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/*
* Copyright (c) 2022 Vaughn Nugent
*
* Library: VNLib
* Package: VNLib.Plugins.Runtime
* File: LivePlugin.cs
*
* LivePlugin.cs is part of VNLib.Plugins.Runtime which is part of the larger
* VNLib collection of libraries and utilities.
*
* VNLib.Plugins.Runtime is free software: you can redistribute it and/or modify
* it under the terms of the GNU 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.Runtime 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with VNLib.Plugins.Runtime. If not, see http://www.gnu.org/licenses/.
*/
using System;
using System.Linq;
using System.Reflection;
using System.Text.Json;
using VNLib.Utils.Logging;
using VNLib.Utils.Extensions;
using VNLib.Plugins.Attributes;
namespace VNLib.Plugins.Runtime
{
/// <summary>
/// <para>
/// Wrapper for a loaded <see cref="IPlugin"/> instance, used internally
/// for a single instance.
/// </para>
/// <para>
/// Lifetime: for the existance of a single loaded
/// plugin instance. Created once per loaded plugin instance. Once the plugin
/// is unloaded, it is no longer useable.
/// </para>
/// </summary>
public class LivePlugin : IEquatable<IPlugin>, IEquatable<LivePlugin>
{
/// <summary>
/// The plugin's <see cref="IPlugin.PluginName"/> property during load time
/// </summary>
/// <exception cref="InvalidOperationException"></exception>
public string PluginName => Plugin?.PluginName ?? throw new InvalidOperationException("Plugin is not loaded");
/// <summary>
/// The underlying <see cref="IPlugin"/> that is warpped
/// by he current instance
/// </summary>
public IPlugin? Plugin { get; private set; }
private readonly Type PluginType;
private ConsoleEventHandlerSignature? PluginConsoleHandler;
internal LivePlugin(IPlugin plugin)
{
Plugin = plugin;
PluginType = plugin.GetType();
GetConsoleHandler();
}
private void GetConsoleHandler()
{
//Get the console handler method from the plugin instance
MethodInfo? handler = (from m in PluginType.GetMethods()
where m.GetCustomAttribute<ConsoleEventHandlerAttribute>() != null
select m)
.FirstOrDefault();
//Get a delegate handler for the plugin
PluginConsoleHandler = handler?.CreateDelegate<ConsoleEventHandlerSignature>(Plugin);
}
/// <summary>
/// Sets the plugin's configuration if it defines a <see cref="ConfigurationInitalizerAttribute"/>
/// on an instance method
/// </summary>
/// <param name="hostConfig">The host configuration DOM</param>
/// <param name="pluginConf">The plugin local configuration DOM</param>
internal void InitConfig(JsonDocument hostConfig, JsonDocument pluginConf)
{
//Get the console handler method from the plugin instance
MethodInfo? confHan = PluginType.GetMethods().Where(static m => m.GetCustomAttribute<ConfigurationInitalizerAttribute>() != null)
.FirstOrDefault();
//Get a delegate handler for the plugin
ConfigInitializer? configInit = confHan?.CreateDelegate<ConfigInitializer>(Plugin);
if (configInit == null)
{
return;
}
//Merge configurations before passing to plugin
JsonDocument merged = hostConfig.Merge(pluginConf, "host", PluginType.Name);
try
{
//Invoke
configInit.Invoke(merged);
}
catch
{
merged.Dispose();
throw;
}
}
/// <summary>
/// Invokes the plugin's log initalizer method if it defines a <see cref="LogInitializerAttribute"/>
/// on an instance method
/// </summary>
/// <param name="cliArgs">The current process's CLI args</param>
internal void InitLog(string[] cliArgs)
{
//Get the console handler method from the plugin instance
MethodInfo? logInit = (from m in PluginType.GetMethods()
where m.GetCustomAttribute<LogInitializerAttribute>() != null
select m)
.FirstOrDefault();
//Get a delegate handler for the plugin
LogInitializer? logFunc = logInit?.CreateDelegate<LogInitializer>(Plugin);
//Invoke
logFunc?.Invoke(cliArgs);
}
/// <summary>
/// Invokes the plugins console event handler if the type has one
/// and the plugin is loaded.
/// </summary>
/// <param name="message">The message to pass to the plugin handler</param>
/// <returns>
/// True if the command was sent to the plugin, false if the plugin is
/// unloaded or did not export a console event handler
/// </returns>
public bool SendConsoleMessage(string message)
{
//Make sure plugin is loaded and has a console handler
if (PluginConsoleHandler == null)
{
return false;
}
//Invoke plugin console handler
PluginConsoleHandler(message);
return true;
}
/// <summary>
/// Calls the <see cref="IPlugin.Load"/> method on the plugin if its loaded
/// </summary>
internal void LoadPlugin() => Plugin?.Load();
/// <summary>
/// Unloads all loaded endpoints from
/// that they were loaded to, then unloads the plugin.
/// </summary>
/// <param name="logSink">An optional log provider to write unload exceptions to</param>
/// <remarks>
/// If <paramref name="logSink"/> is no null unload exceptions are swallowed and written to the log
/// </remarks>
internal void UnloadPlugin(ILogProvider? logSink)
{
/*
* We need to swallow plugin unload errors to avoid
* unknown state, making sure endpoints are properly
* unloaded!
*/
try
{
//Unload the plugin
Plugin?.Unload();
}
catch (Exception ex)
{
//Create an unload wrapper for the exception
PluginUnloadException wrapper = new("Exception raised during plugin unload", ex);
if (logSink == null)
{
throw wrapper;
}
//Write error to log sink
logSink.Error(wrapper);
}
Plugin = null;
PluginConsoleHandler = null;
}
///<inheritdoc/>
public override bool Equals(object? obj)
{
Type? pluginType = Plugin?.GetType();
Type? otherType = obj?.GetType();
if(pluginType == null || otherType == null)
{
return false;
}
//If the other plugin is the same type as the current instance return true
return pluginType.FullName == otherType.FullName;
}
///<inheritdoc/>
public bool Equals(LivePlugin? other)
{
return Equals(other?.Plugin);
}
///<inheritdoc/>
public bool Equals(IPlugin? other)
{
return Equals((object?)other);
}
///<inheritdoc/>
public override int GetHashCode()
{
return Plugin?.GetHashCode() ?? throw new InvalidOperationException("Plugin is null");
}
}
}
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