unpack-trees.con commit Merge branch 'jk/sanity' (4b16573)
   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        const char *cmd2 = strcmp(cmd, "checkout") ? cmd : "switch branches";
  62
  63        if (advice_commit_before_merge)
  64                msg = "Your local changes to the following files would be overwritten by %s:\n%%s"
  65                        "Please, commit your changes or stash them before you can %s.";
  66        else
  67                msg = "Your local changes to the following files would be overwritten by %s:\n%%s";
  68        msgs[ERROR_WOULD_OVERWRITE] = msgs[ERROR_NOT_UPTODATE_FILE] =
  69                xstrfmt(msg, cmd, cmd2);
  70
  71        msgs[ERROR_NOT_UPTODATE_DIR] =
  72                "Updating the following directories would lose untracked files in it:\n%s";
  73
  74        if (advice_commit_before_merge)
  75                msg = "The following untracked working tree files would be %s by %s:\n%%s"
  76                        "Please move or remove them before you can %s.";
  77        else
  78                msg = "The following untracked working tree files would be %s by %s:\n%%s";
  79
  80        msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = xstrfmt(msg, "removed", cmd, cmd2);
  81        msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = xstrfmt(msg, "overwritten", cmd, cmd2);
  82
  83        /*
  84         * Special case: ERROR_BIND_OVERLAP refers to a pair of paths, we
  85         * cannot easily display it as a list.
  86         */
  87        msgs[ERROR_BIND_OVERLAP] = "Entry '%s' overlaps with '%s'.  Cannot bind.";
  88
  89        msgs[ERROR_SPARSE_NOT_UPTODATE_FILE] =
  90                "Cannot update sparse checkout: the following entries are not up-to-date:\n%s";
  91        msgs[ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN] =
  92                "The following Working tree files would be overwritten by sparse checkout update:\n%s";
  93        msgs[ERROR_WOULD_LOSE_ORPHANED_REMOVED] =
  94                "The following Working tree files would be removed by sparse checkout update:\n%s";
  95
  96        opts->show_all_errors = 1;
  97        /* rejected paths may not have a static buffer */
  98        for (i = 0; i < ARRAY_SIZE(opts->unpack_rejects); i++)
  99                opts->unpack_rejects[i].strdup_strings = 1;
 100}
 101
 102static int do_add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
 103                         unsigned int set, unsigned int clear)
 104{
 105        clear |= CE_HASHED;
 106
 107        if (set & CE_REMOVE)
 108                set |= CE_WT_REMOVE;
 109
 110        ce->ce_flags = (ce->ce_flags & ~clear) | set;
 111        return add_index_entry(&o->result, ce,
 112                               ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 113}
 114
 115static struct cache_entry *dup_entry(const struct cache_entry *ce)
 116{
 117        unsigned int size = ce_size(ce);
 118        struct cache_entry *new = xmalloc(size);
 119
 120        memcpy(new, ce, size);
 121        return new;
 122}
 123
 124static void add_entry(struct unpack_trees_options *o,
 125                      const struct cache_entry *ce,
 126                      unsigned int set, unsigned int clear)
 127{
 128        do_add_entry(o, dup_entry(ce), set, clear);
 129}
 130
 131/*
 132 * add error messages on path <path>
 133 * corresponding to the type <e> with the message <msg>
 134 * indicating if it should be display in porcelain or not
 135 */
 136static int add_rejected_path(struct unpack_trees_options *o,
 137                             enum unpack_trees_error_types e,
 138                             const char *path)
 139{
 140        if (!o->show_all_errors)
 141                return error(ERRORMSG(o, e), path);
 142
 143        /*
 144         * Otherwise, insert in a list for future display by
 145         * display_error_msgs()
 146         */
 147        string_list_append(&o->unpack_rejects[e], path);
 148        return -1;
 149}
 150
 151/*
 152 * display all the error messages stored in a nice way
 153 */
 154static void display_error_msgs(struct unpack_trees_options *o)
 155{
 156        int e, i;
 157        int something_displayed = 0;
 158        for (e = 0; e < NB_UNPACK_TREES_ERROR_TYPES; e++) {
 159                struct string_list *rejects = &o->unpack_rejects[e];
 160                if (rejects->nr > 0) {
 161                        struct strbuf path = STRBUF_INIT;
 162                        something_displayed = 1;
 163                        for (i = 0; i < rejects->nr; i++)
 164                                strbuf_addf(&path, "\t%s\n", rejects->items[i].string);
 165                        error(ERRORMSG(o, e), path.buf);
 166                        strbuf_release(&path);
 167                }
 168                string_list_clear(rejects, 0);
 169        }
 170        if (something_displayed)
 171                fprintf(stderr, "Aborting\n");
 172}
 173
 174/*
 175 * Unlink the last component and schedule the leading directories for
 176 * removal, such that empty directories get removed.
 177 */
 178static void unlink_entry(const struct cache_entry *ce)
 179{
 180        if (!check_leading_path(ce->name, ce_namelen(ce)))
 181                return;
 182        if (remove_or_warn(ce->ce_mode, ce->name))
 183                return;
 184        schedule_dir_for_removal(ce->name, ce_namelen(ce));
 185}
 186
 187static struct checkout state;
 188static int check_updates(struct unpack_trees_options *o)
 189{
 190        unsigned cnt = 0, total = 0;
 191        struct progress *progress = NULL;
 192        struct index_state *index = &o->result;
 193        int i;
 194        int errs = 0;
 195
 196        if (o->update && o->verbose_update) {
 197                for (total = cnt = 0; cnt < index->cache_nr; cnt++) {
 198                        const struct cache_entry *ce = index->cache[cnt];
 199                        if (ce->ce_flags & (CE_UPDATE | CE_WT_REMOVE))
 200                                total++;
 201                }
 202
 203                progress = start_progress_delay(_("Checking out files"),
 204                                                total, 50, 1);
 205                cnt = 0;
 206        }
 207
 208        if (o->update)
 209                git_attr_set_direction(GIT_ATTR_CHECKOUT, &o->result);
 210        for (i = 0; i < index->cache_nr; i++) {
 211                const struct cache_entry *ce = index->cache[i];
 212
 213                if (ce->ce_flags & CE_WT_REMOVE) {
 214                        display_progress(progress, ++cnt);
 215                        if (o->update && !o->dry_run)
 216                                unlink_entry(ce);
 217                        continue;
 218                }
 219        }
 220        remove_marked_cache_entries(&o->result);
 221        remove_scheduled_dirs();
 222
 223        for (i = 0; i < index->cache_nr; i++) {
 224                struct cache_entry *ce = index->cache[i];
 225
 226                if (ce->ce_flags & CE_UPDATE) {
 227                        if (ce->ce_flags & CE_WT_REMOVE)
 228                                die("BUG: both update and delete flags are set on %s",
 229                                    ce->name);
 230                        display_progress(progress, ++cnt);
 231                        ce->ce_flags &= ~CE_UPDATE;
 232                        if (o->update && !o->dry_run) {
 233                                errs |= checkout_entry(ce, &state, NULL);
 234                        }
 235                }
 236        }
 237        stop_progress(&progress);
 238        if (o->update)
 239                git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
 240        return errs != 0;
 241}
 242
 243static int verify_uptodate_sparse(const struct cache_entry *ce,
 244                                  struct unpack_trees_options *o);
 245static int verify_absent_sparse(const struct cache_entry *ce,
 246                                enum unpack_trees_error_types,
 247                                struct unpack_trees_options *o);
 248
 249static int apply_sparse_checkout(struct index_state *istate,
 250                                 struct cache_entry *ce,
 251                                 struct unpack_trees_options *o)
 252{
 253        int was_skip_worktree = ce_skip_worktree(ce);
 254
 255        if (ce->ce_flags & CE_NEW_SKIP_WORKTREE)
 256                ce->ce_flags |= CE_SKIP_WORKTREE;
 257        else
 258                ce->ce_flags &= ~CE_SKIP_WORKTREE;
 259        if (was_skip_worktree != ce_skip_worktree(ce)) {
 260                ce->ce_flags |= CE_UPDATE_IN_BASE;
 261                istate->cache_changed |= CE_ENTRY_CHANGED;
 262        }
 263
 264        /*
 265         * if (!was_skip_worktree && !ce_skip_worktree()) {
 266         *      This is perfectly normal. Move on;
 267         * }
 268         */
 269
 270        /*
 271         * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
 272         * area as a result of ce_skip_worktree() shortcuts in
 273         * verify_absent() and verify_uptodate().
 274         * Make sure they don't modify worktree if they are already
 275         * outside checkout area
 276         */
 277        if (was_skip_worktree && ce_skip_worktree(ce)) {
 278                ce->ce_flags &= ~CE_UPDATE;
 279
 280                /*
 281                 * By default, when CE_REMOVE is on, CE_WT_REMOVE is also
 282                 * on to get that file removed from both index and worktree.
 283                 * If that file is already outside worktree area, don't
 284                 * bother remove it.
 285                 */
 286                if (ce->ce_flags & CE_REMOVE)
 287                        ce->ce_flags &= ~CE_WT_REMOVE;
 288        }
 289
 290        if (!was_skip_worktree && ce_skip_worktree(ce)) {
 291                /*
 292                 * If CE_UPDATE is set, verify_uptodate() must be called already
 293                 * also stat info may have lost after merged_entry() so calling
 294                 * verify_uptodate() again may fail
 295                 */
 296                if (!(ce->ce_flags & CE_UPDATE) && verify_uptodate_sparse(ce, o))
 297                        return -1;
 298                ce->ce_flags |= CE_WT_REMOVE;
 299                ce->ce_flags &= ~CE_UPDATE;
 300        }
 301        if (was_skip_worktree && !ce_skip_worktree(ce)) {
 302                if (verify_absent_sparse(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o))
 303                        return -1;
 304                ce->ce_flags |= CE_UPDATE;
 305        }
 306        return 0;
 307}
 308
 309static inline int call_unpack_fn(const struct cache_entry * const *src,
 310                                 struct unpack_trees_options *o)
 311{
 312        int ret = o->fn(src, o);
 313        if (ret > 0)
 314                ret = 0;
 315        return ret;
 316}
 317
 318static void mark_ce_used(struct cache_entry *ce, struct unpack_trees_options *o)
 319{
 320        ce->ce_flags |= CE_UNPACKED;
 321
 322        if (o->cache_bottom < o->src_index->cache_nr &&
 323            o->src_index->cache[o->cache_bottom] == ce) {
 324                int bottom = o->cache_bottom;
 325                while (bottom < o->src_index->cache_nr &&
 326                       o->src_index->cache[bottom]->ce_flags & CE_UNPACKED)
 327                        bottom++;
 328                o->cache_bottom = bottom;
 329        }
 330}
 331
 332static void mark_all_ce_unused(struct index_state *index)
 333{
 334        int i;
 335        for (i = 0; i < index->cache_nr; i++)
 336                index->cache[i]->ce_flags &= ~(CE_UNPACKED | CE_ADDED | CE_NEW_SKIP_WORKTREE);
 337}
 338
 339static int locate_in_src_index(const struct cache_entry *ce,
 340                               struct unpack_trees_options *o)
 341{
 342        struct index_state *index = o->src_index;
 343        int len = ce_namelen(ce);
 344        int pos = index_name_pos(index, ce->name, len);
 345        if (pos < 0)
 346                pos = -1 - pos;
 347        return pos;
 348}
 349
 350/*
 351 * We call unpack_index_entry() with an unmerged cache entry
 352 * only in diff-index, and it wants a single callback.  Skip
 353 * the other unmerged entry with the same name.
 354 */
 355static void mark_ce_used_same_name(struct cache_entry *ce,
 356                                   struct unpack_trees_options *o)
 357{
 358        struct index_state *index = o->src_index;
 359        int len = ce_namelen(ce);
 360        int pos;
 361
 362        for (pos = locate_in_src_index(ce, o); pos < index->cache_nr; pos++) {
 363                struct cache_entry *next = index->cache[pos];
 364                if (len != ce_namelen(next) ||
 365                    memcmp(ce->name, next->name, len))
 366                        break;
 367                mark_ce_used(next, o);
 368        }
 369}
 370
 371static struct cache_entry *next_cache_entry(struct unpack_trees_options *o)
 372{
 373        const struct index_state *index = o->src_index;
 374        int pos = o->cache_bottom;
 375
 376        while (pos < index->cache_nr) {
 377                struct cache_entry *ce = index->cache[pos];
 378                if (!(ce->ce_flags & CE_UNPACKED))
 379                        return ce;
 380                pos++;
 381        }
 382        return NULL;
 383}
 384
 385static void add_same_unmerged(const struct cache_entry *ce,
 386                              struct unpack_trees_options *o)
 387{
 388        struct index_state *index = o->src_index;
 389        int len = ce_namelen(ce);
 390        int pos = index_name_pos(index, ce->name, len);
 391
 392        if (0 <= pos)
 393                die("programming error in a caller of mark_ce_used_same_name");
 394        for (pos = -pos - 1; pos < index->cache_nr; pos++) {
 395                struct cache_entry *next = index->cache[pos];
 396                if (len != ce_namelen(next) ||
 397                    memcmp(ce->name, next->name, len))
 398                        break;
 399                add_entry(o, next, 0, 0);
 400                mark_ce_used(next, o);
 401        }
 402}
 403
 404static int unpack_index_entry(struct cache_entry *ce,
 405                              struct unpack_trees_options *o)
 406{
 407        const struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 408        int ret;
 409
 410        src[0] = ce;
 411
 412        mark_ce_used(ce, o);
 413        if (ce_stage(ce)) {
 414                if (o->skip_unmerged) {
 415                        add_entry(o, ce, 0, 0);
 416                        return 0;
 417                }
 418        }
 419        ret = call_unpack_fn(src, o);
 420        if (ce_stage(ce))
 421                mark_ce_used_same_name(ce, o);
 422        return ret;
 423}
 424
 425static int find_cache_pos(struct traverse_info *, const struct name_entry *);
 426
 427static void restore_cache_bottom(struct traverse_info *info, int bottom)
 428{
 429        struct unpack_trees_options *o = info->data;
 430
 431        if (o->diff_index_cached)
 432                return;
 433        o->cache_bottom = bottom;
 434}
 435
 436static int switch_cache_bottom(struct traverse_info *info)
 437{
 438        struct unpack_trees_options *o = info->data;
 439        int ret, pos;
 440
 441        if (o->diff_index_cached)
 442                return 0;
 443        ret = o->cache_bottom;
 444        pos = find_cache_pos(info->prev, &info->name);
 445
 446        if (pos < -1)
 447                o->cache_bottom = -2 - pos;
 448        else if (pos < 0)
 449                o->cache_bottom = o->src_index->cache_nr;
 450        return ret;
 451}
 452
 453static int traverse_trees_recursive(int n, unsigned long dirmask,
 454                                    unsigned long df_conflicts,
 455                                    struct name_entry *names,
 456                                    struct traverse_info *info)
 457{
 458        int i, ret, bottom;
 459        struct tree_desc t[MAX_UNPACK_TREES];
 460        void *buf[MAX_UNPACK_TREES];
 461        struct traverse_info newinfo;
 462        struct name_entry *p;
 463
 464        p = names;
 465        while (!p->mode)
 466                p++;
 467
 468        newinfo = *info;
 469        newinfo.prev = info;
 470        newinfo.pathspec = info->pathspec;
 471        newinfo.name = *p;
 472        newinfo.pathlen += tree_entry_len(p) + 1;
 473        newinfo.df_conflicts |= df_conflicts;
 474
 475        for (i = 0; i < n; i++, dirmask >>= 1) {
 476                const unsigned char *sha1 = NULL;
 477                if (dirmask & 1)
 478                        sha1 = names[i].sha1;
 479                buf[i] = fill_tree_descriptor(t+i, sha1);
 480        }
 481
 482        bottom = switch_cache_bottom(&newinfo);
 483        ret = traverse_trees(n, t, &newinfo);
 484        restore_cache_bottom(&newinfo, bottom);
 485
 486        for (i = 0; i < n; i++)
 487                free(buf[i]);
 488
 489        return ret;
 490}
 491
 492/*
 493 * Compare the traverse-path to the cache entry without actually
 494 * having to generate the textual representation of the traverse
 495 * path.
 496 *
 497 * NOTE! This *only* compares up to the size of the traverse path
 498 * itself - the caller needs to do the final check for the cache
 499 * entry having more data at the end!
 500 */
 501static int do_compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 502{
 503        int len, pathlen, ce_len;
 504        const char *ce_name;
 505
 506        if (info->prev) {
 507                int cmp = do_compare_entry(ce, info->prev, &info->name);
 508                if (cmp)
 509                        return cmp;
 510        }
 511        pathlen = info->pathlen;
 512        ce_len = ce_namelen(ce);
 513
 514        /* If ce_len < pathlen then we must have previously hit "name == directory" entry */
 515        if (ce_len < pathlen)
 516                return -1;
 517
 518        ce_len -= pathlen;
 519        ce_name = ce->name + pathlen;
 520
 521        len = tree_entry_len(n);
 522        return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 523}
 524
 525static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 526{
 527        int cmp = do_compare_entry(ce, info, n);
 528        if (cmp)
 529                return cmp;
 530
 531        /*
 532         * Even if the beginning compared identically, the ce should
 533         * compare as bigger than a directory leading up to it!
 534         */
 535        return ce_namelen(ce) > traverse_path_len(info, n);
 536}
 537
 538static int ce_in_traverse_path(const struct cache_entry *ce,
 539                               const struct traverse_info *info)
 540{
 541        if (!info->prev)
 542                return 1;
 543        if (do_compare_entry(ce, info->prev, &info->name))
 544                return 0;
 545        /*
 546         * If ce (blob) is the same name as the path (which is a tree
 547         * we will be descending into), it won't be inside it.
 548         */
 549        return (info->pathlen < ce_namelen(ce));
 550}
 551
 552static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
 553{
 554        int len = traverse_path_len(info, n);
 555        struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
 556
 557        ce->ce_mode = create_ce_mode(n->mode);
 558        ce->ce_flags = create_ce_flags(stage);
 559        ce->ce_namelen = len;
 560        hashcpy(ce->sha1, n->sha1);
 561        make_traverse_path(ce->name, info, n);
 562
 563        return ce;
 564}
 565
 566static int unpack_nondirectories(int n, unsigned long mask,
 567                                 unsigned long dirmask,
 568                                 struct cache_entry **src,
 569                                 const struct name_entry *names,
 570                                 const struct traverse_info *info)
 571{
 572        int i;
 573        struct unpack_trees_options *o = info->data;
 574        unsigned long conflicts = info->df_conflicts | dirmask;
 575
 576        /* Do we have *only* directories? Nothing to do */
 577        if (mask == dirmask && !src[0])
 578                return 0;
 579
 580        /*
 581         * Ok, we've filled in up to any potential index entry in src[0],
 582         * now do the rest.
 583         */
 584        for (i = 0; i < n; i++) {
 585                int stage;
 586                unsigned int bit = 1ul << i;
 587                if (conflicts & bit) {
 588                        src[i + o->merge] = o->df_conflict_entry;
 589                        continue;
 590                }
 591                if (!(mask & bit))
 592                        continue;
 593                if (!o->merge)
 594                        stage = 0;
 595                else if (i + 1 < o->head_idx)
 596                        stage = 1;
 597                else if (i + 1 > o->head_idx)
 598                        stage = 3;
 599                else
 600                        stage = 2;
 601                src[i + o->merge] = create_ce_entry(info, names + i, stage);
 602        }
 603
 604        if (o->merge) {
 605                int rc = call_unpack_fn((const struct cache_entry * const *)src,
 606                                        o);
 607                for (i = 0; i < n; i++) {
 608                        struct cache_entry *ce = src[i + o->merge];
 609                        if (ce != o->df_conflict_entry)
 610                                free(ce);
 611                }
 612                return rc;
 613        }
 614
 615        for (i = 0; i < n; i++)
 616                if (src[i] && src[i] != o->df_conflict_entry)
 617                        if (do_add_entry(o, src[i], 0, 0))
 618                                return -1;
 619
 620        return 0;
 621}
 622
 623static int unpack_failed(struct unpack_trees_options *o, const char *message)
 624{
 625        discard_index(&o->result);
 626        if (!o->gently && !o->exiting_early) {
 627                if (message)
 628                        return error("%s", message);
 629                return -1;
 630        }
 631        return -1;
 632}
 633
 634/*
 635 * The tree traversal is looking at name p.  If we have a matching entry,
 636 * return it.  If name p is a directory in the index, do not return
 637 * anything, as we will want to match it when the traversal descends into
 638 * the directory.
 639 */
 640static int find_cache_pos(struct traverse_info *info,
 641                          const struct name_entry *p)
 642{
 643        int pos;
 644        struct unpack_trees_options *o = info->data;
 645        struct index_state *index = o->src_index;
 646        int pfxlen = info->pathlen;
 647        int p_len = tree_entry_len(p);
 648
 649        for (pos = o->cache_bottom; pos < index->cache_nr; pos++) {
 650                const struct cache_entry *ce = index->cache[pos];
 651                const char *ce_name, *ce_slash;
 652                int cmp, ce_len;
 653
 654                if (ce->ce_flags & CE_UNPACKED) {
 655                        /*
 656                         * cache_bottom entry is already unpacked, so
 657                         * we can never match it; don't check it
 658                         * again.
 659                         */
 660                        if (pos == o->cache_bottom)
 661                                ++o->cache_bottom;
 662                        continue;
 663                }
 664                if (!ce_in_traverse_path(ce, info))
 665                        continue;
 666                ce_name = ce->name + pfxlen;
 667                ce_slash = strchr(ce_name, '/');
 668                if (ce_slash)
 669                        ce_len = ce_slash - ce_name;
 670                else
 671                        ce_len = ce_namelen(ce) - pfxlen;
 672                cmp = name_compare(p->path, p_len, ce_name, ce_len);
 673                /*
 674                 * Exact match; if we have a directory we need to
 675                 * delay returning it.
 676                 */
 677                if (!cmp)
 678                        return ce_slash ? -2 - pos : pos;
 679                if (0 < cmp)
 680                        continue; /* keep looking */
 681                /*
 682                 * ce_name sorts after p->path; could it be that we
 683                 * have files under p->path directory in the index?
 684                 * E.g.  ce_name == "t-i", and p->path == "t"; we may
 685                 * have "t/a" in the index.
 686                 */
 687                if (p_len < ce_len && !memcmp(ce_name, p->path, p_len) &&
 688                    ce_name[p_len] < '/')
 689                        continue; /* keep looking */
 690                break;
 691        }
 692        return -1;
 693}
 694
 695static struct cache_entry *find_cache_entry(struct traverse_info *info,
 696                                            const struct name_entry *p)
 697{
 698        int pos = find_cache_pos(info, p);
 699        struct unpack_trees_options *o = info->data;
 700
 701        if (0 <= pos)
 702                return o->src_index->cache[pos];
 703        else
 704                return NULL;
 705}
 706
 707static void debug_path(struct traverse_info *info)
 708{
 709        if (info->prev) {
 710                debug_path(info->prev);
 711                if (*info->prev->name.path)
 712                        putchar('/');
 713        }
 714        printf("%s", info->name.path);
 715}
 716
 717static void debug_name_entry(int i, struct name_entry *n)
 718{
 719        printf("ent#%d %06o %s\n", i,
 720               n->path ? n->mode : 0,
 721               n->path ? n->path : "(missing)");
 722}
 723
 724static void debug_unpack_callback(int n,
 725                                  unsigned long mask,
 726                                  unsigned long dirmask,
 727                                  struct name_entry *names,
 728                                  struct traverse_info *info)
 729{
 730        int i;
 731        printf("* unpack mask %lu, dirmask %lu, cnt %d ",
 732               mask, dirmask, n);
 733        debug_path(info);
 734        putchar('\n');
 735        for (i = 0; i < n; i++)
 736                debug_name_entry(i, names + i);
 737}
 738
 739static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
 740{
 741        struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 742        struct unpack_trees_options *o = info->data;
 743        const struct name_entry *p = names;
 744
 745        /* Find first entry with a real name (we could use "mask" too) */
 746        while (!p->mode)
 747                p++;
 748
 749        if (o->debug_unpack)
 750                debug_unpack_callback(n, mask, dirmask, names, info);
 751
 752        /* Are we supposed to look at the index too? */
 753        if (o->merge) {
 754                while (1) {
 755                        int cmp;
 756                        struct cache_entry *ce;
 757
 758                        if (o->diff_index_cached)
 759                                ce = next_cache_entry(o);
 760                        else
 761                                ce = find_cache_entry(info, p);
 762
 763                        if (!ce)
 764                                break;
 765                        cmp = compare_entry(ce, info, p);
 766                        if (cmp < 0) {
 767                                if (unpack_index_entry(ce, o) < 0)
 768                                        return unpack_failed(o, NULL);
 769                                continue;
 770                        }
 771                        if (!cmp) {
 772                                if (ce_stage(ce)) {
 773                                        /*
 774                                         * If we skip unmerged index
 775                                         * entries, we'll skip this
 776                                         * entry *and* the tree
 777                                         * entries associated with it!
 778                                         */
 779                                        if (o->skip_unmerged) {
 780                                                add_same_unmerged(ce, o);
 781                                                return mask;
 782                                        }
 783                                }
 784                                src[0] = ce;
 785                        }
 786                        break;
 787                }
 788        }
 789
 790        if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
 791                return -1;
 792
 793        if (o->merge && src[0]) {
 794                if (ce_stage(src[0]))
 795                        mark_ce_used_same_name(src[0], o);
 796                else
 797                        mark_ce_used(src[0], o);
 798        }
 799
 800        /* Now handle any directories.. */
 801        if (dirmask) {
 802                /* special case: "diff-index --cached" looking at a tree */
 803                if (o->diff_index_cached &&
 804                    n == 1 && dirmask == 1 && S_ISDIR(names->mode)) {
 805                        int matches;
 806                        matches = cache_tree_matches_traversal(o->src_index->cache_tree,
 807                                                               names, info);
 808                        /*
 809                         * Everything under the name matches; skip the
 810                         * entire hierarchy.  diff_index_cached codepath
 811                         * special cases D/F conflicts in such a way that
 812                         * it does not do any look-ahead, so this is safe.
 813                         */
 814                        if (matches) {
 815                                o->cache_bottom += matches;
 816                                return mask;
 817                        }
 818                }
 819
 820                if (traverse_trees_recursive(n, dirmask, mask & ~dirmask,
 821                                             names, info) < 0)
 822                        return -1;
 823                return mask;
 824        }
 825
 826        return mask;
 827}
 828
 829static int clear_ce_flags_1(struct cache_entry **cache, int nr,
 830                            struct strbuf *prefix,
 831                            int select_mask, int clear_mask,
 832                            struct exclude_list *el, int defval);
 833
 834/* Whole directory matching */
 835static int clear_ce_flags_dir(struct cache_entry **cache, int nr,
 836                              struct strbuf *prefix,
 837                              char *basename,
 838                              int select_mask, int clear_mask,
 839                              struct exclude_list *el, int defval)
 840{
 841        struct cache_entry **cache_end;
 842        int dtype = DT_DIR;
 843        int ret = is_excluded_from_list(prefix->buf, prefix->len,
 844                                        basename, &dtype, el);
 845        int rc;
 846
 847        strbuf_addch(prefix, '/');
 848
 849        /* If undecided, use matching result of parent dir in defval */
 850        if (ret < 0)
 851                ret = defval;
 852
 853        for (cache_end = cache; cache_end != cache + nr; cache_end++) {
 854                struct cache_entry *ce = *cache_end;
 855                if (strncmp(ce->name, prefix->buf, prefix->len))
 856                        break;
 857        }
 858
 859        /*
 860         * TODO: check el, if there are no patterns that may conflict
 861         * with ret (iow, we know in advance the incl/excl
 862         * decision for the entire directory), clear flag here without
 863         * calling clear_ce_flags_1(). That function will call
 864         * the expensive is_excluded_from_list() on every entry.
 865         */
 866        rc = clear_ce_flags_1(cache, cache_end - cache,
 867                              prefix,
 868                              select_mask, clear_mask,
 869                              el, ret);
 870        strbuf_setlen(prefix, prefix->len - 1);
 871        return rc;
 872}
 873
 874/*
 875 * Traverse the index, find every entry that matches according to
 876 * o->el. Do "ce_flags &= ~clear_mask" on those entries. Return the
 877 * number of traversed entries.
 878 *
 879 * If select_mask is non-zero, only entries whose ce_flags has on of
 880 * those bits enabled are traversed.
 881 *
 882 * cache        : pointer to an index entry
 883 * prefix_len   : an offset to its path
 884 *
 885 * The current path ("prefix") including the trailing '/' is
 886 *   cache[0]->name[0..(prefix_len-1)]
 887 * Top level path has prefix_len zero.
 888 */
 889static int clear_ce_flags_1(struct cache_entry **cache, int nr,
 890                            struct strbuf *prefix,
 891                            int select_mask, int clear_mask,
 892                            struct exclude_list *el, int defval)
 893{
 894        struct cache_entry **cache_end = cache + nr;
 895
 896        /*
 897         * Process all entries that have the given prefix and meet
 898         * select_mask condition
 899         */
 900        while(cache != cache_end) {
 901                struct cache_entry *ce = *cache;
 902                const char *name, *slash;
 903                int len, dtype, ret;
 904
 905                if (select_mask && !(ce->ce_flags & select_mask)) {
 906                        cache++;
 907                        continue;
 908                }
 909
 910                if (prefix->len && strncmp(ce->name, prefix->buf, prefix->len))
 911                        break;
 912
 913                name = ce->name + prefix->len;
 914                slash = strchr(name, '/');
 915
 916                /* If it's a directory, try whole directory match first */
 917                if (slash) {
 918                        int processed;
 919
 920                        len = slash - name;
 921                        strbuf_add(prefix, name, len);
 922
 923                        processed = clear_ce_flags_dir(cache, cache_end - cache,
 924                                                       prefix,
 925                                                       prefix->buf + prefix->len - len,
 926                                                       select_mask, clear_mask,
 927                                                       el, defval);
 928
 929                        /* clear_c_f_dir eats a whole dir already? */
 930                        if (processed) {
 931                                cache += processed;
 932                                strbuf_setlen(prefix, prefix->len - len);
 933                                continue;
 934                        }
 935
 936                        strbuf_addch(prefix, '/');
 937                        cache += clear_ce_flags_1(cache, cache_end - cache,
 938                                                  prefix,
 939                                                  select_mask, clear_mask, el, defval);
 940                        strbuf_setlen(prefix, prefix->len - len - 1);
 941                        continue;
 942                }
 943
 944                /* Non-directory */
 945                dtype = ce_to_dtype(ce);
 946                ret = is_excluded_from_list(ce->name, ce_namelen(ce),
 947                                            name, &dtype, el);
 948                if (ret < 0)
 949                        ret = defval;
 950                if (ret > 0)
 951                        ce->ce_flags &= ~clear_mask;
 952                cache++;
 953        }
 954        return nr - (cache_end - cache);
 955}
 956
 957static int clear_ce_flags(struct cache_entry **cache, int nr,
 958                            int select_mask, int clear_mask,
 959                            struct exclude_list *el)
 960{
 961        static struct strbuf prefix = STRBUF_INIT;
 962
 963        strbuf_reset(&prefix);
 964
 965        return clear_ce_flags_1(cache, nr,
 966                                &prefix,
 967                                select_mask, clear_mask,
 968                                el, 0);
 969}
 970
 971/*
 972 * Set/Clear CE_NEW_SKIP_WORKTREE according to $GIT_DIR/info/sparse-checkout
 973 */
 974static void mark_new_skip_worktree(struct exclude_list *el,
 975                                   struct index_state *the_index,
 976                                   int select_flag, int skip_wt_flag)
 977{
 978        int i;
 979
 980        /*
 981         * 1. Pretend the narrowest worktree: only unmerged entries
 982         * are checked out
 983         */
 984        for (i = 0; i < the_index->cache_nr; i++) {
 985                struct cache_entry *ce = the_index->cache[i];
 986
 987                if (select_flag && !(ce->ce_flags & select_flag))
 988                        continue;
 989
 990                if (!ce_stage(ce))
 991                        ce->ce_flags |= skip_wt_flag;
 992                else
 993                        ce->ce_flags &= ~skip_wt_flag;
 994        }
 995
 996        /*
 997         * 2. Widen worktree according to sparse-checkout file.
 998         * Matched entries will have skip_wt_flag cleared (i.e. "in")
 999         */
1000        clear_ce_flags(the_index->cache, the_index->cache_nr,
1001                       select_flag, skip_wt_flag, el);
1002}
1003
1004static int verify_absent(const struct cache_entry *,
1005                         enum unpack_trees_error_types,
1006                         struct unpack_trees_options *);
1007/*
1008 * N-way merge "len" trees.  Returns 0 on success, -1 on failure to manipulate the
1009 * resulting index, -2 on failure to reflect the changes to the work tree.
1010 *
1011 * CE_ADDED, CE_UNPACKED and CE_NEW_SKIP_WORKTREE are used internally
1012 */
1013int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
1014{
1015        int i, ret;
1016        static struct cache_entry *dfc;
1017        struct exclude_list el;
1018
1019        if (len > MAX_UNPACK_TREES)
1020                die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
1021        memset(&state, 0, sizeof(state));
1022        state.base_dir = "";
1023        state.force = 1;
1024        state.quiet = 1;
1025        state.refresh_cache = 1;
1026        state.istate = &o->result;
1027
1028        memset(&el, 0, sizeof(el));
1029        if (!core_apply_sparse_checkout || !o->update)
1030                o->skip_sparse_checkout = 1;
1031        if (!o->skip_sparse_checkout) {
1032                char *sparse = git_pathdup("info/sparse-checkout");
1033                if (add_excludes_from_file_to_list(sparse, "", 0, &el, 0) < 0)
1034                        o->skip_sparse_checkout = 1;
1035                else
1036                        o->el = &el;
1037                free(sparse);
1038        }
1039
1040        memset(&o->result, 0, sizeof(o->result));
1041        o->result.initialized = 1;
1042        o->result.timestamp.sec = o->src_index->timestamp.sec;
1043        o->result.timestamp.nsec = o->src_index->timestamp.nsec;
1044        o->result.version = o->src_index->version;
1045        o->result.split_index = o->src_index->split_index;
1046        if (o->result.split_index)
1047                o->result.split_index->refcount++;
1048        hashcpy(o->result.sha1, o->src_index->sha1);
1049        o->merge_size = len;
1050        mark_all_ce_unused(o->src_index);
1051
1052        /*
1053         * Sparse checkout loop #1: set NEW_SKIP_WORKTREE on existing entries
1054         */
1055        if (!o->skip_sparse_checkout)
1056                mark_new_skip_worktree(o->el, o->src_index, 0, CE_NEW_SKIP_WORKTREE);
1057
1058        if (!dfc)
1059                dfc = xcalloc(1, cache_entry_size(0));
1060        o->df_conflict_entry = dfc;
1061
1062        if (len) {
1063                const char *prefix = o->prefix ? o->prefix : "";
1064                struct traverse_info info;
1065
1066                setup_traverse_info(&info, prefix);
1067                info.fn = unpack_callback;
1068                info.data = o;
1069                info.show_all_errors = o->show_all_errors;
1070                info.pathspec = o->pathspec;
1071
1072                if (o->prefix) {
1073                        /*
1074                         * Unpack existing index entries that sort before the
1075                         * prefix the tree is spliced into.  Note that o->merge
1076                         * is always true in this case.
1077                         */
1078                        while (1) {
1079                                struct cache_entry *ce = next_cache_entry(o);
1080                                if (!ce)
1081                                        break;
1082                                if (ce_in_traverse_path(ce, &info))
1083                                        break;
1084                                if (unpack_index_entry(ce, o) < 0)
1085                                        goto return_failed;
1086                        }
1087                }
1088
1089                if (traverse_trees(len, t, &info) < 0)
1090                        goto return_failed;
1091        }
1092
1093        /* Any left-over entries in the index? */
1094        if (o->merge) {
1095                while (1) {
1096                        struct cache_entry *ce = next_cache_entry(o);
1097                        if (!ce)
1098                                break;
1099                        if (unpack_index_entry(ce, o) < 0)
1100                                goto return_failed;
1101                }
1102        }
1103        mark_all_ce_unused(o->src_index);
1104
1105        if (o->trivial_merges_only && o->nontrivial_merge) {
1106                ret = unpack_failed(o, "Merge requires file-level merging");
1107                goto done;
1108        }
1109
1110        if (!o->skip_sparse_checkout) {
1111                int empty_worktree = 1;
1112
1113                /*
1114                 * Sparse checkout loop #2: set NEW_SKIP_WORKTREE on entries not in loop #1
1115                 * If the will have NEW_SKIP_WORKTREE, also set CE_SKIP_WORKTREE
1116                 * so apply_sparse_checkout() won't attempt to remove it from worktree
1117                 */
1118                mark_new_skip_worktree(o->el, &o->result, CE_ADDED, CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1119
1120                ret = 0;
1121                for (i = 0; i < o->result.cache_nr; i++) {
1122                        struct cache_entry *ce = o->result.cache[i];
1123
1124                        /*
1125                         * Entries marked with CE_ADDED in merged_entry() do not have
1126                         * verify_absent() check (the check is effectively disabled
1127                         * because CE_NEW_SKIP_WORKTREE is set unconditionally).
1128                         *
1129                         * Do the real check now because we have had
1130                         * correct CE_NEW_SKIP_WORKTREE
1131                         */
1132                        if (ce->ce_flags & CE_ADDED &&
1133                            verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1134                                if (!o->show_all_errors)
1135                                        goto return_failed;
1136                                ret = -1;
1137                        }
1138
1139                        if (apply_sparse_checkout(&o->result, ce, o)) {
1140                                if (!o->show_all_errors)
1141                                        goto return_failed;
1142                                ret = -1;
1143                        }
1144                        if (!ce_skip_worktree(ce))
1145                                empty_worktree = 0;
1146
1147                }
1148                if (ret < 0)
1149                        goto return_failed;
1150                /*
1151                 * Sparse checkout is meant to narrow down checkout area
1152                 * but it does not make sense to narrow down to empty working
1153                 * tree. This is usually a mistake in sparse checkout rules.
1154                 * Do not allow users to do that.
1155                 */
1156                if (o->result.cache_nr && empty_worktree) {
1157                        ret = unpack_failed(o, "Sparse checkout leaves no entry on working directory");
1158                        goto done;
1159                }
1160        }
1161
1162        o->src_index = NULL;
1163        ret = check_updates(o) ? (-2) : 0;
1164        if (o->dst_index) {
1165                if (!ret) {
1166                        if (!o->result.cache_tree)
1167                                o->result.cache_tree = cache_tree();
1168                        if (!cache_tree_fully_valid(o->result.cache_tree))
1169                                cache_tree_update(&o->result,
1170                                                  WRITE_TREE_SILENT |
1171                                                  WRITE_TREE_REPAIR);
1172                }
1173                discard_index(o->dst_index);
1174                *o->dst_index = o->result;
1175        } else {
1176                discard_index(&o->result);
1177        }
1178
1179done:
1180        clear_exclude_list(&el);
1181        return ret;
1182
1183return_failed:
1184        if (o->show_all_errors)
1185                display_error_msgs(o);
1186        mark_all_ce_unused(o->src_index);
1187        ret = unpack_failed(o, NULL);
1188        if (o->exiting_early)
1189                ret = 0;
1190        goto done;
1191}
1192
1193/* Here come the merge functions */
1194
1195static int reject_merge(const struct cache_entry *ce,
1196                        struct unpack_trees_options *o)
1197{
1198        return o->gently ? -1 :
1199                add_rejected_path(o, ERROR_WOULD_OVERWRITE, ce->name);
1200}
1201
1202static int same(const struct cache_entry *a, const struct cache_entry *b)
1203{
1204        if (!!a != !!b)
1205                return 0;
1206        if (!a && !b)
1207                return 1;
1208        if ((a->ce_flags | b->ce_flags) & CE_CONFLICTED)
1209                return 0;
1210        return a->ce_mode == b->ce_mode &&
1211               !hashcmp(a->sha1, b->sha1);
1212}
1213
1214
1215/*
1216 * When a CE gets turned into an unmerged entry, we
1217 * want it to be up-to-date
1218 */
1219static int verify_uptodate_1(const struct cache_entry *ce,
1220                             struct unpack_trees_options *o,
1221                             enum unpack_trees_error_types error_type)
1222{
1223        struct stat st;
1224
1225        if (o->index_only)
1226                return 0;
1227
1228        /*
1229         * CE_VALID and CE_SKIP_WORKTREE cheat, we better check again
1230         * if this entry is truly up-to-date because this file may be
1231         * overwritten.
1232         */
1233        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
1234                ; /* keep checking */
1235        else if (o->reset || ce_uptodate(ce))
1236                return 0;
1237
1238        if (!lstat(ce->name, &st)) {
1239                int flags = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE;
1240                unsigned changed = ie_match_stat(o->src_index, ce, &st, flags);
1241                if (!changed)
1242                        return 0;
1243                /*
1244                 * NEEDSWORK: the current default policy is to allow
1245                 * submodule to be out of sync wrt the superproject
1246                 * index.  This needs to be tightened later for
1247                 * submodules that are marked to be automatically
1248                 * checked out.
1249                 */
1250                if (S_ISGITLINK(ce->ce_mode))
1251                        return 0;
1252                errno = 0;
1253        }
1254        if (errno == ENOENT)
1255                return 0;
1256        return o->gently ? -1 :
1257                add_rejected_path(o, error_type, ce->name);
1258}
1259
1260static int verify_uptodate(const struct cache_entry *ce,
1261                           struct unpack_trees_options *o)
1262{
1263        if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1264                return 0;
1265        return verify_uptodate_1(ce, o, ERROR_NOT_UPTODATE_FILE);
1266}
1267
1268static int verify_uptodate_sparse(const struct cache_entry *ce,
1269                                  struct unpack_trees_options *o)
1270{
1271        return verify_uptodate_1(ce, o, ERROR_SPARSE_NOT_UPTODATE_FILE);
1272}
1273
1274static void invalidate_ce_path(const struct cache_entry *ce,
1275                               struct unpack_trees_options *o)
1276{
1277        if (!ce)
1278                return;
1279        cache_tree_invalidate_path(o->src_index, ce->name);
1280        untracked_cache_invalidate_path(o->src_index, ce->name);
1281}
1282
1283/*
1284 * Check that checking out ce->sha1 in subdir ce->name is not
1285 * going to overwrite any working files.
1286 *
1287 * Currently, git does not checkout subprojects during a superproject
1288 * checkout, so it is not going to overwrite anything.
1289 */
1290static int verify_clean_submodule(const struct cache_entry *ce,
1291                                  enum unpack_trees_error_types error_type,
1292                                  struct unpack_trees_options *o)
1293{
1294        return 0;
1295}
1296
1297static int verify_clean_subdirectory(const struct cache_entry *ce,
1298                                     enum unpack_trees_error_types error_type,
1299                                     struct unpack_trees_options *o)
1300{
1301        /*
1302         * we are about to extract "ce->name"; we would not want to lose
1303         * anything in the existing directory there.
1304         */
1305        int namelen;
1306        int i;
1307        struct dir_struct d;
1308        char *pathbuf;
1309        int cnt = 0;
1310        unsigned char sha1[20];
1311
1312        if (S_ISGITLINK(ce->ce_mode) &&
1313            resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
1314                /* If we are not going to update the submodule, then
1315                 * we don't care.
1316                 */
1317                if (!hashcmp(sha1, ce->sha1))
1318                        return 0;
1319                return verify_clean_submodule(ce, error_type, o);
1320        }
1321
1322        /*
1323         * First let's make sure we do not have a local modification
1324         * in that directory.
1325         */
1326        namelen = ce_namelen(ce);
1327        for (i = locate_in_src_index(ce, o);
1328             i < o->src_index->cache_nr;
1329             i++) {
1330                struct cache_entry *ce2 = o->src_index->cache[i];
1331                int len = ce_namelen(ce2);
1332                if (len < namelen ||
1333                    strncmp(ce->name, ce2->name, namelen) ||
1334                    ce2->name[namelen] != '/')
1335                        break;
1336                /*
1337                 * ce2->name is an entry in the subdirectory to be
1338                 * removed.
1339                 */
1340                if (!ce_stage(ce2)) {
1341                        if (verify_uptodate(ce2, o))
1342                                return -1;
1343                        add_entry(o, ce2, CE_REMOVE, 0);
1344                        mark_ce_used(ce2, o);
1345                }
1346                cnt++;
1347        }
1348
1349        /*
1350         * Then we need to make sure that we do not lose a locally
1351         * present file that is not ignored.
1352         */
1353        pathbuf = xstrfmt("%.*s/", namelen, ce->name);
1354
1355        memset(&d, 0, sizeof(d));
1356        if (o->dir)
1357                d.exclude_per_dir = o->dir->exclude_per_dir;
1358        i = read_directory(&d, pathbuf, namelen+1, NULL);
1359        if (i)
1360                return o->gently ? -1 :
1361                        add_rejected_path(o, ERROR_NOT_UPTODATE_DIR, ce->name);
1362        free(pathbuf);
1363        return cnt;
1364}
1365
1366/*
1367 * This gets called when there was no index entry for the tree entry 'dst',
1368 * but we found a file in the working tree that 'lstat()' said was fine,
1369 * and we're on a case-insensitive filesystem.
1370 *
1371 * See if we can find a case-insensitive match in the index that also
1372 * matches the stat information, and assume it's that other file!
1373 */
1374static int icase_exists(struct unpack_trees_options *o, const char *name, int len, struct stat *st)
1375{
1376        const struct cache_entry *src;
1377
1378        src = index_file_exists(o->src_index, name, len, 1);
1379        return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
1380}
1381
1382static int check_ok_to_remove(const char *name, int len, int dtype,
1383                              const struct cache_entry *ce, struct stat *st,
1384                              enum unpack_trees_error_types error_type,
1385                              struct unpack_trees_options *o)
1386{
1387        const struct cache_entry *result;
1388
1389        /*
1390         * It may be that the 'lstat()' succeeded even though
1391         * target 'ce' was absent, because there is an old
1392         * entry that is different only in case..
1393         *
1394         * Ignore that lstat() if it matches.
1395         */
1396        if (ignore_case && icase_exists(o, name, len, st))
1397                return 0;
1398
1399        if (o->dir &&
1400            is_excluded(o->dir, name, &dtype))
1401                /*
1402                 * ce->name is explicitly excluded, so it is Ok to
1403                 * overwrite it.
1404                 */
1405                return 0;
1406        if (S_ISDIR(st->st_mode)) {
1407                /*
1408                 * We are checking out path "foo" and
1409                 * found "foo/." in the working tree.
1410                 * This is tricky -- if we have modified
1411                 * files that are in "foo/" we would lose
1412                 * them.
1413                 */
1414                if (verify_clean_subdirectory(ce, error_type, o) < 0)
1415                        return -1;
1416                return 0;
1417        }
1418
1419        /*
1420         * The previous round may already have decided to
1421         * delete this path, which is in a subdirectory that
1422         * is being replaced with a blob.
1423         */
1424        result = index_file_exists(&o->result, name, len, 0);
1425        if (result) {
1426                if (result->ce_flags & CE_REMOVE)
1427                        return 0;
1428        }
1429
1430        return o->gently ? -1 :
1431                add_rejected_path(o, error_type, name);
1432}
1433
1434/*
1435 * We do not want to remove or overwrite a working tree file that
1436 * is not tracked, unless it is ignored.
1437 */
1438static int verify_absent_1(const struct cache_entry *ce,
1439                           enum unpack_trees_error_types error_type,
1440                           struct unpack_trees_options *o)
1441{
1442        int len;
1443        struct stat st;
1444
1445        if (o->index_only || o->reset || !o->update)
1446                return 0;
1447
1448        len = check_leading_path(ce->name, ce_namelen(ce));
1449        if (!len)
1450                return 0;
1451        else if (len > 0) {
1452                char *path;
1453                int ret;
1454
1455                path = xmemdupz(ce->name, len);
1456                if (lstat(path, &st))
1457                        ret = error("cannot stat '%s': %s", path,
1458                                        strerror(errno));
1459                else
1460                        ret = check_ok_to_remove(path, len, DT_UNKNOWN, NULL,
1461                                                 &st, error_type, o);
1462                free(path);
1463                return ret;
1464        } else if (lstat(ce->name, &st)) {
1465                if (errno != ENOENT)
1466                        return error("cannot stat '%s': %s", ce->name,
1467                                     strerror(errno));
1468                return 0;
1469        } else {
1470                return check_ok_to_remove(ce->name, ce_namelen(ce),
1471                                          ce_to_dtype(ce), ce, &st,
1472                                          error_type, o);
1473        }
1474}
1475
1476static int verify_absent(const struct cache_entry *ce,
1477                         enum unpack_trees_error_types error_type,
1478                         struct unpack_trees_options *o)
1479{
1480        if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1481                return 0;
1482        return verify_absent_1(ce, error_type, o);
1483}
1484
1485static int verify_absent_sparse(const struct cache_entry *ce,
1486                                enum unpack_trees_error_types error_type,
1487                                struct unpack_trees_options *o)
1488{
1489        enum unpack_trees_error_types orphaned_error = error_type;
1490        if (orphaned_error == ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN)
1491                orphaned_error = ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN;
1492
1493        return verify_absent_1(ce, orphaned_error, o);
1494}
1495
1496static int merged_entry(const struct cache_entry *ce,
1497                        const struct cache_entry *old,
1498                        struct unpack_trees_options *o)
1499{
1500        int update = CE_UPDATE;
1501        struct cache_entry *merge = dup_entry(ce);
1502
1503        if (!old) {
1504                /*
1505                 * New index entries. In sparse checkout, the following
1506                 * verify_absent() will be delayed until after
1507                 * traverse_trees() finishes in unpack_trees(), then:
1508                 *
1509                 *  - CE_NEW_SKIP_WORKTREE will be computed correctly
1510                 *  - verify_absent() be called again, this time with
1511                 *    correct CE_NEW_SKIP_WORKTREE
1512                 *
1513                 * verify_absent() call here does nothing in sparse
1514                 * checkout (i.e. o->skip_sparse_checkout == 0)
1515                 */
1516                update |= CE_ADDED;
1517                merge->ce_flags |= CE_NEW_SKIP_WORKTREE;
1518
1519                if (verify_absent(merge,
1520                                  ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1521                        free(merge);
1522                        return -1;
1523                }
1524                invalidate_ce_path(merge, o);
1525        } else if (!(old->ce_flags & CE_CONFLICTED)) {
1526                /*
1527                 * See if we can re-use the old CE directly?
1528                 * That way we get the uptodate stat info.
1529                 *
1530                 * This also removes the UPDATE flag on a match; otherwise
1531                 * we will end up overwriting local changes in the work tree.
1532                 */
1533                if (same(old, merge)) {
1534                        copy_cache_entry(merge, old);
1535                        update = 0;
1536                } else {
1537                        if (verify_uptodate(old, o)) {
1538                                free(merge);
1539                                return -1;
1540                        }
1541                        /* Migrate old flags over */
1542                        update |= old->ce_flags & (CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1543                        invalidate_ce_path(old, o);
1544                }
1545        } else {
1546                /*
1547                 * Previously unmerged entry left as an existence
1548                 * marker by read_index_unmerged();
1549                 */
1550                invalidate_ce_path(old, o);
1551        }
1552
1553        do_add_entry(o, merge, update, CE_STAGEMASK);
1554        return 1;
1555}
1556
1557static int deleted_entry(const struct cache_entry *ce,
1558                         const struct cache_entry *old,
1559                         struct unpack_trees_options *o)
1560{
1561        /* Did it exist in the index? */
1562        if (!old) {
1563                if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1564                        return -1;
1565                return 0;
1566        }
1567        if (!(old->ce_flags & CE_CONFLICTED) && verify_uptodate(old, o))
1568                return -1;
1569        add_entry(o, ce, CE_REMOVE, 0);
1570        invalidate_ce_path(ce, o);
1571        return 1;
1572}
1573
1574static int keep_entry(const struct cache_entry *ce,
1575                      struct unpack_trees_options *o)
1576{
1577        add_entry(o, ce, 0, 0);
1578        return 1;
1579}
1580
1581#if DBRT_DEBUG
1582static void show_stage_entry(FILE *o,
1583                             const char *label, const struct cache_entry *ce)
1584{
1585        if (!ce)
1586                fprintf(o, "%s (missing)\n", label);
1587        else
1588                fprintf(o, "%s%06o %s %d\t%s\n",
1589                        label,
1590                        ce->ce_mode,
1591                        sha1_to_hex(ce->sha1),
1592                        ce_stage(ce),
1593                        ce->name);
1594}
1595#endif
1596
1597int threeway_merge(const struct cache_entry * const *stages,
1598                   struct unpack_trees_options *o)
1599{
1600        const struct cache_entry *index;
1601        const struct cache_entry *head;
1602        const struct cache_entry *remote = stages[o->head_idx + 1];
1603        int count;
1604        int head_match = 0;
1605        int remote_match = 0;
1606
1607        int df_conflict_head = 0;
1608        int df_conflict_remote = 0;
1609
1610        int any_anc_missing = 0;
1611        int no_anc_exists = 1;
1612        int i;
1613
1614        for (i = 1; i < o->head_idx; i++) {
1615                if (!stages[i] || stages[i] == o->df_conflict_entry)
1616                        any_anc_missing = 1;
1617                else
1618                        no_anc_exists = 0;
1619        }
1620
1621        index = stages[0];
1622        head = stages[o->head_idx];
1623
1624        if (head == o->df_conflict_entry) {
1625                df_conflict_head = 1;
1626                head = NULL;
1627        }
1628
1629        if (remote == o->df_conflict_entry) {
1630                df_conflict_remote = 1;
1631                remote = NULL;
1632        }
1633
1634        /*
1635         * First, if there's a #16 situation, note that to prevent #13
1636         * and #14.
1637         */
1638        if (!same(remote, head)) {
1639                for (i = 1; i < o->head_idx; i++) {
1640                        if (same(stages[i], head)) {
1641                                head_match = i;
1642                        }
1643                        if (same(stages[i], remote)) {
1644                                remote_match = i;
1645                        }
1646                }
1647        }
1648
1649        /*
1650         * We start with cases where the index is allowed to match
1651         * something other than the head: #14(ALT) and #2ALT, where it
1652         * is permitted to match the result instead.
1653         */
1654        /* #14, #14ALT, #2ALT */
1655        if (remote && !df_conflict_head && head_match && !remote_match) {
1656                if (index && !same(index, remote) && !same(index, head))
1657                        return reject_merge(index, o);
1658                return merged_entry(remote, index, o);
1659        }
1660        /*
1661         * If we have an entry in the index cache, then we want to
1662         * make sure that it matches head.
1663         */
1664        if (index && !same(index, head))
1665                return reject_merge(index, o);
1666
1667        if (head) {
1668                /* #5ALT, #15 */
1669                if (same(head, remote))
1670                        return merged_entry(head, index, o);
1671                /* #13, #3ALT */
1672                if (!df_conflict_remote && remote_match && !head_match)
1673                        return merged_entry(head, index, o);
1674        }
1675
1676        /* #1 */
1677        if (!head && !remote && any_anc_missing)
1678                return 0;
1679
1680        /*
1681         * Under the "aggressive" rule, we resolve mostly trivial
1682         * cases that we historically had git-merge-one-file resolve.
1683         */
1684        if (o->aggressive) {
1685                int head_deleted = !head;
1686                int remote_deleted = !remote;
1687                const struct cache_entry *ce = NULL;
1688
1689                if (index)
1690                        ce = index;
1691                else if (head)
1692                        ce = head;
1693                else if (remote)
1694                        ce = remote;
1695                else {
1696                        for (i = 1; i < o->head_idx; i++) {
1697                                if (stages[i] && stages[i] != o->df_conflict_entry) {
1698                                        ce = stages[i];
1699                                        break;
1700                                }
1701                        }
1702                }
1703
1704                /*
1705                 * Deleted in both.
1706                 * Deleted in one and unchanged in the other.
1707                 */
1708                if ((head_deleted && remote_deleted) ||
1709                    (head_deleted && remote && remote_match) ||
1710                    (remote_deleted && head && head_match)) {
1711                        if (index)
1712                                return deleted_entry(index, index, o);
1713                        if (ce && !head_deleted) {
1714                                if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1715                                        return -1;
1716                        }
1717                        return 0;
1718                }
1719                /*
1720                 * Added in both, identically.
1721                 */
1722                if (no_anc_exists && head && remote && same(head, remote))
1723                        return merged_entry(head, index, o);
1724
1725        }
1726
1727        /* Below are "no merge" cases, which require that the index be
1728         * up-to-date to avoid the files getting overwritten with
1729         * conflict resolution files.
1730         */
1731        if (index) {
1732                if (verify_uptodate(index, o))
1733                        return -1;
1734        }
1735
1736        o->nontrivial_merge = 1;
1737
1738        /* #2, #3, #4, #6, #7, #9, #10, #11. */
1739        count = 0;
1740        if (!head_match || !remote_match) {
1741                for (i = 1; i < o->head_idx; i++) {
1742                        if (stages[i] && stages[i] != o->df_conflict_entry) {
1743                                keep_entry(stages[i], o);
1744                                count++;
1745                                break;
1746                        }
1747                }
1748        }
1749#if DBRT_DEBUG
1750        else {
1751                fprintf(stderr, "read-tree: warning #16 detected\n");
1752                show_stage_entry(stderr, "head   ", stages[head_match]);
1753                show_stage_entry(stderr, "remote ", stages[remote_match]);
1754        }
1755#endif
1756        if (head) { count += keep_entry(head, o); }
1757        if (remote) { count += keep_entry(remote, o); }
1758        return count;
1759}
1760
1761/*
1762 * Two-way merge.
1763 *
1764 * The rule is to "carry forward" what is in the index without losing
1765 * information across a "fast-forward", favoring a successful merge
1766 * over a merge failure when it makes sense.  For details of the
1767 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
1768 *
1769 */
1770int twoway_merge(const struct cache_entry * const *src,
1771                 struct unpack_trees_options *o)
1772{
1773        const struct cache_entry *current = src[0];
1774        const struct cache_entry *oldtree = src[1];
1775        const struct cache_entry *newtree = src[2];
1776
1777        if (o->merge_size != 2)
1778                return error("Cannot do a twoway merge of %d trees",
1779                             o->merge_size);
1780
1781        if (oldtree == o->df_conflict_entry)
1782                oldtree = NULL;
1783        if (newtree == o->df_conflict_entry)
1784                newtree = NULL;
1785
1786        if (current) {
1787                if (current->ce_flags & CE_CONFLICTED) {
1788                        if (same(oldtree, newtree) || o->reset) {
1789                                if (!newtree)
1790                                        return deleted_entry(current, current, o);
1791                                else
1792                                        return merged_entry(newtree, current, o);
1793                        }
1794                        return reject_merge(current, o);
1795                } else if ((!oldtree && !newtree) || /* 4 and 5 */
1796                         (!oldtree && newtree &&
1797                          same(current, newtree)) || /* 6 and 7 */
1798                         (oldtree && newtree &&
1799                          same(oldtree, newtree)) || /* 14 and 15 */
1800                         (oldtree && newtree &&
1801                          !same(oldtree, newtree) && /* 18 and 19 */
1802                          same(current, newtree))) {
1803                        return keep_entry(current, o);
1804                } else if (oldtree && !newtree && same(current, oldtree)) {
1805                        /* 10 or 11 */
1806                        return deleted_entry(oldtree, current, o);
1807                } else if (oldtree && newtree &&
1808                         same(current, oldtree) && !same(current, newtree)) {
1809                        /* 20 or 21 */
1810                        return merged_entry(newtree, current, o);
1811                } else
1812                        return reject_merge(current, o);
1813        }
1814        else if (newtree) {
1815                if (oldtree && !o->initial_checkout) {
1816                        /*
1817                         * deletion of the path was staged;
1818                         */
1819                        if (same(oldtree, newtree))
1820                                return 1;
1821                        return reject_merge(oldtree, o);
1822                }
1823                return merged_entry(newtree, current, o);
1824        }
1825        return deleted_entry(oldtree, current, o);
1826}
1827
1828/*
1829 * Bind merge.
1830 *
1831 * Keep the index entries at stage0, collapse stage1 but make sure
1832 * stage0 does not have anything there.
1833 */
1834int bind_merge(const struct cache_entry * const *src,
1835               struct unpack_trees_options *o)
1836{
1837        const struct cache_entry *old = src[0];
1838        const struct cache_entry *a = src[1];
1839
1840        if (o->merge_size != 1)
1841                return error("Cannot do a bind merge of %d trees",
1842                             o->merge_size);
1843        if (a && old)
1844                return o->gently ? -1 :
1845                        error(ERRORMSG(o, ERROR_BIND_OVERLAP), a->name, old->name);
1846        if (!a)
1847                return keep_entry(old, o);
1848        else
1849                return merged_entry(a, NULL, o);
1850}
1851
1852/*
1853 * One-way merge.
1854 *
1855 * The rule is:
1856 * - take the stat information from stage0, take the data from stage1
1857 */
1858int oneway_merge(const struct cache_entry * const *src,
1859                 struct unpack_trees_options *o)
1860{
1861        const struct cache_entry *old = src[0];
1862        const struct cache_entry *a = src[1];
1863
1864        if (o->merge_size != 1)
1865                return error("Cannot do a oneway merge of %d trees",
1866                             o->merge_size);
1867
1868        if (!a || a == o->df_conflict_entry)
1869                return deleted_entry(old, old, o);
1870
1871        if (old && same(old, a)) {
1872                int update = 0;
1873                if (o->reset && o->update && !ce_uptodate(old) && !ce_skip_worktree(old)) {
1874                        struct stat st;
1875                        if (lstat(old->name, &st) ||
1876                            ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
1877                                update |= CE_UPDATE;
1878                }
1879                add_entry(o, old, update, 0);
1880                return 0;
1881        }
1882        return merged_entry(a, old, o);
1883}