Started to implement proper destruction logic for Mac OS X controls.

init_darwin.m

@@ -40,6 +40,11 @@
 
 @end
 
+// we are not in control of the actual lifetimes and refcounts of NSViews (see http://stackoverflow.com/a/29523141/3408572)
+// when we're done with a view, it'll be added as a subview of this one, and this one will be released on application shutdown
+// we need this separate view because it's possible for controls to have no parent but still be alive
+NSView *deletedControlsView;
+
 uiInitOptions options;
 
 const char *uiInit(uiInitOptions *o)
@@ -50,6 +55,10 @@ const char *uiInit(uiInitOptions *o)
 	// see https://github.com/andlabs/ui/issues/6
 	[NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
 	[NSApp setDelegate:[uiAppDelegate new]];
+
+	// we can use a stock NSView for this
+	deletedControlsView = [[NSView alloc] initWithFrame:NSZeroRect];
+
 	return NULL;
 }
 

newcontrol_darwin.m

@@ -10,12 +10,11 @@ struct singleView {
 	uintptr_t parent;
 };
 
-// TODO this will need to change if we want to provide removal
 static void singleDestroy(uiControl *c)
 {
 	singleView *s = (singleView *) (c->internal);
 
-	[s->view removeFromSuperview];
+	[deletedControlsView addSubview:s->immediate];
 }
 
 static uintptr_t singleHandle(uiControl *c)
@@ -99,6 +98,9 @@ uiControl *uiDarwinNewControl(Class class, BOOL inScrollView, BOOL scrollViewHas
 		s->immediate = (NSView *) (s->scrollView);
 	}
 
+	// and keep a reference to s->immediate for when we remove the control from its parent
+	[s->immediate retain];
+
 	c = uiNew(uiControl);
 	c->internal = s;
 	c->destroy = singleDestroy;
@@ -115,7 +117,8 @@ BOOL uiDarwinControlFreeWhenAppropriate(uiControl *c, NSView *newSuperview)
 {
 	singleView *s = (singleView *) (c->internal);
 
-	if (newSuperview == nil) {
+	if (newSuperview == deletedControlsView) {
+		[s->immediate release];		// we don't need the reference anymore
 		uiFree(s);
 		uiFree(c);
 		return YES;

uipriv_darwin.h

@@ -24,6 +24,9 @@
 		fprintf(stderr, "%p free\n", self); \
 }
 
+// init_darwin.m
+extern NSView *deletedControlsView;
+
 // util_darwin.m
 extern void setStandardControlFont(NSControl *);
 extern void disableAutocorrect(NSTextView *);