runtime/JSVariableObject.h

   1 /*
   2  * Copyright (C) 2007, 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 JSVariableObject_h
  30 #define JSVariableObject_h
  31
  32 #include "JSObject.h"
  33 #include "Register.h"
  34 #include "SymbolTable.h"
  35 #include "UnusedParam.h"
  36 #include <wtf/OwnArrayPtr.h>
  37 #include <wtf/UnusedParam.h>
  38
  39 namespace JSC {
  40
  41     class Register;
  42
  43     class JSVariableObject : public JSNonFinalObject {
  44         friend class JIT;
  45
  46     public:
  47         SymbolTable& symbolTable() const { return *m_symbolTable; }
  48
  49         virtual void putWithAttributes(ExecState*, const Identifier&, JSValue, unsigned attributes) = 0;
  50
  51         virtual bool deleteProperty(ExecState*, const Identifier&);
  52         virtual void getOwnPropertyNames(ExecState*, PropertyNameArray&, EnumerationMode mode = ExcludeDontEnumProperties);
  53
  54         virtual bool isVariableObject() const;
  55         virtual bool isDynamicScope(bool& requiresDynamicChecks) const = 0;
  56
  57         WriteBarrier<Unknown>& registerAt(int index) const { return m_registers[index]; }
  58
  59         WriteBarrier<Unknown>* const * addressOfRegisters() const { return &m_registers; }
  60
  61         static Structure* createStructure(JSGlobalData& globalData, JSValue prototype)
  62         {
  63             return Structure::create(globalData, prototype, TypeInfo(ObjectType, StructureFlags), AnonymousSlotCount, &s_info);
  64         }
  65
  66     protected:
  67         static const unsigned StructureFlags = OverridesGetPropertyNames | JSObject::StructureFlags;
  68
  69         JSVariableObject(JSGlobalData& globalData, Structure* structure, SymbolTable* symbolTable, Register* registers)
  70             : JSNonFinalObject(globalData, structure)
  71             , m_symbolTable(symbolTable)
  72             , m_registers(reinterpret_cast<WriteBarrier<Unknown>*>(registers))
  73         {
  74             ASSERT(m_symbolTable);
  75             COMPILE_ASSERT(sizeof(WriteBarrier<Unknown>) == sizeof(Register), Register_should_be_same_size_as_WriteBarrier);
  76         }
  77
  78         PassOwnArrayPtr<WriteBarrier<Unknown> > copyRegisterArray(JSGlobalData&, WriteBarrier<Unknown>* src, size_t count, size_t callframeStarts);
  79         void setRegisters(WriteBarrier<Unknown>* registers, PassOwnArrayPtr<WriteBarrier<Unknown> > registerArray);
  80
  81         bool symbolTableGet(const Identifier&, PropertySlot&);
  82         bool symbolTableGet(const Identifier&, PropertyDescriptor&);
  83         bool symbolTableGet(const Identifier&, PropertySlot&, bool& slotIsWriteable);
  84         bool symbolTablePut(JSGlobalData&, const Identifier&, JSValue);
  85         bool symbolTablePutWithAttributes(JSGlobalData&, const Identifier&, JSValue, unsigned attributes);
  86
  87         SymbolTable* m_symbolTable; // Maps name -> offset from "r" in register file.
  88         WriteBarrier<Unknown>* m_registers; // "r" in the register file.
  89         OwnArrayPtr<WriteBarrier<Unknown> > m_registerArray; // Independent copy of registers, used when a variable object copies its registers out of the register file.
  90     };
  91
  92     inline bool JSVariableObject::symbolTableGet(const Identifier& propertyName, PropertySlot& slot)
  93     {
  94         SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
  95         if (!entry.isNull()) {
  96             slot.setValue(registerAt(entry.getIndex()).get());
  97             return true;
  98         }
  99         return false;
 100     }
 101
 102     inline bool JSVariableObject::symbolTableGet(const Identifier& propertyName, PropertySlot& slot, bool& slotIsWriteable)
 103     {
 104         SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
 105         if (!entry.isNull()) {
 106             slot.setValue(registerAt(entry.getIndex()).get());
 107             slotIsWriteable = !entry.isReadOnly();
 108             return true;
 109         }
 110         return false;
 111     }
 112
 113     inline bool JSVariableObject::symbolTablePut(JSGlobalData& globalData, const Identifier& propertyName, JSValue value)
 114     {
 115         ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 116
 117         SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
 118         if (entry.isNull())
 119             return false;
 120         if (entry.isReadOnly())
 121             return true;
 122         registerAt(entry.getIndex()).set(globalData, this, value);
 123         return true;
 124     }
 125
 126     inline bool JSVariableObject::symbolTablePutWithAttributes(JSGlobalData& globalData, const Identifier& propertyName, JSValue value, unsigned attributes)
 127     {
 128         ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 129
 130         SymbolTable::iterator iter = symbolTable().find(propertyName.impl());
 131         if (iter == symbolTable().end())
 132             return false;
 133         SymbolTableEntry& entry = iter->second;
 134         ASSERT(!entry.isNull());
 135         entry.setAttributes(attributes);
 136         registerAt(entry.getIndex()).set(globalData, this, value);
 137         return true;
 138     }
 139
 140     inline PassOwnArrayPtr<WriteBarrier<Unknown> > JSVariableObject::copyRegisterArray(JSGlobalData& globalData, WriteBarrier<Unknown>* src, size_t count, size_t callframeStarts)
 141     {
 142         OwnArrayPtr<WriteBarrier<Unknown> > registerArray = adoptArrayPtr(new WriteBarrier<Unknown>[count]);
 143         for (size_t i = 0; i < callframeStarts; i++)
 144             registerArray[i].set(globalData, this, src[i].get());
 145         for (size_t i = callframeStarts + RegisterFile::CallFrameHeaderSize; i < count; i++)
 146             registerArray[i].set(globalData, this, src[i].get());
 147
 148         return registerArray.release();
 149     }
 150
 151     inline void JSVariableObject::setRegisters(WriteBarrier<Unknown>* registers, PassOwnArrayPtr<WriteBarrier<Unknown> > registerArray)
 152     {
 153         ASSERT(registerArray != m_registerArray);
 154         m_registerArray = registerArray;
 155         m_registers = registers;
 156     }
 157
 158 } // namespace JSC
 159
 160 #endif // JSVariableObject_h