1/*
2 * Copyright (C) 2014 Google 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 are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#ifndef MessageLoopInterruptor_h
32#define MessageLoopInterruptor_h
33
34#include "platform/heap/ThreadState.h"
35#include "public/platform/WebThread.h"
36
37namespace blink {
38
39class MessageLoopInterruptor : public ThreadState::Interruptor {
40public:
41    explicit MessageLoopInterruptor(blink::WebThread* thread) : m_thread(thread) { }
42
43    virtual void requestInterrupt() OVERRIDE
44    {
45        // GCTask has an empty run() method. Its only purpose is to guarantee
46        // that MessageLoop will have a task to process which will result
47        // in PendingGCRunner::didProcessTask being executed.
48        m_thread->postTask(new GCTask);
49    }
50
51    virtual void clearInterrupt() OVERRIDE { }
52
53private:
54    class GCTask : public blink::WebThread::Task {
55    public:
56        virtual ~GCTask() { }
57
58        virtual void run() OVERRIDE
59        {
60            // Don't do anything here because we don't know if this is
61            // a nested event loop or not. PendingGCRunner::didProcessTask
62            // will enter correct safepoint for us.
63            // We are not calling onInterrupted() because that always
64            // conservatively enters safepoint with pointers on stack.
65        }
66    };
67
68    blink::WebThread* m_thread;
69};
70
71}
72
73#endif
74