mirror of https://gitee.com/bigwinds/arangodb
158 lines
4.4 KiB
C++
158 lines
4.4 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_SCOPES_H
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#define ARANGOD_AQL_SCOPES_H 1
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#include "Aql/Variable.h"
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#include "Basics/Common.h"
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namespace arangodb {
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namespace aql {
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enum ScopeType {
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AQL_SCOPE_MAIN,
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AQL_SCOPE_SUBQUERY,
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AQL_SCOPE_FOR,
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AQL_SCOPE_COLLECT
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};
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class Scope {
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public:
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/// @brief create a scope
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Scope(ScopeType);
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/// @brief destroy the scope
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~Scope();
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public:
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/// @brief return the name of a scope type
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std::string typeName() const;
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/// @brief return the name of a scope type
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static std::string typeName(ScopeType);
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/// @brief return the scope type
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inline ScopeType type() const { return _type; }
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/// @brief adds a variable to the scope
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void addVariable(Variable*);
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/// @brief checks if a variable exists in the scope
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bool existsVariable(char const*, size_t) const;
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/// @brief checks if a variable exists in the scope
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bool existsVariable(std::string const&) const;
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/// @brief return a variable
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Variable const* getVariable(char const*, size_t) const;
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/// @brief return a variable
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Variable const* getVariable(std::string const&) const;
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/// @brief return a variable, allowing usage of special pseudo vars such
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/// as OLD and NEW
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Variable const* getVariable(char const*, size_t, bool) const;
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private:
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/// @brief scope type
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ScopeType const _type;
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/// @brief variables introduced by the scope
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std::unordered_map<std::string, Variable*> _variables;
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};
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/// @brief scope management
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class Scopes {
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public:
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/// @brief create the scopes
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Scopes();
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/// @brief destroy the scopes
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~Scopes();
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public:
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/// @brief number of currently active scopes
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inline size_t numActive() const { return _activeScopes.size(); }
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/// @brief return the type of the currently active scope
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ScopeType type() const {
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TRI_ASSERT(numActive() > 0);
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return _activeScopes.back()->type();
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}
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/// @brief whether or not the $CURRENT variable can be used at the caller's
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/// current position
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inline bool canUseCurrentVariable() const {
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return (!_currentVariables.empty());
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}
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/// @brief start a new scope
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void start(ScopeType);
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/// @brief end the current scope
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void endCurrent();
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/// @brief end the current scope plus any FOR scopes it is nested in
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void endNested();
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/// @brief adds a variable to the current scope
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void addVariable(Variable*);
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/// @brief replaces an existing variable in the current scope
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void replaceVariable(Variable*);
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/// @brief checks whether a variable exists in any scope
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bool existsVariable(char const*, size_t) const;
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/// @brief return a variable by name - this respects the current scopes
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Variable const* getVariable(char const*, size_t) const;
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/// @brief return a variable by name - this respects the current scopes
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Variable const* getVariable(std::string const&) const;
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/// @brief return a variable by name - this respects the current scopes
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/// this also allows using special pseudo vars such as OLD and NEW
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Variable const* getVariable(char const*, size_t, bool) const;
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/// @brief get the $CURRENT variable
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Variable const* getCurrentVariable() const;
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/// @brief stack a $CURRENT variable from the stack
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void stackCurrentVariable(Variable const*);
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/// @brief unregister the $CURRENT variable from the stack
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void unstackCurrentVariable();
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private:
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/// @brief currently active scopes
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std::vector<std::unique_ptr<Scope>> _activeScopes;
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/// @brief a stack with aliases for the $CURRENT variable
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std::vector<Variable const*> _currentVariables;
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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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