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 <wtf/UnusedParam.h>
  36 #include <wtf/OwnArrayPtr.h>
  37 #include <wtf/UnusedParam.h>
  38
  39 namespace JSC {
  40
  41     class LLIntOffsetsExtractor;
  42     class Register;
  43
  44     class JSVariableObject : public JSNonFinalObject {
  45         friend class JIT;
  46         friend class LLIntOffsetsExtractor;
  47
  48     public:
  49         typedef JSNonFinalObject Base;
  50
  51         SymbolTable& symbolTable() const { return *m_symbolTable; }
  52
  53         JS_EXPORT_PRIVATE static void destroy(JSCell*);
  54
  55         static NO_RETURN_DUE_TO_ASSERT void putDirectVirtual(JSObject*, ExecState*, const Identifier&, JSValue, unsigned attributes);
  56
  57         JS_EXPORT_PRIVATE static bool deleteProperty(JSCell*, ExecState*, const Identifier&);
  58         JS_EXPORT_PRIVATE static void getOwnPropertyNames(JSObject*, ExecState*, PropertyNameArray&, EnumerationMode);
  59
  60         bool isDynamicScope(bool& requiresDynamicChecks) const;
  61
  62         WriteBarrier<Unknown>& registerAt(int index) const { return m_registers[index]; }
  63
  64         WriteBarrier<Unknown>* const * addressOfRegisters() const { return &m_registers; }
  65         static size_t offsetOfRegisters() { return OBJECT_OFFSETOF(JSVariableObject, m_registers); }
  66
  67         static Structure* createStructure(JSGlobalData& globalData, JSGlobalObject* globalObject, JSValue prototype)
  68         {
  69             return Structure::create(globalData, globalObject, prototype, TypeInfo(VariableObjectType, StructureFlags), &s_info);
  70         }
  71
  72     protected:
  73         static const unsigned StructureFlags = OverridesGetPropertyNames | JSNonFinalObject::StructureFlags;
  74
  75         JSVariableObject(JSGlobalData& globalData, Structure* structure, SymbolTable* symbolTable, Register* registers)
  76             : JSNonFinalObject(globalData, structure)
  77             , m_symbolTable(symbolTable)
  78             , m_registers(reinterpret_cast<WriteBarrier<Unknown>*>(registers))
  79         {
  80         }
  81
  82         void finishCreation(JSGlobalData& globalData)
  83         {
  84             Base::finishCreation(globalData);
  85             ASSERT(m_symbolTable);
  86             COMPILE_ASSERT(sizeof(WriteBarrier<Unknown>) == sizeof(Register), Register_should_be_same_size_as_WriteBarrier);
  87         }
  88
  89         PassOwnArrayPtr<WriteBarrier<Unknown> > copyRegisterArray(JSGlobalData&, WriteBarrier<Unknown>* src, size_t count, size_t callframeStarts);
  90         void setRegisters(WriteBarrier<Unknown>* registers, PassOwnArrayPtr<WriteBarrier<Unknown> > registerArray);
  91
  92         bool symbolTableGet(const Identifier&, PropertySlot&);
  93         JS_EXPORT_PRIVATE bool symbolTableGet(const Identifier&, PropertyDescriptor&);
  94         bool symbolTableGet(const Identifier&, PropertySlot&, bool& slotIsWriteable);
  95         bool symbolTablePut(ExecState*, const Identifier&, JSValue, bool shouldThrow);
  96         bool symbolTablePutWithAttributes(JSGlobalData&, const Identifier&, JSValue, unsigned attributes);
  97
  98         SymbolTable* m_symbolTable; // Maps name -> offset from "r" in register file.
  99         WriteBarrier<Unknown>* m_registers; // "r" in the register file.
 100         OwnArrayPtr<WriteBarrier<Unknown> > m_registerArray; // Independent copy of registers, used when a variable object copies its registers out of the register file.
 101     };
 102
 103     inline bool JSVariableObject::symbolTableGet(const Identifier& propertyName, PropertySlot& slot)
 104     {
 105         SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
 106         if (!entry.isNull()) {
 107             slot.setValue(registerAt(entry.getIndex()).get());
 108             return true;
 109         }
 110         return false;
 111     }
 112
 113     inline bool JSVariableObject::symbolTableGet(const Identifier& propertyName, PropertySlot& slot, bool& slotIsWriteable)
 114     {
 115         SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
 116         if (!entry.isNull()) {
 117             slot.setValue(registerAt(entry.getIndex()).get());
 118             slotIsWriteable = !entry.isReadOnly();
 119             return true;
 120         }
 121         return false;
 122     }
 123
 124     inline bool JSVariableObject::symbolTablePut(ExecState* exec, const Identifier& propertyName, JSValue value, bool shouldThrow)
 125     {
 126         JSGlobalData& globalData = exec->globalData();
 127         ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 128
 129         SymbolTableEntry entry = symbolTable().inlineGet(propertyName.impl());
 130         if (entry.isNull())
 131             return false;
 132         if (entry.isReadOnly()) {
 133             if (shouldThrow)
 134                 throwTypeError(exec, StrictModeReadonlyPropertyWriteError);
 135             return true;
 136         }
 137         registerAt(entry.getIndex()).set(globalData, this, value);
 138         return true;
 139     }
 140
 141     inline bool JSVariableObject::symbolTablePutWithAttributes(JSGlobalData& globalData, const Identifier& propertyName, JSValue value, unsigned attributes)
 142     {
 143         ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 144
 145         SymbolTable::iterator iter = symbolTable().find(propertyName.impl());
 146         if (iter == symbolTable().end())
 147             return false;
 148         SymbolTableEntry& entry = iter->second;
 149         ASSERT(!entry.isNull());
 150         entry.setAttributes(attributes);
 151         registerAt(entry.getIndex()).set(globalData, this, value);
 152         return true;
 153     }
 154
 155     inline PassOwnArrayPtr<WriteBarrier<Unknown> > JSVariableObject::copyRegisterArray(JSGlobalData& globalData, WriteBarrier<Unknown>* src, size_t count, size_t callframeStarts)
 156     {
 157         OwnArrayPtr<WriteBarrier<Unknown> > registerArray = adoptArrayPtr(new WriteBarrier<Unknown>[count]);
 158         for (size_t i = 0; i < callframeStarts; i++)
 159             registerArray[i].set(globalData, this, src[i].get());
 160         for (size_t i = callframeStarts + RegisterFile::CallFrameHeaderSize; i < count; i++)
 161             registerArray[i].set(globalData, this, src[i].get());
 162
 163         return registerArray.release();
 164     }
 165
 166     inline void JSVariableObject::setRegisters(WriteBarrier<Unknown>* registers, PassOwnArrayPtr<WriteBarrier<Unknown> > registerArray)
 167     {
 168         ASSERT(registerArray != m_registerArray);
 169         m_registerArray = registerArray;
 170         m_registers = registers;
 171     }
 172
 173 } // namespace JSC
 174
 175 #endif // JSVariableObject_h