1 files changed, 113 insertions, 0 deletions
diff --git a/src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs b/src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs
new file mode 100644
index 0000000000..f76492cba4
--- /dev/null
+++ b/src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs
@@ -0,0 +1,113 @@
+#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.Runtime.InteropServices;
+using System.Threading;
+using System.Threading.Tasks;
+
+using Grpc.Core.Logging;
+using Grpc.Core.Utils;
+
+namespace Grpc.Core.Internal
+{
+    internal delegate void NativeMetadataInterceptor(IntPtr statePtr, IntPtr serviceUrlPtr, IntPtr callbackPtr, IntPtr userDataPtr, bool isDestroy);
+
+    internal class NativeMetadataCredentialsPlugin
+    {
+        const string GetMetadataExceptionMsg = "Exception occured in metadata credentials plugin.";
+        static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<NativeMetadataCredentialsPlugin>();
+
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern CredentialsSafeHandle grpcsharp_metadata_credentials_create_from_plugin(NativeMetadataInterceptor interceptor);
+        
+        [DllImport("grpc_csharp_ext.dll", CharSet = CharSet.Ansi)]
+        static extern void grpcsharp_metadata_credentials_notify_from_plugin(IntPtr callbackPtr, IntPtr userData, MetadataArraySafeHandle metadataArray, StatusCode statusCode, string errorDetails);
+
+        AsyncAuthInterceptor interceptor;
+        GCHandle gcHandle;
+        NativeMetadataInterceptor nativeInterceptor;
+        CredentialsSafeHandle credentials;
+
+        public NativeMetadataCredentialsPlugin(AsyncAuthInterceptor interceptor)
+        {
+            this.interceptor = Preconditions.CheckNotNull(interceptor, "interceptor");
+            this.nativeInterceptor = NativeMetadataInterceptorHandler;
+
+            // Make sure the callback doesn't get garbage collected until it is destroyed.
+            this.gcHandle = GCHandle.Alloc(this.nativeInterceptor, GCHandleType.Normal);
+            this.credentials = grpcsharp_metadata_credentials_create_from_plugin(nativeInterceptor);
+        }
+
+        public CredentialsSafeHandle Credentials
+        {
+            get { return credentials; }
+        }
+
+        private void NativeMetadataInterceptorHandler(IntPtr statePtr, IntPtr serviceUrlPtr, IntPtr callbackPtr, IntPtr userDataPtr, bool isDestroy)
+        {
+            if (isDestroy)
+            {
+                gcHandle.Free();
+                return;
+            }
+
+            try
+            {
+                string serviceUrl = Marshal.PtrToStringAnsi(serviceUrlPtr);
+                StartGetMetadata(serviceUrl, callbackPtr, userDataPtr);
+            }
+            catch (Exception e)
+            {
+                grpcsharp_metadata_credentials_notify_from_plugin(callbackPtr, userDataPtr, MetadataArraySafeHandle.Create(Metadata.Empty), StatusCode.Unknown, GetMetadataExceptionMsg);
+                Logger.Error(e, GetMetadataExceptionMsg);
+            }
+        }
+
+        private async void StartGetMetadata(string serviceUrl, IntPtr callbackPtr, IntPtr userDataPtr)
+        {
+            try
+            {
+                var metadata = new Metadata();
+                await interceptor(serviceUrl, metadata);
+
+                using (var metadataArray = MetadataArraySafeHandle.Create(metadata))
+                {
+                    grpcsharp_metadata_credentials_notify_from_plugin(callbackPtr, userDataPtr, metadataArray, StatusCode.OK, null);
+                }
+            }
+            catch (Exception e)
+            {
+                grpcsharp_metadata_credentials_notify_from_plugin(callbackPtr, userDataPtr, MetadataArraySafeHandle.Create(Metadata.Empty), StatusCode.Unknown, GetMetadataExceptionMsg);
+                Logger.Error(e, GetMetadataExceptionMsg);
+            }
+        }
+    }
+}