[gnumeric] Fix crash in cell_calc_span. [#624274]

[Jean Bréfort <jbrefort src gnome org>]

commit 3c84c09ca75b2af2cfe9a7b8570ee218da7e9ba5
Author: Jean Brefort <jean brefort normalesup org>
Date:   Tue Jul 13 21:39:42 2010 +0200

    Fix crash in cell_calc_span. [#624274]

 ChangeLog      |    4 ++++
 NEWS           |    1 +
 src/cellspan.c |    3 ++-
 3 files changed, 7 insertions(+), 1 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 0bc5f78..700293f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2010-07-13  Jean Brefort  <jean brefort normalesup org>
 
+	* src/cellspan.c (cell_calc_span): fixed crash introduced earlier. [#624274]
+
+2010-07-13  Jean Brefort  <jean brefort normalesup org>
+
 	* src/graph.c (gnm_go_data_vector_load_len): fixed a regression. [#624263]
 
 2010-07-13  Jean Brefort  <jean brefort normalesup org>
diff --git a/NEWS b/NEWS
index 8049757..9313104 100644
--- a/NEWS
+++ b/NEWS
@@ -33,6 +33,7 @@ Jean:
 	* Fix strong/weak cursor display. [#623241]
 	* Fix regression in ms_excel_chart_read. [#623960]
 	* Fix a regression in chart series evaluation. [#624263]
+	* Fix crash in cell_calc_span. [#624274]
 	* Install a self-consistent headers list.
 
 Morten:
diff --git a/src/cellspan.c b/src/cellspan.c
index 611af76..256ea5f 100644
--- a/src/cellspan.c
+++ b/src/cellspan.c
@@ -235,7 +235,8 @@ cell_calc_span (GnmCell const *cell, int *col1, int *col2)
 	indented_w = cell_width_pixel = gnm_cell_rendered_width (cell);
 	if (h_align == HALIGN_LEFT || h_align == HALIGN_RIGHT) {
 		GnmRenderedValue *rv = gnm_cell_get_rendered_value (cell);
-		PangoDirection dir = pango_find_base_dir (pango_layout_get_text (rv->layout), -1);
+		char const *text = pango_layout_get_text (rv->layout);
+		PangoDirection dir = (text && *text)? pango_find_base_dir (text, -1): PANGO_DIRECTION_LTR;
 		if (gnm_style_get_align_h (style) == HALIGN_GENERAL && dir == PANGO_DIRECTION_RTL)
 			h_align = HALIGN_RIGHT;
 		indented_w += gnm_cell_rendered_offset (cell);