Switch Linux embedding to proc table embedder API (flutter#22280)

Switches the Linux embedding from the standard C API to the new proctable version, to allow for unit testing of the embedding layer separately from the embedder APIs implementation.

Author: stuartmorgan-g

shell/platform/linux/BUILD.gn

@@ -119,7 +119,10 @@ source_set("flutter_linux_sources") {
   ]
 
   # Set flag to stop headers being directly included (library users should not do this)
-  defines = [ "FLUTTER_LINUX_COMPILATION" ]
+  defines = [
+    "FLUTTER_LINUX_COMPILATION",
+    "FLUTTER_ENGINE_NO_PROTOTYPES",
+  ]
 
   deps = [
     "//flutter/shell/platform/common/cpp:common_cpp_input",
@@ -138,6 +141,8 @@ source_set("flutter_linux") {
     "//third_party/khronos:khronos_headers",
   ]
 
+  defines = [ "FLUTTER_ENGINE_NO_PROTOTYPES" ]
+
   public_deps = [ ":flutter_linux_sources" ]
 
   deps = [ "//flutter/shell/platform/embedder:embedder_as_internal_library" ]
@@ -182,14 +187,20 @@ executable("flutter_linux_unittests") {
     "//flutter/shell/platform/linux/config:x11",
   ]
 
-  # Set flag to allow public headers to be directly included (library users should not do this)
-  defines = [ "FLUTTER_LINUX_COMPILATION" ]
+  defines = [
+    "FLUTTER_ENGINE_NO_PROTOTYPES",
+
+    # Set flag to allow public headers to be directly included
+    # (library users should not do this)
+    "FLUTTER_LINUX_COMPILATION",
+  ]
 
   deps = [
     ":flutter_linux_fixtures",
     ":flutter_linux_sources",
     "//flutter/runtime:libdart",
     "//flutter/shell/platform/embedder:embedder_headers",
+    "//flutter/shell/platform/embedder:embedder_test_utils",
     "//flutter/testing",
   ]
 }

shell/platform/linux/fl_basic_message_channel_test.cc

@@ -5,13 +5,54 @@
 // Included first as it collides with the X11 headers.
 #include "gtest/gtest.h"
 
+#include "flutter/shell/platform/linux/public/flutter_linux/fl_basic_message_channel.h"
+
+#include "flutter/shell/platform/embedder/embedder.h"
+#include "flutter/shell/platform/embedder/test_utils/proc_table_replacement.h"
 #include "flutter/shell/platform/linux/fl_binary_messenger_private.h"
 #include "flutter/shell/platform/linux/fl_engine_private.h"
-#include "flutter/shell/platform/linux/public/flutter_linux/fl_basic_message_channel.h"
+#include "flutter/shell/platform/linux/public/flutter_linux/fl_message_codec.h"
 #include "flutter/shell/platform/linux/public/flutter_linux/fl_standard_message_codec.h"
 #include "flutter/shell/platform/linux/testing/fl_test.h"
 #include "flutter/shell/platform/linux/testing/mock_renderer.h"
 
+// Checks sending a message without a reponse works.
+TEST(FlBasicMessageChannelTest, SendMessageWithoutResponse) {
+  g_autoptr(GMainLoop) loop = g_main_loop_new(nullptr, 0);
+
+  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, "test");
+        EXPECT_EQ(message->response_handle, nullptr);
+
+        g_autoptr(GBytes) message_bytes =
+            g_bytes_new(message->message, message->message_size);
+        g_autoptr(FlStandardMessageCodec) codec =
+            fl_standard_message_codec_new();
+        FlValue* message_value = fl_message_codec_decode_message(
+            FL_MESSAGE_CODEC(codec), message_bytes, nullptr);
+        EXPECT_EQ(fl_value_get_type(message_value), FL_VALUE_TYPE_STRING);
+        EXPECT_STREQ(fl_value_get_string(message_value), "Hello World!");
+
+        return kSuccess;
+      }));
+
+  FlBinaryMessenger* messenger = fl_binary_messenger_new(engine);
+  g_autoptr(FlStandardMessageCodec) codec = fl_standard_message_codec_new();
+  g_autoptr(FlBasicMessageChannel) channel =
+      fl_basic_message_channel_new(messenger, "test", FL_MESSAGE_CODEC(codec));
+  g_autoptr(FlValue) message = fl_value_new_string("Hello World!");
+  fl_basic_message_channel_send(channel, message, nullptr, nullptr, loop);
+
+  EXPECT_TRUE(called);
+}
+
 // Called when the message response is received in the SendMessage test.
 static void echo_response_cb(GObject* object,
                              GAsyncResult* result,
@@ -28,8 +69,8 @@ static void echo_response_cb(GObject* object,
   g_main_loop_quit(static_cast<GMainLoop*>(user_data));
 }
 
-// Checks sending a message works.
-TEST(FlBasicMessageChannelTest, SendMessage) {
+// Checks sending a message with a response works.
+TEST(FlBasicMessageChannelTest, SendMessageWithResponse) {
   g_autoptr(GMainLoop) loop = g_main_loop_new(nullptr, 0);
 
   g_autoptr(FlEngine) engine = make_mock_engine();

shell/platform/linux/fl_engine.cc

@@ -32,6 +32,7 @@ struct _FlEngine {
   FlBinaryMessenger* binary_messenger;
   FlutterEngineAOTData aot_data;
   FLUTTER_API_SYMBOL(FlutterEngine) engine;
+  FlutterEngineProcTable embedder_api;
 
   // Function to call when a platform message is received.
   FlEnginePlatformMessageHandler platform_message_handler;
@@ -127,7 +128,7 @@ static void setup_locales(FlEngine* self) {
   }
   FlutterLocale** locales =
       reinterpret_cast<FlutterLocale**>(locales_array->pdata);
-  FlutterEngineResult result = FlutterEngineUpdateLocales(
+  FlutterEngineResult result = self->embedder_api.UpdateLocales(
       self->engine, const_cast<const FlutterLocale**>(locales),
       locales_array->len);
   if (result != kSuccess) {
@@ -143,7 +144,7 @@ static gboolean flutter_source_dispatch(GSource* source,
   FlEngine* self = fl_source->engine;
 
   FlutterEngineResult result =
-      FlutterEngineRunTask(self->engine, &fl_source->task);
+      self->embedder_api.RunTask(self->engine, &fl_source->task);
   if (result != kSuccess) {
     g_warning("Failed to run Flutter task\n");
   }
@@ -302,12 +303,12 @@ static void fl_engine_dispose(GObject* object) {
   FlEngine* self = FL_ENGINE(object);
 
   if (self->engine != nullptr) {
-    FlutterEngineShutdown(self->engine);
+    self->embedder_api.Shutdown(self->engine);
     self->engine = nullptr;
   }
 
   if (self->aot_data != nullptr) {
-    FlutterEngineCollectAOTData(self->aot_data);
+    self->embedder_api.CollectAOTData(self->aot_data);
     self->aot_data = nullptr;
   }
 
@@ -332,6 +333,9 @@ static void fl_engine_class_init(FlEngineClass* klass) {
 static void fl_engine_init(FlEngine* self) {
   self->thread = g_thread_self();
 
+  self->embedder_api.struct_size = sizeof(FlutterEngineProcTable);
+  FlutterEngineGetProcAddresses(&self->embedder_api);
+
   self->binary_messenger = fl_binary_messenger_new(self);
 }
 
@@ -400,27 +404,28 @@ gboolean fl_engine_start(FlEngine* self, GError** error) {
   args.dart_entrypoint_argv =
       reinterpret_cast<const char* const*>(dart_entrypoint_args);
 
-  if (FlutterEngineRunsAOTCompiledDartCode()) {
+  if (self->embedder_api.RunsAOTCompiledDartCode()) {
     FlutterEngineAOTDataSource source = {};
     source.type = kFlutterEngineAOTDataSourceTypeElfPath;
     source.elf_path = fl_dart_project_get_aot_library_path(self->project);
-    if (FlutterEngineCreateAOTData(&source, &self->aot_data) != kSuccess) {
+    if (self->embedder_api.CreateAOTData(&source, &self->aot_data) !=
+        kSuccess) {
       g_set_error(error, fl_engine_error_quark(), FL_ENGINE_ERROR_FAILED,
                   "Failed to create AOT data");
       return FALSE;
     }
     args.aot_data = self->aot_data;
   }
 
-  FlutterEngineResult result = FlutterEngineInitialize(
+  FlutterEngineResult result = self->embedder_api.Initialize(
       FLUTTER_ENGINE_VERSION, &config, &args, self, &self->engine);
   if (result != kSuccess) {
     g_set_error(error, fl_engine_error_quark(), FL_ENGINE_ERROR_FAILED,
                 "Failed to initialize Flutter engine");
     return FALSE;
   }
 
-  result = FlutterEngineRunInitialized(self->engine);
+  result = self->embedder_api.RunInitialized(self->engine);
   if (result != kSuccess) {
     g_set_error(error, fl_engine_error_quark(), FL_ENGINE_ERROR_FAILED,
                 "Failed to run Flutter engine");
@@ -432,6 +437,10 @@ gboolean fl_engine_start(FlEngine* self, GError** error) {
   return TRUE;
 }
 
+FlutterEngineProcTable* fl_engine_get_embedder_api(FlEngine* self) {
+  return &(self->embedder_api);
+}
+
 void fl_engine_set_platform_message_handler(
     FlEngine* self,
     FlEnginePlatformMessageHandler handler,
@@ -470,7 +479,7 @@ gboolean fl_engine_send_platform_message_response(
     data =
         static_cast<const uint8_t*>(g_bytes_get_data(response, &data_length));
   }
-  FlutterEngineResult result = FlutterEngineSendPlatformMessageResponse(
+  FlutterEngineResult result = self->embedder_api.SendPlatformMessageResponse(
       self->engine, handle, data, data_length);
 
   if (result != kSuccess) {
@@ -501,9 +510,10 @@ void fl_engine_send_platform_message(FlEngine* self,
       return;
     }
 
-    FlutterEngineResult result = FlutterPlatformMessageCreateResponseHandle(
-        self->engine, fl_engine_platform_message_response_cb, task,
-        &response_handle);
+    FlutterEngineResult result =
+        self->embedder_api.PlatformMessageCreateResponseHandle(
+            self->engine, fl_engine_platform_message_response_cb, task,
+            &response_handle);
     if (result != kSuccess) {
       g_task_return_new_error(task, fl_engine_error_quark(),
                               FL_ENGINE_ERROR_FAILED,
@@ -525,7 +535,7 @@ void fl_engine_send_platform_message(FlEngine* self,
   fl_message.message_size = message != nullptr ? g_bytes_get_size(message) : 0;
   fl_message.response_handle = response_handle;
   FlutterEngineResult result =
-      FlutterEngineSendPlatformMessage(self->engine, &fl_message);
+      self->embedder_api.SendPlatformMessage(self->engine, &fl_message);
 
   if (result != kSuccess && task != nullptr) {
     g_task_return_new_error(task, fl_engine_error_quark(),
@@ -535,7 +545,8 @@ void fl_engine_send_platform_message(FlEngine* self,
   }
 
   if (response_handle != nullptr) {
-    FlutterPlatformMessageReleaseResponseHandle(self->engine, response_handle);
+    self->embedder_api.PlatformMessageReleaseResponseHandle(self->engine,
+                                                            response_handle);
   }
 }
 
@@ -563,7 +574,7 @@ void fl_engine_send_window_metrics_event(FlEngine* self,
   event.width = width;
   event.height = height;
   event.pixel_ratio = pixel_ratio;
-  FlutterEngineSendWindowMetricsEvent(self->engine, &event);
+  self->embedder_api.SendWindowMetricsEvent(self->engine, &event);
 }
 
 void fl_engine_send_mouse_pointer_event(FlEngine* self,
@@ -593,7 +604,7 @@ void fl_engine_send_mouse_pointer_event(FlEngine* self,
   fl_event.scroll_delta_y = scroll_delta_y;
   fl_event.device_kind = kFlutterPointerDeviceKindMouse;
   fl_event.buttons = buttons;
-  FlutterEngineSendPointerEvent(self->engine, &fl_event, 1);
+  self->embedder_api.SendPointerEvent(self->engine, &fl_event, 1);
 }
 
 G_MODULE_EXPORT FlBinaryMessenger* fl_engine_get_binary_messenger(

shell/platform/linux/fl_engine_private.h

@@ -55,6 +55,16 @@ typedef gboolean (*FlEnginePlatformMessageHandler)(
  */
 FlEngine* fl_engine_new(FlDartProject* project, FlRenderer* renderer);
 
+/**
+ * fl_engine_get_embedder_api:
+ * @engine: an #FlEngine.
+ *
+ * Gets the embedder API proc table, allowing modificiations for unit testing.
+ *
+ * Returns: a mutable pointer to the embedder API proc table.
+ */
+FlutterEngineProcTable* fl_engine_get_embedder_api(FlEngine* engine);
+
 /**
  * fl_engine_set_platform_message_handler:
  * @engine: an #FlEngine.