sw/source/core/inc/txtfrm.hxx |2 ++
sw/source/core/text/frmform.cxx |9 -
sw/source/core/text/txtfrm.cxx |8
3 files changed, 14 insertions(+), 5 deletions(-)
New commits:
commit d83f066a8f70e260b388275fe596b37df0ad1eeb
Author: Michael Stahl
AuthorDate: Fri Dec 20 17:28:55 2019 +0100
Commit: Michael Stahl
CommitDate: Mon Dec 23 11:26:49 2019 +0100
sw: fix widow loop with as-char flys in text formatting
The document has a paragraph with 4 as-character anchored flys depicting
Zirbenholz; due to their size and an additional fly that is anchored at
the paragraph, there are 3 lines that do not fit onto a single page.
This situation causes a loop that proceeds like this:
text frame 80 is the follow of text frame 21.
when formatting 80:
the 1 line violates the widow rule (>=2) and PREP_WIDOWS is sent to
21, invalidating its FrameAreaSize
80 validates its FrameAreaSize
when formatting 21:
PREP_WIDOWS_ORPHANS sent to 21
CalcPreps() sees IsPrepWidows() and sets a huge height and calls
SetWidow(true)
SwTextFrame::WouldFit() sees IsWidow() true and resets it false
SwTextFrame::WouldFit() sees IsWidow() false and a huge but
insufficiently huge height
21 validates its FrameAreaSize
CalcPreps() sees IsPrepAdjust()
FindBreak() calls TruncLines() and because of as-char fly
invalidates FrameAreaSize of 80
The loop is most easily reproduced by printing via the API; it's
possible to get a loop when loading the document in the UI, but
typically the UI remains responsive even though the layout never
finishes.
As it happens, before commit ee299664940139f6f9543592ece3b3c0210b59f4
"SalInstance::DoYield: Don't drop SolarMutex when accessing user event
queue" the loop on printing via API was broken by releasing SolarMutex;
the result, however, was incorrect, with the last line of Zirbenholz
that should be on the second page missing in the PDF.
This loop is presumably a regression from commit
f2e3655255db4032738849cd4b77ce67a6e2c984 "Avoid
-fsanitize=signed-integer-overflow", which changed a magic number in
SwTextFrame::CalcPreps(), but didn't adapt the poorly documented
corresponding magic numbers in SwTextFrame::WouldFit(); in LO 5.1.6.2
the CPU is idle after loading the document.
Change-Id: Ib6563c21edb68945c14a61b51ba34f0ee3f2544a
Reviewed-on: https://gerrit.libreoffice.org/85623
Tested-by: Jenkins
Reviewed-by: Michael Stahl
(cherry picked from commit 68a5afaaabd0c75bba3439cfdff90fb75d1cdd3f)
diff --git a/sw/source/core/inc/txtfrm.hxx b/sw/source/core/inc/txtfrm.hxx
index 98a18f7ed8ad..ce5ec49232ed 100644
--- a/sw/source/core/inc/txtfrm.hxx
+++ b/sw/source/core/inc/txtfrm.hxx
@@ -964,6 +964,8 @@ public:
};
+const SwTwips WIDOW_MAGIC = (SAL_MAX_INT32 - 1)/2;
+
} // namespace sw
#endif
diff --git a/sw/source/core/text/frmform.cxx b/sw/source/core/text/frmform.cxx
index 959daa4ea9a1..d5a402ebe4c6 100644
--- a/sw/source/core/text/frmform.cxx
+++ b/sw/source/core/text/frmform.cxx
@@ -849,7 +849,7 @@ bool SwTextFrame::CalcPreps()
// the range of 'long', while the value (SAL_MAX_INT32 -
1)/2 (which matches the
// old value on platforms where 'long' is 'sal_Int32') is
empirically shown to
// be large enough in practice even on platforms where
'long' is 'sal_Int64':
-SwTwips nTmp = (SAL_MAX_INT32 - 1)/2 -
(getFrameArea().Top()+1);
+SwTwips const nTmp = sw::WIDOW_MAGIC -
(getFrameArea().Top()+1);
SwTwips nDiff = nTmp - getFrameArea().Height();
{
diff --git a/sw/source/core/text/txtfrm.cxx b/sw/source/core/text/txtfrm.cxx
index 62b281ae6974..377dd17c5103 100644
--- a/sw/source/core/text/txtfrm.cxx
+++ b/sw/source/core/text/txtfrm.cxx
@@ -2759,9 +2759,9 @@ bool SwTextFrame::WouldFit( SwTwips &rMaxHeight, bool
&bSplit, bool bTst )
// Because the Orphan flag only exists for a short moment, we also check
// whether the Framesize is set to very huge by CalcPreps, in order to
// force a MoveFwd
-if( IsWidow() || ( aRectFnSet.IsVert() ?
- ( 0 == getFrameArea().Left() ) :
- ( LONG_MAX - 2 < getFrameArea().Bottom() ) ) )
+if (IsWidow() || (aRectFnSet.IsVert()
+? (0 == getFrameArea().Left())
+: (sw::WIDOW_MAGIC - 2 < getFrameArea().Bottom(
{
SetWidow(false);
if ( GetFollow() )
@@ -2770,7 +2770,7 @@ bool SwTextFrame::WouldFit( SwTwips &rMaxHeight, bool
&bSplit, bool bTst )
// whether there's a Follow with a real height at all.
// Else (e.g. for newly created SctFrames) we ignore the IsWidow()
and
