Detached OffscreenCanvas should not transfer ImageBuffer

https://bugs.webkit.org/show_bug.cgi?id=275144 rdar://129270155 Reviewed by Simon Fraser. The buffer cannot contain anything, as only the context-less OffscreenCanvases can be detached. * Source/WebCore/bindings/js/SerializedScriptValue.cpp: (WebCore::SerializedScriptValue::computeMemoryCost const): * Source/WebCore/html/OffscreenCanvas.cpp: (WebCore::DetachedOffscreenCanvas::DetachedOffscreenCanvas): (WebCore::OffscreenCanvas::create): (WebCore::OffscreenCanvas::detach): (WebCore::DetachedOffscreenCanvas::takeImageBuffer): Deleted. (WebCore::OffscreenCanvas::takeImageBuffer const): Deleted. * Source/WebCore/html/OffscreenCanvas.h: (WebCore::DetachedOffscreenCanvas::originClean const): (WebCore::DetachedOffscreenCanvas::memoryCost const): Deleted. Canonical link: https://commits.webkit.org/279775@main
WebKit · Jun 6, 2024 · fa20ed6 · fa20ed6
1 parent d637301
commit fa20ed6
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Showing 3 changed files with 4 additions and 44 deletions.
diff --git a/Source/WebCore/bindings/js/SerializedScriptValue.cpp b/Source/WebCore/bindings/js/SerializedScriptValue.cpp
@@ -5873,12 +5873,6 @@ size_t SerializedScriptValue::computeMemoryCost() const
             cost += detachedImageBitmap->memoryCost();
     }
 
-#if ENABLE(OFFSCREEN_CANVAS_IN_WORKERS)
-    for (auto& canvas : m_internals.detachedOffscreenCanvases) {
-        if (canvas)
-            cost += canvas->memoryCost();
-    }
-#endif
 #if ENABLE(WEB_RTC)
     for (auto& channel : m_internals.detachedRTCDataChannels) {
         if (channel)

diff --git a/Source/WebCore/html/OffscreenCanvas.cpp b/Source/WebCore/html/OffscreenCanvas.cpp
@@ -93,23 +93,15 @@ class OffscreenCanvasPlaceholderData : public ThreadSafeRefCounted<OffscreenCanv
     RefPtr<ImageBufferPipe::Source> m_pipeSource;
 };
 
-DetachedOffscreenCanvas::DetachedOffscreenCanvas(std::unique_ptr<SerializedImageBuffer> buffer, const IntSize& size, bool originClean, RefPtr<OffscreenCanvasPlaceholderData> placeholderData)
-    : m_buffer(WTFMove(buffer))
-    , m_placeholderData(WTFMove(placeholderData))
+DetachedOffscreenCanvas::DetachedOffscreenCanvas(const IntSize& size, bool originClean, RefPtr<OffscreenCanvasPlaceholderData> placeholderData)
+    : m_placeholderData(WTFMove(placeholderData))
     , m_size(size)
     , m_originClean(originClean)
 {
 }
 
 DetachedOffscreenCanvas::~DetachedOffscreenCanvas() = default;
 
-RefPtr<ImageBuffer> DetachedOffscreenCanvas::takeImageBuffer(ScriptExecutionContext& context)
-{
-    if (!m_buffer)
-        return nullptr;
-    return SerializedImageBuffer::sinkIntoImageBuffer(WTFMove(m_buffer), context.graphicsClient());
-}
-
 RefPtr<OffscreenCanvasPlaceholderData> DetachedOffscreenCanvas::takePlaceholderData()
 {
     return WTFMove(m_placeholderData);
@@ -138,7 +130,6 @@ Ref<OffscreenCanvas> OffscreenCanvas::create(ScriptExecutionContext& scriptExecu
 Ref<OffscreenCanvas> OffscreenCanvas::create(ScriptExecutionContext& scriptExecutionContext, std::unique_ptr<DetachedOffscreenCanvas>&& detachedCanvas)
 {
     Ref<OffscreenCanvas> clone = adoptRef(*new OffscreenCanvas(scriptExecutionContext, detachedCanvas->size(), detachedCanvas->takePlaceholderData()));
-    clone->setImageBuffer(detachedCanvas->takeImageBuffer(scriptExecutionContext));
     if (!detachedCanvas->originClean())
         clone->setOriginTainted();
     clone->suspendIfNeeded();
@@ -473,7 +464,7 @@ std::unique_ptr<DetachedOffscreenCanvas> OffscreenCanvas::detach()
 
     m_detached = true;
 
-    auto detached = makeUnique<DetachedOffscreenCanvas>(takeImageBuffer(), size(), originClean(), WTFMove(m_placeholderData));
+    auto detached = makeUnique<DetachedOffscreenCanvas>(size(), originClean(), WTFMove(m_placeholderData));
     setSize(IntSize(0, 0));
     return detached;
 }
@@ -535,20 +526,6 @@ void OffscreenCanvas::setImageBufferAndMarkDirty(RefPtr<ImageBuffer>&& buffer)
     CanvasBase::didDraw(FloatRect(FloatPoint(), size()));
 }
 
-std::unique_ptr<SerializedImageBuffer> OffscreenCanvas::takeImageBuffer() const
-{
-    ASSERT(m_detached);
-
-    if (size().isEmpty())
-        return nullptr;
-
-    clearCopiedImage();
-    RefPtr<ImageBuffer> buffer = setImageBuffer(nullptr);
-    if (!buffer)
-        return nullptr;
-    return ImageBuffer::sinkIntoSerializedImageBuffer(WTFMove(buffer));
-}
-
 void OffscreenCanvas::reset()
 {
     resetGraphicsContextState();

diff --git a/Source/WebCore/html/OffscreenCanvas.h b/Source/WebCore/html/OffscreenCanvas.h
@@ -82,23 +82,13 @@ class DetachedOffscreenCanvas {
     friend class OffscreenCanvas;
 
 public:
-    DetachedOffscreenCanvas(std::unique_ptr<SerializedImageBuffer>, const IntSize&, bool originClean, RefPtr<OffscreenCanvasPlaceholderData>);
+    DetachedOffscreenCanvas(const IntSize&, bool originClean, RefPtr<OffscreenCanvasPlaceholderData>);
     WEBCORE_EXPORT ~DetachedOffscreenCanvas();
-
-    RefPtr<ImageBuffer> takeImageBuffer(ScriptExecutionContext&);
     const IntSize& size() const { return m_size; }
     bool originClean() const { return m_originClean; }
-    size_t memoryCost() const
-    {
-        auto* buffer = m_buffer.get();
-        if (buffer)
-            return buffer->memoryCost();
-        return 0;
-    }
     RefPtr<OffscreenCanvasPlaceholderData> takePlaceholderData();
 
 private:
-    std::unique_ptr<SerializedImageBuffer> m_buffer;
     RefPtr<OffscreenCanvasPlaceholderData> m_placeholderData;
     IntSize m_size;
     bool m_originClean;
@@ -181,7 +171,6 @@ class OffscreenCanvas final : public ActiveDOMObject, public RefCounted<Offscree
     void setSize(const IntSize&) final;
 
     void createImageBuffer() const final;
-    std::unique_ptr<SerializedImageBuffer> takeImageBuffer() const;
 
     void reset();
     void scheduleCommitToPlaceholderCanvas();