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