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// 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_KEY_ACCUMULATOR_H_
#define V8_KEY_ACCUMULATOR_H_
#include "src/isolate.h"
#include "src/objects.h"
namespace v8 {
namespace internal {
enum AddKeyConversion { DO_NOT_CONVERT, CONVERT_TO_ARRAY_INDEX, PROXY_MAGIC };
// 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, PropertyFilter filter)
: isolate_(isolate), filter_(filter) {}
~KeyAccumulator();
bool AddKey(uint32_t key);
bool AddKey(Object* key, AddKeyConversion convert = DO_NOT_CONVERT);
bool AddKey(Handle<Object> key, AddKeyConversion convert = DO_NOT_CONVERT);
void AddKeys(Handle<FixedArray> array,
AddKeyConversion convert = DO_NOT_CONVERT);
void AddKeys(Handle<JSObject> array,
AddKeyConversion convert = DO_NOT_CONVERT);
void AddKeysFromProxy(Handle<JSObject> array);
Maybe<bool> AddKeysFromProxy(Handle<JSProxy> proxy, Handle<FixedArray> keys);
void AddElementKeysFromInterceptor(Handle<JSObject> array);
// 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();
Handle<FixedArray> GetKeys(GetKeysConversion convert = KEEP_NUMBERS);
int length() { return length_; }
Isolate* isolate() { return isolate_; }
private:
bool AddIntegerKey(uint32_t key);
bool AddStringKey(Handle<Object> key, AddKeyConversion convert);
bool AddSymbolKey(Handle<Object> array);
void SortCurrentElementsListRemoveDuplicates();
Isolate* isolate_;
PropertyFilter filter_;
// |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_;
// |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;
DISALLOW_COPY_AND_ASSIGN(KeyAccumulator);
};
} // namespace internal
} // namespace v8
#endif // V8_KEY_ACCUMULATOR_H_
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