contrib: imported Apple PMU battery widget

This code was requested by an iBook G4 owner. Widget type reads
information from /proc/pmu, and takes an argument like "battery_0". It
exposes the same data, in the same way, as all the other battery
widgets.

extra/batpmu.lua

@@ -0,0 +1,78 @@
+---------------------------------------------------
+-- Licensed under the GNU General Public License v2
+--  * (c) 2010, Adrian C. <anrxc@sysphere.org>
+---------------------------------------------------
+
+-- {{{ Grab environment
+local tonumber = tonumber
+local io = { open = io.open }
+local setmetatable = setmetatable
+local math = {
+    min = math.min,
+    floor = math.floor
+}
+local string = {
+    find = string.find,
+    match = string.match,
+    format = string.format
+}
+-- }}}
+
+
+-- Batpmu: provides state, charge and remaining time for a requested battery using PMU
+module("vicious.widgets.batpmu")
+
+
+-- {{{ Battery widget type
+local function worker(format, batid)
+    local battery_state = {
+        ["full"] = "↯",
+        ["unknown"] = "⌁",
+        ["00000013"] = "+",
+        ["00000011"] = "-"
+    }
+
+    -- Get /proc/pmu/battery* state
+    local f = io.open("/proc/pmu/" .. batid)
+    -- Handler for incompetent users
+    if not f then return {battery_state["unknown"], 0, "N/A"} end
+    local statefile = f:read("*all")
+    f:close()
+
+    -- Get /proc/pmu/info data
+    local f = io.open("/proc/pmu/info")
+    local infofile = f:read("*all")
+    f:close()
+
+    -- Check if the battery is present
+    if infofile == nil or string.find(infofile, "Battery count[%s]+:[%s]0") then
+        return {battery_state["unknown"], 0, "N/A"}
+    end
+
+
+    -- Get capacity and charge information
+    local capacity = string.match(statefile, "max_charge[%s]+:[%s]([%d]+).*")
+    local remaining = string.match(statefile, "charge[%s]+:[%s]([%d]+).*")
+
+    -- Calculate percentage
+    local percent = math.min(math.floor(remaining / capacity * 100), 100)
+
+
+    -- Get timer information
+    local timer = string.match(statefile, "time rem%.[%s]+:[%s]([%d]+).*")
+    if timer == "0" then return {battery_state["full"], percent, "N/A"} end
+
+    -- Get state information
+    local state = string.match(statefile, "flags[%s]+:[%s]([%d]+).*")
+    local state = battery_state[state] or battery_state["unknown"]
+
+    -- Calculate remaining (charging or discharging) time
+    local hoursleft = math.floor(tonumber(timer) / 3600)
+    local minutesleft = math.floor((tonumber(timer) / 60) % 60)
+    local time = string.format("%02d:%02d", hoursleft, minutesleft)
+
+    return {state, percent, time}
+end
+-- }}}
+
+setmetatable(_M, { __call = function(_, ...) return worker(...) end })