Refactor new editor host orchestration

new_editor/app/Host/WindowMessageDispatcher.cpp

@@ -0,0 +1,115 @@
+#include "WindowMessageDispatcher.h"
+
+#include "../Application.h"
+
+namespace XCEngine::UI::Editor::Host {
+
+namespace {
+
+constexpr UINT kDeferredRenderMessage = WM_APP + 1u;
+
+void TryEnableNonClientDpiScaling(HWND hwnd) {
+    if (hwnd == nullptr) {
+        return;
+    }
+
+    const HMODULE user32 = GetModuleHandleW(L"user32.dll");
+    if (user32 == nullptr) {
+        return;
+    }
+
+    using EnableNonClientDpiScalingFn = BOOL(WINAPI*)(HWND);
+    const auto enableNonClientDpiScaling =
+        reinterpret_cast<EnableNonClientDpiScalingFn>(
+            GetProcAddress(user32, "EnableNonClientDpiScaling"));
+    if (enableNonClientDpiScaling != nullptr) {
+        enableNonClientDpiScaling(hwnd);
+    }
+}
+
+} // namespace
+
+Application* WindowMessageDispatcher::GetApplicationFromWindow(HWND hwnd) {
+    return reinterpret_cast<Application*>(GetWindowLongPtrW(hwnd, GWLP_USERDATA));
+}
+
+bool WindowMessageDispatcher::TryHandleNonClientCreate(
+    HWND hwnd,
+    UINT message,
+    LPARAM lParam,
+    LRESULT& outResult) {
+    if (message != WM_NCCREATE) {
+        return false;
+    }
+
+    TryEnableNonClientDpiScaling(hwnd);
+    const auto* createStruct = reinterpret_cast<CREATESTRUCTW*>(lParam);
+    auto* application = reinterpret_cast<Application*>(createStruct->lpCreateParams);
+    SetWindowLongPtrW(hwnd, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(application));
+    outResult = TRUE;
+    return true;
+}
+
+bool WindowMessageDispatcher::TryDispatch(
+    Application& application,
+    UINT message,
+    WPARAM wParam,
+    LPARAM lParam,
+    LRESULT& outResult) {
+    switch (message) {
+    case WM_SETCURSOR:
+        if (LOWORD(lParam) == HTCLIENT && application.ApplyCurrentCursor()) {
+            outResult = TRUE;
+            return true;
+        }
+        return false;
+    case WM_DPICHANGED:
+        if (lParam == 0) {
+            return false;
+        }
+        application.OnDpiChanged(
+            static_cast<UINT>(LOWORD(wParam)),
+            *reinterpret_cast<const RECT*>(lParam));
+        RequestDeferredRenderFrame(application);
+        outResult = 0;
+        return true;
+    case WM_ENTERSIZEMOVE:
+        application.OnEnterSizeMove();
+        outResult = 0;
+        return true;
+    case WM_EXITSIZEMOVE:
+        application.OnExitSizeMove();
+        RequestDeferredRenderFrame(application);
+        outResult = 0;
+        return true;
+    case WM_SIZE:
+        if (wParam != SIZE_MINIMIZED) {
+            application.OnResize();
+            RequestDeferredRenderFrame(application);
+        }
+        outResult = 0;
+        return true;
+    case kDeferredRenderMessage:
+        application.OnDeferredRenderMessage();
+        outResult = 0;
+        return true;
+    case WM_PAINT:
+        application.OnPaintMessage();
+        outResult = 0;
+        return true;
+    default:
+        return false;
+    }
+}
+
+void WindowMessageDispatcher::RequestDeferredRenderFrame(Application& application) {
+    if (application.m_hwnd == nullptr ||
+        !IsWindow(application.m_hwnd) ||
+        !application.m_hostRuntime.TryQueueDeferredRender()) {
+        return;
+    }
+
+    PostMessageW(application.m_hwnd, kDeferredRenderMessage, 0, 0);
+}
+
+} // namespace XCEngine::UI::Editor::Host