merge-recursive.c

   1 /*
   2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
   3  * Fredrik Kuivinen.
   4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
   5  */
   6 #include "cache.h"
   7 #include "cache-tree.h"
   8 #include "commit.h"
   9 #include "blob.h"
  10 #include "tree-walk.h"
  11 #include "diff.h"
  12 #include "diffcore.h"
  13 #include "run-command.h"
  14 #include "tag.h"
  15 #include "unpack-trees.h"
  16 #include "path-list.h"
  17 #include "xdiff-interface.h"
  18 #include "interpolate.h"
  19 #include "attr.h"
  20
  21 static int subtree_merge;
  22
  23 static struct tree *shift_tree_object(struct tree *one, struct tree *two)
  24 {
  25         unsigned char shifted[20];
  26
  27         /*
  28          * NEEDSWORK: this limits the recursion depth to hardcoded
  29          * value '2' to avoid excessive overhead.
  30          */
  31         shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
  32         if (!hashcmp(two->object.sha1, shifted))
  33                 return two;
  34         return lookup_tree(shifted);
  35 }
  36
  37 /*
  38  * A virtual commit has
  39  * - (const char *)commit->util set to the name, and
  40  * - *(int *)commit->object.sha1 set to the virtual id.
  41  */
  42
  43 static unsigned commit_list_count(const struct commit_list *l)
  44 {
  45         unsigned c = 0;
  46         for (; l; l = l->next )
  47                 c++;
  48         return c;
  49 }
  50
  51 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  52 {
  53         struct commit *commit = xcalloc(1, sizeof(struct commit));
  54         static unsigned virtual_id = 1;
  55         commit->tree = tree;
  56         commit->util = (void*)comment;
  57         *(int*)commit->object.sha1 = virtual_id++;
  58         /* avoid warnings */
  59         commit->object.parsed = 1;
  60         return commit;
  61 }
  62
  63 /*
  64  * Since we use get_tree_entry(), which does not put the read object into
  65  * the object pool, we cannot rely on a == b.
  66  */
  67 static int sha_eq(const unsigned char *a, const unsigned char *b)
  68 {
  69         if (!a && !b)
  70                 return 2;
  71         return a && b && hashcmp(a, b) == 0;
  72 }
  73
  74 /*
  75  * Since we want to write the index eventually, we cannot reuse the index
  76  * for these (temporary) data.
  77  */
  78 struct stage_data
  79 {
  80         struct
  81         {
  82                 unsigned mode;
  83                 unsigned char sha[20];
  84         } stages[4];
  85         unsigned processed:1;
  86 };
  87
  88 static struct path_list current_file_set = {NULL, 0, 0, 1};
  89 static struct path_list current_directory_set = {NULL, 0, 0, 1};
  90
  91 static int call_depth = 0;
  92 static int verbosity = 2;
  93 static int buffer_output = 1;
  94 static struct strbuf obuf = STRBUF_INIT;
  95
  96 static int show(int v)
  97 {
  98         return (!call_depth && verbosity >= v) || verbosity >= 5;
  99 }
 100
 101 static void flush_output(void)
 102 {
 103         if (obuf.len) {
 104                 fputs(obuf.buf, stdout);
 105                 strbuf_reset(&obuf);
 106         }
 107 }
 108
 109 static void output(int v, const char *fmt, ...)
 110 {
 111         int len;
 112         va_list ap;
 113
 114         if (!show(v))
 115                 return;
 116
 117         strbuf_grow(&obuf, call_depth * 2 + 2);
 118         memset(obuf.buf + obuf.len, ' ', call_depth * 2);
 119         strbuf_setlen(&obuf, obuf.len + call_depth * 2);
 120
 121         va_start(ap, fmt);
 122         len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
 123         va_end(ap);
 124
 125         if (len < 0)
 126                 len = 0;
 127         if (len >= strbuf_avail(&obuf)) {
 128                 strbuf_grow(&obuf, len + 2);
 129                 va_start(ap, fmt);
 130                 len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
 131                 va_end(ap);
 132                 if (len >= strbuf_avail(&obuf)) {
 133                         die("this should not happen, your snprintf is broken");
 134                 }
 135         }
 136         strbuf_setlen(&obuf, obuf.len + len);
 137         strbuf_add(&obuf, "\n", 1);
 138         if (!buffer_output)
 139                 flush_output();
 140 }
 141
 142 static void output_commit_title(struct commit *commit)
 143 {
 144         int i;
 145         flush_output();
 146         for (i = call_depth; i--;)
 147                 fputs("  ", stdout);
 148         if (commit->util)
 149                 printf("virtual %s\n", (char *)commit->util);
 150         else {
 151                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 152                 if (parse_commit(commit) != 0)
 153                         printf("(bad commit)\n");
 154                 else {
 155                         const char *s;
 156                         int len;
 157                         for (s = commit->buffer; *s; s++)
 158                                 if (*s == '\n' && s[1] == '\n') {
 159                                         s += 2;
 160                                         break;
 161                                 }
 162                         for (len = 0; s[len] && '\n' != s[len]; len++)
 163                                 ; /* do nothing */
 164                         printf("%.*s\n", len, s);
 165                 }
 166         }
 167 }
 168
 169 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 170                 const char *path, int stage, int refresh, int options)
 171 {
 172         struct cache_entry *ce;
 173         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 174         if (!ce)
 175                 return error("addinfo_cache failed for path '%s'", path);
 176         return add_cache_entry(ce, options);
 177 }
 178
 179 /*
 180  * This is a global variable which is used in a number of places but
 181  * only written to in the 'merge' function.
 182  *
 183  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
 184  *                       don't update the working directory.
 185  *               0    => Leave unmerged entries in the cache and update
 186  *                       the working directory.
 187  */
 188 static int index_only = 0;
 189
 190 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 191 {
 192         parse_tree(tree);
 193         init_tree_desc(desc, tree->buffer, tree->size);
 194 }
 195
 196 static int git_merge_trees(int index_only,
 197                            struct tree *common,
 198                            struct tree *head,
 199                            struct tree *merge)
 200 {
 201         int rc;
 202         struct tree_desc t[3];
 203         struct unpack_trees_options opts;
 204
 205         memset(&opts, 0, sizeof(opts));
 206         if (index_only)
 207                 opts.index_only = 1;
 208         else
 209                 opts.update = 1;
 210         opts.merge = 1;
 211         opts.head_idx = 2;
 212         opts.fn = threeway_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 static int unmerged_index(void)
 224 {
 225         int i;
 226         for (i = 0; i < active_nr; i++) {
 227                 struct cache_entry *ce = active_cache[i];
 228                 if (ce_stage(ce))
 229                         return 1;
 230         }
 231         return 0;
 232 }
 233
 234 static struct tree *git_write_tree(void)
 235 {
 236         struct tree *result = NULL;
 237
 238         if (unmerged_index()) {
 239                 int i;
 240                 output(0, "There are unmerged index entries:");
 241                 for (i = 0; i < active_nr; i++) {
 242                         struct cache_entry *ce = active_cache[i];
 243                         if (ce_stage(ce))
 244                                 output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
 245                 }
 246                 return NULL;
 247         }
 248
 249         if (!active_cache_tree)
 250                 active_cache_tree = cache_tree();
 251
 252         if (!cache_tree_fully_valid(active_cache_tree) &&
 253             cache_tree_update(active_cache_tree,
 254                               active_cache, active_nr, 0, 0) < 0)
 255                 die("error building trees");
 256
 257         result = lookup_tree(active_cache_tree->sha1);
 258
 259         return result;
 260 }
 261
 262 static int save_files_dirs(const unsigned char *sha1,
 263                 const char *base, int baselen, const char *path,
 264                 unsigned int mode, int stage)
 265 {
 266         int len = strlen(path);
 267         char *newpath = xmalloc(baselen + len + 1);
 268         memcpy(newpath, base, baselen);
 269         memcpy(newpath + baselen, path, len);
 270         newpath[baselen + len] = '\0';
 271
 272         if (S_ISDIR(mode))
 273                 path_list_insert(newpath, &current_directory_set);
 274         else
 275                 path_list_insert(newpath, &current_file_set);
 276         free(newpath);
 277
 278         return READ_TREE_RECURSIVE;
 279 }
 280
 281 static int get_files_dirs(struct tree *tree)
 282 {
 283         int n;
 284         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
 285                 return 0;
 286         n = current_file_set.nr + current_directory_set.nr;
 287         return n;
 288 }
 289
 290 /*
 291  * Returns a index_entry instance which doesn't have to correspond to
 292  * a real cache entry in Git's index.
 293  */
 294 static struct stage_data *insert_stage_data(const char *path,
 295                 struct tree *o, struct tree *a, struct tree *b,
 296                 struct path_list *entries)
 297 {
 298         struct path_list_item *item;
 299         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 300         get_tree_entry(o->object.sha1, path,
 301                         e->stages[1].sha, &e->stages[1].mode);
 302         get_tree_entry(a->object.sha1, path,
 303                         e->stages[2].sha, &e->stages[2].mode);
 304         get_tree_entry(b->object.sha1, path,
 305                         e->stages[3].sha, &e->stages[3].mode);
 306         item = path_list_insert(path, entries);
 307         item->util = e;
 308         return e;
 309 }
 310
 311 /*
 312  * Create a dictionary mapping file names to stage_data objects. The
 313  * dictionary contains one entry for every path with a non-zero stage entry.
 314  */
 315 static struct path_list *get_unmerged(void)
 316 {
 317         struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
 318         int i;
 319
 320         unmerged->strdup_paths = 1;
 321
 322         for (i = 0; i < active_nr; i++) {
 323                 struct path_list_item *item;
 324                 struct stage_data *e;
 325                 struct cache_entry *ce = active_cache[i];
 326                 if (!ce_stage(ce))
 327                         continue;
 328
 329                 item = path_list_lookup(ce->name, unmerged);
 330                 if (!item) {
 331                         item = path_list_insert(ce->name, unmerged);
 332                         item->util = xcalloc(1, sizeof(struct stage_data));
 333                 }
 334                 e = item->util;
 335                 e->stages[ce_stage(ce)].mode = ntohl(ce->ce_mode);
 336                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 337         }
 338
 339         return unmerged;
 340 }
 341
 342 struct rename
 343 {
 344         struct diff_filepair *pair;
 345         struct stage_data *src_entry;
 346         struct stage_data *dst_entry;
 347         unsigned processed:1;
 348 };
 349
 350 /*
 351  * Get information of all renames which occurred between 'o_tree' and
 352  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 353  * 'b_tree') to be able to associate the correct cache entries with
 354  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 355  */
 356 static struct path_list *get_renames(struct tree *tree,
 357                                         struct tree *o_tree,
 358                                         struct tree *a_tree,
 359                                         struct tree *b_tree,
 360                                         struct path_list *entries)
 361 {
 362         int i;
 363         struct path_list *renames;
 364         struct diff_options opts;
 365
 366         renames = xcalloc(1, sizeof(struct path_list));
 367         diff_setup(&opts);
 368         opts.recursive = 1;
 369         opts.detect_rename = DIFF_DETECT_RENAME;
 370         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 371         if (diff_setup_done(&opts) < 0)
 372                 die("diff setup failed");
 373         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 374         diffcore_std(&opts);
 375         for (i = 0; i < diff_queued_diff.nr; ++i) {
 376                 struct path_list_item *item;
 377                 struct rename *re;
 378                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 379                 if (pair->status != 'R') {
 380                         diff_free_filepair(pair);
 381                         continue;
 382                 }
 383                 re = xmalloc(sizeof(*re));
 384                 re->processed = 0;
 385                 re->pair = pair;
 386                 item = path_list_lookup(re->pair->one->path, entries);
 387                 if (!item)
 388                         re->src_entry = insert_stage_data(re->pair->one->path,
 389                                         o_tree, a_tree, b_tree, entries);
 390                 else
 391                         re->src_entry = item->util;
 392
 393                 item = path_list_lookup(re->pair->two->path, entries);
 394                 if (!item)
 395                         re->dst_entry = insert_stage_data(re->pair->two->path,
 396                                         o_tree, a_tree, b_tree, entries);
 397                 else
 398                         re->dst_entry = item->util;
 399                 item = path_list_insert(pair->one->path, renames);
 400                 item->util = re;
 401         }
 402         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 403         diff_queued_diff.nr = 0;
 404         diff_flush(&opts);
 405         return renames;
 406 }
 407
 408 static int update_stages(const char *path, struct diff_filespec *o,
 409                          struct diff_filespec *a, struct diff_filespec *b,
 410                          int clear)
 411 {
 412         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 413         if (clear)
 414                 if (remove_file_from_cache(path))
 415                         return -1;
 416         if (o)
 417                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 418                         return -1;
 419         if (a)
 420                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 421                         return -1;
 422         if (b)
 423                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 424                         return -1;
 425         return 0;
 426 }
 427
 428 static int remove_path(const char *name)
 429 {
 430         int ret;
 431         char *slash, *dirs;
 432
 433         ret = unlink(name);
 434         if (ret)
 435                 return ret;
 436         dirs = xstrdup(name);
 437         while ((slash = strrchr(name, '/'))) {
 438                 *slash = '\0';
 439                 if (rmdir(name) != 0)
 440                         break;
 441         }
 442         free(dirs);
 443         return ret;
 444 }
 445
 446 static int remove_file(int clean, const char *path, int no_wd)
 447 {
 448         int update_cache = index_only || clean;
 449         int update_working_directory = !index_only && !no_wd;
 450
 451         if (update_cache) {
 452                 if (remove_file_from_cache(path))
 453                         return -1;
 454         }
 455         if (update_working_directory) {
 456                 unlink(path);
 457                 if (errno != ENOENT || errno != EISDIR)
 458                         return -1;
 459                 remove_path(path);
 460         }
 461         return 0;
 462 }
 463
 464 static char *unique_path(const char *path, const char *branch)
 465 {
 466         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 467         int suffix = 0;
 468         struct stat st;
 469         char *p = newpath + strlen(path);
 470         strcpy(newpath, path);
 471         *(p++) = '~';
 472         strcpy(p, branch);
 473         for (; *p; ++p)
 474                 if ('/' == *p)
 475                         *p = '_';
 476         while (path_list_has_path(&current_file_set, newpath) ||
 477                path_list_has_path(&current_directory_set, newpath) ||
 478                lstat(newpath, &st) == 0)
 479                 sprintf(p, "_%d", suffix++);
 480
 481         path_list_insert(newpath, &current_file_set);
 482         return newpath;
 483 }
 484
 485 static int mkdir_p(const char *path, unsigned long mode)
 486 {
 487         /* path points to cache entries, so xstrdup before messing with it */
 488         char *buf = xstrdup(path);
 489         int result = safe_create_leading_directories(buf);
 490         free(buf);
 491         return result;
 492 }
 493
 494 static void flush_buffer(int fd, const char *buf, unsigned long size)
 495 {
 496         while (size > 0) {
 497                 long ret = write_in_full(fd, buf, size);
 498                 if (ret < 0) {
 499                         /* Ignore epipe */
 500                         if (errno == EPIPE)
 501                                 break;
 502                         die("merge-recursive: %s", strerror(errno));
 503                 } else if (!ret) {
 504                         die("merge-recursive: disk full?");
 505                 }
 506                 size -= ret;
 507                 buf += ret;
 508         }
 509 }
 510
 511 static int make_room_for_path(const char *path)
 512 {
 513         int status;
 514         const char *msg = "failed to create path '%s'%s";
 515
 516         status = mkdir_p(path, 0777);
 517         if (status) {
 518                 if (status == -3) {
 519                         /* something else exists */
 520                         error(msg, path, ": perhaps a D/F conflict?");
 521                         return -1;
 522                 }
 523                 die(msg, path, "");
 524         }
 525
 526         /* Successful unlink is good.. */
 527         if (!unlink(path))
 528                 return 0;
 529         /* .. and so is no existing file */
 530         if (errno == ENOENT)
 531                 return 0;
 532         /* .. but not some other error (who really cares what?) */
 533         return error(msg, path, ": perhaps a D/F conflict?");
 534 }
 535
 536 static void update_file_flags(const unsigned char *sha,
 537                               unsigned mode,
 538                               const char *path,
 539                               int update_cache,
 540                               int update_wd)
 541 {
 542         if (index_only)
 543                 update_wd = 0;
 544
 545         if (update_wd) {
 546                 enum object_type type;
 547                 void *buf;
 548                 unsigned long size;
 549
 550                 buf = read_sha1_file(sha, &type, &size);
 551                 if (!buf)
 552                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 553                 if (type != OBJ_BLOB)
 554                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 555
 556                 if (make_room_for_path(path) < 0) {
 557                         update_wd = 0;
 558                         goto update_index;
 559                 }
 560                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 561                         int fd;
 562                         if (mode & 0100)
 563                                 mode = 0777;
 564                         else
 565                                 mode = 0666;
 566                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 567                         if (fd < 0)
 568                                 die("failed to open %s: %s", path, strerror(errno));
 569                         flush_buffer(fd, buf, size);
 570                         close(fd);
 571                 } else if (S_ISLNK(mode)) {
 572                         char *lnk = xmemdupz(buf, size);
 573                         mkdir_p(path, 0777);
 574                         unlink(path);
 575                         symlink(lnk, path);
 576                         free(lnk);
 577                 } else
 578                         die("do not know what to do with %06o %s '%s'",
 579                             mode, sha1_to_hex(sha), path);
 580         }
 581  update_index:
 582         if (update_cache)
 583                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 584 }
 585
 586 static void update_file(int clean,
 587                         const unsigned char *sha,
 588                         unsigned mode,
 589                         const char *path)
 590 {
 591         update_file_flags(sha, mode, path, index_only || clean, !index_only);
 592 }
 593
 594 /* Low level file merging, update and removal */
 595
 596 struct merge_file_info
 597 {
 598         unsigned char sha[20];
 599         unsigned mode;
 600         unsigned clean:1,
 601                  merge:1;
 602 };
 603
 604 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 605 {
 606         unsigned long size;
 607         enum object_type type;
 608
 609         if (!hashcmp(sha1, null_sha1)) {
 610                 mm->ptr = xstrdup("");
 611                 mm->size = 0;
 612                 return;
 613         }
 614
 615         mm->ptr = read_sha1_file(sha1, &type, &size);
 616         if (!mm->ptr || type != OBJ_BLOB)
 617                 die("unable to read blob object %s", sha1_to_hex(sha1));
 618         mm->size = size;
 619 }
 620
 621 /*
 622  * Customizable low-level merge drivers support.
 623  */
 624
 625 struct ll_merge_driver;
 626 typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
 627                            const char *path,
 628                            mmfile_t *orig,
 629                            mmfile_t *src1, const char *name1,
 630                            mmfile_t *src2, const char *name2,
 631                            mmbuffer_t *result);
 632
 633 struct ll_merge_driver {
 634         const char *name;
 635         const char *description;
 636         ll_merge_fn fn;
 637         const char *recursive;
 638         struct ll_merge_driver *next;
 639         char *cmdline;
 640 };
 641
 642 /*
 643  * Built-in low-levels
 644  */
 645 static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
 646                            const char *path_unused,
 647                            mmfile_t *orig,
 648                            mmfile_t *src1, const char *name1,
 649                            mmfile_t *src2, const char *name2,
 650                            mmbuffer_t *result)
 651 {
 652         /*
 653          * The tentative merge result is "ours" for the final round,
 654          * or common ancestor for an internal merge.  Still return
 655          * "conflicted merge" status.
 656          */
 657         mmfile_t *stolen = index_only ? orig : src1;
 658
 659         result->ptr = stolen->ptr;
 660         result->size = stolen->size;
 661         stolen->ptr = NULL;
 662         return 1;
 663 }
 664
 665 static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
 666                         const char *path_unused,
 667                         mmfile_t *orig,
 668                         mmfile_t *src1, const char *name1,
 669                         mmfile_t *src2, const char *name2,
 670                         mmbuffer_t *result)
 671 {
 672         xpparam_t xpp;
 673
 674         if (buffer_is_binary(orig->ptr, orig->size) ||
 675             buffer_is_binary(src1->ptr, src1->size) ||
 676             buffer_is_binary(src2->ptr, src2->size)) {
 677                 warning("Cannot merge binary files: %s vs. %s\n",
 678                         name1, name2);
 679                 return ll_binary_merge(drv_unused, path_unused,
 680                                        orig, src1, name1,
 681                                        src2, name2,
 682                                        result);
 683         }
 684
 685         memset(&xpp, 0, sizeof(xpp));
 686         return xdl_merge(orig,
 687                          src1, name1,
 688                          src2, name2,
 689                          &xpp, XDL_MERGE_ZEALOUS,
 690                          result);
 691 }
 692
 693 static int ll_union_merge(const struct ll_merge_driver *drv_unused,
 694                           const char *path_unused,
 695                           mmfile_t *orig,
 696                           mmfile_t *src1, const char *name1,
 697                           mmfile_t *src2, const char *name2,
 698                           mmbuffer_t *result)
 699 {
 700         char *src, *dst;
 701         long size;
 702         const int marker_size = 7;
 703
 704         int status = ll_xdl_merge(drv_unused, path_unused,
 705                                   orig, src1, NULL, src2, NULL, result);
 706         if (status <= 0)
 707                 return status;
 708         size = result->size;
 709         src = dst = result->ptr;
 710         while (size) {
 711                 char ch;
 712                 if ((marker_size < size) &&
 713                     (*src == '<' || *src == '=' || *src == '>')) {
 714                         int i;
 715                         ch = *src;
 716                         for (i = 0; i < marker_size; i++)
 717                                 if (src[i] != ch)
 718                                         goto not_a_marker;
 719                         if (src[marker_size] != '\n')
 720                                 goto not_a_marker;
 721                         src += marker_size + 1;
 722                         size -= marker_size + 1;
 723                         continue;
 724                 }
 725         not_a_marker:
 726                 do {
 727                         ch = *src++;
 728                         *dst++ = ch;
 729                         size--;
 730                 } while (ch != '\n' && size);
 731         }
 732         result->size = dst - result->ptr;
 733         return 0;
 734 }
 735
 736 #define LL_BINARY_MERGE 0
 737 #define LL_TEXT_MERGE 1
 738 #define LL_UNION_MERGE 2
 739 static struct ll_merge_driver ll_merge_drv[] = {
 740         { "binary", "built-in binary merge", ll_binary_merge },
 741         { "text", "built-in 3-way text merge", ll_xdl_merge },
 742         { "union", "built-in union merge", ll_union_merge },
 743 };
 744
 745 static void create_temp(mmfile_t *src, char *path)
 746 {
 747         int fd;
 748
 749         strcpy(path, ".merge_file_XXXXXX");
 750         fd = xmkstemp(path);
 751         if (write_in_full(fd, src->ptr, src->size) != src->size)
 752                 die("unable to write temp-file");
 753         close(fd);
 754 }
 755
 756 /*
 757  * User defined low-level merge driver support.
 758  */
 759 static int ll_ext_merge(const struct ll_merge_driver *fn,
 760                         const char *path,
 761                         mmfile_t *orig,
 762                         mmfile_t *src1, const char *name1,
 763                         mmfile_t *src2, const char *name2,
 764                         mmbuffer_t *result)
 765 {
 766         char temp[3][50];
 767         char cmdbuf[2048];
 768         struct interp table[] = {
 769                 { "%O" },
 770                 { "%A" },
 771                 { "%B" },
 772         };
 773         struct child_process child;
 774         const char *args[20];
 775         int status, fd, i;
 776         struct stat st;
 777
 778         if (fn->cmdline == NULL)
 779                 die("custom merge driver %s lacks command line.", fn->name);
 780
 781         result->ptr = NULL;
 782         result->size = 0;
 783         create_temp(orig, temp[0]);
 784         create_temp(src1, temp[1]);
 785         create_temp(src2, temp[2]);
 786
 787         interp_set_entry(table, 0, temp[0]);
 788         interp_set_entry(table, 1, temp[1]);
 789         interp_set_entry(table, 2, temp[2]);
 790
 791         output(1, "merging %s using %s", path,
 792                fn->description ? fn->description : fn->name);
 793
 794         interpolate(cmdbuf, sizeof(cmdbuf), fn->cmdline, table, 3);
 795
 796         memset(&child, 0, sizeof(child));
 797         child.argv = args;
 798         args[0] = "sh";
 799         args[1] = "-c";
 800         args[2] = cmdbuf;
 801         args[3] = NULL;
 802
 803         status = run_command(&child);
 804         if (status < -ERR_RUN_COMMAND_FORK)
 805                 ; /* failure in run-command */
 806         else
 807                 status = -status;
 808         fd = open(temp[1], O_RDONLY);
 809         if (fd < 0)
 810                 goto bad;
 811         if (fstat(fd, &st))
 812                 goto close_bad;
 813         result->size = st.st_size;
 814         result->ptr = xmalloc(result->size + 1);
 815         if (read_in_full(fd, result->ptr, result->size) != result->size) {
 816                 free(result->ptr);
 817                 result->ptr = NULL;
 818                 result->size = 0;
 819         }
 820  close_bad:
 821         close(fd);
 822  bad:
 823         for (i = 0; i < 3; i++)
 824                 unlink(temp[i]);
 825         return status;
 826 }
 827
 828 /*
 829  * merge.default and merge.driver configuration items
 830  */
 831 static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
 832 static const char *default_ll_merge;
 833
 834 static int read_merge_config(const char *var, const char *value)
 835 {
 836         struct ll_merge_driver *fn;
 837         const char *ep, *name;
 838         int namelen;
 839
 840         if (!strcmp(var, "merge.default")) {
 841                 if (value)
 842                         default_ll_merge = strdup(value);
 843                 return 0;
 844         }
 845
 846         /*
 847          * We are not interested in anything but "merge.<name>.variable";
 848          * especially, we do not want to look at variables such as
 849          * "merge.summary", "merge.tool", and "merge.verbosity".
 850          */
 851         if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
 852                 return 0;
 853
 854         /*
 855          * Find existing one as we might be processing merge.<name>.var2
 856          * after seeing merge.<name>.var1.
 857          */
 858         name = var + 6;
 859         namelen = ep - name;
 860         for (fn = ll_user_merge; fn; fn = fn->next)
 861                 if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
 862                         break;
 863         if (!fn) {
 864                 fn = xcalloc(1, sizeof(struct ll_merge_driver));
 865                 fn->name = xmemdupz(name, namelen);
 866                 fn->fn = ll_ext_merge;
 867                 *ll_user_merge_tail = fn;
 868                 ll_user_merge_tail = &(fn->next);
 869         }
 870
 871         ep++;
 872
 873         if (!strcmp("name", ep)) {
 874                 if (!value)
 875                         return error("%s: lacks value", var);
 876                 fn->description = strdup(value);
 877                 return 0;
 878         }
 879
 880         if (!strcmp("driver", ep)) {
 881                 if (!value)
 882                         return error("%s: lacks value", var);
 883                 /*
 884                  * merge.<name>.driver specifies the command line:
 885                  *
 886                  *      command-line
 887                  *
 888                  * The command-line will be interpolated with the following
 889                  * tokens and is given to the shell:
 890                  *
 891                  *    %O - temporary file name for the merge base.
 892                  *    %A - temporary file name for our version.
 893                  *    %B - temporary file name for the other branches' version.
 894                  *
 895                  * The external merge driver should write the results in the
 896                  * file named by %A, and signal that it has done with zero exit
 897                  * status.
 898                  */
 899                 fn->cmdline = strdup(value);
 900                 return 0;
 901         }
 902
 903         if (!strcmp("recursive", ep)) {
 904                 if (!value)
 905                         return error("%s: lacks value", var);
 906                 fn->recursive = strdup(value);
 907                 return 0;
 908         }
 909
 910         return 0;
 911 }
 912
 913 static void initialize_ll_merge(void)
 914 {
 915         if (ll_user_merge_tail)
 916                 return;
 917         ll_user_merge_tail = &ll_user_merge;
 918         git_config(read_merge_config);
 919 }
 920
 921 static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
 922 {
 923         struct ll_merge_driver *fn;
 924         const char *name;
 925         int i;
 926
 927         initialize_ll_merge();
 928
 929         if (ATTR_TRUE(merge_attr))
 930                 return &ll_merge_drv[LL_TEXT_MERGE];
 931         else if (ATTR_FALSE(merge_attr))
 932                 return &ll_merge_drv[LL_BINARY_MERGE];
 933         else if (ATTR_UNSET(merge_attr)) {
 934                 if (!default_ll_merge)
 935                         return &ll_merge_drv[LL_TEXT_MERGE];
 936                 else
 937                         name = default_ll_merge;
 938         }
 939         else
 940                 name = merge_attr;
 941
 942         for (fn = ll_user_merge; fn; fn = fn->next)
 943                 if (!strcmp(fn->name, name))
 944                         return fn;
 945
 946         for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
 947                 if (!strcmp(ll_merge_drv[i].name, name))
 948                         return &ll_merge_drv[i];
 949
 950         /* default to the 3-way */
 951         return &ll_merge_drv[LL_TEXT_MERGE];
 952 }
 953
 954 static const char *git_path_check_merge(const char *path)
 955 {
 956         static struct git_attr_check attr_merge_check;
 957
 958         if (!attr_merge_check.attr)
 959                 attr_merge_check.attr = git_attr("merge", 5);
 960
 961         if (git_checkattr(path, 1, &attr_merge_check))
 962                 return NULL;
 963         return attr_merge_check.value;
 964 }
 965
 966 static int ll_merge(mmbuffer_t *result_buf,
 967                     struct diff_filespec *o,
 968                     struct diff_filespec *a,
 969                     struct diff_filespec *b,
 970                     const char *branch1,
 971                     const char *branch2)
 972 {
 973         mmfile_t orig, src1, src2;
 974         char *name1, *name2;
 975         int merge_status;
 976         const char *ll_driver_name;
 977         const struct ll_merge_driver *driver;
 978
 979         name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 980         name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 981
 982         fill_mm(o->sha1, &orig);
 983         fill_mm(a->sha1, &src1);
 984         fill_mm(b->sha1, &src2);
 985
 986         ll_driver_name = git_path_check_merge(a->path);
 987         driver = find_ll_merge_driver(ll_driver_name);
 988
 989         if (index_only && driver->recursive)
 990                 driver = find_ll_merge_driver(driver->recursive);
 991         merge_status = driver->fn(driver, a->path,
 992                                   &orig, &src1, name1, &src2, name2,
 993                                   result_buf);
 994
 995         free(name1);
 996         free(name2);
 997         free(orig.ptr);
 998         free(src1.ptr);
 999         free(src2.ptr);
1000         return merge_status;
1001 }
1002
1003 static struct merge_file_info merge_file(struct diff_filespec *o,
1004                 struct diff_filespec *a, struct diff_filespec *b,
1005                 const char *branch1, const char *branch2)
1006 {
1007         struct merge_file_info result;
1008         result.merge = 0;
1009         result.clean = 1;
1010
1011         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
1012                 result.clean = 0;
1013                 if (S_ISREG(a->mode)) {
1014                         result.mode = a->mode;
1015                         hashcpy(result.sha, a->sha1);
1016                 } else {
1017                         result.mode = b->mode;
1018                         hashcpy(result.sha, b->sha1);
1019                 }
1020         } else {
1021                 if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
1022                         result.merge = 1;
1023
1024                 result.mode = a->mode == o->mode ? b->mode: a->mode;
1025
1026                 if (sha_eq(a->sha1, o->sha1))
1027                         hashcpy(result.sha, b->sha1);
1028                 else if (sha_eq(b->sha1, o->sha1))
1029                         hashcpy(result.sha, a->sha1);
1030                 else if (S_ISREG(a->mode)) {
1031                         mmbuffer_t result_buf;
1032                         int merge_status;
1033
1034                         merge_status = ll_merge(&result_buf, o, a, b,
1035                                                 branch1, branch2);
1036
1037                         if ((merge_status < 0) || !result_buf.ptr)
1038                                 die("Failed to execute internal merge");
1039
1040                         if (write_sha1_file(result_buf.ptr, result_buf.size,
1041                                             blob_type, result.sha))
1042                                 die("Unable to add %s to database",
1043                                     a->path);
1044
1045                         free(result_buf.ptr);
1046                         result.clean = (merge_status == 0);
1047                 } else {
1048                         if (!(S_ISLNK(a->mode) || S_ISLNK(b->mode)))
1049                                 die("cannot merge modes?");
1050
1051                         hashcpy(result.sha, a->sha1);
1052
1053                         if (!sha_eq(a->sha1, b->sha1))
1054                                 result.clean = 0;
1055                 }
1056         }
1057
1058         return result;
1059 }
1060
1061 static void conflict_rename_rename(struct rename *ren1,
1062                                    const char *branch1,
1063                                    struct rename *ren2,
1064                                    const char *branch2)
1065 {
1066         char *del[2];
1067         int delp = 0;
1068         const char *ren1_dst = ren1->pair->two->path;
1069         const char *ren2_dst = ren2->pair->two->path;
1070         const char *dst_name1 = ren1_dst;
1071         const char *dst_name2 = ren2_dst;
1072         if (path_list_has_path(&current_directory_set, ren1_dst)) {
1073                 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
1074                 output(1, "%s is a directory in %s added as %s instead",
1075                        ren1_dst, branch2, dst_name1);
1076                 remove_file(0, ren1_dst, 0);
1077         }
1078         if (path_list_has_path(&current_directory_set, ren2_dst)) {
1079                 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
1080                 output(1, "%s is a directory in %s added as %s instead",
1081                        ren2_dst, branch1, dst_name2);
1082                 remove_file(0, ren2_dst, 0);
1083         }
1084         if (index_only) {
1085                 remove_file_from_cache(dst_name1);
1086                 remove_file_from_cache(dst_name2);
1087                 /*
1088                  * Uncomment to leave the conflicting names in the resulting tree
1089                  *
1090                  * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
1091                  * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
1092                  */
1093         } else {
1094                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
1095                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
1096         }
1097         while (delp--)
1098                 free(del[delp]);
1099 }
1100
1101 static void conflict_rename_dir(struct rename *ren1,
1102                                 const char *branch1)
1103 {
1104         char *new_path = unique_path(ren1->pair->two->path, branch1);
1105         output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
1106         remove_file(0, ren1->pair->two->path, 0);
1107         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
1108         free(new_path);
1109 }
1110
1111 static void conflict_rename_rename_2(struct rename *ren1,
1112                                      const char *branch1,
1113                                      struct rename *ren2,
1114                                      const char *branch2)
1115 {
1116         char *new_path1 = unique_path(ren1->pair->two->path, branch1);
1117         char *new_path2 = unique_path(ren2->pair->two->path, branch2);
1118         output(1, "Renamed %s to %s and %s to %s instead",
1119                ren1->pair->one->path, new_path1,
1120                ren2->pair->one->path, new_path2);
1121         remove_file(0, ren1->pair->two->path, 0);
1122         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
1123         update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
1124         free(new_path2);
1125         free(new_path1);
1126 }
1127
1128 static int process_renames(struct path_list *a_renames,
1129                            struct path_list *b_renames,
1130                            const char *a_branch,
1131                            const char *b_branch)
1132 {
1133         int clean_merge = 1, i, j;
1134         struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
1135         const struct rename *sre;
1136
1137         for (i = 0; i < a_renames->nr; i++) {
1138                 sre = a_renames->items[i].util;
1139                 path_list_insert(sre->pair->two->path, &a_by_dst)->util
1140                         = sre->dst_entry;
1141         }
1142         for (i = 0; i < b_renames->nr; i++) {
1143                 sre = b_renames->items[i].util;
1144                 path_list_insert(sre->pair->two->path, &b_by_dst)->util
1145                         = sre->dst_entry;
1146         }
1147
1148         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1149                 int compare;
1150                 char *src;
1151                 struct path_list *renames1, *renames2, *renames2Dst;
1152                 struct rename *ren1 = NULL, *ren2 = NULL;
1153                 const char *branch1, *branch2;
1154                 const char *ren1_src, *ren1_dst;
1155
1156                 if (i >= a_renames->nr) {
1157                         compare = 1;
1158                         ren2 = b_renames->items[j++].util;
1159                 } else if (j >= b_renames->nr) {
1160                         compare = -1;
1161                         ren1 = a_renames->items[i++].util;
1162                 } else {
1163                         compare = strcmp(a_renames->items[i].path,
1164                                         b_renames->items[j].path);
1165                         if (compare <= 0)
1166                                 ren1 = a_renames->items[i++].util;
1167                         if (compare >= 0)
1168                                 ren2 = b_renames->items[j++].util;
1169                 }
1170
1171                 /* TODO: refactor, so that 1/2 are not needed */
1172                 if (ren1) {
1173                         renames1 = a_renames;
1174                         renames2 = b_renames;
1175                         renames2Dst = &b_by_dst;
1176                         branch1 = a_branch;
1177                         branch2 = b_branch;
1178                 } else {
1179                         struct rename *tmp;
1180                         renames1 = b_renames;
1181                         renames2 = a_renames;
1182                         renames2Dst = &a_by_dst;
1183                         branch1 = b_branch;
1184                         branch2 = a_branch;
1185                         tmp = ren2;
1186                         ren2 = ren1;
1187                         ren1 = tmp;
1188                 }
1189                 src = ren1->pair->one->path;
1190
1191                 ren1->dst_entry->processed = 1;
1192                 ren1->src_entry->processed = 1;
1193
1194                 if (ren1->processed)
1195                         continue;
1196                 ren1->processed = 1;
1197
1198                 ren1_src = ren1->pair->one->path;
1199                 ren1_dst = ren1->pair->two->path;
1200
1201                 if (ren2) {
1202                         const char *ren2_src = ren2->pair->one->path;
1203                         const char *ren2_dst = ren2->pair->two->path;
1204                         /* Renamed in 1 and renamed in 2 */
1205                         if (strcmp(ren1_src, ren2_src) != 0)
1206                                 die("ren1.src != ren2.src");
1207                         ren2->dst_entry->processed = 1;
1208                         ren2->processed = 1;
1209                         if (strcmp(ren1_dst, ren2_dst) != 0) {
1210                                 clean_merge = 0;
1211                                 output(1, "CONFLICT (rename/rename): "
1212                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
1213                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
1214                                        src, ren1_dst, branch1,
1215                                        src, ren2_dst, branch2,
1216                                        index_only ? " (left unresolved)": "");
1217                                 if (index_only) {
1218                                         remove_file_from_cache(src);
1219                                         update_file(0, ren1->pair->one->sha1,
1220                                                     ren1->pair->one->mode, src);
1221                                 }
1222                                 conflict_rename_rename(ren1, branch1, ren2, branch2);
1223                         } else {
1224                                 struct merge_file_info mfi;
1225                                 remove_file(1, ren1_src, 1);
1226                                 mfi = merge_file(ren1->pair->one,
1227                                                  ren1->pair->two,
1228                                                  ren2->pair->two,
1229                                                  branch1,
1230                                                  branch2);
1231                                 if (mfi.merge || !mfi.clean)
1232                                         output(1, "Renamed %s->%s", src, ren1_dst);
1233
1234                                 if (mfi.merge)
1235                                         output(2, "Auto-merged %s", ren1_dst);
1236
1237                                 if (!mfi.clean) {
1238                                         output(1, "CONFLICT (content): merge conflict in %s",
1239                                                ren1_dst);
1240                                         clean_merge = 0;
1241
1242                                         if (!index_only)
1243                                                 update_stages(ren1_dst,
1244                                                               ren1->pair->one,
1245                                                               ren1->pair->two,
1246                                                               ren2->pair->two,
1247                                                               1 /* clear */);
1248                                 }
1249                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1250                         }
1251                 } else {
1252                         /* Renamed in 1, maybe changed in 2 */
1253                         struct path_list_item *item;
1254                         /* we only use sha1 and mode of these */
1255                         struct diff_filespec src_other, dst_other;
1256                         int try_merge, stage = a_renames == renames1 ? 3: 2;
1257
1258                         remove_file(1, ren1_src, index_only || stage == 3);
1259
1260                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
1261                         src_other.mode = ren1->src_entry->stages[stage].mode;
1262                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
1263                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
1264
1265                         try_merge = 0;
1266
1267                         if (path_list_has_path(&current_directory_set, ren1_dst)) {
1268                                 clean_merge = 0;
1269                                 output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
1270                                        " directory %s added in %s",
1271                                        ren1_src, ren1_dst, branch1,
1272                                        ren1_dst, branch2);
1273                                 conflict_rename_dir(ren1, branch1);
1274                         } else if (sha_eq(src_other.sha1, null_sha1)) {
1275                                 clean_merge = 0;
1276                                 output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
1277                                        "and deleted in %s",
1278                                        ren1_src, ren1_dst, branch1,
1279                                        branch2);
1280                                 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
1281                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1282                                 const char *new_path;
1283                                 clean_merge = 0;
1284                                 try_merge = 1;
1285                                 output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
1286                                        "%s added in %s",
1287                                        ren1_src, ren1_dst, branch1,
1288                                        ren1_dst, branch2);
1289                                 new_path = unique_path(ren1_dst, branch2);
1290                                 output(1, "Added as %s instead", new_path);
1291                                 update_file(0, dst_other.sha1, dst_other.mode, new_path);
1292                         } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
1293                                 ren2 = item->util;
1294                                 clean_merge = 0;
1295                                 ren2->processed = 1;
1296                                 output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
1297                                        "Renamed %s->%s in %s",
1298                                        ren1_src, ren1_dst, branch1,
1299                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1300                                 conflict_rename_rename_2(ren1, branch1, ren2, branch2);
1301                         } else
1302                                 try_merge = 1;
1303
1304                         if (try_merge) {
1305                                 struct diff_filespec *o, *a, *b;
1306                                 struct merge_file_info mfi;
1307                                 src_other.path = (char *)ren1_src;
1308
1309                                 o = ren1->pair->one;
1310                                 if (a_renames == renames1) {
1311                                         a = ren1->pair->two;
1312                                         b = &src_other;
1313                                 } else {
1314                                         b = ren1->pair->two;
1315                                         a = &src_other;
1316                                 }
1317                                 mfi = merge_file(o, a, b,
1318                                                 a_branch, b_branch);
1319
1320                                 if (mfi.clean &&
1321                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1322                                     mfi.mode == ren1->pair->two->mode)
1323                                         /*
1324                                          * This messaged is part of
1325                                          * t6022 test. If you change
1326                                          * it update the test too.
1327                                          */
1328                                         output(3, "Skipped %s (merged same as existing)", ren1_dst);
1329                                 else {
1330                                         if (mfi.merge || !mfi.clean)
1331                                                 output(1, "Renamed %s => %s", ren1_src, ren1_dst);
1332                                         if (mfi.merge)
1333                                                 output(2, "Auto-merged %s", ren1_dst);
1334                                         if (!mfi.clean) {
1335                                                 output(1, "CONFLICT (rename/modify): Merge conflict in %s",
1336                                                        ren1_dst);
1337                                                 clean_merge = 0;
1338
1339                                                 if (!index_only)
1340                                                         update_stages(ren1_dst,
1341                                                                       o, a, b, 1);
1342                                         }
1343                                         update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1344                                 }
1345                         }
1346                 }
1347         }
1348         path_list_clear(&a_by_dst, 0);
1349         path_list_clear(&b_by_dst, 0);
1350
1351         return clean_merge;
1352 }
1353
1354 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1355 {
1356         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1357 }
1358
1359 /* Per entry merge function */
1360 static int process_entry(const char *path, struct stage_data *entry,
1361                          const char *branch1,
1362                          const char *branch2)
1363 {
1364         /*
1365         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1366         print_index_entry("\tpath: ", entry);
1367         */
1368         int clean_merge = 1;
1369         unsigned o_mode = entry->stages[1].mode;
1370         unsigned a_mode = entry->stages[2].mode;
1371         unsigned b_mode = entry->stages[3].mode;
1372         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1373         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1374         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1375
1376         if (o_sha && (!a_sha || !b_sha)) {
1377                 /* Case A: Deleted in one */
1378                 if ((!a_sha && !b_sha) ||
1379                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1380                     (!a_sha && sha_eq(b_sha, o_sha))) {
1381                         /* Deleted in both or deleted in one and
1382                          * unchanged in the other */
1383                         if (a_sha)
1384                                 output(2, "Removed %s", path);
1385                         /* do not touch working file if it did not exist */
1386                         remove_file(1, path, !a_sha);
1387                 } else {
1388                         /* Deleted in one and changed in the other */
1389                         clean_merge = 0;
1390                         if (!a_sha) {
1391                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1392                                        "and modified in %s. Version %s of %s left in tree.",
1393                                        path, branch1,
1394                                        branch2, branch2, path);
1395                                 update_file(0, b_sha, b_mode, path);
1396                         } else {
1397                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1398                                        "and modified in %s. Version %s of %s left in tree.",
1399                                        path, branch2,
1400                                        branch1, branch1, path);
1401                                 update_file(0, a_sha, a_mode, path);
1402                         }
1403                 }
1404
1405         } else if ((!o_sha && a_sha && !b_sha) ||
1406                    (!o_sha && !a_sha && b_sha)) {
1407                 /* Case B: Added in one. */
1408                 const char *add_branch;
1409                 const char *other_branch;
1410                 unsigned mode;
1411                 const unsigned char *sha;
1412                 const char *conf;
1413
1414                 if (a_sha) {
1415                         add_branch = branch1;
1416                         other_branch = branch2;
1417                         mode = a_mode;
1418                         sha = a_sha;
1419                         conf = "file/directory";
1420                 } else {
1421                         add_branch = branch2;
1422                         other_branch = branch1;
1423                         mode = b_mode;
1424                         sha = b_sha;
1425                         conf = "directory/file";
1426                 }
1427                 if (path_list_has_path(&current_directory_set, path)) {
1428                         const char *new_path = unique_path(path, add_branch);
1429                         clean_merge = 0;
1430                         output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
1431                                "Added %s as %s",
1432                                conf, path, other_branch, path, new_path);
1433                         remove_file(0, path, 0);
1434                         update_file(0, sha, mode, new_path);
1435                 } else {
1436                         output(2, "Added %s", path);
1437                         update_file(1, sha, mode, path);
1438                 }
1439         } else if (a_sha && b_sha) {
1440                 /* Case C: Added in both (check for same permissions) and */
1441                 /* case D: Modified in both, but differently. */
1442                 const char *reason = "content";
1443                 struct merge_file_info mfi;
1444                 struct diff_filespec o, a, b;
1445
1446                 if (!o_sha) {
1447                         reason = "add/add";
1448                         o_sha = (unsigned char *)null_sha1;
1449                 }
1450                 output(2, "Auto-merged %s", path);
1451                 o.path = a.path = b.path = (char *)path;
1452                 hashcpy(o.sha1, o_sha);
1453                 o.mode = o_mode;
1454                 hashcpy(a.sha1, a_sha);
1455                 a.mode = a_mode;
1456                 hashcpy(b.sha1, b_sha);
1457                 b.mode = b_mode;
1458
1459                 mfi = merge_file(&o, &a, &b,
1460                                  branch1, branch2);
1461
1462                 if (mfi.clean)
1463                         update_file(1, mfi.sha, mfi.mode, path);
1464                 else {
1465                         clean_merge = 0;
1466                         output(1, "CONFLICT (%s): Merge conflict in %s",
1467                                         reason, path);
1468
1469                         if (index_only)
1470                                 update_file(0, mfi.sha, mfi.mode, path);
1471                         else
1472                                 update_file_flags(mfi.sha, mfi.mode, path,
1473                                               0 /* update_cache */, 1 /* update_working_directory */);
1474                 }
1475         } else if (!o_sha && !a_sha && !b_sha) {
1476                 /*
1477                  * this entry was deleted altogether. a_mode == 0 means
1478                  * we had that path and want to actively remove it.
1479                  */
1480                 remove_file(1, path, !a_mode);
1481         } else
1482                 die("Fatal merge failure, shouldn't happen.");
1483
1484         return clean_merge;
1485 }
1486
1487 static int merge_trees(struct tree *head,
1488                        struct tree *merge,
1489                        struct tree *common,
1490                        const char *branch1,
1491                        const char *branch2,
1492                        struct tree **result)
1493 {
1494         int code, clean;
1495
1496         if (subtree_merge) {
1497                 merge = shift_tree_object(head, merge);
1498                 common = shift_tree_object(head, common);
1499         }
1500
1501         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1502                 output(0, "Already uptodate!");
1503                 *result = head;
1504                 return 1;
1505         }
1506
1507         code = git_merge_trees(index_only, common, head, merge);
1508
1509         if (code != 0)
1510                 die("merging of trees %s and %s failed",
1511                     sha1_to_hex(head->object.sha1),
1512                     sha1_to_hex(merge->object.sha1));
1513
1514         if (unmerged_index()) {
1515                 struct path_list *entries, *re_head, *re_merge;
1516                 int i;
1517                 path_list_clear(&current_file_set, 1);
1518                 path_list_clear(&current_directory_set, 1);
1519                 get_files_dirs(head);
1520                 get_files_dirs(merge);
1521
1522                 entries = get_unmerged();
1523                 re_head  = get_renames(head, common, head, merge, entries);
1524                 re_merge = get_renames(merge, common, head, merge, entries);
1525                 clean = process_renames(re_head, re_merge,
1526                                 branch1, branch2);
1527                 for (i = 0; i < entries->nr; i++) {
1528                         const char *path = entries->items[i].path;
1529                         struct stage_data *e = entries->items[i].util;
1530                         if (!e->processed
1531                                 && !process_entry(path, e, branch1, branch2))
1532                                 clean = 0;
1533                 }
1534
1535                 path_list_clear(re_merge, 0);
1536                 path_list_clear(re_head, 0);
1537                 path_list_clear(entries, 1);
1538
1539         }
1540         else
1541                 clean = 1;
1542
1543         if (index_only)
1544                 *result = git_write_tree();
1545
1546         return clean;
1547 }
1548
1549 static struct commit_list *reverse_commit_list(struct commit_list *list)
1550 {
1551         struct commit_list *next = NULL, *current, *backup;
1552         for (current = list; current; current = backup) {
1553                 backup = current->next;
1554                 current->next = next;
1555                 next = current;
1556         }
1557         return next;
1558 }
1559
1560 /*
1561  * Merge the commits h1 and h2, return the resulting virtual
1562  * commit object and a flag indicating the cleanness of the merge.
1563  */
1564 static int merge(struct commit *h1,
1565                  struct commit *h2,
1566                  const char *branch1,
1567                  const char *branch2,
1568                  struct commit_list *ca,
1569                  struct commit **result)
1570 {
1571         struct commit_list *iter;
1572         struct commit *merged_common_ancestors;
1573         struct tree *mrtree;
1574         int clean;
1575
1576         if (show(4)) {
1577                 output(4, "Merging:");
1578                 output_commit_title(h1);
1579                 output_commit_title(h2);
1580         }
1581
1582         if (!ca) {
1583                 ca = get_merge_bases(h1, h2, 1);
1584                 ca = reverse_commit_list(ca);
1585         }
1586
1587         if (show(5)) {
1588                 output(5, "found %u common ancestor(s):", commit_list_count(ca));
1589                 for (iter = ca; iter; iter = iter->next)
1590                         output_commit_title(iter->item);
1591         }
1592
1593         merged_common_ancestors = pop_commit(&ca);
1594         if (merged_common_ancestors == NULL) {
1595                 /* if there is no common ancestor, make an empty tree */
1596                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1597
1598                 tree->object.parsed = 1;
1599                 tree->object.type = OBJ_TREE;
1600                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1601                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1602         }
1603
1604         for (iter = ca; iter; iter = iter->next) {
1605                 call_depth++;
1606                 /*
1607                  * When the merge fails, the result contains files
1608                  * with conflict markers. The cleanness flag is
1609                  * ignored, it was never actually used, as result of
1610                  * merge_trees has always overwritten it: the committed
1611                  * "conflicts" were already resolved.
1612                  */
1613                 discard_cache();
1614                 merge(merged_common_ancestors, iter->item,
1615                       "Temporary merge branch 1",
1616                       "Temporary merge branch 2",
1617                       NULL,
1618                       &merged_common_ancestors);
1619                 call_depth--;
1620
1621                 if (!merged_common_ancestors)
1622                         die("merge returned no commit");
1623         }
1624
1625         discard_cache();
1626         if (!call_depth) {
1627                 read_cache();
1628                 index_only = 0;
1629         } else
1630                 index_only = 1;
1631
1632         clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1633                             branch1, branch2, &mrtree);
1634
1635         if (index_only) {
1636                 *result = make_virtual_commit(mrtree, "merged tree");
1637                 commit_list_insert(h1, &(*result)->parents);
1638                 commit_list_insert(h2, &(*result)->parents->next);
1639         }
1640         flush_output();
1641         return clean;
1642 }
1643
1644 static const char *better_branch_name(const char *branch)
1645 {
1646         static char githead_env[8 + 40 + 1];
1647         char *name;
1648
1649         if (strlen(branch) != 40)
1650                 return branch;
1651         sprintf(githead_env, "GITHEAD_%s", branch);
1652         name = getenv(githead_env);
1653         return name ? name : branch;
1654 }
1655
1656 static struct commit *get_ref(const char *ref)
1657 {
1658         unsigned char sha1[20];
1659         struct object *object;
1660
1661         if (get_sha1(ref, sha1))
1662                 die("Could not resolve ref '%s'", ref);
1663         object = deref_tag(parse_object(sha1), ref, strlen(ref));
1664         if (object->type == OBJ_TREE)
1665                 return make_virtual_commit((struct tree*)object,
1666                         better_branch_name(ref));
1667         if (object->type != OBJ_COMMIT)
1668                 return NULL;
1669         if (parse_commit((struct commit *)object))
1670                 die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1671         return (struct commit *)object;
1672 }
1673
1674 static int merge_config(const char *var, const char *value)
1675 {
1676         if (!strcasecmp(var, "merge.verbosity")) {
1677                 verbosity = git_config_int(var, value);
1678                 return 0;
1679         }
1680         return git_default_config(var, value);
1681 }
1682
1683 int main(int argc, char *argv[])
1684 {
1685         static const char *bases[20];
1686         static unsigned bases_count = 0;
1687         int i, clean;
1688         const char *branch1, *branch2;
1689         struct commit *result, *h1, *h2;
1690         struct commit_list *ca = NULL;
1691         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1692         int index_fd;
1693
1694         if (argv[0]) {
1695                 int namelen = strlen(argv[0]);
1696                 if (8 < namelen &&
1697                     !strcmp(argv[0] + namelen - 8, "-subtree"))
1698                         subtree_merge = 1;
1699         }
1700
1701         git_config(merge_config);
1702         if (getenv("GIT_MERGE_VERBOSITY"))
1703                 verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1704
1705         if (argc < 4)
1706                 die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1707
1708         for (i = 1; i < argc; ++i) {
1709                 if (!strcmp(argv[i], "--"))
1710                         break;
1711                 if (bases_count < sizeof(bases)/sizeof(*bases))
1712                         bases[bases_count++] = argv[i];
1713         }
1714         if (argc - i != 3) /* "--" "<head>" "<remote>" */
1715                 die("Not handling anything other than two heads merge.");
1716         if (verbosity >= 5)
1717                 buffer_output = 0;
1718
1719         branch1 = argv[++i];
1720         branch2 = argv[++i];
1721
1722         h1 = get_ref(branch1);
1723         h2 = get_ref(branch2);
1724
1725         branch1 = better_branch_name(branch1);
1726         branch2 = better_branch_name(branch2);
1727
1728         if (show(3))
1729                 printf("Merging %s with %s\n", branch1, branch2);
1730
1731         index_fd = hold_locked_index(lock, 1);
1732
1733         for (i = 0; i < bases_count; i++) {
1734                 struct commit *ancestor = get_ref(bases[i]);
1735                 ca = commit_list_insert(ancestor, &ca);
1736         }
1737         clean = merge(h1, h2, branch1, branch2, ca, &result);
1738
1739         if (active_cache_changed &&
1740             (write_cache(index_fd, active_cache, active_nr) ||
1741              close(index_fd) || commit_locked_index(lock)))
1742                         die ("unable to write %s", get_index_file());
1743
1744         return clean ? 0: 1;
1745 }