fdo#68750: ensure that GetSuggestedEndOfSentence makes progress

Checking a string of 17399 spaces takes 20 seconds here in
GrammarCheckingIterator::GetSuggestedEndOfSentence() because
BreakIterator_Unicode::endOfSentence() will always return
0 as a result regardless of what nStartPos it gets.

Change-Id: Id02440a91d7015c2896e387854445ee5383092fa
(cherry picked from commit b23999755a865a277c29adfc1dc0c249275bfd7e)
Reviewed-on: https://gerrit.libreoffice.org/5758
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/linguistic/source/gciterator.cxx b/linguistic/source/gciterator.cxx
index 4c08a9eed79d..f12b6f2136aa 100644
--- a/linguistic/source/gciterator.cxx
+++ b/linguistic/source/gciterator.cxx
@@ -754,13 +754,23 @@ sal_Int32 GrammarCheckingIterator::GetSuggestedEndOfSentence(
         m_xBreakIterator = i18n::BreakIterator::create(xContext);
     }
     sal_Int32 nTextLen = rText.getLength();
-    sal_Int32 nEndPosition;
+    sal_Int32 nEndPosition(0);
     sal_Int32 nTmpStartPos = nSentenceStartPos;
     do
     {
+        sal_Int32 const nPrevEndPosition(nEndPosition);
         nEndPosition = nTextLen;
         if (nTmpStartPos < nTextLen)
+        {
             nEndPosition = m_xBreakIterator->endOfSentence( rText, nTmpStartPos, rLocale );
+            if (nEndPosition <= nPrevEndPosition)
+            {
+                // fdo#68750 if there's no progress at all then presumably
+                // there's no end of sentence in this paragraph so just
+                // set the end position to end of paragraph
+                nEndPosition = nTextLen;
+            }
+        }
         if (nEndPosition < 0)
             nEndPosition = nTextLen;