[keys] Simplify KeyAccumulator

src/keys.h

 // Copyright 2012 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_KEYS_H_
 #define V8_KEYS_H_
 
 #include "src/isolate.h"
 #include "src/objects.h"
 
 namespace v8 {
 namespace internal {
 
-enum AddKeyConversion { DO_NOT_CONVERT, CONVERT_TO_ARRAY_INDEX, PROXY_MAGIC };
+enum AddKeyConversion { DO_NOT_CONVERT, CONVERT_TO_ARRAY_INDEX };
 
 // This is a helper class for JSReceiver::GetKeys which collects and sorts keys.
 // GetKeys needs to sort keys per prototype level, first showing the integer
 // indices from elements then the strings from the properties. However, this
 // does not apply to proxies which are in full control of how the keys are
 // sorted.
 //
 // For performance reasons the KeyAccumulator internally separates integer keys
 // in |elements_| into sorted lists per prototype level. String keys are
 // collected in |string_properties_|, a single OrderedHashSet (similar for
 // Symbols in |symbol_properties_|. To separate the keys per level later when
 // assembling the final list, |levelLengths_| keeps track of the number of
 // String and Symbol keys per level.
 //
 // Only unique keys are kept by the KeyAccumulator, strings are stored in a
 // HashSet for inexpensive lookups. Integer keys are kept in sorted lists which
 // are more compact and allow for reasonably fast includes check.
 class KeyAccumulator final BASE_EMBEDDED {
  public:
   KeyAccumulator(Isolate* isolate, KeyCollectionType type,
                  PropertyFilter filter)
       : isolate_(isolate), type_(type), filter_(filter) {}
   ~KeyAccumulator();
 
-  static MaybeHandle<FixedArray> GetKeys(Handle<JSReceiver> object,
-                                         KeyCollectionType type,
-                                         PropertyFilter filter,
-                                         GetKeysConversion keys_conversion,
-                                         bool filter_proxy_keys);
+  // Computes the enumerable keys for a JSObject. Used for implementing

[Jakob Kummerow, 2016/05/23 16:25:21]

I think this comment is outdated (and overly restrictive). I'd just drop it; the
function's name is as descriptive as it gets here.

[Camillo Bruni, 2016/05/23 19:10:13]

removed.

+  // "for (n in object) { }".
+  static MaybeHandle<FixedArray> GetKeys(
+      Handle<JSReceiver> object, KeyCollectionType type, PropertyFilter filter,
+      GetKeysConversion keys_conversion = KEEP_NUMBERS,
+      bool filter_proxy_keys = true, bool is_for_in = false);
   Handle<FixedArray> GetKeys(GetKeysConversion convert = KEEP_NUMBERS);
   Maybe<bool> CollectKeys(Handle<JSReceiver> receiver,
                           Handle<JSReceiver> object);
-  void CollectOwnElementIndices(Handle<JSObject> object);
-  void CollectOwnPropertyNames(Handle<JSObject> object);
+  Maybe<bool> CollectOwnElementIndices(Handle<JSReceiver> receiver,
+                                       Handle<JSObject> object);
+  Maybe<bool> CollectOwnPropertyNames(Handle<JSReceiver> receiver,
+                                      Handle<JSObject> object);
 
   static Handle<FixedArray> GetEnumPropertyKeys(Isolate* isolate,
                                                 Handle<JSObject> object);
 
-  bool AddKey(uint32_t key);
-  bool AddKey(Object* key, AddKeyConversion convert);
-  bool AddKey(Handle<Object> key, AddKeyConversion convert);
+  void AddKey(Object* key, AddKeyConversion convert = DO_NOT_CONVERT);
+  void AddKey(Handle<Object> key, AddKeyConversion convert = DO_NOT_CONVERT);
   void AddKeys(Handle<FixedArray> array, AddKeyConversion convert);
-  void AddKeys(Handle<JSObject> array, AddKeyConversion convert);
-  void AddElementKeysFromInterceptor(Handle<JSObject> array);
+  void AddKeys(Handle<JSObject> array_like, AddKeyConversion convert);
 
   // Jump to the next level, pushing the current |levelLength_| to
   // |levelLengths_| and adding a new list to |elements_|.
-  void NextPrototype();
-  // Sort the integer indices in the last list in |elements_|
-  void SortCurrentElementsList();
-  int length() { return length_; }
   Isolate* isolate() { return isolate_; }
   PropertyFilter filter() { return filter_; }
   void set_filter_proxy_keys(bool filter) { filter_proxy_keys_ = filter; }
+  void set_is_for_in(bool value) { is_for_in_ = value; }
+  void set_skip_indices(bool value) { skip_indices_ = value; }
 
  private:
   Maybe<bool> CollectOwnKeys(Handle<JSReceiver> receiver,
                              Handle<JSObject> object);
   Maybe<bool> CollectOwnJSProxyKeys(Handle<JSReceiver> receiver,
                                     Handle<JSProxy> proxy);
   Maybe<bool> CollectOwnJSProxyTargetKeys(Handle<JSProxy> proxy,
                                           Handle<JSReceiver> target);
 
   Maybe<bool> AddKeysFromJSProxy(Handle<JSProxy> proxy,
                                  Handle<FixedArray> keys);
 
-  bool AddIntegerKey(uint32_t key);
-  bool AddStringKey(Handle<Object> key, AddKeyConversion convert);
-  bool AddSymbolKey(Handle<Object> array);
-  void SortCurrentElementsListRemoveDuplicates();
+  Handle<OrderedHashSet> keys() { return Handle<OrderedHashSet>::cast(keys_); }
 
   Isolate* isolate_;
+  // keys_ is either an Handle<OrderedHashSet> or in the case of own JSProxy
+  // keys a Handle<FixedArray>.
+  Handle<FixedArray> keys_;
   KeyCollectionType type_;
   PropertyFilter filter_;
   bool filter_proxy_keys_ = true;
-  // |elements_| contains the sorted element keys (indices) per level.
-  std::vector<std::vector<uint32_t>*> elements_;
-  // |protoLengths_| contains the total number of keys (elements + properties)
-  // per level. Negative values mark counts for a level with keys from a proxy.
-  std::vector<int> level_lengths_;
-  // |string_properties_| contains the unique String property keys for all
-  // levels in insertion order per level.
-  Handle<OrderedHashSet> string_properties_;
-  // |symbol_properties_| contains the unique Symbol property keys for all
-  // levels in insertion order per level.
-  Handle<OrderedHashSet> symbol_properties_;
-  Handle<FixedArray> ownProxyKeys_;
-  // |length_| keeps track of the total number of all element and property keys.
-  int length_ = 0;
-  // |levelLength_| keeps track of the number of String keys in the current
-  // level.
-  int level_string_length_ = 0;
-  // |levelSymbolLength_| keeps track of the number of Symbol keys in the
-  // current level.
-  int level_symbol_length_ = 0;
+  bool is_for_in_ = false;
+  bool skip_indices_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(KeyAccumulator);
 };
 
 // The FastKeyAccumulator handles the cases where there are no elements on the
 // prototype chain and forwords the complex/slow cases to the normal
 // KeyAccumulator.
 class FastKeyAccumulator {
  public:
   FastKeyAccumulator(Isolate* isolate, Handle<JSReceiver> receiver,
                      KeyCollectionType type, PropertyFilter filter)
       : isolate_(isolate), receiver_(receiver), type_(type), filter_(filter) {
     Prepare();
   }
 
   bool is_receiver_simple_enum() { return is_receiver_simple_enum_; }
   bool has_empty_prototype() { return has_empty_prototype_; }
   void set_filter_proxy_keys(bool filter) { filter_proxy_keys_ = filter; }
+  void set_is_for_in(bool value) { is_for_in_ = value; }
 
   MaybeHandle<FixedArray> GetKeys(GetKeysConversion convert = KEEP_NUMBERS);
 
  private:
   void Prepare();
   MaybeHandle<FixedArray> GetKeysFast(GetKeysConversion convert);
   MaybeHandle<FixedArray> GetKeysSlow(GetKeysConversion convert);
 
   Isolate* isolate_;
   Handle<JSReceiver> receiver_;
   KeyCollectionType type_;
   PropertyFilter filter_;
   bool filter_proxy_keys_ = true;
+  bool is_for_in_ = false;
   bool is_receiver_simple_enum_ = false;
   bool has_empty_prototype_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(FastKeyAccumulator);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_KEYS_H_