1 /*
2  * Copyright (C) 2012 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_SCOPED_THREAD_STATE_CHANGE_INL_H_
18 #define ART_RUNTIME_SCOPED_THREAD_STATE_CHANGE_INL_H_
19 
20 #include "scoped_thread_state_change.h"
21 
22 #include <android-base/logging.h>
23 
24 #include "base/casts.h"
25 #include "base/mutex.h"
26 #include "jni/jni_env_ext-inl.h"
27 #include "obj_ptr-inl.h"
28 #include "runtime.h"
29 #include "thread-inl.h"
30 
31 namespace art {
32 
ScopedThreadStateChange(Thread * self,ThreadState new_thread_state)33 inline ScopedThreadStateChange::ScopedThreadStateChange(Thread* self, ThreadState new_thread_state)
34     : self_(self), thread_state_(new_thread_state), expected_has_no_thread_(false) {
35   if (UNLIKELY(self_ == nullptr)) {
36     // Value chosen arbitrarily and won't be used in the destructor since thread_ == null.
37     old_thread_state_ = kTerminated;
38     Runtime* runtime = Runtime::Current();
39     CHECK(runtime == nullptr || !runtime->IsStarted() || runtime->IsShuttingDown(self_));
40   } else {
41     DCHECK_EQ(self, Thread::Current());
42     // Read state without locks, ok as state is effectively thread local and we're not interested
43     // in the suspend count (this will be handled in the runnable transitions).
44     old_thread_state_ = self->GetState();
45     if (old_thread_state_ != new_thread_state) {
46       if (new_thread_state == kRunnable) {
47         self_->TransitionFromSuspendedToRunnable();
48       } else if (old_thread_state_ == kRunnable) {
49         self_->TransitionFromRunnableToSuspended(new_thread_state);
50       } else {
51         // A suspended transition to another effectively suspended transition, ok to use Unsafe.
52         self_->SetState(new_thread_state);
53       }
54     }
55   }
56 }
57 
~ScopedThreadStateChange()58 inline ScopedThreadStateChange::~ScopedThreadStateChange() {
59   if (UNLIKELY(self_ == nullptr)) {
60     if (!expected_has_no_thread_) {
61       Runtime* runtime = Runtime::Current();
62       bool shutting_down = (runtime == nullptr) || runtime->IsShuttingDown(nullptr);
63       CHECK(shutting_down);
64     }
65   } else {
66     if (old_thread_state_ != thread_state_) {
67       if (old_thread_state_ == kRunnable) {
68         self_->TransitionFromSuspendedToRunnable();
69       } else if (thread_state_ == kRunnable) {
70         self_->TransitionFromRunnableToSuspended(old_thread_state_);
71       } else {
72         // A suspended transition to another effectively suspended transition, ok to use Unsafe.
73         self_->SetState(old_thread_state_);
74       }
75     }
76   }
77 }
78 
79 template<typename T>
AddLocalReference(ObjPtr<mirror::Object> obj)80 inline T ScopedObjectAccessAlreadyRunnable::AddLocalReference(ObjPtr<mirror::Object> obj) const {
81   Locks::mutator_lock_->AssertSharedHeld(Self());
82   if (kIsDebugBuild) {
83     CHECK(IsRunnable());  // Don't work with raw objects in non-runnable states.
84     DCheckObjIsNotClearedJniWeakGlobal(obj);
85   }
86   return obj == nullptr ? nullptr : Env()->AddLocalReference<T>(obj);
87 }
88 
89 template<typename T>
Decode(jobject obj)90 inline ObjPtr<T> ScopedObjectAccessAlreadyRunnable::Decode(jobject obj) const {
91   Locks::mutator_lock_->AssertSharedHeld(Self());
92   DCHECK(IsRunnable());  // Don't work with raw objects in non-runnable states.
93   return ObjPtr<T>::DownCast(Self()->DecodeJObject(obj));
94 }
95 
IsRunnable()96 inline bool ScopedObjectAccessAlreadyRunnable::IsRunnable() const {
97   return self_->GetState() == kRunnable;
98 }
99 
ScopedObjectAccessAlreadyRunnable(JNIEnv * env)100 inline ScopedObjectAccessAlreadyRunnable::ScopedObjectAccessAlreadyRunnable(JNIEnv* env)
101     : self_(ThreadForEnv(env)), env_(down_cast<JNIEnvExt*>(env)), vm_(env_->GetVm()) {}
102 
ScopedObjectAccessAlreadyRunnable(Thread * self)103 inline ScopedObjectAccessAlreadyRunnable::ScopedObjectAccessAlreadyRunnable(Thread* self)
104     : self_(self),
105       env_(down_cast<JNIEnvExt*>(self->GetJniEnv())),
106       vm_(env_ != nullptr ? env_->GetVm() : nullptr) {}
107 
ScopedObjectAccessUnchecked(JNIEnv * env)108 inline ScopedObjectAccessUnchecked::ScopedObjectAccessUnchecked(JNIEnv* env)
109     : ScopedObjectAccessAlreadyRunnable(env), tsc_(Self(), kRunnable) {
110   Self()->VerifyStack();
111   Locks::mutator_lock_->AssertSharedHeld(Self());
112 }
113 
ScopedObjectAccessUnchecked(Thread * self)114 inline ScopedObjectAccessUnchecked::ScopedObjectAccessUnchecked(Thread* self)
115     : ScopedObjectAccessAlreadyRunnable(self), tsc_(self, kRunnable) {
116   Self()->VerifyStack();
117   Locks::mutator_lock_->AssertSharedHeld(Self());
118 }
119 
ScopedObjectAccess(JNIEnv * env)120 inline ScopedObjectAccess::ScopedObjectAccess(JNIEnv* env) : ScopedObjectAccessUnchecked(env) {}
ScopedObjectAccess(Thread * self)121 inline ScopedObjectAccess::ScopedObjectAccess(Thread* self) : ScopedObjectAccessUnchecked(self) {}
~ScopedObjectAccess()122 inline ScopedObjectAccess::~ScopedObjectAccess() {}
123 
ScopedThreadSuspension(Thread * self,ThreadState suspended_state)124 inline ScopedThreadSuspension::ScopedThreadSuspension(Thread* self, ThreadState suspended_state)
125     : self_(self), suspended_state_(suspended_state) {
126   DCHECK(self_ != nullptr);
127   self_->TransitionFromRunnableToSuspended(suspended_state);
128 }
129 
~ScopedThreadSuspension()130 inline ScopedThreadSuspension::~ScopedThreadSuspension() {
131   DCHECK_EQ(self_->GetState(), suspended_state_);
132   self_->TransitionFromSuspendedToRunnable();
133 }
134 
135 }  // namespace art
136 
137 #endif  // ART_RUNTIME_SCOPED_THREAD_STATE_CHANGE_INL_H_
138