repository: introduce a convenience config snapshot method

Accessing the repository's config and immediately taking a snapshot of
it is a common operation, so let's provide a convenience function for
it.

include/git2/repository.h

@@ -409,12 +409,24 @@ GIT_EXTERN(int) git_repository_is_bare(git_repository *repo);
  * The configuration file must be freed once it's no longer
  * being used by the user.
  *
- * @param out Pointer to store the loaded config file
+ * @param out Pointer to store the loaded configuration
  * @param repo A repository object
  * @return 0, or an error code
  */
 GIT_EXTERN(int) git_repository_config(git_config **out, git_repository *repo);
 
+/**
+ * Get a snapshot of the repository's configuration
+ *
+ * Convenience function to take a snapshot from the repository's
+ * configuration.
+ *
+ * @param out Pointer to store the loaded configuration
+ * @param repo the repository
+ * @return 0, or an error code
+ */
+GIT_EXTERN(int) git_repository_config_snapshot(git_config **out, git_repository *repo);
+
 /**
  * Get the Object Database for this repository.
  *

src/branch.c

@@ -332,7 +332,7 @@ int git_branch_upstream_name(
 	int error = -1;
 	git_remote *remote = NULL;
 	const git_refspec *refspec;
-	git_config *config, *repo_config;
+	git_config *config;
 
 	assert(out && refname);
 
@@ -341,10 +341,7 @@ int git_branch_upstream_name(
 	if (!git_reference__is_branch(refname))
 		return not_a_local_branch(refname);
 
-	if ((error = git_repository_config__weakptr(&repo_config, repo)) < 0)
+	if ((error = git_repository_config_snapshot(&config, repo)) < 0)
-		return error;
-
-	if ((error = git_config_snapshot(&config, repo_config)) < 0)
 		return error;
 
 	if ((error = retrieve_upstream_configuration(

src/diff_driver.c

@@ -234,14 +234,11 @@ static int git_diff_driver_load(
 	}
 
 	/* if you can't read config for repo, just use default driver */
-	if (git_repository_config__weakptr(&repo_cfg, repo) < 0) {
+	if (git_repository_config_snapshot(&cfg, repo) < 0) {
 		giterr_clear();
 		goto done;
 	}
 
-	if ((error = git_config_snapshot(&cfg, repo_cfg)) < 0)
-		return error;
-
 	drv = git__calloc(1, sizeof(git_diff_driver) + namelen + 1);
 	GITERR_CHECK_ALLOC(drv);
 	drv->type = DIFF_DRIVER_AUTO;

src/pack-objects.c

@@ -86,14 +86,11 @@ static unsigned name_hash(const char *name)
 
 static int packbuilder_config(git_packbuilder *pb)
 {
-	git_config *config, *repo_config;
+	git_config *config;
 	int ret;
 	int64_t val;
 
-	if ((ret = git_repository_config__weakptr(&repo_config, pb->repo)) < 0)
+	if ((ret = git_repository_config_snapshot(&config, pb->repo)) < 0)
-		return ret;
-
-	if ((ret = git_config_snapshot(&config, repo_config)) < 0)
 		return ret;
 
 #define config_get(KEY,DST,DFLT) do { \

src/remote.c

@@ -347,7 +347,7 @@ int git_remote_load(git_remote **out, git_repository *repo, const char *name)
 	git_buf buf = GIT_BUF_INIT;
 	const char *val;
 	int error = 0;
-	git_config *config, *repo_config;
+	git_config *config;
 	struct refspec_cb_data data = { NULL };
 	bool optional_setting_found = false, found;
 
@@ -356,10 +356,7 @@ int git_remote_load(git_remote **out, git_repository *repo, const char *name)
 	if ((error = ensure_remote_name_is_valid(name)) < 0)
 		return error;
 
-	if (git_repository_config__weakptr(&repo_config, repo) < 0)
+	if ((error = git_repository_config_snapshot(&config, repo)) < 0)
-		return -1;
-
-	if ((error = git_config_snapshot(&config, repo_config)) < 0)
 		return error;
 
 	remote = git__malloc(sizeof(git_remote));

src/repository.c

@@ -439,7 +439,7 @@ int git_repository_open_ext(
 	int error;
 	git_buf path = GIT_BUF_INIT, parent = GIT_BUF_INIT;
 	git_repository *repo;
-	git_config *repo_config, *config;
+	git_config *config;
 
 	if (repo_ptr)
 		*repo_ptr = NULL;
@@ -454,10 +454,7 @@ int git_repository_open_ext(
 	repo->path_repository = git_buf_detach(&path);
 	GITERR_CHECK_ALLOC(repo->path_repository);
 
-	if ((error = git_repository_config__weakptr(&repo_config, repo)) < 0)
+	if ((error = git_repository_config_snapshot(&config, repo)) < 0)
-		return error;
-
-	if ((error = git_config_snapshot(&config, repo_config)) < 0)
 		return error;
 
 	if ((flags & GIT_REPOSITORY_OPEN_BARE) != 0)
@@ -624,6 +621,16 @@ int git_repository_config(git_config **out, git_repository *repo)
 	return 0;
 }
 
+int git_repository_config_snapshot(git_config **out, git_repository *repo)
+{
+	git_config *weak;
+
+	if (git_repository_config__weakptr(&weak, repo) < 0)
+		return -1;
+
+	return git_config_snapshot(out, weak);
+}
+
 void git_repository_set_config(git_repository *repo, git_config *config)
 {
 	assert(repo && config);

src/signature.c

@@ -141,13 +141,10 @@ int git_signature_now(git_signature **sig_out, const char *name, const char *ema
 int git_signature_default(git_signature **out, git_repository *repo)
 {
 	int error;
-	git_config *cfg, *repo_cfg;
+	git_config *cfg;
 	const char *user_name, *user_email;
 
-	if ((error = git_repository_config__weakptr(&repo_cfg, repo)) < 0)
+	if ((error = git_repository_config_snapshot(&cfg, repo)) < 0)
-		return error;
-
-	if ((error = git_config_snapshot(&cfg, repo_cfg)) < 0)
 		return error;
 
 	if (!(error = git_config_get_string(&user_name, cfg, "user.name")) &&