git-annex/Messages/JSON.hs
2016-08-08 10:49:49 -04:00

102 lines
2.6 KiB
Haskell

{- git-annex command-line JSON output and input
-
- Copyright 2011-2016 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE OverloadedStrings #-}
module Messages.JSON (
start,
end,
note,
add,
complete,
DualDisp(..),
ObjectMap(..),
JSONActionItem(..),
) where
import Data.Aeson
import Control.Applicative
import qualified Data.Map as M
import qualified Data.Text as T
import qualified Data.ByteString.Lazy as B
import System.IO
import Data.Monoid
import Prelude
import qualified Utility.JSONStream as Stream
import Types.Key
start :: String -> Maybe FilePath -> Maybe Key -> IO ()
start command file key = B.hPut stdout $ Stream.start $ Stream.AesonObject o
where
Object o = toJSON $ JSONActionItem
{ itemCommand = Just command
, itemKey = key
, itemFile = file
, itemAdded = Nothing
}
end :: Bool -> IO ()
end b = B.hPut stdout $ Stream.add (Stream.JSONChunk [("success", b)]) `B.append` Stream.end
note :: String -> IO ()
note s = add (Stream.JSONChunk [("note", s)])
add :: Stream.JSONChunk a -> IO ()
add = B.hPut stdout . Stream.add
complete :: Stream.JSONChunk a -> IO ()
complete v = B.hPut stdout $ Stream.start v `B.append` Stream.end
-- A value that can be displayed either normally, or as JSON.
data DualDisp = DualDisp
{ dispNormal :: String
, dispJson :: String
}
instance ToJSON DualDisp where
toJSON = toJSON . dispJson
instance Show DualDisp where
show = dispNormal
-- A Map that is serialized to JSON as an object, with each key being a
-- field of the object. This is different from Aeson's normal
-- serialization of Map, which uses "[key, value]".
data ObjectMap a = ObjectMap { fromObjectMap :: M.Map String a }
instance ToJSON a => ToJSON (ObjectMap a) where
toJSON (ObjectMap m) = object $ map go $ M.toList m
where
go (k, v) = (T.pack k, toJSON v)
-- An item that a git-annex command acts on, and displays a JSON object about.
data JSONActionItem a = JSONActionItem
{ itemCommand :: Maybe String
, itemKey :: Maybe Key
, itemFile :: Maybe FilePath
, itemAdded :: Maybe a -- for additional fields added by `add`
}
deriving (Show)
instance ToJSON (JSONActionItem a) where
toJSON i = object
[ "command" .= itemCommand i
, "key" .= (toJSON (itemKey i))
, "file" .= itemFile i
-- itemAdded is not included; must be added later by 'add'
]
instance FromJSON a => FromJSON (JSONActionItem a) where
parseJSON (Object v) = JSONActionItem
<$> (v .:? "command")
<*> (maybe (return Nothing) parseJSON =<< (v .:? "key"))
<*> (v .:? "file")
<*> parseadded
where
parseadded = (Just <$> parseJSON (Object v)) <|> return Nothing
parseJSON _ = mempty