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
  16 static const char *external_diff(void)
  17 {
  18         static const char *external_diff_cmd = NULL;
  19         static int done_preparing = 0;
  20
  21         if (done_preparing)
  22                 return external_diff_cmd;
  23
  24         /*
  25          * Default values above are meant to match the
  26          * Linux kernel development style.  Examples of
  27          * alternative styles you can specify via environment
  28          * variables are:
  29          *
  30          * GIT_DIFF_OPTS="-c";
  31          */
  32         if (gitenv("GIT_EXTERNAL_DIFF"))
  33                 external_diff_cmd = gitenv("GIT_EXTERNAL_DIFF");
  34
  35         /* In case external diff fails... */
  36         diff_opts = gitenv("GIT_DIFF_OPTS") ? : diff_opts;
  37
  38         done_preparing = 1;
  39         return external_diff_cmd;
  40 }
  41
  42 /* Help to copy the thing properly quoted for the shell safety.
  43  * any single quote is replaced with '\'', and the caller is
  44  * expected to enclose the result within a single quote pair.
  45  *
  46  * E.g.
  47  *  original     sq_expand     result
  48  *  name     ==> name      ==> 'name'
  49  *  a b      ==> a b       ==> 'a b'
  50  *  a'b      ==> a'\''b    ==> 'a'\''b'
  51  */
  52 static char *sq_expand(const char *src)
  53 {
  54         static char *buf = NULL;
  55         int cnt, c;
  56         const char *cp;
  57         char *bp;
  58
  59         /* count bytes needed to store the quoted string. */
  60         for (cnt = 1, cp = src; *cp; cnt++, cp++)
  61                 if (*cp == '\'')
  62                         cnt += 3;
  63
  64         buf = xmalloc(cnt);
  65         bp = buf;
  66         while ((c = *src++)) {
  67                 if (c != '\'')
  68                         *bp++ = c;
  69                 else {
  70                         bp = strcpy(bp, "'\\''");
  71                         bp += 4;
  72                 }
  73         }
  74         *bp = 0;
  75         return buf;
  76 }
  77
  78 static struct diff_tempfile {
  79         const char *name; /* filename external diff should read from */
  80         char hex[41];
  81         char mode[10];
  82         char tmp_path[50];
  83 } diff_temp[2];
  84
  85 static void builtin_diff(const char *name_a,
  86                          const char *name_b,
  87                          struct diff_tempfile *temp,
  88                          const char *xfrm_msg)
  89 {
  90         int i, next_at, cmd_size;
  91         const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
  92         const char *diff_arg  = "'%s' '%s'||:"; /* "||:" is to return 0 */
  93         const char *input_name_sq[2];
  94         const char *path0[2];
  95         const char *path1[2];
  96         const char *name_sq[2];
  97         char *cmd;
  98
  99         name_sq[0] = sq_expand(name_a);
 100         name_sq[1] = sq_expand(name_b);
 101
 102         /* diff_cmd and diff_arg have 6 %s in total which makes
 103          * the sum of these strings 12 bytes larger than required.
 104          * we use 2 spaces around diff-opts, and we need to count
 105          * terminating NUL, so we subtract 9 here.
 106          */
 107         cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
 108                         strlen(diff_arg) - 9);
 109         for (i = 0; i < 2; i++) {
 110                 input_name_sq[i] = sq_expand(temp[i].name);
 111                 if (!strcmp(temp[i].name, "/dev/null")) {
 112                         path0[i] = "/dev/null";
 113                         path1[i] = "";
 114                 } else {
 115                         path0[i] = i ? "b/" : "a/";
 116                         path1[i] = name_sq[i];
 117                 }
 118                 cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
 119                              strlen(input_name_sq[i]));
 120         }
 121
 122         cmd = xmalloc(cmd_size);
 123
 124         next_at = 0;
 125         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 126                             diff_cmd,
 127                             path0[0], path1[0], path0[1], path1[1]);
 128         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 129                             " %s ", diff_opts);
 130         next_at += snprintf(cmd+next_at, cmd_size-next_at,
 131                             diff_arg, input_name_sq[0], input_name_sq[1]);
 132
 133         printf("diff --git a/%s b/%s\n", name_a, name_b);
 134         if (!path1[0][0])
 135                 printf("new file mode %s\n", temp[1].mode);
 136         else if (!path1[1][0])
 137                 printf("deleted file mode %s\n", temp[0].mode);
 138         else {
 139                 if (strcmp(temp[0].mode, temp[1].mode)) {
 140                         printf("old mode %s\n", temp[0].mode);
 141                         printf("new mode %s\n", temp[1].mode);
 142                 }
 143                 if (xfrm_msg && xfrm_msg[0])
 144                         puts(xfrm_msg);
 145
 146                 if (strncmp(temp[0].mode, temp[1].mode, 3))
 147                         /* we do not run diff between different kind
 148                          * of objects.
 149                          */
 150                         exit(0);
 151         }
 152         fflush(NULL);
 153         execlp("/bin/sh","sh", "-c", cmd, NULL);
 154 }
 155
 156 struct diff_filespec *alloc_filespec(const char *path)
 157 {
 158         int namelen = strlen(path);
 159         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
 160         spec->path = (char *)(spec + 1);
 161         strcpy(spec->path, path);
 162         spec->should_free = spec->should_munmap = 0;
 163         spec->xfrm_flags = 0;
 164         spec->size = 0;
 165         spec->data = NULL;
 166         spec->mode = 0;
 167         memset(spec->sha1, 0, 20);
 168         return spec;
 169 }
 170
 171 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 172                    unsigned short mode)
 173 {
 174         if (mode) {
 175                 spec->mode = DIFF_FILE_CANON_MODE(mode);
 176                 memcpy(spec->sha1, sha1, 20);
 177                 spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
 178         }
 179 }
 180
 181 /*
 182  * Given a name and sha1 pair, if the dircache tells us the file in
 183  * the work tree has that object contents, return true, so that
 184  * prepare_temp_file() does not have to inflate and extract.
 185  */
 186 static int work_tree_matches(const char *name, const unsigned char *sha1)
 187 {
 188         struct cache_entry *ce;
 189         struct stat st;
 190         int pos, len;
 191
 192         /* We do not read the cache ourselves here, because the
 193          * benchmark with my previous version that always reads cache
 194          * shows that it makes things worse for diff-tree comparing
 195          * two linux-2.6 kernel trees in an already checked out work
 196          * tree.  This is because most diff-tree comparisons deal with
 197          * only a small number of files, while reading the cache is
 198          * expensive for a large project, and its cost outweighs the
 199          * savings we get by not inflating the object to a temporary
 200          * file.  Practically, this code only helps when we are used
 201          * by diff-cache --cached, which does read the cache before
 202          * calling us.
 203          */
 204         if (!active_cache)
 205                 return 0;
 206
 207         len = strlen(name);
 208         pos = cache_name_pos(name, len);
 209         if (pos < 0)
 210                 return 0;
 211         ce = active_cache[pos];
 212         if ((lstat(name, &st) < 0) ||
 213             !S_ISREG(st.st_mode) || /* careful! */
 214             ce_match_stat(ce, &st) ||
 215             memcmp(sha1, ce->sha1, 20))
 216                 return 0;
 217         /* we return 1 only when we can stat, it is a regular file,
 218          * stat information matches, and sha1 recorded in the cache
 219          * matches.  I.e. we know the file in the work tree really is
 220          * the same as the <name, sha1> pair.
 221          */
 222         return 1;
 223 }
 224
 225 /*
 226  * While doing rename detection and pickaxe operation, we may need to
 227  * grab the data for the blob (or file) for our own in-core comparison.
 228  * diff_filespec has data and size fields for this purpose.
 229  */
 230 int diff_populate_filespec(struct diff_filespec *s)
 231 {
 232         int err = 0;
 233         if (!DIFF_FILE_VALID(s))
 234                 die("internal error: asking to populate invalid file.");
 235         if (S_ISDIR(s->mode))
 236                 return -1;
 237
 238         if (s->data)
 239                 return err;
 240         if (!s->sha1_valid ||
 241             work_tree_matches(s->path, s->sha1)) {
 242                 struct stat st;
 243                 int fd;
 244                 if (lstat(s->path, &st) < 0) {
 245                         if (errno == ENOENT) {
 246                         err_empty:
 247                                 err = -1;
 248                         empty:
 249                                 s->data = "";
 250                                 s->size = 0;
 251                                 return err;
 252                         }
 253                 }
 254                 s->size = st.st_size;
 255                 if (!s->size)
 256                         goto empty;
 257                 if (S_ISLNK(st.st_mode)) {
 258                         int ret;
 259                         s->data = xmalloc(s->size);
 260                         s->should_free = 1;
 261                         ret = readlink(s->path, s->data, s->size);
 262                         if (ret < 0) {
 263                                 free(s->data);
 264                                 goto err_empty;
 265                         }
 266                         return 0;
 267                 }
 268                 fd = open(s->path, O_RDONLY);
 269                 if (fd < 0)
 270                         goto err_empty;
 271                 s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
 272                 s->should_munmap = 1;
 273                 close(fd);
 274         }
 275         else {
 276                 char type[20];
 277                 s->data = read_sha1_file(s->sha1, type, &s->size);
 278                 s->should_free = 1;
 279         }
 280         return 0;
 281 }
 282
 283 void diff_free_filespec_data(struct diff_filespec *s)
 284 {
 285         if (s->should_free)
 286                 free(s->data);
 287         else if (s->should_munmap)
 288                 munmap(s->data, s->size);
 289         s->should_free = s->should_munmap = 0;
 290         s->data = NULL;
 291 }
 292
 293 static void prep_temp_blob(struct diff_tempfile *temp,
 294                            void *blob,
 295                            unsigned long size,
 296                            unsigned char *sha1,
 297                            int mode)
 298 {
 299         int fd;
 300
 301         strcpy(temp->tmp_path, ".diff_XXXXXX");
 302         fd = mkstemp(temp->tmp_path);
 303         if (fd < 0)
 304                 die("unable to create temp-file");
 305         if (write(fd, blob, size) != size)
 306                 die("unable to write temp-file");
 307         close(fd);
 308         temp->name = temp->tmp_path;
 309         strcpy(temp->hex, sha1_to_hex(sha1));
 310         temp->hex[40] = 0;
 311         sprintf(temp->mode, "%06o", mode);
 312 }
 313
 314 static void prepare_temp_file(const char *name,
 315                               struct diff_tempfile *temp,
 316                               struct diff_filespec *one)
 317 {
 318         if (!DIFF_FILE_VALID(one)) {
 319         not_a_valid_file:
 320                 /* A '-' entry produces this for file-2, and
 321                  * a '+' entry produces this for file-1.
 322                  */
 323                 temp->name = "/dev/null";
 324                 strcpy(temp->hex, ".");
 325                 strcpy(temp->mode, ".");
 326                 return;
 327         }
 328
 329         if (!one->sha1_valid ||
 330             work_tree_matches(name, one->sha1)) {
 331                 struct stat st;
 332                 if (lstat(name, &st) < 0) {
 333                         if (errno == ENOENT)
 334                                 goto not_a_valid_file;
 335                         die("stat(%s): %s", name, strerror(errno));
 336                 }
 337                 if (S_ISLNK(st.st_mode)) {
 338                         int ret;
 339                         char *buf, buf_[1024];
 340                         buf = ((sizeof(buf_) < st.st_size) ?
 341                                xmalloc(st.st_size) : buf_);
 342                         ret = readlink(name, buf, st.st_size);
 343                         if (ret < 0)
 344                                 die("readlink(%s)", name);
 345                         prep_temp_blob(temp, buf, st.st_size,
 346                                        (one->sha1_valid ?
 347                                         one->sha1 : null_sha1),
 348                                        (one->sha1_valid ?
 349                                         one->mode : S_IFLNK));
 350                 }
 351                 else {
 352                         /* we can borrow from the file in the work tree */
 353                         temp->name = name;
 354                         if (!one->sha1_valid)
 355                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
 356                         else
 357                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
 358                         sprintf(temp->mode, "%06o",
 359                                 S_IFREG |ce_permissions(st.st_mode));
 360                 }
 361                 return;
 362         }
 363         else {
 364                 if (diff_populate_filespec(one))
 365                         die("cannot read data blob for %s", one->path);
 366                 prep_temp_blob(temp, one->data, one->size,
 367                                one->sha1, one->mode);
 368         }
 369 }
 370
 371 static void remove_tempfile(void)
 372 {
 373         int i;
 374
 375         for (i = 0; i < 2; i++)
 376                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
 377                         unlink(diff_temp[i].name);
 378                         diff_temp[i].name = NULL;
 379                 }
 380 }
 381
 382 static void remove_tempfile_on_signal(int signo)
 383 {
 384         remove_tempfile();
 385 }
 386
 387 /* An external diff command takes:
 388  *
 389  * diff-cmd name infile1 infile1-sha1 infile1-mode \
 390  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
 391  *
 392  */
 393 static void run_external_diff(const char *pgm,
 394                               const char *name,
 395                               const char *other,
 396                               struct diff_filespec *one,
 397                               struct diff_filespec *two,
 398                               const char *xfrm_msg)
 399 {
 400         struct diff_tempfile *temp = diff_temp;
 401         pid_t pid;
 402         int status;
 403         static int atexit_asked = 0;
 404
 405         if (one && two) {
 406                 prepare_temp_file(name, &temp[0], one);
 407                 prepare_temp_file(other ? : name, &temp[1], two);
 408                 if (! atexit_asked &&
 409                     (temp[0].name == temp[0].tmp_path ||
 410                      temp[1].name == temp[1].tmp_path)) {
 411                         atexit_asked = 1;
 412                         atexit(remove_tempfile);
 413                 }
 414                 signal(SIGINT, remove_tempfile_on_signal);
 415         }
 416
 417         fflush(NULL);
 418         pid = fork();
 419         if (pid < 0)
 420                 die("unable to fork");
 421         if (!pid) {
 422                 if (pgm) {
 423                         if (one && two) {
 424                                 const char *exec_arg[10];
 425                                 const char **arg = &exec_arg[0];
 426                                 *arg++ = pgm;
 427                                 *arg++ = name;
 428                                 *arg++ = temp[0].name;
 429                                 *arg++ = temp[0].hex;
 430                                 *arg++ = temp[0].mode;
 431                                 *arg++ = temp[1].name;
 432                                 *arg++ = temp[1].hex;
 433                                 *arg++ = temp[1].mode;
 434                                 if (other) {
 435                                         *arg++ = other;
 436                                         *arg++ = xfrm_msg;
 437                                 }
 438                                 *arg = NULL;
 439                                 execvp(pgm, (char *const*) exec_arg);
 440                         }
 441                         else
 442                                 execlp(pgm, pgm, name, NULL);
 443                 }
 444                 /*
 445                  * otherwise we use the built-in one.
 446                  */
 447                 if (one && two)
 448                         builtin_diff(name, other ? : name, temp, xfrm_msg);
 449                 else
 450                         printf("* Unmerged path %s\n", name);
 451                 exit(0);
 452         }
 453         if (waitpid(pid, &status, 0) < 0 ||
 454             !WIFEXITED(status) || WEXITSTATUS(status)) {
 455                 /* Earlier we did not check the exit status because
 456                  * diff exits non-zero if files are different, and
 457                  * we are not interested in knowing that.  It was a
 458                  * mistake which made it harder to quit a diff-*
 459                  * session that uses the git-apply-patch-script as
 460                  * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
 461                  * should also exit non-zero only when it wants to
 462                  * abort the entire diff-* session.
 463                  */
 464                 remove_tempfile();
 465                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
 466                 exit(1);
 467         }
 468         remove_tempfile();
 469 }
 470
 471 static void run_diff(const char *name,
 472                      const char *other,
 473                      struct diff_filespec *one,
 474                      struct diff_filespec *two,
 475                      const char *xfrm_msg)
 476 {
 477         const char *pgm = external_diff();
 478         if (!pgm &&
 479             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
 480             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
 481                 /* a filepair that changes between file and symlink
 482                  * needs to be split into deletion and creation.
 483                  */
 484                 struct diff_filespec *null = alloc_filespec(two->path);
 485                 run_external_diff(NULL, name, other, one, null, xfrm_msg);
 486                 free(null);
 487                 null = alloc_filespec(one->path);
 488                 run_external_diff(NULL, name, other, null, two, xfrm_msg);
 489                 free(null);
 490         }
 491         else
 492                 run_external_diff(pgm, name, other, one, two, xfrm_msg);
 493 }
 494
 495 void diff_setup(int flags)
 496 {
 497         if (flags & DIFF_SETUP_REVERSE)
 498                 reverse_diff = 1;
 499 }
 500
 501 struct diff_queue_struct diff_queued_diff;
 502
 503 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
 504 {
 505         if (queue->alloc <= queue->nr) {
 506                 queue->alloc = alloc_nr(queue->alloc);
 507                 queue->queue = xrealloc(queue->queue,
 508                                         sizeof(dp) * queue->alloc);
 509         }
 510         queue->queue[queue->nr++] = dp;
 511 }
 512
 513 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
 514                                  struct diff_filespec *one,
 515                                  struct diff_filespec *two)
 516 {
 517         struct diff_filepair *dp = xmalloc(sizeof(*dp));
 518         dp->one = one;
 519         dp->two = two;
 520         dp->score = 0;
 521         dp->source_stays = 0;
 522         diff_q(queue, dp);
 523         return dp;
 524 }
 525
 526 void diff_free_filepair(struct diff_filepair *p)
 527 {
 528         diff_free_filespec_data(p->one);
 529         diff_free_filespec_data(p->two);
 530         free(p);
 531 }
 532
 533 static void diff_flush_raw(struct diff_filepair *p,
 534                            int line_termination,
 535                            int inter_name_termination)
 536 {
 537         int two_paths;
 538         char status[10];
 539
 540         if (line_termination) {
 541                 const char *err = "path %s cannot be expressed without -z";
 542                 if (strchr(p->one->path, line_termination) ||
 543                     strchr(p->one->path, inter_name_termination))
 544                         die(err, p->one->path);
 545                 if (strchr(p->two->path, line_termination) ||
 546                     strchr(p->two->path, inter_name_termination))
 547                         die(err, p->two->path);
 548         }
 549
 550         switch (p->status) {
 551         case 'C': case 'R':
 552                 two_paths = 1;
 553                 sprintf(status, "%c%03d", p->status,
 554                         (int)(0.5 + p->score * 100.0/MAX_SCORE));
 555                 break;
 556         default:
 557                 two_paths = 0;
 558                 status[0] = p->status;
 559                 status[1] = 0;
 560                 break;
 561         }
 562         printf(":%06o %06o %s ",
 563                p->one->mode, p->two->mode, sha1_to_hex(p->one->sha1));
 564         printf("%s %s%c%s",
 565                sha1_to_hex(p->two->sha1),
 566                status,
 567                inter_name_termination,
 568                p->one->path);
 569         if (two_paths)
 570                 printf("%c%s", inter_name_termination, p->two->path);
 571         putchar(line_termination);
 572 }
 573
 574 int diff_unmodified_pair(struct diff_filepair *p)
 575 {
 576         /* This function is written stricter than necessary to support
 577          * the currently implemented transformers, but the idea is to
 578          * let transformers to produce diff_filepairs any way they want,
 579          * and filter and clean them up here before producing the output.
 580          */
 581         struct diff_filespec *one, *two;
 582
 583         if (DIFF_PAIR_UNMERGED(p))
 584                 return 0; /* unmerged is interesting */
 585
 586         one = p->one;
 587         two = p->two;
 588
 589         /* deletion, addition, mode or type change
 590          * and rename are all interesting.
 591          */
 592         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
 593             DIFF_PAIR_MODE_CHANGED(p) ||
 594             strcmp(one->path, two->path))
 595                 return 0;
 596
 597         /* both are valid and point at the same path.  that is, we are
 598          * dealing with a change.
 599          */
 600         if (one->sha1_valid && two->sha1_valid &&
 601             !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
 602                 return 1; /* no change */
 603         if (!one->sha1_valid && !two->sha1_valid)
 604                 return 1; /* both look at the same file on the filesystem. */
 605         return 0;
 606 }
 607
 608 static void diff_flush_patch(struct diff_filepair *p)
 609 {
 610         const char *name, *other;
 611         char msg_[PATH_MAX*2+200], *msg;
 612
 613         if (diff_unmodified_pair(p))
 614                 return;
 615
 616         name = p->one->path;
 617         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
 618         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
 619             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
 620                 return; /* no tree diffs in patch format */
 621
 622         switch (p->status) {
 623         case 'C':
 624                 sprintf(msg_,
 625                         "similarity index %d%%\n"
 626                         "copy from %s\n"
 627                         "copy to %s",
 628                         (int)(0.5 + p->score * 100.0/MAX_SCORE),
 629                         p->one->path, p->two->path);
 630                 msg = msg_;
 631                 break;
 632         case 'R':
 633                 sprintf(msg_,
 634                         "similarity index %d%%\n"
 635                         "rename old %s\n"
 636                         "rename new %s",
 637                         (int)(0.5 + p->score * 100.0/MAX_SCORE),
 638                         p->one->path, p->two->path);
 639                 msg = msg_;
 640                 break;
 641         default:
 642                 msg = NULL;
 643         }
 644
 645         if (DIFF_PAIR_UNMERGED(p))
 646                 run_diff(name, NULL, NULL, NULL, NULL);
 647         else
 648                 run_diff(name, other, p->one, p->two, msg);
 649 }
 650
 651 int diff_queue_is_empty(void)
 652 {
 653         struct diff_queue_struct *q = &diff_queued_diff;
 654         int i;
 655         for (i = 0; i < q->nr; i++)
 656                 if (!diff_unmodified_pair(q->queue[i]))
 657                         return 0;
 658         return 1;
 659 }
 660
 661 #if DIFF_DEBUG
 662 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
 663 {
 664         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
 665                 x, one ? : "",
 666                 s->path,
 667                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
 668                 s->mode,
 669                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
 670         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
 671                 x, one ? : "",
 672                 s->size, s->xfrm_flags);
 673 }
 674
 675 void diff_debug_filepair(const struct diff_filepair *p, int i)
 676 {
 677         diff_debug_filespec(p->one, i, "one");
 678         diff_debug_filespec(p->two, i, "two");
 679         fprintf(stderr, "score %d, status %c source_stays %d\n",
 680                 p->score, p->status ? : '?', p->source_stays);
 681 }
 682
 683 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
 684 {
 685         int i;
 686         if (msg)
 687                 fprintf(stderr, "%s\n", msg);
 688         fprintf(stderr, "q->nr = %d\n", q->nr);
 689         for (i = 0; i < q->nr; i++) {
 690                 struct diff_filepair *p = q->queue[i];
 691                 diff_debug_filepair(p, i);
 692         }
 693 }
 694 #endif
 695
 696 static void diff_resolve_rename_copy(void)
 697 {
 698         int i, j;
 699         struct diff_filepair *p, *pp;
 700         struct diff_queue_struct *q = &diff_queued_diff;
 701
 702         diff_debug_queue("resolve-rename-copy", q);
 703
 704         for (i = 0; i < q->nr; i++) {
 705                 p = q->queue[i];
 706                 p->status = 0; /* undecided */
 707                 if (DIFF_PAIR_UNMERGED(p))
 708                         p->status = 'U';
 709                 else if (!DIFF_FILE_VALID(p->one))
 710                         p->status = 'N';
 711                 else if (!DIFF_FILE_VALID(p->two)) {
 712                         /* Deleted entry may have been picked up by
 713                          * another rename-copy entry.  So we scan the
 714                          * queue and if we find one that uses us as the
 715                          * source we do not say delete for this entry.
 716                          */
 717                         for (j = 0; j < q->nr; j++) {
 718                                 pp = q->queue[j];
 719                                 if (!strcmp(p->one->path, pp->one->path) &&
 720                                     pp->score) {
 721                                         /* rename/copy are always valid
 722                                          * so we do not say DIFF_FILE_VALID()
 723                                          * on pp->one and pp->two.
 724                                          */
 725                                         p->status = 'X';
 726                                         break;
 727                                 }
 728                         }
 729                         if (!p->status)
 730                                 p->status = 'D';
 731                 }
 732                 else if (DIFF_PAIR_TYPE_CHANGED(p))
 733                         p->status = 'T';
 734
 735                 /* from this point on, we are dealing with a pair
 736                  * whose both sides are valid and of the same type, i.e.
 737                  * either in-place edit or rename/copy edit.
 738                  */
 739                 else if (p->score) {
 740                         if (p->source_stays) {
 741                                 p->status = 'C';
 742                                 continue;
 743                         }
 744                         /* See if there is some other filepair that
 745                          * copies from the same source as us.  If so
 746                          * we are a copy.  Otherwise we are a rename.
 747                          */
 748                         for (j = i + 1; j < q->nr; j++) {
 749                                 pp = q->queue[j];
 750                                 if (strcmp(pp->one->path, p->one->path))
 751                                         continue; /* not us */
 752                                 if (!pp->score)
 753                                         continue; /* not a rename/copy */
 754                                 /* pp is a rename/copy from the same source */
 755                                 p->status = 'C';
 756                                 break;
 757                         }
 758                         if (!p->status)
 759                                 p->status = 'R';
 760                 }
 761                 else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
 762                          p->one->mode != p->two->mode)
 763                         p->status = 'M';
 764                 else
 765                         /* this is a "no-change" entry.
 766                          * should not happen anymore.
 767                          * p->status = 'X';
 768                          */
 769                         die("internal error in diffcore: unmodified entry remains");
 770         }
 771         diff_debug_queue("resolve-rename-copy done", q);
 772 }
 773
 774 void diff_flush(int diff_output_style, int resolve_rename_copy)
 775 {
 776         struct diff_queue_struct *q = &diff_queued_diff;
 777         int i;
 778         int line_termination = '\n';
 779         int inter_name_termination = '\t';
 780
 781         if (diff_output_style == DIFF_FORMAT_MACHINE)
 782                 line_termination = inter_name_termination = 0;
 783         if (resolve_rename_copy)
 784                 diff_resolve_rename_copy();
 785
 786         for (i = 0; i < q->nr; i++) {
 787                 struct diff_filepair *p = q->queue[i];
 788                 if ((diff_output_style == DIFF_FORMAT_NO_OUTPUT) ||
 789                     (p->status == 'X'))
 790                         continue;
 791                 if (p->status == 0)
 792                         die("internal error in diff-resolve-rename-copy");
 793                 switch (diff_output_style) {
 794                 case DIFF_FORMAT_PATCH:
 795                         diff_flush_patch(p);
 796                         break;
 797                 case DIFF_FORMAT_HUMAN:
 798                 case DIFF_FORMAT_MACHINE:
 799                         diff_flush_raw(p, line_termination,
 800                                        inter_name_termination);
 801                         break;
 802                 }
 803         }
 804         for (i = 0; i < q->nr; i++)
 805                 diff_free_filepair(q->queue[i]);
 806         free(q->queue);
 807         q->queue = NULL;
 808         q->nr = q->alloc = 0;
 809 }
 810
 811 void diff_addremove(int addremove, unsigned mode,
 812                     const unsigned char *sha1,
 813                     const char *base, const char *path)
 814 {
 815         char concatpath[PATH_MAX];
 816         struct diff_filespec *one, *two;
 817
 818         /* This may look odd, but it is a preparation for
 819          * feeding "there are unchanged files which should
 820          * not produce diffs, but when you are doing copy
 821          * detection you would need them, so here they are"
 822          * entries to the diff-core.  They will be prefixed
 823          * with something like '=' or '*' (I haven't decided
 824          * which but should not make any difference).
 825          * Feeding the same new and old to diff_change()
 826          * also has the same effect.
 827          * Before the final output happens, they are pruned after
 828          * merged into rename/copy pairs as appropriate.
 829          */
 830         if (reverse_diff)
 831                 addremove = (addremove == '+' ? '-' :
 832                              addremove == '-' ? '+' : addremove);
 833
 834         if (!path) path = "";
 835         sprintf(concatpath, "%s%s", base, path);
 836         one = alloc_filespec(concatpath);
 837         two = alloc_filespec(concatpath);
 838
 839         if (addremove != '+')
 840                 fill_filespec(one, sha1, mode);
 841         if (addremove != '-')
 842                 fill_filespec(two, sha1, mode);
 843
 844         diff_queue(&diff_queued_diff, one, two);
 845 }
 846
 847 void diff_helper_input(unsigned old_mode,
 848                        unsigned new_mode,
 849                        const unsigned char *old_sha1,
 850                        const unsigned char *new_sha1,
 851                        const char *old_path,
 852                        int status,
 853                        int score,
 854                        const char *new_path)
 855 {
 856         struct diff_filespec *one, *two;
 857         struct diff_filepair *dp;
 858
 859         one = alloc_filespec(old_path);
 860         two = alloc_filespec(new_path);
 861         if (old_mode)
 862                 fill_filespec(one, old_sha1, old_mode);
 863         if (new_mode)
 864                 fill_filespec(two, new_sha1, new_mode);
 865         dp = diff_queue(&diff_queued_diff, one, two);
 866         dp->score = score * MAX_SCORE / 100;
 867         dp->status = status;
 868 }
 869
 870 void diff_change(unsigned old_mode, unsigned new_mode,
 871                  const unsigned char *old_sha1,
 872                  const unsigned char *new_sha1,
 873                  const char *base, const char *path)
 874 {
 875         char concatpath[PATH_MAX];
 876         struct diff_filespec *one, *two;
 877
 878         if (reverse_diff) {
 879                 unsigned tmp;
 880                 const unsigned char *tmp_c;
 881                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
 882                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
 883         }
 884         if (!path) path = "";
 885         sprintf(concatpath, "%s%s", base, path);
 886         one = alloc_filespec(concatpath);
 887         two = alloc_filespec(concatpath);
 888         fill_filespec(one, old_sha1, old_mode);
 889         fill_filespec(two, new_sha1, new_mode);
 890
 891         diff_queue(&diff_queued_diff, one, two);
 892 }
 893
 894 void diff_unmerge(const char *path)
 895 {
 896         struct diff_filespec *one, *two;
 897         one = alloc_filespec(path);
 898         two = alloc_filespec(path);
 899         diff_queue(&diff_queued_diff, one, two);
 900 }