// // $Id$ // // SPMainThreadTrampoline.m // sequel-pro // // Created by Rowan Beentje on 20/03/2010. // Copyright 2010 Rowan Beentje. All rights reserved. // // This program is free software; you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation; either version 2 of the License, or // (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA // // More info at <http://code.google.com/p/sequel-pro/> #import "SPMainThreadTrampoline.h" @implementation NSObject (SPMainThreadTrampoline) /** * Provide a category on all NSObjects to return a trampoline for that * object on the main thread. * This cannot be retained or released. */ - (id) onMainThread { // Return an autoreleased trampoline object return [[[SPMainThreadTrampoline alloc] initWithObject:self] autorelease]; } /** * Provide a retained version of the category */ - (id) retainedOnMainThread { return [[SPMainThreadTrampoline alloc] initWithObject:self]; } @end @implementation SPMainThreadTrampoline /** * The master initiliasation - the category implementation calls this * with the requested object. */ - (id) initWithObject:(id)theObject { if ((self = [super init])) { trampolineObject = theObject; } return self; } /** * Delegate unrecognised methods to the trampolined objects, thanks to the magic * of NSInvocation (see forwardInvocation: docs for background). Must be paired * with methodSignationForSelector:. */ - (void) forwardInvocation:(NSInvocation *)theInvocation { SEL theSelector = [theInvocation selector]; if (![trampolineObject respondsToSelector:theSelector]) [self doesNotRecognizeSelector:theSelector]; // Retain the arguments and object for the call for safety [theInvocation retainArguments]; [trampolineObject retain]; [theInvocation performSelectorOnMainThread:@selector(invokeWithTarget:) withObject:trampolineObject waitUntilDone:YES]; [trampolineObject release]; } /** * Return the correct method signatures for the trampolined object if * NSObject doesn't implement the requested methods. */ - (NSMethodSignature *) methodSignatureForSelector:(SEL)theSelector { NSMethodSignature *defaultSignature = [super methodSignatureForSelector:theSelector]; if (defaultSignature) return defaultSignature; return [trampolineObject methodSignatureForSelector:theSelector]; } /** * Override the default repondsToSelector:, returning true if either NSObject * or the trampolined object supports the selector. */ - (BOOL) respondsToSelector:(SEL)theSelector { return ([super respondsToSelector:theSelector] || [trampolineObject respondsToSelector:theSelector]); } /** * Override the default performSelector:, again either using NSObject defaults * or performing the selector on the trampolined object. * Note that the return value from the trampolined object is not preserved in this case. */ - (id) performSelector:(SEL)theSelector { if ([super respondsToSelector:theSelector]) return [super performSelector:theSelector]; if (![trampolineObject respondsToSelector:theSelector]) [self doesNotRecognizeSelector:theSelector]; // Retain the object while performing calls on it [trampolineObject retain]; [trampolineObject performSelectorOnMainThread:theSelector withObject:nil waitUntilDone:YES]; [trampolineObject release]; return nil; } /** * Override the default performSelector:withObject: - see performSelector: * Note that the return value from the trampolined object is not preserved in this case. */ - (id) performSelector:(SEL)theSelector withObject:(id)theObject { if ([super respondsToSelector:theSelector]) return [super performSelector:theSelector withObject:theObject]; if (![trampolineObject respondsToSelector:theSelector]) [self doesNotRecognizeSelector:theSelector]; // Retain the trampolined object, and the argument object, while performing calls [trampolineObject retain]; [theObject retain]; [trampolineObject performSelectorOnMainThread:theSelector withObject:theObject waitUntilDone:YES]; [theObject release]; [trampolineObject release]; return nil; } /** * If the trampoline is sent the onMainThread category, just return the trampoline directly. */ - (id) onMainThread { return self; } @end