/// <summary>
/// It's a hack to manually Dispose Roslyns cache because GC fails with permissions exception.
/// </summary>
/// <remarks>
/// Currently Roslyn's MetadataCache stores AssembliesFromFiles property that stores information about object metadata.
/// But it doesn't clean it, so it will be cleaned by GC. but the problem with GC that it will be executed with lower permissions that it needs
/// AssembliesFromFiles uses WinApi to create MemoryMappedFile
/// </remarks>
private static void TryCleanRoslynCacheHack()
{
if (!SandboxHelper.IsInstanceInsideRunContainer())
{
return;
}
// increase to FullTrust
new PermissionSet(PermissionState.Unrestricted).Assert();
var type = Type.GetType("Roslyn.Compilers.MetadataCache, Roslyn.Compilers");
var property = type.GetProperty("AssembliesFromFiles", BindingFlags.Static | BindingFlags.NonPublic);
var dict = property.GetValue(null) as IDictionary;
if (dict == null)
{
return;
}
if (dict.Count != 0)
{
var caches = dict.Values;
FieldInfo weakReferenceField = null;
PropertyInfo targetProp = null;
foreach (var cache in caches)
{
// init it
if (weakReferenceField == null)
{
weakReferenceField = cache.GetType().GetField("Metadata");
var tmp = weakReferenceField.GetValue(cache);
targetProp = tmp.GetType().GetProperty("Target", BindingFlags.Instance | BindingFlags.NonPublic);
}
var weakReference = weakReferenceField.GetValue(cache);
var obj = targetProp.GetValue(weakReference);
((IDisposable)obj).Dispose();
}
}
dict.Clear();
}
