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 struct output_buffer
  71 {
  72         struct output_buffer *next;
  73         char *str;
  74 };
  75
  76 static struct path_list current_file_set = {NULL, 0, 0, 1};
  77 static struct path_list current_directory_set = {NULL, 0, 0, 1};
  78
  79 static int call_depth = 0;
  80 static int verbosity = 2;
  81 static int buffer_output = 1;
  82 static struct output_buffer *output_list, *output_end;
  83
  84 static int show (int v)
  85 {
  86         return (!call_depth && verbosity >= v) || verbosity >= 5;
  87 }
  88
  89 static void output(int v, const char *fmt, ...)
  90 {
  91         va_list args;
  92         va_start(args, fmt);
  93         if (buffer_output && show(v)) {
  94                 struct output_buffer *b = xmalloc(sizeof(*b));
  95                 nfvasprintf(&b->str, fmt, args);
  96                 b->next = NULL;
  97                 if (output_end)
  98                         output_end->next = b;
  99                 else
 100                         output_list = b;
 101                 output_end = b;
 102         } else if (show(v)) {
 103                 int i;
 104                 for (i = call_depth; i--;)
 105                         fputs("  ", stdout);
 106                 vfprintf(stdout, fmt, args);
 107                 fputc('\n', stdout);
 108         }
 109         va_end(args);
 110 }
 111
 112 static void flush_output()
 113 {
 114         struct output_buffer *b, *n;
 115         for (b = output_list; b; b = n) {
 116                 int i;
 117                 for (i = call_depth; i--;)
 118                         fputs("  ", stdout);
 119                 fputs(b->str, stdout);
 120                 fputc('\n', stdout);
 121                 n = b->next;
 122                 free(b->str);
 123                 free(b);
 124         }
 125         output_list = NULL;
 126         output_end = NULL;
 127 }
 128
 129 static void output_commit_title(struct commit *commit)
 130 {
 131         int i;
 132         flush_output();
 133         for (i = call_depth; i--;)
 134                 fputs("  ", stdout);
 135         if (commit->util)
 136                 printf("virtual %s\n", (char *)commit->util);
 137         else {
 138                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 139                 if (parse_commit(commit) != 0)
 140                         printf("(bad commit)\n");
 141                 else {
 142                         const char *s;
 143                         int len;
 144                         for (s = commit->buffer; *s; s++)
 145                                 if (*s == '\n' && s[1] == '\n') {
 146                                         s += 2;
 147                                         break;
 148                                 }
 149                         for (len = 0; s[len] && '\n' != s[len]; len++)
 150                                 ; /* do nothing */
 151                         printf("%.*s\n", len, s);
 152                 }
 153         }
 154 }
 155
 156 static struct cache_entry *make_cache_entry(unsigned int mode,
 157                 const unsigned char *sha1, const char *path, int stage, int refresh)
 158 {
 159         int size, len;
 160         struct cache_entry *ce;
 161
 162         if (!verify_path(path))
 163                 return NULL;
 164
 165         len = strlen(path);
 166         size = cache_entry_size(len);
 167         ce = xcalloc(1, size);
 168
 169         hashcpy(ce->sha1, sha1);
 170         memcpy(ce->name, path, len);
 171         ce->ce_flags = create_ce_flags(len, stage);
 172         ce->ce_mode = create_ce_mode(mode);
 173
 174         if (refresh)
 175                 return refresh_cache_entry(ce, 0);
 176
 177         return ce;
 178 }
 179
 180 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 181                 const char *path, int stage, int refresh, int options)
 182 {
 183         struct cache_entry *ce;
 184         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 185         if (!ce)
 186                 return error("cache_addinfo failed: %s", strerror(cache_errno));
 187         return add_cache_entry(ce, options);
 188 }
 189
 190 /*
 191  * This is a global variable which is used in a number of places but
 192  * only written to in the 'merge' function.
 193  *
 194  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
 195  *                       don't update the working directory.
 196  *               0    => Leave unmerged entries in the cache and update
 197  *                       the working directory.
 198  */
 199 static int index_only = 0;
 200
 201 static int git_merge_trees(int index_only,
 202                            struct tree *common,
 203                            struct tree *head,
 204                            struct tree *merge)
 205 {
 206         int rc;
 207         struct object_list *trees = NULL;
 208         struct unpack_trees_options opts;
 209
 210         memset(&opts, 0, sizeof(opts));
 211         if (index_only)
 212                 opts.index_only = 1;
 213         else
 214                 opts.update = 1;
 215         opts.merge = 1;
 216         opts.head_idx = 2;
 217         opts.fn = threeway_merge;
 218
 219         object_list_append(&common->object, &trees);
 220         object_list_append(&head->object, &trees);
 221         object_list_append(&merge->object, &trees);
 222
 223         rc = unpack_trees(trees, &opts);
 224         cache_tree_free(&active_cache_tree);
 225         return rc;
 226 }
 227
 228 static int unmerged_index(void)
 229 {
 230         int i;
 231         for (i = 0; i < active_nr; i++) {
 232                 struct cache_entry *ce = active_cache[i];
 233                 if (ce_stage(ce))
 234                         return 1;
 235         }
 236         return 0;
 237 }
 238
 239 static struct tree *git_write_tree(void)
 240 {
 241         struct tree *result = NULL;
 242
 243         if (unmerged_index())
 244                 return NULL;
 245
 246         if (!active_cache_tree)
 247                 active_cache_tree = cache_tree();
 248
 249         if (!cache_tree_fully_valid(active_cache_tree) &&
 250             cache_tree_update(active_cache_tree,
 251                               active_cache, active_nr, 0, 0) < 0)
 252                 die("error building trees");
 253
 254         result = lookup_tree(active_cache_tree->sha1);
 255
 256         return result;
 257 }
 258
 259 static int save_files_dirs(const unsigned char *sha1,
 260                 const char *base, int baselen, const char *path,
 261                 unsigned int mode, int stage)
 262 {
 263         int len = strlen(path);
 264         char *newpath = xmalloc(baselen + len + 1);
 265         memcpy(newpath, base, baselen);
 266         memcpy(newpath + baselen, path, len);
 267         newpath[baselen + len] = '\0';
 268
 269         if (S_ISDIR(mode))
 270                 path_list_insert(newpath, &current_directory_set);
 271         else
 272                 path_list_insert(newpath, &current_file_set);
 273         free(newpath);
 274
 275         return READ_TREE_RECURSIVE;
 276 }
 277
 278 static int get_files_dirs(struct tree *tree)
 279 {
 280         int n;
 281         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
 282                 return 0;
 283         n = current_file_set.nr + current_directory_set.nr;
 284         return n;
 285 }
 286
 287 /*
 288  * Returns a index_entry instance which doesn't have to correspond to
 289  * a real cache entry in Git's index.
 290  */
 291 static struct stage_data *insert_stage_data(const char *path,
 292                 struct tree *o, struct tree *a, struct tree *b,
 293                 struct path_list *entries)
 294 {
 295         struct path_list_item *item;
 296         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 297         get_tree_entry(o->object.sha1, path,
 298                         e->stages[1].sha, &e->stages[1].mode);
 299         get_tree_entry(a->object.sha1, path,
 300                         e->stages[2].sha, &e->stages[2].mode);
 301         get_tree_entry(b->object.sha1, path,
 302                         e->stages[3].sha, &e->stages[3].mode);
 303         item = path_list_insert(path, entries);
 304         item->util = e;
 305         return e;
 306 }
 307
 308 /*
 309  * Create a dictionary mapping file names to stage_data objects. The
 310  * dictionary contains one entry for every path with a non-zero stage entry.
 311  */
 312 static struct path_list *get_unmerged(void)
 313 {
 314         struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
 315         int i;
 316
 317         unmerged->strdup_paths = 1;
 318
 319         for (i = 0; i < active_nr; i++) {
 320                 struct path_list_item *item;
 321                 struct stage_data *e;
 322                 struct cache_entry *ce = active_cache[i];
 323                 if (!ce_stage(ce))
 324                         continue;
 325
 326                 item = path_list_lookup(ce->name, unmerged);
 327                 if (!item) {
 328                         item = path_list_insert(ce->name, unmerged);
 329                         item->util = xcalloc(1, sizeof(struct stage_data));
 330                 }
 331                 e = item->util;
 332                 e->stages[ce_stage(ce)].mode = ntohl(ce->ce_mode);
 333                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 334         }
 335
 336         return unmerged;
 337 }
 338
 339 struct rename
 340 {
 341         struct diff_filepair *pair;
 342         struct stage_data *src_entry;
 343         struct stage_data *dst_entry;
 344         unsigned processed:1;
 345 };
 346
 347 /*
 348  * Get information of all renames which occured between 'o_tree' and
 349  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 350  * 'b_tree') to be able to associate the correct cache entries with
 351  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 352  */
 353 static struct path_list *get_renames(struct tree *tree,
 354                                         struct tree *o_tree,
 355                                         struct tree *a_tree,
 356                                         struct tree *b_tree,
 357                                         struct path_list *entries)
 358 {
 359         int i;
 360         struct path_list *renames;
 361         struct diff_options opts;
 362
 363         renames = xcalloc(1, sizeof(struct path_list));
 364         diff_setup(&opts);
 365         opts.recursive = 1;
 366         opts.detect_rename = DIFF_DETECT_RENAME;
 367         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 368         if (diff_setup_done(&opts) < 0)
 369                 die("diff setup failed");
 370         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 371         diffcore_std(&opts);
 372         for (i = 0; i < diff_queued_diff.nr; ++i) {
 373                 struct path_list_item *item;
 374                 struct rename *re;
 375                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 376                 if (pair->status != 'R') {
 377                         diff_free_filepair(pair);
 378                         continue;
 379                 }
 380                 re = xmalloc(sizeof(*re));
 381                 re->processed = 0;
 382                 re->pair = pair;
 383                 item = path_list_lookup(re->pair->one->path, entries);
 384                 if (!item)
 385                         re->src_entry = insert_stage_data(re->pair->one->path,
 386                                         o_tree, a_tree, b_tree, entries);
 387                 else
 388                         re->src_entry = item->util;
 389
 390                 item = path_list_lookup(re->pair->two->path, entries);
 391                 if (!item)
 392                         re->dst_entry = insert_stage_data(re->pair->two->path,
 393                                         o_tree, a_tree, b_tree, entries);
 394                 else
 395                         re->dst_entry = item->util;
 396                 item = path_list_insert(pair->one->path, renames);
 397                 item->util = re;
 398         }
 399         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 400         diff_queued_diff.nr = 0;
 401         diff_flush(&opts);
 402         return renames;
 403 }
 404
 405 static int update_stages(const char *path, struct diff_filespec *o,
 406                          struct diff_filespec *a, struct diff_filespec *b,
 407                          int clear)
 408 {
 409         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 410         if (clear)
 411                 if (remove_file_from_cache(path))
 412                         return -1;
 413         if (o)
 414                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 415                         return -1;
 416         if (a)
 417                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 418                         return -1;
 419         if (b)
 420                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 421                         return -1;
 422         return 0;
 423 }
 424
 425 static int remove_path(const char *name)
 426 {
 427         int ret, len;
 428         char *slash, *dirs;
 429
 430         ret = unlink(name);
 431         if (ret)
 432                 return ret;
 433         len = strlen(name);
 434         dirs = xmalloc(len+1);
 435         memcpy(dirs, name, len);
 436         dirs[len] = '\0';
 437         while ((slash = strrchr(name, '/'))) {
 438                 *slash = '\0';
 439                 len = slash - name;
 440                 if (rmdir(name) != 0)
 441                         break;
 442         }
 443         free(dirs);
 444         return ret;
 445 }
 446
 447 static int remove_file(int clean, const char *path, int no_wd)
 448 {
 449         int update_cache = index_only || clean;
 450         int update_working_directory = !index_only && !no_wd;
 451
 452         if (update_cache) {
 453                 if (remove_file_from_cache(path))
 454                         return -1;
 455         }
 456         if (update_working_directory) {
 457                 unlink(path);
 458                 if (errno != ENOENT || errno != EISDIR)
 459                         return -1;
 460                 remove_path(path);
 461         }
 462         return 0;
 463 }
 464
 465 static char *unique_path(const char *path, const char *branch)
 466 {
 467         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 468         int suffix = 0;
 469         struct stat st;
 470         char *p = newpath + strlen(path);
 471         strcpy(newpath, path);
 472         *(p++) = '~';
 473         strcpy(p, branch);
 474         for (; *p; ++p)
 475                 if ('/' == *p)
 476                         *p = '_';
 477         while (path_list_has_path(&current_file_set, newpath) ||
 478                path_list_has_path(&current_directory_set, newpath) ||
 479                lstat(newpath, &st) == 0)
 480                 sprintf(p, "_%d", suffix++);
 481
 482         path_list_insert(newpath, &current_file_set);
 483         return newpath;
 484 }
 485
 486 static int mkdir_p(const char *path, unsigned long mode)
 487 {
 488         /* path points to cache entries, so xstrdup before messing with it */
 489         char *buf = xstrdup(path);
 490         int result = safe_create_leading_directories(buf);
 491         free(buf);
 492         return result;
 493 }
 494
 495 static void flush_buffer(int fd, const char *buf, unsigned long size)
 496 {
 497         while (size > 0) {
 498                 long ret = write_in_full(fd, buf, size);
 499                 if (ret < 0) {
 500                         /* Ignore epipe */
 501                         if (errno == EPIPE)
 502                                 break;
 503                         die("merge-recursive: %s", strerror(errno));
 504                 } else if (!ret) {
 505                         die("merge-recursive: disk full?");
 506                 }
 507                 size -= ret;
 508                 buf += ret;
 509         }
 510 }
 511
 512 static void update_file_flags(const unsigned char *sha,
 513                               unsigned mode,
 514                               const char *path,
 515                               int update_cache,
 516                               int update_wd)
 517 {
 518         if (index_only)
 519                 update_wd = 0;
 520
 521         if (update_wd) {
 522                 char type[20];
 523                 void *buf;
 524                 unsigned long size;
 525
 526                 buf = read_sha1_file(sha, type, &size);
 527                 if (!buf)
 528                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 529                 if (strcmp(type, blob_type) != 0)
 530                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 531
 532                 if (S_ISREG(mode)) {
 533                         int fd;
 534                         if (mkdir_p(path, 0777))
 535                                 die("failed to create path %s: %s", path, strerror(errno));
 536                         unlink(path);
 537                         if (mode & 0100)
 538                                 mode = 0777;
 539                         else
 540                                 mode = 0666;
 541                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 542                         if (fd < 0)
 543                                 die("failed to open %s: %s", path, strerror(errno));
 544                         flush_buffer(fd, buf, size);
 545                         close(fd);
 546                 } else if (S_ISLNK(mode)) {
 547                         char *lnk = xmalloc(size + 1);
 548                         memcpy(lnk, buf, size);
 549                         lnk[size] = '\0';
 550                         mkdir_p(path, 0777);
 551                         unlink(lnk);
 552                         symlink(lnk, path);
 553                 } else
 554                         die("do not know what to do with %06o %s '%s'",
 555                             mode, sha1_to_hex(sha), path);
 556         }
 557         if (update_cache)
 558                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 559 }
 560
 561 static void update_file(int clean,
 562                         const unsigned char *sha,
 563                         unsigned mode,
 564                         const char *path)
 565 {
 566         update_file_flags(sha, mode, path, index_only || clean, !index_only);
 567 }
 568
 569 /* Low level file merging, update and removal */
 570
 571 struct merge_file_info
 572 {
 573         unsigned char sha[20];
 574         unsigned mode;
 575         unsigned clean:1,
 576                  merge:1;
 577 };
 578
 579 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 580 {
 581         unsigned long size;
 582         char type[20];
 583
 584         if (!hashcmp(sha1, null_sha1)) {
 585                 mm->ptr = xstrdup("");
 586                 mm->size = 0;
 587                 return;
 588         }
 589
 590         mm->ptr = read_sha1_file(sha1, type, &size);
 591         if (!mm->ptr || strcmp(type, blob_type))
 592                 die("unable to read blob object %s", sha1_to_hex(sha1));
 593         mm->size = size;
 594 }
 595
 596 static struct merge_file_info merge_file(struct diff_filespec *o,
 597                 struct diff_filespec *a, struct diff_filespec *b,
 598                 const char *branch1, const char *branch2)
 599 {
 600         struct merge_file_info result;
 601         result.merge = 0;
 602         result.clean = 1;
 603
 604         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 605                 result.clean = 0;
 606                 if (S_ISREG(a->mode)) {
 607                         result.mode = a->mode;
 608                         hashcpy(result.sha, a->sha1);
 609                 } else {
 610                         result.mode = b->mode;
 611                         hashcpy(result.sha, b->sha1);
 612                 }
 613         } else {
 614                 if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
 615                         result.merge = 1;
 616
 617                 result.mode = a->mode == o->mode ? b->mode: a->mode;
 618
 619                 if (sha_eq(a->sha1, o->sha1))
 620                         hashcpy(result.sha, b->sha1);
 621                 else if (sha_eq(b->sha1, o->sha1))
 622                         hashcpy(result.sha, a->sha1);
 623                 else if (S_ISREG(a->mode)) {
 624                         mmfile_t orig, src1, src2;
 625                         mmbuffer_t result_buf;
 626                         xpparam_t xpp;
 627                         char *name1, *name2;
 628                         int merge_status;
 629
 630                         name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 631                         name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 632
 633                         fill_mm(o->sha1, &orig);
 634                         fill_mm(a->sha1, &src1);
 635                         fill_mm(b->sha1, &src2);
 636
 637                         memset(&xpp, 0, sizeof(xpp));
 638                         merge_status = xdl_merge(&orig,
 639                                                  &src1, name1,
 640                                                  &src2, name2,
 641                                                  &xpp, XDL_MERGE_ZEALOUS,
 642                                                  &result_buf);
 643                         free(name1);
 644                         free(name2);
 645                         free(orig.ptr);
 646                         free(src1.ptr);
 647                         free(src2.ptr);
 648
 649                         if ((merge_status < 0) || !result_buf.ptr)
 650                                 die("Failed to execute internal merge");
 651
 652                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 653                                             blob_type, result.sha))
 654                                 die("Unable to add %s to database",
 655                                     a->path);
 656
 657                         free(result_buf.ptr);
 658                         result.clean = (merge_status == 0);
 659                 } else {
 660                         if (!(S_ISLNK(a->mode) || S_ISLNK(b->mode)))
 661                                 die("cannot merge modes?");
 662
 663                         hashcpy(result.sha, a->sha1);
 664
 665                         if (!sha_eq(a->sha1, b->sha1))
 666                                 result.clean = 0;
 667                 }
 668         }
 669
 670         return result;
 671 }
 672
 673 static void conflict_rename_rename(struct rename *ren1,
 674                                    const char *branch1,
 675                                    struct rename *ren2,
 676                                    const char *branch2)
 677 {
 678         char *del[2];
 679         int delp = 0;
 680         const char *ren1_dst = ren1->pair->two->path;
 681         const char *ren2_dst = ren2->pair->two->path;
 682         const char *dst_name1 = ren1_dst;
 683         const char *dst_name2 = ren2_dst;
 684         if (path_list_has_path(&current_directory_set, ren1_dst)) {
 685                 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
 686                 output(1, "%s is a directory in %s adding as %s instead",
 687                        ren1_dst, branch2, dst_name1);
 688                 remove_file(0, ren1_dst, 0);
 689         }
 690         if (path_list_has_path(&current_directory_set, ren2_dst)) {
 691                 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
 692                 output(1, "%s is a directory in %s adding as %s instead",
 693                        ren2_dst, branch1, dst_name2);
 694                 remove_file(0, ren2_dst, 0);
 695         }
 696         update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 697         update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 698         while (delp--)
 699                 free(del[delp]);
 700 }
 701
 702 static void conflict_rename_dir(struct rename *ren1,
 703                                 const char *branch1)
 704 {
 705         char *new_path = unique_path(ren1->pair->two->path, branch1);
 706         output(1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
 707         remove_file(0, ren1->pair->two->path, 0);
 708         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 709         free(new_path);
 710 }
 711
 712 static void conflict_rename_rename_2(struct rename *ren1,
 713                                      const char *branch1,
 714                                      struct rename *ren2,
 715                                      const char *branch2)
 716 {
 717         char *new_path1 = unique_path(ren1->pair->two->path, branch1);
 718         char *new_path2 = unique_path(ren2->pair->two->path, branch2);
 719         output(1, "Renaming %s to %s and %s to %s instead",
 720                ren1->pair->one->path, new_path1,
 721                ren2->pair->one->path, new_path2);
 722         remove_file(0, ren1->pair->two->path, 0);
 723         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 724         update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 725         free(new_path2);
 726         free(new_path1);
 727 }
 728
 729 static int process_renames(struct path_list *a_renames,
 730                            struct path_list *b_renames,
 731                            const char *a_branch,
 732                            const char *b_branch)
 733 {
 734         int clean_merge = 1, i, j;
 735         struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 736         const struct rename *sre;
 737
 738         for (i = 0; i < a_renames->nr; i++) {
 739                 sre = a_renames->items[i].util;
 740                 path_list_insert(sre->pair->two->path, &a_by_dst)->util
 741                         = sre->dst_entry;
 742         }
 743         for (i = 0; i < b_renames->nr; i++) {
 744                 sre = b_renames->items[i].util;
 745                 path_list_insert(sre->pair->two->path, &b_by_dst)->util
 746                         = sre->dst_entry;
 747         }
 748
 749         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 750                 int compare;
 751                 char *src;
 752                 struct path_list *renames1, *renames2, *renames2Dst;
 753                 struct rename *ren1 = NULL, *ren2 = NULL;
 754                 const char *branch1, *branch2;
 755                 const char *ren1_src, *ren1_dst;
 756
 757                 if (i >= a_renames->nr) {
 758                         compare = 1;
 759                         ren2 = b_renames->items[j++].util;
 760                 } else if (j >= b_renames->nr) {
 761                         compare = -1;
 762                         ren1 = a_renames->items[i++].util;
 763                 } else {
 764                         compare = strcmp(a_renames->items[i].path,
 765                                         b_renames->items[j].path);
 766                         if (compare <= 0)
 767                                 ren1 = a_renames->items[i++].util;
 768                         if (compare >= 0)
 769                                 ren2 = b_renames->items[j++].util;
 770                 }
 771
 772                 /* TODO: refactor, so that 1/2 are not needed */
 773                 if (ren1) {
 774                         renames1 = a_renames;
 775                         renames2 = b_renames;
 776                         renames2Dst = &b_by_dst;
 777                         branch1 = a_branch;
 778                         branch2 = b_branch;
 779                 } else {
 780                         struct rename *tmp;
 781                         renames1 = b_renames;
 782                         renames2 = a_renames;
 783                         renames2Dst = &a_by_dst;
 784                         branch1 = b_branch;
 785                         branch2 = a_branch;
 786                         tmp = ren2;
 787                         ren2 = ren1;
 788                         ren1 = tmp;
 789                 }
 790                 src = ren1->pair->one->path;
 791
 792                 ren1->dst_entry->processed = 1;
 793                 ren1->src_entry->processed = 1;
 794
 795                 if (ren1->processed)
 796                         continue;
 797                 ren1->processed = 1;
 798
 799                 ren1_src = ren1->pair->one->path;
 800                 ren1_dst = ren1->pair->two->path;
 801
 802                 if (ren2) {
 803                         const char *ren2_src = ren2->pair->one->path;
 804                         const char *ren2_dst = ren2->pair->two->path;
 805                         /* Renamed in 1 and renamed in 2 */
 806                         if (strcmp(ren1_src, ren2_src) != 0)
 807                                 die("ren1.src != ren2.src");
 808                         ren2->dst_entry->processed = 1;
 809                         ren2->processed = 1;
 810                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 811                                 clean_merge = 0;
 812                                 output(1, "CONFLICT (rename/rename): "
 813                                        "Rename %s->%s in branch %s "
 814                                        "rename %s->%s in %s",
 815                                        src, ren1_dst, branch1,
 816                                        src, ren2_dst, branch2);
 817                                 conflict_rename_rename(ren1, branch1, ren2, branch2);
 818                         } else {
 819                                 struct merge_file_info mfi;
 820                                 remove_file(1, ren1_src, 1);
 821                                 mfi = merge_file(ren1->pair->one,
 822                                                  ren1->pair->two,
 823                                                  ren2->pair->two,
 824                                                  branch1,
 825                                                  branch2);
 826                                 if (mfi.merge || !mfi.clean)
 827                                         output(1, "Renaming %s->%s", src, ren1_dst);
 828
 829                                 if (mfi.merge)
 830                                         output(2, "Auto-merging %s", ren1_dst);
 831
 832                                 if (!mfi.clean) {
 833                                         output(1, "CONFLICT (content): merge conflict in %s",
 834                                                ren1_dst);
 835                                         clean_merge = 0;
 836
 837                                         if (!index_only)
 838                                                 update_stages(ren1_dst,
 839                                                               ren1->pair->one,
 840                                                               ren1->pair->two,
 841                                                               ren2->pair->two,
 842                                                               1 /* clear */);
 843                                 }
 844                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 845                         }
 846                 } else {
 847                         /* Renamed in 1, maybe changed in 2 */
 848                         struct path_list_item *item;
 849                         /* we only use sha1 and mode of these */
 850                         struct diff_filespec src_other, dst_other;
 851                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 852
 853                         remove_file(1, ren1_src, index_only);
 854
 855                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 856                         src_other.mode = ren1->src_entry->stages[stage].mode;
 857                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 858                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 859
 860                         try_merge = 0;
 861
 862                         if (path_list_has_path(&current_directory_set, ren1_dst)) {
 863                                 clean_merge = 0;
 864                                 output(1, "CONFLICT (rename/directory): Rename %s->%s in %s "
 865                                        " directory %s added in %s",
 866                                        ren1_src, ren1_dst, branch1,
 867                                        ren1_dst, branch2);
 868                                 conflict_rename_dir(ren1, branch1);
 869                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 870                                 clean_merge = 0;
 871                                 output(1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 872                                        "and deleted in %s",
 873                                        ren1_src, ren1_dst, branch1,
 874                                        branch2);
 875                                 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 876                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 877                                 const char *new_path;
 878                                 clean_merge = 0;
 879                                 try_merge = 1;
 880                                 output(1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 881                                        "%s added in %s",
 882                                        ren1_src, ren1_dst, branch1,
 883                                        ren1_dst, branch2);
 884                                 new_path = unique_path(ren1_dst, branch2);
 885                                 output(1, "Adding as %s instead", new_path);
 886                                 update_file(0, dst_other.sha1, dst_other.mode, new_path);
 887                         } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
 888                                 ren2 = item->util;
 889                                 clean_merge = 0;
 890                                 ren2->processed = 1;
 891                                 output(1, "CONFLICT (rename/rename): Rename %s->%s in %s. "
 892                                        "Rename %s->%s in %s",
 893                                        ren1_src, ren1_dst, branch1,
 894                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
 895                                 conflict_rename_rename_2(ren1, branch1, ren2, branch2);
 896                         } else
 897                                 try_merge = 1;
 898
 899                         if (try_merge) {
 900                                 struct diff_filespec *o, *a, *b;
 901                                 struct merge_file_info mfi;
 902                                 src_other.path = (char *)ren1_src;
 903
 904                                 o = ren1->pair->one;
 905                                 if (a_renames == renames1) {
 906                                         a = ren1->pair->two;
 907                                         b = &src_other;
 908                                 } else {
 909                                         b = ren1->pair->two;
 910                                         a = &src_other;
 911                                 }
 912                                 mfi = merge_file(o, a, b,
 913                                                 a_branch, b_branch);
 914
 915                                 if (mfi.merge || !mfi.clean)
 916                                         output(1, "Renaming %s => %s", ren1_src, ren1_dst);
 917                                 if (mfi.merge)
 918                                         output(2, "Auto-merging %s", ren1_dst);
 919                                 if (!mfi.clean) {
 920                                         output(1, "CONFLICT (rename/modify): Merge conflict in %s",
 921                                                ren1_dst);
 922                                         clean_merge = 0;
 923
 924                                         if (!index_only)
 925                                                 update_stages(ren1_dst,
 926                                                                 o, a, b, 1);
 927                                 }
 928                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 929                         }
 930                 }
 931         }
 932         path_list_clear(&a_by_dst, 0);
 933         path_list_clear(&b_by_dst, 0);
 934
 935         return clean_merge;
 936 }
 937
 938 static unsigned char *has_sha(const unsigned char *sha)
 939 {
 940         return is_null_sha1(sha) ? NULL: (unsigned char *)sha;
 941 }
 942
 943 /* Per entry merge function */
 944 static int process_entry(const char *path, struct stage_data *entry,
 945                          const char *branch1,
 946                          const char *branch2)
 947 {
 948         /*
 949         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
 950         print_index_entry("\tpath: ", entry);
 951         */
 952         int clean_merge = 1;
 953         unsigned char *o_sha = has_sha(entry->stages[1].sha);
 954         unsigned char *a_sha = has_sha(entry->stages[2].sha);
 955         unsigned char *b_sha = has_sha(entry->stages[3].sha);
 956         unsigned o_mode = entry->stages[1].mode;
 957         unsigned a_mode = entry->stages[2].mode;
 958         unsigned b_mode = entry->stages[3].mode;
 959
 960         if (o_sha && (!a_sha || !b_sha)) {
 961                 /* Case A: Deleted in one */
 962                 if ((!a_sha && !b_sha) ||
 963                     (sha_eq(a_sha, o_sha) && !b_sha) ||
 964                     (!a_sha && sha_eq(b_sha, o_sha))) {
 965                         /* Deleted in both or deleted in one and
 966                          * unchanged in the other */
 967                         if (a_sha)
 968                                 output(2, "Removing %s", path);
 969                         /* do not touch working file if it did not exist */
 970                         remove_file(1, path, !a_sha);
 971                 } else {
 972                         /* Deleted in one and changed in the other */
 973                         clean_merge = 0;
 974                         if (!a_sha) {
 975                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
 976                                        "and modified in %s. Version %s of %s left in tree.",
 977                                        path, branch1,
 978                                        branch2, branch2, path);
 979                                 update_file(0, b_sha, b_mode, path);
 980                         } else {
 981                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
 982                                        "and modified in %s. Version %s of %s left in tree.",
 983                                        path, branch2,
 984                                        branch1, branch1, path);
 985                                 update_file(0, a_sha, a_mode, path);
 986                         }
 987                 }
 988
 989         } else if ((!o_sha && a_sha && !b_sha) ||
 990                    (!o_sha && !a_sha && b_sha)) {
 991                 /* Case B: Added in one. */
 992                 const char *add_branch;
 993                 const char *other_branch;
 994                 unsigned mode;
 995                 const unsigned char *sha;
 996                 const char *conf;
 997
 998                 if (a_sha) {
 999                         add_branch = branch1;
1000                         other_branch = branch2;
1001                         mode = a_mode;
1002                         sha = a_sha;
1003                         conf = "file/directory";
1004                 } else {
1005                         add_branch = branch2;
1006                         other_branch = branch1;
1007                         mode = b_mode;
1008                         sha = b_sha;
1009                         conf = "directory/file";
1010                 }
1011                 if (path_list_has_path(&current_directory_set, path)) {
1012                         const char *new_path = unique_path(path, add_branch);
1013                         clean_merge = 0;
1014                         output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
1015                                "Adding %s as %s",
1016                                conf, path, other_branch, path, new_path);
1017                         remove_file(0, path, 0);
1018                         update_file(0, sha, mode, new_path);
1019                 } else {
1020                         output(2, "Adding %s", path);
1021                         update_file(1, sha, mode, path);
1022                 }
1023         } else if (a_sha && b_sha) {
1024                 /* Case C: Added in both (check for same permissions) and */
1025                 /* case D: Modified in both, but differently. */
1026                 const char *reason = "content";
1027                 struct merge_file_info mfi;
1028                 struct diff_filespec o, a, b;
1029
1030                 if (!o_sha) {
1031                         reason = "add/add";
1032                         o_sha = (unsigned char *)null_sha1;
1033                 }
1034                 output(2, "Auto-merging %s", path);
1035                 o.path = a.path = b.path = (char *)path;
1036                 hashcpy(o.sha1, o_sha);
1037                 o.mode = o_mode;
1038                 hashcpy(a.sha1, a_sha);
1039                 a.mode = a_mode;
1040                 hashcpy(b.sha1, b_sha);
1041                 b.mode = b_mode;
1042
1043                 mfi = merge_file(&o, &a, &b,
1044                                  branch1, branch2);
1045
1046                 if (mfi.clean)
1047                         update_file(1, mfi.sha, mfi.mode, path);
1048                 else {
1049                         clean_merge = 0;
1050                         output(1, "CONFLICT (%s): Merge conflict in %s",
1051                                         reason, path);
1052
1053                         if (index_only)
1054                                 update_file(0, mfi.sha, mfi.mode, path);
1055                         else
1056                                 update_file_flags(mfi.sha, mfi.mode, path,
1057                                               0 /* update_cache */, 1 /* update_working_directory */);
1058                 }
1059         } else
1060                 die("Fatal merge failure, shouldn't happen.");
1061
1062         return clean_merge;
1063 }
1064
1065 static int merge_trees(struct tree *head,
1066                        struct tree *merge,
1067                        struct tree *common,
1068                        const char *branch1,
1069                        const char *branch2,
1070                        struct tree **result)
1071 {
1072         int code, clean;
1073         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1074                 output(0, "Already uptodate!");
1075                 *result = head;
1076                 return 1;
1077         }
1078
1079         code = git_merge_trees(index_only, common, head, merge);
1080
1081         if (code != 0)
1082                 die("merging of trees %s and %s failed",
1083                     sha1_to_hex(head->object.sha1),
1084                     sha1_to_hex(merge->object.sha1));
1085
1086         if (unmerged_index()) {
1087                 struct path_list *entries, *re_head, *re_merge;
1088                 int i;
1089                 path_list_clear(&current_file_set, 1);
1090                 path_list_clear(&current_directory_set, 1);
1091                 get_files_dirs(head);
1092                 get_files_dirs(merge);
1093
1094                 entries = get_unmerged();
1095                 re_head  = get_renames(head, common, head, merge, entries);
1096                 re_merge = get_renames(merge, common, head, merge, entries);
1097                 clean = process_renames(re_head, re_merge,
1098                                 branch1, branch2);
1099                 for (i = 0; i < entries->nr; i++) {
1100                         const char *path = entries->items[i].path;
1101                         struct stage_data *e = entries->items[i].util;
1102                         if (e->processed)
1103                                 continue;
1104                         if (!process_entry(path, e, branch1, branch2))
1105                                 clean = 0;
1106                 }
1107
1108                 path_list_clear(re_merge, 0);
1109                 path_list_clear(re_head, 0);
1110                 path_list_clear(entries, 1);
1111
1112         }
1113         else
1114                 clean = 1;
1115
1116         if (index_only)
1117                 *result = git_write_tree();
1118
1119         return clean;
1120 }
1121
1122 static struct commit_list *reverse_commit_list(struct commit_list *list)
1123 {
1124         struct commit_list *next = NULL, *current, *backup;
1125         for (current = list; current; current = backup) {
1126                 backup = current->next;
1127                 current->next = next;
1128                 next = current;
1129         }
1130         return next;
1131 }
1132
1133 /*
1134  * Merge the commits h1 and h2, return the resulting virtual
1135  * commit object and a flag indicating the cleaness of the merge.
1136  */
1137 static int merge(struct commit *h1,
1138                  struct commit *h2,
1139                  const char *branch1,
1140                  const char *branch2,
1141                  struct commit_list *ca,
1142                  struct commit **result)
1143 {
1144         struct commit_list *iter;
1145         struct commit *merged_common_ancestors;
1146         struct tree *mrtree;
1147         int clean;
1148
1149         if (show(4)) {
1150                 output(4, "Merging:");
1151                 output_commit_title(h1);
1152                 output_commit_title(h2);
1153         }
1154
1155         if (!ca) {
1156                 ca = get_merge_bases(h1, h2, 1);
1157                 ca = reverse_commit_list(ca);
1158         }
1159
1160         if (show(5)) {
1161                 output(5, "found %u common ancestor(s):", commit_list_count(ca));
1162                 for (iter = ca; iter; iter = iter->next)
1163                         output_commit_title(iter->item);
1164         }
1165
1166         merged_common_ancestors = pop_commit(&ca);
1167         if (merged_common_ancestors == NULL) {
1168                 /* if there is no common ancestor, make an empty tree */
1169                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1170
1171                 tree->object.parsed = 1;
1172                 tree->object.type = OBJ_TREE;
1173                 write_sha1_file(NULL, 0, tree_type, tree->object.sha1);
1174                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1175         }
1176
1177         for (iter = ca; iter; iter = iter->next) {
1178                 call_depth++;
1179                 /*
1180                  * When the merge fails, the result contains files
1181                  * with conflict markers. The cleanness flag is
1182                  * ignored, it was never acutally used, as result of
1183                  * merge_trees has always overwritten it: the commited
1184                  * "conflicts" were already resolved.
1185                  */
1186                 discard_cache();
1187                 merge(merged_common_ancestors, iter->item,
1188                       "Temporary merge branch 1",
1189                       "Temporary merge branch 2",
1190                       NULL,
1191                       &merged_common_ancestors);
1192                 call_depth--;
1193
1194                 if (!merged_common_ancestors)
1195                         die("merge returned no commit");
1196         }
1197
1198         discard_cache();
1199         if (!call_depth) {
1200                 read_cache();
1201                 index_only = 0;
1202         } else
1203                 index_only = 1;
1204
1205         clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1206                             branch1, branch2, &mrtree);
1207
1208         if (index_only) {
1209                 *result = make_virtual_commit(mrtree, "merged tree");
1210                 commit_list_insert(h1, &(*result)->parents);
1211                 commit_list_insert(h2, &(*result)->parents->next);
1212         }
1213         flush_output();
1214         return clean;
1215 }
1216
1217 static const char *better_branch_name(const char *branch)
1218 {
1219         static char githead_env[8 + 40 + 1];
1220         char *name;
1221
1222         if (strlen(branch) != 40)
1223                 return branch;
1224         sprintf(githead_env, "GITHEAD_%s", branch);
1225         name = getenv(githead_env);
1226         return name ? name : branch;
1227 }
1228
1229 static struct commit *get_ref(const char *ref)
1230 {
1231         unsigned char sha1[20];
1232         struct object *object;
1233
1234         if (get_sha1(ref, sha1))
1235                 die("Could not resolve ref '%s'", ref);
1236         object = deref_tag(parse_object(sha1), ref, strlen(ref));
1237         if (object->type == OBJ_TREE)
1238                 return make_virtual_commit((struct tree*)object,
1239                         better_branch_name(ref));
1240         if (object->type != OBJ_COMMIT)
1241                 return NULL;
1242         if (parse_commit((struct commit *)object))
1243                 die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1244         return (struct commit *)object;
1245 }
1246
1247 static int merge_config(const char *var, const char *value)
1248 {
1249         if (!strcasecmp(var, "merge.verbosity")) {
1250                 verbosity = git_config_int(var, value);
1251                 return 0;
1252         }
1253         return git_default_config(var, value);
1254 }
1255
1256 int main(int argc, char *argv[])
1257 {
1258         static const char *bases[20];
1259         static unsigned bases_count = 0;
1260         int i, clean;
1261         const char *branch1, *branch2;
1262         struct commit *result, *h1, *h2;
1263         struct commit_list *ca = NULL;
1264         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1265         int index_fd;
1266
1267         git_config(merge_config);
1268         if (getenv("GIT_MERGE_VERBOSITY"))
1269                 verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1270
1271         if (argc < 4)
1272                 die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1273
1274         for (i = 1; i < argc; ++i) {
1275                 if (!strcmp(argv[i], "--"))
1276                         break;
1277                 if (bases_count < sizeof(bases)/sizeof(*bases))
1278                         bases[bases_count++] = argv[i];
1279         }
1280         if (argc - i != 3) /* "--" "<head>" "<remote>" */
1281                 die("Not handling anything other than two heads merge.");
1282
1283         branch1 = argv[++i];
1284         branch2 = argv[++i];
1285
1286         h1 = get_ref(branch1);
1287         h2 = get_ref(branch2);
1288
1289         branch1 = better_branch_name(branch1);
1290         branch2 = better_branch_name(branch2);
1291         if (verbosity >= 5)
1292                 buffer_output = 0;
1293         if (show(3))
1294                 printf("Merging %s with %s\n", branch1, branch2);
1295
1296         index_fd = hold_lock_file_for_update(lock, get_index_file(), 1);
1297
1298         for (i = 0; i < bases_count; i++) {
1299                 struct commit *ancestor = get_ref(bases[i]);
1300                 ca = commit_list_insert(ancestor, &ca);
1301         }
1302         clean = merge(h1, h2, branch1, branch2, ca, &result);
1303
1304         if (active_cache_changed &&
1305             (write_cache(index_fd, active_cache, active_nr) ||
1306              close(index_fd) || commit_lock_file(lock)))
1307                         die ("unable to write %s", get_index_file());
1308
1309         return clean ? 0: 1;
1310 }