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arangodb/arangod/Graph/TraverserDocumentCache.h

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////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2017-2017 ArangoDB GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Michael Hackstein
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_GRAPH_TRAVERSER_DOCUMENT_CACHE_H
#define ARANGOD_GRAPH_TRAVERSER_DOCUMENT_CACHE_H 1
#include "Graph/TraverserCache.h"
namespace arangodb {
namespace cache {
class Cache;
class Finding;
}
namespace graph {
class TraverserDocumentCache : public TraverserCache {
public:
explicit TraverserDocumentCache(transaction::Methods* trx);
~TraverserDocumentCache();
//////////////////////////////////////////////////////////////////////////////
/// @brief Inserts the real document stored within the token
/// into the given builder.
/// The document will be taken from the hash-cache.
/// If it is not cached it will be looked up in the StorageEngine
//////////////////////////////////////////////////////////////////////////////
void insertIntoResult(StringRef idString,
arangodb::velocypack::Builder& builder) override;
void insertIntoResult(EdgeDocumentToken const* etkn,
arangodb::velocypack::Builder& builder) override;
//////////////////////////////////////////////////////////////////////////////
/// @brief Return AQL value containing the result
/// The document will be taken from the hash-cache.
/// If it is not cached it will be looked up in the StorageEngine
//////////////////////////////////////////////////////////////////////////////
aql::AqlValue fetchAqlResult(StringRef idString) override;
aql::AqlValue fetchAqlResult(arangodb::graph::EdgeDocumentToken const*) override;
//////////////////////////////////////////////////////////////////////////////
/// @brief Insert value into store
//////////////////////////////////////////////////////////////////////////////
void insertDocument(StringRef idString,
arangodb::velocypack::Slice const& document) override;
//////////////////////////////////////////////////////////////////////////////
/// @brief Throws the document referenced by the token into the filter
/// function and returns it result.
/// The document will be taken from the hash-cache.
/// If it is not cached it will be looked up in the StorageEngine
//////////////////////////////////////////////////////////////////////////////
bool validateFilter(StringRef idString,
std::function<bool(arangodb::velocypack::Slice const&)> filterFunc) override;
protected:
//////////////////////////////////////////////////////////////////////////////
/// @brief Lookup a document by token in the cache.
/// As long as finding is retained it is guaranteed that the result
/// stays valid. Finding should not be retained very long, if it is
/// needed for longer, copy the value.
//////////////////////////////////////////////////////////////////////////////
cache::Finding lookup(StringRef idString);
protected:
//////////////////////////////////////////////////////////////////////////////
/// @brief The hash-cache that saves documents found in the Database
//////////////////////////////////////////////////////////////////////////////
std::shared_ptr<arangodb::cache::Cache> _cache;
//////////////////////////////////////////////////////////////////////////////
/// @brief Lookup a document from the database and insert it into the cache.
/// The Slice returned here is only valid until the NEXT call of this
/// function.
//////////////////////////////////////////////////////////////////////////////
arangodb::velocypack::Slice lookupAndCache(
StringRef idString);
};
} // namespace traverser
} // namespace arangodb
#endif