Parsers.hs 2.21 KB
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{-# LANGUAGE OverloadedStrings #-}
{-| Utility functions for several parsers

This module holds the definition for some utility functions for two
parsers.  The parser for the @/proc/stat@ file and the parser for the
@/proc/diskstats@ file.

-}
{-

Copyright (C) 2013 Google Inc.
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All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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-}
module Ganeti.Parsers where

import Control.Applicative ((*>))
import qualified Data.Attoparsec.Text as A
import Data.Attoparsec.Text (Parser)
import Data.Text (unpack)

-- * Utility functions

-- | Our own space-skipping function, because A.skipSpace also skips
-- newline characters. It skips ZERO or more spaces, so it does not
-- fail if there are no spaces.
skipSpaces :: Parser ()
skipSpaces = A.skipWhile A.isHorizontalSpace

-- | A parser recognizing a number preceeded by spaces.
numberP :: Parser Int
numberP = skipSpaces *> A.decimal

-- | A parser recognizing a word preceded by spaces, and closed by a space.
stringP :: Parser String
stringP = skipSpaces *> fmap unpack (A.takeWhile $ not . A.isHorizontalSpace)