1
0
Fork 0
arangodb/arangod/Aql/EnumerateCollectionBlock.h

94 lines
2.8 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS 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 Max Neunhoeffer
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_AQL_ENUMERATE_COLLECTION_BLOCK_H
#define ARANGOD_AQL_ENUMERATE_COLLECTION_BLOCK_H 1
#include "Aql/CollectionScanner.h"
#include "Aql/ExecutionBlock.h"
#include "Aql/ExecutionNode.h"
#include <velocypack/Iterator.h>
#include <velocypack/Slice.h>
struct TRI_doc_mptr_t;
namespace arangodb {
namespace aql {
class AqlItemBlock;
struct Collection;
class CollectionScanner;
class ExecutionEngine;
class EnumerateCollectionBlock : public ExecutionBlock {
public:
EnumerateCollectionBlock(ExecutionEngine* engine,
EnumerateCollectionNode const* ep);
~EnumerateCollectionBlock() = default;
/// @brief initialize fetching of documents
void initializeDocuments();
/// @brief skip instead of fetching
bool skipDocuments(size_t toSkip, size_t& skipped);
/// @brief continue fetching of documents
bool moreDocuments(size_t hint);
/// @brief initialize, here we fetch all docs from the database
int initialize() override final;
/// @brief initializeCursor
int initializeCursor(AqlItemBlock* items, size_t pos) override;
/// @brief getSome
AqlItemBlock* getSome(size_t atLeast, size_t atMost) override final;
// skip between atLeast and atMost, returns the number actually skipped . . .
// will only return less than atLeast if there aren't atLeast many
// things to skip overall.
size_t skipSome(size_t atLeast, size_t atMost) override final;
private:
/// @brief collection
Collection* _collection;
/// @brief collection scanner
CollectionScanner _scanner;
/// @brief iterator over documents
arangodb::velocypack::ArrayIterator _iterator;
/// @brief document buffer
arangodb::velocypack::Slice _documents;
/// @brief whether or not the enumerated documents need to be stored
bool _mustStoreResult;
};
} // namespace arangodb::aql
} // namespace arangodb
#endif