1/*
2 * Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1.  Redistributions of source code must retain the above copyright
9 *     notice, this list of conditions and the following disclaimer.
10 * 2.  Redistributions in binary form must reproduce the above copyright
11 *     notice, this list of conditions and the following disclaimer in the
12 *     documentation and/or other materials provided with the distribution.
13 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14 *     its contributors may be used to endorse or promote products derived
15 *     from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#import "config.h"
30#import "MainThread.h"
31
32#import <CoreFoundation/CoreFoundation.h>
33#import <Foundation/NSThread.h>
34#import <stdio.h>
35#import <wtf/Assertions.h>
36#import <wtf/Threading.h>
37
38@interface WTFMainThreadCaller : NSObject {
39}
40- (void)call;
41@end
42
43@implementation WTFMainThreadCaller
44
45- (void)call
46{
47    WTF::dispatchFunctionsFromMainThread();
48}
49
50@end // implementation WTFMainThreadCaller
51
52namespace WTF {
53
54static WTFMainThreadCaller* staticMainThreadCaller;
55static bool isTimerPosted; // This is only accessed on the 'main' thread.
56static bool mainThreadEstablishedAsPthreadMain;
57static pthread_t mainThreadPthread;
58static NSThread* mainThreadNSThread;
59
60void initializeMainThreadPlatform()
61{
62#if !defined(BUILDING_ON_TIGER)
63    ASSERT(!staticMainThreadCaller);
64    staticMainThreadCaller = [[WTFMainThreadCaller alloc] init];
65
66    mainThreadEstablishedAsPthreadMain = false;
67    mainThreadPthread = pthread_self();
68    mainThreadNSThread = [[NSThread currentThread] retain];
69#else
70    ASSERT_NOT_REACHED();
71#endif
72}
73
74void initializeMainThreadToProcessMainThreadPlatform()
75{
76    if (!pthread_main_np())
77        NSLog(@"WebKit Threading Violation - initial use of WebKit from a secondary thread.");
78
79    ASSERT(!staticMainThreadCaller);
80    staticMainThreadCaller = [[WTFMainThreadCaller alloc] init];
81
82    mainThreadEstablishedAsPthreadMain = true;
83    mainThreadPthread = 0;
84    mainThreadNSThread = nil;
85}
86
87static void timerFired(CFRunLoopTimerRef timer, void*)
88{
89    CFRelease(timer);
90    isTimerPosted = false;
91    WTF::dispatchFunctionsFromMainThread();
92}
93
94static void postTimer()
95{
96    ASSERT(isMainThread());
97
98    if (isTimerPosted)
99        return;
100
101    isTimerPosted = true;
102    CFRunLoopAddTimer(CFRunLoopGetCurrent(), CFRunLoopTimerCreate(0, 0, 0, 0, 0, timerFired, 0), kCFRunLoopCommonModes);
103}
104
105void scheduleDispatchFunctionsOnMainThread()
106{
107    ASSERT(staticMainThreadCaller);
108
109    if (isMainThread()) {
110        postTimer();
111        return;
112    }
113
114    if (mainThreadEstablishedAsPthreadMain) {
115        ASSERT(!mainThreadNSThread);
116        [staticMainThreadCaller performSelectorOnMainThread:@selector(call) withObject:nil waitUntilDone:NO];
117        return;
118    }
119
120#if !defined(BUILDING_ON_TIGER)
121    ASSERT(mainThreadNSThread);
122    [staticMainThreadCaller performSelector:@selector(call) onThread:mainThreadNSThread withObject:nil waitUntilDone:NO];
123#else
124    ASSERT_NOT_REACHED();
125#endif
126}
127
128bool isMainThread()
129{
130    if (mainThreadEstablishedAsPthreadMain) {
131        ASSERT(!mainThreadPthread);
132        return pthread_main_np();
133    }
134
135#if !defined(BUILDING_ON_TIGER)
136    ASSERT(mainThreadPthread);
137    return pthread_equal(pthread_self(), mainThreadPthread);
138#else
139    ASSERT_NOT_REACHED();
140    return false;
141#endif
142}
143
144} // namespace WTF
145