Rename UISignaller -> SignalManager.

1 files changed, 90 insertions, 0 deletions

diff --git a/src/lib/signal_manager.h b/src/lib/signal_manager.h
new file mode 100644
index 000000000..ae4306e30
--- /dev/null
+++ b/src/lib/signal_manager.h
@@ -0,0 +1,90 @@
+/*
+    Copyright (C) 2012-2015 Carl Hetherington <cth@carlh.net>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#ifndef DCPOMATIC_SIGNAL_MANAGER_H
+#define DCPOMATIC_SIGNAL_MANAGER_H
+
+#include <boost/bind.hpp>
+#include <boost/asio.hpp>
+#include <boost/thread.hpp>
+
+class Signaller;
+
+/** A class to allow signals to be emitted from non-UI threads and handled
+ *  by a UI thread.
+ */
+class SignalManager : public boost::noncopyable
+{
+public:
+	/** Create a SignalManager.  Must be called from the UI thread */
+	SignalManager ()
+		: _work (_service)
+	{
+		_ui_thread = boost::this_thread::get_id ();
+	}
+
+	/* Do something next time the UI is idle */
+	template <typename T>
+	void when_idle (T f) {
+		_service.post (f);
+	}
+
+	/** Call this in the UI when it is idle */
+	size_t ui_idle () {
+		/* This executes any functors that have been post()ed to _service */
+		return _service.poll ();
+	}
+
+	/** This should wake the UI and make it call ui_idle() */
+	virtual void wake_ui () {
+		/* This is only a sensible implementation when there is no GUI */
+		ui_idle ();
+	}
+
+private:
+	/** Emit a signal from any thread whose handlers will be called in the UI
+	 *  thread.  Use something like:
+	 *
+	 *  ui_signaller->emit (boost::bind (boost::ref (SomeSignal), parameter));
+	 */
+	template <typename T>
+	void emit (T f) {
+		if (boost::this_thread::get_id() == _ui_thread) {
+			/* already in the UI thread */
+			f ();
+		} else {
+			/* non-UI thread; post to the service and wake up the UI */
+			_service.post (f);
+			wake_ui ();
+		}
+	}
+
+	friend class Signaller;
+	
+	/** A io_service which is used as the conduit for messages */
+	boost::asio::io_service _service;
+	/** Object required to keep io_service from stopping when it has nothing to do */
+	boost::asio::io_service::work _work;
+	/** The UI thread's ID */
+	boost::thread::id _ui_thread;
+};
+
+extern SignalManager* signal_manager;
+
+#endif