pa_mute

#!/usr/bin/env python2
# -*- coding: utf-8 -*-
from __future__ import print_function

import os, sys, string, re, time


def dbus_bytes(dbus_arr, strip='\0' + string.whitespace):
	return bytes(bytearray(dbus_arr).strip(strip))

def dbus_prop(obj, iface, k, v=None):
	kws = dict(dbus_interface='org.freedesktop.DBus.Properties')
	if v is None: return obj.Get(iface, k, **kws)
	else: return obj.Set(iface, k, v, **kws)

def get_bus(srv_addr=None):
	import dbus
	if srv_addr is None:
		srv_addr = os.environ.get('PULSE_DBUS_SERVER')
		if not srv_addr\
				and os.access('/run/pulse/dbus-socket', os.R_OK | os.W_OK):
			# Well-known system-wide daemon socket
			srv_addr = 'unix:path=/run/pulse/dbus-socket'
		if not srv_addr:
			srv_addr = dbus_prop(
				dbus.SessionBus()\
					.get_object('org.PulseAudio1', '/org/pulseaudio/server_lookup1'),
				'org.PulseAudio.ServerLookup1', 'Address' )
	return dbus.connection.Connection(srv_addr)

def _mute_pid(pid, srv_addr=None):
	bus = get_bus(srv_addr=srv_addr)
	streams = dbus_prop(
		bus.get_object(object_path='/org/pulseaudio/core1'),
		'org.PulseAudio.Core1', 'PlaybackStreams' )
	if not streams: return None
	streams = list(bus.get_object(object_path=path) for path in streams)
	for stream in streams:
		stream_props = dbus_prop(stream, 'org.PulseAudio.Core1.Stream', 'PropertyList')
		stream_pid = int(dbus_bytes(stream_props['application.process.id']))
		if stream_pid == pid:
			muted = dbus_prop(stream, 'org.PulseAudio.Core1.Stream', 'Mute')
			dbus_prop(stream, 'org.PulseAudio.Core1.Stream', 'Mute', not muted)

child_ctl = None
def mute_pid(pid, srv_addr=None, dbus_reuse=False, bs=1024):
	if dbus_reuse:
		return _mute_pid(pid, srv_addr=srv_addr)

	# Forking here is to prevent dbus module from keeping state,
	#  which seem to prevent it from working on any pulseaudio hiccup
	global child_ctl
	if child_ctl: os.close(child_ctl)
	(r1,w1), (r2,child_ctl) = os.pipe(), os.pipe()
	child_pid, track = os.fork(), None
	if child_pid: # parent
		os.close(w1), os.close(r2)
		try:
			track = os.read(r1, bs + 1)
			os.close(r1)
			os.write(child_ctl, 'x')
		except (OSError, IOError): pass
		try: os.waitpid(child_pid, 0)
		except OSError: pass
	else: # child
		os.close(r1), os.close(child_ctl)
		try:
			track = _mute_pid(pid, srv_addr=srv_addr)
			os.write(w1, track or '\0')
			assert os.read(r2, 1) == 'x'
		except Exception as err:
			raise
			log.warn('Failed to query pa via dbus: %s', err)
		os._exit(0)
	return track if track and track != '\0' else None


def main(args=None):
	import argparse
	parser = argparse.ArgumentParser(
		description='Mutes pluseaudio stream, corresponding to specified process id (pid).')
	parser.add_argument('pid', type=int, help='Process id to mute.')
	parser.add_argument('--debug', action='store_true', help='Verbose operation mode.')
	opts = parser.parse_args(sys.argv[1:] if args is None else args)

	global log
	import logging
	logging.basicConfig(level=logging.DEBUG if opts.debug else logging.WARNING)
	log = logging.getLogger()

	mute_pid(opts.pid, dbus_reuse=True)

if __name__ == '__main__': sys.exit(main())