1 files changed, 103 insertions, 0 deletions
diff --git a/js/src/vm/PropertyResult.h b/js/src/vm/PropertyResult.h
new file mode 100644
index 0000000000..e9e9b4c1cc
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+++ b/js/src/vm/PropertyResult.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef vm_PropertyResult_h
+#define vm_PropertyResult_h
+
+#include "mozilla/Assertions.h"
+
+#include "vm/PropertyInfo.h"
+
+namespace js {
+
+class PropertyResult {
+  enum class Kind : uint8_t {
+    NotFound,
+    NativeProperty,
+    NonNativeProperty,
+    DenseElement,
+    TypedArrayElement,
+  };
+  union {
+    // Set if kind is NativeProperty.
+    PropertyInfo propInfo_;
+    // Set if kind is DenseElement.
+    uint32_t denseIndex_;
+    // Set if kind is TypedArrayElement.
+    size_t typedArrayIndex_;
+  };
+  Kind kind_ = Kind::NotFound;
+  bool ignoreProtoChain_ = false;
+
+ public:
+  // Note: because PropertyInfo does not have a default constructor, we can't
+  // use |= default| here.
+  PropertyResult() {}
+
+  // When a property is not found, we may additionally indicate that the
+  // prototype chain should be ignored. This occurs for:
+  //  - An out-of-range numeric property on a TypedArrayObject.
+  //  - A resolve hook recursively calling itself as it sets the property.
+  bool isNotFound() const { return kind_ == Kind::NotFound; }
+  bool shouldIgnoreProtoChain() const {
+    MOZ_ASSERT(isNotFound());
+    return ignoreProtoChain_;
+  }
+
+  bool isFound() const { return kind_ != Kind::NotFound; }
+  bool isNonNativeProperty() const { return kind_ == Kind::NonNativeProperty; }
+  bool isDenseElement() const { return kind_ == Kind::DenseElement; }
+  bool isTypedArrayElement() const { return kind_ == Kind::TypedArrayElement; }
+  bool isNativeProperty() const { return kind_ == Kind::NativeProperty; }
+
+  PropertyInfo propertyInfo() const {
+    MOZ_ASSERT(isNativeProperty());
+    return propInfo_;
+  }
+
+  uint32_t denseElementIndex() const {
+    MOZ_ASSERT(isDenseElement());
+    return denseIndex_;
+  }
+
+  size_t typedArrayElementIndex() const {
+    MOZ_ASSERT(isTypedArrayElement());
+    return typedArrayIndex_;
+  }
+
+  void setNotFound() { kind_ = Kind::NotFound; }
+
+  void setNativeProperty(PropertyInfo prop) {
+    kind_ = Kind::NativeProperty;
+    propInfo_ = prop;
+  }
+
+  void setWasmGcProperty() { kind_ = Kind::NonNativeProperty; }
+  void setProxyProperty() { kind_ = Kind::NonNativeProperty; }
+
+  void setDenseElement(uint32_t index) {
+    kind_ = Kind::DenseElement;
+    denseIndex_ = index;
+  }
+
+  void setTypedArrayElement(size_t index) {
+    kind_ = Kind::TypedArrayElement;
+    typedArrayIndex_ = index;
+  }
+
+  void setTypedArrayOutOfRange() {
+    kind_ = Kind::NotFound;
+    ignoreProtoChain_ = true;
+  }
+  void setRecursiveResolve() {
+    kind_ = Kind::NotFound;
+    ignoreProtoChain_ = true;
+  }
+};
+
+}  // namespace js
+
+#endif /* vm_PropertyResult_h */