undo command

This commit was sponsored by Andrew Cant.

Git/DiffTree.hs

@@ -7,10 +7,12 @@
 
 module Git.DiffTree (
 	DiffTreeItem(..),
+	isDiffOf,
 	diffTree,
 	diffTreeRecursive,
 	diffIndex,
 	diffWorkTree,
+	diffLog,
 ) where
 
 import Numeric
@@ -33,6 +35,13 @@ data DiffTreeItem = DiffTreeItem
 	, file :: TopFilePath
 	} deriving Show
 
+{- Checks if the DiffTreeItem modifies a file with a given name
+ - or under a directory by that name. -}
+isDiffOf :: DiffTreeItem -> TopFilePath -> Bool
+isDiffOf diff f = case getTopFilePath f of
+	"" -> True -- top of repo contains all
+	d -> d `dirContains` getTopFilePath (file diff)
+
 {- Diffs two tree Refs. -}
 diffTree :: Ref -> Ref -> Repo -> IO ([DiffTreeItem], IO Bool)
 diffTree src dst = getdiff (Param "diff-tree")
@@ -66,16 +75,23 @@ diffIndex' ref params repo =
 		, return ([], return True)
 		)
 
+{- Runs git log in --raw mode to get the changes that were made in
+ - a particular commit. The output format is adjusted to be the same
+ - as diff-tree --raw._-}
+diffLog :: [CommandParam] -> Repo -> IO ([DiffTreeItem], IO Bool)
+diffLog params = getdiff (Param "log")
+	(Param "-n1" : Param "--abbrev=40" : Param "--pretty=format:" : params)
+
 getdiff :: CommandParam -> [CommandParam] -> Repo -> IO ([DiffTreeItem], IO Bool)
 getdiff command params repo = do
 	(diff, cleanup) <- pipeNullSplit ps repo
-	return (parseDiffTree diff, cleanup)
+	return (parseDiffRaw diff, cleanup)
   where
 	ps = command : Params "-z --raw --no-renames -l0" : params
 
-{- Parses diff-tree output. -}
-parseDiffTree :: [String] -> [DiffTreeItem]
-parseDiffTree l = go l []
+{- Parses --raw output used by diff-tree and git-log. -}
+parseDiffRaw :: [String] -> [DiffTreeItem]
+parseDiffRaw l = go l []
   where
 	go [] c = c
 	go (info:f:rest) c = go rest (mk info f : c)