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 output_indent = 0;
  74
  75 static void output(const char *fmt, ...)
  76 {
  77         va_list args;
  78         int i;
  79         for (i = output_indent; i--;)
  80                 fputs("  ", stdout);
  81         va_start(args, fmt);
  82         vfprintf(stdout, fmt, args);
  83         va_end(args);
  84         fputc('\n', stdout);
  85 }
  86
  87 static void output_commit_title(struct commit *commit)
  88 {
  89         int i;
  90         for (i = output_indent; i--;)
  91                 fputs("  ", stdout);
  92         if (commit->util)
  93                 printf("virtual %s\n", (char *)commit->util);
  94         else {
  95                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
  96                 if (parse_commit(commit) != 0)
  97                         printf("(bad commit)\n");
  98                 else {
  99                         const char *s;
 100                         int len;
 101                         for (s = commit->buffer; *s; s++)
 102                                 if (*s == '\n' && s[1] == '\n') {
 103                                         s += 2;
 104                                         break;
 105                                 }
 106                         for (len = 0; s[len] && '\n' != s[len]; len++)
 107                                 ; /* do nothing */
 108                         printf("%.*s\n", len, s);
 109                 }
 110         }
 111 }
 112
 113 static const char *current_index_file = NULL;
 114 static const char *original_index_file;
 115 static const char *temporary_index_file;
 116 static int cache_dirty = 0;
 117
 118 static int flush_cache(void)
 119 {
 120         /* flush temporary index */
 121         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 122         int fd = hold_lock_file_for_update(lock, current_index_file, 1);
 123         if (write_cache(fd, active_cache, active_nr) ||
 124                         close(fd) || commit_lock_file(lock))
 125                 die ("unable to write %s", current_index_file);
 126         discard_cache();
 127         cache_dirty = 0;
 128         return 0;
 129 }
 130
 131 static void setup_index(int temp)
 132 {
 133         current_index_file = temp ? temporary_index_file: original_index_file;
 134         if (cache_dirty) {
 135                 discard_cache();
 136                 cache_dirty = 0;
 137         }
 138         unlink(temporary_index_file);
 139         discard_cache();
 140 }
 141
 142 static struct cache_entry *make_cache_entry(unsigned int mode,
 143                 const unsigned char *sha1, const char *path, int stage, int refresh)
 144 {
 145         int size, len;
 146         struct cache_entry *ce;
 147
 148         if (!verify_path(path))
 149                 return NULL;
 150
 151         len = strlen(path);
 152         size = cache_entry_size(len);
 153         ce = xcalloc(1, size);
 154
 155         hashcpy(ce->sha1, sha1);
 156         memcpy(ce->name, path, len);
 157         ce->ce_flags = create_ce_flags(len, stage);
 158         ce->ce_mode = create_ce_mode(mode);
 159
 160         if (refresh)
 161                 return refresh_cache_entry(ce, 0);
 162
 163         return ce;
 164 }
 165
 166 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 167                 const char *path, int stage, int refresh, int options)
 168 {
 169         struct cache_entry *ce;
 170         if (!cache_dirty)
 171                 read_cache_from(current_index_file);
 172         cache_dirty++;
 173         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 174         if (!ce)
 175                 return error("cache_addinfo failed: %s", strerror(cache_errno));
 176         return add_cache_entry(ce, options);
 177 }
 178
 179 /*
 180  * This is a global variable which is used in a number of places but
 181  * only written to in the 'merge' function.
 182  *
 183  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
 184  *                       don't update the working directory.
 185  *               0    => Leave unmerged entries in the cache and update
 186  *                       the working directory.
 187  */
 188 static int index_only = 0;
 189
 190 static int git_read_tree(struct tree *tree)
 191 {
 192         int rc;
 193         struct object_list *trees = NULL;
 194         struct unpack_trees_options opts;
 195
 196         if (cache_dirty)
 197                 die("read-tree with dirty cache");
 198
 199         memset(&opts, 0, sizeof(opts));
 200         object_list_append(&tree->object, &trees);
 201         rc = unpack_trees(trees, &opts);
 202         cache_tree_free(&active_cache_tree);
 203
 204         if (rc == 0)
 205                 cache_dirty = 1;
 206
 207         return rc;
 208 }
 209
 210 static int git_merge_trees(int index_only,
 211                            struct tree *common,
 212                            struct tree *head,
 213                            struct tree *merge)
 214 {
 215         int rc;
 216         struct object_list *trees = NULL;
 217         struct unpack_trees_options opts;
 218
 219         if (!cache_dirty) {
 220                 read_cache_from(current_index_file);
 221                 cache_dirty = 1;
 222         }
 223
 224         memset(&opts, 0, sizeof(opts));
 225         if (index_only)
 226                 opts.index_only = 1;
 227         else
 228                 opts.update = 1;
 229         opts.merge = 1;
 230         opts.head_idx = 2;
 231         opts.fn = threeway_merge;
 232
 233         object_list_append(&common->object, &trees);
 234         object_list_append(&head->object, &trees);
 235         object_list_append(&merge->object, &trees);
 236
 237         rc = unpack_trees(trees, &opts);
 238         cache_tree_free(&active_cache_tree);
 239
 240         cache_dirty = 1;
 241
 242         return rc;
 243 }
 244
 245 static struct tree *git_write_tree(void)
 246 {
 247         struct tree *result = NULL;
 248
 249         if (cache_dirty) {
 250                 unsigned i;
 251                 for (i = 0; i < active_nr; i++) {
 252                         struct cache_entry *ce = active_cache[i];
 253                         if (ce_stage(ce))
 254                                 return NULL;
 255                 }
 256         } else
 257                 read_cache_from(current_index_file);
 258
 259         if (!active_cache_tree)
 260                 active_cache_tree = cache_tree();
 261
 262         if (!cache_tree_fully_valid(active_cache_tree) &&
 263                         cache_tree_update(active_cache_tree,
 264                                 active_cache, active_nr, 0, 0) < 0)
 265                 die("error building trees");
 266
 267         result = lookup_tree(active_cache_tree->sha1);
 268
 269         flush_cache();
 270         cache_dirty = 0;
 271
 272         return result;
 273 }
 274
 275 static int save_files_dirs(const unsigned char *sha1,
 276                 const char *base, int baselen, const char *path,
 277                 unsigned int mode, int stage)
 278 {
 279         int len = strlen(path);
 280         char *newpath = xmalloc(baselen + len + 1);
 281         memcpy(newpath, base, baselen);
 282         memcpy(newpath + baselen, path, len);
 283         newpath[baselen + len] = '\0';
 284
 285         if (S_ISDIR(mode))
 286                 path_list_insert(newpath, &current_directory_set);
 287         else
 288                 path_list_insert(newpath, &current_file_set);
 289         free(newpath);
 290
 291         return READ_TREE_RECURSIVE;
 292 }
 293
 294 static int get_files_dirs(struct tree *tree)
 295 {
 296         int n;
 297         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
 298                 return 0;
 299         n = current_file_set.nr + current_directory_set.nr;
 300         return n;
 301 }
 302
 303 /*
 304  * Returns a index_entry instance which doesn't have to correspond to
 305  * a real cache entry in Git's index.
 306  */
 307 static struct stage_data *insert_stage_data(const char *path,
 308                 struct tree *o, struct tree *a, struct tree *b,
 309                 struct path_list *entries)
 310 {
 311         struct path_list_item *item;
 312         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 313         get_tree_entry(o->object.sha1, path,
 314                         e->stages[1].sha, &e->stages[1].mode);
 315         get_tree_entry(a->object.sha1, path,
 316                         e->stages[2].sha, &e->stages[2].mode);
 317         get_tree_entry(b->object.sha1, path,
 318                         e->stages[3].sha, &e->stages[3].mode);
 319         item = path_list_insert(path, entries);
 320         item->util = e;
 321         return e;
 322 }
 323
 324 /*
 325  * Create a dictionary mapping file names to stage_data objects. The
 326  * dictionary contains one entry for every path with a non-zero stage entry.
 327  */
 328 static struct path_list *get_unmerged(void)
 329 {
 330         struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
 331         int i;
 332
 333         unmerged->strdup_paths = 1;
 334         if (!cache_dirty) {
 335                 read_cache_from(current_index_file);
 336                 cache_dirty++;
 337         }
 338         for (i = 0; i < active_nr; i++) {
 339                 struct path_list_item *item;
 340                 struct stage_data *e;
 341                 struct cache_entry *ce = active_cache[i];
 342                 if (!ce_stage(ce))
 343                         continue;
 344
 345                 item = path_list_lookup(ce->name, unmerged);
 346                 if (!item) {
 347                         item = path_list_insert(ce->name, unmerged);
 348                         item->util = xcalloc(1, sizeof(struct stage_data));
 349                 }
 350                 e = item->util;
 351                 e->stages[ce_stage(ce)].mode = ntohl(ce->ce_mode);
 352                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 353         }
 354
 355         return unmerged;
 356 }
 357
 358 struct rename
 359 {
 360         struct diff_filepair *pair;
 361         struct stage_data *src_entry;
 362         struct stage_data *dst_entry;
 363         unsigned processed:1;
 364 };
 365
 366 /*
 367  * Get information of all renames which occured between 'o_tree' and
 368  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 369  * 'b_tree') to be able to associate the correct cache entries with
 370  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 371  */
 372 static struct path_list *get_renames(struct tree *tree,
 373                                         struct tree *o_tree,
 374                                         struct tree *a_tree,
 375                                         struct tree *b_tree,
 376                                         struct path_list *entries)
 377 {
 378         int i;
 379         struct path_list *renames;
 380         struct diff_options opts;
 381
 382         renames = xcalloc(1, sizeof(struct path_list));
 383         diff_setup(&opts);
 384         opts.recursive = 1;
 385         opts.detect_rename = DIFF_DETECT_RENAME;
 386         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 387         if (diff_setup_done(&opts) < 0)
 388                 die("diff setup failed");
 389         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 390         diffcore_std(&opts);
 391         for (i = 0; i < diff_queued_diff.nr; ++i) {
 392                 struct path_list_item *item;
 393                 struct rename *re;
 394                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 395                 if (pair->status != 'R') {
 396                         diff_free_filepair(pair);
 397                         continue;
 398                 }
 399                 re = xmalloc(sizeof(*re));
 400                 re->processed = 0;
 401                 re->pair = pair;
 402                 item = path_list_lookup(re->pair->one->path, entries);
 403                 if (!item)
 404                         re->src_entry = insert_stage_data(re->pair->one->path,
 405                                         o_tree, a_tree, b_tree, entries);
 406                 else
 407                         re->src_entry = item->util;
 408
 409                 item = path_list_lookup(re->pair->two->path, entries);
 410                 if (!item)
 411                         re->dst_entry = insert_stage_data(re->pair->two->path,
 412                                         o_tree, a_tree, b_tree, entries);
 413                 else
 414                         re->dst_entry = item->util;
 415                 item = path_list_insert(pair->one->path, renames);
 416                 item->util = re;
 417         }
 418         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 419         diff_queued_diff.nr = 0;
 420         diff_flush(&opts);
 421         return renames;
 422 }
 423
 424 static int update_stages(const char *path, struct diff_filespec *o,
 425                          struct diff_filespec *a, struct diff_filespec *b,
 426                          int clear)
 427 {
 428         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 429         if (clear)
 430                 if (remove_file_from_cache(path))
 431                         return -1;
 432         if (o)
 433                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 434                         return -1;
 435         if (a)
 436                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 437                         return -1;
 438         if (b)
 439                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 440                         return -1;
 441         return 0;
 442 }
 443
 444 static int remove_path(const char *name)
 445 {
 446         int ret, len;
 447         char *slash, *dirs;
 448
 449         ret = unlink(name);
 450         if (ret)
 451                 return ret;
 452         len = strlen(name);
 453         dirs = xmalloc(len+1);
 454         memcpy(dirs, name, len);
 455         dirs[len] = '\0';
 456         while ((slash = strrchr(name, '/'))) {
 457                 *slash = '\0';
 458                 len = slash - name;
 459                 if (rmdir(name) != 0)
 460                         break;
 461         }
 462         free(dirs);
 463         return ret;
 464 }
 465
 466 static int remove_file(int clean, const char *path, int no_wd)
 467 {
 468         int update_cache = index_only || clean;
 469         int update_working_directory = !index_only && !no_wd;
 470
 471         if (update_cache) {
 472                 if (!cache_dirty)
 473                         read_cache_from(current_index_file);
 474                 cache_dirty++;
 475                 if (remove_file_from_cache(path))
 476                         return -1;
 477         }
 478         if (update_working_directory) {
 479                 unlink(path);
 480                 if (errno != ENOENT || errno != EISDIR)
 481                         return -1;
 482                 remove_path(path);
 483         }
 484         return 0;
 485 }
 486
 487 static char *unique_path(const char *path, const char *branch)
 488 {
 489         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 490         int suffix = 0;
 491         struct stat st;
 492         char *p = newpath + strlen(path);
 493         strcpy(newpath, path);
 494         *(p++) = '~';
 495         strcpy(p, branch);
 496         for (; *p; ++p)
 497                 if ('/' == *p)
 498                         *p = '_';
 499         while (path_list_has_path(&current_file_set, newpath) ||
 500                path_list_has_path(&current_directory_set, newpath) ||
 501                lstat(newpath, &st) == 0)
 502                 sprintf(p, "_%d", suffix++);
 503
 504         path_list_insert(newpath, &current_file_set);
 505         return newpath;
 506 }
 507
 508 static int mkdir_p(const char *path, unsigned long mode)
 509 {
 510         /* path points to cache entries, so xstrdup before messing with it */
 511         char *buf = xstrdup(path);
 512         int result = safe_create_leading_directories(buf);
 513         free(buf);
 514         return result;
 515 }
 516
 517 static void flush_buffer(int fd, const char *buf, unsigned long size)
 518 {
 519         while (size > 0) {
 520                 long ret = xwrite(fd, buf, size);
 521                 if (ret < 0) {
 522                         /* Ignore epipe */
 523                         if (errno == EPIPE)
 524                                 break;
 525                         die("merge-recursive: %s", strerror(errno));
 526                 } else if (!ret) {
 527                         die("merge-recursive: disk full?");
 528                 }
 529                 size -= ret;
 530                 buf += ret;
 531         }
 532 }
 533
 534 static void update_file_flags(const unsigned char *sha,
 535                               unsigned mode,
 536                               const char *path,
 537                               int update_cache,
 538                               int update_wd)
 539 {
 540         if (index_only)
 541                 update_wd = 0;
 542
 543         if (update_wd) {
 544                 char type[20];
 545                 void *buf;
 546                 unsigned long size;
 547
 548                 buf = read_sha1_file(sha, type, &size);
 549                 if (!buf)
 550                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 551                 if (strcmp(type, blob_type) != 0)
 552                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 553
 554                 if (S_ISREG(mode)) {
 555                         int fd;
 556                         if (mkdir_p(path, 0777))
 557                                 die("failed to create path %s: %s", path, strerror(errno));
 558                         unlink(path);
 559                         if (mode & 0100)
 560                                 mode = 0777;
 561                         else
 562                                 mode = 0666;
 563                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 564                         if (fd < 0)
 565                                 die("failed to open %s: %s", path, strerror(errno));
 566                         flush_buffer(fd, buf, size);
 567                         close(fd);
 568                 } else if (S_ISLNK(mode)) {
 569                         char *lnk = xmalloc(size + 1);
 570                         memcpy(lnk, buf, size);
 571                         lnk[size] = '\0';
 572                         mkdir_p(path, 0777);
 573                         unlink(lnk);
 574                         symlink(lnk, path);
 575                 } else
 576                         die("do not know what to do with %06o %s '%s'",
 577                             mode, sha1_to_hex(sha), path);
 578         }
 579         if (update_cache)
 580                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 581 }
 582
 583 static void update_file(int clean,
 584                         const unsigned char *sha,
 585                         unsigned mode,
 586                         const char *path)
 587 {
 588         update_file_flags(sha, mode, path, index_only || clean, !index_only);
 589 }
 590
 591 /* Low level file merging, update and removal */
 592
 593 struct merge_file_info
 594 {
 595         unsigned char sha[20];
 596         unsigned mode;
 597         unsigned clean:1,
 598                  merge:1;
 599 };
 600
 601 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 602 {
 603         unsigned long size;
 604         char type[20];
 605
 606         if (!hashcmp(sha1, null_sha1)) {
 607                 mm->ptr = xstrdup("");
 608                 mm->size = 0;
 609                 return;
 610         }
 611
 612         mm->ptr = read_sha1_file(sha1, type, &size);
 613         if (!mm->ptr || strcmp(type, blob_type))
 614                 die("unable to read blob object %s", sha1_to_hex(sha1));
 615         mm->size = size;
 616 }
 617
 618 static struct merge_file_info merge_file(struct diff_filespec *o,
 619                 struct diff_filespec *a, struct diff_filespec *b,
 620                 const char *branch1, const char *branch2)
 621 {
 622         struct merge_file_info result;
 623         result.merge = 0;
 624         result.clean = 1;
 625
 626         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 627                 result.clean = 0;
 628                 if (S_ISREG(a->mode)) {
 629                         result.mode = a->mode;
 630                         hashcpy(result.sha, a->sha1);
 631                 } else {
 632                         result.mode = b->mode;
 633                         hashcpy(result.sha, b->sha1);
 634                 }
 635         } else {
 636                 if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
 637                         result.merge = 1;
 638
 639                 result.mode = a->mode == o->mode ? b->mode: a->mode;
 640
 641                 if (sha_eq(a->sha1, o->sha1))
 642                         hashcpy(result.sha, b->sha1);
 643                 else if (sha_eq(b->sha1, o->sha1))
 644                         hashcpy(result.sha, a->sha1);
 645                 else if (S_ISREG(a->mode)) {
 646                         mmfile_t orig, src1, src2;
 647                         mmbuffer_t result_buf;
 648                         xpparam_t xpp;
 649                         char *name1, *name2;
 650                         int merge_status;
 651
 652                         name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 653                         name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 654
 655                         fill_mm(o->sha1, &orig);
 656                         fill_mm(a->sha1, &src1);
 657                         fill_mm(b->sha1, &src2);
 658
 659                         memset(&xpp, 0, sizeof(xpp));
 660                         merge_status = xdl_merge(&orig,
 661                                                  &src1, name1,
 662                                                  &src2, name2,
 663                                                  &xpp, XDL_MERGE_ZEALOUS,
 664                                                  &result_buf);
 665                         free(name1);
 666                         free(name2);
 667                         free(orig.ptr);
 668                         free(src1.ptr);
 669                         free(src2.ptr);
 670
 671                         if ((merge_status < 0) || !result_buf.ptr)
 672                                 die("Failed to execute internal merge");
 673
 674                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 675                                             blob_type, result.sha))
 676                                 die("Unable to add %s to database",
 677                                     a->path);
 678
 679                         free(result_buf.ptr);
 680                         result.clean = (merge_status == 0);
 681                 } else {
 682                         if (!(S_ISLNK(a->mode) || S_ISLNK(b->mode)))
 683                                 die("cannot merge modes?");
 684
 685                         hashcpy(result.sha, a->sha1);
 686
 687                         if (!sha_eq(a->sha1, b->sha1))
 688                                 result.clean = 0;
 689                 }
 690         }
 691
 692         return result;
 693 }
 694
 695 static void conflict_rename_rename(struct rename *ren1,
 696                                    const char *branch1,
 697                                    struct rename *ren2,
 698                                    const char *branch2)
 699 {
 700         char *del[2];
 701         int delp = 0;
 702         const char *ren1_dst = ren1->pair->two->path;
 703         const char *ren2_dst = ren2->pair->two->path;
 704         const char *dst_name1 = ren1_dst;
 705         const char *dst_name2 = ren2_dst;
 706         if (path_list_has_path(&current_directory_set, ren1_dst)) {
 707                 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
 708                 output("%s is a directory in %s adding as %s instead",
 709                        ren1_dst, branch2, dst_name1);
 710                 remove_file(0, ren1_dst, 0);
 711         }
 712         if (path_list_has_path(&current_directory_set, ren2_dst)) {
 713                 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
 714                 output("%s is a directory in %s adding as %s instead",
 715                        ren2_dst, branch1, dst_name2);
 716                 remove_file(0, ren2_dst, 0);
 717         }
 718         update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 719         update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 720         while (delp--)
 721                 free(del[delp]);
 722 }
 723
 724 static void conflict_rename_dir(struct rename *ren1,
 725                                 const char *branch1)
 726 {
 727         char *new_path = unique_path(ren1->pair->two->path, branch1);
 728         output("Renaming %s to %s instead", ren1->pair->one->path, new_path);
 729         remove_file(0, ren1->pair->two->path, 0);
 730         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 731         free(new_path);
 732 }
 733
 734 static void conflict_rename_rename_2(struct rename *ren1,
 735                                      const char *branch1,
 736                                      struct rename *ren2,
 737                                      const char *branch2)
 738 {
 739         char *new_path1 = unique_path(ren1->pair->two->path, branch1);
 740         char *new_path2 = unique_path(ren2->pair->two->path, branch2);
 741         output("Renaming %s to %s and %s to %s instead",
 742                ren1->pair->one->path, new_path1,
 743                ren2->pair->one->path, new_path2);
 744         remove_file(0, ren1->pair->two->path, 0);
 745         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 746         update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 747         free(new_path2);
 748         free(new_path1);
 749 }
 750
 751 static int process_renames(struct path_list *a_renames,
 752                            struct path_list *b_renames,
 753                            const char *a_branch,
 754                            const char *b_branch)
 755 {
 756         int clean_merge = 1, i, j;
 757         struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 758         const struct rename *sre;
 759
 760         for (i = 0; i < a_renames->nr; i++) {
 761                 sre = a_renames->items[i].util;
 762                 path_list_insert(sre->pair->two->path, &a_by_dst)->util
 763                         = sre->dst_entry;
 764         }
 765         for (i = 0; i < b_renames->nr; i++) {
 766                 sre = b_renames->items[i].util;
 767                 path_list_insert(sre->pair->two->path, &b_by_dst)->util
 768                         = sre->dst_entry;
 769         }
 770
 771         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 772                 int compare;
 773                 char *src;
 774                 struct path_list *renames1, *renames2, *renames2Dst;
 775                 struct rename *ren1 = NULL, *ren2 = NULL;
 776                 const char *branch1, *branch2;
 777                 const char *ren1_src, *ren1_dst;
 778
 779                 if (i >= a_renames->nr) {
 780                         compare = 1;
 781                         ren2 = b_renames->items[j++].util;
 782                 } else if (j >= b_renames->nr) {
 783                         compare = -1;
 784                         ren1 = a_renames->items[i++].util;
 785                 } else {
 786                         compare = strcmp(a_renames->items[i].path,
 787                                         b_renames->items[j].path);
 788                         if (compare <= 0)
 789                                 ren1 = a_renames->items[i++].util;
 790                         if (compare >= 0)
 791                                 ren2 = b_renames->items[j++].util;
 792                 }
 793
 794                 /* TODO: refactor, so that 1/2 are not needed */
 795                 if (ren1) {
 796                         renames1 = a_renames;
 797                         renames2 = b_renames;
 798                         renames2Dst = &b_by_dst;
 799                         branch1 = a_branch;
 800                         branch2 = b_branch;
 801                 } else {
 802                         struct rename *tmp;
 803                         renames1 = b_renames;
 804                         renames2 = a_renames;
 805                         renames2Dst = &a_by_dst;
 806                         branch1 = b_branch;
 807                         branch2 = a_branch;
 808                         tmp = ren2;
 809                         ren2 = ren1;
 810                         ren1 = tmp;
 811                 }
 812                 src = ren1->pair->one->path;
 813
 814                 ren1->dst_entry->processed = 1;
 815                 ren1->src_entry->processed = 1;
 816
 817                 if (ren1->processed)
 818                         continue;
 819                 ren1->processed = 1;
 820
 821                 ren1_src = ren1->pair->one->path;
 822                 ren1_dst = ren1->pair->two->path;
 823
 824                 if (ren2) {
 825                         const char *ren2_src = ren2->pair->one->path;
 826                         const char *ren2_dst = ren2->pair->two->path;
 827                         /* Renamed in 1 and renamed in 2 */
 828                         if (strcmp(ren1_src, ren2_src) != 0)
 829                                 die("ren1.src != ren2.src");
 830                         ren2->dst_entry->processed = 1;
 831                         ren2->processed = 1;
 832                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 833                                 clean_merge = 0;
 834                                 output("CONFLICT (rename/rename): "
 835                                        "Rename %s->%s in branch %s "
 836                                        "rename %s->%s in %s",
 837                                        src, ren1_dst, branch1,
 838                                        src, ren2_dst, branch2);
 839                                 conflict_rename_rename(ren1, branch1, ren2, branch2);
 840                         } else {
 841                                 struct merge_file_info mfi;
 842                                 remove_file(1, ren1_src, 1);
 843                                 mfi = merge_file(ren1->pair->one,
 844                                                  ren1->pair->two,
 845                                                  ren2->pair->two,
 846                                                  branch1,
 847                                                  branch2);
 848                                 if (mfi.merge || !mfi.clean)
 849                                         output("Renaming %s->%s", src, ren1_dst);
 850
 851                                 if (mfi.merge)
 852                                         output("Auto-merging %s", ren1_dst);
 853
 854                                 if (!mfi.clean) {
 855                                         output("CONFLICT (content): merge conflict in %s",
 856                                                ren1_dst);
 857                                         clean_merge = 0;
 858
 859                                         if (!index_only)
 860                                                 update_stages(ren1_dst,
 861                                                               ren1->pair->one,
 862                                                               ren1->pair->two,
 863                                                               ren2->pair->two,
 864                                                               1 /* clear */);
 865                                 }
 866                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 867                         }
 868                 } else {
 869                         /* Renamed in 1, maybe changed in 2 */
 870                         struct path_list_item *item;
 871                         /* we only use sha1 and mode of these */
 872                         struct diff_filespec src_other, dst_other;
 873                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 874
 875                         remove_file(1, ren1_src, index_only);
 876
 877                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 878                         src_other.mode = ren1->src_entry->stages[stage].mode;
 879                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 880                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 881
 882                         try_merge = 0;
 883
 884                         if (path_list_has_path(&current_directory_set, ren1_dst)) {
 885                                 clean_merge = 0;
 886                                 output("CONFLICT (rename/directory): Rename %s->%s in %s "
 887                                        " directory %s added in %s",
 888                                        ren1_src, ren1_dst, branch1,
 889                                        ren1_dst, branch2);
 890                                 conflict_rename_dir(ren1, branch1);
 891                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 892                                 clean_merge = 0;
 893                                 output("CONFLICT (rename/delete): Rename %s->%s in %s "
 894                                        "and deleted in %s",
 895                                        ren1_src, ren1_dst, branch1,
 896                                        branch2);
 897                                 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 898                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 899                                 const char *new_path;
 900                                 clean_merge = 0;
 901                                 try_merge = 1;
 902                                 output("CONFLICT (rename/add): Rename %s->%s in %s. "
 903                                        "%s added in %s",
 904                                        ren1_src, ren1_dst, branch1,
 905                                        ren1_dst, branch2);
 906                                 new_path = unique_path(ren1_dst, branch2);
 907                                 output("Adding as %s instead", new_path);
 908                                 update_file(0, dst_other.sha1, dst_other.mode, new_path);
 909                         } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
 910                                 ren2 = item->util;
 911                                 clean_merge = 0;
 912                                 ren2->processed = 1;
 913                                 output("CONFLICT (rename/rename): Rename %s->%s in %s. "
 914                                        "Rename %s->%s in %s",
 915                                        ren1_src, ren1_dst, branch1,
 916                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
 917                                 conflict_rename_rename_2(ren1, branch1, ren2, branch2);
 918                         } else
 919                                 try_merge = 1;
 920
 921                         if (try_merge) {
 922                                 struct diff_filespec *o, *a, *b;
 923                                 struct merge_file_info mfi;
 924                                 src_other.path = (char *)ren1_src;
 925
 926                                 o = ren1->pair->one;
 927                                 if (a_renames == renames1) {
 928                                         a = ren1->pair->two;
 929                                         b = &src_other;
 930                                 } else {
 931                                         b = ren1->pair->two;
 932                                         a = &src_other;
 933                                 }
 934                                 mfi = merge_file(o, a, b,
 935                                                 a_branch, b_branch);
 936
 937                                 if (mfi.merge || !mfi.clean)
 938                                         output("Renaming %s => %s", ren1_src, ren1_dst);
 939                                 if (mfi.merge)
 940                                         output("Auto-merging %s", ren1_dst);
 941                                 if (!mfi.clean) {
 942                                         output("CONFLICT (rename/modify): Merge conflict in %s",
 943                                                ren1_dst);
 944                                         clean_merge = 0;
 945
 946                                         if (!index_only)
 947                                                 update_stages(ren1_dst,
 948                                                                 o, a, b, 1);
 949                                 }
 950                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 951                         }
 952                 }
 953         }
 954         path_list_clear(&a_by_dst, 0);
 955         path_list_clear(&b_by_dst, 0);
 956
 957         if (cache_dirty)
 958                 flush_cache();
 959         return clean_merge;
 960 }
 961
 962 static unsigned char *has_sha(const unsigned char *sha)
 963 {
 964         return is_null_sha1(sha) ? NULL: (unsigned char *)sha;
 965 }
 966
 967 /* Per entry merge function */
 968 static int process_entry(const char *path, struct stage_data *entry,
 969                          const char *branch1,
 970                          const char *branch2)
 971 {
 972         /*
 973         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
 974         print_index_entry("\tpath: ", entry);
 975         */
 976         int clean_merge = 1;
 977         unsigned char *o_sha = has_sha(entry->stages[1].sha);
 978         unsigned char *a_sha = has_sha(entry->stages[2].sha);
 979         unsigned char *b_sha = has_sha(entry->stages[3].sha);
 980         unsigned o_mode = entry->stages[1].mode;
 981         unsigned a_mode = entry->stages[2].mode;
 982         unsigned b_mode = entry->stages[3].mode;
 983
 984         if (o_sha && (!a_sha || !b_sha)) {
 985                 /* Case A: Deleted in one */
 986                 if ((!a_sha && !b_sha) ||
 987                     (sha_eq(a_sha, o_sha) && !b_sha) ||
 988                     (!a_sha && sha_eq(b_sha, o_sha))) {
 989                         /* Deleted in both or deleted in one and
 990                          * unchanged in the other */
 991                         if (a_sha)
 992                                 output("Removing %s", path);
 993                         /* do not touch working file if it did not exist */
 994                         remove_file(1, path, !a_sha);
 995                 } else {
 996                         /* Deleted in one and changed in the other */
 997                         clean_merge = 0;
 998                         if (!a_sha) {
 999                                 output("CONFLICT (delete/modify): %s deleted in %s "
1000                                        "and modified in %s. Version %s of %s left in tree.",
1001                                        path, branch1,
1002                                        branch2, branch2, path);
1003                                 update_file(0, b_sha, b_mode, path);
1004                         } else {
1005                                 output("CONFLICT (delete/modify): %s deleted in %s "
1006                                        "and modified in %s. Version %s of %s left in tree.",
1007                                        path, branch2,
1008                                        branch1, branch1, path);
1009                                 update_file(0, a_sha, a_mode, path);
1010                         }
1011                 }
1012
1013         } else if ((!o_sha && a_sha && !b_sha) ||
1014                    (!o_sha && !a_sha && b_sha)) {
1015                 /* Case B: Added in one. */
1016                 const char *add_branch;
1017                 const char *other_branch;
1018                 unsigned mode;
1019                 const unsigned char *sha;
1020                 const char *conf;
1021
1022                 if (a_sha) {
1023                         add_branch = branch1;
1024                         other_branch = branch2;
1025                         mode = a_mode;
1026                         sha = a_sha;
1027                         conf = "file/directory";
1028                 } else {
1029                         add_branch = branch2;
1030                         other_branch = branch1;
1031                         mode = b_mode;
1032                         sha = b_sha;
1033                         conf = "directory/file";
1034                 }
1035                 if (path_list_has_path(&current_directory_set, path)) {
1036                         const char *new_path = unique_path(path, add_branch);
1037                         clean_merge = 0;
1038                         output("CONFLICT (%s): There is a directory with name %s in %s. "
1039                                "Adding %s as %s",
1040                                conf, path, other_branch, path, new_path);
1041                         remove_file(0, path, 0);
1042                         update_file(0, sha, mode, new_path);
1043                 } else {
1044                         output("Adding %s", path);
1045                         update_file(1, sha, mode, path);
1046                 }
1047         } else if (a_sha && b_sha) {
1048                 /* Case C: Added in both (check for same permissions) and */
1049                 /* case D: Modified in both, but differently. */
1050                 const char *reason = "content";
1051                 struct merge_file_info mfi;
1052                 struct diff_filespec o, a, b;
1053
1054                 if (!o_sha) {
1055                         reason = "add/add";
1056                         o_sha = (unsigned char *)null_sha1;
1057                 }
1058                 output("Auto-merging %s", path);
1059                 o.path = a.path = b.path = (char *)path;
1060                 hashcpy(o.sha1, o_sha);
1061                 o.mode = o_mode;
1062                 hashcpy(a.sha1, a_sha);
1063                 a.mode = a_mode;
1064                 hashcpy(b.sha1, b_sha);
1065                 b.mode = b_mode;
1066
1067                 mfi = merge_file(&o, &a, &b,
1068                                  branch1, branch2);
1069
1070                 if (mfi.clean)
1071                         update_file(1, mfi.sha, mfi.mode, path);
1072                 else {
1073                         clean_merge = 0;
1074                         output("CONFLICT (%s): Merge conflict in %s",
1075                                         reason, path);
1076
1077                         if (index_only)
1078                                 update_file(0, mfi.sha, mfi.mode, path);
1079                         else
1080                                 update_file_flags(mfi.sha, mfi.mode, path,
1081                                               0 /* update_cache */, 1 /* update_working_directory */);
1082                 }
1083         } else
1084                 die("Fatal merge failure, shouldn't happen.");
1085
1086         if (cache_dirty)
1087                 flush_cache();
1088
1089         return clean_merge;
1090 }
1091
1092 static int merge_trees(struct tree *head,
1093                        struct tree *merge,
1094                        struct tree *common,
1095                        const char *branch1,
1096                        const char *branch2,
1097                        struct tree **result)
1098 {
1099         int code, clean;
1100         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1101                 output("Already uptodate!");
1102                 *result = head;
1103                 return 1;
1104         }
1105
1106         code = git_merge_trees(index_only, common, head, merge);
1107
1108         if (code != 0)
1109                 die("merging of trees %s and %s failed",
1110                     sha1_to_hex(head->object.sha1),
1111                     sha1_to_hex(merge->object.sha1));
1112
1113         *result = git_write_tree();
1114
1115         if (!*result) {
1116                 struct path_list *entries, *re_head, *re_merge;
1117                 int i;
1118                 path_list_clear(&current_file_set, 1);
1119                 path_list_clear(&current_directory_set, 1);
1120                 get_files_dirs(head);
1121                 get_files_dirs(merge);
1122
1123                 entries = get_unmerged();
1124                 re_head  = get_renames(head, common, head, merge, entries);
1125                 re_merge = get_renames(merge, common, head, merge, entries);
1126                 clean = process_renames(re_head, re_merge,
1127                                 branch1, branch2);
1128                 for (i = 0; i < entries->nr; i++) {
1129                         const char *path = entries->items[i].path;
1130                         struct stage_data *e = entries->items[i].util;
1131                         if (e->processed)
1132                                 continue;
1133                         if (!process_entry(path, e, branch1, branch2))
1134                                 clean = 0;
1135                 }
1136
1137                 path_list_clear(re_merge, 0);
1138                 path_list_clear(re_head, 0);
1139                 path_list_clear(entries, 1);
1140
1141                 if (clean || index_only)
1142                         *result = git_write_tree();
1143                 else
1144                         *result = NULL;
1145         } else {
1146                 clean = 1;
1147                 printf("merging of trees %s and %s resulted in %s\n",
1148                        sha1_to_hex(head->object.sha1),
1149                        sha1_to_hex(merge->object.sha1),
1150                        sha1_to_hex((*result)->object.sha1));
1151         }
1152
1153         return clean;
1154 }
1155
1156 static struct commit_list *reverse_commit_list(struct commit_list *list)
1157 {
1158         struct commit_list *next = NULL, *current, *backup;
1159         for (current = list; current; current = backup) {
1160                 backup = current->next;
1161                 current->next = next;
1162                 next = current;
1163         }
1164         return next;
1165 }
1166
1167 /*
1168  * Merge the commits h1 and h2, return the resulting virtual
1169  * commit object and a flag indicating the cleaness of the merge.
1170  */
1171 static int merge(struct commit *h1,
1172                  struct commit *h2,
1173                  const char *branch1,
1174                  const char *branch2,
1175                  int call_depth /* =0 */,
1176                  struct commit *ancestor /* =None */,
1177                  struct commit **result)
1178 {
1179         struct commit_list *ca = NULL, *iter;
1180         struct commit *merged_common_ancestors;
1181         struct tree *mrtree;
1182         int clean;
1183
1184         output("Merging:");
1185         output_commit_title(h1);
1186         output_commit_title(h2);
1187
1188         if (ancestor)
1189                 commit_list_insert(ancestor, &ca);
1190         else
1191                 ca = reverse_commit_list(get_merge_bases(h1, h2, 1));
1192
1193         output("found %u common ancestor(s):", commit_list_count(ca));
1194         for (iter = ca; iter; iter = iter->next)
1195                 output_commit_title(iter->item);
1196
1197         merged_common_ancestors = pop_commit(&ca);
1198         if (merged_common_ancestors == NULL) {
1199                 /* if there is no common ancestor, make an empty tree */
1200                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1201
1202                 tree->object.parsed = 1;
1203                 tree->object.type = OBJ_TREE;
1204                 write_sha1_file(NULL, 0, tree_type, tree->object.sha1);
1205                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1206         }
1207
1208         for (iter = ca; iter; iter = iter->next) {
1209                 output_indent = call_depth + 1;
1210                 /*
1211                  * When the merge fails, the result contains files
1212                  * with conflict markers. The cleanness flag is
1213                  * ignored, it was never acutally used, as result of
1214                  * merge_trees has always overwritten it: the commited
1215                  * "conflicts" were already resolved.
1216                  */
1217                 merge(merged_common_ancestors, iter->item,
1218                       "Temporary merge branch 1",
1219                       "Temporary merge branch 2",
1220                       call_depth + 1,
1221                       NULL,
1222                       &merged_common_ancestors);
1223                 output_indent = call_depth;
1224
1225                 if (!merged_common_ancestors)
1226                         die("merge returned no commit");
1227         }
1228
1229         if (call_depth == 0) {
1230                 setup_index(0 /* $GIT_DIR/index */);
1231                 index_only = 0;
1232         } else {
1233                 setup_index(1 /* temporary index */);
1234                 git_read_tree(h1->tree);
1235                 index_only = 1;
1236         }
1237
1238         clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1239                             branch1, branch2, &mrtree);
1240
1241         if (!ancestor && (clean || index_only)) {
1242                 *result = make_virtual_commit(mrtree, "merged tree");
1243                 commit_list_insert(h1, &(*result)->parents);
1244                 commit_list_insert(h2, &(*result)->parents->next);
1245         } else
1246                 *result = NULL;
1247
1248         return clean;
1249 }
1250
1251 static const char *better_branch_name(const char *branch)
1252 {
1253         static char githead_env[8 + 40 + 1];
1254         char *name;
1255
1256         if (strlen(branch) != 40)
1257                 return branch;
1258         sprintf(githead_env, "GITHEAD_%s", branch);
1259         name = getenv(githead_env);
1260         return name ? name : branch;
1261 }
1262
1263 static struct commit *get_ref(const char *ref)
1264 {
1265         unsigned char sha1[20];
1266         struct object *object;
1267
1268         if (get_sha1(ref, sha1))
1269                 die("Could not resolve ref '%s'", ref);
1270         object = deref_tag(parse_object(sha1), ref, strlen(ref));
1271         if (object->type == OBJ_TREE)
1272                 return make_virtual_commit((struct tree*)object,
1273                         better_branch_name(ref));
1274         if (object->type != OBJ_COMMIT)
1275                 return NULL;
1276         if (parse_commit((struct commit *)object))
1277                 die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1278         return (struct commit *)object;
1279 }
1280
1281 int main(int argc, char *argv[])
1282 {
1283         static const char *bases[2];
1284         static unsigned bases_count = 0;
1285         int i, clean;
1286         const char *branch1, *branch2;
1287         struct commit *result, *h1, *h2;
1288
1289         git_config(git_default_config); /* core.filemode */
1290         original_index_file = getenv(INDEX_ENVIRONMENT);
1291
1292         if (!original_index_file)
1293                 original_index_file = xstrdup(git_path("index"));
1294
1295         temporary_index_file = xstrdup(git_path("mrg-rcrsv-tmp-idx"));
1296
1297         if (argc < 4)
1298                 die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1299
1300         for (i = 1; i < argc; ++i) {
1301                 if (!strcmp(argv[i], "--"))
1302                         break;
1303                 if (bases_count < sizeof(bases)/sizeof(*bases))
1304                         bases[bases_count++] = argv[i];
1305         }
1306         if (argc - i != 3) /* "--" "<head>" "<remote>" */
1307                 die("Not handling anything other than two heads merge.");
1308
1309         branch1 = argv[++i];
1310         branch2 = argv[++i];
1311
1312         h1 = get_ref(branch1);
1313         h2 = get_ref(branch2);
1314
1315         branch1 = better_branch_name(branch1);
1316         branch2 = better_branch_name(branch2);
1317         printf("Merging %s with %s\n", branch1, branch2);
1318
1319         if (bases_count == 1) {
1320                 struct commit *ancestor = get_ref(bases[0]);
1321                 clean = merge(h1, h2, branch1, branch2, 0, ancestor, &result);
1322         } else
1323                 clean = merge(h1, h2, branch1, branch2, 0, NULL, &result);
1324
1325         if (cache_dirty)
1326                 flush_cache();
1327
1328         return clean ? 0: 1;
1329 }
1330
1331 /*
1332 vim: sw=8 noet
1333 */