Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "split-index.h"
   3#include "ewah/ewok.h"
   4
   5struct split_index *init_split_index(struct index_state *istate)
   6{
   7        if (!istate->split_index) {
   8                istate->split_index = xcalloc(1, sizeof(*istate->split_index));
   9                istate->split_index->refcount = 1;
  10        }
  11        return istate->split_index;
  12}
  13
  14int read_link_extension(struct index_state *istate,
  15                         const void *data_, unsigned long sz)
  16{
  17        const unsigned char *data = data_;
  18        struct split_index *si;
  19        int ret;
  20
  21        if (sz < 20)
  22                return error("corrupt link extension (too short)");
  23        si = init_split_index(istate);
  24        hashcpy(si->base_sha1, data);
  25        data += 20;
  26        sz -= 20;
  27        if (!sz)
  28                return 0;
  29        si->delete_bitmap = ewah_new();
  30        ret = ewah_read_mmap(si->delete_bitmap, data, sz);
  31        if (ret < 0)
  32                return error("corrupt delete bitmap in link extension");
  33        data += ret;
  34        sz -= ret;
  35        si->replace_bitmap = ewah_new();
  36        ret = ewah_read_mmap(si->replace_bitmap, data, sz);
  37        if (ret < 0)
  38                return error("corrupt replace bitmap in link extension");
  39        if (ret != sz)
  40                return error("garbage at the end of link extension");
  41        return 0;
  42}
  43
  44static int write_strbuf(void *user_data, const void *data, size_t len)
  45{
  46        struct strbuf *sb = user_data;
  47        strbuf_add(sb, data, len);
  48        return len;
  49}
  50
  51int write_link_extension(struct strbuf *sb,
  52                         struct index_state *istate)
  53{
  54        struct split_index *si = istate->split_index;
  55        strbuf_add(sb, si->base_sha1, 20);
  56        if (!si->delete_bitmap && !si->replace_bitmap)
  57                return 0;
  58        ewah_serialize_to(si->delete_bitmap, write_strbuf, sb);
  59        ewah_serialize_to(si->replace_bitmap, write_strbuf, sb);
  60        return 0;
  61}
  62
  63static void mark_base_index_entries(struct index_state *base)
  64{
  65        int i;
  66        /*
  67         * To keep track of the shared entries between
  68         * istate->base->cache[] and istate->cache[], base entry
  69         * position is stored in each base entry. All positions start
  70         * from 1 instead of 0, which is resrved to say "this is a new
  71         * entry".
  72         */
  73        for (i = 0; i < base->cache_nr; i++)
  74                base->cache[i]->index = i + 1;
  75}
  76
  77void move_cache_to_base_index(struct index_state *istate)
  78{
  79        struct split_index *si = istate->split_index;
  80        int i;
  81
  82        /*
  83         * do not delete old si->base, its index entries may be shared
  84         * with istate->cache[]. Accept a bit of leaking here because
  85         * this code is only used by short-lived update-index.
  86         */
  87        si->base = xcalloc(1, sizeof(*si->base));
  88        si->base->version = istate->version;
  89        /* zero timestamp disables racy test in ce_write_index() */
  90        si->base->timestamp = istate->timestamp;
  91        ALLOC_GROW(si->base->cache, istate->cache_nr, si->base->cache_alloc);
  92        si->base->cache_nr = istate->cache_nr;
  93        memcpy(si->base->cache, istate->cache,
  94               sizeof(*istate->cache) * istate->cache_nr);
  95        mark_base_index_entries(si->base);
  96        for (i = 0; i < si->base->cache_nr; i++)
  97                si->base->cache[i]->ce_flags &= ~CE_UPDATE_IN_BASE;
  98}
  99
 100static void mark_entry_for_delete(size_t pos, void *data)
 101{
 102        struct index_state *istate = data;
 103        if (pos >= istate->cache_nr)
 104                die("position for delete %d exceeds base index size %d",
 105                    (int)pos, istate->cache_nr);
 106        istate->cache[pos]->ce_flags |= CE_REMOVE;
 107        istate->split_index->nr_deletions = 1;
 108}
 109
 110static void replace_entry(size_t pos, void *data)
 111{
 112        struct index_state *istate = data;
 113        struct split_index *si = istate->split_index;
 114        struct cache_entry *dst, *src;
 115
 116        if (pos >= istate->cache_nr)
 117                die("position for replacement %d exceeds base index size %d",
 118                    (int)pos, istate->cache_nr);
 119        if (si->nr_replacements >= si->saved_cache_nr)
 120                die("too many replacements (%d vs %d)",
 121                    si->nr_replacements, si->saved_cache_nr);
 122        dst = istate->cache[pos];
 123        if (dst->ce_flags & CE_REMOVE)
 124                die("entry %d is marked as both replaced and deleted",
 125                    (int)pos);
 126        src = si->saved_cache[si->nr_replacements];
 127        if (ce_namelen(src))
 128                die("corrupt link extension, entry %d should have "
 129                    "zero length name", (int)pos);
 130        src->index = pos + 1;
 131        src->ce_flags |= CE_UPDATE_IN_BASE;
 132        src->ce_namelen = dst->ce_namelen;
 133        copy_cache_entry(dst, src);
 134        free(src);
 135        si->nr_replacements++;
 136}
 137
 138void merge_base_index(struct index_state *istate)
 139{
 140        struct split_index *si = istate->split_index;
 141        unsigned int i;
 142
 143        mark_base_index_entries(si->base);
 144
 145        si->saved_cache     = istate->cache;
 146        si->saved_cache_nr  = istate->cache_nr;
 147        istate->cache_nr    = si->base->cache_nr;
 148        istate->cache       = NULL;
 149        istate->cache_alloc = 0;
 150        ALLOC_GROW(istate->cache, istate->cache_nr, istate->cache_alloc);
 151        memcpy(istate->cache, si->base->cache,
 152               sizeof(*istate->cache) * istate->cache_nr);
 153
 154        si->nr_deletions = 0;
 155        si->nr_replacements = 0;
 156        ewah_each_bit(si->replace_bitmap, replace_entry, istate);
 157        ewah_each_bit(si->delete_bitmap, mark_entry_for_delete, istate);
 158        if (si->nr_deletions)
 159                remove_marked_cache_entries(istate);
 160
 161        for (i = si->nr_replacements; i < si->saved_cache_nr; i++) {
 162                if (!ce_namelen(si->saved_cache[i]))
 163                        die("corrupt link extension, entry %d should "
 164                            "have non-zero length name", i);
 165                add_index_entry(istate, si->saved_cache[i],
 166                                ADD_CACHE_OK_TO_ADD |
 167                                ADD_CACHE_KEEP_CACHE_TREE |
 168                                /*
 169                                 * we may have to replay what
 170                                 * merge-recursive.c:update_stages()
 171                                 * does, which has this flag on
 172                                 */
 173                                ADD_CACHE_SKIP_DFCHECK);
 174                si->saved_cache[i] = NULL;
 175        }
 176
 177        ewah_free(si->delete_bitmap);
 178        ewah_free(si->replace_bitmap);
 179        free(si->saved_cache);
 180        si->delete_bitmap  = NULL;
 181        si->replace_bitmap = NULL;
 182        si->saved_cache    = NULL;
 183        si->saved_cache_nr = 0;
 184}
 185
 186void prepare_to_write_split_index(struct index_state *istate)
 187{
 188        struct split_index *si = init_split_index(istate);
 189        struct cache_entry **entries = NULL, *ce;
 190        int i, nr_entries = 0, nr_alloc = 0;
 191
 192        si->delete_bitmap = ewah_new();
 193        si->replace_bitmap = ewah_new();
 194
 195        if (si->base) {
 196                /* Go through istate->cache[] and mark CE_MATCHED to
 197                 * entry with positive index. We'll go through
 198                 * base->cache[] later to delete all entries in base
 199                 * that are not marked eith either CE_MATCHED or
 200                 * CE_UPDATE_IN_BASE. If istate->cache[i] is a
 201                 * duplicate, deduplicate it.
 202                 */
 203                for (i = 0; i < istate->cache_nr; i++) {
 204                        struct cache_entry *base;
 205                        /* namelen is checked separately */
 206                        const unsigned int ondisk_flags =
 207                                CE_STAGEMASK | CE_VALID | CE_EXTENDED_FLAGS;
 208                        unsigned int ce_flags, base_flags, ret;
 209                        ce = istate->cache[i];
 210                        if (!ce->index)
 211                                continue;
 212                        if (ce->index > si->base->cache_nr) {
 213                                ce->index = 0;
 214                                continue;
 215                        }
 216                        ce->ce_flags |= CE_MATCHED; /* or "shared" */
 217                        base = si->base->cache[ce->index - 1];
 218                        if (ce == base)
 219                                continue;
 220                        if (ce->ce_namelen != base->ce_namelen ||
 221                            strcmp(ce->name, base->name)) {
 222                                ce->index = 0;
 223                                continue;
 224                        }
 225                        ce_flags = ce->ce_flags;
 226                        base_flags = base->ce_flags;
 227                        /* only on-disk flags matter */
 228                        ce->ce_flags   &= ondisk_flags;
 229                        base->ce_flags &= ondisk_flags;
 230                        ret = memcmp(&ce->ce_stat_data, &base->ce_stat_data,
 231                                     offsetof(struct cache_entry, name) -
 232                                     offsetof(struct cache_entry, ce_stat_data));
 233                        ce->ce_flags = ce_flags;
 234                        base->ce_flags = base_flags;
 235                        if (ret)
 236                                ce->ce_flags |= CE_UPDATE_IN_BASE;
 237                        free(base);
 238                        si->base->cache[ce->index - 1] = ce;
 239                }
 240                for (i = 0; i < si->base->cache_nr; i++) {
 241                        ce = si->base->cache[i];
 242                        if ((ce->ce_flags & CE_REMOVE) ||
 243                            !(ce->ce_flags & CE_MATCHED))
 244                                ewah_set(si->delete_bitmap, i);
 245                        else if (ce->ce_flags & CE_UPDATE_IN_BASE) {
 246                                ewah_set(si->replace_bitmap, i);
 247                                ce->ce_flags |= CE_STRIP_NAME;
 248                                ALLOC_GROW(entries, nr_entries+1, nr_alloc);
 249                                entries[nr_entries++] = ce;
 250                        }
 251                }
 252        }
 253
 254        for (i = 0; i < istate->cache_nr; i++) {
 255                ce = istate->cache[i];
 256                if ((!si->base || !ce->index) && !(ce->ce_flags & CE_REMOVE)) {
 257                        assert(!(ce->ce_flags & CE_STRIP_NAME));
 258                        ALLOC_GROW(entries, nr_entries+1, nr_alloc);
 259                        entries[nr_entries++] = ce;
 260                }
 261                ce->ce_flags &= ~CE_MATCHED;
 262        }
 263
 264        /*
 265         * take cache[] out temporarily, put entries[] in its place
 266         * for writing
 267         */
 268        si->saved_cache = istate->cache;
 269        si->saved_cache_nr = istate->cache_nr;
 270        istate->cache = entries;
 271        istate->cache_nr = nr_entries;
 272}
 273
 274void finish_writing_split_index(struct index_state *istate)
 275{
 276        struct split_index *si = init_split_index(istate);
 277
 278        ewah_free(si->delete_bitmap);
 279        ewah_free(si->replace_bitmap);
 280        si->delete_bitmap = NULL;
 281        si->replace_bitmap = NULL;
 282        free(istate->cache);
 283        istate->cache = si->saved_cache;
 284        istate->cache_nr = si->saved_cache_nr;
 285}
 286
 287void discard_split_index(struct index_state *istate)
 288{
 289        struct split_index *si = istate->split_index;
 290        if (!si)
 291                return;
 292        istate->split_index = NULL;
 293        si->refcount--;
 294        if (si->refcount)
 295                return;
 296        if (si->base) {
 297                discard_index(si->base);
 298                free(si->base);
 299        }
 300        free(si);
 301}
 302
 303void save_or_free_index_entry(struct index_state *istate, struct cache_entry *ce)
 304{
 305        if (ce->index &&
 306            istate->split_index &&
 307            istate->split_index->base &&
 308            ce->index <= istate->split_index->base->cache_nr &&
 309            ce == istate->split_index->base->cache[ce->index - 1])
 310                ce->ce_flags |= CE_REMOVE;
 311        else
 312                free(ce);
 313}
 314
 315void replace_index_entry_in_base(struct index_state *istate,
 316                                 struct cache_entry *old,
 317                                 struct cache_entry *new)
 318{
 319        if (old->index &&
 320            istate->split_index &&
 321            istate->split_index->base &&
 322            old->index <= istate->split_index->base->cache_nr) {
 323                new->index = old->index;
 324                if (old != istate->split_index->base->cache[new->index - 1])
 325                        free(istate->split_index->base->cache[new->index - 1]);
 326                istate->split_index->base->cache[new->index - 1] = new;
 327        }
 328}