diff.con commit Merge branch 'ks/doc-fixes' into maint (0baf0b8)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "tempfile.h"
   6#include "quote.h"
   7#include "diff.h"
   8#include "diffcore.h"
   9#include "delta.h"
  10#include "xdiff-interface.h"
  11#include "color.h"
  12#include "attr.h"
  13#include "run-command.h"
  14#include "utf8.h"
  15#include "userdiff.h"
  16#include "submodule-config.h"
  17#include "submodule.h"
  18#include "ll-merge.h"
  19#include "string-list.h"
  20#include "argv-array.h"
  21#include "graph.h"
  22
  23#ifdef NO_FAST_WORKING_DIRECTORY
  24#define FAST_WORKING_DIRECTORY 0
  25#else
  26#define FAST_WORKING_DIRECTORY 1
  27#endif
  28
  29static int diff_detect_rename_default;
  30static int diff_indent_heuristic; /* experimental */
  31static int diff_rename_limit_default = 400;
  32static int diff_suppress_blank_empty;
  33static int diff_use_color_default = -1;
  34static int diff_context_default = 3;
  35static int diff_interhunk_context_default;
  36static const char *diff_word_regex_cfg;
  37static const char *external_diff_cmd_cfg;
  38static const char *diff_order_file_cfg;
  39int diff_auto_refresh_index = 1;
  40static int diff_mnemonic_prefix;
  41static int diff_no_prefix;
  42static int diff_stat_graph_width;
  43static int diff_dirstat_permille_default = 30;
  44static struct diff_options default_diff_options;
  45static long diff_algorithm;
  46static unsigned ws_error_highlight_default = WSEH_NEW;
  47
  48static char diff_colors[][COLOR_MAXLEN] = {
  49        GIT_COLOR_RESET,
  50        GIT_COLOR_NORMAL,       /* CONTEXT */
  51        GIT_COLOR_BOLD,         /* METAINFO */
  52        GIT_COLOR_CYAN,         /* FRAGINFO */
  53        GIT_COLOR_RED,          /* OLD */
  54        GIT_COLOR_GREEN,        /* NEW */
  55        GIT_COLOR_YELLOW,       /* COMMIT */
  56        GIT_COLOR_BG_RED,       /* WHITESPACE */
  57        GIT_COLOR_NORMAL,       /* FUNCINFO */
  58};
  59
  60static NORETURN void die_want_option(const char *option_name)
  61{
  62        die(_("option '%s' requires a value"), option_name);
  63}
  64
  65static int parse_diff_color_slot(const char *var)
  66{
  67        if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  68                return DIFF_CONTEXT;
  69        if (!strcasecmp(var, "meta"))
  70                return DIFF_METAINFO;
  71        if (!strcasecmp(var, "frag"))
  72                return DIFF_FRAGINFO;
  73        if (!strcasecmp(var, "old"))
  74                return DIFF_FILE_OLD;
  75        if (!strcasecmp(var, "new"))
  76                return DIFF_FILE_NEW;
  77        if (!strcasecmp(var, "commit"))
  78                return DIFF_COMMIT;
  79        if (!strcasecmp(var, "whitespace"))
  80                return DIFF_WHITESPACE;
  81        if (!strcasecmp(var, "func"))
  82                return DIFF_FUNCINFO;
  83        return -1;
  84}
  85
  86static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  87                                struct strbuf *errmsg)
  88{
  89        char *params_copy = xstrdup(params_string);
  90        struct string_list params = STRING_LIST_INIT_NODUP;
  91        int ret = 0;
  92        int i;
  93
  94        if (*params_copy)
  95                string_list_split_in_place(&params, params_copy, ',', -1);
  96        for (i = 0; i < params.nr; i++) {
  97                const char *p = params.items[i].string;
  98                if (!strcmp(p, "changes")) {
  99                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 100                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 101                } else if (!strcmp(p, "lines")) {
 102                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
 103                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 104                } else if (!strcmp(p, "files")) {
 105                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 106                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
 107                } else if (!strcmp(p, "noncumulative")) {
 108                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 109                } else if (!strcmp(p, "cumulative")) {
 110                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 111                } else if (isdigit(*p)) {
 112                        char *end;
 113                        int permille = strtoul(p, &end, 10) * 10;
 114                        if (*end == '.' && isdigit(*++end)) {
 115                                /* only use first digit */
 116                                permille += *end - '0';
 117                                /* .. and ignore any further digits */
 118                                while (isdigit(*++end))
 119                                        ; /* nothing */
 120                        }
 121                        if (!*end)
 122                                options->dirstat_permille = permille;
 123                        else {
 124                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 125                                            p);
 126                                ret++;
 127                        }
 128                } else {
 129                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 130                        ret++;
 131                }
 132
 133        }
 134        string_list_clear(&params, 0);
 135        free(params_copy);
 136        return ret;
 137}
 138
 139static int parse_submodule_params(struct diff_options *options, const char *value)
 140{
 141        if (!strcmp(value, "log"))
 142                options->submodule_format = DIFF_SUBMODULE_LOG;
 143        else if (!strcmp(value, "short"))
 144                options->submodule_format = DIFF_SUBMODULE_SHORT;
 145        else if (!strcmp(value, "diff"))
 146                options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 147        else
 148                return -1;
 149        return 0;
 150}
 151
 152static int git_config_rename(const char *var, const char *value)
 153{
 154        if (!value)
 155                return DIFF_DETECT_RENAME;
 156        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 157                return  DIFF_DETECT_COPY;
 158        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 159}
 160
 161long parse_algorithm_value(const char *value)
 162{
 163        if (!value)
 164                return -1;
 165        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 166                return 0;
 167        else if (!strcasecmp(value, "minimal"))
 168                return XDF_NEED_MINIMAL;
 169        else if (!strcasecmp(value, "patience"))
 170                return XDF_PATIENCE_DIFF;
 171        else if (!strcasecmp(value, "histogram"))
 172                return XDF_HISTOGRAM_DIFF;
 173        return -1;
 174}
 175
 176static int parse_one_token(const char **arg, const char *token)
 177{
 178        const char *rest;
 179        if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 180                *arg = rest;
 181                return 1;
 182        }
 183        return 0;
 184}
 185
 186static int parse_ws_error_highlight(const char *arg)
 187{
 188        const char *orig_arg = arg;
 189        unsigned val = 0;
 190
 191        while (*arg) {
 192                if (parse_one_token(&arg, "none"))
 193                        val = 0;
 194                else if (parse_one_token(&arg, "default"))
 195                        val = WSEH_NEW;
 196                else if (parse_one_token(&arg, "all"))
 197                        val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 198                else if (parse_one_token(&arg, "new"))
 199                        val |= WSEH_NEW;
 200                else if (parse_one_token(&arg, "old"))
 201                        val |= WSEH_OLD;
 202                else if (parse_one_token(&arg, "context"))
 203                        val |= WSEH_CONTEXT;
 204                else {
 205                        return -1 - (int)(arg - orig_arg);
 206                }
 207                if (*arg)
 208                        arg++;
 209        }
 210        return val;
 211}
 212
 213/*
 214 * These are to give UI layer defaults.
 215 * The core-level commands such as git-diff-files should
 216 * never be affected by the setting of diff.renames
 217 * the user happens to have in the configuration file.
 218 */
 219void init_diff_ui_defaults(void)
 220{
 221        diff_detect_rename_default = 1;
 222}
 223
 224int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 225{
 226        if (!strcmp(var, "diff.indentheuristic"))
 227                diff_indent_heuristic = git_config_bool(var, value);
 228        return 0;
 229}
 230
 231int git_diff_ui_config(const char *var, const char *value, void *cb)
 232{
 233        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 234                diff_use_color_default = git_config_colorbool(var, value);
 235                return 0;
 236        }
 237        if (!strcmp(var, "diff.context")) {
 238                diff_context_default = git_config_int(var, value);
 239                if (diff_context_default < 0)
 240                        return -1;
 241                return 0;
 242        }
 243        if (!strcmp(var, "diff.interhunkcontext")) {
 244                diff_interhunk_context_default = git_config_int(var, value);
 245                if (diff_interhunk_context_default < 0)
 246                        return -1;
 247                return 0;
 248        }
 249        if (!strcmp(var, "diff.renames")) {
 250                diff_detect_rename_default = git_config_rename(var, value);
 251                return 0;
 252        }
 253        if (!strcmp(var, "diff.autorefreshindex")) {
 254                diff_auto_refresh_index = git_config_bool(var, value);
 255                return 0;
 256        }
 257        if (!strcmp(var, "diff.mnemonicprefix")) {
 258                diff_mnemonic_prefix = git_config_bool(var, value);
 259                return 0;
 260        }
 261        if (!strcmp(var, "diff.noprefix")) {
 262                diff_no_prefix = git_config_bool(var, value);
 263                return 0;
 264        }
 265        if (!strcmp(var, "diff.statgraphwidth")) {
 266                diff_stat_graph_width = git_config_int(var, value);
 267                return 0;
 268        }
 269        if (!strcmp(var, "diff.external"))
 270                return git_config_string(&external_diff_cmd_cfg, var, value);
 271        if (!strcmp(var, "diff.wordregex"))
 272                return git_config_string(&diff_word_regex_cfg, var, value);
 273        if (!strcmp(var, "diff.orderfile"))
 274                return git_config_pathname(&diff_order_file_cfg, var, value);
 275
 276        if (!strcmp(var, "diff.ignoresubmodules"))
 277                handle_ignore_submodules_arg(&default_diff_options, value);
 278
 279        if (!strcmp(var, "diff.submodule")) {
 280                if (parse_submodule_params(&default_diff_options, value))
 281                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 282                                value);
 283                return 0;
 284        }
 285
 286        if (!strcmp(var, "diff.algorithm")) {
 287                diff_algorithm = parse_algorithm_value(value);
 288                if (diff_algorithm < 0)
 289                        return -1;
 290                return 0;
 291        }
 292
 293        if (git_diff_heuristic_config(var, value, cb) < 0)
 294                return -1;
 295
 296        if (!strcmp(var, "diff.wserrorhighlight")) {
 297                int val = parse_ws_error_highlight(value);
 298                if (val < 0)
 299                        return -1;
 300                ws_error_highlight_default = val;
 301                return 0;
 302        }
 303
 304        if (git_color_config(var, value, cb) < 0)
 305                return -1;
 306
 307        return git_diff_basic_config(var, value, cb);
 308}
 309
 310int git_diff_basic_config(const char *var, const char *value, void *cb)
 311{
 312        const char *name;
 313
 314        if (!strcmp(var, "diff.renamelimit")) {
 315                diff_rename_limit_default = git_config_int(var, value);
 316                return 0;
 317        }
 318
 319        if (userdiff_config(var, value) < 0)
 320                return -1;
 321
 322        if (skip_prefix(var, "diff.color.", &name) ||
 323            skip_prefix(var, "color.diff.", &name)) {
 324                int slot = parse_diff_color_slot(name);
 325                if (slot < 0)
 326                        return 0;
 327                if (!value)
 328                        return config_error_nonbool(var);
 329                return color_parse(value, diff_colors[slot]);
 330        }
 331
 332        /* like GNU diff's --suppress-blank-empty option  */
 333        if (!strcmp(var, "diff.suppressblankempty") ||
 334                        /* for backwards compatibility */
 335                        !strcmp(var, "diff.suppress-blank-empty")) {
 336                diff_suppress_blank_empty = git_config_bool(var, value);
 337                return 0;
 338        }
 339
 340        if (!strcmp(var, "diff.dirstat")) {
 341                struct strbuf errmsg = STRBUF_INIT;
 342                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 343                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 344                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 345                                errmsg.buf);
 346                strbuf_release(&errmsg);
 347                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 348                return 0;
 349        }
 350
 351        if (starts_with(var, "submodule."))
 352                return parse_submodule_config_option(var, value);
 353
 354        return git_default_config(var, value, cb);
 355}
 356
 357static char *quote_two(const char *one, const char *two)
 358{
 359        int need_one = quote_c_style(one, NULL, NULL, 1);
 360        int need_two = quote_c_style(two, NULL, NULL, 1);
 361        struct strbuf res = STRBUF_INIT;
 362
 363        if (need_one + need_two) {
 364                strbuf_addch(&res, '"');
 365                quote_c_style(one, &res, NULL, 1);
 366                quote_c_style(two, &res, NULL, 1);
 367                strbuf_addch(&res, '"');
 368        } else {
 369                strbuf_addstr(&res, one);
 370                strbuf_addstr(&res, two);
 371        }
 372        return strbuf_detach(&res, NULL);
 373}
 374
 375static const char *external_diff(void)
 376{
 377        static const char *external_diff_cmd = NULL;
 378        static int done_preparing = 0;
 379
 380        if (done_preparing)
 381                return external_diff_cmd;
 382        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 383        if (!external_diff_cmd)
 384                external_diff_cmd = external_diff_cmd_cfg;
 385        done_preparing = 1;
 386        return external_diff_cmd;
 387}
 388
 389/*
 390 * Keep track of files used for diffing. Sometimes such an entry
 391 * refers to a temporary file, sometimes to an existing file, and
 392 * sometimes to "/dev/null".
 393 */
 394static struct diff_tempfile {
 395        /*
 396         * filename external diff should read from, or NULL if this
 397         * entry is currently not in use:
 398         */
 399        const char *name;
 400
 401        char hex[GIT_MAX_HEXSZ + 1];
 402        char mode[10];
 403
 404        /*
 405         * If this diff_tempfile instance refers to a temporary file,
 406         * this tempfile object is used to manage its lifetime.
 407         */
 408        struct tempfile tempfile;
 409} diff_temp[2];
 410
 411typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 412
 413struct emit_callback {
 414        int color_diff;
 415        unsigned ws_rule;
 416        int blank_at_eof_in_preimage;
 417        int blank_at_eof_in_postimage;
 418        int lno_in_preimage;
 419        int lno_in_postimage;
 420        sane_truncate_fn truncate;
 421        const char **label_path;
 422        struct diff_words_data *diff_words;
 423        struct diff_options *opt;
 424        struct strbuf *header;
 425};
 426
 427static int count_lines(const char *data, int size)
 428{
 429        int count, ch, completely_empty = 1, nl_just_seen = 0;
 430        count = 0;
 431        while (0 < size--) {
 432                ch = *data++;
 433                if (ch == '\n') {
 434                        count++;
 435                        nl_just_seen = 1;
 436                        completely_empty = 0;
 437                }
 438                else {
 439                        nl_just_seen = 0;
 440                        completely_empty = 0;
 441                }
 442        }
 443        if (completely_empty)
 444                return 0;
 445        if (!nl_just_seen)
 446                count++; /* no trailing newline */
 447        return count;
 448}
 449
 450static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 451{
 452        if (!DIFF_FILE_VALID(one)) {
 453                mf->ptr = (char *)""; /* does not matter */
 454                mf->size = 0;
 455                return 0;
 456        }
 457        else if (diff_populate_filespec(one, 0))
 458                return -1;
 459
 460        mf->ptr = one->data;
 461        mf->size = one->size;
 462        return 0;
 463}
 464
 465/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 466static unsigned long diff_filespec_size(struct diff_filespec *one)
 467{
 468        if (!DIFF_FILE_VALID(one))
 469                return 0;
 470        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 471        return one->size;
 472}
 473
 474static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 475{
 476        char *ptr = mf->ptr;
 477        long size = mf->size;
 478        int cnt = 0;
 479
 480        if (!size)
 481                return cnt;
 482        ptr += size - 1; /* pointing at the very end */
 483        if (*ptr != '\n')
 484                ; /* incomplete line */
 485        else
 486                ptr--; /* skip the last LF */
 487        while (mf->ptr < ptr) {
 488                char *prev_eol;
 489                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 490                        if (*prev_eol == '\n')
 491                                break;
 492                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 493                        break;
 494                cnt++;
 495                ptr = prev_eol - 1;
 496        }
 497        return cnt;
 498}
 499
 500static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 501                               struct emit_callback *ecbdata)
 502{
 503        int l1, l2, at;
 504        unsigned ws_rule = ecbdata->ws_rule;
 505        l1 = count_trailing_blank(mf1, ws_rule);
 506        l2 = count_trailing_blank(mf2, ws_rule);
 507        if (l2 <= l1) {
 508                ecbdata->blank_at_eof_in_preimage = 0;
 509                ecbdata->blank_at_eof_in_postimage = 0;
 510                return;
 511        }
 512        at = count_lines(mf1->ptr, mf1->size);
 513        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 514
 515        at = count_lines(mf2->ptr, mf2->size);
 516        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 517}
 518
 519static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 520                        int first, const char *line, int len)
 521{
 522        int has_trailing_newline, has_trailing_carriage_return;
 523        int nofirst;
 524        FILE *file = o->file;
 525
 526        fputs(diff_line_prefix(o), file);
 527
 528        if (len == 0) {
 529                has_trailing_newline = (first == '\n');
 530                has_trailing_carriage_return = (!has_trailing_newline &&
 531                                                (first == '\r'));
 532                nofirst = has_trailing_newline || has_trailing_carriage_return;
 533        } else {
 534                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 535                if (has_trailing_newline)
 536                        len--;
 537                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 538                if (has_trailing_carriage_return)
 539                        len--;
 540                nofirst = 0;
 541        }
 542
 543        if (len || !nofirst) {
 544                fputs(set, file);
 545                if (!nofirst)
 546                        fputc(first, file);
 547                fwrite(line, len, 1, file);
 548                fputs(reset, file);
 549        }
 550        if (has_trailing_carriage_return)
 551                fputc('\r', file);
 552        if (has_trailing_newline)
 553                fputc('\n', file);
 554}
 555
 556static void emit_line(struct diff_options *o, const char *set, const char *reset,
 557                      const char *line, int len)
 558{
 559        emit_line_0(o, set, reset, line[0], line+1, len-1);
 560}
 561
 562static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 563{
 564        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 565              ecbdata->blank_at_eof_in_preimage &&
 566              ecbdata->blank_at_eof_in_postimage &&
 567              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 568              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 569                return 0;
 570        return ws_blank_line(line, len, ecbdata->ws_rule);
 571}
 572
 573static void emit_line_checked(const char *reset,
 574                              struct emit_callback *ecbdata,
 575                              const char *line, int len,
 576                              enum color_diff color,
 577                              unsigned ws_error_highlight,
 578                              char sign)
 579{
 580        const char *set = diff_get_color(ecbdata->color_diff, color);
 581        const char *ws = NULL;
 582
 583        if (ecbdata->opt->ws_error_highlight & ws_error_highlight) {
 584                ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 585                if (!*ws)
 586                        ws = NULL;
 587        }
 588
 589        if (!ws)
 590                emit_line_0(ecbdata->opt, set, reset, sign, line, len);
 591        else if (sign == '+' && new_blank_line_at_eof(ecbdata, line, len))
 592                /* Blank line at EOF - paint '+' as well */
 593                emit_line_0(ecbdata->opt, ws, reset, sign, line, len);
 594        else {
 595                /* Emit just the prefix, then the rest. */
 596                emit_line_0(ecbdata->opt, set, reset, sign, "", 0);
 597                ws_check_emit(line, len, ecbdata->ws_rule,
 598                              ecbdata->opt->file, set, reset, ws);
 599        }
 600}
 601
 602static void emit_add_line(const char *reset,
 603                          struct emit_callback *ecbdata,
 604                          const char *line, int len)
 605{
 606        emit_line_checked(reset, ecbdata, line, len,
 607                          DIFF_FILE_NEW, WSEH_NEW, '+');
 608}
 609
 610static void emit_del_line(const char *reset,
 611                          struct emit_callback *ecbdata,
 612                          const char *line, int len)
 613{
 614        emit_line_checked(reset, ecbdata, line, len,
 615                          DIFF_FILE_OLD, WSEH_OLD, '-');
 616}
 617
 618static void emit_context_line(const char *reset,
 619                              struct emit_callback *ecbdata,
 620                              const char *line, int len)
 621{
 622        emit_line_checked(reset, ecbdata, line, len,
 623                          DIFF_CONTEXT, WSEH_CONTEXT, ' ');
 624}
 625
 626static void emit_hunk_header(struct emit_callback *ecbdata,
 627                             const char *line, int len)
 628{
 629        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 630        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 631        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 632        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 633        static const char atat[2] = { '@', '@' };
 634        const char *cp, *ep;
 635        struct strbuf msgbuf = STRBUF_INIT;
 636        int org_len = len;
 637        int i = 1;
 638
 639        /*
 640         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 641         * it always is at least 10 bytes long.
 642         */
 643        if (len < 10 ||
 644            memcmp(line, atat, 2) ||
 645            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 646                emit_line(ecbdata->opt, context, reset, line, len);
 647                return;
 648        }
 649        ep += 2; /* skip over @@ */
 650
 651        /* The hunk header in fraginfo color */
 652        strbuf_addstr(&msgbuf, frag);
 653        strbuf_add(&msgbuf, line, ep - line);
 654        strbuf_addstr(&msgbuf, reset);
 655
 656        /*
 657         * trailing "\r\n"
 658         */
 659        for ( ; i < 3; i++)
 660                if (line[len - i] == '\r' || line[len - i] == '\n')
 661                        len--;
 662
 663        /* blank before the func header */
 664        for (cp = ep; ep - line < len; ep++)
 665                if (*ep != ' ' && *ep != '\t')
 666                        break;
 667        if (ep != cp) {
 668                strbuf_addstr(&msgbuf, context);
 669                strbuf_add(&msgbuf, cp, ep - cp);
 670                strbuf_addstr(&msgbuf, reset);
 671        }
 672
 673        if (ep < line + len) {
 674                strbuf_addstr(&msgbuf, func);
 675                strbuf_add(&msgbuf, ep, line + len - ep);
 676                strbuf_addstr(&msgbuf, reset);
 677        }
 678
 679        strbuf_add(&msgbuf, line + len, org_len - len);
 680        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 681        strbuf_release(&msgbuf);
 682}
 683
 684static struct diff_tempfile *claim_diff_tempfile(void) {
 685        int i;
 686        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 687                if (!diff_temp[i].name)
 688                        return diff_temp + i;
 689        die("BUG: diff is failing to clean up its tempfiles");
 690}
 691
 692static void remove_tempfile(void)
 693{
 694        int i;
 695        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 696                if (is_tempfile_active(&diff_temp[i].tempfile))
 697                        delete_tempfile(&diff_temp[i].tempfile);
 698                diff_temp[i].name = NULL;
 699        }
 700}
 701
 702static void print_line_count(FILE *file, int count)
 703{
 704        switch (count) {
 705        case 0:
 706                fprintf(file, "0,0");
 707                break;
 708        case 1:
 709                fprintf(file, "1");
 710                break;
 711        default:
 712                fprintf(file, "1,%d", count);
 713                break;
 714        }
 715}
 716
 717static void emit_rewrite_lines(struct emit_callback *ecb,
 718                               int prefix, const char *data, int size)
 719{
 720        const char *endp = NULL;
 721        static const char *nneof = " No newline at end of file\n";
 722        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 723
 724        while (0 < size) {
 725                int len;
 726
 727                endp = memchr(data, '\n', size);
 728                len = endp ? (endp - data + 1) : size;
 729                if (prefix != '+') {
 730                        ecb->lno_in_preimage++;
 731                        emit_del_line(reset, ecb, data, len);
 732                } else {
 733                        ecb->lno_in_postimage++;
 734                        emit_add_line(reset, ecb, data, len);
 735                }
 736                size -= len;
 737                data += len;
 738        }
 739        if (!endp) {
 740                const char *context = diff_get_color(ecb->color_diff,
 741                                                     DIFF_CONTEXT);
 742                putc('\n', ecb->opt->file);
 743                emit_line_0(ecb->opt, context, reset, '\\',
 744                            nneof, strlen(nneof));
 745        }
 746}
 747
 748static void emit_rewrite_diff(const char *name_a,
 749                              const char *name_b,
 750                              struct diff_filespec *one,
 751                              struct diff_filespec *two,
 752                              struct userdiff_driver *textconv_one,
 753                              struct userdiff_driver *textconv_two,
 754                              struct diff_options *o)
 755{
 756        int lc_a, lc_b;
 757        const char *name_a_tab, *name_b_tab;
 758        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 759        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 760        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 761        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 762        const char *a_prefix, *b_prefix;
 763        char *data_one, *data_two;
 764        size_t size_one, size_two;
 765        struct emit_callback ecbdata;
 766        const char *line_prefix = diff_line_prefix(o);
 767
 768        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 769                a_prefix = o->b_prefix;
 770                b_prefix = o->a_prefix;
 771        } else {
 772                a_prefix = o->a_prefix;
 773                b_prefix = o->b_prefix;
 774        }
 775
 776        name_a += (*name_a == '/');
 777        name_b += (*name_b == '/');
 778        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 779        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 780
 781        strbuf_reset(&a_name);
 782        strbuf_reset(&b_name);
 783        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 784        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 785
 786        size_one = fill_textconv(textconv_one, one, &data_one);
 787        size_two = fill_textconv(textconv_two, two, &data_two);
 788
 789        memset(&ecbdata, 0, sizeof(ecbdata));
 790        ecbdata.color_diff = want_color(o->use_color);
 791        ecbdata.ws_rule = whitespace_rule(name_b);
 792        ecbdata.opt = o;
 793        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 794                mmfile_t mf1, mf2;
 795                mf1.ptr = (char *)data_one;
 796                mf2.ptr = (char *)data_two;
 797                mf1.size = size_one;
 798                mf2.size = size_two;
 799                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 800        }
 801        ecbdata.lno_in_preimage = 1;
 802        ecbdata.lno_in_postimage = 1;
 803
 804        lc_a = count_lines(data_one, size_one);
 805        lc_b = count_lines(data_two, size_two);
 806        fprintf(o->file,
 807                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 808                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 809                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 810                line_prefix, fraginfo);
 811        if (!o->irreversible_delete)
 812                print_line_count(o->file, lc_a);
 813        else
 814                fprintf(o->file, "?,?");
 815        fprintf(o->file, " +");
 816        print_line_count(o->file, lc_b);
 817        fprintf(o->file, " @@%s\n", reset);
 818        if (lc_a && !o->irreversible_delete)
 819                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 820        if (lc_b)
 821                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 822        if (textconv_one)
 823                free((char *)data_one);
 824        if (textconv_two)
 825                free((char *)data_two);
 826}
 827
 828struct diff_words_buffer {
 829        mmfile_t text;
 830        long alloc;
 831        struct diff_words_orig {
 832                const char *begin, *end;
 833        } *orig;
 834        int orig_nr, orig_alloc;
 835};
 836
 837static void diff_words_append(char *line, unsigned long len,
 838                struct diff_words_buffer *buffer)
 839{
 840        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 841        line++;
 842        len--;
 843        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 844        buffer->text.size += len;
 845        buffer->text.ptr[buffer->text.size] = '\0';
 846}
 847
 848struct diff_words_style_elem {
 849        const char *prefix;
 850        const char *suffix;
 851        const char *color; /* NULL; filled in by the setup code if
 852                            * color is enabled */
 853};
 854
 855struct diff_words_style {
 856        enum diff_words_type type;
 857        struct diff_words_style_elem new, old, ctx;
 858        const char *newline;
 859};
 860
 861static struct diff_words_style diff_words_styles[] = {
 862        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 863        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 864        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 865};
 866
 867struct diff_words_data {
 868        struct diff_words_buffer minus, plus;
 869        const char *current_plus;
 870        int last_minus;
 871        struct diff_options *opt;
 872        regex_t *word_regex;
 873        enum diff_words_type type;
 874        struct diff_words_style *style;
 875};
 876
 877static int fn_out_diff_words_write_helper(FILE *fp,
 878                                          struct diff_words_style_elem *st_el,
 879                                          const char *newline,
 880                                          size_t count, const char *buf,
 881                                          const char *line_prefix)
 882{
 883        int print = 0;
 884
 885        while (count) {
 886                char *p = memchr(buf, '\n', count);
 887                if (print)
 888                        fputs(line_prefix, fp);
 889                if (p != buf) {
 890                        if (st_el->color && fputs(st_el->color, fp) < 0)
 891                                return -1;
 892                        if (fputs(st_el->prefix, fp) < 0 ||
 893                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 894                            fputs(st_el->suffix, fp) < 0)
 895                                return -1;
 896                        if (st_el->color && *st_el->color
 897                            && fputs(GIT_COLOR_RESET, fp) < 0)
 898                                return -1;
 899                }
 900                if (!p)
 901                        return 0;
 902                if (fputs(newline, fp) < 0)
 903                        return -1;
 904                count -= p + 1 - buf;
 905                buf = p + 1;
 906                print = 1;
 907        }
 908        return 0;
 909}
 910
 911/*
 912 * '--color-words' algorithm can be described as:
 913 *
 914 *   1. collect the minus/plus lines of a diff hunk, divided into
 915 *      minus-lines and plus-lines;
 916 *
 917 *   2. break both minus-lines and plus-lines into words and
 918 *      place them into two mmfile_t with one word for each line;
 919 *
 920 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 921 *
 922 * And for the common parts of the both file, we output the plus side text.
 923 * diff_words->current_plus is used to trace the current position of the plus file
 924 * which printed. diff_words->last_minus is used to trace the last minus word
 925 * printed.
 926 *
 927 * For '--graph' to work with '--color-words', we need to output the graph prefix
 928 * on each line of color words output. Generally, there are two conditions on
 929 * which we should output the prefix.
 930 *
 931 *   1. diff_words->last_minus == 0 &&
 932 *      diff_words->current_plus == diff_words->plus.text.ptr
 933 *
 934 *      that is: the plus text must start as a new line, and if there is no minus
 935 *      word printed, a graph prefix must be printed.
 936 *
 937 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 938 *      *(diff_words->current_plus - 1) == '\n'
 939 *
 940 *      that is: a graph prefix must be printed following a '\n'
 941 */
 942static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 943{
 944        if ((diff_words->last_minus == 0 &&
 945                diff_words->current_plus == diff_words->plus.text.ptr) ||
 946                (diff_words->current_plus > diff_words->plus.text.ptr &&
 947                *(diff_words->current_plus - 1) == '\n')) {
 948                return 1;
 949        } else {
 950                return 0;
 951        }
 952}
 953
 954static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 955{
 956        struct diff_words_data *diff_words = priv;
 957        struct diff_words_style *style = diff_words->style;
 958        int minus_first, minus_len, plus_first, plus_len;
 959        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 960        struct diff_options *opt = diff_words->opt;
 961        const char *line_prefix;
 962
 963        if (line[0] != '@' || parse_hunk_header(line, len,
 964                        &minus_first, &minus_len, &plus_first, &plus_len))
 965                return;
 966
 967        assert(opt);
 968        line_prefix = diff_line_prefix(opt);
 969
 970        /* POSIX requires that first be decremented by one if len == 0... */
 971        if (minus_len) {
 972                minus_begin = diff_words->minus.orig[minus_first].begin;
 973                minus_end =
 974                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 975        } else
 976                minus_begin = minus_end =
 977                        diff_words->minus.orig[minus_first].end;
 978
 979        if (plus_len) {
 980                plus_begin = diff_words->plus.orig[plus_first].begin;
 981                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 982        } else
 983                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 984
 985        if (color_words_output_graph_prefix(diff_words)) {
 986                fputs(line_prefix, diff_words->opt->file);
 987        }
 988        if (diff_words->current_plus != plus_begin) {
 989                fn_out_diff_words_write_helper(diff_words->opt->file,
 990                                &style->ctx, style->newline,
 991                                plus_begin - diff_words->current_plus,
 992                                diff_words->current_plus, line_prefix);
 993                if (*(plus_begin - 1) == '\n')
 994                        fputs(line_prefix, diff_words->opt->file);
 995        }
 996        if (minus_begin != minus_end) {
 997                fn_out_diff_words_write_helper(diff_words->opt->file,
 998                                &style->old, style->newline,
 999                                minus_end - minus_begin, minus_begin,
1000                                line_prefix);
1001        }
1002        if (plus_begin != plus_end) {
1003                fn_out_diff_words_write_helper(diff_words->opt->file,
1004                                &style->new, style->newline,
1005                                plus_end - plus_begin, plus_begin,
1006                                line_prefix);
1007        }
1008
1009        diff_words->current_plus = plus_end;
1010        diff_words->last_minus = minus_first;
1011}
1012
1013/* This function starts looking at *begin, and returns 0 iff a word was found. */
1014static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1015                int *begin, int *end)
1016{
1017        if (word_regex && *begin < buffer->size) {
1018                regmatch_t match[1];
1019                if (!regexec_buf(word_regex, buffer->ptr + *begin,
1020                                 buffer->size - *begin, 1, match, 0)) {
1021                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1022                                        '\n', match[0].rm_eo - match[0].rm_so);
1023                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1024                        *begin += match[0].rm_so;
1025                        return *begin >= *end;
1026                }
1027                return -1;
1028        }
1029
1030        /* find the next word */
1031        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1032                (*begin)++;
1033        if (*begin >= buffer->size)
1034                return -1;
1035
1036        /* find the end of the word */
1037        *end = *begin + 1;
1038        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1039                (*end)++;
1040
1041        return 0;
1042}
1043
1044/*
1045 * This function splits the words in buffer->text, stores the list with
1046 * newline separator into out, and saves the offsets of the original words
1047 * in buffer->orig.
1048 */
1049static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1050                regex_t *word_regex)
1051{
1052        int i, j;
1053        long alloc = 0;
1054
1055        out->size = 0;
1056        out->ptr = NULL;
1057
1058        /* fake an empty "0th" word */
1059        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1060        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1061        buffer->orig_nr = 1;
1062
1063        for (i = 0; i < buffer->text.size; i++) {
1064                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1065                        return;
1066
1067                /* store original boundaries */
1068                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1069                                buffer->orig_alloc);
1070                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1071                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1072                buffer->orig_nr++;
1073
1074                /* store one word */
1075                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1076                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1077                out->ptr[out->size + j - i] = '\n';
1078                out->size += j - i + 1;
1079
1080                i = j - 1;
1081        }
1082}
1083
1084/* this executes the word diff on the accumulated buffers */
1085static void diff_words_show(struct diff_words_data *diff_words)
1086{
1087        xpparam_t xpp;
1088        xdemitconf_t xecfg;
1089        mmfile_t minus, plus;
1090        struct diff_words_style *style = diff_words->style;
1091
1092        struct diff_options *opt = diff_words->opt;
1093        const char *line_prefix;
1094
1095        assert(opt);
1096        line_prefix = diff_line_prefix(opt);
1097
1098        /* special case: only removal */
1099        if (!diff_words->plus.text.size) {
1100                fputs(line_prefix, diff_words->opt->file);
1101                fn_out_diff_words_write_helper(diff_words->opt->file,
1102                        &style->old, style->newline,
1103                        diff_words->minus.text.size,
1104                        diff_words->minus.text.ptr, line_prefix);
1105                diff_words->minus.text.size = 0;
1106                return;
1107        }
1108
1109        diff_words->current_plus = diff_words->plus.text.ptr;
1110        diff_words->last_minus = 0;
1111
1112        memset(&xpp, 0, sizeof(xpp));
1113        memset(&xecfg, 0, sizeof(xecfg));
1114        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1115        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1116        xpp.flags = 0;
1117        /* as only the hunk header will be parsed, we need a 0-context */
1118        xecfg.ctxlen = 0;
1119        if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1120                          &xpp, &xecfg))
1121                die("unable to generate word diff");
1122        free(minus.ptr);
1123        free(plus.ptr);
1124        if (diff_words->current_plus != diff_words->plus.text.ptr +
1125                        diff_words->plus.text.size) {
1126                if (color_words_output_graph_prefix(diff_words))
1127                        fputs(line_prefix, diff_words->opt->file);
1128                fn_out_diff_words_write_helper(diff_words->opt->file,
1129                        &style->ctx, style->newline,
1130                        diff_words->plus.text.ptr + diff_words->plus.text.size
1131                        - diff_words->current_plus, diff_words->current_plus,
1132                        line_prefix);
1133        }
1134        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1135}
1136
1137/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1138static void diff_words_flush(struct emit_callback *ecbdata)
1139{
1140        if (ecbdata->diff_words->minus.text.size ||
1141            ecbdata->diff_words->plus.text.size)
1142                diff_words_show(ecbdata->diff_words);
1143}
1144
1145static void diff_filespec_load_driver(struct diff_filespec *one)
1146{
1147        /* Use already-loaded driver */
1148        if (one->driver)
1149                return;
1150
1151        if (S_ISREG(one->mode))
1152                one->driver = userdiff_find_by_path(one->path);
1153
1154        /* Fallback to default settings */
1155        if (!one->driver)
1156                one->driver = userdiff_find_by_name("default");
1157}
1158
1159static const char *userdiff_word_regex(struct diff_filespec *one)
1160{
1161        diff_filespec_load_driver(one);
1162        return one->driver->word_regex;
1163}
1164
1165static void init_diff_words_data(struct emit_callback *ecbdata,
1166                                 struct diff_options *orig_opts,
1167                                 struct diff_filespec *one,
1168                                 struct diff_filespec *two)
1169{
1170        int i;
1171        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1172        memcpy(o, orig_opts, sizeof(struct diff_options));
1173
1174        ecbdata->diff_words =
1175                xcalloc(1, sizeof(struct diff_words_data));
1176        ecbdata->diff_words->type = o->word_diff;
1177        ecbdata->diff_words->opt = o;
1178        if (!o->word_regex)
1179                o->word_regex = userdiff_word_regex(one);
1180        if (!o->word_regex)
1181                o->word_regex = userdiff_word_regex(two);
1182        if (!o->word_regex)
1183                o->word_regex = diff_word_regex_cfg;
1184        if (o->word_regex) {
1185                ecbdata->diff_words->word_regex = (regex_t *)
1186                        xmalloc(sizeof(regex_t));
1187                if (regcomp(ecbdata->diff_words->word_regex,
1188                            o->word_regex,
1189                            REG_EXTENDED | REG_NEWLINE))
1190                        die ("Invalid regular expression: %s",
1191                             o->word_regex);
1192        }
1193        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1194                if (o->word_diff == diff_words_styles[i].type) {
1195                        ecbdata->diff_words->style =
1196                                &diff_words_styles[i];
1197                        break;
1198                }
1199        }
1200        if (want_color(o->use_color)) {
1201                struct diff_words_style *st = ecbdata->diff_words->style;
1202                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1203                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1204                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1205        }
1206}
1207
1208static void free_diff_words_data(struct emit_callback *ecbdata)
1209{
1210        if (ecbdata->diff_words) {
1211                diff_words_flush(ecbdata);
1212                free (ecbdata->diff_words->opt);
1213                free (ecbdata->diff_words->minus.text.ptr);
1214                free (ecbdata->diff_words->minus.orig);
1215                free (ecbdata->diff_words->plus.text.ptr);
1216                free (ecbdata->diff_words->plus.orig);
1217                if (ecbdata->diff_words->word_regex) {
1218                        regfree(ecbdata->diff_words->word_regex);
1219                        free(ecbdata->diff_words->word_regex);
1220                }
1221                free(ecbdata->diff_words);
1222                ecbdata->diff_words = NULL;
1223        }
1224}
1225
1226const char *diff_get_color(int diff_use_color, enum color_diff ix)
1227{
1228        if (want_color(diff_use_color))
1229                return diff_colors[ix];
1230        return "";
1231}
1232
1233const char *diff_line_prefix(struct diff_options *opt)
1234{
1235        struct strbuf *msgbuf;
1236        if (!opt->output_prefix)
1237                return "";
1238
1239        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1240        return msgbuf->buf;
1241}
1242
1243static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1244{
1245        const char *cp;
1246        unsigned long allot;
1247        size_t l = len;
1248
1249        if (ecb->truncate)
1250                return ecb->truncate(line, len);
1251        cp = line;
1252        allot = l;
1253        while (0 < l) {
1254                (void) utf8_width(&cp, &l);
1255                if (!cp)
1256                        break; /* truncated in the middle? */
1257        }
1258        return allot - l;
1259}
1260
1261static void find_lno(const char *line, struct emit_callback *ecbdata)
1262{
1263        const char *p;
1264        ecbdata->lno_in_preimage = 0;
1265        ecbdata->lno_in_postimage = 0;
1266        p = strchr(line, '-');
1267        if (!p)
1268                return; /* cannot happen */
1269        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1270        p = strchr(p, '+');
1271        if (!p)
1272                return; /* cannot happen */
1273        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1274}
1275
1276static void fn_out_consume(void *priv, char *line, unsigned long len)
1277{
1278        struct emit_callback *ecbdata = priv;
1279        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1280        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1281        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1282        struct diff_options *o = ecbdata->opt;
1283        const char *line_prefix = diff_line_prefix(o);
1284
1285        o->found_changes = 1;
1286
1287        if (ecbdata->header) {
1288                fprintf(o->file, "%s", ecbdata->header->buf);
1289                strbuf_reset(ecbdata->header);
1290                ecbdata->header = NULL;
1291        }
1292
1293        if (ecbdata->label_path[0]) {
1294                const char *name_a_tab, *name_b_tab;
1295
1296                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1297                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1298
1299                fprintf(o->file, "%s%s--- %s%s%s\n",
1300                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1301                fprintf(o->file, "%s%s+++ %s%s%s\n",
1302                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1303                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1304        }
1305
1306        if (diff_suppress_blank_empty
1307            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1308                line[0] = '\n';
1309                len = 1;
1310        }
1311
1312        if (line[0] == '@') {
1313                if (ecbdata->diff_words)
1314                        diff_words_flush(ecbdata);
1315                len = sane_truncate_line(ecbdata, line, len);
1316                find_lno(line, ecbdata);
1317                emit_hunk_header(ecbdata, line, len);
1318                if (line[len-1] != '\n')
1319                        putc('\n', o->file);
1320                return;
1321        }
1322
1323        if (ecbdata->diff_words) {
1324                if (line[0] == '-') {
1325                        diff_words_append(line, len,
1326                                          &ecbdata->diff_words->minus);
1327                        return;
1328                } else if (line[0] == '+') {
1329                        diff_words_append(line, len,
1330                                          &ecbdata->diff_words->plus);
1331                        return;
1332                } else if (starts_with(line, "\\ ")) {
1333                        /*
1334                         * Eat the "no newline at eof" marker as if we
1335                         * saw a "+" or "-" line with nothing on it,
1336                         * and return without diff_words_flush() to
1337                         * defer processing. If this is the end of
1338                         * preimage, more "+" lines may come after it.
1339                         */
1340                        return;
1341                }
1342                diff_words_flush(ecbdata);
1343                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1344                        emit_line(o, context, reset, line, len);
1345                        fputs("~\n", o->file);
1346                } else {
1347                        /*
1348                         * Skip the prefix character, if any.  With
1349                         * diff_suppress_blank_empty, there may be
1350                         * none.
1351                         */
1352                        if (line[0] != '\n') {
1353                              line++;
1354                              len--;
1355                        }
1356                        emit_line(o, context, reset, line, len);
1357                }
1358                return;
1359        }
1360
1361        switch (line[0]) {
1362        case '+':
1363                ecbdata->lno_in_postimage++;
1364                emit_add_line(reset, ecbdata, line + 1, len - 1);
1365                break;
1366        case '-':
1367                ecbdata->lno_in_preimage++;
1368                emit_del_line(reset, ecbdata, line + 1, len - 1);
1369                break;
1370        case ' ':
1371                ecbdata->lno_in_postimage++;
1372                ecbdata->lno_in_preimage++;
1373                emit_context_line(reset, ecbdata, line + 1, len - 1);
1374                break;
1375        default:
1376                /* incomplete line at the end */
1377                ecbdata->lno_in_preimage++;
1378                emit_line(o, diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
1379                          reset, line, len);
1380                break;
1381        }
1382}
1383
1384static char *pprint_rename(const char *a, const char *b)
1385{
1386        const char *old = a;
1387        const char *new = b;
1388        struct strbuf name = STRBUF_INIT;
1389        int pfx_length, sfx_length;
1390        int pfx_adjust_for_slash;
1391        int len_a = strlen(a);
1392        int len_b = strlen(b);
1393        int a_midlen, b_midlen;
1394        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1395        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1396
1397        if (qlen_a || qlen_b) {
1398                quote_c_style(a, &name, NULL, 0);
1399                strbuf_addstr(&name, " => ");
1400                quote_c_style(b, &name, NULL, 0);
1401                return strbuf_detach(&name, NULL);
1402        }
1403
1404        /* Find common prefix */
1405        pfx_length = 0;
1406        while (*old && *new && *old == *new) {
1407                if (*old == '/')
1408                        pfx_length = old - a + 1;
1409                old++;
1410                new++;
1411        }
1412
1413        /* Find common suffix */
1414        old = a + len_a;
1415        new = b + len_b;
1416        sfx_length = 0;
1417        /*
1418         * If there is a common prefix, it must end in a slash.  In
1419         * that case we let this loop run 1 into the prefix to see the
1420         * same slash.
1421         *
1422         * If there is no common prefix, we cannot do this as it would
1423         * underrun the input strings.
1424         */
1425        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1426        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1427               b + pfx_length - pfx_adjust_for_slash <= new &&
1428               *old == *new) {
1429                if (*old == '/')
1430                        sfx_length = len_a - (old - a);
1431                old--;
1432                new--;
1433        }
1434
1435        /*
1436         * pfx{mid-a => mid-b}sfx
1437         * {pfx-a => pfx-b}sfx
1438         * pfx{sfx-a => sfx-b}
1439         * name-a => name-b
1440         */
1441        a_midlen = len_a - pfx_length - sfx_length;
1442        b_midlen = len_b - pfx_length - sfx_length;
1443        if (a_midlen < 0)
1444                a_midlen = 0;
1445        if (b_midlen < 0)
1446                b_midlen = 0;
1447
1448        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1449        if (pfx_length + sfx_length) {
1450                strbuf_add(&name, a, pfx_length);
1451                strbuf_addch(&name, '{');
1452        }
1453        strbuf_add(&name, a + pfx_length, a_midlen);
1454        strbuf_addstr(&name, " => ");
1455        strbuf_add(&name, b + pfx_length, b_midlen);
1456        if (pfx_length + sfx_length) {
1457                strbuf_addch(&name, '}');
1458                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1459        }
1460        return strbuf_detach(&name, NULL);
1461}
1462
1463struct diffstat_t {
1464        int nr;
1465        int alloc;
1466        struct diffstat_file {
1467                char *from_name;
1468                char *name;
1469                char *print_name;
1470                unsigned is_unmerged:1;
1471                unsigned is_binary:1;
1472                unsigned is_renamed:1;
1473                unsigned is_interesting:1;
1474                uintmax_t added, deleted;
1475        } **files;
1476};
1477
1478static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1479                                          const char *name_a,
1480                                          const char *name_b)
1481{
1482        struct diffstat_file *x;
1483        x = xcalloc(1, sizeof(*x));
1484        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1485        diffstat->files[diffstat->nr++] = x;
1486        if (name_b) {
1487                x->from_name = xstrdup(name_a);
1488                x->name = xstrdup(name_b);
1489                x->is_renamed = 1;
1490        }
1491        else {
1492                x->from_name = NULL;
1493                x->name = xstrdup(name_a);
1494        }
1495        return x;
1496}
1497
1498static void diffstat_consume(void *priv, char *line, unsigned long len)
1499{
1500        struct diffstat_t *diffstat = priv;
1501        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1502
1503        if (line[0] == '+')
1504                x->added++;
1505        else if (line[0] == '-')
1506                x->deleted++;
1507}
1508
1509const char mime_boundary_leader[] = "------------";
1510
1511static int scale_linear(int it, int width, int max_change)
1512{
1513        if (!it)
1514                return 0;
1515        /*
1516         * make sure that at least one '-' or '+' is printed if
1517         * there is any change to this path. The easiest way is to
1518         * scale linearly as if the alloted width is one column shorter
1519         * than it is, and then add 1 to the result.
1520         */
1521        return 1 + (it * (width - 1) / max_change);
1522}
1523
1524static void show_name(FILE *file,
1525                      const char *prefix, const char *name, int len)
1526{
1527        fprintf(file, " %s%-*s |", prefix, len, name);
1528}
1529
1530static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1531{
1532        if (cnt <= 0)
1533                return;
1534        fprintf(file, "%s", set);
1535        while (cnt--)
1536                putc(ch, file);
1537        fprintf(file, "%s", reset);
1538}
1539
1540static void fill_print_name(struct diffstat_file *file)
1541{
1542        char *pname;
1543
1544        if (file->print_name)
1545                return;
1546
1547        if (!file->is_renamed) {
1548                struct strbuf buf = STRBUF_INIT;
1549                if (quote_c_style(file->name, &buf, NULL, 0)) {
1550                        pname = strbuf_detach(&buf, NULL);
1551                } else {
1552                        pname = file->name;
1553                        strbuf_release(&buf);
1554                }
1555        } else {
1556                pname = pprint_rename(file->from_name, file->name);
1557        }
1558        file->print_name = pname;
1559}
1560
1561int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1562{
1563        struct strbuf sb = STRBUF_INIT;
1564        int ret;
1565
1566        if (!files) {
1567                assert(insertions == 0 && deletions == 0);
1568                return fprintf(fp, "%s\n", " 0 files changed");
1569        }
1570
1571        strbuf_addf(&sb,
1572                    (files == 1) ? " %d file changed" : " %d files changed",
1573                    files);
1574
1575        /*
1576         * For binary diff, the caller may want to print "x files
1577         * changed" with insertions == 0 && deletions == 0.
1578         *
1579         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1580         * is probably less confusing (i.e skip over "2 files changed
1581         * but nothing about added/removed lines? Is this a bug in Git?").
1582         */
1583        if (insertions || deletions == 0) {
1584                strbuf_addf(&sb,
1585                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1586                            insertions);
1587        }
1588
1589        if (deletions || insertions == 0) {
1590                strbuf_addf(&sb,
1591                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1592                            deletions);
1593        }
1594        strbuf_addch(&sb, '\n');
1595        ret = fputs(sb.buf, fp);
1596        strbuf_release(&sb);
1597        return ret;
1598}
1599
1600static void show_stats(struct diffstat_t *data, struct diff_options *options)
1601{
1602        int i, len, add, del, adds = 0, dels = 0;
1603        uintmax_t max_change = 0, max_len = 0;
1604        int total_files = data->nr, count;
1605        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1606        const char *reset, *add_c, *del_c;
1607        const char *line_prefix = "";
1608        int extra_shown = 0;
1609
1610        if (data->nr == 0)
1611                return;
1612
1613        line_prefix = diff_line_prefix(options);
1614        count = options->stat_count ? options->stat_count : data->nr;
1615
1616        reset = diff_get_color_opt(options, DIFF_RESET);
1617        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1618        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1619
1620        /*
1621         * Find the longest filename and max number of changes
1622         */
1623        for (i = 0; (i < count) && (i < data->nr); i++) {
1624                struct diffstat_file *file = data->files[i];
1625                uintmax_t change = file->added + file->deleted;
1626
1627                if (!file->is_interesting && (change == 0)) {
1628                        count++; /* not shown == room for one more */
1629                        continue;
1630                }
1631                fill_print_name(file);
1632                len = strlen(file->print_name);
1633                if (max_len < len)
1634                        max_len = len;
1635
1636                if (file->is_unmerged) {
1637                        /* "Unmerged" is 8 characters */
1638                        bin_width = bin_width < 8 ? 8 : bin_width;
1639                        continue;
1640                }
1641                if (file->is_binary) {
1642                        /* "Bin XXX -> YYY bytes" */
1643                        int w = 14 + decimal_width(file->added)
1644                                + decimal_width(file->deleted);
1645                        bin_width = bin_width < w ? w : bin_width;
1646                        /* Display change counts aligned with "Bin" */
1647                        number_width = 3;
1648                        continue;
1649                }
1650
1651                if (max_change < change)
1652                        max_change = change;
1653        }
1654        count = i; /* where we can stop scanning in data->files[] */
1655
1656        /*
1657         * We have width = stat_width or term_columns() columns total.
1658         * We want a maximum of min(max_len, stat_name_width) for the name part.
1659         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1660         * We also need 1 for " " and 4 + decimal_width(max_change)
1661         * for " | NNNN " and one the empty column at the end, altogether
1662         * 6 + decimal_width(max_change).
1663         *
1664         * If there's not enough space, we will use the smaller of
1665         * stat_name_width (if set) and 5/8*width for the filename,
1666         * and the rest for constant elements + graph part, but no more
1667         * than stat_graph_width for the graph part.
1668         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1669         * for the standard terminal size).
1670         *
1671         * In other words: stat_width limits the maximum width, and
1672         * stat_name_width fixes the maximum width of the filename,
1673         * and is also used to divide available columns if there
1674         * aren't enough.
1675         *
1676         * Binary files are displayed with "Bin XXX -> YYY bytes"
1677         * instead of the change count and graph. This part is treated
1678         * similarly to the graph part, except that it is not
1679         * "scaled". If total width is too small to accommodate the
1680         * guaranteed minimum width of the filename part and the
1681         * separators and this message, this message will "overflow"
1682         * making the line longer than the maximum width.
1683         */
1684
1685        if (options->stat_width == -1)
1686                width = term_columns() - strlen(line_prefix);
1687        else
1688                width = options->stat_width ? options->stat_width : 80;
1689        number_width = decimal_width(max_change) > number_width ?
1690                decimal_width(max_change) : number_width;
1691
1692        if (options->stat_graph_width == -1)
1693                options->stat_graph_width = diff_stat_graph_width;
1694
1695        /*
1696         * Guarantee 3/8*16==6 for the graph part
1697         * and 5/8*16==10 for the filename part
1698         */
1699        if (width < 16 + 6 + number_width)
1700                width = 16 + 6 + number_width;
1701
1702        /*
1703         * First assign sizes that are wanted, ignoring available width.
1704         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1705         * starting from "XXX" should fit in graph_width.
1706         */
1707        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1708        if (options->stat_graph_width &&
1709            options->stat_graph_width < graph_width)
1710                graph_width = options->stat_graph_width;
1711
1712        name_width = (options->stat_name_width > 0 &&
1713                      options->stat_name_width < max_len) ?
1714                options->stat_name_width : max_len;
1715
1716        /*
1717         * Adjust adjustable widths not to exceed maximum width
1718         */
1719        if (name_width + number_width + 6 + graph_width > width) {
1720                if (graph_width > width * 3/8 - number_width - 6) {
1721                        graph_width = width * 3/8 - number_width - 6;
1722                        if (graph_width < 6)
1723                                graph_width = 6;
1724                }
1725
1726                if (options->stat_graph_width &&
1727                    graph_width > options->stat_graph_width)
1728                        graph_width = options->stat_graph_width;
1729                if (name_width > width - number_width - 6 - graph_width)
1730                        name_width = width - number_width - 6 - graph_width;
1731                else
1732                        graph_width = width - number_width - 6 - name_width;
1733        }
1734
1735        /*
1736         * From here name_width is the width of the name area,
1737         * and graph_width is the width of the graph area.
1738         * max_change is used to scale graph properly.
1739         */
1740        for (i = 0; i < count; i++) {
1741                const char *prefix = "";
1742                struct diffstat_file *file = data->files[i];
1743                char *name = file->print_name;
1744                uintmax_t added = file->added;
1745                uintmax_t deleted = file->deleted;
1746                int name_len;
1747
1748                if (!file->is_interesting && (added + deleted == 0))
1749                        continue;
1750
1751                /*
1752                 * "scale" the filename
1753                 */
1754                len = name_width;
1755                name_len = strlen(name);
1756                if (name_width < name_len) {
1757                        char *slash;
1758                        prefix = "...";
1759                        len -= 3;
1760                        name += name_len - len;
1761                        slash = strchr(name, '/');
1762                        if (slash)
1763                                name = slash;
1764                }
1765
1766                if (file->is_binary) {
1767                        fprintf(options->file, "%s", line_prefix);
1768                        show_name(options->file, prefix, name, len);
1769                        fprintf(options->file, " %*s", number_width, "Bin");
1770                        if (!added && !deleted) {
1771                                putc('\n', options->file);
1772                                continue;
1773                        }
1774                        fprintf(options->file, " %s%"PRIuMAX"%s",
1775                                del_c, deleted, reset);
1776                        fprintf(options->file, " -> ");
1777                        fprintf(options->file, "%s%"PRIuMAX"%s",
1778                                add_c, added, reset);
1779                        fprintf(options->file, " bytes");
1780                        fprintf(options->file, "\n");
1781                        continue;
1782                }
1783                else if (file->is_unmerged) {
1784                        fprintf(options->file, "%s", line_prefix);
1785                        show_name(options->file, prefix, name, len);
1786                        fprintf(options->file, " Unmerged\n");
1787                        continue;
1788                }
1789
1790                /*
1791                 * scale the add/delete
1792                 */
1793                add = added;
1794                del = deleted;
1795
1796                if (graph_width <= max_change) {
1797                        int total = scale_linear(add + del, graph_width, max_change);
1798                        if (total < 2 && add && del)
1799                                /* width >= 2 due to the sanity check */
1800                                total = 2;
1801                        if (add < del) {
1802                                add = scale_linear(add, graph_width, max_change);
1803                                del = total - add;
1804                        } else {
1805                                del = scale_linear(del, graph_width, max_change);
1806                                add = total - del;
1807                        }
1808                }
1809                fprintf(options->file, "%s", line_prefix);
1810                show_name(options->file, prefix, name, len);
1811                fprintf(options->file, " %*"PRIuMAX"%s",
1812                        number_width, added + deleted,
1813                        added + deleted ? " " : "");
1814                show_graph(options->file, '+', add, add_c, reset);
1815                show_graph(options->file, '-', del, del_c, reset);
1816                fprintf(options->file, "\n");
1817        }
1818
1819        for (i = 0; i < data->nr; i++) {
1820                struct diffstat_file *file = data->files[i];
1821                uintmax_t added = file->added;
1822                uintmax_t deleted = file->deleted;
1823
1824                if (file->is_unmerged ||
1825                    (!file->is_interesting && (added + deleted == 0))) {
1826                        total_files--;
1827                        continue;
1828                }
1829
1830                if (!file->is_binary) {
1831                        adds += added;
1832                        dels += deleted;
1833                }
1834                if (i < count)
1835                        continue;
1836                if (!extra_shown)
1837                        fprintf(options->file, "%s ...\n", line_prefix);
1838                extra_shown = 1;
1839        }
1840        fprintf(options->file, "%s", line_prefix);
1841        print_stat_summary(options->file, total_files, adds, dels);
1842}
1843
1844static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1845{
1846        int i, adds = 0, dels = 0, total_files = data->nr;
1847
1848        if (data->nr == 0)
1849                return;
1850
1851        for (i = 0; i < data->nr; i++) {
1852                int added = data->files[i]->added;
1853                int deleted= data->files[i]->deleted;
1854
1855                if (data->files[i]->is_unmerged ||
1856                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1857                        total_files--;
1858                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1859                        adds += added;
1860                        dels += deleted;
1861                }
1862        }
1863        fprintf(options->file, "%s", diff_line_prefix(options));
1864        print_stat_summary(options->file, total_files, adds, dels);
1865}
1866
1867static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1868{
1869        int i;
1870
1871        if (data->nr == 0)
1872                return;
1873
1874        for (i = 0; i < data->nr; i++) {
1875                struct diffstat_file *file = data->files[i];
1876
1877                fprintf(options->file, "%s", diff_line_prefix(options));
1878
1879                if (file->is_binary)
1880                        fprintf(options->file, "-\t-\t");
1881                else
1882                        fprintf(options->file,
1883                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1884                                file->added, file->deleted);
1885                if (options->line_termination) {
1886                        fill_print_name(file);
1887                        if (!file->is_renamed)
1888                                write_name_quoted(file->name, options->file,
1889                                                  options->line_termination);
1890                        else {
1891                                fputs(file->print_name, options->file);
1892                                putc(options->line_termination, options->file);
1893                        }
1894                } else {
1895                        if (file->is_renamed) {
1896                                putc('\0', options->file);
1897                                write_name_quoted(file->from_name, options->file, '\0');
1898                        }
1899                        write_name_quoted(file->name, options->file, '\0');
1900                }
1901        }
1902}
1903
1904struct dirstat_file {
1905        const char *name;
1906        unsigned long changed;
1907};
1908
1909struct dirstat_dir {
1910        struct dirstat_file *files;
1911        int alloc, nr, permille, cumulative;
1912};
1913
1914static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1915                unsigned long changed, const char *base, int baselen)
1916{
1917        unsigned long this_dir = 0;
1918        unsigned int sources = 0;
1919        const char *line_prefix = diff_line_prefix(opt);
1920
1921        while (dir->nr) {
1922                struct dirstat_file *f = dir->files;
1923                int namelen = strlen(f->name);
1924                unsigned long this;
1925                char *slash;
1926
1927                if (namelen < baselen)
1928                        break;
1929                if (memcmp(f->name, base, baselen))
1930                        break;
1931                slash = strchr(f->name + baselen, '/');
1932                if (slash) {
1933                        int newbaselen = slash + 1 - f->name;
1934                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1935                        sources++;
1936                } else {
1937                        this = f->changed;
1938                        dir->files++;
1939                        dir->nr--;
1940                        sources += 2;
1941                }
1942                this_dir += this;
1943        }
1944
1945        /*
1946         * We don't report dirstat's for
1947         *  - the top level
1948         *  - or cases where everything came from a single directory
1949         *    under this directory (sources == 1).
1950         */
1951        if (baselen && sources != 1) {
1952                if (this_dir) {
1953                        int permille = this_dir * 1000 / changed;
1954                        if (permille >= dir->permille) {
1955                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1956                                        permille / 10, permille % 10, baselen, base);
1957                                if (!dir->cumulative)
1958                                        return 0;
1959                        }
1960                }
1961        }
1962        return this_dir;
1963}
1964
1965static int dirstat_compare(const void *_a, const void *_b)
1966{
1967        const struct dirstat_file *a = _a;
1968        const struct dirstat_file *b = _b;
1969        return strcmp(a->name, b->name);
1970}
1971
1972static void show_dirstat(struct diff_options *options)
1973{
1974        int i;
1975        unsigned long changed;
1976        struct dirstat_dir dir;
1977        struct diff_queue_struct *q = &diff_queued_diff;
1978
1979        dir.files = NULL;
1980        dir.alloc = 0;
1981        dir.nr = 0;
1982        dir.permille = options->dirstat_permille;
1983        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1984
1985        changed = 0;
1986        for (i = 0; i < q->nr; i++) {
1987                struct diff_filepair *p = q->queue[i];
1988                const char *name;
1989                unsigned long copied, added, damage;
1990                int content_changed;
1991
1992                name = p->two->path ? p->two->path : p->one->path;
1993
1994                if (p->one->oid_valid && p->two->oid_valid)
1995                        content_changed = oidcmp(&p->one->oid, &p->two->oid);
1996                else
1997                        content_changed = 1;
1998
1999                if (!content_changed) {
2000                        /*
2001                         * The SHA1 has not changed, so pre-/post-content is
2002                         * identical. We can therefore skip looking at the
2003                         * file contents altogether.
2004                         */
2005                        damage = 0;
2006                        goto found_damage;
2007                }
2008
2009                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
2010                        /*
2011                         * In --dirstat-by-file mode, we don't really need to
2012                         * look at the actual file contents at all.
2013                         * The fact that the SHA1 changed is enough for us to
2014                         * add this file to the list of results
2015                         * (with each file contributing equal damage).
2016                         */
2017                        damage = 1;
2018                        goto found_damage;
2019                }
2020
2021                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2022                        diff_populate_filespec(p->one, 0);
2023                        diff_populate_filespec(p->two, 0);
2024                        diffcore_count_changes(p->one, p->two, NULL, NULL,
2025                                               &copied, &added);
2026                        diff_free_filespec_data(p->one);
2027                        diff_free_filespec_data(p->two);
2028                } else if (DIFF_FILE_VALID(p->one)) {
2029                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2030                        copied = added = 0;
2031                        diff_free_filespec_data(p->one);
2032                } else if (DIFF_FILE_VALID(p->two)) {
2033                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2034                        copied = 0;
2035                        added = p->two->size;
2036                        diff_free_filespec_data(p->two);
2037                } else
2038                        continue;
2039
2040                /*
2041                 * Original minus copied is the removed material,
2042                 * added is the new material.  They are both damages
2043                 * made to the preimage.
2044                 * If the resulting damage is zero, we know that
2045                 * diffcore_count_changes() considers the two entries to
2046                 * be identical, but since content_changed is true, we
2047                 * know that there must have been _some_ kind of change,
2048                 * so we force all entries to have damage > 0.
2049                 */
2050                damage = (p->one->size - copied) + added;
2051                if (!damage)
2052                        damage = 1;
2053
2054found_damage:
2055                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2056                dir.files[dir.nr].name = name;
2057                dir.files[dir.nr].changed = damage;
2058                changed += damage;
2059                dir.nr++;
2060        }
2061
2062        /* This can happen even with many files, if everything was renames */
2063        if (!changed)
2064                return;
2065
2066        /* Show all directories with more than x% of the changes */
2067        QSORT(dir.files, dir.nr, dirstat_compare);
2068        gather_dirstat(options, &dir, changed, "", 0);
2069}
2070
2071static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2072{
2073        int i;
2074        unsigned long changed;
2075        struct dirstat_dir dir;
2076
2077        if (data->nr == 0)
2078                return;
2079
2080        dir.files = NULL;
2081        dir.alloc = 0;
2082        dir.nr = 0;
2083        dir.permille = options->dirstat_permille;
2084        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2085
2086        changed = 0;
2087        for (i = 0; i < data->nr; i++) {
2088                struct diffstat_file *file = data->files[i];
2089                unsigned long damage = file->added + file->deleted;
2090                if (file->is_binary)
2091                        /*
2092                         * binary files counts bytes, not lines. Must find some
2093                         * way to normalize binary bytes vs. textual lines.
2094                         * The following heuristic assumes that there are 64
2095                         * bytes per "line".
2096                         * This is stupid and ugly, but very cheap...
2097                         */
2098                        damage = (damage + 63) / 64;
2099                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2100                dir.files[dir.nr].name = file->name;
2101                dir.files[dir.nr].changed = damage;
2102                changed += damage;
2103                dir.nr++;
2104        }
2105
2106        /* This can happen even with many files, if everything was renames */
2107        if (!changed)
2108                return;
2109
2110        /* Show all directories with more than x% of the changes */
2111        QSORT(dir.files, dir.nr, dirstat_compare);
2112        gather_dirstat(options, &dir, changed, "", 0);
2113}
2114
2115static void free_diffstat_info(struct diffstat_t *diffstat)
2116{
2117        int i;
2118        for (i = 0; i < diffstat->nr; i++) {
2119                struct diffstat_file *f = diffstat->files[i];
2120                if (f->name != f->print_name)
2121                        free(f->print_name);
2122                free(f->name);
2123                free(f->from_name);
2124                free(f);
2125        }
2126        free(diffstat->files);
2127}
2128
2129struct checkdiff_t {
2130        const char *filename;
2131        int lineno;
2132        int conflict_marker_size;
2133        struct diff_options *o;
2134        unsigned ws_rule;
2135        unsigned status;
2136};
2137
2138static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2139{
2140        char firstchar;
2141        int cnt;
2142
2143        if (len < marker_size + 1)
2144                return 0;
2145        firstchar = line[0];
2146        switch (firstchar) {
2147        case '=': case '>': case '<': case '|':
2148                break;
2149        default:
2150                return 0;
2151        }
2152        for (cnt = 1; cnt < marker_size; cnt++)
2153                if (line[cnt] != firstchar)
2154                        return 0;
2155        /* line[1] thru line[marker_size-1] are same as firstchar */
2156        if (len < marker_size + 1 || !isspace(line[marker_size]))
2157                return 0;
2158        return 1;
2159}
2160
2161static void checkdiff_consume(void *priv, char *line, unsigned long len)
2162{
2163        struct checkdiff_t *data = priv;
2164        int marker_size = data->conflict_marker_size;
2165        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2166        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2167        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2168        char *err;
2169        const char *line_prefix;
2170
2171        assert(data->o);
2172        line_prefix = diff_line_prefix(data->o);
2173
2174        if (line[0] == '+') {
2175                unsigned bad;
2176                data->lineno++;
2177                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2178                        data->status |= 1;
2179                        fprintf(data->o->file,
2180                                "%s%s:%d: leftover conflict marker\n",
2181                                line_prefix, data->filename, data->lineno);
2182                }
2183                bad = ws_check(line + 1, len - 1, data->ws_rule);
2184                if (!bad)
2185                        return;
2186                data->status |= bad;
2187                err = whitespace_error_string(bad);
2188                fprintf(data->o->file, "%s%s:%d: %s.\n",
2189                        line_prefix, data->filename, data->lineno, err);
2190                free(err);
2191                emit_line(data->o, set, reset, line, 1);
2192                ws_check_emit(line + 1, len - 1, data->ws_rule,
2193                              data->o->file, set, reset, ws);
2194        } else if (line[0] == ' ') {
2195                data->lineno++;
2196        } else if (line[0] == '@') {
2197                char *plus = strchr(line, '+');
2198                if (plus)
2199                        data->lineno = strtol(plus, NULL, 10) - 1;
2200                else
2201                        die("invalid diff");
2202        }
2203}
2204
2205static unsigned char *deflate_it(char *data,
2206                                 unsigned long size,
2207                                 unsigned long *result_size)
2208{
2209        int bound;
2210        unsigned char *deflated;
2211        git_zstream stream;
2212
2213        git_deflate_init(&stream, zlib_compression_level);
2214        bound = git_deflate_bound(&stream, size);
2215        deflated = xmalloc(bound);
2216        stream.next_out = deflated;
2217        stream.avail_out = bound;
2218
2219        stream.next_in = (unsigned char *)data;
2220        stream.avail_in = size;
2221        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2222                ; /* nothing */
2223        git_deflate_end(&stream);
2224        *result_size = stream.total_out;
2225        return deflated;
2226}
2227
2228static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2229                                  const char *prefix)
2230{
2231        void *cp;
2232        void *delta;
2233        void *deflated;
2234        void *data;
2235        unsigned long orig_size;
2236        unsigned long delta_size;
2237        unsigned long deflate_size;
2238        unsigned long data_size;
2239
2240        /* We could do deflated delta, or we could do just deflated two,
2241         * whichever is smaller.
2242         */
2243        delta = NULL;
2244        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2245        if (one->size && two->size) {
2246                delta = diff_delta(one->ptr, one->size,
2247                                   two->ptr, two->size,
2248                                   &delta_size, deflate_size);
2249                if (delta) {
2250                        void *to_free = delta;
2251                        orig_size = delta_size;
2252                        delta = deflate_it(delta, delta_size, &delta_size);
2253                        free(to_free);
2254                }
2255        }
2256
2257        if (delta && delta_size < deflate_size) {
2258                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2259                free(deflated);
2260                data = delta;
2261                data_size = delta_size;
2262        }
2263        else {
2264                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2265                free(delta);
2266                data = deflated;
2267                data_size = deflate_size;
2268        }
2269
2270        /* emit data encoded in base85 */
2271        cp = data;
2272        while (data_size) {
2273                int bytes = (52 < data_size) ? 52 : data_size;
2274                char line[70];
2275                data_size -= bytes;
2276                if (bytes <= 26)
2277                        line[0] = bytes + 'A' - 1;
2278                else
2279                        line[0] = bytes - 26 + 'a' - 1;
2280                encode_85(line + 1, cp, bytes);
2281                cp = (char *) cp + bytes;
2282                fprintf(file, "%s", prefix);
2283                fputs(line, file);
2284                fputc('\n', file);
2285        }
2286        fprintf(file, "%s\n", prefix);
2287        free(data);
2288}
2289
2290static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2291                             const char *prefix)
2292{
2293        fprintf(file, "%sGIT binary patch\n", prefix);
2294        emit_binary_diff_body(file, one, two, prefix);
2295        emit_binary_diff_body(file, two, one, prefix);
2296}
2297
2298int diff_filespec_is_binary(struct diff_filespec *one)
2299{
2300        if (one->is_binary == -1) {
2301                diff_filespec_load_driver(one);
2302                if (one->driver->binary != -1)
2303                        one->is_binary = one->driver->binary;
2304                else {
2305                        if (!one->data && DIFF_FILE_VALID(one))
2306                                diff_populate_filespec(one, CHECK_BINARY);
2307                        if (one->is_binary == -1 && one->data)
2308                                one->is_binary = buffer_is_binary(one->data,
2309                                                one->size);
2310                        if (one->is_binary == -1)
2311                                one->is_binary = 0;
2312                }
2313        }
2314        return one->is_binary;
2315}
2316
2317static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2318{
2319        diff_filespec_load_driver(one);
2320        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2321}
2322
2323void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2324{
2325        if (!options->a_prefix)
2326                options->a_prefix = a;
2327        if (!options->b_prefix)
2328                options->b_prefix = b;
2329}
2330
2331struct userdiff_driver *get_textconv(struct diff_filespec *one)
2332{
2333        if (!DIFF_FILE_VALID(one))
2334                return NULL;
2335
2336        diff_filespec_load_driver(one);
2337        return userdiff_get_textconv(one->driver);
2338}
2339
2340static void builtin_diff(const char *name_a,
2341                         const char *name_b,
2342                         struct diff_filespec *one,
2343                         struct diff_filespec *two,
2344                         const char *xfrm_msg,
2345                         int must_show_header,
2346                         struct diff_options *o,
2347                         int complete_rewrite)
2348{
2349        mmfile_t mf1, mf2;
2350        const char *lbl[2];
2351        char *a_one, *b_two;
2352        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2353        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2354        const char *a_prefix, *b_prefix;
2355        struct userdiff_driver *textconv_one = NULL;
2356        struct userdiff_driver *textconv_two = NULL;
2357        struct strbuf header = STRBUF_INIT;
2358        const char *line_prefix = diff_line_prefix(o);
2359
2360        diff_set_mnemonic_prefix(o, "a/", "b/");
2361        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2362                a_prefix = o->b_prefix;
2363                b_prefix = o->a_prefix;
2364        } else {
2365                a_prefix = o->a_prefix;
2366                b_prefix = o->b_prefix;
2367        }
2368
2369        if (o->submodule_format == DIFF_SUBMODULE_LOG &&
2370            (!one->mode || S_ISGITLINK(one->mode)) &&
2371            (!two->mode || S_ISGITLINK(two->mode))) {
2372                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2373                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2374                show_submodule_summary(o->file, one->path ? one->path : two->path,
2375                                line_prefix,
2376                                &one->oid, &two->oid,
2377                                two->dirty_submodule,
2378                                meta, del, add, reset);
2379                return;
2380        } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
2381                   (!one->mode || S_ISGITLINK(one->mode)) &&
2382                   (!two->mode || S_ISGITLINK(two->mode))) {
2383                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2384                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2385                show_submodule_inline_diff(o->file, one->path ? one->path : two->path,
2386                                line_prefix,
2387                                &one->oid, &two->oid,
2388                                two->dirty_submodule,
2389                                meta, del, add, reset, o);
2390                return;
2391        }
2392
2393        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2394                textconv_one = get_textconv(one);
2395                textconv_two = get_textconv(two);
2396        }
2397
2398        /* Never use a non-valid filename anywhere if at all possible */
2399        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2400        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2401
2402        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2403        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2404        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2405        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2406        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2407        if (lbl[0][0] == '/') {
2408                /* /dev/null */
2409                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2410                if (xfrm_msg)
2411                        strbuf_addstr(&header, xfrm_msg);
2412                must_show_header = 1;
2413        }
2414        else if (lbl[1][0] == '/') {
2415                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2416                if (xfrm_msg)
2417                        strbuf_addstr(&header, xfrm_msg);
2418                must_show_header = 1;
2419        }
2420        else {
2421                if (one->mode != two->mode) {
2422                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2423                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2424                        must_show_header = 1;
2425                }
2426                if (xfrm_msg)
2427                        strbuf_addstr(&header, xfrm_msg);
2428
2429                /*
2430                 * we do not run diff between different kind
2431                 * of objects.
2432                 */
2433                if ((one->mode ^ two->mode) & S_IFMT)
2434                        goto free_ab_and_return;
2435                if (complete_rewrite &&
2436                    (textconv_one || !diff_filespec_is_binary(one)) &&
2437                    (textconv_two || !diff_filespec_is_binary(two))) {
2438                        fprintf(o->file, "%s", header.buf);
2439                        strbuf_reset(&header);
2440                        emit_rewrite_diff(name_a, name_b, one, two,
2441                                                textconv_one, textconv_two, o);
2442                        o->found_changes = 1;
2443                        goto free_ab_and_return;
2444                }
2445        }
2446
2447        if (o->irreversible_delete && lbl[1][0] == '/') {
2448                fprintf(o->file, "%s", header.buf);
2449                strbuf_reset(&header);
2450                goto free_ab_and_return;
2451        } else if (!DIFF_OPT_TST(o, TEXT) &&
2452            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2453              (!textconv_two && diff_filespec_is_binary(two)) )) {
2454                if (!one->data && !two->data &&
2455                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2456                    !DIFF_OPT_TST(o, BINARY)) {
2457                        if (!oidcmp(&one->oid, &two->oid)) {
2458                                if (must_show_header)
2459                                        fprintf(o->file, "%s", header.buf);
2460                                goto free_ab_and_return;
2461                        }
2462                        fprintf(o->file, "%s", header.buf);
2463                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2464                                line_prefix, lbl[0], lbl[1]);
2465                        goto free_ab_and_return;
2466                }
2467                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2468                        die("unable to read files to diff");
2469                /* Quite common confusing case */
2470                if (mf1.size == mf2.size &&
2471                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2472                        if (must_show_header)
2473                                fprintf(o->file, "%s", header.buf);
2474                        goto free_ab_and_return;
2475                }
2476                fprintf(o->file, "%s", header.buf);
2477                strbuf_reset(&header);
2478                if (DIFF_OPT_TST(o, BINARY))
2479                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2480                else
2481                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2482                                line_prefix, lbl[0], lbl[1]);
2483                o->found_changes = 1;
2484        } else {
2485                /* Crazy xdl interfaces.. */
2486                const char *diffopts = getenv("GIT_DIFF_OPTS");
2487                const char *v;
2488                xpparam_t xpp;
2489                xdemitconf_t xecfg;
2490                struct emit_callback ecbdata;
2491                const struct userdiff_funcname *pe;
2492
2493                if (must_show_header) {
2494                        fprintf(o->file, "%s", header.buf);
2495                        strbuf_reset(&header);
2496                }
2497
2498                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2499                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2500
2501                pe = diff_funcname_pattern(one);
2502                if (!pe)
2503                        pe = diff_funcname_pattern(two);
2504
2505                memset(&xpp, 0, sizeof(xpp));
2506                memset(&xecfg, 0, sizeof(xecfg));
2507                memset(&ecbdata, 0, sizeof(ecbdata));
2508                ecbdata.label_path = lbl;
2509                ecbdata.color_diff = want_color(o->use_color);
2510                ecbdata.ws_rule = whitespace_rule(name_b);
2511                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2512                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2513                ecbdata.opt = o;
2514                ecbdata.header = header.len ? &header : NULL;
2515                xpp.flags = o->xdl_opts;
2516                xecfg.ctxlen = o->context;
2517                xecfg.interhunkctxlen = o->interhunkcontext;
2518                xecfg.flags = XDL_EMIT_FUNCNAMES;
2519                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2520                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2521                if (pe)
2522                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2523                if (!diffopts)
2524                        ;
2525                else if (skip_prefix(diffopts, "--unified=", &v))
2526                        xecfg.ctxlen = strtoul(v, NULL, 10);
2527                else if (skip_prefix(diffopts, "-u", &v))
2528                        xecfg.ctxlen = strtoul(v, NULL, 10);
2529                if (o->word_diff)
2530                        init_diff_words_data(&ecbdata, o, one, two);
2531                if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2532                                  &xpp, &xecfg))
2533                        die("unable to generate diff for %s", one->path);
2534                if (o->word_diff)
2535                        free_diff_words_data(&ecbdata);
2536                if (textconv_one)
2537                        free(mf1.ptr);
2538                if (textconv_two)
2539                        free(mf2.ptr);
2540                xdiff_clear_find_func(&xecfg);
2541        }
2542
2543 free_ab_and_return:
2544        strbuf_release(&header);
2545        diff_free_filespec_data(one);
2546        diff_free_filespec_data(two);
2547        free(a_one);
2548        free(b_two);
2549        return;
2550}
2551
2552static void builtin_diffstat(const char *name_a, const char *name_b,
2553                             struct diff_filespec *one,
2554                             struct diff_filespec *two,
2555                             struct diffstat_t *diffstat,
2556                             struct diff_options *o,
2557                             struct diff_filepair *p)
2558{
2559        mmfile_t mf1, mf2;
2560        struct diffstat_file *data;
2561        int same_contents;
2562        int complete_rewrite = 0;
2563
2564        if (!DIFF_PAIR_UNMERGED(p)) {
2565                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2566                        complete_rewrite = 1;
2567        }
2568
2569        data = diffstat_add(diffstat, name_a, name_b);
2570        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2571
2572        if (!one || !two) {
2573                data->is_unmerged = 1;
2574                return;
2575        }
2576
2577        same_contents = !oidcmp(&one->oid, &two->oid);
2578
2579        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2580                data->is_binary = 1;
2581                if (same_contents) {
2582                        data->added = 0;
2583                        data->deleted = 0;
2584                } else {
2585                        data->added = diff_filespec_size(two);
2586                        data->deleted = diff_filespec_size(one);
2587                }
2588        }
2589
2590        else if (complete_rewrite) {
2591                diff_populate_filespec(one, 0);
2592                diff_populate_filespec(two, 0);
2593                data->deleted = count_lines(one->data, one->size);
2594                data->added = count_lines(two->data, two->size);
2595        }
2596
2597        else if (!same_contents) {
2598                /* Crazy xdl interfaces.. */
2599                xpparam_t xpp;
2600                xdemitconf_t xecfg;
2601
2602                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2603                        die("unable to read files to diff");
2604
2605                memset(&xpp, 0, sizeof(xpp));
2606                memset(&xecfg, 0, sizeof(xecfg));
2607                xpp.flags = o->xdl_opts;
2608                xecfg.ctxlen = o->context;
2609                xecfg.interhunkctxlen = o->interhunkcontext;
2610                if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2611                                  &xpp, &xecfg))
2612                        die("unable to generate diffstat for %s", one->path);
2613        }
2614
2615        diff_free_filespec_data(one);
2616        diff_free_filespec_data(two);
2617}
2618
2619static void builtin_checkdiff(const char *name_a, const char *name_b,
2620                              const char *attr_path,
2621                              struct diff_filespec *one,
2622                              struct diff_filespec *two,
2623                              struct diff_options *o)
2624{
2625        mmfile_t mf1, mf2;
2626        struct checkdiff_t data;
2627
2628        if (!two)
2629                return;
2630
2631        memset(&data, 0, sizeof(data));
2632        data.filename = name_b ? name_b : name_a;
2633        data.lineno = 0;
2634        data.o = o;
2635        data.ws_rule = whitespace_rule(attr_path);
2636        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2637
2638        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2639                die("unable to read files to diff");
2640
2641        /*
2642         * All the other codepaths check both sides, but not checking
2643         * the "old" side here is deliberate.  We are checking the newly
2644         * introduced changes, and as long as the "new" side is text, we
2645         * can and should check what it introduces.
2646         */
2647        if (diff_filespec_is_binary(two))
2648                goto free_and_return;
2649        else {
2650                /* Crazy xdl interfaces.. */
2651                xpparam_t xpp;
2652                xdemitconf_t xecfg;
2653
2654                memset(&xpp, 0, sizeof(xpp));
2655                memset(&xecfg, 0, sizeof(xecfg));
2656                xecfg.ctxlen = 1; /* at least one context line */
2657                xpp.flags = 0;
2658                if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2659                                  &xpp, &xecfg))
2660                        die("unable to generate checkdiff for %s", one->path);
2661
2662                if (data.ws_rule & WS_BLANK_AT_EOF) {
2663                        struct emit_callback ecbdata;
2664                        int blank_at_eof;
2665
2666                        ecbdata.ws_rule = data.ws_rule;
2667                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2668                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2669
2670                        if (blank_at_eof) {
2671                                static char *err;
2672                                if (!err)
2673                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2674                                fprintf(o->file, "%s:%d: %s.\n",
2675                                        data.filename, blank_at_eof, err);
2676                                data.status = 1; /* report errors */
2677                        }
2678                }
2679        }
2680 free_and_return:
2681        diff_free_filespec_data(one);
2682        diff_free_filespec_data(two);
2683        if (data.status)
2684                DIFF_OPT_SET(o, CHECK_FAILED);
2685}
2686
2687struct diff_filespec *alloc_filespec(const char *path)
2688{
2689        struct diff_filespec *spec;
2690
2691        FLEXPTR_ALLOC_STR(spec, path, path);
2692        spec->count = 1;
2693        spec->is_binary = -1;
2694        return spec;
2695}
2696
2697void free_filespec(struct diff_filespec *spec)
2698{
2699        if (!--spec->count) {
2700                diff_free_filespec_data(spec);
2701                free(spec);
2702        }
2703}
2704
2705void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2706                   int sha1_valid, unsigned short mode)
2707{
2708        if (mode) {
2709                spec->mode = canon_mode(mode);
2710                hashcpy(spec->oid.hash, sha1);
2711                spec->oid_valid = sha1_valid;
2712        }
2713}
2714
2715/*
2716 * Given a name and sha1 pair, if the index tells us the file in
2717 * the work tree has that object contents, return true, so that
2718 * prepare_temp_file() does not have to inflate and extract.
2719 */
2720static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2721{
2722        const struct cache_entry *ce;
2723        struct stat st;
2724        int pos, len;
2725
2726        /*
2727         * We do not read the cache ourselves here, because the
2728         * benchmark with my previous version that always reads cache
2729         * shows that it makes things worse for diff-tree comparing
2730         * two linux-2.6 kernel trees in an already checked out work
2731         * tree.  This is because most diff-tree comparisons deal with
2732         * only a small number of files, while reading the cache is
2733         * expensive for a large project, and its cost outweighs the
2734         * savings we get by not inflating the object to a temporary
2735         * file.  Practically, this code only helps when we are used
2736         * by diff-cache --cached, which does read the cache before
2737         * calling us.
2738         */
2739        if (!active_cache)
2740                return 0;
2741
2742        /* We want to avoid the working directory if our caller
2743         * doesn't need the data in a normal file, this system
2744         * is rather slow with its stat/open/mmap/close syscalls,
2745         * and the object is contained in a pack file.  The pack
2746         * is probably already open and will be faster to obtain
2747         * the data through than the working directory.  Loose
2748         * objects however would tend to be slower as they need
2749         * to be individually opened and inflated.
2750         */
2751        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2752                return 0;
2753
2754        /*
2755         * Similarly, if we'd have to convert the file contents anyway, that
2756         * makes the optimization not worthwhile.
2757         */
2758        if (!want_file && would_convert_to_git(name))
2759                return 0;
2760
2761        len = strlen(name);
2762        pos = cache_name_pos(name, len);
2763        if (pos < 0)
2764                return 0;
2765        ce = active_cache[pos];
2766
2767        /*
2768         * This is not the sha1 we are looking for, or
2769         * unreusable because it is not a regular file.
2770         */
2771        if (hashcmp(sha1, ce->oid.hash) || !S_ISREG(ce->ce_mode))
2772                return 0;
2773
2774        /*
2775         * If ce is marked as "assume unchanged", there is no
2776         * guarantee that work tree matches what we are looking for.
2777         */
2778        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2779                return 0;
2780
2781        /*
2782         * If ce matches the file in the work tree, we can reuse it.
2783         */
2784        if (ce_uptodate(ce) ||
2785            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2786                return 1;
2787
2788        return 0;
2789}
2790
2791static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2792{
2793        struct strbuf buf = STRBUF_INIT;
2794        char *dirty = "";
2795
2796        /* Are we looking at the work tree? */
2797        if (s->dirty_submodule)
2798                dirty = "-dirty";
2799
2800        strbuf_addf(&buf, "Subproject commit %s%s\n",
2801                    oid_to_hex(&s->oid), dirty);
2802        s->size = buf.len;
2803        if (size_only) {
2804                s->data = NULL;
2805                strbuf_release(&buf);
2806        } else {
2807                s->data = strbuf_detach(&buf, NULL);
2808                s->should_free = 1;
2809        }
2810        return 0;
2811}
2812
2813/*
2814 * While doing rename detection and pickaxe operation, we may need to
2815 * grab the data for the blob (or file) for our own in-core comparison.
2816 * diff_filespec has data and size fields for this purpose.
2817 */
2818int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2819{
2820        int size_only = flags & CHECK_SIZE_ONLY;
2821        int err = 0;
2822        /*
2823         * demote FAIL to WARN to allow inspecting the situation
2824         * instead of refusing.
2825         */
2826        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2827                                    ? SAFE_CRLF_WARN
2828                                    : safe_crlf);
2829
2830        if (!DIFF_FILE_VALID(s))
2831                die("internal error: asking to populate invalid file.");
2832        if (S_ISDIR(s->mode))
2833                return -1;
2834
2835        if (s->data)
2836                return 0;
2837
2838        if (size_only && 0 < s->size)
2839                return 0;
2840
2841        if (S_ISGITLINK(s->mode))
2842                return diff_populate_gitlink(s, size_only);
2843
2844        if (!s->oid_valid ||
2845            reuse_worktree_file(s->path, s->oid.hash, 0)) {
2846                struct strbuf buf = STRBUF_INIT;
2847                struct stat st;
2848                int fd;
2849
2850                if (lstat(s->path, &st) < 0) {
2851                        if (errno == ENOENT) {
2852                        err_empty:
2853                                err = -1;
2854                        empty:
2855                                s->data = (char *)"";
2856                                s->size = 0;
2857                                return err;
2858                        }
2859                }
2860                s->size = xsize_t(st.st_size);
2861                if (!s->size)
2862                        goto empty;
2863                if (S_ISLNK(st.st_mode)) {
2864                        struct strbuf sb = STRBUF_INIT;
2865
2866                        if (strbuf_readlink(&sb, s->path, s->size))
2867                                goto err_empty;
2868                        s->size = sb.len;
2869                        s->data = strbuf_detach(&sb, NULL);
2870                        s->should_free = 1;
2871                        return 0;
2872                }
2873
2874                /*
2875                 * Even if the caller would be happy with getting
2876                 * only the size, we cannot return early at this
2877                 * point if the path requires us to run the content
2878                 * conversion.
2879                 */
2880                if (size_only && !would_convert_to_git(s->path))
2881                        return 0;
2882
2883                /*
2884                 * Note: this check uses xsize_t(st.st_size) that may
2885                 * not be the true size of the blob after it goes
2886                 * through convert_to_git().  This may not strictly be
2887                 * correct, but the whole point of big_file_threshold
2888                 * and is_binary check being that we want to avoid
2889                 * opening the file and inspecting the contents, this
2890                 * is probably fine.
2891                 */
2892                if ((flags & CHECK_BINARY) &&
2893                    s->size > big_file_threshold && s->is_binary == -1) {
2894                        s->is_binary = 1;
2895                        return 0;
2896                }
2897                fd = open(s->path, O_RDONLY);
2898                if (fd < 0)
2899                        goto err_empty;
2900                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2901                close(fd);
2902                s->should_munmap = 1;
2903
2904                /*
2905                 * Convert from working tree format to canonical git format
2906                 */
2907                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2908                        size_t size = 0;
2909                        munmap(s->data, s->size);
2910                        s->should_munmap = 0;
2911                        s->data = strbuf_detach(&buf, &size);
2912                        s->size = size;
2913                        s->should_free = 1;
2914                }
2915        }
2916        else {
2917                enum object_type type;
2918                if (size_only || (flags & CHECK_BINARY)) {
2919                        type = sha1_object_info(s->oid.hash, &s->size);
2920                        if (type < 0)
2921                                die("unable to read %s",
2922                                    oid_to_hex(&s->oid));
2923                        if (size_only)
2924                                return 0;
2925                        if (s->size > big_file_threshold && s->is_binary == -1) {
2926                                s->is_binary = 1;
2927                                return 0;
2928                        }
2929                }
2930                s->data = read_sha1_file(s->oid.hash, &type, &s->size);
2931                if (!s->data)
2932                        die("unable to read %s", oid_to_hex(&s->oid));
2933                s->should_free = 1;
2934        }
2935        return 0;
2936}
2937
2938void diff_free_filespec_blob(struct diff_filespec *s)
2939{
2940        if (s->should_free)
2941                free(s->data);
2942        else if (s->should_munmap)
2943                munmap(s->data, s->size);
2944
2945        if (s->should_free || s->should_munmap) {
2946                s->should_free = s->should_munmap = 0;
2947                s->data = NULL;
2948        }
2949}
2950
2951void diff_free_filespec_data(struct diff_filespec *s)
2952{
2953        diff_free_filespec_blob(s);
2954        free(s->cnt_data);
2955        s->cnt_data = NULL;
2956}
2957
2958static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2959                           void *blob,
2960                           unsigned long size,
2961                           const struct object_id *oid,
2962                           int mode)
2963{
2964        int fd;
2965        struct strbuf buf = STRBUF_INIT;
2966        struct strbuf template = STRBUF_INIT;
2967        char *path_dup = xstrdup(path);
2968        const char *base = basename(path_dup);
2969
2970        /* Generate "XXXXXX_basename.ext" */
2971        strbuf_addstr(&template, "XXXXXX_");
2972        strbuf_addstr(&template, base);
2973
2974        fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
2975        if (fd < 0)
2976                die_errno("unable to create temp-file");
2977        if (convert_to_working_tree(path,
2978                        (const char *)blob, (size_t)size, &buf)) {
2979                blob = buf.buf;
2980                size = buf.len;
2981        }
2982        if (write_in_full(fd, blob, size) != size)
2983                die_errno("unable to write temp-file");
2984        close_tempfile(&temp->tempfile);
2985        temp->name = get_tempfile_path(&temp->tempfile);
2986        oid_to_hex_r(temp->hex, oid);
2987        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
2988        strbuf_release(&buf);
2989        strbuf_release(&template);
2990        free(path_dup);
2991}
2992
2993static struct diff_tempfile *prepare_temp_file(const char *name,
2994                struct diff_filespec *one)
2995{
2996        struct diff_tempfile *temp = claim_diff_tempfile();
2997
2998        if (!DIFF_FILE_VALID(one)) {
2999        not_a_valid_file:
3000                /* A '-' entry produces this for file-2, and
3001                 * a '+' entry produces this for file-1.
3002                 */
3003                temp->name = "/dev/null";
3004                xsnprintf(temp->hex, sizeof(temp->hex), ".");
3005                xsnprintf(temp->mode, sizeof(temp->mode), ".");
3006                return temp;
3007        }
3008
3009        if (!S_ISGITLINK(one->mode) &&
3010            (!one->oid_valid ||
3011             reuse_worktree_file(name, one->oid.hash, 1))) {
3012                struct stat st;
3013                if (lstat(name, &st) < 0) {
3014                        if (errno == ENOENT)
3015                                goto not_a_valid_file;
3016                        die_errno("stat(%s)", name);
3017                }
3018                if (S_ISLNK(st.st_mode)) {
3019                        struct strbuf sb = STRBUF_INIT;
3020                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
3021                                die_errno("readlink(%s)", name);
3022                        prep_temp_blob(name, temp, sb.buf, sb.len,
3023                                       (one->oid_valid ?
3024                                        &one->oid : &null_oid),
3025                                       (one->oid_valid ?
3026                                        one->mode : S_IFLNK));
3027                        strbuf_release(&sb);
3028                }
3029                else {
3030                        /* we can borrow from the file in the work tree */
3031                        temp->name = name;
3032                        if (!one->oid_valid)
3033                                sha1_to_hex_r(temp->hex, null_sha1);
3034                        else
3035                                oid_to_hex_r(temp->hex, &one->oid);
3036                        /* Even though we may sometimes borrow the
3037                         * contents from the work tree, we always want
3038                         * one->mode.  mode is trustworthy even when
3039                         * !(one->sha1_valid), as long as
3040                         * DIFF_FILE_VALID(one).
3041                         */
3042                        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3043                }
3044                return temp;
3045        }
3046        else {
3047                if (diff_populate_filespec(one, 0))
3048                        die("cannot read data blob for %s", one->path);
3049                prep_temp_blob(name, temp, one->data, one->size,
3050                               &one->oid, one->mode);
3051        }
3052        return temp;
3053}
3054
3055static void add_external_diff_name(struct argv_array *argv,
3056                                   const char *name,
3057                                   struct diff_filespec *df)
3058{
3059        struct diff_tempfile *temp = prepare_temp_file(name, df);
3060        argv_array_push(argv, temp->name);
3061        argv_array_push(argv, temp->hex);
3062        argv_array_push(argv, temp->mode);
3063}
3064
3065/* An external diff command takes:
3066 *
3067 * diff-cmd name infile1 infile1-sha1 infile1-mode \
3068 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3069 *
3070 */
3071static void run_external_diff(const char *pgm,
3072                              const char *name,
3073                              const char *other,
3074                              struct diff_filespec *one,
3075                              struct diff_filespec *two,
3076                              const char *xfrm_msg,
3077                              int complete_rewrite,
3078                              struct diff_options *o)
3079{
3080        struct argv_array argv = ARGV_ARRAY_INIT;
3081        struct argv_array env = ARGV_ARRAY_INIT;
3082        struct diff_queue_struct *q = &diff_queued_diff;
3083
3084        argv_array_push(&argv, pgm);
3085        argv_array_push(&argv, name);
3086
3087        if (one && two) {
3088                add_external_diff_name(&argv, name, one);
3089                if (!other)
3090                        add_external_diff_name(&argv, name, two);
3091                else {
3092                        add_external_diff_name(&argv, other, two);
3093                        argv_array_push(&argv, other);
3094                        argv_array_push(&argv, xfrm_msg);
3095                }
3096        }
3097
3098        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3099        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3100
3101        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3102                die(_("external diff died, stopping at %s"), name);
3103
3104        remove_tempfile();
3105        argv_array_clear(&argv);
3106        argv_array_clear(&env);
3107}
3108
3109static int similarity_index(struct diff_filepair *p)
3110{
3111        return p->score * 100 / MAX_SCORE;
3112}
3113
3114static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3115{
3116        if (startup_info->have_repository)
3117                return find_unique_abbrev(oid->hash, abbrev);
3118        else {
3119                char *hex = oid_to_hex(oid);
3120                if (abbrev < 0)
3121                        abbrev = FALLBACK_DEFAULT_ABBREV;
3122                if (abbrev > GIT_SHA1_HEXSZ)
3123                        die("BUG: oid abbreviation out of range: %d", abbrev);
3124                if (abbrev)
3125                        hex[abbrev] = '\0';
3126                return hex;
3127        }
3128}
3129
3130static void fill_metainfo(struct strbuf *msg,
3131                          const char *name,
3132                          const char *other,
3133                          struct diff_filespec *one,
3134                          struct diff_filespec *two,
3135                          struct diff_options *o,
3136                          struct diff_filepair *p,
3137                          int *must_show_header,
3138                          int use_color)
3139{
3140        const char *set = diff_get_color(use_color, DIFF_METAINFO);
3141        const char *reset = diff_get_color(use_color, DIFF_RESET);
3142        const char *line_prefix = diff_line_prefix(o);
3143
3144        *must_show_header = 1;
3145        strbuf_init(msg, PATH_MAX * 2 + 300);
3146        switch (p->status) {
3147        case DIFF_STATUS_COPIED:
3148                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3149                            line_prefix, set, similarity_index(p));
3150                strbuf_addf(msg, "%s\n%s%scopy from ",
3151                            reset,  line_prefix, set);
3152                quote_c_style(name, msg, NULL, 0);
3153                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3154                quote_c_style(other, msg, NULL, 0);
3155                strbuf_addf(msg, "%s\n", reset);
3156                break;
3157        case DIFF_STATUS_RENAMED:
3158                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3159                            line_prefix, set, similarity_index(p));
3160                strbuf_addf(msg, "%s\n%s%srename from ",
3161                            reset, line_prefix, set);
3162                quote_c_style(name, msg, NULL, 0);
3163                strbuf_addf(msg, "%s\n%s%srename to ",
3164                            reset, line_prefix, set);
3165                quote_c_style(other, msg, NULL, 0);
3166                strbuf_addf(msg, "%s\n", reset);
3167                break;
3168        case DIFF_STATUS_MODIFIED:
3169                if (p->score) {
3170                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3171                                    line_prefix,
3172                                    set, similarity_index(p), reset);
3173                        break;
3174                }
3175                /* fallthru */
3176        default:
3177                *must_show_header = 0;
3178        }
3179        if (one && two && oidcmp(&one->oid, &two->oid)) {
3180                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3181
3182                if (DIFF_OPT_TST(o, BINARY)) {
3183                        mmfile_t mf;
3184                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3185                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3186                                abbrev = 40;
3187                }
3188                strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3189                            diff_abbrev_oid(&one->oid, abbrev),
3190                            diff_abbrev_oid(&two->oid, abbrev));
3191                if (one->mode == two->mode)
3192                        strbuf_addf(msg, " %06o", one->mode);
3193                strbuf_addf(msg, "%s\n", reset);
3194        }
3195}
3196
3197static void run_diff_cmd(const char *pgm,
3198                         const char *name,
3199                         const char *other,
3200                         const char *attr_path,
3201                         struct diff_filespec *one,
3202                         struct diff_filespec *two,
3203                         struct strbuf *msg,
3204                         struct diff_options *o,
3205                         struct diff_filepair *p)
3206{
3207        const char *xfrm_msg = NULL;
3208        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3209        int must_show_header = 0;
3210
3211
3212        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3213                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3214                if (drv && drv->external)
3215                        pgm = drv->external;
3216        }
3217
3218        if (msg) {
3219                /*
3220                 * don't use colors when the header is intended for an
3221                 * external diff driver
3222                 */
3223                fill_metainfo(msg, name, other, one, two, o, p,
3224                              &must_show_header,
3225                              want_color(o->use_color) && !pgm);
3226                xfrm_msg = msg->len ? msg->buf : NULL;
3227        }
3228
3229        if (pgm) {
3230                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3231                                  complete_rewrite, o);
3232                return;
3233        }
3234        if (one && two)
3235                builtin_diff(name, other ? other : name,
3236                             one, two, xfrm_msg, must_show_header,
3237                             o, complete_rewrite);
3238        else
3239                fprintf(o->file, "* Unmerged path %s\n", name);
3240}
3241
3242static void diff_fill_sha1_info(struct diff_filespec *one)
3243{
3244        if (DIFF_FILE_VALID(one)) {
3245                if (!one->oid_valid) {
3246                        struct stat st;
3247                        if (one->is_stdin) {
3248                                oidclr(&one->oid);
3249                                return;
3250                        }
3251                        if (lstat(one->path, &st) < 0)
3252                                die_errno("stat '%s'", one->path);
3253                        if (index_path(one->oid.hash, one->path, &st, 0))
3254                                die("cannot hash %s", one->path);
3255                }
3256        }
3257        else
3258                oidclr(&one->oid);
3259}
3260
3261static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3262{
3263        /* Strip the prefix but do not molest /dev/null and absolute paths */
3264        if (*namep && **namep != '/') {
3265                *namep += prefix_length;
3266                if (**namep == '/')
3267                        ++*namep;
3268        }
3269        if (*otherp && **otherp != '/') {
3270                *otherp += prefix_length;
3271                if (**otherp == '/')
3272                        ++*otherp;
3273        }
3274}
3275
3276static void run_diff(struct diff_filepair *p, struct diff_options *o)
3277{
3278        const char *pgm = external_diff();
3279        struct strbuf msg;
3280        struct diff_filespec *one = p->one;
3281        struct diff_filespec *two = p->two;
3282        const char *name;
3283        const char *other;
3284        const char *attr_path;
3285
3286        name  = p->one->path;
3287        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3288        attr_path = name;
3289        if (o->prefix_length)
3290                strip_prefix(o->prefix_length, &name, &other);
3291
3292        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3293                pgm = NULL;
3294
3295        if (DIFF_PAIR_UNMERGED(p)) {
3296                run_diff_cmd(pgm, name, NULL, attr_path,
3297                             NULL, NULL, NULL, o, p);
3298                return;
3299        }
3300
3301        diff_fill_sha1_info(one);
3302        diff_fill_sha1_info(two);
3303
3304        if (!pgm &&
3305            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3306            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3307                /*
3308                 * a filepair that changes between file and symlink
3309                 * needs to be split into deletion and creation.
3310                 */
3311                struct diff_filespec *null = alloc_filespec(two->path);
3312                run_diff_cmd(NULL, name, other, attr_path,
3313                             one, null, &msg, o, p);
3314                free(null);
3315                strbuf_release(&msg);
3316
3317                null = alloc_filespec(one->path);
3318                run_diff_cmd(NULL, name, other, attr_path,
3319                             null, two, &msg, o, p);
3320                free(null);
3321        }
3322        else
3323                run_diff_cmd(pgm, name, other, attr_path,
3324                             one, two, &msg, o, p);
3325
3326        strbuf_release(&msg);
3327}
3328
3329static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3330                         struct diffstat_t *diffstat)
3331{
3332        const char *name;
3333        const char *other;
3334
3335        if (DIFF_PAIR_UNMERGED(p)) {
3336                /* unmerged */
3337                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3338                return;
3339        }
3340
3341        name = p->one->path;
3342        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3343
3344        if (o->prefix_length)
3345                strip_prefix(o->prefix_length, &name, &other);
3346
3347        diff_fill_sha1_info(p->one);
3348        diff_fill_sha1_info(p->two);
3349
3350        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3351}
3352
3353static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3354{
3355        const char *name;
3356        const char *other;
3357        const char *attr_path;
3358
3359        if (DIFF_PAIR_UNMERGED(p)) {
3360                /* unmerged */
3361                return;
3362        }
3363
3364        name = p->one->path;
3365        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3366        attr_path = other ? other : name;
3367
3368        if (o->prefix_length)
3369                strip_prefix(o->prefix_length, &name, &other);
3370
3371        diff_fill_sha1_info(p->one);
3372        diff_fill_sha1_info(p->two);
3373
3374        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3375}
3376
3377void diff_setup(struct diff_options *options)
3378{
3379        memcpy(options, &default_diff_options, sizeof(*options));
3380
3381        options->file = stdout;
3382
3383        options->abbrev = DEFAULT_ABBREV;
3384        options->line_termination = '\n';
3385        options->break_opt = -1;
3386        options->rename_limit = -1;
3387        options->dirstat_permille = diff_dirstat_permille_default;
3388        options->context = diff_context_default;
3389        options->interhunkcontext = diff_interhunk_context_default;
3390        options->ws_error_highlight = ws_error_highlight_default;
3391        DIFF_OPT_SET(options, RENAME_EMPTY);
3392
3393        /* pathchange left =NULL by default */
3394        options->change = diff_change;
3395        options->add_remove = diff_addremove;
3396        options->use_color = diff_use_color_default;
3397        options->detect_rename = diff_detect_rename_default;
3398        options->xdl_opts |= diff_algorithm;
3399        if (diff_indent_heuristic)
3400                DIFF_XDL_SET(options, INDENT_HEURISTIC);
3401
3402        options->orderfile = diff_order_file_cfg;
3403
3404        if (diff_no_prefix) {
3405                options->a_prefix = options->b_prefix = "";
3406        } else if (!diff_mnemonic_prefix) {
3407                options->a_prefix = "a/";
3408                options->b_prefix = "b/";
3409        }
3410}
3411
3412void diff_setup_done(struct diff_options *options)
3413{
3414        int count = 0;
3415
3416        if (options->set_default)
3417                options->set_default(options);
3418
3419        if (options->output_format & DIFF_FORMAT_NAME)
3420                count++;
3421        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3422                count++;
3423        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3424                count++;
3425        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3426                count++;
3427        if (count > 1)
3428                die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
3429
3430        /*
3431         * Most of the time we can say "there are changes"
3432         * only by checking if there are changed paths, but
3433         * --ignore-whitespace* options force us to look
3434         * inside contents.
3435         */
3436
3437        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3438            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3439            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3440                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3441        else
3442                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3443
3444        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3445                options->detect_rename = DIFF_DETECT_COPY;
3446
3447        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3448                options->prefix = NULL;
3449        if (options->prefix)
3450                options->prefix_length = strlen(options->prefix);
3451        else
3452                options->prefix_length = 0;
3453
3454        if (options->output_format & (DIFF_FORMAT_NAME |
3455                                      DIFF_FORMAT_NAME_STATUS |
3456                                      DIFF_FORMAT_CHECKDIFF |
3457                                      DIFF_FORMAT_NO_OUTPUT))
3458                options->output_format &= ~(DIFF_FORMAT_RAW |
3459                                            DIFF_FORMAT_NUMSTAT |
3460                                            DIFF_FORMAT_DIFFSTAT |
3461                                            DIFF_FORMAT_SHORTSTAT |
3462                                            DIFF_FORMAT_DIRSTAT |
3463                                            DIFF_FORMAT_SUMMARY |
3464                                            DIFF_FORMAT_PATCH);
3465
3466        /*
3467         * These cases always need recursive; we do not drop caller-supplied
3468         * recursive bits for other formats here.
3469         */
3470        if (options->output_format & (DIFF_FORMAT_PATCH |
3471                                      DIFF_FORMAT_NUMSTAT |
3472                                      DIFF_FORMAT_DIFFSTAT |
3473                                      DIFF_FORMAT_SHORTSTAT |
3474                                      DIFF_FORMAT_DIRSTAT |
3475                                      DIFF_FORMAT_SUMMARY |
3476                                      DIFF_FORMAT_CHECKDIFF))
3477                DIFF_OPT_SET(options, RECURSIVE);
3478        /*
3479         * Also pickaxe would not work very well if you do not say recursive
3480         */
3481        if (options->pickaxe)
3482                DIFF_OPT_SET(options, RECURSIVE);
3483        /*
3484         * When patches are generated, submodules diffed against the work tree
3485         * must be checked for dirtiness too so it can be shown in the output
3486         */
3487        if (options->output_format & DIFF_FORMAT_PATCH)
3488                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3489
3490        if (options->detect_rename && options->rename_limit < 0)
3491                options->rename_limit = diff_rename_limit_default;
3492        if (options->setup & DIFF_SETUP_USE_CACHE) {
3493                if (!active_cache)
3494                        /* read-cache does not die even when it fails
3495                         * so it is safe for us to do this here.  Also
3496                         * it does not smudge active_cache or active_nr
3497                         * when it fails, so we do not have to worry about
3498                         * cleaning it up ourselves either.
3499                         */
3500                        read_cache();
3501        }
3502        if (40 < options->abbrev)
3503                options->abbrev = 40; /* full */
3504
3505        /*
3506         * It does not make sense to show the first hit we happened
3507         * to have found.  It does not make sense not to return with
3508         * exit code in such a case either.
3509         */
3510        if (DIFF_OPT_TST(options, QUICK)) {
3511                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3512                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3513        }
3514
3515        options->diff_path_counter = 0;
3516
3517        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3518                die(_("--follow requires exactly one pathspec"));
3519}
3520
3521static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3522{
3523        char c, *eq;
3524        int len;
3525
3526        if (*arg != '-')
3527                return 0;
3528        c = *++arg;
3529        if (!c)
3530                return 0;
3531        if (c == arg_short) {
3532                c = *++arg;
3533                if (!c)
3534                        return 1;
3535                if (val && isdigit(c)) {
3536                        char *end;
3537                        int n = strtoul(arg, &end, 10);
3538                        if (*end)
3539                                return 0;
3540                        *val = n;
3541                        return 1;
3542                }
3543                return 0;
3544        }
3545        if (c != '-')
3546                return 0;
3547        arg++;
3548        eq = strchrnul(arg, '=');
3549        len = eq - arg;
3550        if (!len || strncmp(arg, arg_long, len))
3551                return 0;
3552        if (*eq) {
3553                int n;
3554                char *end;
3555                if (!isdigit(*++eq))
3556                        return 0;
3557                n = strtoul(eq, &end, 10);
3558                if (*end)
3559                        return 0;
3560                *val = n;
3561        }
3562        return 1;
3563}
3564
3565static int diff_scoreopt_parse(const char *opt);
3566
3567static inline int short_opt(char opt, const char **argv,
3568                            const char **optarg)
3569{
3570        const char *arg = argv[0];
3571        if (arg[0] != '-' || arg[1] != opt)
3572                return 0;
3573        if (arg[2] != '\0') {
3574                *optarg = arg + 2;
3575                return 1;
3576        }
3577        if (!argv[1])
3578                die("Option '%c' requires a value", opt);
3579        *optarg = argv[1];
3580        return 2;
3581}
3582
3583int parse_long_opt(const char *opt, const char **argv,
3584                   const char **optarg)
3585{
3586        const char *arg = argv[0];
3587        if (!skip_prefix(arg, "--", &arg))
3588                return 0;
3589        if (!skip_prefix(arg, opt, &arg))
3590                return 0;
3591        if (*arg == '=') { /* stuck form: --option=value */
3592                *optarg = arg + 1;
3593                return 1;
3594        }
3595        if (*arg != '\0')
3596                return 0;
3597        /* separate form: --option value */
3598        if (!argv[1])
3599                die("Option '--%s' requires a value", opt);
3600        *optarg = argv[1];
3601        return 2;
3602}
3603
3604static int stat_opt(struct diff_options *options, const char **av)
3605{
3606        const char *arg = av[0];
3607        char *end;
3608        int width = options->stat_width;
3609        int name_width = options->stat_name_width;
3610        int graph_width = options->stat_graph_width;
3611        int count = options->stat_count;
3612        int argcount = 1;
3613
3614        if (!skip_prefix(arg, "--stat", &arg))
3615                die("BUG: stat option does not begin with --stat: %s", arg);
3616        end = (char *)arg;
3617
3618        switch (*arg) {
3619        case '-':
3620                if (skip_prefix(arg, "-width", &arg)) {
3621                        if (*arg == '=')
3622                                width = strtoul(arg + 1, &end, 10);
3623                        else if (!*arg && !av[1])
3624                                die_want_option("--stat-width");
3625                        else if (!*arg) {
3626                                width = strtoul(av[1], &end, 10);
3627                                argcount = 2;
3628                        }
3629                } else if (skip_prefix(arg, "-name-width", &arg)) {
3630                        if (*arg == '=')
3631                                name_width = strtoul(arg + 1, &end, 10);
3632                        else if (!*arg && !av[1])
3633                                die_want_option("--stat-name-width");
3634                        else if (!*arg) {
3635                                name_width = strtoul(av[1], &end, 10);
3636                                argcount = 2;
3637                        }
3638                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3639                        if (*arg == '=')
3640                                graph_width = strtoul(arg + 1, &end, 10);
3641                        else if (!*arg && !av[1])
3642                                die_want_option("--stat-graph-width");
3643                        else if (!*arg) {
3644                                graph_width = strtoul(av[1], &end, 10);
3645                                argcount = 2;
3646                        }
3647                } else if (skip_prefix(arg, "-count", &arg)) {
3648                        if (*arg == '=')
3649                                count = strtoul(arg + 1, &end, 10);
3650                        else if (!*arg && !av[1])
3651                                die_want_option("--stat-count");
3652                        else if (!*arg) {
3653                                count = strtoul(av[1], &end, 10);
3654                                argcount = 2;
3655                        }
3656                }
3657                break;
3658        case '=':
3659                width = strtoul(arg+1, &end, 10);
3660                if (*end == ',')
3661                        name_width = strtoul(end+1, &end, 10);
3662                if (*end == ',')
3663                        count = strtoul(end+1, &end, 10);
3664        }
3665
3666        /* Important! This checks all the error cases! */
3667        if (*end)
3668                return 0;
3669        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3670        options->stat_name_width = name_width;
3671        options->stat_graph_width = graph_width;
3672        options->stat_width = width;
3673        options->stat_count = count;
3674        return argcount;
3675}
3676
3677static int parse_dirstat_opt(struct diff_options *options, const char *params)
3678{
3679        struct strbuf errmsg = STRBUF_INIT;
3680        if (parse_dirstat_params(options, params, &errmsg))
3681                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3682                    errmsg.buf);
3683        strbuf_release(&errmsg);
3684        /*
3685         * The caller knows a dirstat-related option is given from the command
3686         * line; allow it to say "return this_function();"
3687         */
3688        options->output_format |= DIFF_FORMAT_DIRSTAT;
3689        return 1;
3690}
3691
3692static int parse_submodule_opt(struct diff_options *options, const char *value)
3693{
3694        if (parse_submodule_params(options, value))
3695                die(_("Failed to parse --submodule option parameter: '%s'"),
3696                        value);
3697        return 1;
3698}
3699
3700static const char diff_status_letters[] = {
3701        DIFF_STATUS_ADDED,
3702        DIFF_STATUS_COPIED,
3703        DIFF_STATUS_DELETED,
3704        DIFF_STATUS_MODIFIED,
3705        DIFF_STATUS_RENAMED,
3706        DIFF_STATUS_TYPE_CHANGED,
3707        DIFF_STATUS_UNKNOWN,
3708        DIFF_STATUS_UNMERGED,
3709        DIFF_STATUS_FILTER_AON,
3710        DIFF_STATUS_FILTER_BROKEN,
3711        '\0',
3712};
3713
3714static unsigned int filter_bit['Z' + 1];
3715
3716static void prepare_filter_bits(void)
3717{
3718        int i;
3719
3720        if (!filter_bit[DIFF_STATUS_ADDED]) {
3721                for (i = 0; diff_status_letters[i]; i++)
3722                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3723        }
3724}
3725
3726static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3727{
3728        return opt->filter & filter_bit[(int) status];
3729}
3730
3731static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3732{
3733        int i, optch;
3734
3735        prepare_filter_bits();
3736
3737        /*
3738         * If there is a negation e.g. 'd' in the input, and we haven't
3739         * initialized the filter field with another --diff-filter, start
3740         * from full set of bits, except for AON.
3741         */
3742        if (!opt->filter) {
3743                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3744                        if (optch < 'a' || 'z' < optch)
3745                                continue;
3746                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3747                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3748                        break;
3749                }
3750        }
3751
3752        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3753                unsigned int bit;
3754                int negate;
3755
3756                if ('a' <= optch && optch <= 'z') {
3757                        negate = 1;
3758                        optch = toupper(optch);
3759                } else {
3760                        negate = 0;
3761                }
3762
3763                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3764                if (!bit)
3765                        return optarg[i];
3766                if (negate)
3767                        opt->filter &= ~bit;
3768                else
3769                        opt->filter |= bit;
3770        }
3771        return 0;
3772}
3773
3774static void enable_patch_output(int *fmt) {
3775        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3776        *fmt |= DIFF_FORMAT_PATCH;
3777}
3778
3779static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
3780{
3781        int val = parse_ws_error_highlight(arg);
3782
3783        if (val < 0) {
3784                error("unknown value after ws-error-highlight=%.*s",
3785                      -1 - val, arg);
3786                return 0;
3787        }
3788        opt->ws_error_highlight = val;
3789        return 1;
3790}
3791
3792int diff_opt_parse(struct diff_options *options,
3793                   const char **av, int ac, const char *prefix)
3794{
3795        const char *arg = av[0];
3796        const char *optarg;
3797        int argcount;
3798
3799        if (!prefix)
3800                prefix = "";
3801
3802        /* Output format options */
3803        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3804            || opt_arg(arg, 'U', "unified", &options->context))
3805                enable_patch_output(&options->output_format);
3806        else if (!strcmp(arg, "--raw"))
3807                options->output_format |= DIFF_FORMAT_RAW;
3808        else if (!strcmp(arg, "--patch-with-raw")) {
3809                enable_patch_output(&options->output_format);
3810                options->output_format |= DIFF_FORMAT_RAW;
3811        } else if (!strcmp(arg, "--numstat"))
3812                options->output_format |= DIFF_FORMAT_NUMSTAT;
3813        else if (!strcmp(arg, "--shortstat"))
3814                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3815        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3816                return parse_dirstat_opt(options, "");
3817        else if (skip_prefix(arg, "-X", &arg))
3818                return parse_dirstat_opt(options, arg);
3819        else if (skip_prefix(arg, "--dirstat=", &arg))
3820                return parse_dirstat_opt(options, arg);
3821        else if (!strcmp(arg, "--cumulative"))
3822                return parse_dirstat_opt(options, "cumulative");
3823        else if (!strcmp(arg, "--dirstat-by-file"))
3824                return parse_dirstat_opt(options, "files");
3825        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3826                parse_dirstat_opt(options, "files");
3827                return parse_dirstat_opt(options, arg);
3828        }
3829        else if (!strcmp(arg, "--check"))
3830                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3831        else if (!strcmp(arg, "--summary"))
3832                options->output_format |= DIFF_FORMAT_SUMMARY;
3833        else if (!strcmp(arg, "--patch-with-stat")) {
3834                enable_patch_output(&options->output_format);
3835                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3836        } else if (!strcmp(arg, "--name-only"))
3837                options->output_format |= DIFF_FORMAT_NAME;
3838        else if (!strcmp(arg, "--name-status"))
3839                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3840        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3841                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3842        else if (starts_with(arg, "--stat"))
3843                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3844                return stat_opt(options, av);
3845
3846        /* renames options */
3847        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3848                 !strcmp(arg, "--break-rewrites")) {
3849                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3850                        return error("invalid argument to -B: %s", arg+2);
3851        }
3852        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3853                 !strcmp(arg, "--find-renames")) {
3854                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3855                        return error("invalid argument to -M: %s", arg+2);
3856                options->detect_rename = DIFF_DETECT_RENAME;
3857        }
3858        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3859                options->irreversible_delete = 1;
3860        }
3861        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3862                 !strcmp(arg, "--find-copies")) {
3863                if (options->detect_rename == DIFF_DETECT_COPY)
3864                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3865                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3866                        return error("invalid argument to -C: %s", arg+2);
3867                options->detect_rename = DIFF_DETECT_COPY;
3868        }
3869        else if (!strcmp(arg, "--no-renames"))
3870                options->detect_rename = 0;
3871        else if (!strcmp(arg, "--rename-empty"))
3872                DIFF_OPT_SET(options, RENAME_EMPTY);
3873        else if (!strcmp(arg, "--no-rename-empty"))
3874                DIFF_OPT_CLR(options, RENAME_EMPTY);
3875        else if (!strcmp(arg, "--relative"))
3876                DIFF_OPT_SET(options, RELATIVE_NAME);
3877        else if (skip_prefix(arg, "--relative=", &arg)) {
3878                DIFF_OPT_SET(options, RELATIVE_NAME);
3879                options->prefix = arg;
3880        }
3881
3882        /* xdiff options */
3883        else if (!strcmp(arg, "--minimal"))
3884                DIFF_XDL_SET(options, NEED_MINIMAL);
3885        else if (!strcmp(arg, "--no-minimal"))
3886                DIFF_XDL_CLR(options, NEED_MINIMAL);
3887        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3888                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3889        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3890                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3891        else if (!strcmp(arg, "--ignore-space-at-eol"))
3892                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3893        else if (!strcmp(arg, "--ignore-blank-lines"))
3894                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3895        else if (!strcmp(arg, "--indent-heuristic"))
3896                DIFF_XDL_SET(options, INDENT_HEURISTIC);
3897        else if (!strcmp(arg, "--no-indent-heuristic"))
3898                DIFF_XDL_CLR(options, INDENT_HEURISTIC);
3899        else if (!strcmp(arg, "--patience"))
3900                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3901        else if (!strcmp(arg, "--histogram"))
3902                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3903        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3904                long value = parse_algorithm_value(optarg);
3905                if (value < 0)
3906                        return error("option diff-algorithm accepts \"myers\", "
3907                                     "\"minimal\", \"patience\" and \"histogram\"");
3908                /* clear out previous settings */
3909                DIFF_XDL_CLR(options, NEED_MINIMAL);
3910                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3911                options->xdl_opts |= value;
3912                return argcount;
3913        }
3914
3915        /* flags options */
3916        else if (!strcmp(arg, "--binary")) {
3917                enable_patch_output(&options->output_format);
3918                DIFF_OPT_SET(options, BINARY);
3919        }
3920        else if (!strcmp(arg, "--full-index"))
3921                DIFF_OPT_SET(options, FULL_INDEX);
3922        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3923                DIFF_OPT_SET(options, TEXT);
3924        else if (!strcmp(arg, "-R"))
3925                DIFF_OPT_SET(options, REVERSE_DIFF);
3926        else if (!strcmp(arg, "--find-copies-harder"))
3927                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3928        else if (!strcmp(arg, "--follow"))
3929                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3930        else if (!strcmp(arg, "--no-follow")) {
3931                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3932                DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
3933        } else if (!strcmp(arg, "--color"))
3934                options->use_color = 1;
3935        else if (skip_prefix(arg, "--color=", &arg)) {
3936                int value = git_config_colorbool(NULL, arg);
3937                if (value < 0)
3938                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3939                options->use_color = value;
3940        }
3941        else if (!strcmp(arg, "--no-color"))
3942                options->use_color = 0;
3943        else if (!strcmp(arg, "--color-words")) {
3944                options->use_color = 1;
3945                options->word_diff = DIFF_WORDS_COLOR;
3946        }
3947        else if (skip_prefix(arg, "--color-words=", &arg)) {
3948                options->use_color = 1;
3949                options->word_diff = DIFF_WORDS_COLOR;
3950                options->word_regex = arg;
3951        }
3952        else if (!strcmp(arg, "--word-diff")) {
3953                if (options->word_diff == DIFF_WORDS_NONE)
3954                        options->word_diff = DIFF_WORDS_PLAIN;
3955        }
3956        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3957                if (!strcmp(arg, "plain"))
3958                        options->word_diff = DIFF_WORDS_PLAIN;
3959                else if (!strcmp(arg, "color")) {
3960                        options->use_color = 1;
3961                        options->word_diff = DIFF_WORDS_COLOR;
3962                }
3963                else if (!strcmp(arg, "porcelain"))
3964                        options->word_diff = DIFF_WORDS_PORCELAIN;
3965                else if (!strcmp(arg, "none"))
3966                        options->word_diff = DIFF_WORDS_NONE;
3967                else
3968                        die("bad --word-diff argument: %s", arg);
3969        }
3970        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3971                if (options->word_diff == DIFF_WORDS_NONE)
3972                        options->word_diff = DIFF_WORDS_PLAIN;
3973                options->word_regex = optarg;
3974                return argcount;
3975        }
3976        else if (!strcmp(arg, "--exit-code"))
3977                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3978        else if (!strcmp(arg, "--quiet"))
3979                DIFF_OPT_SET(options, QUICK);
3980        else if (!strcmp(arg, "--ext-diff"))
3981                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3982        else if (!strcmp(arg, "--no-ext-diff"))
3983                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3984        else if (!strcmp(arg, "--textconv"))
3985                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3986        else if (!strcmp(arg, "--no-textconv"))
3987                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3988        else if (!strcmp(arg, "--ignore-submodules")) {
3989                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3990                handle_ignore_submodules_arg(options, "all");
3991        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3992                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3993                handle_ignore_submodules_arg(options, arg);
3994        } else if (!strcmp(arg, "--submodule"))
3995                options->submodule_format = DIFF_SUBMODULE_LOG;
3996        else if (skip_prefix(arg, "--submodule=", &arg))
3997                return parse_submodule_opt(options, arg);
3998        else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
3999                return parse_ws_error_highlight_opt(options, arg);
4000        else if (!strcmp(arg, "--ita-invisible-in-index"))
4001                options->ita_invisible_in_index = 1;
4002        else if (!strcmp(arg, "--ita-visible-in-index"))
4003                options->ita_invisible_in_index = 0;
4004
4005        /* misc options */
4006        else if (!strcmp(arg, "-z"))
4007                options->line_termination = 0;
4008        else if ((argcount = short_opt('l', av, &optarg))) {
4009                options->rename_limit = strtoul(optarg, NULL, 10);
4010                return argcount;
4011        }
4012        else if ((argcount = short_opt('S', av, &optarg))) {
4013                options->pickaxe = optarg;
4014                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4015                return argcount;
4016        } else if ((argcount = short_opt('G', av, &optarg))) {
4017                options->pickaxe = optarg;
4018                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4019                return argcount;
4020        }
4021        else if (!strcmp(arg, "--pickaxe-all"))
4022                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4023        else if (!strcmp(arg, "--pickaxe-regex"))
4024                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4025        else if ((argcount = short_opt('O', av, &optarg))) {
4026                options->orderfile = prefix_filename(prefix, optarg);
4027                return argcount;
4028        }
4029        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4030                int offending = parse_diff_filter_opt(optarg, options);
4031                if (offending)
4032                        die("unknown change class '%c' in --diff-filter=%s",
4033                            offending, optarg);
4034                return argcount;
4035        }
4036        else if (!strcmp(arg, "--no-abbrev"))
4037                options->abbrev = 0;
4038        else if (!strcmp(arg, "--abbrev"))
4039                options->abbrev = DEFAULT_ABBREV;
4040        else if (skip_prefix(arg, "--abbrev=", &arg)) {
4041                options->abbrev = strtoul(arg, NULL, 10);
4042                if (options->abbrev < MINIMUM_ABBREV)
4043                        options->abbrev = MINIMUM_ABBREV;
4044                else if (40 < options->abbrev)
4045                        options->abbrev = 40;
4046        }
4047        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4048                options->a_prefix = optarg;
4049                return argcount;
4050        }
4051        else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4052                options->line_prefix = optarg;
4053                options->line_prefix_length = strlen(options->line_prefix);
4054                graph_setup_line_prefix(options);
4055                return argcount;
4056        }
4057        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4058                options->b_prefix = optarg;
4059                return argcount;
4060        }
4061        else if (!strcmp(arg, "--no-prefix"))
4062                options->a_prefix = options->b_prefix = "";
4063        else if (opt_arg(arg, '\0', "inter-hunk-context",
4064                         &options->interhunkcontext))
4065                ;
4066        else if (!strcmp(arg, "-W"))
4067                DIFF_OPT_SET(options, FUNCCONTEXT);
4068        else if (!strcmp(arg, "--function-context"))
4069                DIFF_OPT_SET(options, FUNCCONTEXT);
4070        else if (!strcmp(arg, "--no-function-context"))
4071                DIFF_OPT_CLR(options, FUNCCONTEXT);
4072        else if ((argcount = parse_long_opt("output", av, &optarg))) {
4073                char *path = prefix_filename(prefix, optarg);
4074                options->file = fopen(path, "w");
4075                if (!options->file)
4076                        die_errno("Could not open '%s'", path);
4077                options->close_file = 1;
4078                if (options->use_color != GIT_COLOR_ALWAYS)
4079                        options->use_color = GIT_COLOR_NEVER;
4080                free(path);
4081                return argcount;
4082        } else
4083                return 0;
4084        return 1;
4085}
4086
4087int parse_rename_score(const char **cp_p)
4088{
4089        unsigned long num, scale;
4090        int ch, dot;
4091        const char *cp = *cp_p;
4092
4093        num = 0;
4094        scale = 1;
4095        dot = 0;
4096        for (;;) {
4097                ch = *cp;
4098                if ( !dot && ch == '.' ) {
4099                        scale = 1;
4100                        dot = 1;
4101                } else if ( ch == '%' ) {
4102                        scale = dot ? scale*100 : 100;
4103                        cp++;   /* % is always at the end */
4104                        break;
4105                } else if ( ch >= '0' && ch <= '9' ) {
4106                        if ( scale < 100000 ) {
4107                                scale *= 10;
4108                                num = (num*10) + (ch-'0');
4109                        }
4110                } else {
4111                        break;
4112                }
4113                cp++;
4114        }
4115        *cp_p = cp;
4116
4117        /* user says num divided by scale and we say internally that
4118         * is MAX_SCORE * num / scale.
4119         */
4120        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4121}
4122
4123static int diff_scoreopt_parse(const char *opt)
4124{
4125        int opt1, opt2, cmd;
4126
4127        if (*opt++ != '-')
4128                return -1;
4129        cmd = *opt++;
4130        if (cmd == '-') {
4131                /* convert the long-form arguments into short-form versions */
4132                if (skip_prefix(opt, "break-rewrites", &opt)) {
4133                        if (*opt == 0 || *opt++ == '=')
4134                                cmd = 'B';
4135                } else if (skip_prefix(opt, "find-copies", &opt)) {
4136                        if (*opt == 0 || *opt++ == '=')
4137                                cmd = 'C';
4138                } else if (skip_prefix(opt, "find-renames", &opt)) {
4139                        if (*opt == 0 || *opt++ == '=')
4140                                cmd = 'M';
4141                }
4142        }
4143        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4144                return -1; /* that is not a -M, -C, or -B option */
4145
4146        opt1 = parse_rename_score(&opt);
4147        if (cmd != 'B')
4148                opt2 = 0;
4149        else {
4150                if (*opt == 0)
4151                        opt2 = 0;
4152                else if (*opt != '/')
4153                        return -1; /* we expect -B80/99 or -B80 */
4154                else {
4155                        opt++;
4156                        opt2 = parse_rename_score(&opt);
4157                }
4158        }
4159        if (*opt != 0)
4160                return -1;
4161        return opt1 | (opt2 << 16);
4162}
4163
4164struct diff_queue_struct diff_queued_diff;
4165
4166void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4167{
4168        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4169        queue->queue[queue->nr++] = dp;
4170}
4171
4172struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4173                                 struct diff_filespec *one,
4174                                 struct diff_filespec *two)
4175{
4176        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4177        dp->one = one;
4178        dp->two = two;
4179        if (queue)
4180                diff_q(queue, dp);
4181        return dp;
4182}
4183
4184void diff_free_filepair(struct diff_filepair *p)
4185{
4186        free_filespec(p->one);
4187        free_filespec(p->two);
4188        free(p);
4189}
4190
4191const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4192{
4193        int abblen;
4194        const char *abbrev;
4195
4196        if (len == GIT_SHA1_HEXSZ)
4197                return oid_to_hex(oid);
4198
4199        abbrev = diff_abbrev_oid(oid, len);
4200        abblen = strlen(abbrev);
4201
4202        /*
4203         * In well-behaved cases, where the abbbreviated result is the
4204         * same as the requested length, append three dots after the
4205         * abbreviation (hence the whole logic is limited to the case
4206         * where abblen < 37); when the actual abbreviated result is a
4207         * bit longer than the requested length, we reduce the number
4208         * of dots so that they match the well-behaved ones.  However,
4209         * if the actual abbreviation is longer than the requested
4210         * length by more than three, we give up on aligning, and add
4211         * three dots anyway, to indicate that the output is not the
4212         * full object name.  Yes, this may be suboptimal, but this
4213         * appears only in "diff --raw --abbrev" output and it is not
4214         * worth the effort to change it now.  Note that this would
4215         * likely to work fine when the automatic sizing of default
4216         * abbreviation length is used--we would be fed -1 in "len" in
4217         * that case, and will end up always appending three-dots, but
4218         * the automatic sizing is supposed to give abblen that ensures
4219         * uniqueness across all objects (statistically speaking).
4220         */
4221        if (abblen < GIT_SHA1_HEXSZ - 3) {
4222                static char hex[GIT_MAX_HEXSZ + 1];
4223                if (len < abblen && abblen <= len + 2)
4224                        xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4225                else
4226                        xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4227                return hex;
4228        }
4229
4230        return oid_to_hex(oid);
4231}
4232
4233static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4234{
4235        int line_termination = opt->line_termination;
4236        int inter_name_termination = line_termination ? '\t' : '\0';
4237
4238        fprintf(opt->file, "%s", diff_line_prefix(opt));
4239        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4240                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4241                        diff_aligned_abbrev(&p->one->oid, opt->abbrev));
4242                fprintf(opt->file, "%s ",
4243                        diff_aligned_abbrev(&p->two->oid, opt->abbrev));
4244        }
4245        if (p->score) {
4246                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4247                        inter_name_termination);
4248        } else {
4249                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4250        }
4251
4252        if (p->status == DIFF_STATUS_COPIED ||
4253            p->status == DIFF_STATUS_RENAMED) {
4254                const char *name_a, *name_b;
4255                name_a = p->one->path;
4256                name_b = p->two->path;
4257                strip_prefix(opt->prefix_length, &name_a, &name_b);
4258                write_name_quoted(name_a, opt->file, inter_name_termination);
4259                write_name_quoted(name_b, opt->file, line_termination);
4260        } else {
4261                const char *name_a, *name_b;
4262                name_a = p->one->mode ? p->one->path : p->two->path;
4263                name_b = NULL;
4264                strip_prefix(opt->prefix_length, &name_a, &name_b);
4265                write_name_quoted(name_a, opt->file, line_termination);
4266        }
4267}
4268
4269int diff_unmodified_pair(struct diff_filepair *p)
4270{
4271        /* This function is written stricter than necessary to support
4272         * the currently implemented transformers, but the idea is to
4273         * let transformers to produce diff_filepairs any way they want,
4274         * and filter and clean them up here before producing the output.
4275         */
4276        struct diff_filespec *one = p->one, *two = p->two;
4277
4278        if (DIFF_PAIR_UNMERGED(p))
4279                return 0; /* unmerged is interesting */
4280
4281        /* deletion, addition, mode or type change
4282         * and rename are all interesting.
4283         */
4284        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4285            DIFF_PAIR_MODE_CHANGED(p) ||
4286            strcmp(one->path, two->path))
4287                return 0;
4288
4289        /* both are valid and point at the same path.  that is, we are
4290         * dealing with a change.
4291         */
4292        if (one->oid_valid && two->oid_valid &&
4293            !oidcmp(&one->oid, &two->oid) &&
4294            !one->dirty_submodule && !two->dirty_submodule)
4295                return 1; /* no change */
4296        if (!one->oid_valid && !two->oid_valid)
4297                return 1; /* both look at the same file on the filesystem. */
4298        return 0;
4299}
4300
4301static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4302{
4303        if (diff_unmodified_pair(p))
4304                return;
4305
4306        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4307            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4308                return; /* no tree diffs in patch format */
4309
4310        run_diff(p, o);
4311}
4312
4313static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4314                            struct diffstat_t *diffstat)
4315{
4316        if (diff_unmodified_pair(p))
4317                return;
4318
4319        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4320            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4321                return; /* no useful stat for tree diffs */
4322
4323        run_diffstat(p, o, diffstat);
4324}
4325
4326static void diff_flush_checkdiff(struct diff_filepair *p,
4327                struct diff_options *o)
4328{
4329        if (diff_unmodified_pair(p))
4330                return;
4331
4332        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4333            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4334                return; /* nothing to check in tree diffs */
4335
4336        run_checkdiff(p, o);
4337}
4338
4339int diff_queue_is_empty(void)
4340{
4341        struct diff_queue_struct *q = &diff_queued_diff;
4342        int i;
4343        for (i = 0; i < q->nr; i++)
4344                if (!diff_unmodified_pair(q->queue[i]))
4345                        return 0;
4346        return 1;
4347}
4348
4349#if DIFF_DEBUG
4350void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4351{
4352        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4353                x, one ? one : "",
4354                s->path,
4355                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4356                s->mode,
4357                s->oid_valid ? oid_to_hex(&s->oid) : "");
4358        fprintf(stderr, "queue[%d] %s size %lu\n",
4359                x, one ? one : "",
4360                s->size);
4361}
4362
4363void diff_debug_filepair(const struct diff_filepair *p, int i)
4364{
4365        diff_debug_filespec(p->one, i, "one");
4366        diff_debug_filespec(p->two, i, "two");
4367        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4368                p->score, p->status ? p->status : '?',
4369                p->one->rename_used, p->broken_pair);
4370}
4371
4372void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4373{
4374        int i;
4375        if (msg)
4376                fprintf(stderr, "%s\n", msg);
4377        fprintf(stderr, "q->nr = %d\n", q->nr);
4378        for (i = 0; i < q->nr; i++) {
4379                struct diff_filepair *p = q->queue[i];
4380                diff_debug_filepair(p, i);
4381        }
4382}
4383#endif
4384
4385static void diff_resolve_rename_copy(void)
4386{
4387        int i;
4388        struct diff_filepair *p;
4389        struct diff_queue_struct *q = &diff_queued_diff;
4390
4391        diff_debug_queue("resolve-rename-copy", q);
4392
4393        for (i = 0; i < q->nr; i++) {
4394                p = q->queue[i];
4395                p->status = 0; /* undecided */
4396                if (DIFF_PAIR_UNMERGED(p))
4397                        p->status = DIFF_STATUS_UNMERGED;
4398                else if (!DIFF_FILE_VALID(p->one))
4399                        p->status = DIFF_STATUS_ADDED;
4400                else if (!DIFF_FILE_VALID(p->two))
4401                        p->status = DIFF_STATUS_DELETED;
4402                else if (DIFF_PAIR_TYPE_CHANGED(p))
4403                        p->status = DIFF_STATUS_TYPE_CHANGED;
4404
4405                /* from this point on, we are dealing with a pair
4406                 * whose both sides are valid and of the same type, i.e.
4407                 * either in-place edit or rename/copy edit.
4408                 */
4409                else if (DIFF_PAIR_RENAME(p)) {
4410                        /*
4411                         * A rename might have re-connected a broken
4412                         * pair up, causing the pathnames to be the
4413                         * same again. If so, that's not a rename at
4414                         * all, just a modification..
4415                         *
4416                         * Otherwise, see if this source was used for
4417                         * multiple renames, in which case we decrement
4418                         * the count, and call it a copy.
4419                         */
4420                        if (!strcmp(p->one->path, p->two->path))
4421                                p->status = DIFF_STATUS_MODIFIED;
4422                        else if (--p->one->rename_used > 0)
4423                                p->status = DIFF_STATUS_COPIED;
4424                        else
4425                                p->status = DIFF_STATUS_RENAMED;
4426                }
4427                else if (oidcmp(&p->one->oid, &p->two->oid) ||
4428                         p->one->mode != p->two->mode ||
4429                         p->one->dirty_submodule ||
4430                         p->two->dirty_submodule ||
4431                         is_null_oid(&p->one->oid))
4432                        p->status = DIFF_STATUS_MODIFIED;
4433                else {
4434                        /* This is a "no-change" entry and should not
4435                         * happen anymore, but prepare for broken callers.
4436                         */
4437                        error("feeding unmodified %s to diffcore",
4438                              p->one->path);
4439                        p->status = DIFF_STATUS_UNKNOWN;
4440                }
4441        }
4442        diff_debug_queue("resolve-rename-copy done", q);
4443}
4444
4445static int check_pair_status(struct diff_filepair *p)
4446{
4447        switch (p->status) {
4448        case DIFF_STATUS_UNKNOWN:
4449                return 0;
4450        case 0:
4451                die("internal error in diff-resolve-rename-copy");
4452        default:
4453                return 1;
4454        }
4455}
4456
4457static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4458{
4459        int fmt = opt->output_format;
4460
4461        if (fmt & DIFF_FORMAT_CHECKDIFF)
4462                diff_flush_checkdiff(p, opt);
4463        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4464                diff_flush_raw(p, opt);
4465        else if (fmt & DIFF_FORMAT_NAME) {
4466                const char *name_a, *name_b;
4467                name_a = p->two->path;
4468                name_b = NULL;
4469                strip_prefix(opt->prefix_length, &name_a, &name_b);
4470                fprintf(opt->file, "%s", diff_line_prefix(opt));
4471                write_name_quoted(name_a, opt->file, opt->line_termination);
4472        }
4473}
4474
4475static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4476{
4477        if (fs->mode)
4478                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4479        else
4480                fprintf(file, " %s ", newdelete);
4481        write_name_quoted(fs->path, file, '\n');
4482}
4483
4484
4485static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4486                const char *line_prefix)
4487{
4488        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4489                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4490                        p->two->mode, show_name ? ' ' : '\n');
4491                if (show_name) {
4492                        write_name_quoted(p->two->path, file, '\n');
4493                }
4494        }
4495}
4496
4497static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4498                        const char *line_prefix)
4499{
4500        char *names = pprint_rename(p->one->path, p->two->path);
4501
4502        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4503        free(names);
4504        show_mode_change(file, p, 0, line_prefix);
4505}
4506
4507static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4508{
4509        FILE *file = opt->file;
4510        const char *line_prefix = diff_line_prefix(opt);
4511
4512        switch(p->status) {
4513        case DIFF_STATUS_DELETED:
4514                fputs(line_prefix, file);
4515                show_file_mode_name(file, "delete", p->one);
4516                break;
4517        case DIFF_STATUS_ADDED:
4518                fputs(line_prefix, file);
4519                show_file_mode_name(file, "create", p->two);
4520                break;
4521        case DIFF_STATUS_COPIED:
4522                fputs(line_prefix, file);
4523                show_rename_copy(file, "copy", p, line_prefix);
4524                break;
4525        case DIFF_STATUS_RENAMED:
4526                fputs(line_prefix, file);
4527                show_rename_copy(file, "rename", p, line_prefix);
4528                break;
4529        default:
4530                if (p->score) {
4531                        fprintf(file, "%s rewrite ", line_prefix);
4532                        write_name_quoted(p->two->path, file, ' ');
4533                        fprintf(file, "(%d%%)\n", similarity_index(p));
4534                }
4535                show_mode_change(file, p, !p->score, line_prefix);
4536                break;
4537        }
4538}
4539
4540struct patch_id_t {
4541        git_SHA_CTX *ctx;
4542        int patchlen;
4543};
4544
4545static int remove_space(char *line, int len)
4546{
4547        int i;
4548        char *dst = line;
4549        unsigned char c;
4550
4551        for (i = 0; i < len; i++)
4552                if (!isspace((c = line[i])))
4553                        *dst++ = c;
4554
4555        return dst - line;
4556}
4557
4558static void patch_id_consume(void *priv, char *line, unsigned long len)
4559{
4560        struct patch_id_t *data = priv;
4561        int new_len;
4562
4563        /* Ignore line numbers when computing the SHA1 of the patch */
4564        if (starts_with(line, "@@ -"))
4565                return;
4566
4567        new_len = remove_space(line, len);
4568
4569        git_SHA1_Update(data->ctx, line, new_len);
4570        data->patchlen += new_len;
4571}
4572
4573static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
4574{
4575        git_SHA1_Update(ctx, str, strlen(str));
4576}
4577
4578static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
4579{
4580        /* large enough for 2^32 in octal */
4581        char buf[12];
4582        int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
4583        git_SHA1_Update(ctx, buf, len);
4584}
4585
4586/* returns 0 upon success, and writes result into sha1 */
4587static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1, int diff_header_only)
4588{
4589        struct diff_queue_struct *q = &diff_queued_diff;
4590        int i;
4591        git_SHA_CTX ctx;
4592        struct patch_id_t data;
4593
4594        git_SHA1_Init(&ctx);
4595        memset(&data, 0, sizeof(struct patch_id_t));
4596        data.ctx = &ctx;
4597
4598        for (i = 0; i < q->nr; i++) {
4599                xpparam_t xpp;
4600                xdemitconf_t xecfg;
4601                mmfile_t mf1, mf2;
4602                struct diff_filepair *p = q->queue[i];
4603                int len1, len2;
4604
4605                memset(&xpp, 0, sizeof(xpp));
4606                memset(&xecfg, 0, sizeof(xecfg));
4607                if (p->status == 0)
4608                        return error("internal diff status error");
4609                if (p->status == DIFF_STATUS_UNKNOWN)
4610                        continue;
4611                if (diff_unmodified_pair(p))
4612                        continue;
4613                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4614                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4615                        continue;
4616                if (DIFF_PAIR_UNMERGED(p))
4617                        continue;
4618
4619                diff_fill_sha1_info(p->one);
4620                diff_fill_sha1_info(p->two);
4621
4622                len1 = remove_space(p->one->path, strlen(p->one->path));
4623                len2 = remove_space(p->two->path, strlen(p->two->path));
4624                patch_id_add_string(&ctx, "diff--git");
4625                patch_id_add_string(&ctx, "a/");
4626                git_SHA1_Update(&ctx, p->one->path, len1);
4627                patch_id_add_string(&ctx, "b/");
4628                git_SHA1_Update(&ctx, p->two->path, len2);
4629
4630                if (p->one->mode == 0) {
4631                        patch_id_add_string(&ctx, "newfilemode");
4632                        patch_id_add_mode(&ctx, p->two->mode);
4633                        patch_id_add_string(&ctx, "---/dev/null");
4634                        patch_id_add_string(&ctx, "+++b/");
4635                        git_SHA1_Update(&ctx, p->two->path, len2);
4636                } else if (p->two->mode == 0) {
4637                        patch_id_add_string(&ctx, "deletedfilemode");
4638                        patch_id_add_mode(&ctx, p->one->mode);
4639                        patch_id_add_string(&ctx, "---a/");
4640                        git_SHA1_Update(&ctx, p->one->path, len1);
4641                        patch_id_add_string(&ctx, "+++/dev/null");
4642                } else {
4643                        patch_id_add_string(&ctx, "---a/");
4644                        git_SHA1_Update(&ctx, p->one->path, len1);
4645                        patch_id_add_string(&ctx, "+++b/");
4646                        git_SHA1_Update(&ctx, p->two->path, len2);
4647                }
4648
4649                if (diff_header_only)
4650                        continue;
4651
4652                if (fill_mmfile(&mf1, p->one) < 0 ||
4653                    fill_mmfile(&mf2, p->two) < 0)
4654                        return error("unable to read files to diff");
4655
4656                if (diff_filespec_is_binary(p->one) ||
4657                    diff_filespec_is_binary(p->two)) {
4658                        git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
4659                                        40);
4660                        git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
4661                                        40);
4662                        continue;
4663                }
4664
4665                xpp.flags = 0;
4666                xecfg.ctxlen = 3;
4667                xecfg.flags = 0;
4668                if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4669                                  &xpp, &xecfg))
4670                        return error("unable to generate patch-id diff for %s",
4671                                     p->one->path);
4672        }
4673
4674        git_SHA1_Final(sha1, &ctx);
4675        return 0;
4676}
4677
4678int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1, int diff_header_only)
4679{
4680        struct diff_queue_struct *q = &diff_queued_diff;
4681        int i;
4682        int result = diff_get_patch_id(options, sha1, diff_header_only);
4683
4684        for (i = 0; i < q->nr; i++)
4685                diff_free_filepair(q->queue[i]);
4686
4687        free(q->queue);
4688        DIFF_QUEUE_CLEAR(q);
4689
4690        return result;
4691}
4692
4693static int is_summary_empty(const struct diff_queue_struct *q)
4694{
4695        int i;
4696
4697        for (i = 0; i < q->nr; i++) {
4698                const struct diff_filepair *p = q->queue[i];
4699
4700                switch (p->status) {
4701                case DIFF_STATUS_DELETED:
4702                case DIFF_STATUS_ADDED:
4703                case DIFF_STATUS_COPIED:
4704                case DIFF_STATUS_RENAMED:
4705                        return 0;
4706                default:
4707                        if (p->score)
4708                                return 0;
4709                        if (p->one->mode && p->two->mode &&
4710                            p->one->mode != p->two->mode)
4711                                return 0;
4712                        break;
4713                }
4714        }
4715        return 1;
4716}
4717
4718static const char rename_limit_warning[] =
4719N_("inexact rename detection was skipped due to too many files.");
4720
4721static const char degrade_cc_to_c_warning[] =
4722N_("only found copies from modified paths due to too many files.");
4723
4724static const char rename_limit_advice[] =
4725N_("you may want to set your %s variable to at least "
4726   "%d and retry the command.");
4727
4728void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4729{
4730        if (degraded_cc)
4731                warning(_(degrade_cc_to_c_warning));
4732        else if (needed)
4733                warning(_(rename_limit_warning));
4734        else
4735                return;
4736        if (0 < needed && needed < 32767)
4737                warning(_(rename_limit_advice), varname, needed);
4738}
4739
4740void diff_flush(struct diff_options *options)
4741{
4742        struct diff_queue_struct *q = &diff_queued_diff;
4743        int i, output_format = options->output_format;
4744        int separator = 0;
4745        int dirstat_by_line = 0;
4746
4747        /*
4748         * Order: raw, stat, summary, patch
4749         * or:    name/name-status/checkdiff (other bits clear)
4750         */
4751        if (!q->nr)
4752                goto free_queue;
4753
4754        if (output_format & (DIFF_FORMAT_RAW |
4755                             DIFF_FORMAT_NAME |
4756                             DIFF_FORMAT_NAME_STATUS |
4757                             DIFF_FORMAT_CHECKDIFF)) {
4758                for (i = 0; i < q->nr; i++) {
4759                        struct diff_filepair *p = q->queue[i];
4760                        if (check_pair_status(p))
4761                                flush_one_pair(p, options);
4762                }
4763                separator++;
4764        }
4765
4766        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4767                dirstat_by_line = 1;
4768
4769        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4770            dirstat_by_line) {
4771                struct diffstat_t diffstat;
4772
4773                memset(&diffstat, 0, sizeof(struct diffstat_t));
4774                for (i = 0; i < q->nr; i++) {
4775                        struct diff_filepair *p = q->queue[i];
4776                        if (check_pair_status(p))
4777                                diff_flush_stat(p, options, &diffstat);
4778                }
4779                if (output_format & DIFF_FORMAT_NUMSTAT)
4780                        show_numstat(&diffstat, options);
4781                if (output_format & DIFF_FORMAT_DIFFSTAT)
4782                        show_stats(&diffstat, options);
4783                if (output_format & DIFF_FORMAT_SHORTSTAT)
4784                        show_shortstats(&diffstat, options);
4785                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4786                        show_dirstat_by_line(&diffstat, options);
4787                free_diffstat_info(&diffstat);
4788                separator++;
4789        }
4790        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4791                show_dirstat(options);
4792
4793        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4794                for (i = 0; i < q->nr; i++) {
4795                        diff_summary(options, q->queue[i]);
4796                }
4797                separator++;
4798        }
4799
4800        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4801            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4802            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4803                /*
4804                 * run diff_flush_patch for the exit status. setting
4805                 * options->file to /dev/null should be safe, because we
4806                 * aren't supposed to produce any output anyway.
4807                 */
4808                if (options->close_file)
4809                        fclose(options->file);
4810                options->file = fopen("/dev/null", "w");
4811                if (!options->file)
4812                        die_errno("Could not open /dev/null");
4813                options->close_file = 1;
4814                for (i = 0; i < q->nr; i++) {
4815                        struct diff_filepair *p = q->queue[i];
4816                        if (check_pair_status(p))
4817                                diff_flush_patch(p, options);
4818                        if (options->found_changes)
4819                                break;
4820                }
4821        }
4822
4823        if (output_format & DIFF_FORMAT_PATCH) {
4824                if (separator) {
4825                        fprintf(options->file, "%s%c",
4826                                diff_line_prefix(options),
4827                                options->line_termination);
4828                        if (options->stat_sep) {
4829                                /* attach patch instead of inline */
4830                                fputs(options->stat_sep, options->file);
4831                        }
4832                }
4833
4834                for (i = 0; i < q->nr; i++) {
4835                        struct diff_filepair *p = q->queue[i];
4836                        if (check_pair_status(p))
4837                                diff_flush_patch(p, options);
4838                }
4839        }
4840
4841        if (output_format & DIFF_FORMAT_CALLBACK)
4842                options->format_callback(q, options, options->format_callback_data);
4843
4844        for (i = 0; i < q->nr; i++)
4845                diff_free_filepair(q->queue[i]);
4846free_queue:
4847        free(q->queue);
4848        DIFF_QUEUE_CLEAR(q);
4849        if (options->close_file)
4850                fclose(options->file);
4851
4852        /*
4853         * Report the content-level differences with HAS_CHANGES;
4854         * diff_addremove/diff_change does not set the bit when
4855         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4856         */
4857        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4858                if (options->found_changes)
4859                        DIFF_OPT_SET(options, HAS_CHANGES);
4860                else
4861                        DIFF_OPT_CLR(options, HAS_CHANGES);
4862        }
4863}
4864
4865static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4866{
4867        return (((p->status == DIFF_STATUS_MODIFIED) &&
4868                 ((p->score &&
4869                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4870                  (!p->score &&
4871                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4872                ((p->status != DIFF_STATUS_MODIFIED) &&
4873                 filter_bit_tst(p->status, options)));
4874}
4875
4876static void diffcore_apply_filter(struct diff_options *options)
4877{
4878        int i;
4879        struct diff_queue_struct *q = &diff_queued_diff;
4880        struct diff_queue_struct outq;
4881
4882        DIFF_QUEUE_CLEAR(&outq);
4883
4884        if (!options->filter)
4885                return;
4886
4887        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4888                int found;
4889                for (i = found = 0; !found && i < q->nr; i++) {
4890                        if (match_filter(options, q->queue[i]))
4891                                found++;
4892                }
4893                if (found)
4894                        return;
4895
4896                /* otherwise we will clear the whole queue
4897                 * by copying the empty outq at the end of this
4898                 * function, but first clear the current entries
4899                 * in the queue.
4900                 */
4901                for (i = 0; i < q->nr; i++)
4902                        diff_free_filepair(q->queue[i]);
4903        }
4904        else {
4905                /* Only the matching ones */
4906                for (i = 0; i < q->nr; i++) {
4907                        struct diff_filepair *p = q->queue[i];
4908                        if (match_filter(options, p))
4909                                diff_q(&outq, p);
4910                        else
4911                                diff_free_filepair(p);
4912                }
4913        }
4914        free(q->queue);
4915        *q = outq;
4916}
4917
4918/* Check whether two filespecs with the same mode and size are identical */
4919static int diff_filespec_is_identical(struct diff_filespec *one,
4920                                      struct diff_filespec *two)
4921{
4922        if (S_ISGITLINK(one->mode))
4923                return 0;
4924        if (diff_populate_filespec(one, 0))
4925                return 0;
4926        if (diff_populate_filespec(two, 0))
4927                return 0;
4928        return !memcmp(one->data, two->data, one->size);
4929}
4930
4931static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4932{
4933        if (p->done_skip_stat_unmatch)
4934                return p->skip_stat_unmatch_result;
4935
4936        p->done_skip_stat_unmatch = 1;
4937        p->skip_stat_unmatch_result = 0;
4938        /*
4939         * 1. Entries that come from stat info dirtiness
4940         *    always have both sides (iow, not create/delete),
4941         *    one side of the object name is unknown, with
4942         *    the same mode and size.  Keep the ones that
4943         *    do not match these criteria.  They have real
4944         *    differences.
4945         *
4946         * 2. At this point, the file is known to be modified,
4947         *    with the same mode and size, and the object
4948         *    name of one side is unknown.  Need to inspect
4949         *    the identical contents.
4950         */
4951        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4952            !DIFF_FILE_VALID(p->two) ||
4953            (p->one->oid_valid && p->two->oid_valid) ||
4954            (p->one->mode != p->two->mode) ||
4955            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4956            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4957            (p->one->size != p->two->size) ||
4958            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4959                p->skip_stat_unmatch_result = 1;
4960        return p->skip_stat_unmatch_result;
4961}
4962
4963static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4964{
4965        int i;
4966        struct diff_queue_struct *q = &diff_queued_diff;
4967        struct diff_queue_struct outq;
4968        DIFF_QUEUE_CLEAR(&outq);
4969
4970        for (i = 0; i < q->nr; i++) {
4971                struct diff_filepair *p = q->queue[i];
4972
4973                if (diff_filespec_check_stat_unmatch(p))
4974                        diff_q(&outq, p);
4975                else {
4976                        /*
4977                         * The caller can subtract 1 from skip_stat_unmatch
4978                         * to determine how many paths were dirty only
4979                         * due to stat info mismatch.
4980                         */
4981                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4982                                diffopt->skip_stat_unmatch++;
4983                        diff_free_filepair(p);
4984                }
4985        }
4986        free(q->queue);
4987        *q = outq;
4988}
4989
4990static int diffnamecmp(const void *a_, const void *b_)
4991{
4992        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4993        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4994        const char *name_a, *name_b;
4995
4996        name_a = a->one ? a->one->path : a->two->path;
4997        name_b = b->one ? b->one->path : b->two->path;
4998        return strcmp(name_a, name_b);
4999}
5000
5001void diffcore_fix_diff_index(struct diff_options *options)
5002{
5003        struct diff_queue_struct *q = &diff_queued_diff;
5004        QSORT(q->queue, q->nr, diffnamecmp);
5005}
5006
5007void diffcore_std(struct diff_options *options)
5008{
5009        /* NOTE please keep the following in sync with diff_tree_combined() */
5010        if (options->skip_stat_unmatch)
5011                diffcore_skip_stat_unmatch(options);
5012        if (!options->found_follow) {
5013                /* See try_to_follow_renames() in tree-diff.c */
5014                if (options->break_opt != -1)
5015                        diffcore_break(options->break_opt);
5016                if (options->detect_rename)
5017                        diffcore_rename(options);
5018                if (options->break_opt != -1)
5019                        diffcore_merge_broken();
5020        }
5021        if (options->pickaxe)
5022                diffcore_pickaxe(options);
5023        if (options->orderfile)
5024                diffcore_order(options->orderfile);
5025        if (!options->found_follow)
5026                /* See try_to_follow_renames() in tree-diff.c */
5027                diff_resolve_rename_copy();
5028        diffcore_apply_filter(options);
5029
5030        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5031                DIFF_OPT_SET(options, HAS_CHANGES);
5032        else
5033                DIFF_OPT_CLR(options, HAS_CHANGES);
5034
5035        options->found_follow = 0;
5036}
5037
5038int diff_result_code(struct diff_options *opt, int status)
5039{
5040        int result = 0;
5041
5042        diff_warn_rename_limit("diff.renameLimit",
5043                               opt->needed_rename_limit,
5044                               opt->degraded_cc_to_c);
5045        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5046            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5047                return status;
5048        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5049            DIFF_OPT_TST(opt, HAS_CHANGES))
5050                result |= 01;
5051        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5052            DIFF_OPT_TST(opt, CHECK_FAILED))
5053                result |= 02;
5054        return result;
5055}
5056
5057int diff_can_quit_early(struct diff_options *opt)
5058{
5059        return (DIFF_OPT_TST(opt, QUICK) &&
5060                !opt->filter &&
5061                DIFF_OPT_TST(opt, HAS_CHANGES));
5062}
5063
5064/*
5065 * Shall changes to this submodule be ignored?
5066 *
5067 * Submodule changes can be configured to be ignored separately for each path,
5068 * but that configuration can be overridden from the command line.
5069 */
5070static int is_submodule_ignored(const char *path, struct diff_options *options)
5071{
5072        int ignored = 0;
5073        unsigned orig_flags = options->flags;
5074        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
5075                set_diffopt_flags_from_submodule_config(options, path);
5076        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
5077                ignored = 1;
5078        options->flags = orig_flags;
5079        return ignored;
5080}
5081
5082void diff_addremove(struct diff_options *options,
5083                    int addremove, unsigned mode,
5084                    const unsigned char *sha1,
5085                    int sha1_valid,
5086                    const char *concatpath, unsigned dirty_submodule)
5087{
5088        struct diff_filespec *one, *two;
5089
5090        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5091                return;
5092
5093        /* This may look odd, but it is a preparation for
5094         * feeding "there are unchanged files which should
5095         * not produce diffs, but when you are doing copy
5096         * detection you would need them, so here they are"
5097         * entries to the diff-core.  They will be prefixed
5098         * with something like '=' or '*' (I haven't decided
5099         * which but should not make any difference).
5100         * Feeding the same new and old to diff_change()
5101         * also has the same effect.
5102         * Before the final output happens, they are pruned after
5103         * merged into rename/copy pairs as appropriate.
5104         */
5105        if (DIFF_OPT_TST(options, REVERSE_DIFF))
5106                addremove = (addremove == '+' ? '-' :
5107                             addremove == '-' ? '+' : addremove);
5108
5109        if (options->prefix &&
5110            strncmp(concatpath, options->prefix, options->prefix_length))
5111                return;
5112
5113        one = alloc_filespec(concatpath);
5114        two = alloc_filespec(concatpath);
5115
5116        if (addremove != '+')
5117                fill_filespec(one, sha1, sha1_valid, mode);
5118        if (addremove != '-') {
5119                fill_filespec(two, sha1, sha1_valid, mode);
5120                two->dirty_submodule = dirty_submodule;
5121        }
5122
5123        diff_queue(&diff_queued_diff, one, two);
5124        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5125                DIFF_OPT_SET(options, HAS_CHANGES);
5126}
5127
5128void diff_change(struct diff_options *options,
5129                 unsigned old_mode, unsigned new_mode,
5130                 const unsigned char *old_sha1,
5131                 const unsigned char *new_sha1,
5132                 int old_sha1_valid, int new_sha1_valid,
5133                 const char *concatpath,
5134                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5135{
5136        struct diff_filespec *one, *two;
5137        struct diff_filepair *p;
5138
5139        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5140            is_submodule_ignored(concatpath, options))
5141                return;
5142
5143        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5144                SWAP(old_mode, new_mode);
5145                SWAP(old_sha1, new_sha1);
5146                SWAP(old_sha1_valid, new_sha1_valid);
5147                SWAP(old_dirty_submodule, new_dirty_submodule);
5148        }
5149
5150        if (options->prefix &&
5151            strncmp(concatpath, options->prefix, options->prefix_length))
5152                return;
5153
5154        one = alloc_filespec(concatpath);
5155        two = alloc_filespec(concatpath);
5156        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
5157        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
5158        one->dirty_submodule = old_dirty_submodule;
5159        two->dirty_submodule = new_dirty_submodule;
5160        p = diff_queue(&diff_queued_diff, one, two);
5161
5162        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5163                return;
5164
5165        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5166            !diff_filespec_check_stat_unmatch(p))
5167                return;
5168
5169        DIFF_OPT_SET(options, HAS_CHANGES);
5170}
5171
5172struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5173{
5174        struct diff_filepair *pair;
5175        struct diff_filespec *one, *two;
5176
5177        if (options->prefix &&
5178            strncmp(path, options->prefix, options->prefix_length))
5179                return NULL;
5180
5181        one = alloc_filespec(path);
5182        two = alloc_filespec(path);
5183        pair = diff_queue(&diff_queued_diff, one, two);
5184        pair->is_unmerged = 1;
5185        return pair;
5186}
5187
5188static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5189                size_t *outsize)
5190{
5191        struct diff_tempfile *temp;
5192        const char *argv[3];
5193        const char **arg = argv;
5194        struct child_process child = CHILD_PROCESS_INIT;
5195        struct strbuf buf = STRBUF_INIT;
5196        int err = 0;
5197
5198        temp = prepare_temp_file(spec->path, spec);
5199        *arg++ = pgm;
5200        *arg++ = temp->name;
5201        *arg = NULL;
5202
5203        child.use_shell = 1;
5204        child.argv = argv;
5205        child.out = -1;
5206        if (start_command(&child)) {
5207                remove_tempfile();
5208                return NULL;
5209        }
5210
5211        if (strbuf_read(&buf, child.out, 0) < 0)
5212                err = error("error reading from textconv command '%s'", pgm);
5213        close(child.out);
5214
5215        if (finish_command(&child) || err) {
5216                strbuf_release(&buf);
5217                remove_tempfile();
5218                return NULL;
5219        }
5220        remove_tempfile();
5221
5222        return strbuf_detach(&buf, outsize);
5223}
5224
5225size_t fill_textconv(struct userdiff_driver *driver,
5226                     struct diff_filespec *df,
5227                     char **outbuf)
5228{
5229        size_t size;
5230
5231        if (!driver) {
5232                if (!DIFF_FILE_VALID(df)) {
5233                        *outbuf = "";
5234                        return 0;
5235                }
5236                if (diff_populate_filespec(df, 0))
5237                        die("unable to read files to diff");
5238                *outbuf = df->data;
5239                return df->size;
5240        }
5241
5242        if (!driver->textconv)
5243                die("BUG: fill_textconv called with non-textconv driver");
5244
5245        if (driver->textconv_cache && df->oid_valid) {
5246                *outbuf = notes_cache_get(driver->textconv_cache,
5247                                          df->oid.hash,
5248                                          &size);
5249                if (*outbuf)
5250                        return size;
5251        }
5252
5253        *outbuf = run_textconv(driver->textconv, df, &size);
5254        if (!*outbuf)
5255                die("unable to read files to diff");
5256
5257        if (driver->textconv_cache && df->oid_valid) {
5258                /* ignore errors, as we might be in a readonly repository */
5259                notes_cache_put(driver->textconv_cache, df->oid.hash, *outbuf,
5260                                size);
5261                /*
5262                 * we could save up changes and flush them all at the end,
5263                 * but we would need an extra call after all diffing is done.
5264                 * Since generating a cache entry is the slow path anyway,
5265                 * this extra overhead probably isn't a big deal.
5266                 */
5267                notes_cache_write(driver->textconv_cache);
5268        }
5269
5270        return size;
5271}
5272
5273void setup_diff_pager(struct diff_options *opt)
5274{
5275        /*
5276         * If the user asked for our exit code, then either they want --quiet
5277         * or --exit-code. We should definitely not bother with a pager in the
5278         * former case, as we will generate no output. Since we still properly
5279         * report our exit code even when a pager is run, we _could_ run a
5280         * pager with --exit-code. But since we have not done so historically,
5281         * and because it is easy to find people oneline advising "git diff
5282         * --exit-code" in hooks and other scripts, we do not do so.
5283         */
5284        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5285            check_pager_config("diff") != 0)
5286                setup_pager();
5287}