merge-recursive.c

   1 /*
   2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
   3  * Fredrik Kuivinen.
   4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
   5  */
   6 #include <stdarg.h>
   7 #include <string.h>
   8 #include <assert.h>
   9 #include <sys/wait.h>
  10 #include <sys/types.h>
  11 #include <sys/stat.h>
  12 #include <time.h>
  13 #include "cache.h"
  14 #include "cache-tree.h"
  15 #include "commit.h"
  16 #include "blob.h"
  17 #include "tree-walk.h"
  18 #include "diff.h"
  19 #include "diffcore.h"
  20 #include "run-command.h"
  21 #include "tag.h"
  22
  23 #include "path-list.h"
  24
  25 /*#define DEBUG*/
  26
  27 #ifdef DEBUG
  28 #define debug(...) fprintf(stderr, __VA_ARGS__)
  29 #else
  30 #define debug(...) do { ; /* nothing */ } while (0)
  31 #endif
  32
  33 #ifdef DEBUG
  34 #include "quote.h"
  35 static void show_ce_entry(const char *tag, struct cache_entry *ce)
  36 {
  37         if (tag && *tag &&
  38             (ce->ce_flags & htons(CE_VALID))) {
  39                 static char alttag[4];
  40                 memcpy(alttag, tag, 3);
  41                 if (isalpha(tag[0]))
  42                         alttag[0] = tolower(tag[0]);
  43                 else if (tag[0] == '?')
  44                         alttag[0] = '!';
  45                 else {
  46                         alttag[0] = 'v';
  47                         alttag[1] = tag[0];
  48                         alttag[2] = ' ';
  49                         alttag[3] = 0;
  50                 }
  51                 tag = alttag;
  52         }
  53
  54         fprintf(stderr,"%s%06o %s %d\t",
  55                         tag,
  56                         ntohl(ce->ce_mode),
  57                         sha1_to_hex(ce->sha1),
  58                         ce_stage(ce));
  59         write_name_quoted("", 0, ce->name,
  60                         '\n', stderr);
  61         fputc('\n', stderr);
  62 }
  63
  64 static void ls_files(void) {
  65         int i;
  66         for (i = 0; i < active_nr; i++) {
  67                 struct cache_entry *ce = active_cache[i];
  68                 show_ce_entry("", ce);
  69         }
  70         fprintf(stderr, "---\n");
  71         if (0) ls_files(); /* avoid "unused" warning */
  72 }
  73 #endif
  74
  75 /*
  76  * A virtual commit has
  77  * - (const char *)commit->util set to the name, and
  78  * - *(int *)commit->object.sha1 set to the virtual id.
  79  */
  80
  81 static unsigned commit_list_count(const struct commit_list *l)
  82 {
  83         unsigned c = 0;
  84         for (; l; l = l->next )
  85                 c++;
  86         return c;
  87 }
  88
  89 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  90 {
  91         struct commit *commit = xcalloc(1, sizeof(struct commit));
  92         static unsigned virtual_id = 1;
  93         commit->tree = tree;
  94         commit->util = (void*)comment;
  95         *(int*)commit->object.sha1 = virtual_id++;
  96         return commit;
  97 }
  98
  99 /*
 100  * TODO: we should not have to copy the SHA1s around, but rather reference
 101  * them. That way, sha_eq() is just sha1 == sha2.
 102  */
 103 static int sha_eq(const unsigned char *a, const unsigned char *b)
 104 {
 105         if (!a && !b)
 106                 return 2;
 107         return a && b && memcmp(a, b, 20) == 0;
 108 }
 109
 110 /*
 111  * TODO: check if we can just reuse the active_cache structure: it is already
 112  * sorted (by name, stage).
 113  * Only problem: do not write it when flushing the cache.
 114  */
 115 struct stage_data
 116 {
 117         struct
 118         {
 119                 unsigned mode;
 120                 unsigned char sha[20];
 121         } stages[4];
 122         unsigned processed:1;
 123 };
 124
 125 static struct path_list currentFileSet = {NULL, 0, 0, 1};
 126 static struct path_list currentDirectorySet = {NULL, 0, 0, 1};
 127
 128 static int output_indent = 0;
 129
 130 static void output(const char *fmt, ...)
 131 {
 132         va_list args;
 133         int i;
 134         for (i = output_indent; i--;)
 135                 fputs("  ", stdout);
 136         va_start(args, fmt);
 137         vfprintf(stdout, fmt, args);
 138         va_end(args);
 139         fputc('\n', stdout);
 140 }
 141
 142 static void output_commit_title(struct commit *commit)
 143 {
 144         int i;
 145         for (i = output_indent; i--;)
 146                 fputs("  ", stdout);
 147         if (commit->util)
 148                 printf("virtual %s\n", (char *)commit->util);
 149         else {
 150                 printf("%s ", sha1_to_hex(commit->object.sha1));
 151                 if (parse_commit(commit) != 0)
 152                         printf("(bad commit)\n");
 153                 else {
 154                         const char *s;
 155                         int len;
 156                         for (s = commit->buffer; *s; s++)
 157                                 if (*s == '\n' && s[1] == '\n') {
 158                                         s += 2;
 159                                         break;
 160                                 }
 161                         for (len = 0; s[len] && '\n' != s[len]; len++)
 162                                 ; /* do nothing */
 163                         printf("%.*s\n", len, s);
 164                 }
 165         }
 166 }
 167
 168 static const char *original_index_file;
 169 static const char *temporary_index_file;
 170 static int cache_dirty = 0;
 171
 172 static int flush_cache(void)
 173 {
 174         /* flush temporary index */
 175         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 176         int fd = hold_lock_file_for_update(lock, getenv("GIT_INDEX_FILE"));
 177         if (fd < 0)
 178                 die("could not lock %s", temporary_index_file);
 179         if (write_cache(fd, active_cache, active_nr) ||
 180                         close(fd) || commit_lock_file(lock))
 181                 die ("unable to write %s", getenv("GIT_INDEX_FILE"));
 182         discard_cache();
 183         cache_dirty = 0;
 184         return 0;
 185 }
 186
 187 static void setup_index(int temp)
 188 {
 189         const char *idx = temp ? temporary_index_file: original_index_file;
 190         if (cache_dirty)
 191                 die("fatal: cache changed flush_cache();");
 192         unlink(temporary_index_file);
 193         setenv("GIT_INDEX_FILE", idx, 1);
 194         discard_cache();
 195 }
 196
 197 static struct cache_entry *make_cache_entry(unsigned int mode,
 198                 const unsigned char *sha1, const char *path, int stage, int refresh)
 199 {
 200         int size, len;
 201         struct cache_entry *ce;
 202
 203         if (!verify_path(path))
 204                 return NULL;
 205
 206         len = strlen(path);
 207         size = cache_entry_size(len);
 208         ce = xcalloc(1, size);
 209
 210         memcpy(ce->sha1, sha1, 20);
 211         memcpy(ce->name, path, len);
 212         ce->ce_flags = create_ce_flags(len, stage);
 213         ce->ce_mode = create_ce_mode(mode);
 214
 215         if (refresh)
 216                 return refresh_cache_entry(ce, 0);
 217
 218         return ce;
 219 }
 220
 221 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 222                 const char *path, int stage, int refresh, int options)
 223 {
 224         struct cache_entry *ce;
 225         if (!cache_dirty)
 226                 read_cache_from(getenv("GIT_INDEX_FILE"));
 227         cache_dirty++;
 228         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 229         if (!ce)
 230                 return error("cache_addinfo failed: %s", strerror(cache_errno));
 231         return add_cache_entry(ce, options);
 232 }
 233
 234 /*
 235  * This is a global variable which is used in a number of places but
 236  * only written to in the 'merge' function.
 237  *
 238  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
 239  *                       don't update the working directory.
 240  *               0    => Leave unmerged entries in the cache and update
 241  *                       the working directory.
 242  */
 243 static int index_only = 0;
 244
 245 /*
 246  * TODO: this can be streamlined by refactoring builtin-read-tree.c
 247  */
 248 static int git_read_tree(const struct tree *tree)
 249 {
 250 #if 0
 251         fprintf(stderr, "GIT_INDEX_FILE='%s' git-read-tree %s\n",
 252                 getenv("GIT_INDEX_FILE"),
 253                 sha1_to_hex(tree->object.sha1));
 254 #endif
 255         int rc;
 256         const char *argv[] = { "git-read-tree", NULL, NULL, };
 257         if (cache_dirty)
 258                 die("read-tree with dirty cache");
 259         argv[1] = sha1_to_hex(tree->object.sha1);
 260         rc = run_command_v(2, argv);
 261         return rc < 0 ? -1: rc;
 262 }
 263
 264 /*
 265  * TODO: this can be streamlined by refactoring builtin-read-tree.c
 266  */
 267 static int git_merge_trees(const char *update_arg,
 268                            struct tree *common,
 269                            struct tree *head,
 270                            struct tree *merge)
 271 {
 272 #if 0
 273         fprintf(stderr, "GIT_INDEX_FILE='%s' git-read-tree %s -m %s %s %s\n",
 274                 getenv("GIT_INDEX_FILE"),
 275                 update_arg,
 276                 sha1_to_hex(common->object.sha1),
 277                 sha1_to_hex(head->object.sha1),
 278                 sha1_to_hex(merge->object.sha1));
 279 #endif
 280         int rc;
 281         const char *argv[] = {
 282                 "git-read-tree", NULL, "-m", NULL, NULL, NULL,
 283                 NULL,
 284         };
 285         if (cache_dirty)
 286                 flush_cache();
 287         argv[1] = update_arg;
 288         argv[3] = sha1_to_hex(common->object.sha1);
 289         argv[4] = sha1_to_hex(head->object.sha1);
 290         argv[5] = sha1_to_hex(merge->object.sha1);
 291         rc = run_command_v(6, argv);
 292         return rc < 0 ? -1: rc;
 293 }
 294
 295 /*
 296  * TODO: this can be streamlined by refactoring builtin-write-tree.c
 297  */
 298 static struct tree *git_write_tree(void)
 299 {
 300 #if 0
 301         fprintf(stderr, "GIT_INDEX_FILE='%s' git-write-tree\n",
 302                 getenv("GIT_INDEX_FILE"));
 303 #endif
 304         FILE *fp;
 305         int rc;
 306         char buf[41];
 307         unsigned char sha1[20];
 308         int ch;
 309         unsigned i = 0;
 310         if (cache_dirty)
 311                 flush_cache();
 312         fp = popen("git-write-tree 2>/dev/null", "r");
 313         while ((ch = fgetc(fp)) != EOF)
 314                 if (i < sizeof(buf)-1 && ch >= '0' && ch <= 'f')
 315                         buf[i++] = ch;
 316                 else
 317                         break;
 318         rc = pclose(fp);
 319         if (rc == -1 || WEXITSTATUS(rc))
 320                 return NULL;
 321         buf[i] = '\0';
 322         if (get_sha1(buf, sha1) != 0)
 323                 return NULL;
 324         return lookup_tree(sha1);
 325 }
 326
 327 static int save_files_dirs(const unsigned char *sha1,
 328                 const char *base, int baselen, const char *path,
 329                 unsigned int mode, int stage)
 330 {
 331         int len = strlen(path);
 332         char *newpath = malloc(baselen + len + 1);
 333         memcpy(newpath, base, baselen);
 334         memcpy(newpath + baselen, path, len);
 335         newpath[baselen + len] = '\0';
 336
 337         if (S_ISDIR(mode))
 338                 path_list_insert(newpath, &currentDirectorySet);
 339         else
 340                 path_list_insert(newpath, &currentFileSet);
 341         free(newpath);
 342
 343         return READ_TREE_RECURSIVE;
 344 }
 345
 346 static int get_files_dirs(struct tree *tree)
 347 {
 348         int n;
 349         debug("get_files_dirs ...\n");
 350         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0) {
 351                 debug("  get_files_dirs done (0)\n");
 352                 return 0;
 353         }
 354         n = currentFileSet.nr + currentDirectorySet.nr;
 355         debug("  get_files_dirs done (%d)\n", n);
 356         return n;
 357 }
 358
 359 /*
 360  * Returns a index_entry instance which doesn't have to correspond to
 361  * a real cache entry in Git's index.
 362  */
 363 static struct stage_data *insert_stage_data(const char *path,
 364                 struct tree *o, struct tree *a, struct tree *b,
 365                 struct path_list *entries)
 366 {
 367         struct path_list_item *item;
 368         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 369         get_tree_entry(o->object.sha1, path,
 370                         e->stages[1].sha, &e->stages[1].mode);
 371         get_tree_entry(a->object.sha1, path,
 372                         e->stages[2].sha, &e->stages[2].mode);
 373         get_tree_entry(b->object.sha1, path,
 374                         e->stages[3].sha, &e->stages[3].mode);
 375         item = path_list_insert(path, entries);
 376         item->util = e;
 377         return e;
 378 }
 379
 380 /*
 381  * Create a dictionary mapping file names to CacheEntry objects. The
 382  * dictionary contains one entry for every path with a non-zero stage entry.
 383  */
 384 static struct path_list *get_unmerged(void)
 385 {
 386         struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
 387         int i;
 388
 389         unmerged->strdup_paths = 1;
 390         if (!cache_dirty) {
 391                 read_cache_from(getenv("GIT_INDEX_FILE"));
 392                 cache_dirty++;
 393         }
 394         for (i = 0; i < active_nr; i++) {
 395                 struct path_list_item *item;
 396                 struct stage_data *e;
 397                 struct cache_entry *ce = active_cache[i];
 398                 if (!ce_stage(ce))
 399                         continue;
 400
 401                 item = path_list_lookup(ce->name, unmerged);
 402                 if (!item) {
 403                         item = path_list_insert(ce->name, unmerged);
 404                         item->util = xcalloc(1, sizeof(struct stage_data));
 405                 }
 406                 e = item->util;
 407                 e->stages[ce_stage(ce)].mode = ntohl(ce->ce_mode);
 408                 memcpy(e->stages[ce_stage(ce)].sha, ce->sha1, 20);
 409         }
 410
 411         return unmerged;
 412 }
 413
 414 struct rename
 415 {
 416         struct diff_filepair *pair;
 417         struct stage_data *src_entry;
 418         struct stage_data *dst_entry;
 419         unsigned processed:1;
 420 };
 421
 422 /*
 423  * Get information of all renames which occured between 'oTree' and
 424  * 'tree'. We need the three trees in the merge ('oTree', 'aTree' and
 425  * 'bTree') to be able to associate the correct cache entries with
 426  * the rename information. 'tree' is always equal to either aTree or bTree.
 427  */
 428 static struct path_list *get_renames(struct tree *tree,
 429                                         struct tree *oTree,
 430                                         struct tree *aTree,
 431                                         struct tree *bTree,
 432                                         struct path_list *entries)
 433 {
 434         int i;
 435         struct path_list *renames;
 436         struct diff_options opts;
 437 #ifdef DEBUG
 438         time_t t = time(0);
 439
 440         debug("getRenames ...\n");
 441 #endif
 442
 443         renames = xcalloc(1, sizeof(struct path_list));
 444         diff_setup(&opts);
 445         opts.recursive = 1;
 446         opts.detect_rename = DIFF_DETECT_RENAME;
 447         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 448         if (diff_setup_done(&opts) < 0)
 449                 die("diff setup failed");
 450         diff_tree_sha1(oTree->object.sha1, tree->object.sha1, "", &opts);
 451         diffcore_std(&opts);
 452         for (i = 0; i < diff_queued_diff.nr; ++i) {
 453                 struct path_list_item *item;
 454                 struct rename *re;
 455                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 456                 if (pair->status != 'R') {
 457                         diff_free_filepair(pair);
 458                         continue;
 459                 }
 460                 re = xmalloc(sizeof(*re));
 461                 re->processed = 0;
 462                 re->pair = pair;
 463                 item = path_list_lookup(re->pair->one->path, entries);
 464                 if (!item)
 465                         re->src_entry = insert_stage_data(re->pair->one->path,
 466                                         oTree, aTree, bTree, entries);
 467                 else
 468                         re->src_entry = item->util;
 469
 470                 item = path_list_lookup(re->pair->two->path, entries);
 471                 if (!item)
 472                         re->dst_entry = insert_stage_data(re->pair->two->path,
 473                                         oTree, aTree, bTree, entries);
 474                 else
 475                         re->dst_entry = item->util;
 476                 item = path_list_insert(pair->one->path, renames);
 477                 item->util = re;
 478         }
 479         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 480         diff_queued_diff.nr = 0;
 481         diff_flush(&opts);
 482 #ifdef DEBUG
 483         debug("  getRenames done in %ld\n", time(0)-t);
 484 #endif
 485         return renames;
 486 }
 487
 488 int update_stages(const char *path, struct diff_filespec *o,
 489                 struct diff_filespec *a, struct diff_filespec *b, int clear)
 490 {
 491         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 492         if (clear)
 493                 if (remove_file_from_cache(path))
 494                         return -1;
 495         if (o)
 496                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 497                         return -1;
 498         if (a)
 499                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 500                         return -1;
 501         if (b)
 502                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 503                         return -1;
 504         return 0;
 505 }
 506
 507 static int remove_path(const char *name)
 508 {
 509         int ret, len;
 510         char *slash, *dirs;
 511
 512         ret = unlink(name);
 513         if (ret)
 514                 return ret;
 515         len = strlen(name);
 516         dirs = malloc(len+1);
 517         memcpy(dirs, name, len);
 518         dirs[len] = '\0';
 519         while ((slash = strrchr(name, '/'))) {
 520                 *slash = '\0';
 521                 len = slash - name;
 522                 if (rmdir(name) != 0)
 523                         break;
 524         }
 525         free(dirs);
 526         return ret;
 527 }
 528
 529 /* General TODO: unC99ify the code: no declaration after code */
 530 /* General TODO: no javaIfiCation: rename updateCache to update_cache */
 531 /*
 532  * TODO: once we no longer call external programs, we'd probably be better off
 533  * not setting / getting the environment variable GIT_INDEX_FILE all the time.
 534  */
 535 int remove_file(int clean, const char *path)
 536 {
 537         int updateCache = index_only || clean;
 538         int updateWd = !index_only;
 539
 540         if (updateCache) {
 541                 if (!cache_dirty)
 542                         read_cache_from(getenv("GIT_INDEX_FILE"));
 543                 cache_dirty++;
 544                 if (remove_file_from_cache(path))
 545                         return -1;
 546         }
 547         if (updateWd)
 548         {
 549                 unlink(path);
 550                 if (errno != ENOENT || errno != EISDIR)
 551                         return -1;
 552                 remove_path(path);
 553         }
 554         return 0;
 555 }
 556
 557 static char *unique_path(const char *path, const char *branch)
 558 {
 559         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 560         int suffix = 0;
 561         struct stat st;
 562         char *p = newpath + strlen(newpath);
 563         strcpy(newpath, path);
 564         strcat(newpath, "~");
 565         strcpy(p, branch);
 566         for (; *p; ++p)
 567                 if ('/' == *p)
 568                         *p = '_';
 569         while (path_list_has_path(&currentFileSet, newpath) ||
 570                path_list_has_path(&currentDirectorySet, newpath) ||
 571                lstat(newpath, &st) == 0)
 572                 sprintf(p, "_%d", suffix++);
 573
 574         path_list_insert(newpath, &currentFileSet);
 575         return newpath;
 576 }
 577
 578 static int mkdir_p(const char *path, unsigned long mode)
 579 {
 580         /* path points to cache entries, so strdup before messing with it */
 581         char *buf = strdup(path);
 582         int result = safe_create_leading_directories(buf);
 583         free(buf);
 584         return result;
 585 }
 586
 587 static void flush_buffer(int fd, const char *buf, unsigned long size)
 588 {
 589         while (size > 0) {
 590                 long ret = xwrite(fd, buf, size);
 591                 if (ret < 0) {
 592                         /* Ignore epipe */
 593                         if (errno == EPIPE)
 594                                 break;
 595                         die("merge-recursive: %s", strerror(errno));
 596                 } else if (!ret) {
 597                         die("merge-recursive: disk full?");
 598                 }
 599                 size -= ret;
 600                 buf += ret;
 601         }
 602 }
 603
 604 void update_file_flags(const unsigned char *sha,
 605                        unsigned mode,
 606                        const char *path,
 607                        int update_cache,
 608                        int update_wd)
 609 {
 610         if (index_only)
 611                 update_wd = 0;
 612
 613         if (update_wd) {
 614                 char type[20];
 615                 void *buf;
 616                 unsigned long size;
 617
 618                 buf = read_sha1_file(sha, type, &size);
 619                 if (!buf)
 620                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 621                 if (strcmp(type, blob_type) != 0)
 622                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 623
 624                 if (S_ISREG(mode)) {
 625                         int fd;
 626                         if (mkdir_p(path, 0777))
 627                                 die("failed to create path %s: %s", path, strerror(errno));
 628                         unlink(path);
 629                         if (mode & 0100)
 630                                 mode = 0777;
 631                         else
 632                                 mode = 0666;
 633                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 634                         if (fd < 0)
 635                                 die("failed to open %s: %s", path, strerror(errno));
 636                         flush_buffer(fd, buf, size);
 637                         close(fd);
 638                 } else if (S_ISLNK(mode)) {
 639                         char *lnk = malloc(size + 1);
 640                         memcpy(lnk, buf, size);
 641                         lnk[size] = '\0';
 642                         mkdir_p(path, 0777);
 643                         unlink(lnk);
 644                         symlink(lnk, path);
 645                 } else
 646                         die("do not know what to do with %06o %s '%s'",
 647                             mode, sha1_to_hex(sha), path);
 648         }
 649         if (update_cache)
 650                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 651 }
 652
 653 void update_file(int clean,
 654                 const unsigned char *sha,
 655                 unsigned mode,
 656                 const char *path)
 657 {
 658         update_file_flags(sha, mode, path, index_only || clean, !index_only);
 659 }
 660
 661 /* Low level file merging, update and removal */
 662
 663 struct merge_file_info
 664 {
 665         unsigned char sha[20];
 666         unsigned mode;
 667         unsigned clean:1,
 668                  merge:1;
 669 };
 670
 671 static char *git_unpack_file(const unsigned char *sha1, char *path)
 672 {
 673         void *buf;
 674         char type[20];
 675         unsigned long size;
 676         int fd;
 677
 678         buf = read_sha1_file(sha1, type, &size);
 679         if (!buf || strcmp(type, blob_type))
 680                 die("unable to read blob object %s", sha1_to_hex(sha1));
 681
 682         strcpy(path, ".merge_file_XXXXXX");
 683         fd = mkstemp(path);
 684         if (fd < 0)
 685                 die("unable to create temp-file");
 686         flush_buffer(fd, buf, size);
 687         close(fd);
 688         return path;
 689 }
 690
 691 static struct merge_file_info merge_file(struct diff_filespec *o,
 692                 struct diff_filespec *a, struct diff_filespec *b,
 693                 const char *branch1Name, const char *branch2Name)
 694 {
 695         struct merge_file_info result;
 696         result.merge = 0;
 697         result.clean = 1;
 698
 699         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 700                 result.clean = 0;
 701                 if (S_ISREG(a->mode)) {
 702                         result.mode = a->mode;
 703                         memcpy(result.sha, a->sha1, 20);
 704                 } else {
 705                         result.mode = b->mode;
 706                         memcpy(result.sha, b->sha1, 20);
 707                 }
 708         } else {
 709                 if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
 710                         result.merge = 1;
 711
 712                 result.mode = a->mode == o->mode ? b->mode: a->mode;
 713
 714                 if (sha_eq(a->sha1, o->sha1))
 715                         memcpy(result.sha, b->sha1, 20);
 716                 else if (sha_eq(b->sha1, o->sha1))
 717                         memcpy(result.sha, a->sha1, 20);
 718                 else if (S_ISREG(a->mode)) {
 719                         int code = 1, fd;
 720                         struct stat st;
 721                         char orig[PATH_MAX];
 722                         char src1[PATH_MAX];
 723                         char src2[PATH_MAX];
 724                         const char *argv[] = {
 725                                 "merge", "-L", NULL, "-L", NULL, "-L", NULL,
 726                                 src1, orig, src2,
 727                                 NULL
 728                         };
 729                         char *la, *lb, *lo;
 730
 731                         git_unpack_file(o->sha1, orig);
 732                         git_unpack_file(a->sha1, src1);
 733                         git_unpack_file(b->sha1, src2);
 734
 735                         argv[2] = la = strdup(mkpath("%s/%s", branch1Name, a->path));
 736                         argv[6] = lb = strdup(mkpath("%s/%s", branch2Name, b->path));
 737                         argv[4] = lo = strdup(mkpath("orig/%s", o->path));
 738
 739 #if 0
 740                         printf("%s %s %s %s %s %s %s %s %s %s\n",
 741                                argv[0], argv[1], argv[2], argv[3], argv[4],
 742                                argv[5], argv[6], argv[7], argv[8], argv[9]);
 743 #endif
 744                         code = run_command_v(10, argv);
 745
 746                         free(la);
 747                         free(lb);
 748                         free(lo);
 749                         if (code && code < -256) {
 750                                 die("Failed to execute 'merge'. merge(1) is used as the "
 751                                     "file-level merge tool. Is 'merge' in your path?");
 752                         }
 753                         fd = open(src1, O_RDONLY);
 754                         if (fd < 0 || fstat(fd, &st) < 0 ||
 755                                         index_fd(result.sha, fd, &st, 1,
 756                                                 "blob"))
 757                                 die("Unable to add %s to database", src1);
 758
 759                         unlink(orig);
 760                         unlink(src1);
 761                         unlink(src2);
 762
 763                         result.clean = WEXITSTATUS(code) == 0;
 764                 } else {
 765                         if (!(S_ISLNK(a->mode) || S_ISLNK(b->mode)))
 766                                 die("cannot merge modes?");
 767
 768                         memcpy(result.sha, a->sha1, 20);
 769
 770                         if (!sha_eq(a->sha1, b->sha1))
 771                                 result.clean = 0;
 772                 }
 773         }
 774
 775         return result;
 776 }
 777
 778 static void conflict_rename_rename(struct rename *ren1,
 779                                    const char *branch1,
 780                                    struct rename *ren2,
 781                                    const char *branch2)
 782 {
 783         char *del[2];
 784         int delp = 0;
 785         const char *ren1_dst = ren1->pair->two->path;
 786         const char *ren2_dst = ren2->pair->two->path;
 787         const char *dstName1 = ren1_dst;
 788         const char *dstName2 = ren2_dst;
 789         if (path_list_has_path(&currentDirectorySet, ren1_dst)) {
 790                 dstName1 = del[delp++] = unique_path(ren1_dst, branch1);
 791                 output("%s is a directory in %s adding as %s instead",
 792                        ren1_dst, branch2, dstName1);
 793                 remove_file(0, ren1_dst);
 794         }
 795         if (path_list_has_path(&currentDirectorySet, ren2_dst)) {
 796                 dstName2 = del[delp++] = unique_path(ren2_dst, branch2);
 797                 output("%s is a directory in %s adding as %s instead",
 798                        ren2_dst, branch1, dstName2);
 799                 remove_file(0, ren2_dst);
 800         }
 801         update_stages(dstName1, NULL, ren1->pair->two, NULL, 1);
 802         update_stages(dstName2, NULL, NULL, ren2->pair->two, 1);
 803         while (delp--)
 804                 free(del[delp]);
 805 }
 806
 807 static void conflict_rename_dir(struct rename *ren1,
 808                                 const char *branch1)
 809 {
 810         char *newPath = unique_path(ren1->pair->two->path, branch1);
 811         output("Renaming %s to %s instead", ren1->pair->one->path, newPath);
 812         remove_file(0, ren1->pair->two->path);
 813         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, newPath);
 814         free(newPath);
 815 }
 816
 817 static void conflict_rename_rename_2(struct rename *ren1,
 818                                      const char *branch1,
 819                                      struct rename *ren2,
 820                                      const char *branch2)
 821 {
 822         char *newPath1 = unique_path(ren1->pair->two->path, branch1);
 823         char *newPath2 = unique_path(ren2->pair->two->path, branch2);
 824         output("Renaming %s to %s and %s to %s instead",
 825                ren1->pair->one->path, newPath1,
 826                ren2->pair->one->path, newPath2);
 827         remove_file(0, ren1->pair->two->path);
 828         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, newPath1);
 829         update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, newPath2);
 830         free(newPath2);
 831         free(newPath1);
 832 }
 833
 834 /* General TODO: get rid of all the debug messages */
 835 static int process_renames(struct path_list *renamesA,
 836                            struct path_list *renamesB,
 837                            const char *branchNameA,
 838                            const char *branchNameB)
 839 {
 840         int cleanMerge = 1, i, j;
 841         struct path_list byDstA = {NULL, 0, 0, 0}, byDstB = {NULL, 0, 0, 0};
 842         const struct rename *sre;
 843
 844         for (i = 0; i < renamesA->nr; i++) {
 845                 sre = renamesA->items[i].util;
 846                 path_list_insert(sre->pair->two->path, &byDstA)->util
 847                         = sre->dst_entry;
 848         }
 849         for (i = 0; i < renamesB->nr; i++) {
 850                 sre = renamesB->items[i].util;
 851                 path_list_insert(sre->pair->two->path, &byDstB)->util
 852                         = sre->dst_entry;
 853         }
 854
 855         for (i = 0, j = 0; i < renamesA->nr || j < renamesB->nr;) {
 856                 int compare;
 857                 char *src;
 858                 struct path_list *renames1, *renames2, *renames2Dst;
 859                 struct rename *ren1 = NULL, *ren2 = NULL;
 860                 const char *branchName1, *branchName2;
 861                 const char *ren1_src, *ren1_dst;
 862
 863                 if (i >= renamesA->nr) {
 864                         compare = 1;
 865                         ren2 = renamesB->items[j++].util;
 866                 } else if (j >= renamesB->nr) {
 867                         compare = -1;
 868                         ren1 = renamesA->items[i++].util;
 869                 } else {
 870                         compare = strcmp(renamesA->items[i].path,
 871                                         renamesB->items[j].path);
 872                         ren1 = renamesA->items[i++].util;
 873                         ren2 = renamesB->items[j++].util;
 874                 }
 875
 876                 /* TODO: refactor, so that 1/2 are not needed */
 877                 if (ren1) {
 878                         renames1 = renamesA;
 879                         renames2 = renamesB;
 880                         renames2Dst = &byDstB;
 881                         branchName1 = branchNameA;
 882                         branchName2 = branchNameB;
 883                 } else {
 884                         struct rename *tmp;
 885                         renames1 = renamesB;
 886                         renames2 = renamesA;
 887                         renames2Dst = &byDstA;
 888                         branchName1 = branchNameB;
 889                         branchName2 = branchNameA;
 890                         tmp = ren2;
 891                         ren2 = ren1;
 892                         ren1 = tmp;
 893                 }
 894                 src = ren1->pair->one->path;
 895
 896                 ren1->dst_entry->processed = 1;
 897                 ren1->src_entry->processed = 1;
 898
 899                 if (ren1->processed)
 900                         continue;
 901                 ren1->processed = 1;
 902
 903                 ren1_src = ren1->pair->one->path;
 904                 ren1_dst = ren1->pair->two->path;
 905
 906                 if (ren2) {
 907                         const char *ren2_src = ren2->pair->one->path;
 908                         const char *ren2_dst = ren2->pair->two->path;
 909                         /* Renamed in 1 and renamed in 2 */
 910                         if (strcmp(ren1_src, ren2_src) != 0)
 911                                 die("ren1.src != ren2.src");
 912                         ren2->dst_entry->processed = 1;
 913                         ren2->processed = 1;
 914                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 915                                 cleanMerge = 0;
 916                                 output("CONFLICT (rename/rename): "
 917                                        "Rename %s->%s in branch %s "
 918                                        "rename %s->%s in %s",
 919                                        src, ren1_dst, branchName1,
 920                                        src, ren2_dst, branchName2);
 921                                 conflict_rename_rename(ren1, branchName1, ren2, branchName2);
 922                         } else {
 923                                 remove_file(1, ren1_src);
 924                                 struct merge_file_info mfi;
 925                                 mfi = merge_file(ren1->pair->one,
 926                                                  ren1->pair->two,
 927                                                  ren2->pair->two,
 928                                                  branchName1,
 929                                                  branchName2);
 930                                 if (mfi.merge || !mfi.clean)
 931                                         output("Renaming %s->%s", src, ren1_dst);
 932
 933                                 if (mfi.merge)
 934                                         output("Auto-merging %s", ren1_dst);
 935
 936                                 if (!mfi.clean) {
 937                                         output("CONFLICT (content): merge conflict in %s",
 938                                                ren1_dst);
 939                                         cleanMerge = 0;
 940
 941                                         if (!index_only)
 942                                                 update_stages(ren1_dst,
 943                                                               ren1->pair->one,
 944                                                               ren1->pair->two,
 945                                                               ren2->pair->two,
 946                                                               1 /* clear */);
 947                                 }
 948                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 949                         }
 950                 } else {
 951                         /* Renamed in 1, maybe changed in 2 */
 952                         struct path_list_item *item;
 953                         /* we only use sha1 and mode of these */
 954                         struct diff_filespec src_other, dst_other;
 955                         int tryMerge, stage = renamesA == renames1 ? 3: 2;
 956
 957                         remove_file(1, ren1_src);
 958
 959                         memcpy(src_other.sha1,
 960                                         ren1->src_entry->stages[stage].sha, 20);
 961                         src_other.mode = ren1->src_entry->stages[stage].mode;
 962                         memcpy(dst_other.sha1,
 963                                         ren1->dst_entry->stages[stage].sha, 20);
 964                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 965
 966                         tryMerge = 0;
 967
 968                         if (path_list_has_path(&currentDirectorySet, ren1_dst)) {
 969                                 cleanMerge = 0;
 970                                 output("CONFLICT (rename/directory): Rename %s->%s in %s "
 971                                        " directory %s added in %s",
 972                                        ren1_src, ren1_dst, branchName1,
 973                                        ren1_dst, branchName2);
 974                                 conflict_rename_dir(ren1, branchName1);
 975                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 976                                 cleanMerge = 0;
 977                                 output("CONFLICT (rename/delete): Rename %s->%s in %s "
 978                                        "and deleted in %s",
 979                                        ren1_src, ren1_dst, branchName1,
 980                                        branchName2);
 981                                 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 982                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 983                                 const char *newPath;
 984                                 cleanMerge = 0;
 985                                 tryMerge = 1;
 986                                 output("CONFLICT (rename/add): Rename %s->%s in %s. "
 987                                        "%s added in %s",
 988                                        ren1_src, ren1_dst, branchName1,
 989                                        ren1_dst, branchName2);
 990                                 newPath = unique_path(ren1_dst, branchName2);
 991                                 output("Adding as %s instead", newPath);
 992                                 update_file(0, dst_other.sha1, dst_other.mode, newPath);
 993                         } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
 994                                 ren2 = item->util;
 995                                 cleanMerge = 0;
 996                                 ren2->processed = 1;
 997                                 output("CONFLICT (rename/rename): Rename %s->%s in %s. "
 998                                        "Rename %s->%s in %s",
 999                                        ren1_src, ren1_dst, branchName1,
1000                                        ren2->pair->one->path, ren2->pair->two->path, branchName2);
1001                                 conflict_rename_rename_2(ren1, branchName1, ren2, branchName2);
1002                         } else
1003                                 tryMerge = 1;
1004
1005                         if (tryMerge) {
1006                                 struct diff_filespec *o, *a, *b;
1007                                 struct merge_file_info mfi;
1008                                 src_other.path = (char *)ren1_src;
1009
1010                                 o = ren1->pair->one;
1011                                 if (renamesA == renames1) {
1012                                         a = ren1->pair->two;
1013                                         b = &src_other;
1014                                 } else {
1015                                         b = ren1->pair->two;
1016                                         a = &src_other;
1017                                 }
1018                                 mfi = merge_file(o, a, b,
1019                                                 branchNameA, branchNameB);
1020
1021                                 if (mfi.merge || !mfi.clean)
1022                                         output("Renaming %s => %s", ren1_src, ren1_dst);
1023                                 if (mfi.merge)
1024                                         output("Auto-merging %s", ren1_dst);
1025                                 if (!mfi.clean) {
1026                                         output("CONFLICT (rename/modify): Merge conflict in %s",
1027                                                ren1_dst);
1028                                         cleanMerge = 0;
1029
1030                                         if (!index_only)
1031                                                 update_stages(ren1_dst,
1032                                                                 o, a, b, 1);
1033                                 }
1034                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1035                         }
1036                 }
1037         }
1038         path_list_clear(&byDstA, 0);
1039         path_list_clear(&byDstB, 0);
1040
1041         if (cache_dirty)
1042                 flush_cache();
1043         return cleanMerge;
1044 }
1045
1046 static unsigned char *has_sha(const unsigned char *sha)
1047 {
1048         return memcmp(sha, null_sha1, 20) == 0 ? NULL: (unsigned char *)sha;
1049 }
1050
1051 /* Per entry merge function */
1052 static int process_entry(const char *path, struct stage_data *entry,
1053                          const char *branch1Name,
1054                          const char *branch2Name)
1055 {
1056         /*
1057         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1058         print_index_entry("\tpath: ", entry);
1059         */
1060         int cleanMerge = 1;
1061         unsigned char *oSha = has_sha(entry->stages[1].sha);
1062         unsigned char *aSha = has_sha(entry->stages[2].sha);
1063         unsigned char *bSha = has_sha(entry->stages[3].sha);
1064         unsigned oMode = entry->stages[1].mode;
1065         unsigned aMode = entry->stages[2].mode;
1066         unsigned bMode = entry->stages[3].mode;
1067
1068         if (oSha && (!aSha || !bSha)) {
1069                 /* Case A: Deleted in one */
1070                 if ((!aSha && !bSha) ||
1071                     (sha_eq(aSha, oSha) && !bSha) ||
1072                     (!aSha && sha_eq(bSha, oSha))) {
1073                         /* Deleted in both or deleted in one and
1074                          * unchanged in the other */
1075                         if (aSha)
1076                                 output("Removing %s", path);
1077                         remove_file(1, path);
1078                 } else {
1079                         /* Deleted in one and changed in the other */
1080                         cleanMerge = 0;
1081                         if (!aSha) {
1082                                 output("CONFLICT (delete/modify): %s deleted in %s "
1083                                        "and modified in %s. Version %s of %s left in tree.",
1084                                        path, branch1Name,
1085                                        branch2Name, branch2Name, path);
1086                                 update_file(0, bSha, bMode, path);
1087                         } else {
1088                                 output("CONFLICT (delete/modify): %s deleted in %s "
1089                                        "and modified in %s. Version %s of %s left in tree.",
1090                                        path, branch2Name,
1091                                        branch1Name, branch1Name, path);
1092                                 update_file(0, aSha, aMode, path);
1093                         }
1094                 }
1095
1096         } else if ((!oSha && aSha && !bSha) ||
1097                    (!oSha && !aSha && bSha)) {
1098                 /* Case B: Added in one. */
1099                 const char *addBranch;
1100                 const char *otherBranch;
1101                 unsigned mode;
1102                 const unsigned char *sha;
1103                 const char *conf;
1104
1105                 if (aSha) {
1106                         addBranch = branch1Name;
1107                         otherBranch = branch2Name;
1108                         mode = aMode;
1109                         sha = aSha;
1110                         conf = "file/directory";
1111                 } else {
1112                         addBranch = branch2Name;
1113                         otherBranch = branch1Name;
1114                         mode = bMode;
1115                         sha = bSha;
1116                         conf = "directory/file";
1117                 }
1118                 if (path_list_has_path(&currentDirectorySet, path)) {
1119                         const char *newPath = unique_path(path, addBranch);
1120                         cleanMerge = 0;
1121                         output("CONFLICT (%s): There is a directory with name %s in %s. "
1122                                "Adding %s as %s",
1123                                conf, path, otherBranch, path, newPath);
1124                         remove_file(0, path);
1125                         update_file(0, sha, mode, newPath);
1126                 } else {
1127                         output("Adding %s", path);
1128                         update_file(1, sha, mode, path);
1129                 }
1130         } else if (!oSha && aSha && bSha) {
1131                 /* Case C: Added in both (check for same permissions). */
1132                 if (sha_eq(aSha, bSha)) {
1133                         if (aMode != bMode) {
1134                                 cleanMerge = 0;
1135                                 output("CONFLICT: File %s added identically in both branches, "
1136                                        "but permissions conflict %06o->%06o",
1137                                        path, aMode, bMode);
1138                                 output("CONFLICT: adding with permission: %06o", aMode);
1139                                 update_file(0, aSha, aMode, path);
1140                         } else {
1141                                 /* This case is handled by git-read-tree */
1142                                 assert(0 && "This case must be handled by git-read-tree");
1143                         }
1144                 } else {
1145                         const char *newPath1, *newPath2;
1146                         cleanMerge = 0;
1147                         newPath1 = unique_path(path, branch1Name);
1148                         newPath2 = unique_path(path, branch2Name);
1149                         output("CONFLICT (add/add): File %s added non-identically "
1150                                "in both branches. Adding as %s and %s instead.",
1151                                path, newPath1, newPath2);
1152                         remove_file(0, path);
1153                         update_file(0, aSha, aMode, newPath1);
1154                         update_file(0, bSha, bMode, newPath2);
1155                 }
1156
1157         } else if (oSha && aSha && bSha) {
1158                 /* case D: Modified in both, but differently. */
1159                 struct merge_file_info mfi;
1160                 struct diff_filespec o, a, b;
1161
1162                 output("Auto-merging %s", path);
1163                 o.path = a.path = b.path = (char *)path;
1164                 memcpy(o.sha1, oSha, 20);
1165                 o.mode = oMode;
1166                 memcpy(a.sha1, aSha, 20);
1167                 a.mode = aMode;
1168                 memcpy(b.sha1, bSha, 20);
1169                 b.mode = bMode;
1170
1171                 mfi = merge_file(&o, &a, &b,
1172                                  branch1Name, branch2Name);
1173
1174                 if (mfi.clean)
1175                         update_file(1, mfi.sha, mfi.mode, path);
1176                 else {
1177                         cleanMerge = 0;
1178                         output("CONFLICT (content): Merge conflict in %s", path);
1179
1180                         if (index_only)
1181                                 update_file(0, mfi.sha, mfi.mode, path);
1182                         else
1183                                 update_file_flags(mfi.sha, mfi.mode, path,
1184                                               0 /* updateCache */, 1 /* updateWd */);
1185                 }
1186         } else
1187                 die("Fatal merge failure, shouldn't happen.");
1188
1189         if (cache_dirty)
1190                 flush_cache();
1191
1192         return cleanMerge;
1193 }
1194
1195 static int merge_trees(struct tree *head,
1196                        struct tree *merge,
1197                        struct tree *common,
1198                        const char *branch1Name,
1199                        const char *branch2Name,
1200                        struct tree **result)
1201 {
1202         int code, clean;
1203         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1204                 output("Already uptodate!");
1205                 *result = head;
1206                 return 1;
1207         }
1208
1209         code = git_merge_trees(index_only ? "-i": "-u", common, head, merge);
1210
1211         if (code != 0)
1212                 die("merging of trees %s and %s failed",
1213                     sha1_to_hex(head->object.sha1),
1214                     sha1_to_hex(merge->object.sha1));
1215
1216         *result = git_write_tree();
1217
1218         if (!*result) {
1219                 struct path_list *entries, *re_head, *re_merge;
1220                 int i;
1221                 path_list_clear(&currentFileSet, 1);
1222                 path_list_clear(&currentDirectorySet, 1);
1223                 get_files_dirs(head);
1224                 get_files_dirs(merge);
1225
1226                 entries = get_unmerged();
1227                 re_head  = get_renames(head, common, head, merge, entries);
1228                 re_merge = get_renames(merge, common, head, merge, entries);
1229                 clean = process_renames(re_head, re_merge,
1230                                 branch1Name, branch2Name);
1231                 for (i = 0; i < entries->nr; i++) {
1232                         const char *path = entries->items[i].path;
1233                         struct stage_data *e = entries->items[i].util;
1234                         if (e->processed)
1235                                 continue;
1236                         if (!process_entry(path, e, branch1Name, branch2Name))
1237                                 clean = 0;
1238                 }
1239
1240                 path_list_clear(re_merge, 0);
1241                 path_list_clear(re_head, 0);
1242                 path_list_clear(entries, 1);
1243
1244                 if (clean || index_only)
1245                         *result = git_write_tree();
1246                 else
1247                         *result = NULL;
1248         } else {
1249                 clean = 1;
1250                 printf("merging of trees %s and %s resulted in %s\n",
1251                        sha1_to_hex(head->object.sha1),
1252                        sha1_to_hex(merge->object.sha1),
1253                        sha1_to_hex((*result)->object.sha1));
1254         }
1255
1256         return clean;
1257 }
1258
1259 /*
1260  * Merge the commits h1 and h2, return the resulting virtual
1261  * commit object and a flag indicating the cleaness of the merge.
1262  */
1263 static
1264 int merge(struct commit *h1,
1265                           struct commit *h2,
1266                           const char *branch1Name,
1267                           const char *branch2Name,
1268                           int callDepth /* =0 */,
1269                           struct commit *ancestor /* =None */,
1270                           struct commit **result)
1271 {
1272         struct commit_list *ca = NULL, *iter;
1273         struct commit *mergedCA;
1274         struct tree *mrtree;
1275         int clean;
1276
1277         output("Merging:");
1278         output_commit_title(h1);
1279         output_commit_title(h2);
1280
1281         if (ancestor)
1282                 commit_list_insert(ancestor, &ca);
1283         else
1284                 ca = get_merge_bases(h1, h2, 1);
1285
1286         output("found %u common ancestor(s):", commit_list_count(ca));
1287         for (iter = ca; iter; iter = iter->next)
1288                 output_commit_title(iter->item);
1289
1290         mergedCA = pop_commit(&ca);
1291
1292         for (iter = ca; iter; iter = iter->next) {
1293                 output_indent = callDepth + 1;
1294                 /*
1295                  * When the merge fails, the result contains files
1296                  * with conflict markers. The cleanness flag is
1297                  * ignored, it was never acutally used, as result of
1298                  * merge_trees has always overwritten it: the commited
1299                  * "conflicts" were already resolved.
1300                  */
1301                 merge(mergedCA, iter->item,
1302                       "Temporary merge branch 1",
1303                       "Temporary merge branch 2",
1304                       callDepth + 1,
1305                       NULL,
1306                       &mergedCA);
1307                 output_indent = callDepth;
1308
1309                 if (!mergedCA)
1310                         die("merge returned no commit");
1311         }
1312
1313         if (callDepth == 0) {
1314                 setup_index(0 /* $GIT_DIR/index */);
1315                 index_only = 0;
1316         } else {
1317                 setup_index(1 /* temporary index */);
1318                 git_read_tree(h1->tree);
1319                 index_only = 1;
1320         }
1321
1322         clean = merge_trees(h1->tree, h2->tree, mergedCA->tree,
1323                             branch1Name, branch2Name, &mrtree);
1324
1325         if (!ancestor && (clean || index_only)) {
1326                 *result = make_virtual_commit(mrtree, "merged tree");
1327                 commit_list_insert(h1, &(*result)->parents);
1328                 commit_list_insert(h2, &(*result)->parents->next);
1329         } else
1330                 *result = NULL;
1331
1332         return clean;
1333 }
1334
1335 static struct commit *get_ref(const char *ref)
1336 {
1337         unsigned char sha1[20];
1338         struct object *object;
1339
1340         if (get_sha1(ref, sha1))
1341                 die("Could not resolve ref '%s'", ref);
1342         object = deref_tag(parse_object(sha1), ref, strlen(ref));
1343         if (object->type != OBJ_COMMIT)
1344                 return NULL;
1345         if (parse_commit((struct commit *)object))
1346                 die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1347         return (struct commit *)object;
1348 }
1349
1350 int main(int argc, char *argv[])
1351 {
1352         static const char *bases[2];
1353         static unsigned bases_count = 0;
1354         int i, clean;
1355         const char *branch1, *branch2;
1356         struct commit *result, *h1, *h2;
1357
1358         original_index_file = getenv("GIT_INDEX_FILE");
1359
1360         if (!original_index_file)
1361                 original_index_file = strdup(git_path("index"));
1362
1363         temporary_index_file = strdup(git_path("mrg-rcrsv-tmp-idx"));
1364
1365         if (argc < 4)
1366                 die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1367
1368         for (i = 1; i < argc; ++i) {
1369                 if (!strcmp(argv[i], "--"))
1370                         break;
1371                 if (bases_count < sizeof(bases)/sizeof(*bases))
1372                         bases[bases_count++] = argv[i];
1373         }
1374         if (argc - i != 3) /* "--" "<head>" "<remote>" */
1375                 die("Not handling anything other than two heads merge.");
1376
1377         branch1 = argv[++i];
1378         branch2 = argv[++i];
1379         printf("Merging %s with %s\n", branch1, branch2);
1380
1381         h1 = get_ref(branch1);
1382         h2 = get_ref(branch2);
1383
1384         if (bases_count == 1) {
1385                 struct commit *ancestor = get_ref(bases[0]);
1386                 clean = merge(h1, h2, branch1, branch2, 0, ancestor, &result);
1387         } else
1388                 clean = merge(h1, h2, branch1, branch2, 0, NULL, &result);
1389
1390         if (cache_dirty)
1391                 flush_cache();
1392
1393         return clean ? 0: 1;
1394 }
1395
1396 /*
1397 vim: sw=8 noet
1398 */