[glib] Allow passing unset GValues to g_value_unset()

[Dan Winship <danw src gnome org>]

commit 4b2d92a864f1505f1b08eb639d74293fa32681da
Author: Dan Winship <danw gnome org>
Date:   Fri Oct 2 10:06:22 2015 -0400

    Allow passing unset GValues to g_value_unset()
    
    This makes it more useful as an autocleanup func.
    
    Also, add a minimal test of g_value_init/g_value_reset/g_value_unset.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=755766

 gobject/gvalue.c           |   11 +++--
 gobject/tests/.gitignore   |    2 +-
 gobject/tests/Makefile.am  |    2 +-
 gobject/tests/value.c      |   95 ++++++++++++++++++++++++++++++++++++++++++++
 gobject/tests/valuearray.c |   64 -----------------------------
 5 files changed, 104 insertions(+), 70 deletions(-)
---
diff --git a/gobject/gvalue.c b/gobject/gvalue.c
index 5277b77..a3709b4 100644
--- a/gobject/gvalue.c
+++ b/gobject/gvalue.c
@@ -254,16 +254,19 @@ g_value_reset (GValue *value)
  * g_value_unset:
  * @value: An initialized #GValue structure.
  *
- * Clears the current value in @value and "unsets" the type,
- * this releases all resources associated with this GValue.
- * An unset value is the same as an uninitialized (zero-filled)
- * #GValue structure.
+ * Clears the current value in @value (if any) and "unsets" the type,
+ * this releases all resources associated with this GValue. An unset
+ * value is the same as an uninitialized (zero-filled) #GValue
+ * structure.
  */
 void
 g_value_unset (GValue *value)
 {
   GTypeValueTable *value_table;
   
+  if (value->g_type == 0)
+    return;
+
   g_return_if_fail (G_IS_VALUE (value));
 
   value_table = g_type_value_table_peek (G_VALUE_TYPE (value));
diff --git a/gobject/tests/.gitignore b/gobject/tests/.gitignore
index a3f8db3..28bb982 100644
--- a/gobject/tests/.gitignore
+++ b/gobject/tests/.gitignore
@@ -12,6 +12,6 @@ reference
 signals
 threadtests
 type
-valuearray
+value
 private
 marshalers.[ch]
diff --git a/gobject/tests/Makefile.am b/gobject/tests/Makefile.am
index bfd962b..da36e19 100644
--- a/gobject/tests/Makefile.am
+++ b/gobject/tests/Makefile.am
@@ -17,7 +17,7 @@ test_programs = \
        binding                         \
        properties                      \
        reference                       \
-       valuearray                      \
+       value                           \
        type                            \
        private                         \
        closure                         \
diff --git a/gobject/tests/value.c b/gobject/tests/value.c
new file mode 100644
index 0000000..b5a1364
--- /dev/null
+++ b/gobject/tests/value.c
@@ -0,0 +1,95 @@
+#define GLIB_VERSION_MIN_REQUIRED       GLIB_VERSION_2_30
+#include <glib-object.h>
+
+static void
+test_value_basic (void)
+{
+  GValue value = G_VALUE_INIT;
+
+  g_assert_false (G_IS_VALUE (&value));
+  g_assert_false (G_VALUE_HOLDS_INT (&value));
+  g_value_unset (&value);
+  g_assert_false (G_IS_VALUE (&value));
+  g_assert_false (G_VALUE_HOLDS_INT (&value));
+
+  g_value_init (&value, G_TYPE_INT);
+  g_assert_true (G_IS_VALUE (&value));
+  g_assert_true (G_VALUE_HOLDS_INT (&value));
+  g_assert_false (G_VALUE_HOLDS_UINT (&value));
+  g_assert_cmpint (g_value_get_int (&value), ==, 0);
+
+  g_value_set_int (&value, 10);
+  g_assert_cmpint (g_value_get_int (&value), ==, 10);
+
+  g_value_reset (&value);
+  g_assert_true (G_IS_VALUE (&value));
+  g_assert_true (G_VALUE_HOLDS_INT (&value));
+  g_assert_cmpint (g_value_get_int (&value), ==, 0);
+
+  g_value_unset (&value);
+  g_assert_false (G_IS_VALUE (&value));
+  g_assert_false (G_VALUE_HOLDS_INT (&value));
+}
+
+static gint
+cmpint (gconstpointer a, gconstpointer b)
+{
+  const GValue *aa = a;
+  const GValue *bb = b;
+
+  return g_value_get_int (aa) - g_value_get_int (bb);
+}
+
+static void
+test_valuearray_basic (void)
+{
+  GValueArray *a;
+  GValueArray *a2;
+  GValue v = G_VALUE_INIT;
+  GValue *p;
+  gint i;
+
+  a = g_value_array_new (20);
+
+  g_value_init (&v, G_TYPE_INT);
+  for (i = 0; i < 100; i++)
+    {
+      g_value_set_int (&v, i);
+      g_value_array_append (a, &v);
+    }
+
+  g_assert_cmpint (a->n_values, ==, 100);
+  p = g_value_array_get_nth (a, 5);
+  g_assert_cmpint (g_value_get_int (p), ==, 5);
+
+  for (i = 20; i < 100; i+= 5)
+    g_value_array_remove (a, 100 - i);
+
+  for (i = 100; i < 150; i++)
+    {
+      g_value_set_int (&v, i);
+      g_value_array_prepend (a, &v);
+    }
+
+  g_value_array_sort (a, cmpint);
+  for (i = 0; i < a->n_values - 1; i++)
+    g_assert_cmpint (g_value_get_int (&a->values[i]), <=, g_value_get_int (&a->values[i+1]));
+
+  a2 = g_value_array_copy (a);
+  for (i = 0; i < a->n_values; i++)
+    g_assert_cmpint (g_value_get_int (&a->values[i]), ==, g_value_get_int (&a2->values[i]));
+
+  g_value_array_free (a);
+  g_value_array_free (a2);
+}
+
+int
+main (int argc, char *argv[])
+{
+  g_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/value/basic", test_value_basic);
+  g_test_add_func ("/value/array/basic", test_valuearray_basic);
+
+  return g_test_run ();
+}