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{-| Function related to serialisation of WConfD requests

-}

{-

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.WConfd.Language

  ( LockRequestType(..)

  , GanetiLockRequest

  , fromGanetiLockRequest

  ) where

import qualified Text.JSON as J

import Ganeti.Locking.Allocation

import Ganeti.Locking.Locks (GanetiLocks)

-- * Serialisation related to locking

-- | Operation to be carried out on a lock (request exclusive/shared ownership,

-- or release).

data LockRequestType = ReqExclusive | ReqShared | ReqRelease deriving (Eq, Show)

instance J.JSON LockRequestType where

  showJSON ReqExclusive = J.showJSON "exclusive"

  showJSON ReqShared = J.showJSON "shared"

  showJSON ReqRelease = J.showJSON "release"

  readJSON (J.JSString x) = let s = J.fromJSString x

                            in case s of

                              "exclusive" -> J.Ok ReqExclusive

                              "shared" -> J.Ok ReqShared

                              "release" -> J.Ok ReqRelease

                              _ -> J.Error $ "Unknown lock update request " ++ s

  readJSON _ = J.Error "Update requests need to be strings"

-- | The type describing how lock update requests are passed over the wire.

type GanetiLockRequest = [(GanetiLocks, LockRequestType)]

-- | Transform a Lock LockReqeustType pair into a LockRequest.

toLockRequest :: (GanetiLocks, LockRequestType) -> LockRequest GanetiLocks

toLockRequest (a, ReqExclusive) = requestExclusive a

toLockRequest (a, ReqShared) = requestShared a

toLockRequest (a, ReqRelease) = requestRelease a

-- | From a GanetiLockRequest obtain a list of

-- Ganeti.Lock.Allocation.LockRequest, suitable to updateLocks.

fromGanetiLockRequest :: GanetiLockRequest -> [LockRequest GanetiLocks]

fromGanetiLockRequest = map toLockRequest