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, 3 insertions, 1 deletions

diff --git a/src/Text/Pandoc/Writers/Powerpoint/Output.hs b/src/Text/Pandoc/Writers/Powerpoint/Output.hs
index 8554db622..cd092969b 100644
--- a/src/Text/Pandoc/Writers/Powerpoint/Output.hs
+++ b/src/Text/Pandoc/Writers/Powerpoint/Output.hs
@@ -29,6 +29,7 @@ import Data.Time.Clock (UTCTime)
 import Data.Time.Clock.POSIX (utcTimeToPOSIXSeconds, posixSecondsToUTCTime)
 import System.FilePath.Posix (splitDirectories, splitExtension, takeExtension)
 import Text.XML.Light
+import Text.Pandoc.XMLParser (parseXMLElement)
 import Text.Pandoc.Definition
 import qualified Text.Pandoc.UTF8 as UTF8
 import Text.Pandoc.Class.PandocMonad (PandocMonad)
@@ -77,7 +78,8 @@ getPresentationSize :: Archive -> Archive -> Maybe (Integer, Integer)
 getPresentationSize refArchive distArchive = do
   entry <- findEntryByPath "ppt/presentation.xml" refArchive  `mplus`
            findEntryByPath "ppt/presentation.xml" distArchive
-  presElement <- parseXMLDoc $ UTF8.toStringLazy $ fromEntry entry
+  presElement <- either (const Nothing) return $
+                   parseXMLElement $ UTF8.toTextLazy $ fromEntry entry
   let ns = elemToNameSpaces presElement
   sldSize <- findChild (elemName ns "p" "sldSz") presElement
   cxS <- findAttr (QName "cx" Nothing Nothing) sldSize