Merge pull request #472 from libgit2/new-references

References! References! References!

include/git2/refs.h

@@ -23,8 +23,7 @@ GIT_BEGIN_DECL
 /**
  * Lookup a reference by its name in a repository.
  *
- * The generated reference is owned by the repository and
- * should not be freed by the user.
+ * The generated reference must be freed by the user.
  *
  * @param reference_out pointer to the looked-up reference
  * @param repo the repository to look up the reference
@@ -39,8 +38,7 @@ GIT_EXTERN(int) git_reference_lookup(git_reference **reference_out, git_reposito
  * The reference will be created in the repository and written
  * to the disk.
  *
- * This reference is owned by the repository and shall not
- * be free'd by the user.
+ * The generated reference must be freed by the user.
  *
  * If `force` is true and there already exists a reference
  * with the same name, it will be overwritten.
@@ -60,8 +58,7 @@ GIT_EXTERN(int) git_reference_create_symbolic(git_reference **ref_out, git_repos
  * The reference will be created in the repository and written
  * to the disk.
  *
- * This reference is owned by the repository and shall not
- * be free'd by the user.
+ * The generated reference must be freed by the user.
  *
  * If `force` is true and there already exists a reference
  * with the same name, it will be overwritten.
@@ -119,8 +116,13 @@ GIT_EXTERN(const char *) git_reference_name(git_reference *ref);
  * Thie method iteratively peels a symbolic reference
  * until it resolves to a direct reference to an OID.
  *
+ * The peeled reference is returned in the `resolved_ref`
+ * argument, and must be freed manually once it's no longer
+ * needed.
+ *
  * If a direct reference is passed as an argument,
- * that reference is returned immediately
+ * a copy of that reference is returned. This copy must
+ * be manually freed too.
  *
  * @param resolved_ref Pointer to the peeled reference
  * @param ref The reference
@@ -173,9 +175,19 @@ GIT_EXTERN(int) git_reference_set_oid(git_reference *ref, const git_oid *id);
  * The new name will be checked for validity and may be
  * modified into a normalized form.
  *
- * The refernece will be immediately renamed in-memory
+ * The given git_reference will be updated in place.
+ *
+ * The reference will be immediately renamed in-memory
  * and on disk.
  *
+ * If the `force` flag is not enabled, and there's already
+ * a reference with the given name, the renaming will fail.
+ *
+ * @param ref The reference to rename
+ * @param new_name The new name for the reference
+ * @param force Overwrite an existing reference
+ * @return GIT_SUCCESS or an error code
+ *
  */
 GIT_EXTERN(int) git_reference_rename(git_reference *ref, const char *new_name, int force);
 
@@ -187,6 +199,8 @@ GIT_EXTERN(int) git_reference_rename(git_reference *ref, const char *new_name, i
  * The reference will be immediately removed on disk and from
  * memory. The given reference pointer will no longer be valid.
  *
+ * @param ref The reference to remove
+ * @return GIT_SUCCESS or an error code
  */
 GIT_EXTERN(int) git_reference_delete(git_reference *ref);
 
@@ -200,9 +214,6 @@ GIT_EXTERN(int) git_reference_delete(git_reference *ref);
  * Once the `packed-refs` file has been written properly,
  * the loose references will be removed from disk.
  *
- * WARNING: calling this method may invalidate any existing
- * references previously loaded on the cache.
- *
  * @param repo Repository where the loose refs will be packed
  * @return GIT_SUCCESS or an error code
  */
@@ -253,6 +264,41 @@ GIT_EXTERN(int) git_reference_listall(git_strarray *array, git_repository *repo,
  */
 GIT_EXTERN(int) git_reference_foreach(git_repository *repo, unsigned int list_flags, int (*callback)(const char *, void *), void *payload);
 
+/**
+ * Check if a reference has been loaded from a packfile
+ *
+ * @param ref A git reference
+ * @return 0 in case it's not packed; 1 otherwise
+ */
+GIT_EXTERN(int) git_reference_is_packed(git_reference *ref);
+
+/**
+ * Reload a reference from disk
+ *
+ * Reference pointers may become outdated if the Git
+ * repository is accessed simultaneously by other clients
+ * whilt the library is open.
+ *
+ * This method forces a reload of the reference from disk,
+ * to ensure that the provided information is still
+ * reliable.
+ *
+ * If the reload fails (e.g. the reference no longer exists
+ * on disk, or has become corrupted), an error code will be
+ * returned and the reference pointer will be invalidated.
+ *
+ * @param ref The reference to reload
+ * @return GIT_SUCCESS on success, or an error code
+ */
+GIT_EXTERN(int) git_reference_reload(git_reference *ref);
+
+/**
+ * Free the given reference
+ *
+ * @param ref git_reference
+ */
+GIT_EXTERN(void) git_reference_free(git_reference *ref);
+
 /** @} */
 GIT_END_DECL
 #endif

src/commit.c

@@ -137,15 +137,18 @@ int git_commit_create(
 
 	if (error == GIT_SUCCESS && update_ref != NULL) {
 		git_reference *head;
+		git_reference *target;
 
 		error = git_reference_lookup(&head, repo, update_ref);
 		if (error < GIT_SUCCESS)
 			return git__rethrow(error, "Failed to create commit");
 
-		error = git_reference_resolve(&head, head);
+		error = git_reference_resolve(&target, head);
 		if (error < GIT_SUCCESS) {
-			if (error != GIT_ENOTFOUND)
+			if (error != GIT_ENOTFOUND) {
+				git_reference_free(head);
 				return git__rethrow(error, "Failed to create commit");
+			}
 		/*
 		 * The target of the reference was not found. This can happen
 		 * just after a repository has been initialized (the master
@@ -153,10 +156,19 @@ int git_commit_create(
 		 * point to) or after an orphan checkout, so if the target
 		 * branch doesn't exist yet, create it and return.
 		 */
-			return git_reference_create_oid(&head, repo, git_reference_target(head), oid, 1);
+			error = git_reference_create_oid(&target, repo, git_reference_target(head), oid, 1);
+
+			git_reference_free(head);
+			if (error == GIT_SUCCESS)
+				git_reference_free(target);
+
+			return error;
 		}
 
-		error = git_reference_set_oid(head, oid);
+		error = git_reference_set_oid(target, oid);
+
+		git_reference_free(head);
+		git_reference_free(target);
 	}
 
 	if (error < GIT_SUCCESS)

src/reflog.c

@@ -215,23 +215,37 @@ int git_reflog_write(git_reference *ref, const git_oid *oid_old,
 	const git_oid *oid;
 
 	if ((error = git_reference_resolve(&r, ref)) < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to write reflog. Cannot resolve reference `%s`", ref->name);
+		return git__rethrow(error,
+			"Failed to write reflog. Cannot resolve reference `%s`", ref->name);
 
 	oid = git_reference_oid(r);
-	if (oid == NULL)
-		return git__throw(GIT_ERROR, "Failed to write reflog. Cannot resolve reference `%s`", r->name);
+	if (oid == NULL) {
+		git_reference_free(r);
+		return git__throw(GIT_ERROR,
+			"Failed to write reflog. Cannot resolve reference `%s`", r->name);
+	}
 
 	git_oid_to_string(new, GIT_OID_HEXSZ+1, oid);
 
-	git_path_join_n(log_path, 3, ref->owner->path_repository, GIT_REFLOG_DIR, ref->name);
+	git_path_join_n(log_path, 3,
+		ref->owner->path_repository, GIT_REFLOG_DIR, ref->name);
+
+	git_reference_free(r);
 
 	if (git_futils_exists(log_path)) {
-		if ((error = git_futils_mkpath2file(log_path, GIT_REFLOG_DIR_MODE)) < GIT_SUCCESS)
-			return git__rethrow(error, "Failed to write reflog. Cannot create reflog directory");
+		error = git_futils_mkpath2file(log_path, GIT_REFLOG_DIR_MODE);
+		if (error < GIT_SUCCESS)
+			return git__rethrow(error,
+				"Failed to write reflog. Cannot create reflog directory");
+
 	} else if (git_futils_isfile(log_path)) {
-		return git__throw(GIT_ERROR, "Failed to write reflog. `%s` is directory", log_path);
-	} else if (oid_old == NULL)
-		return git__throw(GIT_ERROR, "Failed to write reflog. Old OID cannot be NULL for existing reference");
+		return git__throw(GIT_ERROR,
+			"Failed to write reflog. `%s` is directory", log_path);
+
+	} else if (oid_old == NULL) {
+		return git__throw(GIT_ERROR,
+			"Failed to write reflog. Old OID cannot be NULL for existing reference");
+	}
 
 	if (oid_old)
 		git_oid_to_string(old, GIT_OID_HEXSZ+1, oid_old);

src/refs.h

@@ -33,21 +33,23 @@
 #define GIT_REFNAME_MAX 1024
 
 struct git_reference {
+	unsigned int flags;
 	git_repository *owner;
 	char *name;
-	unsigned int type;
 	time_t mtime;
+
+	union {
+		git_oid oid;
+		char *symbolic;
+	} target;
 };
 
 typedef struct {
 	git_hashtable *packfile;
-	git_hashtable *loose_cache;
 	time_t packfile_time;
 } git_refcache;
 
-
 void git_repository__refcache_free(git_refcache *refs);
-int git_repository__refcache_init(git_refcache *refs);
 
 int git_reference__normalize_name(char *buffer_out, size_t out_size, const char *name);
 int git_reference__normalize_name_oid(char *buffer_out, size_t out_size, const char *name);

src/repository.c

@@ -172,11 +172,6 @@ static git_repository *repository_alloc(void)
 		return NULL;
 	}
 
-	if (git_repository__refcache_init(&repo->references) < GIT_SUCCESS) {
-		git__free(repo);
-		return NULL;
-	}
-
 	return repo;
 }
 
@@ -603,8 +598,14 @@ static int repo_init_reinit(const char *repository_path, int is_bare)
 
 static int repo_init_createhead(git_repository *repo)
 {
+	int error;
 	git_reference *head_reference;
-	return git_reference_create_symbolic(&head_reference, repo, GIT_HEAD_FILE, GIT_REFS_HEADS_MASTER_FILE, 0);
+
+	error = git_reference_create_symbolic(&head_reference, repo, GIT_HEAD_FILE, GIT_REFS_HEADS_MASTER_FILE, 0);
+
+	git_reference_free(head_reference);
+
+	return error;
 }
 
 static int repo_init_structure(const char *git_dir, int is_bare)
@@ -715,10 +716,15 @@ int git_repository_head_detached(git_repository *repo)
 	if (error < GIT_SUCCESS)
 		return error;
 
-	if (git_reference_type(ref) == GIT_REF_SYMBOLIC)
+	if (git_reference_type(ref) == GIT_REF_SYMBOLIC) {
+		git_reference_free(ref);
 		return 0;
+	}
 
 	error = git_odb_read_header(&_size, &type, repo->db, git_reference_oid(ref));
+
+	git_reference_free(ref);
+
 	if (error < GIT_SUCCESS)
 		return error;
 
@@ -730,7 +736,7 @@ int git_repository_head_detached(git_repository *repo)
 
 int git_repository_head(git_reference **head_out, git_repository *repo)
 {
-	git_reference *ref;
+	git_reference *ref, *resolved_ref;
 	int error;
 
 	*head_out = NULL;
@@ -739,11 +745,15 @@ int git_repository_head(git_reference **head_out, git_repository *repo)
 	if (error < GIT_SUCCESS)
 		return git__rethrow(GIT_ENOTAREPO, "Failed to locate the HEAD");
 
-	error = git_reference_resolve(&ref, ref);
-	if (error < GIT_SUCCESS)
+	error = git_reference_resolve(&resolved_ref, ref);
+	if (error < GIT_SUCCESS) {
+		git_reference_free(ref);
 		return git__rethrow(error, "Failed to resolve the HEAD");
+	}
+
+	git_reference_free(ref);
 
-	*head_out = ref;
+	*head_out = resolved_ref;
 	return GIT_SUCCESS;
 }
 
@@ -754,25 +764,36 @@ int git_repository_head_orphan(git_repository *repo)
 
 	error = git_repository_head(&ref, repo);
 
+	if (error == GIT_SUCCESS)
+		git_reference_free(ref);
+
 	return error == GIT_ENOTFOUND ? 1 : error;
 }
 
 int git_repository_is_empty(git_repository *repo)
 {
-	git_reference *head, *branch;
+	git_reference *head = NULL, *branch = NULL;
 	int error;
 
 	error = git_reference_lookup(&head, repo, "HEAD");
 	if (error < GIT_SUCCESS)
 		return git__throw(error, "Corrupted repository. HEAD does not exist");
 
-	if (git_reference_type(head) != GIT_REF_SYMBOLIC)
+	if (git_reference_type(head) != GIT_REF_SYMBOLIC) {
+		git_reference_free(head);
 		return 0;
+	}
 
-	if (strcmp(git_reference_target(head), "refs/heads/master") != 0)
+	if (strcmp(git_reference_target(head), "refs/heads/master") != 0) {
+		git_reference_free(head);
 		return 0;
+	}
 
 	error = git_reference_resolve(&branch, head);
+
+	git_reference_free(head);
+	git_reference_free(branch);
+
 	return error == GIT_ENOTFOUND ? 1 : error;
 }
 

src/tag.c

@@ -153,6 +153,8 @@ static int retrieve_tag_reference(git_reference **tag_reference_out, char *ref_n
 	git_reference *tag_ref;
 	int error;
 
+	*tag_reference_out = NULL;
+
 	git_path_join(ref_name_out, GIT_REFS_TAGS_DIR, tag_name);
 	error = git_reference_lookup(&tag_ref, repo, ref_name_out);
 	if (error < GIT_SUCCESS)
@@ -224,6 +226,7 @@ static int git_tag_create__internal(
 			break;
 
 		default:
+			git_reference_free(new_ref);
 			return git__rethrow(error, "Failed to create tag");
 	}
 
@@ -232,6 +235,7 @@ static int git_tag_create__internal(
 	if (new_ref != NULL) {
 		if (!allow_ref_overwrite) {
 			git_oid_cpy(oid, git_reference_oid(new_ref));
+			git_reference_free(new_ref);
 			return git__throw(GIT_EEXISTS, "Tag already exists");
 		} else {
 			should_update_ref = 1;
@@ -239,8 +243,10 @@ static int git_tag_create__internal(
 	}
 
 	if (create_tag_annotation) {
-		if ((error = write_tag_annotation(oid, repo, tag_name, target, tagger, message)) < GIT_SUCCESS)
+		if ((error = write_tag_annotation(oid, repo, tag_name, target, tagger, message)) < GIT_SUCCESS) {
+			git_reference_free(new_ref);
 			return error;
+		}
 	} else
 		git_oid_cpy(oid, git_object_id(target));
 
@@ -249,6 +255,8 @@ static int git_tag_create__internal(
 	else
 		error = git_reference_set_oid(new_ref, oid);
 
+	git_reference_free(new_ref);
+
 	return error == GIT_SUCCESS ? GIT_SUCCESS : git__rethrow(error, "Failed to create tag");
 }
 
@@ -281,7 +289,7 @@ int git_tag_create_frombuffer(git_oid *oid, git_repository *repo, const char *bu
 	git_odb_stream *stream;
 	git_odb_object *target_obj;
 
-	git_reference *new_ref;
+	git_reference *new_ref = NULL;
 	char ref_name[GIT_REFNAME_MAX];
 
 	assert(oid && buffer);
@@ -309,6 +317,7 @@ int git_tag_create_frombuffer(git_oid *oid, git_repository *repo, const char *bu
 			break;
 
 		default:
+			git_reference_free(new_ref);
 			return git__rethrow(error, "Failed to create tag");
 	}
 
@@ -317,6 +326,7 @@ int git_tag_create_frombuffer(git_oid *oid, git_repository *repo, const char *bu
 	if (new_ref != NULL) {
 		if (!allow_ref_overwrite) {
 			git_oid_cpy(oid, git_reference_oid(new_ref));
+			git_reference_free(new_ref);
 			return git__throw(GIT_EEXISTS, "Tag already exists");
 		} else {
 			should_update_ref = 1;
@@ -324,22 +334,28 @@ int git_tag_create_frombuffer(git_oid *oid, git_repository *repo, const char *bu
 	}
 
 	/* write the buffer */
-	if ((error = git_odb_open_wstream(&stream, repo->db, strlen(buffer), GIT_OBJ_TAG)) < GIT_SUCCESS)
+	if ((error = git_odb_open_wstream(&stream, repo->db, strlen(buffer), GIT_OBJ_TAG)) < GIT_SUCCESS) {
+		git_reference_free(new_ref);
 		return git__rethrow(error, "Failed to create tag");
+	}
 
 	stream->write(stream, buffer, strlen(buffer));
 
 	error = stream->finalize_write(oid, stream);
 	stream->free(stream);
 
-	if (error < GIT_SUCCESS)
+	if (error < GIT_SUCCESS) {
+		git_reference_free(new_ref);
 		return git__rethrow(error, "Failed to create tag");
+	}
 
 	if (!should_update_ref)
 		error = git_reference_create_oid(&new_ref, repo, ref_name, oid, 0);
 	else
 		error = git_reference_set_oid(new_ref, oid);
 
+	git_reference_free(new_ref);
+
 	git_signature_free(tag.tagger);
 	git__free(tag.tag_name);
 	git__free(tag.message);

src/transports/local.c

@@ -54,7 +54,7 @@ static int add_ref(const char *name, git_repository *repo, git_vector *vec)
 {
 	const char peeled[] = "^{}";
 	git_remote_head *head;
-	git_reference *ref;
+	git_reference *ref, *resolved_ref;
 	git_object *obj = NULL;
 	int error = GIT_SUCCESS, peel_len, ret;
 
@@ -72,7 +72,7 @@ static int add_ref(const char *name, git_repository *repo, git_vector *vec)
 	if (error < GIT_SUCCESS)
 		goto out;
 
-	error = git_reference_resolve(&ref, ref);
+	error = git_reference_resolve(&resolved_ref, ref);
 	if (error < GIT_SUCCESS)
 		goto out;
 
@@ -111,6 +111,9 @@ static int add_ref(const char *name, git_repository *repo, git_vector *vec)
 		goto out;
 
  out:
+	git_reference_free(ref);
+	git_reference_free(resolved_ref);
+
 	git_object_close(obj);
 	if (error < GIT_SUCCESS) {
 		git__free(head->name);

tests/t04-commit.c

@@ -766,6 +766,8 @@ BEGIN_TEST(root0, "create a root commit")
 	git__free(head_old);
 	git_commit_close(commit);
 	git_repository_free(repo);
+
+	git_reference_free(head);
 END_TEST
 
 BEGIN_SUITE(commit)

tests/t08-tag.c

@@ -197,7 +197,6 @@ BEGIN_TEST(write0, "write a tag to the repository and read it again")
 
 	git_tag_close(tag);
 	git_repository_free(repo);
-
 END_TEST
 
 BEGIN_TEST(write2, "Attempt to write a tag bearing the same name than an already existing tag")
@@ -266,6 +265,7 @@ BEGIN_TEST(write3, "Replace an already existing tag")
 
 	close_temp_repo(repo);
 
+	git_reference_free(ref_tag);
 END_TEST
 
 BEGIN_TEST(write4, "write a lightweight tag to the repository and read it again")
@@ -296,6 +296,8 @@ BEGIN_TEST(write4, "write a lightweight tag to the repository and read it again"
 	must_pass(git_tag_delete(repo, "light-tag"));
 
 	git_repository_free(repo);
+
+	git_reference_free(ref_tag);
 END_TEST
 
 BEGIN_TEST(write5, "Attempt to write a lightweight tag bearing the same name than an already existing tag")
@@ -334,6 +336,8 @@ BEGIN_TEST(delete0, "Delete an already existing tag")
 	must_fail(git_reference_lookup(&ref_tag, repo, "refs/tags/e90810b"));
 
 	close_temp_repo(repo);
+
+	git_reference_free(ref_tag);
 END_TEST
 
 BEGIN_SUITE(tag)

tests/t12-repo.c

@@ -286,6 +286,8 @@ BEGIN_TEST(detached0, "test if HEAD is detached")
 	must_be_true(git_repository_head_detached(repo) == 0);
 
 	git_repository_free(repo);
+
+	git_reference_free(ref);
 END_TEST
 
 BEGIN_TEST(orphan0, "test if HEAD is orphan")
@@ -305,6 +307,8 @@ BEGIN_TEST(orphan0, "test if HEAD is orphan")
 	must_be_true(git_repository_head_orphan(repo) == 0);
 
 	git_repository_free(repo);
+
+	git_reference_free(ref);
 END_TEST
 
 #define DISCOVER_FOLDER TEMP_REPO_FOLDER "discover.git"