private async Task <Assembly?> LoadAssemblyByNameAsync(
AssemblyName assemblyName,
AssemblyLoaderContext?context)
{
if (_assemblyLoadContext == null)
{
return(null);
}
IAssemblyComparer comparer = GetAssemblyNameComparer(assemblyName);
if (TryGetAlreadyLoadedAssembly(assemblyName, comparer, out var alreadyLoadedAssembly))
{
return(alreadyLoadedAssembly);
}
if (TryGetAlreadyLoadingAssembly(assemblyName, comparer, out var assemblyLoadingTask))
{
Debug.WriteLine($"Waiting for Loading Assembly '{assemblyName}'");
return(await assemblyLoadingTask !.ConfigureAwait(false));
}
AssemblyLoaderContext contextScope = context == null
? new AssemblyLoaderContext(assemblyName)
: context.NewScope(assemblyName);
Assembly?assembly = await PerformAssemblyLoad(assemblyName, comparer, contextScope).ConfigureAwait(false);
return(assembly);
}
private async Task <Assembly?> ResolveAssembly(
AssemblyName assemblyName,
IAssemblyComparer comparer,
AssemblyLoaderContext context)
{
if (_assemblyLoadContext == null)
{
return(null);
}
// Try loading the assembly by name (this works when the assembly is part of the bootloader, but never used explicitly)
Assembly?assembly = _assemblyLoadContext.Load(assemblyName);
if (assembly != null)
{
return(assembly);
}
AssemblyData?data = await _assemblyDataProvider.GetAssemblyDataAsync(assemblyName, context).ConfigureAwait(false);
if (data == null)
{
Debug.WriteLine($"Failed to resolve Assembly: '{assemblyName}'");
return(null);
}
var dependencies = await ResolveDependencies(assemblyName, data, context).ConfigureAwait(false);
if (dependencies == null)
{
return(null);
}
return(_assemblyLoadContext.Load(data));
}
public Assembly?GetLoadedAssemblyByName(AssemblyName assemblyName)
{
IAssemblyComparer comparer = GetAssemblyNameComparer(assemblyName);
if (TryGetAlreadyLoadedAssembly(assemblyName, comparer, out var alreadyLoadedAssembly))
{
return(alreadyLoadedAssembly);
}
return(null);
}
private bool TryGetAlreadyLoadingAssembly(
AssemblyName assemblyName,
IAssemblyComparer comparer,
out Task <Assembly?>?assemblyLoadingTask)
{
var assemblyLoadingEntry = _loadingAssemblies
.FirstOrDefault(kv => comparer.Equals(assemblyName, kv.Key));
if (assemblyLoadingEntry.Key == null)
{
assemblyLoadingTask = null;
return(false);
}
assemblyLoadingTask = assemblyLoadingEntry.Value;
return(true);
}
private bool TryGetAlreadyLoadedAssembly(
AssemblyName assemblyName,
IAssemblyComparer comparer,
out Assembly?assembly)
{
if (_assemblyLoadContext == null)
{
assembly = null;
return(false);
}
Assembly?loadedAssembly = _assemblyLoadContext.AllAssemblies
.FirstOrDefault(a => comparer.Equals(assemblyName, a.GetName()));
assembly = loadedAssembly;
return(loadedAssembly != null);
}
private async Task <Assembly?> PerformAssemblyLoad(
AssemblyName assemblyName,
IAssemblyComparer comparer,
AssemblyLoaderContext context)
{
var assemblyLoadingTaskSource = new TaskCompletionSource <Assembly?>();
if (!TryActionRepeteadly(() => _loadingAssemblies.TryAdd(assemblyName, assemblyLoadingTaskSource.Task), 5))
{
throw new InvalidOperationException($"Unable to Load Assembly '{assemblyName}': Concurrency error (adding)");
}
Debug.WriteLine($"Loading Assembly: '{assemblyName}'");
Assembly?assembly = await ResolveAssembly(assemblyName, comparer, context).ConfigureAwait(false);
if (assembly != null)
{
Debug.WriteLine($"Loaded Assembly: '{assemblyName}'");
foreach (var assemblyLoadCallback in _onAssemblyLoad)
{
await assemblyLoadCallback.Invoke(assembly).ConfigureAwait(false);
}
}
else
{
Debug.WriteLine($"Assembly '{assemblyName}' failed to load");
}
assemblyLoadingTaskSource.SetResult(assembly);
if (!TryActionRepeteadly(() => _loadingAssemblies.TryRemove(assemblyName, out var _), 5))
{
throw new InvalidOperationException($"Unable to Load Assembly '{assemblyName}': Concurrency error (removing)");
}
return(assembly);
}
