git-annex/Utility/Rsync.hs
2014-12-17 13:21:55 -04:00

129 lines
4.2 KiB
Haskell

{- various rsync stuff
-
- Copyright 2010-2013 Joey Hess <joey@kitenet.net>
-
- License: BSD-2-clause
-}
module Utility.Rsync where
import Common
import Utility.Metered
import Data.Char
import System.Console.GetOpt
import Data.Tuple.Utils
{- Generates parameters to make rsync use a specified command as its remote
- shell. -}
rsyncShell :: [CommandParam] -> [CommandParam]
rsyncShell command = [Param "-e", Param $ unwords $ map escape (toCommand command)]
where
{- rsync requires some weird, non-shell like quoting in
- here. A doubled single quote inside the single quoted
- string is a single quote. -}
escape s = "'" ++ intercalate "''" (split "'" s) ++ "'"
{- Runs rsync in server mode to send a file. -}
rsyncServerSend :: [CommandParam] -> FilePath -> IO Bool
rsyncServerSend options file = rsync $
rsyncServerParams ++ Param "--sender" : options ++ [File file]
{- Runs rsync in server mode to receive a file. -}
rsyncServerReceive :: [CommandParam] -> FilePath -> IO Bool
rsyncServerReceive options file = rsync $
rsyncServerParams ++ options ++ [File file]
rsyncServerParams :: [CommandParam]
rsyncServerParams =
[ Param "--server"
-- preserve timestamps
, Param "-t"
-- allow resuming of transfers of big files
, Param "--inplace"
-- other options rsync normally uses in server mode
, Params "-e.Lsf ."
]
rsyncUseDestinationPermissions :: CommandParam
rsyncUseDestinationPermissions = Param "--chmod=ugo=rwX"
rsync :: [CommandParam] -> IO Bool
rsync = boolSystem "rsync" . rsyncParamsFixup
{- On Windows, rsync is from Cygwin, and expects to get Cygwin formatted
- paths to files. (It thinks that C:foo refers to a host named "C").
- Fix up all Files in the Params appropriately. -}
rsyncParamsFixup :: [CommandParam] -> [CommandParam]
rsyncParamsFixup = map fixup
where
fixup (File f) = File (toCygPath f)
fixup p = p
{- Checks if an rsync url involves the remote shell (ssh or rsh).
- Use of such urls with rsync requires additional shell
- escaping. -}
rsyncUrlIsShell :: String -> Bool
rsyncUrlIsShell s
| "rsync://" `isPrefixOf` s = False
| otherwise = go s
where
-- host::dir is rsync protocol, while host:dir is ssh/rsh
go [] = False
go (c:cs)
| c == '/' = False -- got to directory with no colon
| c == ':' = not $ ":" `isPrefixOf` cs
| otherwise = go cs
{- Checks if a rsync url is really just a local path. -}
rsyncUrlIsPath :: String -> Bool
rsyncUrlIsPath s
| rsyncUrlIsShell s = False
| otherwise = ':' `notElem` s
{- Runs rsync, but intercepts its progress output and updates a meter.
- The progress output is also output to stdout.
-
- The params must enable rsync's --progress mode for this to work.
-}
rsyncProgress :: MeterUpdate -> [CommandParam] -> IO Bool
rsyncProgress meterupdate = commandMeter parseRsyncProgress meterupdate "rsync"
{- Strategy: Look for chunks prefixed with \r (rsync writes a \r before
- the first progress output, and each thereafter). The first number
- after the \r is the number of bytes processed. After the number,
- there must appear some whitespace, or we didn't get the whole number,
- and return the \r and part we did get, for later processing.
-
- In some locales, the number will have one or more commas in the middle
- of it.
-}
parseRsyncProgress :: ProgressParser
parseRsyncProgress = go [] . reverse . progresschunks
where
go remainder [] = (Nothing, remainder)
go remainder (x:xs) = case parsebytes (findbytesstart x) of
Nothing -> go (delim:x++remainder) xs
Just b -> (Just (toBytesProcessed b), remainder)
delim = '\r'
{- Find chunks that each start with delim.
- The first chunk doesn't start with it
- (it's empty when delim is at the start of the string). -}
progresschunks = drop 1 . split [delim]
findbytesstart s = dropWhile isSpace s
parsebytes :: String -> Maybe Integer
parsebytes s = case break isSpace s of
([], _) -> Nothing
(_, []) -> Nothing
(b, _) -> readish $ filter (/= ',') b
{- Filters options to those that are safe to pass to rsync in server mode,
- without causing it to eg, expose files. -}
filterRsyncSafeOptions :: [String] -> [String]
filterRsyncSafeOptions = fst3 . getOpt Permute
[ Option [] ["bwlimit"] (reqArgLong "bwlimit") "" ]
where
reqArgLong x = ReqArg (\v -> "--" ++ x ++ "=" ++ v) ""