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 JSObject {
  44         friend class JIT;
  45
  46     public:
  47         SymbolTable& symbolTable() const { return *d->symbolTable; }
  48
  49         virtual void putWithAttributes(ExecState*, const Identifier&, JSValuePtr, unsigned attributes) = 0;
  50
  51         virtual bool deleteProperty(ExecState*, const Identifier&);
  52         virtual void getPropertyNames(ExecState*, PropertyNameArray&);
  53
  54         virtual bool isVariableObject() const;
  55         virtual bool isDynamicScope() const = 0;
  56
  57         virtual bool getPropertyAttributes(ExecState*, const Identifier& propertyName, unsigned& attributes) const;
  58
  59         Register& registerAt(int index) const { return d->registers[index]; }
  60
  61     protected:
  62         // Subclasses of JSVariableObject can subclass this struct to add data
  63         // without increasing their own size (since there's a hard limit on the
  64         // size of a JSCell).
  65         struct JSVariableObjectData {
  66             JSVariableObjectData(SymbolTable* symbolTable, Register* registers)
  67                 : symbolTable(symbolTable)
  68                 , registers(registers)
  69             {
  70                 ASSERT(symbolTable);
  71             }
  72
  73             SymbolTable* symbolTable; // Maps name -> offset from "r" in register file.
  74             Register* registers; // "r" in the register file.
  75             OwnArrayPtr<Register> registerArray; // Independent copy of registers, used when a variable object copies its registers out of the register file.
  76
  77         private:
  78             JSVariableObjectData(const JSVariableObjectData&);
  79             JSVariableObjectData& operator=(const JSVariableObjectData&);
  80         };
  81
  82         JSVariableObject(PassRefPtr<Structure> structure, JSVariableObjectData* data)
  83             : JSObject(structure)
  84             , d(data) // Subclass owns this pointer.
  85         {
  86         }
  87
  88         Register* copyRegisterArray(Register* src, size_t count);
  89         void setRegisters(Register* r, Register* registerArray);
  90
  91         bool symbolTableGet(const Identifier&, PropertySlot&);
  92         bool symbolTableGet(const Identifier&, PropertySlot&, bool& slotIsWriteable);
  93         bool symbolTablePut(const Identifier&, JSValuePtr);
  94         bool symbolTablePutWithAttributes(const Identifier&, JSValuePtr, unsigned attributes);
  95
  96         JSVariableObjectData* d;
  97     };
  98
  99     inline bool JSVariableObject::symbolTableGet(const Identifier& propertyName, PropertySlot& slot)
 100     {
 101         SymbolTableEntry entry = symbolTable().inlineGet(propertyName.ustring().rep());
 102         if (!entry.isNull()) {
 103             slot.setRegisterSlot(&registerAt(entry.getIndex()));
 104             return true;
 105         }
 106         return false;
 107     }
 108
 109     inline bool JSVariableObject::symbolTableGet(const Identifier& propertyName, PropertySlot& slot, bool& slotIsWriteable)
 110     {
 111         SymbolTableEntry entry = symbolTable().inlineGet(propertyName.ustring().rep());
 112         if (!entry.isNull()) {
 113             slot.setRegisterSlot(&registerAt(entry.getIndex()));
 114             slotIsWriteable = !entry.isReadOnly();
 115             return true;
 116         }
 117         return false;
 118     }
 119
 120     inline bool JSVariableObject::symbolTablePut(const Identifier& propertyName, JSValuePtr value)
 121     {
 122         ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 123
 124         SymbolTableEntry entry = symbolTable().inlineGet(propertyName.ustring().rep());
 125         if (entry.isNull())
 126             return false;
 127         if (entry.isReadOnly())
 128             return true;
 129         registerAt(entry.getIndex()) = value;
 130         return true;
 131     }
 132
 133     inline bool JSVariableObject::symbolTablePutWithAttributes(const Identifier& propertyName, JSValuePtr value, unsigned attributes)
 134     {
 135         ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 136
 137         SymbolTable::iterator iter = symbolTable().find(propertyName.ustring().rep());
 138         if (iter == symbolTable().end())
 139             return false;
 140         SymbolTableEntry& entry = iter->second;
 141         ASSERT(!entry.isNull());
 142         entry.setAttributes(attributes);
 143         registerAt(entry.getIndex()) = value;
 144         return true;
 145     }
 146
 147     inline Register* JSVariableObject::copyRegisterArray(Register* src, size_t count)
 148     {
 149         Register* registerArray = new Register[count];
 150         memcpy(registerArray, src, count * sizeof(Register));
 151
 152         return registerArray;
 153     }
 154
 155     inline void JSVariableObject::setRegisters(Register* registers, Register* registerArray)
 156     {
 157         ASSERT(registerArray != d->registerArray.get());
 158         d->registerArray.set(registerArray);
 159         d->registers = registers;
 160     }
 161
 162 } // namespace JSC
 163
 164 #endif // JSVariableObject_h