| # Copyright 1999-2012 Gentoo Foundation |
| # Distributed under the terms of the GNU General Public License v2 |
| |
| from .PollConstants import PollConstants |
| import select |
| |
| class PollSelectAdapter(object): |
| |
| """ |
| Use select to emulate a poll object, for |
| systems that don't support poll(). |
| """ |
| |
| def __init__(self): |
| self._registered = {} |
| self._select_args = [[], [], []] |
| |
| def register(self, fd, *args): |
| """ |
| Only POLLIN is currently supported! |
| """ |
| if len(args) > 1: |
| raise TypeError( |
| "register expected at most 2 arguments, got " + \ |
| repr(1 + len(args))) |
| |
| eventmask = PollConstants.POLLIN | \ |
| PollConstants.POLLPRI | PollConstants.POLLOUT |
| if args: |
| eventmask = args[0] |
| |
| self._registered[fd] = eventmask |
| self._select_args = None |
| |
| def unregister(self, fd): |
| self._select_args = None |
| del self._registered[fd] |
| |
| def poll(self, *args): |
| if len(args) > 1: |
| raise TypeError( |
| "poll expected at most 2 arguments, got " + \ |
| repr(1 + len(args))) |
| |
| timeout = None |
| if args: |
| timeout = args[0] |
| |
| select_args = self._select_args |
| if select_args is None: |
| select_args = [list(self._registered), [], []] |
| |
| if timeout is not None: |
| select_args = select_args[:] |
| # Translate poll() timeout args to select() timeout args: |
| # |
| # | units | value(s) for indefinite block |
| # ---------|--------------|------------------------------ |
| # poll | milliseconds | omitted, negative, or None |
| # ---------|--------------|------------------------------ |
| # select | seconds | omitted |
| # ---------|--------------|------------------------------ |
| |
| if timeout is not None and timeout < 0: |
| timeout = None |
| if timeout is not None: |
| select_args.append(timeout / 1000) |
| |
| select_events = select.select(*select_args) |
| poll_events = [] |
| for fd in select_events[0]: |
| poll_events.append((fd, PollConstants.POLLIN)) |
| return poll_events |
| |
