git-annex/Annex.hs
Joey Hess 0a36f92a31 more command-specific options
Made --from and --to command-specific options.

Added generic storage for values of command-specific options,
which allows removing some of the special case fields in AnnexState.

(Also added generic storage for command-specific flags, although there are
not yet any.)

Note that this storage uses a Map, so repeatedly looking up the same value
is slightly more expensive than looking up an AnnexState field. But, the
value can be looked up once in the seek stage, transformed as necessary,
and passed in a closure to the start stage, and this avoids that overhead.

Still, I'm hesitant to use this for things like force or fast flags.
It's probably best to reserve it for flags that are only used by a few
commands, or options like --from and --to that it's important only be
allowed to be used with commands that implement them, to avoid user
confusion.
2012-01-06 03:16:42 -04:00

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{- git-annex monad
-
- Copyright 2010-2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE GeneralizedNewtypeDeriving, TypeFamilies, MultiParamTypeClasses #-}
module Annex (
Annex,
AnnexState(..),
OutputType(..),
new,
newState,
run,
eval,
getState,
changeState,
setFlag,
setField,
getFlag,
getField,
gitRepo,
inRepo,
fromRepo,
) where
import Control.Monad.State
import Control.Monad.Trans.Control (StM, MonadBaseControl, liftBaseWith, restoreM)
import Control.Monad.Base (liftBase, MonadBase)
import Common
import qualified Git
import qualified Git.Config
import Git.CatFile
import qualified Git.Queue
import Types.Backend
import qualified Types.Remote
import Types.Crypto
import Types.BranchState
import Types.TrustLevel
import Types.UUID
import qualified Utility.Matcher
import qualified Data.Map as M
-- git-annex's monad
newtype Annex a = Annex { runAnnex :: StateT AnnexState IO a }
deriving (
Monad,
MonadIO,
MonadState AnnexState,
Functor,
Applicative
)
instance MonadBase IO Annex where
liftBase = Annex . liftBase
instance MonadBaseControl IO Annex where
newtype StM Annex a = StAnnex (StM (StateT AnnexState IO) a)
liftBaseWith f = Annex $ liftBaseWith $ \runInIO ->
f $ liftM StAnnex . runInIO . runAnnex
restoreM = Annex . restoreM . unStAnnex
where
unStAnnex (StAnnex st) = st
data OutputType = NormalOutput | QuietOutput | JSONOutput
type Matcher a = Either [Utility.Matcher.Token a] (Utility.Matcher.Matcher a)
-- internal state storage
data AnnexState = AnnexState
{ repo :: Git.Repo
, backends :: [BackendA Annex]
, remotes :: [Types.Remote.RemoteA Annex]
, repoqueue :: Git.Queue.Queue
, output :: OutputType
, force :: Bool
, fast :: Bool
, auto :: Bool
, branchstate :: BranchState
, catfilehandle :: Maybe CatFileHandle
, forcebackend :: Maybe String
, forcenumcopies :: Maybe Int
, limit :: Matcher (FilePath -> Annex Bool)
, forcetrust :: [(UUID, TrustLevel)]
, trustmap :: Maybe TrustMap
, ciphers :: M.Map EncryptedCipher Cipher
, flags :: M.Map String Bool
, fields :: M.Map String String
}
newState :: Git.Repo -> AnnexState
newState gitrepo = AnnexState
{ repo = gitrepo
, backends = []
, remotes = []
, repoqueue = Git.Queue.new
, output = NormalOutput
, force = False
, fast = False
, auto = False
, branchstate = startBranchState
, catfilehandle = Nothing
, forcebackend = Nothing
, forcenumcopies = Nothing
, limit = Left []
, forcetrust = []
, trustmap = Nothing
, ciphers = M.empty
, flags = M.empty
, fields = M.empty
}
{- Create and returns an Annex state object for the specified git repo. -}
new :: Git.Repo -> IO AnnexState
new gitrepo = newState <$> Git.Config.read gitrepo
{- performs an action in the Annex monad -}
run :: AnnexState -> Annex a -> IO (a, AnnexState)
run s a = runStateT (runAnnex a) s
eval :: AnnexState -> Annex a -> IO a
eval s a = evalStateT (runAnnex a) s
{- Gets a value from the internal state, selected by the passed value
- constructor. -}
getState :: (AnnexState -> a) -> Annex a
getState = gets
{- Applies a state mutation function to change the internal state.
-
- Example: changeState $ \s -> s { output = QuietOutput }
-}
changeState :: (AnnexState -> AnnexState) -> Annex ()
changeState = modify
{- Sets a flag to True -}
setFlag :: String -> Annex ()
setFlag flag = changeState $ \s ->
s { flags = M.insert flag True $ flags s }
{- Sets a field to a value -}
setField :: String -> String -> Annex ()
setField field value = changeState $ \s ->
s { fields = M.insert field value $ fields s }
{- Checks if a flag was set. -}
getFlag :: String -> Annex Bool
getFlag flag = fromMaybe False . M.lookup flag <$> getState flags
{- Gets the value of a field. -}
getField :: String -> Annex (Maybe String)
getField field = M.lookup field <$> getState fields
{- Returns the annex's git repository. -}
gitRepo :: Annex Git.Repo
gitRepo = getState repo
{- Runs an IO action in the annex's git repository. -}
inRepo :: (Git.Repo -> IO a) -> Annex a
inRepo a = liftIO . a =<< gitRepo
{- Extracts a value from the annex's git repisitory. -}
fromRepo :: (Git.Repo -> a) -> Annex a
fromRepo a = a <$> gitRepo