Merge branch '917-event-based-pulseaudio'

fixes #917

bumblebee_status/modules/core/pulseaudio.py

@@ -33,12 +33,18 @@ Requires the following executable:
 """
 
 import re
+import os
+import time
 import logging
 import functools
+import threading
+import subprocess
+import select
 
 import core.module
 import core.widget
 import core.input
+import core.event
 
 import util.cli
 import util.graph
@@ -103,6 +109,36 @@ class Module(core.module.Module):
         for event in events:
             core.input.register(self, button=event["button"], cmd=event["action"])
 
+        self.__monitor = threading.Thread(target=self.__subscribe, args=())
+        self.__monitor.start()
+
+    def __subscribe(self):
+        self.update2()
+        core.event.trigger("update", [self.id], redraw_only=True)
+        try:
+            proc = subprocess.Popen("pactl subscribe",
+                stdout = subprocess.PIPE,
+                stderr = subprocess.STDOUT,
+                shell = True
+            )
+        except:
+            return
+        while threading.main_thread().is_alive():
+            r, w, e = select.select([proc.stdout], [], [], 1)
+
+            if not (r or w or e):
+                self.update2()
+                core.event.trigger("update", [self.id], redraw_only=True)
+                core.event.trigger("draw")
+                continue # timeout
+            # whateve we got, use it
+            self.update2()
+            core.event.trigger("update", [self.id], redraw_only=True)
+            core.event.trigger("draw")
+            os.set_blocking(proc.stdout.fileno(), False)
+            proc.stdout.read()
+            os.set_blocking(proc.stdout.fileno(), True)
+
     def set_volume(self, amount):
         util.cli.execute(
             "pactl set-{}-{} @DEFAULT_{}@ {}".format(
@@ -200,6 +236,11 @@ class Module(core.module.Module):
         return output
 
     def update(self):
+        if self.__monitor.is_alive():
+            return
+        self.update2()
+
+    def update2(self):
         try:
             self._failed = False
             channel = "sinks" if self._channel == "sink" else "sources"