config: expose locking via the main API

This lock/unlock pair allows for the cller to lock a configuration file
to avoid concurrent operations.

It also allows for a transactional approach to updating a configuration
file. If multiple updates must be made atomically, they can be done
while the config is locked.

1 files changed, 31 insertions, 0 deletions

diff --git a/src/config.c b/src/config.c
index 77cf573e6..937d00dcb 100644
--- a/src/config.c
+++ b/src/config.c
@@ -1144,6 +1144,37 @@ int git_config_open_default(git_config **out)
 	return error;
 }
 
+int git_config_lock(git_config *cfg)
+{
+	git_config_backend *file;
+	file_internal *internal;
+
+	internal = git_vector_get(&cfg->files, 0);
+	if (!internal || !internal->file) {
+		giterr_set(GITERR_CONFIG, "cannot lock; the config has no backends/files");
+		return -1;
+	}
+	file = internal->file;
+
+	return file->lock(file);
+}
+
+int git_config_unlock(git_config *cfg, int commit)
+{
+	git_config_backend *file;
+	file_internal *internal;
+
+	internal = git_vector_get(&cfg->files, 0);
+	if (!internal || !internal->file) {
+		giterr_set(GITERR_CONFIG, "cannot lock; the config has no backends/files");
+		return -1;
+	}
+
+	file = internal->file;
+
+	return file->unlock(file, commit);
+}
+
 /***********
  * Parsers
  ***********/