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/**
* Copyright (C) 2018-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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kQuery
#include "mongo/platform/basic.h"
#include "mongo/executor/async_multicaster.h"
#include <memory>
#include "mongo/base/status.h"
#include "mongo/db/operation_context.h"
#include "mongo/platform/mutex.h"
#include "mongo/stdx/condition_variable.h"
#include "mongo/util/assert_util.h"
namespace mongo {
namespace executor {
AsyncMulticaster::AsyncMulticaster(std::shared_ptr<executor::TaskExecutor> executor,
Options options)
: _options(options), _executor(std::move(executor)) {}
std::vector<AsyncMulticaster::Reply> AsyncMulticaster::multicast(
const std::vector<HostAndPort> servers,
const std::string& theDbName,
const BSONObj& theCmdObj,
OperationContext* opCtx,
Milliseconds timeoutMillis) {
// Everything goes into a state struct because we can get cancelled, and then our callback would
// be invoked later.
struct State {
State(size_t leftToDo) : leftToDo(leftToDo) {}
Mutex mutex = MONGO_MAKE_LATCH("State::mutex");
stdx::condition_variable cv;
size_t leftToDo;
size_t running = 0;
// To indicate which hosts fail.
std::vector<Reply> out;
};
auto state = std::make_shared<State>(servers.size());
for (const auto& server : servers) {
stdx::unique_lock<Latch> lk(state->mutex);
// spin up no more than maxConcurrency tasks at once
opCtx->waitForConditionOrInterrupt(
state->cv, lk, [&] { return state->running < _options.maxConcurrency; });
++state->running;
uassertStatusOK(_executor->scheduleRemoteCommand(
RemoteCommandRequest{server, theDbName, theCmdObj, opCtx, timeoutMillis},
[state](const TaskExecutor::RemoteCommandCallbackArgs& cbData) {
stdx::lock_guard<Latch> lk(state->mutex);
state->out.emplace_back(
std::forward_as_tuple(cbData.request.target, cbData.response));
// If we were the last job, flush the done flag and release via notify.
if (!--(state->leftToDo)) {
state->cv.notify_one();
}
if (--(state->running) < kMaxConcurrency) {
state->cv.notify_one();
}
}));
}
stdx::unique_lock<Latch> lk(state->mutex);
opCtx->waitForConditionOrInterrupt(state->cv, lk, [&] { return state->leftToDo == 0; });
return std::move(state->out);
}
} // namespace executor
} // namespace mongo
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