struct split_index *si;
int ret;
- if (sz < 20)
+ if (sz < the_hash_algo->rawsz)
return error("corrupt link extension (too short)");
si = init_split_index(istate);
- hashcpy(si->base_sha1, data);
- data += 20;
- sz -= 20;
+ hashcpy(si->base_oid.hash, data);
+ data += the_hash_algo->rawsz;
+ sz -= the_hash_algo->rawsz;
if (!sz)
return 0;
si->delete_bitmap = ewah_new();
struct index_state *istate)
{
struct split_index *si = istate->split_index;
- strbuf_add(sb, si->base_sha1, 20);
+ strbuf_add(sb, si->base_oid.hash, the_hash_algo->rawsz);
if (!si->delete_bitmap && !si->replace_bitmap)
return 0;
ewah_serialize_strbuf(si->delete_bitmap, sb);
int i;
/*
- * do not delete old si->base, its index entries may be shared
- * with istate->cache[]. Accept a bit of leaking here because
- * this code is only used by short-lived update-index.
+ * If there was a previous base index, then transfer ownership of allocated
+ * entries to the parent index.
*/
+ if (si->base &&
+ si->base->ce_mem_pool) {
+
+ if (!istate->ce_mem_pool)
+ mem_pool_init(&istate->ce_mem_pool, 0);
+
+ mem_pool_combine(istate->ce_mem_pool, istate->split_index->base->ce_mem_pool);
+ }
+
si->base = xcalloc(1, sizeof(*si->base));
si->base->version = istate->version;
/* zero timestamp disables racy test in ce_write_index() */
si->base->timestamp = istate->timestamp;
ALLOC_GROW(si->base->cache, istate->cache_nr, si->base->cache_alloc);
si->base->cache_nr = istate->cache_nr;
+
+ /*
+ * The mem_pool needs to move with the allocated entries.
+ */
+ si->base->ce_mem_pool = istate->ce_mem_pool;
+ istate->ce_mem_pool = NULL;
+
COPY_ARRAY(si->base->cache, istate->cache, istate->cache_nr);
mark_base_index_entries(si->base);
for (i = 0; i < si->base->cache_nr; i++)
die("position for delete %d exceeds base index size %d",
(int)pos, istate->cache_nr);
istate->cache[pos]->ce_flags |= CE_REMOVE;
- istate->split_index->nr_deletions = 1;
+ istate->split_index->nr_deletions++;
}
static void replace_entry(size_t pos, void *data)
src->ce_flags |= CE_UPDATE_IN_BASE;
src->ce_namelen = dst->ce_namelen;
copy_cache_entry(dst, src);
- free(src);
+ discard_cache_entry(src);
si->nr_replacements++;
}
si->saved_cache_nr = 0;
}
+/*
+ * Compare most of the fields in two cache entries, i.e. all except the
+ * hashmap_entry and the name.
+ */
+static int compare_ce_content(struct cache_entry *a, struct cache_entry *b)
+{
+ const unsigned int ondisk_flags = CE_STAGEMASK | CE_VALID |
+ CE_EXTENDED_FLAGS;
+ unsigned int ce_flags = a->ce_flags;
+ unsigned int base_flags = b->ce_flags;
+ int ret;
+
+ /* only on-disk flags matter */
+ a->ce_flags &= ondisk_flags;
+ b->ce_flags &= ondisk_flags;
+ ret = memcmp(&a->ce_stat_data, &b->ce_stat_data,
+ offsetof(struct cache_entry, name) -
+ offsetof(struct cache_entry, ce_stat_data));
+ a->ce_flags = ce_flags;
+ b->ce_flags = base_flags;
+
+ return ret;
+}
+
void prepare_to_write_split_index(struct index_state *istate)
{
struct split_index *si = init_split_index(istate);
*/
for (i = 0; i < istate->cache_nr; i++) {
struct cache_entry *base;
- /* namelen is checked separately */
- const unsigned int ondisk_flags =
- CE_STAGEMASK | CE_VALID | CE_EXTENDED_FLAGS;
- unsigned int ce_flags, base_flags, ret;
ce = istate->cache[i];
- if (!ce->index)
+ if (!ce->index) {
+ /*
+ * During simple update index operations this
+ * is a cache entry that is not present in
+ * the shared index. It will be added to the
+ * split index.
+ *
+ * However, it might also represent a file
+ * that already has a cache entry in the
+ * shared index, but a new index has just
+ * been constructed by unpack_trees(), and
+ * this entry now refers to different content
+ * than what was recorded in the original
+ * index, e.g. during 'read-tree -m HEAD^' or
+ * 'checkout HEAD^'. In this case the
+ * original entry in the shared index will be
+ * marked as deleted, and this entry will be
+ * added to the split index.
+ */
continue;
+ }
if (ce->index > si->base->cache_nr) {
- ce->index = 0;
- continue;
+ BUG("ce refers to a shared ce at %d, which is beyond the shared index size %d",
+ ce->index, si->base->cache_nr);
}
ce->ce_flags |= CE_MATCHED; /* or "shared" */
base = si->base->cache[ce->index - 1];
- if (ce == base)
+ if (ce == base) {
+ /* The entry is present in the shared index. */
+ if (ce->ce_flags & CE_UPDATE_IN_BASE) {
+ /*
+ * Already marked for inclusion in
+ * the split index, either because
+ * the corresponding file was
+ * modified and the cached stat data
+ * was refreshed, or because there
+ * is already a replacement entry in
+ * the split index.
+ * Nothing more to do here.
+ */
+ } else if (!ce_uptodate(ce) &&
+ is_racy_timestamp(istate, ce)) {
+ /*
+ * A racily clean cache entry stored
+ * only in the shared index: it must
+ * be added to the split index, so
+ * the subsequent do_write_index()
+ * can smudge its stat data.
+ */
+ ce->ce_flags |= CE_UPDATE_IN_BASE;
+ } else {
+ /*
+ * The entry is only present in the
+ * shared index and it was not
+ * refreshed.
+ * Just leave it there.
+ */
+ }
continue;
+ }
if (ce->ce_namelen != base->ce_namelen ||
strcmp(ce->name, base->name)) {
ce->index = 0;
continue;
}
- ce_flags = ce->ce_flags;
- base_flags = base->ce_flags;
- /* only on-disk flags matter */
- ce->ce_flags &= ondisk_flags;
- base->ce_flags &= ondisk_flags;
- ret = memcmp(&ce->ce_stat_data, &base->ce_stat_data,
- offsetof(struct cache_entry, name) -
- offsetof(struct cache_entry, ce_stat_data));
- ce->ce_flags = ce_flags;
- base->ce_flags = base_flags;
- if (ret)
+ /*
+ * This is the copy of a cache entry that is present
+ * in the shared index, created by unpack_trees()
+ * while it constructed a new index.
+ */
+ if (ce->ce_flags & CE_UPDATE_IN_BASE) {
+ /*
+ * Already marked for inclusion in the split
+ * index, either because the corresponding
+ * file was modified and the cached stat data
+ * was refreshed, or because the original
+ * entry already had a replacement entry in
+ * the split index.
+ * Nothing to do.
+ */
+ } else if (!ce_uptodate(ce) &&
+ is_racy_timestamp(istate, ce)) {
+ /*
+ * A copy of a racily clean cache entry from
+ * the shared index. It must be added to
+ * the split index, so the subsequent
+ * do_write_index() can smudge its stat data.
+ */
ce->ce_flags |= CE_UPDATE_IN_BASE;
- free(base);
+ } else {
+ /*
+ * Thoroughly compare the cached data to see
+ * whether it should be marked for inclusion
+ * in the split index.
+ *
+ * This comparison might be unnecessary, as
+ * code paths modifying the cached data do
+ * set CE_UPDATE_IN_BASE as well.
+ */
+ if (compare_ce_content(ce, base))
+ ce->ce_flags |= CE_UPDATE_IN_BASE;
+ }
+ discard_cache_entry(base);
si->base->cache[ce->index - 1] = ce;
}
for (i = 0; i < si->base->cache_nr; i++) {
ce == istate->split_index->base->cache[ce->index - 1])
ce->ce_flags |= CE_REMOVE;
else
- free(ce);
+ discard_cache_entry(ce);
}
void replace_index_entry_in_base(struct index_state *istate,
old_entry->index <= istate->split_index->base->cache_nr) {
new_entry->index = old_entry->index;
if (old_entry != istate->split_index->base->cache[new_entry->index - 1])
- free(istate->split_index->base->cache[new_entry->index - 1]);
+ discard_cache_entry(istate->split_index->base->cache[new_entry->index - 1]);
istate->split_index->base->cache[new_entry->index - 1] = new_entry;
}
}
{
if (istate->split_index) {
/*
- * can't discard_split_index(&the_index); because that
- * will destroy split_index->base->cache[], which may
- * be shared with the_index.cache[]. So yeah we're
- * leaking a bit here.
+ * When removing the split index, we need to move
+ * ownership of the mem_pool associated with the
+ * base index to the main index. There may be cache entries
+ * allocated from the base's memory pool that are shared with
+ * the_index.cache[].
+ */
+ mem_pool_combine(istate->ce_mem_pool, istate->split_index->base->ce_mem_pool);
+
+ /*
+ * The split index no longer owns the mem_pool backing
+ * its cache array. As we are discarding this index,
+ * mark the index as having no cache entries, so it
+ * will not attempt to clean up the cache entries or
+ * validate them.
*/
- istate->split_index = NULL;
+ if (istate->split_index->base)
+ istate->split_index->base->cache_nr = 0;
+
+ /*
+ * We can discard the split index because its
+ * memory pool has been incorporated into the
+ * memory pool associated with the the_index.
+ */
+ discard_split_index(istate);
+
istate->cache_changed |= SOMETHING_CHANGED;
}
}