[gnumeric] Fix crash on corrupted files. [#706526]

[Andreas J. Guelzow <guelzow src gnome org>]

commit 87a2137bc3b046ed67ffe71c4323b767caa5dba9
Author: Andreas J Guelzow <aguelzow pyrshep ca>
Date:   Thu Aug 22 00:05:46 2013 -0600

    Fix crash on corrupted files. [#706526]
    
    2013-08-22  Andreas J. Guelzow <aguelzow pyrshep ca>
    
        * html_read.c (html_read_content): check for invalid UTF8

 NEWS                     |    3 +++
 plugins/html/ChangeLog   |    4 ++++
 plugins/html/html_read.c |    8 +++++---
 3 files changed, 12 insertions(+), 3 deletions(-)
---
diff --git a/NEWS b/NEWS
index 873086d..77d8c60 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,8 @@
 Gnumeric 1.12.6
 
+Andreas:
+       * Fix crash on corrupted files. [#706526]
+
 Morten:
        * Fix crash on corrupted files.  [#706413]  [#706417]
 
diff --git a/plugins/html/ChangeLog b/plugins/html/ChangeLog
index 1f8f418..c034cd4 100644
--- a/plugins/html/ChangeLog
+++ b/plugins/html/ChangeLog
@@ -1,3 +1,7 @@
+2013-08-22  Andreas J. Guelzow <aguelzow pyrshep ca>
+
+       * html_read.c (html_read_content): check for invalid UTF8
+
 2013-08-19  Morten Welinder <terra gnome org>
 
        * Release 1.12.5
diff --git a/plugins/html/html_read.c b/plugins/html/html_read.c
index 7e6f9f9..8e397a7 100644
--- a/plugins/html/html_read.c
+++ b/plugins/html/html_read.c
@@ -113,9 +113,11 @@ html_read_content (htmlNodePtr cur, GString *buf, GnmStyle *mstyle,
 
        for (ptr = cur->children; ptr != NULL ; ptr = ptr->next) {
                if (ptr->type == XML_TEXT_NODE) {
-                       html_append_text (buf, ptr->content);
-               }
-               else if (ptr->type == XML_ELEMENT_NODE) {
+                       if (g_utf8_validate (ptr->content, -1, NULL))
+                               html_append_text (buf, ptr->content);
+                       else
+                               g_string_append (buf, _("[Warning: Invalid text string has been removed.]"));
+               } else if (ptr->type == XML_ELEMENT_NODE) {
                        if (first) {
                                if (xmlStrEqual (ptr->name, CC2XML ("i"))
                                    || xmlStrEqual (ptr->name, CC2XML ("em")))