[gnome-settings-daemon] power: Implement screen brightness cycle up action

[Benjamin Berg <bberg src gnome org>]

commit 61aa8b8c54148a1d8ae93cabe2c6a9923ce74d68
Author: Jian-Hong Pan <jian-hong endlessm com>
Date:   Fri Mar 29 15:04:16 2019 +0800

    power: Implement screen brightness cycle up action
    
    Implement the screen brightness cycle up action for the
    SCREEN_BRIGHTNESS_CYCLE_KEY media-key.
    
    GNOME/gnome-settings-daemon#117

 plugins/power/gsd-backlight.c     | 66 ++++++++++++++++++++++++++++++++++++---
 plugins/power/gsd-backlight.h     |  7 +++++
 plugins/power/gsd-power-manager.c |  8 +++++
 3 files changed, 77 insertions(+), 4 deletions(-)
---
diff --git a/plugins/power/gsd-backlight.c b/plugins/power/gsd-backlight.c
index e60c649d..304c6d57 100644
--- a/plugins/power/gsd-backlight.c
+++ b/plugins/power/gsd-backlight.c
@@ -582,8 +582,8 @@ gsd_backlight_step_up_async (GsdBacklight *backlight,
  *
  * For simplicity it is also valid to call gsd_backlight_set_brightness_finish()
  * allowing sharing the callback routine for calls to
- * gsd_backlight_set_brightness_async(), gsd_backlight_step_up_async() and
- * gsd_backlight_step_down_async().
+ * gsd_backlight_set_brightness_async(), gsd_backlight_step_up_async(),
+ * gsd_backlight_step_down_async() and gsd_backlight_cycle_up_async().
  *
  * Returns: The brightness in percent that was set.
  **/
@@ -628,8 +628,8 @@ gsd_backlight_step_down_async (GsdBacklight *backlight,
  *
  * For simplicity it is also valid to call gsd_backlight_set_brightness_finish()
  * allowing sharing the callback routine for calls to
- * gsd_backlight_set_brightness_async(), gsd_backlight_step_up_async() and
- * gsd_backlight_step_down_async().
+ * gsd_backlight_set_brightness_async(), gsd_backlight_step_up_async(),
+ * gsd_backlight_step_down_async() and gsd_backlight_cycle_up_async().
  *
  * Returns: The brightness in percent that was set.
  **/
@@ -641,6 +641,64 @@ gsd_backlight_step_down_finish (GsdBacklight *backlight,
         return g_task_propagate_int (G_TASK (res), error);
 }
 
+/**
+ * gsd_backlight_cycle_up_async
+ * @backlight: a #GsdBacklight
+ * @cancellable: an optional #GCancellable, NULL to ignore
+ * @callback: the #GAsyncReadyCallback invoked for cycle up to be finished
+ * @user_data: the #gpointer passed to the callback
+ *
+ * Start a brightness cycle up operation by gsd_backlight_cycle_up_async().
+ * The brightness will be stepped up if it is not already at the maximum.
+ * If it is already at the maximum, it will be set to the minimum brightness.
+ **/
+void
+gsd_backlight_cycle_up_async (GsdBacklight *backlight,
+                              GCancellable *cancellable,
+                              GAsyncReadyCallback callback,
+                              gpointer user_data)
+{
+        if (backlight->brightness_target < backlight->brightness_max)
+                gsd_backlight_step_up_async (backlight,
+                                             cancellable,
+                                             callback,
+                                             user_data);
+        else
+                gsd_backlight_set_brightness_val_async (backlight,
+                                                        backlight->brightness_min,
+                                                        cancellable,
+                                                        callback,
+                                                        user_data);
+}
+
+/**
+ * gsd_backlight_cycle_up_finish
+ * @backlight: a #GsdBacklight
+ * @res: the #GAsyncResult passed to the callback
+ * @error: #GError return address
+ *
+ * Finish an operation started by gsd_backlight_cycle_up_async(). Will return
+ * the value that was actually set (which may be different because of rounding
+ * or as multiple set actions were queued up).
+ *
+ * Please note that a call to gsd_backlight_get_brightness() may not in fact
+ * return the same value if further operations to set the value are pending.
+ *
+ * For simplicity it is also valid to call gsd_backlight_set_brightness_finish()
+ * allowing sharing the callback routine for calls to
+ * gsd_backlight_set_brightness_async(), gsd_backlight_step_up_async(),
+ * gsd_backlight_step_down_async() and gsd_backlight_cycle_up_async().
+ *
+ * Returns: The brightness in percent that was set.
+ **/
+gint
+gsd_backlight_cycle_up_finish (GsdBacklight *backlight,
+                               GAsyncResult *res,
+                               GError **error)
+{
+        return g_task_propagate_int (G_TASK (res), error);
+}
+
 /**
  * gsd_backlight_get_output_id
  * @backlight: a #GsdBacklight
diff --git a/plugins/power/gsd-backlight.h b/plugins/power/gsd-backlight.h
index 2d4f3339..71086a32 100644
--- a/plugins/power/gsd-backlight.h
+++ b/plugins/power/gsd-backlight.h
@@ -49,6 +49,10 @@ void gsd_backlight_step_down_async       (GsdBacklight         *backlight,
                                           GCancellable         *cancellable,
                                           GAsyncReadyCallback   callback,
                                           gpointer              user_data);
+void gsd_backlight_cycle_up_async        (GsdBacklight         *backlight,
+                                          GCancellable         *cancellable,
+                                          GAsyncReadyCallback   callback,
+                                          gpointer              user_data);
 
 gint gsd_backlight_set_brightness_finish (GsdBacklight         *backlight,
                                           GAsyncResult         *res,
@@ -62,6 +66,9 @@ gint gsd_backlight_step_down_finish      (GsdBacklight         *backlight,
                                           GAsyncResult         *res,
                                           GError              **error);
 
+gint gsd_backlight_cycle_up_finish       (GsdBacklight         *backlight,
+                                          GAsyncResult         *res,
+                                          GError              **error);
 
 gint gsd_backlight_get_output_id         (GsdBacklight         *backlight);
 GsdBacklight* gsd_backlight_new          (GnomeRRScreen        *screen,
diff --git a/plugins/power/gsd-power-manager.c b/plugins/power/gsd-power-manager.c
index f82392b2..6af787f5 100644
--- a/plugins/power/gsd-power-manager.c
+++ b/plugins/power/gsd-power-manager.c
@@ -96,6 +96,10 @@ static const gchar introspection_xml[] =
 "      <arg type='i' name='new_percentage' direction='out'/>"
 "      <arg type='i' name='output_id' direction='out'/>"
 "    </method>"
+"    <method name='Cycle'>"
+"      <arg type='i' name='new_percentage' direction='out'/>"
+"      <arg type='i' name='output_id' direction='out'/>"
+"    </method>"
 "  </interface>"
 "  <interface name='org.gnome.SettingsDaemon.Power.Keyboard'>"
 "    <property name='Brightness' type='i' access='readwrite'/>"
@@ -2843,6 +2847,10 @@ handle_method_call_screen (GsdPowerManager *manager,
                 g_debug ("screen step down");
                 gsd_backlight_step_down_async (manager->backlight, NULL, backlight_brightness_step_cb, 
invocation);
 
+        } else if (g_strcmp0 (method_name, "Cycle") == 0) {
+                g_debug ("screen cycle up");
+                gsd_backlight_cycle_up_async (manager->backlight, NULL, backlight_brightness_step_cb, 
invocation);
+
         } else {
                 g_assert_not_reached ();
         }