transport: add capabilities query function

include/git2/sys/transport.h

@@ -47,6 +47,16 @@ struct git_transport {
 		const git_remote_connect_options *connect_opts);
 
 	/**
+	 * Gets the capabilities for this remote repository.
+	 *
+	 * This function may be called after a successful call to
+	 * `connect()`.
+	 */
+	int GIT_CALLBACK(capabilities)(
+		unsigned int *capabilities,
+		git_transport *transport);
+
+	/**
 	 * Get the list of available references in the remote repository.
 	 *
 	 * This function may be called after a successful call to

src/transports/local.c

@@ -256,6 +256,14 @@ static int local_set_connect_opts(
 	return git_remote_connect_options_normalize(&t->connect_opts, t->owner->repo, connect_opts);
 }
 
+static int local_capabilities(unsigned int *capabilities, git_transport *transport)
+{
+	GIT_UNUSED(transport);
+
+	*capabilities = 0;
+	return 0;
+}
+
 static int local_ls(const git_remote_head ***out, size_t *size, git_transport *transport)
 {
 	transport_local *t = (transport_local *)transport;
@@ -721,6 +729,7 @@ int git_transport_local(git_transport **out, git_remote *owner, void *param)
 	t->parent.version = GIT_TRANSPORT_VERSION;
 	t->parent.connect = local_connect;
 	t->parent.set_connect_opts = local_set_connect_opts;
+	t->parent.capabilities = local_capabilities;
 	t->parent.negotiate_fetch = local_negotiate_fetch;
 	t->parent.download_pack = local_download_pack;
 	t->parent.push = local_push;

src/transports/smart.c

@@ -226,6 +226,14 @@ static int git_smart__set_connect_opts(
 	return git_remote_connect_options_normalize(&t->connect_opts, t->owner->repo, opts);
 }
 
+static int git_smart__capabilities(unsigned int *capabilities, git_transport *transport)
+{
+	GIT_UNUSED(transport);
+
+	*capabilities = 0;
+	return 0;
+}
+
 static int git_smart__ls(const git_remote_head ***out, size_t *size, git_transport *transport)
 {
 	transport_smart *t = GIT_CONTAINER_OF(transport, transport_smart, parent);
@@ -423,6 +431,7 @@ int git_transport_smart(git_transport **out, git_remote *owner, void *param)
 	t->parent.version = GIT_TRANSPORT_VERSION;
 	t->parent.connect = git_smart__connect;
 	t->parent.set_connect_opts = git_smart__set_connect_opts;
+	t->parent.capabilities = git_smart__capabilities;
 	t->parent.close = git_smart__close;
 	t->parent.free = git_smart__free;
 	t->parent.negotiate_fetch = git_smart__negotiate_fetch;