Allow extracting data: URIs even in PandocPure (--sandbox).

These don't require IO, so we should allow it in sandboxed
mode.  Closes #10249.

src/Text/Pandoc/Class/IO.hs

@@ -62,7 +62,7 @@ import System.IO.Error
 import System.Random (StdGen)
 import Text.Pandoc.Class.CommonState (CommonState (..))
 import Text.Pandoc.Class.PandocMonad
-       (PandocMonad, getsCommonState, getMediaBag, report)
+       (PandocMonad, getsCommonState, getMediaBag, report, extractURIData)
 import Text.Pandoc.Definition (Pandoc, Inline (Image))
 import Text.Pandoc.Error (PandocError (..))
 import Text.Pandoc.Logging (LogMessage (..), messageVerbosity, showLogMessage)
@@ -128,14 +128,8 @@ newUniqueHash = hashUnique <$> liftIO Data.Unique.newUnique
 openURL :: (PandocMonad m, MonadIO m) => Text -> m (B.ByteString, Maybe MimeType)
 openURL u
  | Just (URI{ uriScheme = "data:",
-              uriPath = upath }) <- parseURI (T.unpack u) = do
-     let (mimespec, rest) = break (== ',') $ unEscapeString upath
-     let contents = UTF8.fromString $ drop 1 rest
-     case break (== ';') (filter (/= ' ') mimespec) of
-       (mime, ";base64") ->
-         return (decodeLenient contents, Just (T.pack mime))
-       (mime, _) ->
-         return (contents, Just (T.pack mime))
+              uriPath = upath }) <- parseURI (T.unpack u)
+     = pure $ extractURIData upath
  | otherwise = do
      let toReqHeader (n, v) = (CI.mk (UTF8.fromText n), UTF8.fromText v)
      customHeaders <- map toReqHeader <$> getsCommonState stRequestHeaders

src/Text/Pandoc/Class/PandocMonad.hs

@@ -335,8 +335,7 @@ downloadOrRead :: PandocMonad m
                -> m (B.ByteString, Maybe MimeType)
 downloadOrRead s = do
   sourceURL <- getsCommonState stSourceURL
-  case (sourceURL >>= parseURIReference' .
-                       ensureEscaped, ensureEscaped s) of
+  case (sourceURL >>= parseURIReference' . ensureEscaped, ensureEscaped s) of
     (Just u, s') -> -- try fetching from relative path at source
        case parseURIReference' s' of
             Just u' -> openURL $ T.pack $ show $ u' `nonStrictRelativeTo` u
@@ -348,8 +347,10 @@ downloadOrRead s = do
             Nothing -> openURL s' -- will throw error
     (Nothing, s') ->
        case parseURI (T.unpack s') of  -- requires absolute URI
-            Just u' | uriScheme u' == "file:" ->
-                 readLocalFile $ uriPathToPath (T.pack $ uriPath u')
+            Just URI{ uriScheme = "file:", uriPath = upath}
+              -> readLocalFile $ uriPathToPath (T.pack upath)
+            Just URI{ uriScheme = "data:", uriPath = upath}
+              -> pure $ extractURIData upath
             -- We don't want to treat C:/ as a scheme:
             Just u' | length (uriScheme u') > 2 -> openURL (T.pack $ show u')
             _ -> readLocalFile fp -- get from local file system