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
  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                                ADD_CACHE_KEEP_CACHE_TREE |
 137                                /*
 138                                 * we may have to replay what
 139                                 * merge-recursive.c:update_stages()
 140                                 * does, which has this flag on
 141                                 */
 142                                ADD_CACHE_SKIP_DFCHECK);
 143                si->saved_cache[i] = NULL;
 144        }
 145
 146        ewah_free(si->delete_bitmap);
 147        ewah_free(si->replace_bitmap);
 148        free(si->saved_cache);
 149        si->delete_bitmap  = NULL;
 150        si->replace_bitmap = NULL;
 151        si->saved_cache    = NULL;
 152        si->saved_cache_nr = 0;
 153}
 154
 155void prepare_to_write_split_index(struct index_state *istate)
 156{
 157        struct split_index *si = init_split_index(istate);
 158        struct cache_entry **entries = NULL, *ce;
 159        int i, nr_entries = 0, nr_alloc = 0;
 160
 161        si->delete_bitmap = ewah_new();
 162        si->replace_bitmap = ewah_new();
 163
 164        if (si->base) {
 165                /* Go through istate->cache[] and mark CE_MATCHED to
 166                 * entry with positive index. We'll go through
 167                 * base->cache[] later to delete all entries in base
 168                 * that are not marked eith either CE_MATCHED or
 169                 * CE_UPDATE_IN_BASE. If istate->cache[i] is a
 170                 * duplicate, deduplicate it.
 171                 */
 172                for (i = 0; i < istate->cache_nr; i++) {
 173                        struct cache_entry *base;
 174                        /* namelen is checked separately */
 175                        const unsigned int ondisk_flags =
 176                                CE_STAGEMASK | CE_VALID | CE_EXTENDED_FLAGS;
 177                        unsigned int ce_flags, base_flags, ret;
 178                        ce = istate->cache[i];
 179                        if (!ce->index)
 180                                continue;
 181                        if (ce->index > si->base->cache_nr) {
 182                                ce->index = 0;
 183                                continue;
 184                        }
 185                        ce->ce_flags |= CE_MATCHED; /* or "shared" */
 186                        base = si->base->cache[ce->index - 1];
 187                        if (ce == base)
 188                                continue;
 189                        if (ce->ce_namelen != base->ce_namelen ||
 190                            strcmp(ce->name, base->name)) {
 191                                ce->index = 0;
 192                                continue;
 193                        }
 194                        ce_flags = ce->ce_flags;
 195                        base_flags = base->ce_flags;
 196                        /* only on-disk flags matter */
 197                        ce->ce_flags   &= ondisk_flags;
 198                        base->ce_flags &= ondisk_flags;
 199                        ret = memcmp(&ce->ce_stat_data, &base->ce_stat_data,
 200                                     offsetof(struct cache_entry, name) -
 201                                     offsetof(struct cache_entry, ce_stat_data));
 202                        ce->ce_flags = ce_flags;
 203                        base->ce_flags = base_flags;
 204                        if (ret)
 205                                ce->ce_flags |= CE_UPDATE_IN_BASE;
 206                        free(base);
 207                        si->base->cache[ce->index - 1] = ce;
 208                }
 209                for (i = 0; i < si->base->cache_nr; i++) {
 210                        ce = si->base->cache[i];
 211                        if ((ce->ce_flags & CE_REMOVE) ||
 212                            !(ce->ce_flags & CE_MATCHED))
 213                                ewah_set(si->delete_bitmap, i);
 214                        else if (ce->ce_flags & CE_UPDATE_IN_BASE) {
 215                                ewah_set(si->replace_bitmap, i);
 216                                ALLOC_GROW(entries, nr_entries+1, nr_alloc);
 217                                entries[nr_entries++] = ce;
 218                        }
 219                }
 220        }
 221
 222        for (i = 0; i < istate->cache_nr; i++) {
 223                ce = istate->cache[i];
 224                if ((!si->base || !ce->index) && !(ce->ce_flags & CE_REMOVE)) {
 225                        ALLOC_GROW(entries, nr_entries+1, nr_alloc);
 226                        entries[nr_entries++] = ce;
 227                }
 228                ce->ce_flags &= ~CE_MATCHED;
 229        }
 230
 231        /*
 232         * take cache[] out temporarily, put entries[] in its place
 233         * for writing
 234         */
 235        si->saved_cache = istate->cache;
 236        si->saved_cache_nr = istate->cache_nr;
 237        istate->cache = entries;
 238        istate->cache_nr = nr_entries;
 239}
 240
 241void finish_writing_split_index(struct index_state *istate)
 242{
 243        struct split_index *si = init_split_index(istate);
 244
 245        ewah_free(si->delete_bitmap);
 246        ewah_free(si->replace_bitmap);
 247        si->delete_bitmap = NULL;
 248        si->replace_bitmap = NULL;
 249        free(istate->cache);
 250        istate->cache = si->saved_cache;
 251        istate->cache_nr = si->saved_cache_nr;
 252}
 253
 254void discard_split_index(struct index_state *istate)
 255{
 256        struct split_index *si = istate->split_index;
 257        if (!si)
 258                return;
 259        istate->split_index = NULL;
 260        si->refcount--;
 261        if (si->refcount)
 262                return;
 263        if (si->base) {
 264                discard_index(si->base);
 265                free(si->base);
 266        }
 267        free(si);
 268}
 269
 270void save_or_free_index_entry(struct index_state *istate, struct cache_entry *ce)
 271{
 272        if (ce->index &&
 273            istate->split_index &&
 274            istate->split_index->base &&
 275            ce->index <= istate->split_index->base->cache_nr &&
 276            ce == istate->split_index->base->cache[ce->index - 1])
 277                ce->ce_flags |= CE_REMOVE;
 278        else
 279                free(ce);
 280}
 281
 282void replace_index_entry_in_base(struct index_state *istate,
 283                                 struct cache_entry *old,
 284                                 struct cache_entry *new)
 285{
 286        if (old->index &&
 287            istate->split_index &&
 288            istate->split_index->base &&
 289            old->index <= istate->split_index->base->cache_nr) {
 290                new->index = old->index;
 291                if (old != istate->split_index->base->cache[new->index - 1])
 292                        free(istate->split_index->base->cache[new->index - 1]);
 293                istate->split_index->base->cache[new->index - 1] = new;
 294        }
 295}