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[cydia.git] / Menes / yieldToSelector.mm

/* Cydia - iPhone UIKit Front-End for Debian APT
 * Copyright (C) 2008-2011  Jay Freeman (saurik)
*/

/* Modified BSD License {{{ */
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 *
 * 1. Redistributions of source code must retain the
 *    above copyright notice, this list of conditions
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/* }}} */

#include "Menes/yieldToSelector.h"

@implementation NSObject (MenesYieldToSelector)

- (void) doNothing {
}

- (void) _yieldToContext:(NSMutableArray *)context {
    NSAutoreleasePool *pool([[NSAutoreleasePool alloc] init]);

    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
    ];

    [pool release];
}

- (id) yieldToSelector:(SEL)selector withObject:(id)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]);
    NSString *mode([loop currentMode] ?: NSDefaultRunLoopMode);

    while (!stopped && [loop runMode:mode beforeDate:future]);

    return [context count] == 0 ? nil : [context objectAtIndex:0];
}

- (id) yieldToSelector:(SEL)selector {
    return [self yieldToSelector:selector withObject:nil];
}

@end