[gnome-calendar/gnome-3-24] clock: introduce GcalClock

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

commit 6b290b41c9f53982e6cd3a19f0e22339e35ecb5a
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Tue May 16 14:29:33 2017 -0300

    clock: introduce GcalClock
    
    GcalClock is an internal clock for GNOME Calendar that
    sends a few utility signals, such as :day-changed and
    :minute-changed.
    
    It also watches for suspend/resume events to properly
    send the signal right after the resume.

 src/Makefile.am  |    4 +-
 src/gcal-clock.c |  284 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/gcal-clock.h |   35 +++++++
 3 files changed, 322 insertions(+), 1 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index 270e703..380f3a1 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -42,8 +42,10 @@ gnome_calendar_SOURCES =                                  \
     views/gcal-week-view.h                                \
     views/gcal-year-view.c                                \
     views/gcal-year-view.h                                \
-    gcal-application.h                                    \
     gcal-application.c                                    \
+    gcal-application.h                                    \
+    gcal-clock.c                                          \
+    gcal-clock.h                                          \
     gcal-date-chooser-day.c                               \
     gcal-date-chooser-day.h                               \
     gcal-date-chooser.c                                   \
diff --git a/src/gcal-clock.c b/src/gcal-clock.c
new file mode 100644
index 0000000..cb4afec
--- /dev/null
+++ b/src/gcal-clock.c
@@ -0,0 +1,284 @@
+/* gcal-clock.c
+ *
+ * Copyright (C) 2017 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/>.
+ */
+
+#define G_LOG_DOMAIN "GcalClock"
+
+#include "gcal-clock.h"
+#include "gcal-debug.h"
+#include "gcal-utils.h"
+
+#include <gio/gio.h>
+
+struct _GcalClock
+{
+  GObject             parent;
+
+  guint               timeout_id;
+
+  GDateTime          *current;
+
+  GDBusProxy         *proxy;
+  GCancellable       *cancellable;
+};
+
+static gboolean      timeout_cb                                  (gpointer user_data);
+
+G_DEFINE_TYPE (GcalClock, gcal_clock, G_TYPE_OBJECT)
+
+enum
+{
+  MINUTE_CHANGED,
+  HOUR_CHANGED,
+  DAY_CHANGED,
+  NUM_SIGNALS
+};
+
+static guint signals[NUM_SIGNALS] = { 0, };
+
+/*
+ * Auxiliary methods
+ */
+
+static void
+update_current_date (GcalClock *self)
+{
+  g_autoptr (GDateTime) now;
+  gboolean minute_changed;
+  gboolean hour_changed;
+  gboolean day_changed;
+
+  GCAL_ENTRY;
+
+  now = g_date_time_new_now_local ();
+
+  day_changed = g_date_time_get_year (now) != g_date_time_get_year (self->current) ||
+                g_date_time_get_day_of_year (now) != g_date_time_get_day_of_year (self->current);
+  hour_changed = day_changed || g_date_time_get_hour (now) != g_date_time_get_hour (self->current);
+  minute_changed = hour_changed || g_date_time_get_minute (now) != g_date_time_get_minute (self->current);
+
+  if (day_changed)
+    g_signal_emit (self, signals[DAY_CHANGED], 0);
+
+  if (hour_changed)
+    g_signal_emit (self, signals[HOUR_CHANGED], 0);
+
+  if (minute_changed)
+    g_signal_emit (self, signals[MINUTE_CHANGED], 0);
+
+  g_debug ("Updating clock time");
+
+  gcal_clear_datetime (&self->current);
+  self->current = g_date_time_ref (now);
+
+  GCAL_EXIT;
+}
+
+static void
+schedule_update_timeout (GcalClock *self)
+{
+  g_autoptr (GDateTime) now;
+  guint seconds_between;
+
+  /* Remove the previous timeout if we came from resume */
+  if (self->timeout_id > 0)
+    {
+      g_source_remove (self->timeout_id);
+      self->timeout_id = 0;
+    }
+
+  now = g_date_time_new_now_local ();
+
+  seconds_between = 60 - g_date_time_get_second (now);
+
+  self->timeout_id = g_timeout_add_seconds (seconds_between, timeout_cb, self);
+
+  g_debug ("Scheduling update for %d seconds", seconds_between);
+}
+
+/*
+ * Callbacks
+ */
+
+static gboolean
+timeout_cb (gpointer user_data)
+{
+  GcalClock *self = user_data;
+
+  self->timeout_id = 0;
+
+  update_current_date (self);
+  schedule_update_timeout (self);
+
+  return G_SOURCE_REMOVE;
+}
+
+static void
+logind_signal_received_cb (GDBusProxy  *logind,
+                           const gchar *sender,
+                           const gchar *signal,
+                           GVariant    *params,
+                           GcalClock   *self)
+{
+  GVariant *child;
+  gboolean resuming;
+
+  if (!g_str_equal (signal, "PrepareForSleep"))
+    return;
+
+  child = g_variant_get_child_value (params, 0);
+  resuming = !g_variant_get_boolean (child);
+
+  /* Only emit :update when resuming */
+  if (resuming)
+    {
+      update_current_date (self);
+      schedule_update_timeout (self);
+    }
+
+  g_clear_pointer (&child, g_variant_unref);
+}
+
+static void
+login_proxy_acquired_cb (GObject      *source,
+                         GAsyncResult *res,
+                         gpointer      user_data)
+{
+  GcalClock *self;
+  GError *error;
+
+  self = GCAL_CLOCK (user_data);
+  error = NULL;
+
+  self->proxy = g_dbus_proxy_new_for_bus_finish (res, &error);
+
+  if (error)
+    {
+      g_warning ("Error acquiring logind DBus proxy: %s", error->message);
+      g_clear_error (&error);
+      return;
+    }
+
+  g_signal_connect (self->proxy,
+                    "g-signal",
+                    G_CALLBACK (logind_signal_received_cb),
+                    self);
+
+  g_debug ("Successfully acquired logind DBus proxy");
+}
+
+static void
+gcal_clock_finalize (GObject *object)
+{
+  GcalClock *self = (GcalClock *)object;
+
+  g_cancellable_cancel (self->cancellable);
+
+  if (self->timeout_id > 0)
+    {
+      g_source_remove (self->timeout_id);
+      self->timeout_id = 0;
+    }
+
+  gcal_clear_datetime (&self->current);
+
+  g_clear_object (&self->cancellable);
+  g_clear_object (&self->proxy);
+
+  G_OBJECT_CLASS (gcal_clock_parent_class)->finalize (object);
+}
+
+static void
+gcal_clock_get_property (GObject    *object,
+                         guint       prop_id,
+                         GValue     *value,
+                         GParamSpec *pspec)
+{
+  G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+}
+
+static void
+gcal_clock_set_property (GObject      *object,
+                         guint         prop_id,
+                         const GValue *value,
+                         GParamSpec   *pspec)
+{
+  G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+}
+
+static void
+gcal_clock_class_init (GcalClockClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->finalize = gcal_clock_finalize;
+  object_class->get_property = gcal_clock_get_property;
+  object_class->set_property = gcal_clock_set_property;
+
+  signals[DAY_CHANGED] = g_signal_new ("day-changed",
+                                       GCAL_TYPE_CLOCK,
+                                       G_SIGNAL_RUN_LAST,
+                                       0, NULL, NULL, NULL,
+                                       G_TYPE_NONE,
+                                       0);
+
+  signals[HOUR_CHANGED] = g_signal_new ("hour-changed",
+                                        GCAL_TYPE_CLOCK,
+                                        G_SIGNAL_RUN_LAST,
+                                        0, NULL, NULL, NULL,
+                                        G_TYPE_NONE,
+                                        0);
+
+  signals[MINUTE_CHANGED] = g_signal_new ("minute-changed",
+                                          GCAL_TYPE_CLOCK,
+                                          G_SIGNAL_RUN_LAST,
+                                          0, NULL, NULL, NULL,
+                                          G_TYPE_NONE,
+                                          0);
+}
+
+static void
+gcal_clock_init (GcalClock *self)
+{
+  self->current = g_date_time_new_now_local ();
+  self->cancellable = g_cancellable_new ();
+
+  g_dbus_proxy_new_for_bus (G_BUS_TYPE_SYSTEM,
+                            G_DBUS_PROXY_FLAGS_NONE,
+                            NULL,
+                            "org.freedesktop.login1",
+                            "/org/freedesktop/login1",
+                            "org.freedesktop.login1.Manager",
+                            self->cancellable,
+                            login_proxy_acquired_cb,
+                            self);
+
+  schedule_update_timeout (self);
+}
+
+/**
+ * gcal_clock_new:
+ *
+ * Creates a new #GcalClock.
+ *
+ * Returns: (transfer full): a newly-allocated #GcalClock.
+ */
+GcalClock*
+gcal_clock_new (void)
+{
+  return g_object_new (GCAL_TYPE_CLOCK, NULL);
+}
diff --git a/src/gcal-clock.h b/src/gcal-clock.h
new file mode 100644
index 0000000..96352ca
--- /dev/null
+++ b/src/gcal-clock.h
@@ -0,0 +1,35 @@
+/* gcal-clock.h
+ *
+ * Copyright (C) 2017 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 GCAL_CLOCK_H
+#define GCAL_CLOCK_H
+
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define GCAL_TYPE_CLOCK (gcal_clock_get_type())
+
+G_DECLARE_FINAL_TYPE (GcalClock, gcal_clock, GCAL, CLOCK, GObject)
+
+GcalClock*           gcal_clock_new                              (void);
+
+G_END_DECLS
+
+#endif /* GCAL_CLOCK_H */
+