Implement settings channel for the Linux shell (flutter/engine#22486)

Implement settings channel for the Linux shell

Fixes https://github.com/flutter/flutter/issues/65591

engine/src/flutter/ci/licenses_golden/licenses_flutter

@@ -2134,6 +2134,8 @@ FILE: ../../../flutter/shell/platform/linux/fl_renderer_wayland.cc
 FILE: ../../../flutter/shell/platform/linux/fl_renderer_wayland.h
 FILE: ../../../flutter/shell/platform/linux/fl_renderer_x11.cc
 FILE: ../../../flutter/shell/platform/linux/fl_renderer_x11.h
+FILE: ../../../flutter/shell/platform/linux/fl_settings_plugin.cc
+FILE: ../../../flutter/shell/platform/linux/fl_settings_plugin.h
 FILE: ../../../flutter/shell/platform/linux/fl_standard_message_codec.cc
 FILE: ../../../flutter/shell/platform/linux/fl_standard_message_codec_private.h
 FILE: ../../../flutter/shell/platform/linux/fl_standard_message_codec_test.cc

engine/src/flutter/shell/platform/linux/BUILD.gn

@@ -110,6 +110,7 @@ source_set("flutter_linux_sources") {
     "fl_renderer_headless.cc",
     "fl_renderer_wayland.cc",
     "fl_renderer_x11.cc",
+    "fl_settings_plugin.cc",
     "fl_standard_message_codec.cc",
     "fl_standard_method_codec.cc",
     "fl_string_codec.cc",

engine/src/flutter/shell/platform/linux/fl_basic_message_channel_test.cc

@@ -24,11 +24,17 @@ TEST(FlBasicMessageChannelTest, SendMessageWithoutResponse) {
   FlutterEngineProcTable* embedder_api = fl_engine_get_embedder_api(engine);
 
   bool called = false;
+  FlutterEngineSendPlatformMessageFnPtr old_handler =
+      embedder_api->SendPlatformMessage;
   embedder_api->SendPlatformMessage = MOCK_ENGINE_PROC(
       SendPlatformMessage,
-      ([&called](auto engine, const FlutterPlatformMessage* message) {
+      ([&called, old_handler](auto engine,
+                              const FlutterPlatformMessage* message) {
+        if (strcmp(message->channel, "test") != 0) {
+          return old_handler(engine, message);
+        }
+
         called = true;
-        EXPECT_STREQ(message->channel, "test");
         EXPECT_EQ(message->response_handle, nullptr);
 
         g_autoptr(GBytes) message_bytes =

engine/src/flutter/shell/platform/linux/fl_engine.cc

@@ -14,6 +14,7 @@
 #include "flutter/shell/platform/linux/fl_plugin_registrar_private.h"
 #include "flutter/shell/platform/linux/fl_renderer.h"
 #include "flutter/shell/platform/linux/fl_renderer_headless.h"
+#include "flutter/shell/platform/linux/fl_settings_plugin.h"
 #include "flutter/shell/platform/linux/public/flutter_linux/fl_plugin_registry.h"
 
 static constexpr int kMicrosecondsPerNanosecond = 1000;
@@ -30,6 +31,7 @@ struct _FlEngine {
   FlDartProject* project;
   FlRenderer* renderer;
   FlBinaryMessenger* binary_messenger;
+  FlSettingsPlugin* settings_plugin;
   FlutterEngineAOTData aot_data;
   FLUTTER_API_SYMBOL(FlutterEngine) engine;
   FlutterEngineProcTable embedder_api;
@@ -315,6 +317,7 @@ static void fl_engine_dispose(GObject* object) {
   g_clear_object(&self->project);
   g_clear_object(&self->renderer);
   g_clear_object(&self->binary_messenger);
+  g_clear_object(&self->settings_plugin);
 
   if (self->platform_message_handler_destroy_notify) {
     self->platform_message_handler_destroy_notify(
@@ -434,6 +437,9 @@ gboolean fl_engine_start(FlEngine* self, GError** error) {
 
   setup_locales(self);
 
+  self->settings_plugin = fl_settings_plugin_new(self->binary_messenger);
+  fl_settings_plugin_start(self->settings_plugin);
+
   return TRUE;
 }
 

engine/src/flutter/shell/platform/linux/fl_engine_test.cc

@@ -8,6 +8,7 @@
 #include "flutter/shell/platform/embedder/test_utils/proc_table_replacement.h"
 #include "flutter/shell/platform/linux/fl_engine_private.h"
 #include "flutter/shell/platform/linux/public/flutter_linux/fl_engine.h"
+#include "flutter/shell/platform/linux/public/flutter_linux/fl_json_message_codec.h"
 #include "flutter/shell/platform/linux/testing/fl_test.h"
 
 // Checks sending window metrics events works.
@@ -76,12 +77,18 @@ TEST(FlEngineTest, PlatformMessage) {
   FlutterEngineProcTable* embedder_api = fl_engine_get_embedder_api(engine);
 
   bool called = false;
+  FlutterEngineSendPlatformMessageFnPtr old_handler =
+      embedder_api->SendPlatformMessage;
   embedder_api->SendPlatformMessage = MOCK_ENGINE_PROC(
       SendPlatformMessage,
-      ([&called](auto engine, const FlutterPlatformMessage* message) {
+      ([&called, old_handler](auto engine,
+                              const FlutterPlatformMessage* message) {
+        if (strcmp(message->channel, "test") != 0) {
+          return old_handler(engine, message);
+        }
+
         called = true;
 
-        EXPECT_STREQ(message->channel, "test");
         EXPECT_EQ(message->message_size, static_cast<size_t>(4));
         EXPECT_EQ(message->message[0], 't');
         EXPECT_EQ(message->message[1], 'e');
@@ -137,3 +144,52 @@ TEST(FlEngineTest, PlatformMessageResponse) {
 
   EXPECT_TRUE(called);
 }
+
+// Checks settings plugin sends settings on startup.
+TEST(FlEngineTest, SettingsPlugin) {
+  g_autoptr(FlEngine) engine = make_mock_engine();
+  FlutterEngineProcTable* embedder_api = fl_engine_get_embedder_api(engine);
+
+  bool called = false;
+  embedder_api->SendPlatformMessage = MOCK_ENGINE_PROC(
+      SendPlatformMessage,
+      ([&called](auto engine, const FlutterPlatformMessage* message) {
+        called = true;
+
+        EXPECT_STREQ(message->channel, "flutter/settings");
+
+        g_autoptr(FlJsonMessageCodec) codec = fl_json_message_codec_new();
+        g_autoptr(GBytes) data =
+            g_bytes_new(message->message, message->message_size);
+        g_autoptr(GError) error = nullptr;
+        g_autoptr(FlValue) settings = fl_message_codec_decode_message(
+            FL_MESSAGE_CODEC(codec), data, &error);
+        EXPECT_NE(settings, nullptr);
+        EXPECT_EQ(error, nullptr);
+        g_printerr("%s\n", fl_value_to_string(settings));
+
+        g_autoptr(FlValue) text_scale_factor =
+            fl_value_lookup_string(settings, "textScaleFactor");
+        EXPECT_NE(text_scale_factor, nullptr);
+        EXPECT_EQ(fl_value_get_type(text_scale_factor), FL_VALUE_TYPE_FLOAT);
+
+        g_autoptr(FlValue) always_use_24hr_format =
+            fl_value_lookup_string(settings, "alwaysUse24HourFormat");
+        EXPECT_NE(always_use_24hr_format, nullptr);
+        EXPECT_EQ(fl_value_get_type(always_use_24hr_format),
+                  FL_VALUE_TYPE_BOOL);
+
+        g_autoptr(FlValue) platform_brightness =
+            fl_value_lookup_string(settings, "platformBrightness");
+        EXPECT_NE(platform_brightness, nullptr);
+        EXPECT_EQ(fl_value_get_type(platform_brightness), FL_VALUE_TYPE_STRING);
+
+        return kSuccess;
+      }));
+
+  g_autoptr(GError) error = nullptr;
+  EXPECT_TRUE(fl_engine_start(engine, &error));
+  EXPECT_EQ(error, nullptr);
+
+  EXPECT_TRUE(called);
+}

engine/src/flutter/shell/platform/linux/fl_settings_plugin.cc

@@ -0,0 +1,120 @@
+// 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_plugin.h"
+
+#include <cstring>
+
+#include "flutter/shell/platform/linux/public/flutter_linux/fl_basic_message_channel.h"
+#include "flutter/shell/platform/linux/public/flutter_linux/fl_json_message_codec.h"
+
+static constexpr char kChannelName[] = "flutter/settings";
+static constexpr char kTextScaleFactorKey[] = "textScaleFactor";
+static constexpr char kAlwaysUse24HourFormatKey[] = "alwaysUse24HourFormat";
+static constexpr char kPlatformBrightnessKey[] = "platformBrightness";
+static constexpr char kPlatformBrightnessLight[] = "light";
+static constexpr char kPlatformBrightnessDark[] = "dark";
+
+static constexpr char kDesktopInterfaceSchema[] = "org.gnome.desktop.interface";
+static constexpr char kDesktopGtkThemeKey[] = "gtk-theme";
+static constexpr char kDesktopTextScalingFactorKey[] = "text-scaling-factor";
+static constexpr char kDesktopClockFormatKey[] = "clock-format";
+static constexpr char kClockFormat24Hour[] = "24h";
+
+struct _FlSettingsPlugin {
+  GObject parent_instance;
+
+  FlBasicMessageChannel* channel;
+
+  GSettings* interface_settings;
+};
+
+G_DEFINE_TYPE(FlSettingsPlugin, fl_settings_plugin, G_TYPE_OBJECT)
+
+// Sends the current settings to the Flutter engine.
+static void update_settings(FlSettingsPlugin* self) {
+  gdouble scaling_factor = 1.0;
+  gboolean always_use_24hr = FALSE;
+  const gchar* platform_brightness = kPlatformBrightnessLight;
+
+  if (self->interface_settings != nullptr) {
+    scaling_factor = g_settings_get_double(self->interface_settings,
+                                           kDesktopTextScalingFactorKey);
+    g_autofree gchar* clock_format =
+        g_settings_get_string(self->interface_settings, kDesktopClockFormatKey);
+    always_use_24hr = g_strcmp0(clock_format, kClockFormat24Hour) == 0;
+
+    // GTK doesn't have a specific flag for dark themes, so we have some
+    // hard-coded themes for Ubuntu (Yaru) and GNOME (Adwaita).
+    g_autofree gchar* gtk_theme =
+        g_settings_get_string(self->interface_settings, kDesktopGtkThemeKey);
+    if (g_strcmp0(gtk_theme, "Yaru-dark") == 0 ||
+        g_strcmp0(gtk_theme, "Adwaita-dark") == 0) {
+      platform_brightness = kPlatformBrightnessDark;
+    }
+  }
+
+  g_autoptr(FlValue) message = fl_value_new_map();
+  fl_value_set_string_take(message, kTextScaleFactorKey,
+                           fl_value_new_float(scaling_factor));
+  fl_value_set_string_take(message, kAlwaysUse24HourFormatKey,
+                           fl_value_new_bool(always_use_24hr));
+  fl_value_set_string_take(message, kPlatformBrightnessKey,
+                           fl_value_new_string(platform_brightness));
+  fl_basic_message_channel_send(self->channel, message, nullptr, nullptr,
+                                nullptr);
+}
+
+static void fl_settings_plugin_dispose(GObject* object) {
+  FlSettingsPlugin* self = FL_SETTINGS_PLUGIN(object);
+
+  g_clear_object(&self->channel);
+  g_clear_object(&self->interface_settings);
+
+  G_OBJECT_CLASS(fl_settings_plugin_parent_class)->dispose(object);
+}
+
+static void fl_settings_plugin_class_init(FlSettingsPluginClass* klass) {
+  G_OBJECT_CLASS(klass)->dispose = fl_settings_plugin_dispose;
+}
+
+static void fl_settings_plugin_init(FlSettingsPlugin* self) {}
+
+FlSettingsPlugin* fl_settings_plugin_new(FlBinaryMessenger* messenger) {
+  g_return_val_if_fail(FL_IS_BINARY_MESSENGER(messenger), nullptr);
+
+  FlSettingsPlugin* self =
+      FL_SETTINGS_PLUGIN(g_object_new(fl_settings_plugin_get_type(), nullptr));
+
+  g_autoptr(FlJsonMessageCodec) codec = fl_json_message_codec_new();
+  self->channel = fl_basic_message_channel_new(messenger, kChannelName,
+                                               FL_MESSAGE_CODEC(codec));
+
+  return self;
+}
+
+void fl_settings_plugin_start(FlSettingsPlugin* self) {
+  g_return_if_fail(FL_IS_SETTINGS_PLUGIN(self));
+
+  // If we are on GNOME, get settings from GSettings.
+  GSettingsSchemaSource* source = g_settings_schema_source_get_default();
+  if (source != nullptr) {
+    g_autoptr(GSettingsSchema) schema =
+        g_settings_schema_source_lookup(source, kDesktopInterfaceSchema, FALSE);
+    if (schema != nullptr) {
+      self->interface_settings = g_settings_new_full(schema, nullptr, nullptr);
+      g_signal_connect_object(
+          self->interface_settings, "changed::text-scaling-factor",
+          G_CALLBACK(update_settings), self, G_CONNECT_SWAPPED);
+      g_signal_connect_object(self->interface_settings, "changed::clock-format",
+                              G_CALLBACK(update_settings), self,
+                              G_CONNECT_SWAPPED);
+      g_signal_connect_object(self->interface_settings, "changed::gtk-theme",
+                              G_CALLBACK(update_settings), self,
+                              G_CONNECT_SWAPPED);
+    }
+  }
+
+  update_settings(self);
+}

engine/src/flutter/shell/platform/linux/fl_settings_plugin.h

@@ -0,0 +1,45 @@
+// 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_PLUGIN_H_
+#define FLUTTER_SHELL_PLATFORM_LINUX_FL_SETTINGS_PLUGIN_H_
+
+#include "flutter/shell/platform/linux/public/flutter_linux/fl_binary_messenger.h"
+
+G_BEGIN_DECLS
+
+G_DECLARE_FINAL_TYPE(FlSettingsPlugin,
+                     fl_settings_plugin,
+                     FL,
+                     SETTINGS_PLUGIN,
+                     GObject);
+
+/**
+ * FlSettingsPlugin:
+ *
+ * #FlSettingsPlugin is a plugin that implements the Flutter user settings
+ * channel.
+ */
+
+/**
+ * fl_settings_plugin_new:
+ * @messenger: an #FlBinaryMessenger
+ *
+ * Creates a new plugin that sends user settings to the Flutter engine.
+ *
+ * Returns: a new #FlSettingsPlugin
+ */
+FlSettingsPlugin* fl_settings_plugin_new(FlBinaryMessenger* messenger);
+
+/**
+ * fl_settings_plugin_start:
+ * @self: an #FlSettingsPlugin.
+ *
+ * Sends the current settings to the engine and updates when they change.
+ */
+void fl_settings_plugin_start(FlSettingsPlugin* plugin);
+
+G_END_DECLS
+
+#endif  // FLUTTER_SHELL_PLATFORM_LINUX_FL_SETTINGS_PLUGIN_H_