From a780e25d38af03f4c3242a330a56ca7c62b3d217 Mon Sep 17 00:00:00 2001
From: Abdelrazak Younes <younes@lyx.org>
Date: Thu, 8 Feb 2007 08:44:45 +0000
Subject: [PATCH] Preliminary safeguard code to fix bug 3189.

* DocIterator::prevInset(): return 0 if the mathed cell() is empty.

* LCursor::info(): use prevInset() only if different from zero.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@17104 a592a061-630c-0410-9148-cb99ea01b6c8
---
 src/cursor.C      | 17 +++++++++++++++--
 src/dociterator.C | 16 ++++++++++++++--
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/src/cursor.C b/src/cursor.C
index ad749e3aaa..05fc44099a 100644
--- a/src/cursor.C
+++ b/src/cursor.C
@@ -510,6 +510,15 @@ void LCursor::setSelection(DocIterator const & where, int n)
 }
 
 
+void LCursor::setSelection(DocIterator const & from,
+		DocIterator const & to)
+{
+	setCursor(to);
+	selection() = true;
+	anchor_ = from;
+}
+
+
 void LCursor::clearSelection()
 {
 	selection() = false;
@@ -543,8 +552,12 @@ void LCursor::info(odocstream & os) const
 		operator[](i).inset().infoize(os);
 		os << "  ";
 	}
-	if (pos() != 0)
-		prevInset()->infoize2(os);
+	if (pos() != 0) {
+		InsetBase const * inset = prevInset();
+		// prevInset() can return 0 in certain case.
+		if (inset)
+			prevInset()->infoize2(os);
+	}
 	// overwite old message
 	os << "                    ";
 }
diff --git a/src/dociterator.C b/src/dociterator.C
index bb72fb6c2d..ad96095022 100644
--- a/src/dociterator.C
+++ b/src/dociterator.C
@@ -78,7 +78,13 @@ InsetBase * DocIterator::prevInset()
 	if (pos() == 0)
 		return 0;
 	if (inMathed())
-		return prevAtom().nucleus();
+		if (cell().empty())
+			// FIXME: this should not happen but it does.
+			// See bug 3189
+			// http://bugzilla.lyx.org/show_bug.cgi?id=3189
+			return 0;
+		else
+			return prevAtom().nucleus();
 	return paragraph().isInset(pos() - 1) ? paragraph().getInset(pos() - 1) : 0;
 }
 
@@ -89,7 +95,13 @@ InsetBase const * DocIterator::prevInset() const
 	if (pos() == 0)
 		return 0;
 	if (inMathed())
-		return prevAtom().nucleus();
+		if (cell().empty())
+			// FIXME: this should not happen but it does.
+			// See bug 3189
+			// http://bugzilla.lyx.org/show_bug.cgi?id=3189
+			return 0;
+		else
+			return prevAtom().nucleus();
 	return paragraph().isInset(pos() - 1) ? paragraph().getInset(pos() - 1) : 0;
 }
 
-- 
2.39.5