[UnifiedPDF] When an incremental PDF completes its load, blank pages …

…are still visible

https://bugs.webkit.org/show_bug.cgi?id=273917
rdar://127713604

Reviewed by Tim Horton.

While loading an incremental PDF (potentially over a slow network connection), nothing
currently triggers repaints, so we never show pages as they load, nor do we repaint all
the pages when the load completes. This can leave you with blank pages until you scroll
or zoom.

Fix by hooking up some virtual functions on the plugin to give UnifiedPDFPlugin a way
to know when incremental loads progress, finish or cancel. While progressing, fire
a repeating timer every 1s to trigger repaints (we currently can't know which pages
become valid based on data ranges). Also trigger a repaint when the load completes.
This repaints use the coverage rect to only invalidate visible pages.

* Source/WebKit/WebProcess/Plugins/PDF/PDFPluginBase.h:
(WebKit::PDFPluginBase::incrementalLoadingDidProgress):
(WebKit::PDFPluginBase::incrementalLoadingDidCancel):
(WebKit::PDFPluginBase::incrementalLoadingDidFinish):
* Source/WebKit/WebProcess/Plugins/PDF/PDFPluginBase.mm:
(WebKit::PDFPluginBase::streamDidReceiveData):
(WebKit::PDFPluginBase::streamDidFinishLoading):
(WebKit::PDFPluginBase::streamDidFail):
(WebKit::PDFPluginBase::receivedNonLinearizedPDFSentinel):
* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/AsyncPDFRenderer.mm:
(WebKit::AsyncPDFRenderer::coverageRectDidChange):
* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/PDFDocumentLayout.h:
* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/PDFDocumentLayout.mm:
(WebKit::PDFDocumentLayout::contentsSize const):
* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.h:
* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.mm:
(WebKit::UnifiedPDFPlugin::installPDFDocument):
(WebKit::UnifiedPDFPlugin::incrementalLoadingDidProgress):
(WebKit::UnifiedPDFPlugin::incrementalLoadingDidCancel):
(WebKit::UnifiedPDFPlugin::incrementalLoadingDidFinish):
(WebKit::UnifiedPDFPlugin::updatePageBackgroundLayers):
(WebKit::UnifiedPDFPlugin::incrementalLoadingRepaintTimerFired):
(WebKit::UnifiedPDFPlugin::repaintForIncrementalLoad):
(WebKit::UnifiedPDFPlugin::paintContents):

Canonical link: https://commits.webkit.org/278597@main

Source/WebKit/WebProcess/Plugins/PDF/PDFPluginBase.h

@@ -344,6 +344,10 @@ class PDFPluginBase : public ThreadSafeRefCountedAndCanMakeThreadSafeWeakPtr<PDF
     virtual Ref<WebCore::Scrollbar> createScrollbar(WebCore::ScrollbarOrientation);
     virtual void destroyScrollbar(WebCore::ScrollbarOrientation);
 
+    virtual void incrementalLoadingDidProgress() { }
+    virtual void incrementalLoadingDidCancel() { }
+    virtual void incrementalLoadingDidFinish() { }
+
 #if ENABLE(PDF_HUD)
     void updateHUDLocation();
     WebCore::IntRect frameForHUDInRootViewCoordinates() const;

Source/WebKit/WebProcess/Plugins/PDF/PDFPluginBase.mm

@@ -386,6 +386,8 @@
     if (m_incrementalLoader)
         m_incrementalLoader->incrementalPDFStreamDidReceiveData(buffer);
 #endif
+
+    incrementalLoadingDidProgress();
 }
 
 void PDFPluginBase::streamDidFinishLoading()
@@ -415,6 +417,7 @@
         installPDFDocument();
     }
 
+    incrementalLoadingDidFinish();
     tryRunScriptsInPDFDocument();
 
 #if ENABLE(PDF_HUD)
@@ -436,6 +439,8 @@
     if (m_incrementalLoader)
         m_incrementalLoader->incrementalPDFStreamDidFail();
 #endif
+
+    incrementalLoadingDidCancel();
 }
 
 #if HAVE(INCREMENTAL_PDF_APIS)
@@ -518,6 +523,8 @@
     if (m_incrementalLoader)
         m_incrementalLoader->receivedNonLinearizedPDFSentinel();
 
+    incrementalLoadingDidCancel();
+
     if (!m_documentFinishedLoading || m_pdfDocument)
         return;
 

Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/AsyncPDFRenderer.mm

@@ -224,8 +224,6 @@
     auto pageCoverage = plugin->pageCoverageForRect(coverageRect);
     auto pagePreviewScale = plugin->scaleForPagePreviews();
 
-    LOG_WITH_STREAM(PDFAsyncRendering, stream << "AsyncPDFRenderer::coverageRectDidChange " << coverageRect << " " << pageCoverage << " - preview scale " << pagePreviewScale);
-
     PDFPageIndexSet unwantedPageIndices;
     for (auto pageIndex : m_pagePreviews.keys())
         unwantedPageIndices.add(pageIndex);
@@ -242,6 +240,8 @@
 
     for (auto pageIndex : unwantedPageIndices)
         removePreviewForPage(pageIndex);
+
+    LOG_WITH_STREAM(PDFAsyncRendering, stream << "AsyncPDFRenderer::coverageRectDidChange " << coverageRect << " " << pageCoverage << " - preview scale " << pagePreviewScale << " - have " << m_pagePreviews.size() << " page previews and " << m_enqueuedPagePreviews.size() << " enqueued");
 }
 
 void AsyncPDFRenderer::tilingScaleFactorDidChange(float)

Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/PDFDocumentLayout.h

@@ -93,6 +93,7 @@ class PDFDocumentLayout {
     float scale() const { return m_scale; }
 
     void updateLayout(WebCore::IntSize pluginSize, ShouldUpdateAutoSizeScale);
+    WebCore::FloatSize contentsSize() const;
     WebCore::FloatSize scaledContentsSize() const;
 
     void setDisplayMode(DisplayMode displayMode) { m_displayMode = displayMode; }

Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/PDFDocumentLayout.mm

@@ -413,6 +413,11 @@
     return m_pageGeometry[index].rotation;
 }
 
+FloatSize PDFDocumentLayout::contentsSize() const
+{
+    return m_documentBounds.size();
+}
+
 FloatSize PDFDocumentLayout::scaledContentsSize() const
 {
     return m_documentBounds.size().scaled(m_scale);

Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.h

@@ -199,6 +199,10 @@ class UnifiedPDFPlugin final : public PDFPluginBase, public WebCore::GraphicsLay
 
     void teardown() override;
 
+    void incrementalLoadingDidProgress() override;
+    void incrementalLoadingDidCancel() override;
+    void incrementalLoadingDidFinish() override;
+
     void installPDFDocument() override;
 
 #if ENABLE(UNIFIED_PDF_DATA_DETECTION)
@@ -425,6 +429,9 @@ class UnifiedPDFPlugin final : public PDFPluginBase, public WebCore::GraphicsLay
     void updateLayerHierarchy();
     void updateLayerPositions();
 
+    void incrementalLoadingRepaintTimerFired();
+    void repaintForIncrementalLoad();
+
     void didChangeScrollOffset() override;
     void didChangeIsInWindow();
 
@@ -592,6 +599,8 @@ class UnifiedPDFPlugin final : public PDFPluginBase, public WebCore::GraphicsLay
     bool m_inActiveAutoscroll { false };
     WebCore::Timer m_autoscrollTimer { *this, &UnifiedPDFPlugin::autoscrollTimerFired };
 
+    WebCore::Timer m_incrementalLoadingRepaintTimer { *this, &UnifiedPDFPlugin::incrementalLoadingRepaintTimerFired };
+
     RetainPtr<WKPDFFormMutationObserver> m_pdfMutationObserver;
 
 #if PLATFORM(MAC)

Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.mm

@@ -279,7 +279,24 @@ static String mutationObserverNotificationString()
         m_pdfTestCallback->handleEvent();
         m_pdfTestCallback = nullptr;
     }
+}
+
+void UnifiedPDFPlugin::incrementalLoadingDidProgress()
+{
+    static constexpr auto incrementalLoadRepaintInterval = 1_s;
+    if (!m_incrementalLoadingRepaintTimer.isActive())
+        m_incrementalLoadingRepaintTimer.startRepeating(incrementalLoadRepaintInterval);
+}
+
+void UnifiedPDFPlugin::incrementalLoadingDidCancel()
+{
+    m_incrementalLoadingRepaintTimer.stop();
+}
 
+void UnifiedPDFPlugin::incrementalLoadingDidFinish()
+{
+    m_incrementalLoadingRepaintTimer.stop();
+    repaintForIncrementalLoad();
 }
 
 #if ENABLE(UNIFIED_PDF_DATA_DETECTION)
@@ -563,6 +580,24 @@ static String mutationObserverNotificationString()
     m_pageBackgroundsContainerLayer->setChildren(WTFMove(pageContainerLayers));
 }
 
+void UnifiedPDFPlugin::incrementalLoadingRepaintTimerFired()
+{
+    repaintForIncrementalLoad();
+}
+
+void UnifiedPDFPlugin::repaintForIncrementalLoad()
+{
+    auto coverageRect = FloatRect { { }, m_documentLayout.contentsSize() };
+
+    if (auto* tiledBacking = m_contentsLayer->tiledBacking()) {
+        coverageRect = tiledBacking->coverageRect();
+
+        coverageRect = convertDown(CoordinateSpace::Contents, CoordinateSpace::PDFDocumentLayout, coverageRect);
+    }
+
+    setNeedsRepaintInDocumentRect(RepaintRequirement::PDFContent, coverageRect);
+}
+
 void UnifiedPDFPlugin::paintBackgroundLayerForPage(const GraphicsLayer*, GraphicsContext& context, const FloatRect& clipRect, PDFDocumentLayout::PageIndex pageIndex)
 {
     auto destinationRect = m_documentLayout.layoutBoundsForPageAtIndex(pageIndex);
@@ -895,7 +930,6 @@ static String mutationObserverNotificationString()
         paintBackgroundLayerForPage(layer, context, clipRect, *backgroundLayerPageIndex);
         return;
     }
-
 }
 
 PDFPageCoverage UnifiedPDFPlugin::pageCoverageForRect(const FloatRect& clipRect) const