9 files changed, 354 insertions, 0 deletions
diff --git a/Firebase/Core/Private/FIRAppAssociationRegistration.h b/Firebase/Core/Private/FIRAppAssociationRegistration.h
index a1f8c41..007e2bf 100644
--- a/Firebase/Core/Private/FIRAppAssociationRegistration.h
+++ b/Firebase/Core/Private/FIRAppAssociationRegistration.h
@@ -18,6 +18,7 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+//  TODO: Remove this once Auth moves over to Core's instance registration system.
 /** @class FIRAppAssociationRegistration
     @brief Manages object associations as a singleton-dependent: At most one object is
         registered for any given host/key pair, and the object shall be created on-the-fly when
diff --git a/Firebase/Core/Private/FIRAppInternal.h b/Firebase/Core/Private/FIRAppInternal.h
index 66979eb..45de2ba 100644
--- a/Firebase/Core/Private/FIRAppInternal.h
+++ b/Firebase/Core/Private/FIRAppInternal.h
@@ -17,6 +17,9 @@
 #import "FIRApp.h"
 #import "FIRErrors.h"
 
+@class FIRComponentContainer;
+@protocol FIRCoreConfigurable;
+
 /**
  * The internal interface to FIRApp. This is meant for first-party integrators, who need to receive
  * FIRApp notifications, log info about the success or failure of their configuration, and access
@@ -126,6 +129,11 @@ typedef NSString *_Nullable (^FIRAppGetUIDImplementation)(void);
 
 @interface FIRApp ()
 
+/**
+ * A flag indicating if this is the default app.
+ */
+@property(nonatomic, readonly) BOOL isDefaultApp;
+
 /** @property getTokenImplementation
     @brief Gets or sets the block to use for the implementation of
         @c getTokenForcingRefresh:withCallback:
@@ -137,6 +145,11 @@ typedef NSString *_Nullable (^FIRAppGetUIDImplementation)(void);
  */
 @property(nonatomic, copy) FIRAppGetUIDImplementation getUIDImplementation;
 
+/*
+ * The container of interop SDKs for this app.
+ */
+@property(nonatomic) FIRComponentContainer *container;
+
 /**
  * Creates an error for failing to configure a subspec service. This method is called by each
  * FIRApp notification listener.
@@ -151,6 +164,13 @@ typedef NSString *_Nullable (^FIRAppGetUIDImplementation)(void);
 + (BOOL)isDefaultAppConfigured;
 
 /**
+ * Register a class that conforms to `FIRCoreConfigurable`. Each SDK should have one class that
+ * registers in order to provide critical information for interoperability and lifecycle events.
+ * TODO(wilsonryan): Write more documentation.
+ */
++ (void)registerAsConfigurable:(Class<FIRCoreConfigurable>)klass;
+
+/**
  * Registers a given third-party library with the given version number to be reported for
  * analyitcs.
  *
diff --git a/Firebase/Core/Private/FIRComponent.h b/Firebase/Core/Private/FIRComponent.h
new file mode 100644
index 0000000..cb51ee7
--- /dev/null
+++ b/Firebase/Core/Private/FIRComponent.h
@@ -0,0 +1,91 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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.
+ */
+
+#import <Foundation/Foundation.h>
+
+@class FIRApp;
+@class FIRComponentContainer;
+
+NS_ASSUME_NONNULL_BEGIN
+
+/// Provides a system to clean up cached instances returned from the component system.
+NS_SWIFT_NAME(ComponentLifecycleMaintainer)
+@protocol FIRComponentLifecycleMaintainer
+/// The associated app will be deleted, clean up any resources as they are about to be deallocated.
+- (void)appWillBeDeleted:(FIRApp *)app;
+@end
+
+typedef _Nullable id (^FIRComponentCreationBlock)(FIRComponentContainer *container,
+                                                  BOOL *isCacheable)
+    NS_SWIFT_NAME(ComponentCreationBlock);
+
+@class FIRDependency;
+
+/// Describes the timing of instantiation. Note: new components should default to lazy unless there
+/// is a strong reason to be eager.
+typedef NS_ENUM(NSInteger, FIRInstantiationTiming) {
+  FIRInstantiationTimingLazy,
+  FIRInstantiationTimingAlwaysEager,
+  FIRInstantiationTimingEagerInDefaultApp
+} NS_SWIFT_NAME(InstantiationTiming);
+
+/// A component that can be used from other Firebase SDKs.
+NS_SWIFT_NAME(Component)
+@interface FIRComponent : NSObject
+
+/// The protocol describing functionality provided from the Component.
+@property(nonatomic, strong, readonly) Protocol *protocol;
+
+/// The timing of instantiation.
+@property(nonatomic, readonly) FIRInstantiationTiming instantiationTiming;
+
+/// An array of dependencies for the component.
+@property(nonatomic, copy, readonly) NSArray<FIRDependency *> *dependencies;
+
+/// A block to instantiate an instance of the component with the appropriate dependencies.
+@property(nonatomic, copy, readonly) FIRComponentCreationBlock creationBlock;
+
+// There's an issue with long NS_SWIFT_NAMES that causes compilation to fail, disable clang-format
+// for the next two methods.
+// clang-format off
+
+/// Creates a component with no dependencies that will be lazily initialized.
++ (instancetype)componentWithProtocol:(Protocol *)protocol
+                        creationBlock:(FIRComponentCreationBlock)creationBlock
+NS_SWIFT_NAME(init(_:creationBlock:));
+
+/// Creates a component to be registered with the component container.
+///
+/// @param protocol - The protocol describing functionality provided by the component.
+/// @param instantiationTiming - When the component should be initialized. Use .lazy unless there's
+///                              a good reason to be instantiated earlier.
+/// @param dependencies - Any dependencies the `implementingClass` has, optional or required.
+/// @param creationBlock - A block to instantiate the component with a container, and if
+/// @return A component that can be registered with the component container.
++ (instancetype)componentWithProtocol:(Protocol *)protocol
+                  instantiationTiming:(FIRInstantiationTiming)instantiationTiming
+                         dependencies:(NSArray<FIRDependency *> *)dependencies
+                        creationBlock:(FIRComponentCreationBlock)creationBlock
+NS_SWIFT_NAME(init(_:instantiationTiming:dependencies:creationBlock:));
+
+// clang-format on
+
+/// Unavailable.
+- (instancetype)init NS_UNAVAILABLE;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Firebase/Core/Private/FIRComponentContainer.h b/Firebase/Core/Private/FIRComponentContainer.h
new file mode 100644
index 0000000..10e2255
--- /dev/null
+++ b/Firebase/Core/Private/FIRComponentContainer.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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.
+ */
+#import <Foundation/Foundation.h>
+
+#import "FIRComponentType.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/// A type-safe macro to retrieve a component from a container. This should be used to retrieve
+/// components instead of using the container directly.
+#define FIR_COMPONENT(type, container) \
+  [FIRComponentType<id<type>> instanceForProtocol:@protocol(type) inContainer:container]
+
+@class FIRApp;
+
+/// A container that holds different components that are registered via the
+/// `registerAsComponentRegistrant:` call. These classes should conform to `FIRComponentRegistrant`
+/// in order to properly register components for Core.
+NS_SWIFT_NAME(FirebaseComponentContainer)
+@interface FIRComponentContainer : NSObject
+
+/// A weak reference to the app that an instance of the container belongs to.
+@property(nonatomic, weak, readonly) FIRApp *app;
+
+/// Unavailable. Use the `container` property on `FIRApp`.
+- (instancetype)init NS_UNAVAILABLE;
+
+/// Register a class to provide components for the interoperability system. The class should conform
+/// to `FIRComponentRegistrant` and provide an array of `FIRComponent` objects.
++ (void)registerAsComponentRegistrant:(Class)klass;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Firebase/Core/Private/FIRComponentContainerInternal.h b/Firebase/Core/Private/FIRComponentContainerInternal.h
new file mode 100644
index 0000000..bb73e7b
--- /dev/null
+++ b/Firebase/Core/Private/FIRComponentContainerInternal.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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.
+ */
+#import <Foundation/Foundation.h>
+
+#import "FIRComponent.h"
+#import "FIRComponentContainer.h"
+
+@class FIRApp;
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface FIRComponentContainer (Private)
+
+/// Initializes a contain for a given app. This should only be called by the app itself.
+- (instancetype)initWithApp:(FIRApp *)app;
+
+/// Retrieves an instance that conforms to the specified protocol. This will return `nil` if the
+/// protocol wasn't registered, or if the instance couldn't instantiate for the provided app.
+- (nullable id)instanceForProtocol:(Protocol *)protocol NS_SWIFT_NAME(instance(for:));
+
+/// Remove all of the cached instances stored and allow them to clean up after themselves.
+- (void)removeAllCachedInstances;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Firebase/Core/Private/FIRComponentRegistrant.h b/Firebase/Core/Private/FIRComponentRegistrant.h
new file mode 100644
index 0000000..ad2cad2
--- /dev/null
+++ b/Firebase/Core/Private/FIRComponentRegistrant.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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.
+ */
+
+#ifndef FIRComponentRegistrant_h
+#define FIRComponentRegistrant_h
+
+#import <Foundation/Foundation.h>
+
+@class FIRComponent;
+
+NS_ASSUME_NONNULL_BEGIN
+
+/// Describes functionality for SDKs registering components in the `FIRComponentContainer`.
+NS_SWIFT_NAME(ComponentRegistrant)
+@protocol FIRComponentRegistrant
+
+/// Returns one or more FIRComponents that will be registered in
+/// FIRApp and participate in dependency resolution and injection.
++ (NSArray<FIRComponent *> *)componentsToRegister;
+
+@end
+
+NS_ASSUME_NONNULL_END
+
+#endif /* FIRComponentRegistrant_h */
diff --git a/Firebase/Core/Private/FIRComponentType.h b/Firebase/Core/Private/FIRComponentType.h
new file mode 100644
index 0000000..3254835
--- /dev/null
+++ b/Firebase/Core/Private/FIRComponentType.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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.
+ */
+
+#import <Foundation/Foundation.h>
+
+@class FIRComponentContainer;
+
+NS_ASSUME_NONNULL_BEGIN
+
+/// Do not use directly. A placeholder type in order to provide a macro that will warn users of
+/// mis-matched protocols.
+NS_SWIFT_NAME(ComponentType)
+@interface FIRComponentType <__covariant T> : NSObject
+
+/// Do not use directly. A factory method to retrieve an instance that provides a specific
+/// functionality.
++ (T)instanceForProtocol:(Protocol *)protocol
+             inContainer:(FIRComponentContainer *)container;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Firebase/Core/Private/FIRCoreConfigurable.h b/Firebase/Core/Private/FIRCoreConfigurable.h
new file mode 100644
index 0000000..6c2b077
--- /dev/null
+++ b/Firebase/Core/Private/FIRCoreConfigurable.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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.
+ */
+
+#ifndef FIRCoreConfigurable_h
+#define FIRCoreConfigurable_h
+
+#import <Foundation/Foundation.h>
+
+@class FIRApp;
+
+NS_ASSUME_NONNULL_BEGIN
+
+/// Provides an interface to set up an SDK once a `FIRApp` is configured.
+NS_SWIFT_NAME(CoreConfigurable)
+@protocol FIRCoreConfigurable
+
+/// Configure the SDK if needed ahead of time. This method is called when the developer calls
+/// `FirebaseApp.configure()`.
++ (void)configureWithApp:(FIRApp *)app;
+
+@end
+
+NS_ASSUME_NONNULL_END
+
+#endif /* FIRCoreConfigurable_h */
diff --git a/Firebase/Core/Private/FIRDependency.h b/Firebase/Core/Private/FIRDependency.h
new file mode 100644
index 0000000..46e9b7e
--- /dev/null
+++ b/Firebase/Core/Private/FIRDependency.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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.
+ */
+
+#import <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+/// A dependency on a specific protocol's functionality.
+NS_SWIFT_NAME(Dependency)
+@interface FIRDependency : NSObject
+
+/// The protocol describing functionality being depended on.
+@property(nonatomic, strong, readonly) Protocol *protocol;
+
+/// A flag to specify if the dependency is required or not.
+@property(nonatomic, readonly) BOOL isRequired;
+
+/// Initializes a dependency that is required. Calls `initWithProtocol:isRequired` with `YES` for
+/// the required parameter.
+/// Creates a required dependency on the specified protocol's functionality.
++ (instancetype)dependencyWithProtocol:(Protocol *)protocol;
+
+/// Creates a dependency on the specified protocol's functionality and specify if it's required for
+/// the class's functionality.
++ (instancetype)dependencyWithProtocol:(Protocol *)protocol isRequired:(BOOL)required;
+
+/// Use `dependencyWithProtocol:isRequired:` instead.
+- (instancetype)init NS_UNAVAILABLE;
+
+@end
+
+NS_ASSUME_NONNULL_END