controllers: add new proxy control binding

Allows proxying the control interface from one property on one GstObject
to another property (of the same type) in another GstObject.

E.g. in a parent-child relationship, one may need to
gst_object_sync_values() on the child and have a binding (set elsewhere)
on the parent update the value.

Note: that this doesn't solve GObject property forwarding and must be
taken care of by the implementation manually or using GBinding.

https://bugzilla.gnome.org/show_bug.cgi?id=774657

8 files changed, 413 insertions, 0 deletions

diff --git a/docs/libs/gstreamer-libs-docs.sgml b/docs/libs/gstreamer-libs-docs.sgml
index d11da62ca..bca5d2fa7 100644
--- a/docs/libs/gstreamer-libs-docs.sgml
+++ b/docs/libs/gstreamer-libs-docs.sgml
@@ -59,6 +59,7 @@
 
 			<xi:include href="xml/gstargbcontrolbinding.xml" />
 			<xi:include href="xml/gstdirectcontrolbinding.xml" />
+			<xi:include href="xml/gstproxycontrolbinding.xml" />
 
       <xi:include href="xml/gsttimedvaluecontrolsource.xml" />
       <xi:include href="xml/gstinterpolationcontrolsource.xml" />
diff --git a/docs/libs/gstreamer-libs-sections.txt b/docs/libs/gstreamer-libs-sections.txt
index b833357a8..a0f841378 100644
--- a/docs/libs/gstreamer-libs-sections.txt
+++ b/docs/libs/gstreamer-libs-sections.txt
@@ -52,6 +52,23 @@ GST_TYPE_DIRECT_CONTROL_BINDING
 gst_direct_control_binding_get_type
 </SECTION>
 
+<SECTION>
+<FILE>gstproxycontrolbinding</FILE>
+<TITLE>GstProxyControlBinding</TITLE>
+<INCLUDE>libs/controller/gstdirectcontrolbinding.h</INCLUDE>
+gst_proxy_control_binding_new
+<SUBSECTION Standard>
+GstProxyControlBinding
+GstProxyControlBindingClass
+GST_PROXY_CONTROL_BINDING
+GST_PROXY_CONTROL_BINDING_CLASS
+GST_PROXY_CONTROL_BINDING_GET_CLASS
+GST_IS_PROXY_CONTROL_BINDING
+GST_IS_PROXY_CONTROL_BINDING_CLASS
+GST_TYPE_PROXY_CONTROL_BINDING
+gst_proxy_control_binding_get_type
+</SECTION>
+
 # control source classes
 
 <SECTION>
diff --git a/libs/gst/controller/Makefile.am b/libs/gst/controller/Makefile.am
index 5016ea62b..b20a8e7d9 100644
--- a/libs/gst/controller/Makefile.am
+++ b/libs/gst/controller/Makefile.am
@@ -7,6 +7,7 @@ libgstcontroller_@GST_API_VERSION@_include_HEADERS = \
 	gstdirectcontrolbinding.h \
 	gsttimedvaluecontrolsource.h \
 	gstinterpolationcontrolsource.h \
+	gstproxycontrolbinding.h \
 	gsttriggercontrolsource.h \
 	gstlfocontrolsource.h
 
@@ -15,6 +16,7 @@ libgstcontroller_@GST_API_VERSION@_la_SOURCES = \
 	gstdirectcontrolbinding.c \
 	gsttimedvaluecontrolsource.c \
 	gstinterpolationcontrolsource.c \
+	gstproxycontrolbinding.c \
 	gsttriggercontrolsource.c \
 	gstlfocontrolsource.c
 
diff --git a/libs/gst/controller/gstproxycontrolbinding.c b/libs/gst/controller/gstproxycontrolbinding.c
new file mode 100644
index 000000000..ce5cad5d8
--- /dev/null
+++ b/libs/gst/controller/gstproxycontrolbinding.c
@@ -0,0 +1,199 @@
+/*
+ * GStreamer
+ * Copyright (C) 2016 Matthew Waters <matthew@centricular.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+/**
+ * SECTION:gstproxycontrolbinding
+ * @short_description: attachment for forwarding control sources
+ * @see_also: #GstControlBinding
+ *
+ * A #GstControlBinding that forwards requests to another #GstControlBinding
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstproxycontrolbinding.h"
+
+G_DEFINE_TYPE (GstProxyControlBinding,
+    gst_proxy_control_binding, GST_TYPE_CONTROL_BINDING);
+
+static void
+gst_proxy_control_binding_init (GstProxyControlBinding * self)
+{
+  g_weak_ref_init (&self->ref_object, NULL);
+}
+
+static void
+gst_proxy_control_binding_finalize (GObject * object)
+{
+  GstProxyControlBinding *self = (GstProxyControlBinding *) object;
+
+  g_weak_ref_clear (&self->ref_object);
+  g_free (self->property_name);
+
+  G_OBJECT_CLASS (gst_proxy_control_binding_parent_class)->finalize (object);
+}
+
+static gboolean
+gst_proxy_control_binding_sync_values (GstControlBinding * binding,
+    GstObject * object, GstClockTime timestamp, GstClockTime last_sync)
+{
+  GstProxyControlBinding *self = (GstProxyControlBinding *)
+      binding;
+  gboolean ret = TRUE;
+  GstObject *ref_object;
+
+  ref_object = g_weak_ref_get (&self->ref_object);
+  if (ref_object) {
+    GstControlBinding *ref_binding =
+        gst_object_get_control_binding (ref_object, self->property_name);
+    if (ref_binding) {
+      ret = gst_control_binding_sync_values (ref_binding, ref_object,
+          timestamp, last_sync);
+      gst_object_unref (ref_binding);
+    }
+    gst_object_unref (ref_object);
+  }
+
+  return ret;
+}
+
+static GValue *
+gst_proxy_control_binding_get_value (GstControlBinding * binding,
+    GstClockTime timestamp)
+{
+  GstProxyControlBinding *self = (GstProxyControlBinding *)
+      binding;
+  GValue *ret = NULL;
+  GstObject *ref_object;
+
+  ref_object = g_weak_ref_get (&self->ref_object);
+  if (ref_object) {
+    GstControlBinding *ref_binding =
+        gst_object_get_control_binding (ref_object, self->property_name);
+    if (ref_binding) {
+      ret = gst_control_binding_get_value (ref_binding, timestamp);
+      gst_object_unref (ref_binding);
+    }
+    gst_object_unref (ref_object);
+  }
+
+  return ret;
+}
+
+static gboolean
+gst_proxy_control_binding_get_value_array (GstControlBinding * binding,
+    GstClockTime timestamp, GstClockTime interval, guint n_values,
+    gpointer values)
+{
+  GstProxyControlBinding *self = (GstProxyControlBinding *)
+      binding;
+  gboolean ret = FALSE;
+  GstObject *ref_object;
+
+  ref_object = g_weak_ref_get (&self->ref_object);
+  if (ref_object) {
+    GstControlBinding *ref_binding =
+        gst_object_get_control_binding (ref_object, self->property_name);
+    if (ref_binding) {
+      ret = gst_control_binding_get_value_array (ref_binding, timestamp,
+          interval, n_values, values);
+      gst_object_unref (ref_binding);
+    }
+    gst_object_unref (ref_object);
+  }
+
+  return ret;
+}
+
+static gboolean
+gst_proxy_control_binding_get_g_value_array (GstControlBinding *
+    binding, GstClockTime timestamp, GstClockTime interval, guint n_values,
+    GValue * values)
+{
+  GstProxyControlBinding *self = (GstProxyControlBinding *) binding;
+  gboolean ret = FALSE;
+  GstObject *ref_object;
+
+  ref_object = g_weak_ref_get (&self->ref_object);
+  if (ref_object) {
+    GstControlBinding *ref_binding =
+        gst_object_get_control_binding (ref_object, self->property_name);
+    if (ref_binding) {
+      ret = gst_control_binding_get_g_value_array (ref_binding, timestamp,
+          interval, n_values, values);
+      gst_object_unref (ref_binding);
+    }
+    gst_object_unref (ref_object);
+  }
+
+  return ret;
+}
+
+static void
+gst_proxy_control_binding_class_init (GstProxyControlBindingClass * klass)
+{
+  GstControlBindingClass *cb_class = GST_CONTROL_BINDING_CLASS (klass);
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  cb_class->sync_values = gst_proxy_control_binding_sync_values;
+  cb_class->get_value = gst_proxy_control_binding_get_value;
+  cb_class->get_value_array = gst_proxy_control_binding_get_value_array;
+  cb_class->get_g_value_array = gst_proxy_control_binding_get_g_value_array;
+
+  gobject_class->finalize = gst_proxy_control_binding_finalize;
+}
+
+/**
+ * gst_proxy_control_binding_new:
+ * @object: (transfer none): a #GstObject
+ * @property_name: the property name in @object to control
+ * @ref_object: (transfer none): a #GstObject to forward all
+ *              #GstControlBinding requests to
+ * @ref_property_name: the property_name in @ref_object to control
+ *
+ * #GstProxyControlBinding forwards all access to data or sync_values()
+ * requests from @property_name on @object to the control binding at
+ * @ref_property_name on @ref_object.
+ *
+ * Returns: a new #GstControlBinding that proxies the control interface between
+ * properties on different #GstObject's
+ *
+ * Since: 1.12
+ */
+GstControlBinding *
+gst_proxy_control_binding_new (GstObject * object, const gchar * property_name,
+    GstObject * ref_object, const gchar * ref_property_name)
+{
+  GstProxyControlBinding *cb;
+
+  g_return_val_if_fail (GST_IS_OBJECT (object), NULL);
+  g_return_val_if_fail (property_name != NULL, NULL);
+  g_return_val_if_fail (GST_IS_OBJECT (ref_object), NULL);
+  g_return_val_if_fail (ref_property_name != NULL, NULL);
+
+  cb = g_object_new (GST_TYPE_PROXY_CONTROL_BINDING, "object", object,
+      "name", property_name, NULL);
+
+  g_weak_ref_set (&cb->ref_object, ref_object);
+  cb->property_name = g_strdup (ref_property_name);
+
+  return (GstControlBinding *) cb;
+}
diff --git a/libs/gst/controller/gstproxycontrolbinding.h b/libs/gst/controller/gstproxycontrolbinding.h
new file mode 100644
index 000000000..096712d9d
--- /dev/null
+++ b/libs/gst/controller/gstproxycontrolbinding.h
@@ -0,0 +1,83 @@
+/*
+ * GStreamer
+ * Copyright (C) 2016 Matthew Waters <matthew@centricular.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __GST_PROXY_CONTROL_BINDING_H__
+#define __GST_PROXY_CONTROL_BINDING_H__
+
+#include <gst/gst.h>
+
+G_BEGIN_DECLS
+
+GType gst_proxy_control_binding_get_type (void);
+#define GST_TYPE_PROXY_CONTROL_BINDING  (gst_proxy_control_binding_get_type())
+#define GST_PROXY_CONTROL_BINDING(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_PROXY_CONTROL_BINDING,GstProxyControlBinding))
+#define GST_PROXY_CONTROL_BINDING_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_PROXY_CONTROL_BINDING,GstProxyControlBindingClass))
+#define GST_IS_PROXY_CONTROL_BINDING(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_PROXY_CONTROL_BINDING))
+#define GST_IS_PROXY_CONTROL_BINDING_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_PROXY_CONTROL_BINDING))
+#define GST_PROXY_CONTROL_BINDING_GET_CLASS(obj) \
+  (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_CONTOL_SOURCE, GstProxyControlBindingClass))
+
+typedef struct _GstProxyControlBinding GstProxyControlBinding;
+typedef struct _GstProxyControlBindingClass GstProxyControlBindingClass;
+
+/**
+ * GstProxyControlBinding:
+ *
+ * Opaque #GstProxyControlBinding struct
+ */
+struct _GstProxyControlBinding
+{
+  /* <private> */
+  GstControlBinding parent;
+
+  GWeakRef ref_object;
+  gchar *property_name;
+
+  gpointer _padding[GST_PADDING];
+};
+
+/**
+ * GstProxyControlBindingClass:
+ *
+ * Opaque #GstProxyControlBindingClass struct
+ */
+struct _GstProxyControlBindingClass
+{
+  /* <private> */
+  GstControlBindingClass parent_class;
+
+  gpointer _padding[GST_PADDING];
+};
+
+GstControlBinding *     gst_proxy_control_binding_new               (GstObject * object,
+                                                                     const gchar * property_name,
+                                                                     GstObject * ref_object,
+                                                                     const gchar * ref_property_name);
+
+#ifdef G_DEFINE_AUTOPTR_CLEANUP_FUNC
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstProxyControlBinding, gst_object_unref)
+#endif
+G_END_DECLS
+
+#endif /* __GST_PROXY_CONTROL_BINDING_H__ */
diff --git a/libs/gst/controller/meson.build b/libs/gst/controller/meson.build
index c3c784393..861ada525 100644
--- a/libs/gst/controller/meson.build
+++ b/libs/gst/controller/meson.build
@@ -3,6 +3,7 @@ gst_controller_sources = [
   'gstdirectcontrolbinding.c',
   'gsttimedvaluecontrolsource.c',
   'gstinterpolationcontrolsource.c',
+  'gstproxycontrolbinding.c',
   'gsttriggercontrolsource.c',
   'gstlfocontrolsource.c',
 ]
@@ -12,6 +13,7 @@ gst_controller_headers = [
   'gstdirectcontrolbinding.h',
   'gsttimedvaluecontrolsource.h',
   'gstinterpolationcontrolsource.h',
+  'gstproxycontrolbinding.h',
   'gsttriggercontrolsource.h',
   'gstlfocontrolsource.h',
   'controller.h',
diff --git a/tests/check/libs/controller.c b/tests/check/libs/controller.c
index 3a736cd5d..9fdb760d5 100644
--- a/tests/check/libs/controller.c
+++ b/tests/check/libs/controller.c
@@ -30,6 +30,7 @@
 #include <gst/controller/gstlfocontrolsource.h>
 #include <gst/controller/gsttriggercontrolsource.h>
 #include <gst/controller/gstdirectcontrolbinding.h>
+#include <gst/controller/gstproxycontrolbinding.h>
 
 /* enum for text element */
 
@@ -1526,6 +1527,111 @@ GST_START_TEST (controller_trigger_tolerance)
 
 GST_END_TEST;
 
+GST_START_TEST (controller_proxy)
+{
+  GstControlBinding *cb, *cb2;
+  GstControlSource *cs;
+  GstTimedValueControlSource *tvcs;
+  GstElement *elem, *elem2;
+  GstClockTime time;
+  gint int1, int2;
+  GValue gval1 = G_VALUE_INIT, gval2 = G_VALUE_INIT;
+  GValue *val1, *val2;
+
+  elem = gst_element_factory_make ("testobj", NULL);
+  elem2 = gst_element_factory_make ("testobj", NULL);
+
+  /* proxy control binding from elem to elem2 */
+  cb = gst_proxy_control_binding_new (GST_OBJECT (elem), "int",
+      GST_OBJECT (elem2), "int");
+  fail_unless (gst_object_add_control_binding (GST_OBJECT (elem), cb));
+
+  /* test that no proxy does nothing */
+  val1 = gst_control_binding_get_value (cb, 0);
+  fail_unless (val1 == NULL);
+  fail_if (gst_control_binding_get_value_array (cb, 0, 0, 1, &int1));
+  fail_if (gst_control_binding_get_g_value_array (cb, 0, 0, 1, &gval1));
+
+  /* new interpolation control source */
+  cs = gst_trigger_control_source_new ();
+  tvcs = (GstTimedValueControlSource *) cs;
+
+  cb2 = gst_direct_control_binding_new (GST_OBJECT (elem2), "int", cs);
+  fail_unless (gst_object_add_control_binding (GST_OBJECT (elem2), cb2));
+
+  /* set control values */
+  fail_unless (gst_timed_value_control_source_set (tvcs, 0 * GST_SECOND, 0.0));
+  fail_unless (gst_timed_value_control_source_set (tvcs, 1 * GST_SECOND, 1.0));
+
+  /* now pull in values for some timestamps */
+  time = 0 * GST_SECOND;
+  gst_object_sync_values (GST_OBJECT (elem), time);
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int, 0);
+  val1 = gst_control_binding_get_value (cb, time);
+  val2 = gst_control_binding_get_value (cb2, time);
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int,
+      g_value_get_int (val1));
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int,
+      g_value_get_int (val2));
+  fail_unless (gst_control_binding_get_value_array (cb, time, 0, 1, &int1));
+  fail_unless (gst_control_binding_get_value_array (cb2, time, 0, 1, &int2));
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int, int1);
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int, int2);
+  fail_unless (gst_control_binding_get_g_value_array (cb, time, 0, 1, &gval1));
+  fail_unless (gst_control_binding_get_g_value_array (cb2, time, 0, 1, &gval2));
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int,
+      g_value_get_int (&gval1));
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int,
+      g_value_get_int (&gval2));
+  g_value_unset (val1);
+  g_value_unset (val2);
+  g_free (val1);
+  g_free (val2);
+  g_value_unset (&gval1);
+  g_value_unset (&gval2);
+
+  time = 1 * GST_SECOND;
+  gst_object_sync_values (GST_OBJECT (elem), time);
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int, 100);
+  val1 = gst_control_binding_get_value (cb, time);
+  val2 = gst_control_binding_get_value (cb2, time);
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int,
+      g_value_get_int (val1));
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int,
+      g_value_get_int (val2));
+  fail_unless (gst_control_binding_get_value_array (cb, time, 0, 1, &int1));
+  fail_unless (gst_control_binding_get_value_array (cb2, time, 0, 1, &int2));
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int, int1);
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int, int2);
+  fail_unless (gst_control_binding_get_g_value_array (cb, time, 0, 1, &gval1));
+  fail_unless (gst_control_binding_get_g_value_array (cb2, time, 0, 1, &gval2));
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int,
+      g_value_get_int (&gval1));
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int,
+      g_value_get_int (&gval2));
+  g_value_unset (val1);
+  g_value_unset (val2);
+  g_free (val1);
+  g_free (val2);
+  g_value_unset (&gval1);
+  g_value_unset (&gval2);
+
+  /* test syncing on the original control binding */
+  time = 0 * GST_SECOND;
+  gst_object_sync_values (GST_OBJECT (elem2), time);
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int, 0);
+
+  time = 1 * GST_SECOND;
+  gst_object_sync_values (GST_OBJECT (elem2), time);
+  fail_unless_equals_int (GST_TEST_OBJ (elem2)->val_int, 100);
+
+  gst_object_unref (cs);
+  gst_object_unref (elem);
+  gst_object_unref (elem2);
+}
+
+GST_END_TEST;
+
 
 static Suite *
 gst_controller_suite (void)
@@ -1560,6 +1666,7 @@ gst_controller_suite (void)
   tcase_add_test (tc, controller_lfo_triangle);
   tcase_add_test (tc, controller_trigger_exact);
   tcase_add_test (tc, controller_trigger_tolerance);
+  tcase_add_test (tc, controller_proxy);
 
   return s;
 }
diff --git a/win32/common/libgstcontroller.def b/win32/common/libgstcontroller.def
index f539777f5..5ccc4c798 100644
--- a/win32/common/libgstcontroller.def
+++ b/win32/common/libgstcontroller.def
@@ -11,6 +11,8 @@ EXPORTS
 	gst_lfo_control_source_get_type
 	gst_lfo_control_source_new
 	gst_lfo_waveform_get_type
+	gst_proxy_control_binding_get_type
+	gst_proxy_control_binding_new
 	gst_timed_value_control_invalidate_cache
 	gst_timed_value_control_source_find_control_point_iter
 	gst_timed_value_control_source_get_all