include/tbb/null_rw_mutex.h

0001 /*
0002     Copyright (c) 2005-2020 Intel Corporation
0003
0004     Licensed under the Apache License, Version 2.0 (the "License");
0005     you may not use this file except in compliance with the License.
0006     You may obtain a copy of the License at
0007
0008         http://www.apache.org/licenses/LICENSE-2.0
0009
0010     Unless required by applicable law or agreed to in writing, software
0011     distributed under the License is distributed on an "AS IS" BASIS,
0012     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0013     See the License for the specific language governing permissions and
0014     limitations under the License.
0015 */
0016
0017 #ifndef __TBB_null_rw_mutex_H
0018 #define __TBB_null_rw_mutex_H
0019
0020 #include "tbb_stddef.h"
0021
0022 namespace tbb {
0023
0024 //! A rw mutex which does nothing
0025 /** A null_rw_mutex is a rw mutex that does nothing and simulates successful operation.
0026     @ingroup synchronization */
0027 class null_rw_mutex : internal::mutex_copy_deprecated_and_disabled {
0028 public:
0029     //! Represents acquisition of a mutex.
0030     class scoped_lock : internal::no_copy {
0031     public:
0032         scoped_lock() {}
0033         scoped_lock( null_rw_mutex& , bool = true ) {}
0034         ~scoped_lock() {}
0035         void acquire( null_rw_mutex& , bool = true ) {}
0036         bool upgrade_to_writer() { return true; }
0037         bool downgrade_to_reader() { return true; }
0038         bool try_acquire( null_rw_mutex& , bool = true ) { return true; }
0039         void release() {}
0040     };
0041
0042     null_rw_mutex() {}
0043
0044     // Mutex traits
0045     static const bool is_rw_mutex = true;
0046     static const bool is_recursive_mutex = true;
0047     static const bool is_fair_mutex = true;
0048 };
0049
0050 }
0051
0052 #endif /* __TBB_null_rw_mutex_H */