From d29e1b8710ffe259ad7b532fb76056c52e2061ae Mon Sep 17 00:00:00 2001
From: Pietro Gagliardi <pietro10@mac.com>
Date: Wed, 5 Mar 2014 20:09:15 -0500
Subject: [PATCH] Have ui.Go() return on main() return on Mac OS X.

---
 bleh_darwin.m    | 29 +++++++++++++++++++++++++++++
 objc_darwin.h    |  4 ++++
 uitask_darwin.go | 17 ++++++++++++++++-
 3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/bleh_darwin.m b/bleh_darwin.m
index ca9c91a..08b02bb 100644
--- a/bleh_darwin.m
+++ b/bleh_darwin.m
@@ -7,6 +7,7 @@ The main culprits are:
 - data types listed as being defined in nonexistent headers
 - 32-bit/64-bit type differences that are more than just a different typedef
 - wrong documentation
+though this is not always the case.
 
 Go wrapper functions (bleh_darwin.go) call these directly and take care of stdint.h -> Go type conversions.
 */
@@ -17,6 +18,7 @@ Go wrapper functions (bleh_darwin.go) call these directly and take care of stdin
 
 #include <Foundation/NSGeometry.h>
 #include <AppKit/NSKeyValueBinding.h>
+#include <AppKit/NSEvent.h>
 
 /* exception to the above: cgo doesn't like Nil and delegate_darwin.go has //export so I can't have this there */
 Class NilClass = Nil;
@@ -155,3 +157,30 @@ uintptr_t *NSIndexSetEntries(id indexset, uintptr_t count)
 	free(nsuints);
 	return ret;
 }
+
+/*
+See uitask_darwin.go: we need to synthesize a NSEvent so -[NSApplication stop:] will work. We cannot simply init the default NSEvent though (it throws an exception) so we must do it "the right way". This involves a very convoluted initializer; we'll just do it here to keep things clean on the Go side (this will only be run once anyway, on program exit).
+*/
+
+static id c_NSEvent;
+static SEL s_newEvent;
+static BOOL newEvent_init = NO;
+
+id makeDummyEvent()
+{
+	if (newEvent_init == NO) {
+		c_NSEvent = objc_getClass("NSEvent");
+		s_newEvent = sel_getUid("otherEventWithType:location:modifierFlags:timestamp:windowNumber:context:subtype:data1:data2:");
+		newEvent_init = YES;
+	}
+	return objc_msgSend(c_NSEvent, s_newEvent,
+		(NSUInteger) NSApplicationDefined,			/* otherEventWithType: */
+		NSMakePoint(0, 0),						/* location: */
+		(NSUInteger) 0,							/* modifierFlags: */
+		(double) 0,							/* timestamp: */
+		(NSInteger) 0,							/* windowNumber: */
+		nil,									/* context: */
+		(short) 0,								/* subtype: */
+		(NSInteger) 0,							/* data1: */
+		(NSInteger) 0);							/* data2: */
+}
diff --git a/objc_darwin.h b/objc_darwin.h
index e2d9d92..f73bc2b 100644
--- a/objc_darwin.h
+++ b/objc_darwin.h
@@ -89,6 +89,7 @@ m2(id_id, id, id)
 extern id _objc_msgSend_rect_bool(id obj, SEL sel, int64_t x, int64_t y, int64_t w, int64_t h, BOOL b);
 extern id objc_msgSend_id_int(id obj, SEL sel, id a, intptr_t b);
 extern id objc_msgSend_id_uint(id obj, SEL sel, id a, uintptr_t b);
+m2(id_bool, id, BOOL)
 
 m3(id_id_id, id, id, id)
 m3(sel_id_bool, SEL, id, BOOL)
@@ -100,4 +101,7 @@ m4(id_id_id_id, id, id, id, id)
 /* for listbox_darwin.go */
 extern uintptr_t *NSIndexSetEntries(id, uintptr_t);
 
+/* for uitask_darwin.go */
+extern id makeDummyEvent();
+
 #endif
diff --git a/uitask_darwin.go b/uitask_darwin.go
index 8a77dfa..6acf080 100644
--- a/uitask_darwin.go
+++ b/uitask_darwin.go
@@ -20,6 +20,8 @@ var (
 	_valueWithPointer = sel_getUid("valueWithPointer:")
 	_performSelectorOnMainThread =
 		sel_getUid("performSelectorOnMainThread:withObject:waitUntilDone:")
+	_stop = sel_getUid("stop:")
+	_postEventAtStart = sel_getUid("postEvent:atStart:")
 	_pointerValue = sel_getUid("pointerValue")
 	_run = sel_getUid("run")
 )
@@ -51,7 +53,20 @@ func ui(main func()) error {
 		}
 	}()
 
-	go main()
+	go func() {
+		main()
+		uitask <- func() {
+			// -[NSApplication stop:] stops the event loop; it won't do a clean termination, but we're not too concerned with that (at least not on the other platforms either so)
+			// we can't call -[NSApplication terminate:] because that will just quit the program, ensuring we never leave ui.Go()
+			C.objc_msgSend_id(NSApp, _stop, NSApp)
+			// simply calling -[NSApplication stop:] is not good enough, as the stop flag is only checked when an event comes in
+			// we have to create a "proper" event; a blank event will just throw an exception
+			C.objc_msgSend_id_bool(NSApp,
+				_postEventAtStart,
+				C.makeDummyEvent(),
+				C.BOOL(C.NO))			// not at start, just in case there are other events pending (TODO is this correct?)
+		}
+	}()
 
 	C.objc_msgSend_noargs(NSApp, _run)
 	return nil