[Linux] read settings from XDG desktop portal if available

jpnurmi · jpnurmi · commit a4d8546ca014 · 2022-05-04T14:10:09.000+02:00
Fixes: flutter/flutter#101438
diff --git a/shell/platform/linux/BUILD.gn b/shell/platform/linux/BUILD.gn
@@ -131,6 +131,7 @@ source_set("flutter_linux_sources") {
     "fl_renderer_headless.cc",
     "fl_settings.cc",
     "fl_settings_plugin.cc",
+    "fl_settings_portal.cc",
     "fl_standard_message_codec.cc",
     "fl_standard_method_codec.cc",
     "fl_string_codec.cc",
@@ -208,6 +209,7 @@ executable("flutter_linux_unittests") {
     "fl_pixel_buffer_texture_test.cc",
     "fl_plugin_registrar_test.cc",
     "fl_settings_plugin_test.cc",
+    "fl_settings_portal_test.cc",
     "fl_standard_message_codec_test.cc",
     "fl_standard_method_codec_test.cc",
     "fl_string_codec_test.cc",
diff --git a/shell/platform/linux/fl_settings.cc b/shell/platform/linux/fl_settings.cc
@@ -4,6 +4,7 @@
 
 #include "flutter/shell/platform/linux/fl_settings.h"
 #include "flutter/shell/platform/linux/fl_gnome_settings.h"
+#include "flutter/shell/platform/linux/fl_settings_portal.h"
 
 G_DEFINE_INTERFACE(FlSettings, fl_settings, G_TYPE_OBJECT)
 
@@ -44,6 +45,9 @@ void fl_settings_emit_changed(FlSettings* self) {
 }
 
 FlSettings* fl_settings_new() {
-  // TODO(jpnurmi): add support for other desktop environments
-  return FL_SETTINGS(fl_gnome_settings_new());
+  g_autoptr(FlSettingsPortal) portal = fl_settings_portal_new(nullptr);
+  if (!fl_settings_portal_start(portal)) {
+    return fl_gnome_settings_new();
+  }
+  return FL_SETTINGS(g_object_ref(portal));
 }
diff --git a/shell/platform/linux/fl_settings_portal.cc b/shell/platform/linux/fl_settings_portal.cc
@@ -0,0 +1,251 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "flutter/shell/platform/linux/fl_settings_portal.h"
+
+#include <gio/gio.h>
+#include <glib.h>
+
+static constexpr char kPortalName[] = "org.freedesktop.portal.Desktop";
+static constexpr char kPortalPath[] = "/org/freedesktop/portal/desktop";
+static constexpr char pPortalSettings[] = "org.freedesktop.portal.Settings";
+
+struct FlSetting {
+  const gchar* ns;
+  const gchar* key;
+  const GVariantType* type;
+};
+
+static constexpr char kXdgAppearance[] = "org.freedesktop.appearance";
+static const FlSetting kColorScheme = {
+    kXdgAppearance,
+    "color-scheme",
+    G_VARIANT_TYPE_UINT32,
+};
+
+static constexpr char kGnomeDesktopInterface[] = "org.gnome.desktop.interface";
+static const FlSetting kClockFormat = {
+    kGnomeDesktopInterface,
+    "clock-format",
+    G_VARIANT_TYPE_STRING,
+};
+static const FlSetting kTextScalingFactor = {
+    kGnomeDesktopInterface,
+    "text-scaling-factor",
+    G_VARIANT_TYPE_DOUBLE,
+};
+
+static const FlSetting all_settings[] = {
+    kClockFormat,
+    kColorScheme,
+    kTextScalingFactor,
+};
+
+static constexpr char kClockFormat12Hour[] = "12h";
+
+typedef enum { DEFAULT, PREFER_DARK, PREFER_LIGHT } ColorScheme;
+
+struct _FlSettingsPortal {
+  GObject parent_instance;
+
+  GDBusProxy* dbus_proxy;
+  GVariantDict* values;
+};
+
+static void fl_settings_portal_iface_init(FlSettingsInterface* iface);
+
+G_DEFINE_TYPE_WITH_CODE(FlSettingsPortal,
+                        fl_settings_portal,
+                        G_TYPE_OBJECT,
+                        G_IMPLEMENT_INTERFACE(fl_settings_get_type(),
+                                              fl_settings_portal_iface_init))
+
+#define FL_SETTINGS_PORTAL_GET_PRIVATE(portal) \
+  ((FlSettingsPortalPrivate*)fl_settings_portal_get_instance_private(portal))
+
+static const gchar* fl_settings_portal_format_key(const FlSetting* setting) {
+  return g_strconcat(setting->ns, "::", setting->key, nullptr);
+}
+
+static gboolean fl_settings_portal_get_value(FlSettingsPortal* self,
+                                             const FlSetting* setting,
+                                             GVariant** value) {
+  g_autofree const gchar* key = fl_settings_portal_format_key(setting);
+  *value = g_variant_dict_lookup_value(self->values, key, setting->type);
+  return *value != nullptr;
+}
+
+static void fl_settings_portal_set_value(FlSettingsPortal* self,
+                                         const FlSetting* setting,
+                                         GVariant* value) {
+  g_autofree const gchar* key = fl_settings_portal_format_key(setting);
+
+  // ignore redundant changes from multiple XDG desktop portal backends
+  g_autoptr(GVariant) old_value =
+      g_variant_dict_lookup_value(self->values, key, nullptr);
+  if (old_value != nullptr && value != nullptr &&
+      g_variant_equal(old_value, value)) {
+    return;
+  }
+
+  g_variant_dict_insert_value(self->values, key, value);
+  fl_settings_emit_changed(FL_SETTINGS(self));
+}
+
+static FlClockFormat fl_settings_portal_get_clock_format(FlSettings* settings) {
+  FlSettingsPortal* self = FL_SETTINGS_PORTAL(settings);
+
+  FlClockFormat clock_format = FL_CLOCK_FORMAT_24H;
+
+  g_autoptr(GVariant) value = nullptr;
+  if (fl_settings_portal_get_value(self, &kClockFormat, &value)) {
+    const gchar* clock_format_str = g_variant_get_string(value, nullptr);
+    if (g_strcmp0(clock_format_str, kClockFormat12Hour) == 0) {
+      clock_format = FL_CLOCK_FORMAT_12H;
+    }
+  }
+
+  return clock_format;
+}
+
+static FlColorScheme fl_settings_portal_get_color_scheme(FlSettings* settings) {
+  FlSettingsPortal* self = FL_SETTINGS_PORTAL(settings);
+
+  FlColorScheme color_scheme = FL_COLOR_SCHEME_LIGHT;
+
+  g_autoptr(GVariant) value = nullptr;
+  if (fl_settings_portal_get_value(self, &kColorScheme, &value)) {
+    if (g_variant_get_uint32(value) == PREFER_DARK) {
+      color_scheme = FL_COLOR_SCHEME_DARK;
+    }
+  }
+
+  return color_scheme;
+}
+
+static gdouble fl_settings_portal_get_text_scaling_factor(
+    FlSettings* settings) {
+  FlSettingsPortal* self = FL_SETTINGS_PORTAL(settings);
+
+  gdouble scaling_factor = 1.0;
+
+  g_autoptr(GVariant) value = nullptr;
+  if (fl_settings_portal_get_value(self, &kTextScalingFactor, &value)) {
+    scaling_factor = g_variant_get_double(value);
+  }
+
+  return scaling_factor;
+}
+
+static void fl_settings_portal_dispose(GObject* object) {
+  FlSettingsPortal* self = FL_SETTINGS_PORTAL(object);
+
+  g_clear_object(&self->dbus_proxy);
+  g_clear_pointer(&self->values, g_variant_dict_unref);
+
+  G_OBJECT_CLASS(fl_settings_portal_parent_class)->dispose(object);
+}
+
+static void fl_settings_portal_class_init(FlSettingsPortalClass* klass) {
+  GObjectClass* object_class = G_OBJECT_CLASS(klass);
+  object_class->dispose = fl_settings_portal_dispose;
+}
+
+static void fl_settings_portal_iface_init(FlSettingsInterface* iface) {
+  iface->get_clock_format = fl_settings_portal_get_clock_format;
+  iface->get_color_scheme = fl_settings_portal_get_color_scheme;
+  iface->get_text_scaling_factor = fl_settings_portal_get_text_scaling_factor;
+}
+
+static void fl_settings_portal_init(FlSettingsPortal* self) {}
+
+FlSettingsPortal* fl_settings_portal_new(GVariantDict* values) {
+  FlSettingsPortal* portal =
+      FL_SETTINGS_PORTAL(g_object_new(fl_settings_portal_get_type(), nullptr));
+  portal->values =
+      values ? g_variant_dict_ref(values) : g_variant_dict_new(nullptr);
+  return portal;
+}
+
+// Based on
+// https://gitlab.gnome.org/GNOME/Initiatives/-/wikis/Dark-Style-Preference#other
+static gboolean settings_portal_read(GDBusProxy* proxy,
+                                     const gchar* ns,
+                                     const gchar* key,
+                                     GVariant** out) {
+  g_autoptr(GError) error = nullptr;
+  g_autoptr(GVariant) value =
+      g_dbus_proxy_call_sync(proxy, "Read", g_variant_new("(ss)", ns, key),
+                             G_DBUS_CALL_FLAGS_NONE, G_MAXINT, nullptr, &error);
+
+  if (error) {
+    if (error->domain == G_DBUS_ERROR &&
+        error->code == G_DBUS_ERROR_SERVICE_UNKNOWN) {
+      g_debug("XDG desktop portal unavailable: %s", error->message);
+      return false;
+    }
+
+    if (error->domain == G_DBUS_ERROR &&
+        error->code == G_DBUS_ERROR_UNKNOWN_METHOD) {
+      g_debug("XDG desktop portal settings unavailable: %s", error->message);
+      return false;
+    }
+
+    g_critical("Failed to read XDG desktop portal settings: %s",
+               error->message);
+    return false;
+  }
+
+  g_autoptr(GVariant) child = nullptr;
+  g_variant_get(value, "(v)", &child);
+  g_variant_get(child, "v", out);
+
+  return true;
+}
+
+static void settings_portal_changed_cb(GDBusProxy* proxy,
+                                       const char* sender_name,
+                                       const char* signal_name,
+                                       GVariant* parameters,
+                                       gpointer user_data) {
+  FlSettingsPortal* portal = FL_SETTINGS_PORTAL(user_data);
+  if (g_strcmp0(signal_name, "SettingChanged")) {
+    return;
+  }
+
+  FlSetting setting;
+  g_autoptr(GVariant) value = nullptr;
+  g_variant_get(parameters, "(&s&sv)", &setting.ns, &setting.key, &value);
+  fl_settings_portal_set_value(portal, &setting, value);
+}
+
+gboolean fl_settings_portal_start(FlSettingsPortal* self) {
+  g_return_val_if_fail(FL_IS_SETTINGS_PORTAL(self), false);
+  g_return_val_if_fail(self->dbus_proxy == nullptr, false);
+
+  g_autoptr(GError) error = nullptr;
+
+  self->dbus_proxy = g_dbus_proxy_new_for_bus_sync(
+      G_BUS_TYPE_SESSION, G_DBUS_PROXY_FLAGS_NONE, nullptr, kPortalName,
+      kPortalPath, pPortalSettings, nullptr, &error);
+
+  if (error != nullptr) {
+    g_debug("XDG desktop portal settings unavailable: %s", error->message);
+    return false;
+  }
+
+  for (const FlSetting setting : all_settings) {
+    g_autoptr(GVariant) value = nullptr;
+    if (settings_portal_read(self->dbus_proxy, setting.ns, setting.key,
+                             &value)) {
+      fl_settings_portal_set_value(self, &setting, value);
+    }
+  }
+
+  g_signal_connect_object(self->dbus_proxy, "g-signal",
+                          G_CALLBACK(settings_portal_changed_cb), self,
+                          GConnectFlags(0));
+
+  return true;
+}
diff --git a/shell/platform/linux/fl_settings_portal.h b/shell/platform/linux/fl_settings_portal.h
@@ -0,0 +1,46 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_SHELL_PLATFORM_LINUX_FL_SETTINGS_PORTAL_H_
+#define FLUTTER_SHELL_PLATFORM_LINUX_FL_SETTINGS_PORTAL_H_
+
+#include "flutter/shell/platform/linux/fl_settings.h"
+
+G_BEGIN_DECLS
+
+G_DECLARE_FINAL_TYPE(FlSettingsPortal,
+                     fl_settings_portal,
+                     FL,
+                     SETTINGS_PORTAL,
+                     GObject);
+
+/**
+ * FlSettingsPortal:
+ * #FlSettingsPortal reads settings from the XDG desktop portal.
+ */
+
+/**
+ * fl_settings_portal_new:
+ * @values: (nullable): a #GVariantDict with values for testing.
+ *
+ * Creates a new settings portal instance.
+ *
+ * Returns: a new #FlSettingsPortal.
+ */
+FlSettingsPortal* fl_settings_portal_new(GVariantDict* values);
+
+/**
+ * fl_settings_portal_start:
+ * @portal: an #FlSettingsPortal.
+ *
+ * Reads the current settings and starts monitoring for changes in the desktop
+ * portal settings.
+ *
+ * Returns: %TRUE on success, or %FALSE if the portal is not available.
+ */
+gboolean fl_settings_portal_start(FlSettingsPortal* portal);
+
+G_END_DECLS
+
+#endif  // FLUTTER_SHELL_PLATFORM_LINUX_FL_SETTINGS_PORTAL_H_
diff --git a/shell/platform/linux/fl_settings_portal_test.cc b/shell/platform/linux/fl_settings_portal_test.cc
