Synnefo » snf-ganeti » ganeti-local

{-| Implementation of the Ganeti Query2 language.

import Text.JSON.Pretty (pp_value)

import Text.JSON.Types

import Text.JSON

import qualified Text.Regex.PCRE as PCRE

import qualified Ganeti.Constants as C

import Ganeti.THH

-- * Sub data types for query2 queries and responses.

-- | List of requested fields.

type Fields = [ String ]

              -> [JSValue]              -- ^ Single argument

              -> Result (Filter a)

readFilterArg constr [flt] = constr <$> readJSON flt

-- | Helper to deserialise an array corresponding to a single field

-- and return the built filter.

                -> [JSValue]         -- ^ Single argument

                -> Result (Filter a)

readFilterField constr [field] = constr <$> readJSON field

-- | Helper to deserialise an array corresponding to a field and

-- value, returning the built filter.

readFilterFieldValue constr [field, value] =

  constr <$> readJSON field <*> readJSON value

readFilterFieldValue _ v =

-- | Inner deserialiser for 'Filter'.

readFilterArray :: (JSON a) => String -> [JSValue] -> Result (Filter a)

readFilterValue (JSString a) = Ok . QuotedString $ fromJSString a

readFilterValue (JSRational _ x) =

  if denominator x /= 1

    else Ok . NumericValue $ numerator x

instance JSON FilterValue where

  showJSON = showFilterValue

-- we don't re-compile the regex at each match attempt.

data FilterRegex = FilterRegex

  { stringRegex   :: String      -- ^ The string version of the regex

  }

-- | Builder for 'FilterRegex'. We always attempt to compile the

-- regular expression on the initialisation of the data structure;

-- this might fail, if the RE is not well-formed.

mkRegex :: (Monad m) => String -> m FilterRegex

mkRegex str = do

  compiled <- case PCRE.getVersion of

                _ -> PCRE.makeRegexM str

  return $ FilterRegex str compiled

-- | 'Show' instance: we show the constructor plus the string version

-- of the regex.