[volume_freebsd] Use spawn.easy_async instead of io.popen

NOTE: Similar to volume_linux, the default mute symbol has also been changed.

Changes.md

@@ -1,6 +1,6 @@
 IMPORTANT:
 
-- `volume_linux` now uses 🔉 and 🔈 instead of ♫ and ♩ to show mute state.
+- `volume` now uses 🔉 and 🔈 instead of ♫ and ♩ to show mute state.
   This BREAKS backward compatibility if users substitute custom symbols
   from these default.
 
@@ -16,7 +16,7 @@ Added:
 
 Fixed:
 
-- [volume_linux] Deprecate `io.popen`
+- [volume] Deprecate `io.popen`
 - [mpd] Lua 5.3 compatibility (for real this time); also correct a typo
 - [pkg,weather,contrib/btc] Allow function call without Awesome
 - [pkg] Use more updated front-ends for Debian/Ubuntu (apt) and Fedora (dnf)

widgets/volume_freebsd.lua

@@ -1,9 +1,8 @@
 -- {{{ Grab environment
 local tonumber = tonumber
-local io = { popen = io.popen }
-local setmetatable = setmetatable
 local string = { match = string.match }
-local helpers = require("vicious.helpers")
+local helpers = require"vicious.helpers"
+local spawn = require"vicious.spawn"
 -- }}}
 
 
@@ -13,26 +12,20 @@ local volume_freebsd = {}
 
 
 -- {{{ Volume widget type
-local function worker(format, warg)
-    if not warg then return end
+local STATE = { on = '🔉', off = '🔈' }
 
-    local mixer_state = { "♫", "♩" }
-
-    -- Get mixer control contents
-    f = io.popen("mixer -s " .. helpers.shellquote(warg))
-    local mixer = f:read()
-    f:close()
-
-    -- Capture mixer control state:          [5%] ... ... [on]
-    local voll, volr = string.match(mixer, "([%d]+):([%d]+)$")
-
-    if voll == "0" and volr == "0" then
-        return {0, 0, mixer_state[2]}
-    else
-        return {voll, volr, mixer_state[1]}
-    end
+local function parse(stdout, stderr, exitreason, exitcode)
+    -- Capture mixer control state, e.g.       42   :  42
+    local voll, volr = string.match(stdout, "([%d]+):([%d]+)$")
+    if voll == "0" and volr == "0" then return { 0, 0, STATE.off } end
+    return { tonumber(voll), tonumber(volr), STATE.on }
+end
 
+function volume_freebsd.async(format, warg, callback)
+    if not warg then return callback{} end
+    spawn.easy_async("mixer -s " .. helpers.shellquote(warg),
+                     function (...) callback(parse(...)) end)
 end
 -- }}}
 
-return setmetatable(volume_freebsd, { __call = function(_, ...) return worker(...) end })
+return helpers.setasyncall(volume_freebsd)

widgets/volume_linux.lua

@@ -4,6 +4,7 @@
 ---------------------------------------------------
 
 -- {{{ Grab environment
+local type = type
 local tonumber = tonumber
 local string = { match = string.match }
 local table  = { concat = table.concat }