diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "quote.h"
   6 #include "diff.h"
   7 #include "diffcore.h"
   8 #include "delta.h"
   9 #include "xdiff-interface.h"
  10 #include "color.h"
  11 #include "attr.h"
  12 #include "run-command.h"
  13 #include "utf8.h"
  14
  15 #ifdef NO_FAST_WORKING_DIRECTORY
  16 #define FAST_WORKING_DIRECTORY 0
  17 #else
  18 #define FAST_WORKING_DIRECTORY 1
  19 #endif
  20
  21 static int diff_detect_rename_default;
  22 static int diff_rename_limit_default = 200;
  23 static int diff_suppress_blank_empty;
  24 int diff_use_color_default = -1;
  25 static const char *external_diff_cmd_cfg;
  26 int diff_auto_refresh_index = 1;
  27
  28 static char diff_colors[][COLOR_MAXLEN] = {
  29         "\033[m",       /* reset */
  30         "",             /* PLAIN (normal) */
  31         "\033[1m",      /* METAINFO (bold) */
  32         "\033[36m",     /* FRAGINFO (cyan) */
  33         "\033[31m",     /* OLD (red) */
  34         "\033[32m",     /* NEW (green) */
  35         "\033[33m",     /* COMMIT (yellow) */
  36         "\033[41m",     /* WHITESPACE (red background) */
  37 };
  38
  39 static int parse_diff_color_slot(const char *var, int ofs)
  40 {
  41         if (!strcasecmp(var+ofs, "plain"))
  42                 return DIFF_PLAIN;
  43         if (!strcasecmp(var+ofs, "meta"))
  44                 return DIFF_METAINFO;
  45         if (!strcasecmp(var+ofs, "frag"))
  46                 return DIFF_FRAGINFO;
  47         if (!strcasecmp(var+ofs, "old"))
  48                 return DIFF_FILE_OLD;
  49         if (!strcasecmp(var+ofs, "new"))
  50                 return DIFF_FILE_NEW;
  51         if (!strcasecmp(var+ofs, "commit"))
  52                 return DIFF_COMMIT;
  53         if (!strcasecmp(var+ofs, "whitespace"))
  54                 return DIFF_WHITESPACE;
  55         die("bad config variable '%s'", var);
  56 }
  57
  58 static struct ll_diff_driver {
  59         const char *name;
  60         struct ll_diff_driver *next;
  61         const char *cmd;
  62 } *user_diff, **user_diff_tail;
  63
  64 /*
  65  * Currently there is only "diff.<drivername>.command" variable;
  66  * because there are "diff.color.<slot>" variables, we are parsing
  67  * this in a bit convoluted way to allow low level diff driver
  68  * called "color".
  69  */
  70 static int parse_lldiff_command(const char *var, const char *ep, const char *value)
  71 {
  72         const char *name;
  73         int namelen;
  74         struct ll_diff_driver *drv;
  75
  76         name = var + 5;
  77         namelen = ep - name;
  78         for (drv = user_diff; drv; drv = drv->next)
  79                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
  80                         break;
  81         if (!drv) {
  82                 drv = xcalloc(1, sizeof(struct ll_diff_driver));
  83                 drv->name = xmemdupz(name, namelen);
  84                 if (!user_diff_tail)
  85                         user_diff_tail = &user_diff;
  86                 *user_diff_tail = drv;
  87                 user_diff_tail = &(drv->next);
  88         }
  89
  90         return git_config_string(&(drv->cmd), var, value);
  91 }
  92
  93 /*
  94  * 'diff.<what>.funcname' attribute can be specified in the configuration
  95  * to define a customized regexp to find the beginning of a function to
  96  * be used for hunk header lines of "diff -p" style output.
  97  */
  98 static struct funcname_pattern {
  99         char *name;
 100         char *pattern;
 101         struct funcname_pattern *next;
 102 } *funcname_pattern_list;
 103
 104 static int parse_funcname_pattern(const char *var, const char *ep, const char *value)
 105 {
 106         const char *name;
 107         int namelen;
 108         struct funcname_pattern *pp;
 109
 110         name = var + 5; /* "diff." */
 111         namelen = ep - name;
 112
 113         for (pp = funcname_pattern_list; pp; pp = pp->next)
 114                 if (!strncmp(pp->name, name, namelen) && !pp->name[namelen])
 115                         break;
 116         if (!pp) {
 117                 pp = xcalloc(1, sizeof(*pp));
 118                 pp->name = xmemdupz(name, namelen);
 119                 pp->next = funcname_pattern_list;
 120                 funcname_pattern_list = pp;
 121         }
 122         free(pp->pattern);
 123         pp->pattern = xstrdup(value);
 124         return 0;
 125 }
 126
 127 /*
 128  * These are to give UI layer defaults.
 129  * The core-level commands such as git-diff-files should
 130  * never be affected by the setting of diff.renames
 131  * the user happens to have in the configuration file.
 132  */
 133 int git_diff_ui_config(const char *var, const char *value, void *cb)
 134 {
 135         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 136                 diff_use_color_default = git_config_colorbool(var, value, -1);
 137                 return 0;
 138         }
 139         if (!strcmp(var, "diff.renames")) {
 140                 if (!value)
 141                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 142                 else if (!strcasecmp(value, "copies") ||
 143                          !strcasecmp(value, "copy"))
 144                         diff_detect_rename_default = DIFF_DETECT_COPY;
 145                 else if (git_config_bool(var,value))
 146                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 147                 return 0;
 148         }
 149         if (!strcmp(var, "diff.autorefreshindex")) {
 150                 diff_auto_refresh_index = git_config_bool(var, value);
 151                 return 0;
 152         }
 153         if (!strcmp(var, "diff.external"))
 154                 return git_config_string(&external_diff_cmd_cfg, var, value);
 155         if (!prefixcmp(var, "diff.")) {
 156                 const char *ep = strrchr(var, '.');
 157
 158                 if (ep != var + 4 && !strcmp(ep, ".command"))
 159                         return parse_lldiff_command(var, ep, value);
 160         }
 161
 162         return git_diff_basic_config(var, value, cb);
 163 }
 164
 165 int git_diff_basic_config(const char *var, const char *value, void *cb)
 166 {
 167         if (!strcmp(var, "diff.renamelimit")) {
 168                 diff_rename_limit_default = git_config_int(var, value);
 169                 return 0;
 170         }
 171
 172         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 173                 int slot = parse_diff_color_slot(var, 11);
 174                 if (!value)
 175                         return config_error_nonbool(var);
 176                 color_parse(value, var, diff_colors[slot]);
 177                 return 0;
 178         }
 179
 180         /* like GNU diff's --suppress-blank-empty option  */
 181         if (!strcmp(var, "diff.suppress-blank-empty")) {
 182                 diff_suppress_blank_empty = git_config_bool(var, value);
 183                 return 0;
 184         }
 185
 186         if (!prefixcmp(var, "diff.")) {
 187                 const char *ep = strrchr(var, '.');
 188                 if (ep != var + 4) {
 189                         if (!strcmp(ep, ".funcname")) {
 190                                 if (!value)
 191                                         return config_error_nonbool(var);
 192                                 return parse_funcname_pattern(var, ep, value);
 193                         }
 194                 }
 195         }
 196
 197         return git_color_default_config(var, value, cb);
 198 }
 199
 200 static char *quote_two(const char *one, const char *two)
 201 {
 202         int need_one = quote_c_style(one, NULL, NULL, 1);
 203         int need_two = quote_c_style(two, NULL, NULL, 1);
 204         struct strbuf res;
 205
 206         strbuf_init(&res, 0);
 207         if (need_one + need_two) {
 208                 strbuf_addch(&res, '"');
 209                 quote_c_style(one, &res, NULL, 1);
 210                 quote_c_style(two, &res, NULL, 1);
 211                 strbuf_addch(&res, '"');
 212         } else {
 213                 strbuf_addstr(&res, one);
 214                 strbuf_addstr(&res, two);
 215         }
 216         return strbuf_detach(&res, NULL);
 217 }
 218
 219 static const char *external_diff(void)
 220 {
 221         static const char *external_diff_cmd = NULL;
 222         static int done_preparing = 0;
 223
 224         if (done_preparing)
 225                 return external_diff_cmd;
 226         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 227         if (!external_diff_cmd)
 228                 external_diff_cmd = external_diff_cmd_cfg;
 229         done_preparing = 1;
 230         return external_diff_cmd;
 231 }
 232
 233 static struct diff_tempfile {
 234         const char *name; /* filename external diff should read from */
 235         char hex[41];
 236         char mode[10];
 237         char tmp_path[PATH_MAX];
 238 } diff_temp[2];
 239
 240 static int count_lines(const char *data, int size)
 241 {
 242         int count, ch, completely_empty = 1, nl_just_seen = 0;
 243         count = 0;
 244         while (0 < size--) {
 245                 ch = *data++;
 246                 if (ch == '\n') {
 247                         count++;
 248                         nl_just_seen = 1;
 249                         completely_empty = 0;
 250                 }
 251                 else {
 252                         nl_just_seen = 0;
 253                         completely_empty = 0;
 254                 }
 255         }
 256         if (completely_empty)
 257                 return 0;
 258         if (!nl_just_seen)
 259                 count++; /* no trailing newline */
 260         return count;
 261 }
 262
 263 static void print_line_count(FILE *file, int count)
 264 {
 265         switch (count) {
 266         case 0:
 267                 fprintf(file, "0,0");
 268                 break;
 269         case 1:
 270                 fprintf(file, "1");
 271                 break;
 272         default:
 273                 fprintf(file, "1,%d", count);
 274                 break;
 275         }
 276 }
 277
 278 static void copy_file_with_prefix(FILE *file,
 279                                   int prefix, const char *data, int size,
 280                                   const char *set, const char *reset)
 281 {
 282         int ch, nl_just_seen = 1;
 283         while (0 < size--) {
 284                 ch = *data++;
 285                 if (nl_just_seen) {
 286                         fputs(set, file);
 287                         putc(prefix, file);
 288                 }
 289                 if (ch == '\n') {
 290                         nl_just_seen = 1;
 291                         fputs(reset, file);
 292                 } else
 293                         nl_just_seen = 0;
 294                 putc(ch, file);
 295         }
 296         if (!nl_just_seen)
 297                 fprintf(file, "%s\n\\ No newline at end of file\n", reset);
 298 }
 299
 300 static void emit_rewrite_diff(const char *name_a,
 301                               const char *name_b,
 302                               struct diff_filespec *one,
 303                               struct diff_filespec *two,
 304                               struct diff_options *o)
 305 {
 306         int lc_a, lc_b;
 307         int color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
 308         const char *name_a_tab, *name_b_tab;
 309         const char *metainfo = diff_get_color(color_diff, DIFF_METAINFO);
 310         const char *fraginfo = diff_get_color(color_diff, DIFF_FRAGINFO);
 311         const char *old = diff_get_color(color_diff, DIFF_FILE_OLD);
 312         const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
 313         const char *reset = diff_get_color(color_diff, DIFF_RESET);
 314         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 315
 316         name_a += (*name_a == '/');
 317         name_b += (*name_b == '/');
 318         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 319         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 320
 321         strbuf_reset(&a_name);
 322         strbuf_reset(&b_name);
 323         quote_two_c_style(&a_name, o->a_prefix, name_a, 0);
 324         quote_two_c_style(&b_name, o->b_prefix, name_b, 0);
 325
 326         diff_populate_filespec(one, 0);
 327         diff_populate_filespec(two, 0);
 328         lc_a = count_lines(one->data, one->size);
 329         lc_b = count_lines(two->data, two->size);
 330         fprintf(o->file,
 331                 "%s--- %s%s%s\n%s+++ %s%s%s\n%s@@ -",
 332                 metainfo, a_name.buf, name_a_tab, reset,
 333                 metainfo, b_name.buf, name_b_tab, reset, fraginfo);
 334         print_line_count(o->file, lc_a);
 335         fprintf(o->file, " +");
 336         print_line_count(o->file, lc_b);
 337         fprintf(o->file, " @@%s\n", reset);
 338         if (lc_a)
 339                 copy_file_with_prefix(o->file, '-', one->data, one->size, old, reset);
 340         if (lc_b)
 341                 copy_file_with_prefix(o->file, '+', two->data, two->size, new, reset);
 342 }
 343
 344 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 345 {
 346         if (!DIFF_FILE_VALID(one)) {
 347                 mf->ptr = (char *)""; /* does not matter */
 348                 mf->size = 0;
 349                 return 0;
 350         }
 351         else if (diff_populate_filespec(one, 0))
 352                 return -1;
 353         mf->ptr = one->data;
 354         mf->size = one->size;
 355         return 0;
 356 }
 357
 358 struct diff_words_buffer {
 359         mmfile_t text;
 360         long alloc;
 361         long current; /* output pointer */
 362         int suppressed_newline;
 363 };
 364
 365 static void diff_words_append(char *line, unsigned long len,
 366                 struct diff_words_buffer *buffer)
 367 {
 368         if (buffer->text.size + len > buffer->alloc) {
 369                 buffer->alloc = (buffer->text.size + len) * 3 / 2;
 370                 buffer->text.ptr = xrealloc(buffer->text.ptr, buffer->alloc);
 371         }
 372         line++;
 373         len--;
 374         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 375         buffer->text.size += len;
 376 }
 377
 378 struct diff_words_data {
 379         struct diff_words_buffer minus, plus;
 380         FILE *file;
 381 };
 382
 383 static void print_word(FILE *file, struct diff_words_buffer *buffer, int len, int color,
 384                 int suppress_newline)
 385 {
 386         const char *ptr;
 387         int eol = 0;
 388
 389         if (len == 0)
 390                 return;
 391
 392         ptr  = buffer->text.ptr + buffer->current;
 393         buffer->current += len;
 394
 395         if (ptr[len - 1] == '\n') {
 396                 eol = 1;
 397                 len--;
 398         }
 399
 400         fputs(diff_get_color(1, color), file);
 401         fwrite(ptr, len, 1, file);
 402         fputs(diff_get_color(1, DIFF_RESET), file);
 403
 404         if (eol) {
 405                 if (suppress_newline)
 406                         buffer->suppressed_newline = 1;
 407                 else
 408                         putc('\n', file);
 409         }
 410 }
 411
 412 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 413 {
 414         struct diff_words_data *diff_words = priv;
 415
 416         if (diff_words->minus.suppressed_newline) {
 417                 if (line[0] != '+')
 418                         putc('\n', diff_words->file);
 419                 diff_words->minus.suppressed_newline = 0;
 420         }
 421
 422         len--;
 423         switch (line[0]) {
 424                 case '-':
 425                         print_word(diff_words->file,
 426                                    &diff_words->minus, len, DIFF_FILE_OLD, 1);
 427                         break;
 428                 case '+':
 429                         print_word(diff_words->file,
 430                                    &diff_words->plus, len, DIFF_FILE_NEW, 0);
 431                         break;
 432                 case ' ':
 433                         print_word(diff_words->file,
 434                                    &diff_words->plus, len, DIFF_PLAIN, 0);
 435                         diff_words->minus.current += len;
 436                         break;
 437         }
 438 }
 439
 440 /* this executes the word diff on the accumulated buffers */
 441 static void diff_words_show(struct diff_words_data *diff_words)
 442 {
 443         xpparam_t xpp;
 444         xdemitconf_t xecfg;
 445         xdemitcb_t ecb;
 446         mmfile_t minus, plus;
 447         int i;
 448
 449         memset(&xecfg, 0, sizeof(xecfg));
 450         minus.size = diff_words->minus.text.size;
 451         minus.ptr = xmalloc(minus.size);
 452         memcpy(minus.ptr, diff_words->minus.text.ptr, minus.size);
 453         for (i = 0; i < minus.size; i++)
 454                 if (isspace(minus.ptr[i]))
 455                         minus.ptr[i] = '\n';
 456         diff_words->minus.current = 0;
 457
 458         plus.size = diff_words->plus.text.size;
 459         plus.ptr = xmalloc(plus.size);
 460         memcpy(plus.ptr, diff_words->plus.text.ptr, plus.size);
 461         for (i = 0; i < plus.size; i++)
 462                 if (isspace(plus.ptr[i]))
 463                         plus.ptr[i] = '\n';
 464         diff_words->plus.current = 0;
 465
 466         xpp.flags = XDF_NEED_MINIMAL;
 467         xecfg.ctxlen = diff_words->minus.alloc + diff_words->plus.alloc;
 468         xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
 469                       &xpp, &xecfg, &ecb);
 470         free(minus.ptr);
 471         free(plus.ptr);
 472         diff_words->minus.text.size = diff_words->plus.text.size = 0;
 473
 474         if (diff_words->minus.suppressed_newline) {
 475                 putc('\n', diff_words->file);
 476                 diff_words->minus.suppressed_newline = 0;
 477         }
 478 }
 479
 480 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 481
 482 struct emit_callback {
 483         int nparents, color_diff;
 484         unsigned ws_rule;
 485         sane_truncate_fn truncate;
 486         const char **label_path;
 487         struct diff_words_data *diff_words;
 488         int *found_changesp;
 489         FILE *file;
 490 };
 491
 492 static void free_diff_words_data(struct emit_callback *ecbdata)
 493 {
 494         if (ecbdata->diff_words) {
 495                 /* flush buffers */
 496                 if (ecbdata->diff_words->minus.text.size ||
 497                                 ecbdata->diff_words->plus.text.size)
 498                         diff_words_show(ecbdata->diff_words);
 499
 500                 free (ecbdata->diff_words->minus.text.ptr);
 501                 free (ecbdata->diff_words->plus.text.ptr);
 502                 free(ecbdata->diff_words);
 503                 ecbdata->diff_words = NULL;
 504         }
 505 }
 506
 507 const char *diff_get_color(int diff_use_color, enum color_diff ix)
 508 {
 509         if (diff_use_color)
 510                 return diff_colors[ix];
 511         return "";
 512 }
 513
 514 static void emit_line(FILE *file, const char *set, const char *reset, const char *line, int len)
 515 {
 516         int has_trailing_newline = (len > 0 && line[len-1] == '\n');
 517         if (has_trailing_newline)
 518                 len--;
 519
 520         fputs(set, file);
 521         fwrite(line, len, 1, file);
 522         fputs(reset, file);
 523         if (has_trailing_newline)
 524                 fputc('\n', file);
 525 }
 526
 527 static void emit_add_line(const char *reset, struct emit_callback *ecbdata, const char *line, int len)
 528 {
 529         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 530         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 531
 532         if (!*ws)
 533                 emit_line(ecbdata->file, set, reset, line, len);
 534         else {
 535                 /* Emit just the prefix, then the rest. */
 536                 emit_line(ecbdata->file, set, reset, line, ecbdata->nparents);
 537                 ws_check_emit(line + ecbdata->nparents,
 538                               len - ecbdata->nparents, ecbdata->ws_rule,
 539                               ecbdata->file, set, reset, ws);
 540         }
 541 }
 542
 543 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
 544 {
 545         const char *cp;
 546         unsigned long allot;
 547         size_t l = len;
 548
 549         if (ecb->truncate)
 550                 return ecb->truncate(line, len);
 551         cp = line;
 552         allot = l;
 553         while (0 < l) {
 554                 (void) utf8_width(&cp, &l);
 555                 if (!cp)
 556                         break; /* truncated in the middle? */
 557         }
 558         return allot - l;
 559 }
 560
 561 static void fn_out_consume(void *priv, char *line, unsigned long len)
 562 {
 563         int i;
 564         int color;
 565         struct emit_callback *ecbdata = priv;
 566         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
 567         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 568         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 569
 570         *(ecbdata->found_changesp) = 1;
 571
 572         if (ecbdata->label_path[0]) {
 573                 const char *name_a_tab, *name_b_tab;
 574
 575                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
 576                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
 577
 578                 fprintf(ecbdata->file, "%s--- %s%s%s\n",
 579                         meta, ecbdata->label_path[0], reset, name_a_tab);
 580                 fprintf(ecbdata->file, "%s+++ %s%s%s\n",
 581                         meta, ecbdata->label_path[1], reset, name_b_tab);
 582                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 583         }
 584
 585         if (diff_suppress_blank_empty
 586             && len == 2 && line[0] == ' ' && line[1] == '\n') {
 587                 line[0] = '\n';
 588                 len = 1;
 589         }
 590
 591         /* This is not really necessary for now because
 592          * this codepath only deals with two-way diffs.
 593          */
 594         for (i = 0; i < len && line[i] == '@'; i++)
 595                 ;
 596         if (2 <= i && i < len && line[i] == ' ') {
 597                 ecbdata->nparents = i - 1;
 598                 len = sane_truncate_line(ecbdata, line, len);
 599                 emit_line(ecbdata->file,
 600                           diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO),
 601                           reset, line, len);
 602                 if (line[len-1] != '\n')
 603                         putc('\n', ecbdata->file);
 604                 return;
 605         }
 606
 607         if (len < ecbdata->nparents) {
 608                 emit_line(ecbdata->file, reset, reset, line, len);
 609                 return;
 610         }
 611
 612         color = DIFF_PLAIN;
 613         if (ecbdata->diff_words && ecbdata->nparents != 1)
 614                 /* fall back to normal diff */
 615                 free_diff_words_data(ecbdata);
 616         if (ecbdata->diff_words) {
 617                 if (line[0] == '-') {
 618                         diff_words_append(line, len,
 619                                           &ecbdata->diff_words->minus);
 620                         return;
 621                 } else if (line[0] == '+') {
 622                         diff_words_append(line, len,
 623                                           &ecbdata->diff_words->plus);
 624                         return;
 625                 }
 626                 if (ecbdata->diff_words->minus.text.size ||
 627                     ecbdata->diff_words->plus.text.size)
 628                         diff_words_show(ecbdata->diff_words);
 629                 line++;
 630                 len--;
 631                 emit_line(ecbdata->file, plain, reset, line, len);
 632                 return;
 633         }
 634         for (i = 0; i < ecbdata->nparents && len; i++) {
 635                 if (line[i] == '-')
 636                         color = DIFF_FILE_OLD;
 637                 else if (line[i] == '+')
 638                         color = DIFF_FILE_NEW;
 639         }
 640
 641         if (color != DIFF_FILE_NEW) {
 642                 emit_line(ecbdata->file,
 643                           diff_get_color(ecbdata->color_diff, color),
 644                           reset, line, len);
 645                 return;
 646         }
 647         emit_add_line(reset, ecbdata, line, len);
 648 }
 649
 650 static char *pprint_rename(const char *a, const char *b)
 651 {
 652         const char *old = a;
 653         const char *new = b;
 654         struct strbuf name;
 655         int pfx_length, sfx_length;
 656         int len_a = strlen(a);
 657         int len_b = strlen(b);
 658         int a_midlen, b_midlen;
 659         int qlen_a = quote_c_style(a, NULL, NULL, 0);
 660         int qlen_b = quote_c_style(b, NULL, NULL, 0);
 661
 662         strbuf_init(&name, 0);
 663         if (qlen_a || qlen_b) {
 664                 quote_c_style(a, &name, NULL, 0);
 665                 strbuf_addstr(&name, " => ");
 666                 quote_c_style(b, &name, NULL, 0);
 667                 return strbuf_detach(&name, NULL);
 668         }
 669
 670         /* Find common prefix */
 671         pfx_length = 0;
 672         while (*old && *new && *old == *new) {
 673                 if (*old == '/')
 674                         pfx_length = old - a + 1;
 675                 old++;
 676                 new++;
 677         }
 678
 679         /* Find common suffix */
 680         old = a + len_a;
 681         new = b + len_b;
 682         sfx_length = 0;
 683         while (a <= old && b <= new && *old == *new) {
 684                 if (*old == '/')
 685                         sfx_length = len_a - (old - a);
 686                 old--;
 687                 new--;
 688         }
 689
 690         /*
 691          * pfx{mid-a => mid-b}sfx
 692          * {pfx-a => pfx-b}sfx
 693          * pfx{sfx-a => sfx-b}
 694          * name-a => name-b
 695          */
 696         a_midlen = len_a - pfx_length - sfx_length;
 697         b_midlen = len_b - pfx_length - sfx_length;
 698         if (a_midlen < 0)
 699                 a_midlen = 0;
 700         if (b_midlen < 0)
 701                 b_midlen = 0;
 702
 703         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
 704         if (pfx_length + sfx_length) {
 705                 strbuf_add(&name, a, pfx_length);
 706                 strbuf_addch(&name, '{');
 707         }
 708         strbuf_add(&name, a + pfx_length, a_midlen);
 709         strbuf_addstr(&name, " => ");
 710         strbuf_add(&name, b + pfx_length, b_midlen);
 711         if (pfx_length + sfx_length) {
 712                 strbuf_addch(&name, '}');
 713                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
 714         }
 715         return strbuf_detach(&name, NULL);
 716 }
 717
 718 struct diffstat_t {
 719         int nr;
 720         int alloc;
 721         struct diffstat_file {
 722                 char *from_name;
 723                 char *name;
 724                 char *print_name;
 725                 unsigned is_unmerged:1;
 726                 unsigned is_binary:1;
 727                 unsigned is_renamed:1;
 728                 unsigned int added, deleted;
 729         } **files;
 730 };
 731
 732 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 733                                           const char *name_a,
 734                                           const char *name_b)
 735 {
 736         struct diffstat_file *x;
 737         x = xcalloc(sizeof (*x), 1);
 738         if (diffstat->nr == diffstat->alloc) {
 739                 diffstat->alloc = alloc_nr(diffstat->alloc);
 740                 diffstat->files = xrealloc(diffstat->files,
 741                                 diffstat->alloc * sizeof(x));
 742         }
 743         diffstat->files[diffstat->nr++] = x;
 744         if (name_b) {
 745                 x->from_name = xstrdup(name_a);
 746                 x->name = xstrdup(name_b);
 747                 x->is_renamed = 1;
 748         }
 749         else {
 750                 x->from_name = NULL;
 751                 x->name = xstrdup(name_a);
 752         }
 753         return x;
 754 }
 755
 756 static void diffstat_consume(void *priv, char *line, unsigned long len)
 757 {
 758         struct diffstat_t *diffstat = priv;
 759         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
 760
 761         if (line[0] == '+')
 762                 x->added++;
 763         else if (line[0] == '-')
 764                 x->deleted++;
 765 }
 766
 767 const char mime_boundary_leader[] = "------------";
 768
 769 static int scale_linear(int it, int width, int max_change)
 770 {
 771         /*
 772          * make sure that at least one '-' is printed if there were deletions,
 773          * and likewise for '+'.
 774          */
 775         if (max_change < 2)
 776                 return it;
 777         return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
 778 }
 779
 780 static void show_name(FILE *file,
 781                       const char *prefix, const char *name, int len,
 782                       const char *reset, const char *set)
 783 {
 784         fprintf(file, " %s%s%-*s%s |", set, prefix, len, name, reset);
 785 }
 786
 787 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
 788 {
 789         if (cnt <= 0)
 790                 return;
 791         fprintf(file, "%s", set);
 792         while (cnt--)
 793                 putc(ch, file);
 794         fprintf(file, "%s", reset);
 795 }
 796
 797 static void fill_print_name(struct diffstat_file *file)
 798 {
 799         char *pname;
 800
 801         if (file->print_name)
 802                 return;
 803
 804         if (!file->is_renamed) {
 805                 struct strbuf buf;
 806                 strbuf_init(&buf, 0);
 807                 if (quote_c_style(file->name, &buf, NULL, 0)) {
 808                         pname = strbuf_detach(&buf, NULL);
 809                 } else {
 810                         pname = file->name;
 811                         strbuf_release(&buf);
 812                 }
 813         } else {
 814                 pname = pprint_rename(file->from_name, file->name);
 815         }
 816         file->print_name = pname;
 817 }
 818
 819 static void show_stats(struct diffstat_t* data, struct diff_options *options)
 820 {
 821         int i, len, add, del, total, adds = 0, dels = 0;
 822         int max_change = 0, max_len = 0;
 823         int total_files = data->nr;
 824         int width, name_width;
 825         const char *reset, *set, *add_c, *del_c;
 826
 827         if (data->nr == 0)
 828                 return;
 829
 830         width = options->stat_width ? options->stat_width : 80;
 831         name_width = options->stat_name_width ? options->stat_name_width : 50;
 832
 833         /* Sanity: give at least 5 columns to the graph,
 834          * but leave at least 10 columns for the name.
 835          */
 836         if (width < 25)
 837                 width = 25;
 838         if (name_width < 10)
 839                 name_width = 10;
 840         else if (width < name_width + 15)
 841                 name_width = width - 15;
 842
 843         /* Find the longest filename and max number of changes */
 844         reset = diff_get_color_opt(options, DIFF_RESET);
 845         set   = diff_get_color_opt(options, DIFF_PLAIN);
 846         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
 847         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
 848
 849         for (i = 0; i < data->nr; i++) {
 850                 struct diffstat_file *file = data->files[i];
 851                 int change = file->added + file->deleted;
 852                 fill_print_name(file);
 853                 len = strlen(file->print_name);
 854                 if (max_len < len)
 855                         max_len = len;
 856
 857                 if (file->is_binary || file->is_unmerged)
 858                         continue;
 859                 if (max_change < change)
 860                         max_change = change;
 861         }
 862
 863         /* Compute the width of the graph part;
 864          * 10 is for one blank at the beginning of the line plus
 865          * " | count " between the name and the graph.
 866          *
 867          * From here on, name_width is the width of the name area,
 868          * and width is the width of the graph area.
 869          */
 870         name_width = (name_width < max_len) ? name_width : max_len;
 871         if (width < (name_width + 10) + max_change)
 872                 width = width - (name_width + 10);
 873         else
 874                 width = max_change;
 875
 876         for (i = 0; i < data->nr; i++) {
 877                 const char *prefix = "";
 878                 char *name = data->files[i]->print_name;
 879                 int added = data->files[i]->added;
 880                 int deleted = data->files[i]->deleted;
 881                 int name_len;
 882
 883                 /*
 884                  * "scale" the filename
 885                  */
 886                 len = name_width;
 887                 name_len = strlen(name);
 888                 if (name_width < name_len) {
 889                         char *slash;
 890                         prefix = "...";
 891                         len -= 3;
 892                         name += name_len - len;
 893                         slash = strchr(name, '/');
 894                         if (slash)
 895                                 name = slash;
 896                 }
 897
 898                 if (data->files[i]->is_binary) {
 899                         show_name(options->file, prefix, name, len, reset, set);
 900                         fprintf(options->file, "  Bin ");
 901                         fprintf(options->file, "%s%d%s", del_c, deleted, reset);
 902                         fprintf(options->file, " -> ");
 903                         fprintf(options->file, "%s%d%s", add_c, added, reset);
 904                         fprintf(options->file, " bytes");
 905                         fprintf(options->file, "\n");
 906                         continue;
 907                 }
 908                 else if (data->files[i]->is_unmerged) {
 909                         show_name(options->file, prefix, name, len, reset, set);
 910                         fprintf(options->file, "  Unmerged\n");
 911                         continue;
 912                 }
 913                 else if (!data->files[i]->is_renamed &&
 914                          (added + deleted == 0)) {
 915                         total_files--;
 916                         continue;
 917                 }
 918
 919                 /*
 920                  * scale the add/delete
 921                  */
 922                 add = added;
 923                 del = deleted;
 924                 total = add + del;
 925                 adds += add;
 926                 dels += del;
 927
 928                 if (width <= max_change) {
 929                         add = scale_linear(add, width, max_change);
 930                         del = scale_linear(del, width, max_change);
 931                         total = add + del;
 932                 }
 933                 show_name(options->file, prefix, name, len, reset, set);
 934                 fprintf(options->file, "%5d%s", added + deleted,
 935                                 added + deleted ? " " : "");
 936                 show_graph(options->file, '+', add, add_c, reset);
 937                 show_graph(options->file, '-', del, del_c, reset);
 938                 fprintf(options->file, "\n");
 939         }
 940         fprintf(options->file,
 941                "%s %d files changed, %d insertions(+), %d deletions(-)%s\n",
 942                set, total_files, adds, dels, reset);
 943 }
 944
 945 static void show_shortstats(struct diffstat_t* data, struct diff_options *options)
 946 {
 947         int i, adds = 0, dels = 0, total_files = data->nr;
 948
 949         if (data->nr == 0)
 950                 return;
 951
 952         for (i = 0; i < data->nr; i++) {
 953                 if (!data->files[i]->is_binary &&
 954                     !data->files[i]->is_unmerged) {
 955                         int added = data->files[i]->added;
 956                         int deleted= data->files[i]->deleted;
 957                         if (!data->files[i]->is_renamed &&
 958                             (added + deleted == 0)) {
 959                                 total_files--;
 960                         } else {
 961                                 adds += added;
 962                                 dels += deleted;
 963                         }
 964                 }
 965         }
 966         fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
 967                total_files, adds, dels);
 968 }
 969
 970 static void show_numstat(struct diffstat_t* data, struct diff_options *options)
 971 {
 972         int i;
 973
 974         if (data->nr == 0)
 975                 return;
 976
 977         for (i = 0; i < data->nr; i++) {
 978                 struct diffstat_file *file = data->files[i];
 979
 980                 if (file->is_binary)
 981                         fprintf(options->file, "-\t-\t");
 982                 else
 983                         fprintf(options->file,
 984                                 "%d\t%d\t", file->added, file->deleted);
 985                 if (options->line_termination) {
 986                         fill_print_name(file);
 987                         if (!file->is_renamed)
 988                                 write_name_quoted(file->name, options->file,
 989                                                   options->line_termination);
 990                         else {
 991                                 fputs(file->print_name, options->file);
 992                                 putc(options->line_termination, options->file);
 993                         }
 994                 } else {
 995                         if (file->is_renamed) {
 996                                 putc('\0', options->file);
 997                                 write_name_quoted(file->from_name, options->file, '\0');
 998                         }
 999                         write_name_quoted(file->name, options->file, '\0');
1000                 }
1001         }
1002 }
1003
1004 struct dirstat_file {
1005         const char *name;
1006         unsigned long changed;
1007 };
1008
1009 struct dirstat_dir {
1010         struct dirstat_file *files;
1011         int alloc, nr, percent, cumulative;
1012 };
1013
1014 static long gather_dirstat(FILE *file, struct dirstat_dir *dir, unsigned long changed, const char *base, int baselen)
1015 {
1016         unsigned long this_dir = 0;
1017         unsigned int sources = 0;
1018
1019         while (dir->nr) {
1020                 struct dirstat_file *f = dir->files;
1021                 int namelen = strlen(f->name);
1022                 unsigned long this;
1023                 char *slash;
1024
1025                 if (namelen < baselen)
1026                         break;
1027                 if (memcmp(f->name, base, baselen))
1028                         break;
1029                 slash = strchr(f->name + baselen, '/');
1030                 if (slash) {
1031                         int newbaselen = slash + 1 - f->name;
1032                         this = gather_dirstat(file, dir, changed, f->name, newbaselen);
1033                         sources++;
1034                 } else {
1035                         this = f->changed;
1036                         dir->files++;
1037                         dir->nr--;
1038                         sources += 2;
1039                 }
1040                 this_dir += this;
1041         }
1042
1043         /*
1044          * We don't report dirstat's for
1045          *  - the top level
1046          *  - or cases where everything came from a single directory
1047          *    under this directory (sources == 1).
1048          */
1049         if (baselen && sources != 1) {
1050                 int permille = this_dir * 1000 / changed;
1051                 if (permille) {
1052                         int percent = permille / 10;
1053                         if (percent >= dir->percent) {
1054                                 fprintf(file, "%4d.%01d%% %.*s\n", percent, permille % 10, baselen, base);
1055                                 if (!dir->cumulative)
1056                                         return 0;
1057                         }
1058                 }
1059         }
1060         return this_dir;
1061 }
1062
1063 static int dirstat_compare(const void *_a, const void *_b)
1064 {
1065         const struct dirstat_file *a = _a;
1066         const struct dirstat_file *b = _b;
1067         return strcmp(a->name, b->name);
1068 }
1069
1070 static void show_dirstat(struct diff_options *options)
1071 {
1072         int i;
1073         unsigned long changed;
1074         struct dirstat_dir dir;
1075         struct diff_queue_struct *q = &diff_queued_diff;
1076
1077         dir.files = NULL;
1078         dir.alloc = 0;
1079         dir.nr = 0;
1080         dir.percent = options->dirstat_percent;
1081         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1082
1083         changed = 0;
1084         for (i = 0; i < q->nr; i++) {
1085                 struct diff_filepair *p = q->queue[i];
1086                 const char *name;
1087                 unsigned long copied, added, damage;
1088
1089                 name = p->one->path ? p->one->path : p->two->path;
1090
1091                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1092                         diff_populate_filespec(p->one, 0);
1093                         diff_populate_filespec(p->two, 0);
1094                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1095                                                &copied, &added);
1096                         diff_free_filespec_data(p->one);
1097                         diff_free_filespec_data(p->two);
1098                 } else if (DIFF_FILE_VALID(p->one)) {
1099                         diff_populate_filespec(p->one, 1);
1100                         copied = added = 0;
1101                         diff_free_filespec_data(p->one);
1102                 } else if (DIFF_FILE_VALID(p->two)) {
1103                         diff_populate_filespec(p->two, 1);
1104                         copied = 0;
1105                         added = p->two->size;
1106                         diff_free_filespec_data(p->two);
1107                 } else
1108                         continue;
1109
1110                 /*
1111                  * Original minus copied is the removed material,
1112                  * added is the new material.  They are both damages
1113                  * made to the preimage. In --dirstat-by-file mode, count
1114                  * damaged files, not damaged lines. This is done by
1115                  * counting only a single damaged line per file.
1116                  */
1117                 damage = (p->one->size - copied) + added;
1118                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE) && damage > 0)
1119                         damage = 1;
1120
1121                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1122                 dir.files[dir.nr].name = name;
1123                 dir.files[dir.nr].changed = damage;
1124                 changed += damage;
1125                 dir.nr++;
1126         }
1127
1128         /* This can happen even with many files, if everything was renames */
1129         if (!changed)
1130                 return;
1131
1132         /* Show all directories with more than x% of the changes */
1133         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1134         gather_dirstat(options->file, &dir, changed, "", 0);
1135 }
1136
1137 static void free_diffstat_info(struct diffstat_t *diffstat)
1138 {
1139         int i;
1140         for (i = 0; i < diffstat->nr; i++) {
1141                 struct diffstat_file *f = diffstat->files[i];
1142                 if (f->name != f->print_name)
1143                         free(f->print_name);
1144                 free(f->name);
1145                 free(f->from_name);
1146                 free(f);
1147         }
1148         free(diffstat->files);
1149 }
1150
1151 struct checkdiff_t {
1152         const char *filename;
1153         int lineno;
1154         struct diff_options *o;
1155         unsigned ws_rule;
1156         unsigned status;
1157         int trailing_blanks_start;
1158 };
1159
1160 static int is_conflict_marker(const char *line, unsigned long len)
1161 {
1162         char firstchar;
1163         int cnt;
1164
1165         if (len < 8)
1166                 return 0;
1167         firstchar = line[0];
1168         switch (firstchar) {
1169         case '=': case '>': case '<':
1170                 break;
1171         default:
1172                 return 0;
1173         }
1174         for (cnt = 1; cnt < 7; cnt++)
1175                 if (line[cnt] != firstchar)
1176                         return 0;
1177         /* line[0] thru line[6] are same as firstchar */
1178         if (firstchar == '=') {
1179                 /* divider between ours and theirs? */
1180                 if (len != 8 || line[7] != '\n')
1181                         return 0;
1182         } else if (len < 8 || !isspace(line[7])) {
1183                 /* not divider before ours nor after theirs */
1184                 return 0;
1185         }
1186         return 1;
1187 }
1188
1189 static void checkdiff_consume(void *priv, char *line, unsigned long len)
1190 {
1191         struct checkdiff_t *data = priv;
1192         int color_diff = DIFF_OPT_TST(data->o, COLOR_DIFF);
1193         const char *ws = diff_get_color(color_diff, DIFF_WHITESPACE);
1194         const char *reset = diff_get_color(color_diff, DIFF_RESET);
1195         const char *set = diff_get_color(color_diff, DIFF_FILE_NEW);
1196         char *err;
1197
1198         if (line[0] == '+') {
1199                 unsigned bad;
1200                 data->lineno++;
1201                 if (!ws_blank_line(line + 1, len - 1, data->ws_rule))
1202                         data->trailing_blanks_start = 0;
1203                 else if (!data->trailing_blanks_start)
1204                         data->trailing_blanks_start = data->lineno;
1205                 if (is_conflict_marker(line + 1, len - 1)) {
1206                         data->status |= 1;
1207                         fprintf(data->o->file,
1208                                 "%s:%d: leftover conflict marker\n",
1209                                 data->filename, data->lineno);
1210                 }
1211                 bad = ws_check(line + 1, len - 1, data->ws_rule);
1212                 if (!bad)
1213                         return;
1214                 data->status |= bad;
1215                 err = whitespace_error_string(bad);
1216                 fprintf(data->o->file, "%s:%d: %s.\n",
1217                         data->filename, data->lineno, err);
1218                 free(err);
1219                 emit_line(data->o->file, set, reset, line, 1);
1220                 ws_check_emit(line + 1, len - 1, data->ws_rule,
1221                               data->o->file, set, reset, ws);
1222         } else if (line[0] == ' ') {
1223                 data->lineno++;
1224                 data->trailing_blanks_start = 0;
1225         } else if (line[0] == '@') {
1226                 char *plus = strchr(line, '+');
1227                 if (plus)
1228                         data->lineno = strtol(plus, NULL, 10) - 1;
1229                 else
1230                         die("invalid diff");
1231                 data->trailing_blanks_start = 0;
1232         }
1233 }
1234
1235 static unsigned char *deflate_it(char *data,
1236                                  unsigned long size,
1237                                  unsigned long *result_size)
1238 {
1239         int bound;
1240         unsigned char *deflated;
1241         z_stream stream;
1242
1243         memset(&stream, 0, sizeof(stream));
1244         deflateInit(&stream, zlib_compression_level);
1245         bound = deflateBound(&stream, size);
1246         deflated = xmalloc(bound);
1247         stream.next_out = deflated;
1248         stream.avail_out = bound;
1249
1250         stream.next_in = (unsigned char *)data;
1251         stream.avail_in = size;
1252         while (deflate(&stream, Z_FINISH) == Z_OK)
1253                 ; /* nothing */
1254         deflateEnd(&stream);
1255         *result_size = stream.total_out;
1256         return deflated;
1257 }
1258
1259 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two)
1260 {
1261         void *cp;
1262         void *delta;
1263         void *deflated;
1264         void *data;
1265         unsigned long orig_size;
1266         unsigned long delta_size;
1267         unsigned long deflate_size;
1268         unsigned long data_size;
1269
1270         /* We could do deflated delta, or we could do just deflated two,
1271          * whichever is smaller.
1272          */
1273         delta = NULL;
1274         deflated = deflate_it(two->ptr, two->size, &deflate_size);
1275         if (one->size && two->size) {
1276                 delta = diff_delta(one->ptr, one->size,
1277                                    two->ptr, two->size,
1278                                    &delta_size, deflate_size);
1279                 if (delta) {
1280                         void *to_free = delta;
1281                         orig_size = delta_size;
1282                         delta = deflate_it(delta, delta_size, &delta_size);
1283                         free(to_free);
1284                 }
1285         }
1286
1287         if (delta && delta_size < deflate_size) {
1288                 fprintf(file, "delta %lu\n", orig_size);
1289                 free(deflated);
1290                 data = delta;
1291                 data_size = delta_size;
1292         }
1293         else {
1294                 fprintf(file, "literal %lu\n", two->size);
1295                 free(delta);
1296                 data = deflated;
1297                 data_size = deflate_size;
1298         }
1299
1300         /* emit data encoded in base85 */
1301         cp = data;
1302         while (data_size) {
1303                 int bytes = (52 < data_size) ? 52 : data_size;
1304                 char line[70];
1305                 data_size -= bytes;
1306                 if (bytes <= 26)
1307                         line[0] = bytes + 'A' - 1;
1308                 else
1309                         line[0] = bytes - 26 + 'a' - 1;
1310                 encode_85(line + 1, cp, bytes);
1311                 cp = (char *) cp + bytes;
1312                 fputs(line, file);
1313                 fputc('\n', file);
1314         }
1315         fprintf(file, "\n");
1316         free(data);
1317 }
1318
1319 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two)
1320 {
1321         fprintf(file, "GIT binary patch\n");
1322         emit_binary_diff_body(file, one, two);
1323         emit_binary_diff_body(file, two, one);
1324 }
1325
1326 static void setup_diff_attr_check(struct git_attr_check *check)
1327 {
1328         static struct git_attr *attr_diff;
1329
1330         if (!attr_diff) {
1331                 attr_diff = git_attr("diff", 4);
1332         }
1333         check[0].attr = attr_diff;
1334 }
1335
1336 static void diff_filespec_check_attr(struct diff_filespec *one)
1337 {
1338         struct git_attr_check attr_diff_check;
1339         int check_from_data = 0;
1340
1341         if (one->checked_attr)
1342                 return;
1343
1344         setup_diff_attr_check(&attr_diff_check);
1345         one->is_binary = 0;
1346         one->funcname_pattern_ident = NULL;
1347
1348         if (!git_checkattr(one->path, 1, &attr_diff_check)) {
1349                 const char *value;
1350
1351                 /* binaryness */
1352                 value = attr_diff_check.value;
1353                 if (ATTR_TRUE(value))
1354                         ;
1355                 else if (ATTR_FALSE(value))
1356                         one->is_binary = 1;
1357                 else
1358                         check_from_data = 1;
1359
1360                 /* funcname pattern ident */
1361                 if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
1362                         ;
1363                 else
1364                         one->funcname_pattern_ident = value;
1365         }
1366
1367         if (check_from_data) {
1368                 if (!one->data && DIFF_FILE_VALID(one))
1369                         diff_populate_filespec(one, 0);
1370
1371                 if (one->data)
1372                         one->is_binary = buffer_is_binary(one->data, one->size);
1373         }
1374 }
1375
1376 int diff_filespec_is_binary(struct diff_filespec *one)
1377 {
1378         diff_filespec_check_attr(one);
1379         return one->is_binary;
1380 }
1381
1382 static const char *funcname_pattern(const char *ident)
1383 {
1384         struct funcname_pattern *pp;
1385
1386         for (pp = funcname_pattern_list; pp; pp = pp->next)
1387                 if (!strcmp(ident, pp->name))
1388                         return pp->pattern;
1389         return NULL;
1390 }
1391
1392 static struct builtin_funcname_pattern {
1393         const char *name;
1394         const char *pattern;
1395 } builtin_funcname_pattern[] = {
1396         { "bibtex", "\\(@[a-zA-Z]\\{1,\\}[ \t]*{\\{0,1\\}[ \t]*[^ \t\"@',\\#}{~%]*\\).*$" },
1397         { "html", "^\\s*\\(<[Hh][1-6]\\s.*>.*\\)$" },
1398         { "java", "!^[  ]*\\(catch\\|do\\|for\\|if\\|instanceof\\|"
1399                         "new\\|return\\|switch\\|throw\\|while\\)\n"
1400                         "^[     ]*\\(\\([       ]*"
1401                         "[A-Za-z_][A-Za-z_0-9]*\\)\\{2,\\}"
1402                         "[      ]*([^;]*\\)$" },
1403         { "pascal", "^\\(\\(procedure\\|function\\|constructor\\|"
1404                         "destructor\\|interface\\|implementation\\|"
1405                         "initialization\\|finalization\\)[ \t]*.*\\)$"
1406                         "\\|"
1407                         "^\\(.*=[ \t]*\\(class\\|record\\).*\\)$"
1408                         },
1409         { "python", "^\\s*\\(\\(class\\|def\\)\\s.*\\)$" },
1410         { "ruby", "^\\s*\\(\\(class\\|module\\|def\\)\\s.*\\)$" },
1411         { "tex", "^\\(\\\\\\(\\(sub\\)*section\\|chapter\\|part\\)\\*\\{0,1\\}{.*\\)$" },
1412 };
1413
1414 static const char *diff_funcname_pattern(struct diff_filespec *one)
1415 {
1416         const char *ident, *pattern;
1417         int i;
1418
1419         diff_filespec_check_attr(one);
1420         ident = one->funcname_pattern_ident;
1421
1422         if (!ident)
1423                 /*
1424                  * If the config file has "funcname.default" defined, that
1425                  * regexp is used; otherwise NULL is returned and xemit uses
1426                  * the built-in default.
1427                  */
1428                 return funcname_pattern("default");
1429
1430         /* Look up custom "funcname.$ident" regexp from config. */
1431         pattern = funcname_pattern(ident);
1432         if (pattern)
1433                 return pattern;
1434
1435         /*
1436          * And define built-in fallback patterns here.  Note that
1437          * these can be overridden by the user's config settings.
1438          */
1439         for (i = 0; i < ARRAY_SIZE(builtin_funcname_pattern); i++)
1440                 if (!strcmp(ident, builtin_funcname_pattern[i].name))
1441                         return builtin_funcname_pattern[i].pattern;
1442
1443         return NULL;
1444 }
1445
1446 static void builtin_diff(const char *name_a,
1447                          const char *name_b,
1448                          struct diff_filespec *one,
1449                          struct diff_filespec *two,
1450                          const char *xfrm_msg,
1451                          struct diff_options *o,
1452                          int complete_rewrite)
1453 {
1454         mmfile_t mf1, mf2;
1455         const char *lbl[2];
1456         char *a_one, *b_two;
1457         const char *set = diff_get_color_opt(o, DIFF_METAINFO);
1458         const char *reset = diff_get_color_opt(o, DIFF_RESET);
1459
1460         a_one = quote_two(o->a_prefix, name_a + (*name_a == '/'));
1461         b_two = quote_two(o->b_prefix, name_b + (*name_b == '/'));
1462         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
1463         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
1464         fprintf(o->file, "%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
1465         if (lbl[0][0] == '/') {
1466                 /* /dev/null */
1467                 fprintf(o->file, "%snew file mode %06o%s\n", set, two->mode, reset);
1468                 if (xfrm_msg && xfrm_msg[0])
1469                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1470         }
1471         else if (lbl[1][0] == '/') {
1472                 fprintf(o->file, "%sdeleted file mode %06o%s\n", set, one->mode, reset);
1473                 if (xfrm_msg && xfrm_msg[0])
1474                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1475         }
1476         else {
1477                 if (one->mode != two->mode) {
1478                         fprintf(o->file, "%sold mode %06o%s\n", set, one->mode, reset);
1479                         fprintf(o->file, "%snew mode %06o%s\n", set, two->mode, reset);
1480                 }
1481                 if (xfrm_msg && xfrm_msg[0])
1482                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1483                 /*
1484                  * we do not run diff between different kind
1485                  * of objects.
1486                  */
1487                 if ((one->mode ^ two->mode) & S_IFMT)
1488                         goto free_ab_and_return;
1489                 if (complete_rewrite) {
1490                         emit_rewrite_diff(name_a, name_b, one, two, o);
1491                         o->found_changes = 1;
1492                         goto free_ab_and_return;
1493                 }
1494         }
1495
1496         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1497                 die("unable to read files to diff");
1498
1499         if (!DIFF_OPT_TST(o, TEXT) &&
1500             (diff_filespec_is_binary(one) || diff_filespec_is_binary(two))) {
1501                 /* Quite common confusing case */
1502                 if (mf1.size == mf2.size &&
1503                     !memcmp(mf1.ptr, mf2.ptr, mf1.size))
1504                         goto free_ab_and_return;
1505                 if (DIFF_OPT_TST(o, BINARY))
1506                         emit_binary_diff(o->file, &mf1, &mf2);
1507                 else
1508                         fprintf(o->file, "Binary files %s and %s differ\n",
1509                                 lbl[0], lbl[1]);
1510                 o->found_changes = 1;
1511         }
1512         else {
1513                 /* Crazy xdl interfaces.. */
1514                 const char *diffopts = getenv("GIT_DIFF_OPTS");
1515                 xpparam_t xpp;
1516                 xdemitconf_t xecfg;
1517                 xdemitcb_t ecb;
1518                 struct emit_callback ecbdata;
1519                 const char *funcname_pattern;
1520
1521                 funcname_pattern = diff_funcname_pattern(one);
1522                 if (!funcname_pattern)
1523                         funcname_pattern = diff_funcname_pattern(two);
1524
1525                 memset(&xecfg, 0, sizeof(xecfg));
1526                 memset(&ecbdata, 0, sizeof(ecbdata));
1527                 ecbdata.label_path = lbl;
1528                 ecbdata.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
1529                 ecbdata.found_changesp = &o->found_changes;
1530                 ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
1531                 ecbdata.file = o->file;
1532                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1533                 xecfg.ctxlen = o->context;
1534                 xecfg.flags = XDL_EMIT_FUNCNAMES;
1535                 if (funcname_pattern)
1536                         xdiff_set_find_func(&xecfg, funcname_pattern);
1537                 if (!diffopts)
1538                         ;
1539                 else if (!prefixcmp(diffopts, "--unified="))
1540                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
1541                 else if (!prefixcmp(diffopts, "-u"))
1542                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
1543                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS)) {
1544                         ecbdata.diff_words =
1545                                 xcalloc(1, sizeof(struct diff_words_data));
1546                         ecbdata.diff_words->file = o->file;
1547                 }
1548                 xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
1549                               &xpp, &xecfg, &ecb);
1550                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS))
1551                         free_diff_words_data(&ecbdata);
1552         }
1553
1554  free_ab_and_return:
1555         diff_free_filespec_data(one);
1556         diff_free_filespec_data(two);
1557         free(a_one);
1558         free(b_two);
1559         return;
1560 }
1561
1562 static void builtin_diffstat(const char *name_a, const char *name_b,
1563                              struct diff_filespec *one,
1564                              struct diff_filespec *two,
1565                              struct diffstat_t *diffstat,
1566                              struct diff_options *o,
1567                              int complete_rewrite)
1568 {
1569         mmfile_t mf1, mf2;
1570         struct diffstat_file *data;
1571
1572         data = diffstat_add(diffstat, name_a, name_b);
1573
1574         if (!one || !two) {
1575                 data->is_unmerged = 1;
1576                 return;
1577         }
1578         if (complete_rewrite) {
1579                 diff_populate_filespec(one, 0);
1580                 diff_populate_filespec(two, 0);
1581                 data->deleted = count_lines(one->data, one->size);
1582                 data->added = count_lines(two->data, two->size);
1583                 goto free_and_return;
1584         }
1585         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1586                 die("unable to read files to diff");
1587
1588         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
1589                 data->is_binary = 1;
1590                 data->added = mf2.size;
1591                 data->deleted = mf1.size;
1592         } else {
1593                 /* Crazy xdl interfaces.. */
1594                 xpparam_t xpp;
1595                 xdemitconf_t xecfg;
1596                 xdemitcb_t ecb;
1597
1598                 memset(&xecfg, 0, sizeof(xecfg));
1599                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1600                 xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
1601                               &xpp, &xecfg, &ecb);
1602         }
1603
1604  free_and_return:
1605         diff_free_filespec_data(one);
1606         diff_free_filespec_data(two);
1607 }
1608
1609 static void builtin_checkdiff(const char *name_a, const char *name_b,
1610                               const char *attr_path,
1611                               struct diff_filespec *one,
1612                               struct diff_filespec *two,
1613                               struct diff_options *o)
1614 {
1615         mmfile_t mf1, mf2;
1616         struct checkdiff_t data;
1617
1618         if (!two)
1619                 return;
1620
1621         memset(&data, 0, sizeof(data));
1622         data.filename = name_b ? name_b : name_a;
1623         data.lineno = 0;
1624         data.o = o;
1625         data.ws_rule = whitespace_rule(attr_path);
1626
1627         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1628                 die("unable to read files to diff");
1629
1630         /*
1631          * All the other codepaths check both sides, but not checking
1632          * the "old" side here is deliberate.  We are checking the newly
1633          * introduced changes, and as long as the "new" side is text, we
1634          * can and should check what it introduces.
1635          */
1636         if (diff_filespec_is_binary(two))
1637                 goto free_and_return;
1638         else {
1639                 /* Crazy xdl interfaces.. */
1640                 xpparam_t xpp;
1641                 xdemitconf_t xecfg;
1642                 xdemitcb_t ecb;
1643
1644                 memset(&xecfg, 0, sizeof(xecfg));
1645                 xecfg.ctxlen = 1; /* at least one context line */
1646                 xpp.flags = XDF_NEED_MINIMAL;
1647                 xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
1648                               &xpp, &xecfg, &ecb);
1649
1650                 if ((data.ws_rule & WS_TRAILING_SPACE) &&
1651                     data.trailing_blanks_start) {
1652                         fprintf(o->file, "%s:%d: ends with blank lines.\n",
1653                                 data.filename, data.trailing_blanks_start);
1654                         data.status = 1; /* report errors */
1655                 }
1656         }
1657  free_and_return:
1658         diff_free_filespec_data(one);
1659         diff_free_filespec_data(two);
1660         if (data.status)
1661                 DIFF_OPT_SET(o, CHECK_FAILED);
1662 }
1663
1664 struct diff_filespec *alloc_filespec(const char *path)
1665 {
1666         int namelen = strlen(path);
1667         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
1668
1669         memset(spec, 0, sizeof(*spec));
1670         spec->path = (char *)(spec + 1);
1671         memcpy(spec->path, path, namelen+1);
1672         spec->count = 1;
1673         return spec;
1674 }
1675
1676 void free_filespec(struct diff_filespec *spec)
1677 {
1678         if (!--spec->count) {
1679                 diff_free_filespec_data(spec);
1680                 free(spec);
1681         }
1682 }
1683
1684 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
1685                    unsigned short mode)
1686 {
1687         if (mode) {
1688                 spec->mode = canon_mode(mode);
1689                 hashcpy(spec->sha1, sha1);
1690                 spec->sha1_valid = !is_null_sha1(sha1);
1691         }
1692 }
1693
1694 /*
1695  * Given a name and sha1 pair, if the index tells us the file in
1696  * the work tree has that object contents, return true, so that
1697  * prepare_temp_file() does not have to inflate and extract.
1698  */
1699 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
1700 {
1701         struct cache_entry *ce;
1702         struct stat st;
1703         int pos, len;
1704
1705         /* We do not read the cache ourselves here, because the
1706          * benchmark with my previous version that always reads cache
1707          * shows that it makes things worse for diff-tree comparing
1708          * two linux-2.6 kernel trees in an already checked out work
1709          * tree.  This is because most diff-tree comparisons deal with
1710          * only a small number of files, while reading the cache is
1711          * expensive for a large project, and its cost outweighs the
1712          * savings we get by not inflating the object to a temporary
1713          * file.  Practically, this code only helps when we are used
1714          * by diff-cache --cached, which does read the cache before
1715          * calling us.
1716          */
1717         if (!active_cache)
1718                 return 0;
1719
1720         /* We want to avoid the working directory if our caller
1721          * doesn't need the data in a normal file, this system
1722          * is rather slow with its stat/open/mmap/close syscalls,
1723          * and the object is contained in a pack file.  The pack
1724          * is probably already open and will be faster to obtain
1725          * the data through than the working directory.  Loose
1726          * objects however would tend to be slower as they need
1727          * to be individually opened and inflated.
1728          */
1729         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1, NULL))
1730                 return 0;
1731
1732         len = strlen(name);
1733         pos = cache_name_pos(name, len);
1734         if (pos < 0)
1735                 return 0;
1736         ce = active_cache[pos];
1737
1738         /*
1739          * This is not the sha1 we are looking for, or
1740          * unreusable because it is not a regular file.
1741          */
1742         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
1743                 return 0;
1744
1745         /*
1746          * If ce matches the file in the work tree, we can reuse it.
1747          */
1748         if (ce_uptodate(ce) ||
1749             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
1750                 return 1;
1751
1752         return 0;
1753 }
1754
1755 static int populate_from_stdin(struct diff_filespec *s)
1756 {
1757         struct strbuf buf;
1758         size_t size = 0;
1759
1760         strbuf_init(&buf, 0);
1761         if (strbuf_read(&buf, 0, 0) < 0)
1762                 return error("error while reading from stdin %s",
1763                                      strerror(errno));
1764
1765         s->should_munmap = 0;
1766         s->data = strbuf_detach(&buf, &size);
1767         s->size = size;
1768         s->should_free = 1;
1769         return 0;
1770 }
1771
1772 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
1773 {
1774         int len;
1775         char *data = xmalloc(100);
1776         len = snprintf(data, 100,
1777                 "Subproject commit %s\n", sha1_to_hex(s->sha1));
1778         s->data = data;
1779         s->size = len;
1780         s->should_free = 1;
1781         if (size_only) {
1782                 s->data = NULL;
1783                 free(data);
1784         }
1785         return 0;
1786 }
1787
1788 /*
1789  * While doing rename detection and pickaxe operation, we may need to
1790  * grab the data for the blob (or file) for our own in-core comparison.
1791  * diff_filespec has data and size fields for this purpose.
1792  */
1793 int diff_populate_filespec(struct diff_filespec *s, int size_only)
1794 {
1795         int err = 0;
1796         if (!DIFF_FILE_VALID(s))
1797                 die("internal error: asking to populate invalid file.");
1798         if (S_ISDIR(s->mode))
1799                 return -1;
1800
1801         if (s->data)
1802                 return 0;
1803
1804         if (size_only && 0 < s->size)
1805                 return 0;
1806
1807         if (S_ISGITLINK(s->mode))
1808                 return diff_populate_gitlink(s, size_only);
1809
1810         if (!s->sha1_valid ||
1811             reuse_worktree_file(s->path, s->sha1, 0)) {
1812                 struct strbuf buf;
1813                 struct stat st;
1814                 int fd;
1815
1816                 if (!strcmp(s->path, "-"))
1817                         return populate_from_stdin(s);
1818
1819                 if (lstat(s->path, &st) < 0) {
1820                         if (errno == ENOENT) {
1821                         err_empty:
1822                                 err = -1;
1823                         empty:
1824                                 s->data = (char *)"";
1825                                 s->size = 0;
1826                                 return err;
1827                         }
1828                 }
1829                 s->size = xsize_t(st.st_size);
1830                 if (!s->size)
1831                         goto empty;
1832                 if (size_only)
1833                         return 0;
1834                 if (S_ISLNK(st.st_mode)) {
1835                         int ret;
1836                         s->data = xmalloc(s->size);
1837                         s->should_free = 1;
1838                         ret = readlink(s->path, s->data, s->size);
1839                         if (ret < 0) {
1840                                 free(s->data);
1841                                 goto err_empty;
1842                         }
1843                         return 0;
1844                 }
1845                 fd = open(s->path, O_RDONLY);
1846                 if (fd < 0)
1847                         goto err_empty;
1848                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
1849                 close(fd);
1850                 s->should_munmap = 1;
1851
1852                 /*
1853                  * Convert from working tree format to canonical git format
1854                  */
1855                 strbuf_init(&buf, 0);
1856                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
1857                         size_t size = 0;
1858                         munmap(s->data, s->size);
1859                         s->should_munmap = 0;
1860                         s->data = strbuf_detach(&buf, &size);
1861                         s->size = size;
1862                         s->should_free = 1;
1863                 }
1864         }
1865         else {
1866                 enum object_type type;
1867                 if (size_only)
1868                         type = sha1_object_info(s->sha1, &s->size);
1869                 else {
1870                         s->data = read_sha1_file(s->sha1, &type, &s->size);
1871                         s->should_free = 1;
1872                 }
1873         }
1874         return 0;
1875 }
1876
1877 void diff_free_filespec_blob(struct diff_filespec *s)
1878 {
1879         if (s->should_free)
1880                 free(s->data);
1881         else if (s->should_munmap)
1882                 munmap(s->data, s->size);
1883
1884         if (s->should_free || s->should_munmap) {
1885                 s->should_free = s->should_munmap = 0;
1886                 s->data = NULL;
1887         }
1888 }
1889
1890 void diff_free_filespec_data(struct diff_filespec *s)
1891 {
1892         diff_free_filespec_blob(s);
1893         free(s->cnt_data);
1894         s->cnt_data = NULL;
1895 }
1896
1897 static void prep_temp_blob(struct diff_tempfile *temp,
1898                            void *blob,
1899                            unsigned long size,
1900                            const unsigned char *sha1,
1901                            int mode)
1902 {
1903         int fd;
1904
1905         fd = git_mkstemp(temp->tmp_path, PATH_MAX, ".diff_XXXXXX");
1906         if (fd < 0)
1907                 die("unable to create temp-file: %s", strerror(errno));
1908         if (write_in_full(fd, blob, size) != size)
1909                 die("unable to write temp-file");
1910         close(fd);
1911         temp->name = temp->tmp_path;
1912         strcpy(temp->hex, sha1_to_hex(sha1));
1913         temp->hex[40] = 0;
1914         sprintf(temp->mode, "%06o", mode);
1915 }
1916
1917 static void prepare_temp_file(const char *name,
1918                               struct diff_tempfile *temp,
1919                               struct diff_filespec *one)
1920 {
1921         if (!DIFF_FILE_VALID(one)) {
1922         not_a_valid_file:
1923                 /* A '-' entry produces this for file-2, and
1924                  * a '+' entry produces this for file-1.
1925                  */
1926                 temp->name = "/dev/null";
1927                 strcpy(temp->hex, ".");
1928                 strcpy(temp->mode, ".");
1929                 return;
1930         }
1931
1932         if (!one->sha1_valid ||
1933             reuse_worktree_file(name, one->sha1, 1)) {
1934                 struct stat st;
1935                 if (lstat(name, &st) < 0) {
1936                         if (errno == ENOENT)
1937                                 goto not_a_valid_file;
1938                         die("stat(%s): %s", name, strerror(errno));
1939                 }
1940                 if (S_ISLNK(st.st_mode)) {
1941                         int ret;
1942                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
1943                         size_t sz = xsize_t(st.st_size);
1944                         if (sizeof(buf) <= st.st_size)
1945                                 die("symlink too long: %s", name);
1946                         ret = readlink(name, buf, sz);
1947                         if (ret < 0)
1948                                 die("readlink(%s)", name);
1949                         prep_temp_blob(temp, buf, sz,
1950                                        (one->sha1_valid ?
1951                                         one->sha1 : null_sha1),
1952                                        (one->sha1_valid ?
1953                                         one->mode : S_IFLNK));
1954                 }
1955                 else {
1956                         /* we can borrow from the file in the work tree */
1957                         temp->name = name;
1958                         if (!one->sha1_valid)
1959                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
1960                         else
1961                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
1962                         /* Even though we may sometimes borrow the
1963                          * contents from the work tree, we always want
1964                          * one->mode.  mode is trustworthy even when
1965                          * !(one->sha1_valid), as long as
1966                          * DIFF_FILE_VALID(one).
1967                          */
1968                         sprintf(temp->mode, "%06o", one->mode);
1969                 }
1970                 return;
1971         }
1972         else {
1973                 if (diff_populate_filespec(one, 0))
1974                         die("cannot read data blob for %s", one->path);
1975                 prep_temp_blob(temp, one->data, one->size,
1976                                one->sha1, one->mode);
1977         }
1978 }
1979
1980 static void remove_tempfile(void)
1981 {
1982         int i;
1983
1984         for (i = 0; i < 2; i++)
1985                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
1986                         unlink(diff_temp[i].name);
1987                         diff_temp[i].name = NULL;
1988                 }
1989 }
1990
1991 static void remove_tempfile_on_signal(int signo)
1992 {
1993         remove_tempfile();
1994         signal(SIGINT, SIG_DFL);
1995         raise(signo);
1996 }
1997
1998 /* An external diff command takes:
1999  *
2000  * diff-cmd name infile1 infile1-sha1 infile1-mode \
2001  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2002  *
2003  */
2004 static void run_external_diff(const char *pgm,
2005                               const char *name,
2006                               const char *other,
2007                               struct diff_filespec *one,
2008                               struct diff_filespec *two,
2009                               const char *xfrm_msg,
2010                               int complete_rewrite)
2011 {
2012         const char *spawn_arg[10];
2013         struct diff_tempfile *temp = diff_temp;
2014         int retval;
2015         static int atexit_asked = 0;
2016         const char *othername;
2017         const char **arg = &spawn_arg[0];
2018
2019         othername = (other? other : name);
2020         if (one && two) {
2021                 prepare_temp_file(name, &temp[0], one);
2022                 prepare_temp_file(othername, &temp[1], two);
2023                 if (! atexit_asked &&
2024                     (temp[0].name == temp[0].tmp_path ||
2025                      temp[1].name == temp[1].tmp_path)) {
2026                         atexit_asked = 1;
2027                         atexit(remove_tempfile);
2028                 }
2029                 signal(SIGINT, remove_tempfile_on_signal);
2030         }
2031
2032         if (one && two) {
2033                 *arg++ = pgm;
2034                 *arg++ = name;
2035                 *arg++ = temp[0].name;
2036                 *arg++ = temp[0].hex;
2037                 *arg++ = temp[0].mode;
2038                 *arg++ = temp[1].name;
2039                 *arg++ = temp[1].hex;
2040                 *arg++ = temp[1].mode;
2041                 if (other) {
2042                         *arg++ = other;
2043                         *arg++ = xfrm_msg;
2044                 }
2045         } else {
2046                 *arg++ = pgm;
2047                 *arg++ = name;
2048         }
2049         *arg = NULL;
2050         fflush(NULL);
2051         retval = run_command_v_opt(spawn_arg, 0);
2052         remove_tempfile();
2053         if (retval) {
2054                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
2055                 exit(1);
2056         }
2057 }
2058
2059 static const char *external_diff_attr(const char *name)
2060 {
2061         struct git_attr_check attr_diff_check;
2062
2063         if (!name)
2064                 return NULL;
2065
2066         setup_diff_attr_check(&attr_diff_check);
2067         if (!git_checkattr(name, 1, &attr_diff_check)) {
2068                 const char *value = attr_diff_check.value;
2069                 if (!ATTR_TRUE(value) &&
2070                     !ATTR_FALSE(value) &&
2071                     !ATTR_UNSET(value)) {
2072                         struct ll_diff_driver *drv;
2073
2074                         for (drv = user_diff; drv; drv = drv->next)
2075                                 if (!strcmp(drv->name, value))
2076                                         return drv->cmd;
2077                 }
2078         }
2079         return NULL;
2080 }
2081
2082 static void run_diff_cmd(const char *pgm,
2083                          const char *name,
2084                          const char *other,
2085                          const char *attr_path,
2086                          struct diff_filespec *one,
2087                          struct diff_filespec *two,
2088                          const char *xfrm_msg,
2089                          struct diff_options *o,
2090                          int complete_rewrite)
2091 {
2092         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
2093                 pgm = NULL;
2094         else {
2095                 const char *cmd = external_diff_attr(attr_path);
2096                 if (cmd)
2097                         pgm = cmd;
2098         }
2099
2100         if (pgm) {
2101                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
2102                                   complete_rewrite);
2103                 return;
2104         }
2105         if (one && two)
2106                 builtin_diff(name, other ? other : name,
2107                              one, two, xfrm_msg, o, complete_rewrite);
2108         else
2109                 fprintf(o->file, "* Unmerged path %s\n", name);
2110 }
2111
2112 static void diff_fill_sha1_info(struct diff_filespec *one)
2113 {
2114         if (DIFF_FILE_VALID(one)) {
2115                 if (!one->sha1_valid) {
2116                         struct stat st;
2117                         if (!strcmp(one->path, "-")) {
2118                                 hashcpy(one->sha1, null_sha1);
2119                                 return;
2120                         }
2121                         if (lstat(one->path, &st) < 0)
2122                                 die("stat %s", one->path);
2123                         if (index_path(one->sha1, one->path, &st, 0))
2124                                 die("cannot hash %s\n", one->path);
2125                 }
2126         }
2127         else
2128                 hashclr(one->sha1);
2129 }
2130
2131 static int similarity_index(struct diff_filepair *p)
2132 {
2133         return p->score * 100 / MAX_SCORE;
2134 }
2135
2136 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2137 {
2138         /* Strip the prefix but do not molest /dev/null and absolute paths */
2139         if (*namep && **namep != '/')
2140                 *namep += prefix_length;
2141         if (*otherp && **otherp != '/')
2142                 *otherp += prefix_length;
2143 }
2144
2145 static void run_diff(struct diff_filepair *p, struct diff_options *o)
2146 {
2147         const char *pgm = external_diff();
2148         struct strbuf msg;
2149         char *xfrm_msg;
2150         struct diff_filespec *one = p->one;
2151         struct diff_filespec *two = p->two;
2152         const char *name;
2153         const char *other;
2154         const char *attr_path;
2155         int complete_rewrite = 0;
2156
2157         name  = p->one->path;
2158         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2159         attr_path = name;
2160         if (o->prefix_length)
2161                 strip_prefix(o->prefix_length, &name, &other);
2162
2163         if (DIFF_PAIR_UNMERGED(p)) {
2164                 run_diff_cmd(pgm, name, NULL, attr_path,
2165                              NULL, NULL, NULL, o, 0);
2166                 return;
2167         }
2168
2169         diff_fill_sha1_info(one);
2170         diff_fill_sha1_info(two);
2171
2172         strbuf_init(&msg, PATH_MAX * 2 + 300);
2173         switch (p->status) {
2174         case DIFF_STATUS_COPIED:
2175                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2176                 strbuf_addstr(&msg, "\ncopy from ");
2177                 quote_c_style(name, &msg, NULL, 0);
2178                 strbuf_addstr(&msg, "\ncopy to ");
2179                 quote_c_style(other, &msg, NULL, 0);
2180                 strbuf_addch(&msg, '\n');
2181                 break;
2182         case DIFF_STATUS_RENAMED:
2183                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2184                 strbuf_addstr(&msg, "\nrename from ");
2185                 quote_c_style(name, &msg, NULL, 0);
2186                 strbuf_addstr(&msg, "\nrename to ");
2187                 quote_c_style(other, &msg, NULL, 0);
2188                 strbuf_addch(&msg, '\n');
2189                 break;
2190         case DIFF_STATUS_MODIFIED:
2191                 if (p->score) {
2192                         strbuf_addf(&msg, "dissimilarity index %d%%\n",
2193                                         similarity_index(p));
2194                         complete_rewrite = 1;
2195                         break;
2196                 }
2197                 /* fallthru */
2198         default:
2199                 /* nothing */
2200                 ;
2201         }
2202
2203         if (hashcmp(one->sha1, two->sha1)) {
2204                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2205
2206                 if (DIFF_OPT_TST(o, BINARY)) {
2207                         mmfile_t mf;
2208                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2209                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2210                                 abbrev = 40;
2211                 }
2212                 strbuf_addf(&msg, "index %.*s..%.*s",
2213                                 abbrev, sha1_to_hex(one->sha1),
2214                                 abbrev, sha1_to_hex(two->sha1));
2215                 if (one->mode == two->mode)
2216                         strbuf_addf(&msg, " %06o", one->mode);
2217                 strbuf_addch(&msg, '\n');
2218         }
2219
2220         if (msg.len)
2221                 strbuf_setlen(&msg, msg.len - 1);
2222         xfrm_msg = msg.len ? msg.buf : NULL;
2223
2224         if (!pgm &&
2225             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
2226             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
2227                 /* a filepair that changes between file and symlink
2228                  * needs to be split into deletion and creation.
2229                  */
2230                 struct diff_filespec *null = alloc_filespec(two->path);
2231                 run_diff_cmd(NULL, name, other, attr_path,
2232                              one, null, xfrm_msg, o, 0);
2233                 free(null);
2234                 null = alloc_filespec(one->path);
2235                 run_diff_cmd(NULL, name, other, attr_path,
2236                              null, two, xfrm_msg, o, 0);
2237                 free(null);
2238         }
2239         else
2240                 run_diff_cmd(pgm, name, other, attr_path,
2241                              one, two, xfrm_msg, o, complete_rewrite);
2242
2243         strbuf_release(&msg);
2244 }
2245
2246 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
2247                          struct diffstat_t *diffstat)
2248 {
2249         const char *name;
2250         const char *other;
2251         int complete_rewrite = 0;
2252
2253         if (DIFF_PAIR_UNMERGED(p)) {
2254                 /* unmerged */
2255                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
2256                 return;
2257         }
2258
2259         name = p->one->path;
2260         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2261
2262         if (o->prefix_length)
2263                 strip_prefix(o->prefix_length, &name, &other);
2264
2265         diff_fill_sha1_info(p->one);
2266         diff_fill_sha1_info(p->two);
2267
2268         if (p->status == DIFF_STATUS_MODIFIED && p->score)
2269                 complete_rewrite = 1;
2270         builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
2271 }
2272
2273 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
2274 {
2275         const char *name;
2276         const char *other;
2277         const char *attr_path;
2278
2279         if (DIFF_PAIR_UNMERGED(p)) {
2280                 /* unmerged */
2281                 return;
2282         }
2283
2284         name = p->one->path;
2285         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2286         attr_path = other ? other : name;
2287
2288         if (o->prefix_length)
2289                 strip_prefix(o->prefix_length, &name, &other);
2290
2291         diff_fill_sha1_info(p->one);
2292         diff_fill_sha1_info(p->two);
2293
2294         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
2295 }
2296
2297 void diff_setup(struct diff_options *options)
2298 {
2299         memset(options, 0, sizeof(*options));
2300
2301         options->file = stdout;
2302
2303         options->line_termination = '\n';
2304         options->break_opt = -1;
2305         options->rename_limit = -1;
2306         options->dirstat_percent = 3;
2307         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
2308         options->context = 3;
2309
2310         options->change = diff_change;
2311         options->add_remove = diff_addremove;
2312         if (diff_use_color_default > 0)
2313                 DIFF_OPT_SET(options, COLOR_DIFF);
2314         else
2315                 DIFF_OPT_CLR(options, COLOR_DIFF);
2316         options->detect_rename = diff_detect_rename_default;
2317
2318         options->a_prefix = "a/";
2319         options->b_prefix = "b/";
2320 }
2321
2322 int diff_setup_done(struct diff_options *options)
2323 {
2324         int count = 0;
2325
2326         if (options->output_format & DIFF_FORMAT_NAME)
2327                 count++;
2328         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
2329                 count++;
2330         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
2331                 count++;
2332         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
2333                 count++;
2334         if (count > 1)
2335                 die("--name-only, --name-status, --check and -s are mutually exclusive");
2336
2337         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
2338                 options->detect_rename = DIFF_DETECT_COPY;
2339
2340         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
2341                 options->prefix = NULL;
2342         if (options->prefix)
2343                 options->prefix_length = strlen(options->prefix);
2344         else
2345                 options->prefix_length = 0;
2346
2347         if (options->output_format & (DIFF_FORMAT_NAME |
2348                                       DIFF_FORMAT_NAME_STATUS |
2349                                       DIFF_FORMAT_CHECKDIFF |
2350                                       DIFF_FORMAT_NO_OUTPUT))
2351                 options->output_format &= ~(DIFF_FORMAT_RAW |
2352                                             DIFF_FORMAT_NUMSTAT |
2353                                             DIFF_FORMAT_DIFFSTAT |
2354                                             DIFF_FORMAT_SHORTSTAT |
2355                                             DIFF_FORMAT_DIRSTAT |
2356                                             DIFF_FORMAT_SUMMARY |
2357                                             DIFF_FORMAT_PATCH);
2358
2359         /*
2360          * These cases always need recursive; we do not drop caller-supplied
2361          * recursive bits for other formats here.
2362          */
2363         if (options->output_format & (DIFF_FORMAT_PATCH |
2364                                       DIFF_FORMAT_NUMSTAT |
2365                                       DIFF_FORMAT_DIFFSTAT |
2366                                       DIFF_FORMAT_SHORTSTAT |
2367                                       DIFF_FORMAT_DIRSTAT |
2368                                       DIFF_FORMAT_SUMMARY |
2369                                       DIFF_FORMAT_CHECKDIFF))
2370                 DIFF_OPT_SET(options, RECURSIVE);
2371         /*
2372          * Also pickaxe would not work very well if you do not say recursive
2373          */
2374         if (options->pickaxe)
2375                 DIFF_OPT_SET(options, RECURSIVE);
2376
2377         if (options->detect_rename && options->rename_limit < 0)
2378                 options->rename_limit = diff_rename_limit_default;
2379         if (options->setup & DIFF_SETUP_USE_CACHE) {
2380                 if (!active_cache)
2381                         /* read-cache does not die even when it fails
2382                          * so it is safe for us to do this here.  Also
2383                          * it does not smudge active_cache or active_nr
2384                          * when it fails, so we do not have to worry about
2385                          * cleaning it up ourselves either.
2386                          */
2387                         read_cache();
2388         }
2389         if (options->abbrev <= 0 || 40 < options->abbrev)
2390                 options->abbrev = 40; /* full */
2391
2392         /*
2393          * It does not make sense to show the first hit we happened
2394          * to have found.  It does not make sense not to return with
2395          * exit code in such a case either.
2396          */
2397         if (DIFF_OPT_TST(options, QUIET)) {
2398                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
2399                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2400         }
2401
2402         /*
2403          * If we postprocess in diffcore, we cannot simply return
2404          * upon the first hit.  We need to run diff as usual.
2405          */
2406         if (options->pickaxe || options->filter)
2407                 DIFF_OPT_CLR(options, QUIET);
2408
2409         return 0;
2410 }
2411
2412 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
2413 {
2414         char c, *eq;
2415         int len;
2416
2417         if (*arg != '-')
2418                 return 0;
2419         c = *++arg;
2420         if (!c)
2421                 return 0;
2422         if (c == arg_short) {
2423                 c = *++arg;
2424                 if (!c)
2425                         return 1;
2426                 if (val && isdigit(c)) {
2427                         char *end;
2428                         int n = strtoul(arg, &end, 10);
2429                         if (*end)
2430                                 return 0;
2431                         *val = n;
2432                         return 1;
2433                 }
2434                 return 0;
2435         }
2436         if (c != '-')
2437                 return 0;
2438         arg++;
2439         eq = strchr(arg, '=');
2440         if (eq)
2441                 len = eq - arg;
2442         else
2443                 len = strlen(arg);
2444         if (!len || strncmp(arg, arg_long, len))
2445                 return 0;
2446         if (eq) {
2447                 int n;
2448                 char *end;
2449                 if (!isdigit(*++eq))
2450                         return 0;
2451                 n = strtoul(eq, &end, 10);
2452                 if (*end)
2453                         return 0;
2454                 *val = n;
2455         }
2456         return 1;
2457 }
2458
2459 static int diff_scoreopt_parse(const char *opt);
2460
2461 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
2462 {
2463         const char *arg = av[0];
2464
2465         /* Output format options */
2466         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
2467                 options->output_format |= DIFF_FORMAT_PATCH;
2468         else if (opt_arg(arg, 'U', "unified", &options->context))
2469                 options->output_format |= DIFF_FORMAT_PATCH;
2470         else if (!strcmp(arg, "--raw"))
2471                 options->output_format |= DIFF_FORMAT_RAW;
2472         else if (!strcmp(arg, "--patch-with-raw"))
2473                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
2474         else if (!strcmp(arg, "--numstat"))
2475                 options->output_format |= DIFF_FORMAT_NUMSTAT;
2476         else if (!strcmp(arg, "--shortstat"))
2477                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
2478         else if (opt_arg(arg, 'X', "dirstat", &options->dirstat_percent))
2479                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2480         else if (!strcmp(arg, "--cumulative")) {
2481                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2482                 DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
2483         } else if (opt_arg(arg, 0, "dirstat-by-file",
2484                            &options->dirstat_percent)) {
2485                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2486                 DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
2487         }
2488         else if (!strcmp(arg, "--check"))
2489                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
2490         else if (!strcmp(arg, "--summary"))
2491                 options->output_format |= DIFF_FORMAT_SUMMARY;
2492         else if (!strcmp(arg, "--patch-with-stat"))
2493                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
2494         else if (!strcmp(arg, "--name-only"))
2495                 options->output_format |= DIFF_FORMAT_NAME;
2496         else if (!strcmp(arg, "--name-status"))
2497                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
2498         else if (!strcmp(arg, "-s"))
2499                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
2500         else if (!prefixcmp(arg, "--stat")) {
2501                 char *end;
2502                 int width = options->stat_width;
2503                 int name_width = options->stat_name_width;
2504                 arg += 6;
2505                 end = (char *)arg;
2506
2507                 switch (*arg) {
2508                 case '-':
2509                         if (!prefixcmp(arg, "-width="))
2510                                 width = strtoul(arg + 7, &end, 10);
2511                         else if (!prefixcmp(arg, "-name-width="))
2512                                 name_width = strtoul(arg + 12, &end, 10);
2513                         break;
2514                 case '=':
2515                         width = strtoul(arg+1, &end, 10);
2516                         if (*end == ',')
2517                                 name_width = strtoul(end+1, &end, 10);
2518                 }
2519
2520                 /* Important! This checks all the error cases! */
2521                 if (*end)
2522                         return 0;
2523                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
2524                 options->stat_name_width = name_width;
2525                 options->stat_width = width;
2526         }
2527
2528         /* renames options */
2529         else if (!prefixcmp(arg, "-B")) {
2530                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
2531                         return -1;
2532         }
2533         else if (!prefixcmp(arg, "-M")) {
2534                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2535                         return -1;
2536                 options->detect_rename = DIFF_DETECT_RENAME;
2537         }
2538         else if (!prefixcmp(arg, "-C")) {
2539                 if (options->detect_rename == DIFF_DETECT_COPY)
2540                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2541                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2542                         return -1;
2543                 options->detect_rename = DIFF_DETECT_COPY;
2544         }
2545         else if (!strcmp(arg, "--no-renames"))
2546                 options->detect_rename = 0;
2547         else if (!strcmp(arg, "--relative"))
2548                 DIFF_OPT_SET(options, RELATIVE_NAME);
2549         else if (!prefixcmp(arg, "--relative=")) {
2550                 DIFF_OPT_SET(options, RELATIVE_NAME);
2551                 options->prefix = arg + 11;
2552         }
2553
2554         /* xdiff options */
2555         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
2556                 options->xdl_opts |= XDF_IGNORE_WHITESPACE;
2557         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
2558                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2559         else if (!strcmp(arg, "--ignore-space-at-eol"))
2560                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2561
2562         /* flags options */
2563         else if (!strcmp(arg, "--binary")) {
2564                 options->output_format |= DIFF_FORMAT_PATCH;
2565                 DIFF_OPT_SET(options, BINARY);
2566         }
2567         else if (!strcmp(arg, "--full-index"))
2568                 DIFF_OPT_SET(options, FULL_INDEX);
2569         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
2570                 DIFF_OPT_SET(options, TEXT);
2571         else if (!strcmp(arg, "-R"))
2572                 DIFF_OPT_SET(options, REVERSE_DIFF);
2573         else if (!strcmp(arg, "--find-copies-harder"))
2574                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2575         else if (!strcmp(arg, "--follow"))
2576                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
2577         else if (!strcmp(arg, "--color"))
2578                 DIFF_OPT_SET(options, COLOR_DIFF);
2579         else if (!strcmp(arg, "--no-color"))
2580                 DIFF_OPT_CLR(options, COLOR_DIFF);
2581         else if (!strcmp(arg, "--color-words"))
2582                 options->flags |= DIFF_OPT_COLOR_DIFF | DIFF_OPT_COLOR_DIFF_WORDS;
2583         else if (!strcmp(arg, "--exit-code"))
2584                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2585         else if (!strcmp(arg, "--quiet"))
2586                 DIFF_OPT_SET(options, QUIET);
2587         else if (!strcmp(arg, "--ext-diff"))
2588                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
2589         else if (!strcmp(arg, "--no-ext-diff"))
2590                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
2591         else if (!strcmp(arg, "--ignore-submodules"))
2592                 DIFF_OPT_SET(options, IGNORE_SUBMODULES);
2593
2594         /* misc options */
2595         else if (!strcmp(arg, "-z"))
2596                 options->line_termination = 0;
2597         else if (!prefixcmp(arg, "-l"))
2598                 options->rename_limit = strtoul(arg+2, NULL, 10);
2599         else if (!prefixcmp(arg, "-S"))
2600                 options->pickaxe = arg + 2;
2601         else if (!strcmp(arg, "--pickaxe-all"))
2602                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
2603         else if (!strcmp(arg, "--pickaxe-regex"))
2604                 options->pickaxe_opts = DIFF_PICKAXE_REGEX;
2605         else if (!prefixcmp(arg, "-O"))
2606                 options->orderfile = arg + 2;
2607         else if (!prefixcmp(arg, "--diff-filter="))
2608                 options->filter = arg + 14;
2609         else if (!strcmp(arg, "--abbrev"))
2610                 options->abbrev = DEFAULT_ABBREV;
2611         else if (!prefixcmp(arg, "--abbrev=")) {
2612                 options->abbrev = strtoul(arg + 9, NULL, 10);
2613                 if (options->abbrev < MINIMUM_ABBREV)
2614                         options->abbrev = MINIMUM_ABBREV;
2615                 else if (40 < options->abbrev)
2616                         options->abbrev = 40;
2617         }
2618         else if (!prefixcmp(arg, "--src-prefix="))
2619                 options->a_prefix = arg + 13;
2620         else if (!prefixcmp(arg, "--dst-prefix="))
2621                 options->b_prefix = arg + 13;
2622         else if (!strcmp(arg, "--no-prefix"))
2623                 options->a_prefix = options->b_prefix = "";
2624         else if (!prefixcmp(arg, "--output=")) {
2625                 options->file = fopen(arg + strlen("--output="), "w");
2626                 options->close_file = 1;
2627         } else
2628                 return 0;
2629         return 1;
2630 }
2631
2632 static int parse_num(const char **cp_p)
2633 {
2634         unsigned long num, scale;
2635         int ch, dot;
2636         const char *cp = *cp_p;
2637
2638         num = 0;
2639         scale = 1;
2640         dot = 0;
2641         for(;;) {
2642                 ch = *cp;
2643                 if ( !dot && ch == '.' ) {
2644                         scale = 1;
2645                         dot = 1;
2646                 } else if ( ch == '%' ) {
2647                         scale = dot ? scale*100 : 100;
2648                         cp++;   /* % is always at the end */
2649                         break;
2650                 } else if ( ch >= '0' && ch <= '9' ) {
2651                         if ( scale < 100000 ) {
2652                                 scale *= 10;
2653                                 num = (num*10) + (ch-'0');
2654                         }
2655                 } else {
2656                         break;
2657                 }
2658                 cp++;
2659         }
2660         *cp_p = cp;
2661
2662         /* user says num divided by scale and we say internally that
2663          * is MAX_SCORE * num / scale.
2664          */
2665         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
2666 }
2667
2668 static int diff_scoreopt_parse(const char *opt)
2669 {
2670         int opt1, opt2, cmd;
2671
2672         if (*opt++ != '-')
2673                 return -1;
2674         cmd = *opt++;
2675         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
2676                 return -1; /* that is not a -M, -C nor -B option */
2677
2678         opt1 = parse_num(&opt);
2679         if (cmd != 'B')
2680                 opt2 = 0;
2681         else {
2682                 if (*opt == 0)
2683                         opt2 = 0;
2684                 else if (*opt != '/')
2685                         return -1; /* we expect -B80/99 or -B80 */
2686                 else {
2687                         opt++;
2688                         opt2 = parse_num(&opt);
2689                 }
2690         }
2691         if (*opt != 0)
2692                 return -1;
2693         return opt1 | (opt2 << 16);
2694 }
2695
2696 struct diff_queue_struct diff_queued_diff;
2697
2698 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
2699 {
2700         if (queue->alloc <= queue->nr) {
2701                 queue->alloc = alloc_nr(queue->alloc);
2702                 queue->queue = xrealloc(queue->queue,
2703                                         sizeof(dp) * queue->alloc);
2704         }
2705         queue->queue[queue->nr++] = dp;
2706 }
2707
2708 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
2709                                  struct diff_filespec *one,
2710                                  struct diff_filespec *two)
2711 {
2712         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
2713         dp->one = one;
2714         dp->two = two;
2715         if (queue)
2716                 diff_q(queue, dp);
2717         return dp;
2718 }
2719
2720 void diff_free_filepair(struct diff_filepair *p)
2721 {
2722         free_filespec(p->one);
2723         free_filespec(p->two);
2724         free(p);
2725 }
2726
2727 /* This is different from find_unique_abbrev() in that
2728  * it stuffs the result with dots for alignment.
2729  */
2730 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
2731 {
2732         int abblen;
2733         const char *abbrev;
2734         if (len == 40)
2735                 return sha1_to_hex(sha1);
2736
2737         abbrev = find_unique_abbrev(sha1, len);
2738         abblen = strlen(abbrev);
2739         if (abblen < 37) {
2740                 static char hex[41];
2741                 if (len < abblen && abblen <= len + 2)
2742                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
2743                 else
2744                         sprintf(hex, "%s...", abbrev);
2745                 return hex;
2746         }
2747         return sha1_to_hex(sha1);
2748 }
2749
2750 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
2751 {
2752         int line_termination = opt->line_termination;
2753         int inter_name_termination = line_termination ? '\t' : '\0';
2754
2755         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
2756                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
2757                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
2758                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
2759         }
2760         if (p->score) {
2761                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
2762                         inter_name_termination);
2763         } else {
2764                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
2765         }
2766
2767         if (p->status == DIFF_STATUS_COPIED ||
2768             p->status == DIFF_STATUS_RENAMED) {
2769                 const char *name_a, *name_b;
2770                 name_a = p->one->path;
2771                 name_b = p->two->path;
2772                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2773                 write_name_quoted(name_a, opt->file, inter_name_termination);
2774                 write_name_quoted(name_b, opt->file, line_termination);
2775         } else {
2776                 const char *name_a, *name_b;
2777                 name_a = p->one->mode ? p->one->path : p->two->path;
2778                 name_b = NULL;
2779                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2780                 write_name_quoted(name_a, opt->file, line_termination);
2781         }
2782 }
2783
2784 int diff_unmodified_pair(struct diff_filepair *p)
2785 {
2786         /* This function is written stricter than necessary to support
2787          * the currently implemented transformers, but the idea is to
2788          * let transformers to produce diff_filepairs any way they want,
2789          * and filter and clean them up here before producing the output.
2790          */
2791         struct diff_filespec *one = p->one, *two = p->two;
2792
2793         if (DIFF_PAIR_UNMERGED(p))
2794                 return 0; /* unmerged is interesting */
2795
2796         /* deletion, addition, mode or type change
2797          * and rename are all interesting.
2798          */
2799         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
2800             DIFF_PAIR_MODE_CHANGED(p) ||
2801             strcmp(one->path, two->path))
2802                 return 0;
2803
2804         /* both are valid and point at the same path.  that is, we are
2805          * dealing with a change.
2806          */
2807         if (one->sha1_valid && two->sha1_valid &&
2808             !hashcmp(one->sha1, two->sha1))
2809                 return 1; /* no change */
2810         if (!one->sha1_valid && !two->sha1_valid)
2811                 return 1; /* both look at the same file on the filesystem. */
2812         return 0;
2813 }
2814
2815 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
2816 {
2817         if (diff_unmodified_pair(p))
2818                 return;
2819
2820         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2821             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2822                 return; /* no tree diffs in patch format */
2823
2824         run_diff(p, o);
2825 }
2826
2827 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
2828                             struct diffstat_t *diffstat)
2829 {
2830         if (diff_unmodified_pair(p))
2831                 return;
2832
2833         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2834             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2835                 return; /* no tree diffs in patch format */
2836
2837         run_diffstat(p, o, diffstat);
2838 }
2839
2840 static void diff_flush_checkdiff(struct diff_filepair *p,
2841                 struct diff_options *o)
2842 {
2843         if (diff_unmodified_pair(p))
2844                 return;
2845
2846         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2847             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2848                 return; /* no tree diffs in patch format */
2849
2850         run_checkdiff(p, o);
2851 }
2852
2853 int diff_queue_is_empty(void)
2854 {
2855         struct diff_queue_struct *q = &diff_queued_diff;
2856         int i;
2857         for (i = 0; i < q->nr; i++)
2858                 if (!diff_unmodified_pair(q->queue[i]))
2859                         return 0;
2860         return 1;
2861 }
2862
2863 #if DIFF_DEBUG
2864 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
2865 {
2866         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
2867                 x, one ? one : "",
2868                 s->path,
2869                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
2870                 s->mode,
2871                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
2872         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
2873                 x, one ? one : "",
2874                 s->size, s->xfrm_flags);
2875 }
2876
2877 void diff_debug_filepair(const struct diff_filepair *p, int i)
2878 {
2879         diff_debug_filespec(p->one, i, "one");
2880         diff_debug_filespec(p->two, i, "two");
2881         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
2882                 p->score, p->status ? p->status : '?',
2883                 p->one->rename_used, p->broken_pair);
2884 }
2885
2886 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
2887 {
2888         int i;
2889         if (msg)
2890                 fprintf(stderr, "%s\n", msg);
2891         fprintf(stderr, "q->nr = %d\n", q->nr);
2892         for (i = 0; i < q->nr; i++) {
2893                 struct diff_filepair *p = q->queue[i];
2894                 diff_debug_filepair(p, i);
2895         }
2896 }
2897 #endif
2898
2899 static void diff_resolve_rename_copy(void)
2900 {
2901         int i;
2902         struct diff_filepair *p;
2903         struct diff_queue_struct *q = &diff_queued_diff;
2904
2905         diff_debug_queue("resolve-rename-copy", q);
2906
2907         for (i = 0; i < q->nr; i++) {
2908                 p = q->queue[i];
2909                 p->status = 0; /* undecided */
2910                 if (DIFF_PAIR_UNMERGED(p))
2911                         p->status = DIFF_STATUS_UNMERGED;
2912                 else if (!DIFF_FILE_VALID(p->one))
2913                         p->status = DIFF_STATUS_ADDED;
2914                 else if (!DIFF_FILE_VALID(p->two))
2915                         p->status = DIFF_STATUS_DELETED;
2916                 else if (DIFF_PAIR_TYPE_CHANGED(p))
2917                         p->status = DIFF_STATUS_TYPE_CHANGED;
2918
2919                 /* from this point on, we are dealing with a pair
2920                  * whose both sides are valid and of the same type, i.e.
2921                  * either in-place edit or rename/copy edit.
2922                  */
2923                 else if (DIFF_PAIR_RENAME(p)) {
2924                         /*
2925                          * A rename might have re-connected a broken
2926                          * pair up, causing the pathnames to be the
2927                          * same again. If so, that's not a rename at
2928                          * all, just a modification..
2929                          *
2930                          * Otherwise, see if this source was used for
2931                          * multiple renames, in which case we decrement
2932                          * the count, and call it a copy.
2933                          */
2934                         if (!strcmp(p->one->path, p->two->path))
2935                                 p->status = DIFF_STATUS_MODIFIED;
2936                         else if (--p->one->rename_used > 0)
2937                                 p->status = DIFF_STATUS_COPIED;
2938                         else
2939                                 p->status = DIFF_STATUS_RENAMED;
2940                 }
2941                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
2942                          p->one->mode != p->two->mode ||
2943                          is_null_sha1(p->one->sha1))
2944                         p->status = DIFF_STATUS_MODIFIED;
2945                 else {
2946                         /* This is a "no-change" entry and should not
2947                          * happen anymore, but prepare for broken callers.
2948                          */
2949                         error("feeding unmodified %s to diffcore",
2950                               p->one->path);
2951                         p->status = DIFF_STATUS_UNKNOWN;
2952                 }
2953         }
2954         diff_debug_queue("resolve-rename-copy done", q);
2955 }
2956
2957 static int check_pair_status(struct diff_filepair *p)
2958 {
2959         switch (p->status) {
2960         case DIFF_STATUS_UNKNOWN:
2961                 return 0;
2962         case 0:
2963                 die("internal error in diff-resolve-rename-copy");
2964         default:
2965                 return 1;
2966         }
2967 }
2968
2969 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
2970 {
2971         int fmt = opt->output_format;
2972
2973         if (fmt & DIFF_FORMAT_CHECKDIFF)
2974                 diff_flush_checkdiff(p, opt);
2975         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
2976                 diff_flush_raw(p, opt);
2977         else if (fmt & DIFF_FORMAT_NAME) {
2978                 const char *name_a, *name_b;
2979                 name_a = p->two->path;
2980                 name_b = NULL;
2981                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2982                 write_name_quoted(name_a, opt->file, opt->line_termination);
2983         }
2984 }
2985
2986 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
2987 {
2988         if (fs->mode)
2989                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
2990         else
2991                 fprintf(file, " %s ", newdelete);
2992         write_name_quoted(fs->path, file, '\n');
2993 }
2994
2995
2996 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name)
2997 {
2998         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
2999                 fprintf(file, " mode change %06o => %06o%c", p->one->mode, p->two->mode,
3000                         show_name ? ' ' : '\n');
3001                 if (show_name) {
3002                         write_name_quoted(p->two->path, file, '\n');
3003                 }
3004         }
3005 }
3006
3007 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p)
3008 {
3009         char *names = pprint_rename(p->one->path, p->two->path);
3010
3011         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
3012         free(names);
3013         show_mode_change(file, p, 0);
3014 }
3015
3016 static void diff_summary(FILE *file, struct diff_filepair *p)
3017 {
3018         switch(p->status) {
3019         case DIFF_STATUS_DELETED:
3020                 show_file_mode_name(file, "delete", p->one);
3021                 break;
3022         case DIFF_STATUS_ADDED:
3023                 show_file_mode_name(file, "create", p->two);
3024                 break;
3025         case DIFF_STATUS_COPIED:
3026                 show_rename_copy(file, "copy", p);
3027                 break;
3028         case DIFF_STATUS_RENAMED:
3029                 show_rename_copy(file, "rename", p);
3030                 break;
3031         default:
3032                 if (p->score) {
3033                         fputs(" rewrite ", file);
3034                         write_name_quoted(p->two->path, file, ' ');
3035                         fprintf(file, "(%d%%)\n", similarity_index(p));
3036                 }
3037                 show_mode_change(file, p, !p->score);
3038                 break;
3039         }
3040 }
3041
3042 struct patch_id_t {
3043         SHA_CTX *ctx;
3044         int patchlen;
3045 };
3046
3047 static int remove_space(char *line, int len)
3048 {
3049         int i;
3050         char *dst = line;
3051         unsigned char c;
3052
3053         for (i = 0; i < len; i++)
3054                 if (!isspace((c = line[i])))
3055                         *dst++ = c;
3056
3057         return dst - line;
3058 }
3059
3060 static void patch_id_consume(void *priv, char *line, unsigned long len)
3061 {
3062         struct patch_id_t *data = priv;
3063         int new_len;
3064
3065         /* Ignore line numbers when computing the SHA1 of the patch */
3066         if (!prefixcmp(line, "@@ -"))
3067                 return;
3068
3069         new_len = remove_space(line, len);
3070
3071         SHA1_Update(data->ctx, line, new_len);
3072         data->patchlen += new_len;
3073 }
3074
3075 /* returns 0 upon success, and writes result into sha1 */
3076 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
3077 {
3078         struct diff_queue_struct *q = &diff_queued_diff;
3079         int i;
3080         SHA_CTX ctx;
3081         struct patch_id_t data;
3082         char buffer[PATH_MAX * 4 + 20];
3083
3084         SHA1_Init(&ctx);
3085         memset(&data, 0, sizeof(struct patch_id_t));
3086         data.ctx = &ctx;
3087
3088         for (i = 0; i < q->nr; i++) {
3089                 xpparam_t xpp;
3090                 xdemitconf_t xecfg;
3091                 xdemitcb_t ecb;
3092                 mmfile_t mf1, mf2;
3093                 struct diff_filepair *p = q->queue[i];
3094                 int len1, len2;
3095
3096                 memset(&xecfg, 0, sizeof(xecfg));
3097                 if (p->status == 0)
3098                         return error("internal diff status error");
3099                 if (p->status == DIFF_STATUS_UNKNOWN)
3100                         continue;
3101                 if (diff_unmodified_pair(p))
3102                         continue;
3103                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3104                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3105                         continue;
3106                 if (DIFF_PAIR_UNMERGED(p))
3107                         continue;
3108
3109                 diff_fill_sha1_info(p->one);
3110                 diff_fill_sha1_info(p->two);
3111                 if (fill_mmfile(&mf1, p->one) < 0 ||
3112                                 fill_mmfile(&mf2, p->two) < 0)
3113                         return error("unable to read files to diff");
3114
3115                 len1 = remove_space(p->one->path, strlen(p->one->path));
3116                 len2 = remove_space(p->two->path, strlen(p->two->path));
3117                 if (p->one->mode == 0)
3118                         len1 = snprintf(buffer, sizeof(buffer),
3119                                         "diff--gita/%.*sb/%.*s"
3120                                         "newfilemode%06o"
3121                                         "---/dev/null"
3122                                         "+++b/%.*s",
3123                                         len1, p->one->path,
3124                                         len2, p->two->path,
3125                                         p->two->mode,
3126                                         len2, p->two->path);
3127                 else if (p->two->mode == 0)
3128                         len1 = snprintf(buffer, sizeof(buffer),
3129                                         "diff--gita/%.*sb/%.*s"
3130                                         "deletedfilemode%06o"
3131                                         "---a/%.*s"
3132                                         "+++/dev/null",
3133                                         len1, p->one->path,
3134                                         len2, p->two->path,
3135                                         p->one->mode,
3136                                         len1, p->one->path);
3137                 else
3138                         len1 = snprintf(buffer, sizeof(buffer),
3139                                         "diff--gita/%.*sb/%.*s"
3140                                         "---a/%.*s"
3141                                         "+++b/%.*s",
3142                                         len1, p->one->path,
3143                                         len2, p->two->path,
3144                                         len1, p->one->path,
3145                                         len2, p->two->path);
3146                 SHA1_Update(&ctx, buffer, len1);
3147
3148                 xpp.flags = XDF_NEED_MINIMAL;
3149                 xecfg.ctxlen = 3;
3150                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3151                 xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
3152                               &xpp, &xecfg, &ecb);
3153         }
3154
3155         SHA1_Final(sha1, &ctx);
3156         return 0;
3157 }
3158
3159 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
3160 {
3161         struct diff_queue_struct *q = &diff_queued_diff;
3162         int i;
3163         int result = diff_get_patch_id(options, sha1);
3164
3165         for (i = 0; i < q->nr; i++)
3166                 diff_free_filepair(q->queue[i]);
3167
3168         free(q->queue);
3169         q->queue = NULL;
3170         q->nr = q->alloc = 0;
3171
3172         return result;
3173 }
3174
3175 static int is_summary_empty(const struct diff_queue_struct *q)
3176 {
3177         int i;
3178
3179         for (i = 0; i < q->nr; i++) {
3180                 const struct diff_filepair *p = q->queue[i];
3181
3182                 switch (p->status) {
3183                 case DIFF_STATUS_DELETED:
3184                 case DIFF_STATUS_ADDED:
3185                 case DIFF_STATUS_COPIED:
3186                 case DIFF_STATUS_RENAMED:
3187                         return 0;
3188                 default:
3189                         if (p->score)
3190                                 return 0;
3191                         if (p->one->mode && p->two->mode &&
3192                             p->one->mode != p->two->mode)
3193                                 return 0;
3194                         break;
3195                 }
3196         }
3197         return 1;
3198 }
3199
3200 void diff_flush(struct diff_options *options)
3201 {
3202         struct diff_queue_struct *q = &diff_queued_diff;
3203         int i, output_format = options->output_format;
3204         int separator = 0;
3205
3206         /*
3207          * Order: raw, stat, summary, patch
3208          * or:    name/name-status/checkdiff (other bits clear)
3209          */
3210         if (!q->nr)
3211                 goto free_queue;
3212
3213         if (output_format & (DIFF_FORMAT_RAW |
3214                              DIFF_FORMAT_NAME |
3215                              DIFF_FORMAT_NAME_STATUS |
3216                              DIFF_FORMAT_CHECKDIFF)) {
3217                 for (i = 0; i < q->nr; i++) {
3218                         struct diff_filepair *p = q->queue[i];
3219                         if (check_pair_status(p))
3220                                 flush_one_pair(p, options);
3221                 }
3222                 separator++;
3223         }
3224
3225         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT)) {
3226                 struct diffstat_t diffstat;
3227
3228                 memset(&diffstat, 0, sizeof(struct diffstat_t));
3229                 for (i = 0; i < q->nr; i++) {
3230                         struct diff_filepair *p = q->queue[i];
3231                         if (check_pair_status(p))
3232                                 diff_flush_stat(p, options, &diffstat);
3233                 }
3234                 if (output_format & DIFF_FORMAT_NUMSTAT)
3235                         show_numstat(&diffstat, options);
3236                 if (output_format & DIFF_FORMAT_DIFFSTAT)
3237                         show_stats(&diffstat, options);
3238                 if (output_format & DIFF_FORMAT_SHORTSTAT)
3239                         show_shortstats(&diffstat, options);
3240                 free_diffstat_info(&diffstat);
3241                 separator++;
3242         }
3243         if (output_format & DIFF_FORMAT_DIRSTAT)
3244                 show_dirstat(options);
3245
3246         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
3247                 for (i = 0; i < q->nr; i++)
3248                         diff_summary(options->file, q->queue[i]);
3249                 separator++;
3250         }
3251
3252         if (output_format & DIFF_FORMAT_PATCH) {
3253                 if (separator) {
3254                         putc(options->line_termination, options->file);
3255                         if (options->stat_sep) {
3256                                 /* attach patch instead of inline */
3257                                 fputs(options->stat_sep, options->file);
3258                         }
3259                 }
3260
3261                 for (i = 0; i < q->nr; i++) {
3262                         struct diff_filepair *p = q->queue[i];
3263                         if (check_pair_status(p))
3264                                 diff_flush_patch(p, options);
3265                 }
3266         }
3267
3268         if (output_format & DIFF_FORMAT_CALLBACK)
3269                 options->format_callback(q, options, options->format_callback_data);
3270
3271         for (i = 0; i < q->nr; i++)
3272                 diff_free_filepair(q->queue[i]);
3273 free_queue:
3274         free(q->queue);
3275         q->queue = NULL;
3276         q->nr = q->alloc = 0;
3277         if (options->close_file)
3278                 fclose(options->file);
3279 }
3280
3281 static void diffcore_apply_filter(const char *filter)
3282 {
3283         int i;
3284         struct diff_queue_struct *q = &diff_queued_diff;
3285         struct diff_queue_struct outq;
3286         outq.queue = NULL;
3287         outq.nr = outq.alloc = 0;
3288
3289         if (!filter)
3290                 return;
3291
3292         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
3293                 int found;
3294                 for (i = found = 0; !found && i < q->nr; i++) {
3295                         struct diff_filepair *p = q->queue[i];
3296                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3297                              ((p->score &&
3298                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3299                               (!p->score &&
3300                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3301                             ((p->status != DIFF_STATUS_MODIFIED) &&
3302                              strchr(filter, p->status)))
3303                                 found++;
3304                 }
3305                 if (found)
3306                         return;
3307
3308                 /* otherwise we will clear the whole queue
3309                  * by copying the empty outq at the end of this
3310                  * function, but first clear the current entries
3311                  * in the queue.
3312                  */
3313                 for (i = 0; i < q->nr; i++)
3314                         diff_free_filepair(q->queue[i]);
3315         }
3316         else {
3317                 /* Only the matching ones */
3318                 for (i = 0; i < q->nr; i++) {
3319                         struct diff_filepair *p = q->queue[i];
3320
3321                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3322                              ((p->score &&
3323                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3324                               (!p->score &&
3325                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3326                             ((p->status != DIFF_STATUS_MODIFIED) &&
3327                              strchr(filter, p->status)))
3328                                 diff_q(&outq, p);
3329                         else
3330                                 diff_free_filepair(p);
3331                 }
3332         }
3333         free(q->queue);
3334         *q = outq;
3335 }
3336
3337 /* Check whether two filespecs with the same mode and size are identical */
3338 static int diff_filespec_is_identical(struct diff_filespec *one,
3339                                       struct diff_filespec *two)
3340 {
3341         if (S_ISGITLINK(one->mode))
3342                 return 0;
3343         if (diff_populate_filespec(one, 0))
3344                 return 0;
3345         if (diff_populate_filespec(two, 0))
3346                 return 0;
3347         return !memcmp(one->data, two->data, one->size);
3348 }
3349
3350 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
3351 {
3352         int i;
3353         struct diff_queue_struct *q = &diff_queued_diff;
3354         struct diff_queue_struct outq;
3355         outq.queue = NULL;
3356         outq.nr = outq.alloc = 0;
3357
3358         for (i = 0; i < q->nr; i++) {
3359                 struct diff_filepair *p = q->queue[i];
3360
3361                 /*
3362                  * 1. Entries that come from stat info dirtyness
3363                  *    always have both sides (iow, not create/delete),
3364                  *    one side of the object name is unknown, with
3365                  *    the same mode and size.  Keep the ones that
3366                  *    do not match these criteria.  They have real
3367                  *    differences.
3368                  *
3369                  * 2. At this point, the file is known to be modified,
3370                  *    with the same mode and size, and the object
3371                  *    name of one side is unknown.  Need to inspect
3372                  *    the identical contents.
3373                  */
3374                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
3375                     !DIFF_FILE_VALID(p->two) ||
3376                     (p->one->sha1_valid && p->two->sha1_valid) ||
3377                     (p->one->mode != p->two->mode) ||
3378                     diff_populate_filespec(p->one, 1) ||
3379                     diff_populate_filespec(p->two, 1) ||
3380                     (p->one->size != p->two->size) ||
3381                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
3382                         diff_q(&outq, p);
3383                 else {
3384                         /*
3385                          * The caller can subtract 1 from skip_stat_unmatch
3386                          * to determine how many paths were dirty only
3387                          * due to stat info mismatch.
3388                          */
3389                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
3390                                 diffopt->skip_stat_unmatch++;
3391                         diff_free_filepair(p);
3392                 }
3393         }
3394         free(q->queue);
3395         *q = outq;
3396 }
3397
3398 void diffcore_std(struct diff_options *options)
3399 {
3400         if (DIFF_OPT_TST(options, QUIET))
3401                 return;
3402
3403         if (options->skip_stat_unmatch && !DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3404                 diffcore_skip_stat_unmatch(options);
3405         if (options->break_opt != -1)
3406                 diffcore_break(options->break_opt);
3407         if (options->detect_rename)
3408                 diffcore_rename(options);
3409         if (options->break_opt != -1)
3410                 diffcore_merge_broken();
3411         if (options->pickaxe)
3412                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
3413         if (options->orderfile)
3414                 diffcore_order(options->orderfile);
3415         diff_resolve_rename_copy();
3416         diffcore_apply_filter(options->filter);
3417
3418         if (diff_queued_diff.nr)
3419                 DIFF_OPT_SET(options, HAS_CHANGES);
3420         else
3421                 DIFF_OPT_CLR(options, HAS_CHANGES);
3422 }
3423
3424 int diff_result_code(struct diff_options *opt, int status)
3425 {
3426         int result = 0;
3427         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3428             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
3429                 return status;
3430         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3431             DIFF_OPT_TST(opt, HAS_CHANGES))
3432                 result |= 01;
3433         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
3434             DIFF_OPT_TST(opt, CHECK_FAILED))
3435                 result |= 02;
3436         return result;
3437 }
3438
3439 void diff_addremove(struct diff_options *options,
3440                     int addremove, unsigned mode,
3441                     const unsigned char *sha1,
3442                     const char *concatpath)
3443 {
3444         struct diff_filespec *one, *two;
3445
3446         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(mode))
3447                 return;
3448
3449         /* This may look odd, but it is a preparation for
3450          * feeding "there are unchanged files which should
3451          * not produce diffs, but when you are doing copy
3452          * detection you would need them, so here they are"
3453          * entries to the diff-core.  They will be prefixed
3454          * with something like '=' or '*' (I haven't decided
3455          * which but should not make any difference).
3456          * Feeding the same new and old to diff_change()
3457          * also has the same effect.
3458          * Before the final output happens, they are pruned after
3459          * merged into rename/copy pairs as appropriate.
3460          */
3461         if (DIFF_OPT_TST(options, REVERSE_DIFF))
3462                 addremove = (addremove == '+' ? '-' :
3463                              addremove == '-' ? '+' : addremove);
3464
3465         if (options->prefix &&
3466             strncmp(concatpath, options->prefix, options->prefix_length))
3467                 return;
3468
3469         one = alloc_filespec(concatpath);
3470         two = alloc_filespec(concatpath);
3471
3472         if (addremove != '+')
3473                 fill_filespec(one, sha1, mode);
3474         if (addremove != '-')
3475                 fill_filespec(two, sha1, mode);
3476
3477         diff_queue(&diff_queued_diff, one, two);
3478         DIFF_OPT_SET(options, HAS_CHANGES);
3479 }
3480
3481 void diff_change(struct diff_options *options,
3482                  unsigned old_mode, unsigned new_mode,
3483                  const unsigned char *old_sha1,
3484                  const unsigned char *new_sha1,
3485                  const char *concatpath)
3486 {
3487         struct diff_filespec *one, *two;
3488
3489         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(old_mode)
3490                         && S_ISGITLINK(new_mode))
3491                 return;
3492
3493         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
3494                 unsigned tmp;
3495                 const unsigned char *tmp_c;
3496                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
3497                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
3498         }
3499
3500         if (options->prefix &&
3501             strncmp(concatpath, options->prefix, options->prefix_length))
3502                 return;
3503
3504         one = alloc_filespec(concatpath);
3505         two = alloc_filespec(concatpath);
3506         fill_filespec(one, old_sha1, old_mode);
3507         fill_filespec(two, new_sha1, new_mode);
3508
3509         diff_queue(&diff_queued_diff, one, two);
3510         DIFF_OPT_SET(options, HAS_CHANGES);
3511 }
3512
3513 void diff_unmerge(struct diff_options *options,
3514                   const char *path,
3515                   unsigned mode, const unsigned char *sha1)
3516 {
3517         struct diff_filespec *one, *two;
3518
3519         if (options->prefix &&
3520             strncmp(path, options->prefix, options->prefix_length))
3521                 return;
3522
3523         one = alloc_filespec(path);
3524         two = alloc_filespec(path);
3525         fill_filespec(one, sha1, mode);
3526         diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
3527 }