562f64f292
Updates to OEMCrypto API, OPK, ODK, and unit tests. See the file CHANGELOG.md for details.
66 lines
1.7 KiB
C++
66 lines
1.7 KiB
C++
// Copyright 2019 Google LLC. All Rights Reserved. This file and proprietary
|
|
// source code may only be used and distributed under the Widevine License
|
|
// Agreement.
|
|
|
|
#ifndef WVCDM_UTIL_RW_LOCK_H_
|
|
#define WVCDM_UTIL_RW_LOCK_H_
|
|
|
|
#include <stdint.h>
|
|
|
|
#include <condition_variable>
|
|
#include <mutex>
|
|
|
|
#include "disallow_copy_and_assign.h"
|
|
#include "util_common.h"
|
|
|
|
namespace wvutil {
|
|
|
|
// A simple reader-writer mutex implementation that mimics the one from C++17
|
|
class shared_mutex {
|
|
public:
|
|
shared_mutex() : reader_count_(0), has_writer_(false) {}
|
|
~shared_mutex();
|
|
|
|
// These methods take the mutex as a reader. They do not fulfill the
|
|
// SharedMutex requirement from the C++14 STL, but they fulfill enough of it
|
|
// to be used with |shared_lock| below.
|
|
void lock_shared();
|
|
void unlock_shared();
|
|
|
|
// These methods take the mutex as a writer. They fulfill the Mutex
|
|
// requirement from the C++11 STL so that this mutex can be used with
|
|
// |std::unique_lock|.
|
|
void lock() { lock_implementation(false); }
|
|
bool try_lock() { return lock_implementation(true); }
|
|
void unlock();
|
|
|
|
private:
|
|
bool lock_implementation(bool abort_if_unavailable);
|
|
|
|
uint32_t reader_count_;
|
|
bool has_writer_;
|
|
|
|
std::mutex mutex_;
|
|
std::condition_variable condition_variable_;
|
|
|
|
CORE_DISALLOW_COPY_AND_ASSIGN(shared_mutex);
|
|
};
|
|
|
|
// A simple reader lock implementation that mimics the one from C++14
|
|
template <typename Mutex>
|
|
class shared_lock {
|
|
public:
|
|
explicit shared_lock(Mutex& lock) : lock_(&lock) { lock_->lock_shared(); }
|
|
explicit shared_lock(Mutex* lock) : lock_(lock) { lock_->lock_shared(); }
|
|
~shared_lock() { lock_->unlock_shared(); }
|
|
|
|
private:
|
|
Mutex* lock_;
|
|
|
|
CORE_DISALLOW_COPY_AND_ASSIGN(shared_lock);
|
|
};
|
|
|
|
} // namespace wvutil
|
|
|
|
#endif // WVCDM_UTIL_RW_LOCK_H_
|