xref: /aosp_15_r20/art/runtime/reflective_handle.h (revision 795d594fd825385562da6b089ea9b2033f3abf5a)
1*795d594fSAndroid Build Coastguard Worker /*
2*795d594fSAndroid Build Coastguard Worker  * Copyright (C) 2014 The Android Open Source Project
3*795d594fSAndroid Build Coastguard Worker  *
4*795d594fSAndroid Build Coastguard Worker  * Licensed under the Apache License, Version 2.0 (the "License");
5*795d594fSAndroid Build Coastguard Worker  * you may not use this file except in compliance with the License.
6*795d594fSAndroid Build Coastguard Worker  * You may obtain a copy of the License at
7*795d594fSAndroid Build Coastguard Worker  *
8*795d594fSAndroid Build Coastguard Worker  *      http://www.apache.org/licenses/LICENSE-2.0
9*795d594fSAndroid Build Coastguard Worker  *
10*795d594fSAndroid Build Coastguard Worker  * Unless required by applicable law or agreed to in writing, software
11*795d594fSAndroid Build Coastguard Worker  * distributed under the License is distributed on an "AS IS" BASIS,
12*795d594fSAndroid Build Coastguard Worker  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13*795d594fSAndroid Build Coastguard Worker  * See the License for the specific language governing permissions and
14*795d594fSAndroid Build Coastguard Worker  * limitations under the License.
15*795d594fSAndroid Build Coastguard Worker  */
16*795d594fSAndroid Build Coastguard Worker 
17*795d594fSAndroid Build Coastguard Worker #ifndef ART_RUNTIME_REFLECTIVE_HANDLE_H_
18*795d594fSAndroid Build Coastguard Worker #define ART_RUNTIME_REFLECTIVE_HANDLE_H_
19*795d594fSAndroid Build Coastguard Worker 
20*795d594fSAndroid Build Coastguard Worker #include "base/macros.h"
21*795d594fSAndroid Build Coastguard Worker #include "base/value_object.h"
22*795d594fSAndroid Build Coastguard Worker #include "reflective_reference.h"
23*795d594fSAndroid Build Coastguard Worker 
24*795d594fSAndroid Build Coastguard Worker namespace art HIDDEN {
25*795d594fSAndroid Build Coastguard Worker 
26*795d594fSAndroid Build Coastguard Worker // This is a holder similar to Handle<T> that is used to hold reflective references to ArtField and
27*795d594fSAndroid Build Coastguard Worker // ArtMethod structures. A reflective reference is one that must be updated if the underlying class
28*795d594fSAndroid Build Coastguard Worker // or instances are replaced due to structural redefinition or some other process. In general these
29*795d594fSAndroid Build Coastguard Worker // don't need to be used. It's only when it's important that a reference to a field not become
30*795d594fSAndroid Build Coastguard Worker // obsolete and it needs to be held over a suspend point that this should be used.
31*795d594fSAndroid Build Coastguard Worker template <typename T>
32*795d594fSAndroid Build Coastguard Worker class ReflectiveHandle : public ValueObject {
33*795d594fSAndroid Build Coastguard Worker  public:
34*795d594fSAndroid Build Coastguard Worker   static_assert(std::is_same_v<T, ArtField> || std::is_same_v<T, ArtMethod>,
35*795d594fSAndroid Build Coastguard Worker                 "Expected ArtField or ArtMethod");
36*795d594fSAndroid Build Coastguard Worker 
ReflectiveHandle()37*795d594fSAndroid Build Coastguard Worker   ReflectiveHandle() : reference_(nullptr) {}
38*795d594fSAndroid Build Coastguard Worker 
39*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE ReflectiveHandle(const ReflectiveHandle<T>& handle) = default;
40*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE ReflectiveHandle<T>& operator=(const ReflectiveHandle<T>& handle) = default;
41*795d594fSAndroid Build Coastguard Worker 
ReflectiveHandle(ReflectiveReference<T> * reference)42*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE explicit ReflectiveHandle(ReflectiveReference<T>* reference)
43*795d594fSAndroid Build Coastguard Worker       : reference_(reference) {}
44*795d594fSAndroid Build Coastguard Worker 
REQUIRES_SHARED(Locks::mutator_lock_)45*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE T& operator*() const REQUIRES_SHARED(Locks::mutator_lock_) {
46*795d594fSAndroid Build Coastguard Worker     return *Get();
47*795d594fSAndroid Build Coastguard Worker   }
48*795d594fSAndroid Build Coastguard Worker 
49*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE T* operator->() const REQUIRES_SHARED(Locks::mutator_lock_) {
50*795d594fSAndroid Build Coastguard Worker     return Get();
51*795d594fSAndroid Build Coastguard Worker   }
52*795d594fSAndroid Build Coastguard Worker 
Get()53*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE T* Get() const REQUIRES_SHARED(Locks::mutator_lock_) {
54*795d594fSAndroid Build Coastguard Worker     return reference_->Ptr();
55*795d594fSAndroid Build Coastguard Worker   }
56*795d594fSAndroid Build Coastguard Worker 
IsNull()57*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE bool IsNull() const {
58*795d594fSAndroid Build Coastguard Worker     // It's safe to null-check it without a read barrier.
59*795d594fSAndroid Build Coastguard Worker     return reference_->IsNull();
60*795d594fSAndroid Build Coastguard Worker   }
61*795d594fSAndroid Build Coastguard Worker 
62*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE bool operator!=(std::nullptr_t) const REQUIRES_SHARED(Locks::mutator_lock_) {
63*795d594fSAndroid Build Coastguard Worker     return !IsNull();
64*795d594fSAndroid Build Coastguard Worker   }
65*795d594fSAndroid Build Coastguard Worker 
66*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE bool operator==(std::nullptr_t) const REQUIRES_SHARED(Locks::mutator_lock_) {
67*795d594fSAndroid Build Coastguard Worker     return IsNull();
68*795d594fSAndroid Build Coastguard Worker   }
69*795d594fSAndroid Build Coastguard Worker 
70*795d594fSAndroid Build Coastguard Worker  protected:
71*795d594fSAndroid Build Coastguard Worker   ReflectiveReference<T>* reference_;
72*795d594fSAndroid Build Coastguard Worker 
73*795d594fSAndroid Build Coastguard Worker  private:
74*795d594fSAndroid Build Coastguard Worker   friend class BaseReflectiveHandleScope;
75*795d594fSAndroid Build Coastguard Worker   template <size_t kNumFieldReferences, size_t kNumMethodReferences>
76*795d594fSAndroid Build Coastguard Worker   friend class StackReflectiveHandleScope;
77*795d594fSAndroid Build Coastguard Worker };
78*795d594fSAndroid Build Coastguard Worker 
79*795d594fSAndroid Build Coastguard Worker // Handles that support assignment.
80*795d594fSAndroid Build Coastguard Worker template <typename T>
81*795d594fSAndroid Build Coastguard Worker class MutableReflectiveHandle : public ReflectiveHandle<T> {
82*795d594fSAndroid Build Coastguard Worker  public:
MutableReflectiveHandle()83*795d594fSAndroid Build Coastguard Worker   MutableReflectiveHandle() {}
84*795d594fSAndroid Build Coastguard Worker 
85*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE MutableReflectiveHandle(const MutableReflectiveHandle<T>& handle) = default;
86*795d594fSAndroid Build Coastguard Worker 
87*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE MutableReflectiveHandle<T>& operator=(const MutableReflectiveHandle<T>& handle)
88*795d594fSAndroid Build Coastguard Worker       = default;
89*795d594fSAndroid Build Coastguard Worker 
MutableReflectiveHandle(ReflectiveReference<T> * reference)90*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE explicit MutableReflectiveHandle(ReflectiveReference<T>* reference)
91*795d594fSAndroid Build Coastguard Worker       : ReflectiveHandle<T>(reference) {}
92*795d594fSAndroid Build Coastguard Worker 
Assign(T * reference)93*795d594fSAndroid Build Coastguard Worker   ALWAYS_INLINE T* Assign(T* reference) REQUIRES_SHARED(Locks::mutator_lock_) {
94*795d594fSAndroid Build Coastguard Worker     ReflectiveReference<T>* ref = ReflectiveHandle<T>::reference_;
95*795d594fSAndroid Build Coastguard Worker     T* old = ref->Ptr();
96*795d594fSAndroid Build Coastguard Worker     ref->Assign(reference);
97*795d594fSAndroid Build Coastguard Worker     return old;
98*795d594fSAndroid Build Coastguard Worker   }
99*795d594fSAndroid Build Coastguard Worker 
100*795d594fSAndroid Build Coastguard Worker  private:
101*795d594fSAndroid Build Coastguard Worker   friend class BaseReflectiveHandleScope;
102*795d594fSAndroid Build Coastguard Worker   template <size_t kNumFieldReferences, size_t kNumMethodReferences>
103*795d594fSAndroid Build Coastguard Worker   friend class StackReflectiveHandleScope;
104*795d594fSAndroid Build Coastguard Worker };
105*795d594fSAndroid Build Coastguard Worker 
106*795d594fSAndroid Build Coastguard Worker template<typename T>
107*795d594fSAndroid Build Coastguard Worker class ReflectiveHandleWrapper : public MutableReflectiveHandle<T> {
108*795d594fSAndroid Build Coastguard Worker  public:
ReflectiveHandleWrapper(T ** obj,const MutableReflectiveHandle<T> & handle)109*795d594fSAndroid Build Coastguard Worker   ReflectiveHandleWrapper(T** obj, const MutableReflectiveHandle<T>& handle)
110*795d594fSAndroid Build Coastguard Worker      : MutableReflectiveHandle<T>(handle), obj_(obj) {
111*795d594fSAndroid Build Coastguard Worker   }
112*795d594fSAndroid Build Coastguard Worker 
113*795d594fSAndroid Build Coastguard Worker   ReflectiveHandleWrapper(const ReflectiveHandleWrapper&) = default;
114*795d594fSAndroid Build Coastguard Worker 
~ReflectiveHandleWrapper()115*795d594fSAndroid Build Coastguard Worker   ~ReflectiveHandleWrapper() {
116*795d594fSAndroid Build Coastguard Worker     *obj_ = MutableReflectiveHandle<T>::Get();
117*795d594fSAndroid Build Coastguard Worker   }
118*795d594fSAndroid Build Coastguard Worker 
119*795d594fSAndroid Build Coastguard Worker  private:
120*795d594fSAndroid Build Coastguard Worker   T** const obj_;
121*795d594fSAndroid Build Coastguard Worker };
122*795d594fSAndroid Build Coastguard Worker 
123*795d594fSAndroid Build Coastguard Worker }  // namespace art
124*795d594fSAndroid Build Coastguard Worker 
125*795d594fSAndroid Build Coastguard Worker #endif  // ART_RUNTIME_REFLECTIVE_HANDLE_H_
126