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 <limits.h>
   8 #include "cache.h"
   9 #include "diff.h"
  10 #include "diffcore.h"
  11
  12 static const char *diff_opts = "-pu";
  13 static unsigned char null_sha1[20] = { 0, };
  14
  15 static int detect_rename;
  16 static int reverse_diff;
  17 static int diff_raw_output = -1;
  18 static const char **pathspec;
  19 static int speccnt;
  20 static int minimum_score;
  21
  22 static const char *external_diff(void)
  23 {
  24         static const char *external_diff_cmd = NULL;
  25         static int done_preparing = 0;
  26
  27         if (done_preparing)
  28                 return external_diff_cmd;
  29
  30         /*
  31          * Default values above are meant to match the
  32          * Linux kernel development style.  Examples of
  33          * alternative styles you can specify via environment
  34          * variables are:
  35          *
  36          * GIT_DIFF_OPTS="-c";
  37          */
  38         if (gitenv("GIT_EXTERNAL_DIFF"))
  39                 external_diff_cmd = gitenv("GIT_EXTERNAL_DIFF");
  40
  41         /* In case external diff fails... */
  42         diff_opts = gitenv("GIT_DIFF_OPTS") ? : diff_opts;
  43
  44         done_preparing = 1;
  45         return external_diff_cmd;
  46 }
  47
  48 /* Help to copy the thing properly quoted for the shell safety.
  49  * any single quote is replaced with '\'', and the caller is
  50  * expected to enclose the result within a single quote pair.
  51  *
  52  * E.g.
  53  *  original     sq_expand     result
  54  *  name     ==> name      ==> 'name'
  55  *  a b      ==> a b       ==> 'a b'
  56  *  a'b      ==> a'\''b    ==> 'a'\''b'
  57  */
  58 static char *sq_expand(const char *src)
  59 {
  60         static char *buf = NULL;
  61         int cnt, c;
  62         const char *cp;
  63         char *bp;
  64
  65         /* count bytes needed to store the quoted string. */
  66         for (cnt = 1, cp = src; *cp; cnt++, cp++)
  67                 if (*cp == '\'')
  68                         cnt += 3;
  69
  70         buf = xmalloc(cnt);
  71         bp = buf;
  72         while ((c = *src++)) {
  73                 if (c != '\'')
  74                         *bp++ = c;
  75                 else {
  76                         bp = strcpy(bp, "'\\''");
  77                         bp += 4;
  78                 }
  79         }
  80         *bp = 0;
  81         return buf;
  82 }
  83
  84 static struct diff_tempfile {
  85         const char *name; /* filename external diff should read from */
  86         char hex[41];
  87         char mode[10];
  88         char tmp_path[50];
  89 } diff_temp[2];
  90
  91 static void builtin_diff(const char *name_a,
  92                          const char *name_b,
  93                          struct diff_tempfile *temp,
  94                          const char *xfrm_msg)
  95 {
  96         int i, next_at, cmd_size;
  97         const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
  98         const char *diff_arg  = "'%s' '%s'||:"; /* "||:" is to return 0 */
  99         const char *input_name_sq[2];
 100         const char *path0[2];
 101         const char *path1[2];
 102         const char *name_sq[2];
 103         char *cmd;
 104
 105         name_sq[0] = sq_expand(name_a);
 106         name_sq[1] = sq_expand(name_b);
 107
 108         /* diff_cmd and diff_arg have 6 %s in total which makes
 109          * the sum of these strings 12 bytes larger than required.
 110          * we use 2 spaces around diff-opts, and we need to count
 111          * terminating NUL, so we subtract 9 here.
 112          */
 113         cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
 114                         strlen(diff_arg) - 9);
 115         for (i = 0; i < 2; i++) {
 116                 input_name_sq[i] = sq_expand(temp[i].name);
 117                 if (!strcmp(temp[i].name, "/dev/null")) {
 118                         path0[i] = "/dev/null";
 119                         path1[i] = "";
 120                 } else {
 121                         path0[i] = i ? "b/" : "a/";
 122                         path1[i] = name_sq[i];
 123                 }
 124                 cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
 125                              strlen(input_name_sq[i]));
 126         }
 127
 128         cmd = xmalloc(cmd_size);
 129
 130         next_at = 0;
 131         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 132                             diff_cmd,
 133                             path0[0], path1[0], path0[1], path1[1]);
 134         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 135                             " %s ", diff_opts);
 136         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 137                             diff_arg, input_name_sq[0], input_name_sq[1]);
 138
 139         printf("diff --git a/%s b/%s\n", name_a, name_b);
 140         if (!path1[0][0])
 141                 printf("new file mode %s\n", temp[1].mode);
 142         else if (!path1[1][0])
 143                 printf("deleted file mode %s\n", temp[0].mode);
 144         else {
 145                 if (strcmp(temp[0].mode, temp[1].mode)) {
 146                         printf("old mode %s\n", temp[0].mode);
 147                         printf("new mode %s\n", temp[1].mode);
 148                 }
 149                 if (xfrm_msg && xfrm_msg[0])
 150                         fputs(xfrm_msg, stdout);
 151
 152                 if (strncmp(temp[0].mode, temp[1].mode, 3))
 153                         /* we do not run diff between different kind
 154                          * of objects.
 155                          */
 156                         exit(0);
 157         }
 158         fflush(NULL);
 159         execlp("/bin/sh","sh", "-c", cmd, NULL);
 160 }
 161
 162 struct diff_filespec *alloc_filespec(const char *path)
 163 {
 164         int namelen = strlen(path);
 165         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
 166         spec->path = (char *)(spec + 1);
 167         strcpy(spec->path, path);
 168         spec->should_free = spec->should_munmap = spec->file_valid = 0;
 169         spec->xfrm_flags = 0;
 170         spec->size = 0;
 171         spec->data = 0;
 172         return spec;
 173 }
 174
 175 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 176                    unsigned short mode)
 177 {
 178         spec->mode = mode;
 179         memcpy(spec->sha1, sha1, 20);
 180         spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
 181         spec->file_valid = 1;
 182 }
 183
 184 /*
 185  * Given a name and sha1 pair, if the dircache tells us the file in
 186  * the work tree has that object contents, return true, so that
 187  * prepare_temp_file() does not have to inflate and extract.
 188  */
 189 static int work_tree_matches(const char *name, const unsigned char *sha1)
 190 {
 191         struct cache_entry *ce;
 192         struct stat st;
 193         int pos, len;
 194
 195         /* We do not read the cache ourselves here, because the
 196          * benchmark with my previous version that always reads cache
 197          * shows that it makes things worse for diff-tree comparing
 198          * two linux-2.6 kernel trees in an already checked out work
 199          * tree.  This is because most diff-tree comparisons deal with
 200          * only a small number of files, while reading the cache is
 201          * expensive for a large project, and its cost outweighs the
 202          * savings we get by not inflating the object to a temporary
 203          * file.  Practically, this code only helps when we are used
 204          * by diff-cache --cached, which does read the cache before
 205          * calling us.
 206          */
 207         if (!active_cache)
 208                 return 0;
 209
 210         len = strlen(name);
 211         pos = cache_name_pos(name, len);
 212         if (pos < 0)
 213                 return 0;
 214         ce = active_cache[pos];
 215         if ((lstat(name, &st) < 0) ||
 216             !S_ISREG(st.st_mode) || /* careful! */
 217             ce_match_stat(ce, &st) ||
 218             memcmp(sha1, ce->sha1, 20))
 219                 return 0;
 220         /* we return 1 only when we can stat, it is a regular file,
 221          * stat information matches, and sha1 recorded in the cache
 222          * matches.  I.e. we know the file in the work tree really is
 223          * the same as the <name, sha1> pair.
 224          */
 225         return 1;
 226 }
 227
 228 /*
 229  * While doing rename detection and pickaxe operation, we may need to
 230  * grab the data for the blob (or file) for our own in-core comparison.
 231  * diff_filespec has data and size fields for this purpose.
 232  */
 233 int diff_populate_filespec(struct diff_filespec *s)
 234 {
 235         int err = 0;
 236         if (!s->file_valid)
 237                 die("internal error: asking to populate invalid file.");
 238         if (S_ISDIR(s->mode))
 239                 return -1;
 240
 241         if (s->data)
 242                 return err;
 243         if (!s->sha1_valid ||
 244             work_tree_matches(s->path, s->sha1)) {
 245                 struct stat st;
 246                 int fd;
 247                 if (lstat(s->path, &st) < 0) {
 248                         if (errno == ENOENT) {
 249                         err_empty:
 250                                 err = -1;
 251                         empty:
 252                                 s->data = "";
 253                                 s->size = 0;
 254                                 return err;
 255                         }
 256                 }
 257                 s->size = st.st_size;
 258                 if (!s->size)
 259                         goto empty;
 260                 if (S_ISLNK(st.st_mode)) {
 261                         int ret;
 262                         s->data = xmalloc(s->size);
 263                         s->should_free = 1;
 264                         ret = readlink(s->path, s->data, s->size);
 265                         if (ret < 0) {
 266                                 free(s->data);
 267                                 goto err_empty;
 268                         }
 269                         return 0;
 270                 }
 271                 fd = open(s->path, O_RDONLY);
 272                 if (fd < 0)
 273                         goto err_empty;
 274                 s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
 275                 s->should_munmap = 1;
 276                 close(fd);
 277         }
 278         else {
 279                 char type[20];
 280                 s->data = read_sha1_file(s->sha1, type, &s->size);
 281                 s->should_free = 1;
 282         }
 283         return 0;
 284 }
 285
 286 void diff_free_filespec_data(struct diff_filespec *s)
 287 {
 288         if (s->should_free)
 289                 free(s->data);
 290         else if (s->should_munmap)
 291                 munmap(s->data, s->size);
 292         s->should_free = s->should_munmap = 0;
 293         s->data = 0;
 294 }
 295
 296 static void prep_temp_blob(struct diff_tempfile *temp,
 297                            void *blob,
 298                            unsigned long size,
 299                            unsigned char *sha1,
 300                            int mode)
 301 {
 302         int fd;
 303
 304         strcpy(temp->tmp_path, ".diff_XXXXXX");
 305         fd = mkstemp(temp->tmp_path);
 306         if (fd < 0)
 307                 die("unable to create temp-file");
 308         if (write(fd, blob, size) != size)
 309                 die("unable to write temp-file");
 310         close(fd);
 311         temp->name = temp->tmp_path;
 312         strcpy(temp->hex, sha1_to_hex(sha1));
 313         temp->hex[40] = 0;
 314         sprintf(temp->mode, "%06o", mode);
 315 }
 316
 317 static void prepare_temp_file(const char *name,
 318                               struct diff_tempfile *temp,
 319                               struct diff_filespec *one)
 320 {
 321         if (!one->file_valid) {
 322         not_a_valid_file:
 323                 /* A '-' entry produces this for file-2, and
 324                  * a '+' entry produces this for file-1.
 325                  */
 326                 temp->name = "/dev/null";
 327                 strcpy(temp->hex, ".");
 328                 strcpy(temp->mode, ".");
 329                 return;
 330         }
 331
 332         if (!one->sha1_valid ||
 333             work_tree_matches(name, one->sha1)) {
 334                 struct stat st;
 335                 if (lstat(name, &st) < 0) {
 336                         if (errno == ENOENT)
 337                                 goto not_a_valid_file;
 338                         die("stat(%s): %s", name, strerror(errno));
 339                 }
 340                 if (S_ISLNK(st.st_mode)) {
 341                         int ret;
 342                         char *buf, buf_[1024];
 343                         buf = ((sizeof(buf_) < st.st_size) ?
 344                                xmalloc(st.st_size) : buf_);
 345                         ret = readlink(name, buf, st.st_size);
 346                         if (ret < 0)
 347                                 die("readlink(%s)", name);
 348                         prep_temp_blob(temp, buf, st.st_size,
 349                                        (one->sha1_valid ?
 350                                         one->sha1 : null_sha1),
 351                                        (one->sha1_valid ?
 352                                         one->mode : S_IFLNK));
 353                 }
 354                 else {
 355                         /* we can borrow from the file in the work tree */
 356                         temp->name = name;
 357                         if (!one->sha1_valid)
 358                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
 359                         else
 360                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
 361                         sprintf(temp->mode, "%06o",
 362                                 S_IFREG |ce_permissions(st.st_mode));
 363                 }
 364                 return;
 365         }
 366         else {
 367                 if (diff_populate_filespec(one))
 368                         die("cannot read data blob for %s", one->path);
 369                 prep_temp_blob(temp, one->data, one->size,
 370                                one->sha1, one->mode);
 371         }
 372 }
 373
 374 static void remove_tempfile(void)
 375 {
 376         int i;
 377
 378         for (i = 0; i < 2; i++)
 379                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
 380                         unlink(diff_temp[i].name);
 381                         diff_temp[i].name = NULL;
 382                 }
 383 }
 384
 385 static void remove_tempfile_on_signal(int signo)
 386 {
 387         remove_tempfile();
 388 }
 389
 390 static int matches_pathspec(const char *name)
 391 {
 392         int i;
 393         int namelen;
 394
 395         if (speccnt == 0)
 396                 return 1;
 397
 398         namelen = strlen(name);
 399         for (i = 0; i < speccnt; i++) {
 400                 int speclen = strlen(pathspec[i]);
 401                 if (! strncmp(pathspec[i], name, speclen) &&
 402                     speclen <= namelen &&
 403                     (name[speclen] == 0 || name[speclen] == '/'))
 404                         return 1;
 405         }
 406         return 0;
 407 }
 408
 409 /* An external diff command takes:
 410  *
 411  * diff-cmd name infile1 infile1-sha1 infile1-mode \
 412  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
 413  *
 414  */
 415 static void run_external_diff(const char *name,
 416                               const char *other,
 417                               struct diff_filespec *one,
 418                               struct diff_filespec *two,
 419                               const char *xfrm_msg)
 420 {
 421         struct diff_tempfile *temp = diff_temp;
 422         pid_t pid;
 423         int status;
 424         static int atexit_asked = 0;
 425
 426         if (!matches_pathspec(name) && (!other || !matches_pathspec(other)))
 427                 return;
 428
 429         if (one && two) {
 430                 prepare_temp_file(name, &temp[0], one);
 431                 prepare_temp_file(other ? : name, &temp[1], two);
 432                 if (! atexit_asked &&
 433                     (temp[0].name == temp[0].tmp_path ||
 434                      temp[1].name == temp[1].tmp_path)) {
 435                         atexit_asked = 1;
 436                         atexit(remove_tempfile);
 437                 }
 438                 signal(SIGINT, remove_tempfile_on_signal);
 439         }
 440
 441         fflush(NULL);
 442         pid = fork();
 443         if (pid < 0)
 444                 die("unable to fork");
 445         if (!pid) {
 446                 const char *pgm = external_diff();
 447                 if (pgm) {
 448                         if (one && two) {
 449                                 const char *exec_arg[10];
 450                                 const char **arg = &exec_arg[0];
 451                                 *arg++ = pgm;
 452                                 *arg++ = name;
 453                                 *arg++ = temp[0].name;
 454                                 *arg++ = temp[0].hex;
 455                                 *arg++ = temp[0].mode;
 456                                 *arg++ = temp[1].name;
 457                                 *arg++ = temp[1].hex;
 458                                 *arg++ = temp[1].mode;
 459                                 if (other) {
 460                                         *arg++ = other;
 461                                         *arg++ = xfrm_msg;
 462                                 }
 463                                 *arg = 0;
 464                                 execvp(pgm, (char *const*) exec_arg);
 465                         }
 466                         else
 467                                 execlp(pgm, pgm, name, NULL);
 468                 }
 469                 /*
 470                  * otherwise we use the built-in one.
 471                  */
 472                 if (one && two)
 473                         builtin_diff(name, other ? : name, temp, xfrm_msg);
 474                 else
 475                         printf("* Unmerged path %s\n", name);
 476                 exit(0);
 477         }
 478         if (waitpid(pid, &status, 0) < 0 ||
 479             !WIFEXITED(status) || WEXITSTATUS(status)) {
 480                 /* Earlier we did not check the exit status because
 481                  * diff exits non-zero if files are different, and
 482                  * we are not interested in knowing that.  It was a
 483                  * mistake which made it harder to quit a diff-*
 484                  * session that uses the git-apply-patch-script as
 485                  * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
 486                  * should also exit non-zero only when it wants to
 487                  * abort the entire diff-* session.
 488                  */
 489                 remove_tempfile();
 490                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
 491                 exit(1);
 492         }
 493         remove_tempfile();
 494 }
 495
 496 int diff_scoreopt_parse(const char *opt)
 497 {
 498         int diglen, num, scale, i;
 499         if (opt[0] != '-' || (opt[1] != 'M' && opt[1] != 'C'))
 500                 return -1; /* that is not a -M nor -C option */
 501         diglen = strspn(opt+2, "0123456789");
 502         if (diglen == 0 || strlen(opt+2) != diglen)
 503                 return 0; /* use default */
 504         sscanf(opt+2, "%d", &num);
 505         for (i = 0, scale = 1; i < diglen; i++)
 506                 scale *= 10;
 507
 508         /* user says num divided by scale and we say internally that
 509          * is MAX_SCORE * num / scale.
 510          */
 511         return MAX_SCORE * num / scale;
 512 }
 513
 514 void diff_setup(int detect_rename_, int minimum_score_, int reverse_diff_,
 515                 int diff_raw_output_,
 516                 const char **pathspec_, int speccnt_)
 517 {
 518         detect_rename = detect_rename_;
 519         reverse_diff = reverse_diff_;
 520         pathspec = pathspec_;
 521         diff_raw_output = diff_raw_output_;
 522         speccnt = speccnt_;
 523         minimum_score = minimum_score_ ? : DEFAULT_MINIMUM_SCORE;
 524 }
 525
 526 static struct diff_queue_struct queued_diff;
 527
 528 struct diff_file_pair *diff_queue(struct diff_queue_struct *queue,
 529                                   struct diff_filespec *one,
 530                                   struct diff_filespec *two)
 531 {
 532         struct diff_file_pair *dp = xmalloc(sizeof(*dp));
 533         dp->one = one;
 534         dp->two = two;
 535         dp->xfrm_msg = 0;
 536         dp->orig_order = queue->nr;
 537         dp->xfrm_work = 0;
 538         if (queue->alloc <= queue->nr) {
 539                 queue->alloc = alloc_nr(queue->alloc);
 540                 queue->queue = xrealloc(queue->queue,
 541                                        sizeof(dp) * queue->alloc);
 542         }
 543         queue->queue[queue->nr++] = dp;
 544         return dp;
 545 }
 546
 547 static const char *git_object_type(unsigned mode)
 548 {
 549         return S_ISDIR(mode) ? "tree" : "blob";
 550 }
 551
 552 static void diff_flush_raw(struct diff_file_pair *p)
 553 {
 554         struct diff_filespec *it;
 555         int addremove;
 556
 557         /* raw output does not have a way to express rename nor copy */
 558         if (strcmp(p->one->path, p->two->path))
 559                 return;
 560
 561         if (p->one->file_valid && p->two->file_valid) {
 562                 char hex[41];
 563                 strcpy(hex, sha1_to_hex(p->one->sha1));
 564                 printf("*%06o->%06o %s %s->%s %s%c",
 565                        p->one->mode, p->two->mode,
 566                        git_object_type(p->one->mode),
 567                        hex, sha1_to_hex(p->two->sha1),
 568                        p->one->path, diff_raw_output);
 569                 return;
 570         }
 571
 572         if (p->one->file_valid) {
 573                 it = p->one;
 574                 addremove = '-';
 575         } else {
 576                 it = p->two;
 577                 addremove = '+';
 578         }
 579
 580         printf("%c%06o %s %s %s%c",
 581                addremove,
 582                it->mode, git_object_type(it->mode),
 583                sha1_to_hex(it->sha1), it->path, diff_raw_output);
 584 }
 585
 586 static void diff_flush_patch(struct diff_file_pair *p)
 587 {
 588         const char *name, *other;
 589
 590         name = p->one->path;
 591         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
 592         if ((p->one->file_valid && S_ISDIR(p->one->mode)) ||
 593             (p->two->file_valid && S_ISDIR(p->two->mode)))
 594                 return; /* no tree diffs in patch format */
 595
 596         run_external_diff(name, other, p->one, p->two, p->xfrm_msg);
 597 }
 598
 599 static int identical(struct diff_filespec *one, struct diff_filespec *two)
 600 {
 601         /* This function is written stricter than necessary to support
 602          * the currently implemented transformers, but the idea is to
 603          * let transformers to produce diff_file_pairs any way they want,
 604          * and filter and clean them up here before producing the output.
 605          */
 606
 607         if (!one->file_valid && !two->file_valid)
 608                 return 1; /* not interesting */
 609
 610         /* deletion, addition, mode change and renames are all interesting. */
 611         if ((one->file_valid != two->file_valid) || (one->mode != two->mode) ||
 612             strcmp(one->path, two->path))
 613                 return 0;
 614
 615         /* both are valid and point at the same path.  that is, we are
 616          * dealing with a change.
 617          */
 618         if (one->sha1_valid && two->sha1_valid &&
 619             !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
 620                 return 1; /* no change */
 621         if (!one->sha1_valid && !two->sha1_valid)
 622                 return 1; /* both look at the same file on the filesystem. */
 623         return 0;
 624 }
 625
 626 static void diff_flush_one(struct diff_file_pair *p)
 627 {
 628         if (identical(p->one, p->two))
 629                 return;
 630         if (0 <= diff_raw_output)
 631                 diff_flush_raw(p);
 632         else
 633                 diff_flush_patch(p);
 634 }
 635
 636 void diff_flush(void)
 637 {
 638         struct diff_queue_struct *q = &queued_diff;
 639         int i;
 640
 641         if (detect_rename)
 642                 diff_detect_rename(q, detect_rename, minimum_score);
 643         for (i = 0; i < q->nr; i++)
 644                 diff_flush_one(q->queue[i]);
 645
 646         for (i = 0; i < q->nr; i++) {
 647                 struct diff_file_pair *p = q->queue[i];
 648                 diff_free_filespec_data(p->one);
 649                 diff_free_filespec_data(p->two);
 650                 free(p->xfrm_msg);
 651                 free(p);
 652         }
 653         free(q->queue);
 654         q->queue = NULL;
 655         q->nr = q->alloc = 0;
 656 }
 657
 658 void diff_addremove(int addremove, unsigned mode,
 659                     const unsigned char *sha1,
 660                     const char *base, const char *path)
 661 {
 662         char concatpath[PATH_MAX];
 663         struct diff_filespec *one, *two;
 664
 665         /* This may look odd, but it is a preparation for
 666          * feeding "there are unchanged files which should
 667          * not produce diffs, but when you are doing copy
 668          * detection you would need them, so here they are"
 669          * entries to the diff-core.  They will be prefixed
 670          * with something like '=' or '*' (I haven't decided
 671          * which but should not make any difference).
 672          * Feeding the same new and old to diff_change() should
 673          * also have the same effect.  diff_flush() should
 674          * filter the identical ones out at the final output
 675          * stage.
 676          */
 677         if (reverse_diff)
 678                 addremove = (addremove == '+' ? '-' :
 679                              addremove == '-' ? '+' : addremove);
 680
 681         if (!path) path = "";
 682         sprintf(concatpath, "%s%s", base, path);
 683         one = alloc_filespec(concatpath);
 684         two = alloc_filespec(concatpath);
 685
 686         if (addremove != '+')
 687                 fill_filespec(one, sha1, mode);
 688         if (addremove != '-')
 689                 fill_filespec(two, sha1, mode);
 690
 691         diff_queue(&queued_diff, one, two);
 692 }
 693
 694 void diff_change(unsigned old_mode, unsigned new_mode,
 695                  const unsigned char *old_sha1,
 696                  const unsigned char *new_sha1,
 697                  const char *base, const char *path) {
 698         char concatpath[PATH_MAX];
 699         struct diff_filespec *one, *two;
 700
 701         if (reverse_diff) {
 702                 unsigned tmp;
 703                 const unsigned char *tmp_c;
 704                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
 705                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
 706         }
 707         if (!path) path = "";
 708         sprintf(concatpath, "%s%s", base, path);
 709         one = alloc_filespec(concatpath);
 710         two = alloc_filespec(concatpath);
 711         fill_filespec(one, old_sha1, old_mode);
 712         fill_filespec(two, new_sha1, new_mode);
 713
 714         diff_queue(&queued_diff, one, two);
 715 }
 716
 717 void diff_unmerge(const char *path)
 718 {
 719         if (0 <= diff_raw_output) {
 720                 printf("U %s%c", path, diff_raw_output);
 721                 return;
 722         }
 723         run_external_diff(path, NULL, NULL, NULL, NULL);
 724 }