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/**
* Copyright (C) 2014 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.
*/
#pragma once
#include <boost/scoped_ptr.hpp>
#include "mongo/base/disallow_copying.h"
#include "mongo/bson/optime.h"
#include "mongo/util/time_support.h"
namespace mongo {
class BSONObj;
class OID;
class OperationContext;
class Status;
struct HostAndPort;
template <typename T> class StatusWith;
namespace repl {
/**
* This class represents the interface the ReplicationCoordinator uses to interact with the
* rest of the system. All functionality of the ReplicationCoordinatorImpl that would introduce
* dependencies on large sections of the server code and thus break the unit testability of
* ReplicationCoordinatorImpl should be moved here.
*/
class ReplicationCoordinatorExternalState {
MONGO_DISALLOW_COPYING(ReplicationCoordinatorExternalState);
public:
class GlobalSharedLockAcquirer;
class ScopedLocker;
ReplicationCoordinatorExternalState();
virtual ~ReplicationCoordinatorExternalState();
/**
* Simple wrapper around SyncSourceFeedback::run(). Loops continuously until shutdown() is
* called.
*/
virtual void runSyncSourceFeedback() = 0;
/**
* Performs any necessary external state specific shutdown tasks, such as signaling
* the SyncSourceFeedback thread to terminate.
*/
virtual void shutdown() = 0;
/**
* Simple wrapper around SyncSourceFeedback::forwardSlaveHandshake. Signals to the
* SyncSourceFeedback thread that it needs to wake up and send a replication handshake
* upstream.
*/
virtual void forwardSlaveHandshake() = 0;
/**
* Simple wrapper around SyncSourceFeedback::forwardSlaveProgress. Signals to the
* SyncSourceFeedback thread that it needs to wake up and send a replSetUpdatePosition
* command upstream.
*/
virtual void forwardSlaveProgress() = 0;
/**
* Queries the singleton document in local.me. If it exists and our hostname has not
* changed since we wrote, returns the RID stored in the object. If the document does not
* exist or our hostname doesn't match what was recorded in local.me, generates a new OID
* to use as our RID, stores it in local.me, and returns it.
*/
virtual OID ensureMe(OperationContext*) = 0;
/**
* Returns true if "host" is one of the network identities of this node.
*/
virtual bool isSelf(const HostAndPort& host) = 0;
/**
* Gets the replica set config document from local storage, or returns an error.
*/
virtual StatusWith<BSONObj> loadLocalConfigDocument(OperationContext* txn) = 0;
/**
* Stores the replica set config document in local storage, or returns an error.
*/
virtual Status storeLocalConfigDocument(OperationContext* txn, const BSONObj& config) = 0;
/**
* Gets the last optime of an operation performed on this host, from stable
* storage.
*/
virtual StatusWith<OpTime> loadLastOpTime(OperationContext* txn) = 0;
/**
* Returns the HostAndPort of the remote client connected to us that initiated the operation
* represented by "txn".
*/
virtual HostAndPort getClientHostAndPort(const OperationContext* txn) = 0;
/**
* Closes all client connections.
* This is used during stepdown, and transition out of primary.
*/
virtual void closeClientConnections() = 0;
/**
* Returns an instance of GlobalSharedLockAcquirer that can be used to acquire the global
* shared lock.
*/
virtual GlobalSharedLockAcquirer* getGlobalSharedLockAcquirer() = 0;
/**
* Returns an OperationContext, owned by the caller, that may be used in methods of
* the same instance that require an OperationContext.
*/
virtual OperationContext* createOperationContext() = 0;
};
/**
* Interface that encapsulates acquiring the global shared lock.
*/
class ReplicationCoordinatorExternalState::GlobalSharedLockAcquirer {
public:
virtual ~GlobalSharedLockAcquirer();
virtual bool try_lock(OperationContext* txn, const Milliseconds& timeout) = 0;
};
/**
* Class used to acquire the global shared lock, using a given implementation of
* GlobalSharedLockAcquirer.
*/
class ReplicationCoordinatorExternalState::ScopedLocker {
public:
/**
* Takes ownership of the passed in GlobalSharedLockAcquirer.
*/
ScopedLocker(OperationContext* txn,
GlobalSharedLockAcquirer* locker,
const Milliseconds& timeout);
~ScopedLocker();
bool gotLock() const;
private:
boost::scoped_ptr<ReplicationCoordinatorExternalState::GlobalSharedLockAcquirer> _locker;
bool _gotLock;
};
} // namespace repl
} // namespace mongo
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