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Paddle/paddle/fluid/framework/variable.h

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2.9 KiB

// Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
//
// 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.
#pragma once
#include <memory>
#include <typeindex>
#include <typeinfo>
#include "paddle/fluid/platform/enforce.h"
namespace paddle {
namespace framework {
class Variable {
public:
template <typename T>
const T& Get() const {
PADDLE_ENFORCE(holder_ != nullptr, "Variable must hold some thing");
PADDLE_ENFORCE(IsType<T>(),
"Variable must be type %s, the holding type is %s",
typeid(T).name(), holder_->Type().name());
return *static_cast<const T*>(holder_->Ptr());
}
bool IsInitialized() const { return holder_ != nullptr; }
template <typename T>
T* GetMutable() {
if (!IsType<T>()) {
holder_.reset(new PlaceholderImpl<T>(new T()));
}
return static_cast<T*>(holder_->Ptr());
}
template <typename T>
bool IsType() const {
return holder_ != nullptr &&
std::type_index(typeid(T)) == std::type_index(holder_->Type());
}
void Clear() { holder_.reset(); }
std::type_index Type() const {
PADDLE_ENFORCE(holder_ != nullptr, "Must hold memory");
return holder_->Type();
}
private:
struct Placeholder {
virtual ~Placeholder() {}
virtual const std::type_info& Type() const = 0;
virtual void* Ptr() const = 0;
};
// Placeholder hides type T, so it doesn't appear as a template
// parameter of Variable.
template <typename T>
struct PlaceholderImpl : public Placeholder {
PlaceholderImpl(T* ptr) : ptr_(ptr), type_(typeid(T)) {}
virtual const std::type_info& Type() const { return type_; }
virtual void* Ptr() const { return static_cast<void*>(ptr_.get()); }
std::unique_ptr<T> ptr_;
const std::type_info& type_;
};
std::unique_ptr<Placeholder>
holder_; // pointers to a PlaceholderImpl object indeed.
// name_ is only meaningful with a Scope and accessible by it.
//
// NOTE: Please don't expose name_ by adding methods like
// Variable::Name or Scope::VarName! A variable could have a human
// readable name or an auto-generated scope-unique name. In the
// former case, the caller knows the name and doesn't need to access
// the name; in the latter case, the variable should be identified
// by its address but not the unreadable name.
friend class Scope;
const std::string* name_;
};
} // namespace framework
} // namespace paddle