import logging from twisted.internet import defer log = logging.getLogger(__name__) class EncryptedFileMetadataHandler: def __init__(self, stream_hash, storage, download_manager): self.stream_hash = stream_hash self.storage = storage self.download_manager = download_manager self._final_blob_num = None ######### IMetadataHandler ######### @defer.inlineCallbacks def get_initial_blobs(self): blob_infos = yield self.storage.get_blobs_for_stream(self.stream_hash) formatted_infos = self._format_initial_blobs_for_download_manager(blob_infos) defer.returnValue(formatted_infos) def final_blob_num(self): return self._final_blob_num ######### internal calls ######### def _format_initial_blobs_for_download_manager(self, blob_infos): infos = [] for i, crypt_blob in enumerate(blob_infos): if crypt_blob.blob_hash is not None and crypt_blob.length: infos.append(crypt_blob) else: if i != len(blob_infos) - 1: raise Exception("Invalid stream terminator: %i of %i" % (i, len(blob_infos) - 1)) log.debug("Setting _final_blob_num to %s", str(crypt_blob.blob_num - 1)) self._final_blob_num = crypt_blob.blob_num - 1 return infos