Implement LookupIterator designed to replace LookupResult

src/lookup.h

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_LOOKUP_H_
+#define V8_LOOKUP_H_
+
+#include "src/factory.h"
+#include "src/isolate.h"
+#include "src/objects.h"
+
+namespace v8 {
+namespace internal {
+
+class LookupIterator V8_FINAL BASE_EMBEDDED {
+ public:
+  enum Type {
+    CHECK_DERIVED      = 1 << 0,
+    CHECK_INTERCEPTOR  = 1 << 1,
+    CHECK_ACCESS_CHECK = 1 << 2,
+    CHECK_OWN_REAL     = 0,
+    CHECK_ALL          = CHECK_DERIVED | CHECK_INTERCEPTOR | CHECK_ACCESS_CHECK,
+    SKIP_INTERCEPTOR   = CHECK_ALL ^ CHECK_INTERCEPTOR
+  };
+
+  enum State {
+    NOT_FOUND,
+    PROPERTY,
+    INTERCEPTOR,
+    ACCESS_CHECK,
+    JSPROXY
+  };
+
+  enum PropertyType {
+    DATA,
+    ACCESSORS
+  };
+
+  enum PropertyEncoding {
+    DICTIONARY,
+    DESCRIPTOR
+  };
+
+  LookupIterator(Handle<Object> receiver,
+                 Handle<Name> name,
+                 Type type = CHECK_ALL)
+      : type_(type),
+        state_(NOT_FOUND),
+        has_property_(false),
+        property_type_(DATA),
+        property_encoding_(DESCRIPTOR),
+        property_details_(NONE, NONEXISTENT, Representation::None()),
+        isolate_(name->GetIsolate()),
+        name_(name),
+        maybe_receiver_(receiver),
+        number_(DescriptorArray::kNotFound) {
+    Handle<JSReceiver> origin = GetOrigin();
+    holder_map_ = handle(origin->map());
+    maybe_holder_ = origin;
+    ContinueLookup();
+  }
+
+  LookupIterator(Handle<Object> receiver,
+                 Handle<Name> name,
+                 Handle<JSReceiver> holder,
+                 Type type = CHECK_ALL)
+      : type_(type),
+        state_(NOT_FOUND),
+        has_property_(false),
+        property_type_(DATA),
+        property_encoding_(DESCRIPTOR),
+        property_details_(NONE, NONEXISTENT, Representation::None()),
+        isolate_(name->GetIsolate()),
+        name_(name),
+        holder_map_(holder->map()),
+        maybe_receiver_(receiver),
+        maybe_holder_(holder),
+        number_(DescriptorArray::kNotFound) {
+    ContinueLookup();
+  }
+
+  Isolate* isolate() const { return isolate_; }
+  State state() const { return state_; }
+  Handle<Name> name() const { return name_; }
+
+  bool IsFound() const { return state_ != NOT_FOUND; }
+  void Next();
+
+  Heap* heap() const { return isolate_->heap(); }
+  Factory* factory() const { return isolate_->factory(); }
+  Handle<Object> GetReceiver() const {
+    return Handle<Object>::cast(maybe_receiver_.ToHandleChecked());
+  }
+  Handle<JSObject> GetHolder() const {
+    ASSERT(IsFound() && state_ != JSPROXY);
+    return Handle<JSObject>::cast(maybe_holder_.ToHandleChecked());
+  }
+  Handle<JSReceiver> GetOrigin() const;
+
+  /* ACCESS_CHECK */
+  bool HasAccess(v8::AccessType access_type) const;
+
+  /* PROPERTY */
+  // HasProperty needs to be called before any of the other PROPERTY methods
+  // below can be used. It ensures that we are able to provide a definite
+  // answer, and loads extra information about the property.
+  bool HasProperty();
+  PropertyType property_type() const {
+    ASSERT(has_property_);
+    return property_type_;
+  }
+  PropertyDetails property_details() const {
+    ASSERT(has_property_);
+    return property_details_;
+  }
+  Handle<Object> GetAccessors() const;
+  Handle<Object> GetDataValue() const;
+
+  /* JSPROXY */
+
+  Handle<JSProxy> GetJSProxy() const {
+    return Handle<JSProxy>::cast(maybe_holder_.ToHandleChecked());
+  }
+
+ private:
+  Handle<Map> GetReceiverMap() const;
+
+  MUST_USE_RESULT bool NextHolder();
+  void ContinueLookup();
+  void LookupInHolder();
+  void LookupOwnRealNamedProperty();
+  void FetchDetails();
+  Handle<Object> FetchValue() const;
+
+  bool IsBootstrapping() const;
+
+  // Methods that fetch data from the holder ensure they always have a holder.
+  // This means the receiver needs to be present as opposed to just the receiver
+  // map. Other objects in the prototype chain are transitively guaranteed to be
+  // present via the receiver map.
+  bool is_guaranteed_to_have_holder() const {
+    return !maybe_receiver_.is_null();
+  }
+  bool check_interceptor() const {
+    return !IsBootstrapping() && (type_ & CHECK_INTERCEPTOR) != 0;
+  }
+  bool check_derived() const {
+    return (type_ & CHECK_DERIVED) != 0;
+  }
+  bool check_access_check() const {
+    return (type_ & CHECK_ACCESS_CHECK) != 0;
+  }
+
+  Type type_;
+  State state_;
+  bool has_property_;
+  PropertyType property_type_;
+  PropertyEncoding property_encoding_;
+  PropertyDetails property_details_;
+  Isolate* isolate_;
+  Handle<Name> name_;
+  Handle<Map> holder_map_;
+  MaybeHandle<Object> maybe_receiver_;
+  MaybeHandle<JSReceiver> maybe_holder_;
+
+  int number_;
+};
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_LOOKUP_H_