d59753b98d
git-svn-id: file:///srv/devel/repo-conversion/nusu@59 d2e56fa2-650e-0410-a79f-9358c0239efd
111 lines
4.2 KiB
C#
111 lines
4.2 KiB
C#
#region CPL License
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/*
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Nuclex Framework
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Copyright (C) 2002-2008 Nuclex Development Labs
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This library is free software; you can redistribute it and/or
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modify it under the terms of the IBM Common Public License as
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published by the IBM Corporation; either version 1.0 of the
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License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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IBM Common Public License for more details.
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You should have received a copy of the IBM Common Public
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License along with this library
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*/
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#endregion
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using System;
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using System.Reflection;
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namespace Nuclex.Support.Plugins {
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/// <summary>Integration host for plugins</summary>
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/// <remarks>
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/// This class is created by the party that is interested in loading plugins,
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/// herein referred to as the "plugin user". The plugin host will monitor a
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/// repository and react to any assembly being loaded into that repository by
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/// iterating over all types (as in classes and structures) found in the
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/// assembly and using the employer to do whatever the plugin user intends
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/// to do with the types found in that assembly
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/// </remarks>
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public class PluginHost {
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/// <summary>Initializes a plugin host using a new repository</summary>
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/// <param name="employer">Employer used assess and employ the plugin types</param>
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public PluginHost(Employer employer)
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: this(employer, new PluginRepository()) { }
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/// <summary>Initializes the plugin using an existing repository</summary>
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/// <param name="employer">Employer used assess and employ the plugin types</param>
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/// <param name="repository">Repository in which plugins will be stored</param>
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public PluginHost(Employer employer, PluginRepository repository) {
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this.employer = employer;
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this.repository = repository;
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foreach(Assembly assembly in this.repository.LoadedPlugins)
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employAssemblyTypes(assembly);
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this.repository.AssemblyLoaded += new AssemblyLoadEventHandler(assemblyLoadHandler);
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}
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/// <summary>The repository containing all loaded plugins</summary>
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public PluginRepository Repository {
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get { return this.repository; }
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}
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/// <summary>The employer that is used by this plugin integration host</summary>
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public Employer Employer {
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get { return this.employer; }
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}
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/// <summary>Responds to a new plugin being loaded into the repository</summary>
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/// <param name="sender">Repository into which the assembly was loaded</param>
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/// <param name="arguments">Event arguments; contains the loaded assembly</param>
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private void assemblyLoadHandler(object sender, AssemblyLoadEventArgs arguments) {
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employAssemblyTypes(arguments.LoadedAssembly);
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}
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/// <summary>Employs all employable types in an assembly</summary>
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/// <param name="assembly">Assembly whose types to assess and to employ</param>
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private void employAssemblyTypes(Assembly assembly) {
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// Iterate all types contained in the assembly
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foreach(Type type in assembly.GetTypes()) {
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// We'll ignore abstract and non-public types
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if(!type.IsPublic || type.IsAbstract)
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continue;
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// Types that have been tagged with the [NoPlugin] attribute will be ignored
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object[] attributes = type.GetCustomAttributes(true);
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foreach(object attribute in attributes)
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if(attribute is NoPluginAttribute)
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continue;
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// Type seems to be acceptable, assess and possibly employ it
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try {
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if(this.employer.CanEmploy(type))
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this.employer.Employ(type);
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}
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catch(Exception exception) {
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System.Console.WriteLine(
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"Could not employ " + type.ToString() + ": " + exception.Message
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);
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}
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}
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}
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/// <summary>Employs and manages types in the loaded plugin assemblies</summary>
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private Employer employer;
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/// <summary>Repository containing all plugins loaded, shared with other hosts</summary>
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private PluginRepository repository;
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}
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} // namespace Nuclex.Support.Plugins
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