/*
* Copyright (c) 2023 Vaughn Nugent
*
* Library: VNLib
* Package: VNLib.Plugins.Essentials.ServiceStack
* File: ManagedPlugin.cs
*
* ManagedPlugin.cs is part of VNLib.Plugins.Essentials.ServiceStack which is part of the larger
* VNLib collection of libraries and utilities.
*
* VNLib.Plugins.Essentials.ServiceStack is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 2 of the
* License, or (at your option) any later version.
*
* VNLib.Plugins.Essentials.ServiceStack is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see https://www.gnu.org/licenses/.
*/
using System.Linq;
using System.Threading;
using System.Reflection;
using System.ComponentModel.Design;
using VNLib.Utils;
using VNLib.Plugins.Runtime;
using VNLib.Plugins.Attributes;
namespace VNLib.Plugins.Essentials.ServiceStack
{
internal sealed class ManagedPlugin : VnDisposeable, IManagedPlugin
{
internal RuntimePluginLoader Plugin { get; }
///
public string PluginPath => Plugin.Config.AssemblyFile;
private UnloadableServiceContainer? _services;
public ManagedPlugin(RuntimePluginLoader loader) => Plugin = loader;
///
public IUnloadableServiceProvider Services
{
get
{
Check();
return _services!;
}
}
///
public PluginController Controller
{
get
{
Check();
return Plugin.Controller;
}
}
/*
* Automatically called after the plugin has successfully loaded
* by event handlers below
*/
internal void OnPluginLoaded()
{
//If the service container is defined, dispose
_services?.Dispose();
//Init new service container
_services = new();
//Get types from plugin
foreach (LivePlugin plugin in Plugin.Controller.Plugins)
{
/*
* Get the exposed configurator method if declared,
* it may not be defined.
*/
ServiceConfigurator? callback = plugin.PluginType.GetMethods()
.Where(static m => m.GetCustomAttribute() != null && !m.IsAbstract)
.Select(m => m.CreateDelegate(plugin.Plugin))
.FirstOrDefault();
//Invoke if defined to expose services
callback?.Invoke(_services);
}
}
internal void OnPluginUnloaded()
{
//Cleanup services no longer in use. Plugin is still valid until this method returns
using (_services)
{
//signal service cancel before disposing
_services?.SignalUnload();
}
//Remove ref to services
_services = null;
}
protected override void Free()
{
//Dispose services
_services?.Dispose();
//Dispose loader
Plugin.Dispose();
}
private sealed class UnloadableServiceContainer : ServiceContainer, IUnloadableServiceProvider
{
private readonly CancellationTokenSource _cts;
public UnloadableServiceContainer() : base()
{
_cts = new();
}
///
CancellationToken IUnloadableServiceProvider.UnloadToken => _cts.Token;
///
/// Signals to listensers that the service container will be unloading
///
internal void SignalUnload() => _cts.Cancel();
protected override void Dispose(bool disposing)
{
base.Dispose(disposing);
_cts.Dispose();
}
}
}
}