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diff --git a/src/Hakyll/Core/Util/File.hs b/src/Hakyll/Core/Util/File.hs
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+-- | A module containing various file utility functions
+--
+module Hakyll.Core.Util.File
+    ( makeDirectories
+    , getRecursiveContents
+    , isFileObsolete
+    , isFileInternal
+    ) where
+
+import Control.Applicative ((<$>))
+import System.Time (ClockTime)
+import Control.Monad (forM, filterM)
+import Data.List (isPrefixOf)
+import System.Directory ( createDirectoryIfMissing, doesDirectoryExist
+                        , doesFileExist, getModificationTime
+                        , getDirectoryContents
+                        )
+import System.FilePath ( normalise, takeDirectory, splitPath
+                       , dropTrailingPathSeparator, (</>)
+                       )
+
+import Hakyll.Core.Configuration
+
+-- | Given a path to a file, try to make the path writable by making
+--   all directories on the path.
+--
+makeDirectories :: FilePath -> IO ()
+makeDirectories = createDirectoryIfMissing True . takeDirectory
+
+-- | Get all contents of a directory. Note that files starting with a dot (.)
+-- will be ignored.
+--
+getRecursiveContents :: Bool           -- ^ Include directories?
+                     -> FilePath       -- ^ Directory to search
+                     -> IO [FilePath]  -- ^ List of files found
+getRecursiveContents includeDirs topdir = do
+    topdirExists <- doesDirectoryExist topdir
+    if not topdirExists
+        then return []
+        else do
+            names <- filter isProper <$> getDirectoryContents topdir
+            paths <- forM names $ \name -> do
+                let path = normalise $ topdir </> name
+                isDirectory <- doesDirectoryExist path
+                if isDirectory then getRecursiveContents includeDirs path
+                               else return [path]
+            return $ if includeDirs then topdir : concat paths
+                                    else concat paths
+  where
+    isProper = not . (== ".") . take 1
+
+-- | Check if a timestamp is obsolete compared to the timestamps of a number of
+-- files. When they are no files, it is never obsolete.
+--
+isObsolete :: ClockTime    -- ^ The time to check.
+           -> [FilePath]   -- ^ Dependencies of the cached file.
+           -> IO Bool
+isObsolete _ [] = return False
+isObsolete timeStamp depends = do
+    depends' <- filterM doesFileExist depends
+    dependsModified <- mapM getModificationTime depends'
+    return (timeStamp < maximum dependsModified)
+
+-- | Check if a file is obsolete, given it's dependencies. When the file does
+-- not exist, it is always obsolete. Other wise, it is obsolete if any of it's
+-- dependencies has a more recent modification time than the file.
+--
+isFileObsolete :: FilePath    -- ^ The cached file
+               -> [FilePath]  -- ^ Dependencies of the cached file
+               -> IO Bool
+isFileObsolete file depends = do
+    exists <- doesFileExist file
+    if not exists
+        then return True
+        else do timeStamp <- getModificationTime file
+                isObsolete timeStamp depends
+
+-- | Check if a file is meant for Hakyll internal use, i.e. if it is located in
+-- the destination or store directory
+--
+isFileInternal :: HakyllConfiguration  -- ^ Configuration
+               -> FilePath             -- ^ File to check
+               -> Bool                 -- ^ If the given file is internal
+isFileInternal configuration file =
+    any (`isPrefixOf` split file) dirs
+  where
+    split = map dropTrailingPathSeparator . splitPath
+    dirs = map (split . ($ configuration)) [ destinationDirectory
+                                           , storeDirectory
+                                           ]