tdf#105417 sw hyphenation: avoid infinite loop on zero-length last line

This hang happened when the user executed Tools -> Language ->
Hyphenation -> Hyphenate All.

This problem is visible only if all of these conditions are met:
- a line in a paragraph has a word that already contains a soft-hyphen,
  but not at the position where the automatic hyphenation would insert
  it
- the last line ends with a word that can be hyphenated
- there is a fly frame in the document

In this case it happens during hyphenation that the layout has an
additional empty line at the end (which is removed by the time the
layout finishes), so we hit the case when SwTextFormatter::Hyphenate()
skips the "if( m_pCurr->PrtWidth() && m_pCurr->GetLen() )" block.

Normally hyphenation terminates when it iterates over the portions of the
line and no overrun nor any existing hyphen portion are seen, but in
this case that never happened. Fix the problem by terminating not only
when we reach the end of the portion iteration, but also when the
portion list is non-existing (has zero length).

Change-Id: I71d4b040a2d4692ae6eb92807dbbbb42b077a0f8
Reviewed-on: https://gerrit.libreoffice.org/33303
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>

5 files changed, 35 insertions, 2 deletions

diff --git a/sw/qa/extras/uiwriter/data/tdf105417.odt b/sw/qa/extras/uiwriter/data/tdf105417.odt
new file mode 100644
index 000000000000..d594d2a5aed5
--- /dev/null
+++ b/sw/qa/extras/uiwriter/data/tdf105417.odt
diff --git a/sw/qa/extras/uiwriter/uiwriter.cxx b/sw/qa/extras/uiwriter/uiwriter.cxx
index f984499decfd..e879cd22ee86 100644
--- a/sw/qa/extras/uiwriter/uiwriter.cxx
+++ b/sw/qa/extras/uiwriter/uiwriter.cxx
@@ -88,6 +88,7 @@
 #include <paratr.hxx>
 #include <drawfont.hxx>
 #include <txtfrm.hxx>
+#include <hyp.hxx>
 #include <editeng/svxenum.hxx>
 #include <comphelper/propertysequence.hxx>
 #include <sfx2/classificationhelper.hxx>
@@ -96,6 +97,7 @@
 #include <sfx2/dispatch.hxx>
 #include <comphelper/propertyvalue.hxx>
 #include <comphelper/configurationhelper.hxx>
+#include <editeng/unolingu.hxx>
 #include <config_features.h>
 
 static const char* const DATA_DIRECTORY = "/sw/qa/extras/uiwriter/data/";
@@ -222,6 +224,7 @@ public:
     void testTdf104814();
     void testTdf66405();
     void testTdf104492();
+    void testTdf105417();
 
     CPPUNIT_TEST_SUITE(SwUiWriterTest);
     CPPUNIT_TEST(testReplaceForward);
@@ -340,6 +343,7 @@ public:
     CPPUNIT_TEST(testTdf104814);
     CPPUNIT_TEST(testTdf66405);
     CPPUNIT_TEST(testTdf104492);
+    CPPUNIT_TEST(testTdf105417);
     CPPUNIT_TEST_SUITE_END();
 
 private:
@@ -4211,6 +4215,29 @@ void SwUiWriterTest::testTdf104492()
     assertXPath(pXmlDoc, "//page", 3);
 }
 
+void SwUiWriterTest::testTdf105417()
+{
+    SwDoc* pDoc = createDoc("tdf105417.odt");
+    CPPUNIT_ASSERT(pDoc);
+    SwView* pView = pDoc->GetDocShell()->GetView();
+    CPPUNIT_ASSERT(pView);
+    uno::Reference<linguistic2::XHyphenator> xHyphenator = LinguMgr::GetHyphenator();
+    CPPUNIT_ASSERT(xHyphenator.is());
+    // If there are no English hyphenation rules installed, we can't test
+    // hyphenation.
+    if (!xHyphenator->hasLocale(lang::Locale("en", "US", OUString())))
+        return;
+
+    uno::Reference<linguistic2::XLinguProperties> xLinguProperties(LinguMgr::GetLinguPropertySet());
+    // Automatic hyphenation means not opening a dialog, but going ahead
+    // non-interactively.
+    xLinguProperties->setIsHyphAuto(true);
+    SwHyphWrapper aWrap(pView, xHyphenator, /*bStart=*/false, /*bOther=*/true, /*bSelection=*/false);
+    // This never returned, it kept trying to hyphenate the last word
+    // (greenbacks) again and again.
+    aWrap.SpellDocument();
+}
+
 CPPUNIT_TEST_SUITE_REGISTRATION(SwUiWriterTest);
 CPPUNIT_PLUGIN_IMPLEMENT();
 
diff --git a/sw/source/core/text/txthyph.cxx b/sw/source/core/text/txthyph.cxx
index 369a22ae3b03..6b5bd8470648 100644
--- a/sw/source/core/text/txthyph.cxx
+++ b/sw/source/core/text/txthyph.cxx
@@ -197,6 +197,11 @@ bool SwTextFormatter::Hyphenate( SwInterHyphInfo &rHyphInf )
         if( !pPos )
             nWrdStart = 0;
     }
+    else
+        // In case the whole line is zero-length, that's the same situation as
+        // above when the portion iteration ends without explicitly breaking
+        // from the loop.
+        nWrdStart = 0;
 
     // Das alte LineLayout wird wieder eingestellt ...
     delete m_pCurr;
diff --git a/sw/source/uibase/inc/hyp.hxx b/sw/source/uibase/inc/hyp.hxx
index 24942e31c680..e12638fa6575 100644
--- a/sw/source/uibase/inc/hyp.hxx
+++ b/sw/source/uibase/inc/hyp.hxx
@@ -23,10 +23,11 @@
 #include <tools/link.hxx>
 #include <editeng/splwrap.hxx>
 #include <com/sun/star/linguistic2/XHyphenator.hpp>
+#include <swdllapi.h>
 
 class SwView;
 
-class SwHyphWrapper : public SvxSpellWrapper {
+class SW_DLLPUBLIC SwHyphWrapper : public SvxSpellWrapper {
 private:
     SwView* pView;
     sal_uInt16      nPageCount;     // page count for progress view
diff --git a/sw/source/uibase/lingu/hyp.cxx b/sw/source/uibase/lingu/hyp.cxx
index 3b2385f80e35..8f96c7fa9481 100644
--- a/sw/source/uibase/lingu/hyp.cxx
+++ b/sw/source/uibase/lingu/hyp.cxx
@@ -118,7 +118,7 @@ SwHyphWrapper::~SwHyphWrapper()
 {
     if( nPageCount )
         ::EndProgress( pView->GetDocShell() );
-    if( bInfoBox )
+    if( bInfoBox && !Application::IsHeadlessModeEnabled() )
         ScopedVclPtrInstance<InfoBox>(&pView->GetEditWin(), SW_RESSTR(STR_HYP_OK))->Execute();
 }