public void Uninitialise()
{
try
{
lock (m_objLock)
{
if (!IsInitialised())
{
throw new InvalidOperationException("Cannot unitialise plugin assembly; it isn't initialised");
}
// If there are any plugin instances they need tearing down
if (m_dictInstances != null && m_dictInstances.Count > 0)
{
foreach (var instance in m_dictInstances.Values.SelectMany(l => l).Where(l => l.IsInitialised()))
{
instance.Unitialise();
}
}
m_asmManager = null;
try
{
AppDomain.Unload(m_adAssemblyAppDomain);
}
catch (Exception ex)
{
throw new ApplicationException("Failed to unload plugin assembly AppDomain", ex);
}
m_adAssemblyAppDomain = null;
m_bIsInitialised = false;
}
}
catch (Exception ex)
{
throw new ApplicationException("Failed to unitialise plugin assembly", ex);
}
}
/// <summary>
/// Performs initialisation and loads the assembly
/// </summary>
public DistribPluginAssemblyInitialisationResult Initialise()
{
DistribPluginAssemblyInitialisationResult result = new DistribPluginAssemblyInitialisationResult();
try
{
lock (m_objLock)
{
if (IsInitialised())
{
throw new InvalidOperationException("Cannot initialise plugin assembly; it is already initialised");
}
// Set up the AppDomain
m_adAssemblyAppDomain = AppDomain.CreateDomain(Guid.NewGuid() + "_" + m_strAssemblyPath);
try
{
// Create the assembly manager for the plugin assembly isolated in the AppDomain
m_asmManager = (DistribPluginAssemblyManager)m_adAssemblyAppDomain
.CreateInstanceAndUnwrap(
typeof(DistribPluginAssemblyManager).Assembly.FullName,
typeof(DistribPluginAssemblyManager).FullName,
true,
System.Reflection.BindingFlags.CreateInstance,
null,
new object[] { m_strAssemblyPath },
null,
null);
}
catch (Exception ex)
{
throw new ApplicationException("Failed to create manager in AppDomain", ex);
}
if (m_asmManager == null)
{
throw new ApplicationException("Manager in AppDomain was null after creation");
}
try
{
// Load the assembly into the domain
m_asmManager.LoadAssembly();
}
catch (Exception ex)
{
throw new ApplicationException("Manager failed to load assembly into AppDomain", ex);
}
// Retrieve the details for all plugins present in the assembly
// At this point these are the details that should be utilised by the developer and the system
// for *actual* work as they are serialised through the AppDomain and as a result
// any modifications here are not represented in the manager (usability etc)
// When pushing down to the manager to perform low-level work, the type-name is used as the key
// and the plugin details data will simply be used from the version given to the manager.
m_lstPluginDetails = m_asmManager.GetPluginDetails();
if (m_lstPluginDetails == null || m_lstPluginDetails.Count == 0)
{
throw new InvalidOperationException("The plugin assembly contains no Distrib Plugins");
}
// Go through all the plugins in the assembly
foreach (var pluginType in m_lstPluginDetails)
{
// Do any bootstrapping that's required to fill in defaults etc
// This has to be done before checking the usability as it could
// affect things.
var bootstrapResult = _PerformPluginBootstrapping(pluginType);
if (!bootstrapResult.Success)
{
pluginType.MarkAsUnusable(PluginExclusionReason.PluginBootstrapFailure,
bootstrapResult.Result);
result.AddPlugin(pluginType);
continue;
}
// Check over the usability of the plugin and mark it accordingly
var usabilityCheckResult = _CheckUsabilityOfPlugin(pluginType);
if (!usabilityCheckResult.Success)
{
pluginType.MarkAsUnusable(usabilityCheckResult.Result, usabilityCheckResult.ResultTwo);
result.AddPlugin(pluginType);
continue;
}
// Make sure that the additional metadata meets the existence / instancing requirements specified
var metadataConstraintsResult = _CheckAdditionalMetadataExistenceRequirements(pluginType);
if (!metadataConstraintsResult.Success)
{
pluginType.MarkAsUnusable(PluginExclusionReason.PluginAdditionalMetadataConstraintsNotMet,
metadataConstraintsResult.Result);
result.AddPlugin(pluginType);
continue;
}
pluginType.MarkAsUsable();
result.AddPlugin(pluginType);
}
m_bIsInitialised = true;
}
// Lock the result to ensure no modifications
result.LockResult();
return result;
}
catch (ReflectionTypeLoadException ex)
{
// Something has gone wrong when trying to load the types in the plugin
// Mostly owing to missing references / plugins not adhering to interfaces
var loaderExceptions = ex.LoaderExceptions;
var sb = new StringBuilder();
sb.AppendLine("Failed to initialise plugin assembly, type loading errors:");
foreach (var te in loaderExceptions)
{
sb.AppendLine(te.Message);
}
throw new ApplicationException(sb.ToString(), ex);
}
catch (Exception ex)
{
throw new ApplicationException("Failed to initialise plugin assembly", ex);
}
}