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arangodb/arangod/Scheduler/JobGuard.h

104 lines
2.6 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2016 ArangoDB GmbH, Cologne, Germany
///
/// 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.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Dr. Frank Celler
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_SCHEDULER_JOB_GUARD_H
#define ARANGOD_SCHEDULER_JOB_GUARD_H 1
#include "Basics/Common.h"
#include "Basics/SameThreadAsserter.h"
#include "Scheduler/EventLoop.h"
#include "Scheduler/Scheduler.h"
namespace arangodb {
namespace rest {
class Scheduler;
}
class JobGuard : public SameThreadAsserter {
public:
JobGuard(JobGuard const&) = delete;
JobGuard& operator=(JobGuard const&) = delete;
explicit JobGuard(EventLoop const& loop) : SameThreadAsserter(), _scheduler(loop.scheduler) {}
explicit JobGuard(rest::Scheduler* scheduler) : SameThreadAsserter(), _scheduler(scheduler) {}
~JobGuard() { release(); }
public:
void work() {
TRI_ASSERT(!_isWorkingFlag);
if (0 == _isWorking++) {
_scheduler->workThread();
}
_isWorkingFlag = true;
}
void block() {
TRI_ASSERT(!_isBlockedFlag);
if (0 == _isBlocked++) {
_scheduler->blockThread();
}
_isBlockedFlag = true;
}
private:
void release() {
if (_isWorkingFlag) {
_isWorkingFlag = false;
TRI_ASSERT(_isWorking > 0);
if (0 == --_isWorking) {
// if this is the last JobGuard we inform the
// scheduler that the thread is back to idle
_scheduler->unworkThread();
}
}
if (_isBlockedFlag) {
_isBlockedFlag = false;
TRI_ASSERT(_isBlocked > 0);
if (0 == --_isBlocked) {
// if this is the last JobGuard we inform the
// scheduler that the thread is now unblocked
_scheduler->unblockThread();
}
}
}
private:
rest::Scheduler* _scheduler;
bool _isWorkingFlag = false;
bool _isBlockedFlag = false;
static thread_local size_t _isWorking;
static thread_local size_t _isBlocked;
};
}
#endif