mirror of https://gitee.com/bigwinds/arangodb
96 lines
3.1 KiB
C++
96 lines
3.1 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2018 ArangoDB 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 Christoph Uhde
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////////////////////////////////////////////////////////////////////////////////
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#include "Aql/ConstFetcher.h"
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#include "Aql/AqlItemBlock.h"
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#include "Aql/DependencyProxy.h"
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#include "Aql/FilterExecutor.h"
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#include "ConstFetcher.h"
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using namespace arangodb;
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using namespace arangodb::aql;
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ConstFetcher::ConstFetcher() : _currentBlock{nullptr}, _rowIndex(0) {}
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ConstFetcher::ConstFetcher(DependencyProxy& executionBlock)
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: _currentBlock{nullptr}, _rowIndex(0) {}
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void ConstFetcher::injectBlock(SharedAqlItemBlockPtr block) {
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_currentBlock = block;
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_blockForPassThrough = std::move(block);
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_rowIndex = 0;
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}
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std::pair<ExecutionState, InputAqlItemRow> ConstFetcher::fetchRow() {
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// This fetcher never waits because it can return only its
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// injected block and does not have the ability to pull.
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if (!indexIsValid()) {
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return {ExecutionState::DONE, InputAqlItemRow{CreateInvalidInputRowHint{}}};
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}
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TRI_ASSERT(_currentBlock != nullptr);
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//set state
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ExecutionState rowState = ExecutionState::HASMORE;
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if (isLastRowInBlock()) {
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rowState = ExecutionState::DONE;
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}
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return {rowState, InputAqlItemRow{_currentBlock, _rowIndex++}};
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}
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std::pair<ExecutionState, size_t> ConstFetcher::skipRows(size_t) {
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// This fetcher never waits because it can return only its
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// injected block and does not have the ability to pull.
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if (!indexIsValid()) {
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return {ExecutionState::DONE, 0};
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}
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TRI_ASSERT(_currentBlock != nullptr);
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//set state
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ExecutionState rowState = ExecutionState::HASMORE;
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if (isLastRowInBlock()) {
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rowState = ExecutionState::DONE;
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}
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_rowIndex++;
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return {rowState, 1};
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}
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bool ConstFetcher::indexIsValid() {
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return _currentBlock != nullptr && _rowIndex + 1 <= _currentBlock->size();
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}
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bool ConstFetcher::isLastRowInBlock() {
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TRI_ASSERT(indexIsValid());
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return _rowIndex + 1 == _currentBlock->size();
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}
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std::pair<ExecutionState, SharedAqlItemBlockPtr> ConstFetcher::fetchBlockForPassthrough(size_t) {
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// Should only be called once, and then _blockForPassThrough should be
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// initialized. However, there are still some blocks left that ask their
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// parent even after they got DONE the last time, and I don't currently have
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// time to track them down. Thus the following assert is commented out.
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// TRI_ASSERT(_blockForPassThrough != nullptr);
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return {ExecutionState::DONE, std::move(_blockForPassThrough)};
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}
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