[glib] gvaluetransform: Fix an infinite loop with GFlagsValue sets with the 0 value

[Rui Matos <rtcm src gnome org>]

commit 9ff09f34cf0bc5fbc951490923880d82d94862d1
Author: Rui Matos <tiagomatos gmail com>
Date:   Tue Feb 21 16:42:43 2012 +0100

    gvaluetransform: Fix an infinite loop with GFlagsValue sets with the 0 value
    
    Transforming a GValue holding flags from a GFlagsValue set that includes the 0
    value (no flag bits set) into a string would loop until exhausting all the
    available memory.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=670557

 gobject/gvaluetransform.c |    2 +-
 gobject/tests/enums.c     |   16 ++++++++++++++--
 2 files changed, 15 insertions(+), 3 deletions(-)
---
diff --git a/gobject/gvaluetransform.c b/gobject/gvaluetransform.c
index 2352be5..a785817 100644
--- a/gobject/gvaluetransform.c
+++ b/gobject/gvaluetransform.c
@@ -216,7 +216,7 @@ value_transform_flags_string (const GValue *src_value,
           g_string_append (gstring, flags_value->value_name);
           flags_value = g_flags_get_first_value (class, v_flags);
         }
-      while (flags_value);
+      while (flags_value && v_flags);
       
       if (v_flags)
         dest_value->data[0].v_pointer = g_strdup_printf ("%s | %u",
diff --git a/gobject/tests/enums.c b/gobject/tests/enums.c
index e744bed..72df8a8 100644
--- a/gobject/tests/enums.c
+++ b/gobject/tests/enums.c
@@ -52,12 +52,22 @@ test_enum_basic (void)
 
 static const GFlagsValue my_flag_values[] =
 {
+  { 0, "no flags", "none" },
   { 1, "the first flag", "one" },
   { 2, "the second flag", "two" },
   { 8, "the third flag", "three" },
   { 0, NULL, NULL }
 };
 
+static void
+test_flags_transform_to_string (const GValue *value)
+{
+  GValue tmp = G_VALUE_INIT;
+
+  g_value_init (&tmp, G_TYPE_STRING);
+  g_value_transform (value, &tmp);
+  g_value_unset (&tmp);
+}
 
 static void
 test_flags_basic (void)
@@ -74,12 +84,11 @@ test_flags_basic (void)
 
   g_value_set_flags (&value, 2|8);
   g_assert_cmpint (g_value_get_flags (&value), ==, 2|8);
-  g_value_unset (&value);
 
   class = g_type_class_ref (type);
 
   g_assert_cmpint (class->mask, ==, 1|2|8);
-  g_assert_cmpint (class->n_values, ==, 3);
+  g_assert_cmpint (class->n_values, ==, 4);
 
   val = g_flags_get_first_value (class, 2|8);
   g_assert (val != NULL);
@@ -98,6 +107,9 @@ test_flags_basic (void)
   g_assert_cmpint (val->value, ==, 1);
   val = g_flags_get_value_by_nick (class, "purple");
   g_assert (val == NULL);
+
+  test_flags_transform_to_string (&value);
+  g_value_unset (&value);
 }
 
 int