5e94f68f35
Summary: Prototype of API to allow MyRocks to override default Mutex/CondVar used by transactions with their own implementations. They would simply need to pass their own implementations of Mutex/CondVar to the templated TransactionDB::Open(). Default implementation of TransactionDBMutex/TransactionDBCondVar provided (but the code is not currently changed to use this). Let me know if this API makes sense or if it should be changed Test Plan: n/a Reviewers: yhchiang, rven, igor, sdong, spetrunia Reviewed By: spetrunia Subscribers: maykov, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D43761
122 lines
3.3 KiB
C++
122 lines
3.3 KiB
C++
// Copyright (c) 2015, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#ifndef ROCKSDB_LITE
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#include "utilities/transactions/transaction_db_mutex_impl.h"
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#include <chrono>
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#include <condition_variable>
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#include <functional>
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#include <mutex>
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#include "rocksdb/utilities/transaction_db_mutex.h"
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namespace rocksdb {
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class TransactionDBMutexImpl : public TransactionDBMutex {
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public:
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TransactionDBMutexImpl() {}
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~TransactionDBMutexImpl() {}
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Status Lock() override;
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Status TryLockFor(int64_t timeout_time) override;
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void UnLock() override { mutex_.unlock(); }
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friend class TransactionDBCondVarImpl;
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private:
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std::timed_mutex mutex_;
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};
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class TransactionDBCondVarImpl : public TransactionDBCondVar {
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public:
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TransactionDBCondVarImpl() {}
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~TransactionDBCondVarImpl() {}
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Status Wait(std::shared_ptr<TransactionDBMutex> mutex) override;
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Status WaitFor(std::shared_ptr<TransactionDBMutex> mutex,
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int64_t timeout_time) override;
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void Notify() override { cv_.notify_one(); }
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void NotifyAll() override { cv_.notify_all(); }
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private:
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std::condition_variable_any cv_;
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};
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std::shared_ptr<TransactionDBMutex>
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TransactionDBMutexFactoryImpl::AllocateMutex() {
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return std::shared_ptr<TransactionDBMutex>(new TransactionDBMutexImpl());
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}
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std::shared_ptr<TransactionDBCondVar>
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TransactionDBMutexFactoryImpl::AllocateCondVar() {
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return std::shared_ptr<TransactionDBCondVar>(new TransactionDBCondVarImpl());
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}
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Status TransactionDBMutexImpl::Lock() {
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mutex_.lock();
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return Status::OK();
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}
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Status TransactionDBMutexImpl::TryLockFor(int64_t timeout_time) {
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bool locked = true;
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if (timeout_time < 0) {
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// If timeout is negative, we wait indefinitely to acquire the lock
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mutex_.lock();
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} else if (timeout_time == 0) {
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locked = mutex_.try_lock();
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} else {
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// Attempt to acquire the lock unless we timeout
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auto duration = std::chrono::microseconds(timeout_time);
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locked = mutex_.try_lock_for(duration);
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}
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if (!locked) {
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// timeout acquiring mutex
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return Status::TimedOut(Status::SubCode::kMutexTimeout);
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}
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return Status::OK();
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}
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Status TransactionDBCondVarImpl::Wait(
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std::shared_ptr<TransactionDBMutex> mutex) {
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auto mutex_impl = reinterpret_cast<TransactionDBMutexImpl*>(mutex.get());
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cv_.wait(mutex_impl->mutex_);
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return Status::OK();
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}
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Status TransactionDBCondVarImpl::WaitFor(
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std::shared_ptr<TransactionDBMutex> mutex, int64_t timeout_time) {
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auto mutex_impl = reinterpret_cast<TransactionDBMutexImpl*>(mutex.get());
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if (timeout_time < 0) {
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// If timeout is negative, do not use a timeout
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cv_.wait(mutex_impl->mutex_);
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} else {
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auto duration = std::chrono::microseconds(timeout_time);
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auto cv_status = cv_.wait_for(mutex_impl->mutex_, duration);
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// Check if the wait stopped due to timing out.
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if (cv_status == std::cv_status::timeout) {
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return Status::TimedOut(Status::SubCode::kMutexTimeout);
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}
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}
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// CV was signaled, or we spuriously woke up (but didn't time out)
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return Status::OK();
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}
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} // namespace rocksdb
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#endif // ROCKSDB_LITE
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