[PATCH 2/4] pack v4: add v4_size to struct delta_base_cache_entry

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

The intention is to store flat v4 trees in delta base cache to avoid
repeatedly expanding copy sequences in v4 trees. When the user needs
to unpack a v4 tree and the tree is found in the cache, the tree will
be converted back to canonical format. Future tree_desc interface may
skip canonical format and read v4 trees directly.

For that to work we need to keep track of v4 tree size after all copy
sequences are expanded, which is the purpose of this new field.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 sha1_file.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sha1_file.c b/sha1_file.c
index 038e22e..03c66bb 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1934,6 +1934,7 @@ static struct delta_base_cache_entry {
 	struct packed_git *p;
 	off_t base_offset;
 	unsigned long size;
+	unsigned long v4_size;
 	enum object_type type;
 } delta_base_cache[MAX_DELTA_CACHE];
 
@@ -2015,7 +2016,8 @@ void clear_delta_base_cache(void)
 }
 
 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
-	void *base, unsigned long base_size, enum object_type type)
+	void *base, unsigned long base_size, unsigned long v4_size,
+	enum object_type type)
 {
 	unsigned long hash = pack_entry_hash(p, base_offset);
 	struct delta_base_cache_entry *ent = delta_base_cache + hash;
@@ -2045,6 +2047,7 @@ static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
 	ent->type = type;
 	ent->data = base;
 	ent->size = base_size;
+	ent->v4_size = v4_size;
 	ent->lru.next = &delta_base_cache_lru;
 	ent->lru.prev = delta_base_cache_lru.prev;
 	delta_base_cache_lru.prev->next = &ent->lru;
@@ -2208,7 +2211,7 @@ void *unpack_entry(struct packed_git *p, off_t obj_offset,
 		data = NULL;
 
 		if (base)
-			add_delta_base_cache(p, obj_offset, base, base_size, type);
+			add_delta_base_cache(p, obj_offset, base, base_size, 0, type);
 
 		if (!base) {
 			/*
-- 
1.8.2.83.gc99314b