compiler: refactor transform stages

1 files changed, 104 insertions, 0 deletions

diff --git a/compiler/src/Files.hs b/compiler/src/Files.hs
new file mode 100644
index 0000000..7948842
--- /dev/null
+++ b/compiler/src/Files.hs
@@ -0,0 +1,104 @@
+{-# LANGUAGE DuplicateRecordFields, DeriveGeneric #-}
+
+-- ldgallery - A static generator which turns a collection of tagged
+--             pictures into a searchable web gallery.
+--
+-- Copyright (C) 2019  Pacien TRAN-GIRARD
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU Affero General Public License as
+-- published by the Free Software Foundation, either version 3 of the
+-- License, or (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU Affero General Public License for more details.
+--
+-- You should have received a copy of the GNU Affero General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+
+module Files
+  ( FileName, LocalPath, WebPath, Path
+  , (</>), (</), (/>), localPath, webPath
+  , FSNode(..), AnchoredFSNode(..)
+  , nodePath, nodeName, isHidden, flatten, filterDir, readDirectory
+  ) where
+
+
+import Control.Monad (filterM, mapM)
+import Data.Bool (bool)
+import Data.List (isPrefixOf, length, deleteBy)
+import Data.Function ((&))
+import System.Directory (doesDirectoryExist, listDirectory)
+import qualified System.FilePath
+import qualified System.FilePath.Posix
+import Utils
+
+
+type FileName = String
+type LocalPath = String
+type WebPath = String
+
+ -- | Reversed path component list
+type Path = [FileName]
+
+(</>) :: Path -> Path -> Path
+l </> r = r ++ l
+
+(</) :: Path -> FileName -> Path
+path </ file = file:path
+
+(/>) :: FileName -> Path -> Path
+file /> path = path ++ [file]
+
+localPath :: Path -> LocalPath
+localPath = System.FilePath.joinPath . reverse
+
+webPath :: Path -> WebPath
+webPath = System.FilePath.Posix.joinPath . reverse
+
+
+data FSNode = File Path | Dir Path [FSNode] deriving Show
+data AnchoredFSNode = AnchoredFSNode
+  { anchor :: LocalPath
+  , root :: FSNode } deriving Show
+
+nodePath :: FSNode -> Path
+nodePath (File path) = path
+nodePath (Dir path _) = path
+
+nodeName :: FSNode -> FileName
+nodeName = head . nodePath
+
+isHidden :: FSNode -> Bool
+isHidden node = "." `isPrefixOf` filename && length filename > 1
+  where filename = nodeName node
+
+flatten :: FSNode -> [FSNode]
+flatten file@(File _) = [file]
+flatten dir@(Dir _ childs) = dir:(concatMap flatten childs)
+
+-- | Filters a dir tree. The root is always returned.
+filterDir :: (FSNode -> Bool) -> FSNode -> FSNode
+filterDir _ file@(File _) = file
+filterDir cond (Dir path childs) =
+  filter cond childs & map (filterDir cond) & Dir path
+
+readDirectory :: LocalPath -> IO AnchoredFSNode
+readDirectory root = mkNode [""] >>= return . AnchoredFSNode root
+  where
+    mkNode :: Path -> IO FSNode
+    mkNode path =
+      (doesDirectoryExist $ localPath (root /> path))
+      >>= bool (mkFileNode path) (mkDirNode path)
+
+    mkFileNode :: Path -> IO FSNode
+    mkFileNode path = return $ File path
+
+    mkDirNode :: Path -> IO FSNode
+    mkDirNode path =
+      (listDirectory $ localPath (root /> path))
+      >>= mapM (mkNode . ((</) path))
+      >>= return . Dir path