read-cache.con commit describe: Make --tags and --all match lightweight tags more often (7e425c4)
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 */
   6#define NO_THE_INDEX_COMPATIBILITY_MACROS
   7#include "cache.h"
   8#include "cache-tree.h"
   9#include "refs.h"
  10#include "dir.h"
  11#include "tree.h"
  12#include "commit.h"
  13#include "diff.h"
  14#include "diffcore.h"
  15#include "revision.h"
  16#include "blob.h"
  17
  18/* Index extensions.
  19 *
  20 * The first letter should be 'A'..'Z' for extensions that are not
  21 * necessary for a correct operation (i.e. optimization data).
  22 * When new extensions are added that _needs_ to be understood in
  23 * order to correctly interpret the index file, pick character that
  24 * is outside the range, to cause the reader to abort.
  25 */
  26
  27#define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) )
  28#define CACHE_EXT_TREE 0x54524545       /* "TREE" */
  29
  30struct index_state the_index;
  31
  32static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  33{
  34        istate->cache[nr] = ce;
  35        add_name_hash(istate, ce);
  36}
  37
  38static void replace_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  39{
  40        struct cache_entry *old = istate->cache[nr];
  41
  42        remove_name_hash(old);
  43        set_index_entry(istate, nr, ce);
  44        istate->cache_changed = 1;
  45}
  46
  47void rename_index_entry_at(struct index_state *istate, int nr, const char *new_name)
  48{
  49        struct cache_entry *old = istate->cache[nr], *new;
  50        int namelen = strlen(new_name);
  51
  52        new = xmalloc(cache_entry_size(namelen));
  53        copy_cache_entry(new, old);
  54        new->ce_flags &= ~(CE_STATE_MASK | CE_NAMEMASK);
  55        new->ce_flags |= (namelen >= CE_NAMEMASK ? CE_NAMEMASK : namelen);
  56        memcpy(new->name, new_name, namelen + 1);
  57
  58        cache_tree_invalidate_path(istate->cache_tree, old->name);
  59        remove_index_entry_at(istate, nr);
  60        add_index_entry(istate, new, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
  61}
  62
  63/*
  64 * This only updates the "non-critical" parts of the directory
  65 * cache, ie the parts that aren't tracked by GIT, and only used
  66 * to validate the cache.
  67 */
  68void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
  69{
  70        ce->ce_ctime = st->st_ctime;
  71        ce->ce_mtime = st->st_mtime;
  72        ce->ce_dev = st->st_dev;
  73        ce->ce_ino = st->st_ino;
  74        ce->ce_uid = st->st_uid;
  75        ce->ce_gid = st->st_gid;
  76        ce->ce_size = st->st_size;
  77
  78        if (assume_unchanged)
  79                ce->ce_flags |= CE_VALID;
  80
  81        if (S_ISREG(st->st_mode))
  82                ce_mark_uptodate(ce);
  83}
  84
  85static int ce_compare_data(struct cache_entry *ce, struct stat *st)
  86{
  87        int match = -1;
  88        int fd = open(ce->name, O_RDONLY);
  89
  90        if (fd >= 0) {
  91                unsigned char sha1[20];
  92                if (!index_fd(sha1, fd, st, 0, OBJ_BLOB, ce->name))
  93                        match = hashcmp(sha1, ce->sha1);
  94                /* index_fd() closed the file descriptor already */
  95        }
  96        return match;
  97}
  98
  99static int ce_compare_link(struct cache_entry *ce, size_t expected_size)
 100{
 101        int match = -1;
 102        char *target;
 103        void *buffer;
 104        unsigned long size;
 105        enum object_type type;
 106        int len;
 107
 108        target = xmalloc(expected_size);
 109        len = readlink(ce->name, target, expected_size);
 110        if (len != expected_size) {
 111                free(target);
 112                return -1;
 113        }
 114        buffer = read_sha1_file(ce->sha1, &type, &size);
 115        if (!buffer) {
 116                free(target);
 117                return -1;
 118        }
 119        if (size == expected_size)
 120                match = memcmp(buffer, target, size);
 121        free(buffer);
 122        free(target);
 123        return match;
 124}
 125
 126static int ce_compare_gitlink(struct cache_entry *ce)
 127{
 128        unsigned char sha1[20];
 129
 130        /*
 131         * We don't actually require that the .git directory
 132         * under GITLINK directory be a valid git directory. It
 133         * might even be missing (in case nobody populated that
 134         * sub-project).
 135         *
 136         * If so, we consider it always to match.
 137         */
 138        if (resolve_gitlink_ref(ce->name, "HEAD", sha1) < 0)
 139                return 0;
 140        return hashcmp(sha1, ce->sha1);
 141}
 142
 143static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
 144{
 145        switch (st->st_mode & S_IFMT) {
 146        case S_IFREG:
 147                if (ce_compare_data(ce, st))
 148                        return DATA_CHANGED;
 149                break;
 150        case S_IFLNK:
 151                if (ce_compare_link(ce, xsize_t(st->st_size)))
 152                        return DATA_CHANGED;
 153                break;
 154        case S_IFDIR:
 155                if (S_ISGITLINK(ce->ce_mode))
 156                        return ce_compare_gitlink(ce) ? DATA_CHANGED : 0;
 157        default:
 158                return TYPE_CHANGED;
 159        }
 160        return 0;
 161}
 162
 163static int is_empty_blob_sha1(const unsigned char *sha1)
 164{
 165        static const unsigned char empty_blob_sha1[20] = {
 166                0xe6,0x9d,0xe2,0x9b,0xb2,0xd1,0xd6,0x43,0x4b,0x8b,
 167                0x29,0xae,0x77,0x5a,0xd8,0xc2,0xe4,0x8c,0x53,0x91
 168        };
 169
 170        return !hashcmp(sha1, empty_blob_sha1);
 171}
 172
 173static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
 174{
 175        unsigned int changed = 0;
 176
 177        if (ce->ce_flags & CE_REMOVE)
 178                return MODE_CHANGED | DATA_CHANGED | TYPE_CHANGED;
 179
 180        switch (ce->ce_mode & S_IFMT) {
 181        case S_IFREG:
 182                changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
 183                /* We consider only the owner x bit to be relevant for
 184                 * "mode changes"
 185                 */
 186                if (trust_executable_bit &&
 187                    (0100 & (ce->ce_mode ^ st->st_mode)))
 188                        changed |= MODE_CHANGED;
 189                break;
 190        case S_IFLNK:
 191                if (!S_ISLNK(st->st_mode) &&
 192                    (has_symlinks || !S_ISREG(st->st_mode)))
 193                        changed |= TYPE_CHANGED;
 194                break;
 195        case S_IFGITLINK:
 196                /* We ignore most of the st_xxx fields for gitlinks */
 197                if (!S_ISDIR(st->st_mode))
 198                        changed |= TYPE_CHANGED;
 199                else if (ce_compare_gitlink(ce))
 200                        changed |= DATA_CHANGED;
 201                return changed;
 202        default:
 203                die("internal error: ce_mode is %o", ce->ce_mode);
 204        }
 205        if (ce->ce_mtime != (unsigned int) st->st_mtime)
 206                changed |= MTIME_CHANGED;
 207        if (trust_ctime && ce->ce_ctime != (unsigned int) st->st_ctime)
 208                changed |= CTIME_CHANGED;
 209
 210        if (ce->ce_uid != (unsigned int) st->st_uid ||
 211            ce->ce_gid != (unsigned int) st->st_gid)
 212                changed |= OWNER_CHANGED;
 213        if (ce->ce_ino != (unsigned int) st->st_ino)
 214                changed |= INODE_CHANGED;
 215
 216#ifdef USE_STDEV
 217        /*
 218         * st_dev breaks on network filesystems where different
 219         * clients will have different views of what "device"
 220         * the filesystem is on
 221         */
 222        if (ce->ce_dev != (unsigned int) st->st_dev)
 223                changed |= INODE_CHANGED;
 224#endif
 225
 226        if (ce->ce_size != (unsigned int) st->st_size)
 227                changed |= DATA_CHANGED;
 228
 229        /* Racily smudged entry? */
 230        if (!ce->ce_size) {
 231                if (!is_empty_blob_sha1(ce->sha1))
 232                        changed |= DATA_CHANGED;
 233        }
 234
 235        return changed;
 236}
 237
 238static int is_racy_timestamp(const struct index_state *istate, struct cache_entry *ce)
 239{
 240        return (!S_ISGITLINK(ce->ce_mode) &&
 241                istate->timestamp &&
 242                ((unsigned int)istate->timestamp) <= ce->ce_mtime);
 243}
 244
 245int ie_match_stat(const struct index_state *istate,
 246                  struct cache_entry *ce, struct stat *st,
 247                  unsigned int options)
 248{
 249        unsigned int changed;
 250        int ignore_valid = options & CE_MATCH_IGNORE_VALID;
 251        int assume_racy_is_modified = options & CE_MATCH_RACY_IS_DIRTY;
 252
 253        /*
 254         * If it's marked as always valid in the index, it's
 255         * valid whatever the checked-out copy says.
 256         */
 257        if (!ignore_valid && (ce->ce_flags & CE_VALID))
 258                return 0;
 259
 260        changed = ce_match_stat_basic(ce, st);
 261
 262        /*
 263         * Within 1 second of this sequence:
 264         *      echo xyzzy >file && git-update-index --add file
 265         * running this command:
 266         *      echo frotz >file
 267         * would give a falsely clean cache entry.  The mtime and
 268         * length match the cache, and other stat fields do not change.
 269         *
 270         * We could detect this at update-index time (the cache entry
 271         * being registered/updated records the same time as "now")
 272         * and delay the return from git-update-index, but that would
 273         * effectively mean we can make at most one commit per second,
 274         * which is not acceptable.  Instead, we check cache entries
 275         * whose mtime are the same as the index file timestamp more
 276         * carefully than others.
 277         */
 278        if (!changed && is_racy_timestamp(istate, ce)) {
 279                if (assume_racy_is_modified)
 280                        changed |= DATA_CHANGED;
 281                else
 282                        changed |= ce_modified_check_fs(ce, st);
 283        }
 284
 285        return changed;
 286}
 287
 288int ie_modified(const struct index_state *istate,
 289                struct cache_entry *ce, struct stat *st, unsigned int options)
 290{
 291        int changed, changed_fs;
 292
 293        changed = ie_match_stat(istate, ce, st, options);
 294        if (!changed)
 295                return 0;
 296        /*
 297         * If the mode or type has changed, there's no point in trying
 298         * to refresh the entry - it's not going to match
 299         */
 300        if (changed & (MODE_CHANGED | TYPE_CHANGED))
 301                return changed;
 302
 303        /*
 304         * Immediately after read-tree or update-index --cacheinfo,
 305         * the length field is zero, as we have never even read the
 306         * lstat(2) information once, and we cannot trust DATA_CHANGED
 307         * returned by ie_match_stat() which in turn was returned by
 308         * ce_match_stat_basic() to signal that the filesize of the
 309         * blob changed.  We have to actually go to the filesystem to
 310         * see if the contents match, and if so, should answer "unchanged".
 311         *
 312         * The logic does not apply to gitlinks, as ce_match_stat_basic()
 313         * already has checked the actual HEAD from the filesystem in the
 314         * subproject.  If ie_match_stat() already said it is different,
 315         * then we know it is.
 316         */
 317        if ((changed & DATA_CHANGED) &&
 318            (S_ISGITLINK(ce->ce_mode) || ce->ce_size != 0))
 319                return changed;
 320
 321        changed_fs = ce_modified_check_fs(ce, st);
 322        if (changed_fs)
 323                return changed | changed_fs;
 324        return 0;
 325}
 326
 327int base_name_compare(const char *name1, int len1, int mode1,
 328                      const char *name2, int len2, int mode2)
 329{
 330        unsigned char c1, c2;
 331        int len = len1 < len2 ? len1 : len2;
 332        int cmp;
 333
 334        cmp = memcmp(name1, name2, len);
 335        if (cmp)
 336                return cmp;
 337        c1 = name1[len];
 338        c2 = name2[len];
 339        if (!c1 && S_ISDIR(mode1))
 340                c1 = '/';
 341        if (!c2 && S_ISDIR(mode2))
 342                c2 = '/';
 343        return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
 344}
 345
 346/*
 347 * df_name_compare() is identical to base_name_compare(), except it
 348 * compares conflicting directory/file entries as equal. Note that
 349 * while a directory name compares as equal to a regular file, they
 350 * then individually compare _differently_ to a filename that has
 351 * a dot after the basename (because '\0' < '.' < '/').
 352 *
 353 * This is used by routines that want to traverse the git namespace
 354 * but then handle conflicting entries together when possible.
 355 */
 356int df_name_compare(const char *name1, int len1, int mode1,
 357                    const char *name2, int len2, int mode2)
 358{
 359        int len = len1 < len2 ? len1 : len2, cmp;
 360        unsigned char c1, c2;
 361
 362        cmp = memcmp(name1, name2, len);
 363        if (cmp)
 364                return cmp;
 365        /* Directories and files compare equal (same length, same name) */
 366        if (len1 == len2)
 367                return 0;
 368        c1 = name1[len];
 369        if (!c1 && S_ISDIR(mode1))
 370                c1 = '/';
 371        c2 = name2[len];
 372        if (!c2 && S_ISDIR(mode2))
 373                c2 = '/';
 374        if (c1 == '/' && !c2)
 375                return 0;
 376        if (c2 == '/' && !c1)
 377                return 0;
 378        return c1 - c2;
 379}
 380
 381int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
 382{
 383        int len1 = flags1 & CE_NAMEMASK;
 384        int len2 = flags2 & CE_NAMEMASK;
 385        int len = len1 < len2 ? len1 : len2;
 386        int cmp;
 387
 388        cmp = memcmp(name1, name2, len);
 389        if (cmp)
 390                return cmp;
 391        if (len1 < len2)
 392                return -1;
 393        if (len1 > len2)
 394                return 1;
 395
 396        /* Compare stages  */
 397        flags1 &= CE_STAGEMASK;
 398        flags2 &= CE_STAGEMASK;
 399
 400        if (flags1 < flags2)
 401                return -1;
 402        if (flags1 > flags2)
 403                return 1;
 404        return 0;
 405}
 406
 407int index_name_pos(const struct index_state *istate, const char *name, int namelen)
 408{
 409        int first, last;
 410
 411        first = 0;
 412        last = istate->cache_nr;
 413        while (last > first) {
 414                int next = (last + first) >> 1;
 415                struct cache_entry *ce = istate->cache[next];
 416                int cmp = cache_name_compare(name, namelen, ce->name, ce->ce_flags);
 417                if (!cmp)
 418                        return next;
 419                if (cmp < 0) {
 420                        last = next;
 421                        continue;
 422                }
 423                first = next+1;
 424        }
 425        return -first-1;
 426}
 427
 428/* Remove entry, return true if there are more entries to go.. */
 429int remove_index_entry_at(struct index_state *istate, int pos)
 430{
 431        struct cache_entry *ce = istate->cache[pos];
 432
 433        remove_name_hash(ce);
 434        istate->cache_changed = 1;
 435        istate->cache_nr--;
 436        if (pos >= istate->cache_nr)
 437                return 0;
 438        memmove(istate->cache + pos,
 439                istate->cache + pos + 1,
 440                (istate->cache_nr - pos) * sizeof(struct cache_entry *));
 441        return 1;
 442}
 443
 444int remove_file_from_index(struct index_state *istate, const char *path)
 445{
 446        int pos = index_name_pos(istate, path, strlen(path));
 447        if (pos < 0)
 448                pos = -pos-1;
 449        cache_tree_invalidate_path(istate->cache_tree, path);
 450        while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path))
 451                remove_index_entry_at(istate, pos);
 452        return 0;
 453}
 454
 455static int compare_name(struct cache_entry *ce, const char *path, int namelen)
 456{
 457        return namelen != ce_namelen(ce) || memcmp(path, ce->name, namelen);
 458}
 459
 460static int index_name_pos_also_unmerged(struct index_state *istate,
 461        const char *path, int namelen)
 462{
 463        int pos = index_name_pos(istate, path, namelen);
 464        struct cache_entry *ce;
 465
 466        if (pos >= 0)
 467                return pos;
 468
 469        /* maybe unmerged? */
 470        pos = -1 - pos;
 471        if (pos >= istate->cache_nr ||
 472                        compare_name((ce = istate->cache[pos]), path, namelen))
 473                return -1;
 474
 475        /* order of preference: stage 2, 1, 3 */
 476        if (ce_stage(ce) == 1 && pos + 1 < istate->cache_nr &&
 477                        ce_stage((ce = istate->cache[pos + 1])) == 2 &&
 478                        !compare_name(ce, path, namelen))
 479                pos++;
 480        return pos;
 481}
 482
 483static int different_name(struct cache_entry *ce, struct cache_entry *alias)
 484{
 485        int len = ce_namelen(ce);
 486        return ce_namelen(alias) != len || memcmp(ce->name, alias->name, len);
 487}
 488
 489/*
 490 * If we add a filename that aliases in the cache, we will use the
 491 * name that we already have - but we don't want to update the same
 492 * alias twice, because that implies that there were actually two
 493 * different files with aliasing names!
 494 *
 495 * So we use the CE_ADDED flag to verify that the alias was an old
 496 * one before we accept it as
 497 */
 498static struct cache_entry *create_alias_ce(struct cache_entry *ce, struct cache_entry *alias)
 499{
 500        int len;
 501        struct cache_entry *new;
 502
 503        if (alias->ce_flags & CE_ADDED)
 504                die("Will not add file alias '%s' ('%s' already exists in index)", ce->name, alias->name);
 505
 506        /* Ok, create the new entry using the name of the existing alias */
 507        len = ce_namelen(alias);
 508        new = xcalloc(1, cache_entry_size(len));
 509        memcpy(new->name, alias->name, len);
 510        copy_cache_entry(new, ce);
 511        free(ce);
 512        return new;
 513}
 514
 515static void record_intent_to_add(struct cache_entry *ce)
 516{
 517        unsigned char sha1[20];
 518        if (write_sha1_file("", 0, blob_type, sha1))
 519                die("cannot create an empty blob in the object database");
 520        hashcpy(ce->sha1, sha1);
 521}
 522
 523int add_to_index(struct index_state *istate, const char *path, struct stat *st, int flags)
 524{
 525        int size, namelen, was_same;
 526        mode_t st_mode = st->st_mode;
 527        struct cache_entry *ce, *alias;
 528        unsigned ce_option = CE_MATCH_IGNORE_VALID|CE_MATCH_RACY_IS_DIRTY;
 529        int verbose = flags & (ADD_CACHE_VERBOSE | ADD_CACHE_PRETEND);
 530        int pretend = flags & ADD_CACHE_PRETEND;
 531        int intent_only = flags & ADD_CACHE_INTENT;
 532        int add_option = (ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE|
 533                          (intent_only ? ADD_CACHE_NEW_ONLY : 0));
 534
 535        if (!S_ISREG(st_mode) && !S_ISLNK(st_mode) && !S_ISDIR(st_mode))
 536                return error("%s: can only add regular files, symbolic links or git-directories", path);
 537
 538        namelen = strlen(path);
 539        if (S_ISDIR(st_mode)) {
 540                while (namelen && path[namelen-1] == '/')
 541                        namelen--;
 542        }
 543        size = cache_entry_size(namelen);
 544        ce = xcalloc(1, size);
 545        memcpy(ce->name, path, namelen);
 546        ce->ce_flags = namelen;
 547        if (!intent_only)
 548                fill_stat_cache_info(ce, st);
 549
 550        if (trust_executable_bit && has_symlinks)
 551                ce->ce_mode = create_ce_mode(st_mode);
 552        else {
 553                /* If there is an existing entry, pick the mode bits and type
 554                 * from it, otherwise assume unexecutable regular file.
 555                 */
 556                struct cache_entry *ent;
 557                int pos = index_name_pos_also_unmerged(istate, path, namelen);
 558
 559                ent = (0 <= pos) ? istate->cache[pos] : NULL;
 560                ce->ce_mode = ce_mode_from_stat(ent, st_mode);
 561        }
 562
 563        alias = index_name_exists(istate, ce->name, ce_namelen(ce), ignore_case);
 564        if (alias && !ce_stage(alias) && !ie_match_stat(istate, alias, st, ce_option)) {
 565                /* Nothing changed, really */
 566                free(ce);
 567                ce_mark_uptodate(alias);
 568                alias->ce_flags |= CE_ADDED;
 569                return 0;
 570        }
 571        if (!intent_only) {
 572                if (index_path(ce->sha1, path, st, 1))
 573                        return error("unable to index file %s", path);
 574        } else
 575                record_intent_to_add(ce);
 576
 577        if (ignore_case && alias && different_name(ce, alias))
 578                ce = create_alias_ce(ce, alias);
 579        ce->ce_flags |= CE_ADDED;
 580
 581        /* It was suspected to be racily clean, but it turns out to be Ok */
 582        was_same = (alias &&
 583                    !ce_stage(alias) &&
 584                    !hashcmp(alias->sha1, ce->sha1) &&
 585                    ce->ce_mode == alias->ce_mode);
 586
 587        if (pretend)
 588                ;
 589        else if (add_index_entry(istate, ce, add_option))
 590                return error("unable to add %s to index",path);
 591        if (verbose && !was_same)
 592                printf("add '%s'\n", path);
 593        return 0;
 594}
 595
 596int add_file_to_index(struct index_state *istate, const char *path, int flags)
 597{
 598        struct stat st;
 599        if (lstat(path, &st))
 600                die("%s: unable to stat (%s)", path, strerror(errno));
 601        return add_to_index(istate, path, &st, flags);
 602}
 603
 604struct cache_entry *make_cache_entry(unsigned int mode,
 605                const unsigned char *sha1, const char *path, int stage,
 606                int refresh)
 607{
 608        int size, len;
 609        struct cache_entry *ce;
 610
 611        if (!verify_path(path)) {
 612                error("Invalid path '%s'", path);
 613                return NULL;
 614        }
 615
 616        len = strlen(path);
 617        size = cache_entry_size(len);
 618        ce = xcalloc(1, size);
 619
 620        hashcpy(ce->sha1, sha1);
 621        memcpy(ce->name, path, len);
 622        ce->ce_flags = create_ce_flags(len, stage);
 623        ce->ce_mode = create_ce_mode(mode);
 624
 625        if (refresh)
 626                return refresh_cache_entry(ce, 0);
 627
 628        return ce;
 629}
 630
 631int ce_same_name(struct cache_entry *a, struct cache_entry *b)
 632{
 633        int len = ce_namelen(a);
 634        return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
 635}
 636
 637int ce_path_match(const struct cache_entry *ce, const char **pathspec)
 638{
 639        const char *match, *name;
 640        int len;
 641
 642        if (!pathspec)
 643                return 1;
 644
 645        len = ce_namelen(ce);
 646        name = ce->name;
 647        while ((match = *pathspec++) != NULL) {
 648                int matchlen = strlen(match);
 649                if (matchlen > len)
 650                        continue;
 651                if (memcmp(name, match, matchlen))
 652                        continue;
 653                if (matchlen && name[matchlen-1] == '/')
 654                        return 1;
 655                if (name[matchlen] == '/' || !name[matchlen])
 656                        return 1;
 657                if (!matchlen)
 658                        return 1;
 659        }
 660        return 0;
 661}
 662
 663/*
 664 * We fundamentally don't like some paths: we don't want
 665 * dot or dot-dot anywhere, and for obvious reasons don't
 666 * want to recurse into ".git" either.
 667 *
 668 * Also, we don't want double slashes or slashes at the
 669 * end that can make pathnames ambiguous.
 670 */
 671static int verify_dotfile(const char *rest)
 672{
 673        /*
 674         * The first character was '.', but that
 675         * has already been discarded, we now test
 676         * the rest.
 677         */
 678        switch (*rest) {
 679        /* "." is not allowed */
 680        case '\0': case '/':
 681                return 0;
 682
 683        /*
 684         * ".git" followed by  NUL or slash is bad. This
 685         * shares the path end test with the ".." case.
 686         */
 687        case 'g':
 688                if (rest[1] != 'i')
 689                        break;
 690                if (rest[2] != 't')
 691                        break;
 692                rest += 2;
 693        /* fallthrough */
 694        case '.':
 695                if (rest[1] == '\0' || rest[1] == '/')
 696                        return 0;
 697        }
 698        return 1;
 699}
 700
 701int verify_path(const char *path)
 702{
 703        char c;
 704
 705        goto inside;
 706        for (;;) {
 707                if (!c)
 708                        return 1;
 709                if (c == '/') {
 710inside:
 711                        c = *path++;
 712                        switch (c) {
 713                        default:
 714                                continue;
 715                        case '/': case '\0':
 716                                break;
 717                        case '.':
 718                                if (verify_dotfile(path))
 719                                        continue;
 720                        }
 721                        return 0;
 722                }
 723                c = *path++;
 724        }
 725}
 726
 727/*
 728 * Do we have another file that has the beginning components being a
 729 * proper superset of the name we're trying to add?
 730 */
 731static int has_file_name(struct index_state *istate,
 732                         const struct cache_entry *ce, int pos, int ok_to_replace)
 733{
 734        int retval = 0;
 735        int len = ce_namelen(ce);
 736        int stage = ce_stage(ce);
 737        const char *name = ce->name;
 738
 739        while (pos < istate->cache_nr) {
 740                struct cache_entry *p = istate->cache[pos++];
 741
 742                if (len >= ce_namelen(p))
 743                        break;
 744                if (memcmp(name, p->name, len))
 745                        break;
 746                if (ce_stage(p) != stage)
 747                        continue;
 748                if (p->name[len] != '/')
 749                        continue;
 750                if (p->ce_flags & CE_REMOVE)
 751                        continue;
 752                retval = -1;
 753                if (!ok_to_replace)
 754                        break;
 755                remove_index_entry_at(istate, --pos);
 756        }
 757        return retval;
 758}
 759
 760/*
 761 * Do we have another file with a pathname that is a proper
 762 * subset of the name we're trying to add?
 763 */
 764static int has_dir_name(struct index_state *istate,
 765                        const struct cache_entry *ce, int pos, int ok_to_replace)
 766{
 767        int retval = 0;
 768        int stage = ce_stage(ce);
 769        const char *name = ce->name;
 770        const char *slash = name + ce_namelen(ce);
 771
 772        for (;;) {
 773                int len;
 774
 775                for (;;) {
 776                        if (*--slash == '/')
 777                                break;
 778                        if (slash <= ce->name)
 779                                return retval;
 780                }
 781                len = slash - name;
 782
 783                pos = index_name_pos(istate, name, create_ce_flags(len, stage));
 784                if (pos >= 0) {
 785                        /*
 786                         * Found one, but not so fast.  This could
 787                         * be a marker that says "I was here, but
 788                         * I am being removed".  Such an entry is
 789                         * not a part of the resulting tree, and
 790                         * it is Ok to have a directory at the same
 791                         * path.
 792                         */
 793                        if (!(istate->cache[pos]->ce_flags & CE_REMOVE)) {
 794                                retval = -1;
 795                                if (!ok_to_replace)
 796                                        break;
 797                                remove_index_entry_at(istate, pos);
 798                                continue;
 799                        }
 800                }
 801                else
 802                        pos = -pos-1;
 803
 804                /*
 805                 * Trivial optimization: if we find an entry that
 806                 * already matches the sub-directory, then we know
 807                 * we're ok, and we can exit.
 808                 */
 809                while (pos < istate->cache_nr) {
 810                        struct cache_entry *p = istate->cache[pos];
 811                        if ((ce_namelen(p) <= len) ||
 812                            (p->name[len] != '/') ||
 813                            memcmp(p->name, name, len))
 814                                break; /* not our subdirectory */
 815                        if (ce_stage(p) == stage && !(p->ce_flags & CE_REMOVE))
 816                                /*
 817                                 * p is at the same stage as our entry, and
 818                                 * is a subdirectory of what we are looking
 819                                 * at, so we cannot have conflicts at our
 820                                 * level or anything shorter.
 821                                 */
 822                                return retval;
 823                        pos++;
 824                }
 825        }
 826        return retval;
 827}
 828
 829/* We may be in a situation where we already have path/file and path
 830 * is being added, or we already have path and path/file is being
 831 * added.  Either one would result in a nonsense tree that has path
 832 * twice when git-write-tree tries to write it out.  Prevent it.
 833 *
 834 * If ok-to-replace is specified, we remove the conflicting entries
 835 * from the cache so the caller should recompute the insert position.
 836 * When this happens, we return non-zero.
 837 */
 838static int check_file_directory_conflict(struct index_state *istate,
 839                                         const struct cache_entry *ce,
 840                                         int pos, int ok_to_replace)
 841{
 842        int retval;
 843
 844        /*
 845         * When ce is an "I am going away" entry, we allow it to be added
 846         */
 847        if (ce->ce_flags & CE_REMOVE)
 848                return 0;
 849
 850        /*
 851         * We check if the path is a sub-path of a subsequent pathname
 852         * first, since removing those will not change the position
 853         * in the array.
 854         */
 855        retval = has_file_name(istate, ce, pos, ok_to_replace);
 856
 857        /*
 858         * Then check if the path might have a clashing sub-directory
 859         * before it.
 860         */
 861        return retval + has_dir_name(istate, ce, pos, ok_to_replace);
 862}
 863
 864static int add_index_entry_with_check(struct index_state *istate, struct cache_entry *ce, int option)
 865{
 866        int pos;
 867        int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
 868        int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
 869        int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
 870        int new_only = option & ADD_CACHE_NEW_ONLY;
 871
 872        cache_tree_invalidate_path(istate->cache_tree, ce->name);
 873        pos = index_name_pos(istate, ce->name, ce->ce_flags);
 874
 875        /* existing match? Just replace it. */
 876        if (pos >= 0) {
 877                if (!new_only)
 878                        replace_index_entry(istate, pos, ce);
 879                return 0;
 880        }
 881        pos = -pos-1;
 882
 883        /*
 884         * Inserting a merged entry ("stage 0") into the index
 885         * will always replace all non-merged entries..
 886         */
 887        if (pos < istate->cache_nr && ce_stage(ce) == 0) {
 888                while (ce_same_name(istate->cache[pos], ce)) {
 889                        ok_to_add = 1;
 890                        if (!remove_index_entry_at(istate, pos))
 891                                break;
 892                }
 893        }
 894
 895        if (!ok_to_add)
 896                return -1;
 897        if (!verify_path(ce->name))
 898                return error("Invalid path '%s'", ce->name);
 899
 900        if (!skip_df_check &&
 901            check_file_directory_conflict(istate, ce, pos, ok_to_replace)) {
 902                if (!ok_to_replace)
 903                        return error("'%s' appears as both a file and as a directory",
 904                                     ce->name);
 905                pos = index_name_pos(istate, ce->name, ce->ce_flags);
 906                pos = -pos-1;
 907        }
 908        return pos + 1;
 909}
 910
 911int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option)
 912{
 913        int pos;
 914
 915        if (option & ADD_CACHE_JUST_APPEND)
 916                pos = istate->cache_nr;
 917        else {
 918                int ret;
 919                ret = add_index_entry_with_check(istate, ce, option);
 920                if (ret <= 0)
 921                        return ret;
 922                pos = ret - 1;
 923        }
 924
 925        /* Make sure the array is big enough .. */
 926        if (istate->cache_nr == istate->cache_alloc) {
 927                istate->cache_alloc = alloc_nr(istate->cache_alloc);
 928                istate->cache = xrealloc(istate->cache,
 929                                        istate->cache_alloc * sizeof(struct cache_entry *));
 930        }
 931
 932        /* Add it in.. */
 933        istate->cache_nr++;
 934        if (istate->cache_nr > pos + 1)
 935                memmove(istate->cache + pos + 1,
 936                        istate->cache + pos,
 937                        (istate->cache_nr - pos - 1) * sizeof(ce));
 938        set_index_entry(istate, pos, ce);
 939        istate->cache_changed = 1;
 940        return 0;
 941}
 942
 943/*
 944 * "refresh" does not calculate a new sha1 file or bring the
 945 * cache up-to-date for mode/content changes. But what it
 946 * _does_ do is to "re-match" the stat information of a file
 947 * with the cache, so that you can refresh the cache for a
 948 * file that hasn't been changed but where the stat entry is
 949 * out of date.
 950 *
 951 * For example, you'd want to do this after doing a "git-read-tree",
 952 * to link up the stat cache details with the proper files.
 953 */
 954static struct cache_entry *refresh_cache_ent(struct index_state *istate,
 955                                             struct cache_entry *ce,
 956                                             unsigned int options, int *err)
 957{
 958        struct stat st;
 959        struct cache_entry *updated;
 960        int changed, size;
 961        int ignore_valid = options & CE_MATCH_IGNORE_VALID;
 962
 963        if (ce_uptodate(ce))
 964                return ce;
 965
 966        /*
 967         * CE_VALID means the user promised us that the change to
 968         * the work tree does not matter and told us not to worry.
 969         */
 970        if (!ignore_valid && (ce->ce_flags & CE_VALID)) {
 971                ce_mark_uptodate(ce);
 972                return ce;
 973        }
 974
 975        if (lstat(ce->name, &st) < 0) {
 976                if (err)
 977                        *err = errno;
 978                return NULL;
 979        }
 980
 981        changed = ie_match_stat(istate, ce, &st, options);
 982        if (!changed) {
 983                /*
 984                 * The path is unchanged.  If we were told to ignore
 985                 * valid bit, then we did the actual stat check and
 986                 * found that the entry is unmodified.  If the entry
 987                 * is not marked VALID, this is the place to mark it
 988                 * valid again, under "assume unchanged" mode.
 989                 */
 990                if (ignore_valid && assume_unchanged &&
 991                    !(ce->ce_flags & CE_VALID))
 992                        ; /* mark this one VALID again */
 993                else {
 994                        /*
 995                         * We do not mark the index itself "modified"
 996                         * because CE_UPTODATE flag is in-core only;
 997                         * we are not going to write this change out.
 998                         */
 999                        ce_mark_uptodate(ce);
1000                        return ce;
1001                }
1002        }
1003
1004        if (ie_modified(istate, ce, &st, options)) {
1005                if (err)
1006                        *err = EINVAL;
1007                return NULL;
1008        }
1009
1010        size = ce_size(ce);
1011        updated = xmalloc(size);
1012        memcpy(updated, ce, size);
1013        fill_stat_cache_info(updated, &st);
1014        /*
1015         * If ignore_valid is not set, we should leave CE_VALID bit
1016         * alone.  Otherwise, paths marked with --no-assume-unchanged
1017         * (i.e. things to be edited) will reacquire CE_VALID bit
1018         * automatically, which is not really what we want.
1019         */
1020        if (!ignore_valid && assume_unchanged &&
1021            !(ce->ce_flags & CE_VALID))
1022                updated->ce_flags &= ~CE_VALID;
1023
1024        return updated;
1025}
1026
1027int refresh_index(struct index_state *istate, unsigned int flags, const char **pathspec, char *seen)
1028{
1029        int i;
1030        int has_errors = 0;
1031        int really = (flags & REFRESH_REALLY) != 0;
1032        int allow_unmerged = (flags & REFRESH_UNMERGED) != 0;
1033        int quiet = (flags & REFRESH_QUIET) != 0;
1034        int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
1035        int ignore_submodules = (flags & REFRESH_IGNORE_SUBMODULES) != 0;
1036        unsigned int options = really ? CE_MATCH_IGNORE_VALID : 0;
1037        const char *needs_update_message;
1038
1039        needs_update_message = ((flags & REFRESH_SAY_CHANGED)
1040                                ? "locally modified" : "needs update");
1041        for (i = 0; i < istate->cache_nr; i++) {
1042                struct cache_entry *ce, *new;
1043                int cache_errno = 0;
1044
1045                ce = istate->cache[i];
1046                if (ignore_submodules && S_ISGITLINK(ce->ce_mode))
1047                        continue;
1048
1049                if (ce_stage(ce)) {
1050                        while ((i < istate->cache_nr) &&
1051                               ! strcmp(istate->cache[i]->name, ce->name))
1052                                i++;
1053                        i--;
1054                        if (allow_unmerged)
1055                                continue;
1056                        printf("%s: needs merge\n", ce->name);
1057                        has_errors = 1;
1058                        continue;
1059                }
1060
1061                if (pathspec && !match_pathspec(pathspec, ce->name, strlen(ce->name), 0, seen))
1062                        continue;
1063
1064                new = refresh_cache_ent(istate, ce, options, &cache_errno);
1065                if (new == ce)
1066                        continue;
1067                if (!new) {
1068                        if (not_new && cache_errno == ENOENT)
1069                                continue;
1070                        if (really && cache_errno == EINVAL) {
1071                                /* If we are doing --really-refresh that
1072                                 * means the index is not valid anymore.
1073                                 */
1074                                ce->ce_flags &= ~CE_VALID;
1075                                istate->cache_changed = 1;
1076                        }
1077                        if (quiet)
1078                                continue;
1079                        printf("%s: %s\n", ce->name, needs_update_message);
1080                        has_errors = 1;
1081                        continue;
1082                }
1083
1084                replace_index_entry(istate, i, new);
1085        }
1086        return has_errors;
1087}
1088
1089struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
1090{
1091        return refresh_cache_ent(&the_index, ce, really, NULL);
1092}
1093
1094static int verify_hdr(struct cache_header *hdr, unsigned long size)
1095{
1096        git_SHA_CTX c;
1097        unsigned char sha1[20];
1098
1099        if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
1100                return error("bad signature");
1101        if (hdr->hdr_version != htonl(2))
1102                return error("bad index version");
1103        git_SHA1_Init(&c);
1104        git_SHA1_Update(&c, hdr, size - 20);
1105        git_SHA1_Final(sha1, &c);
1106        if (hashcmp(sha1, (unsigned char *)hdr + size - 20))
1107                return error("bad index file sha1 signature");
1108        return 0;
1109}
1110
1111static int read_index_extension(struct index_state *istate,
1112                                const char *ext, void *data, unsigned long sz)
1113{
1114        switch (CACHE_EXT(ext)) {
1115        case CACHE_EXT_TREE:
1116                istate->cache_tree = cache_tree_read(data, sz);
1117                break;
1118        default:
1119                if (*ext < 'A' || 'Z' < *ext)
1120                        return error("index uses %.4s extension, which we do not understand",
1121                                     ext);
1122                fprintf(stderr, "ignoring %.4s extension\n", ext);
1123                break;
1124        }
1125        return 0;
1126}
1127
1128int read_index(struct index_state *istate)
1129{
1130        return read_index_from(istate, get_index_file());
1131}
1132
1133static void convert_from_disk(struct ondisk_cache_entry *ondisk, struct cache_entry *ce)
1134{
1135        size_t len;
1136
1137        ce->ce_ctime = ntohl(ondisk->ctime.sec);
1138        ce->ce_mtime = ntohl(ondisk->mtime.sec);
1139        ce->ce_dev   = ntohl(ondisk->dev);
1140        ce->ce_ino   = ntohl(ondisk->ino);
1141        ce->ce_mode  = ntohl(ondisk->mode);
1142        ce->ce_uid   = ntohl(ondisk->uid);
1143        ce->ce_gid   = ntohl(ondisk->gid);
1144        ce->ce_size  = ntohl(ondisk->size);
1145        /* On-disk flags are just 16 bits */
1146        ce->ce_flags = ntohs(ondisk->flags);
1147
1148        /* For future extension: we do not understand this entry yet */
1149        if (ce->ce_flags & CE_EXTENDED)
1150                die("Unknown index entry format");
1151        hashcpy(ce->sha1, ondisk->sha1);
1152
1153        len = ce->ce_flags & CE_NAMEMASK;
1154        if (len == CE_NAMEMASK)
1155                len = strlen(ondisk->name);
1156        /*
1157         * NEEDSWORK: If the original index is crafted, this copy could
1158         * go unchecked.
1159         */
1160        memcpy(ce->name, ondisk->name, len + 1);
1161}
1162
1163static inline size_t estimate_cache_size(size_t ondisk_size, unsigned int entries)
1164{
1165        long per_entry;
1166
1167        per_entry = sizeof(struct cache_entry) - sizeof(struct ondisk_cache_entry);
1168
1169        /*
1170         * Alignment can cause differences. This should be "alignof", but
1171         * since that's a gcc'ism, just use the size of a pointer.
1172         */
1173        per_entry += sizeof(void *);
1174        return ondisk_size + entries*per_entry;
1175}
1176
1177/* remember to discard_cache() before reading a different cache! */
1178int read_index_from(struct index_state *istate, const char *path)
1179{
1180        int fd, i;
1181        struct stat st;
1182        unsigned long src_offset, dst_offset;
1183        struct cache_header *hdr;
1184        void *mmap;
1185        size_t mmap_size;
1186
1187        errno = EBUSY;
1188        if (istate->initialized)
1189                return istate->cache_nr;
1190
1191        errno = ENOENT;
1192        istate->timestamp = 0;
1193        fd = open(path, O_RDONLY);
1194        if (fd < 0) {
1195                if (errno == ENOENT)
1196                        return 0;
1197                die("index file open failed (%s)", strerror(errno));
1198        }
1199
1200        if (fstat(fd, &st))
1201                die("cannot stat the open index (%s)", strerror(errno));
1202
1203        errno = EINVAL;
1204        mmap_size = xsize_t(st.st_size);
1205        if (mmap_size < sizeof(struct cache_header) + 20)
1206                die("index file smaller than expected");
1207
1208        mmap = xmmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
1209        close(fd);
1210        if (mmap == MAP_FAILED)
1211                die("unable to map index file");
1212
1213        hdr = mmap;
1214        if (verify_hdr(hdr, mmap_size) < 0)
1215                goto unmap;
1216
1217        istate->cache_nr = ntohl(hdr->hdr_entries);
1218        istate->cache_alloc = alloc_nr(istate->cache_nr);
1219        istate->cache = xcalloc(istate->cache_alloc, sizeof(struct cache_entry *));
1220
1221        /*
1222         * The disk format is actually larger than the in-memory format,
1223         * due to space for nsec etc, so even though the in-memory one
1224         * has room for a few  more flags, we can allocate using the same
1225         * index size
1226         */
1227        istate->alloc = xmalloc(estimate_cache_size(mmap_size, istate->cache_nr));
1228        istate->initialized = 1;
1229
1230        src_offset = sizeof(*hdr);
1231        dst_offset = 0;
1232        for (i = 0; i < istate->cache_nr; i++) {
1233                struct ondisk_cache_entry *disk_ce;
1234                struct cache_entry *ce;
1235
1236                disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset);
1237                ce = (struct cache_entry *)((char *)istate->alloc + dst_offset);
1238                convert_from_disk(disk_ce, ce);
1239                set_index_entry(istate, i, ce);
1240
1241                src_offset += ondisk_ce_size(ce);
1242                dst_offset += ce_size(ce);
1243        }
1244        istate->timestamp = st.st_mtime;
1245        while (src_offset <= mmap_size - 20 - 8) {
1246                /* After an array of active_nr index entries,
1247                 * there can be arbitrary number of extended
1248                 * sections, each of which is prefixed with
1249                 * extension name (4-byte) and section length
1250                 * in 4-byte network byte order.
1251                 */
1252                unsigned long extsize;
1253                memcpy(&extsize, (char *)mmap + src_offset + 4, 4);
1254                extsize = ntohl(extsize);
1255                if (read_index_extension(istate,
1256                                         (const char *) mmap + src_offset,
1257                                         (char *) mmap + src_offset + 8,
1258                                         extsize) < 0)
1259                        goto unmap;
1260                src_offset += 8;
1261                src_offset += extsize;
1262        }
1263        munmap(mmap, mmap_size);
1264        return istate->cache_nr;
1265
1266unmap:
1267        munmap(mmap, mmap_size);
1268        errno = EINVAL;
1269        die("index file corrupt");
1270}
1271
1272int discard_index(struct index_state *istate)
1273{
1274        istate->cache_nr = 0;
1275        istate->cache_changed = 0;
1276        istate->timestamp = 0;
1277        istate->name_hash_initialized = 0;
1278        free_hash(&istate->name_hash);
1279        cache_tree_free(&(istate->cache_tree));
1280        free(istate->alloc);
1281        istate->alloc = NULL;
1282        istate->initialized = 0;
1283
1284        /* no need to throw away allocated active_cache */
1285        return 0;
1286}
1287
1288int unmerged_index(const struct index_state *istate)
1289{
1290        int i;
1291        for (i = 0; i < istate->cache_nr; i++) {
1292                if (ce_stage(istate->cache[i]))
1293                        return 1;
1294        }
1295        return 0;
1296}
1297
1298#define WRITE_BUFFER_SIZE 8192
1299static unsigned char write_buffer[WRITE_BUFFER_SIZE];
1300static unsigned long write_buffer_len;
1301
1302static int ce_write_flush(git_SHA_CTX *context, int fd)
1303{
1304        unsigned int buffered = write_buffer_len;
1305        if (buffered) {
1306                git_SHA1_Update(context, write_buffer, buffered);
1307                if (write_in_full(fd, write_buffer, buffered) != buffered)
1308                        return -1;
1309                write_buffer_len = 0;
1310        }
1311        return 0;
1312}
1313
1314static int ce_write(git_SHA_CTX *context, int fd, void *data, unsigned int len)
1315{
1316        while (len) {
1317                unsigned int buffered = write_buffer_len;
1318                unsigned int partial = WRITE_BUFFER_SIZE - buffered;
1319                if (partial > len)
1320                        partial = len;
1321                memcpy(write_buffer + buffered, data, partial);
1322                buffered += partial;
1323                if (buffered == WRITE_BUFFER_SIZE) {
1324                        write_buffer_len = buffered;
1325                        if (ce_write_flush(context, fd))
1326                                return -1;
1327                        buffered = 0;
1328                }
1329                write_buffer_len = buffered;
1330                len -= partial;
1331                data = (char *) data + partial;
1332        }
1333        return 0;
1334}
1335
1336static int write_index_ext_header(git_SHA_CTX *context, int fd,
1337                                  unsigned int ext, unsigned int sz)
1338{
1339        ext = htonl(ext);
1340        sz = htonl(sz);
1341        return ((ce_write(context, fd, &ext, 4) < 0) ||
1342                (ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
1343}
1344
1345static int ce_flush(git_SHA_CTX *context, int fd)
1346{
1347        unsigned int left = write_buffer_len;
1348
1349        if (left) {
1350                write_buffer_len = 0;
1351                git_SHA1_Update(context, write_buffer, left);
1352        }
1353
1354        /* Flush first if not enough space for SHA1 signature */
1355        if (left + 20 > WRITE_BUFFER_SIZE) {
1356                if (write_in_full(fd, write_buffer, left) != left)
1357                        return -1;
1358                left = 0;
1359        }
1360
1361        /* Append the SHA1 signature at the end */
1362        git_SHA1_Final(write_buffer + left, context);
1363        left += 20;
1364        return (write_in_full(fd, write_buffer, left) != left) ? -1 : 0;
1365}
1366
1367static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
1368{
1369        /*
1370         * The only thing we care about in this function is to smudge the
1371         * falsely clean entry due to touch-update-touch race, so we leave
1372         * everything else as they are.  We are called for entries whose
1373         * ce_mtime match the index file mtime.
1374         *
1375         * Note that this actually does not do much for gitlinks, for
1376         * which ce_match_stat_basic() always goes to the actual
1377         * contents.  The caller checks with is_racy_timestamp() which
1378         * always says "no" for gitlinks, so we are not called for them ;-)
1379         */
1380        struct stat st;
1381
1382        if (lstat(ce->name, &st) < 0)
1383                return;
1384        if (ce_match_stat_basic(ce, &st))
1385                return;
1386        if (ce_modified_check_fs(ce, &st)) {
1387                /* This is "racily clean"; smudge it.  Note that this
1388                 * is a tricky code.  At first glance, it may appear
1389                 * that it can break with this sequence:
1390                 *
1391                 * $ echo xyzzy >frotz
1392                 * $ git-update-index --add frotz
1393                 * $ : >frotz
1394                 * $ sleep 3
1395                 * $ echo filfre >nitfol
1396                 * $ git-update-index --add nitfol
1397                 *
1398                 * but it does not.  When the second update-index runs,
1399                 * it notices that the entry "frotz" has the same timestamp
1400                 * as index, and if we were to smudge it by resetting its
1401                 * size to zero here, then the object name recorded
1402                 * in index is the 6-byte file but the cached stat information
1403                 * becomes zero --- which would then match what we would
1404                 * obtain from the filesystem next time we stat("frotz").
1405                 *
1406                 * However, the second update-index, before calling
1407                 * this function, notices that the cached size is 6
1408                 * bytes and what is on the filesystem is an empty
1409                 * file, and never calls us, so the cached size information
1410                 * for "frotz" stays 6 which does not match the filesystem.
1411                 */
1412                ce->ce_size = 0;
1413        }
1414}
1415
1416static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce)
1417{
1418        int size = ondisk_ce_size(ce);
1419        struct ondisk_cache_entry *ondisk = xcalloc(1, size);
1420
1421        ondisk->ctime.sec = htonl(ce->ce_ctime);
1422        ondisk->ctime.nsec = 0;
1423        ondisk->mtime.sec = htonl(ce->ce_mtime);
1424        ondisk->mtime.nsec = 0;
1425        ondisk->dev  = htonl(ce->ce_dev);
1426        ondisk->ino  = htonl(ce->ce_ino);
1427        ondisk->mode = htonl(ce->ce_mode);
1428        ondisk->uid  = htonl(ce->ce_uid);
1429        ondisk->gid  = htonl(ce->ce_gid);
1430        ondisk->size = htonl(ce->ce_size);
1431        hashcpy(ondisk->sha1, ce->sha1);
1432        ondisk->flags = htons(ce->ce_flags);
1433        memcpy(ondisk->name, ce->name, ce_namelen(ce));
1434
1435        return ce_write(c, fd, ondisk, size);
1436}
1437
1438int write_index(const struct index_state *istate, int newfd)
1439{
1440        git_SHA_CTX c;
1441        struct cache_header hdr;
1442        int i, err, removed;
1443        struct cache_entry **cache = istate->cache;
1444        int entries = istate->cache_nr;
1445
1446        for (i = removed = 0; i < entries; i++)
1447                if (cache[i]->ce_flags & CE_REMOVE)
1448                        removed++;
1449
1450        hdr.hdr_signature = htonl(CACHE_SIGNATURE);
1451        hdr.hdr_version = htonl(2);
1452        hdr.hdr_entries = htonl(entries - removed);
1453
1454        git_SHA1_Init(&c);
1455        if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
1456                return -1;
1457
1458        for (i = 0; i < entries; i++) {
1459                struct cache_entry *ce = cache[i];
1460                if (ce->ce_flags & CE_REMOVE)
1461                        continue;
1462                if (!ce_uptodate(ce) && is_racy_timestamp(istate, ce))
1463                        ce_smudge_racily_clean_entry(ce);
1464                if (ce_write_entry(&c, newfd, ce) < 0)
1465                        return -1;
1466        }
1467
1468        /* Write extension data here */
1469        if (istate->cache_tree) {
1470                struct strbuf sb = STRBUF_INIT;
1471
1472                cache_tree_write(&sb, istate->cache_tree);
1473                err = write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sb.len) < 0
1474                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
1475                strbuf_release(&sb);
1476                if (err)
1477                        return -1;
1478        }
1479        return ce_flush(&c, newfd);
1480}
1481
1482/*
1483 * Read the index file that is potentially unmerged into given
1484 * index_state, dropping any unmerged entries.  Returns true is
1485 * the index is unmerged.  Callers who want to refuse to work
1486 * from an unmerged state can call this and check its return value,
1487 * instead of calling read_cache().
1488 */
1489int read_index_unmerged(struct index_state *istate)
1490{
1491        int i;
1492        struct cache_entry **dst;
1493        struct cache_entry *last = NULL;
1494
1495        read_index(istate);
1496        dst = istate->cache;
1497        for (i = 0; i < istate->cache_nr; i++) {
1498                struct cache_entry *ce = istate->cache[i];
1499                if (ce_stage(ce)) {
1500                        remove_name_hash(ce);
1501                        if (last && !strcmp(ce->name, last->name))
1502                                continue;
1503                        cache_tree_invalidate_path(istate->cache_tree, ce->name);
1504                        last = ce;
1505                        continue;
1506                }
1507                *dst++ = ce;
1508        }
1509        istate->cache_nr = dst - istate->cache;
1510        return !!last;
1511}
1512
1513struct update_callback_data
1514{
1515        int flags;
1516        int add_errors;
1517};
1518
1519static void update_callback(struct diff_queue_struct *q,
1520                            struct diff_options *opt, void *cbdata)
1521{
1522        int i;
1523        struct update_callback_data *data = cbdata;
1524
1525        for (i = 0; i < q->nr; i++) {
1526                struct diff_filepair *p = q->queue[i];
1527                const char *path = p->one->path;
1528                switch (p->status) {
1529                default:
1530                        die("unexpected diff status %c", p->status);
1531                case DIFF_STATUS_UNMERGED:
1532                case DIFF_STATUS_MODIFIED:
1533                case DIFF_STATUS_TYPE_CHANGED:
1534                        if (add_file_to_index(&the_index, path, data->flags)) {
1535                                if (!(data->flags & ADD_CACHE_IGNORE_ERRORS))
1536                                        die("updating files failed");
1537                                data->add_errors++;
1538                        }
1539                        break;
1540                case DIFF_STATUS_DELETED:
1541                        if (data->flags & ADD_CACHE_IGNORE_REMOVAL)
1542                                break;
1543                        if (!(data->flags & ADD_CACHE_PRETEND))
1544                                remove_file_from_index(&the_index, path);
1545                        if (data->flags & (ADD_CACHE_PRETEND|ADD_CACHE_VERBOSE))
1546                                printf("remove '%s'\n", path);
1547                        break;
1548                }
1549        }
1550}
1551
1552int add_files_to_cache(const char *prefix, const char **pathspec, int flags)
1553{
1554        struct update_callback_data data;
1555        struct rev_info rev;
1556        init_revisions(&rev, prefix);
1557        setup_revisions(0, NULL, &rev, NULL);
1558        rev.prune_data = pathspec;
1559        rev.diffopt.output_format = DIFF_FORMAT_CALLBACK;
1560        rev.diffopt.format_callback = update_callback;
1561        data.flags = flags;
1562        data.add_errors = 0;
1563        rev.diffopt.format_callback_data = &data;
1564        run_diff_files(&rev, DIFF_RACY_IS_MODIFIED);
1565        return !!data.add_errors;
1566}
1567