//This attempts to prevent the program from crashing if a plugin throws an exception.
//It is a rather dirty approach and repeated calls will cause a memory leak.
private void PreventPluginCrash(object sender, UnhandledExceptionEventArgs e)
{
StackTrace trace = new StackTrace((Exception)e.ExceptionObject);
foreach (StackFrame frame in trace.GetFrames())
{
Assembly frameAssembly = frame.GetMethod().DeclaringType.Assembly;
if (Plugins.ContainsKey(frameAssembly.GetName().Name))
{
IMSPluginBase plugin = Plugins[frameAssembly.GetName().Name];
Logger.WriteError("An uncaught exception was raised in plugin " + plugin.Name + "! The plugin has been disabled. Error:\n" + e.ExceptionObject);
try
{
plugin.Stop();
}
catch (Exception stopException)
{
Logger.WriteError("During fatal error unload, the plugin's stop method also failed. Exception:\n" + stopException);
}
Plugins.Remove(plugin.Name);
KnownPlugins[plugin.PluginAssembly.GetName().Name].Enabled = false;
Thread.CurrentThread.IsBackground = true;
Thread.CurrentThread.Join(); //suspend the thread indefinitely to stop the CLR from shutting down
}
}
Logger.WriteError("A fatal error occured, resulting in IMS shutting down!\n" + e.ExceptionObject);
}
/// <summary>
/// Attempts to load a plugin into memory from the specified path.
/// </summary>
/// <param name="path">The path of the plugin to load.</param>
/// <returns>The loaded plugin.</returns>
public IMSPluginBase LoadPlugin(string path)
{
IMSPluginBase plugin = LoadPluginAssembly(path);
plugin.Start();
return(plugin);
}
/// <summary>
/// Creates a new instance of the plugin information class using the given plugin.
/// </summary>
/// <param name="plugin">The plugin to gather information about.</param>
public PluginInformation(IMSPluginBase plugin)
{
Name = plugin.Name;
Author = plugin.Author;
Description = plugin.Description;
AssemblyName = plugin.PluginAssemblyName;
FileName = plugin.PluginAssembly.Location;
AssemblyVersion = plugin.CurrentVersion;
Enabled = true;
}
/// <summary>
/// Attempts to remove a plugin from memory. This does not guarantee that the plugin's assembly will be unloaded.
/// </summary>
/// <param name="plugin">The plugin to unload.</param>
public void UnloadPlugin(IMSPluginBase plugin)
{
lock (Locker)
if (Plugins.ContainsKey(plugin.PluginAssemblyName))
{
plugin.Stop();
Plugins.Remove(plugin.PluginAssemblyName);
}
else
{
throw new ArgumentException("This plugin object has not been loaded by the plugin manager.");
}
}
private IMSPluginBase LoadPluginAssembly(string path)
{
lock (Locker)
{
AssemblyLoadContext context = new AssemblyLoadContext(null, true);
Assembly pluginAssembly = context.LoadFromAssemblyPath(path);
try
{
IMSPluginBase plugin = (IMSPluginBase)Activator.CreateInstance(pluginAssembly.GetTypes().Where(x => x.BaseType == typeof(IMSPluginBase)).Single());
Plugins[plugin.PluginAssemblyName] = plugin;
KnownPlugins[plugin.PluginAssemblyName] = new PluginInformation(plugin);
return(plugin);
}
finally
{
context.Unload(); //start context unload now so the assembly disappears once the plugin is gc'd
}
}
}
