split-index: add and use unshare_split_index()

When split-index is being used, we have two cache_entry arrays in
index_state->cache[] and index_state->split_index->base->cache[].

index_state->cache[] may share the same entries with base->cache[] so
we can quickly determine what entries are shared. This makes memory
management tricky, we can't free base->cache[] until we know
index_state->cache[] does not point to any of those entries.

unshare_split_index() is added for this purpose, to find shared
entries and either duplicate them in index_state->cache[], or discard
them. Either way it should be safe to free base->cache[] after
unshare_split_index().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Nguyễn Thái Ngọc Duy
2017-05-05 16:57:12 +02:00
committed by Junio C Hamano
parent 4fa66c85f1
commit f9d7abec2a
3 changed files with 47 additions and 21 deletions

View File

@ -33,5 +33,6 @@ void finish_writing_split_index(struct index_state *istate);
void discard_split_index(struct index_state *istate);
void add_split_index(struct index_state *istate);
void remove_split_index(struct index_state *istate);
void unshare_split_index(struct index_state *istate, int discard);
#endif