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