Use procfs to get list of ALSA PCM devices

src/alsainfo.py

@@ -0,0 +1,85 @@
+# -*- coding: utf-8 -*-
+"""Get ALSA card and device list."""
+
+import re
+
+from io import open
+from collections import namedtuple
+from functools import partial
+from os.path import exists
+
+__all__ = (
+    'AlsaCardInfo',
+    'AlsaPcmInfo',
+    'get_cards',
+    'get_capture_devices',
+    'get_playback_devices',
+    'get_pcm_devices'
+)
+
+PROC_CARDS = '/proc/asound/cards'
+PROC_DEVICES = '/proc/asound/pcm'
+
+AlsaCardInfo = namedtuple('AlsaCardInfo', 'card_num id name')
+AlsaPcmInfo = namedtuple('AlsaPcmInfo',
+                         'card_num dev_num id name playback capture')
+
+
+def get_cards():
+    """Get card info from /proc/asound/cards."""
+
+    if not exists(PROC_CARDS):
+        raise IOError("'%s' does not exist. ALSA not loaded?" % PROC_CARDS)
+
+    with open(PROC_CARDS, 'r', encoding='utf-8') as procfile:
+        # capture card number, id and name
+        cardline = re.compile(
+            r'^\s*(?P<num>\d+)\s*'  # card number
+            r'\[(?P<id>\w+)\s*\]:'  # card ID
+            r'.*-\s(?P<name>.*)$')  # card name
+
+        for line in procfile:
+            match = cardline.match(line)
+
+            if match:
+                yield AlsaCardInfo(card_num=int(match.group('num')),
+                                   id=match.group('id').strip(),
+                                   name=match.group('name').strip())
+
+
+def get_pcm_devices():
+    """Get PCM device numbers and names from /proc/asound/pcm."""
+
+    if not exists(PROC_DEVICES):
+        raise IOError("'%s' does not exist. ALSA not loaded?" % PROC_DEVICES)
+
+    with open(PROC_DEVICES, 'r', encoding='utf-8') as procfile:
+        devnum = re.compile(r'(?P<card_num>\d+)-(?P<dev_num>\d+)')
+
+        for line in procfile:
+            fields = [l.strip() for l in line.split(':')]
+
+            if len(fields) >= 3:
+                match = devnum.match(fields[0])
+
+                if match:
+                    yield AlsaPcmInfo(card_num=int(match.group('card_num')),
+                                      dev_num=int(match.group('dev_num')),
+                                      id=fields[1],
+                                      name=fields[2],
+                                      playback='playback 1' in fields,
+                                      capture='capture 1' in fields)
+
+
+def get_devices(playback=True, capture=True):
+    """Return iterable of (device string, card name, device name) tuples."""
+    cards = {c.card_num: c for c in get_cards()}
+
+    for dev in get_pcm_devices():
+        card = cards[dev.card_num]
+        if (playback and dev.playback) or (capture and dev.capture):
+            yield ("hw:%s,%i" % (card.id, dev.dev_num), card.name, dev.name)
+
+
+get_playback_devices = partial(get_devices, capture=False)
+get_capture_devices = partial(get_devices, playback=False)

src/jacksettings.py

@@ -33,6 +33,7 @@ else:
 # ------------------------------------------------------------------------------------------------------------
 # Imports (Custom Stuff)
 
+import alsainfo
 import ui_settings_jack
 
 # ------------------------------------------------------------------------------------------------------------
@@ -700,26 +701,9 @@ class JackSettingsW(QDialog):
     # -----------------------------------------------------------------
     # Helper functions
 
-    def getAlsaDeviceList(self):
-        alsaDeviceList = []
-
-        aplay_out = getoutput("env LANG=C LC_ALL=C aplay -l").split("\n")
-        for line in aplay_out:
-            line = line.strip()
-            if line.startswith("card "):
-                cardInfo  = line.split(", ", 1)[0].split(": ")
-                cardIndex = cardInfo[0].replace("card ", "")
-                cardName  = cardInfo[1].split(" [")[0]
-
-                deviceInfo  = line.split(", ", 1)[1].split(": ")
-                deviceIndex = deviceInfo[0].replace("device ", "")
-                deviceName  = deviceInfo[1].split(" [")[0]
-
-                if cardName != "Loopback":
-                    fullName = "hw:%s,%s [%s]" % (cardName, deviceIndex, deviceName)
-                    alsaDeviceList.append(fullName)
-
-        return alsaDeviceList
+    def getAlsaDeviceList(self, **kwargs):
+        return ["%s [%s - %s]" % dev
+                for dev in alsainfo.get_devices(**kwargs)]
 
     def setComboBoxValue(self, box, text, split=False):
         for i in range(box.count()):
@@ -786,10 +770,10 @@ class JackSettingsW(QDialog):
             self.ui.obj_driver_playback.addItem("none")
 
             if LINUX:
-                dev_list = self.getAlsaDeviceList()
-                for dev in dev_list:
-                    self.ui.obj_driver_capture.addItem(dev)
+                for dev in self.getAlsaDeviceList(capture=False):
                     self.ui.obj_driver_playback.addItem(dev)
+                for dev in self.getAlsaDeviceList(playback=False):
+                    self.ui.obj_driver_capture.addItem(dev)
             else:
                 dev_list = gJackctl.GetParameterConstraint(["driver", "device"])[3]
                 for i in range(len(dev_list)):