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{-# LANGUAGE OverloadedStrings #-}

{-| /proc/stat file parser

This module holds the definition of the parser that extracts information

about the CPU load of the system from the @/proc/stat@ file.

-}

{-

Copyright (C) 2013 Google Inc.

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

02110-1301, USA.

-}

module Ganeti.Cpu.LoadParser (cpustatParser) where

import Control.Applicative ((<*>), (<*), (*>), (<$>), (<|>))

import qualified Data.Attoparsec.Text as A

import qualified Data.Attoparsec.Combinator as AC

import Data.Attoparsec.Text (Parser)

import Ganeti.Parsers

import Ganeti.Cpu.Types

-- * Parser implementation

-- | The parser for one line of the CPU status file.

oneCPUstatParser :: Parser CPUstat

oneCPUstatParser =

  let nameP = stringP

      userP = numberP

      niceP = numberP

      systemP = numberP

      idleP = numberP

      iowaitP = numberP

      irqP = numberP

      softirqP = numberP

      stealP = numberP

      guestP = numberP

      guest_niceP = numberP

  in

    CPUstat <$> nameP <*> userP <*> niceP <*> systemP <*> idleP <*> iowaitP

            <*> irqP <*> softirqP <*> stealP <*> guestP <*> guest_niceP

            <* A.endOfLine

-- | When this is satisfied all the lines containing information about

-- the CPU load are parsed.

intrFound :: Parser ()

intrFound = (A.string "intr" *> return ())

             <|> (A.string "page" *> return ())

             <|> (A.string "swap" *> return ())

-- | The parser for the fragment of CPU status file containing

-- information about the CPU load.

cpustatParser :: Parser [CPUstat]

cpustatParser = oneCPUstatParser `AC.manyTill` intrFound