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{-| Implementation of the Ganeti Query2 basic types.

These are types internal to the library, and for example clients that

use the library should not need to import it.

 -}

{-

Copyright (C) 2012 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.Query.Types

  ( FieldGetter(..)

  , FieldData

  , FieldList

  , FieldMap

  , isRuntimeField

  ) where

import qualified Data.Map as Map

import Ganeti.Query.Language

import Ganeti.Objects

-- | The type of field getters. The \"a\" type represents the type

-- we're querying, whereas the \"b\" type represents the \'runtime\'

-- data for that type (if any). Note that we don't support multiple

-- runtime sources, and we always consider the entire configuration as

-- a given (so no equivalent for Python's /*_CONFIG/ and /*_GROUP/;

-- configuration accesses are cheap for us).

data FieldGetter a b = FieldSimple  (a -> ResultEntry)

                     | FieldRuntime (b -> a -> ResultEntry)

                     | FieldConfig  (ConfigData -> a -> ResultEntry)

                     | FieldUnknown

-- | Alias for a field data (definition and getter).

type FieldData a b = (FieldDefinition, FieldGetter a b)

-- | Alias for a field data list.

type FieldList a b = [FieldData a b]

-- | Alias for field maps.

type FieldMap a b = Map.Map String (FieldData a b)

-- | Helper function to check if a getter is a runtime one.

isRuntimeField :: FieldGetter a b -> Bool

isRuntimeField (FieldRuntime _) = True

isRuntimeField _                = False