Fix crashes on x-thread signal emission.

[dcpomatic.git] / src / lib / ui_signaller.h

diff --git a/src/lib/ui_signaller.h b/src/lib/ui_signaller.h
index ee4d230d407e566114ae57b491700196c19d21c5..9d4495cd18921822b2fcfa02836a3c916f2cfedd 100644 (file)
--- a/src/lib/ui_signaller.h
+++ b/src/lib/ui_signaller.h
@@ -24,6 +24,8 @@
 #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.
  */
@@ -37,23 +39,6 @@ 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 ();
-               }
-       }
-
        /* Do something next time the UI is idle */
        template <typename T>
        void when_idle (T f) {
@@ -73,6 +58,25 @@ public:
        }
 
 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 */