Only enqueue messages when the engine is remote

When the engine is local, messages are emitted in the Gtk thread and applied
immediately.  This should make the GUI more responsive.

1 files changed, 66 insertions, 0 deletions

diff --git a/ingen/QueuedInterface.hpp b/ingen/QueuedInterface.hpp
new file mode 100644
index 00000000..bf424edd
--- /dev/null
+++ b/ingen/QueuedInterface.hpp
@@ -0,0 +1,66 @@
+/*
+  This file is part of Ingen.
+  Copyright 2018 David Robillard <http://drobilla.net/>
+
+  Ingen is free software: you can redistribute it and/or modify it under the
+  terms of the GNU Affero General Public License as published by the Free
+  Software Foundation, either version 3 of the License, or any later version.
+
+  Ingen is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for details.
+
+  You should have received a copy of the GNU Affero General Public License
+  along with Ingen.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef INGEN_ENGINE_QUEUEDINTERFACE_HPP
+#define INGEN_ENGINE_QUEUEDINTERFACE_HPP
+
+#include <mutex>
+#include <vector>
+
+#include "ingen/Interface.hpp"
+#include "ingen/Message.hpp"
+
+namespace Ingen {
+
+/** Stores all messages and emits them to a sink on demand.
+ *
+ * This can be used to make an interface thread-safe.
+ */
+class QueuedInterface : public Interface
+{
+public:
+	explicit QueuedInterface(SPtr<Interface> sink) : _sink(std::move(sink)) {}
+
+	URI uri() const override { return URI("ingen:/QueuedInterface"); }
+
+	void message(const Message& message) override {
+		std::lock_guard<std::mutex> lock(_mutex);
+		_messages.emplace_back(message);
+	}
+
+	void emit() {
+		std::vector<Message> messages;
+		{
+			std::lock_guard<std::mutex> lock(_mutex);
+			_messages.swap(messages);
+		}
+
+		for (const auto& i : messages) {
+			_sink->message(i);
+		}
+	}
+
+	const SPtr<Interface>& sink() const { return _sink; }
+
+private:
+	std::mutex           _mutex;
+	SPtr<Interface>      _sink;
+	std::vector<Message> _messages;
+};
+
+} // namespace Ingen
+
+#endif // INGEN_ENGINE_QUEUEDINTERFACE_HPP