bytecompiler/LabelScope.h

   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 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
  35 namespace 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         bool operator!() const { return !m_owner; }
 121
 122         LabelScope& operator*() { ASSERT(m_owner); return m_owner->at(m_index); }
 123         LabelScope* operator->() { ASSERT(m_owner); return &m_owner->at(m_index); }
 124         const LabelScope& operator*() const { ASSERT(m_owner); return m_owner->at(m_index); }
 125         const LabelScope* operator->() const { ASSERT(m_owner); return &m_owner->at(m_index); }
 126
 127         static LabelScopePtr null() { return LabelScopePtr(); }
 128
 129     private:
 130         LabelScopeStore* m_owner;
 131         size_t m_index;
 132     };
 133
 134 } // namespace JSC
 135
 136 #endif // LabelScope_h