Split git repo source handler into sane small functions

src/Data/Git/Local.hs

@@ -14,44 +14,45 @@
  -}
 
 module Data.Git.Local
-    ( initRepo
+    ( -- * Initialize repo
+      createRepo
+      -- * View repo content
+    , EntObjType (..)
+    , TreeRows
+    , PathView (..)
+    , viewPath
     )
 where
 
 import Prelude
 
 import Control.Monad (when)
+import Data.Byteable (toBytes)
+import Data.Git
+import Data.Git.Harder
+import Data.Text (Text)
+import Data.Text.Encoding (decodeUtf8With)
+import Data.Text.Encoding.Error (lenientDecode)
 import System.Directory.Tree
 
 import qualified Data.ByteString as B (ByteString, writeFile)
-
-initialConfig :: B.ByteString
-initialConfig =
-    "[core]\n\
-    \    repositoryformatversion = 0\n\
-    \    filemode = true\n\
-    \    bare = true"
-
-initialDescription :: B.ByteString
-initialDescription =
-    "Unnamed repository; edit this file to name the repository."
-
-initialHead :: B.ByteString
-initialHead = "ref: refs/heads/master"
-
-initialExclude :: B.ByteString
-initialExclude = ""
+import qualified Data.ByteString.Lazy as BL (ByteString)
 
 initialRepoTree :: FileName -> DirTree B.ByteString
 initialRepoTree repo =
     Dir repo
         [ Dir "branches" []
-        , File "config" initialConfig
-        , File "description" initialDescription
-        , File "HEAD" initialHead
+        , File "config"
+            "[core]\n\
+            \    repositoryformatversion = 0\n\
+            \    filemode = true\n\
+            \    bare = true"
+        , File "description"
+            "Unnamed repository; edit this file to name the repository."
+        , File "HEAD" "ref: refs/heads/master"
         , Dir "hooks" []
         , Dir "info"
-            [ File "exclude" initialExclude
+            [ File "exclude" ""
             ]
         , Dir "objects"
             [ Dir "info" []
@@ -68,14 +69,41 @@ initialRepoTree repo =
 -- Currently in the @hit@ package, i.e. version 0.6.3, the initRepo function
 -- creates a directory which the git executable doesn't recognize as a git
 -- repository. The version here creates a properly initialized repo.
-initRepo
+createRepo
     :: FilePath
     -- ^ Parent directory which already exists
     -> String
     -- ^ Name of new repo, i.e. new directory to create under the parent
     -> IO ()
-initRepo path name = do
+createRepo path name = do
     let tree = path :/ initialRepoTree name
     result <- writeDirectoryWith B.writeFile tree
     let errs = failures $ dirTree result
     when (not . null $ errs) $ error $ show errs
+
+data EntObjType = EntObjBlob | EntObjTree
+
+type TreeRows = [(ModePerm, ObjId, Text, EntObjType)]
+
+data PathView
+    = RootView TreeRows
+    | TreeView Text ObjId TreeRows
+    | BlobView Text ObjId BL.ByteString
+
+viewPath :: Git -> Tree -> EntPath -> IO PathView
+viewPath git root path = do
+    let toEnt False = EntObjBlob
+        toEnt True  = EntObjTree
+        toText = decodeUtf8With lenientDecode . toBytes
+        adapt (perm, oid, name, isTree) =
+            (perm, oid, toText name, toEnt isTree)
+        mkRows t = map adapt <$> viewTree git t
+    mno <- resolveTreePath git root path
+    case mno of
+        Nothing          -> RootView <$> mkRows root
+        Just (name, oid) -> do
+            let nameT = toText name
+            target <- getEntryObject_ git oid
+            case target of
+                Left blob  -> return $ BlobView nameT oid (blobGetContent blob)
+                Right tree -> TreeView nameT oid <$> mkRows tree