python类poll()的实例源码

def is_connection_dropped(conn):  # Platform-specific
    """
    Returns True if the connection is dropped and should be closed.

    :param conn:
        :class:`httplib.HTTPConnection` object.

    Note: For platforms like AppEngine, this will always return ``False`` to
    let the platform handle connection recycling transparently for us.
    """
    sock = getattr(conn, 'sock', False)
    if sock is False:  # Platform-specific: AppEngine
        return False
    if sock is None:  # Connection already closed (such as by httplib).
        return True

    if not poll:
        if not select:  # Platform-specific: AppEngine
            return False

        try:
            return select([sock], [], [], 0.0)[0]
        except socket.error:
            return True

    # This version is better on platforms that support it.
    p = poll()
    p.register(sock, POLLIN)
    for (fno, ev) in p.poll(0.0):
        if fno == sock.fileno():
            # Either data is buffered (bad), or the connection is dropped.
            return True


# This function is copied from socket.py in the Python 2.7 standard
# library test suite. Added to its signature is only `socket_options`.
# One additional modification is that we avoid binding to IPv6 servers
# discovered in DNS if the system doesn't have IPv6 functionality.

def __init__(self , sockstr , protocol , opts=0 , listenq=50 , 
            sockChmod=0o666):
        self.sock = None
        self.opts = opts
        self.protocol = protocol
        self.listenq = int(listenq)
        self.sockChmod = sockChmod
        self.sockStr = sockstr
        self.poll = select.poll()
        self.emask = select.POLLIN | select.POLLPRI
        self.regLock = threading.Lock()
        self.sockMap = {}
        self.protoMap = {}
        self._close = threading.Event()
    # }}}

    # runAccepts() {{{

def register(self , sock , proto):
        fileno = sock.fileno()
        self.regLock.acquire()
        self.sockMap[fileno] = sock
        self.protoMap[fileno] = proto
        self.poll.register(fileno , self.emask)
        self.regLock.release()
    # }}}

    # unregister() {{{

def unregister(self , fileno):
        self.regLock.acquire()
        self.poll.unregister(fileno)
        del self.sockMap[fileno]
        del self.protoMap[fileno]
        self.regLock.release()
    # }}}

    # run() {{{

def close(self):
        self._close.set()
        for i , s in list(self.sockMap.items()):
            self.poll.unregister(i)
            s.close()
            del self.sockMap[i]
        for i , p in list(self.protoMap.items()):
            p.connectionLost()
            del self.protoMap[i]
        self.sock.close()
    # }}}
# }}}

# class ThreadFactory {{{

def __init__(self):
            super(PollSelector, self).__init__()
            self._poll = select.poll()

def _wrap_poll(self, timeout=None):
            """ Wrapper function for select.poll.poll() so that
            _syscall_wrapper can work with only seconds. """
            if timeout is not None:
                if timeout <= 0:
                    timeout = 0
                else:
                    # select.poll.poll() has a resolution of 1 millisecond,
                    # round away from zero to wait *at least* timeout seconds.
                    timeout = math.ceil(timeout * 1e3)

            result = self._poll.poll(timeout)
            return result

def select(self, timeout=None):
            if timeout is not None:
                if timeout <= 0:
                    timeout = 0.0
                else:
                    # select.epoll.poll() has a resolution of 1 millisecond
                    # but luckily takes seconds so we don't need a wrapper
                    # like PollSelector. Just for better rounding.
                    timeout = math.ceil(timeout * 1e3) * 1e-3
                timeout = float(timeout)
            else:
                timeout = -1.0  # epoll.poll() must have a float.

            # We always want at least 1 to ensure that select can be called
            # with no file descriptors registered. Otherwise will fail.
            max_events = max(len(self._fd_to_key), 1)

            ready = []
            fd_events = _syscall_wrapper(self._epoll.poll, True,
                                         timeout=timeout,
                                         maxevents=max_events)
            for fd, event_mask in fd_events:
                events = 0
                if event_mask & ~select.EPOLLIN:
                    events |= EVENT_WRITE
                if event_mask & ~select.EPOLLOUT:
                    events |= EVENT_READ

                key = self._key_from_fd(fd)
                if key:
                    ready.append((key, events & key.events))
            return ready

def _can_allocate(struct):
    """ Checks that select structs can be allocated by the underlying
    operating system, not just advertised by the select module. We don't
    check select() because we'll be hopeful that most platforms that
    don't have it available will not advertise it. (ie: GAE) """
    try:
        # select.poll() objects won't fail until used.
        if struct == 'poll':
            p = select.poll()
            p.poll(0)

        # All others will fail on allocation.
        else:
            getattr(select, struct)().close()
        return True
    except (OSError, AttributeError) as e:
        return False


# Choose the best implementation, roughly:
# kqueue == epoll > poll > select. Devpoll not supported. (See above)
# select() also can't accept a FD > FD_SETSIZE (usually around 1024)

def is_connection_dropped(conn):  # Platform-specific
    """
    Returns True if the connection is dropped and should be closed.

    :param conn:
        :class:`httplib.HTTPConnection` object.

    Note: For platforms like AppEngine, this will always return ``False`` to
    let the platform handle connection recycling transparently for us.
    """
    sock = getattr(conn, 'sock', False)
    if sock is False:  # Platform-specific: AppEngine
        return False
    if sock is None:  # Connection already closed (such as by httplib).
        return True

    if not poll:
        if not select:  # Platform-specific: AppEngine
            return False

        try:
            return select([sock], [], [], 0.0)[0]
        except socket.error:
            return True

    # This version is better on platforms that support it.
    p = poll()
    p.register(sock, POLLIN)
    for (fno, ev) in p.poll(0.0):
        if fno == sock.fileno():
            # Either data is buffered (bad), or the connection is dropped.
            return True


# This function is copied from socket.py in the Python 2.7 standard
# library test suite. Added to its signature is only `socket_options`.
# One additional modification is that we avoid binding to IPv6 servers
# discovered in DNS if the system doesn't have IPv6 functionality.

def check_output(*popenargs, **kwargs):
    r"""Run command with arguments and return its output as a byte string.

    If the exit code was non-zero it raises a CalledProcessError.  The
    CalledProcessError object will have the return code in the returncode
    attribute and output in the output attribute.

    The arguments are the same as for the Popen constructor.  Example:

    >>> check_output(["ls", "-l", "/dev/null"])
    'crw-rw-rw- 1 root root 1, 3 Oct 18  2007 /dev/null\n'

    The stdout argument is not allowed as it is used internally.
    To capture standard error in the result, use stderr=STDOUT.

    >>> check_output(["/bin/sh", "-c",
    ...               "ls -l non_existent_file ; exit 0"],
    ...              stderr=STDOUT)
    'ls: non_existent_file: No such file or directory\n'
    """
    if 'stdout' in kwargs:
        raise ValueError('stdout argument not allowed, it will be overridden.')
    process = Popen(stdout=PIPE, *popenargs, **kwargs)
    output, unused_err = process.communicate()
    retcode = process.poll()
    if retcode:
        cmd = kwargs.get("args")
        if cmd is None:
            cmd = popenargs[0]
        raise CalledProcessError(retcode, cmd, output=output)
    return output

def poll(self):
        return self._internal_poll()

def poll2(timeout=0.0, map=None):
    # Use the poll() support added to the select module in Python 2.0
    if map is None:
        map = socket_map
    if timeout is not None:
        # timeout is in milliseconds
        timeout = int(timeout*1000)
    pollster = select.poll()
    if map:
        for fd, obj in map.items():
            flags = 0
            if obj.readable():
                flags |= select.POLLIN | select.POLLPRI
            if obj.writable():
                flags |= select.POLLOUT
            if flags:
                # Only check for exceptions if object was either readable
                # or writable.
                flags |= select.POLLERR | select.POLLHUP | select.POLLNVAL
                pollster.register(fd, flags)
        try:
            r = pollster.poll(timeout)
        except select.error, err:
            if err.args[0] != EINTR:
                raise
            r = []
        for fd, flags in r:
            obj = map.get(fd)
            if obj is None:
                continue
            readwrite(obj, flags)

def __init__(self):
            super(PollSelector, self).__init__()
            self._poll = select.poll()

def _wrap_poll(self, timeout=None):
            """ Wrapper function for select.poll.poll() so that
            _syscall_wrapper can work with only seconds. """
            if timeout is not None:
                if timeout <= 0:
                    timeout = 0
                else:
                    # select.poll.poll() has a resolution of 1 millisecond,
                    # round away from zero to wait *at least* timeout seconds.
                    timeout = math.ceil(timeout * 1e3)

            result = self._poll.poll(timeout)
            return result

def select(self, timeout=None):
            if timeout is not None:
                if timeout <= 0:
                    timeout = 0.0
                else:
                    # select.epoll.poll() has a resolution of 1 millisecond
                    # but luckily takes seconds so we don't need a wrapper
                    # like PollSelector. Just for better rounding.
                    timeout = math.ceil(timeout * 1e3) * 1e-3
                timeout = float(timeout)
            else:
                timeout = -1.0  # epoll.poll() must have a float.

            # We always want at least 1 to ensure that select can be called
            # with no file descriptors registered. Otherwise will fail.
            max_events = max(len(self._fd_to_key), 1)

            ready = []
            fd_events = _syscall_wrapper(self._epoll.poll, True,
                                         timeout=timeout,
                                         maxevents=max_events)
            for fd, event_mask in fd_events:
                events = 0
                if event_mask & ~select.EPOLLIN:
                    events |= EVENT_WRITE
                if event_mask & ~select.EPOLLOUT:
                    events |= EVENT_READ

                key = self._key_from_fd(fd)
                if key:
                    ready.append((key, events & key.events))
            return ready

def returncode(self):
        self.process.poll()
        return self.process.returncode

def running(self):
        self.process.poll()
        return self.process.returncode is None

def socket_closed(sock):
    """Return True if we know socket has been closed, False otherwise.
    """
    try:
        if _HAS_POLL:
            _poller.register(sock, _EVENT_MASK)
            rd = _poller.poll(0)
            _poller.unregister(sock)
        else:
            rd, _, _ = select.select([sock], [], [], 0)
    # Any exception here is equally bad (select.error, ValueError, etc.).
    except:
        return True
    return len(rd) > 0

def __init__(self):
            super(PollSelector, self).__init__()
            self._poll = select.poll()