1 /*
2  * Copyright (C) 2016 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 CHRE_PLATFORM_MUTEX_H_
18 #define CHRE_PLATFORM_MUTEX_H_
19 
20 #include "chre/target_platform/mutex_base.h"
21 #include "chre/util/non_copyable.h"
22 
23 namespace chre {
24 
25 /**
26  * Provides an implementation of a Mutex. The public API meets the BasicLockable
27  * requirements in order to be compatible with std::lock_guard. MutexBase is
28  * subclassed here to allow platforms to inject their own storage for their
29  * mutex implementation.
30  */
31 class Mutex : public MutexBase,
32               public NonCopyable {
33  public:
34   /**
35    * Allows the platform to do any mutex initialization at construction time.
36    */
37   Mutex();
38 
39   /**
40    * Allows the platform to do any mutex deinitialization at destruction time.
41    */
42   ~Mutex();
43 
44   /**
45    * Locks the mutex, or blocks if it is held by another thread. Illegal to call
46    * if the current thread already holds the lock.
47    */
48   void lock();
49 
50   /**
51    * Attempts to lock the mutex. If it is already held by some other thread,
52    * returns immediately. Illegal to call if the current thread already holds
53    * the lock.
54    *
55    * @return true if the mutex was acquired, false otherwise
56    */
57   bool try_lock();
58 
59   /**
60    * Unlocks the mutex. Illegal to call if the current thread does not hold the
61    * lock.
62    */
63   void unlock();
64 };
65 
66 }  // namespace chre
67 
68 #include "chre/target_platform/mutex_base_impl.h"
69 
70 #endif  // CHRE_PLATFORM_MUTEX_H_
71