git-repair (1.20131122) unstable; urgency=low

  * Added test mode, which can be used to randomly corrupt test
    repositories, in reproducible ways, which allows easy
    corruption-driven-development.
  * Improve repair code in the case where the index file is corrupt,
    and this hides other problems.
  * Write a dummy .git/HEAD if the file is missing or corrupt, as
    git otherwise will not treat the repository as a git repo.
  * Improve fsck code to find badly corrupted objects that crash git fsck
    before it can complain about them.
  * Fixed crashes on bad file encodings.
  * Can now run 10000 tests (git-repair --test -n 10000 --force)
    with 0 failures.

# imported from the archive

1 files changed, 39 insertions, 0 deletions

diff --git a/Git/Sha.hs b/Git/Sha.hs
new file mode 100644
index 0000000..ee1b6d6
--- /dev/null
+++ b/Git/Sha.hs
@@ -0,0 +1,39 @@
+{- git SHA stuff
+ -
+ - Copyright 2011 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Git.Sha where
+
+import Common
+import Git.Types
+
+{- Runs an action that causes a git subcommand to emit a Sha, and strips
+ - any trailing newline, returning the sha. -}
+getSha :: String -> IO String -> IO Sha
+getSha subcommand a = maybe bad return =<< extractSha <$> a
+  where
+	bad = error $ "failed to read sha from git " ++ subcommand
+
+{- Extracts the Sha from a string. There can be a trailing newline after
+ - it, but nothing else. -}
+extractSha :: String -> Maybe Sha
+extractSha s
+	| len == shaSize = val s
+	| len == shaSize + 1 && length s' == shaSize = val s'
+	| otherwise = Nothing
+  where
+	len = length s
+	s' = firstLine s
+	val v
+		| all (`elem` "1234567890ABCDEFabcdef") v = Just $ Ref v
+		| otherwise = Nothing
+
+{- Size of a git sha. -}
+shaSize :: Int
+shaSize = 40
+
+nullSha :: Ref		
+nullSha = Ref $ replicate shaSize '0'