mirror of https://gitee.com/bigwinds/arangodb
144 lines
3.8 KiB
C++
144 lines
3.8 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/ExecutionState.h"
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#include "Basics/Common.h"
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#include "Basics/system-functions.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 transaction {
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class Context;
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}
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namespace velocypack {
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class Builder;
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class Slice;
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} // namespace velocypack
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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 { CURSOR_VPACK, CURSOR_EXPORT };
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Cursor(Cursor const&) = delete;
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Cursor& operator=(Cursor const&) = delete;
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Cursor(CursorId id, size_t batchSize, double ttl, bool hasCount)
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: _id(id),
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_batchSize(batchSize),
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_ttl(ttl),
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_expires(TRI_microtime() + _ttl),
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_hasCount(hasCount),
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_isDeleted(false),
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_isUsed(false) {}
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virtual ~Cursor() = default;
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public:
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CursorId id() const { return _id; }
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inline size_t batchSize() const { return _batchSize; }
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inline bool hasCount() const { return _hasCount; }
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inline double ttl() const { return _ttl; }
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inline double expires() const { return _expires; }
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inline bool isUsed() const { return _isUsed; }
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inline bool isDeleted() const { return _isDeleted; }
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void setDeleted() { _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 void kill() {}
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virtual size_t count() const = 0;
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virtual std::shared_ptr<transaction::Context> context() const = 0;
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/**
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* @brief Dump the cursor result, async version. The caller needs to be
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* contiueable
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*
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* @param result The Builder to write the result to
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* @param continueHandler The function that is posted on scheduler to contiue
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* this execution.
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*
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* @return First: ExecutionState either DONE or WAITING. On Waiting we need to
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* free this thread on DONE we have a result. Second: Result If State==DONE
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* this contains Error information or NO_ERROR. On NO_ERROR result is filled.
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*/
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virtual std::pair<aql::ExecutionState, Result> dump(velocypack::Builder& result) = 0;
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/**
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* @brief Dump the cursor result. This is guaranteed to return the result in
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* this thread.
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*
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* @param result the Builder to write the result to
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*
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* @return ErrorResult, if something goes wrong
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*/
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virtual Result dumpSync(velocypack::Builder& result) = 0;
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/// Set wakeup handler on streaming cursor
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virtual void setWakeupHandler(std::function<bool()> const& cb) {}
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virtual void resetWakeupHandler() {}
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protected:
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CursorId const _id;
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size_t const _batchSize;
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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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} // namespace arangodb
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#endif
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