import logging
from twisted.internet import interfaces
from zope.interface import implements

log = logging.getLogger(__name__)


class HashBlobReader_v0(object):
    """
    This is a class that is only used in StreamBlobDecryptor
    and should be deprecated
    """
    implements(interfaces.IConsumer)

    def __init__(self, write_func):
        self.write_func = write_func

    def registerProducer(self, producer, streaming):
        from twisted.internet import reactor

        self.producer = producer
        self.streaming = streaming
        if self.streaming is False:
            reactor.callLater(0, self.producer.resumeProducing)

    def unregisterProducer(self):
        pass

    def write(self, data):
        from twisted.internet import reactor

        self.write_func(data)
        if self.streaming is False:
            reactor.callLater(0, self.producer.resumeProducing)

class HashBlobReader(object):
    """
    This is a file like reader class that supports
    read(size) and close()
    """
    def __init__(self, file_path, finished_cb):
        self.finished_cb = finished_cb
        self.finished_cb_d = None
        self.read_handle = open(file_path, 'rb')

    def __del__(self):
        self.close()

    def read(self, size=-1):
        return self.read_handle.read(size)

    def close(self):
        # if we've already closed and called finished_cb, do nothing
        if self.finished_cb_d is not None:
            return
        self.read_handle.close()
        self.finished_cb_d = self.finished_cb(self)