[gnome-todo/wip/gbsneto/plugins] plugin-manager: stub out plugin manager

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit a4861949dc6155f7212791c961106d78aa7cb8ab
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Thu Dec 24 00:16:49 2015 -0200

    plugin-manager: stub out plugin manager

 src/gtd-plugin-manager.c |  238 ++++++++++++++++++++++++++++++++++++++++++++++
 src/gtd-plugin-manager.h |   37 +++++++
 2 files changed, 275 insertions(+), 0 deletions(-)
---
diff --git a/src/gtd-plugin-manager.c b/src/gtd-plugin-manager.c
new file mode 100644
index 0000000..0eaba94
--- /dev/null
+++ b/src/gtd-plugin-manager.c
@@ -0,0 +1,238 @@
+/* gtd-plugin-manager.c
+ *
+ * Copyright (C) 2015 Georges Basile Stavracas Neto <georges stavracas gmail com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "interfaces/gtd-activatable.h"
+#include "interfaces/gtd-panel.h"
+#include "interfaces/gtd-provider.h"
+#include "gtd-plugin-manager.h"
+
+#include <libpeas/peas.h>
+
+struct _GtdPluginManager
+{
+  GtdObject          parent;
+
+  GHashTable        *info_to_extension;
+};
+
+G_DEFINE_TYPE (GtdPluginManager, gtd_plugin_manager, GTD_TYPE_OBJECT)
+
+enum
+{
+  PROP_0,
+  LAST_PROP
+};
+
+enum
+{
+  PANEL_REGISTERED,
+  PANEL_UNREGISTERED,
+  PROVIDER_REGISTERED,
+  PROVIDER_UNREGISTERED,
+  NUM_SIGNALS
+};
+
+static guint signals[NUM_SIGNALS] = { 0, };
+
+static void
+gtd_plugin_manager_finalize (GObject *object)
+{
+  GtdPluginManager *self = (GtdPluginManager *)object;
+
+  g_clear_pointer (&self->info_to_extension, g_hash_table_destroy);
+
+  G_OBJECT_CLASS (gtd_plugin_manager_parent_class)->finalize (object);
+}
+
+static void
+gtd_plugin_manager_class_init (GtdPluginManagerClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->finalize = gtd_plugin_manager_finalize;
+
+  signals[PANEL_REGISTERED] = g_signal_new ("panel-registered",
+                                             GTD_TYPE_PLUGIN_MANAGER,
+                                             G_SIGNAL_RUN_FIRST,
+                                             0,
+                                             NULL,
+                                             NULL,
+                                             NULL,
+                                             G_TYPE_NONE,
+                                             1,
+                                             GTD_TYPE_PANEL);
+
+  signals[PANEL_UNREGISTERED] = g_signal_new ("panel-unregistered",
+                                              GTD_TYPE_PLUGIN_MANAGER,
+                                              G_SIGNAL_RUN_FIRST,
+                                              0,
+                                              NULL,
+                                              NULL,
+                                              NULL,
+                                              G_TYPE_NONE,
+                                              1,
+                                              GTD_TYPE_PANEL);
+
+  signals[PROVIDER_REGISTERED] = g_signal_new ("provider-registered",
+                                               GTD_TYPE_PLUGIN_MANAGER,
+                                               G_SIGNAL_RUN_FIRST,
+                                               0,
+                                               NULL,
+                                               NULL,
+                                               NULL,
+                                               G_TYPE_NONE,
+                                               1,
+                                               G_TYPE_POINTER);
+
+  signals[PROVIDER_UNREGISTERED] = g_signal_new ("provider-unregistered",
+                                                 GTD_TYPE_PLUGIN_MANAGER,
+                                                 G_SIGNAL_RUN_FIRST,
+                                                 0,
+                                                 NULL,
+                                                 NULL,
+                                                 NULL,
+                                                 G_TYPE_NONE,
+                                                 1,
+                                                 G_TYPE_POINTER);
+}
+
+static void
+on_provider_added (GtdActivatable   *activatable,
+                   GtdProvider      *provider,
+                   GtdPluginManager *self)
+{
+  g_signal_emit_by_name (self, "provider-registered", provider);
+}
+
+static void
+on_plugin_loaded (PeasEngine       *engine,
+                  PeasPluginInfo   *info,
+                  GtdPluginManager *self)
+{
+  if (peas_engine_provides_extension (engine, info, GTD_TYPE_ACTIVATABLE))
+    {
+      GtdActivatable *activatable;
+      PeasExtension *extension;
+      const GList *l;
+
+      /*
+       * Actually create the plugin object,
+       * which should load all the providers.
+       */
+      extension = peas_engine_create_extension (engine,
+                                                info,
+                                                GTD_TYPE_ACTIVATABLE,
+                                                NULL);
+
+      /* All extensions shall be GtdActivatable impls */
+      activatable = GTD_ACTIVATABLE (extension);
+
+      g_hash_table_insert (self->info_to_extension,
+                           info,
+                           extension);
+
+      /* Load all providers */
+      for (l = gtd_activatable_get_providers (activatable); l != NULL; l = l->next)
+        on_provider_added (activatable, l->data, self);
+
+      g_signal_connect (activatable,
+                        "provider-added",
+                        G_CALLBACK (on_provider_added),
+                        self);
+    }
+}
+
+static void
+setup_plugins (GtdPluginManager *self)
+{
+  PeasEngine *engine;
+  const GList *plugins;
+  const GList *l;
+
+  engine = peas_engine_get_default ();
+
+  /* Load plugins */
+  plugins = peas_engine_get_plugin_list (engine);
+
+  for (l = plugins; l != NULL; l = l->next)
+    peas_engine_load_plugin (engine, l->data);
+}
+
+static void
+setup_engine (GtdPluginManager *self)
+{
+  PeasEngine *engine;
+  const gchar* const *config_dirs;
+  gchar *plugin_dir;
+  gint i;
+
+  config_dirs = g_get_system_data_dirs ();
+  engine = peas_engine_get_default ();
+
+  for (i = 0; config_dirs[i]; i++)
+    {
+      plugin_dir = g_build_filename (config_dirs[i],
+                                     "gnome-todo",
+                                     "plugins",
+                                     NULL);
+
+      /* Let Peas search for plugins in the specified directory */
+      peas_engine_add_search_path (engine,
+                                   plugin_dir,
+                                   NULL);
+
+      g_free (plugin_dir);
+    }
+
+  /* User-installed plugins shall be detected too */
+  plugin_dir = g_build_filename (g_get_user_config_dir (),
+                                 "gnome-todo",
+                                 "plugins",
+                                 NULL);
+
+  peas_engine_add_search_path (engine,
+                               plugin_dir,
+                               NULL);
+
+  g_free (plugin_dir);
+
+  /* Hear about loaded plugins */
+  g_signal_connect_after (engine,
+                          "load-plugin",
+                          G_CALLBACK (on_plugin_loaded),
+                          self);
+}
+
+static void
+gtd_plugin_manager_init (GtdPluginManager *self)
+{
+  self->info_to_extension = g_hash_table_new (g_direct_hash, g_direct_equal);
+
+  gtd_object_set_ready (GTD_OBJECT (self), FALSE);
+
+  setup_engine (self);
+  setup_plugins (self);
+
+  gtd_object_set_ready (GTD_OBJECT (self), TRUE);
+}
+
+GtdPluginManager*
+gtd_plugin_manager_new (void)
+{
+  return g_object_new (GTD_TYPE_PLUGIN_MANAGER, NULL);
+}
diff --git a/src/gtd-plugin-manager.h b/src/gtd-plugin-manager.h
new file mode 100644
index 0000000..f7b1a74
--- /dev/null
+++ b/src/gtd-plugin-manager.h
@@ -0,0 +1,37 @@
+/* gtd-plugin-manager.h
+ *
+ * Copyright (C) 2015 Georges Basile Stavracas Neto <georges stavracas gmail com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GTD_PLUGIN_MANAGER_H
+#define GTD_PLUGIN_MANAGER_H
+
+#include <glib-object.h>
+
+#include "gtd-object.h"
+#include "gtd-types.h"
+
+G_BEGIN_DECLS
+
+#define GTD_TYPE_PLUGIN_MANAGER (gtd_plugin_manager_get_type())
+
+G_DECLARE_FINAL_TYPE (GtdPluginManager, gtd_plugin_manager, GTD, PLUGIN_MANAGER, GtdObject)
+
+GtdPluginManager*    gtd_plugin_manager_new                      (void);
+
+G_END_DECLS
+
+#endif /* GTD_PLUGIN_MANAGER_H */