Backport: Use dynamic_cast and assertion instead of static_cast to fail earlier if there

is a bug.

Backport of changeset 7984:0f23c38fa1ac.

1 files changed, 20 insertions, 13 deletions

diff --git a/win32/PlatWin.cxx b/win32/PlatWin.cxx
index 0102fbb01..febc82171 100644
--- a/win32/PlatWin.cxx
+++ b/win32/PlatWin.cxx
@@ -560,7 +560,9 @@ void SurfaceGDI::Init(SurfaceID sid, WindowID) {
 
 void SurfaceGDI::InitPixMap(int width, int height, Surface *surface_, WindowID) {
 	Release();
-	SurfaceGDI *psurfOther = static_cast<SurfaceGDI *>(surface_);
+	SurfaceGDI *psurfOther = dynamic_cast<SurfaceGDI *>(surface_);
+	// Should only ever be called with a SurfaceGDI, not a SurfaceD2D
+	PLATFORM_ASSERT(psurfOther);
 	hdc = ::CreateCompatibleDC(psurfOther->hdc);
 	hdcOwned = true;
 	bitmap = ::CreateCompatibleBitmap(psurfOther->hdc, width, height);
@@ -648,10 +650,12 @@ void SurfaceGDI::FillRectangle(PRectangle rc, ColourDesired back) {
 
 void SurfaceGDI::FillRectangle(PRectangle rc, Surface &surfacePattern) {
 	HBRUSH br;
-	if (static_cast<SurfaceGDI &>(surfacePattern).bitmap)
-		br = ::CreatePatternBrush(static_cast<SurfaceGDI &>(surfacePattern).bitmap);
-	else	// Something is wrong so display in red
+  SurfaceGDI *psgdi = dynamic_cast<SurfaceGDI *>(&surfacePattern);
+	if (psgdi && psgdi->bitmap) {
+		br = ::CreatePatternBrush(psgdi->bitmap);
+	} else {	// Something is wrong so display in red
 		br = ::CreateSolidBrush(RGB(0xff, 0, 0));
+	}
 	const RECT rcw = RectFromPRectangle(rc);
 	::FillRect(hdc, &rcw, br);
 	::DeleteObject(br);
@@ -980,6 +984,7 @@ class SurfaceD2D : public Surface {
 	int codePageText;
 
 	ID2D1RenderTarget *pRenderTarget;
+	ID2D1BitmapRenderTarget *pBitmapRenderTarget;
 	bool ownRenderTarget;
 	int clipsActive;
 
@@ -1061,6 +1066,7 @@ SurfaceD2D::SurfaceD2D() noexcept :
 	codePageText = 0;
 
 	pRenderTarget = nullptr;
+	pBitmapRenderTarget = nullptr;
 	ownRenderTarget = false;
 	clipsActive = 0;
 
@@ -1096,6 +1102,7 @@ void SurfaceD2D::Clear() noexcept {
 		}
 		pRenderTarget = nullptr;
 	}
+	pBitmapRenderTarget = nullptr;
 }
 
 void SurfaceD2D::Release() {
@@ -1132,8 +1139,9 @@ void SurfaceD2D::Init(SurfaceID sid, WindowID) {
 void SurfaceD2D::InitPixMap(int width, int height, Surface *surface_, WindowID) {
 	Release();
 	SetScale();
-	SurfaceD2D *psurfOther = static_cast<SurfaceD2D *>(surface_);
-	ID2D1BitmapRenderTarget *pCompatibleRenderTarget = nullptr;
+	SurfaceD2D *psurfOther = dynamic_cast<SurfaceD2D *>(surface_);
+	// Should only ever be called with a SurfaceD2D, not a SurfaceGDI
+	PLATFORM_ASSERT(psurfOther);
 	const D2D1_SIZE_F desiredSize = D2D1::SizeF(static_cast<float>(width), static_cast<float>(height));
 	D2D1_PIXEL_FORMAT desiredFormat;
 #ifdef __MINGW32__
@@ -1143,9 +1151,9 @@ void SurfaceD2D::InitPixMap(int width, int height, Surface *surface_, WindowID)
 #endif
 	desiredFormat.alphaMode = D2D1_ALPHA_MODE_IGNORE;
 	const HRESULT hr = psurfOther->pRenderTarget->CreateCompatibleRenderTarget(
-		&desiredSize, nullptr, &desiredFormat, D2D1_COMPATIBLE_RENDER_TARGET_OPTIONS_NONE, &pCompatibleRenderTarget);
+		&desiredSize, nullptr, &desiredFormat, D2D1_COMPATIBLE_RENDER_TARGET_OPTIONS_NONE, &pBitmapRenderTarget);
 	if (SUCCEEDED(hr)) {
-		pRenderTarget = pCompatibleRenderTarget;
+		pRenderTarget = pBitmapRenderTarget;
 		pRenderTarget->BeginDraw();
 		ownRenderTarget = true;
 	}
@@ -1301,12 +1309,11 @@ void SurfaceD2D::FillRectangle(PRectangle rc, ColourDesired back) {
 }
 
 void SurfaceD2D::FillRectangle(PRectangle rc, Surface &surfacePattern) {
-	SurfaceD2D &surfOther = static_cast<SurfaceD2D &>(surfacePattern);
-	surfOther.FlushDrawing();
+	SurfaceD2D *psurfOther = dynamic_cast<SurfaceD2D *>(&surfacePattern);
+	PLATFORM_ASSERT(psurfOther && psurfOther->pBitmapRenderTarget);
+	psurfOther->FlushDrawing();
 	ID2D1Bitmap *pBitmap = nullptr;
-	ID2D1BitmapRenderTarget *pCompatibleRenderTarget = reinterpret_cast<ID2D1BitmapRenderTarget *>(
-		surfOther.pRenderTarget);
-	HRESULT hr = pCompatibleRenderTarget->GetBitmap(&pBitmap);
+	HRESULT hr = psurfOther->pBitmapRenderTarget->GetBitmap(&pBitmap);
 	if (SUCCEEDED(hr)) {
 		ID2D1BitmapBrush *pBitmapBrush = nullptr;
 		const D2D1_BITMAP_BRUSH_PROPERTIES brushProperties =