glib/gobject/tests/binding.c

#include <stdlib.h>
#include <gstdio.h>
#include <glib-object.h>

typedef struct _BindingSource
{
  GObject parent_instance;

  gint foo;
  gdouble value;
} BindingSource;

typedef struct _BindingSourceClass
{
  GObjectClass parent_class;
} BindingSourceClass;

enum
{
  PROP_SOURCE_0,

  PROP_SOURCE_FOO,

  PROP_SOURCE_VALUE
};

G_DEFINE_TYPE (BindingSource, binding_source, G_TYPE_OBJECT);

static void
binding_source_set_property (GObject      *gobject,
                             guint         prop_id,
                             const GValue *value,
                             GParamSpec   *pspec)
{
  BindingSource *source = (BindingSource *) gobject;

  switch (prop_id)
    {
    case PROP_SOURCE_FOO:
      source->foo = g_value_get_int (value);
      break;

    case PROP_SOURCE_VALUE:
      source->value = g_value_get_double (value);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
    }
}

static void
binding_source_get_property (GObject    *gobject,
                             guint       prop_id,
                             GValue     *value,
                             GParamSpec *pspec)
{
  BindingSource *source = (BindingSource *) gobject;

  switch (prop_id)
    {
    case PROP_SOURCE_FOO:
      g_value_set_int (value, source->foo);
      break;

    case PROP_SOURCE_VALUE:
      g_value_set_double (value, source->value);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
    }
}

static void
binding_source_class_init (BindingSourceClass *klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

  gobject_class->set_property = binding_source_set_property;
  gobject_class->get_property = binding_source_get_property;

  g_object_class_install_property (gobject_class, PROP_SOURCE_FOO,
                                   g_param_spec_int ("foo", "Foo", "Foo",
                                                     -1, 100,
                                                     0,
                                                     G_PARAM_READWRITE));
  g_object_class_install_property (gobject_class, PROP_SOURCE_VALUE,
                                   g_param_spec_double ("value", "Value", "Value",
                                                        -100.0, 200.0,
                                                        0.0,
                                                        G_PARAM_READWRITE));
}

static void
binding_source_init (BindingSource *self)
{
}

typedef struct _BindingTarget
{
  GObject parent_instance;

  gint bar;
  gdouble value;
} BindingTarget;

typedef struct _BindingTargetClass
{
  GObjectClass parent_class;
} BindingTargetClass;

enum
{
  PROP_TARGET_0,

  PROP_TARGET_BAR,

  PROP_TARGET_VALUE
};

G_DEFINE_TYPE (BindingTarget, binding_target, G_TYPE_OBJECT);

static void
binding_target_set_property (GObject      *gobject,
                             guint         prop_id,
                             const GValue *value,
                             GParamSpec   *pspec)
{
  BindingTarget *target = (BindingTarget *) gobject;

  switch (prop_id)
    {
    case PROP_TARGET_BAR:
      target->bar = g_value_get_int (value);
      break;

    case PROP_TARGET_VALUE:
      target->value = g_value_get_double (value);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
    }
}

static void
binding_target_get_property (GObject    *gobject,
                             guint       prop_id,
                             GValue     *value,
                             GParamSpec *pspec)
{
  BindingTarget *target = (BindingTarget *) gobject;

  switch (prop_id)
    {
    case PROP_TARGET_BAR:
      g_value_set_int (value, target->bar);
      break;

    case PROP_TARGET_VALUE:
      g_value_set_double (value, target->value);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
    }
}

static void
binding_target_class_init (BindingTargetClass *klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

  gobject_class->set_property = binding_target_set_property;
  gobject_class->get_property = binding_target_get_property;

  g_object_class_install_property (gobject_class, PROP_TARGET_BAR,
                                   g_param_spec_int ("bar", "Bar", "Bar",
                                                     -1, 100,
                                                     0,
                                                     G_PARAM_READWRITE));
  g_object_class_install_property (gobject_class, PROP_SOURCE_VALUE,
                                   g_param_spec_double ("value", "Value", "Value",
                                                        -100.0, 200.0,
                                                        0.0,
                                                        G_PARAM_READWRITE));
}

static void
binding_target_init (BindingTarget *self)
{
}

static gboolean
celsius_to_fahrenheit (GBinding     *binding,
                       const GValue *source_value,
                       GValue       *target_value,
                       gpointer      user_data G_GNUC_UNUSED)
{
  gdouble celsius, fahrenheit;

  g_assert (G_VALUE_HOLDS (source_value, G_TYPE_DOUBLE));
  g_assert (G_VALUE_HOLDS (target_value, G_TYPE_DOUBLE));

  celsius = g_value_get_double (source_value);
  fahrenheit = (9 * celsius / 5) + 32.0;

  if (g_test_verbose ())
    g_print ("Converting %.2fC to %.2fF\n", celsius, fahrenheit);

  g_value_set_double (target_value, fahrenheit);

  return TRUE;
}

static gboolean
fahrenheit_to_celsius (GBinding     *binding,
                       const GValue *source_value,
                       GValue       *target_value,
                       gpointer      user_data G_GNUC_UNUSED)
{
  gdouble celsius, fahrenheit;

  g_assert (G_VALUE_HOLDS (source_value, G_TYPE_DOUBLE));
  g_assert (G_VALUE_HOLDS (target_value, G_TYPE_DOUBLE));

  fahrenheit = g_value_get_double (source_value);
  celsius = 5 * (fahrenheit - 32.0) / 9;

  if (g_test_verbose ())
    g_print ("Converting %.2fF to %.2fC\n", fahrenheit, celsius);

  g_value_set_double (target_value, celsius);

  return TRUE;
}

static void
binding_default (void)
{
  BindingSource *source = g_object_new (binding_source_get_type (), NULL);
  BindingTarget *target = g_object_new (binding_target_get_type (), NULL);
  GBinding *binding;

  binding = g_object_bind_property (source, "foo",
                                    target, "bar",
                                    G_BINDING_DEFAULT);

  g_object_set (source, "foo", 42, NULL);
  g_assert_cmpint (source->foo, ==, target->bar);

  g_object_set (target, "bar", 47, NULL);
  g_assert_cmpint (source->foo, !=, target->bar);

  g_object_unref (binding);

  g_object_set (source, "foo", 0, NULL);
  g_assert_cmpint (source->foo, !=, target->bar);

  g_object_unref (source);
  g_object_unref (target);
}

static void
binding_bidirectional (void)
{
  BindingSource *source = g_object_new (binding_source_get_type (), NULL);
  BindingTarget *target = g_object_new (binding_target_get_type (), NULL);
  GBinding *binding;

  binding = g_object_bind_property (source, "foo",
                                    target, "bar",
                                    G_BINDING_BIDIRECTIONAL);

  g_object_set (source, "foo", 42, NULL);
  g_assert_cmpint (source->foo, ==, target->bar);

  g_object_set (target, "bar", 47, NULL);
  g_assert_cmpint (source->foo, ==, target->bar);

  g_object_unref (binding);

  g_object_set (source, "foo", 0, NULL);
  g_assert_cmpint (source->foo, !=, target->bar);

  g_object_unref (source);
  g_object_unref (target);
}

static void
binding_transform (void)
{
  BindingSource *source = g_object_new (binding_source_get_type (), NULL);
  BindingTarget *target = g_object_new (binding_target_get_type (), NULL);
  GBinding *binding;

  binding = g_object_bind_property_full (source, "value",
                                         target, "value",
                                         G_BINDING_BIDIRECTIONAL,
                                         celsius_to_fahrenheit,
                                         fahrenheit_to_celsius,
                                         NULL, NULL);

  g_object_set (source, "value", 24.0, NULL);
  g_assert_cmpfloat (target->value, ==, ((9 * 24.0 / 5) + 32.0));

  g_object_set (target, "value", 69.0, NULL);
  g_assert_cmpfloat (source->value, ==, (5 * (69.0 - 32.0) / 9));

  g_object_unref (source);
  g_object_unref (target);
}

static void
binding_chain (void)
{
  BindingSource *a = g_object_new (binding_source_get_type (), NULL);
  BindingSource *b = g_object_new (binding_source_get_type (), NULL);
  BindingSource *c = g_object_new (binding_source_get_type (), NULL);
  GBinding *binding_1, *binding_2;

  /* A -> B, B -> C */
  binding_1 = g_object_bind_property (a, "foo", b, "foo", G_BINDING_BIDIRECTIONAL);
  binding_2 = g_object_bind_property (b, "foo", c, "foo", G_BINDING_BIDIRECTIONAL);

  /* verify the chain */
  g_object_set (a, "foo", 42, NULL);
  g_assert_cmpint (a->foo, ==, b->foo);
  g_assert_cmpint (b->foo, ==, c->foo);

  /* unbind A -> B and B -> C */
  g_object_unref (binding_1);
  g_object_unref (binding_2);

  /* bind A -> C directly */
  binding_2 = g_object_bind_property (a, "foo", c, "foo", G_BINDING_BIDIRECTIONAL);

  /* verify the chain is broken */
  g_object_set (a, "foo", 47, NULL);
  g_assert_cmpint (a->foo, !=, b->foo);
  g_assert_cmpint (a->foo, ==, c->foo);

  g_object_unref (a);
  g_object_unref (b);
  g_object_unref (c);
}

int
main (int argc, char *argv[])
{
  g_type_init ();
  g_test_init (&argc, &argv, NULL);

  g_test_add_func ("/binding/default", binding_default);
  g_test_add_func ("/binding/bidirectional", binding_bidirectional);
  g_test_add_func ("/binding/transform", binding_transform);
  g_test_add_func ("/binding/chain", binding_chain);

  return g_test_run ();
}