1 // -*- mode: c++; c-basic-offset: 4 -*- 2 /* 3 * Copyright (C) 2008 Apple Inc. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 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 * 14 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY 15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR 18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #ifndef JSTypeInfo_h 28 #define JSTypeInfo_h 29 30 // This file would be called TypeInfo.h, but that conflicts with <typeinfo.h> 31 // in the STL on systems without case-sensitive file systems. 32 33 #include "JSType.h" 34 35 namespace JSC { 36 37 // WebCore uses MasqueradesAsUndefined to make document.all and style.filter undetectable. 38 static const unsigned MasqueradesAsUndefined = 1; 39 static const unsigned ImplementsHasInstance = 1 << 1; 40 static const unsigned OverridesHasInstance = 1 << 2; 41 static const unsigned ImplementsDefaultHasInstance = 1 << 3; 42 static const unsigned NeedsThisConversion = 1 << 4; 43 static const unsigned OverridesGetOwnPropertySlot = 1 << 5; 44 static const unsigned OverridesMarkChildren = 1 << 6; 45 static const unsigned OverridesGetPropertyNames = 1 << 7; 46 static const unsigned IsJSFinalObject = 1 << 8; 47 48 class TypeInfo { 49 public: 50 TypeInfo(JSType type, unsigned flags = 0) 51 : m_type(type) 52 , m_flags(flags & 0xFF) 53 , m_flags2(flags >> 8) 54 { 55 ASSERT(flags <= 0x1FF); 56 ASSERT(type <= 0xFF); 57 ASSERT(type >= CompoundType || !(flags & OverridesMarkChildren)); 58 // ImplementsDefaultHasInstance means (ImplementsHasInstance & !OverridesHasInstance) 59 if ((m_flags & (ImplementsHasInstance | OverridesHasInstance)) == ImplementsHasInstance) 60 m_flags |= ImplementsDefaultHasInstance; 61 } 62 63 JSType type() const { return (JSType)m_type; } 64 65 bool masqueradesAsUndefined() const { return m_flags & MasqueradesAsUndefined; } 66 bool implementsHasInstance() const { return m_flags & ImplementsHasInstance; } 67 bool overridesHasInstance() const { return m_flags & OverridesHasInstance; } 68 bool needsThisConversion() const { return m_flags & NeedsThisConversion; } 69 bool overridesGetOwnPropertySlot() const { return m_flags & OverridesGetOwnPropertySlot; } 70 bool overridesMarkChildren() const { return m_flags & OverridesMarkChildren; } 71 bool overridesGetPropertyNames() const { return m_flags & OverridesGetPropertyNames; } 72 unsigned flags() const { return m_flags; } 73 unsigned isFinal() const { return m_flags2 && (IsJSFinalObject >> 8); } 74 75 static ptrdiff_t flagsOffset() 76 { 77 return OBJECT_OFFSETOF(TypeInfo, m_flags); 78 } 79 80 static ptrdiff_t typeOffset() 81 { 82 return OBJECT_OFFSETOF(TypeInfo, m_type); 83 } 84 85 private: 86 unsigned char m_type; 87 unsigned char m_flags; 88 unsigned char m_flags2; 89 }; 90 91 } 92 93 #endif // JSTypeInfo_h 94
