runtime/PropertyDescriptor.cpp

   1 /*
   2  * Copyright (C) 2009 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  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26
  27 #include "config.h"
  28
  29 #include "PropertyDescriptor.h"
  30
  31 #include "GetterSetter.h"
  32 #include "JSObject.h"
  33 #include "Operations.h"
  34
  35 namespace JSC {
  36 unsigned PropertyDescriptor::defaultAttributes = (DontDelete << 1) - 1;
  37
  38 bool PropertyDescriptor::writable() const
  39 {
  40     ASSERT(!isAccessorDescriptor());
  41     return !(m_attributes & ReadOnly);
  42 }
  43
  44 bool PropertyDescriptor::enumerable() const
  45 {
  46     return !(m_attributes & DontEnum);
  47 }
  48
  49 bool PropertyDescriptor::configurable() const
  50 {
  51     return !(m_attributes & DontDelete);
  52 }
  53
  54 bool PropertyDescriptor::isDataDescriptor() const
  55 {
  56     return m_value || (m_seenAttributes & WritablePresent);
  57 }
  58
  59 bool PropertyDescriptor::isGenericDescriptor() const
  60 {
  61     return !isAccessorDescriptor() && !isDataDescriptor();
  62 }
  63
  64 bool PropertyDescriptor::isAccessorDescriptor() const
  65 {
  66     return m_getter || m_setter;
  67 }
  68
  69 void PropertyDescriptor::setUndefined()
  70 {
  71     m_value = jsUndefined();
  72     m_attributes = ReadOnly | DontDelete | DontEnum;
  73 }
  74
  75 JSValue PropertyDescriptor::getter() const
  76 {
  77     ASSERT(isAccessorDescriptor());
  78     return m_getter;
  79 }
  80
  81 JSValue PropertyDescriptor::setter() const
  82 {
  83     ASSERT(isAccessorDescriptor());
  84     return m_setter;
  85 }
  86
  87 void PropertyDescriptor::setDescriptor(JSValue value, unsigned attributes)
  88 {
  89     ASSERT(value);
  90     m_attributes = attributes;
  91     if (attributes & (Getter | Setter)) {
  92         GetterSetter* accessor = asGetterSetter(value);
  93         m_getter = accessor->getter();
  94         m_setter = accessor->setter();
  95         ASSERT(m_getter || m_setter);
  96         m_seenAttributes = EnumerablePresent | ConfigurablePresent;
  97         m_attributes &= ~ReadOnly;
  98     } else {
  99         m_value = value;
 100         m_seenAttributes = EnumerablePresent | ConfigurablePresent | WritablePresent;
 101     }
 102 }
 103
 104 void PropertyDescriptor::setAccessorDescriptor(JSValue getter, JSValue setter, unsigned attributes)
 105 {
 106     ASSERT(attributes & (Getter | Setter));
 107     ASSERT(getter || setter);
 108     m_attributes = attributes;
 109     m_getter = getter;
 110     m_setter = setter;
 111     m_attributes &= ~ReadOnly;
 112     m_seenAttributes = EnumerablePresent | ConfigurablePresent;
 113 }
 114
 115 void PropertyDescriptor::setWritable(bool writable)
 116 {
 117     if (writable)
 118         m_attributes &= ~ReadOnly;
 119     else
 120         m_attributes |= ReadOnly;
 121     m_seenAttributes |= WritablePresent;
 122 }
 123
 124 void PropertyDescriptor::setEnumerable(bool enumerable)
 125 {
 126     if (enumerable)
 127         m_attributes &= ~DontEnum;
 128     else
 129         m_attributes |= DontEnum;
 130     m_seenAttributes |= EnumerablePresent;
 131 }
 132
 133 void PropertyDescriptor::setConfigurable(bool configurable)
 134 {
 135     if (configurable)
 136         m_attributes &= ~DontDelete;
 137     else
 138         m_attributes |= DontDelete;
 139     m_seenAttributes |= ConfigurablePresent;
 140 }
 141
 142 void PropertyDescriptor::setSetter(JSValue setter)
 143 {
 144     m_setter = setter;
 145     m_attributes |= Setter;
 146     m_attributes &= ~ReadOnly;
 147 }
 148
 149 void PropertyDescriptor::setGetter(JSValue getter)
 150 {
 151     m_getter = getter;
 152     m_attributes |= Getter;
 153     m_attributes &= ~ReadOnly;
 154 }
 155
 156 bool PropertyDescriptor::equalTo(ExecState* exec, const PropertyDescriptor& other) const
 157 {
 158     if (!other.m_value == m_value ||
 159         !other.m_getter == m_getter ||
 160         !other.m_setter == m_setter)
 161         return false;
 162     return (!m_value || JSValue::strictEqual(exec, other.m_value, m_value)) &&
 163            (!m_getter || JSValue::strictEqual(exec, other.m_getter, m_getter)) &&
 164            (!m_setter || JSValue::strictEqual(exec, other.m_setter, m_setter)) &&
 165            attributesEqual(other);
 166 }
 167
 168 bool PropertyDescriptor::attributesEqual(const PropertyDescriptor& other) const
 169 {
 170     unsigned mismatch = other.m_attributes ^ m_attributes;
 171     unsigned sharedSeen = other.m_seenAttributes & m_seenAttributes;
 172     if (sharedSeen & WritablePresent && mismatch & ReadOnly)
 173         return false;
 174     if (sharedSeen & ConfigurablePresent && mismatch & DontDelete)
 175         return false;
 176     if (sharedSeen & EnumerablePresent && mismatch & DontEnum)
 177         return false;
 178     return true;
 179 }
 180
 181 unsigned PropertyDescriptor::attributesWithOverride(const PropertyDescriptor& other) const
 182 {
 183     unsigned mismatch = other.m_attributes ^ m_attributes;
 184     unsigned sharedSeen = other.m_seenAttributes & m_seenAttributes;
 185     unsigned newAttributes = m_attributes & defaultAttributes;
 186     if (sharedSeen & WritablePresent && mismatch & ReadOnly)
 187         newAttributes ^= ReadOnly;
 188     if (sharedSeen & ConfigurablePresent && mismatch & DontDelete)
 189         newAttributes ^= DontDelete;
 190     if (sharedSeen & EnumerablePresent && mismatch & DontEnum)
 191         newAttributes ^= DontEnum;
 192     return newAttributes;
 193 }
 194
 195 }