gobject: Add GBinding

GBinding is a simple, opaque object that represents a binding between a
property on a GObject instance (source) and property on another GObject
instance (target).

https://bugzilla.gnome.org/show_bug.cgi?id=348080

3 files changed, 330 insertions, 1 deletions

diff --git a/gobject/tests/.gitignore b/gobject/tests/.gitignore
index bb48529e6..ca0d62868 100644
--- a/gobject/tests/.gitignore
+++ b/gobject/tests/.gitignore
@@ -1,2 +1,3 @@
+binding
 dynamictests
 threadtests
diff --git a/gobject/tests/Makefile.am b/gobject/tests/Makefile.am
index 33b3e0b01..d1735a2be 100644
--- a/gobject/tests/Makefile.am
+++ b/gobject/tests/Makefile.am
@@ -5,8 +5,10 @@ INCLUDES = -g -I$(top_srcdir) -I$(top_srcdir)/glib $(GLIB_DEBUG_FLAGS)
 noinst_PROGRAMS  = $(TEST_PROGS)
 libgobject_LDADD = ../libgobject-2.0.la $(top_builddir)/gthread/libgthread-2.0.la $(top_builddir)/glib/libglib-2.0.la
 
-TEST_PROGS             += threadtests dynamictests
+TEST_PROGS             += threadtests dynamictests binding
 threadtests_SOURCES	= threadtests.c
 threadtests_LDADD	= $(libgobject_LDADD)
 dynamictests_SOURCES	= dynamictests.c
 dynamictests_LDADD	= $(libgobject_LDADD)
+binding_SOURCES		= binding.c
+binding_LDADD		= $(libgobject_LDADD)
diff --git a/gobject/tests/binding.c b/gobject/tests/binding.c
new file mode 100644
index 000000000..15036fae0
--- /dev/null
+++ b/gobject/tests/binding.c
@@ -0,0 +1,326 @@
+#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);
+}
+
+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);
+
+  return g_test_run ();
+}