static: fix the build on GHC 7.4

There were two build issues on GHC 7.4: using atomicModifyIORef'
and ByteString.Lazy.toStrict, both of which were missing.  These
are now fixed.

In addition, looking at the IORef code more closely,
we want the quite a bit of strictness in the IORef.
The common case is that the widget content already exists in the map
(every reload of a page will call embedStaticContent), but until we
force the map the thunks holding the duplicated generated content will
be kept around, leaking memory.  This will be the common situation since
the vast majority of the time the content already exists.  Since
the containers module does not have a strict map until 0.5, use
unordered containers which does have a strict map.

yesod-static/Yesod/EmbeddedStatic.hs

@@ -67,7 +67,7 @@ import Yesod.Core.Types
           )
 import qualified Data.ByteString.Lazy as BL
 import qualified Data.Text as T
-import qualified Data.Map as M
+import qualified Data.HashMap.Strict as M
 import qualified WaiAppStatic.Storage.Embedded as Static
 
 import Yesod.EmbeddedStatic.Types

yesod-static/Yesod/EmbeddedStatic/Internal.hs

@@ -3,6 +3,7 @@
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE TupleSections #-}
 {-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE CPP #-}
 module Yesod.EmbeddedStatic.Internal (
       EmbeddedStatic(..)
     , Route(..)
@@ -34,16 +35,26 @@ import Yesod.Core
 import qualified Data.ByteString.Lazy as BL
 import qualified Data.Text as T
 import qualified Data.Text.Encoding as T
-import qualified Data.Map as M
+import qualified Data.HashMap.Strict as M
 import qualified WaiAppStatic.Storage.Embedded as Static
 
 import Yesod.Static (base64md5)
 import Yesod.EmbeddedStatic.Types
 
+#if !MIN_VERSION_base(4,6,0)
+-- copied from base
+atomicModifyIORef' :: IORef a -> (a -> (a,b)) -> IO b
+atomicModifyIORef' ref f = do
+    b <- atomicModifyIORef ref
+            (\x -> let (a, b) = f x
+                    in (a, a `seq` b))
+    b `seq` return b
+#endif
+
 -- | The subsite for the embedded static file server.
 data EmbeddedStatic = EmbeddedStatic {
     stApp :: !Application
-  , widgetFiles :: !(IORef (M.Map T.Text File))
+  , widgetFiles :: !(IORef (M.HashMap T.Text File))
 }
 
 instance RenderRoute EmbeddedStatic where

yesod-static/test/EmbedProductionTest.hs

@@ -15,7 +15,8 @@ import Yesod.EmbeddedStatic
 import Yesod.Test
 import qualified Data.ByteString as B
 import qualified Data.ByteString.Lazy as BL
-import qualified Data.Text.Encoding as T
+import qualified Data.Text.Lazy as TL
+import qualified Data.Text.Lazy.Encoding as TL
 
 mkEmbeddedStatic False "eProduction" [testGen]
 
@@ -110,7 +111,7 @@ embedProductionSpecs = yesodSpec (MyApp eProduction) $ do
             [script] <- htmlQuery "script"
             let src = BL.takeWhile (/= 34) $ BL.drop 1 $ BL.dropWhile (/= 34) script -- 34 is "
 
-            get $ T.decodeUtf8 $ BL.toStrict src
+            get $ TL.toStrict $ TL.decodeUtf8 src
             statusIs 200
             hasCacheControl
             assertHeader "Content-Type" "application/javascript"

yesod-static/yesod-static.cabal

@@ -52,6 +52,7 @@ library
                    , process-conduit       >= 1.0      && < 1.1
                    , filepath              >= 1.3
                    , resourcet             >= 0.4
+                   , unordered-containers  >= 0.2
 
     exposed-modules: Yesod.Static
                      Yesod.EmbeddedStatic
@@ -101,6 +102,7 @@ test-suite tests
                    , process-conduit
                    , filepath
                    , resourcet
+                   , unordered-containers
 
     ghc-options:     -Wall