Files
react-native/ReactCommon/utils/ContextContainer.h
T
Valentin Shergin 2688780394 Fabric: DEBUG-only check for type match in ContextContainer
Summary: Additional check verifies that requested type matches the type of a stored value.

Reviewed By: mdvacca

Differential Revision: D14944336

fbshipit-source-id: 6d3a1654d9b9a64ced83f553236093f02f2c97c7
2019-04-22 08:36:08 -07:00

79 lines
2.3 KiB
C++

// Copyright (c) Facebook, Inc. and its affiliates.
// 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 <string>
#include <better/map.h>
#include <better/mutex.h>
#include <better/optional.h>
namespace facebook {
namespace react {
/*
* General purpose dependecy injection container.
* Instance types must be copyable.
*/
class ContextContainer final {
public:
using Shared = std::shared_ptr<ContextContainer const>;
/*
* Registers an instance of the particular type `T` in the container
* using the provided `key`. Only one instance can be registered per key.
*
* Convention is to use the plain base class name for the key, so for
* example if the type `T` is `std::shared_ptr<const ReactNativeConfig>`,
* then one would use `"ReactNativeConfig"` for the `key`, even if the
* instance is actually a `shared_ptr` of derived class
*`EmptyReactNativeConfig`.
*/
template <typename T>
void registerInstance(T const &instance, std::string const &key) const {
std::unique_lock<better::shared_mutex> lock(mutex_);
assert(
instances_.find(key) == instances_.end() &&
"ContextContainer already had instance for given key.");
instances_.insert({key, std::make_shared<T>(instance)});
#ifndef NDEBUG
typeHashes_.insert({key, typeid(T).hash_code()});
#endif
}
/*
* Returns a previously registered instance of the particular type `T`
* for `key`.
*/
template <typename T>
T getInstance(std::string const &key) const {
std::shared_lock<better::shared_mutex> lock(mutex_);
assert(
instances_.find(key) != instances_.end() &&
"ContextContainer doesn't have an instance for given key.");
assert(
typeHashes_.at(key) == typeid(T).hash_code() &&
"ContextContainer stores an instance of different type for given key.");
return *std::static_pointer_cast<T>(instances_.at(key));
}
private:
mutable better::shared_mutex mutex_;
// Protected by mutex_`.
mutable better::map<std::string, std::shared_ptr<void>> instances_;
#ifndef NDEBUG
mutable better::map<std::string, size_t> typeHashes_;
#endif
};
} // namespace react
} // namespace facebook