Merge pull request flutter#3 from canonical/multi-window

Adds support for multiple regular windows and popups to the Windows embedder

Author: hbatagelo

lib/ui/window/pointer_data_packet_converter.cc

@@ -74,6 +74,7 @@ void PointerDataPacketConverter::ConvertPointerData(
         break;
       }
       case PointerData::Change::kAdd: {
+        states_.erase(pointer_data.device);
         FML_DCHECK(states_.find(pointer_data.device) == states_.end());
         EnsurePointerState(pointer_data);
         converted_pointers.push_back(pointer_data);
@@ -82,6 +83,8 @@ void PointerDataPacketConverter::ConvertPointerData(
       case PointerData::Change::kRemove: {
         // Makes sure we have an existing pointer
         auto iter = states_.find(pointer_data.device);
+        if (iter == states_.end())
+          break;
         FML_DCHECK(iter != states_.end());
         PointerState state = iter->second;
 

shell/platform/windows/client_wrapper/BUILD.gn

@@ -11,12 +11,18 @@ _wrapper_includes = [
   "include/flutter/flutter_engine.h",
   "include/flutter/flutter_view_controller.h",
   "include/flutter/flutter_view.h",
+  "include/flutter/flutter_win32_window.h",
+  "include/flutter/flutter_window_controller.h",
   "include/flutter/plugin_registrar_windows.h",
+  "include/flutter/win32_window.h",
 ]
 
 _wrapper_sources = [
   "flutter_engine.cc",
   "flutter_view_controller.cc",
+  "flutter_win32_window.cc",
+  "flutter_window_controller.cc",
+  "win32_window.cc",
 ]
 
 # This code will be merged into .../common/client_wrapper for client use,
@@ -40,6 +46,8 @@ source_set("client_wrapper_windows") {
     "//flutter/shell/platform/windows:flutter_windows_headers",
   ]
 
+  libs = [ "dwmapi.lib" ]
+
   configs +=
       [ "//flutter/shell/platform/common:desktop_library_implementation" ]
 
@@ -110,6 +118,9 @@ client_wrapper_file_archive_list = [
 win_client_wrapper_file_archive_list = [
   "flutter_engine.cc",
   "flutter_view_controller.cc",
+  "flutter_win32_window.cc",
+  "flutter_window_controller.cc",
+  "win32_window.cc",
 ]
 
 zip_bundle("client_wrapper_archive") {

shell/platform/windows/client_wrapper/flutter_engine.cc

@@ -63,7 +63,7 @@ bool FlutterEngine::Run(const char* entry_point) {
 }
 
 void FlutterEngine::ShutDown() {
-  if (engine_ && owns_engine_) {
+  if (engine_) {
     FlutterDesktopEngineDestroy(engine_);
   }
   engine_ = nullptr;
@@ -113,8 +113,7 @@ std::optional<LRESULT> FlutterEngine::ProcessExternalWindowMessage(
   return std::nullopt;
 }
 
-FlutterDesktopEngineRef FlutterEngine::RelinquishEngine() {
-  owns_engine_ = false;
+FlutterDesktopEngineRef FlutterEngine::engine() const {
   return engine_;
 }
 

shell/platform/windows/client_wrapper/flutter_view_controller.cc

@@ -11,10 +11,22 @@ namespace flutter {
 
 FlutterViewController::FlutterViewController(int width,
                                              int height,
-                                             const DartProject& project) {
-  engine_ = std::make_shared<FlutterEngine>(project);
-  controller_ = FlutterDesktopViewControllerCreate(width, height,
-                                                   engine_->RelinquishEngine());
+                                             const DartProject& project)
+    : FlutterViewController(width,
+                            height,
+                            std::make_shared<FlutterEngine>(project)) {}
+
+FlutterViewController::FlutterViewController(
+    int width,
+    int height,
+    std::shared_ptr<FlutterEngine> engine) {
+  FlutterDesktopViewControllerProperties properties = {};
+  properties.width = width;
+  properties.height = height;
+
+  engine_ = std::move(engine);
+  controller_ =
+      FlutterDesktopEngineCreateViewController(engine_->engine(), &properties);
   if (!controller_) {
     std::cerr << "Failed to create view controller." << std::endl;
     return;

shell/platform/windows/client_wrapper/flutter_view_controller_unittests.cc

@@ -17,10 +17,8 @@ namespace {
 class TestWindowsApi : public testing::StubFlutterWindowsApi {
  public:
   // |flutter::testing::StubFlutterWindowsApi|
-  FlutterDesktopViewControllerRef ViewControllerCreate(
-      int width,
-      int height,
-      FlutterDesktopEngineRef engine) override {
+  FlutterDesktopViewControllerRef EngineCreateViewController(
+      const FlutterDesktopViewControllerProperties* properties) override {
     return reinterpret_cast<FlutterDesktopViewControllerRef>(2);
   }
 
@@ -63,11 +61,13 @@ TEST(FlutterViewControllerTest, CreateDestroy) {
   testing::ScopedStubFlutterWindowsApi scoped_api_stub(
       std::make_unique<TestWindowsApi>());
   auto test_api = static_cast<TestWindowsApi*>(scoped_api_stub.stub());
+
+  // Create and destroy a view controller.
+  // This should also create and destroy an engine.
   { FlutterViewController controller(100, 100, project); }
+
   EXPECT_TRUE(test_api->view_controller_destroyed());
-  // Per the C API, once a view controller has taken ownership of an engine
-  // the engine destruction method should not be called.
-  EXPECT_FALSE(test_api->engine_destroyed());
+  EXPECT_TRUE(test_api->engine_destroyed());
 }
 
 TEST(FlutterViewControllerTest, GetViewId) {

shell/platform/windows/client_wrapper/flutter_win32_window.cc

@@ -0,0 +1,88 @@
+#include "include/flutter/flutter_win32_window.h"
+
+#include "include/flutter/encodable_value.h"
+#include "include/flutter/flutter_window_controller.h"
+
+#include <windows.h>
+
+namespace flutter {
+
+FlutterWin32Window::FlutterWin32Window(std::shared_ptr<FlutterEngine> engine)
+    : engine_(std::move(engine)) {}
+
+auto FlutterWin32Window::flutter_controller()
+    -> std::unique_ptr<FlutterViewController> const& {
+  return flutter_controller_;
+}
+
+bool FlutterWin32Window::OnCreate() {
+  if (!Win32Window::OnCreate()) {
+    return false;
+  }
+
+  RECT const frame = GetClientArea();
+
+  // The size here must match the window dimensions to avoid unnecessary surface
+  // creation / destruction in the startup path.
+  flutter_controller_ = std::make_unique<FlutterViewController>(
+      frame.right - frame.left, frame.bottom - frame.top, engine_);
+  // Ensure that basic setup of the controller was successful.
+  if (!flutter_controller_->view()) {
+    return false;
+  }
+
+  SetChildContent(flutter_controller_->view()->GetNativeWindow());
+
+  // TODO(loicsharma): Hide the window until the first frame is rendered.
+  // Single window apps use the engine's next frame callback to show the window.
+  // This doesn't work for multi window apps as the engine cannot have multiple
+  // next frame callbacks. If multiple windows are created, only the last one
+  // will be shown.
+  return true;
+}
+
+void FlutterWin32Window::OnDestroy() {
+  if (flutter_controller_) {
+    FlutterWindowController::instance().destroyWindow(
+        flutter_controller_->view_id(), false);
+    if (flutter_controller_) {
+      flutter_controller_ = nullptr;
+    }
+  }
+
+  Win32Window::OnDestroy();
+}
+
+LRESULT
+FlutterWin32Window::MessageHandler(HWND hwnd,
+                                   UINT const message,
+                                   WPARAM const wparam,
+                                   LPARAM const lparam) {
+  // Give Flutter, including plugins, an opportunity to handle window messages.
+  if (flutter_controller_) {
+    std::optional<LRESULT> result =
+        flutter_controller_->HandleTopLevelWindowProc(hwnd, message, wparam,
+                                                      lparam);
+    if (result) {
+      return *result;
+    }
+  }
+
+  switch (message) {
+    case WM_FONTCHANGE:
+      engine_->ReloadSystemFonts();
+      break;
+    case WM_SIZE:
+      if (flutter_controller_) {
+        FlutterWindowController::instance().sendOnWindowResized(
+            flutter_controller_->view_id());
+      }
+      break;
+    default:
+      break;
+  }
+
+  return Win32Window::MessageHandler(hwnd, message, wparam, lparam);
+}
+
+}  // namespace flutter