1/*
2 * Copyright (C) 2012 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 WebScopedMicrotaskSuppression_h
32#define WebScopedMicrotaskSuppression_h
33
34#include "../platform/WebPrivateOwnPtr.h"
35
36namespace blink {
37
38// This class wraps V8RecursionScope::BypassMicrotaskCheckpoint. Please
39// see V8RecursionScope.h for full usage. Short story: Embedder calls into
40// script contexts which also host page script must do one of two things:
41//
42//   1. If the call may cause any page/author script to run, it must be
43//      captured for pre/post work (e.g. inspector instrumentation/microtask
44//      delivery) and thus be invoked through WebFrame (e.g. executeScript*,
45//      callFunction*).
46//   2. If the call will not cause any page/author script to run, the call
47//      should be made directly via the v8 context, but the callsite must be
48//      accompanied by a stack allocated WebScopedMicrotaskSuppression, e.g.:
49//
50//        ...
51//        {
52//            blink::WebScopedMicrotaskSuppression suppression;
53//            func->Call(global, argv, args);
54//        }
55//        ...
56//
57class WebScopedMicrotaskSuppression {
58public:
59    WebScopedMicrotaskSuppression() { initialize(); }
60    ~WebScopedMicrotaskSuppression() { reset(); }
61
62private:
63    BLINK_EXPORT void initialize();
64    BLINK_EXPORT void reset();
65
66    // Always declare this data member. When assertions are on in
67    // Release builds of Blink, this header may be included from
68    // Chromium with different preprocessor options than used when
69    // building Blink itself.
70    class Impl;
71    WebPrivateOwnPtr<Impl> m_impl;
72};
73
74} // WebKit
75
76#endif
77