thread State thru to backends

This commit is contained in:
Joey Hess 2010-10-12 16:06:10 -04:00
parent 759f146d0f
commit 2ac47a3a59
8 changed files with 67 additions and 77 deletions

View file

@ -45,12 +45,12 @@ startAnnex = do
- the annex directory and setting up the symlink pointing to its content. -}
annexFile :: State -> FilePath -> IO ()
annexFile state file = do
alreadyannexed <- lookupBackend (backends state) (repo state) file
alreadyannexed <- lookupBackend (backends state) state file
case (alreadyannexed) of
Just _ -> error $ "already annexed: " ++ file
Nothing -> do
checkLegal file
stored <- storeFile (backends state) (repo state) file
stored <- storeFile (backends state) state file
case (stored) of
Nothing -> error $ "no backend could store: " ++ file
Just key -> symlink key
@ -70,11 +70,11 @@ annexFile state file = do
{- Inverse of annexFile. -}
unannexFile :: State -> FilePath -> IO ()
unannexFile state file = do
alreadyannexed <- lookupBackend (backends state) (repo state) file
alreadyannexed <- lookupBackend (backends state) state file
case (alreadyannexed) of
Nothing -> error $ "not annexed " ++ file
Just _ -> do
mkey <- dropFile (backends state) (repo state) file
mkey <- dropFile (backends state) state file
case (mkey) of
Nothing -> return ()
Just key -> do
@ -86,7 +86,7 @@ unannexFile state file = do
{- Transfers the file from a remote. -}
annexGetFile :: State -> FilePath -> IO ()
annexGetFile state file = do
alreadyannexed <- lookupBackend (backends state) (repo state) file
alreadyannexed <- lookupBackend (backends state) state file
case (alreadyannexed) of
Nothing -> error $ "not annexed " ++ file
Just _ -> do error "not implemented" -- TODO

View file

@ -28,74 +28,75 @@ import System.Directory
import Locations
import GitRepo
import Utility
import BackendType
import Types
{- Name of state file that holds the key for an annexed file,
- using a given backend. -}
backendFile :: Backend -> GitRepo -> FilePath -> String
backendFile backend repo file = gitStateDir repo ++
(gitRelative repo file) ++ "." ++ (name backend)
backendFile :: Backend -> State -> FilePath -> String
backendFile backend state file =
gitStateDir (repo state) ++ (gitRelative (repo state) file) ++
"." ++ (name backend)
{- Attempts to store a file in one of the backends, and returns
- its key. -}
storeFile :: [Backend] -> GitRepo -> FilePath -> IO (Maybe Key)
storeFile :: [Backend] -> State -> FilePath -> IO (Maybe Key)
storeFile [] _ _ = return Nothing
storeFile (b:bs) repo file = do
try <- (getKey b) repo (gitRelative repo file)
storeFile (b:bs) state file = do
try <- (getKey b) state (gitRelative (repo state) file)
case (try) of
Nothing -> nextbackend
Just key -> do
stored <- (storeFileKey b) repo file key
stored <- (storeFileKey b) state file key
if (not stored)
then nextbackend
else do
bookkeeping key
return $ Just key
where
nextbackend = storeFile bs repo file
backendfile = backendFile b repo file
nextbackend = storeFile bs state file
backendfile = backendFile b state file
bookkeeping key = do
createDirectoryIfMissing True (parentDir backendfile)
writeFile backendfile key
{- Attempts to retrieve an file from one of the backends, saving it to
- a specified location. -}
retrieveFile :: [Backend] -> GitRepo -> FilePath -> FilePath -> IO Bool
retrieveFile backends repo file dest = do
result <- lookupBackend backends repo file
retrieveFile :: [Backend] -> State -> FilePath -> FilePath -> IO Bool
retrieveFile backends state file dest = do
result <- lookupBackend backends state file
case (result) of
Nothing -> return False
Just b -> do
key <- lookupKey b repo file
key <- lookupKey b state file
(retrieveKeyFile b) key dest
{- Drops the key for a file from the backend that has it. -}
dropFile :: [Backend] -> GitRepo -> FilePath -> IO (Maybe Key)
dropFile backends repo file = do
result <- lookupBackend backends repo file
dropFile :: [Backend] -> State -> FilePath -> IO (Maybe Key)
dropFile backends state file = do
result <- lookupBackend backends state file
case (result) of
Nothing -> return Nothing
Just b -> do
key <- lookupKey b repo file
key <- lookupKey b state file
(removeKey b) key
removeFile $ backendFile b repo file
removeFile $ backendFile b state file
return $ Just key
{- Looks up the key a backend uses for an already annexed file. -}
lookupKey :: Backend -> GitRepo -> FilePath -> IO Key
lookupKey backend repo file = readFile (backendFile backend repo file)
lookupKey :: Backend -> State -> FilePath -> IO Key
lookupKey backend state file = readFile (backendFile backend state file)
{- Looks up the backend used for an already annexed file. -}
lookupBackend :: [Backend] -> GitRepo -> FilePath -> IO (Maybe Backend)
lookupBackend :: [Backend] -> State -> FilePath -> IO (Maybe Backend)
lookupBackend [] _ _ = return Nothing
lookupBackend (b:bs) repo file = do
present <- checkBackend b repo file
lookupBackend (b:bs) state file = do
present <- checkBackend b state file
if present
then
return $ Just b
else
lookupBackend bs repo file
lookupBackend bs state file
{- Checks if a file is available via a given backend. -}
checkBackend :: Backend -> GitRepo -> FilePath -> IO (Bool)
checkBackend backend repo file = doesFileExist $ backendFile backend repo file
checkBackend :: Backend -> State -> FilePath -> IO (Bool)
checkBackend backend state file = doesFileExist $ backendFile backend state file

View file

@ -5,7 +5,7 @@ module BackendChecksum (backend) where
import qualified BackendFile
import Data.Digest.Pure.SHA
import BackendType
import Types
import GitRepo
-- based on BackendFile just with a different key type
@ -15,5 +15,5 @@ backend = BackendFile.backend {
}
-- checksum the file to get its key
keyValue :: GitRepo -> FilePath -> IO (Maybe Key)
keyValue :: State -> FilePath -> IO (Maybe Key)
keyValue k = error "checksum keyValue unimplemented" -- TODO

View file

@ -3,7 +3,7 @@
module BackendFile (backend) where
import BackendType
import Types
import GitRepo
backend = Backend {
@ -15,15 +15,15 @@ backend = Backend {
}
-- direct mapping from filename to key
keyValue :: GitRepo -> FilePath -> IO (Maybe Key)
keyValue repo file = return $ Just file
keyValue :: State -> FilePath -> IO (Maybe Key)
keyValue state file = return $ Just file
{- This backend does not really do any independant data storage,
- it relies on the file contents in .git/annex/ in this repo,
- and other accessible repos. So storing or removing a key is
- a no-op. -}
dummyStore :: GitRepo -> FilePath -> Key -> IO (Bool)
dummyStore repo file key = return True
dummyStore :: State -> FilePath -> Key -> IO (Bool)
dummyStore state file key = return True
dummyRemove :: Key -> IO Bool
dummyRemove url = return False

View file

@ -7,7 +7,7 @@ module BackendList (
lookupBackendName
) where
import BackendType
import Types
-- When adding a new backend, import it here and add it to the list.
import qualified BackendFile

View file

@ -1,31 +0,0 @@
{- git-annex backend data types
- -}
module BackendType (
-- the entire types are exported, for use in backend implementations
Key(..),
Backend(..)
) where
import GitRepo
-- annexed filenames are mapped into keys
type Key = FilePath
-- this structure represents a key/value backend
data Backend = Backend {
-- name of this backend
name :: String,
-- converts a filename to a key
getKey :: GitRepo -> FilePath -> IO (Maybe Key),
-- stores a file's contents to a key
storeFileKey :: GitRepo -> FilePath -> Key -> IO Bool,
-- retrieves a key's contents to a file
retrieveKeyFile :: Key -> FilePath -> IO Bool,
-- removes a key
removeKey :: Key -> IO Bool
}
instance Show Backend where
show backend = "Backend { name =\"" ++ (name backend) ++ "\" }"

View file

@ -3,8 +3,7 @@
module BackendUrl (backend) where
import BackendType
import GitRepo
import Types
backend = Backend {
name = "url",
@ -15,11 +14,11 @@ backend = Backend {
}
-- cannot generate url from filename
keyValue :: GitRepo -> FilePath -> IO (Maybe Key)
keyValue :: State -> FilePath -> IO (Maybe Key)
keyValue repo file = return Nothing
-- cannot change urls
dummyStore :: GitRepo -> FilePath -> Key -> IO Bool
dummyStore :: State -> FilePath -> Key -> IO Bool
dummyStore repo file url = return False
dummyRemove :: Key -> IO Bool
dummyRemove url = return False

View file

@ -1,14 +1,35 @@
{- git-annex core data types -}
module Types (
State(..)
State(..),
Key(..),
Backend(..)
) where
import BackendType
import GitRepo
-- git-annex's runtime state
data State = State {
repo :: GitRepo,
backends :: [Backend]
} deriving (Show)
-- annexed filenames are mapped into keys
type Key = FilePath
-- this structure represents a key/value backend
data Backend = Backend {
-- name of this backend
name :: String,
-- converts a filename to a key
getKey :: State -> FilePath -> IO (Maybe Key),
-- stores a file's contents to a key
storeFileKey :: State -> FilePath -> Key -> IO Bool,
-- retrieves a key's contents to a file
retrieveKeyFile :: Key -> FilePath -> IO Bool,
-- removes a key
removeKey :: Key -> IO Bool
}
instance Show Backend where
show backend = "Backend { name =\"" ++ (name backend) ++ "\" }"