[banshee] [HardwareManager] Prepare for gio/udev backend

[Gabriel Burt <gburt src gnome org>]

commit 57461c9ad2d6ea2590099eaace70165271e5b213
Author: Gabriel Burt <gabriel burt gmail com>
Date:   Fri Jul 16 13:04:12 2010 -0700

    [HardwareManager] Prepare for gio/udev backend
    
    Prefer GIO/udev backend over HAL, and share the backend ordering logic
    with the IOProvider.

 src/Backends/Banshee.Hal/Banshee.Hal.addin.xml     |    2 +-
 src/Core/Banshee.Core/Banshee.IO/Provider.cs       |   46 +++++++++-----------
 .../Banshee.Hardware/HardwareManager.cs            |   14 +++---
 3 files changed, 29 insertions(+), 33 deletions(-)
---
diff --git a/src/Backends/Banshee.Hal/Banshee.Hal.addin.xml b/src/Backends/Banshee.Hal/Banshee.Hal.addin.xml
index fd2f2c1..6c1cd2c 100644
--- a/src/Backends/Banshee.Hal/Banshee.Hal.addin.xml
+++ b/src/Backends/Banshee.Hal/Banshee.Hal.addin.xml
@@ -13,7 +13,7 @@
   </Dependencies>
 
   <Extension path="/Banshee/Platform/HardwareManager">
-    <HardwareManager class="Banshee.HalBackend.HardwareManager"/>
+    <HardwareManager class="Banshee.HalBackend.HardwareManager" id="Banshee.HalBackend.HardwareManager" />
   </Extension>
 
 </Addin>
diff --git a/src/Core/Banshee.Core/Banshee.IO/Provider.cs b/src/Core/Banshee.Core/Banshee.IO/Provider.cs
index 16dac3c..345c992 100644
--- a/src/Core/Banshee.Core/Banshee.IO/Provider.cs
+++ b/src/Core/Banshee.Core/Banshee.IO/Provider.cs
@@ -27,6 +27,8 @@
 //
 
 using System;
+using System.Linq;
+using System.Collections.Generic;
 using System.Reflection;
 using Mono.Addins;
 
@@ -42,33 +44,33 @@ namespace Banshee.IO
         private static IDirectory directory;
         private static IFile file;
 
+        public static IEnumerable<TypeExtensionNode> GetOrderedExtensions (string extensionPoint, params string [] ordered_ids)
+        {
+                return AddinManager.GetExtensionNodes (extensionPoint)
+                                   .Cast<TypeExtensionNode> ()
+                                   .Where (n => n.HasId)
+                                   .OrderBy (n => {
+                                       var o = Array.IndexOf (ordered_ids, n.Id);
+                                       return o == -1 ? int.MaxValue : o;
+                                   });
+        }
+
         static Provider () {
             lock (typeof (Provider)) {
                 if (provider != null) {
                     return;
                 }
 
-                TypeExtensionNode best_node = null;
-                int best_index = Int32.MaxValue;
-
-                foreach (TypeExtensionNode node in AddinManager.GetExtensionNodes ("/Banshee/Platform/IOProvider")) {
-                    if (node.HasId) {
-                        if (node.Id == ProviderSchema.Get ()) {
-                            best_node = node;
-                            best_index = -1;
-                        } else {
-                            int idx = Array.IndexOf (builtin_backend_preference, node.Id);
-                            if (idx != -1 && idx < best_index) {
-                                best_index = idx;
-                                best_node = node;
-                            }
-                        }
-                    }
-                }
+                var extensions = GetOrderedExtensions (
+                    "/Banshee/Platform/IOProvider",
+                    ProviderSchema.Get (),
+                    "Banshee.IO.Gio.Provider", "Banshee.IO.Unix.Provider", "Banshee.IO.SystemIO.Provider"
+                );
 
-                if (best_node != null) {
+                foreach (var node in extensions) {
                     try {
-                        provider = (IProvider)best_node.CreateInstance (typeof (IProvider));
+                        provider = (IProvider)node.CreateInstance (typeof (IProvider));
+                        break;
                     } catch (Exception e) {
                         Log.Warning ("IO provider extension failed to load", e.Message);
                     }
@@ -118,12 +120,6 @@ namespace Banshee.IO
             return uri;
         }
 
-        private static string [] builtin_backend_preference = new string [] {
-            "Banshee.IO.Gio.Provider",
-            "Banshee.IO.Unix.Provider",
-            "Banshee.IO.SystemIO.Provider"
-        };
-
         internal static readonly SchemaEntry<string> ProviderSchema = new SchemaEntry<string> (
             "core", "io_provider",
             "Banshee.IO.Gio.Provider",
diff --git a/src/Core/Banshee.Services/Banshee.Hardware/HardwareManager.cs b/src/Core/Banshee.Services/Banshee.Hardware/HardwareManager.cs
index a276d19..d88a7e1 100644
--- a/src/Core/Banshee.Services/Banshee.Hardware/HardwareManager.cs
+++ b/src/Core/Banshee.Services/Banshee.Hardware/HardwareManager.cs
@@ -46,15 +46,15 @@ namespace Banshee.Hardware
 
         public HardwareManager ()
         {
-            foreach (TypeExtensionNode node in AddinManager.GetExtensionNodes ("/Banshee/Platform/HardwareManager")) {
-                try {
-                    if (manager != null) {
-                        throw new Exception (String.Format (
-                            "A HardwareManager has already been loaded ({0}). Only one can be loaded.",
-                            manager.GetType ().FullName));
-                    }
+            var extensions = Banshee.IO.Provider.GetOrderedExtensions (
+                "/Banshee/Platform/HardwareManager",
+                "Banshee.GioBackend.HardwareManager", "Banshee.HalBackend.HardwareManager"
+            );
 
+            foreach (var node in extensions) {
+                try {
                     manager = (IHardwareManager)node.CreateInstance (typeof (IHardwareManager));
+                    break;
                 } catch (Exception e) {
                     Log.Exception ("Hardware manager extension failed to load", e);
                 }