1 files changed, 64 insertions, 0 deletions
diff --git a/UICaboodle/UCYield.h b/UICaboodle/UCYield.h
new file mode 100644
index 0000000..dc75f8f
--- /dev/null
+++ b/UICaboodle/UCYield.h
@@ -0,0 +1,64 @@
+@interface NSObject (UICaboodle)
+- (id) yieldToSelector:(SEL)selector withObject:(id)object;
+- (id) yieldToSelector:(SEL)selector;
+@end
+
+@implementation NSObject (UICaboodle)
+
+- (void) doNothing {
+}
+
+- (void) _yieldToContext:(NSMutableArray *)context { _pooled
+    SEL selector(reinterpret_cast<SEL>([[context objectAtIndex:0] pointerValue]));
+    id object([[context objectAtIndex:1] nonretainedObjectValue]);
+    volatile bool &stopped(*reinterpret_cast<bool *>([[context objectAtIndex:2] pointerValue]));
+
+    /* XXX: deal with exceptions */
+    id value([self performSelector:selector withObject:object]);
+
+    NSMethodSignature *signature([self methodSignatureForSelector:selector]);
+    [context removeAllObjects];
+    if ([signature methodReturnLength] != 0 && value != nil)
+        [context addObject:value];
+
+    stopped = true;
+
+    [self
+        performSelectorOnMainThread:@selector(doNothing)
+        withObject:nil
+        waitUntilDone:NO
+    ];
+}
+
+- (id) yieldToSelector:(SEL)selector withObject:(id)object {
+    /*return [self performSelector:selector withObject:object];*/
+
+    volatile bool stopped(false);
+
+    NSMutableArray *context([NSMutableArray arrayWithObjects:
+        [NSValue valueWithPointer:selector],
+        [NSValue valueWithNonretainedObject:object],
+        [NSValue valueWithPointer:const_cast<bool *>(&stopped)],
+    nil]);
+
+    NSThread *thread([[[NSThread alloc]
+        initWithTarget:self
+        selector:@selector(_yieldToContext:)
+        object:context
+    ] autorelease]);
+
+    [thread start];
+
+    NSRunLoop *loop([NSRunLoop currentRunLoop]);
+    NSDate *future([NSDate distantFuture]);
+
+    while (!stopped && [loop runMode:NSDefaultRunLoopMode beforeDate:future]);
+
+    return [context count] == 0 ? nil : [context objectAtIndex:0];
+}
+
+- (id) yieldToSelector:(SEL)selector {
+    return [self yieldToSelector:selector withObject:nil];
+}
+
+@end