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