
I tend to prefer moving toward explicit exception handling, not away from it, but in this case, I think there are good reasons to let checkPresent throw exceptions: 1. They can all be caught in one place (Remote.hasKey), and we know every possible exception is caught there now, which we didn't before. 2. It simplified the code of the Remotes. I think it makes sense for Remotes to be able to be implemented without needing to worry about catching exceptions inside them. (Mostly.) 3. Types.StoreRetrieve.Preparer can only work on things that return a Bool, which all the other relevant remote methods already did. I do not see a good way to generalize that type; my previous attempts failed miserably.
109 lines
3.5 KiB
Haskell
109 lines
3.5 KiB
Haskell
{- git-annex remotes types
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-
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- Most things should not need this, using Types instead
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-
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- Copyright 2011-2014 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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module Types.Remote
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( RemoteConfigKey
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, RemoteConfig
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, RemoteTypeA(..)
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, RemoteA(..)
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, Availability(..)
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)
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where
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import Data.Map as M
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import Data.Ord
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import qualified Git
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import Types.Key
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import Types.UUID
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import Types.GitConfig
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import Types.Availability
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import Types.Creds
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import Config.Cost
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import Utility.Metered
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import Git.Types
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import Utility.SafeCommand
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type RemoteConfigKey = String
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type RemoteConfig = M.Map RemoteConfigKey String
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{- There are different types of remotes. -}
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data RemoteTypeA a = RemoteType {
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-- human visible type name
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typename :: String,
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-- enumerates remotes of this type
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enumerate :: a [Git.Repo],
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-- generates a remote of this type
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generate :: Git.Repo -> UUID -> RemoteConfig -> RemoteGitConfig -> a (Maybe (RemoteA a)),
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-- initializes or changes a remote
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setup :: Maybe UUID -> Maybe CredPair -> RemoteConfig -> a (RemoteConfig, UUID)
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}
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instance Eq (RemoteTypeA a) where
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x == y = typename x == typename y
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{- An individual remote. -}
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data RemoteA a = Remote {
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-- each Remote has a unique uuid
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uuid :: UUID,
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-- each Remote has a human visible name
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name :: RemoteName,
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-- Remotes have a use cost; higher is more expensive
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cost :: Cost,
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-- Transfers a key's contents from disk to the remote.
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-- The key should not appear to be present on the remote until
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-- all of its contents have been transferred.
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storeKey :: Key -> AssociatedFile -> MeterUpdate -> a Bool,
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-- Retrieves a key's contents to a file.
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-- (The MeterUpdate does not need to be used if it retrieves
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-- directly to the file, and not to an intermediate file.)
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retrieveKeyFile :: Key -> AssociatedFile -> FilePath -> MeterUpdate -> a Bool,
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-- retrieves a key's contents to a tmp file, if it can be done cheaply
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retrieveKeyFileCheap :: Key -> FilePath -> a Bool,
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-- removes a key's contents (succeeds if the contents are not present)
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removeKey :: Key -> a Bool,
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-- Checks if a key is present in the remote.
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-- Throws an exception if the remote cannot be accessed.
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checkPresent :: Key -> a Bool,
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-- Some remotes can checkPresent without an expensive network
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-- operation.
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checkPresentCheap :: Bool,
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-- Some remotes can provide additional details for whereis.
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whereisKey :: Maybe (Key -> a [String]),
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-- Some remotes can run a fsck operation on the remote,
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-- without transferring all the data to the local repo
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-- The parameters are passed to the fsck command on the remote.
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remoteFsck :: Maybe ([CommandParam] -> a (IO Bool)),
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-- Runs an action to repair the remote's git repository.
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repairRepo :: Maybe (a Bool -> a (IO Bool)),
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-- a Remote has a persistent configuration store
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config :: RemoteConfig,
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-- git repo for the Remote
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repo :: Git.Repo,
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-- a Remote's configuration from git
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gitconfig :: RemoteGitConfig,
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-- a Remote can be assocated with a specific local filesystem path
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localpath :: Maybe FilePath,
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-- a Remote can be known to be readonly
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readonly :: Bool,
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-- a Remote can be globally available. (Ie, "in the cloud".)
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availability :: Availability,
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-- the type of the remote
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remotetype :: RemoteTypeA a
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}
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instance Show (RemoteA a) where
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show remote = "Remote { name =\"" ++ name remote ++ "\" }"
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-- two remotes are the same if they have the same uuid
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instance Eq (RemoteA a) where
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x == y = uuid x == uuid y
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instance Ord (RemoteA a) where
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compare = comparing uuid
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