[WebGPU] Crash PresentationContextIOSurface::getCurrentTexture if con…

…text is not configured

https://bugs.webkit.org/show_bug.cgi?id=269103
<radar://122671890>

Reviewed by Dan Glastonbury.

An IPC call made directly to getCurrentTexture may result in a scenario where
the IOSurfaces have not yet been created. In this case, we want to return nullptr
to the caller.

* Source/WebCore/Modules/WebGPU/Implementation/WebGPUPresentationContextImpl.cpp:
(WebCore::WebGPU::PresentationContextImpl::getCurrentTexture):
* Source/WebGPU/WebGPU/PresentationContextIOSurface.mm:
(WebGPU::PresentationContextIOSurface::getCurrentTexture):
(WebGPU::PresentationContextIOSurface::getCurrentTextureView):

Canonical link: https://commits.webkit.org/274452@main

Source/WebCore/Modules/WebGPU/Implementation/WebGPUPresentationContextImpl.cpp

@@ -91,8 +91,10 @@ RefPtr<Texture> PresentationContextImpl::getCurrentTexture()
         return nullptr; // FIXME: This should return an invalid texture instead.
 
     if (!m_currentTexture) {
-        ASSERT(m_swapChain);
-        m_currentTexture = TextureImpl::create(WebGPUPtr<WGPUTexture> { wgpuSwapChainGetCurrentTexture(m_swapChain.get()) }, m_format, TextureDimension::_2d, m_convertToBackingContext);
+        auto texturePtr = wgpuSwapChainGetCurrentTexture(m_swapChain.get());
+        if (!texturePtr)
+            return nullptr;
+        m_currentTexture = TextureImpl::create(WebGPUPtr<WGPUTexture> { texturePtr }, m_format, TextureDimension::_2d, m_convertToBackingContext);
     }
 
     return m_currentTexture;

Source/WebGPU/WebGPU/PresentationContextIOSurface.mm

@@ -164,15 +164,19 @@
 
 Texture* PresentationContextIOSurface::getCurrentTexture()
 {
-    ASSERT(m_ioSurfaces.count == m_renderBuffers.size());
+    if (m_ioSurfaces.count != m_renderBuffers.size() || m_renderBuffers.size() <= m_currentIndex)
+        return nullptr;
+
     auto& texture = m_renderBuffers[m_currentIndex].texture;
     texture->recreateIfNeeded();
     return texture.ptr();
 }
 
 TextureView* PresentationContextIOSurface::getCurrentTextureView()
 {
-    ASSERT(m_ioSurfaces.count == m_renderBuffers.size());
+    if (m_ioSurfaces.count != m_renderBuffers.size() || m_renderBuffers.size() <= m_currentIndex)
+        return nullptr;
+
     return m_renderBuffers[m_currentIndex].textureView.ptr();
 }