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      1 /*
      2  * Copyright (C) 2015 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_SCOPED_GC_CRITICAL_SECTION_H_
     18 #define ART_RUNTIME_GC_SCOPED_GC_CRITICAL_SECTION_H_
     19 
     20 #include "base/locks.h"
     21 #include "collector_type.h"
     22 #include "gc_cause.h"
     23 
     24 namespace art {
     25 
     26 class Thread;
     27 
     28 namespace gc {
     29 
     30 // The use of ScopedGCCriticalSection should be preferred whenever possible.
     31 class GCCriticalSection {
     32  public:
     33   GCCriticalSection(Thread* self, const char* name)
     34       : self_(self), section_name_(name) {}
     35   ~GCCriticalSection() {}
     36 
     37   // Starts a GCCriticalSection. Returns the previous no-suspension reason.
     38   const char* Enter(GcCause cause, CollectorType type) ACQUIRE(Roles::uninterruptible_);
     39 
     40   // Ends a GCCriticalSection. Takes the old no-suspension reason.
     41   void Exit(const char* old_reason) RELEASE(Roles::uninterruptible_);
     42 
     43  private:
     44   Thread* const self_;
     45   const char* section_name_;
     46 };
     47 
     48 // Wait until the GC is finished and then prevent the GC from starting until the destructor. Used
     49 // to prevent deadlocks in places where we call ClassLinker::VisitClass with all the threads
     50 // suspended.
     51 class ScopedGCCriticalSection {
     52  public:
     53   ScopedGCCriticalSection(Thread* self, GcCause cause, CollectorType collector_type)
     54       ACQUIRE(Roles::uninterruptible_);
     55   ~ScopedGCCriticalSection() RELEASE(Roles::uninterruptible_);
     56 
     57  private:
     58   GCCriticalSection critical_section_;
     59   const char* old_no_suspend_reason_;
     60 };
     61 
     62 }  // namespace gc
     63 }  // namespace art
     64 
     65 #endif  // ART_RUNTIME_GC_SCOPED_GC_CRITICAL_SECTION_H_
     66