Andrew's git - gitweb.git/blob

ee3246f391a6ea7524e1bc40b535f33fa662bd3c
   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
  93        if (pos >= istate->cache_nr)
  94                die("position for replacement %d exceeds base index size %d",
  95                    (int)pos, istate->cache_nr);
  96        if (si->nr_replacements >= si->saved_cache_nr)
  97                die("too many replacements (%d vs %d)",
  98                    si->nr_replacements, si->saved_cache_nr);
  99        dst = istate->cache[pos];
 100        if (dst->ce_flags & CE_REMOVE)
 101                die("entry %d is marked as both replaced and deleted",
 102                    (int)pos);
 103        src = si->saved_cache[si->nr_replacements];
 104        if (ce_namelen(src))
 105                die("corrupt link extension, entry %d should have "
 106                    "zero length name", (int)pos);
 107        src->index = pos + 1;
 108        src->ce_flags |= CE_UPDATE_IN_BASE;
 109        src->ce_namelen = dst->ce_namelen;
 110        copy_cache_entry(dst, src);
 111        free(src);
 112        si->nr_replacements++;
 113}
 114
 115void merge_base_index(struct index_state *istate)
 116{
 117        struct split_index *si = istate->split_index;
 118        unsigned int i;
 119
 120        mark_base_index_entries(si->base);
 121
 122        si->saved_cache     = istate->cache;
 123        si->saved_cache_nr  = istate->cache_nr;
 124        istate->cache_nr    = si->base->cache_nr;
 125        istate->cache       = NULL;
 126        istate->cache_alloc = 0;
 127        ALLOC_GROW(istate->cache, istate->cache_nr, istate->cache_alloc);
 128        memcpy(istate->cache, si->base->cache,
 129               sizeof(*istate->cache) * istate->cache_nr);
 130
 131        si->nr_deletions = 0;
 132        si->nr_replacements = 0;
 133        ewah_each_bit(si->replace_bitmap, replace_entry, istate);
 134        ewah_each_bit(si->delete_bitmap, mark_entry_for_delete, istate);
 135        if (si->nr_deletions)
 136                remove_marked_cache_entries(istate);
 137
 138        for (i = si->nr_replacements; i < si->saved_cache_nr; i++) {
 139                if (!ce_namelen(si->saved_cache[i]))
 140                        die("corrupt link extension, entry %d should "
 141                            "have non-zero length name", i);
 142                add_index_entry(istate, si->saved_cache[i],
 143                                ADD_CACHE_OK_TO_ADD |
 144                                ADD_CACHE_KEEP_CACHE_TREE |
 145                                /*
 146                                 * we may have to replay what
 147                                 * merge-recursive.c:update_stages()
 148                                 * does, which has this flag on
 149                                 */
 150                                ADD_CACHE_SKIP_DFCHECK);
 151                si->saved_cache[i] = NULL;
 152        }
 153
 154        ewah_free(si->delete_bitmap);
 155        ewah_free(si->replace_bitmap);
 156        free(si->saved_cache);
 157        si->delete_bitmap  = NULL;
 158        si->replace_bitmap = NULL;
 159        si->saved_cache    = NULL;
 160        si->saved_cache_nr = 0;
 161}
 162
 163void prepare_to_write_split_index(struct index_state *istate)
 164{
 165        struct split_index *si = init_split_index(istate);
 166        struct cache_entry **entries = NULL, *ce;
 167        int i, nr_entries = 0, nr_alloc = 0;
 168
 169        si->delete_bitmap = ewah_new();
 170        si->replace_bitmap = ewah_new();
 171
 172        if (si->base) {
 173                /* Go through istate->cache[] and mark CE_MATCHED to
 174                 * entry with positive index. We'll go through
 175                 * base->cache[] later to delete all entries in base
 176                 * that are not marked eith either CE_MATCHED or
 177                 * CE_UPDATE_IN_BASE. If istate->cache[i] is a
 178                 * duplicate, deduplicate it.
 179                 */
 180                for (i = 0; i < istate->cache_nr; i++) {
 181                        struct cache_entry *base;
 182                        /* namelen is checked separately */
 183                        const unsigned int ondisk_flags =
 184                                CE_STAGEMASK | CE_VALID | CE_EXTENDED_FLAGS;
 185                        unsigned int ce_flags, base_flags, ret;
 186                        ce = istate->cache[i];
 187                        if (!ce->index)
 188                                continue;
 189                        if (ce->index > si->base->cache_nr) {
 190                                ce->index = 0;
 191                                continue;
 192                        }
 193                        ce->ce_flags |= CE_MATCHED; /* or "shared" */
 194                        base = si->base->cache[ce->index - 1];
 195                        if (ce == base)
 196                                continue;
 197                        if (ce->ce_namelen != base->ce_namelen ||
 198                            strcmp(ce->name, base->name)) {
 199                                ce->index = 0;
 200                                continue;
 201                        }
 202                        ce_flags = ce->ce_flags;
 203                        base_flags = base->ce_flags;
 204                        /* only on-disk flags matter */
 205                        ce->ce_flags   &= ondisk_flags;
 206                        base->ce_flags &= ondisk_flags;
 207                        ret = memcmp(&ce->ce_stat_data, &base->ce_stat_data,
 208                                     offsetof(struct cache_entry, name) -
 209                                     offsetof(struct cache_entry, ce_stat_data));
 210                        ce->ce_flags = ce_flags;
 211                        base->ce_flags = base_flags;
 212                        if (ret)
 213                                ce->ce_flags |= CE_UPDATE_IN_BASE;
 214                        free(base);
 215                        si->base->cache[ce->index - 1] = ce;
 216                }
 217                for (i = 0; i < si->base->cache_nr; i++) {
 218                        ce = si->base->cache[i];
 219                        if ((ce->ce_flags & CE_REMOVE) ||
 220                            !(ce->ce_flags & CE_MATCHED))
 221                                ewah_set(si->delete_bitmap, i);
 222                        else if (ce->ce_flags & CE_UPDATE_IN_BASE) {
 223                                ewah_set(si->replace_bitmap, i);
 224                                ce->ce_flags |= CE_STRIP_NAME;
 225                                ALLOC_GROW(entries, nr_entries+1, nr_alloc);
 226                                entries[nr_entries++] = ce;
 227                        }
 228                }
 229        }
 230
 231        for (i = 0; i < istate->cache_nr; i++) {
 232                ce = istate->cache[i];
 233                if ((!si->base || !ce->index) && !(ce->ce_flags & CE_REMOVE)) {
 234                        assert(!(ce->ce_flags & CE_STRIP_NAME));
 235                        ALLOC_GROW(entries, nr_entries+1, nr_alloc);
 236                        entries[nr_entries++] = ce;
 237                }
 238                ce->ce_flags &= ~CE_MATCHED;
 239        }
 240
 241        /*
 242         * take cache[] out temporarily, put entries[] in its place
 243         * for writing
 244         */
 245        si->saved_cache = istate->cache;
 246        si->saved_cache_nr = istate->cache_nr;
 247        istate->cache = entries;
 248        istate->cache_nr = nr_entries;
 249}
 250
 251void finish_writing_split_index(struct index_state *istate)
 252{
 253        struct split_index *si = init_split_index(istate);
 254
 255        ewah_free(si->delete_bitmap);
 256        ewah_free(si->replace_bitmap);
 257        si->delete_bitmap = NULL;
 258        si->replace_bitmap = NULL;
 259        free(istate->cache);
 260        istate->cache = si->saved_cache;
 261        istate->cache_nr = si->saved_cache_nr;
 262}
 263
 264void discard_split_index(struct index_state *istate)
 265{
 266        struct split_index *si = istate->split_index;
 267        if (!si)
 268                return;
 269        istate->split_index = NULL;
 270        si->refcount--;
 271        if (si->refcount)
 272                return;
 273        if (si->base) {
 274                discard_index(si->base);
 275                free(si->base);
 276        }
 277        free(si);
 278}
 279
 280void save_or_free_index_entry(struct index_state *istate, struct cache_entry *ce)
 281{
 282        if (ce->index &&
 283            istate->split_index &&
 284            istate->split_index->base &&
 285            ce->index <= istate->split_index->base->cache_nr &&
 286            ce == istate->split_index->base->cache[ce->index - 1])
 287                ce->ce_flags |= CE_REMOVE;
 288        else
 289                free(ce);
 290}
 291
 292void replace_index_entry_in_base(struct index_state *istate,
 293                                 struct cache_entry *old,
 294                                 struct cache_entry *new)
 295{
 296        if (old->index &&
 297            istate->split_index &&
 298            istate->split_index->base &&
 299            old->index <= istate->split_index->base->cache_nr) {
 300                new->index = old->index;
 301                if (old != istate->split_index->base->cache[new->index - 1])
 302                        free(istate->split_index->base->cache[new->index - 1]);
 303                istate->split_index->base->cache[new->index - 1] = new;
 304        }
 305}