1 files changed, 26 insertions, 9 deletions
diff --git a/src/Text/Pandoc/MediaBag.hs b/src/Text/Pandoc/MediaBag.hs
index 4a9b4efa1..a65f315fc 100644
--- a/src/Text/Pandoc/MediaBag.hs
+++ b/src/Text/Pandoc/MediaBag.hs
@@ -15,6 +15,7 @@ Definition of a MediaBag object to hold binary resources, and an
 interface for interacting with it.
 -}
 module Text.Pandoc.MediaBag (
+                     MediaItem(..),
                      MediaBag,
                      deleteMedia,
                      lookupMedia,
@@ -28,15 +29,23 @@ import qualified Data.Map as M
 import Data.Maybe (fromMaybe)
 import Data.Typeable (Typeable)
 import System.FilePath
-import Text.Pandoc.MIME (MimeType, getMimeTypeDef)
+import Text.Pandoc.MIME (MimeType, getMimeTypeDef, extensionFromMimeType)
 import Data.Text (Text)
 import qualified Data.Text as T
+import Data.Digest.Pure.SHA (sha1, showDigest)
+
+data MediaItem =
+  MediaItem
+  { mediaMimeType :: MimeType
+  , mediaPath :: FilePath
+  , mediaContents :: BL.ByteString
+  } deriving (Eq, Ord, Show, Data, Typeable)
 
 -- | A container for a collection of binary resources, with names and
 -- mime types.  Note that a 'MediaBag' is a Monoid, so 'mempty'
 -- can be used for an empty 'MediaBag', and '<>' can be used to append
 -- two 'MediaBag's.
-newtype MediaBag = MediaBag (M.Map Text (MimeType, BL.ByteString))
+newtype MediaBag = MediaBag (M.Map Text MediaItem)
         deriving (Semigroup, Monoid, Data, Typeable)
 
 instance Show MediaBag where
@@ -62,26 +71,34 @@ insertMedia :: FilePath       -- ^ relative path and canonical name of resource
             -> MediaBag
             -> MediaBag
 insertMedia fp mbMime contents (MediaBag mediamap) =
-  MediaBag (M.insert (canonicalize fp) (mime, contents) mediamap)
-  where mime = fromMaybe fallback mbMime
+  MediaBag (M.insert (canonicalize fp) mediaItem mediamap)
+  where mediaItem = MediaItem{ mediaPath = showDigest (sha1 contents) <>
+                                 "." <> ext
+                             , mediaContents = contents
+                             , mediaMimeType = mt }
         fallback = case takeExtension fp of
                         ".gz" -> getMimeTypeDef $ dropExtension fp
                         _     -> getMimeTypeDef fp
+        mt = fromMaybe fallback mbMime
+        ext = maybe (takeExtension fp) T.unpack $ extensionFromMimeType mt
+
 
 -- | Lookup a media item in a 'MediaBag', returning mime type and contents.
 lookupMedia :: FilePath
             -> MediaBag
-            -> Maybe (MimeType, BL.ByteString)
+            -> Maybe MediaItem
 lookupMedia fp (MediaBag mediamap) = M.lookup (canonicalize fp) mediamap
 
 -- | Get a list of the file paths stored in a 'MediaBag', with
 -- their corresponding mime types and the lengths in bytes of the contents.
 mediaDirectory :: MediaBag -> [(FilePath, MimeType, Int)]
 mediaDirectory (MediaBag mediamap) =
-  M.foldrWithKey (\fp (mime,contents) ->
-      ((T.unpack fp, mime, fromIntegral (BL.length contents)):)) [] mediamap
+  M.foldrWithKey (\fp item ->
+      ((T.unpack fp, mediaMimeType item,
+        fromIntegral (BL.length (mediaContents item))):)) [] mediamap
 
 mediaItems :: MediaBag -> [(FilePath, MimeType, BL.ByteString)]
 mediaItems (MediaBag mediamap) =
-  M.foldrWithKey (\fp (mime,contents) ->
-      ((T.unpack fp, mime, contents):)) [] mediamap
+  M.foldrWithKey (\fp item ->
+      ((T.unpack fp, mediaMimeType item, mediaContents item):))
+     [] mediamap