runtime/sirt_ref.h

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * 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 ART_RUNTIME_SIRT_REF_H_
#define ART_RUNTIME_SIRT_REF_H_

#include "base/casts.h"
#include "base/logging.h"
#include "base/macros.h"
#include "stack_indirect_reference_table.h"
#include "thread.h"

namespace art {

template<class T>
class SirtRef {
 public:
  SirtRef(Thread* self, T* object, bool should_verify = true);
  ~SirtRef();

  T& operator*() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    return *get();
  }
  T* operator->() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    return get();
  }
  T* get() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    return down_cast<T*>(sirt_.GetReference(0));
  }

  // Returns the old reference.
  T* reset(T* object = nullptr, bool should_verify = true)
      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

 private:
  Thread* const self_;
  StackIndirectReferenceTable sirt_;

  DISALLOW_COPY_AND_ASSIGN(SirtRef);
};

// A version of SirtRef which disables the object verification.
template<class T>
class SirtRefNoVerify : public SirtRef<T> {
 public:
  SirtRefNoVerify(Thread* self, T* object) : SirtRef<T>(self, object, false) {}
  // Returns the old reference.
  T* reset(T* object = nullptr) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    return SirtRef<T>::reset(object, false);
  }
};

}  // namespace art

#endif  // ART_RUNTIME_SIRT_REF_H_