Method _read_to_buffer_loop

tornado/iostream.py:730–769

(self)

            raise

    def _read_to_buffer_loop(self) -> Optional[int]:
        # This method is called from _handle_read and _try_inline_read.
        if self._read_bytes is not None:
            target_bytes = self._read_bytes  # type: Optional[int]
        elif self._read_max_bytes is not None:
            target_bytes = self._read_max_bytes
        elif self.reading():
            # For read_until without max_bytes, or
            # read_until_close, read as much as we can before
            # scanning for the delimiter.
            target_bytes = None
        else:
            target_bytes = 0
        next_find_pos = 0
        while not self.closed():
            # Read from the socket until we get EWOULDBLOCK or equivalent.
            # SSL sockets do some internal buffering, and if the data is
            # sitting in the SSL object's buffer select() and friends
            # can't see it; the only way to find out if it's there is to
            # try to read it.
            if self._read_to_buffer() == 0:
                break

            # If we've read all the bytes we can use, break out of
            # this loop.

            # If we've reached target_bytes, we know we're done.
            if target_bytes is not None and self._read_buffer_size >= target_bytes:
                break

            # Otherwise, we need to call the more expensive find_read_pos.
            # It's inefficient to do this on every read, so instead
            # do it on the first read and whenever the read buffer
            # size has doubled.
            if self._read_buffer_size >= next_find_pos:
                pos = self._find_read_pos()
                if pos is not None:
                    return pos
                next_find_pos = self._read_buffer_size * 2
        return self._find_read_pos()

    def _handle_read(self) -> None:
        try: