Create class GIDUserAuth (#177)

* Create class GIDUserAuth

Add class GIDUserAuth to represent the outcome of a successful signIn or addScopes flow.

GoogleSignIn/Sources/GIDUserAuth.m

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2021 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 "GoogleSignIn/Sources/Public/GoogleSignIn/GIDUserAuth.h"
+
+#import "GoogleSignIn/Sources/GIDUserAuth_Private.h"
+#import "GoogleSignIn/Sources/Public/GoogleSignIn/GIDGoogleUser.h"
+
+@implementation GIDUserAuth
+
+- (instancetype)initWithGoogleUser:(GIDGoogleUser *)user
+                    serverAuthCode:(nullable NSString *)serverAuthCode {
+  self = [super init];
+  if (self) {
+    _user = user;
+    _serverAuthCode = serverAuthCode;
+  }
+  
+  return self;
+}
+
+@end

GoogleSignIn/Sources/GIDUserAuth_Private.h

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2021 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 "GoogleSignIn/Sources/Public/GoogleSignIn/GIDUserAuth.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+// Private |GIDUserAuth| methods that are used in this SDK.
+@interface GIDUserAuth ()
+
+// Private initializer for |GIDUserAuth|.
+// @param user The current GIDGoogleUser.
+// @param severAuthCode The one-time authorization code for backend to exchange
+//     access and refresh tokens.
+- (instancetype)initWithGoogleUser:(GIDGoogleUser *)user
+                    serverAuthCode:(nullable NSString *)serverAuthCode;
+
+@end
+
+NS_ASSUME_NONNULL_END

GoogleSignIn/Sources/Public/GoogleSignIn/GIDUserAuth.h

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+/*
+* Copyright 2021 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/Foundation.h>
+
+@class GIDGoogleUser;
+
+NS_ASSUME_NONNULL_BEGIN
+
+/// A helper object that contains the outcome of a successful signIn or addScopes flow.
+@interface GIDUserAuth : NSObject
+
+/// The updated `GIDGoogleUser` instance for the user who just completed the flow.
+@property(nonatomic, readonly) GIDGoogleUser *user;
+
+/// An OAuth2 authorization code for the home server.
+@property(nonatomic, readonly, nullable) NSString *serverAuthCode;
+
+/// Unsupported.
++ (instancetype)new NS_UNAVAILABLE;
+
+/// Unsupported.
+- (instancetype)init NS_UNAVAILABLE;
+
+@end
+
+NS_ASSUME_NONNULL_END