unpack-trees.con commit git-svn: allow subset of branches/tags to be specified in glob spec (0757620)
   1#define NO_THE_INDEX_COMPATIBILITY_MACROS
   2#include "cache.h"
   3#include "dir.h"
   4#include "tree.h"
   5#include "tree-walk.h"
   6#include "cache-tree.h"
   7#include "unpack-trees.h"
   8#include "progress.h"
   9#include "refs.h"
  10#include "attr.h"
  11
  12/*
  13 * Error messages expected by scripts out of plumbing commands such as
  14 * read-tree.  Non-scripted Porcelain is not required to use these messages
  15 * and in fact are encouraged to reword them to better suit their particular
  16 * situation better.  See how "git checkout" replaces not_uptodate_file to
  17 * explain why it does not allow switching between branches when you have
  18 * local changes, for example.
  19 */
  20static struct unpack_trees_error_msgs unpack_plumbing_errors = {
  21        /* would_overwrite */
  22        "Entry '%s' would be overwritten by merge. Cannot merge.",
  23
  24        /* not_uptodate_file */
  25        "Entry '%s' not uptodate. Cannot merge.",
  26
  27        /* not_uptodate_dir */
  28        "Updating '%s' would lose untracked files in it",
  29
  30        /* would_lose_untracked */
  31        "Untracked working tree file '%s' would be %s by merge.",
  32
  33        /* bind_overlap */
  34        "Entry '%s' overlaps with '%s'.  Cannot bind.",
  35
  36        /* sparse_not_uptodate_file */
  37        "Entry '%s' not uptodate. Cannot update sparse checkout.",
  38
  39        /* would_lose_orphaned */
  40        "Working tree file '%s' would be %s by sparse checkout update.",
  41};
  42
  43#define ERRORMSG(o,fld) \
  44        ( ((o) && (o)->msgs.fld) \
  45        ? ((o)->msgs.fld) \
  46        : (unpack_plumbing_errors.fld) )
  47
  48static void add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
  49        unsigned int set, unsigned int clear)
  50{
  51        unsigned int size = ce_size(ce);
  52        struct cache_entry *new = xmalloc(size);
  53
  54        clear |= CE_HASHED | CE_UNHASHED;
  55
  56        memcpy(new, ce, size);
  57        new->next = NULL;
  58        new->ce_flags = (new->ce_flags & ~clear) | set;
  59        add_index_entry(&o->result, new, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
  60}
  61
  62/*
  63 * Unlink the last component and schedule the leading directories for
  64 * removal, such that empty directories get removed.
  65 */
  66static void unlink_entry(struct cache_entry *ce)
  67{
  68        if (has_symlink_or_noent_leading_path(ce->name, ce_namelen(ce)))
  69                return;
  70        if (S_ISGITLINK(ce->ce_mode)) {
  71                if (rmdir(ce->name)) {
  72                        warning("unable to rmdir %s: %s",
  73                                ce->name, strerror(errno));
  74                        return;
  75                }
  76        }
  77        else
  78                if (unlink_or_warn(ce->name))
  79                        return;
  80        schedule_dir_for_removal(ce->name, ce_namelen(ce));
  81}
  82
  83static struct checkout state;
  84static int check_updates(struct unpack_trees_options *o)
  85{
  86        unsigned cnt = 0, total = 0;
  87        struct progress *progress = NULL;
  88        struct index_state *index = &o->result;
  89        int i;
  90        int errs = 0;
  91
  92        if (o->update && o->verbose_update) {
  93                for (total = cnt = 0; cnt < index->cache_nr; cnt++) {
  94                        struct cache_entry *ce = index->cache[cnt];
  95                        if (ce->ce_flags & (CE_UPDATE | CE_REMOVE | CE_WT_REMOVE))
  96                                total++;
  97                }
  98
  99                progress = start_progress_delay("Checking out files",
 100                                                total, 50, 1);
 101                cnt = 0;
 102        }
 103
 104        if (o->update)
 105                git_attr_set_direction(GIT_ATTR_CHECKOUT, &o->result);
 106        for (i = 0; i < index->cache_nr; i++) {
 107                struct cache_entry *ce = index->cache[i];
 108
 109                if (ce->ce_flags & CE_WT_REMOVE) {
 110                        display_progress(progress, ++cnt);
 111                        if (o->update)
 112                                unlink_entry(ce);
 113                        continue;
 114                }
 115
 116                if (ce->ce_flags & CE_REMOVE) {
 117                        display_progress(progress, ++cnt);
 118                        if (o->update)
 119                                unlink_entry(ce);
 120                }
 121        }
 122        remove_marked_cache_entries(&o->result);
 123        remove_scheduled_dirs();
 124
 125        for (i = 0; i < index->cache_nr; i++) {
 126                struct cache_entry *ce = index->cache[i];
 127
 128                if (ce->ce_flags & CE_UPDATE) {
 129                        display_progress(progress, ++cnt);
 130                        ce->ce_flags &= ~CE_UPDATE;
 131                        if (o->update) {
 132                                errs |= checkout_entry(ce, &state, NULL);
 133                        }
 134                }
 135        }
 136        stop_progress(&progress);
 137        if (o->update)
 138                git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
 139        return errs != 0;
 140}
 141
 142static int verify_uptodate_sparse(struct cache_entry *ce, struct unpack_trees_options *o);
 143static int verify_absent_sparse(struct cache_entry *ce, const char *action, struct unpack_trees_options *o);
 144
 145static int will_have_skip_worktree(const struct cache_entry *ce, struct unpack_trees_options *o)
 146{
 147        const char *basename;
 148
 149        if (ce_stage(ce))
 150                return 0;
 151
 152        basename = strrchr(ce->name, '/');
 153        basename = basename ? basename+1 : ce->name;
 154        return excluded_from_list(ce->name, ce_namelen(ce), basename, NULL, o->el) <= 0;
 155}
 156
 157static int apply_sparse_checkout(struct cache_entry *ce, struct unpack_trees_options *o)
 158{
 159        int was_skip_worktree = ce_skip_worktree(ce);
 160
 161        if (will_have_skip_worktree(ce, o))
 162                ce->ce_flags |= CE_SKIP_WORKTREE;
 163        else
 164                ce->ce_flags &= ~CE_SKIP_WORKTREE;
 165
 166        /*
 167         * We only care about files getting into the checkout area
 168         * If merge strategies want to remove some, go ahead, this
 169         * flag will be removed eventually in unpack_trees() if it's
 170         * outside checkout area.
 171         */
 172        if (ce->ce_flags & CE_REMOVE)
 173                return 0;
 174
 175        if (!was_skip_worktree && ce_skip_worktree(ce)) {
 176                /*
 177                 * If CE_UPDATE is set, verify_uptodate() must be called already
 178                 * also stat info may have lost after merged_entry() so calling
 179                 * verify_uptodate() again may fail
 180                 */
 181                if (!(ce->ce_flags & CE_UPDATE) && verify_uptodate_sparse(ce, o))
 182                        return -1;
 183                ce->ce_flags |= CE_WT_REMOVE;
 184        }
 185        if (was_skip_worktree && !ce_skip_worktree(ce)) {
 186                if (verify_absent_sparse(ce, "overwritten", o))
 187                        return -1;
 188                ce->ce_flags |= CE_UPDATE;
 189        }
 190        return 0;
 191}
 192
 193static inline int call_unpack_fn(struct cache_entry **src, struct unpack_trees_options *o)
 194{
 195        int ret = o->fn(src, o);
 196        if (ret > 0)
 197                ret = 0;
 198        return ret;
 199}
 200
 201static int unpack_index_entry(struct cache_entry *ce, struct unpack_trees_options *o)
 202{
 203        struct cache_entry *src[5] = { ce, NULL, };
 204
 205        o->pos++;
 206        if (ce_stage(ce)) {
 207                if (o->skip_unmerged) {
 208                        add_entry(o, ce, 0, 0);
 209                        return 0;
 210                }
 211        }
 212        return call_unpack_fn(src, o);
 213}
 214
 215static int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long df_conflicts, struct name_entry *names, struct traverse_info *info)
 216{
 217        int i;
 218        struct tree_desc t[MAX_UNPACK_TREES];
 219        struct traverse_info newinfo;
 220        struct name_entry *p;
 221
 222        p = names;
 223        while (!p->mode)
 224                p++;
 225
 226        newinfo = *info;
 227        newinfo.prev = info;
 228        newinfo.name = *p;
 229        newinfo.pathlen += tree_entry_len(p->path, p->sha1) + 1;
 230        newinfo.conflicts |= df_conflicts;
 231
 232        for (i = 0; i < n; i++, dirmask >>= 1) {
 233                const unsigned char *sha1 = NULL;
 234                if (dirmask & 1)
 235                        sha1 = names[i].sha1;
 236                fill_tree_descriptor(t+i, sha1);
 237        }
 238        return traverse_trees(n, t, &newinfo);
 239}
 240
 241/*
 242 * Compare the traverse-path to the cache entry without actually
 243 * having to generate the textual representation of the traverse
 244 * path.
 245 *
 246 * NOTE! This *only* compares up to the size of the traverse path
 247 * itself - the caller needs to do the final check for the cache
 248 * entry having more data at the end!
 249 */
 250static int do_compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 251{
 252        int len, pathlen, ce_len;
 253        const char *ce_name;
 254
 255        if (info->prev) {
 256                int cmp = do_compare_entry(ce, info->prev, &info->name);
 257                if (cmp)
 258                        return cmp;
 259        }
 260        pathlen = info->pathlen;
 261        ce_len = ce_namelen(ce);
 262
 263        /* If ce_len < pathlen then we must have previously hit "name == directory" entry */
 264        if (ce_len < pathlen)
 265                return -1;
 266
 267        ce_len -= pathlen;
 268        ce_name = ce->name + pathlen;
 269
 270        len = tree_entry_len(n->path, n->sha1);
 271        return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 272}
 273
 274static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 275{
 276        int cmp = do_compare_entry(ce, info, n);
 277        if (cmp)
 278                return cmp;
 279
 280        /*
 281         * Even if the beginning compared identically, the ce should
 282         * compare as bigger than a directory leading up to it!
 283         */
 284        return ce_namelen(ce) > traverse_path_len(info, n);
 285}
 286
 287static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
 288{
 289        int len = traverse_path_len(info, n);
 290        struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
 291
 292        ce->ce_mode = create_ce_mode(n->mode);
 293        ce->ce_flags = create_ce_flags(len, stage);
 294        hashcpy(ce->sha1, n->sha1);
 295        make_traverse_path(ce->name, info, n);
 296
 297        return ce;
 298}
 299
 300static int unpack_nondirectories(int n, unsigned long mask,
 301                                 unsigned long dirmask,
 302                                 struct cache_entry **src,
 303                                 const struct name_entry *names,
 304                                 const struct traverse_info *info)
 305{
 306        int i;
 307        struct unpack_trees_options *o = info->data;
 308        unsigned long conflicts;
 309
 310        /* Do we have *only* directories? Nothing to do */
 311        if (mask == dirmask && !src[0])
 312                return 0;
 313
 314        conflicts = info->conflicts;
 315        if (o->merge)
 316                conflicts >>= 1;
 317        conflicts |= dirmask;
 318
 319        /*
 320         * Ok, we've filled in up to any potential index entry in src[0],
 321         * now do the rest.
 322         */
 323        for (i = 0; i < n; i++) {
 324                int stage;
 325                unsigned int bit = 1ul << i;
 326                if (conflicts & bit) {
 327                        src[i + o->merge] = o->df_conflict_entry;
 328                        continue;
 329                }
 330                if (!(mask & bit))
 331                        continue;
 332                if (!o->merge)
 333                        stage = 0;
 334                else if (i + 1 < o->head_idx)
 335                        stage = 1;
 336                else if (i + 1 > o->head_idx)
 337                        stage = 3;
 338                else
 339                        stage = 2;
 340                src[i + o->merge] = create_ce_entry(info, names + i, stage);
 341        }
 342
 343        if (o->merge)
 344                return call_unpack_fn(src, o);
 345
 346        for (i = 0; i < n; i++)
 347                if (src[i] && src[i] != o->df_conflict_entry)
 348                        add_entry(o, src[i], 0, 0);
 349        return 0;
 350}
 351
 352static int unpack_failed(struct unpack_trees_options *o, const char *message)
 353{
 354        discard_index(&o->result);
 355        if (!o->gently) {
 356                if (message)
 357                        return error("%s", message);
 358                return -1;
 359        }
 360        return -1;
 361}
 362
 363static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
 364{
 365        struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 366        struct unpack_trees_options *o = info->data;
 367        const struct name_entry *p = names;
 368
 369        /* Find first entry with a real name (we could use "mask" too) */
 370        while (!p->mode)
 371                p++;
 372
 373        /* Are we supposed to look at the index too? */
 374        if (o->merge) {
 375                while (o->pos < o->src_index->cache_nr) {
 376                        struct cache_entry *ce = o->src_index->cache[o->pos];
 377                        int cmp = compare_entry(ce, info, p);
 378                        if (cmp < 0) {
 379                                if (unpack_index_entry(ce, o) < 0)
 380                                        return unpack_failed(o, NULL);
 381                                continue;
 382                        }
 383                        if (!cmp) {
 384                                o->pos++;
 385                                if (ce_stage(ce)) {
 386                                        /*
 387                                         * If we skip unmerged index entries, we'll skip this
 388                                         * entry *and* the tree entries associated with it!
 389                                         */
 390                                        if (o->skip_unmerged) {
 391                                                add_entry(o, ce, 0, 0);
 392                                                return mask;
 393                                        }
 394                                }
 395                                src[0] = ce;
 396                        }
 397                        break;
 398                }
 399        }
 400
 401        if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
 402                return -1;
 403
 404        /* Now handle any directories.. */
 405        if (dirmask) {
 406                unsigned long conflicts = mask & ~dirmask;
 407                if (o->merge) {
 408                        conflicts <<= 1;
 409                        if (src[0])
 410                                conflicts |= 1;
 411                }
 412
 413                /* special case: "diff-index --cached" looking at a tree */
 414                if (o->diff_index_cached &&
 415                    n == 1 && dirmask == 1 && S_ISDIR(names->mode)) {
 416                        int matches;
 417                        matches = cache_tree_matches_traversal(o->src_index->cache_tree,
 418                                                               names, info);
 419                        /*
 420                         * Everything under the name matches.  Adjust o->pos to
 421                         * skip the entire hierarchy.
 422                         */
 423                        if (matches) {
 424                                o->pos += matches;
 425                                return mask;
 426                        }
 427                }
 428
 429                if (traverse_trees_recursive(n, dirmask, conflicts,
 430                                             names, info) < 0)
 431                        return -1;
 432                return mask;
 433        }
 434
 435        return mask;
 436}
 437
 438/*
 439 * N-way merge "len" trees.  Returns 0 on success, -1 on failure to manipulate the
 440 * resulting index, -2 on failure to reflect the changes to the work tree.
 441 */
 442int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
 443{
 444        int i, ret;
 445        static struct cache_entry *dfc;
 446        struct exclude_list el;
 447
 448        if (len > MAX_UNPACK_TREES)
 449                die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
 450        memset(&state, 0, sizeof(state));
 451        state.base_dir = "";
 452        state.force = 1;
 453        state.quiet = 1;
 454        state.refresh_cache = 1;
 455
 456        memset(&el, 0, sizeof(el));
 457        if (!core_apply_sparse_checkout || !o->update)
 458                o->skip_sparse_checkout = 1;
 459        if (!o->skip_sparse_checkout) {
 460                if (add_excludes_from_file_to_list(git_path("info/sparse-checkout"), "", 0, NULL, &el, 0) < 0)
 461                        o->skip_sparse_checkout = 1;
 462                else
 463                        o->el = &el;
 464        }
 465
 466        memset(&o->result, 0, sizeof(o->result));
 467        o->result.initialized = 1;
 468        if (o->src_index) {
 469                o->result.timestamp.sec = o->src_index->timestamp.sec;
 470                o->result.timestamp.nsec = o->src_index->timestamp.nsec;
 471        }
 472        o->merge_size = len;
 473
 474        if (!dfc)
 475                dfc = xcalloc(1, cache_entry_size(0));
 476        o->df_conflict_entry = dfc;
 477
 478        if (len) {
 479                const char *prefix = o->prefix ? o->prefix : "";
 480                struct traverse_info info;
 481
 482                setup_traverse_info(&info, prefix);
 483                info.fn = unpack_callback;
 484                info.data = o;
 485
 486                if (traverse_trees(len, t, &info) < 0) {
 487                        ret = unpack_failed(o, NULL);
 488                        goto done;
 489                }
 490        }
 491
 492        /* Any left-over entries in the index? */
 493        if (o->merge) {
 494                while (o->pos < o->src_index->cache_nr) {
 495                        struct cache_entry *ce = o->src_index->cache[o->pos];
 496                        if (unpack_index_entry(ce, o) < 0) {
 497                                ret = unpack_failed(o, NULL);
 498                                goto done;
 499                        }
 500                }
 501        }
 502
 503        if (o->trivial_merges_only && o->nontrivial_merge) {
 504                ret = unpack_failed(o, "Merge requires file-level merging");
 505                goto done;
 506        }
 507
 508        if (!o->skip_sparse_checkout) {
 509                int empty_worktree = 1;
 510                for (i = 0;i < o->result.cache_nr;i++) {
 511                        struct cache_entry *ce = o->result.cache[i];
 512
 513                        if (apply_sparse_checkout(ce, o)) {
 514                                ret = -1;
 515                                goto done;
 516                        }
 517                        /*
 518                         * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
 519                         * area as a result of ce_skip_worktree() shortcuts in
 520                         * verify_absent() and verify_uptodate(). Clear them.
 521                         */
 522                        if (ce_skip_worktree(ce))
 523                                ce->ce_flags &= ~(CE_UPDATE | CE_REMOVE);
 524                        else
 525                                empty_worktree = 0;
 526
 527                }
 528                if (o->result.cache_nr && empty_worktree) {
 529                        ret = unpack_failed(o, "Sparse checkout leaves no entry on working directory");
 530                        goto done;
 531                }
 532        }
 533
 534        o->src_index = NULL;
 535        ret = check_updates(o) ? (-2) : 0;
 536        if (o->dst_index)
 537                *o->dst_index = o->result;
 538
 539done:
 540        for (i = 0;i < el.nr;i++)
 541                free(el.excludes[i]);
 542        if (el.excludes)
 543                free(el.excludes);
 544
 545        return ret;
 546}
 547
 548/* Here come the merge functions */
 549
 550static int reject_merge(struct cache_entry *ce, struct unpack_trees_options *o)
 551{
 552        return error(ERRORMSG(o, would_overwrite), ce->name);
 553}
 554
 555static int same(struct cache_entry *a, struct cache_entry *b)
 556{
 557        if (!!a != !!b)
 558                return 0;
 559        if (!a && !b)
 560                return 1;
 561        if ((a->ce_flags | b->ce_flags) & CE_CONFLICTED)
 562                return 0;
 563        return a->ce_mode == b->ce_mode &&
 564               !hashcmp(a->sha1, b->sha1);
 565}
 566
 567
 568/*
 569 * When a CE gets turned into an unmerged entry, we
 570 * want it to be up-to-date
 571 */
 572static int verify_uptodate_1(struct cache_entry *ce,
 573                                   struct unpack_trees_options *o,
 574                                   const char *error_msg)
 575{
 576        struct stat st;
 577
 578        if (o->index_only || (!ce_skip_worktree(ce) && (o->reset || ce_uptodate(ce))))
 579                return 0;
 580
 581        if (!lstat(ce->name, &st)) {
 582                unsigned changed = ie_match_stat(o->src_index, ce, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
 583                if (!changed)
 584                        return 0;
 585                /*
 586                 * NEEDSWORK: the current default policy is to allow
 587                 * submodule to be out of sync wrt the supermodule
 588                 * index.  This needs to be tightened later for
 589                 * submodules that are marked to be automatically
 590                 * checked out.
 591                 */
 592                if (S_ISGITLINK(ce->ce_mode))
 593                        return 0;
 594                errno = 0;
 595        }
 596        if (errno == ENOENT)
 597                return 0;
 598        return o->gently ? -1 :
 599                error(error_msg, ce->name);
 600}
 601
 602static int verify_uptodate(struct cache_entry *ce,
 603                           struct unpack_trees_options *o)
 604{
 605        if (!o->skip_sparse_checkout && will_have_skip_worktree(ce, o))
 606                return 0;
 607        return verify_uptodate_1(ce, o, ERRORMSG(o, not_uptodate_file));
 608}
 609
 610static int verify_uptodate_sparse(struct cache_entry *ce,
 611                                  struct unpack_trees_options *o)
 612{
 613        return verify_uptodate_1(ce, o, ERRORMSG(o, sparse_not_uptodate_file));
 614}
 615
 616static void invalidate_ce_path(struct cache_entry *ce, struct unpack_trees_options *o)
 617{
 618        if (ce)
 619                cache_tree_invalidate_path(o->src_index->cache_tree, ce->name);
 620}
 621
 622/*
 623 * Check that checking out ce->sha1 in subdir ce->name is not
 624 * going to overwrite any working files.
 625 *
 626 * Currently, git does not checkout subprojects during a superproject
 627 * checkout, so it is not going to overwrite anything.
 628 */
 629static int verify_clean_submodule(struct cache_entry *ce, const char *action,
 630                                      struct unpack_trees_options *o)
 631{
 632        return 0;
 633}
 634
 635static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
 636                                      struct unpack_trees_options *o)
 637{
 638        /*
 639         * we are about to extract "ce->name"; we would not want to lose
 640         * anything in the existing directory there.
 641         */
 642        int namelen;
 643        int i;
 644        struct dir_struct d;
 645        char *pathbuf;
 646        int cnt = 0;
 647        unsigned char sha1[20];
 648
 649        if (S_ISGITLINK(ce->ce_mode) &&
 650            resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
 651                /* If we are not going to update the submodule, then
 652                 * we don't care.
 653                 */
 654                if (!hashcmp(sha1, ce->sha1))
 655                        return 0;
 656                return verify_clean_submodule(ce, action, o);
 657        }
 658
 659        /*
 660         * First let's make sure we do not have a local modification
 661         * in that directory.
 662         */
 663        namelen = strlen(ce->name);
 664        for (i = o->pos; i < o->src_index->cache_nr; i++) {
 665                struct cache_entry *ce2 = o->src_index->cache[i];
 666                int len = ce_namelen(ce2);
 667                if (len < namelen ||
 668                    strncmp(ce->name, ce2->name, namelen) ||
 669                    ce2->name[namelen] != '/')
 670                        break;
 671                /*
 672                 * ce2->name is an entry in the subdirectory.
 673                 */
 674                if (!ce_stage(ce2)) {
 675                        if (verify_uptodate(ce2, o))
 676                                return -1;
 677                        add_entry(o, ce2, CE_REMOVE, 0);
 678                }
 679                cnt++;
 680        }
 681
 682        /*
 683         * Then we need to make sure that we do not lose a locally
 684         * present file that is not ignored.
 685         */
 686        pathbuf = xmalloc(namelen + 2);
 687        memcpy(pathbuf, ce->name, namelen);
 688        strcpy(pathbuf+namelen, "/");
 689
 690        memset(&d, 0, sizeof(d));
 691        if (o->dir)
 692                d.exclude_per_dir = o->dir->exclude_per_dir;
 693        i = read_directory(&d, pathbuf, namelen+1, NULL);
 694        if (i)
 695                return o->gently ? -1 :
 696                        error(ERRORMSG(o, not_uptodate_dir), ce->name);
 697        free(pathbuf);
 698        return cnt;
 699}
 700
 701/*
 702 * This gets called when there was no index entry for the tree entry 'dst',
 703 * but we found a file in the working tree that 'lstat()' said was fine,
 704 * and we're on a case-insensitive filesystem.
 705 *
 706 * See if we can find a case-insensitive match in the index that also
 707 * matches the stat information, and assume it's that other file!
 708 */
 709static int icase_exists(struct unpack_trees_options *o, struct cache_entry *dst, struct stat *st)
 710{
 711        struct cache_entry *src;
 712
 713        src = index_name_exists(o->src_index, dst->name, ce_namelen(dst), 1);
 714        return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
 715}
 716
 717/*
 718 * We do not want to remove or overwrite a working tree file that
 719 * is not tracked, unless it is ignored.
 720 */
 721static int verify_absent_1(struct cache_entry *ce, const char *action,
 722                                 struct unpack_trees_options *o,
 723                                 const char *error_msg)
 724{
 725        struct stat st;
 726
 727        if (o->index_only || o->reset || !o->update)
 728                return 0;
 729
 730        if (has_symlink_or_noent_leading_path(ce->name, ce_namelen(ce)))
 731                return 0;
 732
 733        if (!lstat(ce->name, &st)) {
 734                int ret;
 735                int dtype = ce_to_dtype(ce);
 736                struct cache_entry *result;
 737
 738                /*
 739                 * It may be that the 'lstat()' succeeded even though
 740                 * target 'ce' was absent, because there is an old
 741                 * entry that is different only in case..
 742                 *
 743                 * Ignore that lstat() if it matches.
 744                 */
 745                if (ignore_case && icase_exists(o, ce, &st))
 746                        return 0;
 747
 748                if (o->dir && excluded(o->dir, ce->name, &dtype))
 749                        /*
 750                         * ce->name is explicitly excluded, so it is Ok to
 751                         * overwrite it.
 752                         */
 753                        return 0;
 754                if (S_ISDIR(st.st_mode)) {
 755                        /*
 756                         * We are checking out path "foo" and
 757                         * found "foo/." in the working tree.
 758                         * This is tricky -- if we have modified
 759                         * files that are in "foo/" we would lose
 760                         * them.
 761                         */
 762                        ret = verify_clean_subdirectory(ce, action, o);
 763                        if (ret < 0)
 764                                return ret;
 765
 766                        /*
 767                         * If this removed entries from the index,
 768                         * what that means is:
 769                         *
 770                         * (1) the caller unpack_callback() saw path/foo
 771                         * in the index, and it has not removed it because
 772                         * it thinks it is handling 'path' as blob with
 773                         * D/F conflict;
 774                         * (2) we will return "ok, we placed a merged entry
 775                         * in the index" which would cause o->pos to be
 776                         * incremented by one;
 777                         * (3) however, original o->pos now has 'path/foo'
 778                         * marked with "to be removed".
 779                         *
 780                         * We need to increment it by the number of
 781                         * deleted entries here.
 782                         */
 783                        o->pos += ret;
 784                        return 0;
 785                }
 786
 787                /*
 788                 * The previous round may already have decided to
 789                 * delete this path, which is in a subdirectory that
 790                 * is being replaced with a blob.
 791                 */
 792                result = index_name_exists(&o->result, ce->name, ce_namelen(ce), 0);
 793                if (result) {
 794                        if (result->ce_flags & CE_REMOVE)
 795                                return 0;
 796                }
 797
 798                return o->gently ? -1 :
 799                        error(ERRORMSG(o, would_lose_untracked), ce->name, action);
 800        }
 801        return 0;
 802}
 803static int verify_absent(struct cache_entry *ce, const char *action,
 804                         struct unpack_trees_options *o)
 805{
 806        if (!o->skip_sparse_checkout && will_have_skip_worktree(ce, o))
 807                return 0;
 808        return verify_absent_1(ce, action, o, ERRORMSG(o, would_lose_untracked));
 809}
 810
 811static int verify_absent_sparse(struct cache_entry *ce, const char *action,
 812                         struct unpack_trees_options *o)
 813{
 814        return verify_absent_1(ce, action, o, ERRORMSG(o, would_lose_orphaned));
 815}
 816
 817static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
 818                struct unpack_trees_options *o)
 819{
 820        int update = CE_UPDATE;
 821
 822        if (!old) {
 823                if (verify_absent(merge, "overwritten", o))
 824                        return -1;
 825                invalidate_ce_path(merge, o);
 826        } else if (!(old->ce_flags & CE_CONFLICTED)) {
 827                /*
 828                 * See if we can re-use the old CE directly?
 829                 * That way we get the uptodate stat info.
 830                 *
 831                 * This also removes the UPDATE flag on a match; otherwise
 832                 * we will end up overwriting local changes in the work tree.
 833                 */
 834                if (same(old, merge)) {
 835                        copy_cache_entry(merge, old);
 836                        update = 0;
 837                } else {
 838                        if (verify_uptodate(old, o))
 839                                return -1;
 840                        if (ce_skip_worktree(old))
 841                                update |= CE_SKIP_WORKTREE;
 842                        invalidate_ce_path(old, o);
 843                }
 844        } else {
 845                /*
 846                 * Previously unmerged entry left as an existence
 847                 * marker by read_index_unmerged();
 848                 */
 849                invalidate_ce_path(old, o);
 850        }
 851
 852        add_entry(o, merge, update, CE_STAGEMASK);
 853        return 1;
 854}
 855
 856static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
 857                struct unpack_trees_options *o)
 858{
 859        /* Did it exist in the index? */
 860        if (!old) {
 861                if (verify_absent(ce, "removed", o))
 862                        return -1;
 863                return 0;
 864        }
 865        if (!(old->ce_flags & CE_CONFLICTED) && verify_uptodate(old, o))
 866                return -1;
 867        add_entry(o, ce, CE_REMOVE, 0);
 868        invalidate_ce_path(ce, o);
 869        return 1;
 870}
 871
 872static int keep_entry(struct cache_entry *ce, struct unpack_trees_options *o)
 873{
 874        add_entry(o, ce, 0, 0);
 875        return 1;
 876}
 877
 878#if DBRT_DEBUG
 879static void show_stage_entry(FILE *o,
 880                             const char *label, const struct cache_entry *ce)
 881{
 882        if (!ce)
 883                fprintf(o, "%s (missing)\n", label);
 884        else
 885                fprintf(o, "%s%06o %s %d\t%s\n",
 886                        label,
 887                        ce->ce_mode,
 888                        sha1_to_hex(ce->sha1),
 889                        ce_stage(ce),
 890                        ce->name);
 891}
 892#endif
 893
 894int threeway_merge(struct cache_entry **stages, struct unpack_trees_options *o)
 895{
 896        struct cache_entry *index;
 897        struct cache_entry *head;
 898        struct cache_entry *remote = stages[o->head_idx + 1];
 899        int count;
 900        int head_match = 0;
 901        int remote_match = 0;
 902
 903        int df_conflict_head = 0;
 904        int df_conflict_remote = 0;
 905
 906        int any_anc_missing = 0;
 907        int no_anc_exists = 1;
 908        int i;
 909
 910        for (i = 1; i < o->head_idx; i++) {
 911                if (!stages[i] || stages[i] == o->df_conflict_entry)
 912                        any_anc_missing = 1;
 913                else
 914                        no_anc_exists = 0;
 915        }
 916
 917        index = stages[0];
 918        head = stages[o->head_idx];
 919
 920        if (head == o->df_conflict_entry) {
 921                df_conflict_head = 1;
 922                head = NULL;
 923        }
 924
 925        if (remote == o->df_conflict_entry) {
 926                df_conflict_remote = 1;
 927                remote = NULL;
 928        }
 929
 930        /* First, if there's a #16 situation, note that to prevent #13
 931         * and #14.
 932         */
 933        if (!same(remote, head)) {
 934                for (i = 1; i < o->head_idx; i++) {
 935                        if (same(stages[i], head)) {
 936                                head_match = i;
 937                        }
 938                        if (same(stages[i], remote)) {
 939                                remote_match = i;
 940                        }
 941                }
 942        }
 943
 944        /* We start with cases where the index is allowed to match
 945         * something other than the head: #14(ALT) and #2ALT, where it
 946         * is permitted to match the result instead.
 947         */
 948        /* #14, #14ALT, #2ALT */
 949        if (remote && !df_conflict_head && head_match && !remote_match) {
 950                if (index && !same(index, remote) && !same(index, head))
 951                        return o->gently ? -1 : reject_merge(index, o);
 952                return merged_entry(remote, index, o);
 953        }
 954        /*
 955         * If we have an entry in the index cache, then we want to
 956         * make sure that it matches head.
 957         */
 958        if (index && !same(index, head))
 959                return o->gently ? -1 : reject_merge(index, o);
 960
 961        if (head) {
 962                /* #5ALT, #15 */
 963                if (same(head, remote))
 964                        return merged_entry(head, index, o);
 965                /* #13, #3ALT */
 966                if (!df_conflict_remote && remote_match && !head_match)
 967                        return merged_entry(head, index, o);
 968        }
 969
 970        /* #1 */
 971        if (!head && !remote && any_anc_missing)
 972                return 0;
 973
 974        /* Under the new "aggressive" rule, we resolve mostly trivial
 975         * cases that we historically had git-merge-one-file resolve.
 976         */
 977        if (o->aggressive) {
 978                int head_deleted = !head && !df_conflict_head;
 979                int remote_deleted = !remote && !df_conflict_remote;
 980                struct cache_entry *ce = NULL;
 981
 982                if (index)
 983                        ce = index;
 984                else if (head)
 985                        ce = head;
 986                else if (remote)
 987                        ce = remote;
 988                else {
 989                        for (i = 1; i < o->head_idx; i++) {
 990                                if (stages[i] && stages[i] != o->df_conflict_entry) {
 991                                        ce = stages[i];
 992                                        break;
 993                                }
 994                        }
 995                }
 996
 997                /*
 998                 * Deleted in both.
 999                 * Deleted in one and unchanged in the other.
1000                 */
1001                if ((head_deleted && remote_deleted) ||
1002                    (head_deleted && remote && remote_match) ||
1003                    (remote_deleted && head && head_match)) {
1004                        if (index)
1005                                return deleted_entry(index, index, o);
1006                        if (ce && !head_deleted) {
1007                                if (verify_absent(ce, "removed", o))
1008                                        return -1;
1009                        }
1010                        return 0;
1011                }
1012                /*
1013                 * Added in both, identically.
1014                 */
1015                if (no_anc_exists && head && remote && same(head, remote))
1016                        return merged_entry(head, index, o);
1017
1018        }
1019
1020        /* Below are "no merge" cases, which require that the index be
1021         * up-to-date to avoid the files getting overwritten with
1022         * conflict resolution files.
1023         */
1024        if (index) {
1025                if (verify_uptodate(index, o))
1026                        return -1;
1027        }
1028
1029        o->nontrivial_merge = 1;
1030
1031        /* #2, #3, #4, #6, #7, #9, #10, #11. */
1032        count = 0;
1033        if (!head_match || !remote_match) {
1034                for (i = 1; i < o->head_idx; i++) {
1035                        if (stages[i] && stages[i] != o->df_conflict_entry) {
1036                                keep_entry(stages[i], o);
1037                                count++;
1038                                break;
1039                        }
1040                }
1041        }
1042#if DBRT_DEBUG
1043        else {
1044                fprintf(stderr, "read-tree: warning #16 detected\n");
1045                show_stage_entry(stderr, "head   ", stages[head_match]);
1046                show_stage_entry(stderr, "remote ", stages[remote_match]);
1047        }
1048#endif
1049        if (head) { count += keep_entry(head, o); }
1050        if (remote) { count += keep_entry(remote, o); }
1051        return count;
1052}
1053
1054/*
1055 * Two-way merge.
1056 *
1057 * The rule is to "carry forward" what is in the index without losing
1058 * information across a "fast-forward", favoring a successful merge
1059 * over a merge failure when it makes sense.  For details of the
1060 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
1061 *
1062 */
1063int twoway_merge(struct cache_entry **src, struct unpack_trees_options *o)
1064{
1065        struct cache_entry *current = src[0];
1066        struct cache_entry *oldtree = src[1];
1067        struct cache_entry *newtree = src[2];
1068
1069        if (o->merge_size != 2)
1070                return error("Cannot do a twoway merge of %d trees",
1071                             o->merge_size);
1072
1073        if (oldtree == o->df_conflict_entry)
1074                oldtree = NULL;
1075        if (newtree == o->df_conflict_entry)
1076                newtree = NULL;
1077
1078        if (current) {
1079                if ((!oldtree && !newtree) || /* 4 and 5 */
1080                    (!oldtree && newtree &&
1081                     same(current, newtree)) || /* 6 and 7 */
1082                    (oldtree && newtree &&
1083                     same(oldtree, newtree)) || /* 14 and 15 */
1084                    (oldtree && newtree &&
1085                     !same(oldtree, newtree) && /* 18 and 19 */
1086                     same(current, newtree))) {
1087                        return keep_entry(current, o);
1088                }
1089                else if (oldtree && !newtree && same(current, oldtree)) {
1090                        /* 10 or 11 */
1091                        return deleted_entry(oldtree, current, o);
1092                }
1093                else if (oldtree && newtree &&
1094                         same(current, oldtree) && !same(current, newtree)) {
1095                        /* 20 or 21 */
1096                        return merged_entry(newtree, current, o);
1097                }
1098                else {
1099                        /* all other failures */
1100                        if (oldtree)
1101                                return o->gently ? -1 : reject_merge(oldtree, o);
1102                        if (current)
1103                                return o->gently ? -1 : reject_merge(current, o);
1104                        if (newtree)
1105                                return o->gently ? -1 : reject_merge(newtree, o);
1106                        return -1;
1107                }
1108        }
1109        else if (newtree) {
1110                if (oldtree && !o->initial_checkout) {
1111                        /*
1112                         * deletion of the path was staged;
1113                         */
1114                        if (same(oldtree, newtree))
1115                                return 1;
1116                        return reject_merge(oldtree, o);
1117                }
1118                return merged_entry(newtree, current, o);
1119        }
1120        return deleted_entry(oldtree, current, o);
1121}
1122
1123/*
1124 * Bind merge.
1125 *
1126 * Keep the index entries at stage0, collapse stage1 but make sure
1127 * stage0 does not have anything there.
1128 */
1129int bind_merge(struct cache_entry **src,
1130                struct unpack_trees_options *o)
1131{
1132        struct cache_entry *old = src[0];
1133        struct cache_entry *a = src[1];
1134
1135        if (o->merge_size != 1)
1136                return error("Cannot do a bind merge of %d trees\n",
1137                             o->merge_size);
1138        if (a && old)
1139                return o->gently ? -1 :
1140                        error(ERRORMSG(o, bind_overlap), a->name, old->name);
1141        if (!a)
1142                return keep_entry(old, o);
1143        else
1144                return merged_entry(a, NULL, o);
1145}
1146
1147/*
1148 * One-way merge.
1149 *
1150 * The rule is:
1151 * - take the stat information from stage0, take the data from stage1
1152 */
1153int oneway_merge(struct cache_entry **src, struct unpack_trees_options *o)
1154{
1155        struct cache_entry *old = src[0];
1156        struct cache_entry *a = src[1];
1157
1158        if (o->merge_size != 1)
1159                return error("Cannot do a oneway merge of %d trees",
1160                             o->merge_size);
1161
1162        if (!a || a == o->df_conflict_entry)
1163                return deleted_entry(old, old, o);
1164
1165        if (old && same(old, a)) {
1166                int update = 0;
1167                if (o->reset && !ce_uptodate(old) && !ce_skip_worktree(old)) {
1168                        struct stat st;
1169                        if (lstat(old->name, &st) ||
1170                            ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
1171                                update |= CE_UPDATE;
1172                }
1173                add_entry(o, old, update, 0);
1174                return 0;
1175        }
1176        return merged_entry(a, old, o);
1177}