/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. */

#include "paddle/framework/scope.h"

#include <memory>  // for unique_ptr
#include <mutex>   // for call_once
#include "paddle/string/printf.h"

namespace paddle {
namespace framework {

Scope::~Scope() {
  DropKids();
  for (auto& kv : vars_) delete kv.second;
}

Scope& Scope::NewScope() const {
  kids_.push_back(new Scope(this));
  return *kids_.back();
}

Variable* Scope::GetOrCreateVar(const std::string& name) {
  auto iter = vars_.find(name);
  if (iter != vars_.end()) {
    return iter->second;
  }
  Variable* v = new Variable();
  vars_[name] = v;
  v->name_ = &(vars_.find(name)->first);
  return v;
}

Variable* Scope::GetOrCreateVar() {
  return GetOrCreateVar(string::Sprintf("%p.%d", this, vars_.size()));
}

Variable* Scope::FindVar(const std::string& name) const {
  auto it = vars_.find(name);
  if (it != vars_.end()) return it->second;
  return (parent_ == nullptr) ? nullptr : parent_->FindVar(name);
}

const Scope* Scope::FindScope(const Variable* var) const {
  for (auto& kv : vars_) {
    if (kv.second == var) {
      return this;
    }
  }
  return (parent_ == nullptr) ? nullptr : parent_->FindScope(var);
}
void Scope::DropKids() {
  for (Scope* s : kids_) delete s;
  kids_.clear();
}

std::once_flag feed_variable_flag;

framework::Scope& GetGlobalScope() {
  static std::unique_ptr<framework::Scope> g_scope{nullptr};
  std::call_once(feed_variable_flag, [&]() {
    g_scope.reset(new framework::Scope());
    g_scope->GetOrCreateVar("feed_value");
    g_scope->GetOrCreateVar("fetch_value");
  });
  return *(g_scope.get());
}

}  // namespace framework
}  // namespace paddle