JSCell.cpp revision 2daae5fd11344eaa88a0d92b0f6d65f8d2255c00
1/* 2 * Copyright (C) 1999-2001 Harri Porten (porten@kde.org) 3 * Copyright (C) 2001 Peter Kelly (pmk@post.com) 4 * Copyright (C) 2003, 2007, 2008 Apple Inc. All rights reserved. 5 * 6 * This library is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Library General Public 8 * License as published by the Free Software Foundation; either 9 * version 2 of the License, or (at your option) any later version. 10 * 11 * This library is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Library General Public License for more details. 15 * 16 * You should have received a copy of the GNU Library General Public License 17 * along with this library; see the file COPYING.LIB. If not, write to 18 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 19 * Boston, MA 02110-1301, USA. 20 * 21 */ 22 23#include "config.h" 24#include "JSCell.h" 25 26#include "JSFunction.h" 27#include "JSString.h" 28#include "JSObject.h" 29#include <wtf/MathExtras.h> 30 31namespace JSC { 32 33#if defined NAN && defined INFINITY 34 35extern const double NaN = NAN; 36extern const double Inf = INFINITY; 37 38#else // !(defined NAN && defined INFINITY) 39 40// The trick is to define the NaN and Inf globals with a different type than the declaration. 41// This trick works because the mangled name of the globals does not include the type, although 42// I'm not sure that's guaranteed. There could be alignment issues with this, since arrays of 43// characters don't necessarily need the same alignment doubles do, but for now it seems to work. 44// It would be good to figure out a 100% clean way that still avoids code that runs at init time. 45 46// Note, we have to use union to ensure alignment. Otherwise, NaN_Bytes can start anywhere, 47// while NaN_double has to be 4-byte aligned for 32-bits. 48// With -fstrict-aliasing enabled, unions are the only safe way to do type masquerading. 49 50static const union { 51 struct { 52 unsigned char NaN_Bytes[8]; 53 unsigned char Inf_Bytes[8]; 54 } bytes; 55 56 struct { 57 double NaN_Double; 58 double Inf_Double; 59 } doubles; 60 61} NaNInf = { { 62#if CPU(BIG_ENDIAN) 63 { 0x7f, 0xf8, 0, 0, 0, 0, 0, 0 }, 64 { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 } 65#elif CPU(MIDDLE_ENDIAN) 66 { 0, 0, 0xf8, 0x7f, 0, 0, 0, 0 }, 67 { 0, 0, 0xf0, 0x7f, 0, 0, 0, 0 } 68#else 69 { 0, 0, 0, 0, 0, 0, 0xf8, 0x7f }, 70 { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f } 71#endif 72} } ; 73 74extern const double NaN = NaNInf.doubles.NaN_Double; 75extern const double Inf = NaNInf.doubles.Inf_Double; 76 77#endif // !(defined NAN && defined INFINITY) 78 79bool JSCell::getUInt32(uint32_t&) const 80{ 81 return false; 82} 83 84bool JSCell::getString(ExecState* exec, UString&stringValue) const 85{ 86 if (!isString()) 87 return false; 88 stringValue = static_cast<const JSString*>(this)->value(exec); 89 return true; 90} 91 92UString JSCell::getString(ExecState* exec) const 93{ 94 return isString() ? static_cast<const JSString*>(this)->value(exec) : UString(); 95} 96 97JSObject* JSCell::getObject() 98{ 99 return isObject() ? asObject(this) : 0; 100} 101 102const JSObject* JSCell::getObject() const 103{ 104 return isObject() ? static_cast<const JSObject*>(this) : 0; 105} 106 107CallType JSCell::getCallData(CallData&) 108{ 109 return CallTypeNone; 110} 111 112ConstructType JSCell::getConstructData(ConstructData&) 113{ 114 return ConstructTypeNone; 115} 116 117bool JSCell::getOwnPropertySlot(ExecState* exec, const Identifier& identifier, PropertySlot& slot) 118{ 119 // This is not a general purpose implementation of getOwnPropertySlot. 120 // It should only be called by JSValue::get. 121 // It calls getPropertySlot, not getOwnPropertySlot. 122 JSObject* object = toObject(exec, exec->lexicalGlobalObject()); 123 slot.setBase(object); 124 if (!object->getPropertySlot(exec, identifier, slot)) 125 slot.setUndefined(); 126 return true; 127} 128 129bool JSCell::getOwnPropertySlot(ExecState* exec, unsigned identifier, PropertySlot& slot) 130{ 131 // This is not a general purpose implementation of getOwnPropertySlot. 132 // It should only be called by JSValue::get. 133 // It calls getPropertySlot, not getOwnPropertySlot. 134 JSObject* object = toObject(exec, exec->lexicalGlobalObject()); 135 slot.setBase(object); 136 if (!object->getPropertySlot(exec, identifier, slot)) 137 slot.setUndefined(); 138 return true; 139} 140 141void JSCell::put(ExecState* exec, const Identifier& identifier, JSValue value, PutPropertySlot& slot) 142{ 143 toObject(exec, exec->lexicalGlobalObject())->put(exec, identifier, value, slot); 144} 145 146void JSCell::put(ExecState* exec, unsigned identifier, JSValue value) 147{ 148 toObject(exec, exec->lexicalGlobalObject())->put(exec, identifier, value); 149} 150 151bool JSCell::deleteProperty(ExecState* exec, const Identifier& identifier) 152{ 153 return toObject(exec, exec->lexicalGlobalObject())->deleteProperty(exec, identifier); 154} 155 156bool JSCell::deleteProperty(ExecState* exec, unsigned identifier) 157{ 158 return toObject(exec, exec->lexicalGlobalObject())->deleteProperty(exec, identifier); 159} 160 161JSObject* JSCell::toThisObject(ExecState* exec) const 162{ 163 return toObject(exec, exec->lexicalGlobalObject()); 164} 165 166JSValue JSCell::getJSNumber() 167{ 168 return JSValue(); 169} 170 171bool JSCell::isGetterSetter() const 172{ 173 return false; 174} 175 176JSValue JSCell::toPrimitive(ExecState*, PreferredPrimitiveType) const 177{ 178 ASSERT_NOT_REACHED(); 179 return JSValue(); 180} 181 182bool JSCell::getPrimitiveNumber(ExecState*, double&, JSValue&) 183{ 184 ASSERT_NOT_REACHED(); 185 return false; 186} 187 188bool JSCell::toBoolean(ExecState*) const 189{ 190 ASSERT_NOT_REACHED(); 191 return false; 192} 193 194double JSCell::toNumber(ExecState*) const 195{ 196 ASSERT_NOT_REACHED(); 197 return 0; 198} 199 200UString JSCell::toString(ExecState*) const 201{ 202 ASSERT_NOT_REACHED(); 203 return UString(); 204} 205 206JSObject* JSCell::toObject(ExecState*, JSGlobalObject*) const 207{ 208 ASSERT_NOT_REACHED(); 209 return 0; 210} 211 212bool isZombie(const JSCell* cell) 213{ 214#if ENABLE(JSC_ZOMBIES) 215 return cell && cell->isZombie(); 216#else 217 UNUSED_PARAM(cell); 218 return false; 219#endif 220} 221 222} // namespace JSC 223