/*

 * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1.  Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer.

 * 2.  Redistributions in binary form must reproduce the above copyright

 *     notice, this list of conditions and the following disclaimer in the

 *     documentation and/or other materials provided with the distribution.

 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of

 *     its contributors may be used to endorse or promote products derived

 *     from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY

 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#import "WebNSObjectExtras.h"

#import <wtf/Assertions.h>

@interface WebMainThreadInvoker : NSProxy

{

    id target;

    id exception;

}

@end

static bool returnTypeIsObject(NSInvocation *invocation)

{

    // Could use either _C_ID or NSObjCObjectType, but it seems that neither is

    // both available and non-deprecated on all versions of Mac OS X we support.

    return strchr([[invocation methodSignature] methodReturnType], '@');

}

@implementation WebMainThreadInvoker

- (id)initWithTarget:(id)passedTarget

{

    target = passedTarget;

    return self;

}

- (void)forwardInvocation:(NSInvocation *)invocation

{

    [invocation setTarget:target];

    [invocation performSelectorOnMainThread:@selector(_webkit_invokeAndHandleException:) withObject:self waitUntilDone:YES];

    if (exception) {

        id exceptionToThrow = [exception autorelease];

        exception = nil;

        @throw exceptionToThrow;

    } else if (returnTypeIsObject(invocation)) {

        // _webkit_invokeAndHandleException retained the return value on the main thread.

        // Now autorelease it on the calling thread.

        id returnValue;

        [invocation getReturnValue:&returnValue];

        [returnValue autorelease];

    }

}

- (NSMethodSignature *)methodSignatureForSelector:(SEL)selector

{

    return [target methodSignatureForSelector:selector];

}

- (void)handleException:(id)passedException

{

    ASSERT(!exception);

    exception = [passedException retain];

}

@end

@implementation NSInvocation (WebMainThreadInvoker)

- (void)_webkit_invokeAndHandleException:(WebMainThreadInvoker *)exceptionHandler

{

    @try {

        [self invoke];

    } @catch (id exception) {

        [exceptionHandler handleException:exception];

        return;

    }

    if (returnTypeIsObject(self)) {

        // Retain the return value on the main thread.

        // -[WebMainThreadInvoker forwardInvocation:] will autorelease it on the calling thread.

        id value;

        [self getReturnValue:&value];

        [value retain];

    }

}

@end

@implementation NSObject (WebNSObjectExtras)

+ (id)_webkit_invokeOnMainThread

{

    return [[[WebMainThreadInvoker alloc] initWithTarget:self] autorelease];

}

- (id)_webkit_invokeOnMainThread

{

    return [[[WebMainThreadInvoker alloc] initWithTarget:self] autorelease];

}

@end