1 // -*- mode: c++; c-basic-offset: 4 -*-
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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.
37 static const unsigned MasqueradesAsUndefined = 1; // WebCore uses MasqueradesAsUndefined to make document.all and style.filter undetectable.
38 static const unsigned ImplementsHasInstance = 1 << 1;
39 static const unsigned OverridesHasInstance = 1 << 2;
40 static const unsigned ImplementsDefaultHasInstance = 1 << 3;
41 static const unsigned IsEnvironmentRecord = 1 << 4;
42 static const unsigned OverridesGetOwnPropertySlot = 1 << 5;
43 static const unsigned OverridesVisitChildren = 1 << 6;
44 static const unsigned OverridesGetPropertyNames = 1 << 7;
45 static const unsigned IsJSFinalObject = 1 << 8;
46 static const unsigned ProhibitsPropertyCaching = 1 << 9;
50 TypeInfo(JSType type, unsigned flags = 0)
52 , m_flags(flags & 0xff)
53 , m_flags2(flags >> 8)
55 ASSERT(flags <= 0x3ff);
57 ASSERT(type >= CompoundType || !(flags & OverridesVisitChildren));
58 // ImplementsDefaultHasInstance means (ImplementsHasInstance & !OverridesHasInstance)
59 if ((m_flags & (ImplementsHasInstance | OverridesHasInstance)) == ImplementsHasInstance)
60 m_flags |= ImplementsDefaultHasInstance;
63 JSType type() const { return (JSType)m_type; }
65 bool masqueradesAsUndefined() const { return m_flags & MasqueradesAsUndefined; }
66 bool implementsHasInstance() const { return m_flags & ImplementsHasInstance; }
67 bool isEnvironmentRecord() const { return m_flags & IsEnvironmentRecord; }
68 bool overridesHasInstance() const { return m_flags & OverridesHasInstance; }
69 bool overridesGetOwnPropertySlot() const { return m_flags & OverridesGetOwnPropertySlot; }
70 bool overridesVisitChildren() const { return m_flags & OverridesVisitChildren; }
71 bool overridesGetPropertyNames() const { return m_flags & OverridesGetPropertyNames; }
72 unsigned isFinal() const { return m_flags2 & (IsJSFinalObject >> 8); }
73 unsigned prohibitsPropertyCaching() const { return m_flags2 & (ProhibitsPropertyCaching >> 8); }
74 unsigned flags() const { return m_flags; }
76 static ptrdiff_t flagsOffset()
78 return OBJECT_OFFSETOF(TypeInfo, m_flags);
81 static ptrdiff_t typeOffset()
83 return OBJECT_OFFSETOF(TypeInfo, m_type);
88 unsigned char m_flags;
89 unsigned char m_flags2;
94 #endif // JSTypeInfo_h