Class CursorIterator

asyncpg/cursor.py:194–247

class CursorIterator(BaseCursor):

    __slots__ = ('_buffer', '_prefetch', '_timeout')

    def __init__(
        self,
        connection,
        query,
        state,
        args,
        record_class,
        prefetch,
        timeout
    ):
        super().__init__(connection, query, state, args, record_class)

        if prefetch <= 0:
            raise exceptions.InterfaceError(
                'prefetch argument must be greater than zero')

        self._buffer = collections.deque()
        self._prefetch = prefetch
        self._timeout = timeout

    @connresource.guarded
    def __aiter__(self):
        return self

    @connresource.guarded
    async def __anext__(self):
        if self._state is None:
            self._state = await self._connection._get_statement(
                self._query,
                self._timeout,
                named=True,
                record_class=self._record_class,
            )
            self._state.attach()

        if not self._portal_name and not self._exhausted:
            buffer = await self._bind_exec(self._prefetch, self._timeout)
            self._buffer.extend(buffer)

        if not self._buffer and not self._exhausted:
            buffer = await self._exec(self._prefetch, self._timeout)
            self._buffer.extend(buffer)

        if self._portal_name and self._exhausted:
            await self._close_portal(self._timeout)

        if self._buffer:
            return self._buffer.popleft()

        raise StopAsyncIteration


class Cursor(BaseCursor):