Added uiQueueMain() (basically g_idle_add()) and implemented it on all platforms except Haiku. A test to come. After this we can start rewriting the Go package ui at long last.

darwin/main.m

@@ -105,8 +105,18 @@ void uiMain(void)
 	[realNSApp() run];
 }
 
+// TODO make this delayed
 void uiQuit(void)
 {
 	canQuit = YES;
 	[realNSApp() terminate:realNSApp()];
 }
+
+// thanks to mikeash in irc.freenode.net/#macdev for suggesting the use of Grand Central Dispatch for this
+// TODO will dispatch_get_main_queue() break after _CFRunLoopSetCurrent()?
+void uiQueueMain(void (*f)(void *data), void *data)
+{
+	// dispatch_get_main_queue() is a serial queue so it will not execute multiple uiQueueMain() functions concurrently
+	// the signature of f matches dispatch_function_t
+	dispatch_async_f(dispatch_get_main_queue(), data, f);
+}

haiku/main.cpp

@@ -44,3 +44,8 @@ void uiQuit(void)
 	// TODO see window.cpp for why that alone won't work
 	app->Quit();
 }
+
+void uiQueueMain(void (*f)(void *data), void *data)
+{
+	// TODO
+}

ui.h

@@ -29,6 +29,9 @@ _UI_EXTERN void uiFreeInitError(const char *err);
 _UI_EXTERN void uiMain(void);
 _UI_EXTERN void uiQuit(void);
 
+// TODO write a test for this after adding multiline entries
+_UI_EXTERN void uiQueueMain(void (*f)(void *data), void *data);
+
 _UI_EXTERN void uiOnShouldQuit(int (*f)(void *data), void *data);
 
 _UI_EXTERN void uiFreeText(char *text);

unix/main.c

@@ -48,3 +48,28 @@ void uiQuit(void)
 {
 	gdk_threads_add_idle(quit, NULL);
 }
+
+struct queued {
+	void (*f)(void *);
+	void *data;
+};
+
+static gboolean doqueued(gpointer data)
+{
+	struct queued *q = (struct queued *) data;
+
+	(*(q->f))(q->data);
+	uiFree(q);
+	return FALSE;
+}
+
+// TODO document that the effect of calling this function after uiQuit() is called (either directly or via a nonzero return to uiShouldQuit()) is undefined
+void uiQueueMain(void (*f)(void *data), void *data)
+{
+	struct queued *q;
+
+	q = uiNew(struct queued);
+	q->f = f;
+	q->data = data;
+	gdk_threads_add_idle(doqueued, q);
+}

windows/main.c

@@ -41,3 +41,10 @@ void uiQuit(void)
 {
 	PostQuitMessage(0);
 }
+
+void uiQueueMain(void (*f)(void *data), void *data)
+{
+	if (PostMessageW(utilWindow, msgQueued, (WPARAM) f, (LPARAM) data) == 0)
+		// TODO make sure this is safe to call across threads
+		logLastError("error queueing function to run on main thread in uiQueueMain()");
+}

windows/uipriv_windows.h

@@ -13,6 +13,7 @@ enum {
 	msgNOTIFY,
 	msgHSCROLL,
 	msgConsoleEndSession,
+	msgQueued,
 };
 
 // init.c

windows/utilwin.c

@@ -18,6 +18,7 @@ HWND utilWindow;
 
 static LRESULT CALLBACK utilWindowWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 {
+	void (*qf)(void *);
 	LRESULT lResult;
 
 	if (handleParentMessages(hwnd, uMsg, wParam, lParam, &lResult) != FALSE)
@@ -41,6 +42,10 @@ static LRESULT CALLBACK utilWindowWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, L
 	case WM_WININICHANGE:
 		issueWM_WININICHANGE(wParam, lParam);
 		return 0;
+	case msgQueued:
+		qf = (void (*)(void *)) wParam;
+		(*qf)((void *) lParam);
+		return 0;
 	}
 	return DefWindowProcW(hwnd, uMsg, wParam, lParam);
 }