Bug#574579: glib reports wrong mimetype of svg file with long comments

[Darren Hoo]

retitle 574579 glib reports wrong mimetype of svg file with long comments
reassign  574579  shared-mime-info 0.71-1
tags  574579 +patch
thanks

After some digging, I found out that svg image with long comments at
the beginning can not show itself on  gtk widgets, is because glib reports
the wrong mimetype 'application/xml' instead of 'application/svg+xml',
so the pixbufloader can not find the correct svg_loader.

here's the testing code I used:

-----------------------------------------------------------
#include <gtk/gtk.h>
#include <glib/gprintf.h>
#include <errno.h>
int main(){
	FILE *f;
	guchar buffer [1024];
	gboolean uncertain;
	gchar *mime_type;
	guint size;
	const char *filename = "emacs23.svg";
	f = g_fopen (filename, "rb");
	if ( f == -1) {
			g_printf("open failed %s \n",g_strerror(errno));
			return 1;
	}
	size = fread (&buffer, 1, sizeof (buffer), f);
	if(size == 0){
			g_printf("No image data");
	}
	mime_type = g_content_type_guess (NULL, buffer, size, &uncertain);
	if (uncertain)
			mime_type = g_content_type_guess (filename, buffer, size, NULL);

	g_printf("%s \n", mime_type);
}
-----------------------------------------------------------

here it returns 'application/xml'  with uncertain  set to false.
with an offset of 256 in the svg section of freedesktop.org.xml  is
 too small, I think  increasing it to  1024 is reasonable.

to update the mime cache we have to run:
   update-mime-database  /usr/share/mime after changing freedesktop.org.xml

--------------------------------------------------------------

--- /tmp/freedesktop.org.xml	2010-03-21 14:39:14.730266924 +0800
+++ freedesktop.org.xml	2010-03-21 14:38:40.000000000 +0800
@@ -16246,7 +16246,7 @@
     <sub-class-of type="application/xml"/>
     <magic priority="80">
       <match value="&lt;!DOCTYPE svg" type="string" offset="0:256"/>
-      <match value="&lt;svg" type="string" offset="0:256"/>
+      <match value="&lt;svg" type="string" offset="0:1024"/>
     </magic>
     <glob pattern="*.svg"/>
   </mime-type>