[gtk+/parser: 64/80] cssprovider: Add recursion checks for @import

[Benjamin Otte <otte src gnome org>]

commit 1245ef76f8f6594c70da8c1e08b5d5d88c85d49b
Author: Benjamin Otte <otte redhat com>
Date:   Tue Apr 12 02:50:25 2011 +0200

    cssprovider: Add recursion checks for @import
    
    This is pretty important, because otherwise recursions cause crashes.
    And if you accidentally change your theme to one that crashes on load,
    all your gonna SEGV and then on reboot, gdm tries to load the theme...

 gtk/gtkcssprovider.c |   42 ++++++++++++++++++++++++++++++++++++------
 1 files changed, 36 insertions(+), 6 deletions(-)
---
diff --git a/gtk/gtkcssprovider.c b/gtk/gtkcssprovider.c
index 3a89715..ac8cb1b 100644
--- a/gtk/gtkcssprovider.c
+++ b/gtk/gtkcssprovider.c
@@ -1238,6 +1238,23 @@ gtk_css_scanner_get_base_url (GScanner *scanner)
   return priv->base;
 }
 
+static gboolean
+gtk_css_scanner_would_recurse (GScanner *scanner,
+                               GFile    *file)
+{
+  while (scanner)
+    {
+      GtkCssScannerPrivate *priv = scanner->user_data;
+
+      if (priv->file && g_file_equal (priv->file, file))
+        return TRUE;
+
+      scanner = priv->parent;
+    }
+
+  return FALSE;
+}
+
 static void
 gtk_css_provider_init (GtkCssProvider *css_provider)
 {
@@ -2282,12 +2299,25 @@ parse_rule (GtkCssProvider  *css_provider,
               return ';';
             }
 
-          /* FIXME: Avoid recursive importing */
-          gtk_css_provider_load_internal (css_provider,
-                                          scanner,
-                                          actual,
-                                          NULL, 0,
-                                          NULL);
+          if (gtk_css_scanner_would_recurse (scanner, actual))
+            {
+              char *path = g_file_get_path (actual);
+              gtk_css_provider_error (css_provider,
+                                      scanner,
+                                      GTK_CSS_PROVIDER_ERROR,
+                                      GTK_CSS_PROVIDER_ERROR_IMPORT,
+                                      "Loading '%s' would recurse",
+                                      path);
+              g_free (path);
+            }
+          else
+            {
+              gtk_css_provider_load_internal (css_provider,
+                                              scanner,
+                                              actual,
+                                              NULL, 0,
+                                              NULL);
+            }
 
           g_object_unref (actual);