--- a/src/openttd.cpp	Sat Apr 19 08:34:03 2008 +0000
+++ b/src/openttd.cpp	Sat Apr 19 10:18:38 2008 +0000
@@ -92,6 +92,7 @@
 void MusicLoop();
 void ResetMusic();
 void ResetOldNames();
+void ProcessAsyncSaveFinish();
 
 extern void SetDifficultyLevel(int mode, GameOptions *gm_opt);
 extern Player* DoStartupNewPlayer(bool is_ai);
@@ -645,39 +646,6 @@
 	}
 }
 
-
-/** Mutex so that only one thread can communicate with the main program
- * at any given time */
-static ThreadMsg _message = MSG_OTTD_NO_MESSAGE;
-
-static inline void OTTD_ReleaseMutex() {_message = MSG_OTTD_NO_MESSAGE;}
-static inline ThreadMsg OTTD_PollThreadEvent() {return _message;}
-
-/** Called by running thread to execute some action in the main game.
- * It will stall as long as the mutex is not freed (handled) by the game */
-void OTTD_SendThreadMessage(ThreadMsg msg)
-{
-	if (_exit_game) return;
-	while (_message != MSG_OTTD_NO_MESSAGE) CSleep(10);
-
-	_message = msg;
-}
-
-
-/** Handle the user-messages sent to us
- * @param message message sent
- */
-static void ProcessSentMessage(ThreadMsg message)
-{
-	switch (message) {
-		case MSG_OTTD_SAVETHREAD_DONE:  SaveFileDone(); break;
-		case MSG_OTTD_SAVETHREAD_ERROR: SaveFileError(); break;
-		default: NOT_REACHED();
-	}
-
-	OTTD_ReleaseMutex(); // release mutex so that other threads, messages can be handled
-}
-
 static void ShowScreenshotResult(bool b)
 {
 	if (b) {
@@ -1095,9 +1063,7 @@
 
 void GameLoop()
 {
-	ThreadMsg message;
-
-	if ((message = OTTD_PollThreadEvent()) != 0) ProcessSentMessage(message);
+	ProcessAsyncSaveFinish();
 
 	/* autosave game? */
 	if (_do_autosave) {

--- a/src/openttd.h	Sat Apr 19 08:34:03 2008 +0000
+++ b/src/openttd.h	Sat Apr 19 10:18:38 2008 +0000
@@ -1,4 +1,5 @@
 /* $Id$ */
+
 /** @file openttd.h */
 
 #ifndef OPENTTD_H
@@ -108,17 +109,6 @@
 };
 extern byte _no_scroll;
 
-/** To have a concurrently running thread interface with the main program, use
- * the OTTD_SendThreadMessage() function. Actions to perform upon the message are handled
- * in the ProcessSentMessage() function */
-enum ThreadMsg {
-	MSG_OTTD_NO_MESSAGE,
-	MSG_OTTD_SAVETHREAD_DONE,
-	MSG_OTTD_SAVETHREAD_ERROR,
-};
-
-void OTTD_SendThreadMessage(ThreadMsg msg);
-
 extern byte _game_mode;
 extern bool _exit_game;
 extern int8 _pause_game;

--- a/src/saveload.cpp	Sat Apr 19 08:34:03 2008 +0000
+++ b/src/saveload.cpp	Sat Apr 19 10:18:38 2008 +0000
@@ -87,6 +87,32 @@
 	throw std::exception();
 }
 
+typedef void (*AsyncSaveFinishProc)();
+static AsyncSaveFinishProc _async_save_finish = NULL;
+
+/**
+ * Called by save thread to tell we finished saving.
+ */
+static void SetAsyncSaveFinish(AsyncSaveFinishProc proc)
+{
+	if (_exit_game) return;
+	while (_async_save_finish != NULL) CSleep(10);
+
+	_async_save_finish = proc;
+}
+
+/**
+ * Handle async save finishes.
+ */
+void ProcessAsyncSaveFinish()
+{
+	if (_async_save_finish == NULL) return;
+
+	_async_save_finish();
+
+	_async_save_finish = NULL;
+}
+
 /**
  * Fill the input buffer by reading from the file with the given reader
  */
@@ -1457,7 +1483,7 @@
 /** Update the gui accordingly when starting saving
  * and set locks on saveload. Also turn off fast-forward cause with that
  * saving takes Aaaaages */
-void SaveFileStart()
+static void SaveFileStart()
 {
 	_ts.ff_state = _fast_forward;
 	_fast_forward = 0;
@@ -1469,7 +1495,7 @@
 
 /** Update the gui accordingly when saving is done and release locks
  * on saveload */
-void SaveFileDone()
+static void SaveFileDone()
 {
 	_fast_forward = _ts.ff_state;
 	if (_cursor.sprite == SPR_CURSOR_ZZZ) SetMouseCursor(SPR_CURSOR_MOUSE, PAL_NONE);
@@ -1496,7 +1522,7 @@
 }
 
 /** Show a gui message when saving has failed */
-void SaveFileError()
+static void SaveFileError()
 {
 	SetDParamStr(0, GetSaveLoadErrorString());
 	ShowErrorMessage(STR_012D, STR_NULL, 0, 0);
@@ -1545,7 +1571,7 @@
 		GetSavegameFormat("memory")->uninit_write(); // clean the memorypool
 		fclose(_sl.fh);
 
-		if (threaded) OTTD_SendThreadMessage(MSG_OTTD_SAVETHREAD_DONE);
+		if (threaded) SetAsyncSaveFinish(SaveFileDone);
 
 		return SL_OK;
 	}
@@ -1557,7 +1583,7 @@
 		fprintf(stderr, GetSaveLoadErrorString());
 
 		if (threaded) {
-			OTTD_SendThreadMessage(MSG_OTTD_SAVETHREAD_ERROR);
+			SetAsyncSaveFinish(SaveFileError);
 		} else {
 			SaveFileError();
 		}

--- a/src/saveload.h	Sat Apr 19 08:34:03 2008 +0000
+++ b/src/saveload.h	Sat Apr 19 10:18:38 2008 +0000
@@ -319,7 +319,4 @@
 void SlObject(void *object, const SaveLoad *sld);
 bool SlObjectMember(void *object, const SaveLoad *sld);
 
-void SaveFileStart();
-void SaveFileDone();
-void SaveFileError();
 #endif /* SAVELOAD_H */