[gexiv2] Disallow NULL for _set_comment

[Jens Georg <jensgeorg src gnome org>]

commit f7fac6fa90f54b6572185d019af19a512433b009
Author: Jens Georg <mail jensge org>
Date:   Sun Apr 30 10:13:28 2017 +0200

    Disallow NULL for _set_comment
    
    Fixes coverity issue CID 167853

 gexiv2/gexiv2-metadata.cpp |    3 ++-
 gexiv2/gexiv2-metadata.h   |    4 ++--
 2 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/gexiv2/gexiv2-metadata.cpp b/gexiv2/gexiv2-metadata.cpp
index 9f9b3cf..2b7424f 100644
--- a/gexiv2/gexiv2-metadata.cpp
+++ b/gexiv2/gexiv2-metadata.cpp
@@ -629,12 +629,13 @@ gchar* gexiv2_metadata_get_comment (GExiv2Metadata *self) {
 void gexiv2_metadata_set_comment (GExiv2Metadata *self, const gchar* comment) {
     g_return_if_fail(GEXIV2_IS_METADATA (self));
     g_return_if_fail(self->priv->image.get() != NULL);
+    g_return_if_fail(comment != NULL);
     
     Exiv2::ExifData& exif_data = self->priv->image->exifData();
     Exiv2::IptcData& iptc_data = self->priv->image->iptcData();
     Exiv2::XmpData& xmp_data = self->priv->image->xmpData();
     
-    gexiv2_metadata_set_comment_internal (self, (comment != NULL) ? comment : "");
+    gexiv2_metadata_set_comment_internal (self, comment);
     exif_data ["Exif.Image.ImageDescription"] = comment;
     exif_data ["Exif.Photo.UserComment"] = comment;
     exif_data ["Exif.Image.XPComment"] = comment;
diff --git a/gexiv2/gexiv2-metadata.h b/gexiv2/gexiv2-metadata.h
index 768319b..1225368 100644
--- a/gexiv2/gexiv2-metadata.h
+++ b/gexiv2/gexiv2-metadata.h
@@ -870,10 +870,10 @@ gchar*                    gexiv2_metadata_get_comment                     
(GExiv2Metadata *self);
 /**
  * gexiv2_metadata_set_comment:
  * @self: An instance of #GExiv2Metadata
- * @comment: Comment string to set
+ * @comment: Comment string to set. Must not be %NULL
  *
  * This is a composite setter that will set a number of fields to the supplied value.  See
- * #gexiv2_metadata_get_comment for more informtion.
+ * #gexiv2_metadata_get_comment for more information.
  */
 void                   gexiv2_metadata_set_comment                     (GExiv2Metadata *self, const gchar* 
comment);