mirror of https://gitee.com/bigwinds/arangodb
132 lines
4.1 KiB
C++
132 lines
4.1 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2014-2018 ArangoDB GmbH, Cologne, Germany
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/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is ArangoDB GmbH, Cologne, Germany
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///
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/// @author Jan Steemann
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/// @author Simon Grätzer
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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGOD_AQL_QUERY_CURSOR_H
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#define ARANGOD_AQL_QUERY_CURSOR_H 1
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#include "Aql/QueryResult.h"
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#include "Basics/Common.h"
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#include "Utils/Cursor.h"
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#include "VocBase/vocbase.h"
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namespace arangodb {
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namespace aql {
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class AqlItemBlock;
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enum class ExecutionState;
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class Query;
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/// Cursor managing an entire query result in-memory
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/// Should be used in conjunction with the RestCursorHandler
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class QueryResultCursor final : public arangodb::Cursor {
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public:
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QueryResultCursor(TRI_vocbase_t& vocbase, CursorId id,
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aql::QueryResult&& result, size_t batchSize, double ttl,
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bool hasCount);
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~QueryResultCursor() = default;
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aql::QueryResult const* result() const { return &_result; }
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CursorType type() const override final { return CURSOR_VPACK; }
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bool hasNext();
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arangodb::velocypack::Slice next();
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size_t count() const override final;
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std::pair<ExecutionState, Result> dump(
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velocypack::Builder& result,
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std::function<void()> const& continueHandler) override final;
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Result dumpSync(velocypack::Builder& result) override final;
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std::shared_ptr<transaction::Context> context() const override final {
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return _result.context;
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}
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/// @brief Returns a slice to read the extra values.
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/// Make sure the Cursor Object is not destroyed while reading this slice.
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/// If no extras are set this will return a NONE slice.
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arangodb::velocypack::Slice extra() const;
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private:
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DatabaseGuard _guard;
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aql::QueryResult _result;
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arangodb::velocypack::ArrayIterator _iterator;
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bool _cached;
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};
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/// Cursor managing a query from which it continuously gets
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/// new results. Query, transaction and locks will live until
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/// cursor is deleted (or query exhausted)
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class QueryStreamCursor final : public arangodb::Cursor {
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public:
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QueryStreamCursor(TRI_vocbase_t& vocbase, CursorId id,
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std::string const& query,
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std::shared_ptr<velocypack::Builder> bindVars,
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std::shared_ptr<velocypack::Builder> opts, size_t batchSize,
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double ttl);
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~QueryStreamCursor();
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CursorType type() const override final { return CURSOR_VPACK; }
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size_t count() const override final { return 0; }
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// TODO add this to Cursor and make it virtual / override final.
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ExecutionState prepareDump();
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std::pair<ExecutionState, Result> dump(
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velocypack::Builder& result,
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std::function<void()> const& continueHandler) override final;
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Result dumpSync(velocypack::Builder& result) override final;
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std::shared_ptr<transaction::Context> context() const override final;
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private:
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// Writes from _queryResults to builder. Removes copied blocks from _queryResults and sets _queryResultPos
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// appropriately.
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// Relies on the caller to have fetched more than batchSize() result rows
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// (if possible) in order to set hasMore reliably.
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Result writeResult(velocypack::Builder &builder);
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private:
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DatabaseGuard _guard;
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int64_t _exportCount; // used by RocksDBRestExportHandler
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std::unique_ptr<aql::Query> _query;
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std::deque<std::unique_ptr<AqlItemBlock>> _queryResults;
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// index of the next to-be-returned row in _queryResults.front()
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size_t _queryResultPos;
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};
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} // aql
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} // arangodb
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#endif
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