1 // lock.h 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 // 15 // Author: riley (at) google.com (Michael Riley) 16 // 17 // \file 18 // Google-compatibility locking declarations and inline definitions 19 20 #ifndef FST_LIB_LOCK_H__ 21 #define FST_LIB_LOCK_H__ 22 23 #include <fst/compat.h> // for DISALLOW_COPY_AND_ASSIGN 24 25 namespace fst { 26 27 using namespace std; 28 29 // 30 // Single initialization - single-thread implementation 31 // 32 33 typedef int FstOnceType; 34 35 static const int FST_ONCE_INIT = 1; 36 37 inline int FstOnceInit(FstOnceType *once, void (*init)(void)) { 38 if (*once) 39 (*init)(); 40 *once = 0; 41 return 0; 42 } 43 44 // 45 // Thread locking - single-thread (non-)implementation 46 // 47 48 class Mutex { 49 public: 50 Mutex() {} 51 52 private: 53 DISALLOW_COPY_AND_ASSIGN(Mutex); 54 }; 55 56 class MutexLock { 57 public: 58 MutexLock(Mutex *) {} 59 60 private: 61 DISALLOW_COPY_AND_ASSIGN(MutexLock); 62 }; 63 64 // Reference counting - single-thread implementation 65 class RefCounter { 66 public: 67 RefCounter() : count_(1) {} 68 69 int count() const { return count_; } 70 int Incr() const { return ++count_; } 71 int Decr() const { return --count_; } 72 73 private: 74 mutable int count_; 75 76 DISALLOW_COPY_AND_ASSIGN(RefCounter); 77 }; 78 79 } // namespace fst 80 81 #endif // FST_LIB_LOCK_H__ 82
