lib: add a WpPlugin class

This serves as a base class for daemon plugins, which are implemented
inside modules

lib/wp/plugin.c

@@ -0,0 +1,200 @@
+/* WirePlumber
+ *
+ * Copyright © 2020 Collabora Ltd.
+ *    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+/**
+ * SECTION: plugin
+ * @title: WirePlumber Daemon Plugins
+ */
+
+#define G_LOG_DOMAIN "wp-plugin"
+
+#include "plugin.h"
+#include "private.h"
+
+enum {
+  PROP_0,
+  PROP_MODULE,
+};
+
+typedef struct _WpPluginPrivate WpPluginPrivate;
+struct _WpPluginPrivate
+{
+  GWeakRef module;
+};
+
+/**
+ * WpPlugin:
+ *
+ * #WpPlugin is a base class for objects that provide functionality to the
+ * WirePlumber daemon.
+ *
+ * Typically, a plugin is created within a module and then registered to
+ * make it available for use by the daemon. The daemon is responsible for
+ * calling #WpPluginClass.activate() after all modules have been loaded,
+ * the core is connected and the initial discovery of global objects is
+ * done.
+ */
+G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (WpPlugin, wp_plugin, G_TYPE_OBJECT)
+
+static void
+wp_plugin_init (WpPlugin * self)
+{
+  WpPluginPrivate *priv = wp_plugin_get_instance_private (self);
+  g_weak_ref_init (&priv->module, NULL);
+}
+
+static void
+wp_plugin_dispose (GObject * object)
+{
+  WpPlugin *self = WP_PLUGIN (object);
+
+  wp_plugin_deactivate (self);
+
+  G_OBJECT_CLASS (wp_plugin_parent_class)->dispose (object);
+}
+
+static void
+wp_plugin_finalize (GObject * object)
+{
+  WpPlugin *self = WP_PLUGIN (object);
+  WpPluginPrivate *priv = wp_plugin_get_instance_private (self);
+
+  g_weak_ref_clear (&priv->module);
+
+  G_OBJECT_CLASS (wp_plugin_parent_class)->finalize (object);
+}
+
+static void
+wp_plugin_set_property (GObject * object, guint property_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  WpPlugin *self = WP_PLUGIN (object);
+  WpPluginPrivate *priv = wp_plugin_get_instance_private (self);
+
+  switch (property_id) {
+  case PROP_MODULE:
+    g_weak_ref_set (&priv->module, g_value_get_object (value));
+    break;
+  default:
+    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+    break;
+  }
+}
+
+static void
+wp_plugin_get_property (GObject * object, guint property_id,
+    GValue * value, GParamSpec * pspec)
+{
+  WpPlugin *self = WP_PLUGIN (object);
+  WpPluginPrivate *priv = wp_plugin_get_instance_private (self);
+
+  switch (property_id) {
+  case PROP_MODULE:
+    g_value_take_object (value, g_weak_ref_get (&priv->module));
+    break;
+  default:
+    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+    break;
+  }
+}
+
+static void
+wp_plugin_class_init (WpPluginClass * klass)
+{
+  GObjectClass * object_class = (GObjectClass *) klass;
+
+  object_class->dispose = wp_plugin_dispose;
+  object_class->finalize = wp_plugin_finalize;
+  object_class->set_property = wp_plugin_set_property;
+  object_class->get_property = wp_plugin_get_property;
+
+  /**
+   * WpPlugin:module:
+   * The module that created this plugin.
+   * Implementations should initialize this in the constructor.
+   */
+  g_object_class_install_property (object_class, PROP_MODULE,
+      g_param_spec_object ("module", "module",
+          "The module that owns this plugin", WP_TYPE_MODULE,
+          G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
+}
+
+/**
+ * wp_plugin_register:
+ * @plugin: (transfer full): the plugin
+ *
+ * Registers the plugin to its associated core, making it available for use
+ */
+void
+wp_plugin_register (WpPlugin * plugin)
+{
+  g_autoptr (WpCore) core = wp_plugin_get_core (plugin);
+  g_return_if_fail (WP_IS_CORE (core));
+
+  wp_registry_register_object (wp_core_get_registry (core), plugin);
+}
+
+/**
+ * wp_plugin_get_module:
+ * @self: the plugin
+ *
+ * Returns: (transfer full): the module associated with this plugin
+ */
+WpModule *
+wp_plugin_get_module (WpPlugin * self)
+{
+  g_return_val_if_fail (WP_IS_PLUGIN (self), NULL);
+
+  WpPluginPrivate *priv = wp_plugin_get_instance_private (self);
+  return g_weak_ref_get (&priv->module);
+}
+
+/**
+ * wp_plugin_get_core:
+ * @self: the plugin
+ *
+ * Returns: (transfer full): the core associated with this plugin
+ */
+WpCore *
+wp_plugin_get_core (WpPlugin * self)
+{
+  g_autoptr (WpModule) module = wp_plugin_get_module (self);
+  return module ? wp_module_get_core (module) : NULL;
+}
+
+/**
+ * wp_plugin_activate: (virtual activate)
+ * @self: the plugin
+ *
+ * Activates the plugin. The plugin is required to start any operations only
+ * when this method is called and not before.
+ */
+void
+wp_plugin_activate (WpPlugin * self)
+{
+  g_return_if_fail (WP_IS_PLUGIN (self));
+  g_return_if_fail (WP_PLUGIN_GET_CLASS (self)->activate);
+
+  WP_PLUGIN_GET_CLASS (self)->activate (self);
+}
+
+/**
+ * wp_plugin_deactivate: (virtual deactivate)
+ * @self: the plugin
+ *
+ * Deactivates the plugin. The plugin is required to stop all operations and
+ * release all resources associated with it.
+ */
+void
+wp_plugin_deactivate (WpPlugin * self)
+{
+  g_return_if_fail (WP_IS_PLUGIN (self));
+  g_return_if_fail (WP_PLUGIN_GET_CLASS (self)->deactivate);
+
+  WP_PLUGIN_GET_CLASS (self)->deactivate (self);
+}