/* GIO - GLib Input, Output and Streaming Library

 *

 * Copyright 2019 Red Hat, Inc.

 *

 * SPDX-License-Identifier: LGPL-2.1-or-later

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General

 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.

 */

#include "config.h"

#include "gmemorymonitor.h"

#include "gmemorymonitordbus.h"

#include "gioerror.h"

#include "ginitable.h"

#include "giomodule-priv.h"

#include "glibintl.h"

#include "glib/gstdio.h"

#include "gcancellable.h"

#include "gdbusproxy.h"

#include "gdbusnamewatching.h"

#define G_MEMORY_MONITOR_DBUS_GET_INITABLE_IFACE(o) (G_TYPE_INSTANCE_GET_INTERFACE ((o), G_TYPE_INITABLE, GInitable))

static void g_memory_monitor_dbus_iface_init (GMemoryMonitorInterface *iface);

static void g_memory_monitor_dbus_initable_iface_init (GInitableIface *iface);

struct _GMemoryMonitorDBus

{

  GObject parent_instance;

  guint watch_id;

  GCancellable *cancellable;

  GDBusProxy *proxy;

  gulong signal_id;

};

G_DEFINE_TYPE_WITH_CODE (GMemoryMonitorDBus, g_memory_monitor_dbus, G_TYPE_OBJECT,

                         G_IMPLEMENT_INTERFACE (G_TYPE_INITABLE,

                                                g_memory_monitor_dbus_initable_iface_init)

                         G_IMPLEMENT_INTERFACE (G_TYPE_MEMORY_MONITOR,

                                                g_memory_monitor_dbus_iface_init)

                         _g_io_modules_ensure_extension_points_registered ();

                         g_io_extension_point_implement (G_MEMORY_MONITOR_EXTENSION_POINT_NAME,

                                                         g_define_type_id,

                                                         "dbus",

                                                         30))

static void

g_memory_monitor_dbus_init (GMemoryMonitorDBus *dbus)

{

}

static void

proxy_signal_cb (GDBusProxy         *proxy,

                 const gchar        *sender_name,

                 const gchar        *signal_name,

                 GVariant           *parameters,

                 GMemoryMonitorDBus *dbus)

{

  guint8 level;

  if (g_strcmp0 (signal_name, "LowMemoryWarning") != 0)

    return;

  if (parameters == NULL)

    return;

  g_variant_get (parameters, "(y)", &level);

  g_signal_emit_by_name (dbus, "low-memory-warning", level);

}

static void

lmm_proxy_cb (GObject      *source_object,

              GAsyncResult *res,

              gpointer      user_data)

{

  GMemoryMonitorDBus *dbus = user_data;

  GDBusProxy *proxy;

  GError *error = NULL;

  proxy = g_dbus_proxy_new_finish (res, &error);

  if (!proxy)

    {

      g_debug ("Failed to create LowMemoryMonitor D-Bus proxy: %s",

               error->message);

      g_error_free (error);

      return;

    }

  dbus->signal_id = g_signal_connect (G_OBJECT (proxy), "g-signal",

                                      G_CALLBACK (proxy_signal_cb), dbus);

  dbus->proxy = proxy;

}

static void

lmm_appeared_cb (GDBusConnection *connection,

                 const gchar     *name,

                 const gchar     *name_owner,

                 gpointer         user_data)

{

  GMemoryMonitorDBus *dbus = user_data;

  g_dbus_proxy_new (connection,

                    G_DBUS_PROXY_FLAGS_DO_NOT_AUTO_START,

                    NULL,

                    "org.freedesktop.LowMemoryMonitor",

                    "/org/freedesktop/LowMemoryMonitor",

                    "org.freedesktop.LowMemoryMonitor",

                    dbus->cancellable,

                    lmm_proxy_cb,

                    dbus);

}

static void

lmm_vanished_cb (GDBusConnection *connection,

                 const gchar     *name,

                 gpointer         user_data)

{

  GMemoryMonitorDBus *dbus = user_data;

  g_clear_signal_handler (&dbus->signal_id, dbus->proxy);

  g_clear_object (&dbus->proxy);

}

static gboolean

g_memory_monitor_dbus_initable_init (GInitable     *initable,

                                     GCancellable  *cancellable,

                                     GError       **error)

{

  GMemoryMonitorDBus *dbus = G_MEMORY_MONITOR_DBUS (initable);

  dbus->cancellable = g_cancellable_new ();

  dbus->watch_id = g_bus_watch_name (G_BUS_TYPE_SYSTEM,

                                     "org.freedesktop.LowMemoryMonitor",

                                     G_BUS_NAME_WATCHER_FLAGS_AUTO_START,

                                     lmm_appeared_cb,

                                     lmm_vanished_cb,

                                     dbus,

                                     NULL);

  return TRUE;

}

static void

g_memory_monitor_dbus_finalize (GObject *object)

{

  GMemoryMonitorDBus *dbus = G_MEMORY_MONITOR_DBUS (object);

  g_cancellable_cancel (dbus->cancellable);

  g_clear_object (&dbus->cancellable);

  g_clear_signal_handler (&dbus->signal_id, dbus->proxy);

  g_clear_object (&dbus->proxy);

  g_clear_handle_id (&dbus->watch_id, g_bus_unwatch_name);

  G_OBJECT_CLASS (g_memory_monitor_dbus_parent_class)->finalize (object);

}

static void

g_memory_monitor_dbus_class_init (GMemoryMonitorDBusClass *nl_class)

{

  GObjectClass *gobject_class = G_OBJECT_CLASS (nl_class);

  gobject_class->finalize = g_memory_monitor_dbus_finalize;

}

static void

g_memory_monitor_dbus_iface_init (GMemoryMonitorInterface *monitor_iface)

{

}

static void

g_memory_monitor_dbus_initable_iface_init (GInitableIface *iface)

{

  iface->init = g_memory_monitor_dbus_initable_init;

}