[Opensim-dev] Module/Plugin Loading

[Melanie]

It's called _Mono_ addins... does it work in .NET?

Melanie

Ryan McDougall wrote:
> I've started looking at module/plugin loading in OpenSim. Some have
> commented that the current situation where things are loaded and
> initialized ad hoc should be replaced by a greater use of Mono.Addins.
> 
> In my survey of the code I've identified a lot of copy-paste code, which
> minimally I can remove by consolidating that code into a common class or
> method. However I'd like to try and do a little better, and provide a
> framework for all the ad hoc loading.
> 
> I've identified the following Interfaces which appear to be loaded
> dynamically somewhere:
> 
> 
> ILogData
> IUserData
> IAssetProvider
> IInventoryData
> IApplicationPlugin
> IRegionModule
> IRegionDataStore
> IGridPlugin
> IGridData
> IGenericConfig
> IDataNode
> IDataSnapshotProvider
> IClientNetworkServer
> IPhysicsPlugin
> IMeshingPlugin
> ITerrainEffect
> ITerrainLoader
> ITarget
> 
> Does that look like a comprehensive list?
> Whats the difference between a Plugin and a Module?
> 
> I suggest wrapping Mono.Addins into a simple common loader class as
> follows:
> 
> Extend IPlugin to the following:
> 
> public class PluginInitData {}
> 
> public interface IPlugin : IDispose
> {
>   string Version { get; }
>   string Name { get; }
>   void Initialise (PluginInitData);
> }
> 
> and create:
> 
> PluginLoader : IDispose
> {
>   List<IPlugin> plugins = new List<IPlugin>();
> 
>   PluginLoader (string dir)
>   {            
>     AddPluginDir (dir);
>   }
> 
>   void AddPluginDir (string dir)
>   {
>     AddinManager.Initialize (dir);
>   }
> 
>   void Load (string extpoint, PluginInitData data)
>   {
>     LoadUninitialized (extpoint);
>     Initialize (data);
>   }
> 
>   void LoadUninitialized <T> (string extpoint) where T : IPlugin
>   {
>     AddinManager.Registry.Update (null);
>     ExtensionNodeList ns = AddinManager.GetExtensionNodes(extpoint);
>     foreach (TypeExtensionNode n in ns)
>     {
>       log.Info("[PLUGINS]: Loading plugin " + n.Path);
>       plugins.Add ((T) n.CreateInstance());
>     }
>   }
> 
>   void Initialize (PluginInitData data)
>   {
>     foreach (IPlugin p in plugins)
>       p.Initialize (data);
>   }
> 
>   void Dispose ()
>   {
>     foreach (IPlugin p in plugins)
>     p.Dispose ();
>   }
> }
> 
> Which would be used in the following way:
> 
> 1. Plugins would be created this way
> 
> class MyPluginInitData : PluginInitData
> {
>   int foo;
>   string bar;
> };
> 
> class MyPlugin : IPlugin
> {
>   Initialize (PluginInitData data)
>   {
>     MyPluginInitData d = data as MyPluginInitData;
>     //...
>   }
>   //...
> }
> 
> 2. And would be loaded this way:
> 
> PluginLoader loader = new PluginLoader ("my/plugin/dir");
> MyPluginInitData data = new MyPluginInitData (42, "huzzah");
> 
> loader.load ("/OpenSim/MyPlugins", data);
> 
> Whozit w = new Whozit();
> w.lart (loader.plugins); // does stuff with plugins
> 
> What do you think?
> 
> 
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