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Ian Rogersef7d42f2014-01-06 12:55:46 -08001/*
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_MIRROR_OBJECT_REFERENCE_H_
18#define ART_RUNTIME_MIRROR_OBJECT_REFERENCE_H_
19
Ian Rogersb0fa5dc2014-04-28 16:47:08 -070020#include "base/mutex.h" // For Locks::mutator_lock_.
Hiroshi Yamauchie63a7452014-02-27 14:44:36 -080021#include "globals.h"
Ian Rogersef7d42f2014-01-06 12:55:46 -080022
23namespace art {
24namespace mirror {
25
26class Object;
27
28// Classes shared with the managed side of the world need to be packed so that they don't have
29// extra platform specific padding.
30#define MANAGED PACKED(4)
31
32// Value type representing a reference to a mirror::Object of type MirrorType.
33template<bool kPoisonReferences, class MirrorType>
34class MANAGED ObjectReference {
35 public:
36 MirrorType* AsMirrorPtr() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
37 return UnCompress();
38 }
39
40 void Assign(MirrorType* other) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
41 reference_ = Compress(other);
42 }
43
44 void Clear() {
45 reference_ = 0;
46 }
47
48 uint32_t AsVRegValue() const {
49 return reference_;
50 }
51
52 protected:
53 ObjectReference<kPoisonReferences, MirrorType>(MirrorType* mirror_ptr)
54 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
55 : reference_(Compress(mirror_ptr)) {
56 }
57
58 // Compress reference to its bit representation.
59 static uint32_t Compress(MirrorType* mirror_ptr) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
60 uintptr_t as_bits = reinterpret_cast<uintptr_t>(mirror_ptr);
61 return static_cast<uint32_t>(kPoisonReferences ? -as_bits : as_bits);
62 }
63
64 // Uncompress an encoded reference from its bit representation.
65 MirrorType* UnCompress() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
66 uintptr_t as_bits = kPoisonReferences ? -reference_ : reference_;
67 return reinterpret_cast<MirrorType*>(as_bits);
68 }
69
70 friend class Object;
71
72 // The encoded reference to a mirror::Object.
73 uint32_t reference_;
74};
75
76// References between objects within the managed heap.
77template<class MirrorType>
Hiroshi Yamauchie63a7452014-02-27 14:44:36 -080078class MANAGED HeapReference : public ObjectReference<kPoisonHeapReferences, MirrorType> {
Ian Rogersef7d42f2014-01-06 12:55:46 -080079 public:
80 static HeapReference<MirrorType> FromMirrorPtr(MirrorType* mirror_ptr)
81 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
82 return HeapReference<MirrorType>(mirror_ptr);
83 }
84 private:
85 HeapReference<MirrorType>(MirrorType* mirror_ptr) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
Hiroshi Yamauchie63a7452014-02-27 14:44:36 -080086 : ObjectReference<kPoisonHeapReferences, MirrorType>(mirror_ptr) {}
Ian Rogersef7d42f2014-01-06 12:55:46 -080087};
88
89} // namespace mirror
90} // namespace art
91
92#endif // ART_RUNTIME_MIRROR_OBJECT_REFERENCE_H_