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/**
* Copyright (C) 2019-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/util/read_through_cache.h"
#include "mongo/stdx/condition_variable.h"
namespace mongo {
ReadThroughCacheBase::ReadThroughCacheBase(ServiceContext* service, ThreadPoolInterface& threadPool)
: _serviceContext(service), _threadPool(threadPool) {}
ReadThroughCacheBase::~ReadThroughCacheBase() = default;
struct ReadThroughCacheBase::CancelToken::TaskInfo {
TaskInfo(ServiceContext* service, Mutex& cancelTokenMutex)
: service(service), cancelTokenMutex(cancelTokenMutex) {}
ServiceContext* const service;
Mutex& cancelTokenMutex;
Status cancelStatus{Status::OK()};
OperationContext* opCtxToCancel{nullptr};
};
ReadThroughCacheBase::CancelToken::CancelToken(std::shared_ptr<TaskInfo> info)
: _info(std::move(info)) {}
ReadThroughCacheBase::CancelToken::CancelToken(CancelToken&&) = default;
ReadThroughCacheBase::CancelToken::~CancelToken() = default;
void ReadThroughCacheBase::CancelToken::tryCancel() {
stdx::lock_guard lg(_info->cancelTokenMutex);
_info->cancelStatus =
Status(ErrorCodes::ReadThroughCacheLookupCanceled, "Internal only: task canceled");
if (_info->opCtxToCancel) {
stdx::lock_guard clientLock(*_info->opCtxToCancel->getClient());
_info->service->killOperation(clientLock, _info->opCtxToCancel, _info->cancelStatus.code());
}
}
ReadThroughCacheBase::CancelToken ReadThroughCacheBase::_asyncWork(
WorkWithOpContext work) noexcept {
auto taskInfo = std::make_shared<CancelToken::TaskInfo>(_serviceContext, _cancelTokensMutex);
_threadPool.schedule(
[work = std::move(work), taskInfo](Status cancelStatusAtTaskBegin) mutable {
if (!cancelStatusAtTaskBegin.isOK()) {
work(nullptr, cancelStatusAtTaskBegin);
return;
}
ThreadClient tc(taskInfo->service);
// TODO(SERVER-74659): Please revisit if this thread could be made killable.
{
stdx::lock_guard<Client> lk(*tc.get());
tc.get()->setSystemOperationUnkillableByStepdown(lk);
}
auto opCtxHolder = tc->makeOperationContext();
cancelStatusAtTaskBegin = [&] {
stdx::lock_guard lg(taskInfo->cancelTokenMutex);
taskInfo->opCtxToCancel = opCtxHolder.get();
return taskInfo->cancelStatus;
}();
ON_BLOCK_EXIT([&] {
stdx::lock_guard lg(taskInfo->cancelTokenMutex);
taskInfo->opCtxToCancel = nullptr;
});
work(taskInfo->opCtxToCancel, cancelStatusAtTaskBegin);
});
return CancelToken(std::move(taskInfo));
}
Date_t ReadThroughCacheBase::_now() {
return _serviceContext->getFastClockSource()->now();
}
} // namespace mongo
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