downloader.py 文件源码

def _check_executor(self, dt):
        start = time()
        try:
            for future in as_completed(self._futures[:], 0):
                self._futures.remove(future)
                try:
                    result = future.result()
                except Exception:
                    traceback.print_exc()
                    # make an error tile?
                    continue
                if result is None:
                    continue
                callback, args = result
                callback(*args)

                # capped executor in time, in order to prevent too much
                # slowiness.
                # seems to works quite great with big zoom-in/out
                if time() - start > self.cap_time:
                    break
        except TimeoutError:
            pass