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 "advice.h"
   7 #include "cache.h"
   8 #include "cache-tree.h"
   9 #include "commit.h"
  10 #include "blob.h"
  11 #include "builtin.h"
  12 #include "tree-walk.h"
  13 #include "diff.h"
  14 #include "diffcore.h"
  15 #include "tag.h"
  16 #include "unpack-trees.h"
  17 #include "string-list.h"
  18 #include "xdiff-interface.h"
  19 #include "ll-merge.h"
  20 #include "attr.h"
  21 #include "merge-recursive.h"
  22 #include "dir.h"
  23 #include "submodule.h"
  24
  25 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
  26                                       const char *subtree_shift)
  27 {
  28         unsigned char shifted[20];
  29
  30         if (!*subtree_shift) {
  31                 shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
  32         } else {
  33                 shift_tree_by(one->object.sha1, two->object.sha1, shifted,
  34                               subtree_shift);
  35         }
  36         if (!hashcmp(two->object.sha1, shifted))
  37                 return two;
  38         return lookup_tree(shifted);
  39 }
  40
  41 /*
  42  * A virtual commit has (const char *)commit->util set to the name.
  43  */
  44
  45 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  46 {
  47         struct commit *commit = xcalloc(1, sizeof(struct commit));
  48         commit->tree = tree;
  49         commit->util = (void*)comment;
  50         /* avoid warnings */
  51         commit->object.parsed = 1;
  52         return commit;
  53 }
  54
  55 /*
  56  * Since we use get_tree_entry(), which does not put the read object into
  57  * the object pool, we cannot rely on a == b.
  58  */
  59 static int sha_eq(const unsigned char *a, const unsigned char *b)
  60 {
  61         if (!a && !b)
  62                 return 2;
  63         return a && b && hashcmp(a, b) == 0;
  64 }
  65
  66 enum rename_type {
  67         RENAME_NORMAL = 0,
  68         RENAME_DELETE,
  69         RENAME_ONE_FILE_TO_TWO
  70 };
  71
  72 struct rename_df_conflict_info {
  73         enum rename_type rename_type;
  74         struct diff_filepair *pair1;
  75         struct diff_filepair *pair2;
  76         const char *branch1;
  77         const char *branch2;
  78         struct stage_data *dst_entry1;
  79         struct stage_data *dst_entry2;
  80 };
  81
  82 /*
  83  * Since we want to write the index eventually, we cannot reuse the index
  84  * for these (temporary) data.
  85  */
  86 struct stage_data {
  87         struct {
  88                 unsigned mode;
  89                 unsigned char sha[20];
  90         } stages[4];
  91         struct rename_df_conflict_info *rename_df_conflict_info;
  92         unsigned processed:1;
  93 };
  94
  95 static inline void setup_rename_df_conflict_info(enum rename_type rename_type,
  96                                                  struct diff_filepair *pair1,
  97                                                  struct diff_filepair *pair2,
  98                                                  const char *branch1,
  99                                                  const char *branch2,
 100                                                  struct stage_data *dst_entry1,
 101                                                  struct stage_data *dst_entry2)
 102 {
 103         struct rename_df_conflict_info *ci = xcalloc(1, sizeof(struct rename_df_conflict_info));
 104         ci->rename_type = rename_type;
 105         ci->pair1 = pair1;
 106         ci->branch1 = branch1;
 107         ci->branch2 = branch2;
 108
 109         ci->dst_entry1 = dst_entry1;
 110         dst_entry1->rename_df_conflict_info = ci;
 111         dst_entry1->processed = 0;
 112
 113         assert(!pair2 == !dst_entry2);
 114         if (dst_entry2) {
 115                 ci->dst_entry2 = dst_entry2;
 116                 ci->pair2 = pair2;
 117                 dst_entry2->rename_df_conflict_info = ci;
 118                 dst_entry2->processed = 0;
 119         }
 120 }
 121
 122 static int show(struct merge_options *o, int v)
 123 {
 124         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
 125 }
 126
 127 static void flush_output(struct merge_options *o)
 128 {
 129         if (o->obuf.len) {
 130                 fputs(o->obuf.buf, stdout);
 131                 strbuf_reset(&o->obuf);
 132         }
 133 }
 134
 135 __attribute__((format (printf, 3, 4)))
 136 static void output(struct merge_options *o, int v, const char *fmt, ...)
 137 {
 138         va_list ap;
 139
 140         if (!show(o, v))
 141                 return;
 142
 143         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 144         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 145         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 146
 147         va_start(ap, fmt);
 148         strbuf_vaddf(&o->obuf, fmt, ap);
 149         va_end(ap);
 150
 151         strbuf_add(&o->obuf, "\n", 1);
 152         if (!o->buffer_output)
 153                 flush_output(o);
 154 }
 155
 156 static void output_commit_title(struct merge_options *o, struct commit *commit)
 157 {
 158         int i;
 159         flush_output(o);
 160         for (i = o->call_depth; i--;)
 161                 fputs("  ", stdout);
 162         if (commit->util)
 163                 printf("virtual %s\n", (char *)commit->util);
 164         else {
 165                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 166                 if (parse_commit(commit) != 0)
 167                         printf("(bad commit)\n");
 168                 else {
 169                         const char *title;
 170                         int len = find_commit_subject(commit->buffer, &title);
 171                         if (len)
 172                                 printf("%.*s\n", len, title);
 173                 }
 174         }
 175 }
 176
 177 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 178                 const char *path, int stage, int refresh, int options)
 179 {
 180         struct cache_entry *ce;
 181         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 182         if (!ce)
 183                 return error("addinfo_cache failed for path '%s'", path);
 184         return add_cache_entry(ce, options);
 185 }
 186
 187 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 188 {
 189         parse_tree(tree);
 190         init_tree_desc(desc, tree->buffer, tree->size);
 191 }
 192
 193 static int git_merge_trees(int index_only,
 194                            struct tree *common,
 195                            struct tree *head,
 196                            struct tree *merge)
 197 {
 198         int rc;
 199         struct tree_desc t[3];
 200         struct unpack_trees_options opts;
 201
 202         memset(&opts, 0, sizeof(opts));
 203         if (index_only)
 204                 opts.index_only = 1;
 205         else
 206                 opts.update = 1;
 207         opts.merge = 1;
 208         opts.head_idx = 2;
 209         opts.fn = threeway_merge;
 210         opts.src_index = &the_index;
 211         opts.dst_index = &the_index;
 212         setup_unpack_trees_porcelain(&opts, "merge");
 213
 214         init_tree_desc_from_tree(t+0, common);
 215         init_tree_desc_from_tree(t+1, head);
 216         init_tree_desc_from_tree(t+2, merge);
 217
 218         rc = unpack_trees(3, t, &opts);
 219         cache_tree_free(&active_cache_tree);
 220         return rc;
 221 }
 222
 223 struct tree *write_tree_from_memory(struct merge_options *o)
 224 {
 225         struct tree *result = NULL;
 226
 227         if (unmerged_cache()) {
 228                 int i;
 229                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
 230                 for (i = 0; i < active_nr; i++) {
 231                         struct cache_entry *ce = active_cache[i];
 232                         if (ce_stage(ce))
 233                                 fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
 234                                         (int)ce_namelen(ce), ce->name);
 235                 }
 236                 die("Bug in merge-recursive.c");
 237         }
 238
 239         if (!active_cache_tree)
 240                 active_cache_tree = cache_tree();
 241
 242         if (!cache_tree_fully_valid(active_cache_tree) &&
 243             cache_tree_update(active_cache_tree,
 244                               active_cache, active_nr, 0, 0) < 0)
 245                 die("error building trees");
 246
 247         result = lookup_tree(active_cache_tree->sha1);
 248
 249         return result;
 250 }
 251
 252 static int save_files_dirs(const unsigned char *sha1,
 253                 const char *base, int baselen, const char *path,
 254                 unsigned int mode, int stage, void *context)
 255 {
 256         int len = strlen(path);
 257         char *newpath = xmalloc(baselen + len + 1);
 258         struct merge_options *o = context;
 259
 260         memcpy(newpath, base, baselen);
 261         memcpy(newpath + baselen, path, len);
 262         newpath[baselen + len] = '\0';
 263
 264         if (S_ISDIR(mode))
 265                 string_list_insert(&o->current_directory_set, newpath);
 266         else
 267                 string_list_insert(&o->current_file_set, newpath);
 268         free(newpath);
 269
 270         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 271 }
 272
 273 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 274 {
 275         int n;
 276         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 277                 return 0;
 278         n = o->current_file_set.nr + o->current_directory_set.nr;
 279         return n;
 280 }
 281
 282 /*
 283  * Returns an index_entry instance which doesn't have to correspond to
 284  * a real cache entry in Git's index.
 285  */
 286 static struct stage_data *insert_stage_data(const char *path,
 287                 struct tree *o, struct tree *a, struct tree *b,
 288                 struct string_list *entries)
 289 {
 290         struct string_list_item *item;
 291         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 292         get_tree_entry(o->object.sha1, path,
 293                         e->stages[1].sha, &e->stages[1].mode);
 294         get_tree_entry(a->object.sha1, path,
 295                         e->stages[2].sha, &e->stages[2].mode);
 296         get_tree_entry(b->object.sha1, path,
 297                         e->stages[3].sha, &e->stages[3].mode);
 298         item = string_list_insert(entries, path);
 299         item->util = e;
 300         return e;
 301 }
 302
 303 /*
 304  * Create a dictionary mapping file names to stage_data objects. The
 305  * dictionary contains one entry for every path with a non-zero stage entry.
 306  */
 307 static struct string_list *get_unmerged(void)
 308 {
 309         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 310         int i;
 311
 312         unmerged->strdup_strings = 1;
 313
 314         for (i = 0; i < active_nr; i++) {
 315                 struct string_list_item *item;
 316                 struct stage_data *e;
 317                 struct cache_entry *ce = active_cache[i];
 318                 if (!ce_stage(ce))
 319                         continue;
 320
 321                 item = string_list_lookup(unmerged, ce->name);
 322                 if (!item) {
 323                         item = string_list_insert(unmerged, ce->name);
 324                         item->util = xcalloc(1, sizeof(struct stage_data));
 325                 }
 326                 e = item->util;
 327                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 328                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 329         }
 330
 331         return unmerged;
 332 }
 333
 334 static int string_list_df_name_compare(const void *a, const void *b)
 335 {
 336         const struct string_list_item *one = a;
 337         const struct string_list_item *two = b;
 338         int onelen = strlen(one->string);
 339         int twolen = strlen(two->string);
 340         /*
 341          * Here we only care that entries for D/F conflicts are
 342          * adjacent, in particular with the file of the D/F conflict
 343          * appearing before files below the corresponding directory.
 344          * The order of the rest of the list is irrelevant for us.
 345          *
 346          * To achieve this, we sort with df_name_compare and provide
 347          * the mode S_IFDIR so that D/F conflicts will sort correctly.
 348          * We use the mode S_IFDIR for everything else for simplicity,
 349          * since in other cases any changes in their order due to
 350          * sorting cause no problems for us.
 351          */
 352         int cmp = df_name_compare(one->string, onelen, S_IFDIR,
 353                                   two->string, twolen, S_IFDIR);
 354         /*
 355          * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
 356          * that 'foo' comes before 'foo/bar'.
 357          */
 358         if (cmp)
 359                 return cmp;
 360         return onelen - twolen;
 361 }
 362
 363
 364
 365 static void make_room_for_directories_of_df_conflicts(struct merge_options *o,
 366                                                       struct string_list *entries)
 367 {
 368         /* If there are D/F conflicts, and the paths currently exist
 369          * in the working copy as a file, we want to remove them to
 370          * make room for the corresponding directory.  Such paths will
 371          * later be processed in process_df_entry() at the end.  If
 372          * the corresponding directory ends up being removed by the
 373          * merge, then the file will be reinstated at that time;
 374          * otherwise, if the file is not supposed to be removed by the
 375          * merge, the contents of the file will be placed in another
 376          * unique filename.
 377          */
 378         const char *last_file = NULL;
 379         int last_len = 0;
 380         int i;
 381
 382         /*
 383          * If we're merging merge-bases, we don't want to bother with
 384          * any working directory changes.
 385          */
 386         if (o->call_depth)
 387                 return;
 388
 389         /* Ensure D/F conflicts are adjacent in the entries list. */
 390         qsort(entries->items, entries->nr, sizeof(*entries->items),
 391               string_list_df_name_compare);
 392
 393         for (i = 0; i < entries->nr; i++) {
 394                 const char *path = entries->items[i].string;
 395                 int len = strlen(path);
 396                 struct stage_data *e = entries->items[i].util;
 397
 398                 /*
 399                  * Check if last_file & path correspond to a D/F conflict;
 400                  * i.e. whether path is last_file+'/'+<something>.
 401                  * If so, remove last_file to make room for path and friends.
 402                  */
 403                 if (last_file &&
 404                     len > last_len &&
 405                     memcmp(path, last_file, last_len) == 0 &&
 406                     path[last_len] == '/') {
 407                         output(o, 3, "Removing %s to make room for subdirectory; may re-add later.", last_file);
 408                         unlink(last_file);
 409                 }
 410
 411                 /*
 412                  * Determine whether path could exist as a file in the
 413                  * working directory as a possible D/F conflict.  This
 414                  * will only occur when it exists in stage 2 as a
 415                  * file.
 416                  */
 417                 if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
 418                         last_file = path;
 419                         last_len = len;
 420                 } else {
 421                         last_file = NULL;
 422                 }
 423         }
 424 }
 425
 426 struct rename {
 427         struct diff_filepair *pair;
 428         struct stage_data *src_entry;
 429         struct stage_data *dst_entry;
 430         unsigned processed:1;
 431 };
 432
 433 /*
 434  * Get information of all renames which occurred between 'o_tree' and
 435  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 436  * 'b_tree') to be able to associate the correct cache entries with
 437  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 438  */
 439 static struct string_list *get_renames(struct merge_options *o,
 440                                        struct tree *tree,
 441                                        struct tree *o_tree,
 442                                        struct tree *a_tree,
 443                                        struct tree *b_tree,
 444                                        struct string_list *entries)
 445 {
 446         int i;
 447         struct string_list *renames;
 448         struct diff_options opts;
 449
 450         renames = xcalloc(1, sizeof(struct string_list));
 451         diff_setup(&opts);
 452         DIFF_OPT_SET(&opts, RECURSIVE);
 453         opts.detect_rename = DIFF_DETECT_RENAME;
 454         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 455                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 456                             1000;
 457         opts.rename_score = o->rename_score;
 458         opts.show_rename_progress = o->show_rename_progress;
 459         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 460         if (diff_setup_done(&opts) < 0)
 461                 die("diff setup failed");
 462         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 463         diffcore_std(&opts);
 464         if (opts.needed_rename_limit > o->needed_rename_limit)
 465                 o->needed_rename_limit = opts.needed_rename_limit;
 466         for (i = 0; i < diff_queued_diff.nr; ++i) {
 467                 struct string_list_item *item;
 468                 struct rename *re;
 469                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 470                 if (pair->status != 'R') {
 471                         diff_free_filepair(pair);
 472                         continue;
 473                 }
 474                 re = xmalloc(sizeof(*re));
 475                 re->processed = 0;
 476                 re->pair = pair;
 477                 item = string_list_lookup(entries, re->pair->one->path);
 478                 if (!item)
 479                         re->src_entry = insert_stage_data(re->pair->one->path,
 480                                         o_tree, a_tree, b_tree, entries);
 481                 else
 482                         re->src_entry = item->util;
 483
 484                 item = string_list_lookup(entries, re->pair->two->path);
 485                 if (!item)
 486                         re->dst_entry = insert_stage_data(re->pair->two->path,
 487                                         o_tree, a_tree, b_tree, entries);
 488                 else
 489                         re->dst_entry = item->util;
 490                 item = string_list_insert(renames, pair->one->path);
 491                 item->util = re;
 492         }
 493         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 494         diff_queued_diff.nr = 0;
 495         diff_flush(&opts);
 496         return renames;
 497 }
 498
 499 static int update_stages(const char *path, const struct diff_filespec *o,
 500                          const struct diff_filespec *a,
 501                          const struct diff_filespec *b)
 502 {
 503         int clear = 1;
 504         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
 505         if (clear)
 506                 if (remove_file_from_cache(path))
 507                         return -1;
 508         if (o)
 509                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 510                         return -1;
 511         if (a)
 512                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 513                         return -1;
 514         if (b)
 515                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 516                         return -1;
 517         return 0;
 518 }
 519
 520 static int update_stages_and_entry(const char *path,
 521                                    struct stage_data *entry,
 522                                    struct diff_filespec *o,
 523                                    struct diff_filespec *a,
 524                                    struct diff_filespec *b,
 525                                    int clear)
 526 {
 527         int options;
 528
 529         entry->processed = 0;
 530         entry->stages[1].mode = o->mode;
 531         entry->stages[2].mode = a->mode;
 532         entry->stages[3].mode = b->mode;
 533         hashcpy(entry->stages[1].sha, o->sha1);
 534         hashcpy(entry->stages[2].sha, a->sha1);
 535         hashcpy(entry->stages[3].sha, b->sha1);
 536         return update_stages(path, o, a, b);
 537 }
 538
 539 static int remove_file(struct merge_options *o, int clean,
 540                        const char *path, int no_wd)
 541 {
 542         int update_cache = o->call_depth || clean;
 543         int update_working_directory = !o->call_depth && !no_wd;
 544
 545         if (update_cache) {
 546                 if (remove_file_from_cache(path))
 547                         return -1;
 548         }
 549         if (update_working_directory) {
 550                 if (remove_path(path))
 551                         return -1;
 552         }
 553         return 0;
 554 }
 555
 556 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 557 {
 558         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 559         int suffix = 0;
 560         struct stat st;
 561         char *p = newpath + strlen(path);
 562         strcpy(newpath, path);
 563         *(p++) = '~';
 564         strcpy(p, branch);
 565         for (; *p; ++p)
 566                 if ('/' == *p)
 567                         *p = '_';
 568         while (string_list_has_string(&o->current_file_set, newpath) ||
 569                string_list_has_string(&o->current_directory_set, newpath) ||
 570                lstat(newpath, &st) == 0)
 571                 sprintf(p, "_%d", suffix++);
 572
 573         string_list_insert(&o->current_file_set, newpath);
 574         return newpath;
 575 }
 576
 577 static void flush_buffer(int fd, const char *buf, unsigned long size)
 578 {
 579         while (size > 0) {
 580                 long ret = write_in_full(fd, buf, size);
 581                 if (ret < 0) {
 582                         /* Ignore epipe */
 583                         if (errno == EPIPE)
 584                                 break;
 585                         die_errno("merge-recursive");
 586                 } else if (!ret) {
 587                         die("merge-recursive: disk full?");
 588                 }
 589                 size -= ret;
 590                 buf += ret;
 591         }
 592 }
 593
 594 static int dir_in_way(const char *path, int check_working_copy)
 595 {
 596         int pos, pathlen = strlen(path);
 597         char *dirpath = xmalloc(pathlen + 2);
 598         struct stat st;
 599
 600         strcpy(dirpath, path);
 601         dirpath[pathlen] = '/';
 602         dirpath[pathlen+1] = '\0';
 603
 604         pos = cache_name_pos(dirpath, pathlen+1);
 605
 606         if (pos < 0)
 607                 pos = -1 - pos;
 608         if (pos < active_nr &&
 609             !strncmp(dirpath, active_cache[pos]->name, pathlen+1)) {
 610                 free(dirpath);
 611                 return 1;
 612         }
 613
 614         free(dirpath);
 615         return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode);
 616 }
 617
 618 static int would_lose_untracked(const char *path)
 619 {
 620         int pos = cache_name_pos(path, strlen(path));
 621
 622         if (pos < 0)
 623                 pos = -1 - pos;
 624         while (pos < active_nr &&
 625                !strcmp(path, active_cache[pos]->name)) {
 626                 /*
 627                  * If stage #0, it is definitely tracked.
 628                  * If it has stage #2 then it was tracked
 629                  * before this merge started.  All other
 630                  * cases the path was not tracked.
 631                  */
 632                 switch (ce_stage(active_cache[pos])) {
 633                 case 0:
 634                 case 2:
 635                         return 0;
 636                 }
 637                 pos++;
 638         }
 639         return file_exists(path);
 640 }
 641
 642 static int make_room_for_path(const char *path)
 643 {
 644         int status;
 645         const char *msg = "failed to create path '%s'%s";
 646
 647         status = safe_create_leading_directories_const(path);
 648         if (status) {
 649                 if (status == -3) {
 650                         /* something else exists */
 651                         error(msg, path, ": perhaps a D/F conflict?");
 652                         return -1;
 653                 }
 654                 die(msg, path, "");
 655         }
 656
 657         /*
 658          * Do not unlink a file in the work tree if we are not
 659          * tracking it.
 660          */
 661         if (would_lose_untracked(path))
 662                 return error("refusing to lose untracked file at '%s'",
 663                              path);
 664
 665         /* Successful unlink is good.. */
 666         if (!unlink(path))
 667                 return 0;
 668         /* .. and so is no existing file */
 669         if (errno == ENOENT)
 670                 return 0;
 671         /* .. but not some other error (who really cares what?) */
 672         return error(msg, path, ": perhaps a D/F conflict?");
 673 }
 674
 675 static void update_file_flags(struct merge_options *o,
 676                               const unsigned char *sha,
 677                               unsigned mode,
 678                               const char *path,
 679                               int update_cache,
 680                               int update_wd)
 681 {
 682         if (o->call_depth)
 683                 update_wd = 0;
 684
 685         if (update_wd) {
 686                 enum object_type type;
 687                 void *buf;
 688                 unsigned long size;
 689
 690                 if (S_ISGITLINK(mode)) {
 691                         /*
 692                          * We may later decide to recursively descend into
 693                          * the submodule directory and update its index
 694                          * and/or work tree, but we do not do that now.
 695                          */
 696                         update_wd = 0;
 697                         goto update_index;
 698                 }
 699
 700                 buf = read_sha1_file(sha, &type, &size);
 701                 if (!buf)
 702                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 703                 if (type != OBJ_BLOB)
 704                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 705                 if (S_ISREG(mode)) {
 706                         struct strbuf strbuf = STRBUF_INIT;
 707                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 708                                 free(buf);
 709                                 size = strbuf.len;
 710                                 buf = strbuf_detach(&strbuf, NULL);
 711                         }
 712                 }
 713
 714                 if (make_room_for_path(path) < 0) {
 715                         update_wd = 0;
 716                         free(buf);
 717                         goto update_index;
 718                 }
 719                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 720                         int fd;
 721                         if (mode & 0100)
 722                                 mode = 0777;
 723                         else
 724                                 mode = 0666;
 725                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 726                         if (fd < 0)
 727                                 die_errno("failed to open '%s'", path);
 728                         flush_buffer(fd, buf, size);
 729                         close(fd);
 730                 } else if (S_ISLNK(mode)) {
 731                         char *lnk = xmemdupz(buf, size);
 732                         safe_create_leading_directories_const(path);
 733                         unlink(path);
 734                         if (symlink(lnk, path))
 735                                 die_errno("failed to symlink '%s'", path);
 736                         free(lnk);
 737                 } else
 738                         die("do not know what to do with %06o %s '%s'",
 739                             mode, sha1_to_hex(sha), path);
 740                 free(buf);
 741         }
 742  update_index:
 743         if (update_cache)
 744                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 745 }
 746
 747 static void update_file(struct merge_options *o,
 748                         int clean,
 749                         const unsigned char *sha,
 750                         unsigned mode,
 751                         const char *path)
 752 {
 753         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 754 }
 755
 756 /* Low level file merging, update and removal */
 757
 758 struct merge_file_info {
 759         unsigned char sha[20];
 760         unsigned mode;
 761         unsigned clean:1,
 762                  merge:1;
 763 };
 764
 765 static int merge_3way(struct merge_options *o,
 766                       mmbuffer_t *result_buf,
 767                       const struct diff_filespec *one,
 768                       const struct diff_filespec *a,
 769                       const struct diff_filespec *b,
 770                       const char *branch1,
 771                       const char *branch2)
 772 {
 773         mmfile_t orig, src1, src2;
 774         struct ll_merge_options ll_opts = {0};
 775         char *base_name, *name1, *name2;
 776         int merge_status;
 777
 778         ll_opts.renormalize = o->renormalize;
 779         ll_opts.xdl_opts = o->xdl_opts;
 780
 781         if (o->call_depth) {
 782                 ll_opts.virtual_ancestor = 1;
 783                 ll_opts.variant = 0;
 784         } else {
 785                 switch (o->recursive_variant) {
 786                 case MERGE_RECURSIVE_OURS:
 787                         ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 788                         break;
 789                 case MERGE_RECURSIVE_THEIRS:
 790                         ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
 791                         break;
 792                 default:
 793                         ll_opts.variant = 0;
 794                         break;
 795                 }
 796         }
 797
 798         if (strcmp(a->path, b->path) ||
 799             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 800                 base_name = o->ancestor == NULL ? NULL :
 801                         xstrdup(mkpath("%s:%s", o->ancestor, one->path));
 802                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 803                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 804         } else {
 805                 base_name = o->ancestor == NULL ? NULL :
 806                         xstrdup(mkpath("%s", o->ancestor));
 807                 name1 = xstrdup(mkpath("%s", branch1));
 808                 name2 = xstrdup(mkpath("%s", branch2));
 809         }
 810
 811         read_mmblob(&orig, one->sha1);
 812         read_mmblob(&src1, a->sha1);
 813         read_mmblob(&src2, b->sha1);
 814
 815         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 816                                 &src1, name1, &src2, name2, &ll_opts);
 817
 818         free(name1);
 819         free(name2);
 820         free(orig.ptr);
 821         free(src1.ptr);
 822         free(src2.ptr);
 823         return merge_status;
 824 }
 825
 826 static struct merge_file_info merge_file(struct merge_options *o,
 827                                          const struct diff_filespec *one,
 828                                          const struct diff_filespec *a,
 829                                          const struct diff_filespec *b,
 830                                          const char *branch1,
 831                                          const char *branch2)
 832 {
 833         struct merge_file_info result;
 834         result.merge = 0;
 835         result.clean = 1;
 836
 837         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 838                 result.clean = 0;
 839                 if (S_ISREG(a->mode)) {
 840                         result.mode = a->mode;
 841                         hashcpy(result.sha, a->sha1);
 842                 } else {
 843                         result.mode = b->mode;
 844                         hashcpy(result.sha, b->sha1);
 845                 }
 846         } else {
 847                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 848                         result.merge = 1;
 849
 850                 /*
 851                  * Merge modes
 852                  */
 853                 if (a->mode == b->mode || a->mode == one->mode)
 854                         result.mode = b->mode;
 855                 else {
 856                         result.mode = a->mode;
 857                         if (b->mode != one->mode) {
 858                                 result.clean = 0;
 859                                 result.merge = 1;
 860                         }
 861                 }
 862
 863                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 864                         hashcpy(result.sha, b->sha1);
 865                 else if (sha_eq(b->sha1, one->sha1))
 866                         hashcpy(result.sha, a->sha1);
 867                 else if (S_ISREG(a->mode)) {
 868                         mmbuffer_t result_buf;
 869                         int merge_status;
 870
 871                         merge_status = merge_3way(o, &result_buf, one, a, b,
 872                                                   branch1, branch2);
 873
 874                         if ((merge_status < 0) || !result_buf.ptr)
 875                                 die("Failed to execute internal merge");
 876
 877                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 878                                             blob_type, result.sha))
 879                                 die("Unable to add %s to database",
 880                                     a->path);
 881
 882                         free(result_buf.ptr);
 883                         result.clean = (merge_status == 0);
 884                 } else if (S_ISGITLINK(a->mode)) {
 885                         result.clean = merge_submodule(result.sha, one->path, one->sha1,
 886                                                        a->sha1, b->sha1);
 887                 } else if (S_ISLNK(a->mode)) {
 888                         hashcpy(result.sha, a->sha1);
 889
 890                         if (!sha_eq(a->sha1, b->sha1))
 891                                 result.clean = 0;
 892                 } else {
 893                         die("unsupported object type in the tree");
 894                 }
 895         }
 896
 897         return result;
 898 }
 899
 900 static void conflict_rename_delete(struct merge_options *o,
 901                                    struct diff_filepair *pair,
 902                                    const char *rename_branch,
 903                                    const char *other_branch)
 904 {
 905         char *dest_name = pair->two->path;
 906         int df_conflict = 0;
 907
 908         output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 909                "and deleted in %s",
 910                pair->one->path, pair->two->path, rename_branch,
 911                other_branch);
 912         if (!o->call_depth)
 913                 update_stages(dest_name, NULL,
 914                               rename_branch == o->branch1 ? pair->two : NULL,
 915                               rename_branch == o->branch1 ? NULL : pair->two);
 916         if (dir_in_way(dest_name, !o->call_depth)) {
 917                 dest_name = unique_path(o, dest_name, rename_branch);
 918                 df_conflict = 1;
 919         }
 920         update_file(o, 0, pair->two->sha1, pair->two->mode, dest_name);
 921         if (df_conflict)
 922                 free(dest_name);
 923 }
 924
 925 static void conflict_rename_rename_1to2(struct merge_options *o,
 926                                         struct diff_filepair *pair1,
 927                                         const char *branch1,
 928                                         struct diff_filepair *pair2,
 929                                         const char *branch2)
 930 {
 931         /* One file was renamed in both branches, but to different names. */
 932         char *del[2];
 933         int delp = 0;
 934         const char *ren1_dst = pair1->two->path;
 935         const char *ren2_dst = pair2->two->path;
 936         const char *dst_name1 = ren1_dst;
 937         const char *dst_name2 = ren2_dst;
 938         if (dir_in_way(ren1_dst, !o->call_depth)) {
 939                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 940                 output(o, 1, "%s is a directory in %s adding as %s instead",
 941                        ren1_dst, branch2, dst_name1);
 942         }
 943         if (dir_in_way(ren2_dst, !o->call_depth)) {
 944                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 945                 output(o, 1, "%s is a directory in %s adding as %s instead",
 946                        ren2_dst, branch1, dst_name2);
 947         }
 948         if (o->call_depth) {
 949                 remove_file_from_cache(dst_name1);
 950                 remove_file_from_cache(dst_name2);
 951                 /*
 952                  * Uncomment to leave the conflicting names in the resulting tree
 953                  *
 954                  * update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
 955                  * update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
 956                  */
 957         } else {
 958                 update_stages(ren1_dst, NULL, pair1->two, NULL);
 959                 update_stages(ren2_dst, NULL, NULL, pair2->two);
 960
 961                 update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
 962                 update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
 963         }
 964         while (delp--)
 965                 free(del[delp]);
 966 }
 967
 968 static void conflict_rename_rename_2to1(struct merge_options *o,
 969                                         struct rename *ren1,
 970                                         const char *branch1,
 971                                         struct rename *ren2,
 972                                         const char *branch2)
 973 {
 974         /* Two files were renamed to the same thing. */
 975         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 976         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 977         output(o, 1, "Renaming %s to %s and %s to %s instead",
 978                ren1->pair->one->path, new_path1,
 979                ren2->pair->one->path, new_path2);
 980         remove_file(o, 0, ren1->pair->two->path, 0);
 981         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 982         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 983         free(new_path2);
 984         free(new_path1);
 985 }
 986
 987 static int process_renames(struct merge_options *o,
 988                            struct string_list *a_renames,
 989                            struct string_list *b_renames)
 990 {
 991         int clean_merge = 1, i, j;
 992         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
 993         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
 994         const struct rename *sre;
 995
 996         for (i = 0; i < a_renames->nr; i++) {
 997                 sre = a_renames->items[i].util;
 998                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
 999                         = sre->dst_entry;
1000         }
1001         for (i = 0; i < b_renames->nr; i++) {
1002                 sre = b_renames->items[i].util;
1003                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
1004                         = sre->dst_entry;
1005         }
1006
1007         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1008                 struct string_list *renames1, *renames2Dst;
1009                 struct rename *ren1 = NULL, *ren2 = NULL;
1010                 const char *branch1, *branch2;
1011                 const char *ren1_src, *ren1_dst;
1012
1013                 if (i >= a_renames->nr) {
1014                         ren2 = b_renames->items[j++].util;
1015                 } else if (j >= b_renames->nr) {
1016                         ren1 = a_renames->items[i++].util;
1017                 } else {
1018                         int compare = strcmp(a_renames->items[i].string,
1019                                              b_renames->items[j].string);
1020                         if (compare <= 0)
1021                                 ren1 = a_renames->items[i++].util;
1022                         if (compare >= 0)
1023                                 ren2 = b_renames->items[j++].util;
1024                 }
1025
1026                 /* TODO: refactor, so that 1/2 are not needed */
1027                 if (ren1) {
1028                         renames1 = a_renames;
1029                         renames2Dst = &b_by_dst;
1030                         branch1 = o->branch1;
1031                         branch2 = o->branch2;
1032                 } else {
1033                         struct rename *tmp;
1034                         renames1 = b_renames;
1035                         renames2Dst = &a_by_dst;
1036                         branch1 = o->branch2;
1037                         branch2 = o->branch1;
1038                         tmp = ren2;
1039                         ren2 = ren1;
1040                         ren1 = tmp;
1041                 }
1042
1043                 ren1->dst_entry->processed = 1;
1044                 ren1->src_entry->processed = 1;
1045
1046                 if (ren1->processed)
1047                         continue;
1048                 ren1->processed = 1;
1049
1050                 ren1_src = ren1->pair->one->path;
1051                 ren1_dst = ren1->pair->two->path;
1052
1053                 if (ren2) {
1054                         const char *ren2_src = ren2->pair->one->path;
1055                         const char *ren2_dst = ren2->pair->two->path;
1056                         /* Renamed in 1 and renamed in 2 */
1057                         if (strcmp(ren1_src, ren2_src) != 0)
1058                                 die("ren1.src != ren2.src");
1059                         ren2->dst_entry->processed = 1;
1060                         ren2->processed = 1;
1061                         if (strcmp(ren1_dst, ren2_dst) != 0) {
1062                                 setup_rename_df_conflict_info(RENAME_ONE_FILE_TO_TWO,
1063                                                               ren1->pair,
1064                                                               ren2->pair,
1065                                                               branch1,
1066                                                               branch2,
1067                                                               ren1->dst_entry,
1068                                                               ren2->dst_entry);
1069                         } else {
1070                                 remove_file(o, 1, ren1_src, 1);
1071                                 update_stages_and_entry(ren1_dst,
1072                                                         ren1->dst_entry,
1073                                                         ren1->pair->one,
1074                                                         ren1->pair->two,
1075                                                         ren2->pair->two,
1076                                                         1 /* clear */);
1077                         }
1078                 } else {
1079                         /* Renamed in 1, maybe changed in 2 */
1080                         struct string_list_item *item;
1081                         /* we only use sha1 and mode of these */
1082                         struct diff_filespec src_other, dst_other;
1083                         int try_merge;
1084
1085                         /*
1086                          * unpack_trees loads entries from common-commit
1087                          * into stage 1, from head-commit into stage 2, and
1088                          * from merge-commit into stage 3.  We keep track
1089                          * of which side corresponds to the rename.
1090                          */
1091                         int renamed_stage = a_renames == renames1 ? 2 : 3;
1092                         int other_stage =   a_renames == renames1 ? 3 : 2;
1093
1094                         remove_file(o, 1, ren1_src, o->call_depth || renamed_stage == 2);
1095
1096                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
1097                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
1098                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
1099                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1100                         try_merge = 0;
1101
1102                         if (sha_eq(src_other.sha1, null_sha1)) {
1103                                 if (dir_in_way(ren1_dst, 0 /*check_wc*/)) {
1104                                         ren1->dst_entry->processed = 0;
1105                                         setup_rename_df_conflict_info(RENAME_DELETE,
1106                                                                       ren1->pair,
1107                                                                       NULL,
1108                                                                       branch1,
1109                                                                       branch2,
1110                                                                       ren1->dst_entry,
1111                                                                       NULL);
1112                                 } else {
1113                                         clean_merge = 0;
1114                                         conflict_rename_delete(o, ren1->pair, branch1, branch2);
1115                                 }
1116                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1117                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
1118                                 /* Added file on the other side
1119                                    identical to the file being
1120                                    renamed: clean merge */
1121                                 update_file(o, 1, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
1122                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1123                                 clean_merge = 0;
1124                                 try_merge = 1;
1125                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
1126                                        "%s added in %s",
1127                                        ren1_src, ren1_dst, branch1,
1128                                        ren1_dst, branch2);
1129                                 if (o->call_depth) {
1130                                         struct merge_file_info mfi;
1131                                         struct diff_filespec one, a, b;
1132
1133                                         one.path = a.path = b.path =
1134                                                 (char *)ren1_dst;
1135                                         hashcpy(one.sha1, null_sha1);
1136                                         one.mode = 0;
1137                                         hashcpy(a.sha1, ren1->pair->two->sha1);
1138                                         a.mode = ren1->pair->two->mode;
1139                                         hashcpy(b.sha1, dst_other.sha1);
1140                                         b.mode = dst_other.mode;
1141                                         mfi = merge_file(o, &one, &a, &b,
1142                                                          branch1,
1143                                                          branch2);
1144                                         output(o, 1, "Adding merged %s", ren1_dst);
1145                                         update_file(o, 0,
1146                                                     mfi.sha,
1147                                                     mfi.mode,
1148                                                     ren1_dst);
1149                                         try_merge = 0;
1150                                 } else {
1151                                         char *new_path = unique_path(o, ren1_dst, branch2);
1152                                         output(o, 1, "Adding as %s instead", new_path);
1153                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1154                                         free(new_path);
1155                                 }
1156                         } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
1157                                 ren2 = item->util;
1158                                 clean_merge = 0;
1159                                 ren2->processed = 1;
1160                                 output(o, 1, "CONFLICT (rename/rename): "
1161                                        "Rename %s->%s in %s. "
1162                                        "Rename %s->%s in %s",
1163                                        ren1_src, ren1_dst, branch1,
1164                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1165                                 conflict_rename_rename_2to1(o, ren1, branch1, ren2, branch2);
1166                         } else
1167                                 try_merge = 1;
1168
1169                         if (try_merge) {
1170                                 struct diff_filespec *one, *a, *b;
1171                                 src_other.path = (char *)ren1_src;
1172
1173                                 one = ren1->pair->one;
1174                                 if (a_renames == renames1) {
1175                                         a = ren1->pair->two;
1176                                         b = &src_other;
1177                                 } else {
1178                                         b = ren1->pair->two;
1179                                         a = &src_other;
1180                                 }
1181                                 update_stages_and_entry(ren1_dst, ren1->dst_entry, one, a, b, 1);
1182                                 if (dir_in_way(ren1_dst, 0 /*check_wc*/)) {
1183                                         setup_rename_df_conflict_info(RENAME_NORMAL,
1184                                                                       ren1->pair,
1185                                                                       NULL,
1186                                                                       branch1,
1187                                                                       NULL,
1188                                                                       ren1->dst_entry,
1189                                                                       NULL);
1190                                 }
1191                         }
1192                 }
1193         }
1194         string_list_clear(&a_by_dst, 0);
1195         string_list_clear(&b_by_dst, 0);
1196
1197         return clean_merge;
1198 }
1199
1200 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1201 {
1202         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1203 }
1204
1205 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1206 {
1207         void *buf;
1208         enum object_type type;
1209         unsigned long size;
1210         buf = read_sha1_file(sha1, &type, &size);
1211         if (!buf)
1212                 return error("cannot read object %s", sha1_to_hex(sha1));
1213         if (type != OBJ_BLOB) {
1214                 free(buf);
1215                 return error("object %s is not a blob", sha1_to_hex(sha1));
1216         }
1217         strbuf_attach(dst, buf, size, size + 1);
1218         return 0;
1219 }
1220
1221 static int blob_unchanged(const unsigned char *o_sha,
1222                           const unsigned char *a_sha,
1223                           int renormalize, const char *path)
1224 {
1225         struct strbuf o = STRBUF_INIT;
1226         struct strbuf a = STRBUF_INIT;
1227         int ret = 0; /* assume changed for safety */
1228
1229         if (sha_eq(o_sha, a_sha))
1230                 return 1;
1231         if (!renormalize)
1232                 return 0;
1233
1234         assert(o_sha && a_sha);
1235         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1236                 goto error_return;
1237         /*
1238          * Note: binary | is used so that both renormalizations are
1239          * performed.  Comparison can be skipped if both files are
1240          * unchanged since their sha1s have already been compared.
1241          */
1242         if (renormalize_buffer(path, o.buf, o.len, &o) |
1243             renormalize_buffer(path, a.buf, o.len, &a))
1244                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1245
1246 error_return:
1247         strbuf_release(&o);
1248         strbuf_release(&a);
1249         return ret;
1250 }
1251
1252 static void handle_delete_modify(struct merge_options *o,
1253                                  const char *path,
1254                                  const char *new_path,
1255                                  unsigned char *a_sha, int a_mode,
1256                                  unsigned char *b_sha, int b_mode)
1257 {
1258         if (!a_sha) {
1259                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1260                        "and modified in %s. Version %s of %s left in tree%s%s.",
1261                        path, o->branch1,
1262                        o->branch2, o->branch2, path,
1263                        path == new_path ? "" : " at ",
1264                        path == new_path ? "" : new_path);
1265                 update_file(o, 0, b_sha, b_mode, new_path);
1266         } else {
1267                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1268                        "and modified in %s. Version %s of %s left in tree%s%s.",
1269                        path, o->branch2,
1270                        o->branch1, o->branch1, path,
1271                        path == new_path ? "" : " at ",
1272                        path == new_path ? "" : new_path);
1273                 update_file(o, 0, a_sha, a_mode, new_path);
1274         }
1275 }
1276
1277 static int merge_content(struct merge_options *o,
1278                          const char *path,
1279                          unsigned char *o_sha, int o_mode,
1280                          unsigned char *a_sha, int a_mode,
1281                          unsigned char *b_sha, int b_mode,
1282                          const char *df_rename_conflict_branch)
1283 {
1284         const char *reason = "content";
1285         struct merge_file_info mfi;
1286         struct diff_filespec one, a, b;
1287         unsigned df_conflict_remains = 0;
1288
1289         if (!o_sha) {
1290                 reason = "add/add";
1291                 o_sha = (unsigned char *)null_sha1;
1292         }
1293         one.path = a.path = b.path = (char *)path;
1294         hashcpy(one.sha1, o_sha);
1295         one.mode = o_mode;
1296         hashcpy(a.sha1, a_sha);
1297         a.mode = a_mode;
1298         hashcpy(b.sha1, b_sha);
1299         b.mode = b_mode;
1300
1301         mfi = merge_file(o, &one, &a, &b, o->branch1, o->branch2);
1302         if (df_rename_conflict_branch &&
1303             dir_in_way(path, !o->call_depth)) {
1304                 df_conflict_remains = 1;
1305         }
1306
1307         if (mfi.clean && !df_conflict_remains &&
1308             sha_eq(mfi.sha, a_sha) && mfi.mode == a.mode)
1309                 output(o, 3, "Skipped %s (merged same as existing)", path);
1310         else
1311                 output(o, 2, "Auto-merging %s", path);
1312
1313         if (!mfi.clean) {
1314                 if (S_ISGITLINK(mfi.mode))
1315                         reason = "submodule";
1316                 output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1317                                 reason, path);
1318         }
1319
1320         if (df_conflict_remains) {
1321                 char *new_path;
1322                 update_file_flags(o, mfi.sha, mfi.mode, path,
1323                                   o->call_depth || mfi.clean, 0);
1324                 new_path = unique_path(o, path, df_rename_conflict_branch);
1325                 mfi.clean = 0;
1326                 output(o, 1, "Adding as %s instead", new_path);
1327                 update_file_flags(o, mfi.sha, mfi.mode, new_path, 0, 1);
1328                 free(new_path);
1329         } else {
1330                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1331         }
1332         return mfi.clean;
1333
1334 }
1335
1336 /* Per entry merge function */
1337 static int process_entry(struct merge_options *o,
1338                          const char *path, struct stage_data *entry)
1339 {
1340         /*
1341         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1342         print_index_entry("\tpath: ", entry);
1343         */
1344         int clean_merge = 1;
1345         int normalize = o->renormalize;
1346         unsigned o_mode = entry->stages[1].mode;
1347         unsigned a_mode = entry->stages[2].mode;
1348         unsigned b_mode = entry->stages[3].mode;
1349         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1350         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1351         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1352
1353         if (entry->rename_df_conflict_info)
1354                 return 1; /* Such cases are handled elsewhere. */
1355
1356         entry->processed = 1;
1357         if (o_sha && (!a_sha || !b_sha)) {
1358                 /* Case A: Deleted in one */
1359                 if ((!a_sha && !b_sha) ||
1360                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1361                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1362                         /* Deleted in both or deleted in one and
1363                          * unchanged in the other */
1364                         if (a_sha)
1365                                 output(o, 2, "Removing %s", path);
1366                         /* do not touch working file if it did not exist */
1367                         remove_file(o, 1, path, !a_sha);
1368                 } else if (dir_in_way(path, 0 /*check_wc*/)) {
1369                         entry->processed = 0;
1370                         return 1; /* Assume clean until processed */
1371                 } else {
1372                         /* Deleted in one and changed in the other */
1373                         clean_merge = 0;
1374                         handle_delete_modify(o, path, path,
1375                                              a_sha, a_mode, b_sha, b_mode);
1376                 }
1377
1378         } else if ((!o_sha && a_sha && !b_sha) ||
1379                    (!o_sha && !a_sha && b_sha)) {
1380                 /* Case B: Added in one. */
1381                 unsigned mode;
1382                 const unsigned char *sha;
1383
1384                 if (a_sha) {
1385                         mode = a_mode;
1386                         sha = a_sha;
1387                 } else {
1388                         mode = b_mode;
1389                         sha = b_sha;
1390                 }
1391                 if (dir_in_way(path, 0 /*check_wc*/)) {
1392                         /* Handle D->F conflicts after all subfiles */
1393                         entry->processed = 0;
1394                         return 1; /* Assume clean until processed */
1395                 } else {
1396                         output(o, 2, "Adding %s", path);
1397                         update_file(o, 1, sha, mode, path);
1398                 }
1399         } else if (a_sha && b_sha) {
1400                 /* Case C: Added in both (check for same permissions) and */
1401                 /* case D: Modified in both, but differently. */
1402                 clean_merge = merge_content(o, path,
1403                                             o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1404                                             NULL);
1405         } else if (!o_sha && !a_sha && !b_sha) {
1406                 /*
1407                  * this entry was deleted altogether. a_mode == 0 means
1408                  * we had that path and want to actively remove it.
1409                  */
1410                 remove_file(o, 1, path, !a_mode);
1411         } else
1412                 die("Fatal merge failure, shouldn't happen.");
1413
1414         return clean_merge;
1415 }
1416
1417 /*
1418  * Per entry merge function for D/F (and/or rename) conflicts.  In the
1419  * cases we can cleanly resolve D/F conflicts, process_entry() can
1420  * clean out all the files below the directory for us.  All D/F
1421  * conflict cases must be handled here at the end to make sure any
1422  * directories that can be cleaned out, are.
1423  *
1424  * Some rename conflicts may also be handled here that don't necessarily
1425  * involve D/F conflicts, since the code to handle them is generic enough
1426  * to handle those rename conflicts with or without D/F conflicts also
1427  * being involved.
1428  */
1429 static int process_df_entry(struct merge_options *o,
1430                             const char *path, struct stage_data *entry)
1431 {
1432         int clean_merge = 1;
1433         unsigned o_mode = entry->stages[1].mode;
1434         unsigned a_mode = entry->stages[2].mode;
1435         unsigned b_mode = entry->stages[3].mode;
1436         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1437         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1438         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1439
1440         entry->processed = 1;
1441         if (entry->rename_df_conflict_info) {
1442                 struct rename_df_conflict_info *conflict_info = entry->rename_df_conflict_info;
1443                 char *src;
1444                 switch (conflict_info->rename_type) {
1445                 case RENAME_NORMAL:
1446                         clean_merge = merge_content(o, path,
1447                                                     o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1448                                                     conflict_info->branch1);
1449                         break;
1450                 case RENAME_DELETE:
1451                         clean_merge = 0;
1452                         conflict_rename_delete(o, conflict_info->pair1,
1453                                                conflict_info->branch1,
1454                                                conflict_info->branch2);
1455                         break;
1456                 case RENAME_ONE_FILE_TO_TWO:
1457                         src = conflict_info->pair1->one->path;
1458                         clean_merge = 0;
1459                         output(o, 1, "CONFLICT (rename/rename): "
1460                                "Rename \"%s\"->\"%s\" in branch \"%s\" "
1461                                "rename \"%s\"->\"%s\" in \"%s\"%s",
1462                                src, conflict_info->pair1->two->path, conflict_info->branch1,
1463                                src, conflict_info->pair2->two->path, conflict_info->branch2,
1464                                o->call_depth ? " (left unresolved)" : "");
1465                         if (o->call_depth) {
1466                                 remove_file_from_cache(src);
1467                                 update_file(o, 0, conflict_info->pair1->one->sha1,
1468                                             conflict_info->pair1->one->mode, src);
1469                         }
1470                         conflict_rename_rename_1to2(o, conflict_info->pair1,
1471                                                     conflict_info->branch1,
1472                                                     conflict_info->pair2,
1473                                                     conflict_info->branch2);
1474                         conflict_info->dst_entry2->processed = 1;
1475                         break;
1476                 default:
1477                         entry->processed = 0;
1478                         break;
1479                 }
1480         } else if (o_sha && (!a_sha || !b_sha)) {
1481                 /* Modify/delete; deleted side may have put a directory in the way */
1482                 char *renamed = NULL;
1483                 if (dir_in_way(path, !o->call_depth)) {
1484                         renamed = unique_path(o, path, a_sha ? o->branch1 : o->branch2);
1485                 }
1486                 clean_merge = 0;
1487                 handle_delete_modify(o, path, renamed ? renamed : path,
1488                                      a_sha, a_mode, b_sha, b_mode);
1489                 free(renamed);
1490         } else if (!o_sha && !!a_sha != !!b_sha) {
1491                 /* directory -> (directory, file) or <nothing> -> (directory, file) */
1492                 const char *add_branch;
1493                 const char *other_branch;
1494                 unsigned mode;
1495                 const unsigned char *sha;
1496                 const char *conf;
1497
1498                 if (a_sha) {
1499                         add_branch = o->branch1;
1500                         other_branch = o->branch2;
1501                         mode = a_mode;
1502                         sha = a_sha;
1503                         conf = "file/directory";
1504                 } else {
1505                         add_branch = o->branch2;
1506                         other_branch = o->branch1;
1507                         mode = b_mode;
1508                         sha = b_sha;
1509                         conf = "directory/file";
1510                 }
1511                 if (dir_in_way(path, !o->call_depth)) {
1512                         char *new_path = unique_path(o, path, add_branch);
1513                         clean_merge = 0;
1514                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1515                                "Adding %s as %s",
1516                                conf, path, other_branch, path, new_path);
1517                         update_file(o, 0, sha, mode, new_path);
1518                         if (o->call_depth)
1519                                 remove_file_from_cache(path);
1520                         free(new_path);
1521                 } else {
1522                         output(o, 2, "Adding %s", path);
1523                         update_file(o, 1, sha, mode, path);
1524                 }
1525         } else {
1526                 entry->processed = 0;
1527                 return 1; /* not handled; assume clean until processed */
1528         }
1529
1530         return clean_merge;
1531 }
1532
1533 int merge_trees(struct merge_options *o,
1534                 struct tree *head,
1535                 struct tree *merge,
1536                 struct tree *common,
1537                 struct tree **result)
1538 {
1539         int code, clean;
1540
1541         if (o->subtree_shift) {
1542                 merge = shift_tree_object(head, merge, o->subtree_shift);
1543                 common = shift_tree_object(head, common, o->subtree_shift);
1544         }
1545
1546         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1547                 output(o, 0, "Already up-to-date!");
1548                 *result = head;
1549                 return 1;
1550         }
1551
1552         code = git_merge_trees(o->call_depth, common, head, merge);
1553
1554         if (code != 0) {
1555                 if (show(o, 4) || o->call_depth)
1556                         die("merging of trees %s and %s failed",
1557                             sha1_to_hex(head->object.sha1),
1558                             sha1_to_hex(merge->object.sha1));
1559                 else
1560                         exit(128);
1561         }
1562
1563         if (unmerged_cache()) {
1564                 struct string_list *entries, *re_head, *re_merge;
1565                 int i;
1566                 string_list_clear(&o->current_file_set, 1);
1567                 string_list_clear(&o->current_directory_set, 1);
1568                 get_files_dirs(o, head);
1569                 get_files_dirs(o, merge);
1570
1571                 entries = get_unmerged();
1572                 make_room_for_directories_of_df_conflicts(o, entries);
1573                 re_head  = get_renames(o, head, common, head, merge, entries);
1574                 re_merge = get_renames(o, merge, common, head, merge, entries);
1575                 clean = process_renames(o, re_head, re_merge);
1576                 for (i = 0; i < entries->nr; i++) {
1577                         const char *path = entries->items[i].string;
1578                         struct stage_data *e = entries->items[i].util;
1579                         if (!e->processed
1580                                 && !process_entry(o, path, e))
1581                                 clean = 0;
1582                 }
1583                 for (i = 0; i < entries->nr; i++) {
1584                         const char *path = entries->items[i].string;
1585                         struct stage_data *e = entries->items[i].util;
1586                         if (!e->processed
1587                                 && !process_df_entry(o, path, e))
1588                                 clean = 0;
1589                 }
1590                 for (i = 0; i < entries->nr; i++) {
1591                         struct stage_data *e = entries->items[i].util;
1592                         if (!e->processed)
1593                                 die("Unprocessed path??? %s",
1594                                     entries->items[i].string);
1595                 }
1596
1597                 string_list_clear(re_merge, 0);
1598                 string_list_clear(re_head, 0);
1599                 string_list_clear(entries, 1);
1600
1601         }
1602         else
1603                 clean = 1;
1604
1605         if (o->call_depth)
1606                 *result = write_tree_from_memory(o);
1607
1608         return clean;
1609 }
1610
1611 static struct commit_list *reverse_commit_list(struct commit_list *list)
1612 {
1613         struct commit_list *next = NULL, *current, *backup;
1614         for (current = list; current; current = backup) {
1615                 backup = current->next;
1616                 current->next = next;
1617                 next = current;
1618         }
1619         return next;
1620 }
1621
1622 /*
1623  * Merge the commits h1 and h2, return the resulting virtual
1624  * commit object and a flag indicating the cleanness of the merge.
1625  */
1626 int merge_recursive(struct merge_options *o,
1627                     struct commit *h1,
1628                     struct commit *h2,
1629                     struct commit_list *ca,
1630                     struct commit **result)
1631 {
1632         struct commit_list *iter;
1633         struct commit *merged_common_ancestors;
1634         struct tree *mrtree = mrtree;
1635         int clean;
1636
1637         if (show(o, 4)) {
1638                 output(o, 4, "Merging:");
1639                 output_commit_title(o, h1);
1640                 output_commit_title(o, h2);
1641         }
1642
1643         if (!ca) {
1644                 ca = get_merge_bases(h1, h2, 1);
1645                 ca = reverse_commit_list(ca);
1646         }
1647
1648         if (show(o, 5)) {
1649                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1650                 for (iter = ca; iter; iter = iter->next)
1651                         output_commit_title(o, iter->item);
1652         }
1653
1654         merged_common_ancestors = pop_commit(&ca);
1655         if (merged_common_ancestors == NULL) {
1656                 /* if there is no common ancestor, make an empty tree */
1657                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1658
1659                 tree->object.parsed = 1;
1660                 tree->object.type = OBJ_TREE;
1661                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1662                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1663         }
1664
1665         for (iter = ca; iter; iter = iter->next) {
1666                 const char *saved_b1, *saved_b2;
1667                 o->call_depth++;
1668                 /*
1669                  * When the merge fails, the result contains files
1670                  * with conflict markers. The cleanness flag is
1671                  * ignored, it was never actually used, as result of
1672                  * merge_trees has always overwritten it: the committed
1673                  * "conflicts" were already resolved.
1674                  */
1675                 discard_cache();
1676                 saved_b1 = o->branch1;
1677                 saved_b2 = o->branch2;
1678                 o->branch1 = "Temporary merge branch 1";
1679                 o->branch2 = "Temporary merge branch 2";
1680                 merge_recursive(o, merged_common_ancestors, iter->item,
1681                                 NULL, &merged_common_ancestors);
1682                 o->branch1 = saved_b1;
1683                 o->branch2 = saved_b2;
1684                 o->call_depth--;
1685
1686                 if (!merged_common_ancestors)
1687                         die("merge returned no commit");
1688         }
1689
1690         discard_cache();
1691         if (!o->call_depth)
1692                 read_cache();
1693
1694         o->ancestor = "merged common ancestors";
1695         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1696                             &mrtree);
1697
1698         if (o->call_depth) {
1699                 *result = make_virtual_commit(mrtree, "merged tree");
1700                 commit_list_insert(h1, &(*result)->parents);
1701                 commit_list_insert(h2, &(*result)->parents->next);
1702         }
1703         flush_output(o);
1704         if (show(o, 2))
1705                 diff_warn_rename_limit("merge.renamelimit",
1706                                        o->needed_rename_limit, 0);
1707         return clean;
1708 }
1709
1710 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1711 {
1712         struct object *object;
1713
1714         object = deref_tag(parse_object(sha1), name, strlen(name));
1715         if (!object)
1716                 return NULL;
1717         if (object->type == OBJ_TREE)
1718                 return make_virtual_commit((struct tree*)object, name);
1719         if (object->type != OBJ_COMMIT)
1720                 return NULL;
1721         if (parse_commit((struct commit *)object))
1722                 return NULL;
1723         return (struct commit *)object;
1724 }
1725
1726 int merge_recursive_generic(struct merge_options *o,
1727                             const unsigned char *head,
1728                             const unsigned char *merge,
1729                             int num_base_list,
1730                             const unsigned char **base_list,
1731                             struct commit **result)
1732 {
1733         int clean, index_fd;
1734         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1735         struct commit *head_commit = get_ref(head, o->branch1);
1736         struct commit *next_commit = get_ref(merge, o->branch2);
1737         struct commit_list *ca = NULL;
1738
1739         if (base_list) {
1740                 int i;
1741                 for (i = 0; i < num_base_list; ++i) {
1742                         struct commit *base;
1743                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1744                                 return error("Could not parse object '%s'",
1745                                         sha1_to_hex(base_list[i]));
1746                         commit_list_insert(base, &ca);
1747                 }
1748         }
1749
1750         index_fd = hold_locked_index(lock, 1);
1751         clean = merge_recursive(o, head_commit, next_commit, ca,
1752                         result);
1753         if (active_cache_changed &&
1754                         (write_cache(index_fd, active_cache, active_nr) ||
1755                          commit_locked_index(lock)))
1756                 return error("Unable to write index.");
1757
1758         return clean ? 0 : 1;
1759 }
1760
1761 static int merge_recursive_config(const char *var, const char *value, void *cb)
1762 {
1763         struct merge_options *o = cb;
1764         if (!strcmp(var, "merge.verbosity")) {
1765                 o->verbosity = git_config_int(var, value);
1766                 return 0;
1767         }
1768         if (!strcmp(var, "diff.renamelimit")) {
1769                 o->diff_rename_limit = git_config_int(var, value);
1770                 return 0;
1771         }
1772         if (!strcmp(var, "merge.renamelimit")) {
1773                 o->merge_rename_limit = git_config_int(var, value);
1774                 return 0;
1775         }
1776         return git_xmerge_config(var, value, cb);
1777 }
1778
1779 void init_merge_options(struct merge_options *o)
1780 {
1781         memset(o, 0, sizeof(struct merge_options));
1782         o->verbosity = 2;
1783         o->buffer_output = 1;
1784         o->diff_rename_limit = -1;
1785         o->merge_rename_limit = -1;
1786         o->renormalize = 0;
1787         git_config(merge_recursive_config, o);
1788         if (getenv("GIT_MERGE_VERBOSITY"))
1789                 o->verbosity =
1790                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1791         if (o->verbosity >= 5)
1792                 o->buffer_output = 0;
1793         strbuf_init(&o->obuf, 0);
1794         memset(&o->current_file_set, 0, sizeof(struct string_list));
1795         o->current_file_set.strdup_strings = 1;
1796         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1797         o->current_directory_set.strdup_strings = 1;
1798 }
1799
1800 int parse_merge_opt(struct merge_options *o, const char *s)
1801 {
1802         if (!s || !*s)
1803                 return -1;
1804         if (!strcmp(s, "ours"))
1805                 o->recursive_variant = MERGE_RECURSIVE_OURS;
1806         else if (!strcmp(s, "theirs"))
1807                 o->recursive_variant = MERGE_RECURSIVE_THEIRS;
1808         else if (!strcmp(s, "subtree"))
1809                 o->subtree_shift = "";
1810         else if (!prefixcmp(s, "subtree="))
1811                 o->subtree_shift = s + strlen("subtree=");
1812         else if (!strcmp(s, "patience"))
1813                 o->xdl_opts |= XDF_PATIENCE_DIFF;
1814         else if (!strcmp(s, "ignore-space-change"))
1815                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
1816         else if (!strcmp(s, "ignore-all-space"))
1817                 o->xdl_opts |= XDF_IGNORE_WHITESPACE;
1818         else if (!strcmp(s, "ignore-space-at-eol"))
1819                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
1820         else if (!strcmp(s, "renormalize"))
1821                 o->renormalize = 1;
1822         else if (!strcmp(s, "no-renormalize"))
1823                 o->renormalize = 0;
1824         else if (!prefixcmp(s, "rename-threshold=")) {
1825                 const char *score = s + strlen("rename-threshold=");
1826                 if ((o->rename_score = parse_rename_score(&score)) == -1 || *score != 0)
1827                         return -1;
1828         }
1829         else
1830                 return -1;
1831         return 0;
1832 }