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Diffstat (limited to 'src/mongo/db/s/collection_sharding_runtime_lock.h')
| -rw-r--r-- | src/mongo/db/s/collection_sharding_runtime_lock.h | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/src/mongo/db/s/collection_sharding_runtime_lock.h b/src/mongo/db/s/collection_sharding_runtime_lock.h new file mode 100644 index 00000000000..3105f52157b --- /dev/null +++ b/src/mongo/db/s/collection_sharding_runtime_lock.h @@ -0,0 +1,82 @@ +/** + * 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. + */ + +#pragma once + +#include "mongo/base/disallow_copying.h" +#include "mongo/db/concurrency/d_concurrency.h" +#include "mongo/stdx/variant.h" + +namespace mongo { + +class CollectionShardingState; + +/** + * RAII-style class that locks the CollectionShardingRuntime using the CollectionShardingRuntime's + * ResourceMutex. The lock will be created and acquired on construction. The lock will be dismissed + * upon destruction of the CollectionShardingRuntimeLock object. + * + * The CollectionShardingRuntimeLock currently ensures concurrent access to the following sections: + * + * - The collection's critical section + * - Attaching and detaching the MigrationSoourceManager from the CollectionShardingRuntime and + * accessing the MigrationSourceManager from the CollectionShardingRuntime. + */ +class CollectionShardingRuntimeLock { + +public: + using CSRLock = stdx::variant<Lock::SharedLock, Lock::ExclusiveLock>; + + /** + * Locks the sharding runtime state for the specified collection with the + * CollectionShardingRuntime object's ResourceMutex in MODE_IS. When the object goes out of + * scope, the ResourceMutex will be unlocked. + */ + static CollectionShardingRuntimeLock lock(OperationContext* opCtx, + CollectionShardingState* csr); + + /** + * Follows the same functionality as the CollectionShardingRuntimeLock lock method, except + * that lockExclusive takes the ResourceMutex in MODE_X. + */ + static CollectionShardingRuntimeLock lockExclusive(OperationContext* opCtx, + CollectionShardingState* csr); + +private: + CollectionShardingRuntimeLock(OperationContext* opCtx, + CollectionShardingState* csr, + LockMode lockMode); + + // The lock created and locked upon construction of a CollectionShardingRuntimeLock object. + // It locks the ResourceMutex taken from the CollectionShardingRuntime class, passed in on + // construction. + CSRLock _lock; +}; + +} // namespace mongo
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