merge-recursive.con commit git-svn: prevent dcommitting if the index is dirty. (c8cfa3e)
   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
  21static int subtree_merge;
  22
  23static 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
  43static 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
  51static 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 */
  67static 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 */
  78struct stage_data
  79{
  80        struct
  81        {
  82                unsigned mode;
  83                unsigned char sha[20];
  84        } stages[4];
  85        unsigned processed:1;
  86};
  87
  88struct output_buffer
  89{
  90        struct output_buffer *next;
  91        char *str;
  92};
  93
  94static struct path_list current_file_set = {NULL, 0, 0, 1};
  95static struct path_list current_directory_set = {NULL, 0, 0, 1};
  96
  97static int call_depth = 0;
  98static int verbosity = 2;
  99static int rename_limit = -1;
 100static int buffer_output = 1;
 101static struct output_buffer *output_list, *output_end;
 102
 103static int show (int v)
 104{
 105        return (!call_depth && verbosity >= v) || verbosity >= 5;
 106}
 107
 108static void output(int v, const char *fmt, ...)
 109{
 110        va_list args;
 111        va_start(args, fmt);
 112        if (buffer_output && show(v)) {
 113                struct output_buffer *b = xmalloc(sizeof(*b));
 114                nfvasprintf(&b->str, fmt, args);
 115                b->next = NULL;
 116                if (output_end)
 117                        output_end->next = b;
 118                else
 119                        output_list = b;
 120                output_end = b;
 121        } else if (show(v)) {
 122                int i;
 123                for (i = call_depth; i--;)
 124                        fputs("  ", stdout);
 125                vfprintf(stdout, fmt, args);
 126                fputc('\n', stdout);
 127        }
 128        va_end(args);
 129}
 130
 131static void flush_output(void)
 132{
 133        struct output_buffer *b, *n;
 134        for (b = output_list; b; b = n) {
 135                int i;
 136                for (i = call_depth; i--;)
 137                        fputs("  ", stdout);
 138                fputs(b->str, stdout);
 139                fputc('\n', stdout);
 140                n = b->next;
 141                free(b->str);
 142                free(b);
 143        }
 144        output_list = NULL;
 145        output_end = NULL;
 146}
 147
 148static void output_commit_title(struct commit *commit)
 149{
 150        int i;
 151        flush_output();
 152        for (i = call_depth; i--;)
 153                fputs("  ", stdout);
 154        if (commit->util)
 155                printf("virtual %s\n", (char *)commit->util);
 156        else {
 157                printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 158                if (parse_commit(commit) != 0)
 159                        printf("(bad commit)\n");
 160                else {
 161                        const char *s;
 162                        int len;
 163                        for (s = commit->buffer; *s; s++)
 164                                if (*s == '\n' && s[1] == '\n') {
 165                                        s += 2;
 166                                        break;
 167                                }
 168                        for (len = 0; s[len] && '\n' != s[len]; len++)
 169                                ; /* do nothing */
 170                        printf("%.*s\n", len, s);
 171                }
 172        }
 173}
 174
 175static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 176                const char *path, int stage, int refresh, int options)
 177{
 178        struct cache_entry *ce;
 179        ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 180        if (!ce)
 181                return error("addinfo_cache failed for path '%s'", path);
 182        return add_cache_entry(ce, options);
 183}
 184
 185/*
 186 * This is a global variable which is used in a number of places but
 187 * only written to in the 'merge' function.
 188 *
 189 * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
 190 *                       don't update the working directory.
 191 *               0    => Leave unmerged entries in the cache and update
 192 *                       the working directory.
 193 */
 194static int index_only = 0;
 195
 196static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 197{
 198        parse_tree(tree);
 199        init_tree_desc(desc, tree->buffer, tree->size);
 200}
 201
 202static int git_merge_trees(int index_only,
 203                           struct tree *common,
 204                           struct tree *head,
 205                           struct tree *merge)
 206{
 207        int rc;
 208        struct tree_desc t[3];
 209        struct unpack_trees_options opts;
 210
 211        memset(&opts, 0, sizeof(opts));
 212        if (index_only)
 213                opts.index_only = 1;
 214        else
 215                opts.update = 1;
 216        opts.merge = 1;
 217        opts.head_idx = 2;
 218        opts.fn = threeway_merge;
 219
 220        init_tree_desc_from_tree(t+0, common);
 221        init_tree_desc_from_tree(t+1, head);
 222        init_tree_desc_from_tree(t+2, merge);
 223
 224        rc = unpack_trees(3, t, &opts);
 225        cache_tree_free(&active_cache_tree);
 226        return rc;
 227}
 228
 229static int unmerged_index(void)
 230{
 231        int i;
 232        for (i = 0; i < active_nr; i++) {
 233                struct cache_entry *ce = active_cache[i];
 234                if (ce_stage(ce))
 235                        return 1;
 236        }
 237        return 0;
 238}
 239
 240static struct tree *git_write_tree(void)
 241{
 242        struct tree *result = NULL;
 243
 244        if (unmerged_index()) {
 245                int i;
 246                output(0, "There are unmerged index entries:");
 247                for (i = 0; i < active_nr; i++) {
 248                        struct cache_entry *ce = active_cache[i];
 249                        if (ce_stage(ce))
 250                                output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
 251                }
 252                return NULL;
 253        }
 254
 255        if (!active_cache_tree)
 256                active_cache_tree = cache_tree();
 257
 258        if (!cache_tree_fully_valid(active_cache_tree) &&
 259            cache_tree_update(active_cache_tree,
 260                              active_cache, active_nr, 0, 0) < 0)
 261                die("error building trees");
 262
 263        result = lookup_tree(active_cache_tree->sha1);
 264
 265        return result;
 266}
 267
 268static int save_files_dirs(const unsigned char *sha1,
 269                const char *base, int baselen, const char *path,
 270                unsigned int mode, int stage)
 271{
 272        int len = strlen(path);
 273        char *newpath = xmalloc(baselen + len + 1);
 274        memcpy(newpath, base, baselen);
 275        memcpy(newpath + baselen, path, len);
 276        newpath[baselen + len] = '\0';
 277
 278        if (S_ISDIR(mode))
 279                path_list_insert(newpath, &current_directory_set);
 280        else
 281                path_list_insert(newpath, &current_file_set);
 282        free(newpath);
 283
 284        return READ_TREE_RECURSIVE;
 285}
 286
 287static int get_files_dirs(struct tree *tree)
 288{
 289        int n;
 290        if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
 291                return 0;
 292        n = current_file_set.nr + current_directory_set.nr;
 293        return n;
 294}
 295
 296/*
 297 * Returns a index_entry instance which doesn't have to correspond to
 298 * a real cache entry in Git's index.
 299 */
 300static struct stage_data *insert_stage_data(const char *path,
 301                struct tree *o, struct tree *a, struct tree *b,
 302                struct path_list *entries)
 303{
 304        struct path_list_item *item;
 305        struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 306        get_tree_entry(o->object.sha1, path,
 307                        e->stages[1].sha, &e->stages[1].mode);
 308        get_tree_entry(a->object.sha1, path,
 309                        e->stages[2].sha, &e->stages[2].mode);
 310        get_tree_entry(b->object.sha1, path,
 311                        e->stages[3].sha, &e->stages[3].mode);
 312        item = path_list_insert(path, entries);
 313        item->util = e;
 314        return e;
 315}
 316
 317/*
 318 * Create a dictionary mapping file names to stage_data objects. The
 319 * dictionary contains one entry for every path with a non-zero stage entry.
 320 */
 321static struct path_list *get_unmerged(void)
 322{
 323        struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
 324        int i;
 325
 326        unmerged->strdup_paths = 1;
 327
 328        for (i = 0; i < active_nr; i++) {
 329                struct path_list_item *item;
 330                struct stage_data *e;
 331                struct cache_entry *ce = active_cache[i];
 332                if (!ce_stage(ce))
 333                        continue;
 334
 335                item = path_list_lookup(ce->name, unmerged);
 336                if (!item) {
 337                        item = path_list_insert(ce->name, unmerged);
 338                        item->util = xcalloc(1, sizeof(struct stage_data));
 339                }
 340                e = item->util;
 341                e->stages[ce_stage(ce)].mode = ntohl(ce->ce_mode);
 342                hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 343        }
 344
 345        return unmerged;
 346}
 347
 348struct rename
 349{
 350        struct diff_filepair *pair;
 351        struct stage_data *src_entry;
 352        struct stage_data *dst_entry;
 353        unsigned processed:1;
 354};
 355
 356/*
 357 * Get information of all renames which occurred between 'o_tree' and
 358 * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 359 * 'b_tree') to be able to associate the correct cache entries with
 360 * the rename information. 'tree' is always equal to either a_tree or b_tree.
 361 */
 362static struct path_list *get_renames(struct tree *tree,
 363                                        struct tree *o_tree,
 364                                        struct tree *a_tree,
 365                                        struct tree *b_tree,
 366                                        struct path_list *entries)
 367{
 368        int i;
 369        struct path_list *renames;
 370        struct diff_options opts;
 371
 372        renames = xcalloc(1, sizeof(struct path_list));
 373        diff_setup(&opts);
 374        opts.recursive = 1;
 375        opts.detect_rename = DIFF_DETECT_RENAME;
 376        opts.rename_limit = rename_limit;
 377        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 378        if (diff_setup_done(&opts) < 0)
 379                die("diff setup failed");
 380        diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 381        diffcore_std(&opts);
 382        for (i = 0; i < diff_queued_diff.nr; ++i) {
 383                struct path_list_item *item;
 384                struct rename *re;
 385                struct diff_filepair *pair = diff_queued_diff.queue[i];
 386                if (pair->status != 'R') {
 387                        diff_free_filepair(pair);
 388                        continue;
 389                }
 390                re = xmalloc(sizeof(*re));
 391                re->processed = 0;
 392                re->pair = pair;
 393                item = path_list_lookup(re->pair->one->path, entries);
 394                if (!item)
 395                        re->src_entry = insert_stage_data(re->pair->one->path,
 396                                        o_tree, a_tree, b_tree, entries);
 397                else
 398                        re->src_entry = item->util;
 399
 400                item = path_list_lookup(re->pair->two->path, entries);
 401                if (!item)
 402                        re->dst_entry = insert_stage_data(re->pair->two->path,
 403                                        o_tree, a_tree, b_tree, entries);
 404                else
 405                        re->dst_entry = item->util;
 406                item = path_list_insert(pair->one->path, renames);
 407                item->util = re;
 408        }
 409        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 410        diff_queued_diff.nr = 0;
 411        diff_flush(&opts);
 412        return renames;
 413}
 414
 415static int update_stages(const char *path, struct diff_filespec *o,
 416                         struct diff_filespec *a, struct diff_filespec *b,
 417                         int clear)
 418{
 419        int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 420        if (clear)
 421                if (remove_file_from_cache(path))
 422                        return -1;
 423        if (o)
 424                if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 425                        return -1;
 426        if (a)
 427                if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 428                        return -1;
 429        if (b)
 430                if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 431                        return -1;
 432        return 0;
 433}
 434
 435static int remove_path(const char *name)
 436{
 437        int ret, len;
 438        char *slash, *dirs;
 439
 440        ret = unlink(name);
 441        if (ret)
 442                return ret;
 443        len = strlen(name);
 444        dirs = xmalloc(len+1);
 445        memcpy(dirs, name, len);
 446        dirs[len] = '\0';
 447        while ((slash = strrchr(name, '/'))) {
 448                *slash = '\0';
 449                len = slash - name;
 450                if (rmdir(name) != 0)
 451                        break;
 452        }
 453        free(dirs);
 454        return ret;
 455}
 456
 457static int remove_file(int clean, const char *path, int no_wd)
 458{
 459        int update_cache = index_only || clean;
 460        int update_working_directory = !index_only && !no_wd;
 461
 462        if (update_cache) {
 463                if (remove_file_from_cache(path))
 464                        return -1;
 465        }
 466        if (update_working_directory) {
 467                unlink(path);
 468                if (errno != ENOENT || errno != EISDIR)
 469                        return -1;
 470                remove_path(path);
 471        }
 472        return 0;
 473}
 474
 475static char *unique_path(const char *path, const char *branch)
 476{
 477        char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 478        int suffix = 0;
 479        struct stat st;
 480        char *p = newpath + strlen(path);
 481        strcpy(newpath, path);
 482        *(p++) = '~';
 483        strcpy(p, branch);
 484        for (; *p; ++p)
 485                if ('/' == *p)
 486                        *p = '_';
 487        while (path_list_has_path(&current_file_set, newpath) ||
 488               path_list_has_path(&current_directory_set, newpath) ||
 489               lstat(newpath, &st) == 0)
 490                sprintf(p, "_%d", suffix++);
 491
 492        path_list_insert(newpath, &current_file_set);
 493        return newpath;
 494}
 495
 496static int mkdir_p(const char *path, unsigned long mode)
 497{
 498        /* path points to cache entries, so xstrdup before messing with it */
 499        char *buf = xstrdup(path);
 500        int result = safe_create_leading_directories(buf);
 501        free(buf);
 502        return result;
 503}
 504
 505static void flush_buffer(int fd, const char *buf, unsigned long size)
 506{
 507        while (size > 0) {
 508                long ret = write_in_full(fd, buf, size);
 509                if (ret < 0) {
 510                        /* Ignore epipe */
 511                        if (errno == EPIPE)
 512                                break;
 513                        die("merge-recursive: %s", strerror(errno));
 514                } else if (!ret) {
 515                        die("merge-recursive: disk full?");
 516                }
 517                size -= ret;
 518                buf += ret;
 519        }
 520}
 521
 522static int make_room_for_path(const char *path)
 523{
 524        int status;
 525        const char *msg = "failed to create path '%s'%s";
 526
 527        status = mkdir_p(path, 0777);
 528        if (status) {
 529                if (status == -3) {
 530                        /* something else exists */
 531                        error(msg, path, ": perhaps a D/F conflict?");
 532                        return -1;
 533                }
 534                die(msg, path, "");
 535        }
 536
 537        /* Successful unlink is good.. */
 538        if (!unlink(path))
 539                return 0;
 540        /* .. and so is no existing file */
 541        if (errno == ENOENT)
 542                return 0;
 543        /* .. but not some other error (who really cares what?) */
 544        return error(msg, path, ": perhaps a D/F conflict?");
 545}
 546
 547static void update_file_flags(const unsigned char *sha,
 548                              unsigned mode,
 549                              const char *path,
 550                              int update_cache,
 551                              int update_wd)
 552{
 553        if (index_only)
 554                update_wd = 0;
 555
 556        if (update_wd) {
 557                enum object_type type;
 558                void *buf;
 559                unsigned long size;
 560
 561                buf = read_sha1_file(sha, &type, &size);
 562                if (!buf)
 563                        die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 564                if (type != OBJ_BLOB)
 565                        die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 566
 567                if (make_room_for_path(path) < 0) {
 568                        update_wd = 0;
 569                        goto update_index;
 570                }
 571                if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 572                        int fd;
 573                        if (mode & 0100)
 574                                mode = 0777;
 575                        else
 576                                mode = 0666;
 577                        fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 578                        if (fd < 0)
 579                                die("failed to open %s: %s", path, strerror(errno));
 580                        flush_buffer(fd, buf, size);
 581                        close(fd);
 582                } else if (S_ISLNK(mode)) {
 583                        char *lnk = xmalloc(size + 1);
 584                        memcpy(lnk, buf, size);
 585                        lnk[size] = '\0';
 586                        mkdir_p(path, 0777);
 587                        unlink(path);
 588                        symlink(lnk, path);
 589                        free(lnk);
 590                } else
 591                        die("do not know what to do with %06o %s '%s'",
 592                            mode, sha1_to_hex(sha), path);
 593        }
 594 update_index:
 595        if (update_cache)
 596                add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 597}
 598
 599static void update_file(int clean,
 600                        const unsigned char *sha,
 601                        unsigned mode,
 602                        const char *path)
 603{
 604        update_file_flags(sha, mode, path, index_only || clean, !index_only);
 605}
 606
 607/* Low level file merging, update and removal */
 608
 609struct merge_file_info
 610{
 611        unsigned char sha[20];
 612        unsigned mode;
 613        unsigned clean:1,
 614                 merge:1;
 615};
 616
 617static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 618{
 619        unsigned long size;
 620        enum object_type type;
 621
 622        if (!hashcmp(sha1, null_sha1)) {
 623                mm->ptr = xstrdup("");
 624                mm->size = 0;
 625                return;
 626        }
 627
 628        mm->ptr = read_sha1_file(sha1, &type, &size);
 629        if (!mm->ptr || type != OBJ_BLOB)
 630                die("unable to read blob object %s", sha1_to_hex(sha1));
 631        mm->size = size;
 632}
 633
 634/*
 635 * Customizable low-level merge drivers support.
 636 */
 637
 638struct ll_merge_driver;
 639typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
 640                           const char *path,
 641                           mmfile_t *orig,
 642                           mmfile_t *src1, const char *name1,
 643                           mmfile_t *src2, const char *name2,
 644                           mmbuffer_t *result);
 645
 646struct ll_merge_driver {
 647        const char *name;
 648        const char *description;
 649        ll_merge_fn fn;
 650        const char *recursive;
 651        struct ll_merge_driver *next;
 652        char *cmdline;
 653};
 654
 655/*
 656 * Built-in low-levels
 657 */
 658static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
 659                           const char *path_unused,
 660                           mmfile_t *orig,
 661                           mmfile_t *src1, const char *name1,
 662                           mmfile_t *src2, const char *name2,
 663                           mmbuffer_t *result)
 664{
 665        /*
 666         * The tentative merge result is "ours" for the final round,
 667         * or common ancestor for an internal merge.  Still return
 668         * "conflicted merge" status.
 669         */
 670        mmfile_t *stolen = index_only ? orig : src1;
 671
 672        result->ptr = stolen->ptr;
 673        result->size = stolen->size;
 674        stolen->ptr = NULL;
 675        return 1;
 676}
 677
 678static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
 679                        const char *path_unused,
 680                        mmfile_t *orig,
 681                        mmfile_t *src1, const char *name1,
 682                        mmfile_t *src2, const char *name2,
 683                        mmbuffer_t *result)
 684{
 685        xpparam_t xpp;
 686
 687        if (buffer_is_binary(orig->ptr, orig->size) ||
 688            buffer_is_binary(src1->ptr, src1->size) ||
 689            buffer_is_binary(src2->ptr, src2->size)) {
 690                warning("Cannot merge binary files: %s vs. %s\n",
 691                        name1, name2);
 692                return ll_binary_merge(drv_unused, path_unused,
 693                                       orig, src1, name1,
 694                                       src2, name2,
 695                                       result);
 696        }
 697
 698        memset(&xpp, 0, sizeof(xpp));
 699        return xdl_merge(orig,
 700                         src1, name1,
 701                         src2, name2,
 702                         &xpp, XDL_MERGE_ZEALOUS,
 703                         result);
 704}
 705
 706static int ll_union_merge(const struct ll_merge_driver *drv_unused,
 707                          const char *path_unused,
 708                          mmfile_t *orig,
 709                          mmfile_t *src1, const char *name1,
 710                          mmfile_t *src2, const char *name2,
 711                          mmbuffer_t *result)
 712{
 713        char *src, *dst;
 714        long size;
 715        const int marker_size = 7;
 716
 717        int status = ll_xdl_merge(drv_unused, path_unused,
 718                                  orig, src1, NULL, src2, NULL, result);
 719        if (status <= 0)
 720                return status;
 721        size = result->size;
 722        src = dst = result->ptr;
 723        while (size) {
 724                char ch;
 725                if ((marker_size < size) &&
 726                    (*src == '<' || *src == '=' || *src == '>')) {
 727                        int i;
 728                        ch = *src;
 729                        for (i = 0; i < marker_size; i++)
 730                                if (src[i] != ch)
 731                                        goto not_a_marker;
 732                        if (src[marker_size] != '\n')
 733                                goto not_a_marker;
 734                        src += marker_size + 1;
 735                        size -= marker_size + 1;
 736                        continue;
 737                }
 738        not_a_marker:
 739                do {
 740                        ch = *src++;
 741                        *dst++ = ch;
 742                        size--;
 743                } while (ch != '\n' && size);
 744        }
 745        result->size = dst - result->ptr;
 746        return 0;
 747}
 748
 749#define LL_BINARY_MERGE 0
 750#define LL_TEXT_MERGE 1
 751#define LL_UNION_MERGE 2
 752static struct ll_merge_driver ll_merge_drv[] = {
 753        { "binary", "built-in binary merge", ll_binary_merge },
 754        { "text", "built-in 3-way text merge", ll_xdl_merge },
 755        { "union", "built-in union merge", ll_union_merge },
 756};
 757
 758static void create_temp(mmfile_t *src, char *path)
 759{
 760        int fd;
 761
 762        strcpy(path, ".merge_file_XXXXXX");
 763        fd = xmkstemp(path);
 764        if (write_in_full(fd, src->ptr, src->size) != src->size)
 765                die("unable to write temp-file");
 766        close(fd);
 767}
 768
 769/*
 770 * User defined low-level merge driver support.
 771 */
 772static int ll_ext_merge(const struct ll_merge_driver *fn,
 773                        const char *path,
 774                        mmfile_t *orig,
 775                        mmfile_t *src1, const char *name1,
 776                        mmfile_t *src2, const char *name2,
 777                        mmbuffer_t *result)
 778{
 779        char temp[3][50];
 780        char cmdbuf[2048];
 781        struct interp table[] = {
 782                { "%O" },
 783                { "%A" },
 784                { "%B" },
 785        };
 786        struct child_process child;
 787        const char *args[20];
 788        int status, fd, i;
 789        struct stat st;
 790
 791        if (fn->cmdline == NULL)
 792                die("custom merge driver %s lacks command line.", fn->name);
 793
 794        result->ptr = NULL;
 795        result->size = 0;
 796        create_temp(orig, temp[0]);
 797        create_temp(src1, temp[1]);
 798        create_temp(src2, temp[2]);
 799
 800        interp_set_entry(table, 0, temp[0]);
 801        interp_set_entry(table, 1, temp[1]);
 802        interp_set_entry(table, 2, temp[2]);
 803
 804        output(1, "merging %s using %s", path,
 805               fn->description ? fn->description : fn->name);
 806
 807        interpolate(cmdbuf, sizeof(cmdbuf), fn->cmdline, table, 3);
 808
 809        memset(&child, 0, sizeof(child));
 810        child.argv = args;
 811        args[0] = "sh";
 812        args[1] = "-c";
 813        args[2] = cmdbuf;
 814        args[3] = NULL;
 815
 816        status = run_command(&child);
 817        if (status < -ERR_RUN_COMMAND_FORK)
 818                ; /* failure in run-command */
 819        else
 820                status = -status;
 821        fd = open(temp[1], O_RDONLY);
 822        if (fd < 0)
 823                goto bad;
 824        if (fstat(fd, &st))
 825                goto close_bad;
 826        result->size = st.st_size;
 827        result->ptr = xmalloc(result->size + 1);
 828        if (read_in_full(fd, result->ptr, result->size) != result->size) {
 829                free(result->ptr);
 830                result->ptr = NULL;
 831                result->size = 0;
 832        }
 833 close_bad:
 834        close(fd);
 835 bad:
 836        for (i = 0; i < 3; i++)
 837                unlink(temp[i]);
 838        return status;
 839}
 840
 841/*
 842 * merge.default and merge.driver configuration items
 843 */
 844static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
 845static const char *default_ll_merge;
 846
 847static int read_merge_config(const char *var, const char *value)
 848{
 849        struct ll_merge_driver *fn;
 850        const char *ep, *name;
 851        int namelen;
 852
 853        if (!strcmp(var, "merge.default")) {
 854                if (value)
 855                        default_ll_merge = strdup(value);
 856                return 0;
 857        }
 858
 859        /*
 860         * We are not interested in anything but "merge.<name>.variable";
 861         * especially, we do not want to look at variables such as
 862         * "merge.summary", "merge.tool", and "merge.verbosity".
 863         */
 864        if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
 865                return 0;
 866
 867        /*
 868         * Find existing one as we might be processing merge.<name>.var2
 869         * after seeing merge.<name>.var1.
 870         */
 871        name = var + 6;
 872        namelen = ep - name;
 873        for (fn = ll_user_merge; fn; fn = fn->next)
 874                if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
 875                        break;
 876        if (!fn) {
 877                char *namebuf;
 878                fn = xcalloc(1, sizeof(struct ll_merge_driver));
 879                namebuf = xmalloc(namelen + 1);
 880                memcpy(namebuf, name, namelen);
 881                namebuf[namelen] = 0;
 882                fn->name = namebuf;
 883                fn->fn = ll_ext_merge;
 884                fn->next = NULL;
 885                *ll_user_merge_tail = fn;
 886                ll_user_merge_tail = &(fn->next);
 887        }
 888
 889        ep++;
 890
 891        if (!strcmp("name", ep)) {
 892                if (!value)
 893                        return error("%s: lacks value", var);
 894                fn->description = strdup(value);
 895                return 0;
 896        }
 897
 898        if (!strcmp("driver", ep)) {
 899                if (!value)
 900                        return error("%s: lacks value", var);
 901                /*
 902                 * merge.<name>.driver specifies the command line:
 903                 *
 904                 *      command-line
 905                 *
 906                 * The command-line will be interpolated with the following
 907                 * tokens and is given to the shell:
 908                 *
 909                 *    %O - temporary file name for the merge base.
 910                 *    %A - temporary file name for our version.
 911                 *    %B - temporary file name for the other branches' version.
 912                 *
 913                 * The external merge driver should write the results in the
 914                 * file named by %A, and signal that it has done with zero exit
 915                 * status.
 916                 */
 917                fn->cmdline = strdup(value);
 918                return 0;
 919        }
 920
 921        if (!strcmp("recursive", ep)) {
 922                if (!value)
 923                        return error("%s: lacks value", var);
 924                fn->recursive = strdup(value);
 925                return 0;
 926        }
 927
 928        return 0;
 929}
 930
 931static void initialize_ll_merge(void)
 932{
 933        if (ll_user_merge_tail)
 934                return;
 935        ll_user_merge_tail = &ll_user_merge;
 936        git_config(read_merge_config);
 937}
 938
 939static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
 940{
 941        struct ll_merge_driver *fn;
 942        const char *name;
 943        int i;
 944
 945        initialize_ll_merge();
 946
 947        if (ATTR_TRUE(merge_attr))
 948                return &ll_merge_drv[LL_TEXT_MERGE];
 949        else if (ATTR_FALSE(merge_attr))
 950                return &ll_merge_drv[LL_BINARY_MERGE];
 951        else if (ATTR_UNSET(merge_attr)) {
 952                if (!default_ll_merge)
 953                        return &ll_merge_drv[LL_TEXT_MERGE];
 954                else
 955                        name = default_ll_merge;
 956        }
 957        else
 958                name = merge_attr;
 959
 960        for (fn = ll_user_merge; fn; fn = fn->next)
 961                if (!strcmp(fn->name, name))
 962                        return fn;
 963
 964        for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
 965                if (!strcmp(ll_merge_drv[i].name, name))
 966                        return &ll_merge_drv[i];
 967
 968        /* default to the 3-way */
 969        return &ll_merge_drv[LL_TEXT_MERGE];
 970}
 971
 972static const char *git_path_check_merge(const char *path)
 973{
 974        static struct git_attr_check attr_merge_check;
 975
 976        if (!attr_merge_check.attr)
 977                attr_merge_check.attr = git_attr("merge", 5);
 978
 979        if (git_checkattr(path, 1, &attr_merge_check))
 980                return NULL;
 981        return attr_merge_check.value;
 982}
 983
 984static int ll_merge(mmbuffer_t *result_buf,
 985                    struct diff_filespec *o,
 986                    struct diff_filespec *a,
 987                    struct diff_filespec *b,
 988                    const char *branch1,
 989                    const char *branch2)
 990{
 991        mmfile_t orig, src1, src2;
 992        char *name1, *name2;
 993        int merge_status;
 994        const char *ll_driver_name;
 995        const struct ll_merge_driver *driver;
 996
 997        name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 998        name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 999
1000        fill_mm(o->sha1, &orig);
1001        fill_mm(a->sha1, &src1);
1002        fill_mm(b->sha1, &src2);
1003
1004        ll_driver_name = git_path_check_merge(a->path);
1005        driver = find_ll_merge_driver(ll_driver_name);
1006
1007        if (index_only && driver->recursive)
1008                driver = find_ll_merge_driver(driver->recursive);
1009        merge_status = driver->fn(driver, a->path,
1010                                  &orig, &src1, name1, &src2, name2,
1011                                  result_buf);
1012
1013        free(name1);
1014        free(name2);
1015        free(orig.ptr);
1016        free(src1.ptr);
1017        free(src2.ptr);
1018        return merge_status;
1019}
1020
1021static struct merge_file_info merge_file(struct diff_filespec *o,
1022                struct diff_filespec *a, struct diff_filespec *b,
1023                const char *branch1, const char *branch2)
1024{
1025        struct merge_file_info result;
1026        result.merge = 0;
1027        result.clean = 1;
1028
1029        if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
1030                result.clean = 0;
1031                if (S_ISREG(a->mode)) {
1032                        result.mode = a->mode;
1033                        hashcpy(result.sha, a->sha1);
1034                } else {
1035                        result.mode = b->mode;
1036                        hashcpy(result.sha, b->sha1);
1037                }
1038        } else {
1039                if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
1040                        result.merge = 1;
1041
1042                result.mode = a->mode == o->mode ? b->mode: a->mode;
1043
1044                if (sha_eq(a->sha1, o->sha1))
1045                        hashcpy(result.sha, b->sha1);
1046                else if (sha_eq(b->sha1, o->sha1))
1047                        hashcpy(result.sha, a->sha1);
1048                else if (S_ISREG(a->mode)) {
1049                        mmbuffer_t result_buf;
1050                        int merge_status;
1051
1052                        merge_status = ll_merge(&result_buf, o, a, b,
1053                                                branch1, branch2);
1054
1055                        if ((merge_status < 0) || !result_buf.ptr)
1056                                die("Failed to execute internal merge");
1057
1058                        if (write_sha1_file(result_buf.ptr, result_buf.size,
1059                                            blob_type, result.sha))
1060                                die("Unable to add %s to database",
1061                                    a->path);
1062
1063                        free(result_buf.ptr);
1064                        result.clean = (merge_status == 0);
1065                } else {
1066                        if (!(S_ISLNK(a->mode) || S_ISLNK(b->mode)))
1067                                die("cannot merge modes?");
1068
1069                        hashcpy(result.sha, a->sha1);
1070
1071                        if (!sha_eq(a->sha1, b->sha1))
1072                                result.clean = 0;
1073                }
1074        }
1075
1076        return result;
1077}
1078
1079static void conflict_rename_rename(struct rename *ren1,
1080                                   const char *branch1,
1081                                   struct rename *ren2,
1082                                   const char *branch2)
1083{
1084        char *del[2];
1085        int delp = 0;
1086        const char *ren1_dst = ren1->pair->two->path;
1087        const char *ren2_dst = ren2->pair->two->path;
1088        const char *dst_name1 = ren1_dst;
1089        const char *dst_name2 = ren2_dst;
1090        if (path_list_has_path(&current_directory_set, ren1_dst)) {
1091                dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
1092                output(1, "%s is a directory in %s added as %s instead",
1093                       ren1_dst, branch2, dst_name1);
1094                remove_file(0, ren1_dst, 0);
1095        }
1096        if (path_list_has_path(&current_directory_set, ren2_dst)) {
1097                dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
1098                output(1, "%s is a directory in %s added as %s instead",
1099                       ren2_dst, branch1, dst_name2);
1100                remove_file(0, ren2_dst, 0);
1101        }
1102        if (index_only) {
1103                remove_file_from_cache(dst_name1);
1104                remove_file_from_cache(dst_name2);
1105                /*
1106                 * Uncomment to leave the conflicting names in the resulting tree
1107                 *
1108                 * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
1109                 * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
1110                 */
1111        } else {
1112                update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
1113                update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
1114        }
1115        while (delp--)
1116                free(del[delp]);
1117}
1118
1119static void conflict_rename_dir(struct rename *ren1,
1120                                const char *branch1)
1121{
1122        char *new_path = unique_path(ren1->pair->two->path, branch1);
1123        output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
1124        remove_file(0, ren1->pair->two->path, 0);
1125        update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
1126        free(new_path);
1127}
1128
1129static void conflict_rename_rename_2(struct rename *ren1,
1130                                     const char *branch1,
1131                                     struct rename *ren2,
1132                                     const char *branch2)
1133{
1134        char *new_path1 = unique_path(ren1->pair->two->path, branch1);
1135        char *new_path2 = unique_path(ren2->pair->two->path, branch2);
1136        output(1, "Renamed %s to %s and %s to %s instead",
1137               ren1->pair->one->path, new_path1,
1138               ren2->pair->one->path, new_path2);
1139        remove_file(0, ren1->pair->two->path, 0);
1140        update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
1141        update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
1142        free(new_path2);
1143        free(new_path1);
1144}
1145
1146static int process_renames(struct path_list *a_renames,
1147                           struct path_list *b_renames,
1148                           const char *a_branch,
1149                           const char *b_branch)
1150{
1151        int clean_merge = 1, i, j;
1152        struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
1153        const struct rename *sre;
1154
1155        for (i = 0; i < a_renames->nr; i++) {
1156                sre = a_renames->items[i].util;
1157                path_list_insert(sre->pair->two->path, &a_by_dst)->util
1158                        = sre->dst_entry;
1159        }
1160        for (i = 0; i < b_renames->nr; i++) {
1161                sre = b_renames->items[i].util;
1162                path_list_insert(sre->pair->two->path, &b_by_dst)->util
1163                        = sre->dst_entry;
1164        }
1165
1166        for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1167                int compare;
1168                char *src;
1169                struct path_list *renames1, *renames2, *renames2Dst;
1170                struct rename *ren1 = NULL, *ren2 = NULL;
1171                const char *branch1, *branch2;
1172                const char *ren1_src, *ren1_dst;
1173
1174                if (i >= a_renames->nr) {
1175                        compare = 1;
1176                        ren2 = b_renames->items[j++].util;
1177                } else if (j >= b_renames->nr) {
1178                        compare = -1;
1179                        ren1 = a_renames->items[i++].util;
1180                } else {
1181                        compare = strcmp(a_renames->items[i].path,
1182                                        b_renames->items[j].path);
1183                        if (compare <= 0)
1184                                ren1 = a_renames->items[i++].util;
1185                        if (compare >= 0)
1186                                ren2 = b_renames->items[j++].util;
1187                }
1188
1189                /* TODO: refactor, so that 1/2 are not needed */
1190                if (ren1) {
1191                        renames1 = a_renames;
1192                        renames2 = b_renames;
1193                        renames2Dst = &b_by_dst;
1194                        branch1 = a_branch;
1195                        branch2 = b_branch;
1196                } else {
1197                        struct rename *tmp;
1198                        renames1 = b_renames;
1199                        renames2 = a_renames;
1200                        renames2Dst = &a_by_dst;
1201                        branch1 = b_branch;
1202                        branch2 = a_branch;
1203                        tmp = ren2;
1204                        ren2 = ren1;
1205                        ren1 = tmp;
1206                }
1207                src = ren1->pair->one->path;
1208
1209                ren1->dst_entry->processed = 1;
1210                ren1->src_entry->processed = 1;
1211
1212                if (ren1->processed)
1213                        continue;
1214                ren1->processed = 1;
1215
1216                ren1_src = ren1->pair->one->path;
1217                ren1_dst = ren1->pair->two->path;
1218
1219                if (ren2) {
1220                        const char *ren2_src = ren2->pair->one->path;
1221                        const char *ren2_dst = ren2->pair->two->path;
1222                        /* Renamed in 1 and renamed in 2 */
1223                        if (strcmp(ren1_src, ren2_src) != 0)
1224                                die("ren1.src != ren2.src");
1225                        ren2->dst_entry->processed = 1;
1226                        ren2->processed = 1;
1227                        if (strcmp(ren1_dst, ren2_dst) != 0) {
1228                                clean_merge = 0;
1229                                output(1, "CONFLICT (rename/rename): "
1230                                       "Rename \"%s\"->\"%s\" in branch \"%s\" "
1231                                       "rename \"%s\"->\"%s\" in \"%s\"%s",
1232                                       src, ren1_dst, branch1,
1233                                       src, ren2_dst, branch2,
1234                                       index_only ? " (left unresolved)": "");
1235                                if (index_only) {
1236                                        remove_file_from_cache(src);
1237                                        update_file(0, ren1->pair->one->sha1,
1238                                                    ren1->pair->one->mode, src);
1239                                }
1240                                conflict_rename_rename(ren1, branch1, ren2, branch2);
1241                        } else {
1242                                struct merge_file_info mfi;
1243                                remove_file(1, ren1_src, 1);
1244                                mfi = merge_file(ren1->pair->one,
1245                                                 ren1->pair->two,
1246                                                 ren2->pair->two,
1247                                                 branch1,
1248                                                 branch2);
1249                                if (mfi.merge || !mfi.clean)
1250                                        output(1, "Renamed %s->%s", src, ren1_dst);
1251
1252                                if (mfi.merge)
1253                                        output(2, "Auto-merged %s", ren1_dst);
1254
1255                                if (!mfi.clean) {
1256                                        output(1, "CONFLICT (content): merge conflict in %s",
1257                                               ren1_dst);
1258                                        clean_merge = 0;
1259
1260                                        if (!index_only)
1261                                                update_stages(ren1_dst,
1262                                                              ren1->pair->one,
1263                                                              ren1->pair->two,
1264                                                              ren2->pair->two,
1265                                                              1 /* clear */);
1266                                }
1267                                update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1268                        }
1269                } else {
1270                        /* Renamed in 1, maybe changed in 2 */
1271                        struct path_list_item *item;
1272                        /* we only use sha1 and mode of these */
1273                        struct diff_filespec src_other, dst_other;
1274                        int try_merge, stage = a_renames == renames1 ? 3: 2;
1275
1276                        remove_file(1, ren1_src, index_only || stage == 3);
1277
1278                        hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
1279                        src_other.mode = ren1->src_entry->stages[stage].mode;
1280                        hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
1281                        dst_other.mode = ren1->dst_entry->stages[stage].mode;
1282
1283                        try_merge = 0;
1284
1285                        if (path_list_has_path(&current_directory_set, ren1_dst)) {
1286                                clean_merge = 0;
1287                                output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
1288                                       " directory %s added in %s",
1289                                       ren1_src, ren1_dst, branch1,
1290                                       ren1_dst, branch2);
1291                                conflict_rename_dir(ren1, branch1);
1292                        } else if (sha_eq(src_other.sha1, null_sha1)) {
1293                                clean_merge = 0;
1294                                output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
1295                                       "and deleted in %s",
1296                                       ren1_src, ren1_dst, branch1,
1297                                       branch2);
1298                                update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
1299                        } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1300                                const char *new_path;
1301                                clean_merge = 0;
1302                                try_merge = 1;
1303                                output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
1304                                       "%s added in %s",
1305                                       ren1_src, ren1_dst, branch1,
1306                                       ren1_dst, branch2);
1307                                new_path = unique_path(ren1_dst, branch2);
1308                                output(1, "Added as %s instead", new_path);
1309                                update_file(0, dst_other.sha1, dst_other.mode, new_path);
1310                        } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
1311                                ren2 = item->util;
1312                                clean_merge = 0;
1313                                ren2->processed = 1;
1314                                output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
1315                                       "Renamed %s->%s in %s",
1316                                       ren1_src, ren1_dst, branch1,
1317                                       ren2->pair->one->path, ren2->pair->two->path, branch2);
1318                                conflict_rename_rename_2(ren1, branch1, ren2, branch2);
1319                        } else
1320                                try_merge = 1;
1321
1322                        if (try_merge) {
1323                                struct diff_filespec *o, *a, *b;
1324                                struct merge_file_info mfi;
1325                                src_other.path = (char *)ren1_src;
1326
1327                                o = ren1->pair->one;
1328                                if (a_renames == renames1) {
1329                                        a = ren1->pair->two;
1330                                        b = &src_other;
1331                                } else {
1332                                        b = ren1->pair->two;
1333                                        a = &src_other;
1334                                }
1335                                mfi = merge_file(o, a, b,
1336                                                a_branch, b_branch);
1337
1338                                if (mfi.clean &&
1339                                    sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1340                                    mfi.mode == ren1->pair->two->mode)
1341                                        /*
1342                                         * This messaged is part of
1343                                         * t6022 test. If you change
1344                                         * it update the test too.
1345                                         */
1346                                        output(3, "Skipped %s (merged same as existing)", ren1_dst);
1347                                else {
1348                                        if (mfi.merge || !mfi.clean)
1349                                                output(1, "Renamed %s => %s", ren1_src, ren1_dst);
1350                                        if (mfi.merge)
1351                                                output(2, "Auto-merged %s", ren1_dst);
1352                                        if (!mfi.clean) {
1353                                                output(1, "CONFLICT (rename/modify): Merge conflict in %s",
1354                                                       ren1_dst);
1355                                                clean_merge = 0;
1356
1357                                                if (!index_only)
1358                                                        update_stages(ren1_dst,
1359                                                                      o, a, b, 1);
1360                                        }
1361                                        update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1362                                }
1363                        }
1364                }
1365        }
1366        path_list_clear(&a_by_dst, 0);
1367        path_list_clear(&b_by_dst, 0);
1368
1369        return clean_merge;
1370}
1371
1372static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1373{
1374        return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1375}
1376
1377/* Per entry merge function */
1378static int process_entry(const char *path, struct stage_data *entry,
1379                         const char *branch1,
1380                         const char *branch2)
1381{
1382        /*
1383        printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1384        print_index_entry("\tpath: ", entry);
1385        */
1386        int clean_merge = 1;
1387        unsigned o_mode = entry->stages[1].mode;
1388        unsigned a_mode = entry->stages[2].mode;
1389        unsigned b_mode = entry->stages[3].mode;
1390        unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1391        unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1392        unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1393
1394        if (o_sha && (!a_sha || !b_sha)) {
1395                /* Case A: Deleted in one */
1396                if ((!a_sha && !b_sha) ||
1397                    (sha_eq(a_sha, o_sha) && !b_sha) ||
1398                    (!a_sha && sha_eq(b_sha, o_sha))) {
1399                        /* Deleted in both or deleted in one and
1400                         * unchanged in the other */
1401                        if (a_sha)
1402                                output(2, "Removed %s", path);
1403                        /* do not touch working file if it did not exist */
1404                        remove_file(1, path, !a_sha);
1405                } else {
1406                        /* Deleted in one and changed in the other */
1407                        clean_merge = 0;
1408                        if (!a_sha) {
1409                                output(1, "CONFLICT (delete/modify): %s deleted in %s "
1410                                       "and modified in %s. Version %s of %s left in tree.",
1411                                       path, branch1,
1412                                       branch2, branch2, path);
1413                                update_file(0, b_sha, b_mode, path);
1414                        } else {
1415                                output(1, "CONFLICT (delete/modify): %s deleted in %s "
1416                                       "and modified in %s. Version %s of %s left in tree.",
1417                                       path, branch2,
1418                                       branch1, branch1, path);
1419                                update_file(0, a_sha, a_mode, path);
1420                        }
1421                }
1422
1423        } else if ((!o_sha && a_sha && !b_sha) ||
1424                   (!o_sha && !a_sha && b_sha)) {
1425                /* Case B: Added in one. */
1426                const char *add_branch;
1427                const char *other_branch;
1428                unsigned mode;
1429                const unsigned char *sha;
1430                const char *conf;
1431
1432                if (a_sha) {
1433                        add_branch = branch1;
1434                        other_branch = branch2;
1435                        mode = a_mode;
1436                        sha = a_sha;
1437                        conf = "file/directory";
1438                } else {
1439                        add_branch = branch2;
1440                        other_branch = branch1;
1441                        mode = b_mode;
1442                        sha = b_sha;
1443                        conf = "directory/file";
1444                }
1445                if (path_list_has_path(&current_directory_set, path)) {
1446                        const char *new_path = unique_path(path, add_branch);
1447                        clean_merge = 0;
1448                        output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
1449                               "Added %s as %s",
1450                               conf, path, other_branch, path, new_path);
1451                        remove_file(0, path, 0);
1452                        update_file(0, sha, mode, new_path);
1453                } else {
1454                        output(2, "Added %s", path);
1455                        update_file(1, sha, mode, path);
1456                }
1457        } else if (a_sha && b_sha) {
1458                /* Case C: Added in both (check for same permissions) and */
1459                /* case D: Modified in both, but differently. */
1460                const char *reason = "content";
1461                struct merge_file_info mfi;
1462                struct diff_filespec o, a, b;
1463
1464                if (!o_sha) {
1465                        reason = "add/add";
1466                        o_sha = (unsigned char *)null_sha1;
1467                }
1468                output(2, "Auto-merged %s", path);
1469                o.path = a.path = b.path = (char *)path;
1470                hashcpy(o.sha1, o_sha);
1471                o.mode = o_mode;
1472                hashcpy(a.sha1, a_sha);
1473                a.mode = a_mode;
1474                hashcpy(b.sha1, b_sha);
1475                b.mode = b_mode;
1476
1477                mfi = merge_file(&o, &a, &b,
1478                                 branch1, branch2);
1479
1480                if (mfi.clean)
1481                        update_file(1, mfi.sha, mfi.mode, path);
1482                else {
1483                        clean_merge = 0;
1484                        output(1, "CONFLICT (%s): Merge conflict in %s",
1485                                        reason, path);
1486
1487                        if (index_only)
1488                                update_file(0, mfi.sha, mfi.mode, path);
1489                        else
1490                                update_file_flags(mfi.sha, mfi.mode, path,
1491                                              0 /* update_cache */, 1 /* update_working_directory */);
1492                }
1493        } else if (!o_sha && !a_sha && !b_sha) {
1494                /*
1495                 * this entry was deleted altogether. a_mode == 0 means
1496                 * we had that path and want to actively remove it.
1497                 */
1498                remove_file(1, path, !a_mode);
1499        } else
1500                die("Fatal merge failure, shouldn't happen.");
1501
1502        return clean_merge;
1503}
1504
1505static int merge_trees(struct tree *head,
1506                       struct tree *merge,
1507                       struct tree *common,
1508                       const char *branch1,
1509                       const char *branch2,
1510                       struct tree **result)
1511{
1512        int code, clean;
1513
1514        if (subtree_merge) {
1515                merge = shift_tree_object(head, merge);
1516                common = shift_tree_object(head, common);
1517        }
1518
1519        if (sha_eq(common->object.sha1, merge->object.sha1)) {
1520                output(0, "Already uptodate!");
1521                *result = head;
1522                return 1;
1523        }
1524
1525        code = git_merge_trees(index_only, common, head, merge);
1526
1527        if (code != 0)
1528                die("merging of trees %s and %s failed",
1529                    sha1_to_hex(head->object.sha1),
1530                    sha1_to_hex(merge->object.sha1));
1531
1532        if (unmerged_index()) {
1533                struct path_list *entries, *re_head, *re_merge;
1534                int i;
1535                path_list_clear(&current_file_set, 1);
1536                path_list_clear(&current_directory_set, 1);
1537                get_files_dirs(head);
1538                get_files_dirs(merge);
1539
1540                entries = get_unmerged();
1541                re_head  = get_renames(head, common, head, merge, entries);
1542                re_merge = get_renames(merge, common, head, merge, entries);
1543                clean = process_renames(re_head, re_merge,
1544                                branch1, branch2);
1545                for (i = 0; i < entries->nr; i++) {
1546                        const char *path = entries->items[i].path;
1547                        struct stage_data *e = entries->items[i].util;
1548                        if (!e->processed
1549                                && !process_entry(path, e, branch1, branch2))
1550                                clean = 0;
1551                }
1552
1553                path_list_clear(re_merge, 0);
1554                path_list_clear(re_head, 0);
1555                path_list_clear(entries, 1);
1556
1557        }
1558        else
1559                clean = 1;
1560
1561        if (index_only)
1562                *result = git_write_tree();
1563
1564        return clean;
1565}
1566
1567static struct commit_list *reverse_commit_list(struct commit_list *list)
1568{
1569        struct commit_list *next = NULL, *current, *backup;
1570        for (current = list; current; current = backup) {
1571                backup = current->next;
1572                current->next = next;
1573                next = current;
1574        }
1575        return next;
1576}
1577
1578/*
1579 * Merge the commits h1 and h2, return the resulting virtual
1580 * commit object and a flag indicating the cleanness of the merge.
1581 */
1582static int merge(struct commit *h1,
1583                 struct commit *h2,
1584                 const char *branch1,
1585                 const char *branch2,
1586                 struct commit_list *ca,
1587                 struct commit **result)
1588{
1589        struct commit_list *iter;
1590        struct commit *merged_common_ancestors;
1591        struct tree *mrtree = mrtree;
1592        int clean;
1593
1594        if (show(4)) {
1595                output(4, "Merging:");
1596                output_commit_title(h1);
1597                output_commit_title(h2);
1598        }
1599
1600        if (!ca) {
1601                ca = get_merge_bases(h1, h2, 1);
1602                ca = reverse_commit_list(ca);
1603        }
1604
1605        if (show(5)) {
1606                output(5, "found %u common ancestor(s):", commit_list_count(ca));
1607                for (iter = ca; iter; iter = iter->next)
1608                        output_commit_title(iter->item);
1609        }
1610
1611        merged_common_ancestors = pop_commit(&ca);
1612        if (merged_common_ancestors == NULL) {
1613                /* if there is no common ancestor, make an empty tree */
1614                struct tree *tree = xcalloc(1, sizeof(struct tree));
1615
1616                tree->object.parsed = 1;
1617                tree->object.type = OBJ_TREE;
1618                pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1619                merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1620        }
1621
1622        for (iter = ca; iter; iter = iter->next) {
1623                call_depth++;
1624                /*
1625                 * When the merge fails, the result contains files
1626                 * with conflict markers. The cleanness flag is
1627                 * ignored, it was never actually used, as result of
1628                 * merge_trees has always overwritten it: the committed
1629                 * "conflicts" were already resolved.
1630                 */
1631                discard_cache();
1632                merge(merged_common_ancestors, iter->item,
1633                      "Temporary merge branch 1",
1634                      "Temporary merge branch 2",
1635                      NULL,
1636                      &merged_common_ancestors);
1637                call_depth--;
1638
1639                if (!merged_common_ancestors)
1640                        die("merge returned no commit");
1641        }
1642
1643        discard_cache();
1644        if (!call_depth) {
1645                read_cache();
1646                index_only = 0;
1647        } else
1648                index_only = 1;
1649
1650        clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1651                            branch1, branch2, &mrtree);
1652
1653        if (index_only) {
1654                *result = make_virtual_commit(mrtree, "merged tree");
1655                commit_list_insert(h1, &(*result)->parents);
1656                commit_list_insert(h2, &(*result)->parents->next);
1657        }
1658        flush_output();
1659        return clean;
1660}
1661
1662static const char *better_branch_name(const char *branch)
1663{
1664        static char githead_env[8 + 40 + 1];
1665        char *name;
1666
1667        if (strlen(branch) != 40)
1668                return branch;
1669        sprintf(githead_env, "GITHEAD_%s", branch);
1670        name = getenv(githead_env);
1671        return name ? name : branch;
1672}
1673
1674static struct commit *get_ref(const char *ref)
1675{
1676        unsigned char sha1[20];
1677        struct object *object;
1678
1679        if (get_sha1(ref, sha1))
1680                die("Could not resolve ref '%s'", ref);
1681        object = deref_tag(parse_object(sha1), ref, strlen(ref));
1682        if (object->type == OBJ_TREE)
1683                return make_virtual_commit((struct tree*)object,
1684                        better_branch_name(ref));
1685        if (object->type != OBJ_COMMIT)
1686                return NULL;
1687        if (parse_commit((struct commit *)object))
1688                die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1689        return (struct commit *)object;
1690}
1691
1692static int merge_config(const char *var, const char *value)
1693{
1694        if (!strcasecmp(var, "merge.verbosity")) {
1695                verbosity = git_config_int(var, value);
1696                return 0;
1697        }
1698        if (!strcasecmp(var, "diff.renamelimit")) {
1699                rename_limit = git_config_int(var, value);
1700                return 0;
1701        }
1702        return git_default_config(var, value);
1703}
1704
1705int main(int argc, char *argv[])
1706{
1707        static const char *bases[20];
1708        static unsigned bases_count = 0;
1709        int i, clean;
1710        const char *branch1, *branch2;
1711        struct commit *result, *h1, *h2;
1712        struct commit_list *ca = NULL;
1713        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1714        int index_fd;
1715
1716        if (argv[0]) {
1717                int namelen = strlen(argv[0]);
1718                if (8 < namelen &&
1719                    !strcmp(argv[0] + namelen - 8, "-subtree"))
1720                        subtree_merge = 1;
1721        }
1722
1723        git_config(merge_config);
1724        if (getenv("GIT_MERGE_VERBOSITY"))
1725                verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1726
1727        if (argc < 4)
1728                die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1729
1730        for (i = 1; i < argc; ++i) {
1731                if (!strcmp(argv[i], "--"))
1732                        break;
1733                if (bases_count < sizeof(bases)/sizeof(*bases))
1734                        bases[bases_count++] = argv[i];
1735        }
1736        if (argc - i != 3) /* "--" "<head>" "<remote>" */
1737                die("Not handling anything other than two heads merge.");
1738        if (verbosity >= 5)
1739                buffer_output = 0;
1740
1741        branch1 = argv[++i];
1742        branch2 = argv[++i];
1743
1744        h1 = get_ref(branch1);
1745        h2 = get_ref(branch2);
1746
1747        branch1 = better_branch_name(branch1);
1748        branch2 = better_branch_name(branch2);
1749
1750        if (show(3))
1751                printf("Merging %s with %s\n", branch1, branch2);
1752
1753        index_fd = hold_locked_index(lock, 1);
1754
1755        for (i = 0; i < bases_count; i++) {
1756                struct commit *ancestor = get_ref(bases[i]);
1757                ca = commit_list_insert(ancestor, &ca);
1758        }
1759        clean = merge(h1, h2, branch1, branch2, ca, &result);
1760
1761        if (active_cache_changed &&
1762            (write_cache(index_fd, active_cache, active_nr) ||
1763             close(index_fd) || commit_locked_index(lock)))
1764                        die ("unable to write %s", get_index_file());
1765
1766        return clean ? 0: 1;
1767}