1/*
2 * Copyright (C) 2017-2019 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 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include <wtf/ForbidHeapAllocation.h>
29#include <wtf/Noncopyable.h>
30
31namespace JSC {
32
33template<class T>
34class DisallowScope {
35 WTF_MAKE_NONCOPYABLE(DisallowScope);
36 WTF_FORBID_HEAP_ALLOCATION;
37public:
38#ifdef NDEBUG
39
40 ALWAYS_INLINE DisallowScope(bool = false) { }
41 ALWAYS_INLINE ~DisallowScope() { }
42 ALWAYS_INLINE static bool isInEffectOnCurrentThread() { return false; }
43 ALWAYS_INLINE void enable() { }
44
45#else // not NDEBUG
46
47 DisallowScope(bool enabled = true)
48 {
49 m_isEnabled = enabled;
50 if (m_isEnabled)
51 enterScope();
52 }
53
54 ~DisallowScope()
55 {
56 if (m_isEnabled)
57 exitScope();
58 }
59
60 static bool isInEffectOnCurrentThread()
61 {
62 return !!T::scopeReentryCount();
63 }
64
65 void enable()
66 {
67 m_isEnabled = true;
68 enterScope();
69 }
70
71 void disable()
72 {
73 m_isEnabled = false;
74 exitScope();
75 }
76
77private:
78 void enterScope()
79 {
80 auto count = T::scopeReentryCount();
81 T::setScopeReentryCount(++count);
82 }
83
84 void exitScope()
85 {
86 auto count = T::scopeReentryCount();
87 ASSERT(count);
88 T::setScopeReentryCount(--count);
89 }
90
91 bool m_isEnabled;
92#endif // NDEBUG
93};
94
95} // namespace JSC
96