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/**
* Copyright (C) 2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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/platform/basic.h"
#include "mongo/db/repl/multiapplier.h"
#include <utility>
#include "mongo/db/client.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/repl/optime.h"
#include "mongo/util/destructor_guard.h"
namespace mongo {
namespace repl {
MultiApplier::MultiApplier(executor::TaskExecutor* executor,
const Operations& operations,
const MultiApplyFn& multiApply,
const CallbackFn& onCompletion)
: _executor(executor),
_operations(operations),
_multiApply(multiApply),
_onCompletion(onCompletion) {
uassert(ErrorCodes::BadValue, "null replication executor", executor);
uassert(ErrorCodes::BadValue, "empty list of operations", !operations.empty());
uassert(ErrorCodes::BadValue, "multi apply function cannot be null", multiApply);
uassert(ErrorCodes::BadValue, "callback function cannot be null", onCompletion);
}
MultiApplier::~MultiApplier() {
DESTRUCTOR_GUARD(shutdown(); join(););
}
bool MultiApplier::isActive() const {
stdx::lock_guard<stdx::mutex> lk(_mutex);
return _isActive_inlock();
}
bool MultiApplier::_isActive_inlock() const {
return State::kRunning == _state || State::kShuttingDown == _state;
}
Status MultiApplier::startup() noexcept {
stdx::lock_guard<stdx::mutex> lk(_mutex);
switch (_state) {
case State::kPreStart:
_state = State::kRunning;
break;
case State::kRunning:
return Status(ErrorCodes::InternalError, "multi applier already started");
case State::kShuttingDown:
return Status(ErrorCodes::ShutdownInProgress, "multi applier shutting down");
case State::kComplete:
return Status(ErrorCodes::ShutdownInProgress, "multi applier completed");
}
auto scheduleResult = _executor->scheduleWork(
[=](const executor::TaskExecutor::CallbackArgs& cbd) { return _callback(cbd); });
if (!scheduleResult.isOK()) {
_state = State::kComplete;
return scheduleResult.getStatus();
}
_dbWorkCallbackHandle = scheduleResult.getValue();
return Status::OK();
}
void MultiApplier::shutdown() {
stdx::lock_guard<stdx::mutex> lk(_mutex);
switch (_state) {
case State::kPreStart:
// Transition directly from PreStart to Complete if not started yet.
_state = State::kComplete;
return;
case State::kRunning:
_state = State::kShuttingDown;
break;
case State::kShuttingDown:
case State::kComplete:
// Nothing to do if we are already in ShuttingDown or Complete state.
return;
}
if (_dbWorkCallbackHandle.isValid()) {
_executor->cancel(_dbWorkCallbackHandle);
}
}
void MultiApplier::join() {
stdx::unique_lock<stdx::mutex> lk(_mutex);
_condition.wait(lk, [this]() { return !_isActive_inlock(); });
}
MultiApplier::State MultiApplier::getState_forTest() const {
stdx::lock_guard<stdx::mutex> lk(_mutex);
return _state;
}
void MultiApplier::_callback(const executor::TaskExecutor::CallbackArgs& cbd) {
if (!cbd.status.isOK()) {
_finishCallback(cbd.status);
return;
}
invariant(!_operations.empty());
StatusWith<OpTime> applyStatus(ErrorCodes::InternalError, "not mutated");
try {
auto opCtx = cc().makeOperationContext();
applyStatus = _multiApply(opCtx.get(), _operations);
} catch (...) {
applyStatus = exceptionToStatus();
}
_finishCallback(applyStatus.getStatus());
}
void MultiApplier::_finishCallback(const Status& result) {
// After running callback function, clear '_onCompletion' to release any resources that might be
// held by this function object.
// '_onCompletion' must be moved to a temporary copy and destroyed outside the lock in case
// there is any logic that's invoked at the function object's destruction that might call into
// this MultiApplier. 'onCompletion' must be declared before lock guard 'lock' so that it is
// destroyed outside the lock.
decltype(_onCompletion) onCompletion;
{
stdx::lock_guard<stdx::mutex> lock(_mutex);
invariant(_onCompletion);
std::swap(_onCompletion, onCompletion);
}
onCompletion(result);
stdx::lock_guard<stdx::mutex> lk(_mutex);
invariant(State::kComplete != _state);
_state = State::kComplete;
_condition.notify_all();
}
std::ostream& operator<<(std::ostream& os, const MultiApplier::State& state) {
switch (state) {
case MultiApplier::State::kPreStart:
return os << "PreStart";
case MultiApplier::State::kRunning:
return os << "Running";
case MultiApplier::State::kShuttingDown:
return os << "ShuttingDown";
case MultiApplier::State::kComplete:
return os << "Complete";
}
MONGO_UNREACHABLE;
}
} // namespace repl
} // namespace mongo
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