mirror of https://gitee.com/bigwinds/arangodb
103 lines
3.1 KiB
C++
103 lines
3.1 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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#ifndef ARANGOD_AQL_VARIABLE_H
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#define ARANGOD_AQL_VARIABLE_H 1
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#include "Aql/types.h"
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#include "Basics/Common.h"
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namespace arangodb {
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namespace velocypack {
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class Builder;
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class Slice;
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} // namespace velocypack
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namespace aql {
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class Ast;
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struct Variable {
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/// @brief create the variable
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Variable(std::string const&, VariableId);
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explicit Variable(arangodb::velocypack::Slice const&);
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Variable* clone() const { return new Variable(name, id); }
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/// @brief destroy the variable
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~Variable();
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/// @brief registers a constant value for the variable
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/// this constant value is used for constant propagation in optimizations
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void constValue(void* node) { value = node; }
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/// @brief returns a constant value registered for this variable
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inline void* constValue() const { return value; }
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/// @brief whether or not the variable is user-defined
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inline bool isUserDefined() const {
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char const c = name[0];
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// variables starting with a number are not user-defined
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return (c < '0' || c > '9');
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}
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/// @brief whether or not the variable needs a register assigned
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inline bool needsRegister() const {
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// variables starting with a number are not user-defined
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return isUserDefined() || name.back() != '_';
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}
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/// @brief return a VelocyPack representation of the variable
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void toVelocyPack(arangodb::velocypack::Builder&) const;
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/// @brief replace a variable by another
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static Variable const* replace(Variable const*,
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std::unordered_map<VariableId, Variable const*> const&);
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/// @brief factory for (optional) variables from VPack
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static Variable* varFromVPack(Ast* ast, arangodb::velocypack::Slice const& base,
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char const* variableName, bool optional = false);
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/// @brief variable name
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std::string name;
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/// @brief constant variable value (points to another AstNode)
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void* value;
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/// @brief variable id
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VariableId const id;
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/// @brief name of $OLD variable
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static char const* const NAME_OLD;
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/// @brief name of $NEW variable
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static char const* const NAME_NEW;
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/// @brief name of $CURRENT variable
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static char const* const NAME_CURRENT;
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};
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} // namespace aql
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} // namespace arangodb
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#endif
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