Tripod.Sources.SqliteCache.SqliteCachedPhotoSource.EnsureInstance C# (CSharp) Method

        void EnsureInstance ()
        {
            if (instance_create_failed)
                throw new PhotoSourceNotAvailableException ();

            lock (this) {
                if (instance == null) {
                    Type type = null;
                    if (!PhotoSourceInfoManager.Instance.PhotoSourceTypes.TryGetValue (SourceType, out type)) {
                        instance_create_failed = true;
                        UpdateAvailability ();
                        throw new PhotoSourceNotAvailableException ();
                    }
                    instance = Activator.CreateInstance (type) as ICacheablePhotoSource;
                    instance.CacheId = CacheId;
                    instance.WakeUp ();
                    
                    instance.AvailabilityChanged += (s, a) => UpdateAvailability ();
                }
            }
        }