Implements method PlatformDispatcher.getInitialArguments

Author: ColdPaleLight

lib/ui/platform_dispatcher.dart

@@ -569,6 +569,13 @@ class PlatformDispatcher {
   /// platform channel may be used.
   ByteData? getPersistentIsolateData() native 'PlatformConfiguration_getPersistentIsolateData';
 
+  /// Get structured data provided by embedder from dart entrypoint args. it can be passed by
+  /// `FlutterEngineGroup` when creating the engine.
+  dynamic getInitialArguments({required List<String> rawArgs}) {
+    if (rawArgs.isEmpty) return null;
+    return json.decode(rawArgs[0]);
+  }
+
   /// Requests that, at the next appropriate opportunity, the [onBeginFrame] and
   /// [onDrawFrame] callbacks be invoked.
   ///

shell/common/fixtures/shell_test.dart

@@ -231,10 +231,18 @@ void notifyNativeWhenEngineSpawn(bool success) native 'NotifyNativeWhenEngineSpa
 
 @pragma('vm:entry-point')
 void canRecieveArgumentsWhenEngineRun(List<String> args) {
-  notifyNativeWhenEngineRun(args.length == 1 && args[0] == 'arg1');
+  final dynamic initialArguments = PlatformDispatcher.instance.getInitialArguments(rawArgs: args);
+  notifyNativeWhenEngineRun(initialArguments['foo'] == 'arg1' && initialArguments['bar'] == 'arg2');
 }
 
 @pragma('vm:entry-point')
 void canRecieveArgumentsWhenEngineSpawn(List<String> args) {
-  notifyNativeWhenEngineSpawn(args.length == 1 && args[0] == 'arg2');
+  final dynamic initialArguments = PlatformDispatcher.instance.getInitialArguments(rawArgs: args);
+  notifyNativeWhenEngineSpawn(initialArguments[0] == 'arg1' && initialArguments[1] == 'arg2');
+}
+
+@pragma('vm:entry-point')
+void canRecieveEmptyArguments(List<String> args) {
+  final dynamic initialArguments = PlatformDispatcher.instance.getInitialArguments(rawArgs: args);
+  notifyNativeWhenEngineRun(args.isEmpty && initialArguments == null);
 }

shell/common/shell_unittests.cc

@@ -2836,13 +2836,14 @@ TEST_F(ShellTest, SpawnWithDartEntrypointArgs) {
   auto configuration = RunConfiguration::InferFromSettings(settings);
   ASSERT_TRUE(configuration.IsValid());
   configuration.SetEntrypoint("canRecieveArgumentsWhenEngineRun");
-  const std::vector<std::string> entrypoint_args{"arg1"};
+  const std::vector<std::string> entrypoint_args{
+      "{\"foo\":\"arg1\",\"bar\":\"arg2\"}"};
   configuration.SetEntrypointArgs(entrypoint_args);
 
   auto second_configuration = RunConfiguration::InferFromSettings(settings);
   ASSERT_TRUE(second_configuration.IsValid());
   second_configuration.SetEntrypoint("canRecieveArgumentsWhenEngineSpawn");
-  const std::vector<std::string> second_entrypoint_args{"arg2"};
+  const std::vector<std::string> second_entrypoint_args{"[\"arg1\",\"arg2\"]"};
   second_configuration.SetEntrypointArgs(second_entrypoint_args);
 
   const std::string initial_route("/foo");
@@ -2935,6 +2936,36 @@ TEST_F(ShellTest, SpawnWithDartEntrypointArgs) {
   ASSERT_FALSE(DartVMRef::IsInstanceRunning());
 }
 
+TEST_F(ShellTest, CanRecieveEmptyArguments) {
+  auto settings = CreateSettingsForFixture();
+  auto shell = CreateShell(settings);
+  ASSERT_TRUE(ValidateShell(shell.get()));
+
+  auto configuration = RunConfiguration::InferFromSettings(settings);
+  ASSERT_TRUE(configuration.IsValid());
+  configuration.SetEntrypoint("canRecieveEmptyArguments");
+
+  fml::AutoResetWaitableEvent main_latch;
+  std::string last_entry_point;
+
+  AddNativeCallback("NotifyNativeWhenEngineRun",
+                    CREATE_NATIVE_ENTRY(([&](Dart_NativeArguments args) {
+                      ASSERT_TRUE(tonic::DartConverter<bool>::FromDart(
+                          Dart_GetNativeArgument(args, 0)));
+                      last_entry_point =
+                          shell->GetEngine()->GetLastEntrypoint();
+                      main_latch.Signal();
+                    })));
+
+  RunEngine(shell.get(), std::move(configuration));
+  main_latch.Wait();
+  ASSERT_TRUE(DartVMRef::IsInstanceRunning());
+  ASSERT_EQ("canRecieveEmptyArguments", last_entry_point);
+
+  DestroyShell(std::move(shell));
+  ASSERT_FALSE(DartVMRef::IsInstanceRunning());
+}
+
 TEST_F(ShellTest, UpdateAssetResolverByTypeReplaces) {
   ASSERT_FALSE(DartVMRef::IsInstanceRunning());
   Settings settings = CreateSettingsForFixture();