158 lines
4.4 KiB
C++
158 lines
4.4 KiB
C++
/*
|
|
* Copyright (C) 2007 The Android Open Source Project
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#ifndef _LIBS_UTILS_MUTEX_H
|
|
#define _LIBS_UTILS_MUTEX_H
|
|
|
|
#include <stdint.h>
|
|
#include <sys/types.h>
|
|
#include <time.h>
|
|
|
|
#if defined(HAVE_PTHREADS)
|
|
# include <pthread.h>
|
|
#endif
|
|
|
|
#include <utils/Errors.h>
|
|
#include <utils/Timers.h>
|
|
|
|
// ---------------------------------------------------------------------------
|
|
namespace android {
|
|
// ---------------------------------------------------------------------------
|
|
|
|
class Condition;
|
|
|
|
/*
|
|
* Simple mutex class. The implementation is system-dependent.
|
|
*
|
|
* The mutex must be unlocked by the thread that locked it. They are not
|
|
* recursive, i.e. the same thread can't lock it multiple times.
|
|
*/
|
|
class Mutex {
|
|
public:
|
|
enum {
|
|
PRIVATE = 0,
|
|
SHARED = 1
|
|
};
|
|
|
|
Mutex();
|
|
Mutex(const char* name);
|
|
Mutex(int type, const char* name = NULL);
|
|
~Mutex();
|
|
|
|
// lock or unlock the mutex
|
|
status_t lock();
|
|
void unlock();
|
|
|
|
// lock if possible; returns 0 on success, error otherwise
|
|
status_t tryLock();
|
|
|
|
#if HAVE_ANDROID_OS
|
|
// lock the mutex, but don't wait longer than timeoutMilliseconds.
|
|
// Returns 0 on success, TIMED_OUT for failure due to timeout expiration.
|
|
//
|
|
// OSX doesn't have pthread_mutex_timedlock() or equivalent. To keep
|
|
// capabilities consistent across host OSes, this method is only available
|
|
// when building Android binaries.
|
|
status_t timedLock(nsecs_t timeoutMilliseconds);
|
|
#endif
|
|
|
|
// Manages the mutex automatically. It'll be locked when Autolock is
|
|
// constructed and released when Autolock goes out of scope.
|
|
class Autolock {
|
|
public:
|
|
inline Autolock(Mutex& mutex) : mLock(mutex) { mLock.lock(); }
|
|
inline Autolock(Mutex* mutex) : mLock(*mutex) { mLock.lock(); }
|
|
inline ~Autolock() { mLock.unlock(); }
|
|
private:
|
|
Mutex& mLock;
|
|
};
|
|
|
|
private:
|
|
friend class Condition;
|
|
|
|
// A mutex cannot be copied
|
|
Mutex(const Mutex&);
|
|
Mutex& operator = (const Mutex&);
|
|
|
|
#if defined(HAVE_PTHREADS)
|
|
pthread_mutex_t mMutex;
|
|
#else
|
|
void _init();
|
|
void* mState;
|
|
#endif
|
|
};
|
|
|
|
// ---------------------------------------------------------------------------
|
|
|
|
#if defined(HAVE_PTHREADS)
|
|
|
|
inline Mutex::Mutex() {
|
|
pthread_mutex_init(&mMutex, NULL);
|
|
}
|
|
inline Mutex::Mutex(__attribute__((unused)) const char* name) {
|
|
pthread_mutex_init(&mMutex, NULL);
|
|
}
|
|
inline Mutex::Mutex(int type, __attribute__((unused)) const char* name) {
|
|
if (type == SHARED) {
|
|
pthread_mutexattr_t attr;
|
|
pthread_mutexattr_init(&attr);
|
|
pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
|
|
pthread_mutex_init(&mMutex, &attr);
|
|
pthread_mutexattr_destroy(&attr);
|
|
} else {
|
|
pthread_mutex_init(&mMutex, NULL);
|
|
}
|
|
}
|
|
inline Mutex::~Mutex() {
|
|
pthread_mutex_destroy(&mMutex);
|
|
}
|
|
inline status_t Mutex::lock() {
|
|
return -pthread_mutex_lock(&mMutex);
|
|
}
|
|
inline void Mutex::unlock() {
|
|
pthread_mutex_unlock(&mMutex);
|
|
}
|
|
inline status_t Mutex::tryLock() {
|
|
return -pthread_mutex_trylock(&mMutex);
|
|
}
|
|
#if HAVE_ANDROID_OS
|
|
inline status_t Mutex::timedLock(nsecs_t timeoutNs) {
|
|
const struct timespec ts = {
|
|
/* .tv_sec = */ timeoutNs / 1000000000,
|
|
/* .tv_nsec = */ timeoutNs % 1000000000,
|
|
};
|
|
return -pthread_mutex_timedlock(&mMutex, &ts);
|
|
}
|
|
#endif
|
|
|
|
#endif // HAVE_PTHREADS
|
|
|
|
// ---------------------------------------------------------------------------
|
|
|
|
/*
|
|
* Automatic mutex. Declare one of these at the top of a function.
|
|
* When the function returns, it will go out of scope, and release the
|
|
* mutex.
|
|
*/
|
|
|
|
typedef Mutex::Autolock AutoMutex;
|
|
|
|
// ---------------------------------------------------------------------------
|
|
}; // namespace android
|
|
// ---------------------------------------------------------------------------
|
|
|
|
#endif // _LIBS_UTILS_MUTEX_H
|