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)
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;
+ } 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;
}