Valentin Shergin 9395485822 Fabric: ContextContainer is now able to store any copyable values
Summary:
@public
Previously, ContextContainer could store only `shared_ptr`s, but now it wraps all values in own `shared_ptr` container.
I wish we can use `unique_ptr` here, but apparently we cannot because `unique_ptr` does not support type-erasure (`std::unique_ptr<void>` is illigal).
Becasue ContextContainer is not supposed to be used in hot paths, the performance aspect of that does not actually matter.

Reviewed By: mdvacca

Differential Revision: D8853446

fbshipit-source-id: e5d0a5595fe44c59f1395d6ffccf9d3fed923c83
2018-07-17 22:53:57 -07:00

66 lines
1.5 KiB
C++

// Copyright (c) 2004-present, Facebook, Inc.
// This source code is licensed under the MIT license found in the
// LICENSE file in the root directory of this source tree.
#pragma once
#include <memory>
#include <mutex>
#include <typeindex>
#include <typeinfo>
#include <unordered_map>
namespace facebook {
namespace react {
class ContextContainer;
using SharedContextContainer = std::shared_ptr<ContextContainer>;
/*
* General purpose dependecy injection container.
* Instance types must be copyable.
*/
class ContextContainer final {
public:
/*
* Registers an instance of the particular type `T` in the container.
* If `key` parameter is specified, the instance is registered
* by `{type, key}` pair.
*/
template<typename T>
void registerInstance(const T &instance, const std::string &key = "") {
std::lock_guard<std::mutex> lock(mutex_);
instances_.insert({
{std::type_index(typeid(T)), key},
std::make_shared<T>(instance)
});
}
/*
* Returns a previously registered instance of the particular type `T`.
* If `key` parameter is specified, the lookup will be performed
* by {type, key} pair.
*/
template<typename T>
T getInstance(const std::string &key = "") const {
std::lock_guard<std::mutex> lock(mutex_);
return *std::static_pointer_cast<T>(instances_.at({std::type_index(typeid(T)), key}));
}
private:
std::unordered_map<
std::pair<std::type_index, std::string>,
std::shared_ptr<void>
> instances_;
mutable std::mutex mutex_;
};
} // namespace react
} // namespace facebook