Index: Src/GoogleApis.Auth/OAuth2/IAuthorizationCodeFlow.cs
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+/*
+Copyright 2013 Google Inc
+
+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.
+*/
+
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+using Google.Apis.Auth.OAuth2.Responses;
+using Google.Apis.Auth.OAuth2.Requests;
+using Google.Apis.Util;
+using Google.Apis.Util.Store;
+
+namespace Google.Apis.Auth.OAuth2
+{
+    /// <summary>OAuth 2.0 authorization code flow that manages and persists end-user credentials.</summary>
+    public interface IAuthorizationCodeFlow : IDisposable
+    {
+        /// <summary>Gets the method for presenting the access token to the resource server.</summary>
+        IAccessMethod AccessMethod { get; }
+
+        /// <summary>Gets the clock.</summary>
+        IClock Clock { get; }
+
+        /// <summary>Gets the data store used to store the credentials.</summary>
+        IDataStore DataStore { get; }
+
+        /// <summary>Loads the user's token using the flow's <seealso cref="IDataStore"/>.</summary>
+        /// <param name="userId">User identifier</param>
+        /// <param name="taskCancellationToken">Cancellation token to cancel operation</param>
+        /// <returns>Token response</returns>
+        Task<TokenResponse> LoadToken(string userId, CancellationToken taskCancellationToken);
+
+        /// <summary>Deletes the user's token using the flow's <seealso cref="IDataStore"/>.</summary>
+        /// <param name="userId">User identifier</param>
+        /// <param name="taskCancellationToken">Cancellation token to cancel operation</param>
+        Task DeleteToken(string userId, CancellationToken taskCancellationToken);
+
+        /// <summary>Creates an authorization code request with the specified redirect URI.</summary>
+        AuthorizationCodeRequestUrl CreateAuthorizationCodeRequest(string redirectUri);
+
+        /// <summary>Exchanges code with a token.</summary>
+        /// <param name="userId">User identifier</param>
+        /// <param name="code">Authorization code received from the authorization server</param>
+        /// <param name="redirectUri">Redirect URI which is used in the token request</param>
+        /// <param name="taskCancellationToken">Cancellation token to cancel operation</param>
+        /// <returns>Token response which contains the access token</returns>
+        Task<TokenResponse> ExchangeCodeForToken(string userId, string code, string redirectUri,
+            CancellationToken taskCancellationToken);
+
+        /// <summary>Refreshes an access token using a refresh token.</summary>
+        /// <param name="userId">User identifier</param>
+        /// <param name="refreshToken">Refresh token which is used to get a new access token</param>
+        /// <param name="taskCancellationToken">Cancellation token to cancel operation</param>
+        /// <returns>Token response which contains the access token and the input refresh token</returns>
+        Task<TokenResponse> RefreshToken(string userId, string refreshToken, CancellationToken taskCancellationToken);
+    }
+}