mirror of https://gitee.com/bigwinds/arangodb
116 lines
4.1 KiB
C++
116 lines
4.1 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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#include "AttributeAccessor.h"
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#include "Aql/AqlItemBlock.h"
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#include "Aql/ExpressionContext.h"
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#include "Aql/Variable.h"
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#include "Basics/StaticStrings.h"
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#include "Basics/VelocyPackHelper.h"
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#include "Transaction/Methods.h"
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using namespace arangodb;
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using namespace arangodb::aql;
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/// @brief create the accessor
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AttributeAccessor::AttributeAccessor(
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std::vector<std::string>&& attributeParts, Variable const* variable,
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bool dataIsFromCollection)
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: _attributeParts(attributeParts),
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_variable(variable),
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_type(EXTRACT_MULTI) {
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TRI_ASSERT(_variable != nullptr);
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TRI_ASSERT(!_attributeParts.empty());
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// determine accessor type
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// it is only safe to use the optimized accessor functions for system attributes
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// when the input data are collection documents. it is not safe to use them for
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// non-collection data, as the optimized functions may easily create out-of-bounds
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// accesses in that case
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if (_attributeParts.size() == 1) {
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if (dataIsFromCollection && attributeParts[0] == StaticStrings::KeyString) {
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_type = EXTRACT_KEY;
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} else if (dataIsFromCollection && attributeParts[0] == StaticStrings::IdString) {
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_type = EXTRACT_ID;
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} else if (dataIsFromCollection && attributeParts[0] == StaticStrings::FromString) {
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_type = EXTRACT_FROM;
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} else if (dataIsFromCollection && attributeParts[0] == StaticStrings::ToString) {
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_type = EXTRACT_TO;
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} else {
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_type = EXTRACT_SINGLE;
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}
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}
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}
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/// @brief replace the variable in the accessor
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void AttributeAccessor::replaceVariable(std::unordered_map<VariableId, Variable const*> const& replacements) {
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for (auto const& it : replacements) {
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if (it.first == _variable->id) {
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_variable = it.second;
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return;
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}
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}
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}
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/// @brief execute the accessor
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AqlValue AttributeAccessor::getSystem(transaction::Methods* trx,
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ExpressionContext* context, bool& mustDestroy) {
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AqlValue const& value = context->getVariableValue(_variable, false, mustDestroy);
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// get the AQL value
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switch (_type) {
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case EXTRACT_KEY:
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return value.getKeyAttribute(trx, mustDestroy, true);
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case EXTRACT_ID:
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return value.getIdAttribute(trx, mustDestroy, true);
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case EXTRACT_FROM:
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return value.getFromAttribute(trx, mustDestroy, true);
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case EXTRACT_TO:
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return value.getToAttribute(trx, mustDestroy, true);
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default: {
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mustDestroy = false;
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return AqlValue(AqlValueHintNull());
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}
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}
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}
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/// @brief execute the accessor
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AqlValue AttributeAccessor::getDynamic(transaction::Methods* trx,
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ExpressionContext* context, bool& mustDestroy) {
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AqlValue const& value = context->getVariableValue(_variable, false, mustDestroy);
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// get the AQL value
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switch (_type) {
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case EXTRACT_SINGLE:
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// use optimized version for single attribute (e.g. variable.attr)
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return value.get(trx, _attributeParts[0], mustDestroy, true);
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case EXTRACT_MULTI:
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// use general version for multiple attributes (e.g. variable.attr.subattr)
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return value.get(trx, _attributeParts, mustDestroy, true);
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default: {
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mustDestroy = false;
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return AqlValue(AqlValueHintNull());
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}
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}
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}
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