Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 987 insertions, 0 deletions

diff --git a/layout/base/nsCaret.cpp b/layout/base/nsCaret.cpp
new file mode 100644
index 0000000000..bfad3bd416
--- /dev/null
+++ b/layout/base/nsCaret.cpp
@@ -0,0 +1,987 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* the caret is the text cursor used, e.g., when editing */
+
+#include "nsCaret.h"
+
+#include <algorithm>
+
+#include "gfxUtils.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/intl/BidiEmbeddingLevel.h"
+#include "mozilla/StaticPrefs_bidi.h"
+#include "nsCOMPtr.h"
+#include "nsFontMetrics.h"
+#include "nsITimer.h"
+#include "nsFrameSelection.h"
+#include "nsIFrame.h"
+#include "nsIScrollableFrame.h"
+#include "nsIContent.h"
+#include "nsIFrameInlines.h"
+#include "nsLayoutUtils.h"
+#include "nsPresContext.h"
+#include "nsBlockFrame.h"
+#include "nsISelectionController.h"
+#include "nsTextFrame.h"
+#include "nsXULPopupManager.h"
+#include "nsMenuPopupFrame.h"
+#include "nsTextFragment.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/dom/Selection.h"
+#include "nsIBidiKeyboard.h"
+#include "nsContentUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::gfx;
+
+using BidiEmbeddingLevel = mozilla::intl::BidiEmbeddingLevel;
+
+// The bidi indicator hangs off the caret to one side, to show which
+// direction the typing is in. It needs to be at least 2x2 to avoid looking
+// like an insignificant dot
+static const int32_t kMinBidiIndicatorPixels = 2;
+
+/**
+ * Find the first frame in an in-order traversal of the frame subtree rooted
+ * at aFrame which is either a text frame logically at the end of a line,
+ * or which is aStopAtFrame. Return null if no such frame is found. We don't
+ * descend into the children of non-eLineParticipant frames.
+ */
+static nsIFrame* CheckForTrailingTextFrameRecursive(nsIFrame* aFrame,
+                                                    nsIFrame* aStopAtFrame) {
+  if (aFrame == aStopAtFrame ||
+      ((aFrame->IsTextFrame() &&
+        (static_cast<nsTextFrame*>(aFrame))->IsAtEndOfLine())))
+    return aFrame;
+  if (!aFrame->IsFrameOfType(nsIFrame::eLineParticipant)) return nullptr;
+
+  for (nsIFrame* f : aFrame->PrincipalChildList()) {
+    nsIFrame* r = CheckForTrailingTextFrameRecursive(f, aStopAtFrame);
+    if (r) return r;
+  }
+  return nullptr;
+}
+
+static nsLineBox* FindContainingLine(nsIFrame* aFrame) {
+  while (aFrame && aFrame->IsFrameOfType(nsIFrame::eLineParticipant)) {
+    nsIFrame* parent = aFrame->GetParent();
+    nsBlockFrame* blockParent = do_QueryFrame(parent);
+    if (blockParent) {
+      bool isValid;
+      nsBlockInFlowLineIterator iter(blockParent, aFrame, &isValid);
+      return isValid ? iter.GetLine().get() : nullptr;
+    }
+    aFrame = parent;
+  }
+  return nullptr;
+}
+
+static void AdjustCaretFrameForLineEnd(nsIFrame** aFrame, int32_t* aOffset) {
+  nsLineBox* line = FindContainingLine(*aFrame);
+  if (!line) {
+    return;
+  }
+  int32_t count = line->GetChildCount();
+  for (nsIFrame* f = line->mFirstChild; count > 0;
+       --count, f = f->GetNextSibling()) {
+    nsIFrame* r = CheckForTrailingTextFrameRecursive(f, *aFrame);
+    if (r == *aFrame) {
+      return;
+    }
+    if (r) {
+      // We found our frame, but we may not be able to properly paint the caret
+      // if -moz-user-modify differs from our actual frame.
+      MOZ_ASSERT(r->IsTextFrame(), "Expected text frame");
+      *aFrame = r;
+      *aOffset = (static_cast<nsTextFrame*>(r))->GetContentEnd();
+      return;
+    }
+  }
+}
+
+static bool IsBidiUI() { return StaticPrefs::bidi_browser_ui(); }
+
+nsCaret::nsCaret()
+    : mOverrideOffset(0),
+      mBlinkCount(-1),
+      mBlinkRate(0),
+      mHideCount(0),
+      mIsBlinkOn(false),
+      mVisible(false),
+      mReadOnly(false),
+      mShowDuringSelection(false),
+      mIgnoreUserModify(true) {}
+
+nsCaret::~nsCaret() { StopBlinking(); }
+
+nsresult nsCaret::Init(PresShell* aPresShell) {
+  NS_ENSURE_ARG(aPresShell);
+
+  mPresShell =
+      do_GetWeakReference(aPresShell);  // the presshell owns us, so no addref
+  NS_ASSERTION(mPresShell, "Hey, pres shell should support weak refs");
+
+  mShowDuringSelection =
+      LookAndFeel::GetInt(LookAndFeel::IntID::ShowCaretDuringSelection,
+                          mShowDuringSelection ? 1 : 0) != 0;
+
+  RefPtr<Selection> selection =
+      aPresShell->GetSelection(nsISelectionController::SELECTION_NORMAL);
+  if (!selection) {
+    return NS_ERROR_FAILURE;
+  }
+
+  selection->AddSelectionListener(this);
+  mDomSelectionWeak = selection;
+
+  return NS_OK;
+}
+
+static bool DrawCJKCaret(nsIFrame* aFrame, int32_t aOffset) {
+  nsIContent* content = aFrame->GetContent();
+  const nsTextFragment* frag = content->GetText();
+  if (!frag) {
+    return false;
+  }
+  if (aOffset < 0 || static_cast<uint32_t>(aOffset) >= frag->GetLength()) {
+    return false;
+  }
+  const char16_t ch = frag->CharAt(AssertedCast<uint32_t>(aOffset));
+  return 0x2e80 <= ch && ch <= 0xd7ff;
+}
+
+nsCaret::Metrics nsCaret::ComputeMetrics(nsIFrame* aFrame, int32_t aOffset,
+                                         nscoord aCaretHeight) {
+  // Compute nominal sizes in appunits
+  nscoord caretWidth =
+      (aCaretHeight *
+       LookAndFeel::GetFloat(LookAndFeel::FloatID::CaretAspectRatio, 0.0f)) +
+      nsPresContext::CSSPixelsToAppUnits(
+          LookAndFeel::GetInt(LookAndFeel::IntID::CaretWidth, 1));
+
+  if (DrawCJKCaret(aFrame, aOffset)) {
+    caretWidth += nsPresContext::CSSPixelsToAppUnits(1);
+  }
+  nscoord bidiIndicatorSize =
+      nsPresContext::CSSPixelsToAppUnits(kMinBidiIndicatorPixels);
+  bidiIndicatorSize = std::max(caretWidth, bidiIndicatorSize);
+
+  // Round them to device pixels. Always round down, except that anything
+  // between 0 and 1 goes up to 1 so we don't let the caret disappear.
+  int32_t tpp = aFrame->PresContext()->AppUnitsPerDevPixel();
+  Metrics result;
+  result.mCaretWidth = NS_ROUND_BORDER_TO_PIXELS(caretWidth, tpp);
+  result.mBidiIndicatorSize = NS_ROUND_BORDER_TO_PIXELS(bidiIndicatorSize, tpp);
+  return result;
+}
+
+void nsCaret::Terminate() {
+  // this doesn't erase the caret if it's drawn. Should it? We might not have
+  // a good drawing environment during teardown.
+
+  StopBlinking();
+  mBlinkTimer = nullptr;
+
+  // unregiser ourselves as a selection listener
+  if (mDomSelectionWeak) {
+    mDomSelectionWeak->RemoveSelectionListener(this);
+  }
+  mDomSelectionWeak = nullptr;
+  mPresShell = nullptr;
+
+  mOverrideContent = nullptr;
+}
+
+NS_IMPL_ISUPPORTS(nsCaret, nsISelectionListener)
+
+Selection* nsCaret::GetSelection() { return mDomSelectionWeak; }
+
+void nsCaret::SetSelection(Selection* aDOMSel) {
+  MOZ_ASSERT(aDOMSel);
+  mDomSelectionWeak = aDOMSel;
+  ResetBlinking();
+  SchedulePaint(aDOMSel);
+}
+
+void nsCaret::SetVisible(bool inMakeVisible) {
+  mVisible = inMakeVisible;
+  mIgnoreUserModify = mVisible;
+  ResetBlinking();
+  SchedulePaint();
+}
+
+void nsCaret::AddForceHide() {
+  MOZ_ASSERT(mHideCount < UINT32_MAX);
+  if (++mHideCount > 1) {
+    return;
+  }
+  ResetBlinking();
+  SchedulePaint();
+}
+
+void nsCaret::RemoveForceHide() {
+  if (!mHideCount || --mHideCount) {
+    return;
+  }
+  ResetBlinking();
+  SchedulePaint();
+}
+
+void nsCaret::SetCaretReadOnly(bool inMakeReadonly) {
+  mReadOnly = inMakeReadonly;
+  ResetBlinking();
+  SchedulePaint();
+}
+
+/* static */
+nsRect nsCaret::GetGeometryForFrame(nsIFrame* aFrame, int32_t aFrameOffset,
+                                    nscoord* aBidiIndicatorSize) {
+  nsPoint framePos(0, 0);
+  nsRect rect;
+  nsresult rv = aFrame->GetPointFromOffset(aFrameOffset, &framePos);
+  if (NS_FAILED(rv)) {
+    if (aBidiIndicatorSize) {
+      *aBidiIndicatorSize = 0;
+    }
+    return rect;
+  }
+
+  nsIFrame* frame = aFrame->GetContentInsertionFrame();
+  if (!frame) {
+    frame = aFrame;
+  }
+  NS_ASSERTION(!frame->HasAnyStateBits(NS_FRAME_IN_REFLOW),
+               "We should not be in the middle of reflow");
+  nscoord baseline = frame->GetCaretBaseline();
+  nscoord ascent = 0, descent = 0;
+  RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame);
+  NS_ASSERTION(fm, "We should be able to get the font metrics");
+  if (fm) {
+    ascent = fm->MaxAscent();
+    descent = fm->MaxDescent();
+  }
+  nscoord height = ascent + descent;
+  WritingMode wm = aFrame->GetWritingMode();
+  bool vertical = wm.IsVertical();
+  if (vertical) {
+    if (wm.IsLineInverted()) {
+      framePos.x = baseline - descent;
+    } else {
+      framePos.x = baseline - ascent;
+    }
+  } else {
+    framePos.y = baseline - ascent;
+  }
+  Metrics caretMetrics = ComputeMetrics(aFrame, aFrameOffset, height);
+
+  nsTextFrame* textFrame = do_QueryFrame(aFrame);
+  if (textFrame) {
+    gfxTextRun* textRun =
+        textFrame->GetTextRun(nsTextFrame::TextRunType::eInflated);
+    if (textRun) {
+      // For "upstream" text where the textrun direction is reversed from the
+      // frame's inline-dir we want the caret to be painted before rather than
+      // after its nominal inline position, so we offset by its width.
+      bool textRunDirIsReverseOfFrame =
+          wm.IsInlineReversed() != textRun->IsInlineReversed();
+      // However, in sideways-lr mode we invert this behavior because this is
+      // the one writing mode where bidi-LTR corresponds to inline-reversed
+      // already, which reverses the desired caret placement behavior.
+      // Note that the following condition is equivalent to:
+      //   if ( (!textRun->IsSidewaysLeft() && textRunDirIsReverseOfFrame) ||
+      //        (textRun->IsSidewaysLeft()  && !textRunDirIsReverseOfFrame) )
+      if (textRunDirIsReverseOfFrame != textRun->IsSidewaysLeft()) {
+        int dir = wm.IsBidiLTR() ? -1 : 1;
+        if (vertical) {
+          framePos.y += dir * caretMetrics.mCaretWidth;
+        } else {
+          framePos.x += dir * caretMetrics.mCaretWidth;
+        }
+      }
+    }
+  }
+
+  rect = nsRect(framePos, vertical ? nsSize(height, caretMetrics.mCaretWidth)
+                                   : nsSize(caretMetrics.mCaretWidth, height));
+
+  // Clamp the inline-position to be within our scroll frame. If we don't, then
+  // it clips us, and we don't appear at all. See bug 335560.
+
+  // Find the ancestor scroll frame and determine whether we have any transforms
+  // up the ancestor chain.
+  bool hasTransform = false;
+  nsIFrame* scrollFrame = nullptr;
+  for (nsIFrame* f = aFrame; f; f = f->GetParent()) {
+    if (f->IsScrollFrame()) {
+      scrollFrame = f;
+      break;
+    }
+    if (f->IsTransformed()) {
+      hasTransform = true;
+    }
+  }
+
+  // FIXME(heycam): Skip clamping if we find any transform up the ancestor
+  // chain, since the GetOffsetTo call below doesn't take transforms into
+  // account. We could change this clamping to take transforms into account, but
+  // the clamping seems to be broken anyway; see bug 1539720.
+  if (scrollFrame && !hasTransform) {
+    // First, use the scrollFrame to get at the scrollable view that we're in.
+    nsIScrollableFrame* sf = do_QueryFrame(scrollFrame);
+    nsIFrame* scrolled = sf->GetScrolledFrame();
+    nsRect caretInScroll = rect + aFrame->GetOffsetTo(scrolled);
+
+    // Now see if the caret extends beyond the view's bounds. If it does,
+    // then snap it back, put it as close to the edge as it can.
+    if (vertical) {
+      nscoord overflow = caretInScroll.YMost() -
+                         scrolled->InkOverflowRectRelativeToSelf().height;
+      if (overflow > 0) {
+        rect.y -= overflow;
+      }
+    } else {
+      nscoord overflow = caretInScroll.XMost() -
+                         scrolled->InkOverflowRectRelativeToSelf().width;
+      if (overflow > 0) {
+        rect.x -= overflow;
+      }
+    }
+  }
+
+  if (aBidiIndicatorSize) {
+    *aBidiIndicatorSize = caretMetrics.mBidiIndicatorSize;
+  }
+  return rect;
+}
+
+nsIFrame* nsCaret::GetFrameAndOffset(const Selection* aSelection,
+                                     nsINode* aOverrideNode,
+                                     int32_t aOverrideOffset,
+                                     int32_t* aFrameOffset,
+                                     nsIFrame** aUnadjustedFrame) {
+  if (aUnadjustedFrame) {
+    *aUnadjustedFrame = nullptr;
+  }
+
+  nsINode* focusNode;
+  int32_t focusOffset;
+
+  if (aOverrideNode) {
+    focusNode = aOverrideNode;
+    focusOffset = aOverrideOffset;
+  } else if (aSelection) {
+    focusNode = aSelection->GetFocusNode();
+    focusOffset = aSelection->FocusOffset();
+  } else {
+    return nullptr;
+  }
+
+  if (!focusNode || !focusNode->IsContent() || !aSelection) {
+    return nullptr;
+  }
+
+  nsIContent* contentNode = focusNode->AsContent();
+  nsFrameSelection* frameSelection = aSelection->GetFrameSelection();
+  BidiEmbeddingLevel bidiLevel = frameSelection->GetCaretBidiLevel();
+
+  return nsCaret::GetCaretFrameForNodeOffset(
+      frameSelection, contentNode, focusOffset, frameSelection->GetHint(),
+      bidiLevel, aUnadjustedFrame, aFrameOffset);
+}
+
+/* static */
+nsIFrame* nsCaret::GetGeometry(const Selection* aSelection, nsRect* aRect) {
+  int32_t frameOffset;
+  nsIFrame* frame = GetFrameAndOffset(aSelection, nullptr, 0, &frameOffset);
+  if (frame) {
+    *aRect = GetGeometryForFrame(frame, frameOffset, nullptr);
+  }
+  return frame;
+}
+
+[[nodiscard]] static nsIFrame* GetContainingBlockIfNeeded(nsIFrame* aFrame) {
+  if (aFrame->IsBlockOutside() || aFrame->IsBlockFrameOrSubclass()) {
+    return nullptr;
+  }
+  return aFrame->GetContainingBlock();
+}
+
+void nsCaret::SchedulePaint(Selection* aSelection) {
+  Selection* selection;
+  if (aSelection) {
+    selection = aSelection;
+  } else {
+    selection = GetSelection();
+  }
+
+  int32_t frameOffset;
+  nsIFrame* frame = GetFrameAndOffset(selection, mOverrideContent,
+                                      mOverrideOffset, &frameOffset);
+  if (!frame) {
+    return;
+  }
+
+  if (nsIFrame* cb = GetContainingBlockIfNeeded(frame)) {
+    cb->SchedulePaint();
+  } else {
+    frame->SchedulePaint();
+  }
+}
+
+void nsCaret::SetVisibilityDuringSelection(bool aVisibility) {
+  mShowDuringSelection = aVisibility;
+  SchedulePaint();
+}
+
+void nsCaret::SetCaretPosition(nsINode* aNode, int32_t aOffset) {
+  mOverrideContent = aNode;
+  mOverrideOffset = aOffset;
+
+  ResetBlinking();
+  SchedulePaint();
+}
+
+void nsCaret::CheckSelectionLanguageChange() {
+  if (!IsBidiUI()) {
+    return;
+  }
+
+  bool isKeyboardRTL = false;
+  nsIBidiKeyboard* bidiKeyboard = nsContentUtils::GetBidiKeyboard();
+  if (bidiKeyboard) {
+    bidiKeyboard->IsLangRTL(&isKeyboardRTL);
+  }
+  // Call SelectionLanguageChange on every paint. Mostly it will be a noop
+  // but it should be fast anyway. This guarantees we never paint the caret
+  // at the wrong place.
+  Selection* selection = GetSelection();
+  if (selection) {
+    selection->SelectionLanguageChange(isKeyboardRTL);
+  }
+}
+
+// This ensures that the caret is not affected by clips on inlines and so forth.
+[[nodiscard]] static nsIFrame* MapToContainingBlock(nsIFrame* aFrame,
+                                                    nsRect* aCaretRect,
+                                                    nsRect* aHookRect) {
+  nsIFrame* containingBlock = GetContainingBlockIfNeeded(aFrame);
+  if (!containingBlock) {
+    return aFrame;
+  }
+
+  *aCaretRect = nsLayoutUtils::TransformFrameRectToAncestor(aFrame, *aCaretRect,
+                                                            containingBlock);
+  *aHookRect = nsLayoutUtils::TransformFrameRectToAncestor(aFrame, *aHookRect,
+                                                           containingBlock);
+  return containingBlock;
+}
+
+nsIFrame* nsCaret::GetPaintGeometry(nsRect* aCaretRect, nsRect* aHookRect,
+                                    nscolor* aCaretColor) {
+  // Return null if we should not be visible.
+  if (!IsVisible() || !mIsBlinkOn) {
+    return nullptr;
+  }
+
+  // Update selection language direction now so the new direction will be
+  // taken into account when computing the caret position below.
+  CheckSelectionLanguageChange();
+
+  int32_t frameOffset;
+  nsIFrame* unadjustedFrame = nullptr;
+  nsIFrame* frame =
+      GetFrameAndOffset(GetSelection(), mOverrideContent, mOverrideOffset,
+                        &frameOffset, &unadjustedFrame);
+  MOZ_ASSERT(!!frame == !!unadjustedFrame);
+  if (!frame) {
+    return nullptr;
+  }
+
+  // Now we have a frame, check whether it's appropriate to show the caret here.
+  // Note we need to check the unadjusted frame, otherwise consider the
+  // following case:
+  //
+  //   <div contenteditable><span contenteditable=false>Text   </span><br>
+  //
+  // Where the selection is targeting the <br>. We want to display the caret,
+  // since the <br> we're focused at is editable, but we do want to paint it at
+  // the adjusted frame offset, so that we can see the collapsed whitespace.
+  const nsStyleUI* ui = unadjustedFrame->StyleUI();
+  if ((!mIgnoreUserModify && ui->UserModify() == StyleUserModify::ReadOnly) ||
+      unadjustedFrame->IsContentDisabled()) {
+    return nullptr;
+  }
+
+  // If the offset falls outside of the frame, then don't paint the caret.
+  if (frame->IsTextFrame()) {
+    auto [startOffset, endOffset] = frame->GetOffsets();
+    if (startOffset > frameOffset || endOffset < frameOffset) {
+      return nullptr;
+    }
+  }
+
+  if (aCaretColor) {
+    *aCaretColor = frame->GetCaretColorAt(frameOffset);
+  }
+
+  ComputeCaretRects(frame, frameOffset, aCaretRect, aHookRect);
+  return MapToContainingBlock(frame, aCaretRect, aHookRect);
+}
+
+nsIFrame* nsCaret::GetPaintGeometry(nsRect* aRect) {
+  nsRect caretRect;
+  nsRect hookRect;
+  nsIFrame* frame = GetPaintGeometry(&caretRect, &hookRect);
+  aRect->UnionRect(caretRect, hookRect);
+  return frame;
+}
+
+void nsCaret::PaintCaret(DrawTarget& aDrawTarget, nsIFrame* aForFrame,
+                         const nsPoint& aOffset) {
+  nsRect caretRect;
+  nsRect hookRect;
+  nscolor color;
+  nsIFrame* frame = GetPaintGeometry(&caretRect, &hookRect, &color);
+  MOZ_ASSERT(frame == aForFrame, "We're referring different frame");
+
+  if (!frame) {
+    return;
+  }
+
+  int32_t appUnitsPerDevPixel = frame->PresContext()->AppUnitsPerDevPixel();
+  Rect devPxCaretRect = NSRectToSnappedRect(caretRect + aOffset,
+                                            appUnitsPerDevPixel, aDrawTarget);
+  Rect devPxHookRect =
+      NSRectToSnappedRect(hookRect + aOffset, appUnitsPerDevPixel, aDrawTarget);
+
+  ColorPattern pattern(ToDeviceColor(color));
+  aDrawTarget.FillRect(devPxCaretRect, pattern);
+  if (!hookRect.IsEmpty()) {
+    aDrawTarget.FillRect(devPxHookRect, pattern);
+  }
+}
+
+NS_IMETHODIMP
+nsCaret::NotifySelectionChanged(Document*, Selection* aDomSel, int16_t aReason,
+                                int32_t aAmount) {
+  // Note that aDomSel, per the comment below may not be the same as our
+  // selection, but that's OK since if that is the case, it wouldn't have
+  // mattered what IsVisible() returns here, so we just opt for checking
+  // the selection later down below.
+  if ((aReason & nsISelectionListener::MOUSEUP_REASON) ||
+      !IsVisible(aDomSel))  // this wont do
+    return NS_OK;
+
+  // The same caret is shared amongst the document and any text widgets it
+  // may contain. This means that the caret could get notifications from
+  // multiple selections.
+  //
+  // If this notification is for a selection that is not the one the
+  // the caret is currently interested in (mDomSelectionWeak), then there
+  // is nothing to do!
+
+  if (mDomSelectionWeak != aDomSel) return NS_OK;
+
+  ResetBlinking();
+  SchedulePaint(aDomSel);
+
+  return NS_OK;
+}
+
+void nsCaret::ResetBlinking() {
+  using IntID = LookAndFeel::IntID;
+
+  // The default caret blinking rate (in ms of blinking interval)
+  constexpr uint32_t kDefaultBlinkRate = 500;
+  // The default caret blinking count (-1 for "never stop blinking")
+  constexpr int32_t kDefaultBlinkCount = -1;
+
+  mIsBlinkOn = true;
+
+  if (mReadOnly || !mVisible || mHideCount) {
+    StopBlinking();
+    return;
+  }
+
+  auto blinkRate =
+      uint32_t(LookAndFeel::GetInt(IntID::CaretBlinkTime, kDefaultBlinkRate));
+
+  if (blinkRate > 0) {
+    // Make sure to reset the remaining blink count even if the blink rate
+    // hasn't changed.
+    mBlinkCount =
+        LookAndFeel::GetInt(IntID::CaretBlinkCount, kDefaultBlinkCount);
+  }
+
+  if (mBlinkRate == blinkRate) {
+    // If the rate hasn't changed, then there is nothing else to do.
+    return;
+  }
+
+  mBlinkRate = blinkRate;
+
+  if (mBlinkTimer) {
+    mBlinkTimer->Cancel();
+  } else {
+    nsIEventTarget* target = nullptr;
+    if (RefPtr<PresShell> presShell = do_QueryReferent(mPresShell)) {
+      if (nsCOMPtr<Document> doc = presShell->GetDocument()) {
+        target = doc->EventTargetFor(TaskCategory::Other);
+      }
+    }
+
+    mBlinkTimer = NS_NewTimer(target);
+    if (!mBlinkTimer) {
+      return;
+    }
+  }
+
+  if (blinkRate > 0) {
+    mBlinkTimer->InitWithNamedFuncCallback(CaretBlinkCallback, this, blinkRate,
+                                           nsITimer::TYPE_REPEATING_SLACK,
+                                           "nsCaret::CaretBlinkCallback_timer");
+  }
+}
+
+void nsCaret::StopBlinking() {
+  if (mBlinkTimer) {
+    mBlinkTimer->Cancel();
+    mBlinkRate = 0;
+  }
+}
+
+nsIFrame* nsCaret::GetCaretFrameForNodeOffset(nsFrameSelection* aFrameSelection,
+                                              nsIContent* aContentNode,
+                                              int32_t aOffset,
+                                              CaretAssociationHint aFrameHint,
+                                              BidiEmbeddingLevel aBidiLevel,
+                                              nsIFrame** aReturnUnadjustedFrame,
+                                              int32_t* aReturnOffset) {
+  if (!aFrameSelection) {
+    return nullptr;
+  }
+
+  PresShell* presShell = aFrameSelection->GetPresShell();
+  if (!presShell) {
+    return nullptr;
+  }
+
+  if (!aContentNode || !aContentNode->IsInComposedDoc() ||
+      presShell->GetDocument() != aContentNode->GetComposedDoc()) {
+    return nullptr;
+  }
+
+  nsIFrame* theFrame = nullptr;
+  int32_t theFrameOffset = 0;
+
+  theFrame = nsFrameSelection::GetFrameForNodeOffset(
+      aContentNode, aOffset, aFrameHint, &theFrameOffset);
+  if (!theFrame) {
+    return nullptr;
+  }
+
+  if (aReturnUnadjustedFrame) {
+    *aReturnUnadjustedFrame = theFrame;
+  }
+
+  if (nsFrameSelection::AdjustFrameForLineStart(theFrame, theFrameOffset)) {
+    aFrameSelection->SetHint(CARET_ASSOCIATE_AFTER);
+  } else {
+    // if theFrame is after a text frame that's logically at the end of the line
+    // (e.g. if theFrame is a <br> frame), then put the caret at the end of
+    // that text frame instead. This way, the caret will be positioned as if
+    // trailing whitespace was not trimmed.
+    AdjustCaretFrameForLineEnd(&theFrame, &theFrameOffset);
+  }
+
+  // Mamdouh : modification of the caret to work at rtl and ltr with Bidi
+  //
+  // Direction Style from visibility->mDirection
+  // ------------------
+  if (theFrame->PresContext()->BidiEnabled()) {
+    // If there has been a reflow, take the caret Bidi level to be the level of
+    // the current frame
+    if (aBidiLevel & BIDI_LEVEL_UNDEFINED) {
+      aBidiLevel = theFrame->GetEmbeddingLevel();
+    }
+
+    nsIFrame* frameBefore;
+    nsIFrame* frameAfter;
+    BidiEmbeddingLevel
+        levelBefore;  // Bidi level of the character before the caret
+    BidiEmbeddingLevel
+        levelAfter;  // Bidi level of the character after the caret
+
+    auto [start, end] = theFrame->GetOffsets();
+    if (start == 0 || end == 0 || start == theFrameOffset ||
+        end == theFrameOffset) {
+      nsPrevNextBidiLevels levels =
+          aFrameSelection->GetPrevNextBidiLevels(aContentNode, aOffset, false);
+
+      /* Boundary condition, we need to know the Bidi levels of the characters
+       * before and after the caret */
+      if (levels.mFrameBefore || levels.mFrameAfter) {
+        frameBefore = levels.mFrameBefore;
+        frameAfter = levels.mFrameAfter;
+        levelBefore = levels.mLevelBefore;
+        levelAfter = levels.mLevelAfter;
+
+        if ((levelBefore != levelAfter) || (aBidiLevel != levelBefore)) {
+          aBidiLevel = std::max(aBidiLevel,
+                                std::min(levelBefore, levelAfter));  // rule c3
+          aBidiLevel = std::min(aBidiLevel,
+                                std::max(levelBefore, levelAfter));  // rule c4
+          if (aBidiLevel == levelBefore ||                           // rule c1
+              (aBidiLevel > levelBefore && aBidiLevel < levelAfter &&
+               aBidiLevel.IsSameDirection(levelBefore)) ||  // rule c5
+              (aBidiLevel < levelBefore && aBidiLevel > levelAfter &&
+               aBidiLevel.IsSameDirection(levelBefore)))  // rule c9
+          {
+            if (theFrame != frameBefore) {
+              if (frameBefore) {  // if there is a frameBefore, move into it
+                theFrame = frameBefore;
+                std::tie(start, end) = theFrame->GetOffsets();
+                theFrameOffset = end;
+              } else {
+                // if there is no frameBefore, we must be at the beginning of
+                // the line so we stay with the current frame. Exception: when
+                // the first frame on the line has a different Bidi level from
+                // the paragraph level, there is no real frame for the caret to
+                // be in. We have to find the visually first frame on the line.
+                BidiEmbeddingLevel baseLevel = frameAfter->GetBaseLevel();
+                if (baseLevel != levelAfter) {
+                  nsPeekOffsetStruct pos(eSelectBeginLine, eDirPrevious, 0,
+                                         nsPoint(0, 0), false, true, false,
+                                         true, false);
+                  if (NS_SUCCEEDED(frameAfter->PeekOffset(&pos))) {
+                    theFrame = pos.mResultFrame;
+                    theFrameOffset = pos.mContentOffset;
+                  }
+                }
+              }
+            }
+          } else if (aBidiLevel == levelAfter ||  // rule c2
+                     (aBidiLevel > levelBefore && aBidiLevel < levelAfter &&
+                      aBidiLevel.IsSameDirection(levelAfter)) ||  // rule c6
+                     (aBidiLevel < levelBefore && aBidiLevel > levelAfter &&
+                      aBidiLevel.IsSameDirection(levelAfter)))  // rule c10
+          {
+            if (theFrame != frameAfter) {
+              if (frameAfter) {
+                // if there is a frameAfter, move into it
+                theFrame = frameAfter;
+                std::tie(start, end) = theFrame->GetOffsets();
+                theFrameOffset = start;
+              } else {
+                // if there is no frameAfter, we must be at the end of the line
+                // so we stay with the current frame.
+                // Exception: when the last frame on the line has a different
+                // Bidi level from the paragraph level, there is no real frame
+                // for the caret to be in. We have to find the visually last
+                // frame on the line.
+                BidiEmbeddingLevel baseLevel = frameBefore->GetBaseLevel();
+                if (baseLevel != levelBefore) {
+                  nsPeekOffsetStruct pos(eSelectEndLine, eDirNext, 0,
+                                         nsPoint(0, 0), false, true, false,
+                                         true, false);
+                  if (NS_SUCCEEDED(frameBefore->PeekOffset(&pos))) {
+                    theFrame = pos.mResultFrame;
+                    theFrameOffset = pos.mContentOffset;
+                  }
+                }
+              }
+            }
+          } else if (aBidiLevel > levelBefore &&
+                     aBidiLevel < levelAfter &&  // rule c7/8
+                     // before and after have the same parity
+                     levelBefore.IsSameDirection(levelAfter) &&
+                     // caret has different parity
+                     !aBidiLevel.IsSameDirection(levelAfter)) {
+            if (NS_SUCCEEDED(aFrameSelection->GetFrameFromLevel(
+                    frameAfter, eDirNext, aBidiLevel, &theFrame))) {
+              std::tie(start, end) = theFrame->GetOffsets();
+              levelAfter = theFrame->GetEmbeddingLevel();
+              if (aBidiLevel.IsRTL()) {
+                // c8: caret to the right of the rightmost character
+                theFrameOffset = levelAfter.IsRTL() ? start : end;
+              } else {
+                // c7: caret to the left of the leftmost character
+                theFrameOffset = levelAfter.IsRTL() ? end : start;
+              }
+            }
+          } else if (aBidiLevel < levelBefore &&
+                     aBidiLevel > levelAfter &&  // rule c11/12
+                     // before and after have the same parity
+                     levelBefore.IsSameDirection(levelAfter) &&
+                     // caret has different parity
+                     !aBidiLevel.IsSameDirection(levelAfter)) {
+            if (NS_SUCCEEDED(aFrameSelection->GetFrameFromLevel(
+                    frameBefore, eDirPrevious, aBidiLevel, &theFrame))) {
+              std::tie(start, end) = theFrame->GetOffsets();
+              levelBefore = theFrame->GetEmbeddingLevel();
+              if (aBidiLevel.IsRTL()) {
+                // c12: caret to the left of the leftmost character
+                theFrameOffset = levelBefore.IsRTL() ? end : start;
+              } else {
+                // c11: caret to the right of the rightmost character
+                theFrameOffset = levelBefore.IsRTL() ? start : end;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  *aReturnOffset = theFrameOffset;
+  return theFrame;
+}
+
+size_t nsCaret::SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
+  size_t total = aMallocSizeOf(this);
+  if (mPresShell) {
+    // We only want the size of the nsWeakReference object, not the PresShell
+    // (since we don't own the PresShell).
+    total += mPresShell->SizeOfOnlyThis(aMallocSizeOf);
+  }
+  if (mBlinkTimer) {
+    total += mBlinkTimer->SizeOfIncludingThis(aMallocSizeOf);
+  }
+  return total;
+}
+
+bool nsCaret::IsMenuPopupHidingCaret() {
+  // Check if there are open popups.
+  nsXULPopupManager* popMgr = nsXULPopupManager::GetInstance();
+  nsTArray<nsIFrame*> popups;
+  popMgr->GetVisiblePopups(popups);
+
+  if (popups.Length() == 0)
+    return false;  // No popups, so caret can't be hidden by them.
+
+  // Get the selection focus content, that's where the caret would
+  // go if it was drawn.
+  if (!mDomSelectionWeak) {
+    return true;  // No selection/caret to draw.
+  }
+  nsCOMPtr<nsIContent> caretContent =
+      nsIContent::FromNodeOrNull(mDomSelectionWeak->GetFocusNode());
+  if (!caretContent) return true;  // No selection/caret to draw.
+
+  // If there's a menu popup open before the popup with
+  // the caret, don't show the caret.
+  for (uint32_t i = 0; i < popups.Length(); i++) {
+    nsMenuPopupFrame* popupFrame = static_cast<nsMenuPopupFrame*>(popups[i]);
+    nsIContent* popupContent = popupFrame->GetContent();
+
+    if (caretContent->IsInclusiveDescendantOf(popupContent)) {
+      // The caret is in this popup. There were no menu popups before this
+      // popup, so don't hide the caret.
+      return false;
+    }
+
+    if (popupFrame->PopupType() == ePopupTypeMenu &&
+        !popupFrame->IsContextMenu()) {
+      // This is an open menu popup. It does not contain the caret (else we'd
+      // have returned above). Even if the caret is in a subsequent popup,
+      // or another document/frame, it should be hidden.
+      return true;
+    }
+  }
+
+  // There are no open menu popups, no need to hide the caret.
+  return false;
+}
+
+void nsCaret::ComputeCaretRects(nsIFrame* aFrame, int32_t aFrameOffset,
+                                nsRect* aCaretRect, nsRect* aHookRect) {
+  NS_ASSERTION(aFrame, "Should have a frame here");
+
+  WritingMode wm = aFrame->GetWritingMode();
+  bool isVertical = wm.IsVertical();
+
+  nscoord bidiIndicatorSize;
+  *aCaretRect = GetGeometryForFrame(aFrame, aFrameOffset, &bidiIndicatorSize);
+
+  // on RTL frames the right edge of mCaretRect must be equal to framePos
+  const nsStyleVisibility* vis = aFrame->StyleVisibility();
+  if (StyleDirection::Rtl == vis->mDirection) {
+    if (isVertical) {
+      aCaretRect->y -= aCaretRect->height;
+    } else {
+      aCaretRect->x -= aCaretRect->width;
+    }
+  }
+
+  // Simon -- make a hook to draw to the left or right of the caret to show
+  // keyboard language direction
+  aHookRect->SetEmpty();
+  if (!IsBidiUI()) {
+    return;
+  }
+
+  bool isCaretRTL;
+  nsIBidiKeyboard* bidiKeyboard = nsContentUtils::GetBidiKeyboard();
+  // if bidiKeyboard->IsLangRTL() fails, there is no way to tell the
+  // keyboard direction, or the user has no right-to-left keyboard
+  // installed, so we never draw the hook.
+  if (bidiKeyboard && NS_SUCCEEDED(bidiKeyboard->IsLangRTL(&isCaretRTL))) {
+    // If keyboard language is RTL, draw the hook on the left; if LTR, to the
+    // right The height of the hook rectangle is the same as the width of the
+    // caret rectangle.
+    if (isVertical) {
+      if (wm.IsSidewaysLR()) {
+        aHookRect->SetRect(aCaretRect->x + bidiIndicatorSize,
+                           aCaretRect->y + (!isCaretRTL ? bidiIndicatorSize * -1
+                                                        : aCaretRect->height),
+                           aCaretRect->height, bidiIndicatorSize);
+      } else {
+        aHookRect->SetRect(aCaretRect->XMost() - bidiIndicatorSize,
+                           aCaretRect->y + (isCaretRTL ? bidiIndicatorSize * -1
+                                                       : aCaretRect->height),
+                           aCaretRect->height, bidiIndicatorSize);
+      }
+    } else {
+      aHookRect->SetRect(aCaretRect->x + (isCaretRTL ? bidiIndicatorSize * -1
+                                                     : aCaretRect->width),
+                         aCaretRect->y + bidiIndicatorSize, bidiIndicatorSize,
+                         aCaretRect->width);
+    }
+  }
+}
+
+/* static */
+void nsCaret::CaretBlinkCallback(nsITimer* aTimer, void* aClosure) {
+  nsCaret* theCaret = reinterpret_cast<nsCaret*>(aClosure);
+  if (!theCaret) {
+    return;
+  }
+  theCaret->mIsBlinkOn = !theCaret->mIsBlinkOn;
+  theCaret->SchedulePaint();
+
+  // mBlinkCount of -1 means blink count is not enabled.
+  if (theCaret->mBlinkCount == -1) {
+    return;
+  }
+
+  // Track the blink count, but only at end of a blink cycle.
+  if (theCaret->mIsBlinkOn) {
+    // If we exceeded the blink count, stop the timer.
+    if (--theCaret->mBlinkCount <= 0) {
+      theCaret->StopBlinking();
+    }
+  }
+}
+
+void nsCaret::SetIgnoreUserModify(bool aIgnoreUserModify) {
+  mIgnoreUserModify = aIgnoreUserModify;
+  SchedulePaint();
+}