mirror of https://gitee.com/bigwinds/arangodb
138 lines
4.0 KiB
C++
138 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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#include "IndexIterator.h"
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#include "Basics/StringUtils.h"
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#include "Cluster/ServerState.h"
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#include "Indexes/Index.h"
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#include "Utils/CollectionNameResolver.h"
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using namespace arangodb;
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IndexIterator::IndexIterator(LogicalCollection* collection,
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arangodb::Transaction* trx,
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ManagedDocumentResult* mmdr,
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arangodb::Index const* index)
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: _collection(collection),
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_trx(trx),
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_mmdr(mmdr ? mmdr : new ManagedDocumentResult(trx)),
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_context(trx, collection, _mmdr, index->fields().size()),
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_responsible(mmdr == nullptr) {
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TRI_ASSERT(_collection != nullptr);
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TRI_ASSERT(_trx != nullptr);
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TRI_ASSERT(_mmdr != nullptr);
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}
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/// @brief default destructor. Does not free anything
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IndexIterator::~IndexIterator() {
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if (_responsible) {
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delete _mmdr;
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}
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}
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/// @brief default implementation for next
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IndexLookupResult IndexIterator::next() { return IndexLookupResult(); }
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/// @brief default implementation for nextBabies
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void IndexIterator::nextBabies(std::vector<IndexLookupResult>& result, size_t batchSize) {
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result.clear();
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if (batchSize > 0) {
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while (true) {
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IndexLookupResult element = next();
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if (!element) {
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return;
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}
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result.emplace_back(element);
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batchSize--;
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if (batchSize == 0) {
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return;
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}
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}
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}
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}
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/// @brief default implementation for reset
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void IndexIterator::reset() {}
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/// @brief default implementation for skip
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void IndexIterator::skip(uint64_t count, uint64_t& skipped) {
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// Skip the first count-many entries
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// TODO: Can be improved
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while (count > 0 && next()) {
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--count;
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skipped++;
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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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IndexLookupResult MultiIndexIterator::next() {
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if (_current == nullptr) {
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return IndexLookupResult();
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}
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IndexLookupResult next = _current->next();
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while (!next) {
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_currentIdx++;
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if (_currentIdx >= _iterators.size()) {
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_current = nullptr;
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return IndexLookupResult();
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}
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_current = _iterators.at(_currentIdx);
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next = _current->next();
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}
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return next;
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}
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/// @brief Get the next limit many elements
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/// If one iterator is exhausted, the next one will be used.
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/// An empty result vector indicates that all iterators are exhausted
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void MultiIndexIterator::nextBabies(std::vector<IndexLookupResult>& result, size_t limit) {
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result.clear();
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if (_current == nullptr) {
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return;
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}
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_current->nextBabies(result, limit);
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while (result.empty()) {
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_currentIdx++;
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if (_currentIdx >= _iterators.size()) {
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_current = nullptr;
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return;
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}
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_current = _iterators.at(_currentIdx);
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_current->nextBabies(result, limit);
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}
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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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void MultiIndexIterator::reset() {
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_current = _iterators.at(0);
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_currentIdx = 0;
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for (auto& it : _iterators) {
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it->reset();
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}
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}
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