On Thu, Sep 14, 2017 at 02:41:12AM +0200, Wojtek Porczyk wrote:
> The intended use is to ensure that the implementation is empty, which is
> one way to ensure that all connections were properly closed and file
> descriptors reclaimed.
>
> Signed-off-by: Wojtek Porczyk <woju@xxxxxxxxxxxxxxxxxxxxxx>
> ---
> libvirtaio.py | 36 ++++++++++++++++++++++++++++++++++--
> 1 file changed, 34 insertions(+), 2 deletions(-)
>
> diff --git a/libvirtaio.py b/libvirtaio.py
> index 97a7f6c..1c432dd 100644
> --- a/libvirtaio.py
> +++ b/libvirtaio.py
> @@ -269,10 +269,27 @@ class virEventAsyncIOImpl(object):
> self.descriptors = DescriptorDict(self)
> self.log = logging.getLogger(self.__class__.__name__)
>
> + # NOTE invariant: _finished.is_set() iff _pending == 0
> + self._pending = 0
> + self._finished = asyncio.Event(loop=loop)
> + self._finished.set()
> +
> def __repr__(self):
> return '<{} callbacks={} descriptors={}>'.format(
> type(self).__name__, self.callbacks, self.descriptors)
>
> + def _pending_inc(self):
> + '''Increase the count of pending affairs. Do not use directly.'''
> + self._pending += 1
> + self._finished.clear()
> +
> + def _pending_dec(self):
> + '''Decrease the count of pending affairs. Do not use directly.'''
> + assert self._pending > 0
> + self._pending -= 1
> + if self._pending == 0:
> + self._finished.set()
> +
> def register(self):
> '''Register this instance as event loop implementation'''
> # pylint: disable=bad-whitespace
> @@ -293,7 +310,20 @@ class virEventAsyncIOImpl(object):
> This is a coroutine.
> '''
> self.log.debug('ff_callback(iden=%d, opaque=...)', iden)
> - return libvirt.virEventInvokeFreeCallback(opaque)
> + ret = libvirt.virEventInvokeFreeCallback(opaque)
> + self._pending_dec()
> + return ret
> +
> + @asyncio.coroutine
> + def drain(self):
> + '''Wait for the implementation to become idle.
> +
> + This is a coroutine.
> + '''
> + self.log.debug('drain()')
> + if self._pending:
> + yield from self._finished.wait()
> + self.log.debug('drain ended')
What is responsible for calling 'drain' ?
>
> def is_idle(self):
> '''Returns False if there are leftovers from a connection
> @@ -301,7 +331,7 @@ class virEventAsyncIOImpl(object):
> Those may happen if there are sematical problems while closing
> a connection. For example, not deregistered events before .close().
> '''
> - return not self.callbacks
> + return not self.callbacks and not self._pending
>
> def _add_handle(self, fd, event, cb, opaque):
> '''Register a callback for monitoring file handle events
> @@ -324,6 +354,7 @@ class virEventAsyncIOImpl(object):
> fd, event, callback.iden)
> self.callbacks[callback.iden] = callback
> self.descriptors[fd].add_handle(callback)
> + self._pending_inc()
> return callback.iden
>
> def _update_handle(self, watch, event):
> @@ -378,6 +409,7 @@ class virEventAsyncIOImpl(object):
> timeout, callback.iden)
> self.callbacks[callback.iden] = callback
> callback.update(timeout=timeout)
> + self._pending_inc()
> return callback.iden
>
> def _update_timeout(self, timer, timeout):
Regards,
Daniel
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