unpack-trees.con commit Merge branch 'jk/merge-base-fork-point-without-reflog' (92657ea)
   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
  14/*
  15 * Error messages expected by scripts out of plumbing commands such as
  16 * read-tree.  Non-scripted Porcelain is not required to use these messages
  17 * and in fact are encouraged to reword them to better suit their particular
  18 * situation better.  See how "git checkout" and "git merge" replaces
  19 * them using setup_unpack_trees_porcelain(), for example.
  20 */
  21static const char *unpack_plumbing_errors[NB_UNPACK_TREES_ERROR_TYPES] = {
  22        /* ERROR_WOULD_OVERWRITE */
  23        "Entry '%s' would be overwritten by merge. Cannot merge.",
  24
  25        /* ERROR_NOT_UPTODATE_FILE */
  26        "Entry '%s' not uptodate. Cannot merge.",
  27
  28        /* ERROR_NOT_UPTODATE_DIR */
  29        "Updating '%s' would lose untracked files in it",
  30
  31        /* ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN */
  32        "Untracked working tree file '%s' would be overwritten by merge.",
  33
  34        /* ERROR_WOULD_LOSE_UNTRACKED_REMOVED */
  35        "Untracked working tree file '%s' would be removed by merge.",
  36
  37        /* ERROR_BIND_OVERLAP */
  38        "Entry '%s' overlaps with '%s'.  Cannot bind.",
  39
  40        /* ERROR_SPARSE_NOT_UPTODATE_FILE */
  41        "Entry '%s' not uptodate. Cannot update sparse checkout.",
  42
  43        /* ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN */
  44        "Working tree file '%s' would be overwritten by sparse checkout update.",
  45
  46        /* ERROR_WOULD_LOSE_ORPHANED_REMOVED */
  47        "Working tree file '%s' would be removed by sparse checkout update.",
  48};
  49
  50#define ERRORMSG(o,type) \
  51        ( ((o) && (o)->msgs[(type)]) \
  52          ? ((o)->msgs[(type)])      \
  53          : (unpack_plumbing_errors[(type)]) )
  54
  55void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
  56                                  const char *cmd)
  57{
  58        int i;
  59        const char **msgs = opts->msgs;
  60        const char *msg;
  61
  62        if (!strcmp(cmd, "checkout"))
  63                msg = advice_commit_before_merge
  64                      ? _("Your local changes to the following files would be overwritten by checkout:\n%%s"
  65                          "Please commit your changes or stash them before you switch branches.")
  66                      : _("Your local changes to the following files would be overwritten by checkout:\n%%s");
  67        else if (!strcmp(cmd, "merge"))
  68                msg = advice_commit_before_merge
  69                      ? _("Your local changes to the following files would be overwritten by merge:\n%%s"
  70                          "Please commit your changes or stash them before you merge.")
  71                      : _("Your local changes to the following files would be overwritten by merge:\n%%s");
  72        else
  73                msg = advice_commit_before_merge
  74                      ? _("Your local changes to the following files would be overwritten by %s:\n%%s"
  75                          "Please commit your changes or stash them before you %s.")
  76                      : _("Your local changes to the following files would be overwritten by %s:\n%%s");
  77        msgs[ERROR_WOULD_OVERWRITE] = msgs[ERROR_NOT_UPTODATE_FILE] =
  78                xstrfmt(msg, cmd, cmd);
  79
  80        msgs[ERROR_NOT_UPTODATE_DIR] =
  81                _("Updating the following directories would lose untracked files in it:\n%s");
  82
  83        if (!strcmp(cmd, "checkout"))
  84                msg = advice_commit_before_merge
  85                      ? _("The following untracked working tree files would be removed by checkout:\n%%s"
  86                          "Please move or remove them before you switch branches.")
  87                      : _("The following untracked working tree files would be removed by checkout:\n%%s");
  88        else if (!strcmp(cmd, "merge"))
  89                msg = advice_commit_before_merge
  90                      ? _("The following untracked working tree files would be removed by merge:\n%%s"
  91                          "Please move or remove them before you merge.")
  92                      : _("The following untracked working tree files would be removed by merge:\n%%s");
  93        else
  94                msg = advice_commit_before_merge
  95                      ? _("The following untracked working tree files would be removed by %s:\n%%s"
  96                          "Please move or remove them before you %s.")
  97                      : _("The following untracked working tree files would be removed by %s:\n%%s");
  98        msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = xstrfmt(msg, cmd, cmd);
  99
 100        if (!strcmp(cmd, "checkout"))
 101                msg = advice_commit_before_merge
 102                      ? _("The following untracked working tree files would be overwritten by checkout:\n%%s"
 103                          "Please move or remove them before you switch branches.")
 104                      : _("The following untracked working tree files would be overwritten by checkout:\n%%s");
 105        else if (!strcmp(cmd, "merge"))
 106                msg = advice_commit_before_merge
 107                      ? _("The following untracked working tree files would be overwritten by merge:\n%%s"
 108                          "Please move or remove them before you merge.")
 109                      : _("The following untracked working tree files would be overwritten by merge:\n%%s");
 110        else
 111                msg = advice_commit_before_merge
 112                      ? _("The following untracked working tree files would be overwritten by %s:\n%%s"
 113                          "Please move or remove them before you %s.")
 114                      : _("The following untracked working tree files would be overwritten by %s:\n%%s");
 115        msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = xstrfmt(msg, cmd, cmd);
 116
 117        /*
 118         * Special case: ERROR_BIND_OVERLAP refers to a pair of paths, we
 119         * cannot easily display it as a list.
 120         */
 121        msgs[ERROR_BIND_OVERLAP] = _("Entry '%s' overlaps with '%s'.  Cannot bind.");
 122
 123        msgs[ERROR_SPARSE_NOT_UPTODATE_FILE] =
 124                _("Cannot update sparse checkout: the following entries are not up-to-date:\n%s");
 125        msgs[ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN] =
 126                _("The following working tree files would be overwritten by sparse checkout update:\n%s");
 127        msgs[ERROR_WOULD_LOSE_ORPHANED_REMOVED] =
 128                _("The following working tree files would be removed by sparse checkout update:\n%s");
 129
 130        opts->show_all_errors = 1;
 131        /* rejected paths may not have a static buffer */
 132        for (i = 0; i < ARRAY_SIZE(opts->unpack_rejects); i++)
 133                opts->unpack_rejects[i].strdup_strings = 1;
 134}
 135
 136static int do_add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
 137                         unsigned int set, unsigned int clear)
 138{
 139        clear |= CE_HASHED;
 140
 141        if (set & CE_REMOVE)
 142                set |= CE_WT_REMOVE;
 143
 144        ce->ce_flags = (ce->ce_flags & ~clear) | set;
 145        return add_index_entry(&o->result, ce,
 146                               ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 147}
 148
 149static struct cache_entry *dup_entry(const struct cache_entry *ce)
 150{
 151        unsigned int size = ce_size(ce);
 152        struct cache_entry *new = xmalloc(size);
 153
 154        memcpy(new, ce, size);
 155        return new;
 156}
 157
 158static void add_entry(struct unpack_trees_options *o,
 159                      const struct cache_entry *ce,
 160                      unsigned int set, unsigned int clear)
 161{
 162        do_add_entry(o, dup_entry(ce), set, clear);
 163}
 164
 165/*
 166 * add error messages on path <path>
 167 * corresponding to the type <e> with the message <msg>
 168 * indicating if it should be display in porcelain or not
 169 */
 170static int add_rejected_path(struct unpack_trees_options *o,
 171                             enum unpack_trees_error_types e,
 172                             const char *path)
 173{
 174        if (!o->show_all_errors)
 175                return error(ERRORMSG(o, e), path);
 176
 177        /*
 178         * Otherwise, insert in a list for future display by
 179         * display_error_msgs()
 180         */
 181        string_list_append(&o->unpack_rejects[e], path);
 182        return -1;
 183}
 184
 185/*
 186 * display all the error messages stored in a nice way
 187 */
 188static void display_error_msgs(struct unpack_trees_options *o)
 189{
 190        int e, i;
 191        int something_displayed = 0;
 192        for (e = 0; e < NB_UNPACK_TREES_ERROR_TYPES; e++) {
 193                struct string_list *rejects = &o->unpack_rejects[e];
 194                if (rejects->nr > 0) {
 195                        struct strbuf path = STRBUF_INIT;
 196                        something_displayed = 1;
 197                        for (i = 0; i < rejects->nr; i++)
 198                                strbuf_addf(&path, "\t%s\n", rejects->items[i].string);
 199                        error(ERRORMSG(o, e), path.buf);
 200                        strbuf_release(&path);
 201                }
 202                string_list_clear(rejects, 0);
 203        }
 204        if (something_displayed)
 205                fprintf(stderr, _("Aborting\n"));
 206}
 207
 208/*
 209 * Unlink the last component and schedule the leading directories for
 210 * removal, such that empty directories get removed.
 211 */
 212static void unlink_entry(const struct cache_entry *ce)
 213{
 214        if (!check_leading_path(ce->name, ce_namelen(ce)))
 215                return;
 216        if (remove_or_warn(ce->ce_mode, ce->name))
 217                return;
 218        schedule_dir_for_removal(ce->name, ce_namelen(ce));
 219}
 220
 221static int check_updates(struct unpack_trees_options *o,
 222                         const struct checkout *state)
 223{
 224        unsigned cnt = 0, total = 0;
 225        struct progress *progress = NULL;
 226        struct index_state *index = &o->result;
 227        int i;
 228        int errs = 0;
 229
 230        if (o->update && o->verbose_update) {
 231                for (total = cnt = 0; cnt < index->cache_nr; cnt++) {
 232                        const struct cache_entry *ce = index->cache[cnt];
 233                        if (ce->ce_flags & (CE_UPDATE | CE_WT_REMOVE))
 234                                total++;
 235                }
 236
 237                progress = start_progress_delay(_("Checking out files"),
 238                                                total, 50, 1);
 239                cnt = 0;
 240        }
 241
 242        if (o->update)
 243                git_attr_set_direction(GIT_ATTR_CHECKOUT, &o->result);
 244        for (i = 0; i < index->cache_nr; i++) {
 245                const struct cache_entry *ce = index->cache[i];
 246
 247                if (ce->ce_flags & CE_WT_REMOVE) {
 248                        display_progress(progress, ++cnt);
 249                        if (o->update && !o->dry_run)
 250                                unlink_entry(ce);
 251                        continue;
 252                }
 253        }
 254        remove_marked_cache_entries(&o->result);
 255        remove_scheduled_dirs();
 256
 257        for (i = 0; i < index->cache_nr; i++) {
 258                struct cache_entry *ce = index->cache[i];
 259
 260                if (ce->ce_flags & CE_UPDATE) {
 261                        if (ce->ce_flags & CE_WT_REMOVE)
 262                                die("BUG: both update and delete flags are set on %s",
 263                                    ce->name);
 264                        display_progress(progress, ++cnt);
 265                        ce->ce_flags &= ~CE_UPDATE;
 266                        if (o->update && !o->dry_run) {
 267                                errs |= checkout_entry(ce, state, NULL);
 268                        }
 269                }
 270        }
 271        stop_progress(&progress);
 272        if (o->update)
 273                git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
 274        return errs != 0;
 275}
 276
 277static int verify_uptodate_sparse(const struct cache_entry *ce,
 278                                  struct unpack_trees_options *o);
 279static int verify_absent_sparse(const struct cache_entry *ce,
 280                                enum unpack_trees_error_types,
 281                                struct unpack_trees_options *o);
 282
 283static int apply_sparse_checkout(struct index_state *istate,
 284                                 struct cache_entry *ce,
 285                                 struct unpack_trees_options *o)
 286{
 287        int was_skip_worktree = ce_skip_worktree(ce);
 288
 289        if (ce->ce_flags & CE_NEW_SKIP_WORKTREE)
 290                ce->ce_flags |= CE_SKIP_WORKTREE;
 291        else
 292                ce->ce_flags &= ~CE_SKIP_WORKTREE;
 293        if (was_skip_worktree != ce_skip_worktree(ce)) {
 294                ce->ce_flags |= CE_UPDATE_IN_BASE;
 295                istate->cache_changed |= CE_ENTRY_CHANGED;
 296        }
 297
 298        /*
 299         * if (!was_skip_worktree && !ce_skip_worktree()) {
 300         *      This is perfectly normal. Move on;
 301         * }
 302         */
 303
 304        /*
 305         * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
 306         * area as a result of ce_skip_worktree() shortcuts in
 307         * verify_absent() and verify_uptodate().
 308         * Make sure they don't modify worktree if they are already
 309         * outside checkout area
 310         */
 311        if (was_skip_worktree && ce_skip_worktree(ce)) {
 312                ce->ce_flags &= ~CE_UPDATE;
 313
 314                /*
 315                 * By default, when CE_REMOVE is on, CE_WT_REMOVE is also
 316                 * on to get that file removed from both index and worktree.
 317                 * If that file is already outside worktree area, don't
 318                 * bother remove it.
 319                 */
 320                if (ce->ce_flags & CE_REMOVE)
 321                        ce->ce_flags &= ~CE_WT_REMOVE;
 322        }
 323
 324        if (!was_skip_worktree && ce_skip_worktree(ce)) {
 325                /*
 326                 * If CE_UPDATE is set, verify_uptodate() must be called already
 327                 * also stat info may have lost after merged_entry() so calling
 328                 * verify_uptodate() again may fail
 329                 */
 330                if (!(ce->ce_flags & CE_UPDATE) && verify_uptodate_sparse(ce, o))
 331                        return -1;
 332                ce->ce_flags |= CE_WT_REMOVE;
 333                ce->ce_flags &= ~CE_UPDATE;
 334        }
 335        if (was_skip_worktree && !ce_skip_worktree(ce)) {
 336                if (verify_absent_sparse(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o))
 337                        return -1;
 338                ce->ce_flags |= CE_UPDATE;
 339        }
 340        return 0;
 341}
 342
 343static inline int call_unpack_fn(const struct cache_entry * const *src,
 344                                 struct unpack_trees_options *o)
 345{
 346        int ret = o->fn(src, o);
 347        if (ret > 0)
 348                ret = 0;
 349        return ret;
 350}
 351
 352static void mark_ce_used(struct cache_entry *ce, struct unpack_trees_options *o)
 353{
 354        ce->ce_flags |= CE_UNPACKED;
 355
 356        if (o->cache_bottom < o->src_index->cache_nr &&
 357            o->src_index->cache[o->cache_bottom] == ce) {
 358                int bottom = o->cache_bottom;
 359                while (bottom < o->src_index->cache_nr &&
 360                       o->src_index->cache[bottom]->ce_flags & CE_UNPACKED)
 361                        bottom++;
 362                o->cache_bottom = bottom;
 363        }
 364}
 365
 366static void mark_all_ce_unused(struct index_state *index)
 367{
 368        int i;
 369        for (i = 0; i < index->cache_nr; i++)
 370                index->cache[i]->ce_flags &= ~(CE_UNPACKED | CE_ADDED | CE_NEW_SKIP_WORKTREE);
 371}
 372
 373static int locate_in_src_index(const struct cache_entry *ce,
 374                               struct unpack_trees_options *o)
 375{
 376        struct index_state *index = o->src_index;
 377        int len = ce_namelen(ce);
 378        int pos = index_name_pos(index, ce->name, len);
 379        if (pos < 0)
 380                pos = -1 - pos;
 381        return pos;
 382}
 383
 384/*
 385 * We call unpack_index_entry() with an unmerged cache entry
 386 * only in diff-index, and it wants a single callback.  Skip
 387 * the other unmerged entry with the same name.
 388 */
 389static void mark_ce_used_same_name(struct cache_entry *ce,
 390                                   struct unpack_trees_options *o)
 391{
 392        struct index_state *index = o->src_index;
 393        int len = ce_namelen(ce);
 394        int pos;
 395
 396        for (pos = locate_in_src_index(ce, o); pos < index->cache_nr; pos++) {
 397                struct cache_entry *next = index->cache[pos];
 398                if (len != ce_namelen(next) ||
 399                    memcmp(ce->name, next->name, len))
 400                        break;
 401                mark_ce_used(next, o);
 402        }
 403}
 404
 405static struct cache_entry *next_cache_entry(struct unpack_trees_options *o)
 406{
 407        const struct index_state *index = o->src_index;
 408        int pos = o->cache_bottom;
 409
 410        while (pos < index->cache_nr) {
 411                struct cache_entry *ce = index->cache[pos];
 412                if (!(ce->ce_flags & CE_UNPACKED))
 413                        return ce;
 414                pos++;
 415        }
 416        return NULL;
 417}
 418
 419static void add_same_unmerged(const struct cache_entry *ce,
 420                              struct unpack_trees_options *o)
 421{
 422        struct index_state *index = o->src_index;
 423        int len = ce_namelen(ce);
 424        int pos = index_name_pos(index, ce->name, len);
 425
 426        if (0 <= pos)
 427                die("programming error in a caller of mark_ce_used_same_name");
 428        for (pos = -pos - 1; pos < index->cache_nr; pos++) {
 429                struct cache_entry *next = index->cache[pos];
 430                if (len != ce_namelen(next) ||
 431                    memcmp(ce->name, next->name, len))
 432                        break;
 433                add_entry(o, next, 0, 0);
 434                mark_ce_used(next, o);
 435        }
 436}
 437
 438static int unpack_index_entry(struct cache_entry *ce,
 439                              struct unpack_trees_options *o)
 440{
 441        const struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 442        int ret;
 443
 444        src[0] = ce;
 445
 446        mark_ce_used(ce, o);
 447        if (ce_stage(ce)) {
 448                if (o->skip_unmerged) {
 449                        add_entry(o, ce, 0, 0);
 450                        return 0;
 451                }
 452        }
 453        ret = call_unpack_fn(src, o);
 454        if (ce_stage(ce))
 455                mark_ce_used_same_name(ce, o);
 456        return ret;
 457}
 458
 459static int find_cache_pos(struct traverse_info *, const struct name_entry *);
 460
 461static void restore_cache_bottom(struct traverse_info *info, int bottom)
 462{
 463        struct unpack_trees_options *o = info->data;
 464
 465        if (o->diff_index_cached)
 466                return;
 467        o->cache_bottom = bottom;
 468}
 469
 470static int switch_cache_bottom(struct traverse_info *info)
 471{
 472        struct unpack_trees_options *o = info->data;
 473        int ret, pos;
 474
 475        if (o->diff_index_cached)
 476                return 0;
 477        ret = o->cache_bottom;
 478        pos = find_cache_pos(info->prev, &info->name);
 479
 480        if (pos < -1)
 481                o->cache_bottom = -2 - pos;
 482        else if (pos < 0)
 483                o->cache_bottom = o->src_index->cache_nr;
 484        return ret;
 485}
 486
 487static int traverse_trees_recursive(int n, unsigned long dirmask,
 488                                    unsigned long df_conflicts,
 489                                    struct name_entry *names,
 490                                    struct traverse_info *info)
 491{
 492        int i, ret, bottom;
 493        struct tree_desc t[MAX_UNPACK_TREES];
 494        void *buf[MAX_UNPACK_TREES];
 495        struct traverse_info newinfo;
 496        struct name_entry *p;
 497
 498        p = names;
 499        while (!p->mode)
 500                p++;
 501
 502        newinfo = *info;
 503        newinfo.prev = info;
 504        newinfo.pathspec = info->pathspec;
 505        newinfo.name = *p;
 506        newinfo.pathlen += tree_entry_len(p) + 1;
 507        newinfo.df_conflicts |= df_conflicts;
 508
 509        for (i = 0; i < n; i++, dirmask >>= 1) {
 510                const unsigned char *sha1 = NULL;
 511                if (dirmask & 1)
 512                        sha1 = names[i].oid->hash;
 513                buf[i] = fill_tree_descriptor(t+i, sha1);
 514        }
 515
 516        bottom = switch_cache_bottom(&newinfo);
 517        ret = traverse_trees(n, t, &newinfo);
 518        restore_cache_bottom(&newinfo, bottom);
 519
 520        for (i = 0; i < n; i++)
 521                free(buf[i]);
 522
 523        return ret;
 524}
 525
 526/*
 527 * Compare the traverse-path to the cache entry without actually
 528 * having to generate the textual representation of the traverse
 529 * path.
 530 *
 531 * NOTE! This *only* compares up to the size of the traverse path
 532 * itself - the caller needs to do the final check for the cache
 533 * entry having more data at the end!
 534 */
 535static int do_compare_entry_piecewise(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 536{
 537        int len, pathlen, ce_len;
 538        const char *ce_name;
 539
 540        if (info->prev) {
 541                int cmp = do_compare_entry_piecewise(ce, info->prev,
 542                                                     &info->name);
 543                if (cmp)
 544                        return cmp;
 545        }
 546        pathlen = info->pathlen;
 547        ce_len = ce_namelen(ce);
 548
 549        /* If ce_len < pathlen then we must have previously hit "name == directory" entry */
 550        if (ce_len < pathlen)
 551                return -1;
 552
 553        ce_len -= pathlen;
 554        ce_name = ce->name + pathlen;
 555
 556        len = tree_entry_len(n);
 557        return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 558}
 559
 560static int do_compare_entry(const struct cache_entry *ce,
 561                            const struct traverse_info *info,
 562                            const struct name_entry *n)
 563{
 564        int len, pathlen, ce_len;
 565        const char *ce_name;
 566        int cmp;
 567
 568        /*
 569         * If we have not precomputed the traverse path, it is quicker
 570         * to avoid doing so.  But if we have precomputed it,
 571         * it is quicker to use the precomputed version.
 572         */
 573        if (!info->traverse_path)
 574                return do_compare_entry_piecewise(ce, info, n);
 575
 576        cmp = strncmp(ce->name, info->traverse_path, info->pathlen);
 577        if (cmp)
 578                return cmp;
 579
 580        pathlen = info->pathlen;
 581        ce_len = ce_namelen(ce);
 582
 583        if (ce_len < pathlen)
 584                return -1;
 585
 586        ce_len -= pathlen;
 587        ce_name = ce->name + pathlen;
 588
 589        len = tree_entry_len(n);
 590        return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 591}
 592
 593static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 594{
 595        int cmp = do_compare_entry(ce, info, n);
 596        if (cmp)
 597                return cmp;
 598
 599        /*
 600         * Even if the beginning compared identically, the ce should
 601         * compare as bigger than a directory leading up to it!
 602         */
 603        return ce_namelen(ce) > traverse_path_len(info, n);
 604}
 605
 606static int ce_in_traverse_path(const struct cache_entry *ce,
 607                               const struct traverse_info *info)
 608{
 609        if (!info->prev)
 610                return 1;
 611        if (do_compare_entry(ce, info->prev, &info->name))
 612                return 0;
 613        /*
 614         * If ce (blob) is the same name as the path (which is a tree
 615         * we will be descending into), it won't be inside it.
 616         */
 617        return (info->pathlen < ce_namelen(ce));
 618}
 619
 620static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
 621{
 622        int len = traverse_path_len(info, n);
 623        struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
 624
 625        ce->ce_mode = create_ce_mode(n->mode);
 626        ce->ce_flags = create_ce_flags(stage);
 627        ce->ce_namelen = len;
 628        oidcpy(&ce->oid, n->oid);
 629        make_traverse_path(ce->name, info, n);
 630
 631        return ce;
 632}
 633
 634static int unpack_nondirectories(int n, unsigned long mask,
 635                                 unsigned long dirmask,
 636                                 struct cache_entry **src,
 637                                 const struct name_entry *names,
 638                                 const struct traverse_info *info)
 639{
 640        int i;
 641        struct unpack_trees_options *o = info->data;
 642        unsigned long conflicts = info->df_conflicts | dirmask;
 643
 644        /* Do we have *only* directories? Nothing to do */
 645        if (mask == dirmask && !src[0])
 646                return 0;
 647
 648        /*
 649         * Ok, we've filled in up to any potential index entry in src[0],
 650         * now do the rest.
 651         */
 652        for (i = 0; i < n; i++) {
 653                int stage;
 654                unsigned int bit = 1ul << i;
 655                if (conflicts & bit) {
 656                        src[i + o->merge] = o->df_conflict_entry;
 657                        continue;
 658                }
 659                if (!(mask & bit))
 660                        continue;
 661                if (!o->merge)
 662                        stage = 0;
 663                else if (i + 1 < o->head_idx)
 664                        stage = 1;
 665                else if (i + 1 > o->head_idx)
 666                        stage = 3;
 667                else
 668                        stage = 2;
 669                src[i + o->merge] = create_ce_entry(info, names + i, stage);
 670        }
 671
 672        if (o->merge) {
 673                int rc = call_unpack_fn((const struct cache_entry * const *)src,
 674                                        o);
 675                for (i = 0; i < n; i++) {
 676                        struct cache_entry *ce = src[i + o->merge];
 677                        if (ce != o->df_conflict_entry)
 678                                free(ce);
 679                }
 680                return rc;
 681        }
 682
 683        for (i = 0; i < n; i++)
 684                if (src[i] && src[i] != o->df_conflict_entry)
 685                        if (do_add_entry(o, src[i], 0, 0))
 686                                return -1;
 687
 688        return 0;
 689}
 690
 691static int unpack_failed(struct unpack_trees_options *o, const char *message)
 692{
 693        discard_index(&o->result);
 694        if (!o->gently && !o->exiting_early) {
 695                if (message)
 696                        return error("%s", message);
 697                return -1;
 698        }
 699        return -1;
 700}
 701
 702/*
 703 * The tree traversal is looking at name p.  If we have a matching entry,
 704 * return it.  If name p is a directory in the index, do not return
 705 * anything, as we will want to match it when the traversal descends into
 706 * the directory.
 707 */
 708static int find_cache_pos(struct traverse_info *info,
 709                          const struct name_entry *p)
 710{
 711        int pos;
 712        struct unpack_trees_options *o = info->data;
 713        struct index_state *index = o->src_index;
 714        int pfxlen = info->pathlen;
 715        int p_len = tree_entry_len(p);
 716
 717        for (pos = o->cache_bottom; pos < index->cache_nr; pos++) {
 718                const struct cache_entry *ce = index->cache[pos];
 719                const char *ce_name, *ce_slash;
 720                int cmp, ce_len;
 721
 722                if (ce->ce_flags & CE_UNPACKED) {
 723                        /*
 724                         * cache_bottom entry is already unpacked, so
 725                         * we can never match it; don't check it
 726                         * again.
 727                         */
 728                        if (pos == o->cache_bottom)
 729                                ++o->cache_bottom;
 730                        continue;
 731                }
 732                if (!ce_in_traverse_path(ce, info)) {
 733                        /*
 734                         * Check if we can skip future cache checks
 735                         * (because we're already past all possible
 736                         * entries in the traverse path).
 737                         */
 738                        if (info->traverse_path) {
 739                                if (strncmp(ce->name, info->traverse_path,
 740                                            info->pathlen) > 0)
 741                                        break;
 742                        }
 743                        continue;
 744                }
 745                ce_name = ce->name + pfxlen;
 746                ce_slash = strchr(ce_name, '/');
 747                if (ce_slash)
 748                        ce_len = ce_slash - ce_name;
 749                else
 750                        ce_len = ce_namelen(ce) - pfxlen;
 751                cmp = name_compare(p->path, p_len, ce_name, ce_len);
 752                /*
 753                 * Exact match; if we have a directory we need to
 754                 * delay returning it.
 755                 */
 756                if (!cmp)
 757                        return ce_slash ? -2 - pos : pos;
 758                if (0 < cmp)
 759                        continue; /* keep looking */
 760                /*
 761                 * ce_name sorts after p->path; could it be that we
 762                 * have files under p->path directory in the index?
 763                 * E.g.  ce_name == "t-i", and p->path == "t"; we may
 764                 * have "t/a" in the index.
 765                 */
 766                if (p_len < ce_len && !memcmp(ce_name, p->path, p_len) &&
 767                    ce_name[p_len] < '/')
 768                        continue; /* keep looking */
 769                break;
 770        }
 771        return -1;
 772}
 773
 774static struct cache_entry *find_cache_entry(struct traverse_info *info,
 775                                            const struct name_entry *p)
 776{
 777        int pos = find_cache_pos(info, p);
 778        struct unpack_trees_options *o = info->data;
 779
 780        if (0 <= pos)
 781                return o->src_index->cache[pos];
 782        else
 783                return NULL;
 784}
 785
 786static void debug_path(struct traverse_info *info)
 787{
 788        if (info->prev) {
 789                debug_path(info->prev);
 790                if (*info->prev->name.path)
 791                        putchar('/');
 792        }
 793        printf("%s", info->name.path);
 794}
 795
 796static void debug_name_entry(int i, struct name_entry *n)
 797{
 798        printf("ent#%d %06o %s\n", i,
 799               n->path ? n->mode : 0,
 800               n->path ? n->path : "(missing)");
 801}
 802
 803static void debug_unpack_callback(int n,
 804                                  unsigned long mask,
 805                                  unsigned long dirmask,
 806                                  struct name_entry *names,
 807                                  struct traverse_info *info)
 808{
 809        int i;
 810        printf("* unpack mask %lu, dirmask %lu, cnt %d ",
 811               mask, dirmask, n);
 812        debug_path(info);
 813        putchar('\n');
 814        for (i = 0; i < n; i++)
 815                debug_name_entry(i, names + i);
 816}
 817
 818static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
 819{
 820        struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 821        struct unpack_trees_options *o = info->data;
 822        const struct name_entry *p = names;
 823
 824        /* Find first entry with a real name (we could use "mask" too) */
 825        while (!p->mode)
 826                p++;
 827
 828        if (o->debug_unpack)
 829                debug_unpack_callback(n, mask, dirmask, names, info);
 830
 831        /* Are we supposed to look at the index too? */
 832        if (o->merge) {
 833                while (1) {
 834                        int cmp;
 835                        struct cache_entry *ce;
 836
 837                        if (o->diff_index_cached)
 838                                ce = next_cache_entry(o);
 839                        else
 840                                ce = find_cache_entry(info, p);
 841
 842                        if (!ce)
 843                                break;
 844                        cmp = compare_entry(ce, info, p);
 845                        if (cmp < 0) {
 846                                if (unpack_index_entry(ce, o) < 0)
 847                                        return unpack_failed(o, NULL);
 848                                continue;
 849                        }
 850                        if (!cmp) {
 851                                if (ce_stage(ce)) {
 852                                        /*
 853                                         * If we skip unmerged index
 854                                         * entries, we'll skip this
 855                                         * entry *and* the tree
 856                                         * entries associated with it!
 857                                         */
 858                                        if (o->skip_unmerged) {
 859                                                add_same_unmerged(ce, o);
 860                                                return mask;
 861                                        }
 862                                }
 863                                src[0] = ce;
 864                        }
 865                        break;
 866                }
 867        }
 868
 869        if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
 870                return -1;
 871
 872        if (o->merge && src[0]) {
 873                if (ce_stage(src[0]))
 874                        mark_ce_used_same_name(src[0], o);
 875                else
 876                        mark_ce_used(src[0], o);
 877        }
 878
 879        /* Now handle any directories.. */
 880        if (dirmask) {
 881                /* special case: "diff-index --cached" looking at a tree */
 882                if (o->diff_index_cached &&
 883                    n == 1 && dirmask == 1 && S_ISDIR(names->mode)) {
 884                        int matches;
 885                        matches = cache_tree_matches_traversal(o->src_index->cache_tree,
 886                                                               names, info);
 887                        /*
 888                         * Everything under the name matches; skip the
 889                         * entire hierarchy.  diff_index_cached codepath
 890                         * special cases D/F conflicts in such a way that
 891                         * it does not do any look-ahead, so this is safe.
 892                         */
 893                        if (matches) {
 894                                o->cache_bottom += matches;
 895                                return mask;
 896                        }
 897                }
 898
 899                if (traverse_trees_recursive(n, dirmask, mask & ~dirmask,
 900                                             names, info) < 0)
 901                        return -1;
 902                return mask;
 903        }
 904
 905        return mask;
 906}
 907
 908static int clear_ce_flags_1(struct cache_entry **cache, int nr,
 909                            struct strbuf *prefix,
 910                            int select_mask, int clear_mask,
 911                            struct exclude_list *el, int defval);
 912
 913/* Whole directory matching */
 914static int clear_ce_flags_dir(struct cache_entry **cache, int nr,
 915                              struct strbuf *prefix,
 916                              char *basename,
 917                              int select_mask, int clear_mask,
 918                              struct exclude_list *el, int defval)
 919{
 920        struct cache_entry **cache_end;
 921        int dtype = DT_DIR;
 922        int ret = is_excluded_from_list(prefix->buf, prefix->len,
 923                                        basename, &dtype, el);
 924        int rc;
 925
 926        strbuf_addch(prefix, '/');
 927
 928        /* If undecided, use matching result of parent dir in defval */
 929        if (ret < 0)
 930                ret = defval;
 931
 932        for (cache_end = cache; cache_end != cache + nr; cache_end++) {
 933                struct cache_entry *ce = *cache_end;
 934                if (strncmp(ce->name, prefix->buf, prefix->len))
 935                        break;
 936        }
 937
 938        /*
 939         * TODO: check el, if there are no patterns that may conflict
 940         * with ret (iow, we know in advance the incl/excl
 941         * decision for the entire directory), clear flag here without
 942         * calling clear_ce_flags_1(). That function will call
 943         * the expensive is_excluded_from_list() on every entry.
 944         */
 945        rc = clear_ce_flags_1(cache, cache_end - cache,
 946                              prefix,
 947                              select_mask, clear_mask,
 948                              el, ret);
 949        strbuf_setlen(prefix, prefix->len - 1);
 950        return rc;
 951}
 952
 953/*
 954 * Traverse the index, find every entry that matches according to
 955 * o->el. Do "ce_flags &= ~clear_mask" on those entries. Return the
 956 * number of traversed entries.
 957 *
 958 * If select_mask is non-zero, only entries whose ce_flags has on of
 959 * those bits enabled are traversed.
 960 *
 961 * cache        : pointer to an index entry
 962 * prefix_len   : an offset to its path
 963 *
 964 * The current path ("prefix") including the trailing '/' is
 965 *   cache[0]->name[0..(prefix_len-1)]
 966 * Top level path has prefix_len zero.
 967 */
 968static int clear_ce_flags_1(struct cache_entry **cache, int nr,
 969                            struct strbuf *prefix,
 970                            int select_mask, int clear_mask,
 971                            struct exclude_list *el, int defval)
 972{
 973        struct cache_entry **cache_end = cache + nr;
 974
 975        /*
 976         * Process all entries that have the given prefix and meet
 977         * select_mask condition
 978         */
 979        while(cache != cache_end) {
 980                struct cache_entry *ce = *cache;
 981                const char *name, *slash;
 982                int len, dtype, ret;
 983
 984                if (select_mask && !(ce->ce_flags & select_mask)) {
 985                        cache++;
 986                        continue;
 987                }
 988
 989                if (prefix->len && strncmp(ce->name, prefix->buf, prefix->len))
 990                        break;
 991
 992                name = ce->name + prefix->len;
 993                slash = strchr(name, '/');
 994
 995                /* If it's a directory, try whole directory match first */
 996                if (slash) {
 997                        int processed;
 998
 999                        len = slash - name;
1000                        strbuf_add(prefix, name, len);
1001
1002                        processed = clear_ce_flags_dir(cache, cache_end - cache,
1003                                                       prefix,
1004                                                       prefix->buf + prefix->len - len,
1005                                                       select_mask, clear_mask,
1006                                                       el, defval);
1007
1008                        /* clear_c_f_dir eats a whole dir already? */
1009                        if (processed) {
1010                                cache += processed;
1011                                strbuf_setlen(prefix, prefix->len - len);
1012                                continue;
1013                        }
1014
1015                        strbuf_addch(prefix, '/');
1016                        cache += clear_ce_flags_1(cache, cache_end - cache,
1017                                                  prefix,
1018                                                  select_mask, clear_mask, el, defval);
1019                        strbuf_setlen(prefix, prefix->len - len - 1);
1020                        continue;
1021                }
1022
1023                /* Non-directory */
1024                dtype = ce_to_dtype(ce);
1025                ret = is_excluded_from_list(ce->name, ce_namelen(ce),
1026                                            name, &dtype, el);
1027                if (ret < 0)
1028                        ret = defval;
1029                if (ret > 0)
1030                        ce->ce_flags &= ~clear_mask;
1031                cache++;
1032        }
1033        return nr - (cache_end - cache);
1034}
1035
1036static int clear_ce_flags(struct cache_entry **cache, int nr,
1037                            int select_mask, int clear_mask,
1038                            struct exclude_list *el)
1039{
1040        static struct strbuf prefix = STRBUF_INIT;
1041
1042        strbuf_reset(&prefix);
1043
1044        return clear_ce_flags_1(cache, nr,
1045                                &prefix,
1046                                select_mask, clear_mask,
1047                                el, 0);
1048}
1049
1050/*
1051 * Set/Clear CE_NEW_SKIP_WORKTREE according to $GIT_DIR/info/sparse-checkout
1052 */
1053static void mark_new_skip_worktree(struct exclude_list *el,
1054                                   struct index_state *the_index,
1055                                   int select_flag, int skip_wt_flag)
1056{
1057        int i;
1058
1059        /*
1060         * 1. Pretend the narrowest worktree: only unmerged entries
1061         * are checked out
1062         */
1063        for (i = 0; i < the_index->cache_nr; i++) {
1064                struct cache_entry *ce = the_index->cache[i];
1065
1066                if (select_flag && !(ce->ce_flags & select_flag))
1067                        continue;
1068
1069                if (!ce_stage(ce))
1070                        ce->ce_flags |= skip_wt_flag;
1071                else
1072                        ce->ce_flags &= ~skip_wt_flag;
1073        }
1074
1075        /*
1076         * 2. Widen worktree according to sparse-checkout file.
1077         * Matched entries will have skip_wt_flag cleared (i.e. "in")
1078         */
1079        clear_ce_flags(the_index->cache, the_index->cache_nr,
1080                       select_flag, skip_wt_flag, el);
1081}
1082
1083static int verify_absent(const struct cache_entry *,
1084                         enum unpack_trees_error_types,
1085                         struct unpack_trees_options *);
1086/*
1087 * N-way merge "len" trees.  Returns 0 on success, -1 on failure to manipulate the
1088 * resulting index, -2 on failure to reflect the changes to the work tree.
1089 *
1090 * CE_ADDED, CE_UNPACKED and CE_NEW_SKIP_WORKTREE are used internally
1091 */
1092int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
1093{
1094        int i, ret;
1095        static struct cache_entry *dfc;
1096        struct exclude_list el;
1097        struct checkout state = CHECKOUT_INIT;
1098
1099        if (len > MAX_UNPACK_TREES)
1100                die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
1101        state.force = 1;
1102        state.quiet = 1;
1103        state.refresh_cache = 1;
1104        state.istate = &o->result;
1105
1106        memset(&el, 0, sizeof(el));
1107        if (!core_apply_sparse_checkout || !o->update)
1108                o->skip_sparse_checkout = 1;
1109        if (!o->skip_sparse_checkout) {
1110                char *sparse = git_pathdup("info/sparse-checkout");
1111                if (add_excludes_from_file_to_list(sparse, "", 0, &el, 0) < 0)
1112                        o->skip_sparse_checkout = 1;
1113                else
1114                        o->el = &el;
1115                free(sparse);
1116        }
1117
1118        memset(&o->result, 0, sizeof(o->result));
1119        o->result.initialized = 1;
1120        o->result.timestamp.sec = o->src_index->timestamp.sec;
1121        o->result.timestamp.nsec = o->src_index->timestamp.nsec;
1122        o->result.version = o->src_index->version;
1123        o->result.split_index = o->src_index->split_index;
1124        if (o->result.split_index)
1125                o->result.split_index->refcount++;
1126        hashcpy(o->result.sha1, o->src_index->sha1);
1127        o->merge_size = len;
1128        mark_all_ce_unused(o->src_index);
1129
1130        /*
1131         * Sparse checkout loop #1: set NEW_SKIP_WORKTREE on existing entries
1132         */
1133        if (!o->skip_sparse_checkout)
1134                mark_new_skip_worktree(o->el, o->src_index, 0, CE_NEW_SKIP_WORKTREE);
1135
1136        if (!dfc)
1137                dfc = xcalloc(1, cache_entry_size(0));
1138        o->df_conflict_entry = dfc;
1139
1140        if (len) {
1141                const char *prefix = o->prefix ? o->prefix : "";
1142                struct traverse_info info;
1143
1144                setup_traverse_info(&info, prefix);
1145                info.fn = unpack_callback;
1146                info.data = o;
1147                info.show_all_errors = o->show_all_errors;
1148                info.pathspec = o->pathspec;
1149
1150                if (o->prefix) {
1151                        /*
1152                         * Unpack existing index entries that sort before the
1153                         * prefix the tree is spliced into.  Note that o->merge
1154                         * is always true in this case.
1155                         */
1156                        while (1) {
1157                                struct cache_entry *ce = next_cache_entry(o);
1158                                if (!ce)
1159                                        break;
1160                                if (ce_in_traverse_path(ce, &info))
1161                                        break;
1162                                if (unpack_index_entry(ce, o) < 0)
1163                                        goto return_failed;
1164                        }
1165                }
1166
1167                if (traverse_trees(len, t, &info) < 0)
1168                        goto return_failed;
1169        }
1170
1171        /* Any left-over entries in the index? */
1172        if (o->merge) {
1173                while (1) {
1174                        struct cache_entry *ce = next_cache_entry(o);
1175                        if (!ce)
1176                                break;
1177                        if (unpack_index_entry(ce, o) < 0)
1178                                goto return_failed;
1179                }
1180        }
1181        mark_all_ce_unused(o->src_index);
1182
1183        if (o->trivial_merges_only && o->nontrivial_merge) {
1184                ret = unpack_failed(o, "Merge requires file-level merging");
1185                goto done;
1186        }
1187
1188        if (!o->skip_sparse_checkout) {
1189                int empty_worktree = 1;
1190
1191                /*
1192                 * Sparse checkout loop #2: set NEW_SKIP_WORKTREE on entries not in loop #1
1193                 * If the will have NEW_SKIP_WORKTREE, also set CE_SKIP_WORKTREE
1194                 * so apply_sparse_checkout() won't attempt to remove it from worktree
1195                 */
1196                mark_new_skip_worktree(o->el, &o->result, CE_ADDED, CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1197
1198                ret = 0;
1199                for (i = 0; i < o->result.cache_nr; i++) {
1200                        struct cache_entry *ce = o->result.cache[i];
1201
1202                        /*
1203                         * Entries marked with CE_ADDED in merged_entry() do not have
1204                         * verify_absent() check (the check is effectively disabled
1205                         * because CE_NEW_SKIP_WORKTREE is set unconditionally).
1206                         *
1207                         * Do the real check now because we have had
1208                         * correct CE_NEW_SKIP_WORKTREE
1209                         */
1210                        if (ce->ce_flags & CE_ADDED &&
1211                            verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1212                                if (!o->show_all_errors)
1213                                        goto return_failed;
1214                                ret = -1;
1215                        }
1216
1217                        if (apply_sparse_checkout(&o->result, ce, o)) {
1218                                if (!o->show_all_errors)
1219                                        goto return_failed;
1220                                ret = -1;
1221                        }
1222                        if (!ce_skip_worktree(ce))
1223                                empty_worktree = 0;
1224
1225                }
1226                if (ret < 0)
1227                        goto return_failed;
1228                /*
1229                 * Sparse checkout is meant to narrow down checkout area
1230                 * but it does not make sense to narrow down to empty working
1231                 * tree. This is usually a mistake in sparse checkout rules.
1232                 * Do not allow users to do that.
1233                 */
1234                if (o->result.cache_nr && empty_worktree) {
1235                        ret = unpack_failed(o, "Sparse checkout leaves no entry on working directory");
1236                        goto done;
1237                }
1238        }
1239
1240        o->src_index = NULL;
1241        ret = check_updates(o, &state) ? (-2) : 0;
1242        if (o->dst_index) {
1243                if (!ret) {
1244                        if (!o->result.cache_tree)
1245                                o->result.cache_tree = cache_tree();
1246                        if (!cache_tree_fully_valid(o->result.cache_tree))
1247                                cache_tree_update(&o->result,
1248                                                  WRITE_TREE_SILENT |
1249                                                  WRITE_TREE_REPAIR);
1250                }
1251                discard_index(o->dst_index);
1252                *o->dst_index = o->result;
1253        } else {
1254                discard_index(&o->result);
1255        }
1256
1257done:
1258        clear_exclude_list(&el);
1259        return ret;
1260
1261return_failed:
1262        if (o->show_all_errors)
1263                display_error_msgs(o);
1264        mark_all_ce_unused(o->src_index);
1265        ret = unpack_failed(o, NULL);
1266        if (o->exiting_early)
1267                ret = 0;
1268        goto done;
1269}
1270
1271/* Here come the merge functions */
1272
1273static int reject_merge(const struct cache_entry *ce,
1274                        struct unpack_trees_options *o)
1275{
1276        return o->gently ? -1 :
1277                add_rejected_path(o, ERROR_WOULD_OVERWRITE, ce->name);
1278}
1279
1280static int same(const struct cache_entry *a, const struct cache_entry *b)
1281{
1282        if (!!a != !!b)
1283                return 0;
1284        if (!a && !b)
1285                return 1;
1286        if ((a->ce_flags | b->ce_flags) & CE_CONFLICTED)
1287                return 0;
1288        return a->ce_mode == b->ce_mode &&
1289               !oidcmp(&a->oid, &b->oid);
1290}
1291
1292
1293/*
1294 * When a CE gets turned into an unmerged entry, we
1295 * want it to be up-to-date
1296 */
1297static int verify_uptodate_1(const struct cache_entry *ce,
1298                             struct unpack_trees_options *o,
1299                             enum unpack_trees_error_types error_type)
1300{
1301        struct stat st;
1302
1303        if (o->index_only)
1304                return 0;
1305
1306        /*
1307         * CE_VALID and CE_SKIP_WORKTREE cheat, we better check again
1308         * if this entry is truly up-to-date because this file may be
1309         * overwritten.
1310         */
1311        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
1312                ; /* keep checking */
1313        else if (o->reset || ce_uptodate(ce))
1314                return 0;
1315
1316        if (!lstat(ce->name, &st)) {
1317                int flags = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE;
1318                unsigned changed = ie_match_stat(o->src_index, ce, &st, flags);
1319                if (!changed)
1320                        return 0;
1321                /*
1322                 * NEEDSWORK: the current default policy is to allow
1323                 * submodule to be out of sync wrt the superproject
1324                 * index.  This needs to be tightened later for
1325                 * submodules that are marked to be automatically
1326                 * checked out.
1327                 */
1328                if (S_ISGITLINK(ce->ce_mode))
1329                        return 0;
1330                errno = 0;
1331        }
1332        if (errno == ENOENT)
1333                return 0;
1334        return o->gently ? -1 :
1335                add_rejected_path(o, error_type, ce->name);
1336}
1337
1338static int verify_uptodate(const struct cache_entry *ce,
1339                           struct unpack_trees_options *o)
1340{
1341        if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1342                return 0;
1343        return verify_uptodate_1(ce, o, ERROR_NOT_UPTODATE_FILE);
1344}
1345
1346static int verify_uptodate_sparse(const struct cache_entry *ce,
1347                                  struct unpack_trees_options *o)
1348{
1349        return verify_uptodate_1(ce, o, ERROR_SPARSE_NOT_UPTODATE_FILE);
1350}
1351
1352static void invalidate_ce_path(const struct cache_entry *ce,
1353                               struct unpack_trees_options *o)
1354{
1355        if (!ce)
1356                return;
1357        cache_tree_invalidate_path(o->src_index, ce->name);
1358        untracked_cache_invalidate_path(o->src_index, ce->name);
1359}
1360
1361/*
1362 * Check that checking out ce->sha1 in subdir ce->name is not
1363 * going to overwrite any working files.
1364 *
1365 * Currently, git does not checkout subprojects during a superproject
1366 * checkout, so it is not going to overwrite anything.
1367 */
1368static int verify_clean_submodule(const struct cache_entry *ce,
1369                                  enum unpack_trees_error_types error_type,
1370                                  struct unpack_trees_options *o)
1371{
1372        return 0;
1373}
1374
1375static int verify_clean_subdirectory(const struct cache_entry *ce,
1376                                     enum unpack_trees_error_types error_type,
1377                                     struct unpack_trees_options *o)
1378{
1379        /*
1380         * we are about to extract "ce->name"; we would not want to lose
1381         * anything in the existing directory there.
1382         */
1383        int namelen;
1384        int i;
1385        struct dir_struct d;
1386        char *pathbuf;
1387        int cnt = 0;
1388        unsigned char sha1[20];
1389
1390        if (S_ISGITLINK(ce->ce_mode) &&
1391            resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
1392                /* If we are not going to update the submodule, then
1393                 * we don't care.
1394                 */
1395                if (!hashcmp(sha1, ce->oid.hash))
1396                        return 0;
1397                return verify_clean_submodule(ce, error_type, o);
1398        }
1399
1400        /*
1401         * First let's make sure we do not have a local modification
1402         * in that directory.
1403         */
1404        namelen = ce_namelen(ce);
1405        for (i = locate_in_src_index(ce, o);
1406             i < o->src_index->cache_nr;
1407             i++) {
1408                struct cache_entry *ce2 = o->src_index->cache[i];
1409                int len = ce_namelen(ce2);
1410                if (len < namelen ||
1411                    strncmp(ce->name, ce2->name, namelen) ||
1412                    ce2->name[namelen] != '/')
1413                        break;
1414                /*
1415                 * ce2->name is an entry in the subdirectory to be
1416                 * removed.
1417                 */
1418                if (!ce_stage(ce2)) {
1419                        if (verify_uptodate(ce2, o))
1420                                return -1;
1421                        add_entry(o, ce2, CE_REMOVE, 0);
1422                        mark_ce_used(ce2, o);
1423                }
1424                cnt++;
1425        }
1426
1427        /*
1428         * Then we need to make sure that we do not lose a locally
1429         * present file that is not ignored.
1430         */
1431        pathbuf = xstrfmt("%.*s/", namelen, ce->name);
1432
1433        memset(&d, 0, sizeof(d));
1434        if (o->dir)
1435                d.exclude_per_dir = o->dir->exclude_per_dir;
1436        i = read_directory(&d, pathbuf, namelen+1, NULL);
1437        if (i)
1438                return o->gently ? -1 :
1439                        add_rejected_path(o, ERROR_NOT_UPTODATE_DIR, ce->name);
1440        free(pathbuf);
1441        return cnt;
1442}
1443
1444/*
1445 * This gets called when there was no index entry for the tree entry 'dst',
1446 * but we found a file in the working tree that 'lstat()' said was fine,
1447 * and we're on a case-insensitive filesystem.
1448 *
1449 * See if we can find a case-insensitive match in the index that also
1450 * matches the stat information, and assume it's that other file!
1451 */
1452static int icase_exists(struct unpack_trees_options *o, const char *name, int len, struct stat *st)
1453{
1454        const struct cache_entry *src;
1455
1456        src = index_file_exists(o->src_index, name, len, 1);
1457        return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
1458}
1459
1460static int check_ok_to_remove(const char *name, int len, int dtype,
1461                              const struct cache_entry *ce, struct stat *st,
1462                              enum unpack_trees_error_types error_type,
1463                              struct unpack_trees_options *o)
1464{
1465        const struct cache_entry *result;
1466
1467        /*
1468         * It may be that the 'lstat()' succeeded even though
1469         * target 'ce' was absent, because there is an old
1470         * entry that is different only in case..
1471         *
1472         * Ignore that lstat() if it matches.
1473         */
1474        if (ignore_case && icase_exists(o, name, len, st))
1475                return 0;
1476
1477        if (o->dir &&
1478            is_excluded(o->dir, name, &dtype))
1479                /*
1480                 * ce->name is explicitly excluded, so it is Ok to
1481                 * overwrite it.
1482                 */
1483                return 0;
1484        if (S_ISDIR(st->st_mode)) {
1485                /*
1486                 * We are checking out path "foo" and
1487                 * found "foo/." in the working tree.
1488                 * This is tricky -- if we have modified
1489                 * files that are in "foo/" we would lose
1490                 * them.
1491                 */
1492                if (verify_clean_subdirectory(ce, error_type, o) < 0)
1493                        return -1;
1494                return 0;
1495        }
1496
1497        /*
1498         * The previous round may already have decided to
1499         * delete this path, which is in a subdirectory that
1500         * is being replaced with a blob.
1501         */
1502        result = index_file_exists(&o->result, name, len, 0);
1503        if (result) {
1504                if (result->ce_flags & CE_REMOVE)
1505                        return 0;
1506        }
1507
1508        return o->gently ? -1 :
1509                add_rejected_path(o, error_type, name);
1510}
1511
1512/*
1513 * We do not want to remove or overwrite a working tree file that
1514 * is not tracked, unless it is ignored.
1515 */
1516static int verify_absent_1(const struct cache_entry *ce,
1517                           enum unpack_trees_error_types error_type,
1518                           struct unpack_trees_options *o)
1519{
1520        int len;
1521        struct stat st;
1522
1523        if (o->index_only || o->reset || !o->update)
1524                return 0;
1525
1526        len = check_leading_path(ce->name, ce_namelen(ce));
1527        if (!len)
1528                return 0;
1529        else if (len > 0) {
1530                char *path;
1531                int ret;
1532
1533                path = xmemdupz(ce->name, len);
1534                if (lstat(path, &st))
1535                        ret = error_errno("cannot stat '%s'", path);
1536                else
1537                        ret = check_ok_to_remove(path, len, DT_UNKNOWN, NULL,
1538                                                 &st, error_type, o);
1539                free(path);
1540                return ret;
1541        } else if (lstat(ce->name, &st)) {
1542                if (errno != ENOENT)
1543                        return error_errno("cannot stat '%s'", ce->name);
1544                return 0;
1545        } else {
1546                return check_ok_to_remove(ce->name, ce_namelen(ce),
1547                                          ce_to_dtype(ce), ce, &st,
1548                                          error_type, o);
1549        }
1550}
1551
1552static int verify_absent(const struct cache_entry *ce,
1553                         enum unpack_trees_error_types error_type,
1554                         struct unpack_trees_options *o)
1555{
1556        if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1557                return 0;
1558        return verify_absent_1(ce, error_type, o);
1559}
1560
1561static int verify_absent_sparse(const struct cache_entry *ce,
1562                                enum unpack_trees_error_types error_type,
1563                                struct unpack_trees_options *o)
1564{
1565        enum unpack_trees_error_types orphaned_error = error_type;
1566        if (orphaned_error == ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN)
1567                orphaned_error = ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN;
1568
1569        return verify_absent_1(ce, orphaned_error, o);
1570}
1571
1572static int merged_entry(const struct cache_entry *ce,
1573                        const struct cache_entry *old,
1574                        struct unpack_trees_options *o)
1575{
1576        int update = CE_UPDATE;
1577        struct cache_entry *merge = dup_entry(ce);
1578
1579        if (!old) {
1580                /*
1581                 * New index entries. In sparse checkout, the following
1582                 * verify_absent() will be delayed until after
1583                 * traverse_trees() finishes in unpack_trees(), then:
1584                 *
1585                 *  - CE_NEW_SKIP_WORKTREE will be computed correctly
1586                 *  - verify_absent() be called again, this time with
1587                 *    correct CE_NEW_SKIP_WORKTREE
1588                 *
1589                 * verify_absent() call here does nothing in sparse
1590                 * checkout (i.e. o->skip_sparse_checkout == 0)
1591                 */
1592                update |= CE_ADDED;
1593                merge->ce_flags |= CE_NEW_SKIP_WORKTREE;
1594
1595                if (verify_absent(merge,
1596                                  ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1597                        free(merge);
1598                        return -1;
1599                }
1600                invalidate_ce_path(merge, o);
1601        } else if (!(old->ce_flags & CE_CONFLICTED)) {
1602                /*
1603                 * See if we can re-use the old CE directly?
1604                 * That way we get the uptodate stat info.
1605                 *
1606                 * This also removes the UPDATE flag on a match; otherwise
1607                 * we will end up overwriting local changes in the work tree.
1608                 */
1609                if (same(old, merge)) {
1610                        copy_cache_entry(merge, old);
1611                        update = 0;
1612                } else {
1613                        if (verify_uptodate(old, o)) {
1614                                free(merge);
1615                                return -1;
1616                        }
1617                        /* Migrate old flags over */
1618                        update |= old->ce_flags & (CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1619                        invalidate_ce_path(old, o);
1620                }
1621        } else {
1622                /*
1623                 * Previously unmerged entry left as an existence
1624                 * marker by read_index_unmerged();
1625                 */
1626                invalidate_ce_path(old, o);
1627        }
1628
1629        do_add_entry(o, merge, update, CE_STAGEMASK);
1630        return 1;
1631}
1632
1633static int deleted_entry(const struct cache_entry *ce,
1634                         const struct cache_entry *old,
1635                         struct unpack_trees_options *o)
1636{
1637        /* Did it exist in the index? */
1638        if (!old) {
1639                if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1640                        return -1;
1641                return 0;
1642        }
1643        if (!(old->ce_flags & CE_CONFLICTED) && verify_uptodate(old, o))
1644                return -1;
1645        add_entry(o, ce, CE_REMOVE, 0);
1646        invalidate_ce_path(ce, o);
1647        return 1;
1648}
1649
1650static int keep_entry(const struct cache_entry *ce,
1651                      struct unpack_trees_options *o)
1652{
1653        add_entry(o, ce, 0, 0);
1654        return 1;
1655}
1656
1657#if DBRT_DEBUG
1658static void show_stage_entry(FILE *o,
1659                             const char *label, const struct cache_entry *ce)
1660{
1661        if (!ce)
1662                fprintf(o, "%s (missing)\n", label);
1663        else
1664                fprintf(o, "%s%06o %s %d\t%s\n",
1665                        label,
1666                        ce->ce_mode,
1667                        oid_to_hex(&ce->oid),
1668                        ce_stage(ce),
1669                        ce->name);
1670}
1671#endif
1672
1673int threeway_merge(const struct cache_entry * const *stages,
1674                   struct unpack_trees_options *o)
1675{
1676        const struct cache_entry *index;
1677        const struct cache_entry *head;
1678        const struct cache_entry *remote = stages[o->head_idx + 1];
1679        int count;
1680        int head_match = 0;
1681        int remote_match = 0;
1682
1683        int df_conflict_head = 0;
1684        int df_conflict_remote = 0;
1685
1686        int any_anc_missing = 0;
1687        int no_anc_exists = 1;
1688        int i;
1689
1690        for (i = 1; i < o->head_idx; i++) {
1691                if (!stages[i] || stages[i] == o->df_conflict_entry)
1692                        any_anc_missing = 1;
1693                else
1694                        no_anc_exists = 0;
1695        }
1696
1697        index = stages[0];
1698        head = stages[o->head_idx];
1699
1700        if (head == o->df_conflict_entry) {
1701                df_conflict_head = 1;
1702                head = NULL;
1703        }
1704
1705        if (remote == o->df_conflict_entry) {
1706                df_conflict_remote = 1;
1707                remote = NULL;
1708        }
1709
1710        /*
1711         * First, if there's a #16 situation, note that to prevent #13
1712         * and #14.
1713         */
1714        if (!same(remote, head)) {
1715                for (i = 1; i < o->head_idx; i++) {
1716                        if (same(stages[i], head)) {
1717                                head_match = i;
1718                        }
1719                        if (same(stages[i], remote)) {
1720                                remote_match = i;
1721                        }
1722                }
1723        }
1724
1725        /*
1726         * We start with cases where the index is allowed to match
1727         * something other than the head: #14(ALT) and #2ALT, where it
1728         * is permitted to match the result instead.
1729         */
1730        /* #14, #14ALT, #2ALT */
1731        if (remote && !df_conflict_head && head_match && !remote_match) {
1732                if (index && !same(index, remote) && !same(index, head))
1733                        return reject_merge(index, o);
1734                return merged_entry(remote, index, o);
1735        }
1736        /*
1737         * If we have an entry in the index cache, then we want to
1738         * make sure that it matches head.
1739         */
1740        if (index && !same(index, head))
1741                return reject_merge(index, o);
1742
1743        if (head) {
1744                /* #5ALT, #15 */
1745                if (same(head, remote))
1746                        return merged_entry(head, index, o);
1747                /* #13, #3ALT */
1748                if (!df_conflict_remote && remote_match && !head_match)
1749                        return merged_entry(head, index, o);
1750        }
1751
1752        /* #1 */
1753        if (!head && !remote && any_anc_missing)
1754                return 0;
1755
1756        /*
1757         * Under the "aggressive" rule, we resolve mostly trivial
1758         * cases that we historically had git-merge-one-file resolve.
1759         */
1760        if (o->aggressive) {
1761                int head_deleted = !head;
1762                int remote_deleted = !remote;
1763                const struct cache_entry *ce = NULL;
1764
1765                if (index)
1766                        ce = index;
1767                else if (head)
1768                        ce = head;
1769                else if (remote)
1770                        ce = remote;
1771                else {
1772                        for (i = 1; i < o->head_idx; i++) {
1773                                if (stages[i] && stages[i] != o->df_conflict_entry) {
1774                                        ce = stages[i];
1775                                        break;
1776                                }
1777                        }
1778                }
1779
1780                /*
1781                 * Deleted in both.
1782                 * Deleted in one and unchanged in the other.
1783                 */
1784                if ((head_deleted && remote_deleted) ||
1785                    (head_deleted && remote && remote_match) ||
1786                    (remote_deleted && head && head_match)) {
1787                        if (index)
1788                                return deleted_entry(index, index, o);
1789                        if (ce && !head_deleted) {
1790                                if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1791                                        return -1;
1792                        }
1793                        return 0;
1794                }
1795                /*
1796                 * Added in both, identically.
1797                 */
1798                if (no_anc_exists && head && remote && same(head, remote))
1799                        return merged_entry(head, index, o);
1800
1801        }
1802
1803        /* Below are "no merge" cases, which require that the index be
1804         * up-to-date to avoid the files getting overwritten with
1805         * conflict resolution files.
1806         */
1807        if (index) {
1808                if (verify_uptodate(index, o))
1809                        return -1;
1810        }
1811
1812        o->nontrivial_merge = 1;
1813
1814        /* #2, #3, #4, #6, #7, #9, #10, #11. */
1815        count = 0;
1816        if (!head_match || !remote_match) {
1817                for (i = 1; i < o->head_idx; i++) {
1818                        if (stages[i] && stages[i] != o->df_conflict_entry) {
1819                                keep_entry(stages[i], o);
1820                                count++;
1821                                break;
1822                        }
1823                }
1824        }
1825#if DBRT_DEBUG
1826        else {
1827                fprintf(stderr, "read-tree: warning #16 detected\n");
1828                show_stage_entry(stderr, "head   ", stages[head_match]);
1829                show_stage_entry(stderr, "remote ", stages[remote_match]);
1830        }
1831#endif
1832        if (head) { count += keep_entry(head, o); }
1833        if (remote) { count += keep_entry(remote, o); }
1834        return count;
1835}
1836
1837/*
1838 * Two-way merge.
1839 *
1840 * The rule is to "carry forward" what is in the index without losing
1841 * information across a "fast-forward", favoring a successful merge
1842 * over a merge failure when it makes sense.  For details of the
1843 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
1844 *
1845 */
1846int twoway_merge(const struct cache_entry * const *src,
1847                 struct unpack_trees_options *o)
1848{
1849        const struct cache_entry *current = src[0];
1850        const struct cache_entry *oldtree = src[1];
1851        const struct cache_entry *newtree = src[2];
1852
1853        if (o->merge_size != 2)
1854                return error("Cannot do a twoway merge of %d trees",
1855                             o->merge_size);
1856
1857        if (oldtree == o->df_conflict_entry)
1858                oldtree = NULL;
1859        if (newtree == o->df_conflict_entry)
1860                newtree = NULL;
1861
1862        if (current) {
1863                if (current->ce_flags & CE_CONFLICTED) {
1864                        if (same(oldtree, newtree) || o->reset) {
1865                                if (!newtree)
1866                                        return deleted_entry(current, current, o);
1867                                else
1868                                        return merged_entry(newtree, current, o);
1869                        }
1870                        return reject_merge(current, o);
1871                } else if ((!oldtree && !newtree) || /* 4 and 5 */
1872                         (!oldtree && newtree &&
1873                          same(current, newtree)) || /* 6 and 7 */
1874                         (oldtree && newtree &&
1875                          same(oldtree, newtree)) || /* 14 and 15 */
1876                         (oldtree && newtree &&
1877                          !same(oldtree, newtree) && /* 18 and 19 */
1878                          same(current, newtree))) {
1879                        return keep_entry(current, o);
1880                } else if (oldtree && !newtree && same(current, oldtree)) {
1881                        /* 10 or 11 */
1882                        return deleted_entry(oldtree, current, o);
1883                } else if (oldtree && newtree &&
1884                         same(current, oldtree) && !same(current, newtree)) {
1885                        /* 20 or 21 */
1886                        return merged_entry(newtree, current, o);
1887                } else
1888                        return reject_merge(current, o);
1889        }
1890        else if (newtree) {
1891                if (oldtree && !o->initial_checkout) {
1892                        /*
1893                         * deletion of the path was staged;
1894                         */
1895                        if (same(oldtree, newtree))
1896                                return 1;
1897                        return reject_merge(oldtree, o);
1898                }
1899                return merged_entry(newtree, current, o);
1900        }
1901        return deleted_entry(oldtree, current, o);
1902}
1903
1904/*
1905 * Bind merge.
1906 *
1907 * Keep the index entries at stage0, collapse stage1 but make sure
1908 * stage0 does not have anything there.
1909 */
1910int bind_merge(const struct cache_entry * const *src,
1911               struct unpack_trees_options *o)
1912{
1913        const struct cache_entry *old = src[0];
1914        const struct cache_entry *a = src[1];
1915
1916        if (o->merge_size != 1)
1917                return error("Cannot do a bind merge of %d trees",
1918                             o->merge_size);
1919        if (a && old)
1920                return o->gently ? -1 :
1921                        error(ERRORMSG(o, ERROR_BIND_OVERLAP), a->name, old->name);
1922        if (!a)
1923                return keep_entry(old, o);
1924        else
1925                return merged_entry(a, NULL, o);
1926}
1927
1928/*
1929 * One-way merge.
1930 *
1931 * The rule is:
1932 * - take the stat information from stage0, take the data from stage1
1933 */
1934int oneway_merge(const struct cache_entry * const *src,
1935                 struct unpack_trees_options *o)
1936{
1937        const struct cache_entry *old = src[0];
1938        const struct cache_entry *a = src[1];
1939
1940        if (o->merge_size != 1)
1941                return error("Cannot do a oneway merge of %d trees",
1942                             o->merge_size);
1943
1944        if (!a || a == o->df_conflict_entry)
1945                return deleted_entry(old, old, o);
1946
1947        if (old && same(old, a)) {
1948                int update = 0;
1949                if (o->reset && o->update && !ce_uptodate(old) && !ce_skip_worktree(old)) {
1950                        struct stat st;
1951                        if (lstat(old->name, &st) ||
1952                            ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
1953                                update |= CE_UPDATE;
1954                }
1955                add_entry(o, old, update, 0);
1956                return 0;
1957        }
1958        return merged_entry(a, old, o);
1959}