Managed HTTP transport: allow custom transport

Continue to allow a custom subtransport to override our own.

Author: ethomson

LibGit2Sharp/Core/NativeMethods.cs

@@ -205,8 +205,8 @@ private static void InitializeNativeLibrary()
             // Configure the .NET HTTP(S) mechanism on the first initialization of the library in the current process.
             if (initCounter == 1)
             {
-                httpSubtransportRegistration = GlobalSettings.RegisterSmartSubtransport<ManagedHttpSmartSubtransport>("http");
-                httpsSubtransportRegistration = GlobalSettings.RegisterSmartSubtransport<ManagedHttpSmartSubtransport>("https");
+                httpSubtransportRegistration = GlobalSettings.RegisterDefaultSmartSubtransport<ManagedHttpSmartSubtransport>("http");
+                httpsSubtransportRegistration = GlobalSettings.RegisterDefaultSmartSubtransport<ManagedHttpSmartSubtransport>("https");
             }
         }
 
@@ -217,12 +217,12 @@ private sealed class NativeShutdownObject : CriticalFinalizerObject
             {
                 if (httpSubtransportRegistration != null)
                 {
-                    GlobalSettings.UnregisterSmartSubtransport(httpSubtransportRegistration);
+                    GlobalSettings.UnregisterDefaultSmartSubtransport(httpSubtransportRegistration);
                 }
 
                 if (httpsSubtransportRegistration != null)
                 {
-                    GlobalSettings.UnregisterSmartSubtransport(httpsSubtransportRegistration);
+                    GlobalSettings.UnregisterDefaultSmartSubtransport(httpsSubtransportRegistration);
                 }
 
                 git_libgit2_shutdown();

LibGit2Sharp/GlobalSettings.cs

@@ -22,6 +22,14 @@ public static class GlobalSettings
         private static bool nativeLibraryPathLocked;
         private static string nativeLibraryDefaultPath;
 
+        internal class SmartSubtransportData
+        {
+            internal bool isCustom;
+            internal SmartSubtransportRegistrationData defaultSubtransport;
+        }
+
+        private static readonly Dictionary<string, SmartSubtransportData> smartSubtransportData = new Dictionary<string, SmartSubtransportData>();
+
         static GlobalSettings()
         {
             bool netFX = Platform.IsRunningOnNetFramework();
@@ -79,6 +87,42 @@ public static Version Version
             }
         }
 
+        private static SmartSubtransportData GetOrCreateSmartSubtransportData(string scheme)
+        {
+            Ensure.ArgumentNotNull(scheme, "scheme");
+
+            lock (smartSubtransportData)
+            {
+                if (!smartSubtransportData.ContainsKey(scheme))
+                {
+                    smartSubtransportData[scheme] = new SmartSubtransportData();
+                }
+
+                return smartSubtransportData[scheme];
+            }
+        }
+
+        internal static SmartSubtransportRegistration<T> RegisterDefaultSmartSubtransport<T>(string scheme)
+            where T : SmartSubtransport, new()
+        {
+            Ensure.ArgumentNotNull(scheme, "scheme");
+
+            lock (smartSubtransportData)
+            {
+                var data = GetOrCreateSmartSubtransportData(scheme);
+
+                if (data.defaultSubtransport != null)
+                {
+                    throw new Exception(string.Format("A default subtransport is already configured for {0}", scheme));
+                }
+
+                var registration = RegisterSmartSubtransportInternal<T>(scheme);
+
+                data.defaultSubtransport = registration;
+                return registration;
+            }
+        }
+
         /// <summary>
         /// Registers a new <see cref="SmartSubtransport"/> as a custom
         /// smart-protocol transport with libgit2.  Any Git remote with
@@ -96,8 +140,34 @@ public static Version Version
         public static SmartSubtransportRegistration<T> RegisterSmartSubtransport<T>(string scheme)
             where T : SmartSubtransport, new()
         {
+            SmartSubtransportRegistration<T> registration;
+
             Ensure.ArgumentNotNull(scheme, "scheme");
 
+            lock (smartSubtransportData)
+            {
+                var data = GetOrCreateSmartSubtransportData(scheme);
+
+                if (data.isCustom)
+                {
+                    throw new EntryExistsException(string.Format("A smart subtransport is already registered for {0}", scheme));
+                }
+
+                if (data.defaultSubtransport != null)
+                {
+                    Proxy.git_transport_unregister(scheme);
+                }
+
+                registration = RegisterSmartSubtransportInternal<T>(scheme);
+                data.isCustom = true;
+            }
+
+            return registration;
+        }
+
+        private static SmartSubtransportRegistration<T> RegisterSmartSubtransportInternal<T>(string scheme)
+            where T : SmartSubtransport, new()
+        {
             var registration = new SmartSubtransportRegistration<T>(scheme);
 
             try
@@ -126,6 +196,59 @@ public static void UnregisterSmartSubtransport<T>(SmartSubtransportRegistration<
         {
             Ensure.ArgumentNotNull(registration, "registration");
 
+            var scheme = registration.Scheme;
+
+            lock (smartSubtransportData)
+            {
+                var data = GetOrCreateSmartSubtransportData(scheme);
+
+                if (!data.isCustom)
+                {
+                    throw new NotFoundException(string.Format("No smart subtransport has been registered for {0}", scheme));
+                }
+
+                UnregisterSmartSubtransportInternal(registration);
+
+                data.isCustom = false;
+
+                if (data.defaultSubtransport != null)
+                {
+                    var defaultRegistration = data.defaultSubtransport;
+
+                    Proxy.git_transport_register(defaultRegistration.Scheme,
+                                                 defaultRegistration.FunctionPointer,
+                                                 defaultRegistration.RegistrationPointer);
+                }
+            }
+        }
+
+        internal static void UnregisterDefaultSmartSubtransport<T>(SmartSubtransportRegistration<T> registration)
+            where T : SmartSubtransport, new()
+        {
+            Ensure.ArgumentNotNull(registration, "registration");
+
+            var scheme = registration.Scheme;
+
+            lock (smartSubtransportData)
+            {
+                if (!smartSubtransportData.ContainsKey(scheme))
+                {
+                    throw new Exception(string.Format("No default smart subtransport has been registered for {0}", scheme));
+                }
+
+                if (registration != smartSubtransportData[scheme].defaultSubtransport)
+                {
+                    throw new Exception(string.Format("The given smart subtransport is not the default for {0}", scheme));
+                }
+
+                smartSubtransportData.Remove(scheme);
+                UnregisterSmartSubtransportInternal(registration);
+            }
+        }
+
+        private static void UnregisterSmartSubtransportInternal<T>(SmartSubtransportRegistration<T> registration)
+            where T : SmartSubtransport, new()
+        {
             Proxy.git_transport_unregister(registration.Scheme);
             registration.Free();
         }

LibGit2Sharp/SmartSubtransport.cs

@@ -117,7 +117,7 @@ public int AcquireCredentials(out Credentials cred, string user, params Type[] m
 
             if (credHandle == IntPtr.Zero)
             {
-                throw new InvalidOperationException("creditals callback indicated success but returned no credentials");
+                throw new InvalidOperationException("credentials callback indicated success but returned no credentials");
             }
 
             unsafe

LibGit2Sharp/SmartSubtransportRegistration.cs

@@ -11,7 +11,7 @@ namespace LibGit2Sharp
     /// under a particular scheme (eg "http").
     /// </summary>
     /// <typeparam name="T">The type of SmartSubtransport to register</typeparam>
-    public sealed class SmartSubtransportRegistration<T>
+    public sealed class SmartSubtransportRegistration<T> : SmartSubtransportRegistrationData
         where T : SmartSubtransport, new()
     {
         /// <summary>
@@ -26,15 +26,6 @@ internal SmartSubtransportRegistration(string scheme)
             FunctionPointer = CreateFunctionPointer();
         }
 
-        /// <summary>
-        /// The URI scheme (eg "http") for this transport.
-        /// </summary>
-        public string Scheme { get; private set; }
-
-        internal IntPtr RegistrationPointer { get; private set; }
-
-        internal IntPtr FunctionPointer { get; private set; }
-
         private IntPtr CreateRegistrationPointer()
         {
             var registration = new GitSmartSubtransportRegistration();

LibGit2Sharp/SmartSubtransportRegistrationData.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace LibGit2Sharp
+{
+    /// <summary>
+    /// Information about a smart subtransport registration.
+    /// </summary>
+    public abstract class SmartSubtransportRegistrationData
+    {
+        /// <summary>
+        /// The URI scheme for this transport, for example "http" or "ssh".
+        /// </summary>
+        public string Scheme { get; internal set; }
+
+        internal IntPtr RegistrationPointer { get; set; }
+
+        internal IntPtr FunctionPointer { get; set; }
+    }
+}