Add new unexported module T.P.XMLParser.

This exports functions that uses xml-conduit's parser to
produce an xml-light Element or [Content].  This allows
existing pandoc code to use a better parser without
much modification.

The new parser is used in all places where xml-light's
parser was previously used.  Benchmarks show a significant
performance improvement in parsing XML-based formats
(especially ODT and FB2).

Note that the xml-light types use String, so the
conversion from xml-conduit types involves a lot
of extra allocation.  It would be desirable to
avoid that in the future by gradually switching
to using xml-conduit directly. This can be done
module by module.

The new parser also reports errors, which we report
when possible.

A new constructor PandocXMLError has been added to
PandocError in T.P.Error [API change].

Closes #7091, which was the main stimulus.

These changes revealed the need for some changes
in the tests.  The docbook-reader.docbook test
lacked definitions for the entities it used; these
have been added. And the docx golden tests have been
updated, because the new parser does not preserve
the order of attributes.

Add entity defs to docbook-reader.docbook.

Update golden tests for docx.

1 files changed, 8 insertions, 2 deletions

diff --git a/src/Text/Pandoc/Readers/OPML.hs b/src/Text/Pandoc/Readers/OPML.hs
index 5b8996025..bdadc4dd9 100644
--- a/src/Text/Pandoc/Readers/OPML.hs
+++ b/src/Text/Pandoc/Readers/OPML.hs
@@ -19,14 +19,18 @@ import Data.Generics
 import Data.Maybe (fromMaybe)
 import Data.Text (Text)
 import qualified Data.Text as T
+import qualified Data.Text.Lazy as TL
 import Text.HTML.TagSoup.Entity (lookupEntity)
 import Text.Pandoc.Builder
 import Text.Pandoc.Class.PandocMonad (PandocMonad)
 import Text.Pandoc.Options
+import Text.Pandoc.Error (PandocError(..))
 import Text.Pandoc.Readers.HTML (readHtml)
 import Text.Pandoc.Readers.Markdown (readMarkdown)
 import Text.Pandoc.Shared (crFilter, blocksToInlines')
 import Text.XML.Light
+import Text.Pandoc.XMLParser (parseXMLContents)
+import Control.Monad.Except (throwError)
 
 type OPML m = StateT OPMLState m
 
@@ -49,8 +53,10 @@ instance Default OPMLState where
 readOPML :: PandocMonad m => ReaderOptions -> Text -> m Pandoc
 readOPML opts inp  = do
   (bs, st') <- runStateT
-                 (mapM parseBlock $ normalizeTree $
-                    parseXML (T.unpack (crFilter inp))) def{ opmlOptions = opts }
+                 (case parseXMLContents (TL.fromStrict (crFilter inp)) of
+                     Left msg -> throwError $ PandocXMLError "" msg
+                     Right ns -> mapM parseBlock $ normalizeTree ns)
+                 def{ opmlOptions = opts }
   return $
     setTitle (opmlDocTitle st') $
     setAuthors (opmlDocAuthors st') $