Add some comments.

2 files changed, 17 insertions, 1 deletions

diff --git a/src/lib/ui_signaller.cc b/src/lib/ui_signaller.cc
index 4f39a6187..4cb34da51 100644
--- a/src/lib/ui_signaller.cc
+++ b/src/lib/ui_signaller.cc
@@ -19,5 +19,6 @@
 
 #include "ui_signaller.h"
 
+/** Global UISignaller instance */
 UISignaller* ui_signaller = 0;
 
diff --git a/src/lib/ui_signaller.h b/src/lib/ui_signaller.h
index 9de1b736d..221bcbe95 100644
--- a/src/lib/ui_signaller.h
+++ b/src/lib/ui_signaller.h
@@ -24,6 +24,9 @@
 #include <boost/asio.hpp>
 #include <boost/thread.hpp>
 
+/** A class to allow signals to be emitted from non-UI threads and handled
+ *  by a UI thread.
+ */
 class UISignaller
 {
 public:
@@ -33,26 +36,38 @@ public:
 	{
 		_ui_thread = boost::this_thread::get_id ();
 	}
-	
+
+	/** 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 ();
 		}
 	}
 
+	/** Call this in the UI when it is idle */
 	void ui_idle () {
 		_service.poll ();
 	}
 
+	/** This should wake the UI and make it call ui_idle() */
 	virtual void wake_ui () = 0;
 
 private:
+	/** 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;
 };