mirror of https://gitee.com/bigwinds/arangodb
123 lines
4.0 KiB
C++
123 lines
4.0 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 Michael Hackstein
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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGOD_INDEXES_INDEX_ITERATOR_H
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#define ARANGOD_INDEXES_INDEX_ITERATOR_H 1
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#include "Basics/Common.h"
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#include "VocBase/vocbase.h"
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namespace arangodb {
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class CollectionNameResolver;
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////////////////////////////////////////////////////////////////////////////////
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/// @brief context for an index iterator
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////////////////////////////////////////////////////////////////////////////////
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struct IndexIteratorContext {
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IndexIteratorContext(TRI_vocbase_t*, CollectionNameResolver const*);
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explicit IndexIteratorContext(TRI_vocbase_t*);
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~IndexIteratorContext();
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CollectionNameResolver const* getResolver() const;
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bool isCluster() const;
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int resolveId(char const*, TRI_voc_cid_t&, char const*&) const;
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TRI_vocbase_t* vocbase;
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mutable CollectionNameResolver const* resolver;
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bool ownsResolver;
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};
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////////////////////////////////////////////////////////////////////////////////
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/// @brief a base class to iterate over the index. An iterator is requested
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/// at the index itself
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////////////////////////////////////////////////////////////////////////////////
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class IndexIterator {
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public:
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IndexIterator(IndexIterator const&) = delete;
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IndexIterator& operator=(IndexIterator const&) = delete;
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IndexIterator() {}
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virtual ~IndexIterator();
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virtual TRI_doc_mptr_t* next();
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virtual void reset();
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virtual void skip(uint64_t count, uint64_t& skipped);
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};
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////////////////////////////////////////////////////////////////////////////////
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/// @brief a wrapper class to iterate over several IndexIterators.
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/// Each iterator is requested at the index itself.
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/// This iterator does NOT check for uniqueness.
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/// Will always start with the first iterator in the vector. Reverse them
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/// Outside if necessary.
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////////////////////////////////////////////////////////////////////////////////
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class MultiIndexIterator : public IndexIterator {
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public:
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explicit MultiIndexIterator(std::vector<IndexIterator*> const& iterators)
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: _iterators(iterators), _currentIdx(0), _current(nullptr) {
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if (!_iterators.empty()) {
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_current = _iterators.at(0);
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}
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};
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~MultiIndexIterator () {
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// Free all iterators
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for (auto& it : _iterators) {
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delete it;
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}
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};
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////////////////////////////////////////////////////////////////////////////////
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/// @brief Get the next element
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/// If one iterator is exhausted, the next one is used.
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/// A nullptr indicates that all iterators are exhausted
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////////////////////////////////////////////////////////////////////////////////
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TRI_doc_mptr_t* next() override;
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////////////////////////////////////////////////////////////////////////////////
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/// @brief Reset the cursor
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/// This will reset ALL internal iterators and start all over again
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////////////////////////////////////////////////////////////////////////////////
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void reset() override;
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private:
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std::vector<IndexIterator*> _iterators;
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size_t _currentIdx;
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IndexIterator* _current;
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};
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}
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#endif
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