runtime/PropertySlot.h

   1 /*
   2  *  Copyright (C) 2005, 2007, 2008 Apple Inc. All rights reserved.
   3  *
   4  *  This library is free software; you can redistribute it and/or
   5  *  modify it under the terms of the GNU Library General Public
   6  *  License as published by the Free Software Foundation; either
   7  *  version 2 of the License, or (at your option) any later version.
   8  *
   9  *  This library is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *  Library General Public License for more details.
  13  *
  14  *  You should have received a copy of the GNU Library General Public License
  15  *  along with this library; see the file COPYING.LIB.  If not, write to
  16  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  *  Boston, MA 02110-1301, USA.
  18  *
  19  */
  20
  21 #ifndef PropertySlot_h
  22 #define PropertySlot_h
  23
  24 #include "Identifier.h"
  25 #include "JSValue.h"
  26 #include "JSImmediate.h"
  27 #include "Register.h"
  28 #include <wtf/Assertions.h>
  29 #include <wtf/NotFound.h>
  30
  31 namespace JSC {
  32
  33     class ExecState;
  34     class JSObject;
  35
  36 #define JSC_VALUE_SLOT_MARKER 0
  37 #define JSC_REGISTER_SLOT_MARKER reinterpret_cast<GetValueFunc>(1)
  38
  39     class PropertySlot {
  40     public:
  41         PropertySlot()
  42             : m_offset(WTF::notFound)
  43         {
  44             clearBase();
  45             clearValue();
  46         }
  47
  48         explicit PropertySlot(const JSValuePtr base)
  49             : m_slotBase(base)
  50             , m_offset(WTF::notFound)
  51         {
  52             clearValue();
  53         }
  54
  55         typedef JSValuePtr (*GetValueFunc)(ExecState*, const Identifier&, const PropertySlot&);
  56
  57         JSValuePtr getValue(ExecState* exec, const Identifier& propertyName) const
  58         {
  59             if (m_getValue == JSC_VALUE_SLOT_MARKER)
  60                 return *m_data.valueSlot;
  61             if (m_getValue == JSC_REGISTER_SLOT_MARKER)
  62                 return (*m_data.registerSlot).jsValue(exec);
  63             return m_getValue(exec, propertyName, *this);
  64         }
  65
  66         JSValuePtr getValue(ExecState* exec, unsigned propertyName) const
  67         {
  68             if (m_getValue == JSC_VALUE_SLOT_MARKER)
  69                 return *m_data.valueSlot;
  70             if (m_getValue == JSC_REGISTER_SLOT_MARKER)
  71                 return (*m_data.registerSlot).jsValue(exec);
  72             return m_getValue(exec, Identifier::from(exec, propertyName), *this);
  73         }
  74
  75         bool isCacheable() const { return m_offset != WTF::notFound; }
  76         size_t cachedOffset() const
  77         {
  78             ASSERT(isCacheable());
  79             return m_offset;
  80         }
  81
  82         void putValue(JSValuePtr value)
  83         {
  84             if (m_getValue == JSC_VALUE_SLOT_MARKER) {
  85                 *m_data.valueSlot = value;
  86                 return;
  87             }
  88             ASSERT(m_getValue == JSC_REGISTER_SLOT_MARKER);
  89             *m_data.registerSlot = JSValuePtr(value);
  90         }
  91
  92         void setValueSlot(JSValuePtr* valueSlot)
  93         {
  94             ASSERT(valueSlot);
  95             m_getValue = JSC_VALUE_SLOT_MARKER;
  96             clearBase();
  97             m_data.valueSlot = valueSlot;
  98         }
  99
 100         void setValueSlot(JSValuePtr slotBase, JSValuePtr* valueSlot)
 101         {
 102             ASSERT(valueSlot);
 103             m_getValue = JSC_VALUE_SLOT_MARKER;
 104             m_slotBase = slotBase;
 105             m_data.valueSlot = valueSlot;
 106         }
 107
 108         void setValueSlot(JSValuePtr slotBase, JSValuePtr* valueSlot, size_t offset)
 109         {
 110             ASSERT(valueSlot);
 111             m_getValue = JSC_VALUE_SLOT_MARKER;
 112             m_slotBase = slotBase;
 113             m_data.valueSlot = valueSlot;
 114             m_offset = offset;
 115         }
 116
 117         void setValue(JSValuePtr value)
 118         {
 119             ASSERT(value);
 120             m_getValue = JSC_VALUE_SLOT_MARKER;
 121             clearBase();
 122             m_value = value;
 123             m_data.valueSlot = &m_value;
 124         }
 125
 126         void setRegisterSlot(Register* registerSlot)
 127         {
 128             ASSERT(registerSlot);
 129             m_getValue = JSC_REGISTER_SLOT_MARKER;
 130             clearBase();
 131             m_data.registerSlot = registerSlot;
 132         }
 133
 134         void setCustom(JSValuePtr slotBase, GetValueFunc getValue)
 135         {
 136             ASSERT(slotBase);
 137             ASSERT(getValue);
 138             m_getValue = getValue;
 139             m_slotBase = slotBase;
 140         }
 141
 142         void setCustomIndex(JSValuePtr slotBase, unsigned index, GetValueFunc getValue)
 143         {
 144             ASSERT(slotBase);
 145             ASSERT(getValue);
 146             m_getValue = getValue;
 147             m_slotBase = slotBase;
 148             m_data.index = index;
 149         }
 150
 151         void setGetterSlot(JSObject* getterFunc)
 152         {
 153             ASSERT(getterFunc);
 154             m_getValue = functionGetter;
 155             m_data.getterFunc = getterFunc;
 156         }
 157
 158         void setUndefined()
 159         {
 160             clearBase();
 161             setValue(jsUndefined());
 162         }
 163
 164         JSValuePtr slotBase() const
 165         {
 166             ASSERT(m_slotBase);
 167             return m_slotBase;
 168         }
 169
 170         void setBase(JSValuePtr base)
 171         {
 172             ASSERT(m_slotBase);
 173             ASSERT(base);
 174             m_slotBase = base;
 175         }
 176
 177         void clearBase()
 178         {
 179 #ifndef NDEBUG
 180             m_slotBase = noValue();
 181 #endif
 182         }
 183
 184         void clearValue()
 185         {
 186 #ifndef NDEBUG
 187             m_value = noValue();
 188 #endif
 189         }
 190
 191         unsigned index() const { return m_data.index; }
 192
 193     private:
 194         static JSValuePtr functionGetter(ExecState*, const Identifier&, const PropertySlot&);
 195
 196         GetValueFunc m_getValue;
 197
 198         JSValuePtr m_slotBase;
 199         union {
 200             JSObject* getterFunc;
 201             JSValuePtr* valueSlot;
 202             Register* registerSlot;
 203             unsigned index;
 204         } m_data;
 205
 206         JSValuePtr m_value;
 207
 208         size_t m_offset;
 209     };
 210
 211 } // namespace JSC
 212
 213 #endif // PropertySlot_h