[gnome-flashback] backends: add GfSettings

[Alberts Muktupāvels <muktupavels src gnome org>]

commit b3027e16c7937d5ffc5432f7ec364fc6196571f5
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sat Sep 9 21:34:23 2017 +0300

    backends: add GfSettings

 backends/Makefile.am           |    2 +
 backends/gf-backend.c          |   34 ++++++
 backends/gf-settings-private.h |   40 +++++++
 backends/gf-settings.c         |  220 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 296 insertions(+), 0 deletions(-)
---
diff --git a/backends/Makefile.am b/backends/Makefile.am
index 9f65c15..01801ee 100644
--- a/backends/Makefile.am
+++ b/backends/Makefile.am
@@ -29,6 +29,8 @@ libbackends_la_SOURCES = \
        gf-backend-x11.c \
        gf-backend.c \
        gf-backend.h \
+       gf-settings-private.h \
+       gf-settings.c \
        $(BUILT_SOURCES) \
        $(NULL)
 
diff --git a/backends/gf-backend.c b/backends/gf-backend.c
index 9e6d5b3..a4ba4eb 100644
--- a/backends/gf-backend.c
+++ b/backends/gf-backend.c
@@ -30,11 +30,18 @@
 #include "gf-backend-native-private.h"
 #include "gf-backend-x11-cm-private.h"
 #include "gf-backend-x11-nested-private.h"
+#include "gf-settings-private.h"
+
+typedef struct
+{
+  GfSettings *settings;
+} GfBackendPrivate;
 
 static void
 initable_iface_init (GInitableIface *initable_iface);
 
 G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GfBackend, gf_backend, G_TYPE_OBJECT,
+                                  G_ADD_PRIVATE (GfBackend)
                                   G_IMPLEMENT_INTERFACE (G_TYPE_INITABLE,
                                                          initable_iface_init))
 
@@ -43,6 +50,14 @@ gf_backend_initable_init (GInitable     *initable,
                           GCancellable  *cancellable,
                           GError       **error)
 {
+  GfBackend *backend;
+  GfBackendPrivate *priv;
+
+  backend = GF_BACKEND (initable);
+  priv = gf_backend_get_instance_private (backend);
+
+  priv->settings = gf_settings_new (backend);
+
   return TRUE;
 }
 
@@ -53,8 +68,27 @@ initable_iface_init (GInitableIface *initable_iface)
 }
 
 static void
+gf_backend_dispose (GObject *object)
+{
+  GfBackend *backend;
+  GfBackendPrivate *priv;
+
+  backend = GF_BACKEND (object);
+  priv = gf_backend_get_instance_private (backend);
+
+  g_clear_object (&priv->settings);
+
+  G_OBJECT_CLASS (gf_backend_parent_class)->dispose (object);
+}
+
+static void
 gf_backend_class_init (GfBackendClass *backend_class)
 {
+  GObjectClass *object_class;
+
+  object_class = G_OBJECT_CLASS (backend_class);
+
+  object_class->dispose = gf_backend_dispose;
 }
 
 static void
diff --git a/backends/gf-settings-private.h b/backends/gf-settings-private.h
new file mode 100644
index 0000000..97fa87a
--- /dev/null
+++ b/backends/gf-settings-private.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2017 Alberts Muktupāvels
+ * Copyright (C) 2017 Red Hat
+ *
+ * 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/>.
+ *
+ * Adapted from mutter:
+ * - src/backends/meta-settings-private.h
+ * - src/meta/meta-settings.h
+ */
+
+#ifndef GF_SETTINGS_PRIVATE_H
+#define GF_SETTINGS_PRIVATE_H
+
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define GF_TYPE_SETTINGS (gf_settings_get_type ())
+G_DECLARE_FINAL_TYPE (GfSettings, gf_settings, GF, SETTINGS, GObject)
+
+GfSettings *gf_settings_new                       (GfBackend  *backend);
+
+gboolean    gf_settings_get_global_scaling_factor (GfSettings *settings,
+                                                   gint       *global_scaling_factor);
+
+G_END_DECLS
+
+#endif
diff --git a/backends/gf-settings.c b/backends/gf-settings.c
new file mode 100644
index 0000000..9fbaf85
--- /dev/null
+++ b/backends/gf-settings.c
@@ -0,0 +1,220 @@
+/*
+ * Copyright (C) 2017 Alberts Muktupāvels
+ * Copyright (C) 2017 Red Hat
+ *
+ * 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/>.
+ *
+ * Adapted from mutter:
+ * - src/backends/meta-settings.c
+ */
+
+#include "config.h"
+
+#include <gio/gio.h>
+
+#include "gf-backend-private.h"
+#include "gf-settings-private.h"
+
+struct _GfSettings
+{
+  GObject    parent;
+
+  GfBackend *backend;
+
+  GSettings *interface;
+
+  gint       global_scaling_factor;
+};
+
+enum
+{
+  PROP_0,
+
+  PROP_BACKEND,
+
+  LAST_PROP
+};
+
+static GParamSpec *settings_properties[LAST_PROP] = { NULL };
+
+enum
+{
+  GLOBAL_SCALING_FACTOR_CHANGED,
+
+  LAST_SIGNAL
+};
+
+static guint settings_signals[LAST_SIGNAL] = { 0 };
+
+G_DEFINE_TYPE (GfSettings, gf_settings, G_TYPE_OBJECT)
+
+static gboolean
+update_global_scaling_factor (GfSettings *settings)
+{
+  gint scale;
+
+  scale = (gint) g_settings_get_uint (settings->interface, "scaling-factor");
+
+  if (settings->global_scaling_factor != scale)
+    {
+      settings->global_scaling_factor = scale;
+      return TRUE;
+    }
+
+  return FALSE;
+}
+
+static void
+interface_changed_cb (GSettings   *interface,
+                      const gchar *key,
+                      GfSettings  *settings)
+{
+  if (g_str_equal (key, "scaling-factor"))
+    {
+      if (update_global_scaling_factor (settings))
+        g_signal_emit (settings, settings_signals[GLOBAL_SCALING_FACTOR_CHANGED], 0);
+    }
+}
+
+static void
+gf_settings_dispose (GObject *object)
+{
+  GfSettings *settings;
+
+  settings = GF_SETTINGS (object);
+
+  g_clear_object (&settings->interface);
+  settings->backend = NULL;
+
+  G_OBJECT_CLASS (gf_settings_parent_class)->dispose (object);
+}
+
+static void
+gf_settings_get_property (GObject    *object,
+                          guint       property_id,
+                          GValue     *value,
+                          GParamSpec *pspec)
+{
+  GfSettings *settings;
+
+  settings = GF_SETTINGS (object);
+
+  switch (property_id)
+    {
+      case PROP_BACKEND:
+        g_value_set_object (value, settings->backend);
+        break;
+
+      default:
+        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+        break;
+    }
+}
+
+static void
+gf_settings_set_property (GObject      *object,
+                          guint         property_id,
+                          const GValue *value,
+                          GParamSpec   *pspec)
+{
+  GfSettings *settings;
+
+  settings = GF_SETTINGS (object);
+
+  switch (property_id)
+    {
+      case PROP_BACKEND:
+        settings->backend = g_value_get_object (value);
+        break;
+
+      default:
+        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+        break;
+    }
+}
+
+static void
+gf_settings_install_properties (GObjectClass *object_class)
+{
+  settings_properties[PROP_BACKEND] =
+    g_param_spec_object ("backend",
+                         "GfBackend",
+                         "GfBackend",
+                         GF_TYPE_BACKEND,
+                         G_PARAM_WRITABLE |
+                         G_PARAM_CONSTRUCT_ONLY |
+                         G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (object_class, LAST_PROP,
+                                     settings_properties);
+}
+
+static void
+gf_settings_install_signals (GObjectClass *object_class)
+{
+  settings_signals[GLOBAL_SCALING_FACTOR_CHANGED] =
+    g_signal_new ("global-scaling-factor-changed",
+                  G_TYPE_FROM_CLASS (object_class), G_SIGNAL_RUN_LAST,
+                  0, NULL, NULL, NULL, G_TYPE_NONE, 0);
+}
+
+static void
+gf_settings_class_init (GfSettingsClass *settings_class)
+{
+  GObjectClass *object_class;
+
+  object_class = G_OBJECT_CLASS (settings_class);
+
+  object_class->dispose = gf_settings_dispose;
+  object_class->get_property = gf_settings_get_property;
+  object_class->set_property = gf_settings_set_property;
+
+  gf_settings_install_properties (object_class);
+  gf_settings_install_signals (object_class);
+}
+
+static void
+gf_settings_init (GfSettings *settings)
+{
+  settings->interface = g_settings_new ("org.gnome.desktop.interface");
+
+  g_signal_connect (settings->interface, "changed",
+                    G_CALLBACK (interface_changed_cb), settings);
+
+  update_global_scaling_factor (settings);
+}
+
+GfSettings *
+gf_settings_new (GfBackend *backend)
+{
+  GfSettings *settings;
+
+  settings = g_object_new (GF_TYPE_SETTINGS,
+                           "backend", backend,
+                           NULL);
+
+  return settings;
+}
+
+gboolean
+gf_settings_get_global_scaling_factor (GfSettings *settings,
+                                       gint       *global_scaling_factor)
+{
+  if (settings->global_scaling_factor == 0)
+    return FALSE;
+
+  *global_scaling_factor = settings->global_scaling_factor;
+
+  return TRUE;
+}