Add FirebaseCore component interoperability. (#1437)

* Add FirebaseCore component interoperability.

This puts in place the system that will allow SDKs to register with
Core and retrieve functionalities provided by other SDKs.

* Updated documentation.

* Add copywrite, fix log messages.

* Explicitly import headers from Private dir

1 files changed, 35 insertions, 0 deletions

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