Refactor caret animation out of FrameSelection

https://bugs.webkit.org/show_bug.cgi?id=248112
rdar://102535758

Reviewed by Simon Fraser and Darin Adler.

Simplifies `FrameSelection` by factoring out the animation logic into its own
class, to fit with how we handle other animations. Instead of `FrameSelection`
owning its own caret blinking timer, the caret is now subject to the repaint cycle
of `Page::updateRendering`.

This PR introduces a new `CaretAnimation` virtual class, with a `CaretAnimationSimple`
subclass to model how the current caret blinking works. This inheritence
hierarchy is modelled after how `ScrollAnimation` works.

The CaretAnimation now owns a timer, which when fired, schedules a rendering
update for the caret to update its appearance. When the rendering update happens,
`CaretAnimation::serviceAnimation` is triggered, which performs the actual
adjustment to the caret's presentation's properties. `FrameSelection::invalidateCaretRect`
is then triggered which causes the actual painting of the care to reflect its
new appearance.

Note that because the animation is now tied to `Page::updateRendering`,
`CaretAnimation::serviceAnimation` may be called at any given time, and so the
animation must track when the last time it was called was and account for this.

* Source/WebCore/Headers.cmake:
* Source/WebCore/Sources.txt:
* Source/WebCore/WebCore.xcodeproj/project.pbxproj:
* Source/WebCore/dom/Document.cpp:
(WebCore::Document::serviceCaretAnimation):
* Source/WebCore/dom/Document.h:
* Source/WebCore/editing/FrameSelection.cpp:
(WebCore::FrameSelection::FrameSelection):
(WebCore::FrameSelection::willBeRemovedFromFrame):
(WebCore::FrameSelection::paintCaret):
(WebCore::FrameSelection::setCaretBlinkingSuspended):
(WebCore::FrameSelection::isCaretBlinkingSuspended const):
(WebCore::FrameSelection::caretAnimationDidUpdate):
(WebCore::FrameSelection::document):
(WebCore::FrameSelection::updateAppearance):
(WebCore::FrameSelection::setCaretVisibility):
(WebCore::FrameSelection::setCaretColor):
(WebCore::FrameSelection::caretBlinkTimerFired): Deleted.
(WebCore::FrameSelection::setCaretBlinks): Deleted.
* Source/WebCore/editing/FrameSelection.h:
(WebCore::FrameSelection::currentCaretAnimator):
(WebCore::FrameSelection::currentCaretAnimator const):
(WebCore::FrameSelection::setCaretBlinkingSuspended): Deleted.
(WebCore::FrameSelection::isCaretBlinkingSuspended const): Deleted.
* Source/WebCore/page/Page.cpp:
(WebCore::Page::updateRendering):
(WebCore::Page::finalizeRenderingUpdate):
(WebCore::operator<<):
* Source/WebCore/page/Page.h:
* Source/WebCore/platform/CaretAnimator.cpp: Added.
(WebCore::CaretAnimator::page const):
(WebCore::CaretAnimator::serviceCaretAnimation):
(WebCore::CaretAnimator::scheduleAnimation):
* Source/WebCore/platform/CaretAnimator.h: Added.
(WebCore::CaretAnimationClient::caretAnimationDidUpdate):
(WebCore::CaretAnimationClient::caretAnimationWillStart):
(WebCore::CaretAnimationClient::caretAnimationDidEnd):
(WebCore::CaretAnimator::CaretAnimator):
(WebCore::CaretAnimator::stop):
(WebCore::CaretAnimator::isActive const):
(WebCore::CaretAnimator::setCaretBlinkingSuspended):
(WebCore::CaretAnimator::isCaretBlinkingSuspended const):
(WebCore::CaretAnimator::didStart):
(WebCore::CaretAnimator::didEnd):
(WebCore::CaretAnimator::timeSinceStart const):
* Source/WebCore/platform/SimpleCaretAnimator.cpp: Added.
(WebCore::SimpleCaretAnimator::SimpleCaretAnimator):
(WebCore::SimpleCaretAnimator::serviceAnimation):
(WebCore::SimpleCaretAnimator::start):
(WebCore::SimpleCaretAnimator::debugDescription const):
* Source/WebCore/platform/SimpleCaretAnimator.h: Added.

Canonical link: https://commits.webkit.org/257219@main

Source/WebCore/Headers.cmake

@@ -1331,6 +1331,7 @@ set(WebCore_PRIVATE_FRAMEWORK_HEADERS
     page/scrolling/ThreadedScrollingTree.h
 
     platform/AbortableTaskQueue.h
+    platform/CaretAnimator.h
     platform/CPUMonitor.h
     platform/ColorChooser.h
     platform/ColorChooserClient.h
@@ -1454,6 +1455,7 @@ set(WebCore_PRIVATE_FRAMEWORK_HEADERS
     platform/SharedBuffer.h
     platform/SharedBufferChunkReader.h
     platform/SharedStringHash.h
+    platform/SimpleCaretAnimator.h
     platform/SleepDisabler.h
     platform/SleepDisablerClient.h
     platform/SleepDisablerIdentifier.h

Source/WebCore/Sources.txt

@@ -1927,6 +1927,7 @@ page/scrolling/ScrollingTreeStickyNode.cpp
 page/scrolling/ThreadedScrollingCoordinator.cpp
 page/scrolling/ThreadedScrollingTree.cpp
 page/scrolling/ThreadedScrollingTreeScrollingNodeDelegate.cpp
+platform/CaretAnimator.cpp
 platform/CommonAtomStrings.cpp
 platform/ContentType.cpp
 platform/ContextMenu.cpp
@@ -2000,6 +2001,7 @@ platform/SerializedPlatformDataCue.cpp
 platform/SharedBuffer.cpp
 platform/SharedBufferChunkReader.cpp
 platform/SharedStringHash.cpp
+platform/SimpleCaretAnimator.cpp
 platform/SleepDisabler.cpp
 platform/SleepDisablerClient.cpp
 platform/SystemSoundManager.cpp

Source/WebCore/WebCore.xcodeproj/project.pbxproj

@@ -122,6 +122,8 @@
 		073B87671E4385AC0071C0EC /* AudioSampleBufferList.h in Headers */ = {isa = PBXBuildFile; fileRef = 073B87631E43859D0071C0EC /* AudioSampleBufferList.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		073B87691E4385AC0071C0EC /* AudioSampleDataSource.h in Headers */ = {isa = PBXBuildFile; fileRef = 073B87651E43859D0071C0EC /* AudioSampleDataSource.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		0740B14425DE31F800E38DBA /* MockMediaSessionCoordinator.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 0740B14325DE31A900E38DBA /* MockMediaSessionCoordinator.cpp */; };
+		0742C4FD2926C73C00D26990 /* CaretAnimator.h in Headers */ = {isa = PBXBuildFile; fileRef = 0742C4FB2926C73C00D26990 /* CaretAnimator.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		0742C5052926E29500D26990 /* SimpleCaretAnimator.h in Headers */ = {isa = PBXBuildFile; fileRef = 0742C5032926E29500D26990 /* SimpleCaretAnimator.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		074E82BB18A69F0E007EF54C /* PlatformTimeRanges.h in Headers */ = {isa = PBXBuildFile; fileRef = 074E82B918A69F0E007EF54C /* PlatformTimeRanges.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		075033A8252BD36800F70CE3 /* VideoPlaybackQualityMetrics.h in Headers */ = {isa = PBXBuildFile; fileRef = 075033A6252BD36800F70CE3 /* VideoPlaybackQualityMetrics.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		0753860314489E9800B78452 /* CachedTextTrack.h in Headers */ = {isa = PBXBuildFile; fileRef = 0753860114489E9800B78452 /* CachedTextTrack.h */; };
@@ -6258,6 +6260,10 @@
 		073B87651E43859D0071C0EC /* AudioSampleDataSource.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = AudioSampleDataSource.h; sourceTree = "<group>"; };
 		0740B14125DE31A800E38DBA /* MockMediaSessionCoordinator.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = MockMediaSessionCoordinator.h; sourceTree = "<group>"; };
 		0740B14325DE31A900E38DBA /* MockMediaSessionCoordinator.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = MockMediaSessionCoordinator.cpp; sourceTree = "<group>"; };
+		0742C4FA2926C73C00D26990 /* CaretAnimator.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = CaretAnimator.cpp; sourceTree = "<group>"; };
+		0742C4FB2926C73C00D26990 /* CaretAnimator.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = CaretAnimator.h; sourceTree = "<group>"; };
+		0742C5022926E29500D26990 /* SimpleCaretAnimator.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = SimpleCaretAnimator.cpp; sourceTree = "<group>"; };
+		0742C5032926E29500D26990 /* SimpleCaretAnimator.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SimpleCaretAnimator.h; sourceTree = "<group>"; };
 		074471FD25E180050054B231 /* MediaSessionReadyState.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = MediaSessionReadyState.h; sourceTree = "<group>"; };
 		074471FF25E180050054B231 /* MediaSessionReadyState.idl */ = {isa = PBXFileReference; lastKnownFileType = text; path = MediaSessionReadyState.idl; sourceTree = "<group>"; };
 		0744ECEB1E0C4AE5000D0944 /* MockAudioSharedUnit.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MockAudioSharedUnit.h; sourceTree = "<group>"; };
@@ -31022,6 +31028,8 @@
 				E1EE8B6B2412B2A700E794D6 /* xr */,
 				DFDB912CF8E88A6DA1AD264F /* AbortableTaskQueue.h */,
 				E3A86FC12695EB480059264D /* CaptionPreferencesDelegate.h */,
+				0742C4FA2926C73C00D26990 /* CaretAnimator.cpp */,
+				0742C4FB2926C73C00D26990 /* CaretAnimator.h */,
 				C330A22113EC196B0000B45B /* ColorChooser.h */,
 				C37CDEBC149EF2030042090D /* ColorChooserClient.h */,
 				BCC8CFCA0986CD2400140BF2 /* ColorData.gperf */,
@@ -31232,6 +31240,8 @@
 				834DFACE1F7DAE5700C2725B /* SharedStringHash.cpp */,
 				834DFACC1F7DAE5600C2725B /* SharedStringHash.h */,
 				93309EA0099EB78C0056E581 /* SharedTimer.h */,
+				0742C5022926E29500D26990 /* SimpleCaretAnimator.cpp */,
+				0742C5032926E29500D26990 /* SimpleCaretAnimator.h */,
 				C149D559242EA4F8003EBB12 /* SleepDisabler.cpp */,
 				C149D55A242EA4F9003EBB12 /* SleepDisabler.h */,
 				C18FB518242F9382007E9875 /* SleepDisablerClient.cpp */,
@@ -35009,6 +35019,7 @@
 				079D086B162F21F900DB8658 /* CaptionUserPreferencesMediaAF.h in Headers */,
 				07B7116D1D899E63009F0FFB /* CaptureDevice.h in Headers */,
 				07B7116F1D899E63009F0FFB /* CaptureDeviceManager.h in Headers */,
+				0742C4FD2926C73C00D26990 /* CaretAnimator.h in Headers */,
 				E4F0BE3125712F6E009E7431 /* CaretRectComputation.h in Headers */,
 				CDC734151977896D0046BFC5 /* CARingBuffer.h in Headers */,
 				E4ABABF52368C6EF00FA4345 /* CascadeLevel.h in Headers */,
@@ -38636,6 +38647,7 @@
 				1C4DB02627339FE0007B0AD1 /* ShouldLocalizeAxisNames.h in Headers */,
 				DF19E2AC24772BC1007BDACB /* ShouldRelaxThirdPartyCookieBlocking.h in Headers */,
 				8362E8C120CEF9CB00245886 /* ShouldTreatAsContinuingLoad.h in Headers */,
+				0742C5052926E29500D26990 /* SimpleCaretAnimator.h in Headers */,
 				9316DDFB240C64B4009340AA /* SimpleRange.h in Headers */,
 				C5A1EA7D152BCF08004D00B6 /* SimplifyMarkupCommand.h in Headers */,
 				572A7F211C6E5719009C6149 /* SimulatedClick.h in Headers */,

Source/WebCore/dom/Document.cpp

@@ -6904,6 +6904,12 @@ void Document::serviceRequestAnimationFrameCallbacks()
         m_scriptedAnimationController->serviceRequestAnimationFrameCallbacks(domWindow()->frozenNowTimestamp());
 }
 
+void Document::serviceCaretAnimation()
+{
+    if (auto* window = domWindow())
+        selection().caretAnimator().serviceCaretAnimation(window->frozenNowTimestamp());
+}
+
 void Document::serviceRequestVideoFrameCallbacks()
 {
 #if ENABLE(VIDEO)

Source/WebCore/dom/Document.h

@@ -1151,6 +1151,8 @@ class Document
     void serviceRequestAnimationFrameCallbacks();
     void serviceRequestVideoFrameCallbacks();
 
+    void serviceCaretAnimation();
+
     void windowScreenDidChange(PlatformDisplayID);
 
     void finishedParsing();

Source/WebCore/editing/FrameSelection.cpp

@@ -27,8 +27,10 @@
 #include "FrameSelection.h"
 
 #include "AXObjectCache.h"
+#include "CaretAnimator.h"
 #include "CharacterData.h"
 #include "ColorBlending.h"
+#include "DOMWindow.h"
 #include "DeleteSelectionCommand.h"
 #include "DocumentInlines.h"
 #include "Editing.h"
@@ -69,6 +71,7 @@
 #include "RenderedPosition.h"
 #include "ScriptDisallowedScope.h"
 #include "Settings.h"
+#include "SimpleCaretAnimator.h"
 #include "SimpleRange.h"
 #include "SpatialNavigation.h"
 #include "StyleProperties.h"
@@ -163,22 +166,17 @@ static inline bool isPageActive(Document* document)
 FrameSelection::FrameSelection(Document* document)
     : m_document(document)
     , m_granularity(TextGranularity::CharacterGranularity)
-#if ENABLE(TEXT_CARET)
-    , m_caretBlinkTimer(*this, &FrameSelection::caretBlinkTimerFired)
-#endif
     , m_appearanceUpdateTimer(*this, &FrameSelection::appearanceUpdateTimerFired)
+    , m_caretAnimator(makeUniqueRef<SimpleCaretAnimator>(*this))
     , m_caretInsidePositionFixed(false)
     , m_absCaretBoundsDirty(true)
-    , m_caretPaint(true)
-    , m_isCaretBlinkingSuspended(false)
     , m_focused(document && document->frame() && document->page() && document->page()->focusController().focusedFrame() == document->frame())
     , m_isActive(isPageActive(document))
     , m_shouldShowBlockCursor(false)
     , m_pendingSelectionUpdate(false)
     , m_alwaysAlignCursorOnScrollWhenRevealingSelection(false)
 #if PLATFORM(IOS_FAMILY)
     , m_updateAppearanceEnabled(false)
-    , m_caretBlinks(true)
 #endif
 {
     if (shouldAlwaysUseDirectionalSelection(m_document.get()))
@@ -195,6 +193,8 @@ FrameSelection::FrameSelection(Document* document)
 #endif
 }
 
+FrameSelection::~FrameSelection() = default;
+
 Element* FrameSelection::rootEditableElementOrDocumentElement() const
 {
     Element* selectionRoot = m_selection.rootEditableElement();
@@ -1641,7 +1641,7 @@ void FrameSelection::willBeRemovedFromFrame()
     m_granularity = TextGranularity::CharacterGranularity;
 
 #if ENABLE(TEXT_CARET)
-    m_caretBlinkTimer.stop();
+    caretAnimator().stop();
 #endif
 
     if (auto* view = m_document->renderView())
@@ -1839,7 +1839,7 @@ void CaretBase::invalidateCaretRect(Node* node, bool caretRectChanged)
 
 void FrameSelection::paintCaret(GraphicsContext& context, const LayoutPoint& paintOffset, const LayoutRect& clipRect)
 {
-    if (m_selection.isCaret() && m_caretPaint && m_selection.start().deprecatedNode())
+    if (m_selection.isCaret() && caretAnimator().isVisible() && m_selection.start().deprecatedNode())
         CaretBase::paintCaret(*m_selection.start().deprecatedNode(), context, paintOffset, clipRect);
 }
 
@@ -1895,6 +1895,26 @@ void CaretBase::paintCaret(const Node& node, GraphicsContext& context, const Lay
 #endif
 }
 
+void FrameSelection::setCaretBlinkingSuspended(bool suspended)
+{
+    caretAnimator().setBlinkingSuspended(suspended);
+}
+
+bool FrameSelection::isCaretBlinkingSuspended() const
+{
+    return caretAnimator().isBlinkingSuspended();
+}
+
+void FrameSelection::caretAnimationDidUpdate(CaretAnimator&)
+{
+    invalidateCaretRect();
+}
+
+Document* FrameSelection::document()
+{
+    return m_document.get();
+}
+
 void FrameSelection::debugRenderer(RenderObject* renderer, bool selected) const
 {
     if (is<Element>(*renderer->node())) {
@@ -2229,18 +2249,15 @@ void FrameSelection::updateAppearance()
     // If the caret moved, stop the blink timer so we can restart with a
     // black caret in the new location.
     if (caretRectChangedOrCleared || !shouldBlink || shouldStopBlinkingDueToTypingCommand(m_document.get()))
-        m_caretBlinkTimer.stop();
+        caretAnimator().stop();
 
     // Start blinking with a black caret. Be sure not to restart if we're
     // already blinking in the right location.
-    if (shouldBlink && !m_caretBlinkTimer.isActive()) {
-        if (Seconds blinkInterval = RenderTheme::singleton().caretBlinkInterval())
-            m_caretBlinkTimer.startRepeating(blinkInterval);
+    if (shouldBlink && !caretAnimator().isActive()) {
+        if (m_document && m_document->domWindow())
+            caretAnimator().start(m_document->domWindow()->nowTimestamp());
 
-        if (!m_caretPaint) {
-            m_caretPaint = true;
-            invalidateCaretRect();
-        }
+        caretAnimator().setVisible(true);
     }
 #endif
 
@@ -2299,31 +2316,15 @@ void FrameSelection::setCaretVisibility(CaretVisibility visibility, ShouldUpdate
         updateSelectionAppearanceNow();
 
 #if ENABLE(TEXT_CARET)
-    if (m_caretPaint) {
-        m_caretPaint = false;
-        invalidateCaretRect();
-    }
+    caretAnimator().setVisible(false);
+
     CaretBase::setCaretVisibility(visibility);
 #endif
 
     if (doAppearanceUpdate == ShouldUpdateAppearance::Yes)
         updateAppearance();
 }
 
-void FrameSelection::caretBlinkTimerFired()
-{
-#if ENABLE(TEXT_CARET)
-    if (!isCaret())
-        return;
-    ASSERT(caretIsVisible());
-    bool caretPaint = m_caretPaint;
-    if (isCaretBlinkingSuspended() && caretPaint)
-        return;
-    m_caretPaint = !caretPaint;
-    invalidateCaretRect();
-#endif
-}
-
 // Helper function that tells whether a particular node is an element that has an entire
 // Frame and FrameView, a <frame>, <iframe>, or <object>.
 static bool isFrameElement(const Node* n)
@@ -2870,28 +2871,11 @@ void FrameSelection::clearCurrentSelection()
     setSelection(VisibleSelection());
 }
 
-void FrameSelection::setCaretBlinks(bool caretBlinks)
-{
-    if (m_caretBlinks == caretBlinks)
-        return;
-#if ENABLE(TEXT_CARET)
-    m_document->updateLayoutIgnorePendingStylesheets();
-    if (m_caretPaint) {
-        m_caretPaint = false; 
-        invalidateCaretRect(); 
-    }
-#endif
-    if (caretBlinks)
-        setFocusedElementIfNeeded();
-    m_caretBlinks = caretBlinks;
-    updateAppearance();
-}
-
 void FrameSelection::setCaretColor(const Color& caretColor)
 {
     if (m_caretColor != caretColor) {
         m_caretColor = caretColor;
-        if (caretIsVisible() && m_caretBlinks && isCaret())
+        if (caretIsVisible() && isCaret())
             invalidateCaretRect();
     }
 }