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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.
*/
#pragma once
#include <unordered_map>
#include "mongo/base/disallow_copying.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/op_observer.h"
#include "mongo/db/service_context.h"
#include "mongo/stdx/functional.h"
#include "mongo/util/uuid.h"
namespace mongo {
/**
* Class used for updating the UUID catalog on metadata operations.
*/
class UUIDCatalogObserver : public OpObserver {
public:
void onCreateIndex(OperationContext* opCtx,
const NamespaceString& nss,
CollectionUUID uuid,
BSONObj indexDoc,
bool fromMigrate) override {}
void onInserts(OperationContext* opCtx,
const NamespaceString& nss,
OptionalCollectionUUID uuid,
std::vector<InsertStatement>::const_iterator begin,
std::vector<InsertStatement>::const_iterator end,
bool fromMigrate) override {}
void onUpdate(OperationContext* opCtx, const OplogUpdateEntryArgs& args) override {}
void aboutToDelete(OperationContext* opCtx,
const NamespaceString& nss,
const BSONObj& doc) override {}
void onDelete(OperationContext* opCtx,
const NamespaceString& nss,
OptionalCollectionUUID uuid,
StmtId stmtId,
bool fromMigrate,
const boost::optional<BSONObj>& deletedDoc) override {}
void onInternalOpMessage(OperationContext* opCtx,
const NamespaceString& nss,
const boost::optional<UUID> uuid,
const BSONObj& msgObj,
const boost::optional<BSONObj> o2MsgObj) override {}
void onCreateCollection(OperationContext* opCtx,
Collection* coll,
const NamespaceString& collectionName,
const CollectionOptions& options,
const BSONObj& idIndex,
const OplogSlot& createOpTime) override;
void onCollMod(OperationContext* opCtx,
const NamespaceString& nss,
OptionalCollectionUUID uuid,
const BSONObj& collModCmd,
const CollectionOptions& oldCollOptions,
boost::optional<TTLCollModInfo> ttlInfo) override;
void onDropDatabase(OperationContext* opCtx, const std::string& dbName) override {}
repl::OpTime onDropCollection(OperationContext* opCtx,
const NamespaceString& collectionName,
OptionalCollectionUUID uuid,
CollectionDropType dropType) override;
void onDropIndex(OperationContext* opCtx,
const NamespaceString& nss,
OptionalCollectionUUID uuid,
const std::string& indexName,
const BSONObj& idxDescriptor) override {}
void onRenameCollection(OperationContext* opCtx,
const NamespaceString& fromCollection,
const NamespaceString& toCollection,
OptionalCollectionUUID uuid,
OptionalCollectionUUID dropTargetUUID,
bool stayTemp) override;
repl::OpTime preRenameCollection(OperationContext* opCtx,
const NamespaceString& fromCollection,
const NamespaceString& toCollection,
OptionalCollectionUUID uuid,
OptionalCollectionUUID dropTargetUUID,
bool stayTemp) override;
void postRenameCollection(OperationContext* opCtx,
const NamespaceString& fromCollection,
const NamespaceString& toCollection,
OptionalCollectionUUID uuid,
OptionalCollectionUUID dropTargetUUID,
bool stayTemp) override;
void onApplyOps(OperationContext* opCtx,
const std::string& dbName,
const BSONObj& applyOpCmd) override {}
void onEmptyCapped(OperationContext* opCtx,
const NamespaceString& collectionName,
OptionalCollectionUUID uuid) override {}
void onTransactionCommit(OperationContext* opCtx,
boost::optional<OplogSlot> commitOplogEntryOpTime,
boost::optional<Timestamp> commitTimestamp) override {}
void onTransactionPrepare(OperationContext* opCtx, const OplogSlot& prepareOpTime) override {}
void onTransactionAbort(OperationContext* opCtx,
boost::optional<OplogSlot> abortOplogEntryOpTime) override {}
void onReplicationRollback(OperationContext* opCtx,
const RollbackObserverInfo& rbInfo) override {}
};
/**
* This class comprises a UUID to collection catalog, allowing for efficient
* collection lookup by UUID.
*/
using CollectionUUID = UUID;
class Database;
class UUIDCatalog {
MONGO_DISALLOW_COPYING(UUIDCatalog);
public:
static UUIDCatalog& get(ServiceContext* svcCtx);
static UUIDCatalog& get(OperationContext* opCtx);
UUIDCatalog() = default;
/**
* This function inserts the entry for uuid, coll into the UUID Collection. It is called by
* the op observer when a collection is created.
*/
void onCreateCollection(OperationContext* opCtx, Collection* coll, CollectionUUID uuid);
/**
* This function removes the entry for uuid from the UUID catalog. It is called by the op
* observer when a collection is dropped.
*/
void onDropCollection(OperationContext* opCtx, CollectionUUID uuid);
/**
* This function atomically removes any existing entry for uuid from the UUID catalog and adds
* a new entry for uuid associated with the Collection coll. It is called by the op observer
* when a collection is renamed.
*/
void onRenameCollection(OperationContext* opCtx, Collection* coll, CollectionUUID uuid);
/**
* Implies onDropCollection for all collections in db, but is not transactional.
*/
void onCloseDatabase(Database* db);
Collection* replaceUUIDCatalogEntry(CollectionUUID uuid, Collection* coll);
void registerUUIDCatalogEntry(CollectionUUID uuid, Collection* coll);
Collection* removeUUIDCatalogEntry(CollectionUUID uuid);
/**
* This function gets the Collection pointer that corresponds to the CollectionUUID. The
* required locks should be obtained prior to calling this function, or else the found
* Collection pointer might no longer be valid when the call returns.
*
* Returns nullptr if the 'uuid' is not known.
*/
Collection* lookupCollectionByUUID(CollectionUUID uuid) const;
/**
* This function gets the NamespaceString from the Collection* pointer that
* corresponds to CollectionUUID uuid. If there is no such pointer, an empty
* NamespaceString is returned. See onCloseCatalog/onOpenCatalog for more info.
*/
NamespaceString lookupNSSByUUID(CollectionUUID uuid) const;
/**
* Puts the catalog in closed state. In this state, the lookupNSSByUUID method will fall back
* to the pre-close state to resolve queries for currently unknown UUIDs. This allows processes,
* like authorization and replication, which need to do lookups outside of database locks, to
* proceed.
*
* Must be called with the global lock acquired in exclusive mode.
*/
void onCloseCatalog(OperationContext* opCtx);
/**
* Puts the catatlog back in open state, removing the pre-close state. See onCloseCatalog.
*
* Must be called with the global lock acquired in exclusive mode.
*/
void onOpenCatalog(OperationContext* opCtx);
/**
* Return the UUID lexicographically preceding `uuid` in the database named by `db`.
*
* Return `boost::none` if `uuid` is not found, or is the first UUID in that database.
*/
boost::optional<CollectionUUID> prev(const StringData& db, CollectionUUID uuid);
/**
* Return the UUID lexicographically following `uuid` in the database named by `db`.
*
* Return `boost::none` if `uuid` is not found, or is the last UUID in that database.
*/
boost::optional<CollectionUUID> next(const StringData& db, CollectionUUID uuid);
private:
const std::vector<CollectionUUID>& _getOrdering_inlock(const StringData& db,
const stdx::lock_guard<stdx::mutex>&);
void _registerUUIDCatalogEntry_inlock(CollectionUUID uuid, Collection* coll);
Collection* _removeUUIDCatalogEntry_inlock(CollectionUUID uuid);
mutable mongo::stdx::mutex _catalogLock;
/**
* When present, indicates that the catalog is in closed state, and contains a map from UUID
* to pre-close NSS. See also onCloseCatalog.
*/
boost::optional<
mongo::stdx::unordered_map<CollectionUUID, NamespaceString, CollectionUUID::Hash>>
_shadowCatalog;
/**
* Map from database names to ordered `vector`s of their UUIDs.
*
* Works as a cache of such orderings: every ordering in this map is guaranteed to be valid, but
* not all databases are guaranteed to have an ordering in it.
*/
StringMap<std::vector<CollectionUUID>> _orderedCollections;
mongo::stdx::unordered_map<CollectionUUID, Collection*, CollectionUUID::Hash> _catalog;
};
} // namespace mongo
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