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 <stdarg.h>
   7 #include <string.h>
   8 #include <assert.h>
   9 #include <sys/wait.h>
  10 #include <sys/types.h>
  11 #include <sys/stat.h>
  12 #include <time.h>
  13 #include "cache.h"
  14 #include "cache-tree.h"
  15 #include "commit.h"
  16 #include "blob.h"
  17 #include "tree-walk.h"
  18 #include "diff.h"
  19 #include "diffcore.h"
  20 #include "run-command.h"
  21 #include "tag.h"
  22
  23 #include "path-list.h"
  24
  25 /*
  26  * A virtual commit has
  27  * - (const char *)commit->util set to the name, and
  28  * - *(int *)commit->object.sha1 set to the virtual id.
  29  */
  30
  31 static unsigned commit_list_count(const struct commit_list *l)
  32 {
  33         unsigned c = 0;
  34         for (; l; l = l->next )
  35                 c++;
  36         return c;
  37 }
  38
  39 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  40 {
  41         struct commit *commit = xcalloc(1, sizeof(struct commit));
  42         static unsigned virtual_id = 1;
  43         commit->tree = tree;
  44         commit->util = (void*)comment;
  45         *(int*)commit->object.sha1 = virtual_id++;
  46         return commit;
  47 }
  48
  49 /*
  50  * TODO: we should not have to copy the SHA1s around, but rather reference
  51  * them. That way, sha_eq() is just sha1 == sha2.
  52  */
  53 static int sha_eq(const unsigned char *a, const unsigned char *b)
  54 {
  55         if (!a && !b)
  56                 return 2;
  57         return a && b && memcmp(a, b, 20) == 0;
  58 }
  59
  60 /*
  61  * TODO: check if we can just reuse the active_cache structure: it is already
  62  * sorted (by name, stage).
  63  * Only problem: do not write it when flushing the cache.
  64  */
  65 struct stage_data
  66 {
  67         struct
  68         {
  69                 unsigned mode;
  70                 unsigned char sha[20];
  71         } stages[4];
  72         unsigned processed:1;
  73 };
  74
  75 static struct path_list current_file_set = {NULL, 0, 0, 1};
  76 static struct path_list current_directory_set = {NULL, 0, 0, 1};
  77
  78 static int output_indent = 0;
  79
  80 static void output(const char *fmt, ...)
  81 {
  82         va_list args;
  83         int i;
  84         for (i = output_indent; i--;)
  85                 fputs("  ", stdout);
  86         va_start(args, fmt);
  87         vfprintf(stdout, fmt, args);
  88         va_end(args);
  89         fputc('\n', stdout);
  90 }
  91
  92 static void output_commit_title(struct commit *commit)
  93 {
  94         int i;
  95         for (i = output_indent; i--;)
  96                 fputs("  ", stdout);
  97         if (commit->util)
  98                 printf("virtual %s\n", (char *)commit->util);
  99         else {
 100                 printf("%s ", sha1_to_hex(commit->object.sha1));
 101                 if (parse_commit(commit) != 0)
 102                         printf("(bad commit)\n");
 103                 else {
 104                         const char *s;
 105                         int len;
 106                         for (s = commit->buffer; *s; s++)
 107                                 if (*s == '\n' && s[1] == '\n') {
 108                                         s += 2;
 109                                         break;
 110                                 }
 111                         for (len = 0; s[len] && '\n' != s[len]; len++)
 112                                 ; /* do nothing */
 113                         printf("%.*s\n", len, s);
 114                 }
 115         }
 116 }
 117
 118 static const char *original_index_file;
 119 static const char *temporary_index_file;
 120 static int cache_dirty = 0;
 121
 122 static int flush_cache(void)
 123 {
 124         /* flush temporary index */
 125         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 126         int fd = hold_lock_file_for_update(lock, getenv("GIT_INDEX_FILE"));
 127         if (fd < 0)
 128                 die("could not lock %s", temporary_index_file);
 129         if (write_cache(fd, active_cache, active_nr) ||
 130                         close(fd) || commit_lock_file(lock))
 131                 die ("unable to write %s", getenv("GIT_INDEX_FILE"));
 132         discard_cache();
 133         cache_dirty = 0;
 134         return 0;
 135 }
 136
 137 static void setup_index(int temp)
 138 {
 139         const char *idx = temp ? temporary_index_file: original_index_file;
 140         if (cache_dirty)
 141                 die("fatal: cache changed flush_cache();");
 142         unlink(temporary_index_file);
 143         setenv("GIT_INDEX_FILE", idx, 1);
 144         discard_cache();
 145 }
 146
 147 static struct cache_entry *make_cache_entry(unsigned int mode,
 148                 const unsigned char *sha1, const char *path, int stage, int refresh)
 149 {
 150         int size, len;
 151         struct cache_entry *ce;
 152
 153         if (!verify_path(path))
 154                 return NULL;
 155
 156         len = strlen(path);
 157         size = cache_entry_size(len);
 158         ce = xcalloc(1, size);
 159
 160         memcpy(ce->sha1, sha1, 20);
 161         memcpy(ce->name, path, len);
 162         ce->ce_flags = create_ce_flags(len, stage);
 163         ce->ce_mode = create_ce_mode(mode);
 164
 165         if (refresh)
 166                 return refresh_cache_entry(ce, 0);
 167
 168         return ce;
 169 }
 170
 171 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 172                 const char *path, int stage, int refresh, int options)
 173 {
 174         struct cache_entry *ce;
 175         if (!cache_dirty)
 176                 read_cache_from(getenv("GIT_INDEX_FILE"));
 177         cache_dirty++;
 178         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 179         if (!ce)
 180                 return error("cache_addinfo failed: %s", strerror(cache_errno));
 181         return add_cache_entry(ce, options);
 182 }
 183
 184 /*
 185  * This is a global variable which is used in a number of places but
 186  * only written to in the 'merge' function.
 187  *
 188  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
 189  *                       don't update the working directory.
 190  *               0    => Leave unmerged entries in the cache and update
 191  *                       the working directory.
 192  */
 193 static int index_only = 0;
 194
 195 /*
 196  * TODO: this can be streamlined by refactoring builtin-read-tree.c
 197  */
 198 static int git_read_tree(const struct tree *tree)
 199 {
 200         int rc;
 201         const char *argv[] = { "git-read-tree", NULL, NULL, };
 202         if (cache_dirty)
 203                 die("read-tree with dirty cache");
 204         argv[1] = sha1_to_hex(tree->object.sha1);
 205         rc = run_command_v(2, argv);
 206         return rc < 0 ? -1: rc;
 207 }
 208
 209 /*
 210  * TODO: this can be streamlined by refactoring builtin-read-tree.c
 211  */
 212 static int git_merge_trees(const char *update_arg,
 213                            struct tree *common,
 214                            struct tree *head,
 215                            struct tree *merge)
 216 {
 217         int rc;
 218         const char *argv[] = {
 219                 "git-read-tree", NULL, "-m", NULL, NULL, NULL,
 220                 NULL,
 221         };
 222         if (cache_dirty)
 223                 flush_cache();
 224         argv[1] = update_arg;
 225         argv[3] = sha1_to_hex(common->object.sha1);
 226         argv[4] = sha1_to_hex(head->object.sha1);
 227         argv[5] = sha1_to_hex(merge->object.sha1);
 228         rc = run_command_v(6, argv);
 229         return rc < 0 ? -1: rc;
 230 }
 231
 232 /*
 233  * TODO: this can be streamlined by refactoring builtin-write-tree.c
 234  */
 235 static struct tree *git_write_tree(void)
 236 {
 237         FILE *fp;
 238         int rc;
 239         char buf[41];
 240         unsigned char sha1[20];
 241         int ch;
 242         unsigned i = 0;
 243         if (cache_dirty)
 244                 flush_cache();
 245         fp = popen("git-write-tree 2>/dev/null", "r");
 246         while ((ch = fgetc(fp)) != EOF)
 247                 if (i < sizeof(buf)-1 && ch >= '0' && ch <= 'f')
 248                         buf[i++] = ch;
 249                 else
 250                         break;
 251         rc = pclose(fp);
 252         if (rc == -1 || WEXITSTATUS(rc))
 253                 return NULL;
 254         buf[i] = '\0';
 255         if (get_sha1(buf, sha1) != 0)
 256                 return NULL;
 257         return lookup_tree(sha1);
 258 }
 259
 260 static int save_files_dirs(const unsigned char *sha1,
 261                 const char *base, int baselen, const char *path,
 262                 unsigned int mode, int stage)
 263 {
 264         int len = strlen(path);
 265         char *newpath = malloc(baselen + len + 1);
 266         memcpy(newpath, base, baselen);
 267         memcpy(newpath + baselen, path, len);
 268         newpath[baselen + len] = '\0';
 269
 270         if (S_ISDIR(mode))
 271                 path_list_insert(newpath, &current_directory_set);
 272         else
 273                 path_list_insert(newpath, &current_file_set);
 274         free(newpath);
 275
 276         return READ_TREE_RECURSIVE;
 277 }
 278
 279 static int get_files_dirs(struct tree *tree)
 280 {
 281         int n;
 282         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
 283                 return 0;
 284         n = current_file_set.nr + current_directory_set.nr;
 285         return n;
 286 }
 287
 288 /*
 289  * Returns a index_entry instance which doesn't have to correspond to
 290  * a real cache entry in Git's index.
 291  */
 292 static struct stage_data *insert_stage_data(const char *path,
 293                 struct tree *o, struct tree *a, struct tree *b,
 294                 struct path_list *entries)
 295 {
 296         struct path_list_item *item;
 297         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 298         get_tree_entry(o->object.sha1, path,
 299                         e->stages[1].sha, &e->stages[1].mode);
 300         get_tree_entry(a->object.sha1, path,
 301                         e->stages[2].sha, &e->stages[2].mode);
 302         get_tree_entry(b->object.sha1, path,
 303                         e->stages[3].sha, &e->stages[3].mode);
 304         item = path_list_insert(path, entries);
 305         item->util = e;
 306         return e;
 307 }
 308
 309 /*
 310  * Create a dictionary mapping file names to stage_data objects. The
 311  * dictionary contains one entry for every path with a non-zero stage entry.
 312  */
 313 static struct path_list *get_unmerged(void)
 314 {
 315         struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
 316         int i;
 317
 318         unmerged->strdup_paths = 1;
 319         if (!cache_dirty) {
 320                 read_cache_from(getenv("GIT_INDEX_FILE"));
 321                 cache_dirty++;
 322         }
 323         for (i = 0; i < active_nr; i++) {
 324                 struct path_list_item *item;
 325                 struct stage_data *e;
 326                 struct cache_entry *ce = active_cache[i];
 327                 if (!ce_stage(ce))
 328                         continue;
 329
 330                 item = path_list_lookup(ce->name, unmerged);
 331                 if (!item) {
 332                         item = path_list_insert(ce->name, unmerged);
 333                         item->util = xcalloc(1, sizeof(struct stage_data));
 334                 }
 335                 e = item->util;
 336                 e->stages[ce_stage(ce)].mode = ntohl(ce->ce_mode);
 337                 memcpy(e->stages[ce_stage(ce)].sha, ce->sha1, 20);
 338         }
 339
 340         return unmerged;
 341 }
 342
 343 struct rename
 344 {
 345         struct diff_filepair *pair;
 346         struct stage_data *src_entry;
 347         struct stage_data *dst_entry;
 348         unsigned processed:1;
 349 };
 350
 351 /*
 352  * Get information of all renames which occured between 'o_tree' and
 353  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 354  * 'b_tree') to be able to associate the correct cache entries with
 355  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 356  */
 357 static struct path_list *get_renames(struct tree *tree,
 358                                         struct tree *o_tree,
 359                                         struct tree *a_tree,
 360                                         struct tree *b_tree,
 361                                         struct path_list *entries)
 362 {
 363         int i;
 364         struct path_list *renames;
 365         struct diff_options opts;
 366
 367         renames = xcalloc(1, sizeof(struct path_list));
 368         diff_setup(&opts);
 369         opts.recursive = 1;
 370         opts.detect_rename = DIFF_DETECT_RENAME;
 371         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 372         if (diff_setup_done(&opts) < 0)
 373                 die("diff setup failed");
 374         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 375         diffcore_std(&opts);
 376         for (i = 0; i < diff_queued_diff.nr; ++i) {
 377                 struct path_list_item *item;
 378                 struct rename *re;
 379                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 380                 if (pair->status != 'R') {
 381                         diff_free_filepair(pair);
 382                         continue;
 383                 }
 384                 re = xmalloc(sizeof(*re));
 385                 re->processed = 0;
 386                 re->pair = pair;
 387                 item = path_list_lookup(re->pair->one->path, entries);
 388                 if (!item)
 389                         re->src_entry = insert_stage_data(re->pair->one->path,
 390                                         o_tree, a_tree, b_tree, entries);
 391                 else
 392                         re->src_entry = item->util;
 393
 394                 item = path_list_lookup(re->pair->two->path, entries);
 395                 if (!item)
 396                         re->dst_entry = insert_stage_data(re->pair->two->path,
 397                                         o_tree, a_tree, b_tree, entries);
 398                 else
 399                         re->dst_entry = item->util;
 400                 item = path_list_insert(pair->one->path, renames);
 401                 item->util = re;
 402         }
 403         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 404         diff_queued_diff.nr = 0;
 405         diff_flush(&opts);
 406         return renames;
 407 }
 408
 409 int update_stages(const char *path, struct diff_filespec *o,
 410                 struct diff_filespec *a, struct diff_filespec *b, 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, len;
 431         char *slash, *dirs;
 432
 433         ret = unlink(name);
 434         if (ret)
 435                 return ret;
 436         len = strlen(name);
 437         dirs = malloc(len+1);
 438         memcpy(dirs, name, len);
 439         dirs[len] = '\0';
 440         while ((slash = strrchr(name, '/'))) {
 441                 *slash = '\0';
 442                 len = slash - name;
 443                 if (rmdir(name) != 0)
 444                         break;
 445         }
 446         free(dirs);
 447         return ret;
 448 }
 449
 450 /*
 451  * TODO: once we no longer call external programs, we'd probably be better off
 452  * not setting / getting the environment variable GIT_INDEX_FILE all the time.
 453  */
 454 int remove_file(int clean, const char *path)
 455 {
 456         int update_cache = index_only || clean;
 457         int update_working_directory = !index_only;
 458
 459         if (update_cache) {
 460                 if (!cache_dirty)
 461                         read_cache_from(getenv("GIT_INDEX_FILE"));
 462                 cache_dirty++;
 463                 if (remove_file_from_cache(path))
 464                         return -1;
 465         }
 466         if (update_working_directory)
 467         {
 468                 unlink(path);
 469                 if (errno != ENOENT || errno != EISDIR)
 470                         return -1;
 471                 remove_path(path);
 472         }
 473         return 0;
 474 }
 475
 476 static char *unique_path(const char *path, const char *branch)
 477 {
 478         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 479         int suffix = 0;
 480         struct stat st;
 481         char *p = newpath + strlen(newpath);
 482         strcpy(newpath, path);
 483         strcat(newpath, "~");
 484         strcpy(p, branch);
 485         for (; *p; ++p)
 486                 if ('/' == *p)
 487                         *p = '_';
 488         while (path_list_has_path(&current_file_set, newpath) ||
 489                path_list_has_path(&current_directory_set, newpath) ||
 490                lstat(newpath, &st) == 0)
 491                 sprintf(p, "_%d", suffix++);
 492
 493         path_list_insert(newpath, &current_file_set);
 494         return newpath;
 495 }
 496
 497 static int mkdir_p(const char *path, unsigned long mode)
 498 {
 499         /* path points to cache entries, so strdup before messing with it */
 500         char *buf = strdup(path);
 501         int result = safe_create_leading_directories(buf);
 502         free(buf);
 503         return result;
 504 }
 505
 506 static void flush_buffer(int fd, const char *buf, unsigned long size)
 507 {
 508         while (size > 0) {
 509                 long ret = xwrite(fd, buf, size);
 510                 if (ret < 0) {
 511                         /* Ignore epipe */
 512                         if (errno == EPIPE)
 513                                 break;
 514                         die("merge-recursive: %s", strerror(errno));
 515                 } else if (!ret) {
 516                         die("merge-recursive: disk full?");
 517                 }
 518                 size -= ret;
 519                 buf += ret;
 520         }
 521 }
 522
 523 void update_file_flags(const unsigned char *sha,
 524                        unsigned mode,
 525                        const char *path,
 526                        int update_cache,
 527                        int update_wd)
 528 {
 529         if (index_only)
 530                 update_wd = 0;
 531
 532         if (update_wd) {
 533                 char type[20];
 534                 void *buf;
 535                 unsigned long size;
 536
 537                 buf = read_sha1_file(sha, type, &size);
 538                 if (!buf)
 539                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 540                 if (strcmp(type, blob_type) != 0)
 541                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 542
 543                 if (S_ISREG(mode)) {
 544                         int fd;
 545                         if (mkdir_p(path, 0777))
 546                                 die("failed to create path %s: %s", path, strerror(errno));
 547                         unlink(path);
 548                         if (mode & 0100)
 549                                 mode = 0777;
 550                         else
 551                                 mode = 0666;
 552                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 553                         if (fd < 0)
 554                                 die("failed to open %s: %s", path, strerror(errno));
 555                         flush_buffer(fd, buf, size);
 556                         close(fd);
 557                 } else if (S_ISLNK(mode)) {
 558                         char *lnk = malloc(size + 1);
 559                         memcpy(lnk, buf, size);
 560                         lnk[size] = '\0';
 561                         mkdir_p(path, 0777);
 562                         unlink(lnk);
 563                         symlink(lnk, path);
 564                 } else
 565                         die("do not know what to do with %06o %s '%s'",
 566                             mode, sha1_to_hex(sha), path);
 567         }
 568         if (update_cache)
 569                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 570 }
 571
 572 void update_file(int clean,
 573                 const unsigned char *sha,
 574                 unsigned mode,
 575                 const char *path)
 576 {
 577         update_file_flags(sha, mode, path, index_only || clean, !index_only);
 578 }
 579
 580 /* Low level file merging, update and removal */
 581
 582 struct merge_file_info
 583 {
 584         unsigned char sha[20];
 585         unsigned mode;
 586         unsigned clean:1,
 587                  merge:1;
 588 };
 589
 590 static char *git_unpack_file(const unsigned char *sha1, char *path)
 591 {
 592         void *buf;
 593         char type[20];
 594         unsigned long size;
 595         int fd;
 596
 597         buf = read_sha1_file(sha1, type, &size);
 598         if (!buf || strcmp(type, blob_type))
 599                 die("unable to read blob object %s", sha1_to_hex(sha1));
 600
 601         strcpy(path, ".merge_file_XXXXXX");
 602         fd = mkstemp(path);
 603         if (fd < 0)
 604                 die("unable to create temp-file");
 605         flush_buffer(fd, buf, size);
 606         close(fd);
 607         return path;
 608 }
 609
 610 static struct merge_file_info merge_file(struct diff_filespec *o,
 611                 struct diff_filespec *a, struct diff_filespec *b,
 612                 const char *branch1, const char *branch2)
 613 {
 614         struct merge_file_info result;
 615         result.merge = 0;
 616         result.clean = 1;
 617
 618         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 619                 result.clean = 0;
 620                 if (S_ISREG(a->mode)) {
 621                         result.mode = a->mode;
 622                         memcpy(result.sha, a->sha1, 20);
 623                 } else {
 624                         result.mode = b->mode;
 625                         memcpy(result.sha, b->sha1, 20);
 626                 }
 627         } else {
 628                 if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
 629                         result.merge = 1;
 630
 631                 result.mode = a->mode == o->mode ? b->mode: a->mode;
 632
 633                 if (sha_eq(a->sha1, o->sha1))
 634                         memcpy(result.sha, b->sha1, 20);
 635                 else if (sha_eq(b->sha1, o->sha1))
 636                         memcpy(result.sha, a->sha1, 20);
 637                 else if (S_ISREG(a->mode)) {
 638                         int code = 1, fd;
 639                         struct stat st;
 640                         char orig[PATH_MAX];
 641                         char src1[PATH_MAX];
 642                         char src2[PATH_MAX];
 643                         const char *argv[] = {
 644                                 "merge", "-L", NULL, "-L", NULL, "-L", NULL,
 645                                 NULL, NULL, NULL,
 646                                 NULL
 647                         };
 648                         char *la, *lb, *lo;
 649
 650                         git_unpack_file(o->sha1, orig);
 651                         git_unpack_file(a->sha1, src1);
 652                         git_unpack_file(b->sha1, src2);
 653
 654                         argv[2] = la = strdup(mkpath("%s/%s", branch1, a->path));
 655                         argv[6] = lb = strdup(mkpath("%s/%s", branch2, b->path));
 656                         argv[4] = lo = strdup(mkpath("orig/%s", o->path));
 657                         argv[7] = src1;
 658                         argv[8] = orig;
 659                         argv[9] = src2,
 660
 661                         code = run_command_v(10, argv);
 662
 663                         free(la);
 664                         free(lb);
 665                         free(lo);
 666                         if (code && code < -256) {
 667                                 die("Failed to execute 'merge'. merge(1) is used as the "
 668                                     "file-level merge tool. Is 'merge' in your path?");
 669                         }
 670                         fd = open(src1, O_RDONLY);
 671                         if (fd < 0 || fstat(fd, &st) < 0 ||
 672                                         index_fd(result.sha, fd, &st, 1,
 673                                                 "blob"))
 674                                 die("Unable to add %s to database", src1);
 675
 676                         unlink(orig);
 677                         unlink(src1);
 678                         unlink(src2);
 679
 680                         result.clean = WEXITSTATUS(code) == 0;
 681                 } else {
 682                         if (!(S_ISLNK(a->mode) || S_ISLNK(b->mode)))
 683                                 die("cannot merge modes?");
 684
 685                         memcpy(result.sha, a->sha1, 20);
 686
 687                         if (!sha_eq(a->sha1, b->sha1))
 688                                 result.clean = 0;
 689                 }
 690         }
 691
 692         return result;
 693 }
 694
 695 static void conflict_rename_rename(struct rename *ren1,
 696                                    const char *branch1,
 697                                    struct rename *ren2,
 698                                    const char *branch2)
 699 {
 700         char *del[2];
 701         int delp = 0;
 702         const char *ren1_dst = ren1->pair->two->path;
 703         const char *ren2_dst = ren2->pair->two->path;
 704         const char *dst_name1 = ren1_dst;
 705         const char *dst_name2 = ren2_dst;
 706         if (path_list_has_path(&current_directory_set, ren1_dst)) {
 707                 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
 708                 output("%s is a directory in %s adding as %s instead",
 709                        ren1_dst, branch2, dst_name1);
 710                 remove_file(0, ren1_dst);
 711         }
 712         if (path_list_has_path(&current_directory_set, ren2_dst)) {
 713                 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
 714                 output("%s is a directory in %s adding as %s instead",
 715                        ren2_dst, branch1, dst_name2);
 716                 remove_file(0, ren2_dst);
 717         }
 718         update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 719         update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 720         while (delp--)
 721                 free(del[delp]);
 722 }
 723
 724 static void conflict_rename_dir(struct rename *ren1,
 725                                 const char *branch1)
 726 {
 727         char *new_path = unique_path(ren1->pair->two->path, branch1);
 728         output("Renaming %s to %s instead", ren1->pair->one->path, new_path);
 729         remove_file(0, ren1->pair->two->path);
 730         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 731         free(new_path);
 732 }
 733
 734 static void conflict_rename_rename_2(struct rename *ren1,
 735                                      const char *branch1,
 736                                      struct rename *ren2,
 737                                      const char *branch2)
 738 {
 739         char *new_path1 = unique_path(ren1->pair->two->path, branch1);
 740         char *new_path2 = unique_path(ren2->pair->two->path, branch2);
 741         output("Renaming %s to %s and %s to %s instead",
 742                ren1->pair->one->path, new_path1,
 743                ren2->pair->one->path, new_path2);
 744         remove_file(0, ren1->pair->two->path);
 745         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 746         update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 747         free(new_path2);
 748         free(new_path1);
 749 }
 750
 751 static int process_renames(struct path_list *a_renames,
 752                            struct path_list *b_renames,
 753                            const char *a_branch,
 754                            const char *b_branch)
 755 {
 756         int clean_merge = 1, i, j;
 757         struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 758         const struct rename *sre;
 759
 760         for (i = 0; i < a_renames->nr; i++) {
 761                 sre = a_renames->items[i].util;
 762                 path_list_insert(sre->pair->two->path, &a_by_dst)->util
 763                         = sre->dst_entry;
 764         }
 765         for (i = 0; i < b_renames->nr; i++) {
 766                 sre = b_renames->items[i].util;
 767                 path_list_insert(sre->pair->two->path, &b_by_dst)->util
 768                         = sre->dst_entry;
 769         }
 770
 771         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 772                 int compare;
 773                 char *src;
 774                 struct path_list *renames1, *renames2, *renames2Dst;
 775                 struct rename *ren1 = NULL, *ren2 = NULL;
 776                 const char *branch1, *branch2;
 777                 const char *ren1_src, *ren1_dst;
 778
 779                 if (i >= a_renames->nr) {
 780                         compare = 1;
 781                         ren2 = b_renames->items[j++].util;
 782                 } else if (j >= b_renames->nr) {
 783                         compare = -1;
 784                         ren1 = a_renames->items[i++].util;
 785                 } else {
 786                         compare = strcmp(a_renames->items[i].path,
 787                                         b_renames->items[j].path);
 788                         ren1 = a_renames->items[i++].util;
 789                         ren2 = b_renames->items[j++].util;
 790                 }
 791
 792                 /* TODO: refactor, so that 1/2 are not needed */
 793                 if (ren1) {
 794                         renames1 = a_renames;
 795                         renames2 = b_renames;
 796                         renames2Dst = &b_by_dst;
 797                         branch1 = a_branch;
 798                         branch2 = b_branch;
 799                 } else {
 800                         struct rename *tmp;
 801                         renames1 = b_renames;
 802                         renames2 = a_renames;
 803                         renames2Dst = &a_by_dst;
 804                         branch1 = b_branch;
 805                         branch2 = a_branch;
 806                         tmp = ren2;
 807                         ren2 = ren1;
 808                         ren1 = tmp;
 809                 }
 810                 src = ren1->pair->one->path;
 811
 812                 ren1->dst_entry->processed = 1;
 813                 ren1->src_entry->processed = 1;
 814
 815                 if (ren1->processed)
 816                         continue;
 817                 ren1->processed = 1;
 818
 819                 ren1_src = ren1->pair->one->path;
 820                 ren1_dst = ren1->pair->two->path;
 821
 822                 if (ren2) {
 823                         const char *ren2_src = ren2->pair->one->path;
 824                         const char *ren2_dst = ren2->pair->two->path;
 825                         /* Renamed in 1 and renamed in 2 */
 826                         if (strcmp(ren1_src, ren2_src) != 0)
 827                                 die("ren1.src != ren2.src");
 828                         ren2->dst_entry->processed = 1;
 829                         ren2->processed = 1;
 830                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 831                                 clean_merge = 0;
 832                                 output("CONFLICT (rename/rename): "
 833                                        "Rename %s->%s in branch %s "
 834                                        "rename %s->%s in %s",
 835                                        src, ren1_dst, branch1,
 836                                        src, ren2_dst, branch2);
 837                                 conflict_rename_rename(ren1, branch1, ren2, branch2);
 838                         } else {
 839                                 struct merge_file_info mfi;
 840                                 remove_file(1, ren1_src);
 841                                 mfi = merge_file(ren1->pair->one,
 842                                                  ren1->pair->two,
 843                                                  ren2->pair->two,
 844                                                  branch1,
 845                                                  branch2);
 846                                 if (mfi.merge || !mfi.clean)
 847                                         output("Renaming %s->%s", src, ren1_dst);
 848
 849                                 if (mfi.merge)
 850                                         output("Auto-merging %s", ren1_dst);
 851
 852                                 if (!mfi.clean) {
 853                                         output("CONFLICT (content): merge conflict in %s",
 854                                                ren1_dst);
 855                                         clean_merge = 0;
 856
 857                                         if (!index_only)
 858                                                 update_stages(ren1_dst,
 859                                                               ren1->pair->one,
 860                                                               ren1->pair->two,
 861                                                               ren2->pair->two,
 862                                                               1 /* clear */);
 863                                 }
 864                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 865                         }
 866                 } else {
 867                         /* Renamed in 1, maybe changed in 2 */
 868                         struct path_list_item *item;
 869                         /* we only use sha1 and mode of these */
 870                         struct diff_filespec src_other, dst_other;
 871                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 872
 873                         remove_file(1, ren1_src);
 874
 875                         memcpy(src_other.sha1,
 876                                         ren1->src_entry->stages[stage].sha, 20);
 877                         src_other.mode = ren1->src_entry->stages[stage].mode;
 878                         memcpy(dst_other.sha1,
 879                                         ren1->dst_entry->stages[stage].sha, 20);
 880                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 881
 882                         try_merge = 0;
 883
 884                         if (path_list_has_path(&current_directory_set, ren1_dst)) {
 885                                 clean_merge = 0;
 886                                 output("CONFLICT (rename/directory): Rename %s->%s in %s "
 887                                        " directory %s added in %s",
 888                                        ren1_src, ren1_dst, branch1,
 889                                        ren1_dst, branch2);
 890                                 conflict_rename_dir(ren1, branch1);
 891                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 892                                 clean_merge = 0;
 893                                 output("CONFLICT (rename/delete): Rename %s->%s in %s "
 894                                        "and deleted in %s",
 895                                        ren1_src, ren1_dst, branch1,
 896                                        branch2);
 897                                 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 898                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 899                                 const char *new_path;
 900                                 clean_merge = 0;
 901                                 try_merge = 1;
 902                                 output("CONFLICT (rename/add): Rename %s->%s in %s. "
 903                                        "%s added in %s",
 904                                        ren1_src, ren1_dst, branch1,
 905                                        ren1_dst, branch2);
 906                                 new_path = unique_path(ren1_dst, branch2);
 907                                 output("Adding as %s instead", new_path);
 908                                 update_file(0, dst_other.sha1, dst_other.mode, new_path);
 909                         } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
 910                                 ren2 = item->util;
 911                                 clean_merge = 0;
 912                                 ren2->processed = 1;
 913                                 output("CONFLICT (rename/rename): Rename %s->%s in %s. "
 914                                        "Rename %s->%s in %s",
 915                                        ren1_src, ren1_dst, branch1,
 916                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
 917                                 conflict_rename_rename_2(ren1, branch1, ren2, branch2);
 918                         } else
 919                                 try_merge = 1;
 920
 921                         if (try_merge) {
 922                                 struct diff_filespec *o, *a, *b;
 923                                 struct merge_file_info mfi;
 924                                 src_other.path = (char *)ren1_src;
 925
 926                                 o = ren1->pair->one;
 927                                 if (a_renames == renames1) {
 928                                         a = ren1->pair->two;
 929                                         b = &src_other;
 930                                 } else {
 931                                         b = ren1->pair->two;
 932                                         a = &src_other;
 933                                 }
 934                                 mfi = merge_file(o, a, b,
 935                                                 a_branch, b_branch);
 936
 937                                 if (mfi.merge || !mfi.clean)
 938                                         output("Renaming %s => %s", ren1_src, ren1_dst);
 939                                 if (mfi.merge)
 940                                         output("Auto-merging %s", ren1_dst);
 941                                 if (!mfi.clean) {
 942                                         output("CONFLICT (rename/modify): Merge conflict in %s",
 943                                                ren1_dst);
 944                                         clean_merge = 0;
 945
 946                                         if (!index_only)
 947                                                 update_stages(ren1_dst,
 948                                                                 o, a, b, 1);
 949                                 }
 950                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 951                         }
 952                 }
 953         }
 954         path_list_clear(&a_by_dst, 0);
 955         path_list_clear(&b_by_dst, 0);
 956
 957         if (cache_dirty)
 958                 flush_cache();
 959         return clean_merge;
 960 }
 961
 962 static unsigned char *has_sha(const unsigned char *sha)
 963 {
 964         return memcmp(sha, null_sha1, 20) == 0 ? NULL: (unsigned char *)sha;
 965 }
 966
 967 /* Per entry merge function */
 968 static int process_entry(const char *path, struct stage_data *entry,
 969                          const char *branch1,
 970                          const char *branch2)
 971 {
 972         /*
 973         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
 974         print_index_entry("\tpath: ", entry);
 975         */
 976         int clean_merge = 1;
 977         unsigned char *o_sha = has_sha(entry->stages[1].sha);
 978         unsigned char *a_sha = has_sha(entry->stages[2].sha);
 979         unsigned char *b_sha = has_sha(entry->stages[3].sha);
 980         unsigned o_mode = entry->stages[1].mode;
 981         unsigned a_mode = entry->stages[2].mode;
 982         unsigned b_mode = entry->stages[3].mode;
 983
 984         if (o_sha && (!a_sha || !b_sha)) {
 985                 /* Case A: Deleted in one */
 986                 if ((!a_sha && !b_sha) ||
 987                     (sha_eq(a_sha, o_sha) && !b_sha) ||
 988                     (!a_sha && sha_eq(b_sha, o_sha))) {
 989                         /* Deleted in both or deleted in one and
 990                          * unchanged in the other */
 991                         if (a_sha)
 992                                 output("Removing %s", path);
 993                         remove_file(1, path);
 994                 } else {
 995                         /* Deleted in one and changed in the other */
 996                         clean_merge = 0;
 997                         if (!a_sha) {
 998                                 output("CONFLICT (delete/modify): %s deleted in %s "
 999                                        "and modified in %s. Version %s of %s left in tree.",
1000                                        path, branch1,
1001                                        branch2, branch2, path);
1002                                 update_file(0, b_sha, b_mode, path);
1003                         } else {
1004                                 output("CONFLICT (delete/modify): %s deleted in %s "
1005                                        "and modified in %s. Version %s of %s left in tree.",
1006                                        path, branch2,
1007                                        branch1, branch1, path);
1008                                 update_file(0, a_sha, a_mode, path);
1009                         }
1010                 }
1011
1012         } else if ((!o_sha && a_sha && !b_sha) ||
1013                    (!o_sha && !a_sha && b_sha)) {
1014                 /* Case B: Added in one. */
1015                 const char *add_branch;
1016                 const char *other_branch;
1017                 unsigned mode;
1018                 const unsigned char *sha;
1019                 const char *conf;
1020
1021                 if (a_sha) {
1022                         add_branch = branch1;
1023                         other_branch = branch2;
1024                         mode = a_mode;
1025                         sha = a_sha;
1026                         conf = "file/directory";
1027                 } else {
1028                         add_branch = branch2;
1029                         other_branch = branch1;
1030                         mode = b_mode;
1031                         sha = b_sha;
1032                         conf = "directory/file";
1033                 }
1034                 if (path_list_has_path(&current_directory_set, path)) {
1035                         const char *new_path = unique_path(path, add_branch);
1036                         clean_merge = 0;
1037                         output("CONFLICT (%s): There is a directory with name %s in %s. "
1038                                "Adding %s as %s",
1039                                conf, path, other_branch, path, new_path);
1040                         remove_file(0, path);
1041                         update_file(0, sha, mode, new_path);
1042                 } else {
1043                         output("Adding %s", path);
1044                         update_file(1, sha, mode, path);
1045                 }
1046         } else if (!o_sha && a_sha && b_sha) {
1047                 /* Case C: Added in both (check for same permissions). */
1048                 if (sha_eq(a_sha, b_sha)) {
1049                         if (a_mode != b_mode) {
1050                                 clean_merge = 0;
1051                                 output("CONFLICT: File %s added identically in both branches, "
1052                                        "but permissions conflict %06o->%06o",
1053                                        path, a_mode, b_mode);
1054                                 output("CONFLICT: adding with permission: %06o", a_mode);
1055                                 update_file(0, a_sha, a_mode, path);
1056                         } else {
1057                                 /* This case is handled by git-read-tree */
1058                                 assert(0 && "This case must be handled by git-read-tree");
1059                         }
1060                 } else {
1061                         const char *new_path1, *new_path2;
1062                         clean_merge = 0;
1063                         new_path1 = unique_path(path, branch1);
1064                         new_path2 = unique_path(path, branch2);
1065                         output("CONFLICT (add/add): File %s added non-identically "
1066                                "in both branches. Adding as %s and %s instead.",
1067                                path, new_path1, new_path2);
1068                         remove_file(0, path);
1069                         update_file(0, a_sha, a_mode, new_path1);
1070                         update_file(0, b_sha, b_mode, new_path2);
1071                 }
1072
1073         } else if (o_sha && a_sha && b_sha) {
1074                 /* case D: Modified in both, but differently. */
1075                 struct merge_file_info mfi;
1076                 struct diff_filespec o, a, b;
1077
1078                 output("Auto-merging %s", path);
1079                 o.path = a.path = b.path = (char *)path;
1080                 memcpy(o.sha1, o_sha, 20);
1081                 o.mode = o_mode;
1082                 memcpy(a.sha1, a_sha, 20);
1083                 a.mode = a_mode;
1084                 memcpy(b.sha1, b_sha, 20);
1085                 b.mode = b_mode;
1086
1087                 mfi = merge_file(&o, &a, &b,
1088                                  branch1, branch2);
1089
1090                 if (mfi.clean)
1091                         update_file(1, mfi.sha, mfi.mode, path);
1092                 else {
1093                         clean_merge = 0;
1094                         output("CONFLICT (content): Merge conflict in %s", path);
1095
1096                         if (index_only)
1097                                 update_file(0, mfi.sha, mfi.mode, path);
1098                         else
1099                                 update_file_flags(mfi.sha, mfi.mode, path,
1100                                               0 /* update_cache */, 1 /* update_working_directory */);
1101                 }
1102         } else
1103                 die("Fatal merge failure, shouldn't happen.");
1104
1105         if (cache_dirty)
1106                 flush_cache();
1107
1108         return clean_merge;
1109 }
1110
1111 static int merge_trees(struct tree *head,
1112                        struct tree *merge,
1113                        struct tree *common,
1114                        const char *branch1,
1115                        const char *branch2,
1116                        struct tree **result)
1117 {
1118         int code, clean;
1119         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1120                 output("Already uptodate!");
1121                 *result = head;
1122                 return 1;
1123         }
1124
1125         code = git_merge_trees(index_only ? "-i": "-u", common, head, merge);
1126
1127         if (code != 0)
1128                 die("merging of trees %s and %s failed",
1129                     sha1_to_hex(head->object.sha1),
1130                     sha1_to_hex(merge->object.sha1));
1131
1132         *result = git_write_tree();
1133
1134         if (!*result) {
1135                 struct path_list *entries, *re_head, *re_merge;
1136                 int i;
1137                 path_list_clear(&current_file_set, 1);
1138                 path_list_clear(&current_directory_set, 1);
1139                 get_files_dirs(head);
1140                 get_files_dirs(merge);
1141
1142                 entries = get_unmerged();
1143                 re_head  = get_renames(head, common, head, merge, entries);
1144                 re_merge = get_renames(merge, common, head, merge, entries);
1145                 clean = process_renames(re_head, re_merge,
1146                                 branch1, branch2);
1147                 for (i = 0; i < entries->nr; i++) {
1148                         const char *path = entries->items[i].path;
1149                         struct stage_data *e = entries->items[i].util;
1150                         if (e->processed)
1151                                 continue;
1152                         if (!process_entry(path, e, branch1, branch2))
1153                                 clean = 0;
1154                 }
1155
1156                 path_list_clear(re_merge, 0);
1157                 path_list_clear(re_head, 0);
1158                 path_list_clear(entries, 1);
1159
1160                 if (clean || index_only)
1161                         *result = git_write_tree();
1162                 else
1163                         *result = NULL;
1164         } else {
1165                 clean = 1;
1166                 printf("merging of trees %s and %s resulted in %s\n",
1167                        sha1_to_hex(head->object.sha1),
1168                        sha1_to_hex(merge->object.sha1),
1169                        sha1_to_hex((*result)->object.sha1));
1170         }
1171
1172         return clean;
1173 }
1174
1175 /*
1176  * Merge the commits h1 and h2, return the resulting virtual
1177  * commit object and a flag indicating the cleaness of the merge.
1178  */
1179 static
1180 int merge(struct commit *h1,
1181                           struct commit *h2,
1182                           const char *branch1,
1183                           const char *branch2,
1184                           int call_depth /* =0 */,
1185                           struct commit *ancestor /* =None */,
1186                           struct commit **result)
1187 {
1188         struct commit_list *ca = NULL, *iter;
1189         struct commit *merged_common_ancestors;
1190         struct tree *mrtree;
1191         int clean;
1192
1193         output("Merging:");
1194         output_commit_title(h1);
1195         output_commit_title(h2);
1196
1197         if (ancestor)
1198                 commit_list_insert(ancestor, &ca);
1199         else
1200                 ca = get_merge_bases(h1, h2, 1);
1201
1202         output("found %u common ancestor(s):", commit_list_count(ca));
1203         for (iter = ca; iter; iter = iter->next)
1204                 output_commit_title(iter->item);
1205
1206         merged_common_ancestors = pop_commit(&ca);
1207
1208         for (iter = ca; iter; iter = iter->next) {
1209                 output_indent = call_depth + 1;
1210                 /*
1211                  * When the merge fails, the result contains files
1212                  * with conflict markers. The cleanness flag is
1213                  * ignored, it was never acutally used, as result of
1214                  * merge_trees has always overwritten it: the commited
1215                  * "conflicts" were already resolved.
1216                  */
1217                 merge(merged_common_ancestors, iter->item,
1218                       "Temporary merge branch 1",
1219                       "Temporary merge branch 2",
1220                       call_depth + 1,
1221                       NULL,
1222                       &merged_common_ancestors);
1223                 output_indent = call_depth;
1224
1225                 if (!merged_common_ancestors)
1226                         die("merge returned no commit");
1227         }
1228
1229         if (call_depth == 0) {
1230                 setup_index(0 /* $GIT_DIR/index */);
1231                 index_only = 0;
1232         } else {
1233                 setup_index(1 /* temporary index */);
1234                 git_read_tree(h1->tree);
1235                 index_only = 1;
1236         }
1237
1238         clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1239                             branch1, branch2, &mrtree);
1240
1241         if (!ancestor && (clean || index_only)) {
1242                 *result = make_virtual_commit(mrtree, "merged tree");
1243                 commit_list_insert(h1, &(*result)->parents);
1244                 commit_list_insert(h2, &(*result)->parents->next);
1245         } else
1246                 *result = NULL;
1247
1248         return clean;
1249 }
1250
1251 static struct commit *get_ref(const char *ref)
1252 {
1253         unsigned char sha1[20];
1254         struct object *object;
1255
1256         if (get_sha1(ref, sha1))
1257                 die("Could not resolve ref '%s'", ref);
1258         object = deref_tag(parse_object(sha1), ref, strlen(ref));
1259         if (object->type != OBJ_COMMIT)
1260                 return NULL;
1261         if (parse_commit((struct commit *)object))
1262                 die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1263         return (struct commit *)object;
1264 }
1265
1266 int main(int argc, char *argv[])
1267 {
1268         static const char *bases[2];
1269         static unsigned bases_count = 0;
1270         int i, clean;
1271         const char *branch1, *branch2;
1272         struct commit *result, *h1, *h2;
1273
1274         original_index_file = getenv("GIT_INDEX_FILE");
1275
1276         if (!original_index_file)
1277                 original_index_file = strdup(git_path("index"));
1278
1279         temporary_index_file = strdup(git_path("mrg-rcrsv-tmp-idx"));
1280
1281         if (argc < 4)
1282                 die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1283
1284         for (i = 1; i < argc; ++i) {
1285                 if (!strcmp(argv[i], "--"))
1286                         break;
1287                 if (bases_count < sizeof(bases)/sizeof(*bases))
1288                         bases[bases_count++] = argv[i];
1289         }
1290         if (argc - i != 3) /* "--" "<head>" "<remote>" */
1291                 die("Not handling anything other than two heads merge.");
1292
1293         branch1 = argv[++i];
1294         branch2 = argv[++i];
1295         printf("Merging %s with %s\n", branch1, branch2);
1296
1297         h1 = get_ref(branch1);
1298         h2 = get_ref(branch2);
1299
1300         if (bases_count == 1) {
1301                 struct commit *ancestor = get_ref(bases[0]);
1302                 clean = merge(h1, h2, branch1, branch2, 0, ancestor, &result);
1303         } else
1304                 clean = merge(h1, h2, branch1, branch2, 0, NULL, &result);
1305
1306         if (cache_dirty)
1307                 flush_cache();
1308
1309         return clean ? 0: 1;
1310 }
1311
1312 /*
1313 vim: sw=8 noet
1314 */