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// 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_PROTOTYPE_H_
#define V8_PROTOTYPE_H_
#include "src/isolate.h"
#include "src/objects.h"
namespace v8 {
namespace internal {
/**
* A class to uniformly access the prototype of any Object and walk its
* prototype chain.
*
* The PrototypeIterator can either start at the prototype (default), or
* include the receiver itself. If a PrototypeIterator is constructed for a
* Map, it will always start at the prototype.
*
* The PrototypeIterator can either run to the null_value(), the first
* non-hidden prototype, or a given object.
*/
class PrototypeIterator {
public:
enum WhereToEnd { END_AT_NULL, END_AT_NON_HIDDEN };
inline PrototypeIterator(Isolate* isolate, Handle<JSReceiver> receiver,
WhereToStart where_to_start = kStartAtPrototype,
WhereToEnd where_to_end = END_AT_NULL);
inline PrototypeIterator(Isolate* isolate, JSReceiver* receiver,
WhereToStart where_to_start = kStartAtPrototype,
WhereToEnd where_to_end = END_AT_NULL);
inline explicit PrototypeIterator(Isolate* isolate, Map* receiver_map,
WhereToEnd where_to_end = END_AT_NULL);
inline explicit PrototypeIterator(Isolate* isolate, Handle<Map> receiver_map,
WhereToEnd where_to_end = END_AT_NULL);
~PrototypeIterator() = default;
inline bool HasAccess() const;
template <typename T = Object>
T* GetCurrent() const {
DCHECK(handle_.is_null());
return T::cast(object_);
}
template <typename T = Object>
static Handle<T> GetCurrent(const PrototypeIterator& iterator) {
DCHECK(!iterator.handle_.is_null());
DCHECK_NULL(iterator.object_);
return Handle<T>::cast(iterator.handle_);
}
inline void Advance();
inline void AdvanceIgnoringProxies();
// Returns false iff a call to JSProxy::GetPrototype throws.
V8_WARN_UNUSED_RESULT inline bool AdvanceFollowingProxies();
V8_WARN_UNUSED_RESULT inline bool
AdvanceFollowingProxiesIgnoringAccessChecks();
bool IsAtEnd() const { return is_at_end_; }
Isolate* isolate() const { return isolate_; }
private:
Isolate* isolate_;
Object* object_;
Handle<Object> handle_;
WhereToEnd where_to_end_;
bool is_at_end_;
int seen_proxies_;
DISALLOW_COPY_AND_ASSIGN(PrototypeIterator);
};
} // namespace internal
} // namespace v8
#endif // V8_PROTOTYPE_H_
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