Make a real submodule cache object

This takes the old submodule cache which was just a git_strmap
and makes a real git_submodule_cache object that can contain other
things like a lock and timestamp-ish data to control refreshing of
submodule info.

src/repository.c

@@ -93,6 +93,7 @@ void git_repository__cleanup(git_repository *repo)
 
 	git_cache_clear(&repo->objects);
 	git_attr_cache_flush(repo);
+	git_submodule_cache_free(repo);
 
 	set_config(repo, NULL);
 	set_index(repo, NULL);
@@ -108,7 +109,6 @@ void git_repository_free(git_repository *repo)
 	git_repository__cleanup(repo);
 
 	git_cache_free(&repo->objects);
-	git_submodule_config_free(repo);
 
 	git_diff_driver_registry_free(repo->diff_drivers);
 	repo->diff_drivers = NULL;

src/repository.h

@@ -19,7 +19,7 @@
 #include "buffer.h"
 #include "object.h"
 #include "attrcache.h"
-#include "strmap.h"
+#include "submodule.h"
 #include "diff_driver.h"
 
 #define DOT_GIT ".git"
@@ -105,10 +105,10 @@ struct git_repository {
 	git_refdb *_refdb;
 	git_config *_config;
 	git_index *_index;
+	git_submodule_cache *_submodules;
 
 	git_cache objects;
 	git_attr_cache attrcache;
-	git_strmap *submodules;
 	git_diff_driver_registry *diff_drivers;
 
 	char *path_repository;
@@ -149,11 +149,6 @@ int git_repository_index__weakptr(git_index **out, git_repository *repo);
 int git_repository__cvar(int *out, git_repository *repo, git_cvar_cached cvar);
 void git_repository__cvar_cache_clear(git_repository *repo);
 
-/*
- * Submodule cache
- */
-extern void git_submodule_config_free(git_repository *repo);
-
 GIT_INLINE(int) git_repository__ensure_not_bare(
 	git_repository *repo,
 	const char *operation_name)

src/submodule.h

@@ -99,6 +99,30 @@ struct git_submodule {
 	git_oid wd_oid;
 };
 
+/**
+ * The git_submodule_cache stores known submodules along with timestamps,
+ * etc. about when they were loaded
+ */
+typedef struct {
+	git_repository *repo;
+	git_strmap *submodules;
+	git_mutex  lock;
+
+	/* cache invalidation data */
+	git_oid head_id;
+	git_futils_filestamp index_stamp;
+	git_buf gitmodules_path;
+	git_futils_filestamp gitmodules_stamp;
+	git_oid gitmodules_id;
+	git_futils_filestamp config_stamp;
+} git_submodule_cache;
+
+/* Force revalidation of submodule data cache (alloc as needed) */
+extern int git_submodule_cache_refresh(git_repository *repo);
+
+/* Release all submodules */
+extern void git_submodule_cache_free(git_repository *repo);
+
 /* Additional flags on top of public GIT_SUBMODULE_STATUS values */
 enum {
 	GIT_SUBMODULE_STATUS__WD_SCANNED          = (1u << 20),
@@ -122,6 +146,10 @@ enum {
 /* Internal submodule check does not attempt to refresh cached data */
 extern bool git_submodule__is_submodule(git_repository *repo, const char *name);
 
+/* Internal lookup does not attempt to refresh cached data */
+extern int git_submodule__lookup(
+	git_submodule **out, git_repository *repo, const char *path);
+
 /* Internal status fn returns status and optionally the various OIDs */
 extern int git_submodule__status(
 	unsigned int *out_status,
@@ -143,5 +171,6 @@ extern int git_submodule_parse_update(
 
 extern const char *git_submodule_ignore_to_str(git_submodule_ignore_t);
 extern const char *git_submodule_update_to_str(git_submodule_update_t);
+extern const char *git_submodule_recurse_to_str(git_submodule_recurse_t);
 
 #endif