Fabric: Introducing `ContextContainer`

Summary:
@public
`ContextContainer` is general purpose DI container for Fabric.
We need this to communicate some enviroment-specific and/or platform-specific modules down to cross-platform C++ code.
The first one will be ImageManager. Soon.

Reviewed By: fkgozali

Differential Revision: D8475636

fbshipit-source-id: 0afc65063f818d0bab736cd2c55c6fdd21b629ac

React/Fabric/RCTScheduler.mm

@@ -7,6 +7,7 @@
 
 #import "RCTScheduler.h"
 
+#import <fabric/uimanager/ContextContainer.h>
 #import <fabric/uimanager/Scheduler.h>
 #import <fabric/uimanager/SchedulerDelegate.h>
 
@@ -41,7 +42,9 @@ private:
 {
   if (self = [super init]) {
     _delegateProxy = std::make_shared<SchedulerDelegateProxy>((__bridge void *)self);
-    _scheduler = std::make_shared<Scheduler>();
+
+    SharedContextContainer contextContainer = std::make_shared<ContextContainer>();
+    _scheduler = std::make_shared<Scheduler>(contextContainer);
     _scheduler->setDelegate(_delegateProxy.get());
   }
 

ReactCommon/fabric/sample/SampleComponentDescriptorFactor.cpp

@@ -7,6 +7,7 @@
 
 #include <fabric/uimanager/ComponentDescriptorFactory.h>
 #include <fabric/uimanager/ComponentDescriptorRegistry.h>
+#include <fabric/uimanager/ContextContainer.h>
 
 namespace facebook {
 namespace react {
@@ -14,7 +15,10 @@ namespace react {
 /**
  * This is a sample implementation. Each app should provide its own.
  */
-SharedComponentDescriptorRegistry ComponentDescriptorFactory::buildRegistry(const SharedEventDispatcher &eventDispatcher) {
+SharedComponentDescriptorRegistry ComponentDescriptorFactory::buildRegistry(
+  const SharedEventDispatcher &eventDispatcher,
+  const SharedContextContainer &contextContainer
+) {
   auto registry = std::make_shared<ComponentDescriptorRegistry>();
   return registry;
 }

ReactCommon/fabric/uimanager/ComponentDescriptorFactory.h

@@ -11,6 +11,7 @@
 
 #include <fabric/core/ComponentDescriptor.h>
 #include <fabric/core/EventDispatcher.h>
+#include <fabric/uimanager/ContextContainer.h>
 
 #include "ComponentDescriptorRegistry.h"
 
@@ -25,7 +26,7 @@ namespace react {
 class ComponentDescriptorFactory {
 
 public:
-  static SharedComponentDescriptorRegistry buildRegistry(const SharedEventDispatcher &eventDispatcher);
+  static SharedComponentDescriptorRegistry buildRegistry(const SharedEventDispatcher &eventDispatcher, const SharedContextContainer &contextContainer);
 };
 
 } // namespace react

ReactCommon/fabric/uimanager/ContextContainer.cpp

@@ -0,0 +1,22 @@
+// 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.
+
+#include "ContextContainer.h"
+
+namespace facebook {
+namespace react {
+
+void ContextContainer::registerInstance(const ClassHandle &handle, SharedInstance instance) {
+  std::lock_guard<std::mutex> lock(mutex_);
+  instances_.insert({handle, instance});
+}
+
+const ContextContainer::SharedInstance &ContextContainer::at(const ClassHandle &handle) const {
+  std::lock_guard<std::mutex> lock(mutex_);
+  return instances_.at(handle);
+}
+
+} // namespace react
+} // namespace facebook

ReactCommon/fabric/uimanager/ContextContainer.h

@@ -0,0 +1,40 @@
+// 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.
+ */
+class ContextContainer final {
+
+public:
+  using ClassHandle = std::type_index;
+  using SharedInstance = std::shared_ptr<void>;
+
+  void registerInstance(const ClassHandle &handle, SharedInstance instance);
+
+  const SharedInstance &at(const ClassHandle &handle) const;
+
+private:
+  std::unordered_map<ClassHandle, SharedInstance> instances_;
+  mutable std::mutex mutex_;
+};
+
+} // namespace react
+} // namespace facebook

ReactCommon/fabric/uimanager/Scheduler.cpp

@@ -22,9 +22,10 @@
 namespace facebook {
 namespace react {
 
-Scheduler::Scheduler() {
+Scheduler::Scheduler(const SharedContextContainer &contextContainer):
+  contextContainer_(contextContainer) {
   auto &&eventDispatcher = std::make_shared<SchedulerEventDispatcher>();
-  auto &&componentDescriptorRegistry = ComponentDescriptorFactory::buildRegistry(eventDispatcher);
+  auto &&componentDescriptorRegistry = ComponentDescriptorFactory::buildRegistry(eventDispatcher, contextContainer);
 
   uiManager_ = std::make_shared<FabricUIManager>(componentDescriptorRegistry);
   uiManager_->setDelegate(this);

ReactCommon/fabric/uimanager/Scheduler.h

@@ -9,6 +9,7 @@
 
 #include <fabric/core/ComponentDescriptor.h>
 #include <fabric/core/LayoutConstraints.h>
+#include <fabric/uimanager/ContextContainer.h>
 #include <fabric/uimanager/SchedulerDelegate.h>
 #include <fabric/uimanager/SchedulerEventDispatcher.h>
 #include <fabric/uimanager/UIManagerDelegate.h>
@@ -31,7 +32,7 @@ class Scheduler final:
 
 public:
 
-  Scheduler();
+  Scheduler(const SharedContextContainer &contextContainer);
   ~Scheduler();
 
 #pragma mark - Shadow Tree Management
@@ -74,6 +75,7 @@ private:
   std::shared_ptr<FabricUIManager> uiManager_;
   std::unordered_map<Tag, SharedShadowTree> shadowTreeRegistry_;
   SharedSchedulerEventDispatcher eventDispatcher_;
+  SharedContextContainer contextContainer_;
 };
 
 } // namespace react