scope.h

/* Copyright (c) 2016 Baidu, Inc. All Rights Reserved.
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
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The above copyright notice and this permission notice shall be included in all
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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SOFTWARE.
==============================================================================*/
#pragma once

#include "variable.h"
#include <list>          //std::list
#include <mutex>         //std::mutex
#include <unordered_map> //std::unordered_map

namespace paddle_mobile {
namespace framework {
class Scope {
  public:
    Scope() {}
    ~Scope() {}

    Scope &NewScope() const;

    /// Create a variable with given name if it doesn't exist.
    Variable *Var(const std::string &name);

    /// Create a variable with a scope-unique name.
    Variable *Var(std::string *name = nullptr);

    void EraseVars(const std::vector<std::string> &var_names);

    /// Find a variable in the scope or any of its ancestors.  Returns
    /// nullptr if cannot find.
    Variable *FindVar(const std::string &name) const;

    const Scope *parent() const { return parent_; }

    /// Find the scope or an ancestor scope that contains the given
    /// variable.
    const Scope *FindScope(const Variable *var) const;

    void DeleteScope(Scope *scope) const;

    /// Drop all kids scopes belonged to this scope.
    void DropKids();

    // enumerate all the variables current contains.
    std::vector<std::string> LocalVarNames() const;

    // Rename variable to a new name
    void Rename(const std::string &origin_name,
                const std::string &new_name) const;

    // Rename variable to a new name and return the new name
    std::string Rename(const std::string &origin_name) const;

    Variable *FindVarLocally(const std::string &name) const;

  private:
    // Call Scope::NewScope for a sub-scope.
    explicit Scope(Scope const *parent) : parent_(parent) {}

    mutable std::unordered_map<std::string, Variable *> vars_;
    mutable std::list<Scope *> kids_;
    Scope const *parent_{nullptr};

    mutable std::mutex mutex_;
};
} // namespace framework
} // namespace paddle_mobile