[tracker] tracker-extract: Check string length before parsing XMP in the PDF extractor

[Carlos Garnacho <carlosg src gnome org>]

commit e877ac542caebe096db86ff6e370d3d1ee40a737
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Mar 14 01:07:53 2016 +0100

    tracker-extract: Check string length before parsing XMP in the PDF extractor
    
    tracker_xmp_new() may warn if we're given an empty string here.

 src/tracker-extract/tracker-extract-pdf.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/tracker-extract/tracker-extract-pdf.c b/src/tracker-extract/tracker-extract-pdf.c
index 6e2fef7..b750678 100644
--- a/src/tracker-extract/tracker-extract-pdf.c
+++ b/src/tracker-extract/tracker-extract-pdf.c
@@ -415,7 +415,7 @@ tracker_extract_get_metadata (TrackerExtractInfo *info)
 
        keywords = g_ptr_array_new ();
 
-       if (xml &&
+       if (xml && *xml &&
            (xd = tracker_xmp_new (xml, strlen (xml), uri)) != NULL) {
                /* The casts here are well understood and known */
                md.title = (gchar *) tracker_coalesce_strip (4, pd.title, xd->title, xd->title2, 
xd->pdf_title);