scope.h

/* Copyright (c) 2016 Baidu, Inc. All Rights Reserved.
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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
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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