Initial checkin of gRPC to third_party/

third_party/grpc/src/csharp/Grpc.Auth/GoogleGrpcCredentials.cs

Index: third_party/grpc/src/csharp/Grpc.Auth/GoogleGrpcCredentials.cs
diff --git a/third_party/grpc/src/csharp/Grpc.Auth/GoogleGrpcCredentials.cs b/third_party/grpc/src/csharp/Grpc.Auth/GoogleGrpcCredentials.cs
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+++ b/third_party/grpc/src/csharp/Grpc.Auth/GoogleGrpcCredentials.cs
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+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+using Google.Apis.Auth.OAuth2;
+using Grpc.Core;
+using Grpc.Core.Utils;
+
+namespace Grpc.Auth
+{
+    /// <summary>
+    /// Factory/extension methods to create instances of <see cref="ChannelCredentials"/> and <see cref="CallCredentials"/> classes
+    /// based on credential objects originating from Google auth library.
+    /// </summary>
+    public static class GoogleGrpcCredentials
+    {
+        /// <summary>
+        /// Retrieves an instance of Google's Application Default Credentials using
+        /// <c>GoogleCredential.GetApplicationDefaultAsync()</c> and converts them
+        /// into a gRPC <see cref="ChannelCredentials"/> that use the default SSL credentials.
+        /// </summary>
+        /// <returns>The <c>ChannelCredentials</c> instance.</returns>
+        public static async Task<ChannelCredentials> GetApplicationDefaultAsync()
+        {
+            var googleCredential = await GoogleCredential.GetApplicationDefaultAsync().ConfigureAwait(false);
+            return googleCredential.ToChannelCredentials();
+        }
+
+        /// <summary>
+        /// Creates an instance of <see cref="CallCredentials"/> that will use given access token to authenticate
+        /// with a gRPC service.
+        /// </summary>
+        /// <param name="accessToken">OAuth2 access token.</param>
+        /// /// <returns>The <c>MetadataCredentials</c> instance.</returns>
+        public static CallCredentials FromAccessToken(string accessToken)
+        {
+            return CallCredentials.FromInterceptor(GoogleAuthInterceptors.FromAccessToken(accessToken));
+        }
+
+        /// <summary>
+        /// Converts a <c>ITokenAccess</c> (e.g. <c>GoogleCredential</c>) object
+        /// into a gRPC <see cref="CallCredentials"/> object.
+        /// </summary>
+        /// <param name="credential">The credential to use to obtain access tokens.</param>
+        /// <returns>The <c>CallCredentials</c> instance.</returns>
+        public static CallCredentials ToCallCredentials(this ITokenAccess credential)
+        {
+            return CallCredentials.FromInterceptor(GoogleAuthInterceptors.FromCredential(credential));
+        }
+
+        /// <summary>
+        /// Converts a <c>ITokenAccess</c> (e.g. <c>GoogleCredential</c>) object
+        /// into a gRPC <see cref="ChannelCredentials"/> object.
+        /// Default SSL credentials are used.
+        /// </summary>
+        /// <param name="googleCredential">The credential to use to obtain access tokens.</param>
+        /// <returns>>The <c>ChannelCredentials</c> instance.</returns>
+        public static ChannelCredentials ToChannelCredentials(this ITokenAccess googleCredential)
+        {
+            return ChannelCredentials.Create(new SslCredentials(), googleCredential.ToCallCredentials());
+        }
+    }
+}