e213ef310f
* Fix minor FD leak in journal code. Closes: #754608 * direct: Fix handling of case where a work tree subdirectory cannot be written to due to permissions. * migrate: Avoid re-checksumming when migrating from hashE to hash backend. * uninit: Avoid failing final removal in some direct mode repositories due to file modes. * S3: Deal with AWS ACL configurations that do not allow creating or checking the location of a bucket, but only reading and writing content to it. * resolvemerge: New plumbing command that runs the automatic merge conflict resolver. * Deal with change in git 2.0 that made indirect mode merge conflict resolution leave behind old files. * sync: Fix git sync with local git remotes even when they don't have an annex.uuid set. (The assistant already did so.) * Set gcrypt-publish-participants when setting up a gcrypt repository, to avoid unncessary passphrase prompts. This is a security/usability tradeoff. To avoid exposing the gpg key ids who can decrypt the repository, users can unset gcrypt-publish-participants. * Install nautilus hooks even when ~/.local/share/nautilus/ does not yet exist, since it is not automatically created for Gnome 3 users. * Windows: Move .vbs files out of git\bin, to avoid that being in the PATH, which caused some weird breakage. (Thanks, divB) * Windows: Fix locking issue that prevented the webapp starting (since 5.20140707). # imported from the archive
90 lines
2.3 KiB
Haskell
90 lines
2.3 KiB
Haskell
{- Simple line-based protocols.
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-
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- Copyright 2013-2014 Joey Hess <joey@kitenet.net>
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-
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- License: BSD-2-clause
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-}
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module Utility.SimpleProtocol (
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Sendable(..),
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Receivable(..),
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parseMessage,
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Serializable(..),
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Parser,
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parseFail,
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parse0,
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parse1,
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parse2,
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parse3,
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ioHandles,
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) where
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import Data.Char
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import GHC.IO.Handle
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import Common
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-- Messages that can be sent.
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class Sendable m where
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formatMessage :: m -> [String]
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-- Messages that can be received.
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class Receivable m where
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-- Passed the first word of the message, returns
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-- a Parser that can be be fed the rest of the message to generate
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-- the value.
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parseCommand :: String -> Parser m
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parseMessage :: (Receivable m) => String -> Maybe m
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parseMessage s = parseCommand command rest
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where
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(command, rest) = splitWord s
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class Serializable a where
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serialize :: a -> String
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deserialize :: String -> Maybe a
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{- Parsing the parameters of messages. Using the right parseN ensures
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- that the string is split into exactly the requested number of words,
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- which allows the last parameter of a message to contain arbitrary
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- whitespace, etc, without needing any special quoting.
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-}
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type Parser a = String -> Maybe a
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parseFail :: Parser a
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parseFail _ = Nothing
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parse0 :: a -> Parser a
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parse0 mk "" = Just mk
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parse0 _ _ = Nothing
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parse1 :: Serializable p1 => (p1 -> a) -> Parser a
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parse1 mk p1 = mk <$> deserialize p1
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parse2 :: (Serializable p1, Serializable p2) => (p1 -> p2 -> a) -> Parser a
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parse2 mk s = mk <$> deserialize p1 <*> deserialize p2
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where
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(p1, p2) = splitWord s
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parse3 :: (Serializable p1, Serializable p2, Serializable p3) => (p1 -> p2 -> p3 -> a) -> Parser a
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parse3 mk s = mk <$> deserialize p1 <*> deserialize p2 <*> deserialize p3
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where
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(p1, rest) = splitWord s
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(p2, p3) = splitWord rest
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splitWord :: String -> (String, String)
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splitWord = separate isSpace
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{- When a program speaks a simple protocol over stdio, any other output
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- to stdout (or anything that attempts to read from stdin)
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- will mess up the protocol. To avoid that, close stdin, and
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- and duplicate stderr to stdout. Return two new handles
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- that are duplicates of the original (stdin, stdout). -}
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ioHandles :: IO (Handle, Handle)
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ioHandles = do
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readh <- hDuplicate stdin
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writeh <- hDuplicate stdout
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nullh <- openFile devNull ReadMode
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nullh `hDuplicateTo` stdin
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stderr `hDuplicateTo` stdout
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return (readh, writeh)
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