diff options
| -rw-r--r-- | split-index.c | 89 |
1 files changed, 72 insertions, 17 deletions
diff --git a/split-index.c b/split-index.c index 548272ec33..187b910f5b 100644 --- a/split-index.c +++ b/split-index.c @@ -188,6 +188,30 @@ void merge_base_index(struct index_state *istate) 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); @@ -207,13 +231,28 @@ void prepare_to_write_split_index(struct index_state *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; @@ -227,18 +266,34 @@ void prepare_to_write_split_index(struct index_state *istate) 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) - ce->ce_flags |= CE_UPDATE_IN_BASE; + /* + * 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 { + /* + * 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; } |