index: write out the tree cache extension

Keeping the cache around after read-tree is only one part of the
optimisation opportunities. In order to share the cache between program
instances, we need to write the TREE extension to the index.

Do so, taking the opportunity to rename 'entries' to 'entry_count' to
match the name given in the format description. The included test is
rather trivial, but works as a sanity check.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/tree-cache.h b/src/tree-cache.h
index b92a401a6..c44ca7cf5 100644
--- a/src/tree-cache.h
+++ b/src/tree-cache.h
@@ -10,18 +10,20 @@
 
 #include "common.h"
 #include "pool.h"
+#include "buffer.h"
 #include "git2/oid.h"
 
 typedef struct git_tree_cache {
 	struct git_tree_cache **children;
 	size_t children_count;
 
-	ssize_t entries;
+	ssize_t entry_count;
 	git_oid oid;
 	size_t namelen;
 	char name[GIT_FLEX_ARRAY];
 } git_tree_cache;
 
+int git_tree_cache_write(git_buf *out, git_tree_cache *tree);
 int git_tree_cache_read(git_tree_cache **tree, const char *buffer, size_t buffer_size, git_pool *pool);
 void git_tree_cache_invalidate_path(git_tree_cache *tree, const char *path);
 const git_tree_cache *git_tree_cache_get(const git_tree_cache *tree, const char *path);