diff.con commit Merge branch 'jc/forbid-symbolic-ref-d-HEAD' (d1de693)
   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_compaction_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 const char *diff_word_regex_cfg;
  36static const char *external_diff_cmd_cfg;
  37static const char *diff_order_file_cfg;
  38int diff_auto_refresh_index = 1;
  39static int diff_mnemonic_prefix;
  40static int diff_no_prefix;
  41static int diff_stat_graph_width;
  42static int diff_dirstat_permille_default = 30;
  43static struct diff_options default_diff_options;
  44static long diff_algorithm;
  45
  46static char diff_colors[][COLOR_MAXLEN] = {
  47        GIT_COLOR_RESET,
  48        GIT_COLOR_NORMAL,       /* CONTEXT */
  49        GIT_COLOR_BOLD,         /* METAINFO */
  50        GIT_COLOR_CYAN,         /* FRAGINFO */
  51        GIT_COLOR_RED,          /* OLD */
  52        GIT_COLOR_GREEN,        /* NEW */
  53        GIT_COLOR_YELLOW,       /* COMMIT */
  54        GIT_COLOR_BG_RED,       /* WHITESPACE */
  55        GIT_COLOR_NORMAL,       /* FUNCINFO */
  56};
  57
  58static int parse_diff_color_slot(const char *var)
  59{
  60        if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  61                return DIFF_CONTEXT;
  62        if (!strcasecmp(var, "meta"))
  63                return DIFF_METAINFO;
  64        if (!strcasecmp(var, "frag"))
  65                return DIFF_FRAGINFO;
  66        if (!strcasecmp(var, "old"))
  67                return DIFF_FILE_OLD;
  68        if (!strcasecmp(var, "new"))
  69                return DIFF_FILE_NEW;
  70        if (!strcasecmp(var, "commit"))
  71                return DIFF_COMMIT;
  72        if (!strcasecmp(var, "whitespace"))
  73                return DIFF_WHITESPACE;
  74        if (!strcasecmp(var, "func"))
  75                return DIFF_FUNCINFO;
  76        return -1;
  77}
  78
  79static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  80                                struct strbuf *errmsg)
  81{
  82        char *params_copy = xstrdup(params_string);
  83        struct string_list params = STRING_LIST_INIT_NODUP;
  84        int ret = 0;
  85        int i;
  86
  87        if (*params_copy)
  88                string_list_split_in_place(&params, params_copy, ',', -1);
  89        for (i = 0; i < params.nr; i++) {
  90                const char *p = params.items[i].string;
  91                if (!strcmp(p, "changes")) {
  92                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  93                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  94                } else if (!strcmp(p, "lines")) {
  95                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  96                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  97                } else if (!strcmp(p, "files")) {
  98                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  99                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
 100                } else if (!strcmp(p, "noncumulative")) {
 101                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 102                } else if (!strcmp(p, "cumulative")) {
 103                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 104                } else if (isdigit(*p)) {
 105                        char *end;
 106                        int permille = strtoul(p, &end, 10) * 10;
 107                        if (*end == '.' && isdigit(*++end)) {
 108                                /* only use first digit */
 109                                permille += *end - '0';
 110                                /* .. and ignore any further digits */
 111                                while (isdigit(*++end))
 112                                        ; /* nothing */
 113                        }
 114                        if (!*end)
 115                                options->dirstat_permille = permille;
 116                        else {
 117                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 118                                            p);
 119                                ret++;
 120                        }
 121                } else {
 122                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 123                        ret++;
 124                }
 125
 126        }
 127        string_list_clear(&params, 0);
 128        free(params_copy);
 129        return ret;
 130}
 131
 132static int parse_submodule_params(struct diff_options *options, const char *value)
 133{
 134        if (!strcmp(value, "log"))
 135                options->submodule_format = DIFF_SUBMODULE_LOG;
 136        else if (!strcmp(value, "short"))
 137                options->submodule_format = DIFF_SUBMODULE_SHORT;
 138        else if (!strcmp(value, "diff"))
 139                options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 140        else
 141                return -1;
 142        return 0;
 143}
 144
 145static int git_config_rename(const char *var, const char *value)
 146{
 147        if (!value)
 148                return DIFF_DETECT_RENAME;
 149        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 150                return  DIFF_DETECT_COPY;
 151        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 152}
 153
 154long parse_algorithm_value(const char *value)
 155{
 156        if (!value)
 157                return -1;
 158        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 159                return 0;
 160        else if (!strcasecmp(value, "minimal"))
 161                return XDF_NEED_MINIMAL;
 162        else if (!strcasecmp(value, "patience"))
 163                return XDF_PATIENCE_DIFF;
 164        else if (!strcasecmp(value, "histogram"))
 165                return XDF_HISTOGRAM_DIFF;
 166        return -1;
 167}
 168
 169/*
 170 * These are to give UI layer defaults.
 171 * The core-level commands such as git-diff-files should
 172 * never be affected by the setting of diff.renames
 173 * the user happens to have in the configuration file.
 174 */
 175void init_diff_ui_defaults(void)
 176{
 177        diff_detect_rename_default = 1;
 178}
 179
 180int git_diff_ui_config(const char *var, const char *value, void *cb)
 181{
 182        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 183                diff_use_color_default = git_config_colorbool(var, value);
 184                return 0;
 185        }
 186        if (!strcmp(var, "diff.context")) {
 187                diff_context_default = git_config_int(var, value);
 188                if (diff_context_default < 0)
 189                        return -1;
 190                return 0;
 191        }
 192        if (!strcmp(var, "diff.renames")) {
 193                diff_detect_rename_default = git_config_rename(var, value);
 194                return 0;
 195        }
 196        if (!strcmp(var, "diff.compactionheuristic")) {
 197                diff_compaction_heuristic = git_config_bool(var, value);
 198                return 0;
 199        }
 200        if (!strcmp(var, "diff.autorefreshindex")) {
 201                diff_auto_refresh_index = git_config_bool(var, value);
 202                return 0;
 203        }
 204        if (!strcmp(var, "diff.mnemonicprefix")) {
 205                diff_mnemonic_prefix = git_config_bool(var, value);
 206                return 0;
 207        }
 208        if (!strcmp(var, "diff.noprefix")) {
 209                diff_no_prefix = git_config_bool(var, value);
 210                return 0;
 211        }
 212        if (!strcmp(var, "diff.statgraphwidth")) {
 213                diff_stat_graph_width = git_config_int(var, value);
 214                return 0;
 215        }
 216        if (!strcmp(var, "diff.external"))
 217                return git_config_string(&external_diff_cmd_cfg, var, value);
 218        if (!strcmp(var, "diff.wordregex"))
 219                return git_config_string(&diff_word_regex_cfg, var, value);
 220        if (!strcmp(var, "diff.orderfile"))
 221                return git_config_pathname(&diff_order_file_cfg, var, value);
 222
 223        if (!strcmp(var, "diff.ignoresubmodules"))
 224                handle_ignore_submodules_arg(&default_diff_options, value);
 225
 226        if (!strcmp(var, "diff.submodule")) {
 227                if (parse_submodule_params(&default_diff_options, value))
 228                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 229                                value);
 230                return 0;
 231        }
 232
 233        if (!strcmp(var, "diff.algorithm")) {
 234                diff_algorithm = parse_algorithm_value(value);
 235                if (diff_algorithm < 0)
 236                        return -1;
 237                return 0;
 238        }
 239
 240        if (git_color_config(var, value, cb) < 0)
 241                return -1;
 242
 243        return git_diff_basic_config(var, value, cb);
 244}
 245
 246int git_diff_basic_config(const char *var, const char *value, void *cb)
 247{
 248        const char *name;
 249
 250        if (!strcmp(var, "diff.renamelimit")) {
 251                diff_rename_limit_default = git_config_int(var, value);
 252                return 0;
 253        }
 254
 255        if (userdiff_config(var, value) < 0)
 256                return -1;
 257
 258        if (skip_prefix(var, "diff.color.", &name) ||
 259            skip_prefix(var, "color.diff.", &name)) {
 260                int slot = parse_diff_color_slot(name);
 261                if (slot < 0)
 262                        return 0;
 263                if (!value)
 264                        return config_error_nonbool(var);
 265                return color_parse(value, diff_colors[slot]);
 266        }
 267
 268        /* like GNU diff's --suppress-blank-empty option  */
 269        if (!strcmp(var, "diff.suppressblankempty") ||
 270                        /* for backwards compatibility */
 271                        !strcmp(var, "diff.suppress-blank-empty")) {
 272                diff_suppress_blank_empty = git_config_bool(var, value);
 273                return 0;
 274        }
 275
 276        if (!strcmp(var, "diff.dirstat")) {
 277                struct strbuf errmsg = STRBUF_INIT;
 278                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 279                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 280                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 281                                errmsg.buf);
 282                strbuf_release(&errmsg);
 283                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 284                return 0;
 285        }
 286
 287        if (starts_with(var, "submodule."))
 288                return parse_submodule_config_option(var, value);
 289
 290        return git_default_config(var, value, cb);
 291}
 292
 293static char *quote_two(const char *one, const char *two)
 294{
 295        int need_one = quote_c_style(one, NULL, NULL, 1);
 296        int need_two = quote_c_style(two, NULL, NULL, 1);
 297        struct strbuf res = STRBUF_INIT;
 298
 299        if (need_one + need_two) {
 300                strbuf_addch(&res, '"');
 301                quote_c_style(one, &res, NULL, 1);
 302                quote_c_style(two, &res, NULL, 1);
 303                strbuf_addch(&res, '"');
 304        } else {
 305                strbuf_addstr(&res, one);
 306                strbuf_addstr(&res, two);
 307        }
 308        return strbuf_detach(&res, NULL);
 309}
 310
 311static const char *external_diff(void)
 312{
 313        static const char *external_diff_cmd = NULL;
 314        static int done_preparing = 0;
 315
 316        if (done_preparing)
 317                return external_diff_cmd;
 318        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 319        if (!external_diff_cmd)
 320                external_diff_cmd = external_diff_cmd_cfg;
 321        done_preparing = 1;
 322        return external_diff_cmd;
 323}
 324
 325/*
 326 * Keep track of files used for diffing. Sometimes such an entry
 327 * refers to a temporary file, sometimes to an existing file, and
 328 * sometimes to "/dev/null".
 329 */
 330static struct diff_tempfile {
 331        /*
 332         * filename external diff should read from, or NULL if this
 333         * entry is currently not in use:
 334         */
 335        const char *name;
 336
 337        char hex[GIT_SHA1_HEXSZ + 1];
 338        char mode[10];
 339
 340        /*
 341         * If this diff_tempfile instance refers to a temporary file,
 342         * this tempfile object is used to manage its lifetime.
 343         */
 344        struct tempfile tempfile;
 345} diff_temp[2];
 346
 347typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 348
 349struct emit_callback {
 350        int color_diff;
 351        unsigned ws_rule;
 352        int blank_at_eof_in_preimage;
 353        int blank_at_eof_in_postimage;
 354        int lno_in_preimage;
 355        int lno_in_postimage;
 356        sane_truncate_fn truncate;
 357        const char **label_path;
 358        struct diff_words_data *diff_words;
 359        struct diff_options *opt;
 360        int *found_changesp;
 361        struct strbuf *header;
 362};
 363
 364static int count_lines(const char *data, int size)
 365{
 366        int count, ch, completely_empty = 1, nl_just_seen = 0;
 367        count = 0;
 368        while (0 < size--) {
 369                ch = *data++;
 370                if (ch == '\n') {
 371                        count++;
 372                        nl_just_seen = 1;
 373                        completely_empty = 0;
 374                }
 375                else {
 376                        nl_just_seen = 0;
 377                        completely_empty = 0;
 378                }
 379        }
 380        if (completely_empty)
 381                return 0;
 382        if (!nl_just_seen)
 383                count++; /* no trailing newline */
 384        return count;
 385}
 386
 387static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 388{
 389        if (!DIFF_FILE_VALID(one)) {
 390                mf->ptr = (char *)""; /* does not matter */
 391                mf->size = 0;
 392                return 0;
 393        }
 394        else if (diff_populate_filespec(one, 0))
 395                return -1;
 396
 397        mf->ptr = one->data;
 398        mf->size = one->size;
 399        return 0;
 400}
 401
 402/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 403static unsigned long diff_filespec_size(struct diff_filespec *one)
 404{
 405        if (!DIFF_FILE_VALID(one))
 406                return 0;
 407        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 408        return one->size;
 409}
 410
 411static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 412{
 413        char *ptr = mf->ptr;
 414        long size = mf->size;
 415        int cnt = 0;
 416
 417        if (!size)
 418                return cnt;
 419        ptr += size - 1; /* pointing at the very end */
 420        if (*ptr != '\n')
 421                ; /* incomplete line */
 422        else
 423                ptr--; /* skip the last LF */
 424        while (mf->ptr < ptr) {
 425                char *prev_eol;
 426                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 427                        if (*prev_eol == '\n')
 428                                break;
 429                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 430                        break;
 431                cnt++;
 432                ptr = prev_eol - 1;
 433        }
 434        return cnt;
 435}
 436
 437static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 438                               struct emit_callback *ecbdata)
 439{
 440        int l1, l2, at;
 441        unsigned ws_rule = ecbdata->ws_rule;
 442        l1 = count_trailing_blank(mf1, ws_rule);
 443        l2 = count_trailing_blank(mf2, ws_rule);
 444        if (l2 <= l1) {
 445                ecbdata->blank_at_eof_in_preimage = 0;
 446                ecbdata->blank_at_eof_in_postimage = 0;
 447                return;
 448        }
 449        at = count_lines(mf1->ptr, mf1->size);
 450        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 451
 452        at = count_lines(mf2->ptr, mf2->size);
 453        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 454}
 455
 456static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 457                        int first, const char *line, int len)
 458{
 459        int has_trailing_newline, has_trailing_carriage_return;
 460        int nofirst;
 461        FILE *file = o->file;
 462
 463        fputs(diff_line_prefix(o), file);
 464
 465        if (len == 0) {
 466                has_trailing_newline = (first == '\n');
 467                has_trailing_carriage_return = (!has_trailing_newline &&
 468                                                (first == '\r'));
 469                nofirst = has_trailing_newline || has_trailing_carriage_return;
 470        } else {
 471                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 472                if (has_trailing_newline)
 473                        len--;
 474                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 475                if (has_trailing_carriage_return)
 476                        len--;
 477                nofirst = 0;
 478        }
 479
 480        if (len || !nofirst) {
 481                fputs(set, file);
 482                if (!nofirst)
 483                        fputc(first, file);
 484                fwrite(line, len, 1, file);
 485                fputs(reset, file);
 486        }
 487        if (has_trailing_carriage_return)
 488                fputc('\r', file);
 489        if (has_trailing_newline)
 490                fputc('\n', file);
 491}
 492
 493static void emit_line(struct diff_options *o, const char *set, const char *reset,
 494                      const char *line, int len)
 495{
 496        emit_line_0(o, set, reset, line[0], line+1, len-1);
 497}
 498
 499static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 500{
 501        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 502              ecbdata->blank_at_eof_in_preimage &&
 503              ecbdata->blank_at_eof_in_postimage &&
 504              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 505              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 506                return 0;
 507        return ws_blank_line(line, len, ecbdata->ws_rule);
 508}
 509
 510static void emit_line_checked(const char *reset,
 511                              struct emit_callback *ecbdata,
 512                              const char *line, int len,
 513                              enum color_diff color,
 514                              unsigned ws_error_highlight,
 515                              char sign)
 516{
 517        const char *set = diff_get_color(ecbdata->color_diff, color);
 518        const char *ws = NULL;
 519
 520        if (ecbdata->opt->ws_error_highlight & ws_error_highlight) {
 521                ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 522                if (!*ws)
 523                        ws = NULL;
 524        }
 525
 526        if (!ws)
 527                emit_line_0(ecbdata->opt, set, reset, sign, line, len);
 528        else if (sign == '+' && new_blank_line_at_eof(ecbdata, line, len))
 529                /* Blank line at EOF - paint '+' as well */
 530                emit_line_0(ecbdata->opt, ws, reset, sign, line, len);
 531        else {
 532                /* Emit just the prefix, then the rest. */
 533                emit_line_0(ecbdata->opt, set, reset, sign, "", 0);
 534                ws_check_emit(line, len, ecbdata->ws_rule,
 535                              ecbdata->opt->file, set, reset, ws);
 536        }
 537}
 538
 539static void emit_add_line(const char *reset,
 540                          struct emit_callback *ecbdata,
 541                          const char *line, int len)
 542{
 543        emit_line_checked(reset, ecbdata, line, len,
 544                          DIFF_FILE_NEW, WSEH_NEW, '+');
 545}
 546
 547static void emit_del_line(const char *reset,
 548                          struct emit_callback *ecbdata,
 549                          const char *line, int len)
 550{
 551        emit_line_checked(reset, ecbdata, line, len,
 552                          DIFF_FILE_OLD, WSEH_OLD, '-');
 553}
 554
 555static void emit_context_line(const char *reset,
 556                              struct emit_callback *ecbdata,
 557                              const char *line, int len)
 558{
 559        emit_line_checked(reset, ecbdata, line, len,
 560                          DIFF_CONTEXT, WSEH_CONTEXT, ' ');
 561}
 562
 563static void emit_hunk_header(struct emit_callback *ecbdata,
 564                             const char *line, int len)
 565{
 566        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 567        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 568        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 569        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 570        static const char atat[2] = { '@', '@' };
 571        const char *cp, *ep;
 572        struct strbuf msgbuf = STRBUF_INIT;
 573        int org_len = len;
 574        int i = 1;
 575
 576        /*
 577         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 578         * it always is at least 10 bytes long.
 579         */
 580        if (len < 10 ||
 581            memcmp(line, atat, 2) ||
 582            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 583                emit_line(ecbdata->opt, context, reset, line, len);
 584                return;
 585        }
 586        ep += 2; /* skip over @@ */
 587
 588        /* The hunk header in fraginfo color */
 589        strbuf_addstr(&msgbuf, frag);
 590        strbuf_add(&msgbuf, line, ep - line);
 591        strbuf_addstr(&msgbuf, reset);
 592
 593        /*
 594         * trailing "\r\n"
 595         */
 596        for ( ; i < 3; i++)
 597                if (line[len - i] == '\r' || line[len - i] == '\n')
 598                        len--;
 599
 600        /* blank before the func header */
 601        for (cp = ep; ep - line < len; ep++)
 602                if (*ep != ' ' && *ep != '\t')
 603                        break;
 604        if (ep != cp) {
 605                strbuf_addstr(&msgbuf, context);
 606                strbuf_add(&msgbuf, cp, ep - cp);
 607                strbuf_addstr(&msgbuf, reset);
 608        }
 609
 610        if (ep < line + len) {
 611                strbuf_addstr(&msgbuf, func);
 612                strbuf_add(&msgbuf, ep, line + len - ep);
 613                strbuf_addstr(&msgbuf, reset);
 614        }
 615
 616        strbuf_add(&msgbuf, line + len, org_len - len);
 617        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 618        strbuf_release(&msgbuf);
 619}
 620
 621static struct diff_tempfile *claim_diff_tempfile(void) {
 622        int i;
 623        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 624                if (!diff_temp[i].name)
 625                        return diff_temp + i;
 626        die("BUG: diff is failing to clean up its tempfiles");
 627}
 628
 629static void remove_tempfile(void)
 630{
 631        int i;
 632        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 633                if (is_tempfile_active(&diff_temp[i].tempfile))
 634                        delete_tempfile(&diff_temp[i].tempfile);
 635                diff_temp[i].name = NULL;
 636        }
 637}
 638
 639static void print_line_count(FILE *file, int count)
 640{
 641        switch (count) {
 642        case 0:
 643                fprintf(file, "0,0");
 644                break;
 645        case 1:
 646                fprintf(file, "1");
 647                break;
 648        default:
 649                fprintf(file, "1,%d", count);
 650                break;
 651        }
 652}
 653
 654static void emit_rewrite_lines(struct emit_callback *ecb,
 655                               int prefix, const char *data, int size)
 656{
 657        const char *endp = NULL;
 658        static const char *nneof = " No newline at end of file\n";
 659        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 660
 661        while (0 < size) {
 662                int len;
 663
 664                endp = memchr(data, '\n', size);
 665                len = endp ? (endp - data + 1) : size;
 666                if (prefix != '+') {
 667                        ecb->lno_in_preimage++;
 668                        emit_del_line(reset, ecb, data, len);
 669                } else {
 670                        ecb->lno_in_postimage++;
 671                        emit_add_line(reset, ecb, data, len);
 672                }
 673                size -= len;
 674                data += len;
 675        }
 676        if (!endp) {
 677                const char *context = diff_get_color(ecb->color_diff,
 678                                                     DIFF_CONTEXT);
 679                putc('\n', ecb->opt->file);
 680                emit_line_0(ecb->opt, context, reset, '\\',
 681                            nneof, strlen(nneof));
 682        }
 683}
 684
 685static void emit_rewrite_diff(const char *name_a,
 686                              const char *name_b,
 687                              struct diff_filespec *one,
 688                              struct diff_filespec *two,
 689                              struct userdiff_driver *textconv_one,
 690                              struct userdiff_driver *textconv_two,
 691                              struct diff_options *o)
 692{
 693        int lc_a, lc_b;
 694        const char *name_a_tab, *name_b_tab;
 695        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 696        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 697        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 698        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 699        const char *a_prefix, *b_prefix;
 700        char *data_one, *data_two;
 701        size_t size_one, size_two;
 702        struct emit_callback ecbdata;
 703        const char *line_prefix = diff_line_prefix(o);
 704
 705        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 706                a_prefix = o->b_prefix;
 707                b_prefix = o->a_prefix;
 708        } else {
 709                a_prefix = o->a_prefix;
 710                b_prefix = o->b_prefix;
 711        }
 712
 713        name_a += (*name_a == '/');
 714        name_b += (*name_b == '/');
 715        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 716        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 717
 718        strbuf_reset(&a_name);
 719        strbuf_reset(&b_name);
 720        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 721        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 722
 723        size_one = fill_textconv(textconv_one, one, &data_one);
 724        size_two = fill_textconv(textconv_two, two, &data_two);
 725
 726        memset(&ecbdata, 0, sizeof(ecbdata));
 727        ecbdata.color_diff = want_color(o->use_color);
 728        ecbdata.found_changesp = &o->found_changes;
 729        ecbdata.ws_rule = whitespace_rule(name_b);
 730        ecbdata.opt = o;
 731        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 732                mmfile_t mf1, mf2;
 733                mf1.ptr = (char *)data_one;
 734                mf2.ptr = (char *)data_two;
 735                mf1.size = size_one;
 736                mf2.size = size_two;
 737                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 738        }
 739        ecbdata.lno_in_preimage = 1;
 740        ecbdata.lno_in_postimage = 1;
 741
 742        lc_a = count_lines(data_one, size_one);
 743        lc_b = count_lines(data_two, size_two);
 744        fprintf(o->file,
 745                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 746                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 747                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 748                line_prefix, fraginfo);
 749        if (!o->irreversible_delete)
 750                print_line_count(o->file, lc_a);
 751        else
 752                fprintf(o->file, "?,?");
 753        fprintf(o->file, " +");
 754        print_line_count(o->file, lc_b);
 755        fprintf(o->file, " @@%s\n", reset);
 756        if (lc_a && !o->irreversible_delete)
 757                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 758        if (lc_b)
 759                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 760        if (textconv_one)
 761                free((char *)data_one);
 762        if (textconv_two)
 763                free((char *)data_two);
 764}
 765
 766struct diff_words_buffer {
 767        mmfile_t text;
 768        long alloc;
 769        struct diff_words_orig {
 770                const char *begin, *end;
 771        } *orig;
 772        int orig_nr, orig_alloc;
 773};
 774
 775static void diff_words_append(char *line, unsigned long len,
 776                struct diff_words_buffer *buffer)
 777{
 778        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 779        line++;
 780        len--;
 781        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 782        buffer->text.size += len;
 783        buffer->text.ptr[buffer->text.size] = '\0';
 784}
 785
 786struct diff_words_style_elem {
 787        const char *prefix;
 788        const char *suffix;
 789        const char *color; /* NULL; filled in by the setup code if
 790                            * color is enabled */
 791};
 792
 793struct diff_words_style {
 794        enum diff_words_type type;
 795        struct diff_words_style_elem new, old, ctx;
 796        const char *newline;
 797};
 798
 799static struct diff_words_style diff_words_styles[] = {
 800        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 801        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 802        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 803};
 804
 805struct diff_words_data {
 806        struct diff_words_buffer minus, plus;
 807        const char *current_plus;
 808        int last_minus;
 809        struct diff_options *opt;
 810        regex_t *word_regex;
 811        enum diff_words_type type;
 812        struct diff_words_style *style;
 813};
 814
 815static int fn_out_diff_words_write_helper(FILE *fp,
 816                                          struct diff_words_style_elem *st_el,
 817                                          const char *newline,
 818                                          size_t count, const char *buf,
 819                                          const char *line_prefix)
 820{
 821        int print = 0;
 822
 823        while (count) {
 824                char *p = memchr(buf, '\n', count);
 825                if (print)
 826                        fputs(line_prefix, fp);
 827                if (p != buf) {
 828                        if (st_el->color && fputs(st_el->color, fp) < 0)
 829                                return -1;
 830                        if (fputs(st_el->prefix, fp) < 0 ||
 831                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 832                            fputs(st_el->suffix, fp) < 0)
 833                                return -1;
 834                        if (st_el->color && *st_el->color
 835                            && fputs(GIT_COLOR_RESET, fp) < 0)
 836                                return -1;
 837                }
 838                if (!p)
 839                        return 0;
 840                if (fputs(newline, fp) < 0)
 841                        return -1;
 842                count -= p + 1 - buf;
 843                buf = p + 1;
 844                print = 1;
 845        }
 846        return 0;
 847}
 848
 849/*
 850 * '--color-words' algorithm can be described as:
 851 *
 852 *   1. collect a the minus/plus lines of a diff hunk, divided into
 853 *      minus-lines and plus-lines;
 854 *
 855 *   2. break both minus-lines and plus-lines into words and
 856 *      place them into two mmfile_t with one word for each line;
 857 *
 858 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 859 *
 860 * And for the common parts of the both file, we output the plus side text.
 861 * diff_words->current_plus is used to trace the current position of the plus file
 862 * which printed. diff_words->last_minus is used to trace the last minus word
 863 * printed.
 864 *
 865 * For '--graph' to work with '--color-words', we need to output the graph prefix
 866 * on each line of color words output. Generally, there are two conditions on
 867 * which we should output the prefix.
 868 *
 869 *   1. diff_words->last_minus == 0 &&
 870 *      diff_words->current_plus == diff_words->plus.text.ptr
 871 *
 872 *      that is: the plus text must start as a new line, and if there is no minus
 873 *      word printed, a graph prefix must be printed.
 874 *
 875 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 876 *      *(diff_words->current_plus - 1) == '\n'
 877 *
 878 *      that is: a graph prefix must be printed following a '\n'
 879 */
 880static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 881{
 882        if ((diff_words->last_minus == 0 &&
 883                diff_words->current_plus == diff_words->plus.text.ptr) ||
 884                (diff_words->current_plus > diff_words->plus.text.ptr &&
 885                *(diff_words->current_plus - 1) == '\n')) {
 886                return 1;
 887        } else {
 888                return 0;
 889        }
 890}
 891
 892static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 893{
 894        struct diff_words_data *diff_words = priv;
 895        struct diff_words_style *style = diff_words->style;
 896        int minus_first, minus_len, plus_first, plus_len;
 897        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 898        struct diff_options *opt = diff_words->opt;
 899        const char *line_prefix;
 900
 901        if (line[0] != '@' || parse_hunk_header(line, len,
 902                        &minus_first, &minus_len, &plus_first, &plus_len))
 903                return;
 904
 905        assert(opt);
 906        line_prefix = diff_line_prefix(opt);
 907
 908        /* POSIX requires that first be decremented by one if len == 0... */
 909        if (minus_len) {
 910                minus_begin = diff_words->minus.orig[minus_first].begin;
 911                minus_end =
 912                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 913        } else
 914                minus_begin = minus_end =
 915                        diff_words->minus.orig[minus_first].end;
 916
 917        if (plus_len) {
 918                plus_begin = diff_words->plus.orig[plus_first].begin;
 919                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 920        } else
 921                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 922
 923        if (color_words_output_graph_prefix(diff_words)) {
 924                fputs(line_prefix, diff_words->opt->file);
 925        }
 926        if (diff_words->current_plus != plus_begin) {
 927                fn_out_diff_words_write_helper(diff_words->opt->file,
 928                                &style->ctx, style->newline,
 929                                plus_begin - diff_words->current_plus,
 930                                diff_words->current_plus, line_prefix);
 931                if (*(plus_begin - 1) == '\n')
 932                        fputs(line_prefix, diff_words->opt->file);
 933        }
 934        if (minus_begin != minus_end) {
 935                fn_out_diff_words_write_helper(diff_words->opt->file,
 936                                &style->old, style->newline,
 937                                minus_end - minus_begin, minus_begin,
 938                                line_prefix);
 939        }
 940        if (plus_begin != plus_end) {
 941                fn_out_diff_words_write_helper(diff_words->opt->file,
 942                                &style->new, style->newline,
 943                                plus_end - plus_begin, plus_begin,
 944                                line_prefix);
 945        }
 946
 947        diff_words->current_plus = plus_end;
 948        diff_words->last_minus = minus_first;
 949}
 950
 951/* This function starts looking at *begin, and returns 0 iff a word was found. */
 952static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 953                int *begin, int *end)
 954{
 955        if (word_regex && *begin < buffer->size) {
 956                regmatch_t match[1];
 957                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 958                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 959                                        '\n', match[0].rm_eo - match[0].rm_so);
 960                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 961                        *begin += match[0].rm_so;
 962                        return *begin >= *end;
 963                }
 964                return -1;
 965        }
 966
 967        /* find the next word */
 968        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 969                (*begin)++;
 970        if (*begin >= buffer->size)
 971                return -1;
 972
 973        /* find the end of the word */
 974        *end = *begin + 1;
 975        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 976                (*end)++;
 977
 978        return 0;
 979}
 980
 981/*
 982 * This function splits the words in buffer->text, stores the list with
 983 * newline separator into out, and saves the offsets of the original words
 984 * in buffer->orig.
 985 */
 986static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 987                regex_t *word_regex)
 988{
 989        int i, j;
 990        long alloc = 0;
 991
 992        out->size = 0;
 993        out->ptr = NULL;
 994
 995        /* fake an empty "0th" word */
 996        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 997        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 998        buffer->orig_nr = 1;
 999
1000        for (i = 0; i < buffer->text.size; i++) {
1001                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1002                        return;
1003
1004                /* store original boundaries */
1005                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1006                                buffer->orig_alloc);
1007                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1008                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1009                buffer->orig_nr++;
1010
1011                /* store one word */
1012                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1013                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1014                out->ptr[out->size + j - i] = '\n';
1015                out->size += j - i + 1;
1016
1017                i = j - 1;
1018        }
1019}
1020
1021/* this executes the word diff on the accumulated buffers */
1022static void diff_words_show(struct diff_words_data *diff_words)
1023{
1024        xpparam_t xpp;
1025        xdemitconf_t xecfg;
1026        mmfile_t minus, plus;
1027        struct diff_words_style *style = diff_words->style;
1028
1029        struct diff_options *opt = diff_words->opt;
1030        const char *line_prefix;
1031
1032        assert(opt);
1033        line_prefix = diff_line_prefix(opt);
1034
1035        /* special case: only removal */
1036        if (!diff_words->plus.text.size) {
1037                fputs(line_prefix, diff_words->opt->file);
1038                fn_out_diff_words_write_helper(diff_words->opt->file,
1039                        &style->old, style->newline,
1040                        diff_words->minus.text.size,
1041                        diff_words->minus.text.ptr, line_prefix);
1042                diff_words->minus.text.size = 0;
1043                return;
1044        }
1045
1046        diff_words->current_plus = diff_words->plus.text.ptr;
1047        diff_words->last_minus = 0;
1048
1049        memset(&xpp, 0, sizeof(xpp));
1050        memset(&xecfg, 0, sizeof(xecfg));
1051        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1052        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1053        xpp.flags = 0;
1054        /* as only the hunk header will be parsed, we need a 0-context */
1055        xecfg.ctxlen = 0;
1056        if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1057                          &xpp, &xecfg))
1058                die("unable to generate word diff");
1059        free(minus.ptr);
1060        free(plus.ptr);
1061        if (diff_words->current_plus != diff_words->plus.text.ptr +
1062                        diff_words->plus.text.size) {
1063                if (color_words_output_graph_prefix(diff_words))
1064                        fputs(line_prefix, diff_words->opt->file);
1065                fn_out_diff_words_write_helper(diff_words->opt->file,
1066                        &style->ctx, style->newline,
1067                        diff_words->plus.text.ptr + diff_words->plus.text.size
1068                        - diff_words->current_plus, diff_words->current_plus,
1069                        line_prefix);
1070        }
1071        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1072}
1073
1074/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1075static void diff_words_flush(struct emit_callback *ecbdata)
1076{
1077        if (ecbdata->diff_words->minus.text.size ||
1078            ecbdata->diff_words->plus.text.size)
1079                diff_words_show(ecbdata->diff_words);
1080}
1081
1082static void diff_filespec_load_driver(struct diff_filespec *one)
1083{
1084        /* Use already-loaded driver */
1085        if (one->driver)
1086                return;
1087
1088        if (S_ISREG(one->mode))
1089                one->driver = userdiff_find_by_path(one->path);
1090
1091        /* Fallback to default settings */
1092        if (!one->driver)
1093                one->driver = userdiff_find_by_name("default");
1094}
1095
1096static const char *userdiff_word_regex(struct diff_filespec *one)
1097{
1098        diff_filespec_load_driver(one);
1099        return one->driver->word_regex;
1100}
1101
1102static void init_diff_words_data(struct emit_callback *ecbdata,
1103                                 struct diff_options *orig_opts,
1104                                 struct diff_filespec *one,
1105                                 struct diff_filespec *two)
1106{
1107        int i;
1108        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1109        memcpy(o, orig_opts, sizeof(struct diff_options));
1110
1111        ecbdata->diff_words =
1112                xcalloc(1, sizeof(struct diff_words_data));
1113        ecbdata->diff_words->type = o->word_diff;
1114        ecbdata->diff_words->opt = o;
1115        if (!o->word_regex)
1116                o->word_regex = userdiff_word_regex(one);
1117        if (!o->word_regex)
1118                o->word_regex = userdiff_word_regex(two);
1119        if (!o->word_regex)
1120                o->word_regex = diff_word_regex_cfg;
1121        if (o->word_regex) {
1122                ecbdata->diff_words->word_regex = (regex_t *)
1123                        xmalloc(sizeof(regex_t));
1124                if (regcomp(ecbdata->diff_words->word_regex,
1125                            o->word_regex,
1126                            REG_EXTENDED | REG_NEWLINE))
1127                        die ("Invalid regular expression: %s",
1128                             o->word_regex);
1129        }
1130        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1131                if (o->word_diff == diff_words_styles[i].type) {
1132                        ecbdata->diff_words->style =
1133                                &diff_words_styles[i];
1134                        break;
1135                }
1136        }
1137        if (want_color(o->use_color)) {
1138                struct diff_words_style *st = ecbdata->diff_words->style;
1139                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1140                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1141                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1142        }
1143}
1144
1145static void free_diff_words_data(struct emit_callback *ecbdata)
1146{
1147        if (ecbdata->diff_words) {
1148                diff_words_flush(ecbdata);
1149                free (ecbdata->diff_words->opt);
1150                free (ecbdata->diff_words->minus.text.ptr);
1151                free (ecbdata->diff_words->minus.orig);
1152                free (ecbdata->diff_words->plus.text.ptr);
1153                free (ecbdata->diff_words->plus.orig);
1154                if (ecbdata->diff_words->word_regex) {
1155                        regfree(ecbdata->diff_words->word_regex);
1156                        free(ecbdata->diff_words->word_regex);
1157                }
1158                free(ecbdata->diff_words);
1159                ecbdata->diff_words = NULL;
1160        }
1161}
1162
1163const char *diff_get_color(int diff_use_color, enum color_diff ix)
1164{
1165        if (want_color(diff_use_color))
1166                return diff_colors[ix];
1167        return "";
1168}
1169
1170const char *diff_line_prefix(struct diff_options *opt)
1171{
1172        struct strbuf *msgbuf;
1173        if (!opt->output_prefix)
1174                return "";
1175
1176        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1177        return msgbuf->buf;
1178}
1179
1180static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1181{
1182        const char *cp;
1183        unsigned long allot;
1184        size_t l = len;
1185
1186        if (ecb->truncate)
1187                return ecb->truncate(line, len);
1188        cp = line;
1189        allot = l;
1190        while (0 < l) {
1191                (void) utf8_width(&cp, &l);
1192                if (!cp)
1193                        break; /* truncated in the middle? */
1194        }
1195        return allot - l;
1196}
1197
1198static void find_lno(const char *line, struct emit_callback *ecbdata)
1199{
1200        const char *p;
1201        ecbdata->lno_in_preimage = 0;
1202        ecbdata->lno_in_postimage = 0;
1203        p = strchr(line, '-');
1204        if (!p)
1205                return; /* cannot happen */
1206        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1207        p = strchr(p, '+');
1208        if (!p)
1209                return; /* cannot happen */
1210        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1211}
1212
1213static void fn_out_consume(void *priv, char *line, unsigned long len)
1214{
1215        struct emit_callback *ecbdata = priv;
1216        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1217        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1218        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1219        struct diff_options *o = ecbdata->opt;
1220        const char *line_prefix = diff_line_prefix(o);
1221
1222        if (ecbdata->header) {
1223                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1224                strbuf_reset(ecbdata->header);
1225                ecbdata->header = NULL;
1226        }
1227        *(ecbdata->found_changesp) = 1;
1228
1229        if (ecbdata->label_path[0]) {
1230                const char *name_a_tab, *name_b_tab;
1231
1232                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1233                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1234
1235                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1236                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1237                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1238                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1239                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1240        }
1241
1242        if (diff_suppress_blank_empty
1243            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1244                line[0] = '\n';
1245                len = 1;
1246        }
1247
1248        if (line[0] == '@') {
1249                if (ecbdata->diff_words)
1250                        diff_words_flush(ecbdata);
1251                len = sane_truncate_line(ecbdata, line, len);
1252                find_lno(line, ecbdata);
1253                emit_hunk_header(ecbdata, line, len);
1254                if (line[len-1] != '\n')
1255                        putc('\n', ecbdata->opt->file);
1256                return;
1257        }
1258
1259        if (len < 1) {
1260                emit_line(ecbdata->opt, reset, reset, line, len);
1261                if (ecbdata->diff_words
1262                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1263                        fputs("~\n", ecbdata->opt->file);
1264                return;
1265        }
1266
1267        if (ecbdata->diff_words) {
1268                if (line[0] == '-') {
1269                        diff_words_append(line, len,
1270                                          &ecbdata->diff_words->minus);
1271                        return;
1272                } else if (line[0] == '+') {
1273                        diff_words_append(line, len,
1274                                          &ecbdata->diff_words->plus);
1275                        return;
1276                } else if (starts_with(line, "\\ ")) {
1277                        /*
1278                         * Eat the "no newline at eof" marker as if we
1279                         * saw a "+" or "-" line with nothing on it,
1280                         * and return without diff_words_flush() to
1281                         * defer processing. If this is the end of
1282                         * preimage, more "+" lines may come after it.
1283                         */
1284                        return;
1285                }
1286                diff_words_flush(ecbdata);
1287                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1288                        emit_line(ecbdata->opt, context, reset, line, len);
1289                        fputs("~\n", ecbdata->opt->file);
1290                } else {
1291                        /*
1292                         * Skip the prefix character, if any.  With
1293                         * diff_suppress_blank_empty, there may be
1294                         * none.
1295                         */
1296                        if (line[0] != '\n') {
1297                              line++;
1298                              len--;
1299                        }
1300                        emit_line(ecbdata->opt, context, reset, line, len);
1301                }
1302                return;
1303        }
1304
1305        switch (line[0]) {
1306        case '+':
1307                ecbdata->lno_in_postimage++;
1308                emit_add_line(reset, ecbdata, line + 1, len - 1);
1309                break;
1310        case '-':
1311                ecbdata->lno_in_preimage++;
1312                emit_del_line(reset, ecbdata, line + 1, len - 1);
1313                break;
1314        case ' ':
1315                ecbdata->lno_in_postimage++;
1316                ecbdata->lno_in_preimage++;
1317                emit_context_line(reset, ecbdata, line + 1, len - 1);
1318                break;
1319        default:
1320                /* incomplete line at the end */
1321                ecbdata->lno_in_preimage++;
1322                emit_line(ecbdata->opt,
1323                          diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
1324                          reset, line, len);
1325                break;
1326        }
1327}
1328
1329static char *pprint_rename(const char *a, const char *b)
1330{
1331        const char *old = a;
1332        const char *new = b;
1333        struct strbuf name = STRBUF_INIT;
1334        int pfx_length, sfx_length;
1335        int pfx_adjust_for_slash;
1336        int len_a = strlen(a);
1337        int len_b = strlen(b);
1338        int a_midlen, b_midlen;
1339        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1340        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1341
1342        if (qlen_a || qlen_b) {
1343                quote_c_style(a, &name, NULL, 0);
1344                strbuf_addstr(&name, " => ");
1345                quote_c_style(b, &name, NULL, 0);
1346                return strbuf_detach(&name, NULL);
1347        }
1348
1349        /* Find common prefix */
1350        pfx_length = 0;
1351        while (*old && *new && *old == *new) {
1352                if (*old == '/')
1353                        pfx_length = old - a + 1;
1354                old++;
1355                new++;
1356        }
1357
1358        /* Find common suffix */
1359        old = a + len_a;
1360        new = b + len_b;
1361        sfx_length = 0;
1362        /*
1363         * If there is a common prefix, it must end in a slash.  In
1364         * that case we let this loop run 1 into the prefix to see the
1365         * same slash.
1366         *
1367         * If there is no common prefix, we cannot do this as it would
1368         * underrun the input strings.
1369         */
1370        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1371        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1372               b + pfx_length - pfx_adjust_for_slash <= new &&
1373               *old == *new) {
1374                if (*old == '/')
1375                        sfx_length = len_a - (old - a);
1376                old--;
1377                new--;
1378        }
1379
1380        /*
1381         * pfx{mid-a => mid-b}sfx
1382         * {pfx-a => pfx-b}sfx
1383         * pfx{sfx-a => sfx-b}
1384         * name-a => name-b
1385         */
1386        a_midlen = len_a - pfx_length - sfx_length;
1387        b_midlen = len_b - pfx_length - sfx_length;
1388        if (a_midlen < 0)
1389                a_midlen = 0;
1390        if (b_midlen < 0)
1391                b_midlen = 0;
1392
1393        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1394        if (pfx_length + sfx_length) {
1395                strbuf_add(&name, a, pfx_length);
1396                strbuf_addch(&name, '{');
1397        }
1398        strbuf_add(&name, a + pfx_length, a_midlen);
1399        strbuf_addstr(&name, " => ");
1400        strbuf_add(&name, b + pfx_length, b_midlen);
1401        if (pfx_length + sfx_length) {
1402                strbuf_addch(&name, '}');
1403                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1404        }
1405        return strbuf_detach(&name, NULL);
1406}
1407
1408struct diffstat_t {
1409        int nr;
1410        int alloc;
1411        struct diffstat_file {
1412                char *from_name;
1413                char *name;
1414                char *print_name;
1415                unsigned is_unmerged:1;
1416                unsigned is_binary:1;
1417                unsigned is_renamed:1;
1418                unsigned is_interesting:1;
1419                uintmax_t added, deleted;
1420        } **files;
1421};
1422
1423static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1424                                          const char *name_a,
1425                                          const char *name_b)
1426{
1427        struct diffstat_file *x;
1428        x = xcalloc(1, sizeof(*x));
1429        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1430        diffstat->files[diffstat->nr++] = x;
1431        if (name_b) {
1432                x->from_name = xstrdup(name_a);
1433                x->name = xstrdup(name_b);
1434                x->is_renamed = 1;
1435        }
1436        else {
1437                x->from_name = NULL;
1438                x->name = xstrdup(name_a);
1439        }
1440        return x;
1441}
1442
1443static void diffstat_consume(void *priv, char *line, unsigned long len)
1444{
1445        struct diffstat_t *diffstat = priv;
1446        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1447
1448        if (line[0] == '+')
1449                x->added++;
1450        else if (line[0] == '-')
1451                x->deleted++;
1452}
1453
1454const char mime_boundary_leader[] = "------------";
1455
1456static int scale_linear(int it, int width, int max_change)
1457{
1458        if (!it)
1459                return 0;
1460        /*
1461         * make sure that at least one '-' or '+' is printed if
1462         * there is any change to this path. The easiest way is to
1463         * scale linearly as if the alloted width is one column shorter
1464         * than it is, and then add 1 to the result.
1465         */
1466        return 1 + (it * (width - 1) / max_change);
1467}
1468
1469static void show_name(FILE *file,
1470                      const char *prefix, const char *name, int len)
1471{
1472        fprintf(file, " %s%-*s |", prefix, len, name);
1473}
1474
1475static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1476{
1477        if (cnt <= 0)
1478                return;
1479        fprintf(file, "%s", set);
1480        while (cnt--)
1481                putc(ch, file);
1482        fprintf(file, "%s", reset);
1483}
1484
1485static void fill_print_name(struct diffstat_file *file)
1486{
1487        char *pname;
1488
1489        if (file->print_name)
1490                return;
1491
1492        if (!file->is_renamed) {
1493                struct strbuf buf = STRBUF_INIT;
1494                if (quote_c_style(file->name, &buf, NULL, 0)) {
1495                        pname = strbuf_detach(&buf, NULL);
1496                } else {
1497                        pname = file->name;
1498                        strbuf_release(&buf);
1499                }
1500        } else {
1501                pname = pprint_rename(file->from_name, file->name);
1502        }
1503        file->print_name = pname;
1504}
1505
1506int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1507{
1508        struct strbuf sb = STRBUF_INIT;
1509        int ret;
1510
1511        if (!files) {
1512                assert(insertions == 0 && deletions == 0);
1513                return fprintf(fp, "%s\n", " 0 files changed");
1514        }
1515
1516        strbuf_addf(&sb,
1517                    (files == 1) ? " %d file changed" : " %d files changed",
1518                    files);
1519
1520        /*
1521         * For binary diff, the caller may want to print "x files
1522         * changed" with insertions == 0 && deletions == 0.
1523         *
1524         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1525         * is probably less confusing (i.e skip over "2 files changed
1526         * but nothing about added/removed lines? Is this a bug in Git?").
1527         */
1528        if (insertions || deletions == 0) {
1529                strbuf_addf(&sb,
1530                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1531                            insertions);
1532        }
1533
1534        if (deletions || insertions == 0) {
1535                strbuf_addf(&sb,
1536                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1537                            deletions);
1538        }
1539        strbuf_addch(&sb, '\n');
1540        ret = fputs(sb.buf, fp);
1541        strbuf_release(&sb);
1542        return ret;
1543}
1544
1545static void show_stats(struct diffstat_t *data, struct diff_options *options)
1546{
1547        int i, len, add, del, adds = 0, dels = 0;
1548        uintmax_t max_change = 0, max_len = 0;
1549        int total_files = data->nr, count;
1550        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1551        const char *reset, *add_c, *del_c;
1552        const char *line_prefix = "";
1553        int extra_shown = 0;
1554
1555        if (data->nr == 0)
1556                return;
1557
1558        line_prefix = diff_line_prefix(options);
1559        count = options->stat_count ? options->stat_count : data->nr;
1560
1561        reset = diff_get_color_opt(options, DIFF_RESET);
1562        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1563        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1564
1565        /*
1566         * Find the longest filename and max number of changes
1567         */
1568        for (i = 0; (i < count) && (i < data->nr); i++) {
1569                struct diffstat_file *file = data->files[i];
1570                uintmax_t change = file->added + file->deleted;
1571
1572                if (!file->is_interesting && (change == 0)) {
1573                        count++; /* not shown == room for one more */
1574                        continue;
1575                }
1576                fill_print_name(file);
1577                len = strlen(file->print_name);
1578                if (max_len < len)
1579                        max_len = len;
1580
1581                if (file->is_unmerged) {
1582                        /* "Unmerged" is 8 characters */
1583                        bin_width = bin_width < 8 ? 8 : bin_width;
1584                        continue;
1585                }
1586                if (file->is_binary) {
1587                        /* "Bin XXX -> YYY bytes" */
1588                        int w = 14 + decimal_width(file->added)
1589                                + decimal_width(file->deleted);
1590                        bin_width = bin_width < w ? w : bin_width;
1591                        /* Display change counts aligned with "Bin" */
1592                        number_width = 3;
1593                        continue;
1594                }
1595
1596                if (max_change < change)
1597                        max_change = change;
1598        }
1599        count = i; /* where we can stop scanning in data->files[] */
1600
1601        /*
1602         * We have width = stat_width or term_columns() columns total.
1603         * We want a maximum of min(max_len, stat_name_width) for the name part.
1604         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1605         * We also need 1 for " " and 4 + decimal_width(max_change)
1606         * for " | NNNN " and one the empty column at the end, altogether
1607         * 6 + decimal_width(max_change).
1608         *
1609         * If there's not enough space, we will use the smaller of
1610         * stat_name_width (if set) and 5/8*width for the filename,
1611         * and the rest for constant elements + graph part, but no more
1612         * than stat_graph_width for the graph part.
1613         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1614         * for the standard terminal size).
1615         *
1616         * In other words: stat_width limits the maximum width, and
1617         * stat_name_width fixes the maximum width of the filename,
1618         * and is also used to divide available columns if there
1619         * aren't enough.
1620         *
1621         * Binary files are displayed with "Bin XXX -> YYY bytes"
1622         * instead of the change count and graph. This part is treated
1623         * similarly to the graph part, except that it is not
1624         * "scaled". If total width is too small to accommodate the
1625         * guaranteed minimum width of the filename part and the
1626         * separators and this message, this message will "overflow"
1627         * making the line longer than the maximum width.
1628         */
1629
1630        if (options->stat_width == -1)
1631                width = term_columns() - strlen(line_prefix);
1632        else
1633                width = options->stat_width ? options->stat_width : 80;
1634        number_width = decimal_width(max_change) > number_width ?
1635                decimal_width(max_change) : number_width;
1636
1637        if (options->stat_graph_width == -1)
1638                options->stat_graph_width = diff_stat_graph_width;
1639
1640        /*
1641         * Guarantee 3/8*16==6 for the graph part
1642         * and 5/8*16==10 for the filename part
1643         */
1644        if (width < 16 + 6 + number_width)
1645                width = 16 + 6 + number_width;
1646
1647        /*
1648         * First assign sizes that are wanted, ignoring available width.
1649         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1650         * starting from "XXX" should fit in graph_width.
1651         */
1652        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1653        if (options->stat_graph_width &&
1654            options->stat_graph_width < graph_width)
1655                graph_width = options->stat_graph_width;
1656
1657        name_width = (options->stat_name_width > 0 &&
1658                      options->stat_name_width < max_len) ?
1659                options->stat_name_width : max_len;
1660
1661        /*
1662         * Adjust adjustable widths not to exceed maximum width
1663         */
1664        if (name_width + number_width + 6 + graph_width > width) {
1665                if (graph_width > width * 3/8 - number_width - 6) {
1666                        graph_width = width * 3/8 - number_width - 6;
1667                        if (graph_width < 6)
1668                                graph_width = 6;
1669                }
1670
1671                if (options->stat_graph_width &&
1672                    graph_width > options->stat_graph_width)
1673                        graph_width = options->stat_graph_width;
1674                if (name_width > width - number_width - 6 - graph_width)
1675                        name_width = width - number_width - 6 - graph_width;
1676                else
1677                        graph_width = width - number_width - 6 - name_width;
1678        }
1679
1680        /*
1681         * From here name_width is the width of the name area,
1682         * and graph_width is the width of the graph area.
1683         * max_change is used to scale graph properly.
1684         */
1685        for (i = 0; i < count; i++) {
1686                const char *prefix = "";
1687                struct diffstat_file *file = data->files[i];
1688                char *name = file->print_name;
1689                uintmax_t added = file->added;
1690                uintmax_t deleted = file->deleted;
1691                int name_len;
1692
1693                if (!file->is_interesting && (added + deleted == 0))
1694                        continue;
1695
1696                /*
1697                 * "scale" the filename
1698                 */
1699                len = name_width;
1700                name_len = strlen(name);
1701                if (name_width < name_len) {
1702                        char *slash;
1703                        prefix = "...";
1704                        len -= 3;
1705                        name += name_len - len;
1706                        slash = strchr(name, '/');
1707                        if (slash)
1708                                name = slash;
1709                }
1710
1711                if (file->is_binary) {
1712                        fprintf(options->file, "%s", line_prefix);
1713                        show_name(options->file, prefix, name, len);
1714                        fprintf(options->file, " %*s", number_width, "Bin");
1715                        if (!added && !deleted) {
1716                                putc('\n', options->file);
1717                                continue;
1718                        }
1719                        fprintf(options->file, " %s%"PRIuMAX"%s",
1720                                del_c, deleted, reset);
1721                        fprintf(options->file, " -> ");
1722                        fprintf(options->file, "%s%"PRIuMAX"%s",
1723                                add_c, added, reset);
1724                        fprintf(options->file, " bytes");
1725                        fprintf(options->file, "\n");
1726                        continue;
1727                }
1728                else if (file->is_unmerged) {
1729                        fprintf(options->file, "%s", line_prefix);
1730                        show_name(options->file, prefix, name, len);
1731                        fprintf(options->file, " Unmerged\n");
1732                        continue;
1733                }
1734
1735                /*
1736                 * scale the add/delete
1737                 */
1738                add = added;
1739                del = deleted;
1740
1741                if (graph_width <= max_change) {
1742                        int total = scale_linear(add + del, graph_width, max_change);
1743                        if (total < 2 && add && del)
1744                                /* width >= 2 due to the sanity check */
1745                                total = 2;
1746                        if (add < del) {
1747                                add = scale_linear(add, graph_width, max_change);
1748                                del = total - add;
1749                        } else {
1750                                del = scale_linear(del, graph_width, max_change);
1751                                add = total - del;
1752                        }
1753                }
1754                fprintf(options->file, "%s", line_prefix);
1755                show_name(options->file, prefix, name, len);
1756                fprintf(options->file, " %*"PRIuMAX"%s",
1757                        number_width, added + deleted,
1758                        added + deleted ? " " : "");
1759                show_graph(options->file, '+', add, add_c, reset);
1760                show_graph(options->file, '-', del, del_c, reset);
1761                fprintf(options->file, "\n");
1762        }
1763
1764        for (i = 0; i < data->nr; i++) {
1765                struct diffstat_file *file = data->files[i];
1766                uintmax_t added = file->added;
1767                uintmax_t deleted = file->deleted;
1768
1769                if (file->is_unmerged ||
1770                    (!file->is_interesting && (added + deleted == 0))) {
1771                        total_files--;
1772                        continue;
1773                }
1774
1775                if (!file->is_binary) {
1776                        adds += added;
1777                        dels += deleted;
1778                }
1779                if (i < count)
1780                        continue;
1781                if (!extra_shown)
1782                        fprintf(options->file, "%s ...\n", line_prefix);
1783                extra_shown = 1;
1784        }
1785        fprintf(options->file, "%s", line_prefix);
1786        print_stat_summary(options->file, total_files, adds, dels);
1787}
1788
1789static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1790{
1791        int i, adds = 0, dels = 0, total_files = data->nr;
1792
1793        if (data->nr == 0)
1794                return;
1795
1796        for (i = 0; i < data->nr; i++) {
1797                int added = data->files[i]->added;
1798                int deleted= data->files[i]->deleted;
1799
1800                if (data->files[i]->is_unmerged ||
1801                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1802                        total_files--;
1803                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1804                        adds += added;
1805                        dels += deleted;
1806                }
1807        }
1808        fprintf(options->file, "%s", diff_line_prefix(options));
1809        print_stat_summary(options->file, total_files, adds, dels);
1810}
1811
1812static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1813{
1814        int i;
1815
1816        if (data->nr == 0)
1817                return;
1818
1819        for (i = 0; i < data->nr; i++) {
1820                struct diffstat_file *file = data->files[i];
1821
1822                fprintf(options->file, "%s", diff_line_prefix(options));
1823
1824                if (file->is_binary)
1825                        fprintf(options->file, "-\t-\t");
1826                else
1827                        fprintf(options->file,
1828                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1829                                file->added, file->deleted);
1830                if (options->line_termination) {
1831                        fill_print_name(file);
1832                        if (!file->is_renamed)
1833                                write_name_quoted(file->name, options->file,
1834                                                  options->line_termination);
1835                        else {
1836                                fputs(file->print_name, options->file);
1837                                putc(options->line_termination, options->file);
1838                        }
1839                } else {
1840                        if (file->is_renamed) {
1841                                putc('\0', options->file);
1842                                write_name_quoted(file->from_name, options->file, '\0');
1843                        }
1844                        write_name_quoted(file->name, options->file, '\0');
1845                }
1846        }
1847}
1848
1849struct dirstat_file {
1850        const char *name;
1851        unsigned long changed;
1852};
1853
1854struct dirstat_dir {
1855        struct dirstat_file *files;
1856        int alloc, nr, permille, cumulative;
1857};
1858
1859static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1860                unsigned long changed, const char *base, int baselen)
1861{
1862        unsigned long this_dir = 0;
1863        unsigned int sources = 0;
1864        const char *line_prefix = diff_line_prefix(opt);
1865
1866        while (dir->nr) {
1867                struct dirstat_file *f = dir->files;
1868                int namelen = strlen(f->name);
1869                unsigned long this;
1870                char *slash;
1871
1872                if (namelen < baselen)
1873                        break;
1874                if (memcmp(f->name, base, baselen))
1875                        break;
1876                slash = strchr(f->name + baselen, '/');
1877                if (slash) {
1878                        int newbaselen = slash + 1 - f->name;
1879                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1880                        sources++;
1881                } else {
1882                        this = f->changed;
1883                        dir->files++;
1884                        dir->nr--;
1885                        sources += 2;
1886                }
1887                this_dir += this;
1888        }
1889
1890        /*
1891         * We don't report dirstat's for
1892         *  - the top level
1893         *  - or cases where everything came from a single directory
1894         *    under this directory (sources == 1).
1895         */
1896        if (baselen && sources != 1) {
1897                if (this_dir) {
1898                        int permille = this_dir * 1000 / changed;
1899                        if (permille >= dir->permille) {
1900                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1901                                        permille / 10, permille % 10, baselen, base);
1902                                if (!dir->cumulative)
1903                                        return 0;
1904                        }
1905                }
1906        }
1907        return this_dir;
1908}
1909
1910static int dirstat_compare(const void *_a, const void *_b)
1911{
1912        const struct dirstat_file *a = _a;
1913        const struct dirstat_file *b = _b;
1914        return strcmp(a->name, b->name);
1915}
1916
1917static void show_dirstat(struct diff_options *options)
1918{
1919        int i;
1920        unsigned long changed;
1921        struct dirstat_dir dir;
1922        struct diff_queue_struct *q = &diff_queued_diff;
1923
1924        dir.files = NULL;
1925        dir.alloc = 0;
1926        dir.nr = 0;
1927        dir.permille = options->dirstat_permille;
1928        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1929
1930        changed = 0;
1931        for (i = 0; i < q->nr; i++) {
1932                struct diff_filepair *p = q->queue[i];
1933                const char *name;
1934                unsigned long copied, added, damage;
1935                int content_changed;
1936
1937                name = p->two->path ? p->two->path : p->one->path;
1938
1939                if (p->one->oid_valid && p->two->oid_valid)
1940                        content_changed = oidcmp(&p->one->oid, &p->two->oid);
1941                else
1942                        content_changed = 1;
1943
1944                if (!content_changed) {
1945                        /*
1946                         * The SHA1 has not changed, so pre-/post-content is
1947                         * identical. We can therefore skip looking at the
1948                         * file contents altogether.
1949                         */
1950                        damage = 0;
1951                        goto found_damage;
1952                }
1953
1954                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1955                        /*
1956                         * In --dirstat-by-file mode, we don't really need to
1957                         * look at the actual file contents at all.
1958                         * The fact that the SHA1 changed is enough for us to
1959                         * add this file to the list of results
1960                         * (with each file contributing equal damage).
1961                         */
1962                        damage = 1;
1963                        goto found_damage;
1964                }
1965
1966                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1967                        diff_populate_filespec(p->one, 0);
1968                        diff_populate_filespec(p->two, 0);
1969                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1970                                               &copied, &added);
1971                        diff_free_filespec_data(p->one);
1972                        diff_free_filespec_data(p->two);
1973                } else if (DIFF_FILE_VALID(p->one)) {
1974                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1975                        copied = added = 0;
1976                        diff_free_filespec_data(p->one);
1977                } else if (DIFF_FILE_VALID(p->two)) {
1978                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1979                        copied = 0;
1980                        added = p->two->size;
1981                        diff_free_filespec_data(p->two);
1982                } else
1983                        continue;
1984
1985                /*
1986                 * Original minus copied is the removed material,
1987                 * added is the new material.  They are both damages
1988                 * made to the preimage.
1989                 * If the resulting damage is zero, we know that
1990                 * diffcore_count_changes() considers the two entries to
1991                 * be identical, but since content_changed is true, we
1992                 * know that there must have been _some_ kind of change,
1993                 * so we force all entries to have damage > 0.
1994                 */
1995                damage = (p->one->size - copied) + added;
1996                if (!damage)
1997                        damage = 1;
1998
1999found_damage:
2000                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2001                dir.files[dir.nr].name = name;
2002                dir.files[dir.nr].changed = damage;
2003                changed += damage;
2004                dir.nr++;
2005        }
2006
2007        /* This can happen even with many files, if everything was renames */
2008        if (!changed)
2009                return;
2010
2011        /* Show all directories with more than x% of the changes */
2012        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2013        gather_dirstat(options, &dir, changed, "", 0);
2014}
2015
2016static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2017{
2018        int i;
2019        unsigned long changed;
2020        struct dirstat_dir dir;
2021
2022        if (data->nr == 0)
2023                return;
2024
2025        dir.files = NULL;
2026        dir.alloc = 0;
2027        dir.nr = 0;
2028        dir.permille = options->dirstat_permille;
2029        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2030
2031        changed = 0;
2032        for (i = 0; i < data->nr; i++) {
2033                struct diffstat_file *file = data->files[i];
2034                unsigned long damage = file->added + file->deleted;
2035                if (file->is_binary)
2036                        /*
2037                         * binary files counts bytes, not lines. Must find some
2038                         * way to normalize binary bytes vs. textual lines.
2039                         * The following heuristic assumes that there are 64
2040                         * bytes per "line".
2041                         * This is stupid and ugly, but very cheap...
2042                         */
2043                        damage = (damage + 63) / 64;
2044                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2045                dir.files[dir.nr].name = file->name;
2046                dir.files[dir.nr].changed = damage;
2047                changed += damage;
2048                dir.nr++;
2049        }
2050
2051        /* This can happen even with many files, if everything was renames */
2052        if (!changed)
2053                return;
2054
2055        /* Show all directories with more than x% of the changes */
2056        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2057        gather_dirstat(options, &dir, changed, "", 0);
2058}
2059
2060static void free_diffstat_info(struct diffstat_t *diffstat)
2061{
2062        int i;
2063        for (i = 0; i < diffstat->nr; i++) {
2064                struct diffstat_file *f = diffstat->files[i];
2065                if (f->name != f->print_name)
2066                        free(f->print_name);
2067                free(f->name);
2068                free(f->from_name);
2069                free(f);
2070        }
2071        free(diffstat->files);
2072}
2073
2074struct checkdiff_t {
2075        const char *filename;
2076        int lineno;
2077        int conflict_marker_size;
2078        struct diff_options *o;
2079        unsigned ws_rule;
2080        unsigned status;
2081};
2082
2083static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2084{
2085        char firstchar;
2086        int cnt;
2087
2088        if (len < marker_size + 1)
2089                return 0;
2090        firstchar = line[0];
2091        switch (firstchar) {
2092        case '=': case '>': case '<': case '|':
2093                break;
2094        default:
2095                return 0;
2096        }
2097        for (cnt = 1; cnt < marker_size; cnt++)
2098                if (line[cnt] != firstchar)
2099                        return 0;
2100        /* line[1] thru line[marker_size-1] are same as firstchar */
2101        if (len < marker_size + 1 || !isspace(line[marker_size]))
2102                return 0;
2103        return 1;
2104}
2105
2106static void checkdiff_consume(void *priv, char *line, unsigned long len)
2107{
2108        struct checkdiff_t *data = priv;
2109        int marker_size = data->conflict_marker_size;
2110        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2111        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2112        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2113        char *err;
2114        const char *line_prefix;
2115
2116        assert(data->o);
2117        line_prefix = diff_line_prefix(data->o);
2118
2119        if (line[0] == '+') {
2120                unsigned bad;
2121                data->lineno++;
2122                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2123                        data->status |= 1;
2124                        fprintf(data->o->file,
2125                                "%s%s:%d: leftover conflict marker\n",
2126                                line_prefix, data->filename, data->lineno);
2127                }
2128                bad = ws_check(line + 1, len - 1, data->ws_rule);
2129                if (!bad)
2130                        return;
2131                data->status |= bad;
2132                err = whitespace_error_string(bad);
2133                fprintf(data->o->file, "%s%s:%d: %s.\n",
2134                        line_prefix, data->filename, data->lineno, err);
2135                free(err);
2136                emit_line(data->o, set, reset, line, 1);
2137                ws_check_emit(line + 1, len - 1, data->ws_rule,
2138                              data->o->file, set, reset, ws);
2139        } else if (line[0] == ' ') {
2140                data->lineno++;
2141        } else if (line[0] == '@') {
2142                char *plus = strchr(line, '+');
2143                if (plus)
2144                        data->lineno = strtol(plus, NULL, 10) - 1;
2145                else
2146                        die("invalid diff");
2147        }
2148}
2149
2150static unsigned char *deflate_it(char *data,
2151                                 unsigned long size,
2152                                 unsigned long *result_size)
2153{
2154        int bound;
2155        unsigned char *deflated;
2156        git_zstream stream;
2157
2158        git_deflate_init(&stream, zlib_compression_level);
2159        bound = git_deflate_bound(&stream, size);
2160        deflated = xmalloc(bound);
2161        stream.next_out = deflated;
2162        stream.avail_out = bound;
2163
2164        stream.next_in = (unsigned char *)data;
2165        stream.avail_in = size;
2166        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2167                ; /* nothing */
2168        git_deflate_end(&stream);
2169        *result_size = stream.total_out;
2170        return deflated;
2171}
2172
2173static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2174                                  const char *prefix)
2175{
2176        void *cp;
2177        void *delta;
2178        void *deflated;
2179        void *data;
2180        unsigned long orig_size;
2181        unsigned long delta_size;
2182        unsigned long deflate_size;
2183        unsigned long data_size;
2184
2185        /* We could do deflated delta, or we could do just deflated two,
2186         * whichever is smaller.
2187         */
2188        delta = NULL;
2189        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2190        if (one->size && two->size) {
2191                delta = diff_delta(one->ptr, one->size,
2192                                   two->ptr, two->size,
2193                                   &delta_size, deflate_size);
2194                if (delta) {
2195                        void *to_free = delta;
2196                        orig_size = delta_size;
2197                        delta = deflate_it(delta, delta_size, &delta_size);
2198                        free(to_free);
2199                }
2200        }
2201
2202        if (delta && delta_size < deflate_size) {
2203                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2204                free(deflated);
2205                data = delta;
2206                data_size = delta_size;
2207        }
2208        else {
2209                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2210                free(delta);
2211                data = deflated;
2212                data_size = deflate_size;
2213        }
2214
2215        /* emit data encoded in base85 */
2216        cp = data;
2217        while (data_size) {
2218                int bytes = (52 < data_size) ? 52 : data_size;
2219                char line[70];
2220                data_size -= bytes;
2221                if (bytes <= 26)
2222                        line[0] = bytes + 'A' - 1;
2223                else
2224                        line[0] = bytes - 26 + 'a' - 1;
2225                encode_85(line + 1, cp, bytes);
2226                cp = (char *) cp + bytes;
2227                fprintf(file, "%s", prefix);
2228                fputs(line, file);
2229                fputc('\n', file);
2230        }
2231        fprintf(file, "%s\n", prefix);
2232        free(data);
2233}
2234
2235static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2236                             const char *prefix)
2237{
2238        fprintf(file, "%sGIT binary patch\n", prefix);
2239        emit_binary_diff_body(file, one, two, prefix);
2240        emit_binary_diff_body(file, two, one, prefix);
2241}
2242
2243int diff_filespec_is_binary(struct diff_filespec *one)
2244{
2245        if (one->is_binary == -1) {
2246                diff_filespec_load_driver(one);
2247                if (one->driver->binary != -1)
2248                        one->is_binary = one->driver->binary;
2249                else {
2250                        if (!one->data && DIFF_FILE_VALID(one))
2251                                diff_populate_filespec(one, CHECK_BINARY);
2252                        if (one->is_binary == -1 && one->data)
2253                                one->is_binary = buffer_is_binary(one->data,
2254                                                one->size);
2255                        if (one->is_binary == -1)
2256                                one->is_binary = 0;
2257                }
2258        }
2259        return one->is_binary;
2260}
2261
2262static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2263{
2264        diff_filespec_load_driver(one);
2265        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2266}
2267
2268void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2269{
2270        if (!options->a_prefix)
2271                options->a_prefix = a;
2272        if (!options->b_prefix)
2273                options->b_prefix = b;
2274}
2275
2276struct userdiff_driver *get_textconv(struct diff_filespec *one)
2277{
2278        if (!DIFF_FILE_VALID(one))
2279                return NULL;
2280
2281        diff_filespec_load_driver(one);
2282        return userdiff_get_textconv(one->driver);
2283}
2284
2285static void builtin_diff(const char *name_a,
2286                         const char *name_b,
2287                         struct diff_filespec *one,
2288                         struct diff_filespec *two,
2289                         const char *xfrm_msg,
2290                         int must_show_header,
2291                         struct diff_options *o,
2292                         int complete_rewrite)
2293{
2294        mmfile_t mf1, mf2;
2295        const char *lbl[2];
2296        char *a_one, *b_two;
2297        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2298        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2299        const char *a_prefix, *b_prefix;
2300        struct userdiff_driver *textconv_one = NULL;
2301        struct userdiff_driver *textconv_two = NULL;
2302        struct strbuf header = STRBUF_INIT;
2303        const char *line_prefix = diff_line_prefix(o);
2304
2305        diff_set_mnemonic_prefix(o, "a/", "b/");
2306        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2307                a_prefix = o->b_prefix;
2308                b_prefix = o->a_prefix;
2309        } else {
2310                a_prefix = o->a_prefix;
2311                b_prefix = o->b_prefix;
2312        }
2313
2314        if (o->submodule_format == DIFF_SUBMODULE_LOG &&
2315            (!one->mode || S_ISGITLINK(one->mode)) &&
2316            (!two->mode || S_ISGITLINK(two->mode))) {
2317                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2318                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2319                show_submodule_summary(o->file, one->path ? one->path : two->path,
2320                                line_prefix,
2321                                &one->oid, &two->oid,
2322                                two->dirty_submodule,
2323                                meta, del, add, reset);
2324                return;
2325        } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
2326                   (!one->mode || S_ISGITLINK(one->mode)) &&
2327                   (!two->mode || S_ISGITLINK(two->mode))) {
2328                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2329                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2330                show_submodule_inline_diff(o->file, one->path ? one->path : two->path,
2331                                line_prefix,
2332                                &one->oid, &two->oid,
2333                                two->dirty_submodule,
2334                                meta, del, add, reset, o);
2335                return;
2336        }
2337
2338        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2339                textconv_one = get_textconv(one);
2340                textconv_two = get_textconv(two);
2341        }
2342
2343        /* Never use a non-valid filename anywhere if at all possible */
2344        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2345        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2346
2347        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2348        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2349        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2350        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2351        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2352        if (lbl[0][0] == '/') {
2353                /* /dev/null */
2354                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2355                if (xfrm_msg)
2356                        strbuf_addstr(&header, xfrm_msg);
2357                must_show_header = 1;
2358        }
2359        else if (lbl[1][0] == '/') {
2360                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2361                if (xfrm_msg)
2362                        strbuf_addstr(&header, xfrm_msg);
2363                must_show_header = 1;
2364        }
2365        else {
2366                if (one->mode != two->mode) {
2367                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2368                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2369                        must_show_header = 1;
2370                }
2371                if (xfrm_msg)
2372                        strbuf_addstr(&header, xfrm_msg);
2373
2374                /*
2375                 * we do not run diff between different kind
2376                 * of objects.
2377                 */
2378                if ((one->mode ^ two->mode) & S_IFMT)
2379                        goto free_ab_and_return;
2380                if (complete_rewrite &&
2381                    (textconv_one || !diff_filespec_is_binary(one)) &&
2382                    (textconv_two || !diff_filespec_is_binary(two))) {
2383                        fprintf(o->file, "%s", header.buf);
2384                        strbuf_reset(&header);
2385                        emit_rewrite_diff(name_a, name_b, one, two,
2386                                                textconv_one, textconv_two, o);
2387                        o->found_changes = 1;
2388                        goto free_ab_and_return;
2389                }
2390        }
2391
2392        if (o->irreversible_delete && lbl[1][0] == '/') {
2393                fprintf(o->file, "%s", header.buf);
2394                strbuf_reset(&header);
2395                goto free_ab_and_return;
2396        } else if (!DIFF_OPT_TST(o, TEXT) &&
2397            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2398              (!textconv_two && diff_filespec_is_binary(two)) )) {
2399                if (!one->data && !two->data &&
2400                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2401                    !DIFF_OPT_TST(o, BINARY)) {
2402                        if (!oidcmp(&one->oid, &two->oid)) {
2403                                if (must_show_header)
2404                                        fprintf(o->file, "%s", header.buf);
2405                                goto free_ab_and_return;
2406                        }
2407                        fprintf(o->file, "%s", header.buf);
2408                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2409                                line_prefix, lbl[0], lbl[1]);
2410                        goto free_ab_and_return;
2411                }
2412                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2413                        die("unable to read files to diff");
2414                /* Quite common confusing case */
2415                if (mf1.size == mf2.size &&
2416                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2417                        if (must_show_header)
2418                                fprintf(o->file, "%s", header.buf);
2419                        goto free_ab_and_return;
2420                }
2421                fprintf(o->file, "%s", header.buf);
2422                strbuf_reset(&header);
2423                if (DIFF_OPT_TST(o, BINARY))
2424                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2425                else
2426                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2427                                line_prefix, lbl[0], lbl[1]);
2428                o->found_changes = 1;
2429        } else {
2430                /* Crazy xdl interfaces.. */
2431                const char *diffopts = getenv("GIT_DIFF_OPTS");
2432                const char *v;
2433                xpparam_t xpp;
2434                xdemitconf_t xecfg;
2435                struct emit_callback ecbdata;
2436                const struct userdiff_funcname *pe;
2437
2438                if (must_show_header) {
2439                        fprintf(o->file, "%s", header.buf);
2440                        strbuf_reset(&header);
2441                }
2442
2443                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2444                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2445
2446                pe = diff_funcname_pattern(one);
2447                if (!pe)
2448                        pe = diff_funcname_pattern(two);
2449
2450                memset(&xpp, 0, sizeof(xpp));
2451                memset(&xecfg, 0, sizeof(xecfg));
2452                memset(&ecbdata, 0, sizeof(ecbdata));
2453                ecbdata.label_path = lbl;
2454                ecbdata.color_diff = want_color(o->use_color);
2455                ecbdata.found_changesp = &o->found_changes;
2456                ecbdata.ws_rule = whitespace_rule(name_b);
2457                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2458                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2459                ecbdata.opt = o;
2460                ecbdata.header = header.len ? &header : NULL;
2461                xpp.flags = o->xdl_opts;
2462                xecfg.ctxlen = o->context;
2463                xecfg.interhunkctxlen = o->interhunkcontext;
2464                xecfg.flags = XDL_EMIT_FUNCNAMES;
2465                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2466                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2467                if (pe)
2468                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2469                if (!diffopts)
2470                        ;
2471                else if (skip_prefix(diffopts, "--unified=", &v))
2472                        xecfg.ctxlen = strtoul(v, NULL, 10);
2473                else if (skip_prefix(diffopts, "-u", &v))
2474                        xecfg.ctxlen = strtoul(v, NULL, 10);
2475                if (o->word_diff)
2476                        init_diff_words_data(&ecbdata, o, one, two);
2477                if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2478                                  &xpp, &xecfg))
2479                        die("unable to generate diff for %s", one->path);
2480                if (o->word_diff)
2481                        free_diff_words_data(&ecbdata);
2482                if (textconv_one)
2483                        free(mf1.ptr);
2484                if (textconv_two)
2485                        free(mf2.ptr);
2486                xdiff_clear_find_func(&xecfg);
2487        }
2488
2489 free_ab_and_return:
2490        strbuf_release(&header);
2491        diff_free_filespec_data(one);
2492        diff_free_filespec_data(two);
2493        free(a_one);
2494        free(b_two);
2495        return;
2496}
2497
2498static void builtin_diffstat(const char *name_a, const char *name_b,
2499                             struct diff_filespec *one,
2500                             struct diff_filespec *two,
2501                             struct diffstat_t *diffstat,
2502                             struct diff_options *o,
2503                             struct diff_filepair *p)
2504{
2505        mmfile_t mf1, mf2;
2506        struct diffstat_file *data;
2507        int same_contents;
2508        int complete_rewrite = 0;
2509
2510        if (!DIFF_PAIR_UNMERGED(p)) {
2511                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2512                        complete_rewrite = 1;
2513        }
2514
2515        data = diffstat_add(diffstat, name_a, name_b);
2516        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2517
2518        if (!one || !two) {
2519                data->is_unmerged = 1;
2520                return;
2521        }
2522
2523        same_contents = !oidcmp(&one->oid, &two->oid);
2524
2525        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2526                data->is_binary = 1;
2527                if (same_contents) {
2528                        data->added = 0;
2529                        data->deleted = 0;
2530                } else {
2531                        data->added = diff_filespec_size(two);
2532                        data->deleted = diff_filespec_size(one);
2533                }
2534        }
2535
2536        else if (complete_rewrite) {
2537                diff_populate_filespec(one, 0);
2538                diff_populate_filespec(two, 0);
2539                data->deleted = count_lines(one->data, one->size);
2540                data->added = count_lines(two->data, two->size);
2541        }
2542
2543        else if (!same_contents) {
2544                /* Crazy xdl interfaces.. */
2545                xpparam_t xpp;
2546                xdemitconf_t xecfg;
2547
2548                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2549                        die("unable to read files to diff");
2550
2551                memset(&xpp, 0, sizeof(xpp));
2552                memset(&xecfg, 0, sizeof(xecfg));
2553                xpp.flags = o->xdl_opts;
2554                xecfg.ctxlen = o->context;
2555                xecfg.interhunkctxlen = o->interhunkcontext;
2556                if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2557                                  &xpp, &xecfg))
2558                        die("unable to generate diffstat for %s", one->path);
2559        }
2560
2561        diff_free_filespec_data(one);
2562        diff_free_filespec_data(two);
2563}
2564
2565static void builtin_checkdiff(const char *name_a, const char *name_b,
2566                              const char *attr_path,
2567                              struct diff_filespec *one,
2568                              struct diff_filespec *two,
2569                              struct diff_options *o)
2570{
2571        mmfile_t mf1, mf2;
2572        struct checkdiff_t data;
2573
2574        if (!two)
2575                return;
2576
2577        memset(&data, 0, sizeof(data));
2578        data.filename = name_b ? name_b : name_a;
2579        data.lineno = 0;
2580        data.o = o;
2581        data.ws_rule = whitespace_rule(attr_path);
2582        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2583
2584        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2585                die("unable to read files to diff");
2586
2587        /*
2588         * All the other codepaths check both sides, but not checking
2589         * the "old" side here is deliberate.  We are checking the newly
2590         * introduced changes, and as long as the "new" side is text, we
2591         * can and should check what it introduces.
2592         */
2593        if (diff_filespec_is_binary(two))
2594                goto free_and_return;
2595        else {
2596                /* Crazy xdl interfaces.. */
2597                xpparam_t xpp;
2598                xdemitconf_t xecfg;
2599
2600                memset(&xpp, 0, sizeof(xpp));
2601                memset(&xecfg, 0, sizeof(xecfg));
2602                xecfg.ctxlen = 1; /* at least one context line */
2603                xpp.flags = 0;
2604                if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2605                                  &xpp, &xecfg))
2606                        die("unable to generate checkdiff for %s", one->path);
2607
2608                if (data.ws_rule & WS_BLANK_AT_EOF) {
2609                        struct emit_callback ecbdata;
2610                        int blank_at_eof;
2611
2612                        ecbdata.ws_rule = data.ws_rule;
2613                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2614                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2615
2616                        if (blank_at_eof) {
2617                                static char *err;
2618                                if (!err)
2619                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2620                                fprintf(o->file, "%s:%d: %s.\n",
2621                                        data.filename, blank_at_eof, err);
2622                                data.status = 1; /* report errors */
2623                        }
2624                }
2625        }
2626 free_and_return:
2627        diff_free_filespec_data(one);
2628        diff_free_filespec_data(two);
2629        if (data.status)
2630                DIFF_OPT_SET(o, CHECK_FAILED);
2631}
2632
2633struct diff_filespec *alloc_filespec(const char *path)
2634{
2635        struct diff_filespec *spec;
2636
2637        FLEXPTR_ALLOC_STR(spec, path, path);
2638        spec->count = 1;
2639        spec->is_binary = -1;
2640        return spec;
2641}
2642
2643void free_filespec(struct diff_filespec *spec)
2644{
2645        if (!--spec->count) {
2646                diff_free_filespec_data(spec);
2647                free(spec);
2648        }
2649}
2650
2651void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2652                   int sha1_valid, unsigned short mode)
2653{
2654        if (mode) {
2655                spec->mode = canon_mode(mode);
2656                hashcpy(spec->oid.hash, sha1);
2657                spec->oid_valid = sha1_valid;
2658        }
2659}
2660
2661/*
2662 * Given a name and sha1 pair, if the index tells us the file in
2663 * the work tree has that object contents, return true, so that
2664 * prepare_temp_file() does not have to inflate and extract.
2665 */
2666static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2667{
2668        const struct cache_entry *ce;
2669        struct stat st;
2670        int pos, len;
2671
2672        /*
2673         * We do not read the cache ourselves here, because the
2674         * benchmark with my previous version that always reads cache
2675         * shows that it makes things worse for diff-tree comparing
2676         * two linux-2.6 kernel trees in an already checked out work
2677         * tree.  This is because most diff-tree comparisons deal with
2678         * only a small number of files, while reading the cache is
2679         * expensive for a large project, and its cost outweighs the
2680         * savings we get by not inflating the object to a temporary
2681         * file.  Practically, this code only helps when we are used
2682         * by diff-cache --cached, which does read the cache before
2683         * calling us.
2684         */
2685        if (!active_cache)
2686                return 0;
2687
2688        /* We want to avoid the working directory if our caller
2689         * doesn't need the data in a normal file, this system
2690         * is rather slow with its stat/open/mmap/close syscalls,
2691         * and the object is contained in a pack file.  The pack
2692         * is probably already open and will be faster to obtain
2693         * the data through than the working directory.  Loose
2694         * objects however would tend to be slower as they need
2695         * to be individually opened and inflated.
2696         */
2697        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2698                return 0;
2699
2700        /*
2701         * Similarly, if we'd have to convert the file contents anyway, that
2702         * makes the optimization not worthwhile.
2703         */
2704        if (!want_file && would_convert_to_git(name))
2705                return 0;
2706
2707        len = strlen(name);
2708        pos = cache_name_pos(name, len);
2709        if (pos < 0)
2710                return 0;
2711        ce = active_cache[pos];
2712
2713        /*
2714         * This is not the sha1 we are looking for, or
2715         * unreusable because it is not a regular file.
2716         */
2717        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2718                return 0;
2719
2720        /*
2721         * If ce is marked as "assume unchanged", there is no
2722         * guarantee that work tree matches what we are looking for.
2723         */
2724        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2725                return 0;
2726
2727        /*
2728         * If ce matches the file in the work tree, we can reuse it.
2729         */
2730        if (ce_uptodate(ce) ||
2731            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2732                return 1;
2733
2734        return 0;
2735}
2736
2737static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2738{
2739        struct strbuf buf = STRBUF_INIT;
2740        char *dirty = "";
2741
2742        /* Are we looking at the work tree? */
2743        if (s->dirty_submodule)
2744                dirty = "-dirty";
2745
2746        strbuf_addf(&buf, "Subproject commit %s%s\n",
2747                    oid_to_hex(&s->oid), dirty);
2748        s->size = buf.len;
2749        if (size_only) {
2750                s->data = NULL;
2751                strbuf_release(&buf);
2752        } else {
2753                s->data = strbuf_detach(&buf, NULL);
2754                s->should_free = 1;
2755        }
2756        return 0;
2757}
2758
2759/*
2760 * While doing rename detection and pickaxe operation, we may need to
2761 * grab the data for the blob (or file) for our own in-core comparison.
2762 * diff_filespec has data and size fields for this purpose.
2763 */
2764int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2765{
2766        int size_only = flags & CHECK_SIZE_ONLY;
2767        int err = 0;
2768        /*
2769         * demote FAIL to WARN to allow inspecting the situation
2770         * instead of refusing.
2771         */
2772        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2773                                    ? SAFE_CRLF_WARN
2774                                    : safe_crlf);
2775
2776        if (!DIFF_FILE_VALID(s))
2777                die("internal error: asking to populate invalid file.");
2778        if (S_ISDIR(s->mode))
2779                return -1;
2780
2781        if (s->data)
2782                return 0;
2783
2784        if (size_only && 0 < s->size)
2785                return 0;
2786
2787        if (S_ISGITLINK(s->mode))
2788                return diff_populate_gitlink(s, size_only);
2789
2790        if (!s->oid_valid ||
2791            reuse_worktree_file(s->path, s->oid.hash, 0)) {
2792                struct strbuf buf = STRBUF_INIT;
2793                struct stat st;
2794                int fd;
2795
2796                if (lstat(s->path, &st) < 0) {
2797                        if (errno == ENOENT) {
2798                        err_empty:
2799                                err = -1;
2800                        empty:
2801                                s->data = (char *)"";
2802                                s->size = 0;
2803                                return err;
2804                        }
2805                }
2806                s->size = xsize_t(st.st_size);
2807                if (!s->size)
2808                        goto empty;
2809                if (S_ISLNK(st.st_mode)) {
2810                        struct strbuf sb = STRBUF_INIT;
2811
2812                        if (strbuf_readlink(&sb, s->path, s->size))
2813                                goto err_empty;
2814                        s->size = sb.len;
2815                        s->data = strbuf_detach(&sb, NULL);
2816                        s->should_free = 1;
2817                        return 0;
2818                }
2819                if (size_only)
2820                        return 0;
2821                if ((flags & CHECK_BINARY) &&
2822                    s->size > big_file_threshold && s->is_binary == -1) {
2823                        s->is_binary = 1;
2824                        return 0;
2825                }
2826                fd = open(s->path, O_RDONLY);
2827                if (fd < 0)
2828                        goto err_empty;
2829                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2830                close(fd);
2831                s->should_munmap = 1;
2832
2833                /*
2834                 * Convert from working tree format to canonical git format
2835                 */
2836                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2837                        size_t size = 0;
2838                        munmap(s->data, s->size);
2839                        s->should_munmap = 0;
2840                        s->data = strbuf_detach(&buf, &size);
2841                        s->size = size;
2842                        s->should_free = 1;
2843                }
2844        }
2845        else {
2846                enum object_type type;
2847                if (size_only || (flags & CHECK_BINARY)) {
2848                        type = sha1_object_info(s->oid.hash, &s->size);
2849                        if (type < 0)
2850                                die("unable to read %s",
2851                                    oid_to_hex(&s->oid));
2852                        if (size_only)
2853                                return 0;
2854                        if (s->size > big_file_threshold && s->is_binary == -1) {
2855                                s->is_binary = 1;
2856                                return 0;
2857                        }
2858                }
2859                s->data = read_sha1_file(s->oid.hash, &type, &s->size);
2860                if (!s->data)
2861                        die("unable to read %s", oid_to_hex(&s->oid));
2862                s->should_free = 1;
2863        }
2864        return 0;
2865}
2866
2867void diff_free_filespec_blob(struct diff_filespec *s)
2868{
2869        if (s->should_free)
2870                free(s->data);
2871        else if (s->should_munmap)
2872                munmap(s->data, s->size);
2873
2874        if (s->should_free || s->should_munmap) {
2875                s->should_free = s->should_munmap = 0;
2876                s->data = NULL;
2877        }
2878}
2879
2880void diff_free_filespec_data(struct diff_filespec *s)
2881{
2882        diff_free_filespec_blob(s);
2883        free(s->cnt_data);
2884        s->cnt_data = NULL;
2885}
2886
2887static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2888                           void *blob,
2889                           unsigned long size,
2890                           const struct object_id *oid,
2891                           int mode)
2892{
2893        int fd;
2894        struct strbuf buf = STRBUF_INIT;
2895        struct strbuf template = STRBUF_INIT;
2896        char *path_dup = xstrdup(path);
2897        const char *base = basename(path_dup);
2898
2899        /* Generate "XXXXXX_basename.ext" */
2900        strbuf_addstr(&template, "XXXXXX_");
2901        strbuf_addstr(&template, base);
2902
2903        fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
2904        if (fd < 0)
2905                die_errno("unable to create temp-file");
2906        if (convert_to_working_tree(path,
2907                        (const char *)blob, (size_t)size, &buf)) {
2908                blob = buf.buf;
2909                size = buf.len;
2910        }
2911        if (write_in_full(fd, blob, size) != size)
2912                die_errno("unable to write temp-file");
2913        close_tempfile(&temp->tempfile);
2914        temp->name = get_tempfile_path(&temp->tempfile);
2915        oid_to_hex_r(temp->hex, oid);
2916        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
2917        strbuf_release(&buf);
2918        strbuf_release(&template);
2919        free(path_dup);
2920}
2921
2922static struct diff_tempfile *prepare_temp_file(const char *name,
2923                struct diff_filespec *one)
2924{
2925        struct diff_tempfile *temp = claim_diff_tempfile();
2926
2927        if (!DIFF_FILE_VALID(one)) {
2928        not_a_valid_file:
2929                /* A '-' entry produces this for file-2, and
2930                 * a '+' entry produces this for file-1.
2931                 */
2932                temp->name = "/dev/null";
2933                xsnprintf(temp->hex, sizeof(temp->hex), ".");
2934                xsnprintf(temp->mode, sizeof(temp->mode), ".");
2935                return temp;
2936        }
2937
2938        if (!S_ISGITLINK(one->mode) &&
2939            (!one->oid_valid ||
2940             reuse_worktree_file(name, one->oid.hash, 1))) {
2941                struct stat st;
2942                if (lstat(name, &st) < 0) {
2943                        if (errno == ENOENT)
2944                                goto not_a_valid_file;
2945                        die_errno("stat(%s)", name);
2946                }
2947                if (S_ISLNK(st.st_mode)) {
2948                        struct strbuf sb = STRBUF_INIT;
2949                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2950                                die_errno("readlink(%s)", name);
2951                        prep_temp_blob(name, temp, sb.buf, sb.len,
2952                                       (one->oid_valid ?
2953                                        &one->oid : &null_oid),
2954                                       (one->oid_valid ?
2955                                        one->mode : S_IFLNK));
2956                        strbuf_release(&sb);
2957                }
2958                else {
2959                        /* we can borrow from the file in the work tree */
2960                        temp->name = name;
2961                        if (!one->oid_valid)
2962                                sha1_to_hex_r(temp->hex, null_sha1);
2963                        else
2964                                sha1_to_hex_r(temp->hex, one->oid.hash);
2965                        /* Even though we may sometimes borrow the
2966                         * contents from the work tree, we always want
2967                         * one->mode.  mode is trustworthy even when
2968                         * !(one->sha1_valid), as long as
2969                         * DIFF_FILE_VALID(one).
2970                         */
2971                        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
2972                }
2973                return temp;
2974        }
2975        else {
2976                if (diff_populate_filespec(one, 0))
2977                        die("cannot read data blob for %s", one->path);
2978                prep_temp_blob(name, temp, one->data, one->size,
2979                               &one->oid, one->mode);
2980        }
2981        return temp;
2982}
2983
2984static void add_external_diff_name(struct argv_array *argv,
2985                                   const char *name,
2986                                   struct diff_filespec *df)
2987{
2988        struct diff_tempfile *temp = prepare_temp_file(name, df);
2989        argv_array_push(argv, temp->name);
2990        argv_array_push(argv, temp->hex);
2991        argv_array_push(argv, temp->mode);
2992}
2993
2994/* An external diff command takes:
2995 *
2996 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2997 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2998 *
2999 */
3000static void run_external_diff(const char *pgm,
3001                              const char *name,
3002                              const char *other,
3003                              struct diff_filespec *one,
3004                              struct diff_filespec *two,
3005                              const char *xfrm_msg,
3006                              int complete_rewrite,
3007                              struct diff_options *o)
3008{
3009        struct argv_array argv = ARGV_ARRAY_INIT;
3010        struct argv_array env = ARGV_ARRAY_INIT;
3011        struct diff_queue_struct *q = &diff_queued_diff;
3012
3013        argv_array_push(&argv, pgm);
3014        argv_array_push(&argv, name);
3015
3016        if (one && two) {
3017                add_external_diff_name(&argv, name, one);
3018                if (!other)
3019                        add_external_diff_name(&argv, name, two);
3020                else {
3021                        add_external_diff_name(&argv, other, two);
3022                        argv_array_push(&argv, other);
3023                        argv_array_push(&argv, xfrm_msg);
3024                }
3025        }
3026
3027        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3028        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3029
3030        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3031                die(_("external diff died, stopping at %s"), name);
3032
3033        remove_tempfile();
3034        argv_array_clear(&argv);
3035        argv_array_clear(&env);
3036}
3037
3038static int similarity_index(struct diff_filepair *p)
3039{
3040        return p->score * 100 / MAX_SCORE;
3041}
3042
3043static void fill_metainfo(struct strbuf *msg,
3044                          const char *name,
3045                          const char *other,
3046                          struct diff_filespec *one,
3047                          struct diff_filespec *two,
3048                          struct diff_options *o,
3049                          struct diff_filepair *p,
3050                          int *must_show_header,
3051                          int use_color)
3052{
3053        const char *set = diff_get_color(use_color, DIFF_METAINFO);
3054        const char *reset = diff_get_color(use_color, DIFF_RESET);
3055        const char *line_prefix = diff_line_prefix(o);
3056
3057        *must_show_header = 1;
3058        strbuf_init(msg, PATH_MAX * 2 + 300);
3059        switch (p->status) {
3060        case DIFF_STATUS_COPIED:
3061                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3062                            line_prefix, set, similarity_index(p));
3063                strbuf_addf(msg, "%s\n%s%scopy from ",
3064                            reset,  line_prefix, set);
3065                quote_c_style(name, msg, NULL, 0);
3066                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3067                quote_c_style(other, msg, NULL, 0);
3068                strbuf_addf(msg, "%s\n", reset);
3069                break;
3070        case DIFF_STATUS_RENAMED:
3071                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3072                            line_prefix, set, similarity_index(p));
3073                strbuf_addf(msg, "%s\n%s%srename from ",
3074                            reset, line_prefix, set);
3075                quote_c_style(name, msg, NULL, 0);
3076                strbuf_addf(msg, "%s\n%s%srename to ",
3077                            reset, line_prefix, set);
3078                quote_c_style(other, msg, NULL, 0);
3079                strbuf_addf(msg, "%s\n", reset);
3080                break;
3081        case DIFF_STATUS_MODIFIED:
3082                if (p->score) {
3083                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3084                                    line_prefix,
3085                                    set, similarity_index(p), reset);
3086                        break;
3087                }
3088                /* fallthru */
3089        default:
3090                *must_show_header = 0;
3091        }
3092        if (one && two && oidcmp(&one->oid, &two->oid)) {
3093                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3094
3095                if (DIFF_OPT_TST(o, BINARY)) {
3096                        mmfile_t mf;
3097                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3098                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3099                                abbrev = 40;
3100                }
3101                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3102                            find_unique_abbrev(one->oid.hash, abbrev));
3103                strbuf_addstr(msg, find_unique_abbrev(two->oid.hash, abbrev));
3104                if (one->mode == two->mode)
3105                        strbuf_addf(msg, " %06o", one->mode);
3106                strbuf_addf(msg, "%s\n", reset);
3107        }
3108}
3109
3110static void run_diff_cmd(const char *pgm,
3111                         const char *name,
3112                         const char *other,
3113                         const char *attr_path,
3114                         struct diff_filespec *one,
3115                         struct diff_filespec *two,
3116                         struct strbuf *msg,
3117                         struct diff_options *o,
3118                         struct diff_filepair *p)
3119{
3120        const char *xfrm_msg = NULL;
3121        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3122        int must_show_header = 0;
3123
3124
3125        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3126                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3127                if (drv && drv->external)
3128                        pgm = drv->external;
3129        }
3130
3131        if (msg) {
3132                /*
3133                 * don't use colors when the header is intended for an
3134                 * external diff driver
3135                 */
3136                fill_metainfo(msg, name, other, one, two, o, p,
3137                              &must_show_header,
3138                              want_color(o->use_color) && !pgm);
3139                xfrm_msg = msg->len ? msg->buf : NULL;
3140        }
3141
3142        if (pgm) {
3143                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3144                                  complete_rewrite, o);
3145                return;
3146        }
3147        if (one && two)
3148                builtin_diff(name, other ? other : name,
3149                             one, two, xfrm_msg, must_show_header,
3150                             o, complete_rewrite);
3151        else
3152                fprintf(o->file, "* Unmerged path %s\n", name);
3153}
3154
3155static void diff_fill_sha1_info(struct diff_filespec *one)
3156{
3157        if (DIFF_FILE_VALID(one)) {
3158                if (!one->oid_valid) {
3159                        struct stat st;
3160                        if (one->is_stdin) {
3161                                oidclr(&one->oid);
3162                                return;
3163                        }
3164                        if (lstat(one->path, &st) < 0)
3165                                die_errno("stat '%s'", one->path);
3166                        if (index_path(one->oid.hash, one->path, &st, 0))
3167                                die("cannot hash %s", one->path);
3168                }
3169        }
3170        else
3171                oidclr(&one->oid);
3172}
3173
3174static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3175{
3176        /* Strip the prefix but do not molest /dev/null and absolute paths */
3177        if (*namep && **namep != '/') {
3178                *namep += prefix_length;
3179                if (**namep == '/')
3180                        ++*namep;
3181        }
3182        if (*otherp && **otherp != '/') {
3183                *otherp += prefix_length;
3184                if (**otherp == '/')
3185                        ++*otherp;
3186        }
3187}
3188
3189static void run_diff(struct diff_filepair *p, struct diff_options *o)
3190{
3191        const char *pgm = external_diff();
3192        struct strbuf msg;
3193        struct diff_filespec *one = p->one;
3194        struct diff_filespec *two = p->two;
3195        const char *name;
3196        const char *other;
3197        const char *attr_path;
3198
3199        name  = p->one->path;
3200        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3201        attr_path = name;
3202        if (o->prefix_length)
3203                strip_prefix(o->prefix_length, &name, &other);
3204
3205        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3206                pgm = NULL;
3207
3208        if (DIFF_PAIR_UNMERGED(p)) {
3209                run_diff_cmd(pgm, name, NULL, attr_path,
3210                             NULL, NULL, NULL, o, p);
3211                return;
3212        }
3213
3214        diff_fill_sha1_info(one);
3215        diff_fill_sha1_info(two);
3216
3217        if (!pgm &&
3218            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3219            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3220                /*
3221                 * a filepair that changes between file and symlink
3222                 * needs to be split into deletion and creation.
3223                 */
3224                struct diff_filespec *null = alloc_filespec(two->path);
3225                run_diff_cmd(NULL, name, other, attr_path,
3226                             one, null, &msg, o, p);
3227                free(null);
3228                strbuf_release(&msg);
3229
3230                null = alloc_filespec(one->path);
3231                run_diff_cmd(NULL, name, other, attr_path,
3232                             null, two, &msg, o, p);
3233                free(null);
3234        }
3235        else
3236                run_diff_cmd(pgm, name, other, attr_path,
3237                             one, two, &msg, o, p);
3238
3239        strbuf_release(&msg);
3240}
3241
3242static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3243                         struct diffstat_t *diffstat)
3244{
3245        const char *name;
3246        const char *other;
3247
3248        if (DIFF_PAIR_UNMERGED(p)) {
3249                /* unmerged */
3250                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3251                return;
3252        }
3253
3254        name = p->one->path;
3255        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3256
3257        if (o->prefix_length)
3258                strip_prefix(o->prefix_length, &name, &other);
3259
3260        diff_fill_sha1_info(p->one);
3261        diff_fill_sha1_info(p->two);
3262
3263        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3264}
3265
3266static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3267{
3268        const char *name;
3269        const char *other;
3270        const char *attr_path;
3271
3272        if (DIFF_PAIR_UNMERGED(p)) {
3273                /* unmerged */
3274                return;
3275        }
3276
3277        name = p->one->path;
3278        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3279        attr_path = other ? other : name;
3280
3281        if (o->prefix_length)
3282                strip_prefix(o->prefix_length, &name, &other);
3283
3284        diff_fill_sha1_info(p->one);
3285        diff_fill_sha1_info(p->two);
3286
3287        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3288}
3289
3290void diff_setup(struct diff_options *options)
3291{
3292        memcpy(options, &default_diff_options, sizeof(*options));
3293
3294        options->file = stdout;
3295
3296        options->line_termination = '\n';
3297        options->break_opt = -1;
3298        options->rename_limit = -1;
3299        options->dirstat_permille = diff_dirstat_permille_default;
3300        options->context = diff_context_default;
3301        options->ws_error_highlight = WSEH_NEW;
3302        DIFF_OPT_SET(options, RENAME_EMPTY);
3303
3304        /* pathchange left =NULL by default */
3305        options->change = diff_change;
3306        options->add_remove = diff_addremove;
3307        options->use_color = diff_use_color_default;
3308        options->detect_rename = diff_detect_rename_default;
3309        options->xdl_opts |= diff_algorithm;
3310        if (diff_compaction_heuristic)
3311                DIFF_XDL_SET(options, COMPACTION_HEURISTIC);
3312
3313        options->orderfile = diff_order_file_cfg;
3314
3315        if (diff_no_prefix) {
3316                options->a_prefix = options->b_prefix = "";
3317        } else if (!diff_mnemonic_prefix) {
3318                options->a_prefix = "a/";
3319                options->b_prefix = "b/";
3320        }
3321}
3322
3323void diff_setup_done(struct diff_options *options)
3324{
3325        int count = 0;
3326
3327        if (options->set_default)
3328                options->set_default(options);
3329
3330        if (options->output_format & DIFF_FORMAT_NAME)
3331                count++;
3332        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3333                count++;
3334        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3335                count++;
3336        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3337                count++;
3338        if (count > 1)
3339                die("--name-only, --name-status, --check and -s are mutually exclusive");
3340
3341        /*
3342         * Most of the time we can say "there are changes"
3343         * only by checking if there are changed paths, but
3344         * --ignore-whitespace* options force us to look
3345         * inside contents.
3346         */
3347
3348        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3349            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3350            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3351                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3352        else
3353                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3354
3355        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3356                options->detect_rename = DIFF_DETECT_COPY;
3357
3358        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3359                options->prefix = NULL;
3360        if (options->prefix)
3361                options->prefix_length = strlen(options->prefix);
3362        else
3363                options->prefix_length = 0;
3364
3365        if (options->output_format & (DIFF_FORMAT_NAME |
3366                                      DIFF_FORMAT_NAME_STATUS |
3367                                      DIFF_FORMAT_CHECKDIFF |
3368                                      DIFF_FORMAT_NO_OUTPUT))
3369                options->output_format &= ~(DIFF_FORMAT_RAW |
3370                                            DIFF_FORMAT_NUMSTAT |
3371                                            DIFF_FORMAT_DIFFSTAT |
3372                                            DIFF_FORMAT_SHORTSTAT |
3373                                            DIFF_FORMAT_DIRSTAT |
3374                                            DIFF_FORMAT_SUMMARY |
3375                                            DIFF_FORMAT_PATCH);
3376
3377        /*
3378         * These cases always need recursive; we do not drop caller-supplied
3379         * recursive bits for other formats here.
3380         */
3381        if (options->output_format & (DIFF_FORMAT_PATCH |
3382                                      DIFF_FORMAT_NUMSTAT |
3383                                      DIFF_FORMAT_DIFFSTAT |
3384                                      DIFF_FORMAT_SHORTSTAT |
3385                                      DIFF_FORMAT_DIRSTAT |
3386                                      DIFF_FORMAT_SUMMARY |
3387                                      DIFF_FORMAT_CHECKDIFF))
3388                DIFF_OPT_SET(options, RECURSIVE);
3389        /*
3390         * Also pickaxe would not work very well if you do not say recursive
3391         */
3392        if (options->pickaxe)
3393                DIFF_OPT_SET(options, RECURSIVE);
3394        /*
3395         * When patches are generated, submodules diffed against the work tree
3396         * must be checked for dirtiness too so it can be shown in the output
3397         */
3398        if (options->output_format & DIFF_FORMAT_PATCH)
3399                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3400
3401        if (options->detect_rename && options->rename_limit < 0)
3402                options->rename_limit = diff_rename_limit_default;
3403        if (options->setup & DIFF_SETUP_USE_CACHE) {
3404                if (!active_cache)
3405                        /* read-cache does not die even when it fails
3406                         * so it is safe for us to do this here.  Also
3407                         * it does not smudge active_cache or active_nr
3408                         * when it fails, so we do not have to worry about
3409                         * cleaning it up ourselves either.
3410                         */
3411                        read_cache();
3412        }
3413        if (options->abbrev <= 0 || 40 < options->abbrev)
3414                options->abbrev = 40; /* full */
3415
3416        /*
3417         * It does not make sense to show the first hit we happened
3418         * to have found.  It does not make sense not to return with
3419         * exit code in such a case either.
3420         */
3421        if (DIFF_OPT_TST(options, QUICK)) {
3422                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3423                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3424        }
3425
3426        options->diff_path_counter = 0;
3427
3428        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3429                die(_("--follow requires exactly one pathspec"));
3430}
3431
3432static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3433{
3434        char c, *eq;
3435        int len;
3436
3437        if (*arg != '-')
3438                return 0;
3439        c = *++arg;
3440        if (!c)
3441                return 0;
3442        if (c == arg_short) {
3443                c = *++arg;
3444                if (!c)
3445                        return 1;
3446                if (val && isdigit(c)) {
3447                        char *end;
3448                        int n = strtoul(arg, &end, 10);
3449                        if (*end)
3450                                return 0;
3451                        *val = n;
3452                        return 1;
3453                }
3454                return 0;
3455        }
3456        if (c != '-')
3457                return 0;
3458        arg++;
3459        eq = strchrnul(arg, '=');
3460        len = eq - arg;
3461        if (!len || strncmp(arg, arg_long, len))
3462                return 0;
3463        if (*eq) {
3464                int n;
3465                char *end;
3466                if (!isdigit(*++eq))
3467                        return 0;
3468                n = strtoul(eq, &end, 10);
3469                if (*end)
3470                        return 0;
3471                *val = n;
3472        }
3473        return 1;
3474}
3475
3476static int diff_scoreopt_parse(const char *opt);
3477
3478static inline int short_opt(char opt, const char **argv,
3479                            const char **optarg)
3480{
3481        const char *arg = argv[0];
3482        if (arg[0] != '-' || arg[1] != opt)
3483                return 0;
3484        if (arg[2] != '\0') {
3485                *optarg = arg + 2;
3486                return 1;
3487        }
3488        if (!argv[1])
3489                die("Option '%c' requires a value", opt);
3490        *optarg = argv[1];
3491        return 2;
3492}
3493
3494int parse_long_opt(const char *opt, const char **argv,
3495                   const char **optarg)
3496{
3497        const char *arg = argv[0];
3498        if (!skip_prefix(arg, "--", &arg))
3499                return 0;
3500        if (!skip_prefix(arg, opt, &arg))
3501                return 0;
3502        if (*arg == '=') { /* stuck form: --option=value */
3503                *optarg = arg + 1;
3504                return 1;
3505        }
3506        if (*arg != '\0')
3507                return 0;
3508        /* separate form: --option value */
3509        if (!argv[1])
3510                die("Option '--%s' requires a value", opt);
3511        *optarg = argv[1];
3512        return 2;
3513}
3514
3515static int stat_opt(struct diff_options *options, const char **av)
3516{
3517        const char *arg = av[0];
3518        char *end;
3519        int width = options->stat_width;
3520        int name_width = options->stat_name_width;
3521        int graph_width = options->stat_graph_width;
3522        int count = options->stat_count;
3523        int argcount = 1;
3524
3525        if (!skip_prefix(arg, "--stat", &arg))
3526                die("BUG: stat option does not begin with --stat: %s", arg);
3527        end = (char *)arg;
3528
3529        switch (*arg) {
3530        case '-':
3531                if (skip_prefix(arg, "-width", &arg)) {
3532                        if (*arg == '=')
3533                                width = strtoul(arg + 1, &end, 10);
3534                        else if (!*arg && !av[1])
3535                                die("Option '--stat-width' requires a value");
3536                        else if (!*arg) {
3537                                width = strtoul(av[1], &end, 10);
3538                                argcount = 2;
3539                        }
3540                } else if (skip_prefix(arg, "-name-width", &arg)) {
3541                        if (*arg == '=')
3542                                name_width = strtoul(arg + 1, &end, 10);
3543                        else if (!*arg && !av[1])
3544                                die("Option '--stat-name-width' requires a value");
3545                        else if (!*arg) {
3546                                name_width = strtoul(av[1], &end, 10);
3547                                argcount = 2;
3548                        }
3549                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3550                        if (*arg == '=')
3551                                graph_width = strtoul(arg + 1, &end, 10);
3552                        else if (!*arg && !av[1])
3553                                die("Option '--stat-graph-width' requires a value");
3554                        else if (!*arg) {
3555                                graph_width = strtoul(av[1], &end, 10);
3556                                argcount = 2;
3557                        }
3558                } else if (skip_prefix(arg, "-count", &arg)) {
3559                        if (*arg == '=')
3560                                count = strtoul(arg + 1, &end, 10);
3561                        else if (!*arg && !av[1])
3562                                die("Option '--stat-count' requires a value");
3563                        else if (!*arg) {
3564                                count = strtoul(av[1], &end, 10);
3565                                argcount = 2;
3566                        }
3567                }
3568                break;
3569        case '=':
3570                width = strtoul(arg+1, &end, 10);
3571                if (*end == ',')
3572                        name_width = strtoul(end+1, &end, 10);
3573                if (*end == ',')
3574                        count = strtoul(end+1, &end, 10);
3575        }
3576
3577        /* Important! This checks all the error cases! */
3578        if (*end)
3579                return 0;
3580        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3581        options->stat_name_width = name_width;
3582        options->stat_graph_width = graph_width;
3583        options->stat_width = width;
3584        options->stat_count = count;
3585        return argcount;
3586}
3587
3588static int parse_dirstat_opt(struct diff_options *options, const char *params)
3589{
3590        struct strbuf errmsg = STRBUF_INIT;
3591        if (parse_dirstat_params(options, params, &errmsg))
3592                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3593                    errmsg.buf);
3594        strbuf_release(&errmsg);
3595        /*
3596         * The caller knows a dirstat-related option is given from the command
3597         * line; allow it to say "return this_function();"
3598         */
3599        options->output_format |= DIFF_FORMAT_DIRSTAT;
3600        return 1;
3601}
3602
3603static int parse_submodule_opt(struct diff_options *options, const char *value)
3604{
3605        if (parse_submodule_params(options, value))
3606                die(_("Failed to parse --submodule option parameter: '%s'"),
3607                        value);
3608        return 1;
3609}
3610
3611static const char diff_status_letters[] = {
3612        DIFF_STATUS_ADDED,
3613        DIFF_STATUS_COPIED,
3614        DIFF_STATUS_DELETED,
3615        DIFF_STATUS_MODIFIED,
3616        DIFF_STATUS_RENAMED,
3617        DIFF_STATUS_TYPE_CHANGED,
3618        DIFF_STATUS_UNKNOWN,
3619        DIFF_STATUS_UNMERGED,
3620        DIFF_STATUS_FILTER_AON,
3621        DIFF_STATUS_FILTER_BROKEN,
3622        '\0',
3623};
3624
3625static unsigned int filter_bit['Z' + 1];
3626
3627static void prepare_filter_bits(void)
3628{
3629        int i;
3630
3631        if (!filter_bit[DIFF_STATUS_ADDED]) {
3632                for (i = 0; diff_status_letters[i]; i++)
3633                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3634        }
3635}
3636
3637static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3638{
3639        return opt->filter & filter_bit[(int) status];
3640}
3641
3642static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3643{
3644        int i, optch;
3645
3646        prepare_filter_bits();
3647
3648        /*
3649         * If there is a negation e.g. 'd' in the input, and we haven't
3650         * initialized the filter field with another --diff-filter, start
3651         * from full set of bits, except for AON.
3652         */
3653        if (!opt->filter) {
3654                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3655                        if (optch < 'a' || 'z' < optch)
3656                                continue;
3657                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3658                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3659                        break;
3660                }
3661        }
3662
3663        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3664                unsigned int bit;
3665                int negate;
3666
3667                if ('a' <= optch && optch <= 'z') {
3668                        negate = 1;
3669                        optch = toupper(optch);
3670                } else {
3671                        negate = 0;
3672                }
3673
3674                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3675                if (!bit)
3676                        return optarg[i];
3677                if (negate)
3678                        opt->filter &= ~bit;
3679                else
3680                        opt->filter |= bit;
3681        }
3682        return 0;
3683}
3684
3685static void enable_patch_output(int *fmt) {
3686        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3687        *fmt |= DIFF_FORMAT_PATCH;
3688}
3689
3690static int parse_one_token(const char **arg, const char *token)
3691{
3692        const char *rest;
3693        if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
3694                *arg = rest;
3695                return 1;
3696        }
3697        return 0;
3698}
3699
3700static int parse_ws_error_highlight(struct diff_options *opt, const char *arg)
3701{
3702        const char *orig_arg = arg;
3703        unsigned val = 0;
3704        while (*arg) {
3705                if (parse_one_token(&arg, "none"))
3706                        val = 0;
3707                else if (parse_one_token(&arg, "default"))
3708                        val = WSEH_NEW;
3709                else if (parse_one_token(&arg, "all"))
3710                        val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
3711                else if (parse_one_token(&arg, "new"))
3712                        val |= WSEH_NEW;
3713                else if (parse_one_token(&arg, "old"))
3714                        val |= WSEH_OLD;
3715                else if (parse_one_token(&arg, "context"))
3716                        val |= WSEH_CONTEXT;
3717                else {
3718                        error("unknown value after ws-error-highlight=%.*s",
3719                              (int)(arg - orig_arg), orig_arg);
3720                        return 0;
3721                }
3722                if (*arg)
3723                        arg++;
3724        }
3725        opt->ws_error_highlight = val;
3726        return 1;
3727}
3728
3729int diff_opt_parse(struct diff_options *options,
3730                   const char **av, int ac, const char *prefix)
3731{
3732        const char *arg = av[0];
3733        const char *optarg;
3734        int argcount;
3735
3736        if (!prefix)
3737                prefix = "";
3738
3739        /* Output format options */
3740        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3741            || opt_arg(arg, 'U', "unified", &options->context))
3742                enable_patch_output(&options->output_format);
3743        else if (!strcmp(arg, "--raw"))
3744                options->output_format |= DIFF_FORMAT_RAW;
3745        else if (!strcmp(arg, "--patch-with-raw")) {
3746                enable_patch_output(&options->output_format);
3747                options->output_format |= DIFF_FORMAT_RAW;
3748        } else if (!strcmp(arg, "--numstat"))
3749                options->output_format |= DIFF_FORMAT_NUMSTAT;
3750        else if (!strcmp(arg, "--shortstat"))
3751                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3752        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3753                return parse_dirstat_opt(options, "");
3754        else if (skip_prefix(arg, "-X", &arg))
3755                return parse_dirstat_opt(options, arg);
3756        else if (skip_prefix(arg, "--dirstat=", &arg))
3757                return parse_dirstat_opt(options, arg);
3758        else if (!strcmp(arg, "--cumulative"))
3759                return parse_dirstat_opt(options, "cumulative");
3760        else if (!strcmp(arg, "--dirstat-by-file"))
3761                return parse_dirstat_opt(options, "files");
3762        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3763                parse_dirstat_opt(options, "files");
3764                return parse_dirstat_opt(options, arg);
3765        }
3766        else if (!strcmp(arg, "--check"))
3767                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3768        else if (!strcmp(arg, "--summary"))
3769                options->output_format |= DIFF_FORMAT_SUMMARY;
3770        else if (!strcmp(arg, "--patch-with-stat")) {
3771                enable_patch_output(&options->output_format);
3772                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3773        } else if (!strcmp(arg, "--name-only"))
3774                options->output_format |= DIFF_FORMAT_NAME;
3775        else if (!strcmp(arg, "--name-status"))
3776                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3777        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3778                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3779        else if (starts_with(arg, "--stat"))
3780                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3781                return stat_opt(options, av);
3782
3783        /* renames options */
3784        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3785                 !strcmp(arg, "--break-rewrites")) {
3786                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3787                        return error("invalid argument to -B: %s", arg+2);
3788        }
3789        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3790                 !strcmp(arg, "--find-renames")) {
3791                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3792                        return error("invalid argument to -M: %s", arg+2);
3793                options->detect_rename = DIFF_DETECT_RENAME;
3794        }
3795        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3796                options->irreversible_delete = 1;
3797        }
3798        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3799                 !strcmp(arg, "--find-copies")) {
3800                if (options->detect_rename == DIFF_DETECT_COPY)
3801                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3802                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3803                        return error("invalid argument to -C: %s", arg+2);
3804                options->detect_rename = DIFF_DETECT_COPY;
3805        }
3806        else if (!strcmp(arg, "--no-renames"))
3807                options->detect_rename = 0;
3808        else if (!strcmp(arg, "--rename-empty"))
3809                DIFF_OPT_SET(options, RENAME_EMPTY);
3810        else if (!strcmp(arg, "--no-rename-empty"))
3811                DIFF_OPT_CLR(options, RENAME_EMPTY);
3812        else if (!strcmp(arg, "--relative"))
3813                DIFF_OPT_SET(options, RELATIVE_NAME);
3814        else if (skip_prefix(arg, "--relative=", &arg)) {
3815                DIFF_OPT_SET(options, RELATIVE_NAME);
3816                options->prefix = arg;
3817        }
3818
3819        /* xdiff options */
3820        else if (!strcmp(arg, "--minimal"))
3821                DIFF_XDL_SET(options, NEED_MINIMAL);
3822        else if (!strcmp(arg, "--no-minimal"))
3823                DIFF_XDL_CLR(options, NEED_MINIMAL);
3824        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3825                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3826        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3827                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3828        else if (!strcmp(arg, "--ignore-space-at-eol"))
3829                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3830        else if (!strcmp(arg, "--ignore-blank-lines"))
3831                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3832        else if (!strcmp(arg, "--compaction-heuristic"))
3833                DIFF_XDL_SET(options, COMPACTION_HEURISTIC);
3834        else if (!strcmp(arg, "--no-compaction-heuristic"))
3835                DIFF_XDL_CLR(options, COMPACTION_HEURISTIC);
3836        else if (!strcmp(arg, "--patience"))
3837                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3838        else if (!strcmp(arg, "--histogram"))
3839                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3840        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3841                long value = parse_algorithm_value(optarg);
3842                if (value < 0)
3843                        return error("option diff-algorithm accepts \"myers\", "
3844                                     "\"minimal\", \"patience\" and \"histogram\"");
3845                /* clear out previous settings */
3846                DIFF_XDL_CLR(options, NEED_MINIMAL);
3847                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3848                options->xdl_opts |= value;
3849                return argcount;
3850        }
3851
3852        /* flags options */
3853        else if (!strcmp(arg, "--binary")) {
3854                enable_patch_output(&options->output_format);
3855                DIFF_OPT_SET(options, BINARY);
3856        }
3857        else if (!strcmp(arg, "--full-index"))
3858                DIFF_OPT_SET(options, FULL_INDEX);
3859        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3860                DIFF_OPT_SET(options, TEXT);
3861        else if (!strcmp(arg, "-R"))
3862                DIFF_OPT_SET(options, REVERSE_DIFF);
3863        else if (!strcmp(arg, "--find-copies-harder"))
3864                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3865        else if (!strcmp(arg, "--follow"))
3866                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3867        else if (!strcmp(arg, "--no-follow")) {
3868                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3869                DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
3870        } else if (!strcmp(arg, "--color"))
3871                options->use_color = 1;
3872        else if (skip_prefix(arg, "--color=", &arg)) {
3873                int value = git_config_colorbool(NULL, arg);
3874                if (value < 0)
3875                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3876                options->use_color = value;
3877        }
3878        else if (!strcmp(arg, "--no-color"))
3879                options->use_color = 0;
3880        else if (!strcmp(arg, "--color-words")) {
3881                options->use_color = 1;
3882                options->word_diff = DIFF_WORDS_COLOR;
3883        }
3884        else if (skip_prefix(arg, "--color-words=", &arg)) {
3885                options->use_color = 1;
3886                options->word_diff = DIFF_WORDS_COLOR;
3887                options->word_regex = arg;
3888        }
3889        else if (!strcmp(arg, "--word-diff")) {
3890                if (options->word_diff == DIFF_WORDS_NONE)
3891                        options->word_diff = DIFF_WORDS_PLAIN;
3892        }
3893        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3894                if (!strcmp(arg, "plain"))
3895                        options->word_diff = DIFF_WORDS_PLAIN;
3896                else if (!strcmp(arg, "color")) {
3897                        options->use_color = 1;
3898                        options->word_diff = DIFF_WORDS_COLOR;
3899                }
3900                else if (!strcmp(arg, "porcelain"))
3901                        options->word_diff = DIFF_WORDS_PORCELAIN;
3902                else if (!strcmp(arg, "none"))
3903                        options->word_diff = DIFF_WORDS_NONE;
3904                else
3905                        die("bad --word-diff argument: %s", arg);
3906        }
3907        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3908                if (options->word_diff == DIFF_WORDS_NONE)
3909                        options->word_diff = DIFF_WORDS_PLAIN;
3910                options->word_regex = optarg;
3911                return argcount;
3912        }
3913        else if (!strcmp(arg, "--exit-code"))
3914                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3915        else if (!strcmp(arg, "--quiet"))
3916                DIFF_OPT_SET(options, QUICK);
3917        else if (!strcmp(arg, "--ext-diff"))
3918                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3919        else if (!strcmp(arg, "--no-ext-diff"))
3920                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3921        else if (!strcmp(arg, "--textconv"))
3922                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3923        else if (!strcmp(arg, "--no-textconv"))
3924                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3925        else if (!strcmp(arg, "--ignore-submodules")) {
3926                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3927                handle_ignore_submodules_arg(options, "all");
3928        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3929                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3930                handle_ignore_submodules_arg(options, arg);
3931        } else if (!strcmp(arg, "--submodule"))
3932                options->submodule_format = DIFF_SUBMODULE_LOG;
3933        else if (skip_prefix(arg, "--submodule=", &arg))
3934                return parse_submodule_opt(options, arg);
3935        else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
3936                return parse_ws_error_highlight(options, arg);
3937
3938        /* misc options */
3939        else if (!strcmp(arg, "-z"))
3940                options->line_termination = 0;
3941        else if ((argcount = short_opt('l', av, &optarg))) {
3942                options->rename_limit = strtoul(optarg, NULL, 10);
3943                return argcount;
3944        }
3945        else if ((argcount = short_opt('S', av, &optarg))) {
3946                options->pickaxe = optarg;
3947                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3948                return argcount;
3949        } else if ((argcount = short_opt('G', av, &optarg))) {
3950                options->pickaxe = optarg;
3951                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3952                return argcount;
3953        }
3954        else if (!strcmp(arg, "--pickaxe-all"))
3955                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3956        else if (!strcmp(arg, "--pickaxe-regex"))
3957                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3958        else if ((argcount = short_opt('O', av, &optarg))) {
3959                const char *path = prefix_filename(prefix, strlen(prefix), optarg);
3960                options->orderfile = xstrdup(path);
3961                return argcount;
3962        }
3963        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3964                int offending = parse_diff_filter_opt(optarg, options);
3965                if (offending)
3966                        die("unknown change class '%c' in --diff-filter=%s",
3967                            offending, optarg);
3968                return argcount;
3969        }
3970        else if (!strcmp(arg, "--abbrev"))
3971                options->abbrev = DEFAULT_ABBREV;
3972        else if (skip_prefix(arg, "--abbrev=", &arg)) {
3973                options->abbrev = strtoul(arg, NULL, 10);
3974                if (options->abbrev < MINIMUM_ABBREV)
3975                        options->abbrev = MINIMUM_ABBREV;
3976                else if (40 < options->abbrev)
3977                        options->abbrev = 40;
3978        }
3979        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3980                options->a_prefix = optarg;
3981                return argcount;
3982        }
3983        else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
3984                options->line_prefix = optarg;
3985                options->line_prefix_length = strlen(options->line_prefix);
3986                graph_setup_line_prefix(options);
3987                return argcount;
3988        }
3989        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3990                options->b_prefix = optarg;
3991                return argcount;
3992        }
3993        else if (!strcmp(arg, "--no-prefix"))
3994                options->a_prefix = options->b_prefix = "";
3995        else if (opt_arg(arg, '\0', "inter-hunk-context",
3996                         &options->interhunkcontext))
3997                ;
3998        else if (!strcmp(arg, "-W"))
3999                DIFF_OPT_SET(options, FUNCCONTEXT);
4000        else if (!strcmp(arg, "--function-context"))
4001                DIFF_OPT_SET(options, FUNCCONTEXT);
4002        else if (!strcmp(arg, "--no-function-context"))
4003                DIFF_OPT_CLR(options, FUNCCONTEXT);
4004        else if ((argcount = parse_long_opt("output", av, &optarg))) {
4005                const char *path = prefix_filename(prefix, strlen(prefix), optarg);
4006                options->file = fopen(path, "w");
4007                if (!options->file)
4008                        die_errno("Could not open '%s'", path);
4009                options->close_file = 1;
4010                if (options->use_color != GIT_COLOR_ALWAYS)
4011                        options->use_color = GIT_COLOR_NEVER;
4012                return argcount;
4013        } else
4014                return 0;
4015        return 1;
4016}
4017
4018int parse_rename_score(const char **cp_p)
4019{
4020        unsigned long num, scale;
4021        int ch, dot;
4022        const char *cp = *cp_p;
4023
4024        num = 0;
4025        scale = 1;
4026        dot = 0;
4027        for (;;) {
4028                ch = *cp;
4029                if ( !dot && ch == '.' ) {
4030                        scale = 1;
4031                        dot = 1;
4032                } else if ( ch == '%' ) {
4033                        scale = dot ? scale*100 : 100;
4034                        cp++;   /* % is always at the end */
4035                        break;
4036                } else if ( ch >= '0' && ch <= '9' ) {
4037                        if ( scale < 100000 ) {
4038                                scale *= 10;
4039                                num = (num*10) + (ch-'0');
4040                        }
4041                } else {
4042                        break;
4043                }
4044                cp++;
4045        }
4046        *cp_p = cp;
4047
4048        /* user says num divided by scale and we say internally that
4049         * is MAX_SCORE * num / scale.
4050         */
4051        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4052}
4053
4054static int diff_scoreopt_parse(const char *opt)
4055{
4056        int opt1, opt2, cmd;
4057
4058        if (*opt++ != '-')
4059                return -1;
4060        cmd = *opt++;
4061        if (cmd == '-') {
4062                /* convert the long-form arguments into short-form versions */
4063                if (skip_prefix(opt, "break-rewrites", &opt)) {
4064                        if (*opt == 0 || *opt++ == '=')
4065                                cmd = 'B';
4066                } else if (skip_prefix(opt, "find-copies", &opt)) {
4067                        if (*opt == 0 || *opt++ == '=')
4068                                cmd = 'C';
4069                } else if (skip_prefix(opt, "find-renames", &opt)) {
4070                        if (*opt == 0 || *opt++ == '=')
4071                                cmd = 'M';
4072                }
4073        }
4074        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4075                return -1; /* that is not a -M, -C, or -B option */
4076
4077        opt1 = parse_rename_score(&opt);
4078        if (cmd != 'B')
4079                opt2 = 0;
4080        else {
4081                if (*opt == 0)
4082                        opt2 = 0;
4083                else if (*opt != '/')
4084                        return -1; /* we expect -B80/99 or -B80 */
4085                else {
4086                        opt++;
4087                        opt2 = parse_rename_score(&opt);
4088                }
4089        }
4090        if (*opt != 0)
4091                return -1;
4092        return opt1 | (opt2 << 16);
4093}
4094
4095struct diff_queue_struct diff_queued_diff;
4096
4097void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4098{
4099        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4100        queue->queue[queue->nr++] = dp;
4101}
4102
4103struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4104                                 struct diff_filespec *one,
4105                                 struct diff_filespec *two)
4106{
4107        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4108        dp->one = one;
4109        dp->two = two;
4110        if (queue)
4111                diff_q(queue, dp);
4112        return dp;
4113}
4114
4115void diff_free_filepair(struct diff_filepair *p)
4116{
4117        free_filespec(p->one);
4118        free_filespec(p->two);
4119        free(p);
4120}
4121
4122/* This is different from find_unique_abbrev() in that
4123 * it stuffs the result with dots for alignment.
4124 */
4125const char *diff_unique_abbrev(const unsigned char *sha1, int len)
4126{
4127        int abblen;
4128        const char *abbrev;
4129        if (len == 40)
4130                return sha1_to_hex(sha1);
4131
4132        abbrev = find_unique_abbrev(sha1, len);
4133        abblen = strlen(abbrev);
4134        if (abblen < 37) {
4135                static char hex[41];
4136                if (len < abblen && abblen <= len + 2)
4137                        xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4138                else
4139                        xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4140                return hex;
4141        }
4142        return sha1_to_hex(sha1);
4143}
4144
4145static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4146{
4147        int line_termination = opt->line_termination;
4148        int inter_name_termination = line_termination ? '\t' : '\0';
4149
4150        fprintf(opt->file, "%s", diff_line_prefix(opt));
4151        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4152                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4153                        diff_unique_abbrev(p->one->oid.hash, opt->abbrev));
4154                fprintf(opt->file, "%s ",
4155                        diff_unique_abbrev(p->two->oid.hash, opt->abbrev));
4156        }
4157        if (p->score) {
4158                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4159                        inter_name_termination);
4160        } else {
4161                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4162        }
4163
4164        if (p->status == DIFF_STATUS_COPIED ||
4165            p->status == DIFF_STATUS_RENAMED) {
4166                const char *name_a, *name_b;
4167                name_a = p->one->path;
4168                name_b = p->two->path;
4169                strip_prefix(opt->prefix_length, &name_a, &name_b);
4170                write_name_quoted(name_a, opt->file, inter_name_termination);
4171                write_name_quoted(name_b, opt->file, line_termination);
4172        } else {
4173                const char *name_a, *name_b;
4174                name_a = p->one->mode ? p->one->path : p->two->path;
4175                name_b = NULL;
4176                strip_prefix(opt->prefix_length, &name_a, &name_b);
4177                write_name_quoted(name_a, opt->file, line_termination);
4178        }
4179}
4180
4181int diff_unmodified_pair(struct diff_filepair *p)
4182{
4183        /* This function is written stricter than necessary to support
4184         * the currently implemented transformers, but the idea is to
4185         * let transformers to produce diff_filepairs any way they want,
4186         * and filter and clean them up here before producing the output.
4187         */
4188        struct diff_filespec *one = p->one, *two = p->two;
4189
4190        if (DIFF_PAIR_UNMERGED(p))
4191                return 0; /* unmerged is interesting */
4192
4193        /* deletion, addition, mode or type change
4194         * and rename are all interesting.
4195         */
4196        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4197            DIFF_PAIR_MODE_CHANGED(p) ||
4198            strcmp(one->path, two->path))
4199                return 0;
4200
4201        /* both are valid and point at the same path.  that is, we are
4202         * dealing with a change.
4203         */
4204        if (one->oid_valid && two->oid_valid &&
4205            !oidcmp(&one->oid, &two->oid) &&
4206            !one->dirty_submodule && !two->dirty_submodule)
4207                return 1; /* no change */
4208        if (!one->oid_valid && !two->oid_valid)
4209                return 1; /* both look at the same file on the filesystem. */
4210        return 0;
4211}
4212
4213static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4214{
4215        if (diff_unmodified_pair(p))
4216                return;
4217
4218        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4219            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4220                return; /* no tree diffs in patch format */
4221
4222        run_diff(p, o);
4223}
4224
4225static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4226                            struct diffstat_t *diffstat)
4227{
4228        if (diff_unmodified_pair(p))
4229                return;
4230
4231        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4232            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4233                return; /* no useful stat for tree diffs */
4234
4235        run_diffstat(p, o, diffstat);
4236}
4237
4238static void diff_flush_checkdiff(struct diff_filepair *p,
4239                struct diff_options *o)
4240{
4241        if (diff_unmodified_pair(p))
4242                return;
4243
4244        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4245            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4246                return; /* nothing to check in tree diffs */
4247
4248        run_checkdiff(p, o);
4249}
4250
4251int diff_queue_is_empty(void)
4252{
4253        struct diff_queue_struct *q = &diff_queued_diff;
4254        int i;
4255        for (i = 0; i < q->nr; i++)
4256                if (!diff_unmodified_pair(q->queue[i]))
4257                        return 0;
4258        return 1;
4259}
4260
4261#if DIFF_DEBUG
4262void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4263{
4264        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4265                x, one ? one : "",
4266                s->path,
4267                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4268                s->mode,
4269                s->oid_valid ? oid_to_hex(&s->oid) : "");
4270        fprintf(stderr, "queue[%d] %s size %lu\n",
4271                x, one ? one : "",
4272                s->size);
4273}
4274
4275void diff_debug_filepair(const struct diff_filepair *p, int i)
4276{
4277        diff_debug_filespec(p->one, i, "one");
4278        diff_debug_filespec(p->two, i, "two");
4279        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4280                p->score, p->status ? p->status : '?',
4281                p->one->rename_used, p->broken_pair);
4282}
4283
4284void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4285{
4286        int i;
4287        if (msg)
4288                fprintf(stderr, "%s\n", msg);
4289        fprintf(stderr, "q->nr = %d\n", q->nr);
4290        for (i = 0; i < q->nr; i++) {
4291                struct diff_filepair *p = q->queue[i];
4292                diff_debug_filepair(p, i);
4293        }
4294}
4295#endif
4296
4297static void diff_resolve_rename_copy(void)
4298{
4299        int i;
4300        struct diff_filepair *p;
4301        struct diff_queue_struct *q = &diff_queued_diff;
4302
4303        diff_debug_queue("resolve-rename-copy", q);
4304
4305        for (i = 0; i < q->nr; i++) {
4306                p = q->queue[i];
4307                p->status = 0; /* undecided */
4308                if (DIFF_PAIR_UNMERGED(p))
4309                        p->status = DIFF_STATUS_UNMERGED;
4310                else if (!DIFF_FILE_VALID(p->one))
4311                        p->status = DIFF_STATUS_ADDED;
4312                else if (!DIFF_FILE_VALID(p->two))
4313                        p->status = DIFF_STATUS_DELETED;
4314                else if (DIFF_PAIR_TYPE_CHANGED(p))
4315                        p->status = DIFF_STATUS_TYPE_CHANGED;
4316
4317                /* from this point on, we are dealing with a pair
4318                 * whose both sides are valid and of the same type, i.e.
4319                 * either in-place edit or rename/copy edit.
4320                 */
4321                else if (DIFF_PAIR_RENAME(p)) {
4322                        /*
4323                         * A rename might have re-connected a broken
4324                         * pair up, causing the pathnames to be the
4325                         * same again. If so, that's not a rename at
4326                         * all, just a modification..
4327                         *
4328                         * Otherwise, see if this source was used for
4329                         * multiple renames, in which case we decrement
4330                         * the count, and call it a copy.
4331                         */
4332                        if (!strcmp(p->one->path, p->two->path))
4333                                p->status = DIFF_STATUS_MODIFIED;
4334                        else if (--p->one->rename_used > 0)
4335                                p->status = DIFF_STATUS_COPIED;
4336                        else
4337                                p->status = DIFF_STATUS_RENAMED;
4338                }
4339                else if (oidcmp(&p->one->oid, &p->two->oid) ||
4340                         p->one->mode != p->two->mode ||
4341                         p->one->dirty_submodule ||
4342                         p->two->dirty_submodule ||
4343                         is_null_oid(&p->one->oid))
4344                        p->status = DIFF_STATUS_MODIFIED;
4345                else {
4346                        /* This is a "no-change" entry and should not
4347                         * happen anymore, but prepare for broken callers.
4348                         */
4349                        error("feeding unmodified %s to diffcore",
4350                              p->one->path);
4351                        p->status = DIFF_STATUS_UNKNOWN;
4352                }
4353        }
4354        diff_debug_queue("resolve-rename-copy done", q);
4355}
4356
4357static int check_pair_status(struct diff_filepair *p)
4358{
4359        switch (p->status) {
4360        case DIFF_STATUS_UNKNOWN:
4361                return 0;
4362        case 0:
4363                die("internal error in diff-resolve-rename-copy");
4364        default:
4365                return 1;
4366        }
4367}
4368
4369static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4370{
4371        int fmt = opt->output_format;
4372
4373        if (fmt & DIFF_FORMAT_CHECKDIFF)
4374                diff_flush_checkdiff(p, opt);
4375        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4376                diff_flush_raw(p, opt);
4377        else if (fmt & DIFF_FORMAT_NAME) {
4378                const char *name_a, *name_b;
4379                name_a = p->two->path;
4380                name_b = NULL;
4381                strip_prefix(opt->prefix_length, &name_a, &name_b);
4382                write_name_quoted(name_a, opt->file, opt->line_termination);
4383        }
4384}
4385
4386static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4387{
4388        if (fs->mode)
4389                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4390        else
4391                fprintf(file, " %s ", newdelete);
4392        write_name_quoted(fs->path, file, '\n');
4393}
4394
4395
4396static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4397                const char *line_prefix)
4398{
4399        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4400                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4401                        p->two->mode, show_name ? ' ' : '\n');
4402                if (show_name) {
4403                        write_name_quoted(p->two->path, file, '\n');
4404                }
4405        }
4406}
4407
4408static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4409                        const char *line_prefix)
4410{
4411        char *names = pprint_rename(p->one->path, p->two->path);
4412
4413        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4414        free(names);
4415        show_mode_change(file, p, 0, line_prefix);
4416}
4417
4418static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4419{
4420        FILE *file = opt->file;
4421        const char *line_prefix = diff_line_prefix(opt);
4422
4423        switch(p->status) {
4424        case DIFF_STATUS_DELETED:
4425                fputs(line_prefix, file);
4426                show_file_mode_name(file, "delete", p->one);
4427                break;
4428        case DIFF_STATUS_ADDED:
4429                fputs(line_prefix, file);
4430                show_file_mode_name(file, "create", p->two);
4431                break;
4432        case DIFF_STATUS_COPIED:
4433                fputs(line_prefix, file);
4434                show_rename_copy(file, "copy", p, line_prefix);
4435                break;
4436        case DIFF_STATUS_RENAMED:
4437                fputs(line_prefix, file);
4438                show_rename_copy(file, "rename", p, line_prefix);
4439                break;
4440        default:
4441                if (p->score) {
4442                        fprintf(file, "%s rewrite ", line_prefix);
4443                        write_name_quoted(p->two->path, file, ' ');
4444                        fprintf(file, "(%d%%)\n", similarity_index(p));
4445                }
4446                show_mode_change(file, p, !p->score, line_prefix);
4447                break;
4448        }
4449}
4450
4451struct patch_id_t {
4452        git_SHA_CTX *ctx;
4453        int patchlen;
4454};
4455
4456static int remove_space(char *line, int len)
4457{
4458        int i;
4459        char *dst = line;
4460        unsigned char c;
4461
4462        for (i = 0; i < len; i++)
4463                if (!isspace((c = line[i])))
4464                        *dst++ = c;
4465
4466        return dst - line;
4467}
4468
4469static void patch_id_consume(void *priv, char *line, unsigned long len)
4470{
4471        struct patch_id_t *data = priv;
4472        int new_len;
4473
4474        /* Ignore line numbers when computing the SHA1 of the patch */
4475        if (starts_with(line, "@@ -"))
4476                return;
4477
4478        new_len = remove_space(line, len);
4479
4480        git_SHA1_Update(data->ctx, line, new_len);
4481        data->patchlen += new_len;
4482}
4483
4484/* returns 0 upon success, and writes result into sha1 */
4485static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1, int diff_header_only)
4486{
4487        struct diff_queue_struct *q = &diff_queued_diff;
4488        int i;
4489        git_SHA_CTX ctx;
4490        struct patch_id_t data;
4491        char buffer[PATH_MAX * 4 + 20];
4492
4493        git_SHA1_Init(&ctx);
4494        memset(&data, 0, sizeof(struct patch_id_t));
4495        data.ctx = &ctx;
4496
4497        for (i = 0; i < q->nr; i++) {
4498                xpparam_t xpp;
4499                xdemitconf_t xecfg;
4500                mmfile_t mf1, mf2;
4501                struct diff_filepair *p = q->queue[i];
4502                int len1, len2;
4503
4504                memset(&xpp, 0, sizeof(xpp));
4505                memset(&xecfg, 0, sizeof(xecfg));
4506                if (p->status == 0)
4507                        return error("internal diff status error");
4508                if (p->status == DIFF_STATUS_UNKNOWN)
4509                        continue;
4510                if (diff_unmodified_pair(p))
4511                        continue;
4512                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4513                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4514                        continue;
4515                if (DIFF_PAIR_UNMERGED(p))
4516                        continue;
4517
4518                diff_fill_sha1_info(p->one);
4519                diff_fill_sha1_info(p->two);
4520
4521                len1 = remove_space(p->one->path, strlen(p->one->path));
4522                len2 = remove_space(p->two->path, strlen(p->two->path));
4523                if (p->one->mode == 0)
4524                        len1 = snprintf(buffer, sizeof(buffer),
4525                                        "diff--gita/%.*sb/%.*s"
4526                                        "newfilemode%06o"
4527                                        "---/dev/null"
4528                                        "+++b/%.*s",
4529                                        len1, p->one->path,
4530                                        len2, p->two->path,
4531                                        p->two->mode,
4532                                        len2, p->two->path);
4533                else if (p->two->mode == 0)
4534                        len1 = snprintf(buffer, sizeof(buffer),
4535                                        "diff--gita/%.*sb/%.*s"
4536                                        "deletedfilemode%06o"
4537                                        "---a/%.*s"
4538                                        "+++/dev/null",
4539                                        len1, p->one->path,
4540                                        len2, p->two->path,
4541                                        p->one->mode,
4542                                        len1, p->one->path);
4543                else
4544                        len1 = snprintf(buffer, sizeof(buffer),
4545                                        "diff--gita/%.*sb/%.*s"
4546                                        "---a/%.*s"
4547                                        "+++b/%.*s",
4548                                        len1, p->one->path,
4549                                        len2, p->two->path,
4550                                        len1, p->one->path,
4551                                        len2, p->two->path);
4552                git_SHA1_Update(&ctx, buffer, len1);
4553
4554                if (diff_header_only)
4555                        continue;
4556
4557                if (fill_mmfile(&mf1, p->one) < 0 ||
4558                    fill_mmfile(&mf2, p->two) < 0)
4559                        return error("unable to read files to diff");
4560
4561                if (diff_filespec_is_binary(p->one) ||
4562                    diff_filespec_is_binary(p->two)) {
4563                        git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
4564                                        40);
4565                        git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
4566                                        40);
4567                        continue;
4568                }
4569
4570                xpp.flags = 0;
4571                xecfg.ctxlen = 3;
4572                xecfg.flags = 0;
4573                if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4574                                  &xpp, &xecfg))
4575                        return error("unable to generate patch-id diff for %s",
4576                                     p->one->path);
4577        }
4578
4579        git_SHA1_Final(sha1, &ctx);
4580        return 0;
4581}
4582
4583int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1, int diff_header_only)
4584{
4585        struct diff_queue_struct *q = &diff_queued_diff;
4586        int i;
4587        int result = diff_get_patch_id(options, sha1, diff_header_only);
4588
4589        for (i = 0; i < q->nr; i++)
4590                diff_free_filepair(q->queue[i]);
4591
4592        free(q->queue);
4593        DIFF_QUEUE_CLEAR(q);
4594
4595        return result;
4596}
4597
4598static int is_summary_empty(const struct diff_queue_struct *q)
4599{
4600        int i;
4601
4602        for (i = 0; i < q->nr; i++) {
4603                const struct diff_filepair *p = q->queue[i];
4604
4605                switch (p->status) {
4606                case DIFF_STATUS_DELETED:
4607                case DIFF_STATUS_ADDED:
4608                case DIFF_STATUS_COPIED:
4609                case DIFF_STATUS_RENAMED:
4610                        return 0;
4611                default:
4612                        if (p->score)
4613                                return 0;
4614                        if (p->one->mode && p->two->mode &&
4615                            p->one->mode != p->two->mode)
4616                                return 0;
4617                        break;
4618                }
4619        }
4620        return 1;
4621}
4622
4623static const char rename_limit_warning[] =
4624"inexact rename detection was skipped due to too many files.";
4625
4626static const char degrade_cc_to_c_warning[] =
4627"only found copies from modified paths due to too many files.";
4628
4629static const char rename_limit_advice[] =
4630"you may want to set your %s variable to at least "
4631"%d and retry the command.";
4632
4633void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4634{
4635        if (degraded_cc)
4636                warning(degrade_cc_to_c_warning);
4637        else if (needed)
4638                warning(rename_limit_warning);
4639        else
4640                return;
4641        if (0 < needed && needed < 32767)
4642                warning(rename_limit_advice, varname, needed);
4643}
4644
4645void diff_flush(struct diff_options *options)
4646{
4647        struct diff_queue_struct *q = &diff_queued_diff;
4648        int i, output_format = options->output_format;
4649        int separator = 0;
4650        int dirstat_by_line = 0;
4651
4652        /*
4653         * Order: raw, stat, summary, patch
4654         * or:    name/name-status/checkdiff (other bits clear)
4655         */
4656        if (!q->nr)
4657                goto free_queue;
4658
4659        if (output_format & (DIFF_FORMAT_RAW |
4660                             DIFF_FORMAT_NAME |
4661                             DIFF_FORMAT_NAME_STATUS |
4662                             DIFF_FORMAT_CHECKDIFF)) {
4663                for (i = 0; i < q->nr; i++) {
4664                        struct diff_filepair *p = q->queue[i];
4665                        if (check_pair_status(p))
4666                                flush_one_pair(p, options);
4667                }
4668                separator++;
4669        }
4670
4671        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4672                dirstat_by_line = 1;
4673
4674        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4675            dirstat_by_line) {
4676                struct diffstat_t diffstat;
4677
4678                memset(&diffstat, 0, sizeof(struct diffstat_t));
4679                for (i = 0; i < q->nr; i++) {
4680                        struct diff_filepair *p = q->queue[i];
4681                        if (check_pair_status(p))
4682                                diff_flush_stat(p, options, &diffstat);
4683                }
4684                if (output_format & DIFF_FORMAT_NUMSTAT)
4685                        show_numstat(&diffstat, options);
4686                if (output_format & DIFF_FORMAT_DIFFSTAT)
4687                        show_stats(&diffstat, options);
4688                if (output_format & DIFF_FORMAT_SHORTSTAT)
4689                        show_shortstats(&diffstat, options);
4690                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4691                        show_dirstat_by_line(&diffstat, options);
4692                free_diffstat_info(&diffstat);
4693                separator++;
4694        }
4695        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4696                show_dirstat(options);
4697
4698        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4699                for (i = 0; i < q->nr; i++) {
4700                        diff_summary(options, q->queue[i]);
4701                }
4702                separator++;
4703        }
4704
4705        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4706            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4707            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4708                /*
4709                 * run diff_flush_patch for the exit status. setting
4710                 * options->file to /dev/null should be safe, because we
4711                 * aren't supposed to produce any output anyway.
4712                 */
4713                if (options->close_file)
4714                        fclose(options->file);
4715                options->file = fopen("/dev/null", "w");
4716                if (!options->file)
4717                        die_errno("Could not open /dev/null");
4718                options->close_file = 1;
4719                for (i = 0; i < q->nr; i++) {
4720                        struct diff_filepair *p = q->queue[i];
4721                        if (check_pair_status(p))
4722                                diff_flush_patch(p, options);
4723                        if (options->found_changes)
4724                                break;
4725                }
4726        }
4727
4728        if (output_format & DIFF_FORMAT_PATCH) {
4729                if (separator) {
4730                        fprintf(options->file, "%s%c",
4731                                diff_line_prefix(options),
4732                                options->line_termination);
4733                        if (options->stat_sep) {
4734                                /* attach patch instead of inline */
4735                                fputs(options->stat_sep, options->file);
4736                        }
4737                }
4738
4739                for (i = 0; i < q->nr; i++) {
4740                        struct diff_filepair *p = q->queue[i];
4741                        if (check_pair_status(p))
4742                                diff_flush_patch(p, options);
4743                }
4744        }
4745
4746        if (output_format & DIFF_FORMAT_CALLBACK)
4747                options->format_callback(q, options, options->format_callback_data);
4748
4749        for (i = 0; i < q->nr; i++)
4750                diff_free_filepair(q->queue[i]);
4751free_queue:
4752        free(q->queue);
4753        DIFF_QUEUE_CLEAR(q);
4754        if (options->close_file)
4755                fclose(options->file);
4756
4757        /*
4758         * Report the content-level differences with HAS_CHANGES;
4759         * diff_addremove/diff_change does not set the bit when
4760         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4761         */
4762        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4763                if (options->found_changes)
4764                        DIFF_OPT_SET(options, HAS_CHANGES);
4765                else
4766                        DIFF_OPT_CLR(options, HAS_CHANGES);
4767        }
4768}
4769
4770static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4771{
4772        return (((p->status == DIFF_STATUS_MODIFIED) &&
4773                 ((p->score &&
4774                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4775                  (!p->score &&
4776                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4777                ((p->status != DIFF_STATUS_MODIFIED) &&
4778                 filter_bit_tst(p->status, options)));
4779}
4780
4781static void diffcore_apply_filter(struct diff_options *options)
4782{
4783        int i;
4784        struct diff_queue_struct *q = &diff_queued_diff;
4785        struct diff_queue_struct outq;
4786
4787        DIFF_QUEUE_CLEAR(&outq);
4788
4789        if (!options->filter)
4790                return;
4791
4792        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4793                int found;
4794                for (i = found = 0; !found && i < q->nr; i++) {
4795                        if (match_filter(options, q->queue[i]))
4796                                found++;
4797                }
4798                if (found)
4799                        return;
4800
4801                /* otherwise we will clear the whole queue
4802                 * by copying the empty outq at the end of this
4803                 * function, but first clear the current entries
4804                 * in the queue.
4805                 */
4806                for (i = 0; i < q->nr; i++)
4807                        diff_free_filepair(q->queue[i]);
4808        }
4809        else {
4810                /* Only the matching ones */
4811                for (i = 0; i < q->nr; i++) {
4812                        struct diff_filepair *p = q->queue[i];
4813                        if (match_filter(options, p))
4814                                diff_q(&outq, p);
4815                        else
4816                                diff_free_filepair(p);
4817                }
4818        }
4819        free(q->queue);
4820        *q = outq;
4821}
4822
4823/* Check whether two filespecs with the same mode and size are identical */
4824static int diff_filespec_is_identical(struct diff_filespec *one,
4825                                      struct diff_filespec *two)
4826{
4827        if (S_ISGITLINK(one->mode))
4828                return 0;
4829        if (diff_populate_filespec(one, 0))
4830                return 0;
4831        if (diff_populate_filespec(two, 0))
4832                return 0;
4833        return !memcmp(one->data, two->data, one->size);
4834}
4835
4836static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4837{
4838        if (p->done_skip_stat_unmatch)
4839                return p->skip_stat_unmatch_result;
4840
4841        p->done_skip_stat_unmatch = 1;
4842        p->skip_stat_unmatch_result = 0;
4843        /*
4844         * 1. Entries that come from stat info dirtiness
4845         *    always have both sides (iow, not create/delete),
4846         *    one side of the object name is unknown, with
4847         *    the same mode and size.  Keep the ones that
4848         *    do not match these criteria.  They have real
4849         *    differences.
4850         *
4851         * 2. At this point, the file is known to be modified,
4852         *    with the same mode and size, and the object
4853         *    name of one side is unknown.  Need to inspect
4854         *    the identical contents.
4855         */
4856        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4857            !DIFF_FILE_VALID(p->two) ||
4858            (p->one->oid_valid && p->two->oid_valid) ||
4859            (p->one->mode != p->two->mode) ||
4860            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4861            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4862            (p->one->size != p->two->size) ||
4863            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4864                p->skip_stat_unmatch_result = 1;
4865        return p->skip_stat_unmatch_result;
4866}
4867
4868static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4869{
4870        int i;
4871        struct diff_queue_struct *q = &diff_queued_diff;
4872        struct diff_queue_struct outq;
4873        DIFF_QUEUE_CLEAR(&outq);
4874
4875        for (i = 0; i < q->nr; i++) {
4876                struct diff_filepair *p = q->queue[i];
4877
4878                if (diff_filespec_check_stat_unmatch(p))
4879                        diff_q(&outq, p);
4880                else {
4881                        /*
4882                         * The caller can subtract 1 from skip_stat_unmatch
4883                         * to determine how many paths were dirty only
4884                         * due to stat info mismatch.
4885                         */
4886                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4887                                diffopt->skip_stat_unmatch++;
4888                        diff_free_filepair(p);
4889                }
4890        }
4891        free(q->queue);
4892        *q = outq;
4893}
4894
4895static int diffnamecmp(const void *a_, const void *b_)
4896{
4897        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4898        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4899        const char *name_a, *name_b;
4900
4901        name_a = a->one ? a->one->path : a->two->path;
4902        name_b = b->one ? b->one->path : b->two->path;
4903        return strcmp(name_a, name_b);
4904}
4905
4906void diffcore_fix_diff_index(struct diff_options *options)
4907{
4908        struct diff_queue_struct *q = &diff_queued_diff;
4909        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4910}
4911
4912void diffcore_std(struct diff_options *options)
4913{
4914        /* NOTE please keep the following in sync with diff_tree_combined() */
4915        if (options->skip_stat_unmatch)
4916                diffcore_skip_stat_unmatch(options);
4917        if (!options->found_follow) {
4918                /* See try_to_follow_renames() in tree-diff.c */
4919                if (options->break_opt != -1)
4920                        diffcore_break(options->break_opt);
4921                if (options->detect_rename)
4922                        diffcore_rename(options);
4923                if (options->break_opt != -1)
4924                        diffcore_merge_broken();
4925        }
4926        if (options->pickaxe)
4927                diffcore_pickaxe(options);
4928        if (options->orderfile)
4929                diffcore_order(options->orderfile);
4930        if (!options->found_follow)
4931                /* See try_to_follow_renames() in tree-diff.c */
4932                diff_resolve_rename_copy();
4933        diffcore_apply_filter(options);
4934
4935        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4936                DIFF_OPT_SET(options, HAS_CHANGES);
4937        else
4938                DIFF_OPT_CLR(options, HAS_CHANGES);
4939
4940        options->found_follow = 0;
4941}
4942
4943int diff_result_code(struct diff_options *opt, int status)
4944{
4945        int result = 0;
4946
4947        diff_warn_rename_limit("diff.renameLimit",
4948                               opt->needed_rename_limit,
4949                               opt->degraded_cc_to_c);
4950        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4951            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4952                return status;
4953        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4954            DIFF_OPT_TST(opt, HAS_CHANGES))
4955                result |= 01;
4956        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4957            DIFF_OPT_TST(opt, CHECK_FAILED))
4958                result |= 02;
4959        return result;
4960}
4961
4962int diff_can_quit_early(struct diff_options *opt)
4963{
4964        return (DIFF_OPT_TST(opt, QUICK) &&
4965                !opt->filter &&
4966                DIFF_OPT_TST(opt, HAS_CHANGES));
4967}
4968
4969/*
4970 * Shall changes to this submodule be ignored?
4971 *
4972 * Submodule changes can be configured to be ignored separately for each path,
4973 * but that configuration can be overridden from the command line.
4974 */
4975static int is_submodule_ignored(const char *path, struct diff_options *options)
4976{
4977        int ignored = 0;
4978        unsigned orig_flags = options->flags;
4979        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4980                set_diffopt_flags_from_submodule_config(options, path);
4981        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4982                ignored = 1;
4983        options->flags = orig_flags;
4984        return ignored;
4985}
4986
4987void diff_addremove(struct diff_options *options,
4988                    int addremove, unsigned mode,
4989                    const unsigned char *sha1,
4990                    int sha1_valid,
4991                    const char *concatpath, unsigned dirty_submodule)
4992{
4993        struct diff_filespec *one, *two;
4994
4995        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4996                return;
4997
4998        /* This may look odd, but it is a preparation for
4999         * feeding "there are unchanged files which should
5000         * not produce diffs, but when you are doing copy
5001         * detection you would need them, so here they are"
5002         * entries to the diff-core.  They will be prefixed
5003         * with something like '=' or '*' (I haven't decided
5004         * which but should not make any difference).
5005         * Feeding the same new and old to diff_change()
5006         * also has the same effect.
5007         * Before the final output happens, they are pruned after
5008         * merged into rename/copy pairs as appropriate.
5009         */
5010        if (DIFF_OPT_TST(options, REVERSE_DIFF))
5011                addremove = (addremove == '+' ? '-' :
5012                             addremove == '-' ? '+' : addremove);
5013
5014        if (options->prefix &&
5015            strncmp(concatpath, options->prefix, options->prefix_length))
5016                return;
5017
5018        one = alloc_filespec(concatpath);
5019        two = alloc_filespec(concatpath);
5020
5021        if (addremove != '+')
5022                fill_filespec(one, sha1, sha1_valid, mode);
5023        if (addremove != '-') {
5024                fill_filespec(two, sha1, sha1_valid, mode);
5025                two->dirty_submodule = dirty_submodule;
5026        }
5027
5028        diff_queue(&diff_queued_diff, one, two);
5029        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5030                DIFF_OPT_SET(options, HAS_CHANGES);
5031}
5032
5033void diff_change(struct diff_options *options,
5034                 unsigned old_mode, unsigned new_mode,
5035                 const unsigned char *old_sha1,
5036                 const unsigned char *new_sha1,
5037                 int old_sha1_valid, int new_sha1_valid,
5038                 const char *concatpath,
5039                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5040{
5041        struct diff_filespec *one, *two;
5042        struct diff_filepair *p;
5043
5044        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5045            is_submodule_ignored(concatpath, options))
5046                return;
5047
5048        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5049                unsigned tmp;
5050                const unsigned char *tmp_c;
5051                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
5052                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
5053                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
5054                        new_sha1_valid = tmp;
5055                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
5056                        new_dirty_submodule = tmp;
5057        }
5058
5059        if (options->prefix &&
5060            strncmp(concatpath, options->prefix, options->prefix_length))
5061                return;
5062
5063        one = alloc_filespec(concatpath);
5064        two = alloc_filespec(concatpath);
5065        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
5066        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
5067        one->dirty_submodule = old_dirty_submodule;
5068        two->dirty_submodule = new_dirty_submodule;
5069        p = diff_queue(&diff_queued_diff, one, two);
5070
5071        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5072                return;
5073
5074        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5075            !diff_filespec_check_stat_unmatch(p))
5076                return;
5077
5078        DIFF_OPT_SET(options, HAS_CHANGES);
5079}
5080
5081struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5082{
5083        struct diff_filepair *pair;
5084        struct diff_filespec *one, *two;
5085
5086        if (options->prefix &&
5087            strncmp(path, options->prefix, options->prefix_length))
5088                return NULL;
5089
5090        one = alloc_filespec(path);
5091        two = alloc_filespec(path);
5092        pair = diff_queue(&diff_queued_diff, one, two);
5093        pair->is_unmerged = 1;
5094        return pair;
5095}
5096
5097static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5098                size_t *outsize)
5099{
5100        struct diff_tempfile *temp;
5101        const char *argv[3];
5102        const char **arg = argv;
5103        struct child_process child = CHILD_PROCESS_INIT;
5104        struct strbuf buf = STRBUF_INIT;
5105        int err = 0;
5106
5107        temp = prepare_temp_file(spec->path, spec);
5108        *arg++ = pgm;
5109        *arg++ = temp->name;
5110        *arg = NULL;
5111
5112        child.use_shell = 1;
5113        child.argv = argv;
5114        child.out = -1;
5115        if (start_command(&child)) {
5116                remove_tempfile();
5117                return NULL;
5118        }
5119
5120        if (strbuf_read(&buf, child.out, 0) < 0)
5121                err = error("error reading from textconv command '%s'", pgm);
5122        close(child.out);
5123
5124        if (finish_command(&child) || err) {
5125                strbuf_release(&buf);
5126                remove_tempfile();
5127                return NULL;
5128        }
5129        remove_tempfile();
5130
5131        return strbuf_detach(&buf, outsize);
5132}
5133
5134size_t fill_textconv(struct userdiff_driver *driver,
5135                     struct diff_filespec *df,
5136                     char **outbuf)
5137{
5138        size_t size;
5139
5140        if (!driver) {
5141                if (!DIFF_FILE_VALID(df)) {
5142                        *outbuf = "";
5143                        return 0;
5144                }
5145                if (diff_populate_filespec(df, 0))
5146                        die("unable to read files to diff");
5147                *outbuf = df->data;
5148                return df->size;
5149        }
5150
5151        if (!driver->textconv)
5152                die("BUG: fill_textconv called with non-textconv driver");
5153
5154        if (driver->textconv_cache && df->oid_valid) {
5155                *outbuf = notes_cache_get(driver->textconv_cache,
5156                                          df->oid.hash,
5157                                          &size);
5158                if (*outbuf)
5159                        return size;
5160        }
5161
5162        *outbuf = run_textconv(driver->textconv, df, &size);
5163        if (!*outbuf)
5164                die("unable to read files to diff");
5165
5166        if (driver->textconv_cache && df->oid_valid) {
5167                /* ignore errors, as we might be in a readonly repository */
5168                notes_cache_put(driver->textconv_cache, df->oid.hash, *outbuf,
5169                                size);
5170                /*
5171                 * we could save up changes and flush them all at the end,
5172                 * but we would need an extra call after all diffing is done.
5173                 * Since generating a cache entry is the slow path anyway,
5174                 * this extra overhead probably isn't a big deal.
5175                 */
5176                notes_cache_write(driver->textconv_cache);
5177        }
5178
5179        return size;
5180}
5181
5182void setup_diff_pager(struct diff_options *opt)
5183{
5184        /*
5185         * If the user asked for our exit code, then either they want --quiet
5186         * or --exit-code. We should definitely not bother with a pager in the
5187         * former case, as we will generate no output. Since we still properly
5188         * report our exit code even when a pager is run, we _could_ run a
5189         * pager with --exit-code. But since we have not done so historically,
5190         * and because it is easy to find people oneline advising "git diff
5191         * --exit-code" in hooks and other scripts, we do not do so.
5192         */
5193        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5194            check_pager_config("diff") != 0)
5195                setup_pager();
5196}