dio: widget type rewritten

I wrote this module with graphs in mind and returned values were
somewhat hostile towards textbox widgets. Now KB/MB values are
formatted to one decimal point. There is still work to be done.

dio.lua

@@ -5,13 +5,13 @@
 
 -- {{{ Grab environment
 local ipairs = ipairs
-local io = { open = io.open }
 local setmetatable = setmetatable
 local math = { floor = math.floor }
 local table = { insert = table.insert }
+local helpers = require("vicious.helpers")
 local string = {
-    match = string.match,
-    gmatch = string.gmatch
+    gmatch = string.gmatch,
+    format = string.format
 }
 -- }}}
 
@@ -26,28 +26,18 @@ local disk_total = {}
 
 -- {{{ Disk I/O widget type
 local function worker(format, disk)
-    -- Get /proc/diskstats
-    local f = io.open("/proc/diskstats")
     local disk_lines = {}
+    local disk_stats = setmetatable(
+        { _path = "/sys/block/" .. disk },
+        helpers.pathtotable
+    )
 
-    for line in f:lines() do
-        if string.match(line, "("..disk..")%s") then
-            -- Todo: find a way to do this
-            --for stat in string.gmatch(line, "%s([%d]+)") do
-            --    table.insert(disk_lines, stat)
-            --end
-            --
-            -- Skip first two matches
-            local stat = string.gmatch(line, "%s([%d]+)")
-            stat()
-            stat()
-            -- Store the rest
-            for i = 1, 11 do
-                table.insert(disk_lines, stat())
-            end
+    if disk_stats.stat then
+        local match = string.gmatch(disk_stats.stat, "[%s]+([%d]+)")
+        for i = 1, 11 do -- Store disk stats
+            table.insert(disk_lines, match())
         end
     end
-    f:close()
 
     -- Ensure tables are initialized correctly
     while #disk_total < #disk_lines do
@@ -67,8 +57,8 @@ local function worker(format, disk)
     -- Calculate I/O
     disk_usage["{raw}"] = diff_total[7] + diff_total[3]
     -- Divide "sectors read" by 2 and 1024 to get KB and MB
-    disk_usage["{kb}"] = math.floor(diff_total[7] + diff_total[3])/2
-    disk_usage["{mb}"] = math.floor(diff_total[7] + diff_total[3])/1024
+    disk_usage["{kb}"] = string.format("%.1f", math.floor(diff_total[7] + diff_total[3])/2)
+    disk_usage["{mb}"] = string.format("%.1f", math.floor(diff_total[7] + diff_total[3])/1024)
 
     return disk_usage
 end