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      1 // Copyright 2012 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef V8_KEYS_H_
      6 #define V8_KEYS_H_
      7 
      8 #include "src/isolate.h"
      9 #include "src/objects.h"
     10 
     11 namespace v8 {
     12 namespace internal {
     13 
     14 enum AddKeyConversion { DO_NOT_CONVERT, CONVERT_TO_ARRAY_INDEX };
     15 
     16 // This is a helper class for JSReceiver::GetKeys which collects and sorts keys.
     17 // GetKeys needs to sort keys per prototype level, first showing the integer
     18 // indices from elements then the strings from the properties. However, this
     19 // does not apply to proxies which are in full control of how the keys are
     20 // sorted.
     21 //
     22 // For performance reasons the KeyAccumulator internally separates integer keys
     23 // in |elements_| into sorted lists per prototype level. String keys are
     24 // collected in |string_properties_|, a single OrderedHashSet (similar for
     25 // Symbols in |symbol_properties_|. To separate the keys per level later when
     26 // assembling the final list, |levelLengths_| keeps track of the number of
     27 // String and Symbol keys per level.
     28 //
     29 // Only unique keys are kept by the KeyAccumulator, strings are stored in a
     30 // HashSet for inexpensive lookups. Integer keys are kept in sorted lists which
     31 // are more compact and allow for reasonably fast includes check.
     32 class KeyAccumulator final BASE_EMBEDDED {
     33  public:
     34   KeyAccumulator(Isolate* isolate, KeyCollectionMode mode,
     35                  PropertyFilter filter)
     36       : isolate_(isolate), mode_(mode), filter_(filter) {}
     37   ~KeyAccumulator();
     38 
     39   static MaybeHandle<FixedArray> GetKeys(
     40       Handle<JSReceiver> object, KeyCollectionMode mode, PropertyFilter filter,
     41       GetKeysConversion keys_conversion = GetKeysConversion::kKeepNumbers,
     42       bool filter_proxy_keys = true, bool is_for_in = false);
     43 
     44   Handle<FixedArray> GetKeys(
     45       GetKeysConversion convert = GetKeysConversion::kKeepNumbers);
     46   Maybe<bool> CollectKeys(Handle<JSReceiver> receiver,
     47                           Handle<JSReceiver> object);
     48   Maybe<bool> CollectOwnElementIndices(Handle<JSReceiver> receiver,
     49                                        Handle<JSObject> object);
     50   Maybe<bool> CollectOwnPropertyNames(Handle<JSReceiver> receiver,
     51                                       Handle<JSObject> object);
     52   Maybe<bool> CollectAccessCheckInterceptorKeys(
     53       Handle<AccessCheckInfo> access_check_info, Handle<JSReceiver> receiver,
     54       Handle<JSObject> object);
     55 
     56   static Handle<FixedArray> GetEnumPropertyKeys(Isolate* isolate,
     57                                                 Handle<JSObject> object);
     58 
     59   void AddKey(Object* key, AddKeyConversion convert = DO_NOT_CONVERT);
     60   void AddKey(Handle<Object> key, AddKeyConversion convert = DO_NOT_CONVERT);
     61   void AddKeys(Handle<FixedArray> array, AddKeyConversion convert);
     62   void AddKeys(Handle<JSObject> array_like, AddKeyConversion convert);
     63 
     64   // Jump to the next level, pushing the current |levelLength_| to
     65   // |levelLengths_| and adding a new list to |elements_|.
     66   Isolate* isolate() { return isolate_; }
     67   PropertyFilter filter() { return filter_; }
     68   void set_filter_proxy_keys(bool filter) { filter_proxy_keys_ = filter; }
     69   void set_is_for_in(bool value) { is_for_in_ = value; }
     70   void set_skip_indices(bool value) { skip_indices_ = value; }
     71   void set_last_non_empty_prototype(Handle<JSReceiver> object) {
     72     last_non_empty_prototype_ = object;
     73   }
     74 
     75  private:
     76   Maybe<bool> CollectOwnKeys(Handle<JSReceiver> receiver,
     77                              Handle<JSObject> object);
     78   Maybe<bool> CollectOwnJSProxyKeys(Handle<JSReceiver> receiver,
     79                                     Handle<JSProxy> proxy);
     80   Maybe<bool> CollectOwnJSProxyTargetKeys(Handle<JSProxy> proxy,
     81                                           Handle<JSReceiver> target);
     82 
     83   Maybe<bool> AddKeysFromJSProxy(Handle<JSProxy> proxy,
     84                                  Handle<FixedArray> keys);
     85 
     86   Handle<OrderedHashSet> keys() { return Handle<OrderedHashSet>::cast(keys_); }
     87 
     88   Isolate* isolate_;
     89   // keys_ is either an Handle<OrderedHashSet> or in the case of own JSProxy
     90   // keys a Handle<FixedArray>.
     91   Handle<FixedArray> keys_;
     92   Handle<JSReceiver> last_non_empty_prototype_;
     93   KeyCollectionMode mode_;
     94   PropertyFilter filter_;
     95   bool filter_proxy_keys_ = true;
     96   bool is_for_in_ = false;
     97   bool skip_indices_ = false;
     98 
     99   DISALLOW_COPY_AND_ASSIGN(KeyAccumulator);
    100 };
    101 
    102 // The FastKeyAccumulator handles the cases where there are no elements on the
    103 // prototype chain and forwords the complex/slow cases to the normal
    104 // KeyAccumulator.
    105 class FastKeyAccumulator {
    106  public:
    107   FastKeyAccumulator(Isolate* isolate, Handle<JSReceiver> receiver,
    108                      KeyCollectionMode mode, PropertyFilter filter)
    109       : isolate_(isolate), receiver_(receiver), mode_(mode), filter_(filter) {
    110     Prepare();
    111   }
    112 
    113   bool is_receiver_simple_enum() { return is_receiver_simple_enum_; }
    114   bool has_empty_prototype() { return has_empty_prototype_; }
    115   void set_filter_proxy_keys(bool filter) { filter_proxy_keys_ = filter; }
    116   void set_is_for_in(bool value) { is_for_in_ = value; }
    117 
    118   MaybeHandle<FixedArray> GetKeys(
    119       GetKeysConversion convert = GetKeysConversion::kKeepNumbers);
    120 
    121  private:
    122   void Prepare();
    123   MaybeHandle<FixedArray> GetKeysFast(GetKeysConversion convert);
    124   MaybeHandle<FixedArray> GetKeysSlow(GetKeysConversion convert);
    125 
    126   Isolate* isolate_;
    127   Handle<JSReceiver> receiver_;
    128   Handle<JSReceiver> last_non_empty_prototype_;
    129   KeyCollectionMode mode_;
    130   PropertyFilter filter_;
    131   bool filter_proxy_keys_ = true;
    132   bool is_for_in_ = false;
    133   bool is_receiver_simple_enum_ = false;
    134   bool has_empty_prototype_ = false;
    135 
    136   DISALLOW_COPY_AND_ASSIGN(FastKeyAccumulator);
    137 };
    138 
    139 }  // namespace internal
    140 }  // namespace v8
    141 
    142 #endif  // V8_KEYS_H_
    143