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{-| Implementation of the Ganeti Query2 common objects.

 -}

{-

Copyright (C) 2012, 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.Query.Common

  ( NoDataRuntime(..)

  , rsNoData

  , rsUnavail

  , rsNormal

  , rsMaybeNoData

  , rsMaybeUnavail

  , rsUnknown

  , missingRuntime

  , rpcErrorToStatus

  , timeStampFields

  , uuidFields

  , serialFields

  , tagsFields

  , dictFieldGetter

  , buildNdParamField

  ) where

import qualified Data.Map as Map

import Data.Maybe (fromMaybe)

import Text.JSON (JSON, showJSON)

import qualified Ganeti.Constants as C

import Ganeti.Config

import Ganeti.Objects

import Ganeti.Rpc

import Ganeti.Query.Language

import Ganeti.Query.Types

import Ganeti.Types

-- | The runtime used by queries which retrieve no live data.

data NoDataRuntime = NoDataRuntime

-- * Generic functions

-- | Conversion from 'VType' to 'FieldType'.

vTypeToQFT :: VType -> FieldType

vTypeToQFT VTypeString      = QFTOther

vTypeToQFT VTypeMaybeString = QFTOther

vTypeToQFT VTypeBool        = QFTBool

vTypeToQFT VTypeSize        = QFTUnit

vTypeToQFT VTypeInt         = QFTNumber

-- * Result helpers

-- | Helper for a result with no data.

rsNoData :: ResultEntry

rsNoData = ResultEntry RSNoData Nothing

-- | Helper for result for an entity which supports no such field.

rsUnavail :: ResultEntry

rsUnavail = ResultEntry RSUnavail Nothing

-- | Helper to declare a normal result.

rsNormal :: (JSON a) => a -> ResultEntry

rsNormal a = ResultEntry RSNormal $ Just (showJSON a)

-- | Helper to declare a result from a 'Maybe' (the item might be

-- missing, in which case we return no data). Note that there's some

-- ambiguity here: in some cases, we mean 'RSNoData', but in other

-- 'RSUnavail'; this is easy to solve in simple cases, but not in

-- nested dicts. If you want to return 'RSUnavail' in case of 'Nothing'

-- use the function 'rsMaybeUnavail'.

rsMaybeNoData :: (JSON a) => Maybe a -> ResultEntry

rsMaybeNoData = maybe rsNoData rsNormal

-- | Helper to declare a result from a 'Maybe'. This version returns

-- a 'RSUnavail' in case of 'Nothing'. It should be used for optional

-- fields that are not set. For cases where 'Nothing' means that there

-- was an error, consider using 'rsMaybe' instead.

rsMaybeUnavail :: (JSON a) => Maybe a -> ResultEntry

rsMaybeUnavail = maybe rsUnavail rsNormal

-- | Helper for unknown field result.

rsUnknown :: ResultEntry

rsUnknown = ResultEntry RSUnknown Nothing

-- | Helper for a missing runtime parameter.

missingRuntime :: FieldGetter a b

missingRuntime = FieldRuntime (\_ _ -> ResultEntry RSNoData Nothing)

-- * Error conversion

-- | Convert RpcError to ResultStatus

rpcErrorToStatus :: RpcError -> ResultStatus

rpcErrorToStatus OfflineNodeError = RSOffline

rpcErrorToStatus _ = RSNoData

-- * Common fields

-- | The list of timestamp fields.

timeStampFields :: (TimeStampObject a) => FieldList a b

timeStampFields =

  [ (FieldDefinition "ctime" "CTime" QFTTimestamp "Creation timestamp",

     FieldSimple (rsNormal . cTimeOf), QffNormal)

  , (FieldDefinition "mtime" "MTime" QFTTimestamp "Modification timestamp",

     FieldSimple (rsNormal . mTimeOf), QffNormal)

  ]

-- | The list of UUID fields.

uuidFields :: (UuidObject a) => String -> FieldList a b

uuidFields name =

  [ (FieldDefinition "uuid" "UUID" QFTText  (name ++ " UUID"),

     FieldSimple (rsNormal . uuidOf), QffNormal) ]

-- | The list of serial number fields.

serialFields :: (SerialNoObject a) => String -> FieldList a b

serialFields name =

  [ (FieldDefinition "serial_no" "SerialNo" QFTNumber

     (name ++ " object serial number, incremented on each modification"),

     FieldSimple (rsNormal . serialOf), QffNormal) ]

-- | The list of tag fields.

tagsFields :: (TagsObject a) => FieldList a b

tagsFields =

  [ (FieldDefinition "tags" "Tags" QFTOther "Tags",

     FieldSimple (rsNormal . tagsOf), QffNormal) ]

-- * Generic parameter functions

-- | Returns a field from a (possibly missing) 'DictObject'. This is

-- used by parameter dictionaries, usually. Note that we have two

-- levels of maybe: the top level dict might be missing, or one key in

-- the dictionary might be.

dictFieldGetter :: (DictObject a) => String -> Maybe a -> ResultEntry

dictFieldGetter k = maybe rsNoData (rsMaybeNoData . lookup k . toDict)

-- | Ndparams optimised lookup map.

ndParamTypes :: Map.Map String FieldType

ndParamTypes = Map.map vTypeToQFT C.ndsParameterTypes

-- | Ndparams title map.

ndParamTitles :: Map.Map String FieldTitle

ndParamTitles = C.ndsParameterTitles

-- | Ndparam getter builder: given a field, it returns a FieldConfig

-- getter, that is a function that takes the config and the object and

-- returns the Ndparam field specified when the getter was built.

ndParamGetter :: (NdParamObject a) =>

                 String -- ^ The field we're building the getter for

              -> ConfigData -> a -> ResultEntry

ndParamGetter field config =

  dictFieldGetter field . getNdParamsOf config

-- | Builds the ndparam fields for an object.

buildNdParamField :: (NdParamObject a) => String -> FieldData a b

buildNdParamField field =

  let full_name = "ndp/" ++ field

      title = fromMaybe field $ field `Map.lookup` ndParamTitles

      qft = fromMaybe QFTOther $ field `Map.lookup` ndParamTypes

      desc = "The \"" ++ field ++ "\" node parameter"

  in (FieldDefinition full_name title qft desc,

      FieldConfig (ndParamGetter field), QffNormal)