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// Copyright 2014 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
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
// Declares a quarantine, which is used to temporarily house allocations after
// they've been freed, permitting use-after-frees to be detected.
#include <vector>
#include "base/logging.h"
namespace agent {
namespace asan {
// The interface that quarantines must satisfy. They store literal copies of
// objects of type |ObjectType|.
// Placing objects in the quarantine and removing them from it are factored
// out as two separate steps. Thus it is possible for a quarantine invariant
// to be invalidated by a call to 'Push', which won't be restored until
// sufficient calls to 'Pop' have been made.
// This has been templated on the object type to allow easier unittesting.
// @tparam ObjectType The type of object stored by the quarantine.
template<typename ObjectType>
class QuarantineInterface {
typedef ObjectType Object;
typedef std::vector<Object> ObjectVector;
// Constructor.
QuarantineInterface() { }
// Virtual destructor.
virtual ~QuarantineInterface() { }
// Places an allocation in the quarantine. This routine must be thread-safe.
// @param The object to place in the quarantine.
// @returns true if the has been accepted by and placed in the quarantine,
// and false if its entry has been refused.
virtual bool Push(const Object& object) = 0;
// Potentially removes an object from the quarantine to maintain the
// invariant. This routine must be thread-safe.
// @param object Is filled in with a copy of the removed object.
// @returns true if an object was removed, false otherwise. If this returns
// false then the cache invariant is satisfied.
virtual bool Pop(Object* object) = 0;
// Removes all objects from the quarantine, placing them in the provided
// vector. This routine must be thread-safe.
virtual void Empty(ObjectVector* objects) = 0;
// The number of objects currently in the quarantine.
// @returns the number of objects in the quarantine.
virtual size_t GetCount() = 0;
// Quarantines in ASAN are typically storing blocks, represented by the address
// of their allocation.
struct BlockHeader; // Forward declaration.
typedef QuarantineInterface<BlockHeader*> BlockQuarantineInterface;
} // namespace asan
} // namespace agent