diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include <sys/types.h>
   5 #include <sys/wait.h>
   6 #include <signal.h>
   7 #include "cache.h"
   8 #include "quote.h"
   9 #include "diff.h"
  10 #include "diffcore.h"
  11
  12 static const char *diff_opts = "-pu";
  13
  14 static int use_size_cache;
  15
  16 int diff_rename_limit_default = -1;
  17
  18 int git_diff_config(const char *var, const char *value)
  19 {
  20         if (!strcmp(var, "diff.renamelimit")) {
  21                 diff_rename_limit_default = git_config_int(var, value);
  22                 return 0;
  23         }
  24
  25         return git_default_config(var, value);
  26 }
  27
  28 static char *quote_one(const char *str)
  29 {
  30         int needlen;
  31         char *xp;
  32
  33         if (!str)
  34                 return NULL;
  35         needlen = quote_c_style(str, NULL, NULL, 0);
  36         if (!needlen)
  37                 return strdup(str);
  38         xp = xmalloc(needlen + 1);
  39         quote_c_style(str, xp, NULL, 0);
  40         return xp;
  41 }
  42
  43 static char *quote_two(const char *one, const char *two)
  44 {
  45         int need_one = quote_c_style(one, NULL, NULL, 1);
  46         int need_two = quote_c_style(two, NULL, NULL, 1);
  47         char *xp;
  48
  49         if (need_one + need_two) {
  50                 if (!need_one) need_one = strlen(one);
  51                 if (!need_two) need_one = strlen(two);
  52
  53                 xp = xmalloc(need_one + need_two + 3);
  54                 xp[0] = '"';
  55                 quote_c_style(one, xp + 1, NULL, 1);
  56                 quote_c_style(two, xp + need_one + 1, NULL, 1);
  57                 strcpy(xp + need_one + need_two + 1, "\"");
  58                 return xp;
  59         }
  60         need_one = strlen(one);
  61         need_two = strlen(two);
  62         xp = xmalloc(need_one + need_two + 1);
  63         strcpy(xp, one);
  64         strcpy(xp + need_one, two);
  65         return xp;
  66 }
  67
  68 static const char *external_diff(void)
  69 {
  70         static const char *external_diff_cmd = NULL;
  71         static int done_preparing = 0;
  72         const char *env_diff_opts;
  73
  74         if (done_preparing)
  75                 return external_diff_cmd;
  76
  77         /*
  78          * Default values above are meant to match the
  79          * Linux kernel development style.  Examples of
  80          * alternative styles you can specify via environment
  81          * variables are:
  82          *
  83          * GIT_DIFF_OPTS="-c";
  84          */
  85         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
  86
  87         /* In case external diff fails... */
  88         env_diff_opts = getenv("GIT_DIFF_OPTS");
  89         if (env_diff_opts) diff_opts = env_diff_opts;
  90
  91         done_preparing = 1;
  92         return external_diff_cmd;
  93 }
  94
  95 #define TEMPFILE_PATH_LEN               50
  96
  97 static struct diff_tempfile {
  98         const char *name; /* filename external diff should read from */
  99         char hex[41];
 100         char mode[10];
 101         char tmp_path[TEMPFILE_PATH_LEN];
 102 } diff_temp[2];
 103
 104 static int count_lines(const char *filename)
 105 {
 106         FILE *in;
 107         int count, ch, completely_empty = 1, nl_just_seen = 0;
 108         in = fopen(filename, "r");
 109         count = 0;
 110         while ((ch = fgetc(in)) != EOF)
 111                 if (ch == '\n') {
 112                         count++;
 113                         nl_just_seen = 1;
 114                         completely_empty = 0;
 115                 }
 116                 else {
 117                         nl_just_seen = 0;
 118                         completely_empty = 0;
 119                 }
 120         fclose(in);
 121         if (completely_empty)
 122                 return 0;
 123         if (!nl_just_seen)
 124                 count++; /* no trailing newline */
 125         return count;
 126 }
 127
 128 static void print_line_count(int count)
 129 {
 130         switch (count) {
 131         case 0:
 132                 printf("0,0");
 133                 break;
 134         case 1:
 135                 printf("1");
 136                 break;
 137         default:
 138                 printf("1,%d", count);
 139                 break;
 140         }
 141 }
 142
 143 static void copy_file(int prefix, const char *filename)
 144 {
 145         FILE *in;
 146         int ch, nl_just_seen = 1;
 147         in = fopen(filename, "r");
 148         while ((ch = fgetc(in)) != EOF) {
 149                 if (nl_just_seen)
 150                         putchar(prefix);
 151                 putchar(ch);
 152                 if (ch == '\n')
 153                         nl_just_seen = 1;
 154                 else
 155                         nl_just_seen = 0;
 156         }
 157         fclose(in);
 158         if (!nl_just_seen)
 159                 printf("\n\\ No newline at end of file\n");
 160 }
 161
 162 static void emit_rewrite_diff(const char *name_a,
 163                               const char *name_b,
 164                               struct diff_tempfile *temp)
 165 {
 166         /* Use temp[i].name as input, name_a and name_b as labels */
 167         int lc_a, lc_b;
 168         lc_a = count_lines(temp[0].name);
 169         lc_b = count_lines(temp[1].name);
 170         printf("--- %s\n+++ %s\n@@ -", name_a, name_b);
 171         print_line_count(lc_a);
 172         printf(" +");
 173         print_line_count(lc_b);
 174         printf(" @@\n");
 175         if (lc_a)
 176                 copy_file('-', temp[0].name);
 177         if (lc_b)
 178                 copy_file('+', temp[1].name);
 179 }
 180
 181 static const char *builtin_diff(const char *name_a,
 182                          const char *name_b,
 183                          struct diff_tempfile *temp,
 184                          const char *xfrm_msg,
 185                          int complete_rewrite,
 186                          const char **args)
 187 {
 188         int i, next_at, cmd_size;
 189         const char *const diff_cmd = "diff -L%s -L%s";
 190         const char *const diff_arg  = "-- %s %s||:"; /* "||:" is to return 0 */
 191         const char *input_name_sq[2];
 192         const char *label_path[2];
 193         char *cmd;
 194
 195         /* diff_cmd and diff_arg have 4 %s in total which makes
 196          * the sum of these strings 8 bytes larger than required.
 197          * we use 2 spaces around diff-opts, and we need to count
 198          * terminating NUL; we used to subtract 5 here, but we do not
 199          * care about small leaks in this subprocess that is about
 200          * to exec "diff" anymore.
 201          */
 202         cmd_size = (strlen(diff_cmd) + strlen(diff_opts) + strlen(diff_arg)
 203                     + 128);
 204
 205         for (i = 0; i < 2; i++) {
 206                 input_name_sq[i] = sq_quote(temp[i].name);
 207                 if (!strcmp(temp[i].name, "/dev/null"))
 208                         label_path[i] = "/dev/null";
 209                 else if (!i)
 210                         label_path[i] = sq_quote(quote_two("a/", name_a));
 211                 else
 212                         label_path[i] = sq_quote(quote_two("b/", name_b));
 213                 cmd_size += (strlen(label_path[i]) + strlen(input_name_sq[i]));
 214         }
 215
 216         cmd = xmalloc(cmd_size);
 217
 218         next_at = 0;
 219         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 220                             diff_cmd, label_path[0], label_path[1]);
 221         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 222                             " %s ", diff_opts);
 223         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 224                             diff_arg, input_name_sq[0], input_name_sq[1]);
 225
 226         printf("diff --git %s %s\n",
 227                quote_two("a/", name_a), quote_two("b/", name_b));
 228         if (label_path[0][0] == '/') {
 229                 /* dev/null */
 230                 printf("new file mode %s\n", temp[1].mode);
 231                 if (xfrm_msg && xfrm_msg[0])
 232                         puts(xfrm_msg);
 233         }
 234         else if (label_path[1][0] == '/') {
 235                 printf("deleted file mode %s\n", temp[0].mode);
 236                 if (xfrm_msg && xfrm_msg[0])
 237                         puts(xfrm_msg);
 238         }
 239         else {
 240                 if (strcmp(temp[0].mode, temp[1].mode)) {
 241                         printf("old mode %s\n", temp[0].mode);
 242                         printf("new mode %s\n", temp[1].mode);
 243                 }
 244                 if (xfrm_msg && xfrm_msg[0])
 245                         puts(xfrm_msg);
 246                 /*
 247                  * we do not run diff between different kind
 248                  * of objects.
 249                  */
 250                 if (strncmp(temp[0].mode, temp[1].mode, 3))
 251                         return NULL;
 252                 if (complete_rewrite) {
 253                         emit_rewrite_diff(name_a, name_b, temp);
 254                         return NULL;
 255                 }
 256         }
 257
 258         /* This is disgusting */
 259         *args++ = "sh";
 260         *args++ = "-c";
 261         *args++ = cmd;
 262         *args = NULL;
 263         return "/bin/sh";
 264 }
 265
 266 struct diff_filespec *alloc_filespec(const char *path)
 267 {
 268         int namelen = strlen(path);
 269         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
 270
 271         memset(spec, 0, sizeof(*spec));
 272         spec->path = (char *)(spec + 1);
 273         memcpy(spec->path, path, namelen+1);
 274         return spec;
 275 }
 276
 277 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 278                    unsigned short mode)
 279 {
 280         if (mode) {
 281                 spec->mode = DIFF_FILE_CANON_MODE(mode);
 282                 memcpy(spec->sha1, sha1, 20);
 283                 spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
 284         }
 285 }
 286
 287 /*
 288  * Given a name and sha1 pair, if the dircache tells us the file in
 289  * the work tree has that object contents, return true, so that
 290  * prepare_temp_file() does not have to inflate and extract.
 291  */
 292 static int work_tree_matches(const char *name, const unsigned char *sha1)
 293 {
 294         struct cache_entry *ce;
 295         struct stat st;
 296         int pos, len;
 297
 298         /* We do not read the cache ourselves here, because the
 299          * benchmark with my previous version that always reads cache
 300          * shows that it makes things worse for diff-tree comparing
 301          * two linux-2.6 kernel trees in an already checked out work
 302          * tree.  This is because most diff-tree comparisons deal with
 303          * only a small number of files, while reading the cache is
 304          * expensive for a large project, and its cost outweighs the
 305          * savings we get by not inflating the object to a temporary
 306          * file.  Practically, this code only helps when we are used
 307          * by diff-cache --cached, which does read the cache before
 308          * calling us.
 309          */
 310         if (!active_cache)
 311                 return 0;
 312
 313         len = strlen(name);
 314         pos = cache_name_pos(name, len);
 315         if (pos < 0)
 316                 return 0;
 317         ce = active_cache[pos];
 318         if ((lstat(name, &st) < 0) ||
 319             !S_ISREG(st.st_mode) || /* careful! */
 320             ce_match_stat(ce, &st, 0) ||
 321             memcmp(sha1, ce->sha1, 20))
 322                 return 0;
 323         /* we return 1 only when we can stat, it is a regular file,
 324          * stat information matches, and sha1 recorded in the cache
 325          * matches.  I.e. we know the file in the work tree really is
 326          * the same as the <name, sha1> pair.
 327          */
 328         return 1;
 329 }
 330
 331 static struct sha1_size_cache {
 332         unsigned char sha1[20];
 333         unsigned long size;
 334 } **sha1_size_cache;
 335 static int sha1_size_cache_nr, sha1_size_cache_alloc;
 336
 337 static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
 338                                                  int find_only,
 339                                                  unsigned long size)
 340 {
 341         int first, last;
 342         struct sha1_size_cache *e;
 343
 344         first = 0;
 345         last = sha1_size_cache_nr;
 346         while (last > first) {
 347                 int cmp, next = (last + first) >> 1;
 348                 e = sha1_size_cache[next];
 349                 cmp = memcmp(e->sha1, sha1, 20);
 350                 if (!cmp)
 351                         return e;
 352                 if (cmp < 0) {
 353                         last = next;
 354                         continue;
 355                 }
 356                 first = next+1;
 357         }
 358         /* not found */
 359         if (find_only)
 360                 return NULL;
 361         /* insert to make it at "first" */
 362         if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
 363                 sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
 364                 sha1_size_cache = xrealloc(sha1_size_cache,
 365                                            sha1_size_cache_alloc *
 366                                            sizeof(*sha1_size_cache));
 367         }
 368         sha1_size_cache_nr++;
 369         if (first < sha1_size_cache_nr)
 370                 memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
 371                         (sha1_size_cache_nr - first - 1) *
 372                         sizeof(*sha1_size_cache));
 373         e = xmalloc(sizeof(struct sha1_size_cache));
 374         sha1_size_cache[first] = e;
 375         memcpy(e->sha1, sha1, 20);
 376         e->size = size;
 377         return e;
 378 }
 379
 380 /*
 381  * While doing rename detection and pickaxe operation, we may need to
 382  * grab the data for the blob (or file) for our own in-core comparison.
 383  * diff_filespec has data and size fields for this purpose.
 384  */
 385 int diff_populate_filespec(struct diff_filespec *s, int size_only)
 386 {
 387         int err = 0;
 388         if (!DIFF_FILE_VALID(s))
 389                 die("internal error: asking to populate invalid file.");
 390         if (S_ISDIR(s->mode))
 391                 return -1;
 392
 393         if (!use_size_cache)
 394                 size_only = 0;
 395
 396         if (s->data)
 397                 return err;
 398         if (!s->sha1_valid ||
 399             work_tree_matches(s->path, s->sha1)) {
 400                 struct stat st;
 401                 int fd;
 402                 if (lstat(s->path, &st) < 0) {
 403                         if (errno == ENOENT) {
 404                         err_empty:
 405                                 err = -1;
 406                         empty:
 407                                 s->data = "";
 408                                 s->size = 0;
 409                                 return err;
 410                         }
 411                 }
 412                 s->size = st.st_size;
 413                 if (!s->size)
 414                         goto empty;
 415                 if (size_only)
 416                         return 0;
 417                 if (S_ISLNK(st.st_mode)) {
 418                         int ret;
 419                         s->data = xmalloc(s->size);
 420                         s->should_free = 1;
 421                         ret = readlink(s->path, s->data, s->size);
 422                         if (ret < 0) {
 423                                 free(s->data);
 424                                 goto err_empty;
 425                         }
 426                         return 0;
 427                 }
 428                 fd = open(s->path, O_RDONLY);
 429                 if (fd < 0)
 430                         goto err_empty;
 431                 s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
 432                 close(fd);
 433                 if (s->data == MAP_FAILED)
 434                         goto err_empty;
 435                 s->should_munmap = 1;
 436         }
 437         else {
 438                 char type[20];
 439                 struct sha1_size_cache *e;
 440
 441                 if (size_only) {
 442                         e = locate_size_cache(s->sha1, 1, 0);
 443                         if (e) {
 444                                 s->size = e->size;
 445                                 return 0;
 446                         }
 447                         if (!sha1_object_info(s->sha1, type, &s->size))
 448                                 locate_size_cache(s->sha1, 0, s->size);
 449                 }
 450                 else {
 451                         s->data = read_sha1_file(s->sha1, type, &s->size);
 452                         s->should_free = 1;
 453                 }
 454         }
 455         return 0;
 456 }
 457
 458 void diff_free_filespec_data(struct diff_filespec *s)
 459 {
 460         if (s->should_free)
 461                 free(s->data);
 462         else if (s->should_munmap)
 463                 munmap(s->data, s->size);
 464         s->should_free = s->should_munmap = 0;
 465         s->data = NULL;
 466 }
 467
 468 static void prep_temp_blob(struct diff_tempfile *temp,
 469                            void *blob,
 470                            unsigned long size,
 471                            const unsigned char *sha1,
 472                            int mode)
 473 {
 474         int fd;
 475
 476         fd = git_mkstemp(temp->tmp_path, TEMPFILE_PATH_LEN, ".diff_XXXXXX");
 477         if (fd < 0)
 478                 die("unable to create temp-file");
 479         if (write(fd, blob, size) != size)
 480                 die("unable to write temp-file");
 481         close(fd);
 482         temp->name = temp->tmp_path;
 483         strcpy(temp->hex, sha1_to_hex(sha1));
 484         temp->hex[40] = 0;
 485         sprintf(temp->mode, "%06o", mode);
 486 }
 487
 488 static void prepare_temp_file(const char *name,
 489                               struct diff_tempfile *temp,
 490                               struct diff_filespec *one)
 491 {
 492         if (!DIFF_FILE_VALID(one)) {
 493         not_a_valid_file:
 494                 /* A '-' entry produces this for file-2, and
 495                  * a '+' entry produces this for file-1.
 496                  */
 497                 temp->name = "/dev/null";
 498                 strcpy(temp->hex, ".");
 499                 strcpy(temp->mode, ".");
 500                 return;
 501         }
 502
 503         if (!one->sha1_valid ||
 504             work_tree_matches(name, one->sha1)) {
 505                 struct stat st;
 506                 if (lstat(name, &st) < 0) {
 507                         if (errno == ENOENT)
 508                                 goto not_a_valid_file;
 509                         die("stat(%s): %s", name, strerror(errno));
 510                 }
 511                 if (S_ISLNK(st.st_mode)) {
 512                         int ret;
 513                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
 514                         if (sizeof(buf) <= st.st_size)
 515                                 die("symlink too long: %s", name);
 516                         ret = readlink(name, buf, st.st_size);
 517                         if (ret < 0)
 518                                 die("readlink(%s)", name);
 519                         prep_temp_blob(temp, buf, st.st_size,
 520                                        (one->sha1_valid ?
 521                                         one->sha1 : null_sha1),
 522                                        (one->sha1_valid ?
 523                                         one->mode : S_IFLNK));
 524                 }
 525                 else {
 526                         /* we can borrow from the file in the work tree */
 527                         temp->name = name;
 528                         if (!one->sha1_valid)
 529                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
 530                         else
 531                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
 532                         /* Even though we may sometimes borrow the
 533                          * contents from the work tree, we always want
 534                          * one->mode.  mode is trustworthy even when
 535                          * !(one->sha1_valid), as long as
 536                          * DIFF_FILE_VALID(one).
 537                          */
 538                         sprintf(temp->mode, "%06o", one->mode);
 539                 }
 540                 return;
 541         }
 542         else {
 543                 if (diff_populate_filespec(one, 0))
 544                         die("cannot read data blob for %s", one->path);
 545                 prep_temp_blob(temp, one->data, one->size,
 546                                one->sha1, one->mode);
 547         }
 548 }
 549
 550 static void remove_tempfile(void)
 551 {
 552         int i;
 553
 554         for (i = 0; i < 2; i++)
 555                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
 556                         unlink(diff_temp[i].name);
 557                         diff_temp[i].name = NULL;
 558                 }
 559 }
 560
 561 static void remove_tempfile_on_signal(int signo)
 562 {
 563         remove_tempfile();
 564         signal(SIGINT, SIG_DFL);
 565         raise(signo);
 566 }
 567
 568 static int spawn_prog(const char *pgm, const char **arg)
 569 {
 570         pid_t pid;
 571         int status;
 572
 573         fflush(NULL);
 574         pid = fork();
 575         if (pid < 0)
 576                 die("unable to fork");
 577         if (!pid) {
 578                 execvp(pgm, (char *const*) arg);
 579                 exit(255);
 580         }
 581
 582         while (waitpid(pid, &status, 0) < 0) {
 583                 if (errno == EINTR)
 584                         continue;
 585                 return -1;
 586         }
 587
 588         /* Earlier we did not check the exit status because
 589          * diff exits non-zero if files are different, and
 590          * we are not interested in knowing that.  It was a
 591          * mistake which made it harder to quit a diff-*
 592          * session that uses the git-apply-patch-script as
 593          * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
 594          * should also exit non-zero only when it wants to
 595          * abort the entire diff-* session.
 596          */
 597         if (WIFEXITED(status) && !WEXITSTATUS(status))
 598                 return 0;
 599         return -1;
 600 }
 601
 602 /* An external diff command takes:
 603  *
 604  * diff-cmd name infile1 infile1-sha1 infile1-mode \
 605  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
 606  *
 607  */
 608 static void run_external_diff(const char *pgm,
 609                               const char *name,
 610                               const char *other,
 611                               struct diff_filespec *one,
 612                               struct diff_filespec *two,
 613                               const char *xfrm_msg,
 614                               int complete_rewrite)
 615 {
 616         const char *spawn_arg[10];
 617         struct diff_tempfile *temp = diff_temp;
 618         int retval;
 619         static int atexit_asked = 0;
 620         const char *othername;
 621
 622         othername = (other? other : name);
 623         if (one && two) {
 624                 prepare_temp_file(name, &temp[0], one);
 625                 prepare_temp_file(othername, &temp[1], two);
 626                 if (! atexit_asked &&
 627                     (temp[0].name == temp[0].tmp_path ||
 628                      temp[1].name == temp[1].tmp_path)) {
 629                         atexit_asked = 1;
 630                         atexit(remove_tempfile);
 631                 }
 632                 signal(SIGINT, remove_tempfile_on_signal);
 633         }
 634
 635         if (pgm) {
 636                 const char **arg = &spawn_arg[0];
 637                 if (one && two) {
 638                         *arg++ = pgm;
 639                         *arg++ = name;
 640                         *arg++ = temp[0].name;
 641                         *arg++ = temp[0].hex;
 642                         *arg++ = temp[0].mode;
 643                         *arg++ = temp[1].name;
 644                         *arg++ = temp[1].hex;
 645                         *arg++ = temp[1].mode;
 646                         if (other) {
 647                                 *arg++ = other;
 648                                 *arg++ = xfrm_msg;
 649                         }
 650                 } else {
 651                         *arg++ = pgm;
 652                         *arg++ = name;
 653                 }
 654                 *arg = NULL;
 655         } else {
 656                 if (one && two) {
 657                         pgm = builtin_diff(name, othername, temp, xfrm_msg, complete_rewrite, spawn_arg);
 658                 } else
 659                         printf("* Unmerged path %s\n", name);
 660         }
 661
 662         retval = 0;
 663         if (pgm)
 664                 retval = spawn_prog(pgm, spawn_arg);
 665         remove_tempfile();
 666         if (retval) {
 667                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
 668                 exit(1);
 669         }
 670 }
 671
 672 static void diff_fill_sha1_info(struct diff_filespec *one)
 673 {
 674         if (DIFF_FILE_VALID(one)) {
 675                 if (!one->sha1_valid) {
 676                         struct stat st;
 677                         if (lstat(one->path, &st) < 0)
 678                                 die("stat %s", one->path);
 679                         if (index_path(one->sha1, one->path, &st, 0))
 680                                 die("cannot hash %s\n", one->path);
 681                 }
 682         }
 683         else
 684                 memset(one->sha1, 0, 20);
 685 }
 686
 687 static void run_diff(struct diff_filepair *p, struct diff_options *o)
 688 {
 689         const char *pgm = external_diff();
 690         char msg[PATH_MAX*2+300], *xfrm_msg;
 691         struct diff_filespec *one;
 692         struct diff_filespec *two;
 693         const char *name;
 694         const char *other;
 695         char *name_munged, *other_munged;
 696         int complete_rewrite = 0;
 697         int len;
 698
 699         if (DIFF_PAIR_UNMERGED(p)) {
 700                 /* unmerged */
 701                 run_external_diff(pgm, p->one->path, NULL, NULL, NULL, NULL,
 702                                   0);
 703                 return;
 704         }
 705
 706         name = p->one->path;
 707         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
 708         name_munged = quote_one(name);
 709         other_munged = quote_one(other);
 710         one = p->one; two = p->two;
 711
 712         diff_fill_sha1_info(one);
 713         diff_fill_sha1_info(two);
 714
 715         len = 0;
 716         switch (p->status) {
 717         case DIFF_STATUS_COPIED:
 718                 len += snprintf(msg + len, sizeof(msg) - len,
 719                                 "similarity index %d%%\n"
 720                                 "copy from %s\n"
 721                                 "copy to %s\n",
 722                                 (int)(0.5 + p->score * 100.0/MAX_SCORE),
 723                                 name_munged, other_munged);
 724                 break;
 725         case DIFF_STATUS_RENAMED:
 726                 len += snprintf(msg + len, sizeof(msg) - len,
 727                                 "similarity index %d%%\n"
 728                                 "rename from %s\n"
 729                                 "rename to %s\n",
 730                                 (int)(0.5 + p->score * 100.0/MAX_SCORE),
 731                                 name_munged, other_munged);
 732                 break;
 733         case DIFF_STATUS_MODIFIED:
 734                 if (p->score) {
 735                         len += snprintf(msg + len, sizeof(msg) - len,
 736                                         "dissimilarity index %d%%\n",
 737                                         (int)(0.5 + p->score *
 738                                               100.0/MAX_SCORE));
 739                         complete_rewrite = 1;
 740                         break;
 741                 }
 742                 /* fallthru */
 743         default:
 744                 /* nothing */
 745                 ;
 746         }
 747
 748         if (memcmp(one->sha1, two->sha1, 20)) {
 749                 char one_sha1[41];
 750                 int abbrev = o->full_index ? 40 : DEFAULT_ABBREV;
 751                 memcpy(one_sha1, sha1_to_hex(one->sha1), 41);
 752
 753                 len += snprintf(msg + len, sizeof(msg) - len,
 754                                 "index %.*s..%.*s",
 755                                 abbrev, one_sha1, abbrev,
 756                                 sha1_to_hex(two->sha1));
 757                 if (one->mode == two->mode)
 758                         len += snprintf(msg + len, sizeof(msg) - len,
 759                                         " %06o", one->mode);
 760                 len += snprintf(msg + len, sizeof(msg) - len, "\n");
 761         }
 762
 763         if (len)
 764                 msg[--len] = 0;
 765         xfrm_msg = len ? msg : NULL;
 766
 767         if (!pgm &&
 768             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
 769             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
 770                 /* a filepair that changes between file and symlink
 771                  * needs to be split into deletion and creation.
 772                  */
 773                 struct diff_filespec *null = alloc_filespec(two->path);
 774                 run_external_diff(NULL, name, other, one, null, xfrm_msg, 0);
 775                 free(null);
 776                 null = alloc_filespec(one->path);
 777                 run_external_diff(NULL, name, other, null, two, xfrm_msg, 0);
 778                 free(null);
 779         }
 780         else
 781                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
 782                                   complete_rewrite);
 783
 784         free(name_munged);
 785         free(other_munged);
 786 }
 787
 788 void diff_setup(struct diff_options *options)
 789 {
 790         memset(options, 0, sizeof(*options));
 791         options->output_format = DIFF_FORMAT_RAW;
 792         options->line_termination = '\n';
 793         options->break_opt = -1;
 794         options->rename_limit = -1;
 795
 796         options->change = diff_change;
 797         options->add_remove = diff_addremove;
 798 }
 799
 800 int diff_setup_done(struct diff_options *options)
 801 {
 802         if ((options->find_copies_harder &&
 803              options->detect_rename != DIFF_DETECT_COPY) ||
 804             (0 <= options->rename_limit && !options->detect_rename))
 805                 return -1;
 806         if (options->detect_rename && options->rename_limit < 0)
 807                 options->rename_limit = diff_rename_limit_default;
 808         if (options->setup & DIFF_SETUP_USE_CACHE) {
 809                 if (!active_cache)
 810                         /* read-cache does not die even when it fails
 811                          * so it is safe for us to do this here.  Also
 812                          * it does not smudge active_cache or active_nr
 813                          * when it fails, so we do not have to worry about
 814                          * cleaning it up ourselves either.
 815                          */
 816                         read_cache();
 817         }
 818         if (options->setup & DIFF_SETUP_USE_SIZE_CACHE)
 819                 use_size_cache = 1;
 820         if (options->abbrev <= 0 || 40 < options->abbrev)
 821                 options->abbrev = 40; /* full */
 822
 823         return 0;
 824 }
 825
 826 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 827 {
 828         const char *arg = av[0];
 829         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
 830                 options->output_format = DIFF_FORMAT_PATCH;
 831         else if (!strcmp(arg, "-z"))
 832                 options->line_termination = 0;
 833         else if (!strncmp(arg, "-l", 2))
 834                 options->rename_limit = strtoul(arg+2, NULL, 10);
 835         else if (!strcmp(arg, "--full-index"))
 836                 options->full_index = 1;
 837         else if (!strcmp(arg, "--name-only"))
 838                 options->output_format = DIFF_FORMAT_NAME;
 839         else if (!strcmp(arg, "--name-status"))
 840                 options->output_format = DIFF_FORMAT_NAME_STATUS;
 841         else if (!strcmp(arg, "-R"))
 842                 options->reverse_diff = 1;
 843         else if (!strncmp(arg, "-S", 2))
 844                 options->pickaxe = arg + 2;
 845         else if (!strcmp(arg, "-s"))
 846                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
 847         else if (!strncmp(arg, "-O", 2))
 848                 options->orderfile = arg + 2;
 849         else if (!strncmp(arg, "--diff-filter=", 14))
 850                 options->filter = arg + 14;
 851         else if (!strcmp(arg, "--pickaxe-all"))
 852                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
 853         else if (!strncmp(arg, "-B", 2)) {
 854                 if ((options->break_opt =
 855                      diff_scoreopt_parse(arg)) == -1)
 856                         return -1;
 857         }
 858         else if (!strncmp(arg, "-M", 2)) {
 859                 if ((options->rename_score =
 860                      diff_scoreopt_parse(arg)) == -1)
 861                         return -1;
 862                 options->detect_rename = DIFF_DETECT_RENAME;
 863         }
 864         else if (!strncmp(arg, "-C", 2)) {
 865                 if ((options->rename_score =
 866                      diff_scoreopt_parse(arg)) == -1)
 867                         return -1;
 868                 options->detect_rename = DIFF_DETECT_COPY;
 869         }
 870         else if (!strcmp(arg, "--find-copies-harder"))
 871                 options->find_copies_harder = 1;
 872         else if (!strcmp(arg, "--abbrev"))
 873                 options->abbrev = DEFAULT_ABBREV;
 874         else if (!strncmp(arg, "--abbrev=", 9)) {
 875                 options->abbrev = strtoul(arg + 9, NULL, 10);
 876                 if (options->abbrev < MINIMUM_ABBREV)
 877                         options->abbrev = MINIMUM_ABBREV;
 878                 else if (40 < options->abbrev)
 879                         options->abbrev = 40;
 880         }
 881         else
 882                 return 0;
 883         return 1;
 884 }
 885
 886 static int parse_num(const char **cp_p)
 887 {
 888         unsigned long num, scale;
 889         int ch, dot;
 890         const char *cp = *cp_p;
 891
 892         num = 0;
 893         scale = 1;
 894         dot = 0;
 895         for(;;) {
 896                 ch = *cp;
 897                 if ( !dot && ch == '.' ) {
 898                         scale = 1;
 899                         dot = 1;
 900                 } else if ( ch == '%' ) {
 901                         scale = dot ? scale*100 : 100;
 902                         cp++;   /* % is always at the end */
 903                         break;
 904                 } else if ( ch >= '0' && ch <= '9' ) {
 905                         if ( scale < 100000 ) {
 906                                 scale *= 10;
 907                                 num = (num*10) + (ch-'0');
 908                         }
 909                 } else {
 910                         break;
 911                 }
 912                 cp++;
 913         }
 914         *cp_p = cp;
 915
 916         /* user says num divided by scale and we say internally that
 917          * is MAX_SCORE * num / scale.
 918          */
 919         return (num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale);
 920 }
 921
 922 int diff_scoreopt_parse(const char *opt)
 923 {
 924         int opt1, opt2, cmd;
 925
 926         if (*opt++ != '-')
 927                 return -1;
 928         cmd = *opt++;
 929         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
 930                 return -1; /* that is not a -M, -C nor -B option */
 931
 932         opt1 = parse_num(&opt);
 933         if (cmd != 'B')
 934                 opt2 = 0;
 935         else {
 936                 if (*opt == 0)
 937                         opt2 = 0;
 938                 else if (*opt != '/')
 939                         return -1; /* we expect -B80/99 or -B80 */
 940                 else {
 941                         opt++;
 942                         opt2 = parse_num(&opt);
 943                 }
 944         }
 945         if (*opt != 0)
 946                 return -1;
 947         return opt1 | (opt2 << 16);
 948 }
 949
 950 struct diff_queue_struct diff_queued_diff;
 951
 952 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
 953 {
 954         if (queue->alloc <= queue->nr) {
 955                 queue->alloc = alloc_nr(queue->alloc);
 956                 queue->queue = xrealloc(queue->queue,
 957                                         sizeof(dp) * queue->alloc);
 958         }
 959         queue->queue[queue->nr++] = dp;
 960 }
 961
 962 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
 963                                  struct diff_filespec *one,
 964                                  struct diff_filespec *two)
 965 {
 966         struct diff_filepair *dp = xmalloc(sizeof(*dp));
 967         dp->one = one;
 968         dp->two = two;
 969         dp->score = 0;
 970         dp->status = 0;
 971         dp->source_stays = 0;
 972         dp->broken_pair = 0;
 973         if (queue)
 974                 diff_q(queue, dp);
 975         return dp;
 976 }
 977
 978 void diff_free_filepair(struct diff_filepair *p)
 979 {
 980         diff_free_filespec_data(p->one);
 981         diff_free_filespec_data(p->two);
 982         free(p->one);
 983         free(p->two);
 984         free(p);
 985 }
 986
 987 /* This is different from find_unique_abbrev() in that
 988  * it stuffs the result with dots for alignment.
 989  */
 990 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
 991 {
 992         int abblen;
 993         const char *abbrev;
 994         if (len == 40)
 995                 return sha1_to_hex(sha1);
 996
 997         abbrev = find_unique_abbrev(sha1, len);
 998         if (!abbrev)
 999                 return sha1_to_hex(sha1);
1000         abblen = strlen(abbrev);
1001         if (abblen < 37) {
1002                 static char hex[41];
1003                 if (len < abblen && abblen <= len + 2)
1004                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
1005                 else
1006                         sprintf(hex, "%s...", abbrev);
1007                 return hex;
1008         }
1009         return sha1_to_hex(sha1);
1010 }
1011
1012 static void diff_flush_raw(struct diff_filepair *p,
1013                            int line_termination,
1014                            int inter_name_termination,
1015                            struct diff_options *options)
1016 {
1017         int two_paths;
1018         char status[10];
1019         int abbrev = options->abbrev;
1020         const char *path_one, *path_two;
1021         int output_format = options->output_format;
1022
1023         path_one = p->one->path;
1024         path_two = p->two->path;
1025         if (line_termination) {
1026                 path_one = quote_one(path_one);
1027                 path_two = quote_one(path_two);
1028         }
1029
1030         if (p->score)
1031                 sprintf(status, "%c%03d", p->status,
1032                         (int)(0.5 + p->score * 100.0/MAX_SCORE));
1033         else {
1034                 status[0] = p->status;
1035                 status[1] = 0;
1036         }
1037         switch (p->status) {
1038         case DIFF_STATUS_COPIED:
1039         case DIFF_STATUS_RENAMED:
1040                 two_paths = 1;
1041                 break;
1042         case DIFF_STATUS_ADDED:
1043         case DIFF_STATUS_DELETED:
1044                 two_paths = 0;
1045                 break;
1046         default:
1047                 two_paths = 0;
1048                 break;
1049         }
1050         if (output_format != DIFF_FORMAT_NAME_STATUS) {
1051                 printf(":%06o %06o %s ",
1052                        p->one->mode, p->two->mode,
1053                        diff_unique_abbrev(p->one->sha1, abbrev));
1054                 printf("%s ",
1055                        diff_unique_abbrev(p->two->sha1, abbrev));
1056         }
1057         printf("%s%c%s", status, inter_name_termination, path_one);
1058         if (two_paths)
1059                 printf("%c%s", inter_name_termination, path_two);
1060         putchar(line_termination);
1061         if (path_one != p->one->path)
1062                 free((void*)path_one);
1063         if (path_two != p->two->path)
1064                 free((void*)path_two);
1065 }
1066
1067 static void diff_flush_name(struct diff_filepair *p,
1068                             int inter_name_termination,
1069                             int line_termination)
1070 {
1071         char *path = p->two->path;
1072
1073         if (line_termination)
1074                 path = quote_one(p->two->path);
1075         else
1076                 path = p->two->path;
1077         printf("%s%c", path, line_termination);
1078         if (p->two->path != path)
1079                 free(path);
1080 }
1081
1082 int diff_unmodified_pair(struct diff_filepair *p)
1083 {
1084         /* This function is written stricter than necessary to support
1085          * the currently implemented transformers, but the idea is to
1086          * let transformers to produce diff_filepairs any way they want,
1087          * and filter and clean them up here before producing the output.
1088          */
1089         struct diff_filespec *one, *two;
1090
1091         if (DIFF_PAIR_UNMERGED(p))
1092                 return 0; /* unmerged is interesting */
1093
1094         one = p->one;
1095         two = p->two;
1096
1097         /* deletion, addition, mode or type change
1098          * and rename are all interesting.
1099          */
1100         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
1101             DIFF_PAIR_MODE_CHANGED(p) ||
1102             strcmp(one->path, two->path))
1103                 return 0;
1104
1105         /* both are valid and point at the same path.  that is, we are
1106          * dealing with a change.
1107          */
1108         if (one->sha1_valid && two->sha1_valid &&
1109             !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
1110                 return 1; /* no change */
1111         if (!one->sha1_valid && !two->sha1_valid)
1112                 return 1; /* both look at the same file on the filesystem. */
1113         return 0;
1114 }
1115
1116 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
1117 {
1118         if (diff_unmodified_pair(p))
1119                 return;
1120
1121         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1122             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1123                 return; /* no tree diffs in patch format */
1124
1125         run_diff(p, o);
1126 }
1127
1128 int diff_queue_is_empty(void)
1129 {
1130         struct diff_queue_struct *q = &diff_queued_diff;
1131         int i;
1132         for (i = 0; i < q->nr; i++)
1133                 if (!diff_unmodified_pair(q->queue[i]))
1134                         return 0;
1135         return 1;
1136 }
1137
1138 #if DIFF_DEBUG
1139 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
1140 {
1141         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
1142                 x, one ? one : "",
1143                 s->path,
1144                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
1145                 s->mode,
1146                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
1147         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
1148                 x, one ? one : "",
1149                 s->size, s->xfrm_flags);
1150 }
1151
1152 void diff_debug_filepair(const struct diff_filepair *p, int i)
1153 {
1154         diff_debug_filespec(p->one, i, "one");
1155         diff_debug_filespec(p->two, i, "two");
1156         fprintf(stderr, "score %d, status %c stays %d broken %d\n",
1157                 p->score, p->status ? p->status : '?',
1158                 p->source_stays, p->broken_pair);
1159 }
1160
1161 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
1162 {
1163         int i;
1164         if (msg)
1165                 fprintf(stderr, "%s\n", msg);
1166         fprintf(stderr, "q->nr = %d\n", q->nr);
1167         for (i = 0; i < q->nr; i++) {
1168                 struct diff_filepair *p = q->queue[i];
1169                 diff_debug_filepair(p, i);
1170         }
1171 }
1172 #endif
1173
1174 static void diff_resolve_rename_copy(void)
1175 {
1176         int i, j;
1177         struct diff_filepair *p, *pp;
1178         struct diff_queue_struct *q = &diff_queued_diff;
1179
1180         diff_debug_queue("resolve-rename-copy", q);
1181
1182         for (i = 0; i < q->nr; i++) {
1183                 p = q->queue[i];
1184                 p->status = 0; /* undecided */
1185                 if (DIFF_PAIR_UNMERGED(p))
1186                         p->status = DIFF_STATUS_UNMERGED;
1187                 else if (!DIFF_FILE_VALID(p->one))
1188                         p->status = DIFF_STATUS_ADDED;
1189                 else if (!DIFF_FILE_VALID(p->two))
1190                         p->status = DIFF_STATUS_DELETED;
1191                 else if (DIFF_PAIR_TYPE_CHANGED(p))
1192                         p->status = DIFF_STATUS_TYPE_CHANGED;
1193
1194                 /* from this point on, we are dealing with a pair
1195                  * whose both sides are valid and of the same type, i.e.
1196                  * either in-place edit or rename/copy edit.
1197                  */
1198                 else if (DIFF_PAIR_RENAME(p)) {
1199                         if (p->source_stays) {
1200                                 p->status = DIFF_STATUS_COPIED;
1201                                 continue;
1202                         }
1203                         /* See if there is some other filepair that
1204                          * copies from the same source as us.  If so
1205                          * we are a copy.  Otherwise we are either a
1206                          * copy if the path stays, or a rename if it
1207                          * does not, but we already handled "stays" case.
1208                          */
1209                         for (j = i + 1; j < q->nr; j++) {
1210                                 pp = q->queue[j];
1211                                 if (strcmp(pp->one->path, p->one->path))
1212                                         continue; /* not us */
1213                                 if (!DIFF_PAIR_RENAME(pp))
1214                                         continue; /* not a rename/copy */
1215                                 /* pp is a rename/copy from the same source */
1216                                 p->status = DIFF_STATUS_COPIED;
1217                                 break;
1218                         }
1219                         if (!p->status)
1220                                 p->status = DIFF_STATUS_RENAMED;
1221                 }
1222                 else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
1223                          p->one->mode != p->two->mode)
1224                         p->status = DIFF_STATUS_MODIFIED;
1225                 else {
1226                         /* This is a "no-change" entry and should not
1227                          * happen anymore, but prepare for broken callers.
1228                          */
1229                         error("feeding unmodified %s to diffcore",
1230                               p->one->path);
1231                         p->status = DIFF_STATUS_UNKNOWN;
1232                 }
1233         }
1234         diff_debug_queue("resolve-rename-copy done", q);
1235 }
1236
1237 void diff_flush(struct diff_options *options)
1238 {
1239         struct diff_queue_struct *q = &diff_queued_diff;
1240         int i;
1241         int inter_name_termination = '\t';
1242         int diff_output_format = options->output_format;
1243         int line_termination = options->line_termination;
1244
1245         if (!line_termination)
1246                 inter_name_termination = 0;
1247
1248         for (i = 0; i < q->nr; i++) {
1249                 struct diff_filepair *p = q->queue[i];
1250                 if ((diff_output_format == DIFF_FORMAT_NO_OUTPUT) ||
1251                     (p->status == DIFF_STATUS_UNKNOWN))
1252                         continue;
1253                 if (p->status == 0)
1254                         die("internal error in diff-resolve-rename-copy");
1255                 switch (diff_output_format) {
1256                 case DIFF_FORMAT_PATCH:
1257                         diff_flush_patch(p, options);
1258                         break;
1259                 case DIFF_FORMAT_RAW:
1260                 case DIFF_FORMAT_NAME_STATUS:
1261                         diff_flush_raw(p, line_termination,
1262                                        inter_name_termination,
1263                                        options);
1264                         break;
1265                 case DIFF_FORMAT_NAME:
1266                         diff_flush_name(p,
1267                                         inter_name_termination,
1268                                         line_termination);
1269                         break;
1270                 }
1271                 diff_free_filepair(q->queue[i]);
1272         }
1273         free(q->queue);
1274         q->queue = NULL;
1275         q->nr = q->alloc = 0;
1276 }
1277
1278 static void diffcore_apply_filter(const char *filter)
1279 {
1280         int i;
1281         struct diff_queue_struct *q = &diff_queued_diff;
1282         struct diff_queue_struct outq;
1283         outq.queue = NULL;
1284         outq.nr = outq.alloc = 0;
1285
1286         if (!filter)
1287                 return;
1288
1289         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
1290                 int found;
1291                 for (i = found = 0; !found && i < q->nr; i++) {
1292                         struct diff_filepair *p = q->queue[i];
1293                         if (((p->status == DIFF_STATUS_MODIFIED) &&
1294                              ((p->score &&
1295                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
1296                               (!p->score &&
1297                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
1298                             ((p->status != DIFF_STATUS_MODIFIED) &&
1299                              strchr(filter, p->status)))
1300                                 found++;
1301                 }
1302                 if (found)
1303                         return;
1304
1305                 /* otherwise we will clear the whole queue
1306                  * by copying the empty outq at the end of this
1307                  * function, but first clear the current entries
1308                  * in the queue.
1309                  */
1310                 for (i = 0; i < q->nr; i++)
1311                         diff_free_filepair(q->queue[i]);
1312         }
1313         else {
1314                 /* Only the matching ones */
1315                 for (i = 0; i < q->nr; i++) {
1316                         struct diff_filepair *p = q->queue[i];
1317
1318                         if (((p->status == DIFF_STATUS_MODIFIED) &&
1319                              ((p->score &&
1320                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
1321                               (!p->score &&
1322                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
1323                             ((p->status != DIFF_STATUS_MODIFIED) &&
1324                              strchr(filter, p->status)))
1325                                 diff_q(&outq, p);
1326                         else
1327                                 diff_free_filepair(p);
1328                 }
1329         }
1330         free(q->queue);
1331         *q = outq;
1332 }
1333
1334 void diffcore_std(struct diff_options *options)
1335 {
1336         if (options->paths && options->paths[0])
1337                 diffcore_pathspec(options->paths);
1338         if (options->break_opt != -1)
1339                 diffcore_break(options->break_opt);
1340         if (options->detect_rename)
1341                 diffcore_rename(options);
1342         if (options->break_opt != -1)
1343                 diffcore_merge_broken();
1344         if (options->pickaxe)
1345                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
1346         if (options->orderfile)
1347                 diffcore_order(options->orderfile);
1348         diff_resolve_rename_copy();
1349         diffcore_apply_filter(options->filter);
1350 }
1351
1352
1353 void diffcore_std_no_resolve(struct diff_options *options)
1354 {
1355         if (options->pickaxe)
1356                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
1357         if (options->orderfile)
1358                 diffcore_order(options->orderfile);
1359         diffcore_apply_filter(options->filter);
1360 }
1361
1362 void diff_addremove(struct diff_options *options,
1363                     int addremove, unsigned mode,
1364                     const unsigned char *sha1,
1365                     const char *base, const char *path)
1366 {
1367         char concatpath[PATH_MAX];
1368         struct diff_filespec *one, *two;
1369
1370         /* This may look odd, but it is a preparation for
1371          * feeding "there are unchanged files which should
1372          * not produce diffs, but when you are doing copy
1373          * detection you would need them, so here they are"
1374          * entries to the diff-core.  They will be prefixed
1375          * with something like '=' or '*' (I haven't decided
1376          * which but should not make any difference).
1377          * Feeding the same new and old to diff_change()
1378          * also has the same effect.
1379          * Before the final output happens, they are pruned after
1380          * merged into rename/copy pairs as appropriate.
1381          */
1382         if (options->reverse_diff)
1383                 addremove = (addremove == '+' ? '-' :
1384                              addremove == '-' ? '+' : addremove);
1385
1386         if (!path) path = "";
1387         sprintf(concatpath, "%s%s", base, path);
1388         one = alloc_filespec(concatpath);
1389         two = alloc_filespec(concatpath);
1390
1391         if (addremove != '+')
1392                 fill_filespec(one, sha1, mode);
1393         if (addremove != '-')
1394                 fill_filespec(two, sha1, mode);
1395
1396         diff_queue(&diff_queued_diff, one, two);
1397 }
1398
1399 void diff_change(struct diff_options *options,
1400                  unsigned old_mode, unsigned new_mode,
1401                  const unsigned char *old_sha1,
1402                  const unsigned char *new_sha1,
1403                  const char *base, const char *path)
1404 {
1405         char concatpath[PATH_MAX];
1406         struct diff_filespec *one, *two;
1407
1408         if (options->reverse_diff) {
1409                 unsigned tmp;
1410                 const unsigned char *tmp_c;
1411                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
1412                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
1413         }
1414         if (!path) path = "";
1415         sprintf(concatpath, "%s%s", base, path);
1416         one = alloc_filespec(concatpath);
1417         two = alloc_filespec(concatpath);
1418         fill_filespec(one, old_sha1, old_mode);
1419         fill_filespec(two, new_sha1, new_mode);
1420
1421         diff_queue(&diff_queued_diff, one, two);
1422 }
1423
1424 void diff_unmerge(struct diff_options *options,
1425                   const char *path)
1426 {
1427         struct diff_filespec *one, *two;
1428         one = alloc_filespec(path);
1429         two = alloc_filespec(path);
1430         diff_queue(&diff_queued_diff, one, two);
1431 }