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Hiroshi Yamauchi94f7b492014-07-22 18:08:23 -07001/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ART_RUNTIME_GC_ROOT_H_
18#define ART_RUNTIME_GC_ROOT_H_
19
Mathieu Chartierbad02672014-08-25 13:08:22 -070020#include "base/macros.h"
Hiroshi Yamauchi94f7b492014-07-22 18:08:23 -070021#include "base/mutex.h" // For Locks::mutator_lock_.
22#include "object_callbacks.h"
23
24namespace art {
25
26template<class MirrorType>
Mathieu Chartierbad02672014-08-25 13:08:22 -070027class PACKED(4) GcRoot {
Hiroshi Yamauchi94f7b492014-07-22 18:08:23 -070028 public:
29 template<ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
Mathieu Chartierc2e20622014-11-03 11:41:47 -080030 ALWAYS_INLINE MirrorType* Read() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
Hiroshi Yamauchi94f7b492014-07-22 18:08:23 -070031
Mathieu Chartierc2e20622014-11-03 11:41:47 -080032 void VisitRoot(RootCallback* callback, void* arg, uint32_t thread_id, RootType root_type) const {
Mathieu Chartiereb175f72014-10-31 11:49:27 -070033 DCHECK(!IsNull());
Hiroshi Yamauchi94f7b492014-07-22 18:08:23 -070034 callback(reinterpret_cast<mirror::Object**>(&root_), arg, thread_id, root_type);
Mathieu Chartiereb175f72014-10-31 11:49:27 -070035 DCHECK(!IsNull());
Hiroshi Yamauchi94f7b492014-07-22 18:08:23 -070036 }
37
38 // This is only used by IrtIterator.
39 ALWAYS_INLINE MirrorType** AddressWithoutBarrier() {
40 return &root_;
41 }
42
43 bool IsNull() const {
44 // It's safe to null-check it without a read barrier.
45 return root_ == nullptr;
46 }
47
48 ALWAYS_INLINE explicit GcRoot<MirrorType>() : root_(nullptr) {
49 }
50
51 ALWAYS_INLINE explicit GcRoot<MirrorType>(MirrorType* ref)
52 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) : root_(ref) {
53 }
54
55 private:
Mathieu Chartierc2e20622014-11-03 11:41:47 -080056 mutable MirrorType* root_;
Hiroshi Yamauchi94f7b492014-07-22 18:08:23 -070057};
58
59} // namespace art
60
61#endif // ART_RUNTIME_GC_ROOT_H_