js/src/vm/PropertyResult.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef vm_PropertyResult_h
   8 #define vm_PropertyResult_h
   9
  10 #include "mozilla/Assertions.h"
  11
  12 #include "vm/PropertyInfo.h"
  13
  14 namespace js {
  15
  16 class PropertyResult {
  17   enum class Kind : uint8_t {
  18     NotFound,
  19     NativeProperty,
  20     NonNativeProperty,
  21     DenseElement,
  22     TypedArrayElement,
  23   };
  24   union {
  25     // Set if kind is NativeProperty.
  26     PropertyInfo propInfo_;
  27     // Set if kind is DenseElement.
  28     uint32_t denseIndex_;
  29     // Set if kind is TypedArrayElement.
  30     size_t typedArrayIndex_;
  31   };
  32   Kind kind_ = Kind::NotFound;
  33   bool ignoreProtoChain_ = false;
  34
  35  public:
  36   // Note: because PropertyInfo does not have a default constructor, we can't
  37   // use |= default| here.
  38   PropertyResult() {}
  39
  40   // When a property is not found, we may additionally indicate that the
  41   // prototype chain should be ignored. This occurs for:
  42   //  - An out-of-range numeric property on a TypedArrayObject.
  43   //  - A resolve hook recursively calling itself as it sets the property.
  44   bool isNotFound() const { return kind_ == Kind::NotFound; }
  45   bool shouldIgnoreProtoChain() const {
  46     MOZ_ASSERT(isNotFound());
  47     return ignoreProtoChain_;
  48   }
  49
  50   bool isFound() const { return kind_ != Kind::NotFound; }
  51   bool isNonNativeProperty() const { return kind_ == Kind::NonNativeProperty; }
  52   bool isDenseElement() const { return kind_ == Kind::DenseElement; }
  53   bool isTypedArrayElement() const { return kind_ == Kind::TypedArrayElement; }
  54   bool isNativeProperty() const { return kind_ == Kind::NativeProperty; }
  55
  56   PropertyInfo propertyInfo() const {
  57     MOZ_ASSERT(isNativeProperty());
  58     return propInfo_;
  59   }
  60
  61   uint32_t denseElementIndex() const {
  62     MOZ_ASSERT(isDenseElement());
  63     return denseIndex_;
  64   }
  65
  66   size_t typedArrayElementIndex() const {
  67     MOZ_ASSERT(isTypedArrayElement());
  68     return typedArrayIndex_;
  69   }
  70
  71   void setNotFound() { kind_ = Kind::NotFound; }
  72
  73   void setNativeProperty(PropertyInfo prop) {
  74     kind_ = Kind::NativeProperty;
  75     propInfo_ = prop;
  76   }
  77
  78   void setWasmGcProperty() { kind_ = Kind::NonNativeProperty; }
  79   void setProxyProperty() { kind_ = Kind::NonNativeProperty; }
  80
  81   void setDenseElement(uint32_t index) {
  82     kind_ = Kind::DenseElement;
  83     denseIndex_ = index;
  84   }
  85
  86   void setTypedArrayElement(size_t index) {
  87     kind_ = Kind::TypedArrayElement;
  88     typedArrayIndex_ = index;
  89   }
  90
  91   void setTypedArrayOutOfRange() {
  92     kind_ = Kind::NotFound;
  93     ignoreProtoChain_ = true;
  94   }
  95   void setRecursiveResolve() {
  96     kind_ = Kind::NotFound;
  97     ignoreProtoChain_ = true;
  98   }
  99 };
 100
 101 }  // namespace js
 102
 103 #endif /* vm_PropertyResult_h */