pactl: Work around old pactl by a wrapper script

Older versions of pactl, like the one shipped by Debian Bullseye, do not
provide the get-* commands, like get-sink-volume or get-sink-mute. Work
around them by providing a wrapper script for pactl that provides those
commands.

Fixes issue streetturtle#390.

pactl-widget/README.md

@@ -26,6 +26,11 @@ s.mytasklist, -- Middle widget
         },
 ```
 
+**Note.** Older versions of `pactl`, like the one shipped with Debian Bullseye,
+do not provide commands like get-sink-volume or get-sink-mute, which are used
+by this widget. However, a wrapper script `pactl` is provided that augments
+`/usr/bin/pactl` to provide these commands.
+
 ### Shortcuts
 
 To improve responsiveness of the widget when volume level is changed by a shortcut use corresponding methods of the widget:

pactl-widget/pactl

@@ -0,0 +1,30 @@
+#!/bin/sh
+
+PACTL=/usr/bin/pactl
+
+if [ "$1" = "--help" ]; then
+    echo "This is wrapper script around ${PACTL} to provide the commands get-sink-volume"
+    echo "and get-sink-mute if not provided by pactl."
+    echo ""
+    ${PACTL} "${@}"
+fi
+
+# pactl already provides the get-* commands, so plainly call pactl
+if [ -n "$(${PACTL} --help | grep get-)" ]; then
+    $PACTL "${@}"
+fi
+
+CMD=$1
+DEVICE=$2
+
+if [ "${DEVICE}" = "@DEFAULT_SINK@" ]; then
+    DEVICE=$(pactl info | grep "Default Sink:" | sed "s/.*: *//")
+fi
+
+if [ "${CMD}" = "get-sink-volume" ]; then
+    pactl list sinks | grep -E "(Sink #|Name:|^\s*Volume:)" | grep -A2 ${DEVICE} | grep "Volume:" | sed "s/^\s*//"
+fi
+
+if [ "${CMD}" = "get-sink-mute" ]; then
+    pactl list sinks | grep -E "(Sink #|Name:|Mute:)" | grep -A2 ${DEVICE} | grep "Mute:" | sed "s/^\s*//"
+fi