/// <summary>
/// Loads the manifest and returns true if it permits the loading of the plugin. If it prohibits
/// the load then <see cref="IgnoredPlugins"/> is updated.
/// </summary>
/// <param name="manifestStorage"></param>
/// <param name="applicationVersion"></param>
/// <param name="dllFileName"></param>
/// <returns></returns>
private bool ManifestAllowsLoad(IPluginManifestStorage manifestStorage, Version applicationVersion, string dllFileName)
{
PluginManifest manifest = null;
try {
manifest = manifestStorage.LoadForPlugin(dllFileName);
if (manifest == null)
{
IgnoredPlugins.Add(dllFileName, Strings.CouldNotFindManifest);
}
} catch (Exception ex) {
IgnoredPlugins.Add(dllFileName, String.Format(Strings.CouldNotParseManifest, ex.Message));
}
bool result = manifest != null;
if (result && !String.IsNullOrEmpty(manifest.MinimumVersion))
{
result = CompareManifestVersions(manifest.MinimumVersion, applicationVersion, dllFileName, true);
}
if (result && !String.IsNullOrEmpty(manifest.MaximumVersion))
{
result = CompareManifestVersions(manifest.MaximumVersion, applicationVersion, dllFileName, false);
}
return(result);
}
/// <summary>
/// See interface docs.
/// </summary>
public void LoadPlugins()
{
var log = Factory.Singleton.Resolve <ILog>().Singleton;
var manifestStorage = Factory.Singleton.Resolve <IPluginManifestStorage>();
var applicationVersion = Factory.Singleton.Resolve <IApplicationInformation>().Version;
var rootFolder = Path.Combine(Provider.ApplicationStartupPath, "Plugins");
if (Provider.DirectoryExists(rootFolder))
{
foreach (var subFolder in Provider.DirectoryGetDirectories(rootFolder))
{
foreach (var dllFileName in Provider.DirectoryGetFiles(subFolder, "VirtualRadar.Plugin.*.dll"))
{
if (ManifestAllowsLoad(manifestStorage, applicationVersion, dllFileName))
{
try {
var pluginTypes = Provider.LoadTypes(dllFileName).Where(t => t.IsClass && typeof(IPlugin).IsAssignableFrom(t)).ToList();
if (pluginTypes.Count != 1)
{
IgnoredPlugins.Add(dllFileName, Strings.PluginDoesNotHaveJustOneIPlugin);
continue;
}
var pluginType = pluginTypes[0];
var plugin = (IPlugin)Activator.CreateInstance(pluginType);
plugin.PluginFolder = subFolder;
var snapshot = Provider.ClassFactoryTakeSnapshot();
try {
plugin.RegisterImplementations(Factory.Singleton);
LoadedPlugins.Add(plugin);
} catch {
Provider.ClassFactoryRestoreSnapshot(snapshot);
throw;
}
} catch (Exception ex) {
var exceptionMessage = FormatException(ex);
Debug.WriteLine(String.Format("PluginManager.LoadPlugins caught exception: {0}", exceptionMessage));
log.WriteLine("Caught exception loading plugin {0}: {1}", dllFileName, exceptionMessage);
IgnoredPlugins.Add(dllFileName, String.Format(Strings.PluginCannotBeLoaded, ex.Message));
}
}
}
}
}
}
private bool CompareManifestVersions(string manifestVersion, Version applicationVersion, string dllFileName, bool isMinimum)
{
bool result = false;
try {
int comparison = VersionComparer.Compare(manifestVersion, applicationVersion);
result = isMinimum ? comparison <= 0 : comparison >= 0;
if (!result)
{
IgnoredPlugins.Add(dllFileName, isMinimum ? String.Format(Strings.PluginMinimumVersionNotMet, manifestVersion) : String.Format(Strings.PluginMaximumVersionNotMet, manifestVersion));
}
} catch {
IgnoredPlugins.Add(dllFileName, isMinimum ? Strings.PluginMinumumVersionUnparseable : Strings.PluginMaximumVersionUnparseable);
}
return(result);
}
