Andrew's git - gitweb.git/blob

b03a250e7cb9072aae525e646184239111f09c3f
   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
  77static void mark_entry_for_delete(size_t pos, void *data)
  78{
  79        struct index_state *istate = data;
  80        if (pos >= istate->cache_nr)
  81                die("position for delete %d exceeds base index size %d",
  82                    (int)pos, istate->cache_nr);
  83        istate->cache[pos]->ce_flags |= CE_REMOVE;
  84        istate->split_index->nr_deletions = 1;
  85}
  86
  87static void replace_entry(size_t pos, void *data)
  88{
  89        struct index_state *istate = data;
  90        struct split_index *si = istate->split_index;
  91        struct cache_entry *dst, *src;
  92        if (pos >= istate->cache_nr)
  93                die("position for replacement %d exceeds base index size %d",
  94                    (int)pos, istate->cache_nr);
  95        if (si->nr_replacements >= si->saved_cache_nr)
  96                die("too many replacements (%d vs %d)",
  97                    si->nr_replacements, si->saved_cache_nr);
  98        dst = istate->cache[pos];
  99        if (dst->ce_flags & CE_REMOVE)
 100                die("entry %d is marked as both replaced and deleted",
 101                    (int)pos);
 102        src = si->saved_cache[si->nr_replacements];
 103        src->index = pos + 1;
 104        src->ce_flags |= CE_UPDATE_IN_BASE;
 105        free(dst);
 106        dst = src;
 107        si->nr_replacements++;
 108}
 109
 110void merge_base_index(struct index_state *istate)
 111{
 112        struct split_index *si = istate->split_index;
 113        unsigned int i;
 114
 115        mark_base_index_entries(si->base);
 116
 117        si->saved_cache     = istate->cache;
 118        si->saved_cache_nr  = istate->cache_nr;
 119        istate->cache_nr    = si->base->cache_nr;
 120        istate->cache       = NULL;
 121        istate->cache_alloc = 0;
 122        ALLOC_GROW(istate->cache, istate->cache_nr, istate->cache_alloc);
 123        memcpy(istate->cache, si->base->cache,
 124               sizeof(*istate->cache) * istate->cache_nr);
 125
 126        si->nr_deletions = 0;
 127        si->nr_replacements = 0;
 128        ewah_each_bit(si->replace_bitmap, replace_entry, istate);
 129        ewah_each_bit(si->delete_bitmap, mark_entry_for_delete, istate);
 130        if (si->nr_deletions)
 131                remove_marked_cache_entries(istate);
 132
 133        for (i = si->nr_replacements; i < si->saved_cache_nr; i++) {
 134                add_index_entry(istate, si->saved_cache[i],
 135                                ADD_CACHE_OK_TO_ADD |
 136                                /*
 137                                 * we may have to replay what
 138                                 * merge-recursive.c:update_stages()
 139                                 * does, which has this flag on
 140                                 */
 141                                ADD_CACHE_SKIP_DFCHECK);
 142                si->saved_cache[i] = NULL;
 143        }
 144
 145        ewah_free(si->delete_bitmap);
 146        ewah_free(si->replace_bitmap);
 147        free(si->saved_cache);
 148        si->delete_bitmap  = NULL;
 149        si->replace_bitmap = NULL;
 150        si->saved_cache    = NULL;
 151        si->saved_cache_nr = 0;
 152}
 153
 154void prepare_to_write_split_index(struct index_state *istate)
 155{
 156        struct split_index *si = init_split_index(istate);
 157        struct cache_entry **entries = NULL, *ce;
 158        int i, nr_entries = 0, nr_alloc = 0;
 159
 160        si->delete_bitmap = ewah_new();
 161        si->replace_bitmap = ewah_new();
 162
 163        if (si->base) {
 164                /* Go through istate->cache[] and mark CE_MATCHED to
 165                 * entry with positive index. We'll go through
 166                 * base->cache[] later to delete all entries in base
 167                 * that are not marked eith either CE_MATCHED or
 168                 * CE_UPDATE_IN_BASE. If istate->cache[i] is a
 169                 * duplicate, deduplicate it.
 170                 */
 171                for (i = 0; i < istate->cache_nr; i++) {
 172                        struct cache_entry *base;
 173                        /* namelen is checked separately */
 174                        const unsigned int ondisk_flags =
 175                                CE_STAGEMASK | CE_VALID | CE_EXTENDED_FLAGS;
 176                        unsigned int ce_flags, base_flags, ret;
 177                        ce = istate->cache[i];
 178                        if (!ce->index)
 179                                continue;
 180                        if (ce->index > si->base->cache_nr) {
 181                                ce->index = 0;
 182                                continue;
 183                        }
 184                        ce->ce_flags |= CE_MATCHED; /* or "shared" */
 185                        base = si->base->cache[ce->index - 1];
 186                        if (ce == base)
 187                                continue;
 188                        if (ce->ce_namelen != base->ce_namelen ||
 189                            strcmp(ce->name, base->name)) {
 190                                ce->index = 0;
 191                                continue;
 192                        }
 193                        ce_flags = ce->ce_flags;
 194                        base_flags = base->ce_flags;
 195                        /* only on-disk flags matter */
 196                        ce->ce_flags   &= ondisk_flags;
 197                        base->ce_flags &= ondisk_flags;
 198                        ret = memcmp(&ce->ce_stat_data, &base->ce_stat_data,
 199                                     offsetof(struct cache_entry, name) -
 200                                     offsetof(struct cache_entry, ce_stat_data));
 201                        ce->ce_flags = ce_flags;
 202                        base->ce_flags = base_flags;
 203                        if (ret)
 204                                ce->ce_flags |= CE_UPDATE_IN_BASE;
 205                        free(base);
 206                        si->base->cache[ce->index - 1] = ce;
 207                }
 208                for (i = 0; i < si->base->cache_nr; i++) {
 209                        ce = si->base->cache[i];
 210                        if ((ce->ce_flags & CE_REMOVE) ||
 211                            !(ce->ce_flags & CE_MATCHED))
 212                                ewah_set(si->delete_bitmap, i);
 213                        else if (ce->ce_flags & CE_UPDATE_IN_BASE) {
 214                                ewah_set(si->replace_bitmap, i);
 215                                ALLOC_GROW(entries, nr_entries+1, nr_alloc);
 216                                entries[nr_entries++] = ce;
 217                        }
 218                }
 219        }
 220
 221        for (i = 0; i < istate->cache_nr; i++) {
 222                ce = istate->cache[i];
 223                if ((!si->base || !ce->index) && !(ce->ce_flags & CE_REMOVE)) {
 224                        ALLOC_GROW(entries, nr_entries+1, nr_alloc);
 225                        entries[nr_entries++] = ce;
 226                }
 227                ce->ce_flags &= ~CE_MATCHED;
 228        }
 229
 230        /*
 231         * take cache[] out temporarily, put entries[] in its place
 232         * for writing
 233         */
 234        si->saved_cache = istate->cache;
 235        si->saved_cache_nr = istate->cache_nr;
 236        istate->cache = entries;
 237        istate->cache_nr = nr_entries;
 238}
 239
 240void finish_writing_split_index(struct index_state *istate)
 241{
 242        struct split_index *si = init_split_index(istate);
 243
 244        ewah_free(si->delete_bitmap);
 245        ewah_free(si->replace_bitmap);
 246        si->delete_bitmap = NULL;
 247        si->replace_bitmap = NULL;
 248        free(istate->cache);
 249        istate->cache = si->saved_cache;
 250        istate->cache_nr = si->saved_cache_nr;
 251}
 252
 253void discard_split_index(struct index_state *istate)
 254{
 255        struct split_index *si = istate->split_index;
 256        if (!si)
 257                return;
 258        istate->split_index = NULL;
 259        si->refcount--;
 260        if (si->refcount)
 261                return;
 262        if (si->base) {
 263                discard_index(si->base);
 264                free(si->base);
 265        }
 266        free(si);
 267}
 268
 269void save_or_free_index_entry(struct index_state *istate, struct cache_entry *ce)
 270{
 271        if (ce->index &&
 272            istate->split_index &&
 273            istate->split_index->base &&
 274            ce->index <= istate->split_index->base->cache_nr &&
 275            ce == istate->split_index->base->cache[ce->index - 1])
 276                ce->ce_flags |= CE_REMOVE;
 277        else
 278                free(ce);
 279}
 280
 281void replace_index_entry_in_base(struct index_state *istate,
 282                                 struct cache_entry *old,
 283                                 struct cache_entry *new)
 284{
 285        if (old->index &&
 286            istate->split_index &&
 287            istate->split_index->base &&
 288            old->index <= istate->split_index->base->cache_nr) {
 289                new->index = old->index;
 290                if (old != istate->split_index->base->cache[new->index - 1])
 291                        free(istate->split_index->base->cache[new->index - 1]);
 292                istate->split_index->base->cache[new->index - 1] = new;
 293        }
 294}