gbookmarkfile: Fix error reporting with unexpected nesting of elements

The parser state machine for bookmark files did not handle unexpected
nesting of elements, such as a <bookmark> element inside a <title>
element — it would print a critical warning rather than returning a
GError.

Fix that, and add various unit tests for it. The set of tests includes
various other general markup tests as provided by Jussi Judin.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

https://gitlab.gnome.org/GNOME/glib/issues/1035

glib/gbookmarkfile.c

@@ -210,7 +210,7 @@ struct _GBookmarkFile
 };
 
 /* parser state machine */
-enum
+typedef enum
 {
   STATE_STARTED        = 0,
   
@@ -228,7 +228,7 @@ enum
   STATE_ICON,
   
   STATE_FINISHED
-};
+} ParserState;
 
 static void          g_bookmark_file_init        (GBookmarkFile  *bookmark);
 static void          g_bookmark_file_clear       (GBookmarkFile  *bookmark);
@@ -681,7 +681,7 @@ g_bookmark_file_clear (GBookmarkFile *bookmark)
 
 struct _ParseData
 {
-  gint state;
+  ParserState state;
   
   GHashTable *namespaces;
   
@@ -1083,6 +1083,43 @@ is_element_full (ParseData   *parse_data,
 #define IS_ELEMENT(p,s,e)	(is_element_full ((p), (s), NULL, (e), '\0'))
 #define IS_ELEMENT_NS(p,s,n,e)	(is_element_full ((p), (s), (n), (e), '|'))
 
+static const gchar *
+parser_state_to_element_name (ParserState state)
+{
+  switch (state)
+    {
+    case STATE_STARTED:
+    case STATE_FINISHED:
+      return "(top-level)";
+    case STATE_ROOT:
+      return XBEL_ROOT_ELEMENT;
+    case STATE_BOOKMARK:
+      return XBEL_BOOKMARK_ELEMENT;
+    case STATE_TITLE:
+      return XBEL_TITLE_ELEMENT;
+    case STATE_DESC:
+      return XBEL_DESC_ELEMENT;
+    case STATE_INFO:
+      return XBEL_INFO_ELEMENT;
+    case STATE_METADATA:
+      return XBEL_METADATA_ELEMENT;
+    case STATE_APPLICATIONS:
+      return BOOKMARK_APPLICATIONS_ELEMENT;
+    case STATE_APPLICATION:
+      return BOOKMARK_APPLICATION_ELEMENT;
+    case STATE_GROUPS:
+      return BOOKMARK_GROUPS_ELEMENT;
+    case STATE_GROUP:
+      return BOOKMARK_GROUP_ELEMENT;
+    case STATE_MIME:
+      return MIME_TYPE_ELEMENT;
+    case STATE_ICON:
+      return BOOKMARK_ICON_ELEMENT;
+    default:
+      g_assert_not_reached ();
+    }
+}
+
 static void
 start_element_raw_cb (GMarkupParseContext *context,
                       const gchar         *element_name,
@@ -1263,8 +1300,23 @@ start_element_raw_cb (GMarkupParseContext *context,
         	     element_name,
         	     BOOKMARK_GROUP_ELEMENT);
       break;
+
+    case STATE_TITLE:
+    case STATE_DESC:
+    case STATE_APPLICATION:
+    case STATE_GROUP:
+    case STATE_MIME:
+    case STATE_ICON:
+    case STATE_FINISHED:
+      g_set_error (error, G_MARKUP_ERROR,
+                   G_MARKUP_ERROR_INVALID_CONTENT,
+                   _("Unexpected tag “%s” inside “%s”"),
+                   element_name,
+                   parser_state_to_element_name (parse_data->state));
+      break;
+
     default:
-      g_warn_if_reached ();
+      g_assert_not_reached ();
       break;
     }
 }

glib/tests/Makefile.am

@@ -143,6 +143,27 @@ dist_test_data += \
 	bookmarks/fail-15.xbel \
 	bookmarks/fail-16.xbel \
 	bookmarks/fail-17.xbel \
+	bookmarks/fail-18.xbel \
+	bookmarks/fail-19.xbel \
+	bookmarks/fail-20.xbel \
+	bookmarks/fail-21.xbel \
+	bookmarks/fail-22.xbel \
+	bookmarks/fail-23.xbel \
+	bookmarks/fail-24.xbel \
+	bookmarks/fail-25.xbel \
+	bookmarks/fail-26.xbel \
+	bookmarks/fail-27.xbel \
+	bookmarks/fail-28.xbel \
+	bookmarks/fail-29.xbel \
+	bookmarks/fail-30.xbel \
+	bookmarks/fail-31.xbel \
+	bookmarks/fail-32.xbel \
+	bookmarks/fail-33.xbel \
+	bookmarks/fail-34.xbel \
+	bookmarks/fail-35.xbel \
+	bookmarks/fail-36.xbel \
+	bookmarks/fail-37.xbel \
+	bookmarks/fail-38.xbel \
 	bookmarks/valid-01.xbel \
 	bookmarks/valid-02.xbel \
 	bookmarks/valid-03.xbel \

glib/tests/bookmarks/fail-18.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE><xbel version="1.0"xmlns:bookmark="http://www.freedesktop.org/standards/desktop-bookmarks"><title><bookmark:application c=""/><bookmark:application name=""exec=""/

glib/tests/bookmarks/fail-19.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE><xbel version="1.0"xmlns:mime="http://www.freedesktop.org/standards/shared-mime-info"xmlns:bookmark="http://www.freedesktop.org/standards/desktop-bookmarks"><title><mime:mime-type></mime:mime-type><bookmark:applications><bookmark:application name=""exec=""/

glib/tests/bookmarks/fail-20.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE<<><>>></

glib/tests/bookmarks/fail-21.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE><xbel version="1.0"xmlns:bookmark="http://www.freedesktop.org/standards/desktop-bookmarks"><title><bookmark:application e=""/><bookmark:application name=""exec=""/

glib/tests/bookmarks/fail-22.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE><xbel version="1.0"xmlns:bookmark="http://www.freedesktop.org/standards/desktop-bookmarks"><title><bookmark:application e=""/><bookmark:application name=""exec="">

glib/tests/bookmarks/fail-23.xbel

@@ -0,0 +1 @@
+</

glib/tests/bookmarks/fail-24.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE><xbel version="1.0"xmlns:bookmark="http://www.freedesktop.org/standards/desktop-bookmarks"><title><bookmark:application n=""/><bookmark:application name=""exec="">

glib/tests/bookmarks/fail-25.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE><xbel version="1.0"xmlns:bookmark="http://www.freedesktop.org/standards/desktop-bookmarks"><title><bookmark:applications></bookmark:applications><bookmark:groups><bookmark:group><

glib/tests/bookmarks/fail-26.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE<><>></

glib/tests/bookmarks/fail-27.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE><xbel version="1.0"xmlns:bookmark="http://www.freedesktop.org/standards/desktop-bookmarks"f=""><title><bookmark:application e=""/><bookmark:application name=""exec=""/

glib/tests/bookmarks/fail-28.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE<><><>></

glib/tests/bookmarks/fail-29.xbel

@@ -0,0 +1 @@
+<?></

glib/tests/bookmarks/fail-30.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE<><<>><>></

glib/tests/bookmarks/fail-31.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE<><<>>></

glib/tests/bookmarks/fail-32.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE></

glib/tests/bookmarks/fail-33.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE<><><><>></

glib/tests/bookmarks/fail-34.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE<<>>></

glib/tests/bookmarks/fail-35.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE><xbel version="1.0"xmlns:mime="http://www.freedesktop.org/standards/shared-mime-info"m=""><title><mime:mime-type></mime:mime-type><mime:mime-type>

glib/tests/bookmarks/fail-36.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE><xbel version="1.0"xmlns:mime="http://www.freedesktop.org/standards/shared-mime-info"xmlns:bookmark="http://www.freedesktop.org/standards/desktop-bookmarks"><title><mime:mime-type></mime:mime-type><bookmark:applications><application name=""exec="">

glib/tests/bookmarks/fail-37.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE><xbel version="1.0"xmlns:mime="http://www.freedesktop.org/standards/shared-mime-info"xmlns:bookmark="http://www.freedesktop.org/standards/desktop-bookmarks"><title><mime:mime-type></mime:mime-type><bookmark:applications><bookmark:application name=""exec="">

glib/tests/bookmarks/fail-38.xbel

@@ -0,0 +1 @@
+<?><!DOCTYPE><xbel x=""/><o xmlns:bookmark="http://www.freedesktop.org/standards/desktop-bookmarks"><bookmark:application e=""/><bookmark:application name=""exec=""/