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/*
* Copyright 2016 Google Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef COBALT_SCRIPT_MOZJS_REFERENCED_OBJECT_MAP_H_
#define COBALT_SCRIPT_MOZJS_REFERENCED_OBJECT_MAP_H_
#include "base/hash_tables.h"
#include "base/threading/thread_checker.h"
#include "cobalt/script/mozjs/weak_heap_object.h"
#include "cobalt/script/wrappable.h"
#include "third_party/mozjs/js/src/jsapi.h"
namespace cobalt {
namespace script {
namespace mozjs {
// Maintains a set of JSObjects that are reachable from a given object. This
// relationship is registered by mapping a key to a JSObject. The calling code
// should ensure that a key uniquely identifies the entity that holds a
// reference to the JSObjects.
// During garbage collection, supply a key to TraceReferencedObjects to trace
// all objects that are registered as being reachable from the object
// represented by that key.
class ReferencedObjectMap {
public:
explicit ReferencedObjectMap(JSContext* context);
// Reinterpret the pointer as an integer to be used as a key for tracking
// referenced objects.
static intptr_t GetKeyForWrappable(const Wrappable* wrappable) {
return reinterpret_cast<intptr_t>(wrappable);
}
void AddReferencedObject(intptr_t key, JS::HandleObject referee);
void RemoveReferencedObject(intptr_t key, JS::HandleObject referee);
// Trace all objects referenced from this WrapperPrivate*.
void TraceReferencedObjects(JSTracer* trace, intptr_t key);
// Remove any referenced objects that are NULL. It may be the case that a
// weak reference to an object was garbage collected, so remove it from the
// internal list.
void RemoveNullReferences();
private:
typedef base::hash_multimap<intptr_t, WeakHeapObject>
ReferencedObjectMultiMap;
base::ThreadChecker thread_checker_;
JSContext* context_;
ReferencedObjectMultiMap referenced_objects_;
};
} // namespace mozjs
} // namespace script
} // namespace cobalt
#endif // COBALT_SCRIPT_MOZJS_REFERENCED_OBJECT_MAP_H_