Make refcounting atomic

src/util.h

@@ -188,20 +188,20 @@ extern int git__strncmp(const char *a, const char *b, size_t sz);
 extern int git__strncasecmp(const char *a, const char *b, size_t sz);
 
 typedef struct {
-	short refcount;
+	git_atomic refcount;
 	void *owner;
 } git_refcount;
 
 typedef void (*git_refcount_freeptr)(void *r);
 
 #define GIT_REFCOUNT_INC(r) { \
-	((git_refcount *)(r))->refcount++; \
+	git_atomic_inc(&((git_refcount *)(r))->refcount);	\
 }
 
 #define GIT_REFCOUNT_DEC(_r, do_free) { \
 	git_refcount *r = (git_refcount *)(_r); \
-	r->refcount--; \
-	if (r->refcount <= 0 && r->owner == NULL) { do_free(_r); } \
+	int val = git_atomic_dec(&r->refcount); \
+	if (val <= 0 && r->owner == NULL) { do_free(_r); } \
 }
 
 #define GIT_REFCOUNT_OWN(r, o) { \

tests-clar/repo/getters.c

@@ -31,10 +31,10 @@ void test_repo_getters__retrieving_the_odb_honors_the_refcount(void)
 	cl_git_pass(git_repository_open(&repo, cl_fixture("testrepo.git")));
 
 	cl_git_pass(git_repository_odb(&odb, repo));
-	cl_assert(((git_refcount *)odb)->refcount == 2);
+	cl_assert(((git_refcount *)odb)->refcount.val == 2);
 
 	git_repository_free(repo);
-	cl_assert(((git_refcount *)odb)->refcount == 1);
+	cl_assert(((git_refcount *)odb)->refcount.val == 1);
 
 	git_odb_free(odb);
 }

tests-clar/repo/setters.c

@@ -69,13 +69,13 @@ void test_repo_setters__setting_a_new_index_on_a_repo_which_has_already_loaded_o
 	git_index *new_index;
 
 	cl_git_pass(git_index_open(&new_index, "./my-index"));
-	cl_assert(((git_refcount *)new_index)->refcount == 1);
+	cl_assert(((git_refcount *)new_index)->refcount.val == 1);
 
 	git_repository_set_index(repo, new_index);
-	cl_assert(((git_refcount *)new_index)->refcount == 2);
+	cl_assert(((git_refcount *)new_index)->refcount.val == 2);
 
 	git_repository_free(repo);
-	cl_assert(((git_refcount *)new_index)->refcount == 1);
+	cl_assert(((git_refcount *)new_index)->refcount.val == 1);
 
 	git_index_free(new_index);
 
@@ -90,13 +90,13 @@ void test_repo_setters__setting_a_new_odb_on_a_repo_which_already_loaded_one_pro
 	git_odb *new_odb;
 
 	cl_git_pass(git_odb_open(&new_odb, "./testrepo.git/objects"));
-	cl_assert(((git_refcount *)new_odb)->refcount == 1);
+	cl_assert(((git_refcount *)new_odb)->refcount.val == 1);
 
 	git_repository_set_odb(repo, new_odb);
-	cl_assert(((git_refcount *)new_odb)->refcount == 2);
+	cl_assert(((git_refcount *)new_odb)->refcount.val == 2);
 
 	git_repository_free(repo);
-	cl_assert(((git_refcount *)new_odb)->refcount == 1);
+	cl_assert(((git_refcount *)new_odb)->refcount.val == 1);
 
 	git_odb_free(new_odb);