merge-recursive.con commit merge-recursive: do not use on-file index when not needed. (8b944b5)
   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
  19/*
  20 * A virtual commit has
  21 * - (const char *)commit->util set to the name, and
  22 * - *(int *)commit->object.sha1 set to the virtual id.
  23 */
  24
  25static unsigned commit_list_count(const struct commit_list *l)
  26{
  27        unsigned c = 0;
  28        for (; l; l = l->next )
  29                c++;
  30        return c;
  31}
  32
  33static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  34{
  35        struct commit *commit = xcalloc(1, sizeof(struct commit));
  36        static unsigned virtual_id = 1;
  37        commit->tree = tree;
  38        commit->util = (void*)comment;
  39        *(int*)commit->object.sha1 = virtual_id++;
  40        /* avoid warnings */
  41        commit->object.parsed = 1;
  42        return commit;
  43}
  44
  45/*
  46 * Since we use get_tree_entry(), which does not put the read object into
  47 * the object pool, we cannot rely on a == b.
  48 */
  49static int sha_eq(const unsigned char *a, const unsigned char *b)
  50{
  51        if (!a && !b)
  52                return 2;
  53        return a && b && hashcmp(a, b) == 0;
  54}
  55
  56/*
  57 * Since we want to write the index eventually, we cannot reuse the index
  58 * for these (temporary) data.
  59 */
  60struct stage_data
  61{
  62        struct
  63        {
  64                unsigned mode;
  65                unsigned char sha[20];
  66        } stages[4];
  67        unsigned processed:1;
  68};
  69
  70static struct path_list current_file_set = {NULL, 0, 0, 1};
  71static struct path_list current_directory_set = {NULL, 0, 0, 1};
  72
  73static int output_indent = 0;
  74
  75static void output(const char *fmt, ...)
  76{
  77        va_list args;
  78        int i;
  79        for (i = output_indent; i--;)
  80                fputs("  ", stdout);
  81        va_start(args, fmt);
  82        vfprintf(stdout, fmt, args);
  83        va_end(args);
  84        fputc('\n', stdout);
  85}
  86
  87static void output_commit_title(struct commit *commit)
  88{
  89        int i;
  90        for (i = output_indent; i--;)
  91                fputs("  ", stdout);
  92        if (commit->util)
  93                printf("virtual %s\n", (char *)commit->util);
  94        else {
  95                printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
  96                if (parse_commit(commit) != 0)
  97                        printf("(bad commit)\n");
  98                else {
  99                        const char *s;
 100                        int len;
 101                        for (s = commit->buffer; *s; s++)
 102                                if (*s == '\n' && s[1] == '\n') {
 103                                        s += 2;
 104                                        break;
 105                                }
 106                        for (len = 0; s[len] && '\n' != s[len]; len++)
 107                                ; /* do nothing */
 108                        printf("%.*s\n", len, s);
 109                }
 110        }
 111}
 112
 113static struct cache_entry *make_cache_entry(unsigned int mode,
 114                const unsigned char *sha1, const char *path, int stage, int refresh)
 115{
 116        int size, len;
 117        struct cache_entry *ce;
 118
 119        if (!verify_path(path))
 120                return NULL;
 121
 122        len = strlen(path);
 123        size = cache_entry_size(len);
 124        ce = xcalloc(1, size);
 125
 126        hashcpy(ce->sha1, sha1);
 127        memcpy(ce->name, path, len);
 128        ce->ce_flags = create_ce_flags(len, stage);
 129        ce->ce_mode = create_ce_mode(mode);
 130
 131        if (refresh)
 132                return refresh_cache_entry(ce, 0);
 133
 134        return ce;
 135}
 136
 137static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 138                const char *path, int stage, int refresh, int options)
 139{
 140        struct cache_entry *ce;
 141        ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 142        if (!ce)
 143                return error("cache_addinfo failed: %s", strerror(cache_errno));
 144        return add_cache_entry(ce, options);
 145}
 146
 147/*
 148 * This is a global variable which is used in a number of places but
 149 * only written to in the 'merge' function.
 150 *
 151 * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
 152 *                       don't update the working directory.
 153 *               0    => Leave unmerged entries in the cache and update
 154 *                       the working directory.
 155 */
 156static int index_only = 0;
 157
 158static int git_merge_trees(int index_only,
 159                           struct tree *common,
 160                           struct tree *head,
 161                           struct tree *merge)
 162{
 163        int rc;
 164        struct object_list *trees = NULL;
 165        struct unpack_trees_options opts;
 166
 167        memset(&opts, 0, sizeof(opts));
 168        if (index_only)
 169                opts.index_only = 1;
 170        else
 171                opts.update = 1;
 172        opts.merge = 1;
 173        opts.head_idx = 2;
 174        opts.fn = threeway_merge;
 175
 176        object_list_append(&common->object, &trees);
 177        object_list_append(&head->object, &trees);
 178        object_list_append(&merge->object, &trees);
 179
 180        rc = unpack_trees(trees, &opts);
 181        cache_tree_free(&active_cache_tree);
 182        return rc;
 183}
 184
 185static int unmerged_index(void)
 186{
 187        int i;
 188        for (i = 0; i < active_nr; i++) {
 189                struct cache_entry *ce = active_cache[i];
 190                if (ce_stage(ce))
 191                        return 1;
 192        }
 193        return 0;
 194}
 195
 196static struct tree *git_write_tree(void)
 197{
 198        struct tree *result = NULL;
 199
 200        if (unmerged_index())
 201                return NULL;
 202
 203        if (!active_cache_tree)
 204                active_cache_tree = cache_tree();
 205
 206        if (!cache_tree_fully_valid(active_cache_tree) &&
 207            cache_tree_update(active_cache_tree,
 208                              active_cache, active_nr, 0, 0) < 0)
 209                die("error building trees");
 210
 211        result = lookup_tree(active_cache_tree->sha1);
 212
 213        return result;
 214}
 215
 216static int save_files_dirs(const unsigned char *sha1,
 217                const char *base, int baselen, const char *path,
 218                unsigned int mode, int stage)
 219{
 220        int len = strlen(path);
 221        char *newpath = xmalloc(baselen + len + 1);
 222        memcpy(newpath, base, baselen);
 223        memcpy(newpath + baselen, path, len);
 224        newpath[baselen + len] = '\0';
 225
 226        if (S_ISDIR(mode))
 227                path_list_insert(newpath, &current_directory_set);
 228        else
 229                path_list_insert(newpath, &current_file_set);
 230        free(newpath);
 231
 232        return READ_TREE_RECURSIVE;
 233}
 234
 235static int get_files_dirs(struct tree *tree)
 236{
 237        int n;
 238        if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
 239                return 0;
 240        n = current_file_set.nr + current_directory_set.nr;
 241        return n;
 242}
 243
 244/*
 245 * Returns a index_entry instance which doesn't have to correspond to
 246 * a real cache entry in Git's index.
 247 */
 248static struct stage_data *insert_stage_data(const char *path,
 249                struct tree *o, struct tree *a, struct tree *b,
 250                struct path_list *entries)
 251{
 252        struct path_list_item *item;
 253        struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 254        get_tree_entry(o->object.sha1, path,
 255                        e->stages[1].sha, &e->stages[1].mode);
 256        get_tree_entry(a->object.sha1, path,
 257                        e->stages[2].sha, &e->stages[2].mode);
 258        get_tree_entry(b->object.sha1, path,
 259                        e->stages[3].sha, &e->stages[3].mode);
 260        item = path_list_insert(path, entries);
 261        item->util = e;
 262        return e;
 263}
 264
 265/*
 266 * Create a dictionary mapping file names to stage_data objects. The
 267 * dictionary contains one entry for every path with a non-zero stage entry.
 268 */
 269static struct path_list *get_unmerged(void)
 270{
 271        struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
 272        int i;
 273
 274        unmerged->strdup_paths = 1;
 275
 276        for (i = 0; i < active_nr; i++) {
 277                struct path_list_item *item;
 278                struct stage_data *e;
 279                struct cache_entry *ce = active_cache[i];
 280                if (!ce_stage(ce))
 281                        continue;
 282
 283                item = path_list_lookup(ce->name, unmerged);
 284                if (!item) {
 285                        item = path_list_insert(ce->name, unmerged);
 286                        item->util = xcalloc(1, sizeof(struct stage_data));
 287                }
 288                e = item->util;
 289                e->stages[ce_stage(ce)].mode = ntohl(ce->ce_mode);
 290                hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 291        }
 292
 293        return unmerged;
 294}
 295
 296struct rename
 297{
 298        struct diff_filepair *pair;
 299        struct stage_data *src_entry;
 300        struct stage_data *dst_entry;
 301        unsigned processed:1;
 302};
 303
 304/*
 305 * Get information of all renames which occured between 'o_tree' and
 306 * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 307 * 'b_tree') to be able to associate the correct cache entries with
 308 * the rename information. 'tree' is always equal to either a_tree or b_tree.
 309 */
 310static struct path_list *get_renames(struct tree *tree,
 311                                        struct tree *o_tree,
 312                                        struct tree *a_tree,
 313                                        struct tree *b_tree,
 314                                        struct path_list *entries)
 315{
 316        int i;
 317        struct path_list *renames;
 318        struct diff_options opts;
 319
 320        renames = xcalloc(1, sizeof(struct path_list));
 321        diff_setup(&opts);
 322        opts.recursive = 1;
 323        opts.detect_rename = DIFF_DETECT_RENAME;
 324        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 325        if (diff_setup_done(&opts) < 0)
 326                die("diff setup failed");
 327        diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 328        diffcore_std(&opts);
 329        for (i = 0; i < diff_queued_diff.nr; ++i) {
 330                struct path_list_item *item;
 331                struct rename *re;
 332                struct diff_filepair *pair = diff_queued_diff.queue[i];
 333                if (pair->status != 'R') {
 334                        diff_free_filepair(pair);
 335                        continue;
 336                }
 337                re = xmalloc(sizeof(*re));
 338                re->processed = 0;
 339                re->pair = pair;
 340                item = path_list_lookup(re->pair->one->path, entries);
 341                if (!item)
 342                        re->src_entry = insert_stage_data(re->pair->one->path,
 343                                        o_tree, a_tree, b_tree, entries);
 344                else
 345                        re->src_entry = item->util;
 346
 347                item = path_list_lookup(re->pair->two->path, entries);
 348                if (!item)
 349                        re->dst_entry = insert_stage_data(re->pair->two->path,
 350                                        o_tree, a_tree, b_tree, entries);
 351                else
 352                        re->dst_entry = item->util;
 353                item = path_list_insert(pair->one->path, renames);
 354                item->util = re;
 355        }
 356        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 357        diff_queued_diff.nr = 0;
 358        diff_flush(&opts);
 359        return renames;
 360}
 361
 362static int update_stages(const char *path, struct diff_filespec *o,
 363                         struct diff_filespec *a, struct diff_filespec *b,
 364                         int clear)
 365{
 366        int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 367        if (clear)
 368                if (remove_file_from_cache(path))
 369                        return -1;
 370        if (o)
 371                if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 372                        return -1;
 373        if (a)
 374                if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 375                        return -1;
 376        if (b)
 377                if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 378                        return -1;
 379        return 0;
 380}
 381
 382static int remove_path(const char *name)
 383{
 384        int ret, len;
 385        char *slash, *dirs;
 386
 387        ret = unlink(name);
 388        if (ret)
 389                return ret;
 390        len = strlen(name);
 391        dirs = xmalloc(len+1);
 392        memcpy(dirs, name, len);
 393        dirs[len] = '\0';
 394        while ((slash = strrchr(name, '/'))) {
 395                *slash = '\0';
 396                len = slash - name;
 397                if (rmdir(name) != 0)
 398                        break;
 399        }
 400        free(dirs);
 401        return ret;
 402}
 403
 404static int remove_file(int clean, const char *path, int no_wd)
 405{
 406        int update_cache = index_only || clean;
 407        int update_working_directory = !index_only && !no_wd;
 408
 409        if (update_cache) {
 410                if (remove_file_from_cache(path))
 411                        return -1;
 412        }
 413        if (update_working_directory) {
 414                unlink(path);
 415                if (errno != ENOENT || errno != EISDIR)
 416                        return -1;
 417                remove_path(path);
 418        }
 419        return 0;
 420}
 421
 422static char *unique_path(const char *path, const char *branch)
 423{
 424        char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 425        int suffix = 0;
 426        struct stat st;
 427        char *p = newpath + strlen(path);
 428        strcpy(newpath, path);
 429        *(p++) = '~';
 430        strcpy(p, branch);
 431        for (; *p; ++p)
 432                if ('/' == *p)
 433                        *p = '_';
 434        while (path_list_has_path(&current_file_set, newpath) ||
 435               path_list_has_path(&current_directory_set, newpath) ||
 436               lstat(newpath, &st) == 0)
 437                sprintf(p, "_%d", suffix++);
 438
 439        path_list_insert(newpath, &current_file_set);
 440        return newpath;
 441}
 442
 443static int mkdir_p(const char *path, unsigned long mode)
 444{
 445        /* path points to cache entries, so xstrdup before messing with it */
 446        char *buf = xstrdup(path);
 447        int result = safe_create_leading_directories(buf);
 448        free(buf);
 449        return result;
 450}
 451
 452static void flush_buffer(int fd, const char *buf, unsigned long size)
 453{
 454        while (size > 0) {
 455                long ret = write_in_full(fd, buf, size);
 456                if (ret < 0) {
 457                        /* Ignore epipe */
 458                        if (errno == EPIPE)
 459                                break;
 460                        die("merge-recursive: %s", strerror(errno));
 461                } else if (!ret) {
 462                        die("merge-recursive: disk full?");
 463                }
 464                size -= ret;
 465                buf += ret;
 466        }
 467}
 468
 469static void update_file_flags(const unsigned char *sha,
 470                              unsigned mode,
 471                              const char *path,
 472                              int update_cache,
 473                              int update_wd)
 474{
 475        if (index_only)
 476                update_wd = 0;
 477
 478        if (update_wd) {
 479                char type[20];
 480                void *buf;
 481                unsigned long size;
 482
 483                buf = read_sha1_file(sha, type, &size);
 484                if (!buf)
 485                        die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 486                if (strcmp(type, blob_type) != 0)
 487                        die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 488
 489                if (S_ISREG(mode)) {
 490                        int fd;
 491                        if (mkdir_p(path, 0777))
 492                                die("failed to create path %s: %s", path, strerror(errno));
 493                        unlink(path);
 494                        if (mode & 0100)
 495                                mode = 0777;
 496                        else
 497                                mode = 0666;
 498                        fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 499                        if (fd < 0)
 500                                die("failed to open %s: %s", path, strerror(errno));
 501                        flush_buffer(fd, buf, size);
 502                        close(fd);
 503                } else if (S_ISLNK(mode)) {
 504                        char *lnk = xmalloc(size + 1);
 505                        memcpy(lnk, buf, size);
 506                        lnk[size] = '\0';
 507                        mkdir_p(path, 0777);
 508                        unlink(lnk);
 509                        symlink(lnk, path);
 510                } else
 511                        die("do not know what to do with %06o %s '%s'",
 512                            mode, sha1_to_hex(sha), path);
 513        }
 514        if (update_cache)
 515                add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 516}
 517
 518static void update_file(int clean,
 519                        const unsigned char *sha,
 520                        unsigned mode,
 521                        const char *path)
 522{
 523        update_file_flags(sha, mode, path, index_only || clean, !index_only);
 524}
 525
 526/* Low level file merging, update and removal */
 527
 528struct merge_file_info
 529{
 530        unsigned char sha[20];
 531        unsigned mode;
 532        unsigned clean:1,
 533                 merge:1;
 534};
 535
 536static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 537{
 538        unsigned long size;
 539        char type[20];
 540
 541        if (!hashcmp(sha1, null_sha1)) {
 542                mm->ptr = xstrdup("");
 543                mm->size = 0;
 544                return;
 545        }
 546
 547        mm->ptr = read_sha1_file(sha1, type, &size);
 548        if (!mm->ptr || strcmp(type, blob_type))
 549                die("unable to read blob object %s", sha1_to_hex(sha1));
 550        mm->size = size;
 551}
 552
 553static struct merge_file_info merge_file(struct diff_filespec *o,
 554                struct diff_filespec *a, struct diff_filespec *b,
 555                const char *branch1, const char *branch2)
 556{
 557        struct merge_file_info result;
 558        result.merge = 0;
 559        result.clean = 1;
 560
 561        if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 562                result.clean = 0;
 563                if (S_ISREG(a->mode)) {
 564                        result.mode = a->mode;
 565                        hashcpy(result.sha, a->sha1);
 566                } else {
 567                        result.mode = b->mode;
 568                        hashcpy(result.sha, b->sha1);
 569                }
 570        } else {
 571                if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
 572                        result.merge = 1;
 573
 574                result.mode = a->mode == o->mode ? b->mode: a->mode;
 575
 576                if (sha_eq(a->sha1, o->sha1))
 577                        hashcpy(result.sha, b->sha1);
 578                else if (sha_eq(b->sha1, o->sha1))
 579                        hashcpy(result.sha, a->sha1);
 580                else if (S_ISREG(a->mode)) {
 581                        mmfile_t orig, src1, src2;
 582                        mmbuffer_t result_buf;
 583                        xpparam_t xpp;
 584                        char *name1, *name2;
 585                        int merge_status;
 586
 587                        name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 588                        name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 589
 590                        fill_mm(o->sha1, &orig);
 591                        fill_mm(a->sha1, &src1);
 592                        fill_mm(b->sha1, &src2);
 593
 594                        memset(&xpp, 0, sizeof(xpp));
 595                        merge_status = xdl_merge(&orig,
 596                                                 &src1, name1,
 597                                                 &src2, name2,
 598                                                 &xpp, XDL_MERGE_ZEALOUS,
 599                                                 &result_buf);
 600                        free(name1);
 601                        free(name2);
 602                        free(orig.ptr);
 603                        free(src1.ptr);
 604                        free(src2.ptr);
 605
 606                        if ((merge_status < 0) || !result_buf.ptr)
 607                                die("Failed to execute internal merge");
 608
 609                        if (write_sha1_file(result_buf.ptr, result_buf.size,
 610                                            blob_type, result.sha))
 611                                die("Unable to add %s to database",
 612                                    a->path);
 613
 614                        free(result_buf.ptr);
 615                        result.clean = (merge_status == 0);
 616                } else {
 617                        if (!(S_ISLNK(a->mode) || S_ISLNK(b->mode)))
 618                                die("cannot merge modes?");
 619
 620                        hashcpy(result.sha, a->sha1);
 621
 622                        if (!sha_eq(a->sha1, b->sha1))
 623                                result.clean = 0;
 624                }
 625        }
 626
 627        return result;
 628}
 629
 630static void conflict_rename_rename(struct rename *ren1,
 631                                   const char *branch1,
 632                                   struct rename *ren2,
 633                                   const char *branch2)
 634{
 635        char *del[2];
 636        int delp = 0;
 637        const char *ren1_dst = ren1->pair->two->path;
 638        const char *ren2_dst = ren2->pair->two->path;
 639        const char *dst_name1 = ren1_dst;
 640        const char *dst_name2 = ren2_dst;
 641        if (path_list_has_path(&current_directory_set, ren1_dst)) {
 642                dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
 643                output("%s is a directory in %s adding as %s instead",
 644                       ren1_dst, branch2, dst_name1);
 645                remove_file(0, ren1_dst, 0);
 646        }
 647        if (path_list_has_path(&current_directory_set, ren2_dst)) {
 648                dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
 649                output("%s is a directory in %s adding as %s instead",
 650                       ren2_dst, branch1, dst_name2);
 651                remove_file(0, ren2_dst, 0);
 652        }
 653        update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 654        update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 655        while (delp--)
 656                free(del[delp]);
 657}
 658
 659static void conflict_rename_dir(struct rename *ren1,
 660                                const char *branch1)
 661{
 662        char *new_path = unique_path(ren1->pair->two->path, branch1);
 663        output("Renaming %s to %s instead", ren1->pair->one->path, new_path);
 664        remove_file(0, ren1->pair->two->path, 0);
 665        update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 666        free(new_path);
 667}
 668
 669static void conflict_rename_rename_2(struct rename *ren1,
 670                                     const char *branch1,
 671                                     struct rename *ren2,
 672                                     const char *branch2)
 673{
 674        char *new_path1 = unique_path(ren1->pair->two->path, branch1);
 675        char *new_path2 = unique_path(ren2->pair->two->path, branch2);
 676        output("Renaming %s to %s and %s to %s instead",
 677               ren1->pair->one->path, new_path1,
 678               ren2->pair->one->path, new_path2);
 679        remove_file(0, ren1->pair->two->path, 0);
 680        update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 681        update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 682        free(new_path2);
 683        free(new_path1);
 684}
 685
 686static int process_renames(struct path_list *a_renames,
 687                           struct path_list *b_renames,
 688                           const char *a_branch,
 689                           const char *b_branch)
 690{
 691        int clean_merge = 1, i, j;
 692        struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 693        const struct rename *sre;
 694
 695        for (i = 0; i < a_renames->nr; i++) {
 696                sre = a_renames->items[i].util;
 697                path_list_insert(sre->pair->two->path, &a_by_dst)->util
 698                        = sre->dst_entry;
 699        }
 700        for (i = 0; i < b_renames->nr; i++) {
 701                sre = b_renames->items[i].util;
 702                path_list_insert(sre->pair->two->path, &b_by_dst)->util
 703                        = sre->dst_entry;
 704        }
 705
 706        for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 707                int compare;
 708                char *src;
 709                struct path_list *renames1, *renames2, *renames2Dst;
 710                struct rename *ren1 = NULL, *ren2 = NULL;
 711                const char *branch1, *branch2;
 712                const char *ren1_src, *ren1_dst;
 713
 714                if (i >= a_renames->nr) {
 715                        compare = 1;
 716                        ren2 = b_renames->items[j++].util;
 717                } else if (j >= b_renames->nr) {
 718                        compare = -1;
 719                        ren1 = a_renames->items[i++].util;
 720                } else {
 721                        compare = strcmp(a_renames->items[i].path,
 722                                        b_renames->items[j].path);
 723                        if (compare <= 0)
 724                                ren1 = a_renames->items[i++].util;
 725                        if (compare >= 0)
 726                                ren2 = b_renames->items[j++].util;
 727                }
 728
 729                /* TODO: refactor, so that 1/2 are not needed */
 730                if (ren1) {
 731                        renames1 = a_renames;
 732                        renames2 = b_renames;
 733                        renames2Dst = &b_by_dst;
 734                        branch1 = a_branch;
 735                        branch2 = b_branch;
 736                } else {
 737                        struct rename *tmp;
 738                        renames1 = b_renames;
 739                        renames2 = a_renames;
 740                        renames2Dst = &a_by_dst;
 741                        branch1 = b_branch;
 742                        branch2 = a_branch;
 743                        tmp = ren2;
 744                        ren2 = ren1;
 745                        ren1 = tmp;
 746                }
 747                src = ren1->pair->one->path;
 748
 749                ren1->dst_entry->processed = 1;
 750                ren1->src_entry->processed = 1;
 751
 752                if (ren1->processed)
 753                        continue;
 754                ren1->processed = 1;
 755
 756                ren1_src = ren1->pair->one->path;
 757                ren1_dst = ren1->pair->two->path;
 758
 759                if (ren2) {
 760                        const char *ren2_src = ren2->pair->one->path;
 761                        const char *ren2_dst = ren2->pair->two->path;
 762                        /* Renamed in 1 and renamed in 2 */
 763                        if (strcmp(ren1_src, ren2_src) != 0)
 764                                die("ren1.src != ren2.src");
 765                        ren2->dst_entry->processed = 1;
 766                        ren2->processed = 1;
 767                        if (strcmp(ren1_dst, ren2_dst) != 0) {
 768                                clean_merge = 0;
 769                                output("CONFLICT (rename/rename): "
 770                                       "Rename %s->%s in branch %s "
 771                                       "rename %s->%s in %s",
 772                                       src, ren1_dst, branch1,
 773                                       src, ren2_dst, branch2);
 774                                conflict_rename_rename(ren1, branch1, ren2, branch2);
 775                        } else {
 776                                struct merge_file_info mfi;
 777                                remove_file(1, ren1_src, 1);
 778                                mfi = merge_file(ren1->pair->one,
 779                                                 ren1->pair->two,
 780                                                 ren2->pair->two,
 781                                                 branch1,
 782                                                 branch2);
 783                                if (mfi.merge || !mfi.clean)
 784                                        output("Renaming %s->%s", src, ren1_dst);
 785
 786                                if (mfi.merge)
 787                                        output("Auto-merging %s", ren1_dst);
 788
 789                                if (!mfi.clean) {
 790                                        output("CONFLICT (content): merge conflict in %s",
 791                                               ren1_dst);
 792                                        clean_merge = 0;
 793
 794                                        if (!index_only)
 795                                                update_stages(ren1_dst,
 796                                                              ren1->pair->one,
 797                                                              ren1->pair->two,
 798                                                              ren2->pair->two,
 799                                                              1 /* clear */);
 800                                }
 801                                update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 802                        }
 803                } else {
 804                        /* Renamed in 1, maybe changed in 2 */
 805                        struct path_list_item *item;
 806                        /* we only use sha1 and mode of these */
 807                        struct diff_filespec src_other, dst_other;
 808                        int try_merge, stage = a_renames == renames1 ? 3: 2;
 809
 810                        remove_file(1, ren1_src, index_only);
 811
 812                        hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 813                        src_other.mode = ren1->src_entry->stages[stage].mode;
 814                        hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 815                        dst_other.mode = ren1->dst_entry->stages[stage].mode;
 816
 817                        try_merge = 0;
 818
 819                        if (path_list_has_path(&current_directory_set, ren1_dst)) {
 820                                clean_merge = 0;
 821                                output("CONFLICT (rename/directory): Rename %s->%s in %s "
 822                                       " directory %s added in %s",
 823                                       ren1_src, ren1_dst, branch1,
 824                                       ren1_dst, branch2);
 825                                conflict_rename_dir(ren1, branch1);
 826                        } else if (sha_eq(src_other.sha1, null_sha1)) {
 827                                clean_merge = 0;
 828                                output("CONFLICT (rename/delete): Rename %s->%s in %s "
 829                                       "and deleted in %s",
 830                                       ren1_src, ren1_dst, branch1,
 831                                       branch2);
 832                                update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 833                        } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 834                                const char *new_path;
 835                                clean_merge = 0;
 836                                try_merge = 1;
 837                                output("CONFLICT (rename/add): Rename %s->%s in %s. "
 838                                       "%s added in %s",
 839                                       ren1_src, ren1_dst, branch1,
 840                                       ren1_dst, branch2);
 841                                new_path = unique_path(ren1_dst, branch2);
 842                                output("Adding as %s instead", new_path);
 843                                update_file(0, dst_other.sha1, dst_other.mode, new_path);
 844                        } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
 845                                ren2 = item->util;
 846                                clean_merge = 0;
 847                                ren2->processed = 1;
 848                                output("CONFLICT (rename/rename): Rename %s->%s in %s. "
 849                                       "Rename %s->%s in %s",
 850                                       ren1_src, ren1_dst, branch1,
 851                                       ren2->pair->one->path, ren2->pair->two->path, branch2);
 852                                conflict_rename_rename_2(ren1, branch1, ren2, branch2);
 853                        } else
 854                                try_merge = 1;
 855
 856                        if (try_merge) {
 857                                struct diff_filespec *o, *a, *b;
 858                                struct merge_file_info mfi;
 859                                src_other.path = (char *)ren1_src;
 860
 861                                o = ren1->pair->one;
 862                                if (a_renames == renames1) {
 863                                        a = ren1->pair->two;
 864                                        b = &src_other;
 865                                } else {
 866                                        b = ren1->pair->two;
 867                                        a = &src_other;
 868                                }
 869                                mfi = merge_file(o, a, b,
 870                                                a_branch, b_branch);
 871
 872                                if (mfi.merge || !mfi.clean)
 873                                        output("Renaming %s => %s", ren1_src, ren1_dst);
 874                                if (mfi.merge)
 875                                        output("Auto-merging %s", ren1_dst);
 876                                if (!mfi.clean) {
 877                                        output("CONFLICT (rename/modify): Merge conflict in %s",
 878                                               ren1_dst);
 879                                        clean_merge = 0;
 880
 881                                        if (!index_only)
 882                                                update_stages(ren1_dst,
 883                                                                o, a, b, 1);
 884                                }
 885                                update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 886                        }
 887                }
 888        }
 889        path_list_clear(&a_by_dst, 0);
 890        path_list_clear(&b_by_dst, 0);
 891
 892        return clean_merge;
 893}
 894
 895static unsigned char *has_sha(const unsigned char *sha)
 896{
 897        return is_null_sha1(sha) ? NULL: (unsigned char *)sha;
 898}
 899
 900/* Per entry merge function */
 901static int process_entry(const char *path, struct stage_data *entry,
 902                         const char *branch1,
 903                         const char *branch2)
 904{
 905        /*
 906        printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
 907        print_index_entry("\tpath: ", entry);
 908        */
 909        int clean_merge = 1;
 910        unsigned char *o_sha = has_sha(entry->stages[1].sha);
 911        unsigned char *a_sha = has_sha(entry->stages[2].sha);
 912        unsigned char *b_sha = has_sha(entry->stages[3].sha);
 913        unsigned o_mode = entry->stages[1].mode;
 914        unsigned a_mode = entry->stages[2].mode;
 915        unsigned b_mode = entry->stages[3].mode;
 916
 917        if (o_sha && (!a_sha || !b_sha)) {
 918                /* Case A: Deleted in one */
 919                if ((!a_sha && !b_sha) ||
 920                    (sha_eq(a_sha, o_sha) && !b_sha) ||
 921                    (!a_sha && sha_eq(b_sha, o_sha))) {
 922                        /* Deleted in both or deleted in one and
 923                         * unchanged in the other */
 924                        if (a_sha)
 925                                output("Removing %s", path);
 926                        /* do not touch working file if it did not exist */
 927                        remove_file(1, path, !a_sha);
 928                } else {
 929                        /* Deleted in one and changed in the other */
 930                        clean_merge = 0;
 931                        if (!a_sha) {
 932                                output("CONFLICT (delete/modify): %s deleted in %s "
 933                                       "and modified in %s. Version %s of %s left in tree.",
 934                                       path, branch1,
 935                                       branch2, branch2, path);
 936                                update_file(0, b_sha, b_mode, path);
 937                        } else {
 938                                output("CONFLICT (delete/modify): %s deleted in %s "
 939                                       "and modified in %s. Version %s of %s left in tree.",
 940                                       path, branch2,
 941                                       branch1, branch1, path);
 942                                update_file(0, a_sha, a_mode, path);
 943                        }
 944                }
 945
 946        } else if ((!o_sha && a_sha && !b_sha) ||
 947                   (!o_sha && !a_sha && b_sha)) {
 948                /* Case B: Added in one. */
 949                const char *add_branch;
 950                const char *other_branch;
 951                unsigned mode;
 952                const unsigned char *sha;
 953                const char *conf;
 954
 955                if (a_sha) {
 956                        add_branch = branch1;
 957                        other_branch = branch2;
 958                        mode = a_mode;
 959                        sha = a_sha;
 960                        conf = "file/directory";
 961                } else {
 962                        add_branch = branch2;
 963                        other_branch = branch1;
 964                        mode = b_mode;
 965                        sha = b_sha;
 966                        conf = "directory/file";
 967                }
 968                if (path_list_has_path(&current_directory_set, path)) {
 969                        const char *new_path = unique_path(path, add_branch);
 970                        clean_merge = 0;
 971                        output("CONFLICT (%s): There is a directory with name %s in %s. "
 972                               "Adding %s as %s",
 973                               conf, path, other_branch, path, new_path);
 974                        remove_file(0, path, 0);
 975                        update_file(0, sha, mode, new_path);
 976                } else {
 977                        output("Adding %s", path);
 978                        update_file(1, sha, mode, path);
 979                }
 980        } else if (a_sha && b_sha) {
 981                /* Case C: Added in both (check for same permissions) and */
 982                /* case D: Modified in both, but differently. */
 983                const char *reason = "content";
 984                struct merge_file_info mfi;
 985                struct diff_filespec o, a, b;
 986
 987                if (!o_sha) {
 988                        reason = "add/add";
 989                        o_sha = (unsigned char *)null_sha1;
 990                }
 991                output("Auto-merging %s", path);
 992                o.path = a.path = b.path = (char *)path;
 993                hashcpy(o.sha1, o_sha);
 994                o.mode = o_mode;
 995                hashcpy(a.sha1, a_sha);
 996                a.mode = a_mode;
 997                hashcpy(b.sha1, b_sha);
 998                b.mode = b_mode;
 999
1000                mfi = merge_file(&o, &a, &b,
1001                                 branch1, branch2);
1002
1003                if (mfi.clean)
1004                        update_file(1, mfi.sha, mfi.mode, path);
1005                else {
1006                        clean_merge = 0;
1007                        output("CONFLICT (%s): Merge conflict in %s",
1008                                        reason, path);
1009
1010                        if (index_only)
1011                                update_file(0, mfi.sha, mfi.mode, path);
1012                        else
1013                                update_file_flags(mfi.sha, mfi.mode, path,
1014                                              0 /* update_cache */, 1 /* update_working_directory */);
1015                }
1016        } else
1017                die("Fatal merge failure, shouldn't happen.");
1018
1019        return clean_merge;
1020}
1021
1022static int merge_trees(struct tree *head,
1023                       struct tree *merge,
1024                       struct tree *common,
1025                       const char *branch1,
1026                       const char *branch2,
1027                       struct tree **result)
1028{
1029        int code, clean;
1030        if (sha_eq(common->object.sha1, merge->object.sha1)) {
1031                output("Already uptodate!");
1032                *result = head;
1033                return 1;
1034        }
1035
1036        code = git_merge_trees(index_only, common, head, merge);
1037
1038        if (code != 0)
1039                die("merging of trees %s and %s failed",
1040                    sha1_to_hex(head->object.sha1),
1041                    sha1_to_hex(merge->object.sha1));
1042
1043        if (unmerged_index()) {
1044                struct path_list *entries, *re_head, *re_merge;
1045                int i;
1046                path_list_clear(&current_file_set, 1);
1047                path_list_clear(&current_directory_set, 1);
1048                get_files_dirs(head);
1049                get_files_dirs(merge);
1050
1051                entries = get_unmerged();
1052                re_head  = get_renames(head, common, head, merge, entries);
1053                re_merge = get_renames(merge, common, head, merge, entries);
1054                clean = process_renames(re_head, re_merge,
1055                                branch1, branch2);
1056                for (i = 0; i < entries->nr; i++) {
1057                        const char *path = entries->items[i].path;
1058                        struct stage_data *e = entries->items[i].util;
1059                        if (e->processed)
1060                                continue;
1061                        if (!process_entry(path, e, branch1, branch2))
1062                                clean = 0;
1063                }
1064
1065                path_list_clear(re_merge, 0);
1066                path_list_clear(re_head, 0);
1067                path_list_clear(entries, 1);
1068
1069        } else {
1070                clean = 1;
1071                printf("merging of trees %s and %s resulted in %s\n",
1072                       sha1_to_hex(head->object.sha1),
1073                       sha1_to_hex(merge->object.sha1),
1074                       sha1_to_hex((*result)->object.sha1));
1075        }
1076        if (index_only)
1077                *result = git_write_tree();
1078
1079        return clean;
1080}
1081
1082static struct commit_list *reverse_commit_list(struct commit_list *list)
1083{
1084        struct commit_list *next = NULL, *current, *backup;
1085        for (current = list; current; current = backup) {
1086                backup = current->next;
1087                current->next = next;
1088                next = current;
1089        }
1090        return next;
1091}
1092
1093/*
1094 * Merge the commits h1 and h2, return the resulting virtual
1095 * commit object and a flag indicating the cleaness of the merge.
1096 */
1097static int merge(struct commit *h1,
1098                 struct commit *h2,
1099                 const char *branch1,
1100                 const char *branch2,
1101                 int call_depth /* =0 */,
1102                 struct commit_list *ca,
1103                 struct commit **result)
1104{
1105        struct commit_list *iter;
1106        struct commit *merged_common_ancestors;
1107        struct tree *mrtree;
1108        int clean;
1109
1110        output("Merging:");
1111        output_commit_title(h1);
1112        output_commit_title(h2);
1113
1114        if (!ca) {
1115                ca = get_merge_bases(h1, h2, 1);
1116                ca = reverse_commit_list(ca);
1117        }
1118
1119        output("found %u common ancestor(s):", commit_list_count(ca));
1120        for (iter = ca; iter; iter = iter->next)
1121                output_commit_title(iter->item);
1122
1123        merged_common_ancestors = pop_commit(&ca);
1124        if (merged_common_ancestors == NULL) {
1125                /* if there is no common ancestor, make an empty tree */
1126                struct tree *tree = xcalloc(1, sizeof(struct tree));
1127
1128                tree->object.parsed = 1;
1129                tree->object.type = OBJ_TREE;
1130                write_sha1_file(NULL, 0, tree_type, tree->object.sha1);
1131                merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1132        }
1133
1134        for (iter = ca; iter; iter = iter->next) {
1135                output_indent = call_depth + 1;
1136                /*
1137                 * When the merge fails, the result contains files
1138                 * with conflict markers. The cleanness flag is
1139                 * ignored, it was never acutally used, as result of
1140                 * merge_trees has always overwritten it: the commited
1141                 * "conflicts" were already resolved.
1142                 */
1143                discard_cache();
1144                merge(merged_common_ancestors, iter->item,
1145                      "Temporary merge branch 1",
1146                      "Temporary merge branch 2",
1147                      call_depth + 1,
1148                      NULL,
1149                      &merged_common_ancestors);
1150                output_indent = call_depth;
1151
1152                if (!merged_common_ancestors)
1153                        die("merge returned no commit");
1154        }
1155
1156        discard_cache();
1157        if (call_depth == 0) {
1158                read_cache();
1159                index_only = 0;
1160        } else
1161                index_only = 1;
1162
1163        clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1164                            branch1, branch2, &mrtree);
1165
1166        if (index_only) {
1167                *result = make_virtual_commit(mrtree, "merged tree");
1168                commit_list_insert(h1, &(*result)->parents);
1169                commit_list_insert(h2, &(*result)->parents->next);
1170        }
1171        return clean;
1172}
1173
1174static const char *better_branch_name(const char *branch)
1175{
1176        static char githead_env[8 + 40 + 1];
1177        char *name;
1178
1179        if (strlen(branch) != 40)
1180                return branch;
1181        sprintf(githead_env, "GITHEAD_%s", branch);
1182        name = getenv(githead_env);
1183        return name ? name : branch;
1184}
1185
1186static struct commit *get_ref(const char *ref)
1187{
1188        unsigned char sha1[20];
1189        struct object *object;
1190
1191        if (get_sha1(ref, sha1))
1192                die("Could not resolve ref '%s'", ref);
1193        object = deref_tag(parse_object(sha1), ref, strlen(ref));
1194        if (object->type == OBJ_TREE)
1195                return make_virtual_commit((struct tree*)object,
1196                        better_branch_name(ref));
1197        if (object->type != OBJ_COMMIT)
1198                return NULL;
1199        if (parse_commit((struct commit *)object))
1200                die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1201        return (struct commit *)object;
1202}
1203
1204int main(int argc, char *argv[])
1205{
1206        static const char *bases[20];
1207        static unsigned bases_count = 0;
1208        int i, clean;
1209        const char *branch1, *branch2;
1210        struct commit *result, *h1, *h2;
1211        struct commit_list *ca = NULL;
1212        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1213        int index_fd;
1214
1215        git_config(git_default_config); /* core.filemode */
1216
1217        if (argc < 4)
1218                die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1219
1220        for (i = 1; i < argc; ++i) {
1221                if (!strcmp(argv[i], "--"))
1222                        break;
1223                if (bases_count < sizeof(bases)/sizeof(*bases))
1224                        bases[bases_count++] = argv[i];
1225        }
1226        if (argc - i != 3) /* "--" "<head>" "<remote>" */
1227                die("Not handling anything other than two heads merge.");
1228
1229        branch1 = argv[++i];
1230        branch2 = argv[++i];
1231
1232        h1 = get_ref(branch1);
1233        h2 = get_ref(branch2);
1234
1235        branch1 = better_branch_name(branch1);
1236        branch2 = better_branch_name(branch2);
1237        printf("Merging %s with %s\n", branch1, branch2);
1238
1239        index_fd = hold_lock_file_for_update(lock, get_index_file(), 1);
1240
1241        for (i = 0; i < bases_count; i++) {
1242                struct commit *ancestor = get_ref(bases[i]);
1243                ca = commit_list_insert(ancestor, &ca);
1244        }
1245        clean = merge(h1, h2, branch1, branch2, 0, ca, &result);
1246
1247        if (active_cache_changed &&
1248            (write_cache(index_fd, active_cache, active_nr) ||
1249             close(index_fd) || commit_lock_file(lock)))
1250                        die ("unable to write %s", get_index_file());
1251
1252        return clean ? 0: 1;
1253}