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 "cache.h"
   7 #include "cache-tree.h"
   8 #include "commit.h"
   9 #include "blob.h"
  10 #include "tree-walk.h"
  11 #include "diff.h"
  12 #include "diffcore.h"
  13 #include "run-command.h"
  14 #include "tag.h"
  15 #include "unpack-trees.h"
  16 #include "path-list.h"
  17 #include "xdiff-interface.h"
  18
  19 /*
  20  * A virtual commit has
  21  * - (const char *)commit->util set to the name, and
  22  * - *(int *)commit->object.sha1 set to the virtual id.
  23  */
  24
  25 static unsigned commit_list_count(const struct commit_list *l)
  26 {
  27         unsigned c = 0;
  28         for (; l; l = l->next )
  29                 c++;
  30         return c;
  31 }
  32
  33 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  34 {
  35         struct commit *commit = xcalloc(1, sizeof(struct commit));
  36         static unsigned virtual_id = 1;
  37         commit->tree = tree;
  38         commit->util = (void*)comment;
  39         *(int*)commit->object.sha1 = virtual_id++;
  40         /* avoid warnings */
  41         commit->object.parsed = 1;
  42         return commit;
  43 }
  44
  45 /*
  46  * Since we use get_tree_entry(), which does not put the read object into
  47  * the object pool, we cannot rely on a == b.
  48  */
  49 static int sha_eq(const unsigned char *a, const unsigned char *b)
  50 {
  51         if (!a && !b)
  52                 return 2;
  53         return a && b && hashcmp(a, b) == 0;
  54 }
  55
  56 /*
  57  * Since we want to write the index eventually, we cannot reuse the index
  58  * for these (temporary) data.
  59  */
  60 struct stage_data
  61 {
  62         struct
  63         {
  64                 unsigned mode;
  65                 unsigned char sha[20];
  66         } stages[4];
  67         unsigned processed:1;
  68 };
  69
  70 static struct path_list current_file_set = {NULL, 0, 0, 1};
  71 static struct path_list current_directory_set = {NULL, 0, 0, 1};
  72
  73 static int call_depth = 0;
  74 static int verbosity = 2;
  75
  76 static int show (int v)
  77 {
  78         return (!call_depth && verbosity >= v) || verbosity >= 5;
  79 }
  80
  81 static void output(int v, const char *fmt, ...)
  82 {
  83         va_list args;
  84         va_start(args, fmt);
  85         if (show(v)) {
  86                 int i;
  87                 for (i = call_depth; i--;)
  88                         fputs("  ", stdout);
  89                 vfprintf(stdout, fmt, args);
  90                 fputc('\n', stdout);
  91         }
  92         va_end(args);
  93 }
  94
  95 static void output_commit_title(struct commit *commit)
  96 {
  97         int i;
  98         for (i = call_depth; i--;)
  99                 fputs("  ", stdout);
 100         if (commit->util)
 101                 printf("virtual %s\n", (char *)commit->util);
 102         else {
 103                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 104                 if (parse_commit(commit) != 0)
 105                         printf("(bad commit)\n");
 106                 else {
 107                         const char *s;
 108                         int len;
 109                         for (s = commit->buffer; *s; s++)
 110                                 if (*s == '\n' && s[1] == '\n') {
 111                                         s += 2;
 112                                         break;
 113                                 }
 114                         for (len = 0; s[len] && '\n' != s[len]; len++)
 115                                 ; /* do nothing */
 116                         printf("%.*s\n", len, s);
 117                 }
 118         }
 119 }
 120
 121 static struct cache_entry *make_cache_entry(unsigned int mode,
 122                 const unsigned char *sha1, const char *path, int stage, int refresh)
 123 {
 124         int size, len;
 125         struct cache_entry *ce;
 126
 127         if (!verify_path(path))
 128                 return NULL;
 129
 130         len = strlen(path);
 131         size = cache_entry_size(len);
 132         ce = xcalloc(1, size);
 133
 134         hashcpy(ce->sha1, sha1);
 135         memcpy(ce->name, path, len);
 136         ce->ce_flags = create_ce_flags(len, stage);
 137         ce->ce_mode = create_ce_mode(mode);
 138
 139         if (refresh)
 140                 return refresh_cache_entry(ce, 0);
 141
 142         return ce;
 143 }
 144
 145 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 146                 const char *path, int stage, int refresh, int options)
 147 {
 148         struct cache_entry *ce;
 149         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 150         if (!ce)
 151                 return error("cache_addinfo failed: %s", strerror(cache_errno));
 152         return add_cache_entry(ce, options);
 153 }
 154
 155 /*
 156  * This is a global variable which is used in a number of places but
 157  * only written to in the 'merge' function.
 158  *
 159  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
 160  *                       don't update the working directory.
 161  *               0    => Leave unmerged entries in the cache and update
 162  *                       the working directory.
 163  */
 164 static int index_only = 0;
 165
 166 static int git_merge_trees(int index_only,
 167                            struct tree *common,
 168                            struct tree *head,
 169                            struct tree *merge)
 170 {
 171         int rc;
 172         struct object_list *trees = NULL;
 173         struct unpack_trees_options opts;
 174
 175         memset(&opts, 0, sizeof(opts));
 176         if (index_only)
 177                 opts.index_only = 1;
 178         else
 179                 opts.update = 1;
 180         opts.merge = 1;
 181         opts.head_idx = 2;
 182         opts.fn = threeway_merge;
 183
 184         object_list_append(&common->object, &trees);
 185         object_list_append(&head->object, &trees);
 186         object_list_append(&merge->object, &trees);
 187
 188         rc = unpack_trees(trees, &opts);
 189         cache_tree_free(&active_cache_tree);
 190         return rc;
 191 }
 192
 193 static int unmerged_index(void)
 194 {
 195         int i;
 196         for (i = 0; i < active_nr; i++) {
 197                 struct cache_entry *ce = active_cache[i];
 198                 if (ce_stage(ce))
 199                         return 1;
 200         }
 201         return 0;
 202 }
 203
 204 static struct tree *git_write_tree(void)
 205 {
 206         struct tree *result = NULL;
 207
 208         if (unmerged_index())
 209                 return NULL;
 210
 211         if (!active_cache_tree)
 212                 active_cache_tree = cache_tree();
 213
 214         if (!cache_tree_fully_valid(active_cache_tree) &&
 215             cache_tree_update(active_cache_tree,
 216                               active_cache, active_nr, 0, 0) < 0)
 217                 die("error building trees");
 218
 219         result = lookup_tree(active_cache_tree->sha1);
 220
 221         return result;
 222 }
 223
 224 static int save_files_dirs(const unsigned char *sha1,
 225                 const char *base, int baselen, const char *path,
 226                 unsigned int mode, int stage)
 227 {
 228         int len = strlen(path);
 229         char *newpath = xmalloc(baselen + len + 1);
 230         memcpy(newpath, base, baselen);
 231         memcpy(newpath + baselen, path, len);
 232         newpath[baselen + len] = '\0';
 233
 234         if (S_ISDIR(mode))
 235                 path_list_insert(newpath, &current_directory_set);
 236         else
 237                 path_list_insert(newpath, &current_file_set);
 238         free(newpath);
 239
 240         return READ_TREE_RECURSIVE;
 241 }
 242
 243 static int get_files_dirs(struct tree *tree)
 244 {
 245         int n;
 246         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
 247                 return 0;
 248         n = current_file_set.nr + current_directory_set.nr;
 249         return n;
 250 }
 251
 252 /*
 253  * Returns a index_entry instance which doesn't have to correspond to
 254  * a real cache entry in Git's index.
 255  */
 256 static struct stage_data *insert_stage_data(const char *path,
 257                 struct tree *o, struct tree *a, struct tree *b,
 258                 struct path_list *entries)
 259 {
 260         struct path_list_item *item;
 261         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 262         get_tree_entry(o->object.sha1, path,
 263                         e->stages[1].sha, &e->stages[1].mode);
 264         get_tree_entry(a->object.sha1, path,
 265                         e->stages[2].sha, &e->stages[2].mode);
 266         get_tree_entry(b->object.sha1, path,
 267                         e->stages[3].sha, &e->stages[3].mode);
 268         item = path_list_insert(path, entries);
 269         item->util = e;
 270         return e;
 271 }
 272
 273 /*
 274  * Create a dictionary mapping file names to stage_data objects. The
 275  * dictionary contains one entry for every path with a non-zero stage entry.
 276  */
 277 static struct path_list *get_unmerged(void)
 278 {
 279         struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
 280         int i;
 281
 282         unmerged->strdup_paths = 1;
 283
 284         for (i = 0; i < active_nr; i++) {
 285                 struct path_list_item *item;
 286                 struct stage_data *e;
 287                 struct cache_entry *ce = active_cache[i];
 288                 if (!ce_stage(ce))
 289                         continue;
 290
 291                 item = path_list_lookup(ce->name, unmerged);
 292                 if (!item) {
 293                         item = path_list_insert(ce->name, unmerged);
 294                         item->util = xcalloc(1, sizeof(struct stage_data));
 295                 }
 296                 e = item->util;
 297                 e->stages[ce_stage(ce)].mode = ntohl(ce->ce_mode);
 298                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 299         }
 300
 301         return unmerged;
 302 }
 303
 304 struct rename
 305 {
 306         struct diff_filepair *pair;
 307         struct stage_data *src_entry;
 308         struct stage_data *dst_entry;
 309         unsigned processed:1;
 310 };
 311
 312 /*
 313  * Get information of all renames which occured between 'o_tree' and
 314  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 315  * 'b_tree') to be able to associate the correct cache entries with
 316  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 317  */
 318 static struct path_list *get_renames(struct tree *tree,
 319                                         struct tree *o_tree,
 320                                         struct tree *a_tree,
 321                                         struct tree *b_tree,
 322                                         struct path_list *entries)
 323 {
 324         int i;
 325         struct path_list *renames;
 326         struct diff_options opts;
 327
 328         renames = xcalloc(1, sizeof(struct path_list));
 329         diff_setup(&opts);
 330         opts.recursive = 1;
 331         opts.detect_rename = DIFF_DETECT_RENAME;
 332         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 333         if (diff_setup_done(&opts) < 0)
 334                 die("diff setup failed");
 335         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 336         diffcore_std(&opts);
 337         for (i = 0; i < diff_queued_diff.nr; ++i) {
 338                 struct path_list_item *item;
 339                 struct rename *re;
 340                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 341                 if (pair->status != 'R') {
 342                         diff_free_filepair(pair);
 343                         continue;
 344                 }
 345                 re = xmalloc(sizeof(*re));
 346                 re->processed = 0;
 347                 re->pair = pair;
 348                 item = path_list_lookup(re->pair->one->path, entries);
 349                 if (!item)
 350                         re->src_entry = insert_stage_data(re->pair->one->path,
 351                                         o_tree, a_tree, b_tree, entries);
 352                 else
 353                         re->src_entry = item->util;
 354
 355                 item = path_list_lookup(re->pair->two->path, entries);
 356                 if (!item)
 357                         re->dst_entry = insert_stage_data(re->pair->two->path,
 358                                         o_tree, a_tree, b_tree, entries);
 359                 else
 360                         re->dst_entry = item->util;
 361                 item = path_list_insert(pair->one->path, renames);
 362                 item->util = re;
 363         }
 364         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 365         diff_queued_diff.nr = 0;
 366         diff_flush(&opts);
 367         return renames;
 368 }
 369
 370 static int update_stages(const char *path, struct diff_filespec *o,
 371                          struct diff_filespec *a, struct diff_filespec *b,
 372                          int clear)
 373 {
 374         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 375         if (clear)
 376                 if (remove_file_from_cache(path))
 377                         return -1;
 378         if (o)
 379                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 380                         return -1;
 381         if (a)
 382                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 383                         return -1;
 384         if (b)
 385                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 386                         return -1;
 387         return 0;
 388 }
 389
 390 static int remove_path(const char *name)
 391 {
 392         int ret, len;
 393         char *slash, *dirs;
 394
 395         ret = unlink(name);
 396         if (ret)
 397                 return ret;
 398         len = strlen(name);
 399         dirs = xmalloc(len+1);
 400         memcpy(dirs, name, len);
 401         dirs[len] = '\0';
 402         while ((slash = strrchr(name, '/'))) {
 403                 *slash = '\0';
 404                 len = slash - name;
 405                 if (rmdir(name) != 0)
 406                         break;
 407         }
 408         free(dirs);
 409         return ret;
 410 }
 411
 412 static int remove_file(int clean, const char *path, int no_wd)
 413 {
 414         int update_cache = index_only || clean;
 415         int update_working_directory = !index_only && !no_wd;
 416
 417         if (update_cache) {
 418                 if (remove_file_from_cache(path))
 419                         return -1;
 420         }
 421         if (update_working_directory) {
 422                 unlink(path);
 423                 if (errno != ENOENT || errno != EISDIR)
 424                         return -1;
 425                 remove_path(path);
 426         }
 427         return 0;
 428 }
 429
 430 static char *unique_path(const char *path, const char *branch)
 431 {
 432         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 433         int suffix = 0;
 434         struct stat st;
 435         char *p = newpath + strlen(path);
 436         strcpy(newpath, path);
 437         *(p++) = '~';
 438         strcpy(p, branch);
 439         for (; *p; ++p)
 440                 if ('/' == *p)
 441                         *p = '_';
 442         while (path_list_has_path(&current_file_set, newpath) ||
 443                path_list_has_path(&current_directory_set, newpath) ||
 444                lstat(newpath, &st) == 0)
 445                 sprintf(p, "_%d", suffix++);
 446
 447         path_list_insert(newpath, &current_file_set);
 448         return newpath;
 449 }
 450
 451 static int mkdir_p(const char *path, unsigned long mode)
 452 {
 453         /* path points to cache entries, so xstrdup before messing with it */
 454         char *buf = xstrdup(path);
 455         int result = safe_create_leading_directories(buf);
 456         free(buf);
 457         return result;
 458 }
 459
 460 static void flush_buffer(int fd, const char *buf, unsigned long size)
 461 {
 462         while (size > 0) {
 463                 long ret = write_in_full(fd, buf, size);
 464                 if (ret < 0) {
 465                         /* Ignore epipe */
 466                         if (errno == EPIPE)
 467                                 break;
 468                         die("merge-recursive: %s", strerror(errno));
 469                 } else if (!ret) {
 470                         die("merge-recursive: disk full?");
 471                 }
 472                 size -= ret;
 473                 buf += ret;
 474         }
 475 }
 476
 477 static void update_file_flags(const unsigned char *sha,
 478                               unsigned mode,
 479                               const char *path,
 480                               int update_cache,
 481                               int update_wd)
 482 {
 483         if (index_only)
 484                 update_wd = 0;
 485
 486         if (update_wd) {
 487                 char type[20];
 488                 void *buf;
 489                 unsigned long size;
 490
 491                 buf = read_sha1_file(sha, type, &size);
 492                 if (!buf)
 493                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 494                 if (strcmp(type, blob_type) != 0)
 495                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 496
 497                 if (S_ISREG(mode)) {
 498                         int fd;
 499                         if (mkdir_p(path, 0777))
 500                                 die("failed to create path %s: %s", path, strerror(errno));
 501                         unlink(path);
 502                         if (mode & 0100)
 503                                 mode = 0777;
 504                         else
 505                                 mode = 0666;
 506                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 507                         if (fd < 0)
 508                                 die("failed to open %s: %s", path, strerror(errno));
 509                         flush_buffer(fd, buf, size);
 510                         close(fd);
 511                 } else if (S_ISLNK(mode)) {
 512                         char *lnk = xmalloc(size + 1);
 513                         memcpy(lnk, buf, size);
 514                         lnk[size] = '\0';
 515                         mkdir_p(path, 0777);
 516                         unlink(lnk);
 517                         symlink(lnk, path);
 518                 } else
 519                         die("do not know what to do with %06o %s '%s'",
 520                             mode, sha1_to_hex(sha), path);
 521         }
 522         if (update_cache)
 523                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 524 }
 525
 526 static void update_file(int clean,
 527                         const unsigned char *sha,
 528                         unsigned mode,
 529                         const char *path)
 530 {
 531         update_file_flags(sha, mode, path, index_only || clean, !index_only);
 532 }
 533
 534 /* Low level file merging, update and removal */
 535
 536 struct merge_file_info
 537 {
 538         unsigned char sha[20];
 539         unsigned mode;
 540         unsigned clean:1,
 541                  merge:1;
 542 };
 543
 544 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 545 {
 546         unsigned long size;
 547         char type[20];
 548
 549         if (!hashcmp(sha1, null_sha1)) {
 550                 mm->ptr = xstrdup("");
 551                 mm->size = 0;
 552                 return;
 553         }
 554
 555         mm->ptr = read_sha1_file(sha1, type, &size);
 556         if (!mm->ptr || strcmp(type, blob_type))
 557                 die("unable to read blob object %s", sha1_to_hex(sha1));
 558         mm->size = size;
 559 }
 560
 561 static struct merge_file_info merge_file(struct diff_filespec *o,
 562                 struct diff_filespec *a, struct diff_filespec *b,
 563                 const char *branch1, const char *branch2)
 564 {
 565         struct merge_file_info result;
 566         result.merge = 0;
 567         result.clean = 1;
 568
 569         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 570                 result.clean = 0;
 571                 if (S_ISREG(a->mode)) {
 572                         result.mode = a->mode;
 573                         hashcpy(result.sha, a->sha1);
 574                 } else {
 575                         result.mode = b->mode;
 576                         hashcpy(result.sha, b->sha1);
 577                 }
 578         } else {
 579                 if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
 580                         result.merge = 1;
 581
 582                 result.mode = a->mode == o->mode ? b->mode: a->mode;
 583
 584                 if (sha_eq(a->sha1, o->sha1))
 585                         hashcpy(result.sha, b->sha1);
 586                 else if (sha_eq(b->sha1, o->sha1))
 587                         hashcpy(result.sha, a->sha1);
 588                 else if (S_ISREG(a->mode)) {
 589                         mmfile_t orig, src1, src2;
 590                         mmbuffer_t result_buf;
 591                         xpparam_t xpp;
 592                         char *name1, *name2;
 593                         int merge_status;
 594
 595                         name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 596                         name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 597
 598                         fill_mm(o->sha1, &orig);
 599                         fill_mm(a->sha1, &src1);
 600                         fill_mm(b->sha1, &src2);
 601
 602                         memset(&xpp, 0, sizeof(xpp));
 603                         merge_status = xdl_merge(&orig,
 604                                                  &src1, name1,
 605                                                  &src2, name2,
 606                                                  &xpp, XDL_MERGE_ZEALOUS,
 607                                                  &result_buf);
 608                         free(name1);
 609                         free(name2);
 610                         free(orig.ptr);
 611                         free(src1.ptr);
 612                         free(src2.ptr);
 613
 614                         if ((merge_status < 0) || !result_buf.ptr)
 615                                 die("Failed to execute internal merge");
 616
 617                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 618                                             blob_type, result.sha))
 619                                 die("Unable to add %s to database",
 620                                     a->path);
 621
 622                         free(result_buf.ptr);
 623                         result.clean = (merge_status == 0);
 624                 } else {
 625                         if (!(S_ISLNK(a->mode) || S_ISLNK(b->mode)))
 626                                 die("cannot merge modes?");
 627
 628                         hashcpy(result.sha, a->sha1);
 629
 630                         if (!sha_eq(a->sha1, b->sha1))
 631                                 result.clean = 0;
 632                 }
 633         }
 634
 635         return result;
 636 }
 637
 638 static void conflict_rename_rename(struct rename *ren1,
 639                                    const char *branch1,
 640                                    struct rename *ren2,
 641                                    const char *branch2)
 642 {
 643         char *del[2];
 644         int delp = 0;
 645         const char *ren1_dst = ren1->pair->two->path;
 646         const char *ren2_dst = ren2->pair->two->path;
 647         const char *dst_name1 = ren1_dst;
 648         const char *dst_name2 = ren2_dst;
 649         if (path_list_has_path(&current_directory_set, ren1_dst)) {
 650                 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
 651                 output(1, "%s is a directory in %s adding as %s instead",
 652                        ren1_dst, branch2, dst_name1);
 653                 remove_file(0, ren1_dst, 0);
 654         }
 655         if (path_list_has_path(&current_directory_set, ren2_dst)) {
 656                 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
 657                 output(1, "%s is a directory in %s adding as %s instead",
 658                        ren2_dst, branch1, dst_name2);
 659                 remove_file(0, ren2_dst, 0);
 660         }
 661         update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 662         update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 663         while (delp--)
 664                 free(del[delp]);
 665 }
 666
 667 static void conflict_rename_dir(struct rename *ren1,
 668                                 const char *branch1)
 669 {
 670         char *new_path = unique_path(ren1->pair->two->path, branch1);
 671         output(1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
 672         remove_file(0, ren1->pair->two->path, 0);
 673         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 674         free(new_path);
 675 }
 676
 677 static void conflict_rename_rename_2(struct rename *ren1,
 678                                      const char *branch1,
 679                                      struct rename *ren2,
 680                                      const char *branch2)
 681 {
 682         char *new_path1 = unique_path(ren1->pair->two->path, branch1);
 683         char *new_path2 = unique_path(ren2->pair->two->path, branch2);
 684         output(1, "Renaming %s to %s and %s to %s instead",
 685                ren1->pair->one->path, new_path1,
 686                ren2->pair->one->path, new_path2);
 687         remove_file(0, ren1->pair->two->path, 0);
 688         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 689         update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 690         free(new_path2);
 691         free(new_path1);
 692 }
 693
 694 static int process_renames(struct path_list *a_renames,
 695                            struct path_list *b_renames,
 696                            const char *a_branch,
 697                            const char *b_branch)
 698 {
 699         int clean_merge = 1, i, j;
 700         struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 701         const struct rename *sre;
 702
 703         for (i = 0; i < a_renames->nr; i++) {
 704                 sre = a_renames->items[i].util;
 705                 path_list_insert(sre->pair->two->path, &a_by_dst)->util
 706                         = sre->dst_entry;
 707         }
 708         for (i = 0; i < b_renames->nr; i++) {
 709                 sre = b_renames->items[i].util;
 710                 path_list_insert(sre->pair->two->path, &b_by_dst)->util
 711                         = sre->dst_entry;
 712         }
 713
 714         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 715                 int compare;
 716                 char *src;
 717                 struct path_list *renames1, *renames2, *renames2Dst;
 718                 struct rename *ren1 = NULL, *ren2 = NULL;
 719                 const char *branch1, *branch2;
 720                 const char *ren1_src, *ren1_dst;
 721
 722                 if (i >= a_renames->nr) {
 723                         compare = 1;
 724                         ren2 = b_renames->items[j++].util;
 725                 } else if (j >= b_renames->nr) {
 726                         compare = -1;
 727                         ren1 = a_renames->items[i++].util;
 728                 } else {
 729                         compare = strcmp(a_renames->items[i].path,
 730                                         b_renames->items[j].path);
 731                         if (compare <= 0)
 732                                 ren1 = a_renames->items[i++].util;
 733                         if (compare >= 0)
 734                                 ren2 = b_renames->items[j++].util;
 735                 }
 736
 737                 /* TODO: refactor, so that 1/2 are not needed */
 738                 if (ren1) {
 739                         renames1 = a_renames;
 740                         renames2 = b_renames;
 741                         renames2Dst = &b_by_dst;
 742                         branch1 = a_branch;
 743                         branch2 = b_branch;
 744                 } else {
 745                         struct rename *tmp;
 746                         renames1 = b_renames;
 747                         renames2 = a_renames;
 748                         renames2Dst = &a_by_dst;
 749                         branch1 = b_branch;
 750                         branch2 = a_branch;
 751                         tmp = ren2;
 752                         ren2 = ren1;
 753                         ren1 = tmp;
 754                 }
 755                 src = ren1->pair->one->path;
 756
 757                 ren1->dst_entry->processed = 1;
 758                 ren1->src_entry->processed = 1;
 759
 760                 if (ren1->processed)
 761                         continue;
 762                 ren1->processed = 1;
 763
 764                 ren1_src = ren1->pair->one->path;
 765                 ren1_dst = ren1->pair->two->path;
 766
 767                 if (ren2) {
 768                         const char *ren2_src = ren2->pair->one->path;
 769                         const char *ren2_dst = ren2->pair->two->path;
 770                         /* Renamed in 1 and renamed in 2 */
 771                         if (strcmp(ren1_src, ren2_src) != 0)
 772                                 die("ren1.src != ren2.src");
 773                         ren2->dst_entry->processed = 1;
 774                         ren2->processed = 1;
 775                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 776                                 clean_merge = 0;
 777                                 output(1, "CONFLICT (rename/rename): "
 778                                        "Rename %s->%s in branch %s "
 779                                        "rename %s->%s in %s",
 780                                        src, ren1_dst, branch1,
 781                                        src, ren2_dst, branch2);
 782                                 conflict_rename_rename(ren1, branch1, ren2, branch2);
 783                         } else {
 784                                 struct merge_file_info mfi;
 785                                 remove_file(1, ren1_src, 1);
 786                                 mfi = merge_file(ren1->pair->one,
 787                                                  ren1->pair->two,
 788                                                  ren2->pair->two,
 789                                                  branch1,
 790                                                  branch2);
 791                                 if (mfi.merge || !mfi.clean)
 792                                         output(1, "Renaming %s->%s", src, ren1_dst);
 793
 794                                 if (mfi.merge)
 795                                         output(2, "Auto-merging %s", ren1_dst);
 796
 797                                 if (!mfi.clean) {
 798                                         output(1, "CONFLICT (content): merge conflict in %s",
 799                                                ren1_dst);
 800                                         clean_merge = 0;
 801
 802                                         if (!index_only)
 803                                                 update_stages(ren1_dst,
 804                                                               ren1->pair->one,
 805                                                               ren1->pair->two,
 806                                                               ren2->pair->two,
 807                                                               1 /* clear */);
 808                                 }
 809                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 810                         }
 811                 } else {
 812                         /* Renamed in 1, maybe changed in 2 */
 813                         struct path_list_item *item;
 814                         /* we only use sha1 and mode of these */
 815                         struct diff_filespec src_other, dst_other;
 816                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 817
 818                         remove_file(1, ren1_src, index_only);
 819
 820                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 821                         src_other.mode = ren1->src_entry->stages[stage].mode;
 822                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 823                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 824
 825                         try_merge = 0;
 826
 827                         if (path_list_has_path(&current_directory_set, ren1_dst)) {
 828                                 clean_merge = 0;
 829                                 output(1, "CONFLICT (rename/directory): Rename %s->%s in %s "
 830                                        " directory %s added in %s",
 831                                        ren1_src, ren1_dst, branch1,
 832                                        ren1_dst, branch2);
 833                                 conflict_rename_dir(ren1, branch1);
 834                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 835                                 clean_merge = 0;
 836                                 output(1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 837                                        "and deleted in %s",
 838                                        ren1_src, ren1_dst, branch1,
 839                                        branch2);
 840                                 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 841                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 842                                 const char *new_path;
 843                                 clean_merge = 0;
 844                                 try_merge = 1;
 845                                 output(1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 846                                        "%s added in %s",
 847                                        ren1_src, ren1_dst, branch1,
 848                                        ren1_dst, branch2);
 849                                 new_path = unique_path(ren1_dst, branch2);
 850                                 output(1, "Adding as %s instead", new_path);
 851                                 update_file(0, dst_other.sha1, dst_other.mode, new_path);
 852                         } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
 853                                 ren2 = item->util;
 854                                 clean_merge = 0;
 855                                 ren2->processed = 1;
 856                                 output(1, "CONFLICT (rename/rename): Rename %s->%s in %s. "
 857                                        "Rename %s->%s in %s",
 858                                        ren1_src, ren1_dst, branch1,
 859                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
 860                                 conflict_rename_rename_2(ren1, branch1, ren2, branch2);
 861                         } else
 862                                 try_merge = 1;
 863
 864                         if (try_merge) {
 865                                 struct diff_filespec *o, *a, *b;
 866                                 struct merge_file_info mfi;
 867                                 src_other.path = (char *)ren1_src;
 868
 869                                 o = ren1->pair->one;
 870                                 if (a_renames == renames1) {
 871                                         a = ren1->pair->two;
 872                                         b = &src_other;
 873                                 } else {
 874                                         b = ren1->pair->two;
 875                                         a = &src_other;
 876                                 }
 877                                 mfi = merge_file(o, a, b,
 878                                                 a_branch, b_branch);
 879
 880                                 if (mfi.merge || !mfi.clean)
 881                                         output(1, "Renaming %s => %s", ren1_src, ren1_dst);
 882                                 if (mfi.merge)
 883                                         output(2, "Auto-merging %s", ren1_dst);
 884                                 if (!mfi.clean) {
 885                                         output(1, "CONFLICT (rename/modify): Merge conflict in %s",
 886                                                ren1_dst);
 887                                         clean_merge = 0;
 888
 889                                         if (!index_only)
 890                                                 update_stages(ren1_dst,
 891                                                                 o, a, b, 1);
 892                                 }
 893                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 894                         }
 895                 }
 896         }
 897         path_list_clear(&a_by_dst, 0);
 898         path_list_clear(&b_by_dst, 0);
 899
 900         return clean_merge;
 901 }
 902
 903 static unsigned char *has_sha(const unsigned char *sha)
 904 {
 905         return is_null_sha1(sha) ? NULL: (unsigned char *)sha;
 906 }
 907
 908 /* Per entry merge function */
 909 static int process_entry(const char *path, struct stage_data *entry,
 910                          const char *branch1,
 911                          const char *branch2)
 912 {
 913         /*
 914         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
 915         print_index_entry("\tpath: ", entry);
 916         */
 917         int clean_merge = 1;
 918         unsigned char *o_sha = has_sha(entry->stages[1].sha);
 919         unsigned char *a_sha = has_sha(entry->stages[2].sha);
 920         unsigned char *b_sha = has_sha(entry->stages[3].sha);
 921         unsigned o_mode = entry->stages[1].mode;
 922         unsigned a_mode = entry->stages[2].mode;
 923         unsigned b_mode = entry->stages[3].mode;
 924
 925         if (o_sha && (!a_sha || !b_sha)) {
 926                 /* Case A: Deleted in one */
 927                 if ((!a_sha && !b_sha) ||
 928                     (sha_eq(a_sha, o_sha) && !b_sha) ||
 929                     (!a_sha && sha_eq(b_sha, o_sha))) {
 930                         /* Deleted in both or deleted in one and
 931                          * unchanged in the other */
 932                         if (a_sha)
 933                                 output(2, "Removing %s", path);
 934                         /* do not touch working file if it did not exist */
 935                         remove_file(1, path, !a_sha);
 936                 } else {
 937                         /* Deleted in one and changed in the other */
 938                         clean_merge = 0;
 939                         if (!a_sha) {
 940                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
 941                                        "and modified in %s. Version %s of %s left in tree.",
 942                                        path, branch1,
 943                                        branch2, branch2, path);
 944                                 update_file(0, b_sha, b_mode, path);
 945                         } else {
 946                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
 947                                        "and modified in %s. Version %s of %s left in tree.",
 948                                        path, branch2,
 949                                        branch1, branch1, path);
 950                                 update_file(0, a_sha, a_mode, path);
 951                         }
 952                 }
 953
 954         } else if ((!o_sha && a_sha && !b_sha) ||
 955                    (!o_sha && !a_sha && b_sha)) {
 956                 /* Case B: Added in one. */
 957                 const char *add_branch;
 958                 const char *other_branch;
 959                 unsigned mode;
 960                 const unsigned char *sha;
 961                 const char *conf;
 962
 963                 if (a_sha) {
 964                         add_branch = branch1;
 965                         other_branch = branch2;
 966                         mode = a_mode;
 967                         sha = a_sha;
 968                         conf = "file/directory";
 969                 } else {
 970                         add_branch = branch2;
 971                         other_branch = branch1;
 972                         mode = b_mode;
 973                         sha = b_sha;
 974                         conf = "directory/file";
 975                 }
 976                 if (path_list_has_path(&current_directory_set, path)) {
 977                         const char *new_path = unique_path(path, add_branch);
 978                         clean_merge = 0;
 979                         output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
 980                                "Adding %s as %s",
 981                                conf, path, other_branch, path, new_path);
 982                         remove_file(0, path, 0);
 983                         update_file(0, sha, mode, new_path);
 984                 } else {
 985                         output(2, "Adding %s", path);
 986                         update_file(1, sha, mode, path);
 987                 }
 988         } else if (a_sha && b_sha) {
 989                 /* Case C: Added in both (check for same permissions) and */
 990                 /* case D: Modified in both, but differently. */
 991                 const char *reason = "content";
 992                 struct merge_file_info mfi;
 993                 struct diff_filespec o, a, b;
 994
 995                 if (!o_sha) {
 996                         reason = "add/add";
 997                         o_sha = (unsigned char *)null_sha1;
 998                 }
 999                 output(2, "Auto-merging %s", path);
1000                 o.path = a.path = b.path = (char *)path;
1001                 hashcpy(o.sha1, o_sha);
1002                 o.mode = o_mode;
1003                 hashcpy(a.sha1, a_sha);
1004                 a.mode = a_mode;
1005                 hashcpy(b.sha1, b_sha);
1006                 b.mode = b_mode;
1007
1008                 mfi = merge_file(&o, &a, &b,
1009                                  branch1, branch2);
1010
1011                 if (mfi.clean)
1012                         update_file(1, mfi.sha, mfi.mode, path);
1013                 else {
1014                         clean_merge = 0;
1015                         output(1, "CONFLICT (%s): Merge conflict in %s",
1016                                         reason, path);
1017
1018                         if (index_only)
1019                                 update_file(0, mfi.sha, mfi.mode, path);
1020                         else
1021                                 update_file_flags(mfi.sha, mfi.mode, path,
1022                                               0 /* update_cache */, 1 /* update_working_directory */);
1023                 }
1024         } else
1025                 die("Fatal merge failure, shouldn't happen.");
1026
1027         return clean_merge;
1028 }
1029
1030 static int merge_trees(struct tree *head,
1031                        struct tree *merge,
1032                        struct tree *common,
1033                        const char *branch1,
1034                        const char *branch2,
1035                        struct tree **result)
1036 {
1037         int code, clean;
1038         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1039                 output(0, "Already uptodate!");
1040                 *result = head;
1041                 return 1;
1042         }
1043
1044         code = git_merge_trees(index_only, common, head, merge);
1045
1046         if (code != 0)
1047                 die("merging of trees %s and %s failed",
1048                     sha1_to_hex(head->object.sha1),
1049                     sha1_to_hex(merge->object.sha1));
1050
1051         if (unmerged_index()) {
1052                 struct path_list *entries, *re_head, *re_merge;
1053                 int i;
1054                 path_list_clear(&current_file_set, 1);
1055                 path_list_clear(&current_directory_set, 1);
1056                 get_files_dirs(head);
1057                 get_files_dirs(merge);
1058
1059                 entries = get_unmerged();
1060                 re_head  = get_renames(head, common, head, merge, entries);
1061                 re_merge = get_renames(merge, common, head, merge, entries);
1062                 clean = process_renames(re_head, re_merge,
1063                                 branch1, branch2);
1064                 for (i = 0; i < entries->nr; i++) {
1065                         const char *path = entries->items[i].path;
1066                         struct stage_data *e = entries->items[i].util;
1067                         if (e->processed)
1068                                 continue;
1069                         if (!process_entry(path, e, branch1, branch2))
1070                                 clean = 0;
1071                 }
1072
1073                 path_list_clear(re_merge, 0);
1074                 path_list_clear(re_head, 0);
1075                 path_list_clear(entries, 1);
1076
1077         }
1078         else
1079                 clean = 1;
1080
1081         if (index_only)
1082                 *result = git_write_tree();
1083
1084         return clean;
1085 }
1086
1087 static struct commit_list *reverse_commit_list(struct commit_list *list)
1088 {
1089         struct commit_list *next = NULL, *current, *backup;
1090         for (current = list; current; current = backup) {
1091                 backup = current->next;
1092                 current->next = next;
1093                 next = current;
1094         }
1095         return next;
1096 }
1097
1098 /*
1099  * Merge the commits h1 and h2, return the resulting virtual
1100  * commit object and a flag indicating the cleaness of the merge.
1101  */
1102 static int merge(struct commit *h1,
1103                  struct commit *h2,
1104                  const char *branch1,
1105                  const char *branch2,
1106                  struct commit_list *ca,
1107                  struct commit **result)
1108 {
1109         struct commit_list *iter;
1110         struct commit *merged_common_ancestors;
1111         struct tree *mrtree;
1112         int clean;
1113
1114         if (show(4)) {
1115                 output(4, "Merging:");
1116                 output_commit_title(h1);
1117                 output_commit_title(h2);
1118         }
1119
1120         if (!ca) {
1121                 ca = get_merge_bases(h1, h2, 1);
1122                 ca = reverse_commit_list(ca);
1123         }
1124
1125         if (show(5)) {
1126                 output(5, "found %u common ancestor(s):", commit_list_count(ca));
1127                 for (iter = ca; iter; iter = iter->next)
1128                         output_commit_title(iter->item);
1129         }
1130
1131         merged_common_ancestors = pop_commit(&ca);
1132         if (merged_common_ancestors == NULL) {
1133                 /* if there is no common ancestor, make an empty tree */
1134                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1135
1136                 tree->object.parsed = 1;
1137                 tree->object.type = OBJ_TREE;
1138                 write_sha1_file(NULL, 0, tree_type, tree->object.sha1);
1139                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1140         }
1141
1142         for (iter = ca; iter; iter = iter->next) {
1143                 call_depth++;
1144                 /*
1145                  * When the merge fails, the result contains files
1146                  * with conflict markers. The cleanness flag is
1147                  * ignored, it was never acutally used, as result of
1148                  * merge_trees has always overwritten it: the commited
1149                  * "conflicts" were already resolved.
1150                  */
1151                 discard_cache();
1152                 merge(merged_common_ancestors, iter->item,
1153                       "Temporary merge branch 1",
1154                       "Temporary merge branch 2",
1155                       NULL,
1156                       &merged_common_ancestors);
1157                 call_depth--;
1158
1159                 if (!merged_common_ancestors)
1160                         die("merge returned no commit");
1161         }
1162
1163         discard_cache();
1164         if (!call_depth) {
1165                 read_cache();
1166                 index_only = 0;
1167         } else
1168                 index_only = 1;
1169
1170         clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1171                             branch1, branch2, &mrtree);
1172
1173         if (index_only) {
1174                 *result = make_virtual_commit(mrtree, "merged tree");
1175                 commit_list_insert(h1, &(*result)->parents);
1176                 commit_list_insert(h2, &(*result)->parents->next);
1177         }
1178         return clean;
1179 }
1180
1181 static const char *better_branch_name(const char *branch)
1182 {
1183         static char githead_env[8 + 40 + 1];
1184         char *name;
1185
1186         if (strlen(branch) != 40)
1187                 return branch;
1188         sprintf(githead_env, "GITHEAD_%s", branch);
1189         name = getenv(githead_env);
1190         return name ? name : branch;
1191 }
1192
1193 static struct commit *get_ref(const char *ref)
1194 {
1195         unsigned char sha1[20];
1196         struct object *object;
1197
1198         if (get_sha1(ref, sha1))
1199                 die("Could not resolve ref '%s'", ref);
1200         object = deref_tag(parse_object(sha1), ref, strlen(ref));
1201         if (object->type == OBJ_TREE)
1202                 return make_virtual_commit((struct tree*)object,
1203                         better_branch_name(ref));
1204         if (object->type != OBJ_COMMIT)
1205                 return NULL;
1206         if (parse_commit((struct commit *)object))
1207                 die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1208         return (struct commit *)object;
1209 }
1210
1211 static int merge_config(const char *var, const char *value)
1212 {
1213         if (!strcasecmp(var, "merge.verbosity")) {
1214                 verbosity = git_config_int(var, value);
1215                 return 0;
1216         }
1217         return git_default_config(var, value);
1218 }
1219
1220 int main(int argc, char *argv[])
1221 {
1222         static const char *bases[20];
1223         static unsigned bases_count = 0;
1224         int i, clean;
1225         const char *branch1, *branch2;
1226         struct commit *result, *h1, *h2;
1227         struct commit_list *ca = NULL;
1228         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1229         int index_fd;
1230
1231         git_config(merge_config);
1232         if (getenv("GIT_MERGE_VERBOSITY"))
1233                 verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1234
1235         if (argc < 4)
1236                 die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1237
1238         for (i = 1; i < argc; ++i) {
1239                 if (!strcmp(argv[i], "--"))
1240                         break;
1241                 if (bases_count < sizeof(bases)/sizeof(*bases))
1242                         bases[bases_count++] = argv[i];
1243         }
1244         if (argc - i != 3) /* "--" "<head>" "<remote>" */
1245                 die("Not handling anything other than two heads merge.");
1246
1247         branch1 = argv[++i];
1248         branch2 = argv[++i];
1249
1250         h1 = get_ref(branch1);
1251         h2 = get_ref(branch2);
1252
1253         branch1 = better_branch_name(branch1);
1254         branch2 = better_branch_name(branch2);
1255         if (show(3))
1256                 printf("Merging %s with %s\n", branch1, branch2);
1257
1258         index_fd = hold_lock_file_for_update(lock, get_index_file(), 1);
1259
1260         for (i = 0; i < bases_count; i++) {
1261                 struct commit *ancestor = get_ref(bases[i]);
1262                 ca = commit_list_insert(ancestor, &ca);
1263         }
1264         clean = merge(h1, h2, branch1, branch2, ca, &result);
1265
1266         if (active_cache_changed &&
1267             (write_cache(index_fd, active_cache, active_nr) ||
1268              close(index_fd) || commit_lock_file(lock)))
1269                         die ("unable to write %s", get_index_file());
1270
1271         return clean ? 0: 1;
1272 }