sway: limit volume boost via helper script

Fixes: SIG#22

scripts/sway/notify-volume

@@ -1,30 +0,0 @@
-#!/bin/sh
-
-if ! command -v notify-send >/dev/null || ! command -v pactl > /dev/null; then
-    exit 0;
-fi
-
-# pactl output depends on the current locale
-export LANG=C.UTF-8 LC_ALL=C.UTF-8
-
-SINK=${1:-@DEFAULT_SINK@}
-VOLUME=$(pactl get-sink-volume "$SINK")
-# get first percent value
-VOLUME=${VOLUME%%%*}
-VOLUME=${VOLUME##* }
-
-TEXT="Volume: ${VOLUME}%"
-case $(pactl get-sink-mute "$SINK") in
-    *yes)
-        TEXT="Volume: muted"
-        VOLUME=0
-        ;;
-esac
-
-notify-send \
-    --app-name sway \
-    --expire-time 800 \
-    --hint string:x-canonical-private-synchronous:volume \
-    --hint "int:value:$VOLUME" \
-    --transient \
-    "${TEXT}"

scripts/sway/volume-helper

@@ -0,0 +1,89 @@
+#!/bin/sh
+
+if ! command -v pactl >/dev/null; then
+    exit 0;
+fi
+
+# pactl output depends on the current locale
+export LANG=C.UTF-8 LC_ALL=C.UTF-8
+
+DEFAULT_STEP=5
+LIMIT=${LIMIT:-100}
+SINK="@DEFAULT_SINK@"
+
+clamp() {
+    if [ "$1" -lt 0 ]; then
+        echo "0"
+    elif [ "$1" -gt "$LIMIT" ]; then
+        echo "$LIMIT"
+    else
+        echo "$1"
+    fi
+}
+
+get_sink_volume() { # sink
+    ret=$(pactl get-sink-volume "$1")
+    # get first percent value
+    ret=${ret%%%*}
+    ret=${ret##* }
+    echo "$ret"
+    unset ret
+}
+
+CHANGE=0
+VOLUME=-1
+
+while true; do
+    case $1 in
+        --sink)
+            SINK=${2:-$SINK}
+            shift;;
+        -l|--limit)
+            LIMIT=$((${2:-$LIMIT}))
+            shift;;
+        --set-volume)
+            VOLUME=$(($2))
+            shift;;
+        -i|--increase)
+            CHANGE=$((${2:-$DEFAULT_STEP}))
+            shift;;
+        -d|--decrease)
+            CHANGE=$((-${2:-$DEFAULT_STEP}))
+            shift;;
+        *)
+            break
+            ;;
+    esac
+    shift
+done
+
+if [ "$CHANGE" -ne 0 ]; then
+    VOLUME=$(get_sink_volume "$SINK")
+    VOLUME=$(( VOLUME + CHANGE ))
+    pactl set-sink-volume "$SINK" "$(clamp "$VOLUME")%"
+elif [ "$VOLUME" -ge 0 ]; then
+    pactl set-sink-volume "$SINK" "$(clamp "$VOLUME")%"
+fi
+
+# Display desktop notification
+
+if ! command -v notify-send >/dev/null; then
+    exit 0;
+fi
+
+VOLUME=$(get_sink_volume "$SINK")
+TEXT="Volume: ${VOLUME}%"
+case $(pactl get-sink-mute "$SINK") in
+    *yes)
+        TEXT="Volume: muted"
+        VOLUME=0
+        ;;
+esac
+
+notify-send \
+    --app-name sway \
+    --expire-time 800 \
+    --hint string:x-canonical-private-synchronous:volume \
+    --hint "int:value:$VOLUME" \
+    --transient \
+    "${TEXT}"

sway/config.d/60-bindings-volume.conf

@@ -3,18 +3,19 @@
 #
 # Volume increase/decrease step can be customized by setting the `$volume_step`
 # variable to a numeric value before including the file.
+# Maximum volume boost level can be set with the `$volume_limit` variable.
 #
 # Requires:     pulseaudio-utils
 # Recommends:   libnotify
 
-set $volume_notification_cmd /usr/libexec/sway/notify-volume
+set $volume_helper_cmd /usr/libexec/sway/volume-helper
 
 # Allow volume controls even if the screen is locked
 bindsym --locked {
     XF86AudioRaiseVolume exec \
-        'STEP="$volume_step" && pactl set-sink-volume @DEFAULT_SINK@ +${STEP:-5}% && $volume_notification_cmd'
+        $volume_helper_cmd --limit "$volume_limit" --increase "$volume_step"
     XF86AudioLowerVolume exec \
-        'STEP="$volume_step" && pactl set-sink-volume @DEFAULT_SINK@ -${STEP:-5}% && $volume_notification_cmd'
+        $volume_helper_cmd --limit "$volume_limit" --decrease "$volume_step"
-    XF86AudioMute    exec pactl set-sink-mute @DEFAULT_SINK@ toggle && $volume_notification_cmd
+    XF86AudioMute    exec pactl set-sink-mute @DEFAULT_SINK@ toggle && $volume_helper_cmd
     XF86AudioMicMute exec pactl set-source-mute @DEFAULT_SOURCE@ toggle
 }