batsys: import battery widget that uses sysfs

Initial widget code was sent by Benedikt Sauer. After some cleanup it
is ready to go into master. It uses data exposed trough /sys and it is
used in the exact same way as the bat widget (and /proc). This widget
will replace batat and acpitool, it will be moved to contrib and
retired.

README

@@ -165,6 +165,7 @@ vicious.widgets.uptime
 
 vicious.widgets.bat
   - provides state, charge, and remaining time for a requested battery
+    using procfs
   - takes battery ID as an argument, i.e. "BAT0"
   - returns 1st value as state of requested battery, 2nd as charge
     level in percent and 3rd as remaining (charging or discharging)
@@ -177,6 +178,14 @@ vicious.widgets.batat
     level in percent, 3rd as remaining (charging or discharging) time,
     4th as state of the second battery etc.
 
+vicious.widgets.batsys
+  - provides state, charge, and remaining time for a requested battery
+    using sysfs
+  - takes battery ID as an argument, i.e. "BAT0"
+  - returns 1st value as state of requested battery, 2nd as charge
+    level in percent and 3rd as remaining (charging or discharging)
+    time
+
 vicious.widgets.mem
   - provides RAM and Swap usage statistics
   - returns 1st value as memory usage in percent, 2nd as memory usage,

bat.lua

@@ -19,7 +19,7 @@ local string = {
 -- }}}
 
 
--- Bat: provides state, charge, and remaining time for a requested battery
+-- Bat: provides state, charge, and remaining time for a requested battery using procfs
 module("vicious.bat")
 
 

batsys.lua

@@ -0,0 +1,84 @@
+---------------------------------------------------
+-- Licensed under the GNU General Public License v2
+--  * (c) 2009, Adrian C. <anrxc@sysphere.org>
+--  * (c) 2009, Benedikt Sauer <filmor@gmail.com>
+---------------------------------------------------
+
+-- {{{ Grab environment
+local tonumber = tonumber
+local io = { open = io.open }
+local setmetatable = setmetatable
+local string = { format = string.format }
+local math = {
+    min = math.min,
+    floor = math.floor
+}
+-- }}}
+
+
+-- Batsys: provides state, charge, and remaining time for a requested battery using sysfs
+module("vicious.batsys")
+
+
+-- {{{ Battery widget type
+local function worker(format, batid)
+    local battery = setmetatable({}, {__index = function(table, name)
+        local f = io.open("/sys/class/power_supply/"..batid.."/"..name)
+        if f then
+            local s = f:read("*all")
+            f:close()
+            return s
+        end
+    end})
+
+    local battery_state = {
+        ["Full\n"] = "↯",
+        ["Unknown\n"] = "⌁",
+        ["Charged\n"] = "↯",
+        ["Charging\n"] = "+",
+        ["Discharging\n"] = "-"
+    }
+
+    -- Check if the battery is present
+    if not battery.present == "1\n" then
+        return {battery_state["Unknown\n"], 0, "N/A"}
+    end
+
+
+    -- Get state information
+    local state = battery_state[battery.status] or battery_state["Unknown\n"]
+
+    -- Get capacity information
+    if battery.charge_now then
+        remaining, capacity = battery.charge_now, battery.charge_full
+    elseif battery.energy_now then
+        remaining, capacity = battery.energy_now, battery.energy_full
+    else
+        return {battery_state["Unknown\n"], 0, "N/A"}
+    end
+
+    -- Get charge information
+    if battery.current_now then rate = battery.current_now
+    else return {battery_state["Unknown\n"], 0, "N/A"} end
+
+
+    -- Calculate percentage (but work around broken BAT/ACPI implementations)
+    local percent = math.min(math.floor(remaining / capacity * 100), 100)
+
+    -- Calculate remaining (charging or discharging) time
+    if state == "+"then
+        timeleft = (tonumber(capacity) - tonumber(remaining)) / tonumber(rate)
+    elseif state == "-" then
+        timeleft = tonumber(remaining) / tonumber(rate)
+    else
+        return {state, percent, "N/A"}
+    end
+    local hoursleft = math.floor(timeleft)
+    local minutesleft = math.floor((timeleft - hoursleft) * 60 )
+    local time = string.format("%02d:%02d", hoursleft, minutesleft)
+
+    return {state, percent, time}
+end
+-- }}}
+
+setmetatable(_M, { __call = function(_, ...) return worker(...) end })

init.lua

@@ -29,6 +29,7 @@ require("vicious.load")
 require("vicious.uptime")
 require("vicious.bat")
 require("vicious.batat")
+require("vicious.batsys")
 require("vicious.mem")
 require("vicious.fs")
 require("vicious.dio")