mirror of https://gitee.com/bigwinds/arangodb
145 lines
3.5 KiB
C++
145 lines
3.5 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2014-2016 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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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGOD_UTILS_CURSOR_H
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#define ARANGOD_UTILS_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/DatabaseGuard.h"
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#include "VocBase/voc-types.h"
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#include <velocypack/Iterator.h>
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namespace arangodb {
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namespace velocypack {
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class Builder;
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class Slice;
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}
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typedef TRI_voc_tick_t CursorId;
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class Cursor {
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public:
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enum CursorType {
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CURSOR_VPACK,
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CURSOR_EXPORT
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};
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Cursor(Cursor const&) = delete;
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Cursor& operator=(Cursor const&) = delete;
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Cursor(CursorId, size_t, std::shared_ptr<arangodb::velocypack::Builder>,
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double, bool);
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virtual ~Cursor();
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public:
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CursorId id() const { return _id; }
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size_t batchSize() const { return _batchSize; }
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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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bool hasCount() const { return _hasCount; }
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double ttl() const { return _ttl; }
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double expires() const { return _expires; }
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bool isUsed() const { return _isUsed; }
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bool isDeleted() const { return _isDeleted; }
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void deleted() { _isDeleted = true; }
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void use() {
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TRI_ASSERT(!_isDeleted);
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TRI_ASSERT(!_isUsed);
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_isUsed = true;
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_expires = TRI_microtime() + _ttl;
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}
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void release() {
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TRI_ASSERT(_isUsed);
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_isUsed = false;
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}
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virtual CursorType type() const = 0;
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virtual bool hasNext() = 0;
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virtual arangodb::velocypack::Slice next() = 0;
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virtual size_t count() const = 0;
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virtual void dump(velocypack::Builder&) = 0;
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protected:
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CursorId const _id;
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size_t const _batchSize;
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size_t _position;
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std::shared_ptr<arangodb::velocypack::Builder> const _extra;
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double _ttl;
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double _expires;
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bool const _hasCount;
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bool _isDeleted;
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bool _isUsed;
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};
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class VelocyPackCursor final : public Cursor {
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public:
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VelocyPackCursor(TRI_vocbase_t*, CursorId, aql::QueryResult&&, size_t,
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std::shared_ptr<arangodb::velocypack::Builder>, double,
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bool);
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~VelocyPackCursor() = default;
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public:
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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() override final;
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arangodb::velocypack::Slice next() override final;
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size_t count() const override final;
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void dump(velocypack::Builder&) override final;
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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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}
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#endif
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