[Rollouts] RC interop implementation

FirebaseRemoteConfig.podspec

@@ -53,6 +53,7 @@ app update.
   s.dependency 'FirebaseInstallations', '~> 10.0'
   s.dependency 'GoogleUtilities/Environment', '~> 7.8'
   s.dependency 'GoogleUtilities/NSData+zlib', '~> 7.8'
+  s.dependency 'FirebaseRemoteConfigInterop', '~> 10.19'
 
   s.test_spec 'unit' do |unit_tests|
     unit_tests.scheme = { :code_coverage => true }
@@ -77,7 +78,8 @@ app update.
         'FirebaseRemoteConfig/Tests/Unit/RCNTestUtilities.m',
         'FirebaseRemoteConfig/Tests/Unit/RCNUserDefaultsManagerTests.m',
         'FirebaseRemoteConfig/Tests/Unit/RCNTestUtilities.h',
-        'FirebaseRemoteConfig/Tests/Unit/RCNInstanceIDTest.m'
+        'FirebaseRemoteConfig/Tests/Unit/RCNInstanceIDTest.m',
+        'FirebaseRemoteConfig/Tests/SwiftUnit/*.swift'
     # Supply plist custom plist testing.
     unit_tests.resources =
         'FirebaseRemoteConfig/Tests/Unit/Defaults-testInfo.plist',

FirebaseRemoteConfig/Interop/RemoteConfigInterop.swift

@@ -0,0 +1,21 @@
+// Copyright 2023 Google LLC
+//
+// 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
+
+@objc(FIRRemoteConfigInterop)
+public protocol RemoteConfigInterop {
+  func registerRolloutsStateSubscriber(_ subscriber: RolloutsStateSubscriber?,
+                                       for namespace: String)
+}

FirebaseRemoteConfig/Interop/RolloutAssignment.swift

@@ -0,0 +1,46 @@
+// Copyright 2023 Google LLC
+//
+// 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
+
+@objc(FIRRolloutAssignment)
+public class RolloutAssignment: NSObject {
+  @objc public var rolloutId: String
+  @objc public var variantId: String
+  @objc public var templateVersion: Int64
+  @objc public var parameterKey: String
+  @objc public var parameterValue: String
+
+  public init(rolloutId: String, variantId: String, templateVersion: Int64, parameterKey: String,
+              parameterValue: String) {
+    self.rolloutId = rolloutId
+    self.variantId = variantId
+    self.templateVersion = templateVersion
+    self.parameterKey = parameterKey
+    self.parameterValue = parameterValue
+    super.init()
+  }
+}
+
+@objc(FIRRolloutsState)
+public class RolloutsState: NSObject {
+  @objc public var assignments: Set<RolloutAssignment> = Set()
+
+  public init(assignmentList: [RolloutAssignment]) {
+    for assignment in assignmentList {
+      assignments.insert(assignment)
+    }
+    super.init()
+  }
+}

FirebaseRemoteConfig/Interop/RolloutsStateSubscriber.swift

@@ -0,0 +1,20 @@
+// Copyright 2023 Google LLC
+//
+// 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
+
+@objc(FIRRolloutsStateSubscriber)
+public protocol RolloutsStateSubscriber {
+  func rolloutsStateDidChange(_ rolloutsState: RolloutsState)
+}

FirebaseRemoteConfig/Sources/FIRRemoteConfigComponent.h

@@ -17,6 +17,7 @@
 #import <Foundation/Foundation.h>
 
 #import "FirebaseCore/Extension/FirebaseCoreInternal.h"
+@import FirebaseRemoteConfigInterop;
 
 @class FIRApp;
 @class FIRRemoteConfig;
@@ -37,7 +38,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// A concrete implementation for FIRRemoteConfigInterop to create Remote Config instances and
 /// register with Core's component system.
-@interface FIRRemoteConfigComponent : NSObject <FIRRemoteConfigProvider, FIRLibrary>
+@interface FIRRemoteConfigComponent
+    : NSObject <FIRRemoteConfigProvider, FIRLibrary, FIRRemoteConfigInterop>
 
 /// The FIRApp that instances will be set up with.
 @property(nonatomic, weak, readonly) FIRApp *app;

FirebaseRemoteConfig/Sources/FIRRemoteConfigComponent.m

@@ -24,6 +24,22 @@
 
 @implementation FIRRemoteConfigComponent
 
+static NSMutableDictionary<NSString *, FIRRemoteConfigComponent *> *_componentInstances = nil;
+
++ (FIRRemoteConfigComponent *)getComponentForApp:(FIRApp *)app {
+  @synchronized(_componentInstances) {
+    // need to init the dictionary first
+    if (!_componentInstances) {
+      _componentInstances = [[NSMutableDictionary alloc] init];
+    }
+    if (![_componentInstances objectForKey:app.name]) {
+      _componentInstances[app.name] = [[self alloc] initWithApp:app];
+    }
+    return _componentInstances[app.name];
+  }
+  return nil;
+}
+
 /// Default method for retrieving a Remote Config instance, or creating one if it doesn't exist.
 - (FIRRemoteConfig *)remoteConfigForNamespace:(NSString *)remoteConfigNamespace {
   if (!remoteConfigNamespace) {
@@ -102,9 +118,29 @@ + (void)load {
               creationBlock:^id _Nullable(FIRComponentContainer *container, BOOL *isCacheable) {
                 // Cache the component so instances of Remote Config are cached.
                 *isCacheable = YES;
-                return [[FIRRemoteConfigComponent alloc] initWithApp:container.app];
+                return [FIRRemoteConfigComponent getComponentForApp:container.app];
               }];
-  return @[ rcProvider ];
+
+  // Crashlytics only works on default app, the only shared component between Provider and Interop
+  // is the component for default app
+  FIRComponent *rcInterop = [FIRComponent
+      componentWithProtocol:@protocol(FIRRemoteConfigInterop)
+        instantiationTiming:FIRInstantiationTimingAlwaysEager
+               dependencies:@[]
+              creationBlock:^id _Nullable(FIRComponentContainer *container, BOOL *isCacheable) {
+                // Cache the component so instances of Remote Config are cached.
+                *isCacheable = YES;
+                return [FIRRemoteConfigComponent getComponentForApp:container.app];
+              }];
+  return @[ rcProvider, rcInterop ];
+}
+
+#pragma mark - Remote Config Interop Protocol
+
+- (void)registerRolloutsStateSubscriber:(id<FIRRolloutsStateSubscriber> _Nullable)subscriber
+                                    for:(NSString * _Nonnull)namespace {
+  // TODO(Themisw): Adding the registered subscriber reference to the namespace instance
+  // [self.instances[namespace] addRemoteConfigInteropSubscriber:subscriber];
 }
 
 @end

FirebaseRemoteConfig/Tests/SwiftUnit/RemoteConfigInteropTests.swift

@@ -0,0 +1,65 @@
+// Copyright 2023 Google LLC
+//
+// 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 FirebaseRemoteConfigInterop
+import XCTest
+
+class MockRCInterop: RemoteConfigInterop {
+  weak var subscriber: FirebaseRemoteConfigInterop.RolloutsStateSubscriber?
+  func registerRolloutsStateSubscriber(_ subscriber: FirebaseRemoteConfigInterop
+    .RolloutsStateSubscriber?,
+    for namespace: String) {
+    self.subscriber = subscriber
+  }
+}
+
+class MockRolloutSubscriber: RolloutsStateSubscriber {
+  var isSubscriberCalled = false
+  var rolloutsState: RolloutsState?
+  func rolloutsStateDidChange(_ rolloutsState: FirebaseRemoteConfigInterop.RolloutsState) {
+    isSubscriberCalled = true
+    self.rolloutsState = rolloutsState
+  }
+}
+
+final class RemoteConfigInteropTests: XCTestCase {
+  let rollouts: RolloutsState = {
+    let assignment1 = RolloutAssignment(
+      rolloutId: "rollout_1",
+      variantId: "control",
+      templateVersion: 1,
+      parameterKey: "my_feature",
+      parameterValue: "false"
+    )
+    let assignment2 = RolloutAssignment(
+      rolloutId: "rollout_2",
+      variantId: "enabled",
+      templateVersion: 123,
+      parameterKey: "themis_big_feature",
+      parameterValue: "1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111"
+    )
+    let rollouts = RolloutsState(assignmentList: [assignment1, assignment2])
+    return rollouts
+  }()
+
+  func testRemoteConfigIntegration() throws {
+    let rcSubscriber = MockRolloutSubscriber()
+    let rcInterop = MockRCInterop()
+    rcInterop.registerRolloutsStateSubscriber(rcSubscriber, for: "namespace")
+    rcInterop.subscriber?.rolloutsStateDidChange(rollouts)
+
+    XCTAssertTrue(rcSubscriber.isSubscriberCalled)
+    XCTAssertEqual(rcSubscriber.rolloutsState?.assignments.count, 2)
+  }
+}

FirebaseRemoteConfig/Tests/Unit/FIRRemoteConfigComponentTest.m

@@ -20,6 +20,7 @@
 #import "FirebaseRemoteConfig/Sources/FIRRemoteConfigComponent.h"
 #import "FirebaseRemoteConfig/Sources/Private/FIRRemoteConfig_Private.h"
 #import "FirebaseRemoteConfig/Tests/Unit/RCNTestUtilities.h"
+@import FirebaseRemoteConfigInterop;
 
 @interface FIRRemoteConfigComponentTest : XCTestCase
 @end
@@ -92,7 +93,8 @@ - (void)testInitialization {
 }
 
 - (void)testRegistersAsLibrary {
-  XCTAssertEqual([FIRRemoteConfigComponent componentsToRegister].count, 1);
+  // Now compoment has two register, one is provider and another one is Interop
+  XCTAssertEqual([FIRRemoteConfigComponent componentsToRegister].count, 2);
 
   // Configure a test FIRApp for fetching an instance of the FIRRemoteConfigProvider.
   NSString *appName = [self generatedTestAppName];
@@ -101,12 +103,50 @@ - (void)testRegistersAsLibrary {
 
   // Attempt to fetch the component and verify it's a valid instance.
   id<FIRRemoteConfigProvider> provider = FIR_COMPONENT(FIRRemoteConfigProvider, app.container);
+  id<FIRRemoteConfigInterop> interop = FIR_COMPONENT(FIRRemoteConfigInterop, app.container);
   XCTAssertNotNil(provider);
+  XCTAssertNotNil(interop);
 
   // Ensure that the instance that comes from the container is cached.
   id<FIRRemoteConfigProvider> sameProvider = FIR_COMPONENT(FIRRemoteConfigProvider, app.container);
+  id<FIRRemoteConfigInterop> sameInterop = FIR_COMPONENT(FIRRemoteConfigInterop, app.container);
   XCTAssertNotNil(sameProvider);
+  XCTAssertNotNil(sameInterop);
   XCTAssertEqual(provider, sameProvider);
+  XCTAssertEqual(interop, sameInterop);
+
+  // Dynamic typing, both prototols are refering to the same component instance
+  id providerID = provider;
+  id interopID = interop;
+  XCTAssertEqualObjects(providerID, interopID);
+}
+
+- (void)testTwoAppsCreateTwoComponents {
+  NSString *appName = [self generatedTestAppName];
+  [FIRApp configureWithName:appName options:[self fakeOptions]];
+  FIRApp *app = [FIRApp appNamed:appName];
+
+  [FIRApp configureWithOptions:[self fakeOptions]];
+  FIRApp *defaultApp = [FIRApp defaultApp];
+  XCTAssertNotNil(defaultApp);
+  XCTAssertNotEqualObjects(app, defaultApp);
+
+  id<FIRRemoteConfigProvider> provider = FIR_COMPONENT(FIRRemoteConfigProvider, app.container);
+  id<FIRRemoteConfigInterop> interop = FIR_COMPONENT(FIRRemoteConfigInterop, app.container);
+  id<FIRRemoteConfigProvider> defaultAppProvider =
+      FIR_COMPONENT(FIRRemoteConfigProvider, defaultApp.container);
+  id<FIRRemoteConfigInterop> defaultAppInterop =
+      FIR_COMPONENT(FIRRemoteConfigInterop, defaultApp.container);
+
+  id providerID = provider;
+  id interopID = interop;
+  id defaultAppProviderID = defaultAppProvider;
+  id defaultAppInteropID = defaultAppInterop;
+
+  XCTAssertEqualObjects(providerID, interopID);
+  XCTAssertEqualObjects(defaultAppProviderID, defaultAppInteropID);
+  // Check two apps get their own component to register
+  XCTAssertNotEqualObjects(interopID, defaultAppInteropID);
 }
 
 - (void)testThrowsWithEmptyGoogleAppID {

FirebaseRemoteConfigInterop.podspec

@@ -0,0 +1,29 @@
+Pod::Spec.new do |s|
+  s.name             = 'FirebaseRemoteConfigInterop'
+  s.version          = '10.19.0'
+  s.summary          = 'Interfaces that allow other Firebase SDKs to use Remote Config functionality.'
+
+  s.description      = <<-DESC
+  Not for public use.
+  A set of protocols that other Firebase SDKs can use to interoperate with FirebaseRemoetConfig in a safe
+  and reliable manner.
+                       DESC
+
+  s.homepage         = 'https://firebase.google.com'
+  s.license          = { :type => 'Apache-2.0', :file => 'LICENSE' }
+  s.authors          = 'Google, Inc.'
+
+  # NOTE that these should not be used externally, this is for Firebase pods to depend on each
+  # other.
+  s.source           = {
+    :git => 'https://github.com/firebase/firebase-ios-sdk.git',
+    :tag => 'CocoaPods-' + s.version.to_s
+  }
+  s.social_media_url = 'https://twitter.com/Firebase'
+  s.ios.deployment_target = '11.0'
+  s.osx.deployment_target = '10.13'
+  s.tvos.deployment_target = '12.0'
+  s.watchos.deployment_target = '6.0'
+
+  s.source_files = 'FirebaseRemoteConfig/Interop/*.swift'
+end