lib: add WpExported, a base class for all exported objects

lib/wp/exported.c

+/* WirePlumber
+ *
+ * Copyright © 2019 Collabora Ltd.
+ *    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+/**
+ * SECTION: Exported
+ *
+ * An exported object is an object that is implemented in the local
+ * wireplumber process but is exported to pipewire so that it is
+ * visible to other clients through the registry.
+ *
+ * In PipeWire, an object is normally exported with pw_remote_export() or
+ * by instantiating a "client-something" object on the server and using
+ * the interface of that "client" object to control the exported global
+ * object. In both cases, a proxy is created, which is in total control
+ * of the object. If the proxy is destroyed, all associated objects
+ * - the local exported object, the "client" object and the remote global
+ * object - are destroyed.
+ */
+
+#include "exported.h"
+#include "private.h"
+
+typedef struct _WpExportedPrivate WpExportedPrivate;
+struct _WpExportedPrivate
+{
+  GWeakRef core;
+  GTask *task;
+};
+
+enum {
+  PROP_0,
+  PROP_CORE,
+  PROP_PROXY,
+};
+
+G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (WpExported, wp_exported, G_TYPE_OBJECT)
+
+static void
+wp_exported_init (WpExported * self)
+{
+  WpExportedPrivate *priv = wp_exported_get_instance_private (self);
+
+  g_weak_ref_init (&priv->core, NULL);
+}
+
+static void
+wp_exported_finalize (GObject * object)
+{
+  WpExportedPrivate *priv =
+      wp_exported_get_instance_private (WP_EXPORTED (object));
+
+  g_debug ("%s:%p destroyed", G_OBJECT_TYPE_NAME (object), object);
+
+  g_weak_ref_clear (&priv->core);
+
+  G_OBJECT_CLASS (wp_exported_parent_class)->finalize (object);
+}
+
+static void
+wp_exported_set_property (GObject * object, guint property_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  WpExportedPrivate *priv =
+      wp_exported_get_instance_private (WP_EXPORTED (object));
+
+  switch (property_id) {
+  case PROP_CORE:
+    g_weak_ref_set (&priv->core, g_value_get_object (value));
+    break;
+  default:
+    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+    break;
+  }
+}
+
+static void
+wp_exported_get_property (GObject * object, guint property_id, GValue * value,
+    GParamSpec * pspec)
+{
+  WpExportedPrivate *priv =
+      wp_exported_get_instance_private (WP_EXPORTED (object));
+
+  switch (property_id) {
+  case PROP_CORE:
+    g_value_take_object (value, g_weak_ref_get (&priv->core));
+    break;
+  case PROP_PROXY:
+    g_value_take_object (value, wp_exported_get_proxy (WP_EXPORTED (object)));
+    break;
+  default:
+    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+    break;
+  }
+}
+
+static void
+wp_exported_class_init (WpExportedClass * klass)
+{
+  GObjectClass *object_class = (GObjectClass *) klass;
+
+  object_class->finalize = wp_exported_finalize;
+  object_class->get_property = wp_exported_get_property;
+  object_class->set_property = wp_exported_set_property;
+
+  /* Install the properties */
+
+  g_object_class_install_property (object_class, PROP_CORE,
+      g_param_spec_object ("core", "core", "The WpCore", WP_TYPE_CORE,
+          G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (object_class, PROP_PROXY,
+      g_param_spec_pointer ("proxy", "proxy", "The controlling proxy object",
+          G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
+}
+
+/**
+ * wp_exported_get_core:
+ * @self: the exported object
+ *
+ * Returns: (transfer full): the core that owns this exported object
+ */
+WpCore *
+wp_exported_get_core (WpExported * self)
+{
+  WpExportedPrivate *priv;
+
+  g_return_val_if_fail (WP_IS_EXPORTED (self), NULL);
+
+  priv = wp_exported_get_instance_private (self);
+  return g_weak_ref_get (&priv->core);
+}
+
+void
+wp_exported_export (WpExported * self, GCancellable * cancellable,
+    GAsyncReadyCallback callback, gpointer user_data)
+{
+  WpExportedPrivate *priv;
+
+  g_return_if_fail (WP_IS_EXPORTED (self));
+  g_return_if_fail (WP_EXPORTED_GET_CLASS (self)->export);
+
+  priv = wp_exported_get_instance_private (self);
+  priv->task = g_task_new (self, cancellable, callback, user_data);
+
+  WP_EXPORTED_GET_CLASS (self)->export (self);
+}
+
+gboolean
+wp_exported_export_finish (WpExported * self,
+    GAsyncResult * res, GError ** error)
+{
+  g_return_val_if_fail (WP_IS_EXPORTED (self), FALSE);
+  g_return_val_if_fail (g_task_is_valid (res, self), FALSE);
+
+  return g_task_propagate_boolean (G_TASK (res), error);
+}
+
+void
+wp_exported_notify_export_done (WpExported * self, GError * error)
+{
+  WpExportedPrivate *priv;
+  g_autoptr (WpCore) core = NULL;
+
+  g_return_if_fail (WP_IS_EXPORTED (self));
+
+  priv = wp_exported_get_instance_private (self);
+  g_return_if_fail (priv->task);
+
+  g_task_return_boolean (priv->task, TRUE);
+  g_clear_object (&priv->task);
+
+  core = g_weak_ref_get (&priv->core);
+  if (core)
+    wp_core_register_object (core, g_object_ref (self));
+}
+
+void
+wp_exported_unexport (WpExported * self)
+{
+  WpExportedPrivate *priv;
+  g_autoptr (WpCore) core = NULL;
+
+  g_return_if_fail (WP_IS_EXPORTED (self));
+
+  priv = wp_exported_get_instance_private (self);
+  g_return_if_fail (!priv->task);
+
+  if (WP_EXPORTED_GET_CLASS (self)->unexport)
+    WP_EXPORTED_GET_CLASS (self)->unexport (self);
+
+  core = g_weak_ref_get (&priv->core);
+  if (core)
+    wp_core_remove_object (core, self);
+}
+
+/**
+ * wp_exported_get_proxy:
+ * @self: the exported object
+ *
+ * Returns: (transfer full): the proxy that controls the export to pipewire
+ */
+WpProxy *
+wp_exported_get_proxy (WpExported * self)
+{
+  g_return_val_if_fail (WP_IS_EXPORTED (self), NULL);
+  g_return_val_if_fail (WP_EXPORTED_GET_CLASS (self)->get_proxy, NULL);
+
+  return WP_EXPORTED_GET_CLASS (self)->get_proxy (self);
+}

lib/wp/exported.h

+/* WirePlumber
+ *
+ * Copyright © 2019 Collabora Ltd.
+ *    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef __WIREPLUMBER_EXPORTED_H__
+#define __WIREPLUMBER_EXPORTED_H__
+
+#include <gio/gio.h>
+#include "proxy.h"
+
+G_BEGIN_DECLS
+
+#define WP_TYPE_EXPORTED (wp_exported_get_type ())
+G_DECLARE_DERIVABLE_TYPE (WpExported, wp_exported, WP, EXPORTED, GObject)
+
+struct _WpExportedClass
+{
+  GObjectClass parent_class;
+
+  void (*export) (WpExported * self);
+  void (*unexport) (WpExported * self);
+  WpProxy * (*get_proxy) (WpExported * self);
+};
+
+WpCore * wp_exported_get_core (WpExported * self);
+
+void wp_exported_export (WpExported * self, GCancellable * cancellable,
+    GAsyncReadyCallback callback, gpointer user_data);
+gboolean wp_exported_export_finish (WpExported * self,
+    GAsyncResult * res, GError ** error);
+
+void wp_exported_unexport (WpExported * self);
+
+WpProxy * wp_exported_get_proxy (WpExported * self);
+
+G_END_DECLS
+
+#endif

lib/wp/meson.build

@@ -2,6 +2,7 @@ wp_lib_sources = [
   'core.c',
   'endpoint.c',
   'error.c',
+  'exported.c',
   'factory.c',
   'module.c',
   'monitor.c',
@@ -19,6 +20,7 @@ wp_lib_headers = [
   'core.h',
   'endpoint.h',
   'error.h',
+  'exported.h',
   'factory.h',
   'module.h',
   'monitor.h',

lib/wp/private.h

@@ -10,6 +10,7 @@
 #define __WIREPLUMBER_PRIVATE_H__
 
 #include "core.h"
+#include "exported.h"
 #include "object-manager.h"
 #include "proxy.h"
 
@@ -28,6 +29,10 @@ gpointer wp_core_find_object (WpCore * self, GEqualFunc func,
 void wp_core_register_object (WpCore * self, gpointer obj);
 void wp_core_remove_object (WpCore * self, gpointer obj);
 
+/* exported */
+
+void wp_exported_notify_export_done (WpExported * self, GError * error);
+
 /* global */
 
 typedef struct _WpGlobal WpGlobal;

lib/wp/wp.h

@@ -9,6 +9,7 @@
 #include "core.h"
 #include "endpoint.h"
 #include "error.h"
+#include "exported.h"
 #include "factory.h"
 #include "module.h"
 #include "monitor.h"