git-annex/Utility/Misc.hs
Joey Hess 9b1fe37818
improve adjusted branch name parsing to support adjusted view branches
An adjusted view branch has a name like
"adjusted/views/master(author=_)(unlocked)"
and so the adjustment starts at the last open paren, not the first open
paren.

Note that git-annex sync still does not do anything useful when run in
such a branch, because it does not realize that it is a view branch.
This is only groundwork for adjusted view branches.

This also fixes adjusted branches when the basis branch name contains
parens for some other reason, though that is not common in a git branch
name.

Sponsored-by: Boyd Stephen Smith Jr. on Patreon
2023-02-27 14:09:05 -04:00

147 lines
4 KiB
Haskell

{- misc utility functions
-
- Copyright 2010-2011 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
{-# OPTIONS_GHC -fno-warn-tabs #-}
module Utility.Misc (
hGetContentsStrict,
readFileStrict,
separate,
separate',
separateEnd',
firstLine,
firstLine',
segment,
segmentDelim,
massReplace,
hGetSomeString,
exitBool,
prop_segment_regressionTest,
) where
import System.IO
import Control.Monad
import Foreign
import Data.Char
import Data.List
import System.Exit
import Control.Applicative
import qualified Data.ByteString as S
import Prelude
{- A version of hgetContents that is not lazy. Ensures file is
- all read before it gets closed. -}
hGetContentsStrict :: Handle -> IO String
hGetContentsStrict = hGetContents >=> \s -> length s `seq` return s
{- A version of readFile that is not lazy. -}
readFileStrict :: FilePath -> IO String
readFileStrict = readFile >=> \s -> length s `seq` return s
{- Like break, but the item matching the condition is not included
- in the second result list.
-
- separate (== ':') "foo:bar" = ("foo", "bar")
- separate (== ':') "foobar" = ("foobar", "")
-}
separate :: (a -> Bool) -> [a] -> ([a], [a])
separate c l = unbreak $ break c l
where
unbreak r@(a, b)
| null b = r
| otherwise = (a, tail b)
separate' :: (Word8 -> Bool) -> S.ByteString -> (S.ByteString, S.ByteString)
separate' c l = unbreak $ S.break c l
where
unbreak r@(a, b)
| S.null b = r
| otherwise = (a, S.tail b)
separateEnd' :: (Word8 -> Bool) -> S.ByteString -> (S.ByteString, S.ByteString)
separateEnd' c l = unbreak $ S.breakEnd c l
where
unbreak r@(a, b)
| S.null a = r
| otherwise = (S.init a, b)
{- Breaks out the first line. -}
firstLine :: String -> String
firstLine = takeWhile (/= '\n')
firstLine' :: S.ByteString -> S.ByteString
firstLine' = S.takeWhile (/= nl)
where
nl = fromIntegral (ord '\n')
{- Splits a list into segments that are delimited by items matching
- a predicate. (The delimiters are not included in the segments.)
- Segments may be empty. -}
segment :: (a -> Bool) -> [a] -> [[a]]
segment p l = map reverse $ go [] [] l
where
go c r [] = reverse $ c:r
go c r (i:is)
| p i = go [] (c:r) is
| otherwise = go (i:c) r is
prop_segment_regressionTest :: Bool
prop_segment_regressionTest = all id
-- Even an empty list is a segment.
[ segment (== "--") [] == [[]]
-- There are two segements in this list, even though the first is empty.
, segment (== "--") ["--", "foo", "bar"] == [[],["foo","bar"]]
]
{- Includes the delimiters as segments of their own. -}
segmentDelim :: (a -> Bool) -> [a] -> [[a]]
segmentDelim p l = map reverse $ go [] [] l
where
go c r [] = reverse $ c:r
go c r (i:is)
| p i = go [] ([i]:c:r) is
| otherwise = go (i:c) r is
{- Replaces multiple values in a string.
-
- Takes care to skip over just-replaced values, so that they are not
- mangled. For example, massReplace [("foo", "new foo")] does not
- replace the "new foo" with "new new foo".
-}
massReplace :: [(String, String)] -> String -> String
massReplace vs = go [] vs
where
go acc _ [] = concat $ reverse acc
go acc [] (c:cs) = go ([c]:acc) vs cs
go acc ((val, replacement):rest) s
| val `isPrefixOf` s =
go (replacement:acc) vs (drop (length val) s)
| otherwise = go acc rest s
{- Wrapper around hGetBufSome that returns a String.
-
- The null string is returned on eof, otherwise returns whatever
- data is currently available to read from the handle, or waits for
- data to be written to it if none is currently available.
-
- Note on encodings: The normal encoding of the Handle is ignored;
- each byte is converted to a Char. Not unicode clean!
-}
hGetSomeString :: Handle -> Int -> IO String
hGetSomeString h sz = do
fp <- mallocForeignPtrBytes sz
len <- withForeignPtr fp $ \buf -> hGetBufSome h buf sz
map (chr . fromIntegral) <$> withForeignPtr fp (peekbytes len)
where
peekbytes :: Int -> Ptr Word8 -> IO [Word8]
peekbytes len buf = mapM (peekElemOff buf) [0..pred len]
exitBool :: Bool -> IO a
exitBool False = exitFailure
exitBool True = exitSuccess