mirror of https://gitee.com/bigwinds/arangodb
124 lines
4.0 KiB
C++
124 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 "OperationCursor.h"
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#include "OperationResult.h"
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#include "Basics/Exceptions.h"
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#include "Logger/Logger.h"
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#include "VocBase/MasterPointer.h"
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using namespace arangodb;
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void OperationCursor::reset() {
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if (_indexIterator != nullptr) {
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_indexIterator->reset();
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_hasMore = true;
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_limit = _originalLimit;
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}
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}
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//////////////////////////////////////////////////////////////////////////////
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/// @brief Get next batchSize many elements.
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/// Defaults to _batchSize
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/// Check hasMore()==true before using this
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/// NOTE: This will throw on OUT_OF_MEMORY
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//////////////////////////////////////////////////////////////////////////////
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std::shared_ptr<OperationResult> OperationCursor::getMore(uint64_t batchSize,
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bool useExternals) {
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auto res = std::make_shared<OperationResult>(TRI_ERROR_NO_ERROR);
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getMore(res, batchSize, useExternals);
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return res;
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}
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void OperationCursor::getMore(std::shared_ptr<OperationResult>& opRes,
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uint64_t batchSize, bool useExternals) {
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if (opRes == nullptr) {
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// Create a valid pointer if none is given
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auto tmp = std::make_shared<OperationResult>(TRI_ERROR_NO_ERROR);
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opRes.swap(tmp);
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}
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// This may throw out of memory
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if (!hasMore()) {
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TRI_ASSERT(false);
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// You requested more even if you should have checked it before.
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opRes->code = TRI_ERROR_FORBIDDEN;
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}
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if (batchSize == UINT64_MAX) {
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batchSize = _batchSize;
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}
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VPackBuilder builder(opRes->buffer);
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builder.clear();
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try {
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VPackArrayBuilder guard(&builder);
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TRI_doc_mptr_t* mptr = nullptr;
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// TODO: Improve this for baby awareness
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while (batchSize > 0 && _limit > 0 && (mptr = _indexIterator->next()) != nullptr) {
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--batchSize;
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--_limit;
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if (useExternals) {
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builder.add(VPackValue(mptr->vpack(), VPackValueType::External));
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} else {
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builder.add(VPackSlice(mptr->vpack()));
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}
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}
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if (batchSize > 0 || _limit == 0) {
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// Iterator empty, there is no more
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_hasMore = false;
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}
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opRes->code = TRI_ERROR_NO_ERROR;
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} catch (arangodb::basics::Exception const& e) {
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opRes->code = e.code();
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}
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}
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//////////////////////////////////////////////////////////////////////////////
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/// @brief Skip the next toSkip many elements.
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/// skipped will be increased by the amount of skipped elements afterwards
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/// Check hasMore()==true before using this
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/// NOTE: This will throw on OUT_OF_MEMORY
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//////////////////////////////////////////////////////////////////////////////
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int OperationCursor::skip(uint64_t toSkip, uint64_t& skipped) {
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if (!hasMore()) {
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TRI_ASSERT(false);
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// You requested more even if you should have checked it before.
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return TRI_ERROR_FORBIDDEN;
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}
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if (toSkip > _limit) {
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// Short-cut, we jump to the end
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_limit = 0;
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_hasMore = false;
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return TRI_ERROR_NO_ERROR;
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}
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_indexIterator->skip(toSkip, skipped);
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_limit -= skipped;
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if (skipped != toSkip || _limit == 0) {
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_hasMore = false;
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}
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return TRI_ERROR_NO_ERROR;
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}
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