs->path, file, '\n');
4542}
4543
4544
4545static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4546                const char *line_prefix)
4547{
4548        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4549                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4550                        p->two->mode, show_name ? ' ' : '\n');
4551                if (show_name) {
4552                        write_name_quoted(p->two->path, file, '\n');
4553                }
4554        }
4555}
4556
4557static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4558                        const char *line_prefix)
4559{
4560        char *names = pprint_rename(p->one->path, p->two->path);
4561
4562        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4563        free(names);
4564        show_mode_change(file, p, 0, line_prefix);
4565}
4566
4567static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4568{
4569        FILE *file = opt->file;
4570        const char *line_prefix = diff_line_prefix(opt);
4571
4572        switch(p->status) {
4573        case DIFF_STATUS_DELETED:
4574                fputs(line_prefix, file);
4575                show_file_mode_name(file, "delete", p->one);
4576                break;
4577        case DIFF_STATUS_ADDED:
4578                fputs(line_prefix, file);
4579                show_file_mode_name(file, "create", p->two);
4580                break;
4581        case DIFF_STATUS_COPIED:
4582                fputs(line_prefix, file);
4583                show_rename_copy(file, "copy", p, line_prefix);
4584                break;
4585        case DIFF_STATUS_RENAMED:
4586                fputs(line_prefix, file);
4587                show_rename_copy(file, "rename", p, line_prefix);
4588                break;
4589        default:
4590                if (p->score) {
4591                        fprintf(file, "%s rewrite ", line_prefix);
4592                        write_name_quoted(p->two->path, file, ' ');
4593                        fprintf(file, "(%d%%)\n", similarity_index(p));
4594                }
4595                show_mode_change(file, p, !p->score, line_prefix);
4596                break;
4597        }
4598}
4599
4600struct patch_id_t {
4601        git_SHA_CTX *ctx;
4602        int patchlen;
4603};
4604
4605static int remove_space(char *line, int len)
4606{
4607        int i;
4608        char *dst = line;
4609        unsigned char c;
4610
4611        for (i = 0; i < len; i++)
4612                if (!isspace((c = line[i])))
4613                        *dst++ = c;
4614
4615        return dst - line;
4616}
4617
4618static void patch_id_consume(void *priv, char *line, unsigned long len)
4619{
4620        struct patch_id_t *data = priv;
4621        int new_len;
4622
4623        /* Ignore line numbers when computing the SHA1 of the patch */
4624        if (starts_with(line, "@@ -"))
4625                return;
4626
4627        new_len = remove_space(line, len);
4628
4629        git_SHA1_Update(data->ctx, line, new_len);
4630        data->patchlen += new_len;
4631}
4632
4633static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
4634{
4635        git_SHA1_Update(ctx, str, strlen(str));
4636}
4637
4638static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
4639{
4640        /* large enough for 2^32 in octal */
4641        char buf[12];
4642        int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
4643        git_SHA1_Update(ctx, buf, len);
4644}
4645
4646/* returns 0 upon success, and writes result into sha1 */
4647static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
4648{
4649        struct diff_queue_struct *q = &diff_queued_diff;
4650        int i;
4651        git_SHA_CTX ctx;
4652        struct patch_id_t data;
4653
4654        git_SHA1_Init(&ctx);
4655        memset(&data, 0, sizeof(struct patch_id_t));
4656        data.ctx = &ctx;
4657
4658        for (i = 0; i < q->nr; i++) {
4659                xpparam_t xpp;
4660                xdemitconf_t xecfg;
4661                mmfile_t mf1, mf2;
4662                struct diff_filepair *p = q->queue[i];
4663                int len1, len2;
4664
4665                memset(&xpp, 0, sizeof(xpp));
4666                memset(&xecfg, 0, sizeof(xecfg));
4667                if (p->status == 0)
4668                        return error("internal diff status error");
4669                if (p->status == DIFF_STATUS_UNKNOWN)
4670                        continue;
4671                if (diff_unmodified_pair(p))
4672                        continue;
4673                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4674                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4675                        continue;
4676                if (DIFF_PAIR_UNMERGED(p))
4677                        continue;
4678
4679                diff_fill_oid_info(p->one);
4680                diff_fill_oid_info(p->two);
4681
4682                len1 = remove_space(p->one->path, strlen(p->one->path));
4683                len2 = remove_space(p->two->path, strlen(p->two->path));
4684                patch_id_add_string(&ctx, "diff--git");
4685                patch_id_add_string(&ctx, "a/");
4686                git_SHA1_Update(&ctx, p->one->path, len1);
4687                patch_id_add_string(&ctx, "b/");
4688                git_SHA1_Update(&ctx, p->two->path, len2);
4689
4690                if (p->one->mode == 0) {
4691                        patch_id_add_string(&ctx, "newfilemode");
4692                        patch_id_add_mode(&ctx, p->two->mode);
4693                        patch_id_add_string(&ctx, "---/dev/null");
4694                        patch_id_add_string(&ctx, "+++b/");
4695                        git_SHA1_Update(&ctx, p->two->path, len2);
4696                } else if (p->two->mode == 0) {
4697                        patch_id_add_string(&ctx, "deletedfilemode");
4698                        patch_id_add_mode(&ctx, p->one->mode);
4699                        patch_id_add_string(&ctx, "---a/");
4700                        git_SHA1_Update(&ctx, p->one->path, len1);
4701                        patch_id_add_string(&ctx, "+++/dev/null");
4702                } else {
4703                        patch_id_add_string(&ctx, "---a/");
4704                        git_SHA1_Update(&ctx, p->one->path, len1);
4705                        patch_id_add_string(&ctx, "+++b/");
4706                        git_SHA1_Update(&ctx, p->two->path, len2);
4707                }
4708
4709                if (diff_header_only)
4710                        continue;
4711
4712                if (fill_mmfile(&mf1, p->one) < 0 ||
4713                    fill_mmfile(&mf2, p->two) < 0)
4714                        return error("unable to read files to diff");
4715
4716                if (diff_filespec_is_binary(p->one) ||
4717                    diff_filespec_is_binary(p->two)) {
4718                        git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
4719                                        GIT_SHA1_HEXSZ);
4720                        git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
4721                                        GIT_SHA1_HEXSZ);
4722                        continue;
4723                }
4724
4725                xpp.flags = 0;
4726                xecfg.ctxlen = 3;
4727                xecfg.flags = 0;
4728                if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4729                                  &xpp, &xecfg))
4730                        return error("unable to generate patch-id diff for %s",
4731                                     p->one->path);
4732        }
4733
4734        git_SHA1_Final(oid->hash, &ctx);
4735        return 0;
4736}
4737
4738int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
4739{
4740        struct diff_queue_struct *q = &diff_queued_diff;
4741        int i;
4742        int result = diff_get_patch_id(options, oid, diff_header_only);
4743
4744        for (i = 0; i < q->nr; i++)
4745                diff_free_filepair(q->queue[i]);
4746
4747        free(q->queue);
4748        DIFF_QUEUE_CLEAR(q);
4749
4750        return result;
4751}
4752
4753static int is_summary_empty(const struct diff_queue_struct *q)
4754{
4755        int i;
4756
4757        for (i = 0; i < q->nr; i++) {
4758                const struct diff_filepair *p = q->queue[i];
4759
4760                switch (p->status) {
4761                case DIFF_STATUS_DELETED:
4762                case DIFF_STATUS_ADDED:
4763                case DIFF_STATUS_COPIED:
4764                case DIFF_STATUS_RENAMED:
4765                        return 0;
4766                default:
4767                        if (p->score)
4768                                return 0;
4769                        if (p->one->mode && p->two->mode &&
4770                            p->one->mode != p->two->mode)
4771                                return 0;
4772                        break;
4773                }
4774        }
4775        return 1;
4776}
4777
4778static const char rename_limit_warning[] =
4779N_("inexact rename detection was skipped due to too many files.");
4780
4781static const char degrade_cc_to_c_warning[] =
4782N_("only found copies from modified paths due to too many files.");
4783
4784static const char rename_limit_advice[] =
4785N_("you may want to set your %s variable to at least "
4786   "%d and retry the command.");
4787
4788void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4789{
4790        if (degraded_cc)
4791                warning(_(degrade_cc_to_c_warning));
4792        else if (needed)
4793                warning(_(rename_limit_warning));
4794        else
4795                return;
4796        if (0 < needed && needed < 32767)
4797                warning(_(rename_limit_advice), varname, needed);
4798}
4799
4800static void diff_flush_patch_all_file_pairs(struct diff_options *o)
4801{
4802        int i;
4803        struct diff_queue_struct *q = &diff_queued_diff;
4804
4805        if (WSEH_NEW & WS_RULE_MASK)
4806                die("BUG: WS rules bit mask overlaps with diff symbol flags");
4807
4808        for (i = 0; i < q->nr; i++) {
4809                struct diff_filepair *p = q->queue[i];
4810                if (check_pair_status(p))
4811                        diff_flush_patch(p, o);
4812        }
4813}
4814
4815void diff_flush(struct diff_options *options)
4816{
4817        struct diff_queue_struct *q = &diff_queued_diff;
4818        int i, output_format = options->output_format;
4819        int separator = 0;
4820        int dirstat_by_line = 0;
4821
4822        /*
4823         * Order: raw, stat, summary, patch
4824         * or:    name/name-status/checkdiff (other bits clear)
4825         */
4826        if (!q->nr)
4827                goto free_queue;
4828
4829        if (output_format & (DIFF_FORMAT_RAW |
4830                             DIFF_FORMAT_NAME |
4831                             DIFF_FORMAT_NAME_STATUS |
4832                             DIFF_FORMAT_CHECKDIFF)) {
4833                for (i = 0; i < q->nr; i++) {
4834                        struct diff_filepair *p = q->queue[i];
4835                        if (check_pair_status(p))
4836                                flush_one_pair(p, options);
4837                }
4838                separator++;
4839        }
4840
4841        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4842                dirstat_by_line = 1;
4843
4844        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4845            dirstat_by_line) {
4846                struct diffstat_t diffstat;
4847
4848                memset(&diffstat, 0, sizeof(struct diffstat_t));
4849                for (i = 0; i < q->nr; i++) {
4850                        struct diff_filepair *p = q->queue[i];
4851                        if (check_pair_status(p))
4852                                diff_flush_stat(p, options, &diffstat);
4853                }
4854                if (output_format & DIFF_FORMAT_NUMSTAT)
4855                        show_numstat(&diffstat, options);
4856                if (output_format & DIFF_FORMAT_DIFFSTAT)
4857                        show_stats(&diffstat, options);
4858                if (output_format & DIFF_FORMAT_SHORTSTAT)
4859                        show_shortstats(&diffstat, options);
4860                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4861                        show_dirstat_by_line(&diffstat, options);
4862                free_diffstat_info(&diffstat);
4863                separator++;
4864        }
4865        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4866                show_dirstat(options);
4867
4868        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4869                for (i = 0; i < q->nr; i++) {
4870                        diff_summary(options, q->queue[i]);
4871                }
4872                separator++;
4873        }
4874
4875        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4876            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4877            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4878                /*
4879                 * run diff_flush_patch for the exit status. setting
4880                 * options->file to /dev/null should be safe, because we
4881                 * aren't supposed to produce any output anyway.
4882                 */
4883                if (options->close_file)
4884                        fclose(options->file);
4885                options->file = xfopen("/dev/null", "w");
4886                options->close_file = 1;
4887                for (i = 0; i < q->nr; i++) {
4888                        struct diff_filepair *p = q->queue[i];
4889                        if (check_pair_status(p))
4890                                diff_flush_patch(p, options);
4891                        if (options->found_changes)
4892                                break;
4893                }
4894        }
4895
4896        if (output_format & DIFF_FORMAT_PATCH) {
4897                if (separator) {
4898                        emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
4899                        if (options->stat_sep) {
4900                                /* attach patch instead of inline */
4901                                fputs(options->stat_sep, options->file);
4902                        }
4903                }
4904
4905                diff_flush_patch_all_file_pairs(options);
4906        }
4907
4908        if (output_format & DIFF_FORMAT_CALLBACK)
4909                options->format_callback(q, options, options->format_callback_data);
4910
4911        for (i = 0; i < q->nr; i++)
4912                diff_free_filepair(q->queue[i]);
4913free_queue:
4914        free(q->queue);
4915        DIFF_QUEUE_CLEAR(q);
4916        if (options->close_file)
4917                fclose(options->file);
4918
4919        /*
4920         * Report the content-level differences with HAS_CHANGES;
4921         * diff_addremove/diff_change does not set the bit when
4922         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4923         */
4924        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4925                if (options->found_changes)
4926                        DIFF_OPT_SET(options, HAS_CHANGES);
4927                else
4928                        DIFF_OPT_CLR(options, HAS_CHANGES);
4929        }
4930}
4931
4932static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4933{
4934        return (((p->status == DIFF_STATUS_MODIFIED) &&
4935                 ((p->score &&
4936                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4937                  (!p->score &&
4938                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4939                ((p->status != DIFF_STATUS_MODIFIED) &&
4940                 filter_bit_tst(p->status, options)));
4941}
4942
4943static void diffcore_apply_filter(struct diff_options *options)
4944{
4945        int i;
4946        struct diff_queue_struct *q = &diff_queued_diff;
4947        struct diff_queue_struct outq;
4948
4949        DIFF_QUEUE_CLEAR(&outq);
4950
4951        if (!options->filter)
4952                return;
4953
4954        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4955                int found;
4956                for (i = found = 0; !found && i < q->nr; i++) {
4957                        if (match_filter(options, q->queue[i]))
4958                                found++;
4959                }
4960                if (found)
4961                        return;
4962
4963                /* otherwise we will clear the whole queue
4964                 * by copying the empty outq at the end of this
4965                 * function, but first clear the current entries
4966                 * in the queue.
4967                 */
4968                for (i = 0; i < q->nr; i++)
4969                        diff_free_filepair(q->queue[i]);
4970        }
4971        else {
4972                /* Only the matching ones */
4973                for (i = 0; i < q->nr; i++) {
4974                        struct diff_filepair *p = q->queue[i];
4975                        if (match_filter(options, p))
4976                                diff_q(&outq, p);
4977                        else
4978                                diff_free_filepair(p);
4979                }
4980        }
4981        free(q->queue);
4982        *q = outq;
4983}
4984
4985/* Check whether two filespecs with the same mode and size are identical */
4986static int diff_filespec_is_identical(struct diff_filespec *one,
4987                                      struct diff_filespec *two)
4988{
4989        if (S_ISGITLINK(one->mode))
4990                return 0;
4991        if (diff_populate_filespec(one, 0))
4992                return 0;
4993        if (diff_populate_filespec(two, 0))
4994                return 0;
4995        return !memcmp(one->data, two->data, one->size);
4996}
4997
4998static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4999{
5000        if (p->done_skip_stat_unmatch)
5001                return p->skip_stat_unmatch_result;
5002
5003        p->done_skip_stat_unmatch = 1;
5004        p->skip_stat_unmatch_result = 0;
5005        /*
5006         * 1. Entries that come from stat info dirtiness
5007         *    always have both sides (iow, not create/delete),
5008         *    one side of the object name is unknown, with
5009         *    the same mode and size.  Keep the ones that
5010         *    do not match these criteria.  They have real
5011         *    differences.
5012         *
5013         * 2. At this point, the file is known to be modified,
5014         *    with the same mode and size, and the object
5015         *    name of one side is unknown.  Need to inspect
5016         *    the identical contents.
5017         */
5018        if (!DIFF_FILE_VALID(p->one) || /* (1) */
5019            !DIFF_FILE_VALID(p->two) ||
5020            (p->one->oid_valid && p->two->oid_valid) ||
5021            (p->one->mode != p->two->mode) ||
5022            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
5023            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
5024            (p->one->size != p->two->size) ||
5025            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
5026                p->skip_stat_unmatch_result = 1;
5027        return p->skip_stat_unmatch_result;
5028}
5029
5030static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
5031{
5032        int i;
5033        struct diff_queue_struct *q = &diff_queued_diff;
5034        struct diff_queue_struct outq;
5035        DIFF_QUEUE_CLEAR(&outq);
5036
5037        for (i = 0; i < q->nr; i++) {
5038                struct diff_filepair *p = q->queue[i];
5039
5040                if (diff_filespec_check_stat_unmatch(p))
5041                        diff_q(&outq, p);
5042                else {
5043                        /*
5044                         * The caller can subtract 1 from skip_stat_unmatch
5045                         * to determine how many paths were dirty only
5046                         * due to stat info mismatch.
5047                         */
5048                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
5049                                diffopt->skip_stat_unmatch++;
5050                        diff_free_filepair(p);
5051                }
5052        }
5053        free(q->queue);
5054        *q = outq;
5055}
5056
5057static int diffnamecmp(const void *a_, const void *b_)
5058{
5059        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
5060        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
5061        const char *name_a, *name_b;
5062
5063        name_a = a->one ? a->one->path : a->two->path;
5064        name_b = b->one ? b->one->path : b->two->path;
5065        return strcmp(name_a, name_b);
5066}
5067
5068void diffcore_fix_diff_index(struct diff_options *options)
5069{
5070        struct diff_queue_struct *q = &diff_queued_diff;
5071        QSORT(q->queue, q->nr, diffnamecmp);
5072}
5073
5074void diffcore_std(struct diff_options *options)
5075{
5076        /* NOTE please keep the following in sync with diff_tree_combined() */
5077        if (options->skip_stat_unmatch)
5078                diffcore_skip_stat_unmatch(options);
5079        if (!options->found_follow) {
5080                /* See try_to_follow_renames() in tree-diff.c */
5081                if (options->break_opt != -1)
5082                        diffcore_break(options->break_opt);
5083                if (options->detect_rename)
5084                        diffcore_rename(options);
5085                if (options->break_opt != -1)
5086                        diffcore_merge_broken();
5087        }
5088        if (options->pickaxe)
5089                diffcore_pickaxe(options);
5090        if (options->orderfile)
5091                diffcore_order(options->orderfile);
5092        if (!options->found_follow)
5093                /* See try_to_follow_renames() in tree-diff.c */
5094                diff_resolve_rename_copy();
5095        diffcore_apply_filter(options);
5096
5097        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5098                DIFF_OPT_SET(options, HAS_CHANGES);
5099        else
5100                DIFF_OPT_CLR(options, HAS_CHANGES);
5101
5102        options->found_follow = 0;
5103}
5104
5105int diff_result_code(struct diff_options *opt, int status)
5106{
5107        int result = 0;
5108
5109        diff_warn_rename_limit("diff.renameLimit",
5110                               opt->needed_rename_limit,
5111                               opt->degraded_cc_to_c);
5112        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5113            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5114                return status;
5115        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5116            DIFF_OPT_TST(opt, HAS_CHANGES))
5117                result |= 01;
5118        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5119            DIFF_OPT_TST(opt, CHECK_FAILED))
5120                result |= 02;
5121        return result;
5122}
5123
5124int diff_can_quit_early(struct diff_options *opt)
5125{
5126        return (DIFF_OPT_TST(opt, QUICK) &&
5127                !opt->filter &&
5128                DIFF_OPT_TST(opt, HAS_CHANGES));
5129}
5130
5131/*
5132 * Shall changes to this submodule be ignored?
5133 *
5134 * Submodule changes can be configured to be ignored separately for each path,
5135 * but that configuration can be overridden from the command line.
5136 */
5137static int is_submodule_ignored(const char *path, struct diff_options *options)
5138{
5139        int ignored = 0;
5140        unsigned orig_flags = options->flags;
5141        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
5142                set_diffopt_flags_from_submodule_config(options, path);
5143        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
5144                ignored = 1;
5145        options->flags = orig_flags;
5146        return ignored;
5147}
5148
5149void diff_addremove(struct diff_options *options,
5150                    int addremove, unsigned mode,
5151                    const struct object_id *oid,
5152                    int oid_valid,
5153                    const char *concatpath, unsigned dirty_submodule)
5154{
5155        struct diff_filespec *one, *two;
5156
5157        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5158                return;
5159
5160        /* This may look odd, but it is a preparation for
5161         * feeding "there are unchanged files which should
5162         * not produce diffs, but when you are doing copy
5163         * detection you would need them, so here they are"
5164         * entries to the diff-core.  They will be prefixed
5165         * with something like '=' or '*' (I haven't decided
5166         * which but should not make any difference).
5167         * Feeding the same new and old to diff_change()
5168         * also has the same effect.
5169         * Before the final output happens, they are pruned after
5170         * merged into rename/copy pairs as appropriate.
5171         */
5172        if (DIFF_OPT_TST(options, REVERSE_DIFF))
5173                addremove = (addremove == '+' ? '-' :
5174                             addremove == '-' ? '+' : addremove);
5175
5176        if (options->prefix &&
5177            strncmp(concatpath, options->prefix, options->prefix_length))
5178                return;
5179
5180        one = alloc_filespec(concatpath);
5181        two = alloc_filespec(concatpath);
5182
5183        if (addremove != '+')
5184                fill_filespec(one, oid, oid_valid, mode);
5185        if (addremove != '-') {
5186                fill_filespec(two, oid, oid_valid, mode);
5187                two->dirty_submodule = dirty_submodule;
5188        }
5189
5190        diff_queue(&diff_queued_diff, one, two);
5191        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5192                DIFF_OPT_SET(options, HAS_CHANGES);
5193}
5194
5195void diff_change(struct diff_options *options,
5196                 unsigned old_mode, unsigned new_mode,
5197                 const struct object_id *old_oid,
5198                 const struct object_id *new_oid,
5199                 int old_oid_valid, int new_oid_valid,
5200                 const char *concatpath,
5201                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5202{
5203        struct diff_filespec *one, *two;
5204        struct diff_filepair *p;
5205
5206        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5207            is_submodule_ignored(concatpath, options))
5208                return;
5209
5210        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5211                SWAP(old_mode, new_mode);
5212                SWAP(old_oid, new_oid);
5213                SWAP(old_oid_valid, new_oid_valid);
5214                SWAP(old_dirty_submodule, new_dirty_submodule);
5215        }
5216
5217        if (options->prefix &&
5218            strncmp(concatpath, options->prefix, options->prefix_length))
5219                return;
5220
5221        one = alloc_filespec(concatpath);
5222        two = alloc_filespec(concatpath);
5223        fill_filespec(one, old_oid, old_oid_valid, old_mode);
5224        fill_filespec(two, new_oid, new_oid_valid, new_mode);
5225        one->dirty_submodule = old_dirty_submodule;
5226        two->dirty_submodule = new_dirty_submodule;
5227        p = diff_queue(&diff_queued_diff, one, two);
5228
5229        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5230                return;
5231
5232        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5233            !diff_filespec_check_stat_unmatch(p))
5234                return;
5235
5236        DIFF_OPT_SET(options, HAS_CHANGES);
5237}
5238
5239struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5240{
5241        struct diff_filepair *pair;
5242        struct diff_filespec *one, *two;
5243
5244        if (options->prefix &&
5245            strncmp(path, options->prefix, options->prefix_length))
5246                return NULL;
5247
5248        one = alloc_filespec(path);
5249        two = alloc_filespec(path);
5250        pair = diff_queue(&diff_queued_diff, one, two);
5251        pair->is_unmerged = 1;
5252        return pair;
5253}
5254
5255static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5256                size_t *outsize)
5257{
5258        struct diff_tempfile *temp;
5259        const char *argv[3];
5260        const char **arg = argv;
5261        struct child_process child = CHILD_PROCESS_INIT;
5262        struct strbuf buf = STRBUF_INIT;
5263        int err = 0;
5264
5265        temp = prepare_temp_file(spec->path, spec);
5266        *arg++ = pgm;
5267        *arg++ = temp->name;
5268        *arg = NULL;
5269
5270        child.use_shell = 1;
5271        child.argv = argv;
5272        child.out = -1;
5273        if (start_command(&child)) {
5274                remove_tempfile();
5275                return NULL;
5276        }
5277
5278        if (strbuf_read(&buf, child.out, 0) < 0)
5279                err = error("error reading from textconv command '%s'", pgm);
5280        close(child.out);
5281
5282        if (finish_command(&child) || err) {
5283                strbuf_release(&buf);
5284                remove_tempfile();
5285                return NULL;
5286        }
5287        remove_tempfile();
5288
5289        return strbuf_detach(&buf, outsize);
5290}
5291
5292size_t fill_textconv(struct userdiff_driver *driver,
5293                     struct diff_filespec *df,
5294                     char **outbuf)
5295{
5296        size_t size;
5297
5298        if (!driver) {
5299                if (!DIFF_FILE_VALID(df)) {
5300                        *outbuf = "";
5301                        return 0;
5302                }
5303                if (diff_populate_filespec(df, 0))
5304                        die("unable to read files to diff");
5305                *outbuf = df->data;
5306                return df->size;
5307        }
5308
5309        if (!driver->textconv)
5310                die("BUG: fill_textconv called with non-textconv driver");
5311
5312        if (driver->textconv_cache && df->oid_valid) {
5313                *outbuf = notes_cache_get(driver->textconv_cache,
5314                                          &df->oid,
5315                                          &size);
5316                if (*outbuf)
5317                        return size;
5318        }
5319
5320        *outbuf = run_textconv(driver->textconv, df, &size);
5321        if (!*outbuf)
5322                die("unable to read files to diff");
5323
5324        if (driver->textconv_cache && df->oid_valid) {
5325                /* ignore errors, as we might be in a readonly repository */
5326                notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
5327                                size);
5328                /*
5329                 * we could save up changes and flush them all at the end,
5330                 * but we would need an extra call after all diffing is done.
5331                 * Since generating a cache entry is the slow path anyway,
5332                 * this extra overhead probably isn't a big deal.
5333                 */
5334                notes_cache_write(driver->textconv_cache);
5335        }
5336
5337        return size;
5338}
5339
5340int textconv_object(const char *path,
5341                    unsigned mode,
5342                    const struct object_id *oid,
5343                    int oid_valid,
5344                    char **buf,
5345                    unsigned long *buf_size)
5346{
5347        struct diff_filespec *df;
5348        struct userdiff_driver *textconv;
5349
5350        df = alloc_filespec(path);
5351        fill_filespec(df, oid, oid_valid, mode);
5352        textconv = get_textconv(df);
5353        if (!textconv) {
5354                free_filespec(df);
5355                return 0;
5356        }
5357
5358        *buf_size = fill_textconv(textconv, df, buf);
5359        free_filespec(df);
5360        return 1;
5361}
5362
5363void setup_diff_pager(struct diff_options *opt)
5364{
5365        /*
5366         * If the user asked for our exit code, then either they want --quiet
5367         * or --exit-code. We should definitely not bother with a pager in the
5368         * former case, as we will generate no output. Since we still properly
5369         * report our exit code even when a pager is run, we _could_ run a
5370         * pager with --exit-code. But since we have not done so historically,
5371         * and because it is easy to find people oneline advising "git diff
5372         * --exit-code" in hooks and other scripts, we do not do so.
5373         */
5374        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5375            check_pager_config("diff") != 0)
5376                setup_pager();
5377}