1/*
2 * Copyright (C) 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#ifndef LabelScope_h
30#define LabelScope_h
31
32#include <wtf/PassRefPtr.h>
33#include "Label.h"
34
35namespace JSC {
36
37    class Identifier;
38
39    class LabelScope {
40    public:
41        enum Type { Loop, Switch, NamedLabel };
42
43        LabelScope(Type type, const Identifier* name, int scopeDepth, PassRefPtr<Label> breakTarget, PassRefPtr<Label> continueTarget)
44            : m_refCount(0)
45            , m_type(type)
46            , m_name(name)
47            , m_scopeDepth(scopeDepth)
48            , m_breakTarget(breakTarget)
49            , m_continueTarget(continueTarget)
50        {
51        }
52        int refCount() const { return m_refCount; }
53
54        Label* breakTarget() const { return m_breakTarget.get(); }
55        Label* continueTarget() const { return m_continueTarget.get(); }
56
57        Type type() const { return m_type; }
58        const Identifier* name() const { return m_name; }
59        int scopeDepth() const { return m_scopeDepth; }
60
61    private:
62        friend class LabelScopePtr;
63
64        void ref() { ++m_refCount; }
65        void deref()
66        {
67            --m_refCount;
68            ASSERT(m_refCount >= 0);
69        }
70
71        int m_refCount;
72        Type m_type;
73        const Identifier* m_name;
74        int m_scopeDepth;
75        RefPtr<Label> m_breakTarget;
76        RefPtr<Label> m_continueTarget;
77    };
78
79    typedef Vector<LabelScope, 8> LabelScopeStore;
80
81    class LabelScopePtr {
82    public:
83        LabelScopePtr()
84            : m_owner(0)
85            , m_index(0)
86        {
87        }
88        LabelScopePtr(LabelScopeStore* owner, size_t index)
89            : m_owner(owner)
90            , m_index(index)
91        {
92            m_owner->at(index).ref();
93        }
94
95        LabelScopePtr(const LabelScopePtr& other)
96            : m_owner(other.m_owner)
97            , m_index(other.m_index)
98        {
99            if (m_owner)
100                m_owner->at(m_index).ref();
101        }
102
103        const LabelScopePtr& operator=(const LabelScopePtr& other)
104        {
105            if (other.m_owner)
106                other.m_owner->at(other.m_index).ref();
107            if (m_owner)
108                m_owner->at(m_index).deref();
109            m_owner = other.m_owner;
110            m_index = other.m_index;
111            return *this;
112        }
113
114        ~LabelScopePtr()
115        {
116            if (m_owner)
117                m_owner->at(m_index).deref();
118        }
119
120        LabelScope& operator*() { ASSERT(m_owner); return m_owner->at(m_index); }
121        LabelScope* operator->() { ASSERT(m_owner); return &m_owner->at(m_index); }
122        const LabelScope& operator*() const { ASSERT(m_owner); return m_owner->at(m_index); }
123        const LabelScope* operator->() const { ASSERT(m_owner); return &m_owner->at(m_index); }
124
125    private:
126        LabelScopeStore* m_owner;
127        size_t m_index;
128    };
129
130} // namespace JSC
131
132#endif // LabelScope_h
133