mirror of
https://github.com/zhigang1992/react-native.git
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184cfd5594
Summary: So, changes: * Correctness checks only in debug mode (codesize win?); * `registerInstance` marked as const (because it's thread safe); * ContextContainer::Shared also enforces constness; * Using faster better::map; * Using shared/RW mutex instead of regular one; * SharedContextContainer got removed. Reviewed By: sahrens Differential Revision: D14920284 fbshipit-source-id: f0f8d970e7fae79a1abe3bc32827db9fd2d17e13
69 lines
2.0 KiB
C++
69 lines
2.0 KiB
C++
// Copyright (c) Facebook, Inc. and its affiliates.
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// This source code is licensed under the MIT license found in the
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// LICENSE file in the root directory of this source tree.
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#pragma once
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#include <memory>
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#include <mutex>
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#include <string>
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#include <better/map.h>
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#include <better/mutex.h>
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#include <better/optional.h>
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namespace facebook {
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namespace react {
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/*
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* General purpose dependecy injection container.
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* Instance types must be copyable.
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*/
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class ContextContainer final {
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public:
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using Shared = std::shared_ptr<const ContextContainer>;
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/*
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* Registers an instance of the particular type `T` in the container
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* using the provided `key`. Only one instance can be registered per key.
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*
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* Convention is to use the plain base class name for the key, so for
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* example if the type `T` is `std::shared_ptr<const ReactNativeConfig>`,
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* then one would use `"ReactNativeConfig"` for the `key`, even if the
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* instance is actually a `shared_ptr` of derived class
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*`EmptyReactNativeConfig`.
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*/
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template <typename T>
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void registerInstance(T const &instance, std::string const &key) const {
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std::unique_lock<better::shared_mutex> lock(mutex_);
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assert(
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instances_.find(key) == instances_.end() &&
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"ContextContainer already had instance for given key.");
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instances_.insert({key, std::make_shared<T>(instance)});
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}
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/*
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* Returns a previously registered instance of the particular type `T`
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* for `key`.
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*/
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template <typename T>
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T getInstance(std::string const &key) const {
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std::shared_lock<better::shared_mutex> lock(mutex_);
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assert(
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instances_.find(key) != instances_.end() &&
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"ContextContainer doesn't have an instance for given key.");
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return *std::static_pointer_cast<T>(instances_.at(key));
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}
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private:
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mutable better::shared_mutex mutex_;
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// Protected by mutex_`.
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mutable better::map<std::string, std::shared_ptr<void>> instances_;
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};
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} // namespace react
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} // namespace facebook
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