unpack-trees.con commit Sync with 2.12.5 (1df0306)
   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#include "split-index.h"
  12#include "dir.h"
  13#include "submodule.h"
  14#include "submodule-config.h"
  15
  16/*
  17 * Error messages expected by scripts out of plumbing commands such as
  18 * read-tree.  Non-scripted Porcelain is not required to use these messages
  19 * and in fact are encouraged to reword them to better suit their particular
  20 * situation better.  See how "git checkout" and "git merge" replaces
  21 * them using setup_unpack_trees_porcelain(), for example.
  22 */
  23static const char *unpack_plumbing_errors[NB_UNPACK_TREES_ERROR_TYPES] = {
  24        /* ERROR_WOULD_OVERWRITE */
  25        "Entry '%s' would be overwritten by merge. Cannot merge.",
  26
  27        /* ERROR_NOT_UPTODATE_FILE */
  28        "Entry '%s' not uptodate. Cannot merge.",
  29
  30        /* ERROR_NOT_UPTODATE_DIR */
  31        "Updating '%s' would lose untracked files in it",
  32
  33        /* ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN */
  34        "Untracked working tree file '%s' would be overwritten by merge.",
  35
  36        /* ERROR_WOULD_LOSE_UNTRACKED_REMOVED */
  37        "Untracked working tree file '%s' would be removed by merge.",
  38
  39        /* ERROR_BIND_OVERLAP */
  40        "Entry '%s' overlaps with '%s'.  Cannot bind.",
  41
  42        /* ERROR_SPARSE_NOT_UPTODATE_FILE */
  43        "Entry '%s' not uptodate. Cannot update sparse checkout.",
  44
  45        /* ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN */
  46        "Working tree file '%s' would be overwritten by sparse checkout update.",
  47
  48        /* ERROR_WOULD_LOSE_ORPHANED_REMOVED */
  49        "Working tree file '%s' would be removed by sparse checkout update.",
  50
  51        /* ERROR_WOULD_LOSE_SUBMODULE */
  52        "Submodule '%s' cannot checkout new HEAD.",
  53};
  54
  55#define ERRORMSG(o,type) \
  56        ( ((o) && (o)->msgs[(type)]) \
  57          ? ((o)->msgs[(type)])      \
  58          : (unpack_plumbing_errors[(type)]) )
  59
  60static const char *super_prefixed(const char *path)
  61{
  62        /*
  63         * It is necessary and sufficient to have two static buffers
  64         * here, as the return value of this function is fed to
  65         * error() using the unpack_*_errors[] templates we see above.
  66         */
  67        static struct strbuf buf[2] = {STRBUF_INIT, STRBUF_INIT};
  68        static int super_prefix_len = -1;
  69        static unsigned idx = ARRAY_SIZE(buf) - 1;
  70
  71        if (super_prefix_len < 0) {
  72                const char *super_prefix = get_super_prefix();
  73                if (!super_prefix) {
  74                        super_prefix_len = 0;
  75                } else {
  76                        int i;
  77                        for (i = 0; i < ARRAY_SIZE(buf); i++)
  78                                strbuf_addstr(&buf[i], super_prefix);
  79                        super_prefix_len = buf[0].len;
  80                }
  81        }
  82
  83        if (!super_prefix_len)
  84                return path;
  85
  86        if (++idx >= ARRAY_SIZE(buf))
  87                idx = 0;
  88
  89        strbuf_setlen(&buf[idx], super_prefix_len);
  90        strbuf_addstr(&buf[idx], path);
  91
  92        return buf[idx].buf;
  93}
  94
  95void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
  96                                  const char *cmd)
  97{
  98        int i;
  99        const char **msgs = opts->msgs;
 100        const char *msg;
 101
 102        if (!strcmp(cmd, "checkout"))
 103                msg = advice_commit_before_merge
 104                      ? _("Your local changes to the following files would be overwritten by checkout:\n%%s"
 105                          "Please commit your changes or stash them before you switch branches.")
 106                      : _("Your local changes to the following files would be overwritten by checkout:\n%%s");
 107        else if (!strcmp(cmd, "merge"))
 108                msg = advice_commit_before_merge
 109                      ? _("Your local changes to the following files would be overwritten by merge:\n%%s"
 110                          "Please commit your changes or stash them before you merge.")
 111                      : _("Your local changes to the following files would be overwritten by merge:\n%%s");
 112        else
 113                msg = advice_commit_before_merge
 114                      ? _("Your local changes to the following files would be overwritten by %s:\n%%s"
 115                          "Please commit your changes or stash them before you %s.")
 116                      : _("Your local changes to the following files would be overwritten by %s:\n%%s");
 117        msgs[ERROR_WOULD_OVERWRITE] = msgs[ERROR_NOT_UPTODATE_FILE] =
 118                xstrfmt(msg, cmd, cmd);
 119
 120        msgs[ERROR_NOT_UPTODATE_DIR] =
 121                _("Updating the following directories would lose untracked files in them:\n%s");
 122
 123        if (!strcmp(cmd, "checkout"))
 124                msg = advice_commit_before_merge
 125                      ? _("The following untracked working tree files would be removed by checkout:\n%%s"
 126                          "Please move or remove them before you switch branches.")
 127                      : _("The following untracked working tree files would be removed by checkout:\n%%s");
 128        else if (!strcmp(cmd, "merge"))
 129                msg = advice_commit_before_merge
 130                      ? _("The following untracked working tree files would be removed by merge:\n%%s"
 131                          "Please move or remove them before you merge.")
 132                      : _("The following untracked working tree files would be removed by merge:\n%%s");
 133        else
 134                msg = advice_commit_before_merge
 135                      ? _("The following untracked working tree files would be removed by %s:\n%%s"
 136                          "Please move or remove them before you %s.")
 137                      : _("The following untracked working tree files would be removed by %s:\n%%s");
 138        msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = xstrfmt(msg, cmd, cmd);
 139
 140        if (!strcmp(cmd, "checkout"))
 141                msg = advice_commit_before_merge
 142                      ? _("The following untracked working tree files would be overwritten by checkout:\n%%s"
 143                          "Please move or remove them before you switch branches.")
 144                      : _("The following untracked working tree files would be overwritten by checkout:\n%%s");
 145        else if (!strcmp(cmd, "merge"))
 146                msg = advice_commit_before_merge
 147                      ? _("The following untracked working tree files would be overwritten by merge:\n%%s"
 148                          "Please move or remove them before you merge.")
 149                      : _("The following untracked working tree files would be overwritten by merge:\n%%s");
 150        else
 151                msg = advice_commit_before_merge
 152                      ? _("The following untracked working tree files would be overwritten by %s:\n%%s"
 153                          "Please move or remove them before you %s.")
 154                      : _("The following untracked working tree files would be overwritten by %s:\n%%s");
 155        msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = xstrfmt(msg, cmd, cmd);
 156
 157        /*
 158         * Special case: ERROR_BIND_OVERLAP refers to a pair of paths, we
 159         * cannot easily display it as a list.
 160         */
 161        msgs[ERROR_BIND_OVERLAP] = _("Entry '%s' overlaps with '%s'.  Cannot bind.");
 162
 163        msgs[ERROR_SPARSE_NOT_UPTODATE_FILE] =
 164                _("Cannot update sparse checkout: the following entries are not up-to-date:\n%s");
 165        msgs[ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN] =
 166                _("The following working tree files would be overwritten by sparse checkout update:\n%s");
 167        msgs[ERROR_WOULD_LOSE_ORPHANED_REMOVED] =
 168                _("The following working tree files would be removed by sparse checkout update:\n%s");
 169        msgs[ERROR_WOULD_LOSE_SUBMODULE] =
 170                _("Cannot update submodule:\n%s");
 171
 172        opts->show_all_errors = 1;
 173        /* rejected paths may not have a static buffer */
 174        for (i = 0; i < ARRAY_SIZE(opts->unpack_rejects); i++)
 175                opts->unpack_rejects[i].strdup_strings = 1;
 176}
 177
 178static int do_add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
 179                         unsigned int set, unsigned int clear)
 180{
 181        clear |= CE_HASHED;
 182
 183        if (set & CE_REMOVE)
 184                set |= CE_WT_REMOVE;
 185
 186        ce->ce_flags = (ce->ce_flags & ~clear) | set;
 187        return add_index_entry(&o->result, ce,
 188                               ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 189}
 190
 191static struct cache_entry *dup_entry(const struct cache_entry *ce)
 192{
 193        unsigned int size = ce_size(ce);
 194        struct cache_entry *new = xmalloc(size);
 195
 196        memcpy(new, ce, size);
 197        return new;
 198}
 199
 200static void add_entry(struct unpack_trees_options *o,
 201                      const struct cache_entry *ce,
 202                      unsigned int set, unsigned int clear)
 203{
 204        do_add_entry(o, dup_entry(ce), set, clear);
 205}
 206
 207/*
 208 * add error messages on path <path>
 209 * corresponding to the type <e> with the message <msg>
 210 * indicating if it should be display in porcelain or not
 211 */
 212static int add_rejected_path(struct unpack_trees_options *o,
 213                             enum unpack_trees_error_types e,
 214                             const char *path)
 215{
 216        if (!o->show_all_errors)
 217                return error(ERRORMSG(o, e), super_prefixed(path));
 218
 219        /*
 220         * Otherwise, insert in a list for future display by
 221         * display_error_msgs()
 222         */
 223        string_list_append(&o->unpack_rejects[e], path);
 224        return -1;
 225}
 226
 227/*
 228 * display all the error messages stored in a nice way
 229 */
 230static void display_error_msgs(struct unpack_trees_options *o)
 231{
 232        int e, i;
 233        int something_displayed = 0;
 234        for (e = 0; e < NB_UNPACK_TREES_ERROR_TYPES; e++) {
 235                struct string_list *rejects = &o->unpack_rejects[e];
 236                if (rejects->nr > 0) {
 237                        struct strbuf path = STRBUF_INIT;
 238                        something_displayed = 1;
 239                        for (i = 0; i < rejects->nr; i++)
 240                                strbuf_addf(&path, "\t%s\n", rejects->items[i].string);
 241                        error(ERRORMSG(o, e), super_prefixed(path.buf));
 242                        strbuf_release(&path);
 243                }
 244                string_list_clear(rejects, 0);
 245        }
 246        if (something_displayed)
 247                fprintf(stderr, _("Aborting\n"));
 248}
 249
 250static int check_submodule_move_head(const struct cache_entry *ce,
 251                                     const char *old_id,
 252                                     const char *new_id,
 253                                     struct unpack_trees_options *o)
 254{
 255        const struct submodule *sub = submodule_from_ce(ce);
 256        if (!sub)
 257                return 0;
 258
 259        switch (sub->update_strategy.type) {
 260        case SM_UPDATE_UNSPECIFIED:
 261        case SM_UPDATE_CHECKOUT:
 262                if (submodule_move_head(ce->name, old_id, new_id, SUBMODULE_MOVE_HEAD_DRY_RUN))
 263                        return o->gently ? -1 :
 264                                add_rejected_path(o, ERROR_WOULD_LOSE_SUBMODULE, ce->name);
 265                return 0;
 266        case SM_UPDATE_NONE:
 267                return 0;
 268        case SM_UPDATE_REBASE:
 269        case SM_UPDATE_MERGE:
 270        case SM_UPDATE_COMMAND:
 271        default:
 272                warning(_("submodule update strategy not supported for submodule '%s'"), ce->name);
 273                return -1;
 274        }
 275}
 276
 277static void reload_gitmodules_file(struct index_state *index,
 278                                   struct checkout *state)
 279{
 280        int i;
 281        for (i = 0; i < index->cache_nr; i++) {
 282                struct cache_entry *ce = index->cache[i];
 283                if (ce->ce_flags & CE_UPDATE) {
 284                        int r = strcmp(ce->name, ".gitmodules");
 285                        if (r < 0)
 286                                continue;
 287                        else if (r == 0) {
 288                                submodule_free();
 289                                checkout_entry(ce, state, NULL);
 290                                gitmodules_config();
 291                                git_config(submodule_config, NULL);
 292                        } else
 293                                break;
 294                }
 295        }
 296}
 297
 298/*
 299 * Unlink the last component and schedule the leading directories for
 300 * removal, such that empty directories get removed.
 301 */
 302static void unlink_entry(const struct cache_entry *ce)
 303{
 304        const struct submodule *sub = submodule_from_ce(ce);
 305        if (sub) {
 306                switch (sub->update_strategy.type) {
 307                case SM_UPDATE_UNSPECIFIED:
 308                case SM_UPDATE_CHECKOUT:
 309                case SM_UPDATE_REBASE:
 310                case SM_UPDATE_MERGE:
 311                        submodule_move_head(ce->name, "HEAD", NULL,
 312                                            SUBMODULE_MOVE_HEAD_FORCE);
 313                        break;
 314                case SM_UPDATE_NONE:
 315                case SM_UPDATE_COMMAND:
 316                        return; /* Do not touch the submodule. */
 317                }
 318        }
 319        if (!check_leading_path(ce->name, ce_namelen(ce)))
 320                return;
 321        if (remove_or_warn(ce->ce_mode, ce->name))
 322                return;
 323        schedule_dir_for_removal(ce->name, ce_namelen(ce));
 324}
 325
 326static struct progress *get_progress(struct unpack_trees_options *o)
 327{
 328        unsigned cnt = 0, total = 0;
 329        struct index_state *index = &o->result;
 330
 331        if (!o->update || !o->verbose_update)
 332                return NULL;
 333
 334        for (; cnt < index->cache_nr; cnt++) {
 335                const struct cache_entry *ce = index->cache[cnt];
 336                if (ce->ce_flags & (CE_UPDATE | CE_WT_REMOVE))
 337                        total++;
 338        }
 339
 340        return start_progress_delay(_("Checking out files"),
 341                                    total, 50, 1);
 342}
 343
 344static int check_updates(struct unpack_trees_options *o)
 345{
 346        unsigned cnt = 0;
 347        int errs = 0;
 348        struct progress *progress = NULL;
 349        struct index_state *index = &o->result;
 350        struct checkout state = CHECKOUT_INIT;
 351        int i;
 352
 353        state.force = 1;
 354        state.quiet = 1;
 355        state.refresh_cache = 1;
 356        state.istate = index;
 357
 358        progress = get_progress(o);
 359
 360        if (o->update)
 361                git_attr_set_direction(GIT_ATTR_CHECKOUT, index);
 362        for (i = 0; i < index->cache_nr; i++) {
 363                const struct cache_entry *ce = index->cache[i];
 364
 365                if (ce->ce_flags & CE_WT_REMOVE) {
 366                        display_progress(progress, ++cnt);
 367                        if (o->update && !o->dry_run)
 368                                unlink_entry(ce);
 369                }
 370        }
 371        remove_marked_cache_entries(index);
 372        remove_scheduled_dirs();
 373
 374        if (should_update_submodules() && o->update && !o->dry_run)
 375                reload_gitmodules_file(index, &state);
 376
 377        for (i = 0; i < index->cache_nr; i++) {
 378                struct cache_entry *ce = index->cache[i];
 379
 380                if (ce->ce_flags & CE_UPDATE) {
 381                        if (ce->ce_flags & CE_WT_REMOVE)
 382                                die("BUG: both update and delete flags are set on %s",
 383                                    ce->name);
 384                        display_progress(progress, ++cnt);
 385                        ce->ce_flags &= ~CE_UPDATE;
 386                        if (o->update && !o->dry_run) {
 387                                errs |= checkout_entry(ce, &state, NULL);
 388                        }
 389                }
 390        }
 391        stop_progress(&progress);
 392        if (o->update)
 393                git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
 394        return errs != 0;
 395}
 396
 397static int verify_uptodate_sparse(const struct cache_entry *ce,
 398                                  struct unpack_trees_options *o);
 399static int verify_absent_sparse(const struct cache_entry *ce,
 400                                enum unpack_trees_error_types,
 401                                struct unpack_trees_options *o);
 402
 403static int apply_sparse_checkout(struct index_state *istate,
 404                                 struct cache_entry *ce,
 405                                 struct unpack_trees_options *o)
 406{
 407        int was_skip_worktree = ce_skip_worktree(ce);
 408
 409        if (ce->ce_flags & CE_NEW_SKIP_WORKTREE)
 410                ce->ce_flags |= CE_SKIP_WORKTREE;
 411        else
 412                ce->ce_flags &= ~CE_SKIP_WORKTREE;
 413        if (was_skip_worktree != ce_skip_worktree(ce)) {
 414                ce->ce_flags |= CE_UPDATE_IN_BASE;
 415                istate->cache_changed |= CE_ENTRY_CHANGED;
 416        }
 417
 418        /*
 419         * if (!was_skip_worktree && !ce_skip_worktree()) {
 420         *      This is perfectly normal. Move on;
 421         * }
 422         */
 423
 424        /*
 425         * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
 426         * area as a result of ce_skip_worktree() shortcuts in
 427         * verify_absent() and verify_uptodate().
 428         * Make sure they don't modify worktree if they are already
 429         * outside checkout area
 430         */
 431        if (was_skip_worktree && ce_skip_worktree(ce)) {
 432                ce->ce_flags &= ~CE_UPDATE;
 433
 434                /*
 435                 * By default, when CE_REMOVE is on, CE_WT_REMOVE is also
 436                 * on to get that file removed from both index and worktree.
 437                 * If that file is already outside worktree area, don't
 438                 * bother remove it.
 439                 */
 440                if (ce->ce_flags & CE_REMOVE)
 441                        ce->ce_flags &= ~CE_WT_REMOVE;
 442        }
 443
 444        if (!was_skip_worktree && ce_skip_worktree(ce)) {
 445                /*
 446                 * If CE_UPDATE is set, verify_uptodate() must be called already
 447                 * also stat info may have lost after merged_entry() so calling
 448                 * verify_uptodate() again may fail
 449                 */
 450                if (!(ce->ce_flags & CE_UPDATE) && verify_uptodate_sparse(ce, o))
 451                        return -1;
 452                ce->ce_flags |= CE_WT_REMOVE;
 453                ce->ce_flags &= ~CE_UPDATE;
 454        }
 455        if (was_skip_worktree && !ce_skip_worktree(ce)) {
 456                if (verify_absent_sparse(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o))
 457                        return -1;
 458                ce->ce_flags |= CE_UPDATE;
 459        }
 460        return 0;
 461}
 462
 463static inline int call_unpack_fn(const struct cache_entry * const *src,
 464                                 struct unpack_trees_options *o)
 465{
 466        int ret = o->fn(src, o);
 467        if (ret > 0)
 468                ret = 0;
 469        return ret;
 470}
 471
 472static void mark_ce_used(struct cache_entry *ce, struct unpack_trees_options *o)
 473{
 474        ce->ce_flags |= CE_UNPACKED;
 475
 476        if (o->cache_bottom < o->src_index->cache_nr &&
 477            o->src_index->cache[o->cache_bottom] == ce) {
 478                int bottom = o->cache_bottom;
 479                while (bottom < o->src_index->cache_nr &&
 480                       o->src_index->cache[bottom]->ce_flags & CE_UNPACKED)
 481                        bottom++;
 482                o->cache_bottom = bottom;
 483        }
 484}
 485
 486static void mark_all_ce_unused(struct index_state *index)
 487{
 488        int i;
 489        for (i = 0; i < index->cache_nr; i++)
 490                index->cache[i]->ce_flags &= ~(CE_UNPACKED | CE_ADDED | CE_NEW_SKIP_WORKTREE);
 491}
 492
 493static int locate_in_src_index(const struct cache_entry *ce,
 494                               struct unpack_trees_options *o)
 495{
 496        struct index_state *index = o->src_index;
 497        int len = ce_namelen(ce);
 498        int pos = index_name_pos(index, ce->name, len);
 499        if (pos < 0)
 500                pos = -1 - pos;
 501        return pos;
 502}
 503
 504/*
 505 * We call unpack_index_entry() with an unmerged cache entry
 506 * only in diff-index, and it wants a single callback.  Skip
 507 * the other unmerged entry with the same name.
 508 */
 509static void mark_ce_used_same_name(struct cache_entry *ce,
 510                                   struct unpack_trees_options *o)
 511{
 512        struct index_state *index = o->src_index;
 513        int len = ce_namelen(ce);
 514        int pos;
 515
 516        for (pos = locate_in_src_index(ce, o); pos < index->cache_nr; pos++) {
 517                struct cache_entry *next = index->cache[pos];
 518                if (len != ce_namelen(next) ||
 519                    memcmp(ce->name, next->name, len))
 520                        break;
 521                mark_ce_used(next, o);
 522        }
 523}
 524
 525static struct cache_entry *next_cache_entry(struct unpack_trees_options *o)
 526{
 527        const struct index_state *index = o->src_index;
 528        int pos = o->cache_bottom;
 529
 530        while (pos < index->cache_nr) {
 531                struct cache_entry *ce = index->cache[pos];
 532                if (!(ce->ce_flags & CE_UNPACKED))
 533                        return ce;
 534                pos++;
 535        }
 536        return NULL;
 537}
 538
 539static void add_same_unmerged(const struct cache_entry *ce,
 540                              struct unpack_trees_options *o)
 541{
 542        struct index_state *index = o->src_index;
 543        int len = ce_namelen(ce);
 544        int pos = index_name_pos(index, ce->name, len);
 545
 546        if (0 <= pos)
 547                die("programming error in a caller of mark_ce_used_same_name");
 548        for (pos = -pos - 1; pos < index->cache_nr; pos++) {
 549                struct cache_entry *next = index->cache[pos];
 550                if (len != ce_namelen(next) ||
 551                    memcmp(ce->name, next->name, len))
 552                        break;
 553                add_entry(o, next, 0, 0);
 554                mark_ce_used(next, o);
 555        }
 556}
 557
 558static int unpack_index_entry(struct cache_entry *ce,
 559                              struct unpack_trees_options *o)
 560{
 561        const struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 562        int ret;
 563
 564        src[0] = ce;
 565
 566        mark_ce_used(ce, o);
 567        if (ce_stage(ce)) {
 568                if (o->skip_unmerged) {
 569                        add_entry(o, ce, 0, 0);
 570                        return 0;
 571                }
 572        }
 573        ret = call_unpack_fn(src, o);
 574        if (ce_stage(ce))
 575                mark_ce_used_same_name(ce, o);
 576        return ret;
 577}
 578
 579static int find_cache_pos(struct traverse_info *, const struct name_entry *);
 580
 581static void restore_cache_bottom(struct traverse_info *info, int bottom)
 582{
 583        struct unpack_trees_options *o = info->data;
 584
 585        if (o->diff_index_cached)
 586                return;
 587        o->cache_bottom = bottom;
 588}
 589
 590static int switch_cache_bottom(struct traverse_info *info)
 591{
 592        struct unpack_trees_options *o = info->data;
 593        int ret, pos;
 594
 595        if (o->diff_index_cached)
 596                return 0;
 597        ret = o->cache_bottom;
 598        pos = find_cache_pos(info->prev, &info->name);
 599
 600        if (pos < -1)
 601                o->cache_bottom = -2 - pos;
 602        else if (pos < 0)
 603                o->cache_bottom = o->src_index->cache_nr;
 604        return ret;
 605}
 606
 607static inline int are_same_oid(struct name_entry *name_j, struct name_entry *name_k)
 608{
 609        return name_j->oid && name_k->oid && !oidcmp(name_j->oid, name_k->oid);
 610}
 611
 612static int traverse_trees_recursive(int n, unsigned long dirmask,
 613                                    unsigned long df_conflicts,
 614                                    struct name_entry *names,
 615                                    struct traverse_info *info)
 616{
 617        int i, ret, bottom;
 618        int nr_buf = 0;
 619        struct tree_desc t[MAX_UNPACK_TREES];
 620        void *buf[MAX_UNPACK_TREES];
 621        struct traverse_info newinfo;
 622        struct name_entry *p;
 623
 624        p = names;
 625        while (!p->mode)
 626                p++;
 627
 628        newinfo = *info;
 629        newinfo.prev = info;
 630        newinfo.pathspec = info->pathspec;
 631        newinfo.name = *p;
 632        newinfo.pathlen += tree_entry_len(p) + 1;
 633        newinfo.df_conflicts |= df_conflicts;
 634
 635        /*
 636         * Fetch the tree from the ODB for each peer directory in the
 637         * n commits.
 638         *
 639         * For 2- and 3-way traversals, we try to avoid hitting the
 640         * ODB twice for the same OID.  This should yield a nice speed
 641         * up in checkouts and merges when the commits are similar.
 642         *
 643         * We don't bother doing the full O(n^2) search for larger n,
 644         * because wider traversals don't happen that often and we
 645         * avoid the search setup.
 646         *
 647         * When 2 peer OIDs are the same, we just copy the tree
 648         * descriptor data.  This implicitly borrows the buffer
 649         * data from the earlier cell.
 650         */
 651        for (i = 0; i < n; i++, dirmask >>= 1) {
 652                if (i > 0 && are_same_oid(&names[i], &names[i - 1]))
 653                        t[i] = t[i - 1];
 654                else if (i > 1 && are_same_oid(&names[i], &names[i - 2]))
 655                        t[i] = t[i - 2];
 656                else {
 657                        const unsigned char *sha1 = NULL;
 658                        if (dirmask & 1)
 659                                sha1 = names[i].oid->hash;
 660                        buf[nr_buf++] = fill_tree_descriptor(t+i, sha1);
 661                }
 662        }
 663
 664        bottom = switch_cache_bottom(&newinfo);
 665        ret = traverse_trees(n, t, &newinfo);
 666        restore_cache_bottom(&newinfo, bottom);
 667
 668        for (i = 0; i < nr_buf; i++)
 669                free(buf[i]);
 670
 671        return ret;
 672}
 673
 674/*
 675 * Compare the traverse-path to the cache entry without actually
 676 * having to generate the textual representation of the traverse
 677 * path.
 678 *
 679 * NOTE! This *only* compares up to the size of the traverse path
 680 * itself - the caller needs to do the final check for the cache
 681 * entry having more data at the end!
 682 */
 683static int do_compare_entry_piecewise(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 684{
 685        int len, pathlen, ce_len;
 686        const char *ce_name;
 687
 688        if (info->prev) {
 689                int cmp = do_compare_entry_piecewise(ce, info->prev,
 690                                                     &info->name);
 691                if (cmp)
 692                        return cmp;
 693        }
 694        pathlen = info->pathlen;
 695        ce_len = ce_namelen(ce);
 696
 697        /* If ce_len < pathlen then we must have previously hit "name == directory" entry */
 698        if (ce_len < pathlen)
 699                return -1;
 700
 701        ce_len -= pathlen;
 702        ce_name = ce->name + pathlen;
 703
 704        len = tree_entry_len(n);
 705        return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 706}
 707
 708static int do_compare_entry(const struct cache_entry *ce,
 709                            const struct traverse_info *info,
 710                            const struct name_entry *n)
 711{
 712        int len, pathlen, ce_len;
 713        const char *ce_name;
 714        int cmp;
 715
 716        /*
 717         * If we have not precomputed the traverse path, it is quicker
 718         * to avoid doing so.  But if we have precomputed it,
 719         * it is quicker to use the precomputed version.
 720         */
 721        if (!info->traverse_path)
 722                return do_compare_entry_piecewise(ce, info, n);
 723
 724        cmp = strncmp(ce->name, info->traverse_path, info->pathlen);
 725        if (cmp)
 726                return cmp;
 727
 728        pathlen = info->pathlen;
 729        ce_len = ce_namelen(ce);
 730
 731        if (ce_len < pathlen)
 732                return -1;
 733
 734        ce_len -= pathlen;
 735        ce_name = ce->name + pathlen;
 736
 737        len = tree_entry_len(n);
 738        return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 739}
 740
 741static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 742{
 743        int cmp = do_compare_entry(ce, info, n);
 744        if (cmp)
 745                return cmp;
 746
 747        /*
 748         * Even if the beginning compared identically, the ce should
 749         * compare as bigger than a directory leading up to it!
 750         */
 751        return ce_namelen(ce) > traverse_path_len(info, n);
 752}
 753
 754static int ce_in_traverse_path(const struct cache_entry *ce,
 755                               const struct traverse_info *info)
 756{
 757        if (!info->prev)
 758                return 1;
 759        if (do_compare_entry(ce, info->prev, &info->name))
 760                return 0;
 761        /*
 762         * If ce (blob) is the same name as the path (which is a tree
 763         * we will be descending into), it won't be inside it.
 764         */
 765        return (info->pathlen < ce_namelen(ce));
 766}
 767
 768static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
 769{
 770        int len = traverse_path_len(info, n);
 771        struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
 772
 773        ce->ce_mode = create_ce_mode(n->mode);
 774        ce->ce_flags = create_ce_flags(stage);
 775        ce->ce_namelen = len;
 776        oidcpy(&ce->oid, n->oid);
 777        make_traverse_path(ce->name, info, n);
 778
 779        return ce;
 780}
 781
 782static int unpack_nondirectories(int n, unsigned long mask,
 783                                 unsigned long dirmask,
 784                                 struct cache_entry **src,
 785                                 const struct name_entry *names,
 786                                 const struct traverse_info *info)
 787{
 788        int i;
 789        struct unpack_trees_options *o = info->data;
 790        unsigned long conflicts = info->df_conflicts | dirmask;
 791
 792        /* Do we have *only* directories? Nothing to do */
 793        if (mask == dirmask && !src[0])
 794                return 0;
 795
 796        /*
 797         * Ok, we've filled in up to any potential index entry in src[0],
 798         * now do the rest.
 799         */
 800        for (i = 0; i < n; i++) {
 801                int stage;
 802                unsigned int bit = 1ul << i;
 803                if (conflicts & bit) {
 804                        src[i + o->merge] = o->df_conflict_entry;
 805                        continue;
 806                }
 807                if (!(mask & bit))
 808                        continue;
 809                if (!o->merge)
 810                        stage = 0;
 811                else if (i + 1 < o->head_idx)
 812                        stage = 1;
 813                else if (i + 1 > o->head_idx)
 814                        stage = 3;
 815                else
 816                        stage = 2;
 817                src[i + o->merge] = create_ce_entry(info, names + i, stage);
 818        }
 819
 820        if (o->merge) {
 821                int rc = call_unpack_fn((const struct cache_entry * const *)src,
 822                                        o);
 823                for (i = 0; i < n; i++) {
 824                        struct cache_entry *ce = src[i + o->merge];
 825                        if (ce != o->df_conflict_entry)
 826                                free(ce);
 827                }
 828                return rc;
 829        }
 830
 831        for (i = 0; i < n; i++)
 832                if (src[i] && src[i] != o->df_conflict_entry)
 833                        if (do_add_entry(o, src[i], 0, 0))
 834                                return -1;
 835
 836        return 0;
 837}
 838
 839static int unpack_failed(struct unpack_trees_options *o, const char *message)
 840{
 841        discard_index(&o->result);
 842        if (!o->gently && !o->exiting_early) {
 843                if (message)
 844                        return error("%s", message);
 845                return -1;
 846        }
 847        return -1;
 848}
 849
 850/*
 851 * The tree traversal is looking at name p.  If we have a matching entry,
 852 * return it.  If name p is a directory in the index, do not return
 853 * anything, as we will want to match it when the traversal descends into
 854 * the directory.
 855 */
 856static int find_cache_pos(struct traverse_info *info,
 857                          const struct name_entry *p)
 858{
 859        int pos;
 860        struct unpack_trees_options *o = info->data;
 861        struct index_state *index = o->src_index;
 862        int pfxlen = info->pathlen;
 863        int p_len = tree_entry_len(p);
 864
 865        for (pos = o->cache_bottom; pos < index->cache_nr; pos++) {
 866                const struct cache_entry *ce = index->cache[pos];
 867                const char *ce_name, *ce_slash;
 868                int cmp, ce_len;
 869
 870                if (ce->ce_flags & CE_UNPACKED) {
 871                        /*
 872                         * cache_bottom entry is already unpacked, so
 873                         * we can never match it; don't check it
 874                         * again.
 875                         */
 876                        if (pos == o->cache_bottom)
 877                                ++o->cache_bottom;
 878                        continue;
 879                }
 880                if (!ce_in_traverse_path(ce, info)) {
 881                        /*
 882                         * Check if we can skip future cache checks
 883                         * (because we're already past all possible
 884                         * entries in the traverse path).
 885                         */
 886                        if (info->traverse_path) {
 887                                if (strncmp(ce->name, info->traverse_path,
 888                                            info->pathlen) > 0)
 889                                        break;
 890                        }
 891                        continue;
 892                }
 893                ce_name = ce->name + pfxlen;
 894                ce_slash = strchr(ce_name, '/');
 895                if (ce_slash)
 896                        ce_len = ce_slash - ce_name;
 897                else
 898                        ce_len = ce_namelen(ce) - pfxlen;
 899                cmp = name_compare(p->path, p_len, ce_name, ce_len);
 900                /*
 901                 * Exact match; if we have a directory we need to
 902                 * delay returning it.
 903                 */
 904                if (!cmp)
 905                        return ce_slash ? -2 - pos : pos;
 906                if (0 < cmp)
 907                        continue; /* keep looking */
 908                /*
 909                 * ce_name sorts after p->path; could it be that we
 910                 * have files under p->path directory in the index?
 911                 * E.g.  ce_name == "t-i", and p->path == "t"; we may
 912                 * have "t/a" in the index.
 913                 */
 914                if (p_len < ce_len && !memcmp(ce_name, p->path, p_len) &&
 915                    ce_name[p_len] < '/')
 916                        continue; /* keep looking */
 917                break;
 918        }
 919        return -1;
 920}
 921
 922static struct cache_entry *find_cache_entry(struct traverse_info *info,
 923                                            const struct name_entry *p)
 924{
 925        int pos = find_cache_pos(info, p);
 926        struct unpack_trees_options *o = info->data;
 927
 928        if (0 <= pos)
 929                return o->src_index->cache[pos];
 930        else
 931                return NULL;
 932}
 933
 934static void debug_path(struct traverse_info *info)
 935{
 936        if (info->prev) {
 937                debug_path(info->prev);
 938                if (*info->prev->name.path)
 939                        putchar('/');
 940        }
 941        printf("%s", info->name.path);
 942}
 943
 944static void debug_name_entry(int i, struct name_entry *n)
 945{
 946        printf("ent#%d %06o %s\n", i,
 947               n->path ? n->mode : 0,
 948               n->path ? n->path : "(missing)");
 949}
 950
 951static void debug_unpack_callback(int n,
 952                                  unsigned long mask,
 953                                  unsigned long dirmask,
 954                                  struct name_entry *names,
 955                                  struct traverse_info *info)
 956{
 957        int i;
 958        printf("* unpack mask %lu, dirmask %lu, cnt %d ",
 959               mask, dirmask, n);
 960        debug_path(info);
 961        putchar('\n');
 962        for (i = 0; i < n; i++)
 963                debug_name_entry(i, names + i);
 964}
 965
 966static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
 967{
 968        struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 969        struct unpack_trees_options *o = info->data;
 970        const struct name_entry *p = names;
 971
 972        /* Find first entry with a real name (we could use "mask" too) */
 973        while (!p->mode)
 974                p++;
 975
 976        if (o->debug_unpack)
 977                debug_unpack_callback(n, mask, dirmask, names, info);
 978
 979        /* Are we supposed to look at the index too? */
 980        if (o->merge) {
 981                while (1) {
 982                        int cmp;
 983                        struct cache_entry *ce;
 984
 985                        if (o->diff_index_cached)
 986                                ce = next_cache_entry(o);
 987                        else
 988                                ce = find_cache_entry(info, p);
 989
 990                        if (!ce)
 991                                break;
 992                        cmp = compare_entry(ce, info, p);
 993                        if (cmp < 0) {
 994                                if (unpack_index_entry(ce, o) < 0)
 995                                        return unpack_failed(o, NULL);
 996                                continue;
 997                        }
 998                        if (!cmp) {
 999                                if (ce_stage(ce)) {
1000                                        /*
1001                                         * If we skip unmerged index
1002                                         * entries, we'll skip this
1003                                         * entry *and* the tree
1004                                         * entries associated with it!
1005                                         */
1006                                        if (o->skip_unmerged) {
1007                                                add_same_unmerged(ce, o);
1008                                                return mask;
1009                                        }
1010                                }
1011                                src[0] = ce;
1012                        }
1013                        break;
1014                }
1015        }
1016
1017        if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
1018                return -1;
1019
1020        if (o->merge && src[0]) {
1021                if (ce_stage(src[0]))
1022                        mark_ce_used_same_name(src[0], o);
1023                else
1024                        mark_ce_used(src[0], o);
1025        }
1026
1027        /* Now handle any directories.. */
1028        if (dirmask) {
1029                /* special case: "diff-index --cached" looking at a tree */
1030                if (o->diff_index_cached &&
1031                    n == 1 && dirmask == 1 && S_ISDIR(names->mode)) {
1032                        int matches;
1033                        matches = cache_tree_matches_traversal(o->src_index->cache_tree,
1034                                                               names, info);
1035                        /*
1036                         * Everything under the name matches; skip the
1037                         * entire hierarchy.  diff_index_cached codepath
1038                         * special cases D/F conflicts in such a way that
1039                         * it does not do any look-ahead, so this is safe.
1040                         */
1041                        if (matches) {
1042                                o->cache_bottom += matches;
1043                                return mask;
1044                        }
1045                }
1046
1047                if (traverse_trees_recursive(n, dirmask, mask & ~dirmask,
1048                                             names, info) < 0)
1049                        return -1;
1050                return mask;
1051        }
1052
1053        return mask;
1054}
1055
1056static int clear_ce_flags_1(struct cache_entry **cache, int nr,
1057                            struct strbuf *prefix,
1058                            int select_mask, int clear_mask,
1059                            struct exclude_list *el, int defval);
1060
1061/* Whole directory matching */
1062static int clear_ce_flags_dir(struct cache_entry **cache, int nr,
1063                              struct strbuf *prefix,
1064                              char *basename,
1065                              int select_mask, int clear_mask,
1066                              struct exclude_list *el, int defval)
1067{
1068        struct cache_entry **cache_end;
1069        int dtype = DT_DIR;
1070        int ret = is_excluded_from_list(prefix->buf, prefix->len,
1071                                        basename, &dtype, el);
1072        int rc;
1073
1074        strbuf_addch(prefix, '/');
1075
1076        /* If undecided, use matching result of parent dir in defval */
1077        if (ret < 0)
1078                ret = defval;
1079
1080        for (cache_end = cache; cache_end != cache + nr; cache_end++) {
1081                struct cache_entry *ce = *cache_end;
1082                if (strncmp(ce->name, prefix->buf, prefix->len))
1083                        break;
1084        }
1085
1086        /*
1087         * TODO: check el, if there are no patterns that may conflict
1088         * with ret (iow, we know in advance the incl/excl
1089         * decision for the entire directory), clear flag here without
1090         * calling clear_ce_flags_1(). That function will call
1091         * the expensive is_excluded_from_list() on every entry.
1092         */
1093        rc = clear_ce_flags_1(cache, cache_end - cache,
1094                              prefix,
1095                              select_mask, clear_mask,
1096                              el, ret);
1097        strbuf_setlen(prefix, prefix->len - 1);
1098        return rc;
1099}
1100
1101/*
1102 * Traverse the index, find every entry that matches according to
1103 * o->el. Do "ce_flags &= ~clear_mask" on those entries. Return the
1104 * number of traversed entries.
1105 *
1106 * If select_mask is non-zero, only entries whose ce_flags has on of
1107 * those bits enabled are traversed.
1108 *
1109 * cache        : pointer to an index entry
1110 * prefix_len   : an offset to its path
1111 *
1112 * The current path ("prefix") including the trailing '/' is
1113 *   cache[0]->name[0..(prefix_len-1)]
1114 * Top level path has prefix_len zero.
1115 */
1116static int clear_ce_flags_1(struct cache_entry **cache, int nr,
1117                            struct strbuf *prefix,
1118                            int select_mask, int clear_mask,
1119                            struct exclude_list *el, int defval)
1120{
1121        struct cache_entry **cache_end = cache + nr;
1122
1123        /*
1124         * Process all entries that have the given prefix and meet
1125         * select_mask condition
1126         */
1127        while(cache != cache_end) {
1128                struct cache_entry *ce = *cache;
1129                const char *name, *slash;
1130                int len, dtype, ret;
1131
1132                if (select_mask && !(ce->ce_flags & select_mask)) {
1133                        cache++;
1134                        continue;
1135                }
1136
1137                if (prefix->len && strncmp(ce->name, prefix->buf, prefix->len))
1138                        break;
1139
1140                name = ce->name + prefix->len;
1141                slash = strchr(name, '/');
1142
1143                /* If it's a directory, try whole directory match first */
1144                if (slash) {
1145                        int processed;
1146
1147                        len = slash - name;
1148                        strbuf_add(prefix, name, len);
1149
1150                        processed = clear_ce_flags_dir(cache, cache_end - cache,
1151                                                       prefix,
1152                                                       prefix->buf + prefix->len - len,
1153                                                       select_mask, clear_mask,
1154                                                       el, defval);
1155
1156                        /* clear_c_f_dir eats a whole dir already? */
1157                        if (processed) {
1158                                cache += processed;
1159                                strbuf_setlen(prefix, prefix->len - len);
1160                                continue;
1161                        }
1162
1163                        strbuf_addch(prefix, '/');
1164                        cache += clear_ce_flags_1(cache, cache_end - cache,
1165                                                  prefix,
1166                                                  select_mask, clear_mask, el, defval);
1167                        strbuf_setlen(prefix, prefix->len - len - 1);
1168                        continue;
1169                }
1170
1171                /* Non-directory */
1172                dtype = ce_to_dtype(ce);
1173                ret = is_excluded_from_list(ce->name, ce_namelen(ce),
1174                                            name, &dtype, el);
1175                if (ret < 0)
1176                        ret = defval;
1177                if (ret > 0)
1178                        ce->ce_flags &= ~clear_mask;
1179                cache++;
1180        }
1181        return nr - (cache_end - cache);
1182}
1183
1184static int clear_ce_flags(struct cache_entry **cache, int nr,
1185                            int select_mask, int clear_mask,
1186                            struct exclude_list *el)
1187{
1188        static struct strbuf prefix = STRBUF_INIT;
1189
1190        strbuf_reset(&prefix);
1191
1192        return clear_ce_flags_1(cache, nr,
1193                                &prefix,
1194                                select_mask, clear_mask,
1195                                el, 0);
1196}
1197
1198/*
1199 * Set/Clear CE_NEW_SKIP_WORKTREE according to $GIT_DIR/info/sparse-checkout
1200 */
1201static void mark_new_skip_worktree(struct exclude_list *el,
1202                                   struct index_state *the_index,
1203                                   int select_flag, int skip_wt_flag)
1204{
1205        int i;
1206
1207        /*
1208         * 1. Pretend the narrowest worktree: only unmerged entries
1209         * are checked out
1210         */
1211        for (i = 0; i < the_index->cache_nr; i++) {
1212                struct cache_entry *ce = the_index->cache[i];
1213
1214                if (select_flag && !(ce->ce_flags & select_flag))
1215                        continue;
1216
1217                if (!ce_stage(ce))
1218                        ce->ce_flags |= skip_wt_flag;
1219                else
1220                        ce->ce_flags &= ~skip_wt_flag;
1221        }
1222
1223        /*
1224         * 2. Widen worktree according to sparse-checkout file.
1225         * Matched entries will have skip_wt_flag cleared (i.e. "in")
1226         */
1227        clear_ce_flags(the_index->cache, the_index->cache_nr,
1228                       select_flag, skip_wt_flag, el);
1229}
1230
1231static int verify_absent(const struct cache_entry *,
1232                         enum unpack_trees_error_types,
1233                         struct unpack_trees_options *);
1234/*
1235 * N-way merge "len" trees.  Returns 0 on success, -1 on failure to manipulate the
1236 * resulting index, -2 on failure to reflect the changes to the work tree.
1237 *
1238 * CE_ADDED, CE_UNPACKED and CE_NEW_SKIP_WORKTREE are used internally
1239 */
1240int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
1241{
1242        int i, ret;
1243        static struct cache_entry *dfc;
1244        struct exclude_list el;
1245
1246        if (len > MAX_UNPACK_TREES)
1247                die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
1248
1249        memset(&el, 0, sizeof(el));
1250        if (!core_apply_sparse_checkout || !o->update)
1251                o->skip_sparse_checkout = 1;
1252        if (!o->skip_sparse_checkout) {
1253                char *sparse = git_pathdup("info/sparse-checkout");
1254                if (add_excludes_from_file_to_list(sparse, "", 0, &el, 0) < 0)
1255                        o->skip_sparse_checkout = 1;
1256                else
1257                        o->el = &el;
1258                free(sparse);
1259        }
1260
1261        memset(&o->result, 0, sizeof(o->result));
1262        o->result.initialized = 1;
1263        o->result.timestamp.sec = o->src_index->timestamp.sec;
1264        o->result.timestamp.nsec = o->src_index->timestamp.nsec;
1265        o->result.version = o->src_index->version;
1266        o->result.split_index = o->src_index->split_index;
1267        if (o->result.split_index)
1268                o->result.split_index->refcount++;
1269        hashcpy(o->result.sha1, o->src_index->sha1);
1270        o->merge_size = len;
1271        mark_all_ce_unused(o->src_index);
1272
1273        /*
1274         * Sparse checkout loop #1: set NEW_SKIP_WORKTREE on existing entries
1275         */
1276        if (!o->skip_sparse_checkout)
1277                mark_new_skip_worktree(o->el, o->src_index, 0, CE_NEW_SKIP_WORKTREE);
1278
1279        if (!dfc)
1280                dfc = xcalloc(1, cache_entry_size(0));
1281        o->df_conflict_entry = dfc;
1282
1283        if (len) {
1284                const char *prefix = o->prefix ? o->prefix : "";
1285                struct traverse_info info;
1286
1287                setup_traverse_info(&info, prefix);
1288                info.fn = unpack_callback;
1289                info.data = o;
1290                info.show_all_errors = o->show_all_errors;
1291                info.pathspec = o->pathspec;
1292
1293                if (o->prefix) {
1294                        /*
1295                         * Unpack existing index entries that sort before the
1296                         * prefix the tree is spliced into.  Note that o->merge
1297                         * is always true in this case.
1298                         */
1299                        while (1) {
1300                                struct cache_entry *ce = next_cache_entry(o);
1301                                if (!ce)
1302                                        break;
1303                                if (ce_in_traverse_path(ce, &info))
1304                                        break;
1305                                if (unpack_index_entry(ce, o) < 0)
1306                                        goto return_failed;
1307                        }
1308                }
1309
1310                if (traverse_trees(len, t, &info) < 0)
1311                        goto return_failed;
1312        }
1313
1314        /* Any left-over entries in the index? */
1315        if (o->merge) {
1316                while (1) {
1317                        struct cache_entry *ce = next_cache_entry(o);
1318                        if (!ce)
1319                                break;
1320                        if (unpack_index_entry(ce, o) < 0)
1321                                goto return_failed;
1322                }
1323        }
1324        mark_all_ce_unused(o->src_index);
1325
1326        if (o->trivial_merges_only && o->nontrivial_merge) {
1327                ret = unpack_failed(o, "Merge requires file-level merging");
1328                goto done;
1329        }
1330
1331        if (!o->skip_sparse_checkout) {
1332                int empty_worktree = 1;
1333
1334                /*
1335                 * Sparse checkout loop #2: set NEW_SKIP_WORKTREE on entries not in loop #1
1336                 * If the will have NEW_SKIP_WORKTREE, also set CE_SKIP_WORKTREE
1337                 * so apply_sparse_checkout() won't attempt to remove it from worktree
1338                 */
1339                mark_new_skip_worktree(o->el, &o->result, CE_ADDED, CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1340
1341                ret = 0;
1342                for (i = 0; i < o->result.cache_nr; i++) {
1343                        struct cache_entry *ce = o->result.cache[i];
1344
1345                        /*
1346                         * Entries marked with CE_ADDED in merged_entry() do not have
1347                         * verify_absent() check (the check is effectively disabled
1348                         * because CE_NEW_SKIP_WORKTREE is set unconditionally).
1349                         *
1350                         * Do the real check now because we have had
1351                         * correct CE_NEW_SKIP_WORKTREE
1352                         */
1353                        if (ce->ce_flags & CE_ADDED &&
1354                            verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1355                                if (!o->show_all_errors)
1356                                        goto return_failed;
1357                                ret = -1;
1358                        }
1359
1360                        if (apply_sparse_checkout(&o->result, ce, o)) {
1361                                if (!o->show_all_errors)
1362                                        goto return_failed;
1363                                ret = -1;
1364                        }
1365                        if (!ce_skip_worktree(ce))
1366                                empty_worktree = 0;
1367
1368                }
1369                if (ret < 0)
1370                        goto return_failed;
1371                /*
1372                 * Sparse checkout is meant to narrow down checkout area
1373                 * but it does not make sense to narrow down to empty working
1374                 * tree. This is usually a mistake in sparse checkout rules.
1375                 * Do not allow users to do that.
1376                 */
1377                if (o->result.cache_nr && empty_worktree) {
1378                        ret = unpack_failed(o, "Sparse checkout leaves no entry on working directory");
1379                        goto done;
1380                }
1381        }
1382
1383        o->src_index = NULL;
1384        ret = check_updates(o) ? (-2) : 0;
1385        if (o->dst_index) {
1386                if (!ret) {
1387                        if (!o->result.cache_tree)
1388                                o->result.cache_tree = cache_tree();
1389                        if (!cache_tree_fully_valid(o->result.cache_tree))
1390                                cache_tree_update(&o->result,
1391                                                  WRITE_TREE_SILENT |
1392                                                  WRITE_TREE_REPAIR);
1393                }
1394                discard_index(o->dst_index);
1395                *o->dst_index = o->result;
1396        } else {
1397                discard_index(&o->result);
1398        }
1399
1400done:
1401        clear_exclude_list(&el);
1402        return ret;
1403
1404return_failed:
1405        if (o->show_all_errors)
1406                display_error_msgs(o);
1407        mark_all_ce_unused(o->src_index);
1408        ret = unpack_failed(o, NULL);
1409        if (o->exiting_early)
1410                ret = 0;
1411        goto done;
1412}
1413
1414/* Here come the merge functions */
1415
1416static int reject_merge(const struct cache_entry *ce,
1417                        struct unpack_trees_options *o)
1418{
1419        return o->gently ? -1 :
1420                add_rejected_path(o, ERROR_WOULD_OVERWRITE, ce->name);
1421}
1422
1423static int same(const struct cache_entry *a, const struct cache_entry *b)
1424{
1425        if (!!a != !!b)
1426                return 0;
1427        if (!a && !b)
1428                return 1;
1429        if ((a->ce_flags | b->ce_flags) & CE_CONFLICTED)
1430                return 0;
1431        return a->ce_mode == b->ce_mode &&
1432               !oidcmp(&a->oid, &b->oid);
1433}
1434
1435
1436/*
1437 * When a CE gets turned into an unmerged entry, we
1438 * want it to be up-to-date
1439 */
1440static int verify_uptodate_1(const struct cache_entry *ce,
1441                             struct unpack_trees_options *o,
1442                             enum unpack_trees_error_types error_type)
1443{
1444        struct stat st;
1445
1446        if (o->index_only)
1447                return 0;
1448
1449        /*
1450         * CE_VALID and CE_SKIP_WORKTREE cheat, we better check again
1451         * if this entry is truly up-to-date because this file may be
1452         * overwritten.
1453         */
1454        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
1455                ; /* keep checking */
1456        else if (o->reset || ce_uptodate(ce))
1457                return 0;
1458
1459        if (!lstat(ce->name, &st)) {
1460                int flags = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE;
1461                unsigned changed = ie_match_stat(o->src_index, ce, &st, flags);
1462
1463                if (submodule_from_ce(ce)) {
1464                        int r = check_submodule_move_head(ce,
1465                                "HEAD", oid_to_hex(&ce->oid), o);
1466                        if (r)
1467                                return o->gently ? -1 :
1468                                        add_rejected_path(o, error_type, ce->name);
1469                        return 0;
1470                }
1471
1472                if (!changed)
1473                        return 0;
1474                /*
1475                 * Historic default policy was to allow submodule to be out
1476                 * of sync wrt the superproject index. If the submodule was
1477                 * not considered interesting above, we don't care here.
1478                 */
1479                if (S_ISGITLINK(ce->ce_mode))
1480                        return 0;
1481
1482                errno = 0;
1483        }
1484        if (errno == ENOENT)
1485                return 0;
1486        return o->gently ? -1 :
1487                add_rejected_path(o, error_type, ce->name);
1488}
1489
1490static int verify_uptodate(const struct cache_entry *ce,
1491                           struct unpack_trees_options *o)
1492{
1493        if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1494                return 0;
1495        return verify_uptodate_1(ce, o, ERROR_NOT_UPTODATE_FILE);
1496}
1497
1498static int verify_uptodate_sparse(const struct cache_entry *ce,
1499                                  struct unpack_trees_options *o)
1500{
1501        return verify_uptodate_1(ce, o, ERROR_SPARSE_NOT_UPTODATE_FILE);
1502}
1503
1504static void invalidate_ce_path(const struct cache_entry *ce,
1505                               struct unpack_trees_options *o)
1506{
1507        if (!ce)
1508                return;
1509        cache_tree_invalidate_path(o->src_index, ce->name);
1510        untracked_cache_invalidate_path(o->src_index, ce->name);
1511}
1512
1513/*
1514 * Check that checking out ce->sha1 in subdir ce->name is not
1515 * going to overwrite any working files.
1516 *
1517 * Currently, git does not checkout subprojects during a superproject
1518 * checkout, so it is not going to overwrite anything.
1519 */
1520static int verify_clean_submodule(const char *old_sha1,
1521                                  const struct cache_entry *ce,
1522                                  enum unpack_trees_error_types error_type,
1523                                  struct unpack_trees_options *o)
1524{
1525        if (!submodule_from_ce(ce))
1526                return 0;
1527
1528        return check_submodule_move_head(ce, old_sha1,
1529                                         oid_to_hex(&ce->oid), o);
1530}
1531
1532static int verify_clean_subdirectory(const struct cache_entry *ce,
1533                                     enum unpack_trees_error_types error_type,
1534                                     struct unpack_trees_options *o)
1535{
1536        /*
1537         * we are about to extract "ce->name"; we would not want to lose
1538         * anything in the existing directory there.
1539         */
1540        int namelen;
1541        int i;
1542        struct dir_struct d;
1543        char *pathbuf;
1544        int cnt = 0;
1545
1546        if (S_ISGITLINK(ce->ce_mode)) {
1547                unsigned char sha1[20];
1548                int sub_head = resolve_gitlink_ref(ce->name, "HEAD", sha1);
1549                /*
1550                 * If we are not going to update the submodule, then
1551                 * we don't care.
1552                 */
1553                if (!sub_head && !hashcmp(sha1, ce->oid.hash))
1554                        return 0;
1555                return verify_clean_submodule(sub_head ? NULL : sha1_to_hex(sha1),
1556                                              ce, error_type, o);
1557        }
1558
1559        /*
1560         * First let's make sure we do not have a local modification
1561         * in that directory.
1562         */
1563        namelen = ce_namelen(ce);
1564        for (i = locate_in_src_index(ce, o);
1565             i < o->src_index->cache_nr;
1566             i++) {
1567                struct cache_entry *ce2 = o->src_index->cache[i];
1568                int len = ce_namelen(ce2);
1569                if (len < namelen ||
1570                    strncmp(ce->name, ce2->name, namelen) ||
1571                    ce2->name[namelen] != '/')
1572                        break;
1573                /*
1574                 * ce2->name is an entry in the subdirectory to be
1575                 * removed.
1576                 */
1577                if (!ce_stage(ce2)) {
1578                        if (verify_uptodate(ce2, o))
1579                                return -1;
1580                        add_entry(o, ce2, CE_REMOVE, 0);
1581                        mark_ce_used(ce2, o);
1582                }
1583                cnt++;
1584        }
1585
1586        /*
1587         * Then we need to make sure that we do not lose a locally
1588         * present file that is not ignored.
1589         */
1590        pathbuf = xstrfmt("%.*s/", namelen, ce->name);
1591
1592        memset(&d, 0, sizeof(d));
1593        if (o->dir)
1594                d.exclude_per_dir = o->dir->exclude_per_dir;
1595        i = read_directory(&d, pathbuf, namelen+1, NULL);
1596        if (i)
1597                return o->gently ? -1 :
1598                        add_rejected_path(o, ERROR_NOT_UPTODATE_DIR, ce->name);
1599        free(pathbuf);
1600        return cnt;
1601}
1602
1603/*
1604 * This gets called when there was no index entry for the tree entry 'dst',
1605 * but we found a file in the working tree that 'lstat()' said was fine,
1606 * and we're on a case-insensitive filesystem.
1607 *
1608 * See if we can find a case-insensitive match in the index that also
1609 * matches the stat information, and assume it's that other file!
1610 */
1611static int icase_exists(struct unpack_trees_options *o, const char *name, int len, struct stat *st)
1612{
1613        const struct cache_entry *src;
1614
1615        src = index_file_exists(o->src_index, name, len, 1);
1616        return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
1617}
1618
1619static int check_ok_to_remove(const char *name, int len, int dtype,
1620                              const struct cache_entry *ce, struct stat *st,
1621                              enum unpack_trees_error_types error_type,
1622                              struct unpack_trees_options *o)
1623{
1624        const struct cache_entry *result;
1625
1626        /*
1627         * It may be that the 'lstat()' succeeded even though
1628         * target 'ce' was absent, because there is an old
1629         * entry that is different only in case..
1630         *
1631         * Ignore that lstat() if it matches.
1632         */
1633        if (ignore_case && icase_exists(o, name, len, st))
1634                return 0;
1635
1636        if (o->dir &&
1637            is_excluded(o->dir, name, &dtype))
1638                /*
1639                 * ce->name is explicitly excluded, so it is Ok to
1640                 * overwrite it.
1641                 */
1642                return 0;
1643        if (S_ISDIR(st->st_mode)) {
1644                /*
1645                 * We are checking out path "foo" and
1646                 * found "foo/." in the working tree.
1647                 * This is tricky -- if we have modified
1648                 * files that are in "foo/" we would lose
1649                 * them.
1650                 */
1651                if (verify_clean_subdirectory(ce, error_type, o) < 0)
1652                        return -1;
1653                return 0;
1654        }
1655
1656        /*
1657         * The previous round may already have decided to
1658         * delete this path, which is in a subdirectory that
1659         * is being replaced with a blob.
1660         */
1661        result = index_file_exists(&o->result, name, len, 0);
1662        if (result) {
1663                if (result->ce_flags & CE_REMOVE)
1664                        return 0;
1665        }
1666
1667        return o->gently ? -1 :
1668                add_rejected_path(o, error_type, name);
1669}
1670
1671/*
1672 * We do not want to remove or overwrite a working tree file that
1673 * is not tracked, unless it is ignored.
1674 */
1675static int verify_absent_1(const struct cache_entry *ce,
1676                           enum unpack_trees_error_types error_type,
1677                           struct unpack_trees_options *o)
1678{
1679        int len;
1680        struct stat st;
1681
1682        if (o->index_only || o->reset || !o->update)
1683                return 0;
1684
1685        len = check_leading_path(ce->name, ce_namelen(ce));
1686        if (!len)
1687                return 0;
1688        else if (len > 0) {
1689                char *path;
1690                int ret;
1691
1692                path = xmemdupz(ce->name, len);
1693                if (lstat(path, &st))
1694                        ret = error_errno("cannot stat '%s'", path);
1695                else {
1696                        if (submodule_from_ce(ce))
1697                                ret = check_submodule_move_head(ce,
1698                                                                oid_to_hex(&ce->oid),
1699                                                                NULL, o);
1700                        else
1701                                ret = check_ok_to_remove(path, len, DT_UNKNOWN, NULL,
1702                                                         &st, error_type, o);
1703                }
1704                free(path);
1705                return ret;
1706        } else if (lstat(ce->name, &st)) {
1707                if (errno != ENOENT)
1708                        return error_errno("cannot stat '%s'", ce->name);
1709                return 0;
1710        } else {
1711                if (submodule_from_ce(ce))
1712                        return check_submodule_move_head(ce, oid_to_hex(&ce->oid),
1713                                                         NULL, o);
1714
1715                return check_ok_to_remove(ce->name, ce_namelen(ce),
1716                                          ce_to_dtype(ce), ce, &st,
1717                                          error_type, o);
1718        }
1719}
1720
1721static int verify_absent(const struct cache_entry *ce,
1722                         enum unpack_trees_error_types error_type,
1723                         struct unpack_trees_options *o)
1724{
1725        if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1726                return 0;
1727        return verify_absent_1(ce, error_type, o);
1728}
1729
1730static int verify_absent_sparse(const struct cache_entry *ce,
1731                                enum unpack_trees_error_types error_type,
1732                                struct unpack_trees_options *o)
1733{
1734        enum unpack_trees_error_types orphaned_error = error_type;
1735        if (orphaned_error == ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN)
1736                orphaned_error = ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN;
1737
1738        return verify_absent_1(ce, orphaned_error, o);
1739}
1740
1741static int merged_entry(const struct cache_entry *ce,
1742                        const struct cache_entry *old,
1743                        struct unpack_trees_options *o)
1744{
1745        int update = CE_UPDATE;
1746        struct cache_entry *merge = dup_entry(ce);
1747
1748        if (!old) {
1749                /*
1750                 * New index entries. In sparse checkout, the following
1751                 * verify_absent() will be delayed until after
1752                 * traverse_trees() finishes in unpack_trees(), then:
1753                 *
1754                 *  - CE_NEW_SKIP_WORKTREE will be computed correctly
1755                 *  - verify_absent() be called again, this time with
1756                 *    correct CE_NEW_SKIP_WORKTREE
1757                 *
1758                 * verify_absent() call here does nothing in sparse
1759                 * checkout (i.e. o->skip_sparse_checkout == 0)
1760                 */
1761                update |= CE_ADDED;
1762                merge->ce_flags |= CE_NEW_SKIP_WORKTREE;
1763
1764                if (verify_absent(merge,
1765                                  ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1766                        free(merge);
1767                        return -1;
1768                }
1769                invalidate_ce_path(merge, o);
1770
1771                if (submodule_from_ce(ce)) {
1772                        int ret = check_submodule_move_head(ce, NULL,
1773                                                            oid_to_hex(&ce->oid),
1774                                                            o);
1775                        if (ret)
1776                                return ret;
1777                }
1778
1779        } else if (!(old->ce_flags & CE_CONFLICTED)) {
1780                /*
1781                 * See if we can re-use the old CE directly?
1782                 * That way we get the uptodate stat info.
1783                 *
1784                 * This also removes the UPDATE flag on a match; otherwise
1785                 * we will end up overwriting local changes in the work tree.
1786                 */
1787                if (same(old, merge)) {
1788                        copy_cache_entry(merge, old);
1789                        update = 0;
1790                } else {
1791                        if (verify_uptodate(old, o)) {
1792                                free(merge);
1793                                return -1;
1794                        }
1795                        /* Migrate old flags over */
1796                        update |= old->ce_flags & (CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1797                        invalidate_ce_path(old, o);
1798                }
1799
1800                if (submodule_from_ce(ce)) {
1801                        int ret = check_submodule_move_head(ce, oid_to_hex(&old->oid),
1802                                                            oid_to_hex(&ce->oid),
1803                                                            o);
1804                        if (ret)
1805                                return ret;
1806                }
1807        } else {
1808                /*
1809                 * Previously unmerged entry left as an existence
1810                 * marker by read_index_unmerged();
1811                 */
1812                invalidate_ce_path(old, o);
1813        }
1814
1815        do_add_entry(o, merge, update, CE_STAGEMASK);
1816        return 1;
1817}
1818
1819static int deleted_entry(const struct cache_entry *ce,
1820                         const struct cache_entry *old,
1821                         struct unpack_trees_options *o)
1822{
1823        /* Did it exist in the index? */
1824        if (!old) {
1825                if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1826                        return -1;
1827                return 0;
1828        }
1829        if (!(old->ce_flags & CE_CONFLICTED) && verify_uptodate(old, o))
1830                return -1;
1831        add_entry(o, ce, CE_REMOVE, 0);
1832        invalidate_ce_path(ce, o);
1833        return 1;
1834}
1835
1836static int keep_entry(const struct cache_entry *ce,
1837                      struct unpack_trees_options *o)
1838{
1839        add_entry(o, ce, 0, 0);
1840        return 1;
1841}
1842
1843#if DBRT_DEBUG
1844static void show_stage_entry(FILE *o,
1845                             const char *label, const struct cache_entry *ce)
1846{
1847        if (!ce)
1848                fprintf(o, "%s (missing)\n", label);
1849        else
1850                fprintf(o, "%s%06o %s %d\t%s\n",
1851                        label,
1852                        ce->ce_mode,
1853                        oid_to_hex(&ce->oid),
1854                        ce_stage(ce),
1855                        ce->name);
1856}
1857#endif
1858
1859int threeway_merge(const struct cache_entry * const *stages,
1860                   struct unpack_trees_options *o)
1861{
1862        const struct cache_entry *index;
1863        const struct cache_entry *head;
1864        const struct cache_entry *remote = stages[o->head_idx + 1];
1865        int count;
1866        int head_match = 0;
1867        int remote_match = 0;
1868
1869        int df_conflict_head = 0;
1870        int df_conflict_remote = 0;
1871
1872        int any_anc_missing = 0;
1873        int no_anc_exists = 1;
1874        int i;
1875
1876        for (i = 1; i < o->head_idx; i++) {
1877                if (!stages[i] || stages[i] == o->df_conflict_entry)
1878                        any_anc_missing = 1;
1879                else
1880                        no_anc_exists = 0;
1881        }
1882
1883        index = stages[0];
1884        head = stages[o->head_idx];
1885
1886        if (head == o->df_conflict_entry) {
1887                df_conflict_head = 1;
1888                head = NULL;
1889        }
1890
1891        if (remote == o->df_conflict_entry) {
1892                df_conflict_remote = 1;
1893                remote = NULL;
1894        }
1895
1896        /*
1897         * First, if there's a #16 situation, note that to prevent #13
1898         * and #14.
1899         */
1900        if (!same(remote, head)) {
1901                for (i = 1; i < o->head_idx; i++) {
1902                        if (same(stages[i], head)) {
1903                                head_match = i;
1904                        }
1905                        if (same(stages[i], remote)) {
1906                                remote_match = i;
1907                        }
1908                }
1909        }
1910
1911        /*
1912         * We start with cases where the index is allowed to match
1913         * something other than the head: #14(ALT) and #2ALT, where it
1914         * is permitted to match the result instead.
1915         */
1916        /* #14, #14ALT, #2ALT */
1917        if (remote && !df_conflict_head && head_match && !remote_match) {
1918                if (index && !same(index, remote) && !same(index, head))
1919                        return reject_merge(index, o);
1920                return merged_entry(remote, index, o);
1921        }
1922        /*
1923         * If we have an entry in the index cache, then we want to
1924         * make sure that it matches head.
1925         */
1926        if (index && !same(index, head))
1927                return reject_merge(index, o);
1928
1929        if (head) {
1930                /* #5ALT, #15 */
1931                if (same(head, remote))
1932                        return merged_entry(head, index, o);
1933                /* #13, #3ALT */
1934                if (!df_conflict_remote && remote_match && !head_match)
1935                        return merged_entry(head, index, o);
1936        }
1937
1938        /* #1 */
1939        if (!head && !remote && any_anc_missing)
1940                return 0;
1941
1942        /*
1943         * Under the "aggressive" rule, we resolve mostly trivial
1944         * cases that we historically had git-merge-one-file resolve.
1945         */
1946        if (o->aggressive) {
1947                int head_deleted = !head;
1948                int remote_deleted = !remote;
1949                const struct cache_entry *ce = NULL;
1950
1951                if (index)
1952                        ce = index;
1953                else if (head)
1954                        ce = head;
1955                else if (remote)
1956                        ce = remote;
1957                else {
1958                        for (i = 1; i < o->head_idx; i++) {
1959                                if (stages[i] && stages[i] != o->df_conflict_entry) {
1960                                        ce = stages[i];
1961                                        break;
1962                                }
1963                        }
1964                }
1965
1966                /*
1967                 * Deleted in both.
1968                 * Deleted in one and unchanged in the other.
1969                 */
1970                if ((head_deleted && remote_deleted) ||
1971                    (head_deleted && remote && remote_match) ||
1972                    (remote_deleted && head && head_match)) {
1973                        if (index)
1974                                return deleted_entry(index, index, o);
1975                        if (ce && !head_deleted) {
1976                                if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1977                                        return -1;
1978                        }
1979                        return 0;
1980                }
1981                /*
1982                 * Added in both, identically.
1983                 */
1984                if (no_anc_exists && head && remote && same(head, remote))
1985                        return merged_entry(head, index, o);
1986
1987        }
1988
1989        /* Below are "no merge" cases, which require that the index be
1990         * up-to-date to avoid the files getting overwritten with
1991         * conflict resolution files.
1992         */
1993        if (index) {
1994                if (verify_uptodate(index, o))
1995                        return -1;
1996        }
1997
1998        o->nontrivial_merge = 1;
1999
2000        /* #2, #3, #4, #6, #7, #9, #10, #11. */
2001        count = 0;
2002        if (!head_match || !remote_match) {
2003                for (i = 1; i < o->head_idx; i++) {
2004                        if (stages[i] && stages[i] != o->df_conflict_entry) {
2005                                keep_entry(stages[i], o);
2006                                count++;
2007                                break;
2008                        }
2009                }
2010        }
2011#if DBRT_DEBUG
2012        else {
2013                fprintf(stderr, "read-tree: warning #16 detected\n");
2014                show_stage_entry(stderr, "head   ", stages[head_match]);
2015                show_stage_entry(stderr, "remote ", stages[remote_match]);
2016        }
2017#endif
2018        if (head) { count += keep_entry(head, o); }
2019        if (remote) { count += keep_entry(remote, o); }
2020        return count;
2021}
2022
2023/*
2024 * Two-way merge.
2025 *
2026 * The rule is to "carry forward" what is in the index without losing
2027 * information across a "fast-forward", favoring a successful merge
2028 * over a merge failure when it makes sense.  For details of the
2029 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
2030 *
2031 */
2032int twoway_merge(const struct cache_entry * const *src,
2033                 struct unpack_trees_options *o)
2034{
2035        const struct cache_entry *current = src[0];
2036        const struct cache_entry *oldtree = src[1];
2037        const struct cache_entry *newtree = src[2];
2038
2039        if (o->merge_size != 2)
2040                return error("Cannot do a twoway merge of %d trees",
2041                             o->merge_size);
2042
2043        if (oldtree == o->df_conflict_entry)
2044                oldtree = NULL;
2045        if (newtree == o->df_conflict_entry)
2046                newtree = NULL;
2047
2048        if (current) {
2049                if (current->ce_flags & CE_CONFLICTED) {
2050                        if (same(oldtree, newtree) || o->reset) {
2051                                if (!newtree)
2052                                        return deleted_entry(current, current, o);
2053                                else
2054                                        return merged_entry(newtree, current, o);
2055                        }
2056                        return reject_merge(current, o);
2057                } else if ((!oldtree && !newtree) || /* 4 and 5 */
2058                         (!oldtree && newtree &&
2059                          same(current, newtree)) || /* 6 and 7 */
2060                         (oldtree && newtree &&
2061                          same(oldtree, newtree)) || /* 14 and 15 */
2062                         (oldtree && newtree &&
2063                          !same(oldtree, newtree) && /* 18 and 19 */
2064                          same(current, newtree))) {
2065                        return keep_entry(current, o);
2066                } else if (oldtree && !newtree && same(current, oldtree)) {
2067                        /* 10 or 11 */
2068                        return deleted_entry(oldtree, current, o);
2069                } else if (oldtree && newtree &&
2070                         same(current, oldtree) && !same(current, newtree)) {
2071                        /* 20 or 21 */
2072                        return merged_entry(newtree, current, o);
2073                } else
2074                        return reject_merge(current, o);
2075        }
2076        else if (newtree) {
2077                if (oldtree && !o->initial_checkout) {
2078                        /*
2079                         * deletion of the path was staged;
2080                         */
2081                        if (same(oldtree, newtree))
2082                                return 1;
2083                        return reject_merge(oldtree, o);
2084                }
2085                return merged_entry(newtree, current, o);
2086        }
2087        return deleted_entry(oldtree, current, o);
2088}
2089
2090/*
2091 * Bind merge.
2092 *
2093 * Keep the index entries at stage0, collapse stage1 but make sure
2094 * stage0 does not have anything there.
2095 */
2096int bind_merge(const struct cache_entry * const *src,
2097               struct unpack_trees_options *o)
2098{
2099        const struct cache_entry *old = src[0];
2100        const struct cache_entry *a = src[1];
2101
2102        if (o->merge_size != 1)
2103                return error("Cannot do a bind merge of %d trees",
2104                             o->merge_size);
2105        if (a && old)
2106                return o->gently ? -1 :
2107                        error(ERRORMSG(o, ERROR_BIND_OVERLAP),
2108                              super_prefixed(a->name),
2109                              super_prefixed(old->name));
2110        if (!a)
2111                return keep_entry(old, o);
2112        else
2113                return merged_entry(a, NULL, o);
2114}
2115
2116/*
2117 * One-way merge.
2118 *
2119 * The rule is:
2120 * - take the stat information from stage0, take the data from stage1
2121 */
2122int oneway_merge(const struct cache_entry * const *src,
2123                 struct unpack_trees_options *o)
2124{
2125        const struct cache_entry *old = src[0];
2126        const struct cache_entry *a = src[1];
2127
2128        if (o->merge_size != 1)
2129                return error("Cannot do a oneway merge of %d trees",
2130                             o->merge_size);
2131
2132        if (!a || a == o->df_conflict_entry)
2133                return deleted_entry(old, old, o);
2134
2135        if (old && same(old, a)) {
2136                int update = 0;
2137                if (o->reset && o->update && !ce_uptodate(old) && !ce_skip_worktree(old)) {
2138                        struct stat st;
2139                        if (lstat(old->name, &st) ||
2140                            ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
2141                                update |= CE_UPDATE;
2142                }
2143                add_entry(o, old, update, 0);
2144                return 0;
2145        }
2146        return merged_entry(a, old, o);
2147}