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 reverse_diff;
  16 static int diff_raw_output = -1;
  17 static const char **pathspec;
  18 static int speccnt;
  19
  20 static const char *external_diff(void)
  21 {
  22         static const char *external_diff_cmd = NULL;
  23         static int done_preparing = 0;
  24
  25         if (done_preparing)
  26                 return external_diff_cmd;
  27
  28         /*
  29          * Default values above are meant to match the
  30          * Linux kernel development style.  Examples of
  31          * alternative styles you can specify via environment
  32          * variables are:
  33          *
  34          * GIT_DIFF_OPTS="-c";
  35          */
  36         if (gitenv("GIT_EXTERNAL_DIFF"))
  37                 external_diff_cmd = gitenv("GIT_EXTERNAL_DIFF");
  38
  39         /* In case external diff fails... */
  40         diff_opts = gitenv("GIT_DIFF_OPTS") ? : diff_opts;
  41
  42         done_preparing = 1;
  43         return external_diff_cmd;
  44 }
  45
  46 /* Help to copy the thing properly quoted for the shell safety.
  47  * any single quote is replaced with '\'', and the caller is
  48  * expected to enclose the result within a single quote pair.
  49  *
  50  * E.g.
  51  *  original     sq_expand     result
  52  *  name     ==> name      ==> 'name'
  53  *  a b      ==> a b       ==> 'a b'
  54  *  a'b      ==> a'\''b    ==> 'a'\''b'
  55  */
  56 static char *sq_expand(const char *src)
  57 {
  58         static char *buf = NULL;
  59         int cnt, c;
  60         const char *cp;
  61         char *bp;
  62
  63         /* count bytes needed to store the quoted string. */
  64         for (cnt = 1, cp = src; *cp; cnt++, cp++)
  65                 if (*cp == '\'')
  66                         cnt += 3;
  67
  68         buf = xmalloc(cnt);
  69         bp = buf;
  70         while ((c = *src++)) {
  71                 if (c != '\'')
  72                         *bp++ = c;
  73                 else {
  74                         bp = strcpy(bp, "'\\''");
  75                         bp += 4;
  76                 }
  77         }
  78         *bp = 0;
  79         return buf;
  80 }
  81
  82 static struct diff_tempfile {
  83         const char *name; /* filename external diff should read from */
  84         char hex[41];
  85         char mode[10];
  86         char tmp_path[50];
  87 } diff_temp[2];
  88
  89 static void builtin_diff(const char *name_a,
  90                          const char *name_b,
  91                          struct diff_tempfile *temp,
  92                          const char *xfrm_msg)
  93 {
  94         int i, next_at, cmd_size;
  95         const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
  96         const char *diff_arg  = "'%s' '%s'||:"; /* "||:" is to return 0 */
  97         const char *input_name_sq[2];
  98         const char *path0[2];
  99         const char *path1[2];
 100         const char *name_sq[2];
 101         char *cmd;
 102
 103         name_sq[0] = sq_expand(name_a);
 104         name_sq[1] = sq_expand(name_b);
 105
 106         /* diff_cmd and diff_arg have 6 %s in total which makes
 107          * the sum of these strings 12 bytes larger than required.
 108          * we use 2 spaces around diff-opts, and we need to count
 109          * terminating NUL, so we subtract 9 here.
 110          */
 111         cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
 112                         strlen(diff_arg) - 9);
 113         for (i = 0; i < 2; i++) {
 114                 input_name_sq[i] = sq_expand(temp[i].name);
 115                 if (!strcmp(temp[i].name, "/dev/null")) {
 116                         path0[i] = "/dev/null";
 117                         path1[i] = "";
 118                 } else {
 119                         path0[i] = i ? "b/" : "a/";
 120                         path1[i] = name_sq[i];
 121                 }
 122                 cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
 123                              strlen(input_name_sq[i]));
 124         }
 125
 126         cmd = xmalloc(cmd_size);
 127
 128         next_at = 0;
 129         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 130                             diff_cmd,
 131                             path0[0], path1[0], path0[1], path1[1]);
 132         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 133                             " %s ", diff_opts);
 134         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 135                             diff_arg, input_name_sq[0], input_name_sq[1]);
 136
 137         printf("diff --git a/%s b/%s\n", name_a, name_b);
 138         if (!path1[0][0])
 139                 printf("new file mode %s\n", temp[1].mode);
 140         else if (!path1[1][0])
 141                 printf("deleted file mode %s\n", temp[0].mode);
 142         else {
 143                 if (strcmp(temp[0].mode, temp[1].mode)) {
 144                         printf("old mode %s\n", temp[0].mode);
 145                         printf("new mode %s\n", temp[1].mode);
 146                 }
 147                 if (xfrm_msg && xfrm_msg[0])
 148                         fputs(xfrm_msg, stdout);
 149
 150                 if (strncmp(temp[0].mode, temp[1].mode, 3))
 151                         /* we do not run diff between different kind
 152                          * of objects.
 153                          */
 154                         exit(0);
 155         }
 156         fflush(NULL);
 157         execlp("/bin/sh","sh", "-c", cmd, NULL);
 158 }
 159
 160 struct diff_filespec *alloc_filespec(const char *path)
 161 {
 162         int namelen = strlen(path);
 163         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
 164         spec->path = (char *)(spec + 1);
 165         strcpy(spec->path, path);
 166         spec->should_free = spec->should_munmap = spec->file_valid = 0;
 167         spec->xfrm_flags = 0;
 168         spec->size = 0;
 169         spec->data = 0;
 170         return spec;
 171 }
 172
 173 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 174                    unsigned short mode)
 175 {
 176         spec->mode = mode;
 177         memcpy(spec->sha1, sha1, 20);
 178         spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
 179         spec->file_valid = 1;
 180 }
 181
 182 /*
 183  * Given a name and sha1 pair, if the dircache tells us the file in
 184  * the work tree has that object contents, return true, so that
 185  * prepare_temp_file() does not have to inflate and extract.
 186  */
 187 static int work_tree_matches(const char *name, const unsigned char *sha1)
 188 {
 189         struct cache_entry *ce;
 190         struct stat st;
 191         int pos, len;
 192
 193         /* We do not read the cache ourselves here, because the
 194          * benchmark with my previous version that always reads cache
 195          * shows that it makes things worse for diff-tree comparing
 196          * two linux-2.6 kernel trees in an already checked out work
 197          * tree.  This is because most diff-tree comparisons deal with
 198          * only a small number of files, while reading the cache is
 199          * expensive for a large project, and its cost outweighs the
 200          * savings we get by not inflating the object to a temporary
 201          * file.  Practically, this code only helps when we are used
 202          * by diff-cache --cached, which does read the cache before
 203          * calling us.
 204          */
 205         if (!active_cache)
 206                 return 0;
 207
 208         len = strlen(name);
 209         pos = cache_name_pos(name, len);
 210         if (pos < 0)
 211                 return 0;
 212         ce = active_cache[pos];
 213         if ((lstat(name, &st) < 0) ||
 214             !S_ISREG(st.st_mode) || /* careful! */
 215             ce_match_stat(ce, &st) ||
 216             memcmp(sha1, ce->sha1, 20))
 217                 return 0;
 218         /* we return 1 only when we can stat, it is a regular file,
 219          * stat information matches, and sha1 recorded in the cache
 220          * matches.  I.e. we know the file in the work tree really is
 221          * the same as the <name, sha1> pair.
 222          */
 223         return 1;
 224 }
 225
 226 /*
 227  * While doing rename detection and pickaxe operation, we may need to
 228  * grab the data for the blob (or file) for our own in-core comparison.
 229  * diff_filespec has data and size fields for this purpose.
 230  */
 231 int diff_populate_filespec(struct diff_filespec *s)
 232 {
 233         int err = 0;
 234         if (!s->file_valid)
 235                 die("internal error: asking to populate invalid file.");
 236         if (S_ISDIR(s->mode))
 237                 return -1;
 238
 239         if (s->data)
 240                 return err;
 241         if (!s->sha1_valid ||
 242             work_tree_matches(s->path, s->sha1)) {
 243                 struct stat st;
 244                 int fd;
 245                 if (lstat(s->path, &st) < 0) {
 246                         if (errno == ENOENT) {
 247                         err_empty:
 248                                 err = -1;
 249                         empty:
 250                                 s->data = "";
 251                                 s->size = 0;
 252                                 return err;
 253                         }
 254                 }
 255                 s->size = st.st_size;
 256                 if (!s->size)
 257                         goto empty;
 258                 if (S_ISLNK(st.st_mode)) {
 259                         int ret;
 260                         s->data = xmalloc(s->size);
 261                         s->should_free = 1;
 262                         ret = readlink(s->path, s->data, s->size);
 263                         if (ret < 0) {
 264                                 free(s->data);
 265                                 goto err_empty;
 266                         }
 267                         return 0;
 268                 }
 269                 fd = open(s->path, O_RDONLY);
 270                 if (fd < 0)
 271                         goto err_empty;
 272                 s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
 273                 s->should_munmap = 1;
 274                 close(fd);
 275         }
 276         else {
 277                 char type[20];
 278                 s->data = read_sha1_file(s->sha1, type, &s->size);
 279                 s->should_free = 1;
 280         }
 281         return 0;
 282 }
 283
 284 void diff_free_filespec_data(struct diff_filespec *s)
 285 {
 286         if (s->should_free)
 287                 free(s->data);
 288         else if (s->should_munmap)
 289                 munmap(s->data, s->size);
 290         s->should_free = s->should_munmap = 0;
 291         s->data = 0;
 292 }
 293
 294 static void prep_temp_blob(struct diff_tempfile *temp,
 295                            void *blob,
 296                            unsigned long size,
 297                            unsigned char *sha1,
 298                            int mode)
 299 {
 300         int fd;
 301
 302         strcpy(temp->tmp_path, ".diff_XXXXXX");
 303         fd = mkstemp(temp->tmp_path);
 304         if (fd < 0)
 305                 die("unable to create temp-file");
 306         if (write(fd, blob, size) != size)
 307                 die("unable to write temp-file");
 308         close(fd);
 309         temp->name = temp->tmp_path;
 310         strcpy(temp->hex, sha1_to_hex(sha1));
 311         temp->hex[40] = 0;
 312         sprintf(temp->mode, "%06o", mode);
 313 }
 314
 315 static void prepare_temp_file(const char *name,
 316                               struct diff_tempfile *temp,
 317                               struct diff_filespec *one)
 318 {
 319         if (!one->file_valid) {
 320         not_a_valid_file:
 321                 /* A '-' entry produces this for file-2, and
 322                  * a '+' entry produces this for file-1.
 323                  */
 324                 temp->name = "/dev/null";
 325                 strcpy(temp->hex, ".");
 326                 strcpy(temp->mode, ".");
 327                 return;
 328         }
 329
 330         if (!one->sha1_valid ||
 331             work_tree_matches(name, one->sha1)) {
 332                 struct stat st;
 333                 if (lstat(name, &st) < 0) {
 334                         if (errno == ENOENT)
 335                                 goto not_a_valid_file;
 336                         die("stat(%s): %s", name, strerror(errno));
 337                 }
 338                 if (S_ISLNK(st.st_mode)) {
 339                         int ret;
 340                         char *buf, buf_[1024];
 341                         buf = ((sizeof(buf_) < st.st_size) ?
 342                                xmalloc(st.st_size) : buf_);
 343                         ret = readlink(name, buf, st.st_size);
 344                         if (ret < 0)
 345                                 die("readlink(%s)", name);
 346                         prep_temp_blob(temp, buf, st.st_size,
 347                                        (one->sha1_valid ?
 348                                         one->sha1 : null_sha1),
 349                                        (one->sha1_valid ?
 350                                         one->mode : S_IFLNK));
 351                 }
 352                 else {
 353                         /* we can borrow from the file in the work tree */
 354                         temp->name = name;
 355                         if (!one->sha1_valid)
 356                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
 357                         else
 358                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
 359                         sprintf(temp->mode, "%06o",
 360                                 S_IFREG |ce_permissions(st.st_mode));
 361                 }
 362                 return;
 363         }
 364         else {
 365                 if (diff_populate_filespec(one))
 366                         die("cannot read data blob for %s", one->path);
 367                 prep_temp_blob(temp, one->data, one->size,
 368                                one->sha1, one->mode);
 369         }
 370 }
 371
 372 static void remove_tempfile(void)
 373 {
 374         int i;
 375
 376         for (i = 0; i < 2; i++)
 377                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
 378                         unlink(diff_temp[i].name);
 379                         diff_temp[i].name = NULL;
 380                 }
 381 }
 382
 383 static void remove_tempfile_on_signal(int signo)
 384 {
 385         remove_tempfile();
 386 }
 387
 388 static int matches_pathspec(const char *name)
 389 {
 390         int i;
 391         int namelen;
 392
 393         if (speccnt == 0)
 394                 return 1;
 395
 396         namelen = strlen(name);
 397         for (i = 0; i < speccnt; i++) {
 398                 int speclen = strlen(pathspec[i]);
 399                 if (! strncmp(pathspec[i], name, speclen) &&
 400                     speclen <= namelen &&
 401                     (name[speclen] == 0 || name[speclen] == '/'))
 402                         return 1;
 403         }
 404         return 0;
 405 }
 406
 407 /* An external diff command takes:
 408  *
 409  * diff-cmd name infile1 infile1-sha1 infile1-mode \
 410  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
 411  *
 412  */
 413 static void run_external_diff(const char *name,
 414                               const char *other,
 415                               struct diff_filespec *one,
 416                               struct diff_filespec *two,
 417                               const char *xfrm_msg)
 418 {
 419         struct diff_tempfile *temp = diff_temp;
 420         pid_t pid;
 421         int status;
 422         static int atexit_asked = 0;
 423
 424         if (!matches_pathspec(name) && (!other || !matches_pathspec(other)))
 425                 return;
 426
 427         if (one && two) {
 428                 prepare_temp_file(name, &temp[0], one);
 429                 prepare_temp_file(other ? : name, &temp[1], two);
 430                 if (! atexit_asked &&
 431                     (temp[0].name == temp[0].tmp_path ||
 432                      temp[1].name == temp[1].tmp_path)) {
 433                         atexit_asked = 1;
 434                         atexit(remove_tempfile);
 435                 }
 436                 signal(SIGINT, remove_tempfile_on_signal);
 437         }
 438
 439         fflush(NULL);
 440         pid = fork();
 441         if (pid < 0)
 442                 die("unable to fork");
 443         if (!pid) {
 444                 const char *pgm = external_diff();
 445                 if (pgm) {
 446                         if (one && two) {
 447                                 const char *exec_arg[10];
 448                                 const char **arg = &exec_arg[0];
 449                                 *arg++ = pgm;
 450                                 *arg++ = name;
 451                                 *arg++ = temp[0].name;
 452                                 *arg++ = temp[0].hex;
 453                                 *arg++ = temp[0].mode;
 454                                 *arg++ = temp[1].name;
 455                                 *arg++ = temp[1].hex;
 456                                 *arg++ = temp[1].mode;
 457                                 if (other) {
 458                                         *arg++ = other;
 459                                         *arg++ = xfrm_msg;
 460                                 }
 461                                 *arg = 0;
 462                                 execvp(pgm, (char *const*) exec_arg);
 463                         }
 464                         else
 465                                 execlp(pgm, pgm, name, NULL);
 466                 }
 467                 /*
 468                  * otherwise we use the built-in one.
 469                  */
 470                 if (one && two)
 471                         builtin_diff(name, other ? : name, temp, xfrm_msg);
 472                 else
 473                         printf("* Unmerged path %s\n", name);
 474                 exit(0);
 475         }
 476         if (waitpid(pid, &status, 0) < 0 ||
 477             !WIFEXITED(status) || WEXITSTATUS(status)) {
 478                 /* Earlier we did not check the exit status because
 479                  * diff exits non-zero if files are different, and
 480                  * we are not interested in knowing that.  It was a
 481                  * mistake which made it harder to quit a diff-*
 482                  * session that uses the git-apply-patch-script as
 483                  * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
 484                  * should also exit non-zero only when it wants to
 485                  * abort the entire diff-* session.
 486                  */
 487                 remove_tempfile();
 488                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
 489                 exit(1);
 490         }
 491         remove_tempfile();
 492 }
 493
 494 int diff_scoreopt_parse(const char *opt)
 495 {
 496         int diglen, num, scale, i;
 497         if (opt[0] != '-' || (opt[1] != 'M' && opt[1] != 'C'))
 498                 return -1; /* that is not a -M nor -C option */
 499         diglen = strspn(opt+2, "0123456789");
 500         if (diglen == 0 || strlen(opt+2) != diglen)
 501                 return 0; /* use default */
 502         sscanf(opt+2, "%d", &num);
 503         for (i = 0, scale = 1; i < diglen; i++)
 504                 scale *= 10;
 505
 506         /* user says num divided by scale and we say internally that
 507          * is MAX_SCORE * num / scale.
 508          */
 509         return MAX_SCORE * num / scale;
 510 }
 511
 512 void diff_setup(int reverse_diff_, int diff_raw_output_)
 513 {
 514         reverse_diff = reverse_diff_;
 515         diff_raw_output = diff_raw_output_;
 516 }
 517
 518 struct diff_queue_struct diff_queued_diff;
 519
 520 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
 521                                   struct diff_filespec *one,
 522                                   struct diff_filespec *two)
 523 {
 524         struct diff_filepair *dp = xmalloc(sizeof(*dp));
 525         dp->one = one;
 526         dp->two = two;
 527         dp->xfrm_msg = 0;
 528         dp->orig_order = queue->nr;
 529         dp->xfrm_work = 0;
 530         if (queue->alloc <= queue->nr) {
 531                 queue->alloc = alloc_nr(queue->alloc);
 532                 queue->queue = xrealloc(queue->queue,
 533                                        sizeof(dp) * queue->alloc);
 534         }
 535         queue->queue[queue->nr++] = dp;
 536         return dp;
 537 }
 538
 539 static const char *git_object_type(unsigned mode)
 540 {
 541         return S_ISDIR(mode) ? "tree" : "blob";
 542 }
 543
 544 static void diff_flush_raw(struct diff_filepair *p)
 545 {
 546         struct diff_filespec *it;
 547         int addremove;
 548
 549         /* raw output does not have a way to express rename nor copy */
 550         if (strcmp(p->one->path, p->two->path))
 551                 return;
 552
 553         if (p->one->file_valid && p->two->file_valid) {
 554                 char hex[41];
 555                 strcpy(hex, sha1_to_hex(p->one->sha1));
 556                 printf("*%06o->%06o %s %s->%s %s%c",
 557                        p->one->mode, p->two->mode,
 558                        git_object_type(p->one->mode),
 559                        hex, sha1_to_hex(p->two->sha1),
 560                        p->one->path, diff_raw_output);
 561                 return;
 562         }
 563
 564         if (p->one->file_valid) {
 565                 it = p->one;
 566                 addremove = '-';
 567         } else {
 568                 it = p->two;
 569                 addremove = '+';
 570         }
 571
 572         printf("%c%06o %s %s %s%c",
 573                addremove,
 574                it->mode, git_object_type(it->mode),
 575                sha1_to_hex(it->sha1), it->path, diff_raw_output);
 576 }
 577
 578 static void diff_flush_patch(struct diff_filepair *p)
 579 {
 580         const char *name, *other;
 581
 582         name = p->one->path;
 583         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
 584         if ((p->one->file_valid && S_ISDIR(p->one->mode)) ||
 585             (p->two->file_valid && S_ISDIR(p->two->mode)))
 586                 return; /* no tree diffs in patch format */
 587
 588         run_external_diff(name, other, p->one, p->two, p->xfrm_msg);
 589 }
 590
 591 static int identical(struct diff_filespec *one, struct diff_filespec *two)
 592 {
 593         /* This function is written stricter than necessary to support
 594          * the currently implemented transformers, but the idea is to
 595          * let transformers to produce diff_filepairs any way they want,
 596          * and filter and clean them up here before producing the output.
 597          */
 598
 599         if (!one->file_valid && !two->file_valid)
 600                 return 1; /* not interesting */
 601
 602         /* deletion, addition, mode change and renames are all interesting. */
 603         if ((one->file_valid != two->file_valid) || (one->mode != two->mode) ||
 604             strcmp(one->path, two->path))
 605                 return 0;
 606
 607         /* both are valid and point at the same path.  that is, we are
 608          * dealing with a change.
 609          */
 610         if (one->sha1_valid && two->sha1_valid &&
 611             !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
 612                 return 1; /* no change */
 613         if (!one->sha1_valid && !two->sha1_valid)
 614                 return 1; /* both look at the same file on the filesystem. */
 615         return 0;
 616 }
 617
 618 static void diff_flush_one(struct diff_filepair *p)
 619 {
 620         if (identical(p->one, p->two))
 621                 return;
 622         if (0 <= diff_raw_output)
 623                 diff_flush_raw(p);
 624         else
 625                 diff_flush_patch(p);
 626 }
 627
 628 int diff_queue_is_empty(void)
 629 {
 630         struct diff_queue_struct *q = &diff_queued_diff;
 631         int i;
 632
 633         for (i = 0; i < q->nr; i++) {
 634                 struct diff_filepair *p = q->queue[i];
 635                 if (!identical(p->one, p->two))
 636                         return 0;
 637         }
 638         return 1;
 639 }
 640
 641 void diff_flush(const char **pathspec_, int speccnt_)
 642 {
 643         struct diff_queue_struct *q = &diff_queued_diff;
 644         int i;
 645
 646         pathspec = pathspec_;
 647         speccnt = speccnt_;
 648
 649         for (i = 0; i < q->nr; i++)
 650                 diff_flush_one(q->queue[i]);
 651
 652         for (i = 0; i < q->nr; i++) {
 653                 struct diff_filepair *p = q->queue[i];
 654                 diff_free_filespec_data(p->one);
 655                 diff_free_filespec_data(p->two);
 656                 free(p->xfrm_msg);
 657                 free(p);
 658         }
 659         free(q->queue);
 660         q->queue = NULL;
 661         q->nr = q->alloc = 0;
 662 }
 663
 664 void diff_addremove(int addremove, unsigned mode,
 665                     const unsigned char *sha1,
 666                     const char *base, const char *path)
 667 {
 668         char concatpath[PATH_MAX];
 669         struct diff_filespec *one, *two;
 670
 671         /* This may look odd, but it is a preparation for
 672          * feeding "there are unchanged files which should
 673          * not produce diffs, but when you are doing copy
 674          * detection you would need them, so here they are"
 675          * entries to the diff-core.  They will be prefixed
 676          * with something like '=' or '*' (I haven't decided
 677          * which but should not make any difference).
 678          * Feeding the same new and old to diff_change() should
 679          * also have the same effect.  diff_flush() should
 680          * filter the identical ones out at the final output
 681          * stage.
 682          */
 683         if (reverse_diff)
 684                 addremove = (addremove == '+' ? '-' :
 685                              addremove == '-' ? '+' : addremove);
 686
 687         if (!path) path = "";
 688         sprintf(concatpath, "%s%s", base, path);
 689         one = alloc_filespec(concatpath);
 690         two = alloc_filespec(concatpath);
 691
 692         if (addremove != '+')
 693                 fill_filespec(one, sha1, mode);
 694         if (addremove != '-')
 695                 fill_filespec(two, sha1, mode);
 696
 697         diff_queue(&diff_queued_diff, one, two);
 698 }
 699
 700 void diff_change(unsigned old_mode, unsigned new_mode,
 701                  const unsigned char *old_sha1,
 702                  const unsigned char *new_sha1,
 703                  const char *base, const char *path) {
 704         char concatpath[PATH_MAX];
 705         struct diff_filespec *one, *two;
 706
 707         if (reverse_diff) {
 708                 unsigned tmp;
 709                 const unsigned char *tmp_c;
 710                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
 711                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
 712         }
 713         if (!path) path = "";
 714         sprintf(concatpath, "%s%s", base, path);
 715         one = alloc_filespec(concatpath);
 716         two = alloc_filespec(concatpath);
 717         fill_filespec(one, old_sha1, old_mode);
 718         fill_filespec(two, new_sha1, new_mode);
 719
 720         diff_queue(&diff_queued_diff, one, two);
 721 }
 722
 723 void diff_unmerge(const char *path)
 724 {
 725         if (0 <= diff_raw_output) {
 726                 printf("U %s%c", path, diff_raw_output);
 727                 return;
 728         }
 729         run_external_diff(path, NULL, NULL, NULL, NULL);
 730 }