Add modification time access for resources

3 files changed, 22 insertions, 6 deletions

diff --git a/src/Hakyll/Core/Resource/Provider.hs b/src/Hakyll/Core/Resource/Provider.hs
index 808719a..c3bc9ab 100644
--- a/src/Hakyll/Core/Resource/Provider.hs
+++ b/src/Hakyll/Core/Resource/Provider.hs
@@ -23,6 +23,7 @@ import Control.Concurrent (MVar, readMVar, modifyMVar_, newMVar)
 import Data.Map (Map)
 import qualified Data.Map as M
 
+import Data.Time (UTCTime)
 import qualified Crypto.Hash.MD5 as MD5
 import qualified Data.ByteString as B
 import qualified Data.ByteString.Lazy as LB
@@ -34,13 +35,15 @@ import Hakyll.Core.Resource
 --
 data ResourceProvider = ResourceProvider
     { -- | A list of all resources this provider is able to provide
-      resourceList          :: [Resource]
+      resourceList             :: [Resource]
     , -- | Retrieve a certain resource as string
-      resourceString        :: Resource -> IO String
+      resourceString           :: Resource -> IO String
     , -- | Retrieve a certain resource as lazy bytestring
-      resourceLBS           :: Resource -> IO LB.ByteString
+      resourceLBS              :: Resource -> IO LB.ByteString
+    , -- | Check when a resource was last modified
+      resourceModificationTime :: Resource -> IO UTCTime
     , -- | Cache keeping track of modified items
-      resourceModifiedCache :: MVar (Map Resource Bool)
+      resourceModifiedCache    :: MVar (Map Resource Bool)
     }
 
 -- | Create a resource provider
@@ -48,8 +51,9 @@ data ResourceProvider = ResourceProvider
 makeResourceProvider :: [Resource]                      -- ^ Resource list
                      -> (Resource -> IO String)         -- ^ String reader
                      -> (Resource -> IO LB.ByteString)  -- ^ ByteString reader
+                     -> (Resource -> IO UTCTime)        -- ^ Time checker
                      -> IO ResourceProvider             -- ^ Resulting provider
-makeResourceProvider l s b = ResourceProvider l s b <$> newMVar M.empty
+makeResourceProvider l s b t = ResourceProvider l s b t <$> newMVar M.empty
 
 -- | Check if a given identifier has a resource
 --
diff --git a/src/Hakyll/Core/Resource/Provider/Dummy.hs b/src/Hakyll/Core/Resource/Provider/Dummy.hs
index 9f15178..dad7b0b 100644
--- a/src/Hakyll/Core/Resource/Provider/Dummy.hs
+++ b/src/Hakyll/Core/Resource/Provider/Dummy.hs
@@ -7,9 +7,10 @@ module Hakyll.Core.Resource.Provider.Dummy
 import Data.Map (Map)
 import qualified Data.Map as M
 
+import Data.Time (getCurrentTime)
+import Data.ByteString.Lazy (ByteString)
 import qualified Data.Text.Lazy as TL
 import qualified Data.Text.Lazy.Encoding as TL
-import Data.ByteString.Lazy (ByteString)
 
 import Hakyll.Core.Resource
 import Hakyll.Core.Resource.Provider
@@ -21,3 +22,4 @@ dummyResourceProvider vfs = makeResourceProvider
     (map Resource (M.keys vfs))
     (return . TL.unpack . TL.decodeUtf8 . (vfs M.!) . unResource)
     (return . (vfs M.!) . unResource)
+    (const getCurrentTime)
diff --git a/src/Hakyll/Core/Resource/Provider/File.hs b/src/Hakyll/Core/Resource/Provider/File.hs
index c0e306a..abb7ebe 100644
--- a/src/Hakyll/Core/Resource/Provider/File.hs
+++ b/src/Hakyll/Core/Resource/Provider/File.hs
@@ -6,6 +6,10 @@ module Hakyll.Core.Resource.Provider.File
 
 import Control.Applicative ((<$>))
 
+import Data.Time (readTime)
+import System.Directory (getModificationTime)
+import System.Locale (defaultTimeLocale)
+import System.Time (formatCalendarTime, toCalendarTime)
 import qualified Data.ByteString.Lazy as LB
 
 import Hakyll.Core.Resource
@@ -22,3 +26,9 @@ fileResourceProvider configuration = do
         getRecursiveContents False "."
     makeResourceProvider list (readFile . unResource)
                               (LB.readFile . unResource)
+                              mtime
+  where
+    mtime (Resource r) = do
+        ct <- toCalendarTime =<< getModificationTime r
+        let str = formatCalendarTime defaultTimeLocale "%s" ct
+        return $ readTime defaultTimeLocale "%s" str