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 "diff.h"
   9 #include "diffcore.h"
  10
  11 static const char *diff_opts = "-pu";
  12 static unsigned char null_sha1[20] = { 0, };
  13
  14 static int reverse_diff;
  15 static int generate_patch;
  16 static int line_termination = '\n';
  17 static int inter_name_termination = '\t';
  18
  19 static const char *external_diff(void)
  20 {
  21         static const char *external_diff_cmd = NULL;
  22         static int done_preparing = 0;
  23
  24         if (done_preparing)
  25                 return external_diff_cmd;
  26
  27         /*
  28          * Default values above are meant to match the
  29          * Linux kernel development style.  Examples of
  30          * alternative styles you can specify via environment
  31          * variables are:
  32          *
  33          * GIT_DIFF_OPTS="-c";
  34          */
  35         if (gitenv("GIT_EXTERNAL_DIFF"))
  36                 external_diff_cmd = gitenv("GIT_EXTERNAL_DIFF");
  37
  38         /* In case external diff fails... */
  39         diff_opts = gitenv("GIT_DIFF_OPTS") ? : diff_opts;
  40
  41         done_preparing = 1;
  42         return external_diff_cmd;
  43 }
  44
  45 /* Help to copy the thing properly quoted for the shell safety.
  46  * any single quote is replaced with '\'', and the caller is
  47  * expected to enclose the result within a single quote pair.
  48  *
  49  * E.g.
  50  *  original     sq_expand     result
  51  *  name     ==> name      ==> 'name'
  52  *  a b      ==> a b       ==> 'a b'
  53  *  a'b      ==> a'\''b    ==> 'a'\''b'
  54  */
  55 static char *sq_expand(const char *src)
  56 {
  57         static char *buf = NULL;
  58         int cnt, c;
  59         const char *cp;
  60         char *bp;
  61
  62         /* count bytes needed to store the quoted string. */
  63         for (cnt = 1, cp = src; *cp; cnt++, cp++)
  64                 if (*cp == '\'')
  65                         cnt += 3;
  66
  67         buf = xmalloc(cnt);
  68         bp = buf;
  69         while ((c = *src++)) {
  70                 if (c != '\'')
  71                         *bp++ = c;
  72                 else {
  73                         bp = strcpy(bp, "'\\''");
  74                         bp += 4;
  75                 }
  76         }
  77         *bp = 0;
  78         return buf;
  79 }
  80
  81 static struct diff_tempfile {
  82         const char *name; /* filename external diff should read from */
  83         char hex[41];
  84         char mode[10];
  85         char tmp_path[50];
  86 } diff_temp[2];
  87
  88 static void builtin_diff(const char *name_a,
  89                          const char *name_b,
  90                          struct diff_tempfile *temp,
  91                          const char *xfrm_msg)
  92 {
  93         int i, next_at, cmd_size;
  94         const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
  95         const char *diff_arg  = "'%s' '%s'||:"; /* "||:" is to return 0 */
  96         const char *input_name_sq[2];
  97         const char *path0[2];
  98         const char *path1[2];
  99         const char *name_sq[2];
 100         char *cmd;
 101
 102         name_sq[0] = sq_expand(name_a);
 103         name_sq[1] = sq_expand(name_b);
 104
 105         /* diff_cmd and diff_arg have 6 %s in total which makes
 106          * the sum of these strings 12 bytes larger than required.
 107          * we use 2 spaces around diff-opts, and we need to count
 108          * terminating NUL, so we subtract 9 here.
 109          */
 110         cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
 111                         strlen(diff_arg) - 9);
 112         for (i = 0; i < 2; i++) {
 113                 input_name_sq[i] = sq_expand(temp[i].name);
 114                 if (!strcmp(temp[i].name, "/dev/null")) {
 115                         path0[i] = "/dev/null";
 116                         path1[i] = "";
 117                 } else {
 118                         path0[i] = i ? "b/" : "a/";
 119                         path1[i] = name_sq[i];
 120                 }
 121                 cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
 122                              strlen(input_name_sq[i]));
 123         }
 124
 125         cmd = xmalloc(cmd_size);
 126
 127         next_at = 0;
 128         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 129                             diff_cmd,
 130                             path0[0], path1[0], path0[1], path1[1]);
 131         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 132                             " %s ", diff_opts);
 133         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 134                             diff_arg, input_name_sq[0], input_name_sq[1]);
 135
 136         printf("diff --git a/%s b/%s\n", name_a, name_b);
 137         if (!path1[0][0])
 138                 printf("new file mode %s\n", temp[1].mode);
 139         else if (!path1[1][0])
 140                 printf("deleted file mode %s\n", temp[0].mode);
 141         else {
 142                 if (strcmp(temp[0].mode, temp[1].mode)) {
 143                         printf("old mode %s\n", temp[0].mode);
 144                         printf("new mode %s\n", temp[1].mode);
 145                 }
 146                 if (xfrm_msg && xfrm_msg[0])
 147                         fputs(xfrm_msg, stdout);
 148
 149                 if (strncmp(temp[0].mode, temp[1].mode, 3))
 150                         /* we do not run diff between different kind
 151                          * of objects.
 152                          */
 153                         exit(0);
 154         }
 155         fflush(NULL);
 156         execlp("/bin/sh","sh", "-c", cmd, NULL);
 157 }
 158
 159 struct diff_filespec *alloc_filespec(const char *path)
 160 {
 161         int namelen = strlen(path);
 162         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
 163         spec->path = (char *)(spec + 1);
 164         strcpy(spec->path, path);
 165         spec->should_free = spec->should_munmap = 0;
 166         spec->xfrm_flags = 0;
 167         spec->size = 0;
 168         spec->data = NULL;
 169         spec->mode = 0;
 170         memset(spec->sha1, 0, 20);
 171         return spec;
 172 }
 173
 174 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 175                    unsigned short mode)
 176 {
 177         if (mode) { /* just playing defensive */
 178                 spec->mode = mode;
 179                 memcpy(spec->sha1, sha1, 20);
 180                 spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
 181         }
 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 (!DIFF_FILE_VALID(s))
 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 = NULL;
 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 (!DIFF_FILE_VALID(one)) {
 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 /* An external diff command takes:
 391  *
 392  * diff-cmd name infile1 infile1-sha1 infile1-mode \
 393  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
 394  *
 395  */
 396 static void run_external_diff(const char *name,
 397                               const char *other,
 398                               struct diff_filespec *one,
 399                               struct diff_filespec *two,
 400                               const char *xfrm_msg)
 401 {
 402         struct diff_tempfile *temp = diff_temp;
 403         pid_t pid;
 404         int status;
 405         static int atexit_asked = 0;
 406
 407         if (one && two) {
 408                 prepare_temp_file(name, &temp[0], one);
 409                 prepare_temp_file(other ? : name, &temp[1], two);
 410                 if (! atexit_asked &&
 411                     (temp[0].name == temp[0].tmp_path ||
 412                      temp[1].name == temp[1].tmp_path)) {
 413                         atexit_asked = 1;
 414                         atexit(remove_tempfile);
 415                 }
 416                 signal(SIGINT, remove_tempfile_on_signal);
 417         }
 418
 419         fflush(NULL);
 420         pid = fork();
 421         if (pid < 0)
 422                 die("unable to fork");
 423         if (!pid) {
 424                 const char *pgm = external_diff();
 425                 if (pgm) {
 426                         if (one && two) {
 427                                 const char *exec_arg[10];
 428                                 const char **arg = &exec_arg[0];
 429                                 *arg++ = pgm;
 430                                 *arg++ = name;
 431                                 *arg++ = temp[0].name;
 432                                 *arg++ = temp[0].hex;
 433                                 *arg++ = temp[0].mode;
 434                                 *arg++ = temp[1].name;
 435                                 *arg++ = temp[1].hex;
 436                                 *arg++ = temp[1].mode;
 437                                 if (other) {
 438                                         *arg++ = other;
 439                                         *arg++ = xfrm_msg;
 440                                 }
 441                                 *arg = NULL;
 442                                 execvp(pgm, (char *const*) exec_arg);
 443                         }
 444                         else
 445                                 execlp(pgm, pgm, name, NULL);
 446                 }
 447                 /*
 448                  * otherwise we use the built-in one.
 449                  */
 450                 if (one && two)
 451                         builtin_diff(name, other ? : name, temp, xfrm_msg);
 452                 else
 453                         printf("* Unmerged path %s\n", name);
 454                 exit(0);
 455         }
 456         if (waitpid(pid, &status, 0) < 0 ||
 457             !WIFEXITED(status) || WEXITSTATUS(status)) {
 458                 /* Earlier we did not check the exit status because
 459                  * diff exits non-zero if files are different, and
 460                  * we are not interested in knowing that.  It was a
 461                  * mistake which made it harder to quit a diff-*
 462                  * session that uses the git-apply-patch-script as
 463                  * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
 464                  * should also exit non-zero only when it wants to
 465                  * abort the entire diff-* session.
 466                  */
 467                 remove_tempfile();
 468                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
 469                 exit(1);
 470         }
 471         remove_tempfile();
 472 }
 473
 474 void diff_setup(int reverse_diff_)
 475 {
 476         reverse_diff = reverse_diff_;
 477 }
 478
 479 struct diff_queue_struct diff_queued_diff;
 480
 481 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
 482 {
 483         if (queue->alloc <= queue->nr) {
 484                 queue->alloc = alloc_nr(queue->alloc);
 485                 queue->queue = xrealloc(queue->queue,
 486                                         sizeof(dp) * queue->alloc);
 487         }
 488         queue->queue[queue->nr++] = dp;
 489 }
 490
 491 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
 492                                  struct diff_filespec *one,
 493                                  struct diff_filespec *two)
 494 {
 495         struct diff_filepair *dp = xmalloc(sizeof(*dp));
 496         dp->one = one;
 497         dp->two = two;
 498         dp->score = 0;
 499         dp->orig_order = queue->nr;
 500         dp->rename_rank = 0;
 501         diff_q(queue, dp);
 502         return dp;
 503 }
 504
 505 static void diff_flush_raw(struct diff_filepair *p)
 506 {
 507         int two_paths;
 508         char status[10];
 509         switch (p->status) {
 510         case 'C': case 'R':
 511                 two_paths = 1;
 512                 sprintf(status, "%c%1d", p->status, p->score);
 513                 break;
 514         default:
 515                 two_paths = 0;
 516                 status[0] = p->status;
 517                 status[1] = 0;
 518                 break;
 519         }
 520         printf(":%06o %06o %s ",
 521                p->one->mode, p->two->mode, sha1_to_hex(p->one->sha1));
 522         printf("%s %s%c%s",
 523                sha1_to_hex(p->two->sha1),
 524                status,
 525                inter_name_termination,
 526                p->one->path);
 527         if (two_paths)
 528                 printf("%c%s", inter_name_termination, p->two->path);
 529         putchar(line_termination);
 530 }
 531
 532 int diff_unmodified_pair(struct diff_filepair *p)
 533 {
 534         /* This function is written stricter than necessary to support
 535          * the currently implemented transformers, but the idea is to
 536          * let transformers to produce diff_filepairs any way they want,
 537          * and filter and clean them up here before producing the output.
 538          */
 539         struct diff_filespec *one, *two;
 540
 541         if (DIFF_PAIR_UNMERGED(p))
 542                 return 0; /* unmerged is interesting */
 543
 544         one = p->one;
 545         two = p->two;
 546
 547         /* deletion, addition, mode change and renames are all interesting. */
 548         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
 549             (one->mode != two->mode) ||
 550             strcmp(one->path, two->path))
 551                 return 0;
 552
 553         /* both are valid and point at the same path.  that is, we are
 554          * dealing with a change.
 555          */
 556         if (one->sha1_valid && two->sha1_valid &&
 557             !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
 558                 return 1; /* no change */
 559         if (!one->sha1_valid && !two->sha1_valid)
 560                 return 1; /* both look at the same file on the filesystem. */
 561         return 0;
 562 }
 563
 564 static void diff_flush_patch(struct diff_filepair *p)
 565 {
 566         const char *name, *other;
 567         char msg_[PATH_MAX*2+200], *msg;
 568
 569         /* diffcore_prune() keeps "stay" entries for diff-raw
 570          * copy/rename detection, but when we are generating
 571          * patches we do not need them.
 572          */
 573         if (diff_unmodified_pair(p))
 574                 return;
 575
 576         name = p->one->path;
 577         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
 578         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
 579             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
 580                 return; /* no tree diffs in patch format */
 581
 582         switch (p->status) {
 583         case 'C':
 584                 sprintf(msg_,
 585                         "similarity index %d%%\n"
 586                         "copy from %s\n"
 587                         "copy to %s\n",
 588                         (int)(0.5 + p->score * 100/MAX_SCORE),
 589                         p->one->path, p->two->path);
 590                 msg = msg_;
 591                 break;
 592         case 'R':
 593                 sprintf(msg_,
 594                         "similarity index %d%%\n"
 595                         "rename old %s\n"
 596                         "rename new %s\n",
 597                         (int)(0.5 + p->score * 100/MAX_SCORE),
 598                         p->one->path, p->two->path);
 599                 msg = msg_;
 600                 break;
 601         default:
 602                 msg = NULL;
 603         }
 604
 605         if (DIFF_PAIR_UNMERGED(p))
 606                 run_external_diff(name, NULL, NULL, NULL, NULL);
 607         else
 608                 run_external_diff(name, other, p->one, p->two, msg);
 609 }
 610
 611 int diff_needs_to_stay(struct diff_queue_struct *q, int i,
 612                        struct diff_filespec *it)
 613 {
 614         /* If it will be used in later entry (either stay or used
 615          * as the source of rename/copy), we need to copy, not rename.
 616          */
 617         while (i < q->nr) {
 618                 struct diff_filepair *p = q->queue[i++];
 619                 if (!DIFF_FILE_VALID(p->two))
 620                         continue; /* removed is fine */
 621                 if (strcmp(p->one->path, it->path))
 622                         continue; /* not relevant */
 623
 624                 /* p has its src set to *it and it is not a delete;
 625                  * it will be used for in-place change, rename/copy,
 626                  * or just stays there.  We cannot rename it out.
 627                  */
 628                 return 1;
 629         }
 630         return 0;
 631 }
 632
 633 static int diff_used_as_source(struct diff_queue_struct *q, int lim,
 634                                struct diff_filespec *it)
 635 {
 636         int i;
 637         for (i = 0; i < lim; i++) {
 638                 struct diff_filepair *p = q->queue[i++];
 639                 if (!strcmp(p->one->path, it->path))
 640                         return 1;
 641         }
 642         return 0;
 643 }
 644
 645 void diffcore_prune(void)
 646 {
 647         /*
 648          * Although rename/copy detection wants to have "no-change"
 649          * entries fed into them, the downstream do not need to see
 650          * them, unless we had rename/copy for the same path earlier.
 651          * This function removes such entries.
 652          *
 653          * The applications that use rename/copy should:
 654          *
 655          * (1) feed change and "no-change" entries via diff_queue().
 656          * (2) call diffcore_rename, and any other future diffcore_xxx
 657          *     that would benefit by still having "no-change" entries.
 658          * (3) call diffcore_prune
 659          * (4) call other diffcore_xxx that do not need to see
 660          *     "no-change" entries.
 661          * (5) call diff_flush().
 662          */
 663         struct diff_queue_struct *q = &diff_queued_diff;
 664         struct diff_queue_struct outq;
 665         int i;
 666
 667         outq.queue = NULL;
 668         outq.nr = outq.alloc = 0;
 669
 670         for (i = 0; i < q->nr; i++) {
 671                 struct diff_filepair *p = q->queue[i];
 672                 if (!diff_unmodified_pair(p) ||
 673                     diff_used_as_source(q, i, p->one))
 674                         diff_q(&outq, p);
 675                 else
 676                         free(p);
 677         }
 678         free(q->queue);
 679         *q = outq;
 680         return;
 681 }
 682
 683 int diff_queue_is_empty(void)
 684 {
 685         struct diff_queue_struct *q = &diff_queued_diff;
 686         return q->nr == 0;
 687 }
 688
 689 void diff_flush(int diff_output_style, int resolve_rename_copy)
 690 {
 691         struct diff_queue_struct *q = &diff_queued_diff;
 692         int i;
 693
 694         generate_patch = 0;
 695         switch (diff_output_style) {
 696         case DIFF_FORMAT_HUMAN:
 697                 line_termination = '\n';
 698                 inter_name_termination = '\t';
 699                 break;
 700         case DIFF_FORMAT_MACHINE:
 701                 line_termination = inter_name_termination = 0;
 702                 break;
 703         case DIFF_FORMAT_PATCH:
 704                 generate_patch = 1;
 705                 break;
 706         }
 707         for (i = 0; i < q->nr; i++) {
 708                 struct diff_filepair *p = q->queue[i];
 709                 if (resolve_rename_copy) {
 710                         if (DIFF_PAIR_UNMERGED(p))
 711                                 p->status = 'U';
 712                         else if (!DIFF_FILE_VALID((p)->one))
 713                                 p->status = 'N';
 714                         else if (!DIFF_FILE_VALID((p)->two))
 715                                 p->status = 'D';
 716                         else if (strcmp(p->one->path, p->two->path)) {
 717                                 /* This is rename or copy.  Which one is it? */
 718                                 if (diff_needs_to_stay(q, i+1, p->one))
 719                                         p->status = 'C';
 720                                 else
 721                                         p->status = 'R';
 722                         }
 723                         else
 724                                 p->status = 'M';
 725                 }
 726                 if (generate_patch)
 727                         diff_flush_patch(p);
 728                 else
 729                         diff_flush_raw(p);
 730         }
 731
 732         for (i = 0; i < q->nr; i++) {
 733                 struct diff_filepair *p = q->queue[i];
 734                 diff_free_filespec_data(p->one);
 735                 diff_free_filespec_data(p->two);
 736                 free(p);
 737         }
 738         free(q->queue);
 739         q->queue = NULL;
 740         q->nr = q->alloc = 0;
 741 }
 742
 743 void diff_addremove(int addremove, unsigned mode,
 744                     const unsigned char *sha1,
 745                     const char *base, const char *path)
 746 {
 747         char concatpath[PATH_MAX];
 748         struct diff_filespec *one, *two;
 749
 750         /* This may look odd, but it is a preparation for
 751          * feeding "there are unchanged files which should
 752          * not produce diffs, but when you are doing copy
 753          * detection you would need them, so here they are"
 754          * entries to the diff-core.  They will be prefixed
 755          * with something like '=' or '*' (I haven't decided
 756          * which but should not make any difference).
 757          * Feeding the same new and old to diff_change()
 758          * also has the same effect.  diffcore_prune() should
 759          * be used to filter uninteresting ones out before the
 760          * final output happens.
 761          */
 762         if (reverse_diff)
 763                 addremove = (addremove == '+' ? '-' :
 764                              addremove == '-' ? '+' : addremove);
 765
 766         if (!path) path = "";
 767         sprintf(concatpath, "%s%s", base, path);
 768         one = alloc_filespec(concatpath);
 769         two = alloc_filespec(concatpath);
 770
 771         if (addremove != '+')
 772                 fill_filespec(one, sha1, mode);
 773         if (addremove != '-')
 774                 fill_filespec(two, sha1, mode);
 775
 776         diff_queue(&diff_queued_diff, one, two);
 777 }
 778
 779 void diff_helper_input(unsigned old_mode,
 780                        unsigned new_mode,
 781                        const unsigned char *old_sha1,
 782                        const unsigned char *new_sha1,
 783                        const char *old_path,
 784                        int status,
 785                        int score,
 786                        const char *new_path)
 787 {
 788         struct diff_filespec *one, *two;
 789         struct diff_filepair *dp;
 790
 791         one = alloc_filespec(old_path);
 792         two = alloc_filespec(new_path);
 793         if (old_mode)
 794                 fill_filespec(one, old_sha1, old_mode);
 795         if (new_mode)
 796                 fill_filespec(two, new_sha1, new_mode);
 797         dp = diff_queue(&diff_queued_diff, one, two);
 798         dp->score = score;
 799         dp->status = status;
 800 }
 801
 802 void diff_change(unsigned old_mode, unsigned new_mode,
 803                  const unsigned char *old_sha1,
 804                  const unsigned char *new_sha1,
 805                  const char *base, const char *path)
 806 {
 807         char concatpath[PATH_MAX];
 808         struct diff_filespec *one, *two;
 809
 810         if (reverse_diff) {
 811                 unsigned tmp;
 812                 const unsigned char *tmp_c;
 813                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
 814                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
 815         }
 816         if (!path) path = "";
 817         sprintf(concatpath, "%s%s", base, path);
 818         one = alloc_filespec(concatpath);
 819         two = alloc_filespec(concatpath);
 820         fill_filespec(one, old_sha1, old_mode);
 821         fill_filespec(two, new_sha1, new_mode);
 822
 823         diff_queue(&diff_queued_diff, one, two);
 824 }
 825
 826 void diff_unmerge(const char *path)
 827 {
 828         struct diff_filespec *one, *two;
 829         one = alloc_filespec(path);
 830         two = alloc_filespec(path);
 831         diff_queue(&diff_queued_diff, one, two);
 832 }