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|
{- various rsync stuff
-
- Copyright 2010-2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Utility.Rsync where
import Common
import Utility.Metered
import Data.Char
{- 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 = "'" ++ join "''" (split "'" s) ++ "'"
{- Runs rsync in server mode to send a file. -}
rsyncServerSend :: FilePath -> IO Bool
rsyncServerSend file = rsync $
rsyncServerParams ++ [Param "--sender", File file]
{- Runs rsync in server mode to receive a file. -}
rsyncServerReceive :: FilePath -> IO Bool
rsyncServerReceive file = rsync $ rsyncServerParams ++ [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 ."
]
rsync :: [CommandParam] -> IO Bool
rsync = boolSystem "rsync"
{- 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 params = do
r <- withHandle StdoutHandle createProcessSuccess p (feedprogress 0 [])
{- For an unknown reason, piping rsync's output like this does
- causes it to run a second ssh process, which it neglects to wait
- on. Reap the resulting zombie. -}
reapZombies
return r
where
p = proc "rsync" (toCommand params)
feedprogress prev buf h = do
s <- hGetSomeString h 80
if null s
then return True
else do
putStr s
hFlush stdout
let (mbytes, buf') = parseRsyncProgress (buf++s)
case mbytes of
Nothing -> feedprogress prev buf' h
(Just bytes) -> do
when (bytes /= prev) $
meterupdate $ toBytesProcessed bytes
feedprogress bytes buf' h
{- 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
{- Parses the String looking for rsync progress output, and returns
- Maybe the number of bytes rsynced so far, and any any remainder of the
- string that could be an incomplete progress output. That remainder
- should be prepended to future output, and fed back in. This interface
- allows the output to be read in any desired size chunk, or even one
- character at a time.
-
- 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.
-}
parseRsyncProgress :: String -> (Maybe Integer, String)
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 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 s = case break isSpace s of
([], _) -> Nothing
(_, []) -> Nothing
(b, _) -> readish b
|
