Speedup of factor 4 by switching to the Data.Binary library for serialization.

hakyll.cabal

@@ -34,7 +34,8 @@ library
                    mtl >= 1.1,
                    old-locale >= 1,
                    time >= 1,
-                   parallel >= 2
+                   parallel >= 2,
+                   binary >= 0.5
   exposed-modules: Text.Hakyll
                    Text.Hakyll.Hakyll
                    Text.Hakyll.Render

src/Text/Hakyll/Internal/Cache.hs

@@ -6,19 +6,17 @@ module Text.Hakyll.Internal.Cache
 import Control.Monad.Reader (liftIO)
 import Text.Hakyll.Hakyll (Hakyll)
 import Text.Hakyll.File
+import Data.Binary
 
-storeInCache :: (Show a) => a -> FilePath -> Hakyll ()
+storeInCache :: (Binary a) => a -> FilePath -> Hakyll ()
 storeInCache value path = do
     cachePath <- toCache path
     makeDirectories cachePath
-    liftIO $ writeFile cachePath (show value)
+    liftIO $ encodeFile cachePath value
 
-getFromCache :: (Read a) => FilePath -> Hakyll (Maybe a)
+getFromCache :: (Binary a) => FilePath -> Hakyll (Maybe a)
 getFromCache path = do
     cachePath <- toCache path
     valid <- isMoreRecent cachePath [path]
-    if valid then liftIO (getFromCache' cachePath) >>= return . Just
+    if valid then liftIO (decodeFile cachePath) >>= return . Just
              else return Nothing
-  where
-    getFromCache' cachePath = do c <- readFile cachePath
-                                 return (read c)

src/Text/Hakyll/Page.hs

@@ -11,12 +11,14 @@ import qualified Data.Map as M
 import Data.List (isPrefixOf)
 import Data.Char (isSpace)
 import Data.Maybe (fromMaybe)
-import Control.Parallel.Strategies (rdeepseq, ($|))
+import Control.Monad (liftM)
 import Control.Monad.Reader (liftIO)
+import Control.Parallel.Strategies (rdeepseq, ($|))
 import System.FilePath (takeExtension)
 import System.IO
 
 import Text.Pandoc
+import Data.Binary
 
 import Text.Hakyll.Internal.Cache
 import Text.Hakyll.Hakyll (Hakyll)
@@ -148,3 +150,8 @@ instance Renderable Page where
     getDependencies = (:[]) . getPagePath
     getURL = getPageURL
     toContext (Page page) = return page
+
+-- Make pages serializable.
+instance Binary Page where
+    put (Page context) = put $ M.toList context
+    get = liftM (Page . M.fromList) get