unpack-trees.con commit Merge branch 'jk/lock-ref-sha1-basic-return-errors' (3cdb0cb)
   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
  13/*
  14 * Error messages expected by scripts out of plumbing commands such as
  15 * read-tree.  Non-scripted Porcelain is not required to use these messages
  16 * and in fact are encouraged to reword them to better suit their particular
  17 * situation better.  See how "git checkout" and "git merge" replaces
  18 * them using setup_unpack_trees_porcelain(), for example.
  19 */
  20static const char *unpack_plumbing_errors[NB_UNPACK_TREES_ERROR_TYPES] = {
  21        /* ERROR_WOULD_OVERWRITE */
  22        "Entry '%s' would be overwritten by merge. Cannot merge.",
  23
  24        /* ERROR_NOT_UPTODATE_FILE */
  25        "Entry '%s' not uptodate. Cannot merge.",
  26
  27        /* ERROR_NOT_UPTODATE_DIR */
  28        "Updating '%s' would lose untracked files in it",
  29
  30        /* ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN */
  31        "Untracked working tree file '%s' would be overwritten by merge.",
  32
  33        /* ERROR_WOULD_LOSE_UNTRACKED_REMOVED */
  34        "Untracked working tree file '%s' would be removed by merge.",
  35
  36        /* ERROR_BIND_OVERLAP */
  37        "Entry '%s' overlaps with '%s'.  Cannot bind.",
  38
  39        /* ERROR_SPARSE_NOT_UPTODATE_FILE */
  40        "Entry '%s' not uptodate. Cannot update sparse checkout.",
  41
  42        /* ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN */
  43        "Working tree file '%s' would be overwritten by sparse checkout update.",
  44
  45        /* ERROR_WOULD_LOSE_ORPHANED_REMOVED */
  46        "Working tree file '%s' would be removed by sparse checkout update.",
  47};
  48
  49#define ERRORMSG(o,type) \
  50        ( ((o) && (o)->msgs[(type)]) \
  51          ? ((o)->msgs[(type)])      \
  52          : (unpack_plumbing_errors[(type)]) )
  53
  54void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
  55                                  const char *cmd)
  56{
  57        int i;
  58        const char **msgs = opts->msgs;
  59        const char *msg;
  60        const char *cmd2 = strcmp(cmd, "checkout") ? cmd : "switch branches";
  61
  62        if (advice_commit_before_merge)
  63                msg = "Your local changes to the following files would be overwritten by %s:\n%%s"
  64                        "Please, commit your changes or stash them before you can %s.";
  65        else
  66                msg = "Your local changes to the following files would be overwritten by %s:\n%%s";
  67        msgs[ERROR_WOULD_OVERWRITE] = msgs[ERROR_NOT_UPTODATE_FILE] =
  68                xstrfmt(msg, cmd, cmd2);
  69
  70        msgs[ERROR_NOT_UPTODATE_DIR] =
  71                "Updating the following directories would lose untracked files in it:\n%s";
  72
  73        if (advice_commit_before_merge)
  74                msg = "The following untracked working tree files would be %s by %s:\n%%s"
  75                        "Please move or remove them before you can %s.";
  76        else
  77                msg = "The following untracked working tree files would be %s by %s:\n%%s";
  78
  79        msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = xstrfmt(msg, "removed", cmd, cmd2);
  80        msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = xstrfmt(msg, "overwritten", cmd, cmd2);
  81
  82        /*
  83         * Special case: ERROR_BIND_OVERLAP refers to a pair of paths, we
  84         * cannot easily display it as a list.
  85         */
  86        msgs[ERROR_BIND_OVERLAP] = "Entry '%s' overlaps with '%s'.  Cannot bind.";
  87
  88        msgs[ERROR_SPARSE_NOT_UPTODATE_FILE] =
  89                "Cannot update sparse checkout: the following entries are not up-to-date:\n%s";
  90        msgs[ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN] =
  91                "The following Working tree files would be overwritten by sparse checkout update:\n%s";
  92        msgs[ERROR_WOULD_LOSE_ORPHANED_REMOVED] =
  93                "The following Working tree files would be removed by sparse checkout update:\n%s";
  94
  95        opts->show_all_errors = 1;
  96        /* rejected paths may not have a static buffer */
  97        for (i = 0; i < ARRAY_SIZE(opts->unpack_rejects); i++)
  98                opts->unpack_rejects[i].strdup_strings = 1;
  99}
 100
 101static int do_add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
 102                         unsigned int set, unsigned int clear)
 103{
 104        clear |= CE_HASHED;
 105
 106        if (set & CE_REMOVE)
 107                set |= CE_WT_REMOVE;
 108
 109        ce->ce_flags = (ce->ce_flags & ~clear) | set;
 110        return add_index_entry(&o->result, ce,
 111                               ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 112}
 113
 114static struct cache_entry *dup_entry(const struct cache_entry *ce)
 115{
 116        unsigned int size = ce_size(ce);
 117        struct cache_entry *new = xmalloc(size);
 118
 119        memcpy(new, ce, size);
 120        return new;
 121}
 122
 123static void add_entry(struct unpack_trees_options *o,
 124                      const struct cache_entry *ce,
 125                      unsigned int set, unsigned int clear)
 126{
 127        do_add_entry(o, dup_entry(ce), set, clear);
 128}
 129
 130/*
 131 * add error messages on path <path>
 132 * corresponding to the type <e> with the message <msg>
 133 * indicating if it should be display in porcelain or not
 134 */
 135static int add_rejected_path(struct unpack_trees_options *o,
 136                             enum unpack_trees_error_types e,
 137                             const char *path)
 138{
 139        if (!o->show_all_errors)
 140                return error(ERRORMSG(o, e), path);
 141
 142        /*
 143         * Otherwise, insert in a list for future display by
 144         * display_error_msgs()
 145         */
 146        string_list_append(&o->unpack_rejects[e], path);
 147        return -1;
 148}
 149
 150/*
 151 * display all the error messages stored in a nice way
 152 */
 153static void display_error_msgs(struct unpack_trees_options *o)
 154{
 155        int e, i;
 156        int something_displayed = 0;
 157        for (e = 0; e < NB_UNPACK_TREES_ERROR_TYPES; e++) {
 158                struct string_list *rejects = &o->unpack_rejects[e];
 159                if (rejects->nr > 0) {
 160                        struct strbuf path = STRBUF_INIT;
 161                        something_displayed = 1;
 162                        for (i = 0; i < rejects->nr; i++)
 163                                strbuf_addf(&path, "\t%s\n", rejects->items[i].string);
 164                        error(ERRORMSG(o, e), path.buf);
 165                        strbuf_release(&path);
 166                }
 167                string_list_clear(rejects, 0);
 168        }
 169        if (something_displayed)
 170                fprintf(stderr, "Aborting\n");
 171}
 172
 173/*
 174 * Unlink the last component and schedule the leading directories for
 175 * removal, such that empty directories get removed.
 176 */
 177static void unlink_entry(const struct cache_entry *ce)
 178{
 179        if (!check_leading_path(ce->name, ce_namelen(ce)))
 180                return;
 181        if (remove_or_warn(ce->ce_mode, ce->name))
 182                return;
 183        schedule_dir_for_removal(ce->name, ce_namelen(ce));
 184}
 185
 186static struct checkout state;
 187static int check_updates(struct unpack_trees_options *o)
 188{
 189        unsigned cnt = 0, total = 0;
 190        struct progress *progress = NULL;
 191        struct index_state *index = &o->result;
 192        int i;
 193        int errs = 0;
 194
 195        if (o->update && o->verbose_update) {
 196                for (total = cnt = 0; cnt < index->cache_nr; cnt++) {
 197                        const struct cache_entry *ce = index->cache[cnt];
 198                        if (ce->ce_flags & (CE_UPDATE | CE_WT_REMOVE))
 199                                total++;
 200                }
 201
 202                progress = start_progress_delay(_("Checking out files"),
 203                                                total, 50, 1);
 204                cnt = 0;
 205        }
 206
 207        if (o->update)
 208                git_attr_set_direction(GIT_ATTR_CHECKOUT, &o->result);
 209        for (i = 0; i < index->cache_nr; i++) {
 210                const struct cache_entry *ce = index->cache[i];
 211
 212                if (ce->ce_flags & CE_WT_REMOVE) {
 213                        display_progress(progress, ++cnt);
 214                        if (o->update && !o->dry_run)
 215                                unlink_entry(ce);
 216                        continue;
 217                }
 218        }
 219        remove_marked_cache_entries(&o->result);
 220        remove_scheduled_dirs();
 221
 222        for (i = 0; i < index->cache_nr; i++) {
 223                struct cache_entry *ce = index->cache[i];
 224
 225                if (ce->ce_flags & CE_UPDATE) {
 226                        display_progress(progress, ++cnt);
 227                        ce->ce_flags &= ~CE_UPDATE;
 228                        if (o->update && !o->dry_run) {
 229                                errs |= checkout_entry(ce, &state, NULL);
 230                        }
 231                }
 232        }
 233        stop_progress(&progress);
 234        if (o->update)
 235                git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
 236        return errs != 0;
 237}
 238
 239static int verify_uptodate_sparse(const struct cache_entry *ce,
 240                                  struct unpack_trees_options *o);
 241static int verify_absent_sparse(const struct cache_entry *ce,
 242                                enum unpack_trees_error_types,
 243                                struct unpack_trees_options *o);
 244
 245static int apply_sparse_checkout(struct index_state *istate,
 246                                 struct cache_entry *ce,
 247                                 struct unpack_trees_options *o)
 248{
 249        int was_skip_worktree = ce_skip_worktree(ce);
 250
 251        if (ce->ce_flags & CE_NEW_SKIP_WORKTREE)
 252                ce->ce_flags |= CE_SKIP_WORKTREE;
 253        else
 254                ce->ce_flags &= ~CE_SKIP_WORKTREE;
 255        if (was_skip_worktree != ce_skip_worktree(ce)) {
 256                ce->ce_flags |= CE_UPDATE_IN_BASE;
 257                istate->cache_changed |= CE_ENTRY_CHANGED;
 258        }
 259
 260        /*
 261         * if (!was_skip_worktree && !ce_skip_worktree()) {
 262         *      This is perfectly normal. Move on;
 263         * }
 264         */
 265
 266        /*
 267         * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
 268         * area as a result of ce_skip_worktree() shortcuts in
 269         * verify_absent() and verify_uptodate().
 270         * Make sure they don't modify worktree if they are already
 271         * outside checkout area
 272         */
 273        if (was_skip_worktree && ce_skip_worktree(ce)) {
 274                ce->ce_flags &= ~CE_UPDATE;
 275
 276                /*
 277                 * By default, when CE_REMOVE is on, CE_WT_REMOVE is also
 278                 * on to get that file removed from both index and worktree.
 279                 * If that file is already outside worktree area, don't
 280                 * bother remove it.
 281                 */
 282                if (ce->ce_flags & CE_REMOVE)
 283                        ce->ce_flags &= ~CE_WT_REMOVE;
 284        }
 285
 286        if (!was_skip_worktree && ce_skip_worktree(ce)) {
 287                /*
 288                 * If CE_UPDATE is set, verify_uptodate() must be called already
 289                 * also stat info may have lost after merged_entry() so calling
 290                 * verify_uptodate() again may fail
 291                 */
 292                if (!(ce->ce_flags & CE_UPDATE) && verify_uptodate_sparse(ce, o))
 293                        return -1;
 294                ce->ce_flags |= CE_WT_REMOVE;
 295        }
 296        if (was_skip_worktree && !ce_skip_worktree(ce)) {
 297                if (verify_absent_sparse(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o))
 298                        return -1;
 299                ce->ce_flags |= CE_UPDATE;
 300        }
 301        return 0;
 302}
 303
 304static inline int call_unpack_fn(const struct cache_entry * const *src,
 305                                 struct unpack_trees_options *o)
 306{
 307        int ret = o->fn(src, o);
 308        if (ret > 0)
 309                ret = 0;
 310        return ret;
 311}
 312
 313static void mark_ce_used(struct cache_entry *ce, struct unpack_trees_options *o)
 314{
 315        ce->ce_flags |= CE_UNPACKED;
 316
 317        if (o->cache_bottom < o->src_index->cache_nr &&
 318            o->src_index->cache[o->cache_bottom] == ce) {
 319                int bottom = o->cache_bottom;
 320                while (bottom < o->src_index->cache_nr &&
 321                       o->src_index->cache[bottom]->ce_flags & CE_UNPACKED)
 322                        bottom++;
 323                o->cache_bottom = bottom;
 324        }
 325}
 326
 327static void mark_all_ce_unused(struct index_state *index)
 328{
 329        int i;
 330        for (i = 0; i < index->cache_nr; i++)
 331                index->cache[i]->ce_flags &= ~(CE_UNPACKED | CE_ADDED | CE_NEW_SKIP_WORKTREE);
 332}
 333
 334static int locate_in_src_index(const struct cache_entry *ce,
 335                               struct unpack_trees_options *o)
 336{
 337        struct index_state *index = o->src_index;
 338        int len = ce_namelen(ce);
 339        int pos = index_name_pos(index, ce->name, len);
 340        if (pos < 0)
 341                pos = -1 - pos;
 342        return pos;
 343}
 344
 345/*
 346 * We call unpack_index_entry() with an unmerged cache entry
 347 * only in diff-index, and it wants a single callback.  Skip
 348 * the other unmerged entry with the same name.
 349 */
 350static void mark_ce_used_same_name(struct cache_entry *ce,
 351                                   struct unpack_trees_options *o)
 352{
 353        struct index_state *index = o->src_index;
 354        int len = ce_namelen(ce);
 355        int pos;
 356
 357        for (pos = locate_in_src_index(ce, o); pos < index->cache_nr; pos++) {
 358                struct cache_entry *next = index->cache[pos];
 359                if (len != ce_namelen(next) ||
 360                    memcmp(ce->name, next->name, len))
 361                        break;
 362                mark_ce_used(next, o);
 363        }
 364}
 365
 366static struct cache_entry *next_cache_entry(struct unpack_trees_options *o)
 367{
 368        const struct index_state *index = o->src_index;
 369        int pos = o->cache_bottom;
 370
 371        while (pos < index->cache_nr) {
 372                struct cache_entry *ce = index->cache[pos];
 373                if (!(ce->ce_flags & CE_UNPACKED))
 374                        return ce;
 375                pos++;
 376        }
 377        return NULL;
 378}
 379
 380static void add_same_unmerged(const struct cache_entry *ce,
 381                              struct unpack_trees_options *o)
 382{
 383        struct index_state *index = o->src_index;
 384        int len = ce_namelen(ce);
 385        int pos = index_name_pos(index, ce->name, len);
 386
 387        if (0 <= pos)
 388                die("programming error in a caller of mark_ce_used_same_name");
 389        for (pos = -pos - 1; pos < index->cache_nr; pos++) {
 390                struct cache_entry *next = index->cache[pos];
 391                if (len != ce_namelen(next) ||
 392                    memcmp(ce->name, next->name, len))
 393                        break;
 394                add_entry(o, next, 0, 0);
 395                mark_ce_used(next, o);
 396        }
 397}
 398
 399static int unpack_index_entry(struct cache_entry *ce,
 400                              struct unpack_trees_options *o)
 401{
 402        const struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 403        int ret;
 404
 405        src[0] = ce;
 406
 407        mark_ce_used(ce, o);
 408        if (ce_stage(ce)) {
 409                if (o->skip_unmerged) {
 410                        add_entry(o, ce, 0, 0);
 411                        return 0;
 412                }
 413        }
 414        ret = call_unpack_fn(src, o);
 415        if (ce_stage(ce))
 416                mark_ce_used_same_name(ce, o);
 417        return ret;
 418}
 419
 420static int find_cache_pos(struct traverse_info *, const struct name_entry *);
 421
 422static void restore_cache_bottom(struct traverse_info *info, int bottom)
 423{
 424        struct unpack_trees_options *o = info->data;
 425
 426        if (o->diff_index_cached)
 427                return;
 428        o->cache_bottom = bottom;
 429}
 430
 431static int switch_cache_bottom(struct traverse_info *info)
 432{
 433        struct unpack_trees_options *o = info->data;
 434        int ret, pos;
 435
 436        if (o->diff_index_cached)
 437                return 0;
 438        ret = o->cache_bottom;
 439        pos = find_cache_pos(info->prev, &info->name);
 440
 441        if (pos < -1)
 442                o->cache_bottom = -2 - pos;
 443        else if (pos < 0)
 444                o->cache_bottom = o->src_index->cache_nr;
 445        return ret;
 446}
 447
 448static int traverse_trees_recursive(int n, unsigned long dirmask,
 449                                    unsigned long df_conflicts,
 450                                    struct name_entry *names,
 451                                    struct traverse_info *info)
 452{
 453        int i, ret, bottom;
 454        struct tree_desc t[MAX_UNPACK_TREES];
 455        void *buf[MAX_UNPACK_TREES];
 456        struct traverse_info newinfo;
 457        struct name_entry *p;
 458
 459        p = names;
 460        while (!p->mode)
 461                p++;
 462
 463        newinfo = *info;
 464        newinfo.prev = info;
 465        newinfo.pathspec = info->pathspec;
 466        newinfo.name = *p;
 467        newinfo.pathlen += tree_entry_len(p) + 1;
 468        newinfo.df_conflicts |= df_conflicts;
 469
 470        for (i = 0; i < n; i++, dirmask >>= 1) {
 471                const unsigned char *sha1 = NULL;
 472                if (dirmask & 1)
 473                        sha1 = names[i].sha1;
 474                buf[i] = fill_tree_descriptor(t+i, sha1);
 475        }
 476
 477        bottom = switch_cache_bottom(&newinfo);
 478        ret = traverse_trees(n, t, &newinfo);
 479        restore_cache_bottom(&newinfo, bottom);
 480
 481        for (i = 0; i < n; i++)
 482                free(buf[i]);
 483
 484        return ret;
 485}
 486
 487/*
 488 * Compare the traverse-path to the cache entry without actually
 489 * having to generate the textual representation of the traverse
 490 * path.
 491 *
 492 * NOTE! This *only* compares up to the size of the traverse path
 493 * itself - the caller needs to do the final check for the cache
 494 * entry having more data at the end!
 495 */
 496static int do_compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 497{
 498        int len, pathlen, ce_len;
 499        const char *ce_name;
 500
 501        if (info->prev) {
 502                int cmp = do_compare_entry(ce, info->prev, &info->name);
 503                if (cmp)
 504                        return cmp;
 505        }
 506        pathlen = info->pathlen;
 507        ce_len = ce_namelen(ce);
 508
 509        /* If ce_len < pathlen then we must have previously hit "name == directory" entry */
 510        if (ce_len < pathlen)
 511                return -1;
 512
 513        ce_len -= pathlen;
 514        ce_name = ce->name + pathlen;
 515
 516        len = tree_entry_len(n);
 517        return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 518}
 519
 520static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 521{
 522        int cmp = do_compare_entry(ce, info, n);
 523        if (cmp)
 524                return cmp;
 525
 526        /*
 527         * Even if the beginning compared identically, the ce should
 528         * compare as bigger than a directory leading up to it!
 529         */
 530        return ce_namelen(ce) > traverse_path_len(info, n);
 531}
 532
 533static int ce_in_traverse_path(const struct cache_entry *ce,
 534                               const struct traverse_info *info)
 535{
 536        if (!info->prev)
 537                return 1;
 538        if (do_compare_entry(ce, info->prev, &info->name))
 539                return 0;
 540        /*
 541         * If ce (blob) is the same name as the path (which is a tree
 542         * we will be descending into), it won't be inside it.
 543         */
 544        return (info->pathlen < ce_namelen(ce));
 545}
 546
 547static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
 548{
 549        int len = traverse_path_len(info, n);
 550        struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
 551
 552        ce->ce_mode = create_ce_mode(n->mode);
 553        ce->ce_flags = create_ce_flags(stage);
 554        ce->ce_namelen = len;
 555        hashcpy(ce->sha1, n->sha1);
 556        make_traverse_path(ce->name, info, n);
 557
 558        return ce;
 559}
 560
 561static int unpack_nondirectories(int n, unsigned long mask,
 562                                 unsigned long dirmask,
 563                                 struct cache_entry **src,
 564                                 const struct name_entry *names,
 565                                 const struct traverse_info *info)
 566{
 567        int i;
 568        struct unpack_trees_options *o = info->data;
 569        unsigned long conflicts = info->df_conflicts | dirmask;
 570
 571        /* Do we have *only* directories? Nothing to do */
 572        if (mask == dirmask && !src[0])
 573                return 0;
 574
 575        /*
 576         * Ok, we've filled in up to any potential index entry in src[0],
 577         * now do the rest.
 578         */
 579        for (i = 0; i < n; i++) {
 580                int stage;
 581                unsigned int bit = 1ul << i;
 582                if (conflicts & bit) {
 583                        src[i + o->merge] = o->df_conflict_entry;
 584                        continue;
 585                }
 586                if (!(mask & bit))
 587                        continue;
 588                if (!o->merge)
 589                        stage = 0;
 590                else if (i + 1 < o->head_idx)
 591                        stage = 1;
 592                else if (i + 1 > o->head_idx)
 593                        stage = 3;
 594                else
 595                        stage = 2;
 596                src[i + o->merge] = create_ce_entry(info, names + i, stage);
 597        }
 598
 599        if (o->merge) {
 600                int rc = call_unpack_fn((const struct cache_entry * const *)src,
 601                                        o);
 602                for (i = 0; i < n; i++) {
 603                        struct cache_entry *ce = src[i + o->merge];
 604                        if (ce != o->df_conflict_entry)
 605                                free(ce);
 606                }
 607                return rc;
 608        }
 609
 610        for (i = 0; i < n; i++)
 611                if (src[i] && src[i] != o->df_conflict_entry)
 612                        if (do_add_entry(o, src[i], 0, 0))
 613                                return -1;
 614
 615        return 0;
 616}
 617
 618static int unpack_failed(struct unpack_trees_options *o, const char *message)
 619{
 620        discard_index(&o->result);
 621        if (!o->gently && !o->exiting_early) {
 622                if (message)
 623                        return error("%s", message);
 624                return -1;
 625        }
 626        return -1;
 627}
 628
 629/*
 630 * The tree traversal is looking at name p.  If we have a matching entry,
 631 * return it.  If name p is a directory in the index, do not return
 632 * anything, as we will want to match it when the traversal descends into
 633 * the directory.
 634 */
 635static int find_cache_pos(struct traverse_info *info,
 636                          const struct name_entry *p)
 637{
 638        int pos;
 639        struct unpack_trees_options *o = info->data;
 640        struct index_state *index = o->src_index;
 641        int pfxlen = info->pathlen;
 642        int p_len = tree_entry_len(p);
 643
 644        for (pos = o->cache_bottom; pos < index->cache_nr; pos++) {
 645                const struct cache_entry *ce = index->cache[pos];
 646                const char *ce_name, *ce_slash;
 647                int cmp, ce_len;
 648
 649                if (ce->ce_flags & CE_UNPACKED) {
 650                        /*
 651                         * cache_bottom entry is already unpacked, so
 652                         * we can never match it; don't check it
 653                         * again.
 654                         */
 655                        if (pos == o->cache_bottom)
 656                                ++o->cache_bottom;
 657                        continue;
 658                }
 659                if (!ce_in_traverse_path(ce, info))
 660                        continue;
 661                ce_name = ce->name + pfxlen;
 662                ce_slash = strchr(ce_name, '/');
 663                if (ce_slash)
 664                        ce_len = ce_slash - ce_name;
 665                else
 666                        ce_len = ce_namelen(ce) - pfxlen;
 667                cmp = name_compare(p->path, p_len, ce_name, ce_len);
 668                /*
 669                 * Exact match; if we have a directory we need to
 670                 * delay returning it.
 671                 */
 672                if (!cmp)
 673                        return ce_slash ? -2 - pos : pos;
 674                if (0 < cmp)
 675                        continue; /* keep looking */
 676                /*
 677                 * ce_name sorts after p->path; could it be that we
 678                 * have files under p->path directory in the index?
 679                 * E.g.  ce_name == "t-i", and p->path == "t"; we may
 680                 * have "t/a" in the index.
 681                 */
 682                if (p_len < ce_len && !memcmp(ce_name, p->path, p_len) &&
 683                    ce_name[p_len] < '/')
 684                        continue; /* keep looking */
 685                break;
 686        }
 687        return -1;
 688}
 689
 690static struct cache_entry *find_cache_entry(struct traverse_info *info,
 691                                            const struct name_entry *p)
 692{
 693        int pos = find_cache_pos(info, p);
 694        struct unpack_trees_options *o = info->data;
 695
 696        if (0 <= pos)
 697                return o->src_index->cache[pos];
 698        else
 699                return NULL;
 700}
 701
 702static void debug_path(struct traverse_info *info)
 703{
 704        if (info->prev) {
 705                debug_path(info->prev);
 706                if (*info->prev->name.path)
 707                        putchar('/');
 708        }
 709        printf("%s", info->name.path);
 710}
 711
 712static void debug_name_entry(int i, struct name_entry *n)
 713{
 714        printf("ent#%d %06o %s\n", i,
 715               n->path ? n->mode : 0,
 716               n->path ? n->path : "(missing)");
 717}
 718
 719static void debug_unpack_callback(int n,
 720                                  unsigned long mask,
 721                                  unsigned long dirmask,
 722                                  struct name_entry *names,
 723                                  struct traverse_info *info)
 724{
 725        int i;
 726        printf("* unpack mask %lu, dirmask %lu, cnt %d ",
 727               mask, dirmask, n);
 728        debug_path(info);
 729        putchar('\n');
 730        for (i = 0; i < n; i++)
 731                debug_name_entry(i, names + i);
 732}
 733
 734static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
 735{
 736        struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 737        struct unpack_trees_options *o = info->data;
 738        const struct name_entry *p = names;
 739
 740        /* Find first entry with a real name (we could use "mask" too) */
 741        while (!p->mode)
 742                p++;
 743
 744        if (o->debug_unpack)
 745                debug_unpack_callback(n, mask, dirmask, names, info);
 746
 747        /* Are we supposed to look at the index too? */
 748        if (o->merge) {
 749                while (1) {
 750                        int cmp;
 751                        struct cache_entry *ce;
 752
 753                        if (o->diff_index_cached)
 754                                ce = next_cache_entry(o);
 755                        else
 756                                ce = find_cache_entry(info, p);
 757
 758                        if (!ce)
 759                                break;
 760                        cmp = compare_entry(ce, info, p);
 761                        if (cmp < 0) {
 762                                if (unpack_index_entry(ce, o) < 0)
 763                                        return unpack_failed(o, NULL);
 764                                continue;
 765                        }
 766                        if (!cmp) {
 767                                if (ce_stage(ce)) {
 768                                        /*
 769                                         * If we skip unmerged index
 770                                         * entries, we'll skip this
 771                                         * entry *and* the tree
 772                                         * entries associated with it!
 773                                         */
 774                                        if (o->skip_unmerged) {
 775                                                add_same_unmerged(ce, o);
 776                                                return mask;
 777                                        }
 778                                }
 779                                src[0] = ce;
 780                        }
 781                        break;
 782                }
 783        }
 784
 785        if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
 786                return -1;
 787
 788        if (o->merge && src[0]) {
 789                if (ce_stage(src[0]))
 790                        mark_ce_used_same_name(src[0], o);
 791                else
 792                        mark_ce_used(src[0], o);
 793        }
 794
 795        /* Now handle any directories.. */
 796        if (dirmask) {
 797                /* special case: "diff-index --cached" looking at a tree */
 798                if (o->diff_index_cached &&
 799                    n == 1 && dirmask == 1 && S_ISDIR(names->mode)) {
 800                        int matches;
 801                        matches = cache_tree_matches_traversal(o->src_index->cache_tree,
 802                                                               names, info);
 803                        /*
 804                         * Everything under the name matches; skip the
 805                         * entire hierarchy.  diff_index_cached codepath
 806                         * special cases D/F conflicts in such a way that
 807                         * it does not do any look-ahead, so this is safe.
 808                         */
 809                        if (matches) {
 810                                o->cache_bottom += matches;
 811                                return mask;
 812                        }
 813                }
 814
 815                if (traverse_trees_recursive(n, dirmask, mask & ~dirmask,
 816                                             names, info) < 0)
 817                        return -1;
 818                return mask;
 819        }
 820
 821        return mask;
 822}
 823
 824static int clear_ce_flags_1(struct cache_entry **cache, int nr,
 825                            struct strbuf *prefix,
 826                            int select_mask, int clear_mask,
 827                            struct exclude_list *el, int defval);
 828
 829/* Whole directory matching */
 830static int clear_ce_flags_dir(struct cache_entry **cache, int nr,
 831                              struct strbuf *prefix,
 832                              char *basename,
 833                              int select_mask, int clear_mask,
 834                              struct exclude_list *el, int defval)
 835{
 836        struct cache_entry **cache_end;
 837        int dtype = DT_DIR;
 838        int ret = is_excluded_from_list(prefix->buf, prefix->len,
 839                                        basename, &dtype, el);
 840        int rc;
 841
 842        strbuf_addch(prefix, '/');
 843
 844        /* If undecided, use matching result of parent dir in defval */
 845        if (ret < 0)
 846                ret = defval;
 847
 848        for (cache_end = cache; cache_end != cache + nr; cache_end++) {
 849                struct cache_entry *ce = *cache_end;
 850                if (strncmp(ce->name, prefix->buf, prefix->len))
 851                        break;
 852        }
 853
 854        /*
 855         * TODO: check el, if there are no patterns that may conflict
 856         * with ret (iow, we know in advance the incl/excl
 857         * decision for the entire directory), clear flag here without
 858         * calling clear_ce_flags_1(). That function will call
 859         * the expensive is_excluded_from_list() on every entry.
 860         */
 861        rc = clear_ce_flags_1(cache, cache_end - cache,
 862                              prefix,
 863                              select_mask, clear_mask,
 864                              el, ret);
 865        strbuf_setlen(prefix, prefix->len - 1);
 866        return rc;
 867}
 868
 869/*
 870 * Traverse the index, find every entry that matches according to
 871 * o->el. Do "ce_flags &= ~clear_mask" on those entries. Return the
 872 * number of traversed entries.
 873 *
 874 * If select_mask is non-zero, only entries whose ce_flags has on of
 875 * those bits enabled are traversed.
 876 *
 877 * cache        : pointer to an index entry
 878 * prefix_len   : an offset to its path
 879 *
 880 * The current path ("prefix") including the trailing '/' is
 881 *   cache[0]->name[0..(prefix_len-1)]
 882 * Top level path has prefix_len zero.
 883 */
 884static int clear_ce_flags_1(struct cache_entry **cache, int nr,
 885                            struct strbuf *prefix,
 886                            int select_mask, int clear_mask,
 887                            struct exclude_list *el, int defval)
 888{
 889        struct cache_entry **cache_end = cache + nr;
 890
 891        /*
 892         * Process all entries that have the given prefix and meet
 893         * select_mask condition
 894         */
 895        while(cache != cache_end) {
 896                struct cache_entry *ce = *cache;
 897                const char *name, *slash;
 898                int len, dtype, ret;
 899
 900                if (select_mask && !(ce->ce_flags & select_mask)) {
 901                        cache++;
 902                        continue;
 903                }
 904
 905                if (prefix->len && strncmp(ce->name, prefix->buf, prefix->len))
 906                        break;
 907
 908                name = ce->name + prefix->len;
 909                slash = strchr(name, '/');
 910
 911                /* If it's a directory, try whole directory match first */
 912                if (slash) {
 913                        int processed;
 914
 915                        len = slash - name;
 916                        strbuf_add(prefix, name, len);
 917
 918                        processed = clear_ce_flags_dir(cache, cache_end - cache,
 919                                                       prefix,
 920                                                       prefix->buf + prefix->len - len,
 921                                                       select_mask, clear_mask,
 922                                                       el, defval);
 923
 924                        /* clear_c_f_dir eats a whole dir already? */
 925                        if (processed) {
 926                                cache += processed;
 927                                strbuf_setlen(prefix, prefix->len - len);
 928                                continue;
 929                        }
 930
 931                        strbuf_addch(prefix, '/');
 932                        cache += clear_ce_flags_1(cache, cache_end - cache,
 933                                                  prefix,
 934                                                  select_mask, clear_mask, el, defval);
 935                        strbuf_setlen(prefix, prefix->len - len - 1);
 936                        continue;
 937                }
 938
 939                /* Non-directory */
 940                dtype = ce_to_dtype(ce);
 941                ret = is_excluded_from_list(ce->name, ce_namelen(ce),
 942                                            name, &dtype, el);
 943                if (ret < 0)
 944                        ret = defval;
 945                if (ret > 0)
 946                        ce->ce_flags &= ~clear_mask;
 947                cache++;
 948        }
 949        return nr - (cache_end - cache);
 950}
 951
 952static int clear_ce_flags(struct cache_entry **cache, int nr,
 953                            int select_mask, int clear_mask,
 954                            struct exclude_list *el)
 955{
 956        static struct strbuf prefix = STRBUF_INIT;
 957
 958        strbuf_reset(&prefix);
 959
 960        return clear_ce_flags_1(cache, nr,
 961                                &prefix,
 962                                select_mask, clear_mask,
 963                                el, 0);
 964}
 965
 966/*
 967 * Set/Clear CE_NEW_SKIP_WORKTREE according to $GIT_DIR/info/sparse-checkout
 968 */
 969static void mark_new_skip_worktree(struct exclude_list *el,
 970                                   struct index_state *the_index,
 971                                   int select_flag, int skip_wt_flag)
 972{
 973        int i;
 974
 975        /*
 976         * 1. Pretend the narrowest worktree: only unmerged entries
 977         * are checked out
 978         */
 979        for (i = 0; i < the_index->cache_nr; i++) {
 980                struct cache_entry *ce = the_index->cache[i];
 981
 982                if (select_flag && !(ce->ce_flags & select_flag))
 983                        continue;
 984
 985                if (!ce_stage(ce))
 986                        ce->ce_flags |= skip_wt_flag;
 987                else
 988                        ce->ce_flags &= ~skip_wt_flag;
 989        }
 990
 991        /*
 992         * 2. Widen worktree according to sparse-checkout file.
 993         * Matched entries will have skip_wt_flag cleared (i.e. "in")
 994         */
 995        clear_ce_flags(the_index->cache, the_index->cache_nr,
 996                       select_flag, skip_wt_flag, el);
 997}
 998
 999static int verify_absent(const struct cache_entry *,
1000                         enum unpack_trees_error_types,
1001                         struct unpack_trees_options *);
1002/*
1003 * N-way merge "len" trees.  Returns 0 on success, -1 on failure to manipulate the
1004 * resulting index, -2 on failure to reflect the changes to the work tree.
1005 *
1006 * CE_ADDED, CE_UNPACKED and CE_NEW_SKIP_WORKTREE are used internally
1007 */
1008int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
1009{
1010        int i, ret;
1011        static struct cache_entry *dfc;
1012        struct exclude_list el;
1013
1014        if (len > MAX_UNPACK_TREES)
1015                die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
1016        memset(&state, 0, sizeof(state));
1017        state.base_dir = "";
1018        state.force = 1;
1019        state.quiet = 1;
1020        state.refresh_cache = 1;
1021        state.istate = &o->result;
1022
1023        memset(&el, 0, sizeof(el));
1024        if (!core_apply_sparse_checkout || !o->update)
1025                o->skip_sparse_checkout = 1;
1026        if (!o->skip_sparse_checkout) {
1027                if (add_excludes_from_file_to_list(git_path("info/sparse-checkout"), "", 0, &el, 0) < 0)
1028                        o->skip_sparse_checkout = 1;
1029                else
1030                        o->el = &el;
1031        }
1032
1033        memset(&o->result, 0, sizeof(o->result));
1034        o->result.initialized = 1;
1035        o->result.timestamp.sec = o->src_index->timestamp.sec;
1036        o->result.timestamp.nsec = o->src_index->timestamp.nsec;
1037        o->result.version = o->src_index->version;
1038        o->result.split_index = o->src_index->split_index;
1039        if (o->result.split_index)
1040                o->result.split_index->refcount++;
1041        hashcpy(o->result.sha1, o->src_index->sha1);
1042        o->merge_size = len;
1043        mark_all_ce_unused(o->src_index);
1044
1045        /*
1046         * Sparse checkout loop #1: set NEW_SKIP_WORKTREE on existing entries
1047         */
1048        if (!o->skip_sparse_checkout)
1049                mark_new_skip_worktree(o->el, o->src_index, 0, CE_NEW_SKIP_WORKTREE);
1050
1051        if (!dfc)
1052                dfc = xcalloc(1, cache_entry_size(0));
1053        o->df_conflict_entry = dfc;
1054
1055        if (len) {
1056                const char *prefix = o->prefix ? o->prefix : "";
1057                struct traverse_info info;
1058
1059                setup_traverse_info(&info, prefix);
1060                info.fn = unpack_callback;
1061                info.data = o;
1062                info.show_all_errors = o->show_all_errors;
1063                info.pathspec = o->pathspec;
1064
1065                if (o->prefix) {
1066                        /*
1067                         * Unpack existing index entries that sort before the
1068                         * prefix the tree is spliced into.  Note that o->merge
1069                         * is always true in this case.
1070                         */
1071                        while (1) {
1072                                struct cache_entry *ce = next_cache_entry(o);
1073                                if (!ce)
1074                                        break;
1075                                if (ce_in_traverse_path(ce, &info))
1076                                        break;
1077                                if (unpack_index_entry(ce, o) < 0)
1078                                        goto return_failed;
1079                        }
1080                }
1081
1082                if (traverse_trees(len, t, &info) < 0)
1083                        goto return_failed;
1084        }
1085
1086        /* Any left-over entries in the index? */
1087        if (o->merge) {
1088                while (1) {
1089                        struct cache_entry *ce = next_cache_entry(o);
1090                        if (!ce)
1091                                break;
1092                        if (unpack_index_entry(ce, o) < 0)
1093                                goto return_failed;
1094                }
1095        }
1096        mark_all_ce_unused(o->src_index);
1097
1098        if (o->trivial_merges_only && o->nontrivial_merge) {
1099                ret = unpack_failed(o, "Merge requires file-level merging");
1100                goto done;
1101        }
1102
1103        if (!o->skip_sparse_checkout) {
1104                int empty_worktree = 1;
1105
1106                /*
1107                 * Sparse checkout loop #2: set NEW_SKIP_WORKTREE on entries not in loop #1
1108                 * If the will have NEW_SKIP_WORKTREE, also set CE_SKIP_WORKTREE
1109                 * so apply_sparse_checkout() won't attempt to remove it from worktree
1110                 */
1111                mark_new_skip_worktree(o->el, &o->result, CE_ADDED, CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1112
1113                ret = 0;
1114                for (i = 0; i < o->result.cache_nr; i++) {
1115                        struct cache_entry *ce = o->result.cache[i];
1116
1117                        /*
1118                         * Entries marked with CE_ADDED in merged_entry() do not have
1119                         * verify_absent() check (the check is effectively disabled
1120                         * because CE_NEW_SKIP_WORKTREE is set unconditionally).
1121                         *
1122                         * Do the real check now because we have had
1123                         * correct CE_NEW_SKIP_WORKTREE
1124                         */
1125                        if (ce->ce_flags & CE_ADDED &&
1126                            verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1127                                if (!o->show_all_errors)
1128                                        goto return_failed;
1129                                ret = -1;
1130                        }
1131
1132                        if (apply_sparse_checkout(&o->result, ce, o)) {
1133                                if (!o->show_all_errors)
1134                                        goto return_failed;
1135                                ret = -1;
1136                        }
1137                        if (!ce_skip_worktree(ce))
1138                                empty_worktree = 0;
1139
1140                }
1141                if (ret < 0)
1142                        goto return_failed;
1143                /*
1144                 * Sparse checkout is meant to narrow down checkout area
1145                 * but it does not make sense to narrow down to empty working
1146                 * tree. This is usually a mistake in sparse checkout rules.
1147                 * Do not allow users to do that.
1148                 */
1149                if (o->result.cache_nr && empty_worktree) {
1150                        ret = unpack_failed(o, "Sparse checkout leaves no entry on working directory");
1151                        goto done;
1152                }
1153        }
1154
1155        o->src_index = NULL;
1156        ret = check_updates(o) ? (-2) : 0;
1157        if (o->dst_index) {
1158                discard_index(o->dst_index);
1159                *o->dst_index = o->result;
1160        } else {
1161                discard_index(&o->result);
1162        }
1163
1164done:
1165        clear_exclude_list(&el);
1166        return ret;
1167
1168return_failed:
1169        if (o->show_all_errors)
1170                display_error_msgs(o);
1171        mark_all_ce_unused(o->src_index);
1172        ret = unpack_failed(o, NULL);
1173        if (o->exiting_early)
1174                ret = 0;
1175        goto done;
1176}
1177
1178/* Here come the merge functions */
1179
1180static int reject_merge(const struct cache_entry *ce,
1181                        struct unpack_trees_options *o)
1182{
1183        return o->gently ? -1 :
1184                add_rejected_path(o, ERROR_WOULD_OVERWRITE, ce->name);
1185}
1186
1187static int same(const struct cache_entry *a, const struct cache_entry *b)
1188{
1189        if (!!a != !!b)
1190                return 0;
1191        if (!a && !b)
1192                return 1;
1193        if ((a->ce_flags | b->ce_flags) & CE_CONFLICTED)
1194                return 0;
1195        return a->ce_mode == b->ce_mode &&
1196               !hashcmp(a->sha1, b->sha1);
1197}
1198
1199
1200/*
1201 * When a CE gets turned into an unmerged entry, we
1202 * want it to be up-to-date
1203 */
1204static int verify_uptodate_1(const struct cache_entry *ce,
1205                             struct unpack_trees_options *o,
1206                             enum unpack_trees_error_types error_type)
1207{
1208        struct stat st;
1209
1210        if (o->index_only)
1211                return 0;
1212
1213        /*
1214         * CE_VALID and CE_SKIP_WORKTREE cheat, we better check again
1215         * if this entry is truly up-to-date because this file may be
1216         * overwritten.
1217         */
1218        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
1219                ; /* keep checking */
1220        else if (o->reset || ce_uptodate(ce))
1221                return 0;
1222
1223        if (!lstat(ce->name, &st)) {
1224                int flags = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE;
1225                unsigned changed = ie_match_stat(o->src_index, ce, &st, flags);
1226                if (!changed)
1227                        return 0;
1228                /*
1229                 * NEEDSWORK: the current default policy is to allow
1230                 * submodule to be out of sync wrt the superproject
1231                 * index.  This needs to be tightened later for
1232                 * submodules that are marked to be automatically
1233                 * checked out.
1234                 */
1235                if (S_ISGITLINK(ce->ce_mode))
1236                        return 0;
1237                errno = 0;
1238        }
1239        if (errno == ENOENT)
1240                return 0;
1241        return o->gently ? -1 :
1242                add_rejected_path(o, error_type, ce->name);
1243}
1244
1245static int verify_uptodate(const struct cache_entry *ce,
1246                           struct unpack_trees_options *o)
1247{
1248        if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1249                return 0;
1250        return verify_uptodate_1(ce, o, ERROR_NOT_UPTODATE_FILE);
1251}
1252
1253static int verify_uptodate_sparse(const struct cache_entry *ce,
1254                                  struct unpack_trees_options *o)
1255{
1256        return verify_uptodate_1(ce, o, ERROR_SPARSE_NOT_UPTODATE_FILE);
1257}
1258
1259static void invalidate_ce_path(const struct cache_entry *ce,
1260                               struct unpack_trees_options *o)
1261{
1262        if (ce)
1263                cache_tree_invalidate_path(o->src_index, ce->name);
1264}
1265
1266/*
1267 * Check that checking out ce->sha1 in subdir ce->name is not
1268 * going to overwrite any working files.
1269 *
1270 * Currently, git does not checkout subprojects during a superproject
1271 * checkout, so it is not going to overwrite anything.
1272 */
1273static int verify_clean_submodule(const struct cache_entry *ce,
1274                                  enum unpack_trees_error_types error_type,
1275                                  struct unpack_trees_options *o)
1276{
1277        return 0;
1278}
1279
1280static int verify_clean_subdirectory(const struct cache_entry *ce,
1281                                     enum unpack_trees_error_types error_type,
1282                                     struct unpack_trees_options *o)
1283{
1284        /*
1285         * we are about to extract "ce->name"; we would not want to lose
1286         * anything in the existing directory there.
1287         */
1288        int namelen;
1289        int i;
1290        struct dir_struct d;
1291        char *pathbuf;
1292        int cnt = 0;
1293        unsigned char sha1[20];
1294
1295        if (S_ISGITLINK(ce->ce_mode) &&
1296            resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
1297                /* If we are not going to update the submodule, then
1298                 * we don't care.
1299                 */
1300                if (!hashcmp(sha1, ce->sha1))
1301                        return 0;
1302                return verify_clean_submodule(ce, error_type, o);
1303        }
1304
1305        /*
1306         * First let's make sure we do not have a local modification
1307         * in that directory.
1308         */
1309        namelen = ce_namelen(ce);
1310        for (i = locate_in_src_index(ce, o);
1311             i < o->src_index->cache_nr;
1312             i++) {
1313                struct cache_entry *ce2 = o->src_index->cache[i];
1314                int len = ce_namelen(ce2);
1315                if (len < namelen ||
1316                    strncmp(ce->name, ce2->name, namelen) ||
1317                    ce2->name[namelen] != '/')
1318                        break;
1319                /*
1320                 * ce2->name is an entry in the subdirectory to be
1321                 * removed.
1322                 */
1323                if (!ce_stage(ce2)) {
1324                        if (verify_uptodate(ce2, o))
1325                                return -1;
1326                        add_entry(o, ce2, CE_REMOVE, 0);
1327                        mark_ce_used(ce2, o);
1328                }
1329                cnt++;
1330        }
1331
1332        /*
1333         * Then we need to make sure that we do not lose a locally
1334         * present file that is not ignored.
1335         */
1336        pathbuf = xmalloc(namelen + 2);
1337        memcpy(pathbuf, ce->name, namelen);
1338        strcpy(pathbuf+namelen, "/");
1339
1340        memset(&d, 0, sizeof(d));
1341        if (o->dir)
1342                d.exclude_per_dir = o->dir->exclude_per_dir;
1343        i = read_directory(&d, pathbuf, namelen+1, NULL);
1344        if (i)
1345                return o->gently ? -1 :
1346                        add_rejected_path(o, ERROR_NOT_UPTODATE_DIR, ce->name);
1347        free(pathbuf);
1348        return cnt;
1349}
1350
1351/*
1352 * This gets called when there was no index entry for the tree entry 'dst',
1353 * but we found a file in the working tree that 'lstat()' said was fine,
1354 * and we're on a case-insensitive filesystem.
1355 *
1356 * See if we can find a case-insensitive match in the index that also
1357 * matches the stat information, and assume it's that other file!
1358 */
1359static int icase_exists(struct unpack_trees_options *o, const char *name, int len, struct stat *st)
1360{
1361        const struct cache_entry *src;
1362
1363        src = index_file_exists(o->src_index, name, len, 1);
1364        return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
1365}
1366
1367static int check_ok_to_remove(const char *name, int len, int dtype,
1368                              const struct cache_entry *ce, struct stat *st,
1369                              enum unpack_trees_error_types error_type,
1370                              struct unpack_trees_options *o)
1371{
1372        const struct cache_entry *result;
1373
1374        /*
1375         * It may be that the 'lstat()' succeeded even though
1376         * target 'ce' was absent, because there is an old
1377         * entry that is different only in case..
1378         *
1379         * Ignore that lstat() if it matches.
1380         */
1381        if (ignore_case && icase_exists(o, name, len, st))
1382                return 0;
1383
1384        if (o->dir &&
1385            is_excluded(o->dir, name, &dtype))
1386                /*
1387                 * ce->name is explicitly excluded, so it is Ok to
1388                 * overwrite it.
1389                 */
1390                return 0;
1391        if (S_ISDIR(st->st_mode)) {
1392                /*
1393                 * We are checking out path "foo" and
1394                 * found "foo/." in the working tree.
1395                 * This is tricky -- if we have modified
1396                 * files that are in "foo/" we would lose
1397                 * them.
1398                 */
1399                if (verify_clean_subdirectory(ce, error_type, o) < 0)
1400                        return -1;
1401                return 0;
1402        }
1403
1404        /*
1405         * The previous round may already have decided to
1406         * delete this path, which is in a subdirectory that
1407         * is being replaced with a blob.
1408         */
1409        result = index_file_exists(&o->result, name, len, 0);
1410        if (result) {
1411                if (result->ce_flags & CE_REMOVE)
1412                        return 0;
1413        }
1414
1415        return o->gently ? -1 :
1416                add_rejected_path(o, error_type, name);
1417}
1418
1419/*
1420 * We do not want to remove or overwrite a working tree file that
1421 * is not tracked, unless it is ignored.
1422 */
1423static int verify_absent_1(const struct cache_entry *ce,
1424                           enum unpack_trees_error_types error_type,
1425                           struct unpack_trees_options *o)
1426{
1427        int len;
1428        struct stat st;
1429
1430        if (o->index_only || o->reset || !o->update)
1431                return 0;
1432
1433        len = check_leading_path(ce->name, ce_namelen(ce));
1434        if (!len)
1435                return 0;
1436        else if (len > 0) {
1437                char path[PATH_MAX + 1];
1438                memcpy(path, ce->name, len);
1439                path[len] = 0;
1440                if (lstat(path, &st))
1441                        return error("cannot stat '%s': %s", path,
1442                                        strerror(errno));
1443
1444                return check_ok_to_remove(path, len, DT_UNKNOWN, NULL, &st,
1445                                error_type, o);
1446        } else if (lstat(ce->name, &st)) {
1447                if (errno != ENOENT)
1448                        return error("cannot stat '%s': %s", ce->name,
1449                                     strerror(errno));
1450                return 0;
1451        } else {
1452                return check_ok_to_remove(ce->name, ce_namelen(ce),
1453                                          ce_to_dtype(ce), ce, &st,
1454                                          error_type, o);
1455        }
1456}
1457
1458static int verify_absent(const struct cache_entry *ce,
1459                         enum unpack_trees_error_types error_type,
1460                         struct unpack_trees_options *o)
1461{
1462        if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1463                return 0;
1464        return verify_absent_1(ce, error_type, o);
1465}
1466
1467static int verify_absent_sparse(const struct cache_entry *ce,
1468                                enum unpack_trees_error_types error_type,
1469                                struct unpack_trees_options *o)
1470{
1471        enum unpack_trees_error_types orphaned_error = error_type;
1472        if (orphaned_error == ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN)
1473                orphaned_error = ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN;
1474
1475        return verify_absent_1(ce, orphaned_error, o);
1476}
1477
1478static int merged_entry(const struct cache_entry *ce,
1479                        const struct cache_entry *old,
1480                        struct unpack_trees_options *o)
1481{
1482        int update = CE_UPDATE;
1483        struct cache_entry *merge = dup_entry(ce);
1484
1485        if (!old) {
1486                /*
1487                 * New index entries. In sparse checkout, the following
1488                 * verify_absent() will be delayed until after
1489                 * traverse_trees() finishes in unpack_trees(), then:
1490                 *
1491                 *  - CE_NEW_SKIP_WORKTREE will be computed correctly
1492                 *  - verify_absent() be called again, this time with
1493                 *    correct CE_NEW_SKIP_WORKTREE
1494                 *
1495                 * verify_absent() call here does nothing in sparse
1496                 * checkout (i.e. o->skip_sparse_checkout == 0)
1497                 */
1498                update |= CE_ADDED;
1499                merge->ce_flags |= CE_NEW_SKIP_WORKTREE;
1500
1501                if (verify_absent(merge,
1502                                  ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1503                        free(merge);
1504                        return -1;
1505                }
1506                invalidate_ce_path(merge, o);
1507        } else if (!(old->ce_flags & CE_CONFLICTED)) {
1508                /*
1509                 * See if we can re-use the old CE directly?
1510                 * That way we get the uptodate stat info.
1511                 *
1512                 * This also removes the UPDATE flag on a match; otherwise
1513                 * we will end up overwriting local changes in the work tree.
1514                 */
1515                if (same(old, merge)) {
1516                        copy_cache_entry(merge, old);
1517                        update = 0;
1518                } else {
1519                        if (verify_uptodate(old, o)) {
1520                                free(merge);
1521                                return -1;
1522                        }
1523                        /* Migrate old flags over */
1524                        update |= old->ce_flags & (CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1525                        invalidate_ce_path(old, o);
1526                }
1527        } else {
1528                /*
1529                 * Previously unmerged entry left as an existence
1530                 * marker by read_index_unmerged();
1531                 */
1532                invalidate_ce_path(old, o);
1533        }
1534
1535        do_add_entry(o, merge, update, CE_STAGEMASK);
1536        return 1;
1537}
1538
1539static int deleted_entry(const struct cache_entry *ce,
1540                         const struct cache_entry *old,
1541                         struct unpack_trees_options *o)
1542{
1543        /* Did it exist in the index? */
1544        if (!old) {
1545                if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1546                        return -1;
1547                return 0;
1548        }
1549        if (!(old->ce_flags & CE_CONFLICTED) && verify_uptodate(old, o))
1550                return -1;
1551        add_entry(o, ce, CE_REMOVE, 0);
1552        invalidate_ce_path(ce, o);
1553        return 1;
1554}
1555
1556static int keep_entry(const struct cache_entry *ce,
1557                      struct unpack_trees_options *o)
1558{
1559        add_entry(o, ce, 0, 0);
1560        return 1;
1561}
1562
1563#if DBRT_DEBUG
1564static void show_stage_entry(FILE *o,
1565                             const char *label, const struct cache_entry *ce)
1566{
1567        if (!ce)
1568                fprintf(o, "%s (missing)\n", label);
1569        else
1570                fprintf(o, "%s%06o %s %d\t%s\n",
1571                        label,
1572                        ce->ce_mode,
1573                        sha1_to_hex(ce->sha1),
1574                        ce_stage(ce),
1575                        ce->name);
1576}
1577#endif
1578
1579int threeway_merge(const struct cache_entry * const *stages,
1580                   struct unpack_trees_options *o)
1581{
1582        const struct cache_entry *index;
1583        const struct cache_entry *head;
1584        const struct cache_entry *remote = stages[o->head_idx + 1];
1585        int count;
1586        int head_match = 0;
1587        int remote_match = 0;
1588
1589        int df_conflict_head = 0;
1590        int df_conflict_remote = 0;
1591
1592        int any_anc_missing = 0;
1593        int no_anc_exists = 1;
1594        int i;
1595
1596        for (i = 1; i < o->head_idx; i++) {
1597                if (!stages[i] || stages[i] == o->df_conflict_entry)
1598                        any_anc_missing = 1;
1599                else
1600                        no_anc_exists = 0;
1601        }
1602
1603        index = stages[0];
1604        head = stages[o->head_idx];
1605
1606        if (head == o->df_conflict_entry) {
1607                df_conflict_head = 1;
1608                head = NULL;
1609        }
1610
1611        if (remote == o->df_conflict_entry) {
1612                df_conflict_remote = 1;
1613                remote = NULL;
1614        }
1615
1616        /*
1617         * First, if there's a #16 situation, note that to prevent #13
1618         * and #14.
1619         */
1620        if (!same(remote, head)) {
1621                for (i = 1; i < o->head_idx; i++) {
1622                        if (same(stages[i], head)) {
1623                                head_match = i;
1624                        }
1625                        if (same(stages[i], remote)) {
1626                                remote_match = i;
1627                        }
1628                }
1629        }
1630
1631        /*
1632         * We start with cases where the index is allowed to match
1633         * something other than the head: #14(ALT) and #2ALT, where it
1634         * is permitted to match the result instead.
1635         */
1636        /* #14, #14ALT, #2ALT */
1637        if (remote && !df_conflict_head && head_match && !remote_match) {
1638                if (index && !same(index, remote) && !same(index, head))
1639                        return reject_merge(index, o);
1640                return merged_entry(remote, index, o);
1641        }
1642        /*
1643         * If we have an entry in the index cache, then we want to
1644         * make sure that it matches head.
1645         */
1646        if (index && !same(index, head))
1647                return reject_merge(index, o);
1648
1649        if (head) {
1650                /* #5ALT, #15 */
1651                if (same(head, remote))
1652                        return merged_entry(head, index, o);
1653                /* #13, #3ALT */
1654                if (!df_conflict_remote && remote_match && !head_match)
1655                        return merged_entry(head, index, o);
1656        }
1657
1658        /* #1 */
1659        if (!head && !remote && any_anc_missing)
1660                return 0;
1661
1662        /*
1663         * Under the "aggressive" rule, we resolve mostly trivial
1664         * cases that we historically had git-merge-one-file resolve.
1665         */
1666        if (o->aggressive) {
1667                int head_deleted = !head;
1668                int remote_deleted = !remote;
1669                const struct cache_entry *ce = NULL;
1670
1671                if (index)
1672                        ce = index;
1673                else if (head)
1674                        ce = head;
1675                else if (remote)
1676                        ce = remote;
1677                else {
1678                        for (i = 1; i < o->head_idx; i++) {
1679                                if (stages[i] && stages[i] != o->df_conflict_entry) {
1680                                        ce = stages[i];
1681                                        break;
1682                                }
1683                        }
1684                }
1685
1686                /*
1687                 * Deleted in both.
1688                 * Deleted in one and unchanged in the other.
1689                 */
1690                if ((head_deleted && remote_deleted) ||
1691                    (head_deleted && remote && remote_match) ||
1692                    (remote_deleted && head && head_match)) {
1693                        if (index)
1694                                return deleted_entry(index, index, o);
1695                        if (ce && !head_deleted) {
1696                                if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1697                                        return -1;
1698                        }
1699                        return 0;
1700                }
1701                /*
1702                 * Added in both, identically.
1703                 */
1704                if (no_anc_exists && head && remote && same(head, remote))
1705                        return merged_entry(head, index, o);
1706
1707        }
1708
1709        /* Below are "no merge" cases, which require that the index be
1710         * up-to-date to avoid the files getting overwritten with
1711         * conflict resolution files.
1712         */
1713        if (index) {
1714                if (verify_uptodate(index, o))
1715                        return -1;
1716        }
1717
1718        o->nontrivial_merge = 1;
1719
1720        /* #2, #3, #4, #6, #7, #9, #10, #11. */
1721        count = 0;
1722        if (!head_match || !remote_match) {
1723                for (i = 1; i < o->head_idx; i++) {
1724                        if (stages[i] && stages[i] != o->df_conflict_entry) {
1725                                keep_entry(stages[i], o);
1726                                count++;
1727                                break;
1728                        }
1729                }
1730        }
1731#if DBRT_DEBUG
1732        else {
1733                fprintf(stderr, "read-tree: warning #16 detected\n");
1734                show_stage_entry(stderr, "head   ", stages[head_match]);
1735                show_stage_entry(stderr, "remote ", stages[remote_match]);
1736        }
1737#endif
1738        if (head) { count += keep_entry(head, o); }
1739        if (remote) { count += keep_entry(remote, o); }
1740        return count;
1741}
1742
1743/*
1744 * Two-way merge.
1745 *
1746 * The rule is to "carry forward" what is in the index without losing
1747 * information across a "fast-forward", favoring a successful merge
1748 * over a merge failure when it makes sense.  For details of the
1749 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
1750 *
1751 */
1752int twoway_merge(const struct cache_entry * const *src,
1753                 struct unpack_trees_options *o)
1754{
1755        const struct cache_entry *current = src[0];
1756        const struct cache_entry *oldtree = src[1];
1757        const struct cache_entry *newtree = src[2];
1758
1759        if (o->merge_size != 2)
1760                return error("Cannot do a twoway merge of %d trees",
1761                             o->merge_size);
1762
1763        if (oldtree == o->df_conflict_entry)
1764                oldtree = NULL;
1765        if (newtree == o->df_conflict_entry)
1766                newtree = NULL;
1767
1768        if (current) {
1769                if (current->ce_flags & CE_CONFLICTED) {
1770                        if (same(oldtree, newtree) || o->reset) {
1771                                if (!newtree)
1772                                        return deleted_entry(current, current, o);
1773                                else
1774                                        return merged_entry(newtree, current, o);
1775                        }
1776                        return reject_merge(current, o);
1777                } else if ((!oldtree && !newtree) || /* 4 and 5 */
1778                         (!oldtree && newtree &&
1779                          same(current, newtree)) || /* 6 and 7 */
1780                         (oldtree && newtree &&
1781                          same(oldtree, newtree)) || /* 14 and 15 */
1782                         (oldtree && newtree &&
1783                          !same(oldtree, newtree) && /* 18 and 19 */
1784                          same(current, newtree))) {
1785                        return keep_entry(current, o);
1786                } else if (oldtree && !newtree && same(current, oldtree)) {
1787                        /* 10 or 11 */
1788                        return deleted_entry(oldtree, current, o);
1789                } else if (oldtree && newtree &&
1790                         same(current, oldtree) && !same(current, newtree)) {
1791                        /* 20 or 21 */
1792                        return merged_entry(newtree, current, o);
1793                } else
1794                        return reject_merge(current, o);
1795        }
1796        else if (newtree) {
1797                if (oldtree && !o->initial_checkout) {
1798                        /*
1799                         * deletion of the path was staged;
1800                         */
1801                        if (same(oldtree, newtree))
1802                                return 1;
1803                        return reject_merge(oldtree, o);
1804                }
1805                return merged_entry(newtree, current, o);
1806        }
1807        return deleted_entry(oldtree, current, o);
1808}
1809
1810/*
1811 * Bind merge.
1812 *
1813 * Keep the index entries at stage0, collapse stage1 but make sure
1814 * stage0 does not have anything there.
1815 */
1816int bind_merge(const struct cache_entry * const *src,
1817               struct unpack_trees_options *o)
1818{
1819        const struct cache_entry *old = src[0];
1820        const struct cache_entry *a = src[1];
1821
1822        if (o->merge_size != 1)
1823                return error("Cannot do a bind merge of %d trees",
1824                             o->merge_size);
1825        if (a && old)
1826                return o->gently ? -1 :
1827                        error(ERRORMSG(o, ERROR_BIND_OVERLAP), a->name, old->name);
1828        if (!a)
1829                return keep_entry(old, o);
1830        else
1831                return merged_entry(a, NULL, o);
1832}
1833
1834/*
1835 * One-way merge.
1836 *
1837 * The rule is:
1838 * - take the stat information from stage0, take the data from stage1
1839 */
1840int oneway_merge(const struct cache_entry * const *src,
1841                 struct unpack_trees_options *o)
1842{
1843        const struct cache_entry *old = src[0];
1844        const struct cache_entry *a = src[1];
1845
1846        if (o->merge_size != 1)
1847                return error("Cannot do a oneway merge of %d trees",
1848                             o->merge_size);
1849
1850        if (!a || a == o->df_conflict_entry)
1851                return deleted_entry(old, old, o);
1852
1853        if (old && same(old, a)) {
1854                int update = 0;
1855                if (o->reset && o->update && !ce_uptodate(old) && !ce_skip_worktree(old)) {
1856                        struct stat st;
1857                        if (lstat(old->name, &st) ||
1858                            ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
1859                                update |= CE_UPDATE;
1860                }
1861                add_entry(o, old, update, 0);
1862                return 0;
1863        }
1864        return merged_entry(a, old, o);
1865}