unpack-trees.con commit Merge branch 'nd/rebase-show-current-patch' (9ca488c)
   1#define NO_THE_INDEX_COMPATIBILITY_MACROS
   2#include "cache.h"
   3#include "repository.h"
   4#include "config.h"
   5#include "dir.h"
   6#include "tree.h"
   7#include "tree-walk.h"
   8#include "cache-tree.h"
   9#include "unpack-trees.h"
  10#include "progress.h"
  11#include "refs.h"
  12#include "attr.h"
  13#include "split-index.h"
  14#include "dir.h"
  15#include "submodule.h"
  16#include "submodule-config.h"
  17#include "fsmonitor.h"
  18#include "fetch-object.h"
  19
  20/*
  21 * Error messages expected by scripts out of plumbing commands such as
  22 * read-tree.  Non-scripted Porcelain is not required to use these messages
  23 * and in fact are encouraged to reword them to better suit their particular
  24 * situation better.  See how "git checkout" and "git merge" replaces
  25 * them using setup_unpack_trees_porcelain(), for example.
  26 */
  27static const char *unpack_plumbing_errors[NB_UNPACK_TREES_ERROR_TYPES] = {
  28        /* ERROR_WOULD_OVERWRITE */
  29        "Entry '%s' would be overwritten by merge. Cannot merge.",
  30
  31        /* ERROR_NOT_UPTODATE_FILE */
  32        "Entry '%s' not uptodate. Cannot merge.",
  33
  34        /* ERROR_NOT_UPTODATE_DIR */
  35        "Updating '%s' would lose untracked files in it",
  36
  37        /* ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN */
  38        "Untracked working tree file '%s' would be overwritten by merge.",
  39
  40        /* ERROR_WOULD_LOSE_UNTRACKED_REMOVED */
  41        "Untracked working tree file '%s' would be removed by merge.",
  42
  43        /* ERROR_BIND_OVERLAP */
  44        "Entry '%s' overlaps with '%s'.  Cannot bind.",
  45
  46        /* ERROR_SPARSE_NOT_UPTODATE_FILE */
  47        "Entry '%s' not uptodate. Cannot update sparse checkout.",
  48
  49        /* ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN */
  50        "Working tree file '%s' would be overwritten by sparse checkout update.",
  51
  52        /* ERROR_WOULD_LOSE_ORPHANED_REMOVED */
  53        "Working tree file '%s' would be removed by sparse checkout update.",
  54
  55        /* ERROR_WOULD_LOSE_SUBMODULE */
  56        "Submodule '%s' cannot checkout new HEAD.",
  57};
  58
  59#define ERRORMSG(o,type) \
  60        ( ((o) && (o)->msgs[(type)]) \
  61          ? ((o)->msgs[(type)])      \
  62          : (unpack_plumbing_errors[(type)]) )
  63
  64static const char *super_prefixed(const char *path)
  65{
  66        /*
  67         * It is necessary and sufficient to have two static buffers
  68         * here, as the return value of this function is fed to
  69         * error() using the unpack_*_errors[] templates we see above.
  70         */
  71        static struct strbuf buf[2] = {STRBUF_INIT, STRBUF_INIT};
  72        static int super_prefix_len = -1;
  73        static unsigned idx = ARRAY_SIZE(buf) - 1;
  74
  75        if (super_prefix_len < 0) {
  76                const char *super_prefix = get_super_prefix();
  77                if (!super_prefix) {
  78                        super_prefix_len = 0;
  79                } else {
  80                        int i;
  81                        for (i = 0; i < ARRAY_SIZE(buf); i++)
  82                                strbuf_addstr(&buf[i], super_prefix);
  83                        super_prefix_len = buf[0].len;
  84                }
  85        }
  86
  87        if (!super_prefix_len)
  88                return path;
  89
  90        if (++idx >= ARRAY_SIZE(buf))
  91                idx = 0;
  92
  93        strbuf_setlen(&buf[idx], super_prefix_len);
  94        strbuf_addstr(&buf[idx], path);
  95
  96        return buf[idx].buf;
  97}
  98
  99void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
 100                                  const char *cmd)
 101{
 102        int i;
 103        const char **msgs = opts->msgs;
 104        const char *msg;
 105
 106        if (!strcmp(cmd, "checkout"))
 107                msg = advice_commit_before_merge
 108                      ? _("Your local changes to the following files would be overwritten by checkout:\n%%s"
 109                          "Please commit your changes or stash them before you switch branches.")
 110                      : _("Your local changes to the following files would be overwritten by checkout:\n%%s");
 111        else if (!strcmp(cmd, "merge"))
 112                msg = advice_commit_before_merge
 113                      ? _("Your local changes to the following files would be overwritten by merge:\n%%s"
 114                          "Please commit your changes or stash them before you merge.")
 115                      : _("Your local changes to the following files would be overwritten by merge:\n%%s");
 116        else
 117                msg = advice_commit_before_merge
 118                      ? _("Your local changes to the following files would be overwritten by %s:\n%%s"
 119                          "Please commit your changes or stash them before you %s.")
 120                      : _("Your local changes to the following files would be overwritten by %s:\n%%s");
 121        msgs[ERROR_WOULD_OVERWRITE] = msgs[ERROR_NOT_UPTODATE_FILE] =
 122                xstrfmt(msg, cmd, cmd);
 123
 124        msgs[ERROR_NOT_UPTODATE_DIR] =
 125                _("Updating the following directories would lose untracked files in them:\n%s");
 126
 127        if (!strcmp(cmd, "checkout"))
 128                msg = advice_commit_before_merge
 129                      ? _("The following untracked working tree files would be removed by checkout:\n%%s"
 130                          "Please move or remove them before you switch branches.")
 131                      : _("The following untracked working tree files would be removed by checkout:\n%%s");
 132        else if (!strcmp(cmd, "merge"))
 133                msg = advice_commit_before_merge
 134                      ? _("The following untracked working tree files would be removed by merge:\n%%s"
 135                          "Please move or remove them before you merge.")
 136                      : _("The following untracked working tree files would be removed by merge:\n%%s");
 137        else
 138                msg = advice_commit_before_merge
 139                      ? _("The following untracked working tree files would be removed by %s:\n%%s"
 140                          "Please move or remove them before you %s.")
 141                      : _("The following untracked working tree files would be removed by %s:\n%%s");
 142        msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = xstrfmt(msg, cmd, cmd);
 143
 144        if (!strcmp(cmd, "checkout"))
 145                msg = advice_commit_before_merge
 146                      ? _("The following untracked working tree files would be overwritten by checkout:\n%%s"
 147                          "Please move or remove them before you switch branches.")
 148                      : _("The following untracked working tree files would be overwritten by checkout:\n%%s");
 149        else if (!strcmp(cmd, "merge"))
 150                msg = advice_commit_before_merge
 151                      ? _("The following untracked working tree files would be overwritten by merge:\n%%s"
 152                          "Please move or remove them before you merge.")
 153                      : _("The following untracked working tree files would be overwritten by merge:\n%%s");
 154        else
 155                msg = advice_commit_before_merge
 156                      ? _("The following untracked working tree files would be overwritten by %s:\n%%s"
 157                          "Please move or remove them before you %s.")
 158                      : _("The following untracked working tree files would be overwritten by %s:\n%%s");
 159        msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = xstrfmt(msg, cmd, cmd);
 160
 161        /*
 162         * Special case: ERROR_BIND_OVERLAP refers to a pair of paths, we
 163         * cannot easily display it as a list.
 164         */
 165        msgs[ERROR_BIND_OVERLAP] = _("Entry '%s' overlaps with '%s'.  Cannot bind.");
 166
 167        msgs[ERROR_SPARSE_NOT_UPTODATE_FILE] =
 168                _("Cannot update sparse checkout: the following entries are not up to date:\n%s");
 169        msgs[ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN] =
 170                _("The following working tree files would be overwritten by sparse checkout update:\n%s");
 171        msgs[ERROR_WOULD_LOSE_ORPHANED_REMOVED] =
 172                _("The following working tree files would be removed by sparse checkout update:\n%s");
 173        msgs[ERROR_WOULD_LOSE_SUBMODULE] =
 174                _("Cannot update submodule:\n%s");
 175
 176        opts->show_all_errors = 1;
 177        /* rejected paths may not have a static buffer */
 178        for (i = 0; i < ARRAY_SIZE(opts->unpack_rejects); i++)
 179                opts->unpack_rejects[i].strdup_strings = 1;
 180}
 181
 182static int do_add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
 183                         unsigned int set, unsigned int clear)
 184{
 185        clear |= CE_HASHED;
 186
 187        if (set & CE_REMOVE)
 188                set |= CE_WT_REMOVE;
 189
 190        ce->ce_flags = (ce->ce_flags & ~clear) | set;
 191        return add_index_entry(&o->result, ce,
 192                               ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 193}
 194
 195static struct cache_entry *dup_entry(const struct cache_entry *ce)
 196{
 197        unsigned int size = ce_size(ce);
 198        struct cache_entry *new = xmalloc(size);
 199
 200        memcpy(new, ce, size);
 201        return new;
 202}
 203
 204static void add_entry(struct unpack_trees_options *o,
 205                      const struct cache_entry *ce,
 206                      unsigned int set, unsigned int clear)
 207{
 208        do_add_entry(o, dup_entry(ce), set, clear);
 209}
 210
 211/*
 212 * add error messages on path <path>
 213 * corresponding to the type <e> with the message <msg>
 214 * indicating if it should be display in porcelain or not
 215 */
 216static int add_rejected_path(struct unpack_trees_options *o,
 217                             enum unpack_trees_error_types e,
 218                             const char *path)
 219{
 220        if (!o->show_all_errors)
 221                return error(ERRORMSG(o, e), super_prefixed(path));
 222
 223        /*
 224         * Otherwise, insert in a list for future display by
 225         * display_error_msgs()
 226         */
 227        string_list_append(&o->unpack_rejects[e], path);
 228        return -1;
 229}
 230
 231/*
 232 * display all the error messages stored in a nice way
 233 */
 234static void display_error_msgs(struct unpack_trees_options *o)
 235{
 236        int e, i;
 237        int something_displayed = 0;
 238        for (e = 0; e < NB_UNPACK_TREES_ERROR_TYPES; e++) {
 239                struct string_list *rejects = &o->unpack_rejects[e];
 240                if (rejects->nr > 0) {
 241                        struct strbuf path = STRBUF_INIT;
 242                        something_displayed = 1;
 243                        for (i = 0; i < rejects->nr; i++)
 244                                strbuf_addf(&path, "\t%s\n", rejects->items[i].string);
 245                        error(ERRORMSG(o, e), super_prefixed(path.buf));
 246                        strbuf_release(&path);
 247                }
 248                string_list_clear(rejects, 0);
 249        }
 250        if (something_displayed)
 251                fprintf(stderr, _("Aborting\n"));
 252}
 253
 254static int check_submodule_move_head(const struct cache_entry *ce,
 255                                     const char *old_id,
 256                                     const char *new_id,
 257                                     struct unpack_trees_options *o)
 258{
 259        unsigned flags = SUBMODULE_MOVE_HEAD_DRY_RUN;
 260        const struct submodule *sub = submodule_from_ce(ce);
 261
 262        if (!sub)
 263                return 0;
 264
 265        if (o->reset)
 266                flags |= SUBMODULE_MOVE_HEAD_FORCE;
 267
 268        if (submodule_move_head(ce->name, old_id, new_id, flags))
 269                return o->gently ? -1 :
 270                                   add_rejected_path(o, ERROR_WOULD_LOSE_SUBMODULE, ce->name);
 271        return 0;
 272}
 273
 274/*
 275 * Preform the loading of the repository's gitmodules file.  This function is
 276 * used by 'check_update()' to perform loading of the gitmodules file in two
 277 * differnt situations:
 278 * (1) before removing entries from the working tree if the gitmodules file has
 279 *     been marked for removal.  This situation is specified by 'state' == NULL.
 280 * (2) before checking out entries to the working tree if the gitmodules file
 281 *     has been marked for update.  This situation is specified by 'state' != NULL.
 282 */
 283static void load_gitmodules_file(struct index_state *index,
 284                                 struct checkout *state)
 285{
 286        int pos = index_name_pos(index, GITMODULES_FILE, strlen(GITMODULES_FILE));
 287
 288        if (pos >= 0) {
 289                struct cache_entry *ce = index->cache[pos];
 290                if (!state && ce->ce_flags & CE_WT_REMOVE) {
 291                        repo_read_gitmodules(the_repository);
 292                } else if (state && (ce->ce_flags & CE_UPDATE)) {
 293                        submodule_free();
 294                        checkout_entry(ce, state, NULL);
 295                        repo_read_gitmodules(the_repository);
 296                }
 297        }
 298}
 299
 300/*
 301 * Unlink the last component and schedule the leading directories for
 302 * removal, such that empty directories get removed.
 303 */
 304static void unlink_entry(const struct cache_entry *ce)
 305{
 306        const struct submodule *sub = submodule_from_ce(ce);
 307        if (sub) {
 308                /* state.force is set at the caller. */
 309                submodule_move_head(ce->name, "HEAD", NULL,
 310                                    SUBMODULE_MOVE_HEAD_FORCE);
 311        }
 312        if (!check_leading_path(ce->name, ce_namelen(ce)))
 313                return;
 314        if (remove_or_warn(ce->ce_mode, ce->name))
 315                return;
 316        schedule_dir_for_removal(ce->name, ce_namelen(ce));
 317}
 318
 319static struct progress *get_progress(struct unpack_trees_options *o)
 320{
 321        unsigned cnt = 0, total = 0;
 322        struct index_state *index = &o->result;
 323
 324        if (!o->update || !o->verbose_update)
 325                return NULL;
 326
 327        for (; cnt < index->cache_nr; cnt++) {
 328                const struct cache_entry *ce = index->cache[cnt];
 329                if (ce->ce_flags & (CE_UPDATE | CE_WT_REMOVE))
 330                        total++;
 331        }
 332
 333        return start_delayed_progress(_("Checking out files"), total);
 334}
 335
 336static int check_updates(struct unpack_trees_options *o)
 337{
 338        unsigned cnt = 0;
 339        int errs = 0;
 340        struct progress *progress = NULL;
 341        struct index_state *index = &o->result;
 342        struct checkout state = CHECKOUT_INIT;
 343        int i;
 344
 345        state.force = 1;
 346        state.quiet = 1;
 347        state.refresh_cache = 1;
 348        state.istate = index;
 349
 350        progress = get_progress(o);
 351
 352        if (o->update)
 353                git_attr_set_direction(GIT_ATTR_CHECKOUT, index);
 354
 355        if (should_update_submodules() && o->update && !o->dry_run)
 356                load_gitmodules_file(index, NULL);
 357
 358        for (i = 0; i < index->cache_nr; i++) {
 359                const struct cache_entry *ce = index->cache[i];
 360
 361                if (ce->ce_flags & CE_WT_REMOVE) {
 362                        display_progress(progress, ++cnt);
 363                        if (o->update && !o->dry_run)
 364                                unlink_entry(ce);
 365                }
 366        }
 367        remove_marked_cache_entries(index);
 368        remove_scheduled_dirs();
 369
 370        if (should_update_submodules() && o->update && !o->dry_run)
 371                load_gitmodules_file(index, &state);
 372
 373        enable_delayed_checkout(&state);
 374        if (repository_format_partial_clone && o->update && !o->dry_run) {
 375                /*
 376                 * Prefetch the objects that are to be checked out in the loop
 377                 * below.
 378                 */
 379                struct oid_array to_fetch = OID_ARRAY_INIT;
 380                int fetch_if_missing_store = fetch_if_missing;
 381                fetch_if_missing = 0;
 382                for (i = 0; i < index->cache_nr; i++) {
 383                        struct cache_entry *ce = index->cache[i];
 384                        if ((ce->ce_flags & CE_UPDATE) &&
 385                            !S_ISGITLINK(ce->ce_mode)) {
 386                                if (!has_object_file(&ce->oid))
 387                                        oid_array_append(&to_fetch, &ce->oid);
 388                        }
 389                }
 390                if (to_fetch.nr)
 391                        fetch_objects(repository_format_partial_clone,
 392                                      &to_fetch);
 393                fetch_if_missing = fetch_if_missing_store;
 394        }
 395        for (i = 0; i < index->cache_nr; i++) {
 396                struct cache_entry *ce = index->cache[i];
 397
 398                if (ce->ce_flags & CE_UPDATE) {
 399                        if (ce->ce_flags & CE_WT_REMOVE)
 400                                die("BUG: both update and delete flags are set on %s",
 401                                    ce->name);
 402                        display_progress(progress, ++cnt);
 403                        ce->ce_flags &= ~CE_UPDATE;
 404                        if (o->update && !o->dry_run) {
 405                                errs |= checkout_entry(ce, &state, NULL);
 406                        }
 407                }
 408        }
 409        stop_progress(&progress);
 410        errs |= finish_delayed_checkout(&state);
 411        if (o->update)
 412                git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
 413        return errs != 0;
 414}
 415
 416static int verify_uptodate_sparse(const struct cache_entry *ce,
 417                                  struct unpack_trees_options *o);
 418static int verify_absent_sparse(const struct cache_entry *ce,
 419                                enum unpack_trees_error_types,
 420                                struct unpack_trees_options *o);
 421
 422static int apply_sparse_checkout(struct index_state *istate,
 423                                 struct cache_entry *ce,
 424                                 struct unpack_trees_options *o)
 425{
 426        int was_skip_worktree = ce_skip_worktree(ce);
 427
 428        if (ce->ce_flags & CE_NEW_SKIP_WORKTREE)
 429                ce->ce_flags |= CE_SKIP_WORKTREE;
 430        else
 431                ce->ce_flags &= ~CE_SKIP_WORKTREE;
 432        if (was_skip_worktree != ce_skip_worktree(ce)) {
 433                ce->ce_flags |= CE_UPDATE_IN_BASE;
 434                mark_fsmonitor_invalid(istate, ce);
 435                istate->cache_changed |= CE_ENTRY_CHANGED;
 436        }
 437
 438        /*
 439         * if (!was_skip_worktree && !ce_skip_worktree()) {
 440         *      This is perfectly normal. Move on;
 441         * }
 442         */
 443
 444        /*
 445         * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
 446         * area as a result of ce_skip_worktree() shortcuts in
 447         * verify_absent() and verify_uptodate().
 448         * Make sure they don't modify worktree if they are already
 449         * outside checkout area
 450         */
 451        if (was_skip_worktree && ce_skip_worktree(ce)) {
 452                ce->ce_flags &= ~CE_UPDATE;
 453
 454                /*
 455                 * By default, when CE_REMOVE is on, CE_WT_REMOVE is also
 456                 * on to get that file removed from both index and worktree.
 457                 * If that file is already outside worktree area, don't
 458                 * bother remove it.
 459                 */
 460                if (ce->ce_flags & CE_REMOVE)
 461                        ce->ce_flags &= ~CE_WT_REMOVE;
 462        }
 463
 464        if (!was_skip_worktree && ce_skip_worktree(ce)) {
 465                /*
 466                 * If CE_UPDATE is set, verify_uptodate() must be called already
 467                 * also stat info may have lost after merged_entry() so calling
 468                 * verify_uptodate() again may fail
 469                 */
 470                if (!(ce->ce_flags & CE_UPDATE) && verify_uptodate_sparse(ce, o))
 471                        return -1;
 472                ce->ce_flags |= CE_WT_REMOVE;
 473                ce->ce_flags &= ~CE_UPDATE;
 474        }
 475        if (was_skip_worktree && !ce_skip_worktree(ce)) {
 476                if (verify_absent_sparse(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o))
 477                        return -1;
 478                ce->ce_flags |= CE_UPDATE;
 479        }
 480        return 0;
 481}
 482
 483static inline int call_unpack_fn(const struct cache_entry * const *src,
 484                                 struct unpack_trees_options *o)
 485{
 486        int ret = o->fn(src, o);
 487        if (ret > 0)
 488                ret = 0;
 489        return ret;
 490}
 491
 492static void mark_ce_used(struct cache_entry *ce, struct unpack_trees_options *o)
 493{
 494        ce->ce_flags |= CE_UNPACKED;
 495
 496        if (o->cache_bottom < o->src_index->cache_nr &&
 497            o->src_index->cache[o->cache_bottom] == ce) {
 498                int bottom = o->cache_bottom;
 499                while (bottom < o->src_index->cache_nr &&
 500                       o->src_index->cache[bottom]->ce_flags & CE_UNPACKED)
 501                        bottom++;
 502                o->cache_bottom = bottom;
 503        }
 504}
 505
 506static void mark_all_ce_unused(struct index_state *index)
 507{
 508        int i;
 509        for (i = 0; i < index->cache_nr; i++)
 510                index->cache[i]->ce_flags &= ~(CE_UNPACKED | CE_ADDED | CE_NEW_SKIP_WORKTREE);
 511}
 512
 513static int locate_in_src_index(const struct cache_entry *ce,
 514                               struct unpack_trees_options *o)
 515{
 516        struct index_state *index = o->src_index;
 517        int len = ce_namelen(ce);
 518        int pos = index_name_pos(index, ce->name, len);
 519        if (pos < 0)
 520                pos = -1 - pos;
 521        return pos;
 522}
 523
 524/*
 525 * We call unpack_index_entry() with an unmerged cache entry
 526 * only in diff-index, and it wants a single callback.  Skip
 527 * the other unmerged entry with the same name.
 528 */
 529static void mark_ce_used_same_name(struct cache_entry *ce,
 530                                   struct unpack_trees_options *o)
 531{
 532        struct index_state *index = o->src_index;
 533        int len = ce_namelen(ce);
 534        int pos;
 535
 536        for (pos = locate_in_src_index(ce, o); pos < index->cache_nr; pos++) {
 537                struct cache_entry *next = index->cache[pos];
 538                if (len != ce_namelen(next) ||
 539                    memcmp(ce->name, next->name, len))
 540                        break;
 541                mark_ce_used(next, o);
 542        }
 543}
 544
 545static struct cache_entry *next_cache_entry(struct unpack_trees_options *o)
 546{
 547        const struct index_state *index = o->src_index;
 548        int pos = o->cache_bottom;
 549
 550        while (pos < index->cache_nr) {
 551                struct cache_entry *ce = index->cache[pos];
 552                if (!(ce->ce_flags & CE_UNPACKED))
 553                        return ce;
 554                pos++;
 555        }
 556        return NULL;
 557}
 558
 559static void add_same_unmerged(const struct cache_entry *ce,
 560                              struct unpack_trees_options *o)
 561{
 562        struct index_state *index = o->src_index;
 563        int len = ce_namelen(ce);
 564        int pos = index_name_pos(index, ce->name, len);
 565
 566        if (0 <= pos)
 567                die("programming error in a caller of mark_ce_used_same_name");
 568        for (pos = -pos - 1; pos < index->cache_nr; pos++) {
 569                struct cache_entry *next = index->cache[pos];
 570                if (len != ce_namelen(next) ||
 571                    memcmp(ce->name, next->name, len))
 572                        break;
 573                add_entry(o, next, 0, 0);
 574                mark_ce_used(next, o);
 575        }
 576}
 577
 578static int unpack_index_entry(struct cache_entry *ce,
 579                              struct unpack_trees_options *o)
 580{
 581        const struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 582        int ret;
 583
 584        src[0] = ce;
 585
 586        mark_ce_used(ce, o);
 587        if (ce_stage(ce)) {
 588                if (o->skip_unmerged) {
 589                        add_entry(o, ce, 0, 0);
 590                        return 0;
 591                }
 592        }
 593        ret = call_unpack_fn(src, o);
 594        if (ce_stage(ce))
 595                mark_ce_used_same_name(ce, o);
 596        return ret;
 597}
 598
 599static int find_cache_pos(struct traverse_info *, const struct name_entry *);
 600
 601static void restore_cache_bottom(struct traverse_info *info, int bottom)
 602{
 603        struct unpack_trees_options *o = info->data;
 604
 605        if (o->diff_index_cached)
 606                return;
 607        o->cache_bottom = bottom;
 608}
 609
 610static int switch_cache_bottom(struct traverse_info *info)
 611{
 612        struct unpack_trees_options *o = info->data;
 613        int ret, pos;
 614
 615        if (o->diff_index_cached)
 616                return 0;
 617        ret = o->cache_bottom;
 618        pos = find_cache_pos(info->prev, &info->name);
 619
 620        if (pos < -1)
 621                o->cache_bottom = -2 - pos;
 622        else if (pos < 0)
 623                o->cache_bottom = o->src_index->cache_nr;
 624        return ret;
 625}
 626
 627static inline int are_same_oid(struct name_entry *name_j, struct name_entry *name_k)
 628{
 629        return name_j->oid && name_k->oid && !oidcmp(name_j->oid, name_k->oid);
 630}
 631
 632static int traverse_trees_recursive(int n, unsigned long dirmask,
 633                                    unsigned long df_conflicts,
 634                                    struct name_entry *names,
 635                                    struct traverse_info *info)
 636{
 637        int i, ret, bottom;
 638        int nr_buf = 0;
 639        struct tree_desc t[MAX_UNPACK_TREES];
 640        void *buf[MAX_UNPACK_TREES];
 641        struct traverse_info newinfo;
 642        struct name_entry *p;
 643
 644        p = names;
 645        while (!p->mode)
 646                p++;
 647
 648        newinfo = *info;
 649        newinfo.prev = info;
 650        newinfo.pathspec = info->pathspec;
 651        newinfo.name = *p;
 652        newinfo.pathlen += tree_entry_len(p) + 1;
 653        newinfo.df_conflicts |= df_conflicts;
 654
 655        /*
 656         * Fetch the tree from the ODB for each peer directory in the
 657         * n commits.
 658         *
 659         * For 2- and 3-way traversals, we try to avoid hitting the
 660         * ODB twice for the same OID.  This should yield a nice speed
 661         * up in checkouts and merges when the commits are similar.
 662         *
 663         * We don't bother doing the full O(n^2) search for larger n,
 664         * because wider traversals don't happen that often and we
 665         * avoid the search setup.
 666         *
 667         * When 2 peer OIDs are the same, we just copy the tree
 668         * descriptor data.  This implicitly borrows the buffer
 669         * data from the earlier cell.
 670         */
 671        for (i = 0; i < n; i++, dirmask >>= 1) {
 672                if (i > 0 && are_same_oid(&names[i], &names[i - 1]))
 673                        t[i] = t[i - 1];
 674                else if (i > 1 && are_same_oid(&names[i], &names[i - 2]))
 675                        t[i] = t[i - 2];
 676                else {
 677                        const struct object_id *oid = NULL;
 678                        if (dirmask & 1)
 679                                oid = names[i].oid;
 680                        buf[nr_buf++] = fill_tree_descriptor(t + i, oid);
 681                }
 682        }
 683
 684        bottom = switch_cache_bottom(&newinfo);
 685        ret = traverse_trees(n, t, &newinfo);
 686        restore_cache_bottom(&newinfo, bottom);
 687
 688        for (i = 0; i < nr_buf; i++)
 689                free(buf[i]);
 690
 691        return ret;
 692}
 693
 694/*
 695 * Compare the traverse-path to the cache entry without actually
 696 * having to generate the textual representation of the traverse
 697 * path.
 698 *
 699 * NOTE! This *only* compares up to the size of the traverse path
 700 * itself - the caller needs to do the final check for the cache
 701 * entry having more data at the end!
 702 */
 703static int do_compare_entry_piecewise(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 704{
 705        int len, pathlen, ce_len;
 706        const char *ce_name;
 707
 708        if (info->prev) {
 709                int cmp = do_compare_entry_piecewise(ce, info->prev,
 710                                                     &info->name);
 711                if (cmp)
 712                        return cmp;
 713        }
 714        pathlen = info->pathlen;
 715        ce_len = ce_namelen(ce);
 716
 717        /* If ce_len < pathlen then we must have previously hit "name == directory" entry */
 718        if (ce_len < pathlen)
 719                return -1;
 720
 721        ce_len -= pathlen;
 722        ce_name = ce->name + pathlen;
 723
 724        len = tree_entry_len(n);
 725        return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 726}
 727
 728static int do_compare_entry(const struct cache_entry *ce,
 729                            const struct traverse_info *info,
 730                            const struct name_entry *n)
 731{
 732        int len, pathlen, ce_len;
 733        const char *ce_name;
 734        int cmp;
 735
 736        /*
 737         * If we have not precomputed the traverse path, it is quicker
 738         * to avoid doing so.  But if we have precomputed it,
 739         * it is quicker to use the precomputed version.
 740         */
 741        if (!info->traverse_path)
 742                return do_compare_entry_piecewise(ce, info, n);
 743
 744        cmp = strncmp(ce->name, info->traverse_path, info->pathlen);
 745        if (cmp)
 746                return cmp;
 747
 748        pathlen = info->pathlen;
 749        ce_len = ce_namelen(ce);
 750
 751        if (ce_len < pathlen)
 752                return -1;
 753
 754        ce_len -= pathlen;
 755        ce_name = ce->name + pathlen;
 756
 757        len = tree_entry_len(n);
 758        return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 759}
 760
 761static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 762{
 763        int cmp = do_compare_entry(ce, info, n);
 764        if (cmp)
 765                return cmp;
 766
 767        /*
 768         * Even if the beginning compared identically, the ce should
 769         * compare as bigger than a directory leading up to it!
 770         */
 771        return ce_namelen(ce) > traverse_path_len(info, n);
 772}
 773
 774static int ce_in_traverse_path(const struct cache_entry *ce,
 775                               const struct traverse_info *info)
 776{
 777        if (!info->prev)
 778                return 1;
 779        if (do_compare_entry(ce, info->prev, &info->name))
 780                return 0;
 781        /*
 782         * If ce (blob) is the same name as the path (which is a tree
 783         * we will be descending into), it won't be inside it.
 784         */
 785        return (info->pathlen < ce_namelen(ce));
 786}
 787
 788static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
 789{
 790        int len = traverse_path_len(info, n);
 791        struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
 792
 793        ce->ce_mode = create_ce_mode(n->mode);
 794        ce->ce_flags = create_ce_flags(stage);
 795        ce->ce_namelen = len;
 796        oidcpy(&ce->oid, n->oid);
 797        make_traverse_path(ce->name, info, n);
 798
 799        return ce;
 800}
 801
 802static int unpack_nondirectories(int n, unsigned long mask,
 803                                 unsigned long dirmask,
 804                                 struct cache_entry **src,
 805                                 const struct name_entry *names,
 806                                 const struct traverse_info *info)
 807{
 808        int i;
 809        struct unpack_trees_options *o = info->data;
 810        unsigned long conflicts = info->df_conflicts | dirmask;
 811
 812        /* Do we have *only* directories? Nothing to do */
 813        if (mask == dirmask && !src[0])
 814                return 0;
 815
 816        /*
 817         * Ok, we've filled in up to any potential index entry in src[0],
 818         * now do the rest.
 819         */
 820        for (i = 0; i < n; i++) {
 821                int stage;
 822                unsigned int bit = 1ul << i;
 823                if (conflicts & bit) {
 824                        src[i + o->merge] = o->df_conflict_entry;
 825                        continue;
 826                }
 827                if (!(mask & bit))
 828                        continue;
 829                if (!o->merge)
 830                        stage = 0;
 831                else if (i + 1 < o->head_idx)
 832                        stage = 1;
 833                else if (i + 1 > o->head_idx)
 834                        stage = 3;
 835                else
 836                        stage = 2;
 837                src[i + o->merge] = create_ce_entry(info, names + i, stage);
 838        }
 839
 840        if (o->merge) {
 841                int rc = call_unpack_fn((const struct cache_entry * const *)src,
 842                                        o);
 843                for (i = 0; i < n; i++) {
 844                        struct cache_entry *ce = src[i + o->merge];
 845                        if (ce != o->df_conflict_entry)
 846                                free(ce);
 847                }
 848                return rc;
 849        }
 850
 851        for (i = 0; i < n; i++)
 852                if (src[i] && src[i] != o->df_conflict_entry)
 853                        if (do_add_entry(o, src[i], 0, 0))
 854                                return -1;
 855
 856        return 0;
 857}
 858
 859static int unpack_failed(struct unpack_trees_options *o, const char *message)
 860{
 861        discard_index(&o->result);
 862        if (!o->gently && !o->exiting_early) {
 863                if (message)
 864                        return error("%s", message);
 865                return -1;
 866        }
 867        return -1;
 868}
 869
 870/*
 871 * The tree traversal is looking at name p.  If we have a matching entry,
 872 * return it.  If name p is a directory in the index, do not return
 873 * anything, as we will want to match it when the traversal descends into
 874 * the directory.
 875 */
 876static int find_cache_pos(struct traverse_info *info,
 877                          const struct name_entry *p)
 878{
 879        int pos;
 880        struct unpack_trees_options *o = info->data;
 881        struct index_state *index = o->src_index;
 882        int pfxlen = info->pathlen;
 883        int p_len = tree_entry_len(p);
 884
 885        for (pos = o->cache_bottom; pos < index->cache_nr; pos++) {
 886                const struct cache_entry *ce = index->cache[pos];
 887                const char *ce_name, *ce_slash;
 888                int cmp, ce_len;
 889
 890                if (ce->ce_flags & CE_UNPACKED) {
 891                        /*
 892                         * cache_bottom entry is already unpacked, so
 893                         * we can never match it; don't check it
 894                         * again.
 895                         */
 896                        if (pos == o->cache_bottom)
 897                                ++o->cache_bottom;
 898                        continue;
 899                }
 900                if (!ce_in_traverse_path(ce, info)) {
 901                        /*
 902                         * Check if we can skip future cache checks
 903                         * (because we're already past all possible
 904                         * entries in the traverse path).
 905                         */
 906                        if (info->traverse_path) {
 907                                if (strncmp(ce->name, info->traverse_path,
 908                                            info->pathlen) > 0)
 909                                        break;
 910                        }
 911                        continue;
 912                }
 913                ce_name = ce->name + pfxlen;
 914                ce_slash = strchr(ce_name, '/');
 915                if (ce_slash)
 916                        ce_len = ce_slash - ce_name;
 917                else
 918                        ce_len = ce_namelen(ce) - pfxlen;
 919                cmp = name_compare(p->path, p_len, ce_name, ce_len);
 920                /*
 921                 * Exact match; if we have a directory we need to
 922                 * delay returning it.
 923                 */
 924                if (!cmp)
 925                        return ce_slash ? -2 - pos : pos;
 926                if (0 < cmp)
 927                        continue; /* keep looking */
 928                /*
 929                 * ce_name sorts after p->path; could it be that we
 930                 * have files under p->path directory in the index?
 931                 * E.g.  ce_name == "t-i", and p->path == "t"; we may
 932                 * have "t/a" in the index.
 933                 */
 934                if (p_len < ce_len && !memcmp(ce_name, p->path, p_len) &&
 935                    ce_name[p_len] < '/')
 936                        continue; /* keep looking */
 937                break;
 938        }
 939        return -1;
 940}
 941
 942static struct cache_entry *find_cache_entry(struct traverse_info *info,
 943                                            const struct name_entry *p)
 944{
 945        int pos = find_cache_pos(info, p);
 946        struct unpack_trees_options *o = info->data;
 947
 948        if (0 <= pos)
 949                return o->src_index->cache[pos];
 950        else
 951                return NULL;
 952}
 953
 954static void debug_path(struct traverse_info *info)
 955{
 956        if (info->prev) {
 957                debug_path(info->prev);
 958                if (*info->prev->name.path)
 959                        putchar('/');
 960        }
 961        printf("%s", info->name.path);
 962}
 963
 964static void debug_name_entry(int i, struct name_entry *n)
 965{
 966        printf("ent#%d %06o %s\n", i,
 967               n->path ? n->mode : 0,
 968               n->path ? n->path : "(missing)");
 969}
 970
 971static void debug_unpack_callback(int n,
 972                                  unsigned long mask,
 973                                  unsigned long dirmask,
 974                                  struct name_entry *names,
 975                                  struct traverse_info *info)
 976{
 977        int i;
 978        printf("* unpack mask %lu, dirmask %lu, cnt %d ",
 979               mask, dirmask, n);
 980        debug_path(info);
 981        putchar('\n');
 982        for (i = 0; i < n; i++)
 983                debug_name_entry(i, names + i);
 984}
 985
 986static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
 987{
 988        struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 989        struct unpack_trees_options *o = info->data;
 990        const struct name_entry *p = names;
 991
 992        /* Find first entry with a real name (we could use "mask" too) */
 993        while (!p->mode)
 994                p++;
 995
 996        if (o->debug_unpack)
 997                debug_unpack_callback(n, mask, dirmask, names, info);
 998
 999        /* Are we supposed to look at the index too? */
1000        if (o->merge) {
1001                while (1) {
1002                        int cmp;
1003                        struct cache_entry *ce;
1004
1005                        if (o->diff_index_cached)
1006                                ce = next_cache_entry(o);
1007                        else
1008                                ce = find_cache_entry(info, p);
1009
1010                        if (!ce)
1011                                break;
1012                        cmp = compare_entry(ce, info, p);
1013                        if (cmp < 0) {
1014                                if (unpack_index_entry(ce, o) < 0)
1015                                        return unpack_failed(o, NULL);
1016                                continue;
1017                        }
1018                        if (!cmp) {
1019                                if (ce_stage(ce)) {
1020                                        /*
1021                                         * If we skip unmerged index
1022                                         * entries, we'll skip this
1023                                         * entry *and* the tree
1024                                         * entries associated with it!
1025                                         */
1026                                        if (o->skip_unmerged) {
1027                                                add_same_unmerged(ce, o);
1028                                                return mask;
1029                                        }
1030                                }
1031                                src[0] = ce;
1032                        }
1033                        break;
1034                }
1035        }
1036
1037        if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
1038                return -1;
1039
1040        if (o->merge && src[0]) {
1041                if (ce_stage(src[0]))
1042                        mark_ce_used_same_name(src[0], o);
1043                else
1044                        mark_ce_used(src[0], o);
1045        }
1046
1047        /* Now handle any directories.. */
1048        if (dirmask) {
1049                /* special case: "diff-index --cached" looking at a tree */
1050                if (o->diff_index_cached &&
1051                    n == 1 && dirmask == 1 && S_ISDIR(names->mode)) {
1052                        int matches;
1053                        matches = cache_tree_matches_traversal(o->src_index->cache_tree,
1054                                                               names, info);
1055                        /*
1056                         * Everything under the name matches; skip the
1057                         * entire hierarchy.  diff_index_cached codepath
1058                         * special cases D/F conflicts in such a way that
1059                         * it does not do any look-ahead, so this is safe.
1060                         */
1061                        if (matches) {
1062                                o->cache_bottom += matches;
1063                                return mask;
1064                        }
1065                }
1066
1067                if (traverse_trees_recursive(n, dirmask, mask & ~dirmask,
1068                                             names, info) < 0)
1069                        return -1;
1070                return mask;
1071        }
1072
1073        return mask;
1074}
1075
1076static int clear_ce_flags_1(struct cache_entry **cache, int nr,
1077                            struct strbuf *prefix,
1078                            int select_mask, int clear_mask,
1079                            struct exclude_list *el, int defval);
1080
1081/* Whole directory matching */
1082static int clear_ce_flags_dir(struct cache_entry **cache, int nr,
1083                              struct strbuf *prefix,
1084                              char *basename,
1085                              int select_mask, int clear_mask,
1086                              struct exclude_list *el, int defval)
1087{
1088        struct cache_entry **cache_end;
1089        int dtype = DT_DIR;
1090        int ret = is_excluded_from_list(prefix->buf, prefix->len,
1091                                        basename, &dtype, el, &the_index);
1092        int rc;
1093
1094        strbuf_addch(prefix, '/');
1095
1096        /* If undecided, use matching result of parent dir in defval */
1097        if (ret < 0)
1098                ret = defval;
1099
1100        for (cache_end = cache; cache_end != cache + nr; cache_end++) {
1101                struct cache_entry *ce = *cache_end;
1102                if (strncmp(ce->name, prefix->buf, prefix->len))
1103                        break;
1104        }
1105
1106        /*
1107         * TODO: check el, if there are no patterns that may conflict
1108         * with ret (iow, we know in advance the incl/excl
1109         * decision for the entire directory), clear flag here without
1110         * calling clear_ce_flags_1(). That function will call
1111         * the expensive is_excluded_from_list() on every entry.
1112         */
1113        rc = clear_ce_flags_1(cache, cache_end - cache,
1114                              prefix,
1115                              select_mask, clear_mask,
1116                              el, ret);
1117        strbuf_setlen(prefix, prefix->len - 1);
1118        return rc;
1119}
1120
1121/*
1122 * Traverse the index, find every entry that matches according to
1123 * o->el. Do "ce_flags &= ~clear_mask" on those entries. Return the
1124 * number of traversed entries.
1125 *
1126 * If select_mask is non-zero, only entries whose ce_flags has on of
1127 * those bits enabled are traversed.
1128 *
1129 * cache        : pointer to an index entry
1130 * prefix_len   : an offset to its path
1131 *
1132 * The current path ("prefix") including the trailing '/' is
1133 *   cache[0]->name[0..(prefix_len-1)]
1134 * Top level path has prefix_len zero.
1135 */
1136static int clear_ce_flags_1(struct cache_entry **cache, int nr,
1137                            struct strbuf *prefix,
1138                            int select_mask, int clear_mask,
1139                            struct exclude_list *el, int defval)
1140{
1141        struct cache_entry **cache_end = cache + nr;
1142
1143        /*
1144         * Process all entries that have the given prefix and meet
1145         * select_mask condition
1146         */
1147        while(cache != cache_end) {
1148                struct cache_entry *ce = *cache;
1149                const char *name, *slash;
1150                int len, dtype, ret;
1151
1152                if (select_mask && !(ce->ce_flags & select_mask)) {
1153                        cache++;
1154                        continue;
1155                }
1156
1157                if (prefix->len && strncmp(ce->name, prefix->buf, prefix->len))
1158                        break;
1159
1160                name = ce->name + prefix->len;
1161                slash = strchr(name, '/');
1162
1163                /* If it's a directory, try whole directory match first */
1164                if (slash) {
1165                        int processed;
1166
1167                        len = slash - name;
1168                        strbuf_add(prefix, name, len);
1169
1170                        processed = clear_ce_flags_dir(cache, cache_end - cache,
1171                                                       prefix,
1172                                                       prefix->buf + prefix->len - len,
1173                                                       select_mask, clear_mask,
1174                                                       el, defval);
1175
1176                        /* clear_c_f_dir eats a whole dir already? */
1177                        if (processed) {
1178                                cache += processed;
1179                                strbuf_setlen(prefix, prefix->len - len);
1180                                continue;
1181                        }
1182
1183                        strbuf_addch(prefix, '/');
1184                        cache += clear_ce_flags_1(cache, cache_end - cache,
1185                                                  prefix,
1186                                                  select_mask, clear_mask, el, defval);
1187                        strbuf_setlen(prefix, prefix->len - len - 1);
1188                        continue;
1189                }
1190
1191                /* Non-directory */
1192                dtype = ce_to_dtype(ce);
1193                ret = is_excluded_from_list(ce->name, ce_namelen(ce),
1194                                            name, &dtype, el, &the_index);
1195                if (ret < 0)
1196                        ret = defval;
1197                if (ret > 0)
1198                        ce->ce_flags &= ~clear_mask;
1199                cache++;
1200        }
1201        return nr - (cache_end - cache);
1202}
1203
1204static int clear_ce_flags(struct cache_entry **cache, int nr,
1205                            int select_mask, int clear_mask,
1206                            struct exclude_list *el)
1207{
1208        static struct strbuf prefix = STRBUF_INIT;
1209
1210        strbuf_reset(&prefix);
1211
1212        return clear_ce_flags_1(cache, nr,
1213                                &prefix,
1214                                select_mask, clear_mask,
1215                                el, 0);
1216}
1217
1218/*
1219 * Set/Clear CE_NEW_SKIP_WORKTREE according to $GIT_DIR/info/sparse-checkout
1220 */
1221static void mark_new_skip_worktree(struct exclude_list *el,
1222                                   struct index_state *the_index,
1223                                   int select_flag, int skip_wt_flag)
1224{
1225        int i;
1226
1227        /*
1228         * 1. Pretend the narrowest worktree: only unmerged entries
1229         * are checked out
1230         */
1231        for (i = 0; i < the_index->cache_nr; i++) {
1232                struct cache_entry *ce = the_index->cache[i];
1233
1234                if (select_flag && !(ce->ce_flags & select_flag))
1235                        continue;
1236
1237                if (!ce_stage(ce))
1238                        ce->ce_flags |= skip_wt_flag;
1239                else
1240                        ce->ce_flags &= ~skip_wt_flag;
1241        }
1242
1243        /*
1244         * 2. Widen worktree according to sparse-checkout file.
1245         * Matched entries will have skip_wt_flag cleared (i.e. "in")
1246         */
1247        clear_ce_flags(the_index->cache, the_index->cache_nr,
1248                       select_flag, skip_wt_flag, el);
1249}
1250
1251static int verify_absent(const struct cache_entry *,
1252                         enum unpack_trees_error_types,
1253                         struct unpack_trees_options *);
1254/*
1255 * N-way merge "len" trees.  Returns 0 on success, -1 on failure to manipulate the
1256 * resulting index, -2 on failure to reflect the changes to the work tree.
1257 *
1258 * CE_ADDED, CE_UNPACKED and CE_NEW_SKIP_WORKTREE are used internally
1259 */
1260int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
1261{
1262        int i, ret;
1263        static struct cache_entry *dfc;
1264        struct exclude_list el;
1265
1266        if (len > MAX_UNPACK_TREES)
1267                die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
1268
1269        memset(&el, 0, sizeof(el));
1270        if (!core_apply_sparse_checkout || !o->update)
1271                o->skip_sparse_checkout = 1;
1272        if (!o->skip_sparse_checkout) {
1273                char *sparse = git_pathdup("info/sparse-checkout");
1274                if (add_excludes_from_file_to_list(sparse, "", 0, &el, NULL) < 0)
1275                        o->skip_sparse_checkout = 1;
1276                else
1277                        o->el = &el;
1278                free(sparse);
1279        }
1280
1281        memset(&o->result, 0, sizeof(o->result));
1282        o->result.initialized = 1;
1283        o->result.timestamp.sec = o->src_index->timestamp.sec;
1284        o->result.timestamp.nsec = o->src_index->timestamp.nsec;
1285        o->result.version = o->src_index->version;
1286        o->result.split_index = o->src_index->split_index;
1287        if (o->result.split_index)
1288                o->result.split_index->refcount++;
1289        hashcpy(o->result.sha1, o->src_index->sha1);
1290        o->merge_size = len;
1291        mark_all_ce_unused(o->src_index);
1292
1293        /*
1294         * Sparse checkout loop #1: set NEW_SKIP_WORKTREE on existing entries
1295         */
1296        if (!o->skip_sparse_checkout)
1297                mark_new_skip_worktree(o->el, o->src_index, 0, CE_NEW_SKIP_WORKTREE);
1298
1299        if (!dfc)
1300                dfc = xcalloc(1, cache_entry_size(0));
1301        o->df_conflict_entry = dfc;
1302
1303        if (len) {
1304                const char *prefix = o->prefix ? o->prefix : "";
1305                struct traverse_info info;
1306
1307                setup_traverse_info(&info, prefix);
1308                info.fn = unpack_callback;
1309                info.data = o;
1310                info.show_all_errors = o->show_all_errors;
1311                info.pathspec = o->pathspec;
1312
1313                if (o->prefix) {
1314                        /*
1315                         * Unpack existing index entries that sort before the
1316                         * prefix the tree is spliced into.  Note that o->merge
1317                         * is always true in this case.
1318                         */
1319                        while (1) {
1320                                struct cache_entry *ce = next_cache_entry(o);
1321                                if (!ce)
1322                                        break;
1323                                if (ce_in_traverse_path(ce, &info))
1324                                        break;
1325                                if (unpack_index_entry(ce, o) < 0)
1326                                        goto return_failed;
1327                        }
1328                }
1329
1330                if (traverse_trees(len, t, &info) < 0)
1331                        goto return_failed;
1332        }
1333
1334        /* Any left-over entries in the index? */
1335        if (o->merge) {
1336                while (1) {
1337                        struct cache_entry *ce = next_cache_entry(o);
1338                        if (!ce)
1339                                break;
1340                        if (unpack_index_entry(ce, o) < 0)
1341                                goto return_failed;
1342                }
1343        }
1344        mark_all_ce_unused(o->src_index);
1345
1346        if (o->trivial_merges_only && o->nontrivial_merge) {
1347                ret = unpack_failed(o, "Merge requires file-level merging");
1348                goto done;
1349        }
1350
1351        if (!o->skip_sparse_checkout) {
1352                int empty_worktree = 1;
1353
1354                /*
1355                 * Sparse checkout loop #2: set NEW_SKIP_WORKTREE on entries not in loop #1
1356                 * If the will have NEW_SKIP_WORKTREE, also set CE_SKIP_WORKTREE
1357                 * so apply_sparse_checkout() won't attempt to remove it from worktree
1358                 */
1359                mark_new_skip_worktree(o->el, &o->result, CE_ADDED, CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1360
1361                ret = 0;
1362                for (i = 0; i < o->result.cache_nr; i++) {
1363                        struct cache_entry *ce = o->result.cache[i];
1364
1365                        /*
1366                         * Entries marked with CE_ADDED in merged_entry() do not have
1367                         * verify_absent() check (the check is effectively disabled
1368                         * because CE_NEW_SKIP_WORKTREE is set unconditionally).
1369                         *
1370                         * Do the real check now because we have had
1371                         * correct CE_NEW_SKIP_WORKTREE
1372                         */
1373                        if (ce->ce_flags & CE_ADDED &&
1374                            verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1375                                if (!o->show_all_errors)
1376                                        goto return_failed;
1377                                ret = -1;
1378                        }
1379
1380                        if (apply_sparse_checkout(&o->result, ce, o)) {
1381                                if (!o->show_all_errors)
1382                                        goto return_failed;
1383                                ret = -1;
1384                        }
1385                        if (!ce_skip_worktree(ce))
1386                                empty_worktree = 0;
1387
1388                }
1389                if (ret < 0)
1390                        goto return_failed;
1391                /*
1392                 * Sparse checkout is meant to narrow down checkout area
1393                 * but it does not make sense to narrow down to empty working
1394                 * tree. This is usually a mistake in sparse checkout rules.
1395                 * Do not allow users to do that.
1396                 */
1397                if (o->result.cache_nr && empty_worktree) {
1398                        ret = unpack_failed(o, "Sparse checkout leaves no entry on working directory");
1399                        goto done;
1400                }
1401        }
1402
1403        o->src_index = NULL;
1404        ret = check_updates(o) ? (-2) : 0;
1405        if (o->dst_index) {
1406                if (!ret) {
1407                        if (!o->result.cache_tree)
1408                                o->result.cache_tree = cache_tree();
1409                        if (!cache_tree_fully_valid(o->result.cache_tree))
1410                                cache_tree_update(&o->result,
1411                                                  WRITE_TREE_SILENT |
1412                                                  WRITE_TREE_REPAIR);
1413                }
1414                move_index_extensions(&o->result, o->dst_index);
1415                discard_index(o->dst_index);
1416                *o->dst_index = o->result;
1417        } else {
1418                discard_index(&o->result);
1419        }
1420
1421done:
1422        clear_exclude_list(&el);
1423        return ret;
1424
1425return_failed:
1426        if (o->show_all_errors)
1427                display_error_msgs(o);
1428        mark_all_ce_unused(o->src_index);
1429        ret = unpack_failed(o, NULL);
1430        if (o->exiting_early)
1431                ret = 0;
1432        goto done;
1433}
1434
1435/* Here come the merge functions */
1436
1437static int reject_merge(const struct cache_entry *ce,
1438                        struct unpack_trees_options *o)
1439{
1440        return o->gently ? -1 :
1441                add_rejected_path(o, ERROR_WOULD_OVERWRITE, ce->name);
1442}
1443
1444static int same(const struct cache_entry *a, const struct cache_entry *b)
1445{
1446        if (!!a != !!b)
1447                return 0;
1448        if (!a && !b)
1449                return 1;
1450        if ((a->ce_flags | b->ce_flags) & CE_CONFLICTED)
1451                return 0;
1452        return a->ce_mode == b->ce_mode &&
1453               !oidcmp(&a->oid, &b->oid);
1454}
1455
1456
1457/*
1458 * When a CE gets turned into an unmerged entry, we
1459 * want it to be up-to-date
1460 */
1461static int verify_uptodate_1(const struct cache_entry *ce,
1462                             struct unpack_trees_options *o,
1463                             enum unpack_trees_error_types error_type)
1464{
1465        struct stat st;
1466
1467        if (o->index_only)
1468                return 0;
1469
1470        /*
1471         * CE_VALID and CE_SKIP_WORKTREE cheat, we better check again
1472         * if this entry is truly up-to-date because this file may be
1473         * overwritten.
1474         */
1475        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
1476                ; /* keep checking */
1477        else if (o->reset || ce_uptodate(ce))
1478                return 0;
1479
1480        if (!lstat(ce->name, &st)) {
1481                int flags = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE;
1482                unsigned changed = ie_match_stat(o->src_index, ce, &st, flags);
1483
1484                if (submodule_from_ce(ce)) {
1485                        int r = check_submodule_move_head(ce,
1486                                "HEAD", oid_to_hex(&ce->oid), o);
1487                        if (r)
1488                                return o->gently ? -1 :
1489                                        add_rejected_path(o, error_type, ce->name);
1490                        return 0;
1491                }
1492
1493                if (!changed)
1494                        return 0;
1495                /*
1496                 * Historic default policy was to allow submodule to be out
1497                 * of sync wrt the superproject index. If the submodule was
1498                 * not considered interesting above, we don't care here.
1499                 */
1500                if (S_ISGITLINK(ce->ce_mode))
1501                        return 0;
1502
1503                errno = 0;
1504        }
1505        if (errno == ENOENT)
1506                return 0;
1507        return o->gently ? -1 :
1508                add_rejected_path(o, error_type, ce->name);
1509}
1510
1511static int verify_uptodate(const struct cache_entry *ce,
1512                           struct unpack_trees_options *o)
1513{
1514        if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1515                return 0;
1516        return verify_uptodate_1(ce, o, ERROR_NOT_UPTODATE_FILE);
1517}
1518
1519static int verify_uptodate_sparse(const struct cache_entry *ce,
1520                                  struct unpack_trees_options *o)
1521{
1522        return verify_uptodate_1(ce, o, ERROR_SPARSE_NOT_UPTODATE_FILE);
1523}
1524
1525static void invalidate_ce_path(const struct cache_entry *ce,
1526                               struct unpack_trees_options *o)
1527{
1528        if (!ce)
1529                return;
1530        cache_tree_invalidate_path(o->src_index, ce->name);
1531        untracked_cache_invalidate_path(o->src_index, ce->name, 1);
1532}
1533
1534/*
1535 * Check that checking out ce->sha1 in subdir ce->name is not
1536 * going to overwrite any working files.
1537 *
1538 * Currently, git does not checkout subprojects during a superproject
1539 * checkout, so it is not going to overwrite anything.
1540 */
1541static int verify_clean_submodule(const char *old_sha1,
1542                                  const struct cache_entry *ce,
1543                                  enum unpack_trees_error_types error_type,
1544                                  struct unpack_trees_options *o)
1545{
1546        if (!submodule_from_ce(ce))
1547                return 0;
1548
1549        return check_submodule_move_head(ce, old_sha1,
1550                                         oid_to_hex(&ce->oid), o);
1551}
1552
1553static int verify_clean_subdirectory(const struct cache_entry *ce,
1554                                     enum unpack_trees_error_types error_type,
1555                                     struct unpack_trees_options *o)
1556{
1557        /*
1558         * we are about to extract "ce->name"; we would not want to lose
1559         * anything in the existing directory there.
1560         */
1561        int namelen;
1562        int i;
1563        struct dir_struct d;
1564        char *pathbuf;
1565        int cnt = 0;
1566
1567        if (S_ISGITLINK(ce->ce_mode)) {
1568                struct object_id oid;
1569                int sub_head = resolve_gitlink_ref(ce->name, "HEAD", &oid);
1570                /*
1571                 * If we are not going to update the submodule, then
1572                 * we don't care.
1573                 */
1574                if (!sub_head && !oidcmp(&oid, &ce->oid))
1575                        return 0;
1576                return verify_clean_submodule(sub_head ? NULL : oid_to_hex(&oid),
1577                                              ce, error_type, o);
1578        }
1579
1580        /*
1581         * First let's make sure we do not have a local modification
1582         * in that directory.
1583         */
1584        namelen = ce_namelen(ce);
1585        for (i = locate_in_src_index(ce, o);
1586             i < o->src_index->cache_nr;
1587             i++) {
1588                struct cache_entry *ce2 = o->src_index->cache[i];
1589                int len = ce_namelen(ce2);
1590                if (len < namelen ||
1591                    strncmp(ce->name, ce2->name, namelen) ||
1592                    ce2->name[namelen] != '/')
1593                        break;
1594                /*
1595                 * ce2->name is an entry in the subdirectory to be
1596                 * removed.
1597                 */
1598                if (!ce_stage(ce2)) {
1599                        if (verify_uptodate(ce2, o))
1600                                return -1;
1601                        add_entry(o, ce2, CE_REMOVE, 0);
1602                        mark_ce_used(ce2, o);
1603                }
1604                cnt++;
1605        }
1606
1607        /*
1608         * Then we need to make sure that we do not lose a locally
1609         * present file that is not ignored.
1610         */
1611        pathbuf = xstrfmt("%.*s/", namelen, ce->name);
1612
1613        memset(&d, 0, sizeof(d));
1614        if (o->dir)
1615                d.exclude_per_dir = o->dir->exclude_per_dir;
1616        i = read_directory(&d, &the_index, pathbuf, namelen+1, NULL);
1617        if (i)
1618                return o->gently ? -1 :
1619                        add_rejected_path(o, ERROR_NOT_UPTODATE_DIR, ce->name);
1620        free(pathbuf);
1621        return cnt;
1622}
1623
1624/*
1625 * This gets called when there was no index entry for the tree entry 'dst',
1626 * but we found a file in the working tree that 'lstat()' said was fine,
1627 * and we're on a case-insensitive filesystem.
1628 *
1629 * See if we can find a case-insensitive match in the index that also
1630 * matches the stat information, and assume it's that other file!
1631 */
1632static int icase_exists(struct unpack_trees_options *o, const char *name, int len, struct stat *st)
1633{
1634        const struct cache_entry *src;
1635
1636        src = index_file_exists(o->src_index, name, len, 1);
1637        return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
1638}
1639
1640static int check_ok_to_remove(const char *name, int len, int dtype,
1641                              const struct cache_entry *ce, struct stat *st,
1642                              enum unpack_trees_error_types error_type,
1643                              struct unpack_trees_options *o)
1644{
1645        const struct cache_entry *result;
1646
1647        /*
1648         * It may be that the 'lstat()' succeeded even though
1649         * target 'ce' was absent, because there is an old
1650         * entry that is different only in case..
1651         *
1652         * Ignore that lstat() if it matches.
1653         */
1654        if (ignore_case && icase_exists(o, name, len, st))
1655                return 0;
1656
1657        if (o->dir &&
1658            is_excluded(o->dir, &the_index, name, &dtype))
1659                /*
1660                 * ce->name is explicitly excluded, so it is Ok to
1661                 * overwrite it.
1662                 */
1663                return 0;
1664        if (S_ISDIR(st->st_mode)) {
1665                /*
1666                 * We are checking out path "foo" and
1667                 * found "foo/." in the working tree.
1668                 * This is tricky -- if we have modified
1669                 * files that are in "foo/" we would lose
1670                 * them.
1671                 */
1672                if (verify_clean_subdirectory(ce, error_type, o) < 0)
1673                        return -1;
1674                return 0;
1675        }
1676
1677        /*
1678         * The previous round may already have decided to
1679         * delete this path, which is in a subdirectory that
1680         * is being replaced with a blob.
1681         */
1682        result = index_file_exists(&o->result, name, len, 0);
1683        if (result) {
1684                if (result->ce_flags & CE_REMOVE)
1685                        return 0;
1686        }
1687
1688        return o->gently ? -1 :
1689                add_rejected_path(o, error_type, name);
1690}
1691
1692/*
1693 * We do not want to remove or overwrite a working tree file that
1694 * is not tracked, unless it is ignored.
1695 */
1696static int verify_absent_1(const struct cache_entry *ce,
1697                           enum unpack_trees_error_types error_type,
1698                           struct unpack_trees_options *o)
1699{
1700        int len;
1701        struct stat st;
1702
1703        if (o->index_only || o->reset || !o->update)
1704                return 0;
1705
1706        len = check_leading_path(ce->name, ce_namelen(ce));
1707        if (!len)
1708                return 0;
1709        else if (len > 0) {
1710                char *path;
1711                int ret;
1712
1713                path = xmemdupz(ce->name, len);
1714                if (lstat(path, &st))
1715                        ret = error_errno("cannot stat '%s'", path);
1716                else {
1717                        if (submodule_from_ce(ce))
1718                                ret = check_submodule_move_head(ce,
1719                                                                oid_to_hex(&ce->oid),
1720                                                                NULL, o);
1721                        else
1722                                ret = check_ok_to_remove(path, len, DT_UNKNOWN, NULL,
1723                                                         &st, error_type, o);
1724                }
1725                free(path);
1726                return ret;
1727        } else if (lstat(ce->name, &st)) {
1728                if (errno != ENOENT)
1729                        return error_errno("cannot stat '%s'", ce->name);
1730                return 0;
1731        } else {
1732                if (submodule_from_ce(ce))
1733                        return check_submodule_move_head(ce, oid_to_hex(&ce->oid),
1734                                                         NULL, o);
1735
1736                return check_ok_to_remove(ce->name, ce_namelen(ce),
1737                                          ce_to_dtype(ce), ce, &st,
1738                                          error_type, o);
1739        }
1740}
1741
1742static int verify_absent(const struct cache_entry *ce,
1743                         enum unpack_trees_error_types error_type,
1744                         struct unpack_trees_options *o)
1745{
1746        if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1747                return 0;
1748        return verify_absent_1(ce, error_type, o);
1749}
1750
1751static int verify_absent_sparse(const struct cache_entry *ce,
1752                                enum unpack_trees_error_types error_type,
1753                                struct unpack_trees_options *o)
1754{
1755        enum unpack_trees_error_types orphaned_error = error_type;
1756        if (orphaned_error == ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN)
1757                orphaned_error = ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN;
1758
1759        return verify_absent_1(ce, orphaned_error, o);
1760}
1761
1762static int merged_entry(const struct cache_entry *ce,
1763                        const struct cache_entry *old,
1764                        struct unpack_trees_options *o)
1765{
1766        int update = CE_UPDATE;
1767        struct cache_entry *merge = dup_entry(ce);
1768
1769        if (!old) {
1770                /*
1771                 * New index entries. In sparse checkout, the following
1772                 * verify_absent() will be delayed until after
1773                 * traverse_trees() finishes in unpack_trees(), then:
1774                 *
1775                 *  - CE_NEW_SKIP_WORKTREE will be computed correctly
1776                 *  - verify_absent() be called again, this time with
1777                 *    correct CE_NEW_SKIP_WORKTREE
1778                 *
1779                 * verify_absent() call here does nothing in sparse
1780                 * checkout (i.e. o->skip_sparse_checkout == 0)
1781                 */
1782                update |= CE_ADDED;
1783                merge->ce_flags |= CE_NEW_SKIP_WORKTREE;
1784
1785                if (verify_absent(merge,
1786                                  ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1787                        free(merge);
1788                        return -1;
1789                }
1790                invalidate_ce_path(merge, o);
1791
1792                if (submodule_from_ce(ce)) {
1793                        int ret = check_submodule_move_head(ce, NULL,
1794                                                            oid_to_hex(&ce->oid),
1795                                                            o);
1796                        if (ret)
1797                                return ret;
1798                }
1799
1800        } else if (!(old->ce_flags & CE_CONFLICTED)) {
1801                /*
1802                 * See if we can re-use the old CE directly?
1803                 * That way we get the uptodate stat info.
1804                 *
1805                 * This also removes the UPDATE flag on a match; otherwise
1806                 * we will end up overwriting local changes in the work tree.
1807                 */
1808                if (same(old, merge)) {
1809                        copy_cache_entry(merge, old);
1810                        update = 0;
1811                } else {
1812                        if (verify_uptodate(old, o)) {
1813                                free(merge);
1814                                return -1;
1815                        }
1816                        /* Migrate old flags over */
1817                        update |= old->ce_flags & (CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1818                        invalidate_ce_path(old, o);
1819                }
1820
1821                if (submodule_from_ce(ce)) {
1822                        int ret = check_submodule_move_head(ce, oid_to_hex(&old->oid),
1823                                                            oid_to_hex(&ce->oid),
1824                                                            o);
1825                        if (ret)
1826                                return ret;
1827                }
1828        } else {
1829                /*
1830                 * Previously unmerged entry left as an existence
1831                 * marker by read_index_unmerged();
1832                 */
1833                invalidate_ce_path(old, o);
1834        }
1835
1836        do_add_entry(o, merge, update, CE_STAGEMASK);
1837        return 1;
1838}
1839
1840static int deleted_entry(const struct cache_entry *ce,
1841                         const struct cache_entry *old,
1842                         struct unpack_trees_options *o)
1843{
1844        /* Did it exist in the index? */
1845        if (!old) {
1846                if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1847                        return -1;
1848                return 0;
1849        }
1850        if (!(old->ce_flags & CE_CONFLICTED) && verify_uptodate(old, o))
1851                return -1;
1852        add_entry(o, ce, CE_REMOVE, 0);
1853        invalidate_ce_path(ce, o);
1854        return 1;
1855}
1856
1857static int keep_entry(const struct cache_entry *ce,
1858                      struct unpack_trees_options *o)
1859{
1860        add_entry(o, ce, 0, 0);
1861        return 1;
1862}
1863
1864#if DBRT_DEBUG
1865static void show_stage_entry(FILE *o,
1866                             const char *label, const struct cache_entry *ce)
1867{
1868        if (!ce)
1869                fprintf(o, "%s (missing)\n", label);
1870        else
1871                fprintf(o, "%s%06o %s %d\t%s\n",
1872                        label,
1873                        ce->ce_mode,
1874                        oid_to_hex(&ce->oid),
1875                        ce_stage(ce),
1876                        ce->name);
1877}
1878#endif
1879
1880int threeway_merge(const struct cache_entry * const *stages,
1881                   struct unpack_trees_options *o)
1882{
1883        const struct cache_entry *index;
1884        const struct cache_entry *head;
1885        const struct cache_entry *remote = stages[o->head_idx + 1];
1886        int count;
1887        int head_match = 0;
1888        int remote_match = 0;
1889
1890        int df_conflict_head = 0;
1891        int df_conflict_remote = 0;
1892
1893        int any_anc_missing = 0;
1894        int no_anc_exists = 1;
1895        int i;
1896
1897        for (i = 1; i < o->head_idx; i++) {
1898                if (!stages[i] || stages[i] == o->df_conflict_entry)
1899                        any_anc_missing = 1;
1900                else
1901                        no_anc_exists = 0;
1902        }
1903
1904        index = stages[0];
1905        head = stages[o->head_idx];
1906
1907        if (head == o->df_conflict_entry) {
1908                df_conflict_head = 1;
1909                head = NULL;
1910        }
1911
1912        if (remote == o->df_conflict_entry) {
1913                df_conflict_remote = 1;
1914                remote = NULL;
1915        }
1916
1917        /*
1918         * First, if there's a #16 situation, note that to prevent #13
1919         * and #14.
1920         */
1921        if (!same(remote, head)) {
1922                for (i = 1; i < o->head_idx; i++) {
1923                        if (same(stages[i], head)) {
1924                                head_match = i;
1925                        }
1926                        if (same(stages[i], remote)) {
1927                                remote_match = i;
1928                        }
1929                }
1930        }
1931
1932        /*
1933         * We start with cases where the index is allowed to match
1934         * something other than the head: #14(ALT) and #2ALT, where it
1935         * is permitted to match the result instead.
1936         */
1937        /* #14, #14ALT, #2ALT */
1938        if (remote && !df_conflict_head && head_match && !remote_match) {
1939                if (index && !same(index, remote) && !same(index, head))
1940                        return reject_merge(index, o);
1941                return merged_entry(remote, index, o);
1942        }
1943        /*
1944         * If we have an entry in the index cache, then we want to
1945         * make sure that it matches head.
1946         */
1947        if (index && !same(index, head))
1948                return reject_merge(index, o);
1949
1950        if (head) {
1951                /* #5ALT, #15 */
1952                if (same(head, remote))
1953                        return merged_entry(head, index, o);
1954                /* #13, #3ALT */
1955                if (!df_conflict_remote && remote_match && !head_match)
1956                        return merged_entry(head, index, o);
1957        }
1958
1959        /* #1 */
1960        if (!head && !remote && any_anc_missing)
1961                return 0;
1962
1963        /*
1964         * Under the "aggressive" rule, we resolve mostly trivial
1965         * cases that we historically had git-merge-one-file resolve.
1966         */
1967        if (o->aggressive) {
1968                int head_deleted = !head;
1969                int remote_deleted = !remote;
1970                const struct cache_entry *ce = NULL;
1971
1972                if (index)
1973                        ce = index;
1974                else if (head)
1975                        ce = head;
1976                else if (remote)
1977                        ce = remote;
1978                else {
1979                        for (i = 1; i < o->head_idx; i++) {
1980                                if (stages[i] && stages[i] != o->df_conflict_entry) {
1981                                        ce = stages[i];
1982                                        break;
1983                                }
1984                        }
1985                }
1986
1987                /*
1988                 * Deleted in both.
1989                 * Deleted in one and unchanged in the other.
1990                 */
1991                if ((head_deleted && remote_deleted) ||
1992                    (head_deleted && remote && remote_match) ||
1993                    (remote_deleted && head && head_match)) {
1994                        if (index)
1995                                return deleted_entry(index, index, o);
1996                        if (ce && !head_deleted) {
1997                                if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1998                                        return -1;
1999                        }
2000                        return 0;
2001                }
2002                /*
2003                 * Added in both, identically.
2004                 */
2005                if (no_anc_exists && head && remote && same(head, remote))
2006                        return merged_entry(head, index, o);
2007
2008        }
2009
2010        /* Below are "no merge" cases, which require that the index be
2011         * up-to-date to avoid the files getting overwritten with
2012         * conflict resolution files.
2013         */
2014        if (index) {
2015                if (verify_uptodate(index, o))
2016                        return -1;
2017        }
2018
2019        o->nontrivial_merge = 1;
2020
2021        /* #2, #3, #4, #6, #7, #9, #10, #11. */
2022        count = 0;
2023        if (!head_match || !remote_match) {
2024                for (i = 1; i < o->head_idx; i++) {
2025                        if (stages[i] && stages[i] != o->df_conflict_entry) {
2026                                keep_entry(stages[i], o);
2027                                count++;
2028                                break;
2029                        }
2030                }
2031        }
2032#if DBRT_DEBUG
2033        else {
2034                fprintf(stderr, "read-tree: warning #16 detected\n");
2035                show_stage_entry(stderr, "head   ", stages[head_match]);
2036                show_stage_entry(stderr, "remote ", stages[remote_match]);
2037        }
2038#endif
2039        if (head) { count += keep_entry(head, o); }
2040        if (remote) { count += keep_entry(remote, o); }
2041        return count;
2042}
2043
2044/*
2045 * Two-way merge.
2046 *
2047 * The rule is to "carry forward" what is in the index without losing
2048 * information across a "fast-forward", favoring a successful merge
2049 * over a merge failure when it makes sense.  For details of the
2050 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
2051 *
2052 */
2053int twoway_merge(const struct cache_entry * const *src,
2054                 struct unpack_trees_options *o)
2055{
2056        const struct cache_entry *current = src[0];
2057        const struct cache_entry *oldtree = src[1];
2058        const struct cache_entry *newtree = src[2];
2059
2060        if (o->merge_size != 2)
2061                return error("Cannot do a twoway merge of %d trees",
2062                             o->merge_size);
2063
2064        if (oldtree == o->df_conflict_entry)
2065                oldtree = NULL;
2066        if (newtree == o->df_conflict_entry)
2067                newtree = NULL;
2068
2069        if (current) {
2070                if (current->ce_flags & CE_CONFLICTED) {
2071                        if (same(oldtree, newtree) || o->reset) {
2072                                if (!newtree)
2073                                        return deleted_entry(current, current, o);
2074                                else
2075                                        return merged_entry(newtree, current, o);
2076                        }
2077                        return reject_merge(current, o);
2078                } else if ((!oldtree && !newtree) || /* 4 and 5 */
2079                         (!oldtree && newtree &&
2080                          same(current, newtree)) || /* 6 and 7 */
2081                         (oldtree && newtree &&
2082                          same(oldtree, newtree)) || /* 14 and 15 */
2083                         (oldtree && newtree &&
2084                          !same(oldtree, newtree) && /* 18 and 19 */
2085                          same(current, newtree))) {
2086                        return keep_entry(current, o);
2087                } else if (oldtree && !newtree && same(current, oldtree)) {
2088                        /* 10 or 11 */
2089                        return deleted_entry(oldtree, current, o);
2090                } else if (oldtree && newtree &&
2091                         same(current, oldtree) && !same(current, newtree)) {
2092                        /* 20 or 21 */
2093                        return merged_entry(newtree, current, o);
2094                } else
2095                        return reject_merge(current, o);
2096        }
2097        else if (newtree) {
2098                if (oldtree && !o->initial_checkout) {
2099                        /*
2100                         * deletion of the path was staged;
2101                         */
2102                        if (same(oldtree, newtree))
2103                                return 1;
2104                        return reject_merge(oldtree, o);
2105                }
2106                return merged_entry(newtree, current, o);
2107        }
2108        return deleted_entry(oldtree, current, o);
2109}
2110
2111/*
2112 * Bind merge.
2113 *
2114 * Keep the index entries at stage0, collapse stage1 but make sure
2115 * stage0 does not have anything there.
2116 */
2117int bind_merge(const struct cache_entry * const *src,
2118               struct unpack_trees_options *o)
2119{
2120        const struct cache_entry *old = src[0];
2121        const struct cache_entry *a = src[1];
2122
2123        if (o->merge_size != 1)
2124                return error("Cannot do a bind merge of %d trees",
2125                             o->merge_size);
2126        if (a && old)
2127                return o->gently ? -1 :
2128                        error(ERRORMSG(o, ERROR_BIND_OVERLAP),
2129                              super_prefixed(a->name),
2130                              super_prefixed(old->name));
2131        if (!a)
2132                return keep_entry(old, o);
2133        else
2134                return merged_entry(a, NULL, o);
2135}
2136
2137/*
2138 * One-way merge.
2139 *
2140 * The rule is:
2141 * - take the stat information from stage0, take the data from stage1
2142 */
2143int oneway_merge(const struct cache_entry * const *src,
2144                 struct unpack_trees_options *o)
2145{
2146        const struct cache_entry *old = src[0];
2147        const struct cache_entry *a = src[1];
2148
2149        if (o->merge_size != 1)
2150                return error("Cannot do a oneway merge of %d trees",
2151                             o->merge_size);
2152
2153        if (!a || a == o->df_conflict_entry)
2154                return deleted_entry(old, old, o);
2155
2156        if (old && same(old, a)) {
2157                int update = 0;
2158                if (o->reset && o->update && !ce_uptodate(old) && !ce_skip_worktree(old)) {
2159                        struct stat st;
2160                        if (lstat(old->name, &st) ||
2161                            ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
2162                                update |= CE_UPDATE;
2163                }
2164                if (o->update && S_ISGITLINK(old->ce_mode) &&
2165                    should_update_submodules() && !verify_uptodate(old, o))
2166                        update |= CE_UPDATE;
2167                add_entry(o, old, update, 0);
2168                return 0;
2169        }
2170        return merged_entry(a, old, o);
2171}