Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

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

1 files changed, 1209 insertions, 0 deletions

diff --git a/editor/libeditor/HTMLEditHelpers.h b/editor/libeditor/HTMLEditHelpers.h
new file mode 100644
index 0000000000..499bd82f00
--- /dev/null
+++ b/editor/libeditor/HTMLEditHelpers.h
@@ -0,0 +1,1209 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#ifndef HTMLEditHelpers_h
+#define HTMLEditHelpers_h
+
+/**
+ * This header declares/defines trivial helper classes which are used by
+ * HTMLEditor.  If you want to create or look for static utility methods,
+ * see HTMLEditUtils.h.
+ */
+
+#include "EditorDOMPoint.h"
+#include "EditorForwards.h"
+#include "EditorUtils.h"  // for CaretPoint
+#include "HTMLEditHelpers.h"
+#include "JoinSplitNodeDirection.h"
+
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/ContentIterator.h"
+#include "mozilla/IntegerRange.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/RangeBoundary.h"
+#include "mozilla/Result.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/StaticRange.h"
+
+#include "nsCOMPtr.h"
+#include "nsDebug.h"
+#include "nsError.h"
+#include "nsGkAtoms.h"
+#include "nsIContent.h"
+#include "nsRange.h"
+#include "nsString.h"
+
+class nsISimpleEnumerator;
+
+namespace mozilla {
+
+enum class WithTransaction { No, Yes };
+inline std::ostream& operator<<(std::ostream& aStream,
+                                WithTransaction aWithTransaction) {
+  aStream << "WithTransaction::"
+          << (aWithTransaction == WithTransaction::Yes ? "Yes" : "No");
+  return aStream;
+}
+
+/*****************************************************************************
+ * MoveNodeResult is a simple class for MoveSomething() methods.
+ * This stores whether it's handled or not, and next insertion point and a
+ * suggestion for new caret position.
+ *****************************************************************************/
+class MOZ_STACK_CLASS MoveNodeResult final : public CaretPoint {
+ public:
+  constexpr bool Handled() const { return mHandled; }
+  constexpr bool Ignored() const { return !Handled(); }
+  constexpr const EditorDOMPoint& NextInsertionPointRef() const {
+    return mNextInsertionPoint;
+  }
+  constexpr EditorDOMPoint&& UnwrapNextInsertionPoint() {
+    return std::move(mNextInsertionPoint);
+  }
+  template <typename EditorDOMPointType>
+  EditorDOMPointType NextInsertionPoint() const {
+    return mNextInsertionPoint.To<EditorDOMPointType>();
+  }
+
+  /**
+   * Override the result as "handled" forcibly.
+   */
+  void MarkAsHandled() { mHandled = true; }
+
+  MoveNodeResult(const MoveNodeResult& aOther) = delete;
+  MoveNodeResult& operator=(const MoveNodeResult& aOther) = delete;
+  MoveNodeResult(MoveNodeResult&& aOther) = default;
+  MoveNodeResult& operator=(MoveNodeResult&& aOther) = default;
+
+  MoveNodeResult& operator|=(const MoveNodeResult& aOther) {
+    MOZ_ASSERT(this != &aOther);
+    // aOther is merged with this instance so that its caret suggestion
+    // shouldn't be handled anymore.
+    aOther.IgnoreCaretPointSuggestion();
+    // Should be handled again even if it's already handled
+    UnmarkAsHandledCaretPoint();
+
+    mHandled |= aOther.mHandled;
+
+    // Take the new one for the next insertion point.
+    mNextInsertionPoint = aOther.mNextInsertionPoint;
+
+    // Take the new caret point if and only if it's suggested.
+    if (aOther.HasCaretPointSuggestion()) {
+      SetCaretPoint(aOther.CaretPointRef());
+    }
+    return *this;
+  }
+
+#ifdef DEBUG
+  ~MoveNodeResult() {
+    MOZ_ASSERT_IF(Handled(), !HasCaretPointSuggestion() || CaretPointHandled());
+  }
+#endif
+
+  /*****************************************************************************
+   * When a move node handler (or its helper) does nothing,
+   * the result of these factory methods should be returned.
+   * aNextInsertionPoint Must be set and valid.
+   *****************************************************************************/
+  static MoveNodeResult IgnoredResult(
+      const EditorDOMPoint& aNextInsertionPoint) {
+    return MoveNodeResult(aNextInsertionPoint, false);
+  }
+  static MoveNodeResult IgnoredResult(EditorDOMPoint&& aNextInsertionPoint) {
+    return MoveNodeResult(std::move(aNextInsertionPoint), false);
+  }
+
+  /*****************************************************************************
+   * When a move node handler (or its helper) handled and not canceled,
+   * the result of these factory methods should be returned.
+   * aNextInsertionPoint Must be set and valid.
+   *****************************************************************************/
+  static MoveNodeResult HandledResult(
+      const EditorDOMPoint& aNextInsertionPoint) {
+    return MoveNodeResult(aNextInsertionPoint, true);
+  }
+
+  static MoveNodeResult HandledResult(EditorDOMPoint&& aNextInsertionPoint) {
+    return MoveNodeResult(std::move(aNextInsertionPoint), true);
+  }
+
+  static MoveNodeResult HandledResult(const EditorDOMPoint& aNextInsertionPoint,
+                                      const EditorDOMPoint& aPointToPutCaret) {
+    return MoveNodeResult(aNextInsertionPoint, aPointToPutCaret);
+  }
+
+  static MoveNodeResult HandledResult(EditorDOMPoint&& aNextInsertionPoint,
+                                      const EditorDOMPoint& aPointToPutCaret) {
+    return MoveNodeResult(std::move(aNextInsertionPoint), aPointToPutCaret);
+  }
+
+  static MoveNodeResult HandledResult(const EditorDOMPoint& aNextInsertionPoint,
+                                      EditorDOMPoint&& aPointToPutCaret) {
+    return MoveNodeResult(aNextInsertionPoint, std::move(aPointToPutCaret));
+  }
+
+  static MoveNodeResult HandledResult(EditorDOMPoint&& aNextInsertionPoint,
+                                      EditorDOMPoint&& aPointToPutCaret) {
+    return MoveNodeResult(std::move(aNextInsertionPoint),
+                          std::move(aPointToPutCaret));
+  }
+
+ private:
+  explicit MoveNodeResult(const EditorDOMPoint& aNextInsertionPoint,
+                          bool aHandled)
+      : CaretPoint(),
+        mNextInsertionPoint(aNextInsertionPoint),
+        mHandled(aHandled && aNextInsertionPoint.IsSet()) {
+    AutoEditorDOMPointChildInvalidator computeOffsetAndForgetChild(
+        mNextInsertionPoint);
+  }
+  explicit MoveNodeResult(EditorDOMPoint&& aNextInsertionPoint, bool aHandled)
+      : CaretPoint(),
+        mNextInsertionPoint(std::move(aNextInsertionPoint)),
+        mHandled(aHandled && mNextInsertionPoint.IsSet()) {
+    AutoEditorDOMPointChildInvalidator computeOffsetAndForgetChild(
+        mNextInsertionPoint);
+  }
+  explicit MoveNodeResult(const EditorDOMPoint& aNextInsertionPoint,
+                          const EditorDOMPoint& aPointToPutCaret)
+      : CaretPoint(aPointToPutCaret),
+        mNextInsertionPoint(aNextInsertionPoint),
+        mHandled(mNextInsertionPoint.IsSet()) {
+    AutoEditorDOMPointChildInvalidator computeOffsetAndForgetChild(
+        mNextInsertionPoint);
+  }
+  explicit MoveNodeResult(EditorDOMPoint&& aNextInsertionPoint,
+                          const EditorDOMPoint& aPointToPutCaret)
+      : CaretPoint(aPointToPutCaret),
+        mNextInsertionPoint(std::move(aNextInsertionPoint)),
+        mHandled(mNextInsertionPoint.IsSet()) {
+    AutoEditorDOMPointChildInvalidator computeOffsetAndForgetChild(
+        mNextInsertionPoint);
+  }
+  explicit MoveNodeResult(const EditorDOMPoint& aNextInsertionPoint,
+                          EditorDOMPoint&& aPointToPutCaret)
+      : CaretPoint(std::move(aPointToPutCaret)),
+        mNextInsertionPoint(aNextInsertionPoint),
+        mHandled(mNextInsertionPoint.IsSet()) {
+    AutoEditorDOMPointChildInvalidator computeOffsetAndForgetChild(
+        mNextInsertionPoint);
+  }
+  explicit MoveNodeResult(EditorDOMPoint&& aNextInsertionPoint,
+                          EditorDOMPoint&& aPointToPutCaret)
+      : CaretPoint(std::move(aPointToPutCaret)),
+        mNextInsertionPoint(std::move(aNextInsertionPoint)),
+        mHandled(mNextInsertionPoint.IsSet()) {
+    AutoEditorDOMPointChildInvalidator computeOffsetAndForgetChild(
+        mNextInsertionPoint);
+  }
+
+  EditorDOMPoint mNextInsertionPoint;
+  bool mHandled;
+};
+
+/*****************************************************************************
+ * SplitNodeResult is a simple class for
+ * HTMLEditor::SplitNodeDeepWithTransaction().
+ * This makes the callers' code easier to read.
+ *****************************************************************************/
+class MOZ_STACK_CLASS SplitNodeResult final : public CaretPoint {
+ public:
+  bool Handled() const { return mPreviousNode || mNextNode; }
+
+  /**
+   * DidSplit() returns true if a node was actually split.
+   */
+  bool DidSplit() const { return mPreviousNode && mNextNode; }
+
+  /**
+   * GetPreviousContent() returns previous content node at the split point.
+   */
+  MOZ_KNOWN_LIVE nsIContent* GetPreviousContent() const {
+    if (mGivenSplitPoint.IsSet()) {
+      return mGivenSplitPoint.IsEndOfContainer() ? mGivenSplitPoint.GetChild()
+                                                 : nullptr;
+    }
+    return mPreviousNode;
+  }
+  template <typename NodeType>
+  MOZ_KNOWN_LIVE NodeType* GetPreviousContentAs() const {
+    return NodeType::FromNodeOrNull(GetPreviousContent());
+  }
+  template <typename EditorDOMPointType>
+  EditorDOMPointType AtPreviousContent() const {
+    if (nsIContent* previousContent = GetPreviousContent()) {
+      return EditorDOMPointType(previousContent);
+    }
+    return EditorDOMPointType();
+  }
+
+  /**
+   * GetNextContent() returns next content node at the split point.
+   */
+  MOZ_KNOWN_LIVE nsIContent* GetNextContent() const {
+    if (mGivenSplitPoint.IsSet()) {
+      return !mGivenSplitPoint.IsEndOfContainer() ? mGivenSplitPoint.GetChild()
+                                                  : nullptr;
+    }
+    return mNextNode;
+  }
+  template <typename NodeType>
+  MOZ_KNOWN_LIVE NodeType* GetNextContentAs() const {
+    return NodeType::FromNodeOrNull(GetNextContent());
+  }
+  template <typename EditorDOMPointType>
+  EditorDOMPointType AtNextContent() const {
+    if (nsIContent* nextContent = GetNextContent()) {
+      return EditorDOMPointType(nextContent);
+    }
+    return EditorDOMPointType();
+  }
+
+  /**
+   * Returns new content node which is created at splitting a node.  I.e., this
+   * returns nullptr if no node was split.
+   */
+  MOZ_KNOWN_LIVE nsIContent* GetNewContent() const {
+    if (!DidSplit()) {
+      return nullptr;
+    }
+    return mDirection == SplitNodeDirection::LeftNodeIsNewOne ? mPreviousNode
+                                                              : mNextNode;
+  }
+  template <typename NodeType>
+  MOZ_KNOWN_LIVE NodeType* GetNewContentAs() const {
+    return NodeType::FromNodeOrNull(GetNewContent());
+  }
+  template <typename EditorDOMPointType>
+  EditorDOMPointType AtNewContent() const {
+    if (nsIContent* newContent = GetNewContent()) {
+      return EditorDOMPointType(newContent);
+    }
+    return EditorDOMPointType();
+  }
+
+  /**
+   * Returns original content node which is (or is just tried to be) split.
+   */
+  MOZ_KNOWN_LIVE nsIContent* GetOriginalContent() const {
+    if (mGivenSplitPoint.IsSet()) {
+      // Different from previous/next content, if the creator didn't split a
+      // node, the container of the split point is the original node.
+      return mGivenSplitPoint.GetContainerAs<nsIContent>();
+    }
+    if (mDirection == SplitNodeDirection::LeftNodeIsNewOne) {
+      return mNextNode ? mNextNode : mPreviousNode;
+    }
+    return mPreviousNode ? mPreviousNode : mNextNode;
+  }
+  template <typename NodeType>
+  MOZ_KNOWN_LIVE NodeType* GetOriginalContentAs() const {
+    return NodeType::FromNodeOrNull(GetOriginalContent());
+  }
+  template <typename EditorDOMPointType>
+  EditorDOMPointType AtOriginalContent() const {
+    if (nsIContent* originalContent = GetOriginalContent()) {
+      return EditorDOMPointType(originalContent);
+    }
+    return EditorDOMPointType();
+  }
+
+  /**
+   * AtSplitPoint() returns the split point in the container.
+   * HTMLEditor::CreateAndInsertElement() or something similar methods.
+   */
+  template <typename EditorDOMPointType>
+  EditorDOMPointType AtSplitPoint() const {
+    if (mGivenSplitPoint.IsSet()) {
+      return mGivenSplitPoint.To<EditorDOMPointType>();
+    }
+    if (!mPreviousNode) {
+      return EditorDOMPointType(mNextNode);
+    }
+    return EditorDOMPointType::After(mPreviousNode);
+  }
+
+  SplitNodeResult() = delete;
+  SplitNodeResult(const SplitNodeResult&) = delete;
+  SplitNodeResult& operator=(const SplitNodeResult&) = delete;
+  SplitNodeResult(SplitNodeResult&&) = default;
+  SplitNodeResult& operator=(SplitNodeResult&&) = default;
+
+  /**
+   * This constructor should be used for setting specific caret point instead of
+   * aSplitResult's one.
+   */
+  SplitNodeResult(SplitNodeResult&& aSplitResult,
+                  const EditorDOMPoint& aNewCaretPoint)
+      : SplitNodeResult(std::move(aSplitResult)) {
+    SetCaretPoint(aNewCaretPoint);
+  }
+  SplitNodeResult(SplitNodeResult&& aSplitResult,
+                  EditorDOMPoint&& aNewCaretPoint)
+      : SplitNodeResult(std::move(aSplitResult)) {
+    SetCaretPoint(std::move(aNewCaretPoint));
+  }
+
+  /**
+   * This constructor shouldn't be used by anybody except methods which
+   * use this as result when it succeeds.
+   *
+   * @param aNewNode    The node which is newly created.
+   * @param aSplitNode  The node which was split.
+   * @param aDirection  The split direction which the HTML editor tried to split
+   *                    a node with.
+   * @param aNewCaretPoint
+   *                    An optional new caret position.  If this is omitted,
+   *                    the point between new node and split node will be
+   *                    suggested.
+   */
+  SplitNodeResult(nsIContent& aNewNode, nsIContent& aSplitNode,
+                  SplitNodeDirection aDirection,
+                  const Maybe<EditorDOMPoint>& aNewCaretPoint = Nothing())
+      : CaretPoint(aNewCaretPoint.isSome()
+                       ? aNewCaretPoint.ref()
+                       : EditorDOMPoint::AtEndOf(*PreviousNode(
+                             aDirection, &aNewNode, &aSplitNode))),
+        mPreviousNode(PreviousNode(aDirection, &aNewNode, &aSplitNode)),
+        mNextNode(NextNode(aDirection, &aNewNode, &aSplitNode)),
+        mDirection(aDirection) {}
+
+  SplitNodeResult ToHandledResult() const {
+    CaretPointHandled();
+    SplitNodeResult result(mDirection);
+    result.mPreviousNode = GetPreviousContent();
+    result.mNextNode = GetNextContent();
+    MOZ_DIAGNOSTIC_ASSERT(result.Handled());
+    // Don't recompute the caret position because in this case, split has not
+    // occurred yet.  In the case,  the caller shouldn't need to update
+    // selection.
+    result.SetCaretPoint(CaretPointRef());
+    return result;
+  }
+
+  /**
+   * The following factory methods creates a SplitNodeResult instance for the
+   * special cases.
+   *
+   * @param aDeeperSplitNodeResult
+   *                    If the splitter has already split a child or a
+   *                    descendant of the latest split node, the split node
+   *                    result should be specified.
+   */
+  static inline SplitNodeResult HandledButDidNotSplitDueToEndOfContainer(
+      nsIContent& aNotSplitNode, SplitNodeDirection aDirection,
+      const SplitNodeResult* aDeeperSplitNodeResult = nullptr) {
+    SplitNodeResult result(aDirection);
+    result.mPreviousNode = &aNotSplitNode;
+    // Caret should be put at the last split point instead of current node.
+    if (aDeeperSplitNodeResult) {
+      result.SetCaretPoint(aDeeperSplitNodeResult->CaretPointRef());
+      aDeeperSplitNodeResult->IgnoreCaretPointSuggestion();
+    }
+    return result;
+  }
+
+  static inline SplitNodeResult HandledButDidNotSplitDueToStartOfContainer(
+      nsIContent& aNotSplitNode, SplitNodeDirection aDirection,
+      const SplitNodeResult* aDeeperSplitNodeResult = nullptr) {
+    SplitNodeResult result(aDirection);
+    result.mNextNode = &aNotSplitNode;
+    // Caret should be put at the last split point instead of current node.
+    if (aDeeperSplitNodeResult) {
+      result.SetCaretPoint(aDeeperSplitNodeResult->CaretPointRef());
+      aDeeperSplitNodeResult->IgnoreCaretPointSuggestion();
+    }
+    return result;
+  }
+
+  template <typename PT, typename CT>
+  static inline SplitNodeResult NotHandled(
+      const EditorDOMPointBase<PT, CT>& aGivenSplitPoint,
+      SplitNodeDirection aDirection,
+      const SplitNodeResult* aDeeperSplitNodeResult = nullptr) {
+    SplitNodeResult result(aDirection);
+    result.mGivenSplitPoint = aGivenSplitPoint;
+    // Caret should be put at the last split point instead of current node.
+    if (aDeeperSplitNodeResult) {
+      result.SetCaretPoint(aDeeperSplitNodeResult->CaretPointRef());
+      aDeeperSplitNodeResult->IgnoreCaretPointSuggestion();
+    }
+    return result;
+  }
+
+  /**
+   * Returns aSplitNodeResult as-is unless it didn't split a node but
+   * aDeeperSplitNodeResult has already split a child or a descendant and has a
+   * valid point to put caret around there.  In the case, this return
+   * aSplitNodeResult which suggests a caret position around the last split
+   * point.
+   */
+  static inline SplitNodeResult MergeWithDeeperSplitNodeResult(
+      SplitNodeResult&& aSplitNodeResult,
+      const SplitNodeResult& aDeeperSplitNodeResult) {
+    aSplitNodeResult.UnmarkAsHandledCaretPoint();
+    aDeeperSplitNodeResult.IgnoreCaretPointSuggestion();
+    if (aSplitNodeResult.DidSplit() ||
+        !aDeeperSplitNodeResult.HasCaretPointSuggestion()) {
+      return std::move(aSplitNodeResult);
+    }
+    SplitNodeResult result(std::move(aSplitNodeResult));
+    result.SetCaretPoint(aDeeperSplitNodeResult.CaretPointRef());
+    return result;
+  }
+
+#ifdef DEBUG
+  ~SplitNodeResult() {
+    MOZ_ASSERT(!HasCaretPointSuggestion() || CaretPointHandled());
+  }
+#endif
+
+ private:
+  explicit SplitNodeResult(SplitNodeDirection aDirection)
+      : mDirection(aDirection) {}
+
+  // Helper methods to consider previous/next node from new/old node and split
+  // direction.
+  static nsIContent* PreviousNode(SplitNodeDirection aDirection,
+                                  nsIContent* aNewOne, nsIContent* aOldOne) {
+    return aDirection == SplitNodeDirection::LeftNodeIsNewOne ? aNewOne
+                                                              : aOldOne;
+  }
+  static nsIContent* NextNode(SplitNodeDirection aDirection,
+                              nsIContent* aNewOne, nsIContent* aOldOne) {
+    return aDirection == SplitNodeDirection::LeftNodeIsNewOne ? aOldOne
+                                                              : aNewOne;
+  }
+
+  // When methods which return this class split some nodes actually, they
+  // need to set a set of left node and right node to this class.  However,
+  // one or both of them may be moved or removed by mutation observer.
+  // In such case, we cannot represent the point with EditorDOMPoint since
+  // it requires current container node.  Therefore, we need to use
+  // nsCOMPtr<nsIContent> here instead.
+  nsCOMPtr<nsIContent> mPreviousNode;
+  nsCOMPtr<nsIContent> mNextNode;
+
+  // Methods which return this class may not split any nodes actually.  Then,
+  // they may want to return given split point as is since such behavior makes
+  // their callers simpler.  In this case, the point may be in a text node
+  // which cannot be represented as a node.  Therefore, we need EditorDOMPoint
+  // for representing the point.
+  EditorDOMPoint mGivenSplitPoint;
+
+  SplitNodeDirection mDirection;
+};
+
+/*****************************************************************************
+ * JoinNodesResult is a simple class for HTMLEditor::JoinNodesWithTransaction().
+ * This makes the callers' code easier to read.
+ *****************************************************************************/
+class MOZ_STACK_CLASS JoinNodesResult final {
+ public:
+  MOZ_KNOWN_LIVE nsIContent* ExistingContent() const {
+    return mJoinedPoint.ContainerAs<nsIContent>();
+  }
+  template <typename EditorDOMPointType>
+  EditorDOMPointType AtExistingContent() const {
+    return EditorDOMPointType(mJoinedPoint.ContainerAs<nsIContent>());
+  }
+
+  MOZ_KNOWN_LIVE nsIContent* RemovedContent() const { return mRemovedContent; }
+  template <typename EditorDOMPointType>
+  EditorDOMPointType AtRemovedContent() const {
+    if (mRemovedContent) {
+      return EditorDOMPointType(mRemovedContent);
+    }
+    return EditorDOMPointType();
+  }
+
+  template <typename EditorDOMPointType>
+  EditorDOMPointType AtJoinedPoint() const {
+    return mJoinedPoint.To<EditorDOMPointType>();
+  }
+
+  JoinNodesResult() = delete;
+
+  /**
+   * This constructor shouldn't be used by anybody except methods which
+   * use this as result when it succeeds.
+   *
+   * @param aJoinedPoint        First child of right node or first character.
+   * @param aRemovedContent     The node which was removed from the parent.
+   * @param aDirection          The join direction which the HTML editor tried
+   *                            to join the nodes with.
+   */
+  JoinNodesResult(const EditorDOMPoint& aJoinedPoint,
+                  nsIContent& aRemovedContent, JoinNodesDirection aDirection)
+      : mJoinedPoint(aJoinedPoint), mRemovedContent(&aRemovedContent) {
+    MOZ_DIAGNOSTIC_ASSERT(aJoinedPoint.IsInContentNode());
+  }
+
+  JoinNodesResult(const JoinNodesResult& aOther) = delete;
+  JoinNodesResult& operator=(const JoinNodesResult& aOther) = delete;
+  JoinNodesResult(JoinNodesResult&& aOther) = default;
+  JoinNodesResult& operator=(JoinNodesResult&& aOther) = default;
+
+ private:
+  EditorDOMPoint mJoinedPoint;
+  MOZ_KNOWN_LIVE nsCOMPtr<nsIContent> mRemovedContent;
+};
+
+/*****************************************************************************
+ * SplitRangeOffFromNodeResult class is a simple class for methods which split a
+ * node at 2 points for making part of the node split off from the node.
+ *****************************************************************************/
+class MOZ_STACK_CLASS SplitRangeOffFromNodeResult final : public CaretPoint {
+ public:
+  /**
+   * GetLeftContent() returns new created node before the part of quarried out.
+   * This may return nullptr if the method didn't split at start edge of
+   * the node.
+   */
+  MOZ_KNOWN_LIVE nsIContent* GetLeftContent() const { return mLeftContent; }
+  template <typename ContentNodeType>
+  MOZ_KNOWN_LIVE ContentNodeType* GetLeftContentAs() const {
+    return ContentNodeType::FromNodeOrNull(GetLeftContent());
+  }
+  constexpr nsCOMPtr<nsIContent>&& UnwrapLeftContent() {
+    mMovedContent = true;
+    return std::move(mLeftContent);
+  }
+
+  /**
+   * GetMiddleContent() returns new created node between left node and right
+   * node.  I.e., this is quarried out from the node.  This may return nullptr
+   * if the method unwrapped the middle node.
+   */
+  MOZ_KNOWN_LIVE nsIContent* GetMiddleContent() const { return mMiddleContent; }
+  template <typename ContentNodeType>
+  MOZ_KNOWN_LIVE ContentNodeType* GetMiddleContentAs() const {
+    return ContentNodeType::FromNodeOrNull(GetMiddleContent());
+  }
+  constexpr nsCOMPtr<nsIContent>&& UnwrapMiddleContent() {
+    mMovedContent = true;
+    return std::move(mMiddleContent);
+  }
+
+  /**
+   * GetRightContent() returns the right node after the part of quarried out.
+   * This may return nullptr it the method didn't split at end edge of the
+   * node.
+   */
+  MOZ_KNOWN_LIVE nsIContent* GetRightContent() const { return mRightContent; }
+  template <typename ContentNodeType>
+  MOZ_KNOWN_LIVE ContentNodeType* GetRightContentAs() const {
+    return ContentNodeType::FromNodeOrNull(GetRightContent());
+  }
+  constexpr nsCOMPtr<nsIContent>&& UnwrapRightContent() {
+    mMovedContent = true;
+    return std::move(mRightContent);
+  }
+
+  /**
+   * GetLeftmostContent() returns the leftmost content after trying to
+   * split twice.  If the node was not split, this returns the original node.
+   */
+  MOZ_KNOWN_LIVE nsIContent* GetLeftmostContent() const {
+    MOZ_ASSERT(!mMovedContent);
+    return mLeftContent ? mLeftContent
+                        : (mMiddleContent ? mMiddleContent : mRightContent);
+  }
+  template <typename ContentNodeType>
+  MOZ_KNOWN_LIVE ContentNodeType* GetLeftmostContentAs() const {
+    return ContentNodeType::FromNodeOrNull(GetLeftmostContent());
+  }
+
+  /**
+   * GetRightmostContent() returns the rightmost content after trying to
+   * split twice.  If the node was not split, this returns the original node.
+   */
+  MOZ_KNOWN_LIVE nsIContent* GetRightmostContent() const {
+    MOZ_ASSERT(!mMovedContent);
+    return mRightContent ? mRightContent
+                         : (mMiddleContent ? mMiddleContent : mLeftContent);
+  }
+  template <typename ContentNodeType>
+  MOZ_KNOWN_LIVE ContentNodeType* GetRightmostContentAs() const {
+    return ContentNodeType::FromNodeOrNull(GetRightmostContent());
+  }
+
+  [[nodiscard]] bool DidSplit() const { return mLeftContent || mRightContent; }
+
+  SplitRangeOffFromNodeResult() = delete;
+
+  SplitRangeOffFromNodeResult(nsIContent* aLeftContent,
+                              nsIContent* aMiddleContent,
+                              nsIContent* aRightContent)
+      : CaretPoint(),
+        mLeftContent(aLeftContent),
+        mMiddleContent(aMiddleContent),
+        mRightContent(aRightContent) {}
+
+  SplitRangeOffFromNodeResult(nsIContent* aLeftContent,
+                              nsIContent* aMiddleContent,
+                              nsIContent* aRightContent,
+                              EditorDOMPoint&& aPointToPutCaret)
+      : CaretPoint(std::move(aPointToPutCaret)),
+        mLeftContent(aLeftContent),
+        mMiddleContent(aMiddleContent),
+        mRightContent(aRightContent) {}
+
+  SplitRangeOffFromNodeResult(const SplitRangeOffFromNodeResult& aOther) =
+      delete;
+  SplitRangeOffFromNodeResult& operator=(
+      const SplitRangeOffFromNodeResult& aOther) = delete;
+  SplitRangeOffFromNodeResult(SplitRangeOffFromNodeResult&& aOther) noexcept
+      : CaretPoint(aOther.UnwrapCaretPoint()),
+        mLeftContent(std::move(aOther.mLeftContent)),
+        mMiddleContent(std::move(aOther.mMiddleContent)),
+        mRightContent(std::move(aOther.mRightContent)) {
+    MOZ_ASSERT(!aOther.mMovedContent);
+  }
+  SplitRangeOffFromNodeResult& operator=(SplitRangeOffFromNodeResult&& aOther) =
+      delete;  // due to bug 1792638
+
+#ifdef DEBUG
+  ~SplitRangeOffFromNodeResult() {
+    MOZ_ASSERT(!HasCaretPointSuggestion() || CaretPointHandled());
+  }
+#endif
+
+ private:
+  MOZ_KNOWN_LIVE nsCOMPtr<nsIContent> mLeftContent;
+  MOZ_KNOWN_LIVE nsCOMPtr<nsIContent> mMiddleContent;
+  MOZ_KNOWN_LIVE nsCOMPtr<nsIContent> mRightContent;
+
+  bool mutable mMovedContent = false;
+};
+
+/*****************************************************************************
+ * SplitRangeOffResult class is a simple class for methods which splits
+ * specific ancestor elements at 2 DOM points.
+ *****************************************************************************/
+class MOZ_STACK_CLASS SplitRangeOffResult final : public CaretPoint {
+ public:
+  constexpr bool Handled() const { return mHandled; }
+
+  /**
+   * The start boundary is at the right of split at split point.  The end
+   * boundary is at right node of split at end point, i.e., the end boundary
+   * points out of the range to have been split off.
+   */
+  constexpr const EditorDOMRange& RangeRef() const { return mRange; }
+
+  SplitRangeOffResult() = delete;
+
+  /**
+   * Constructor for success case.
+   *
+   * @param aTrackedRangeStart          The range whose start is at topmost
+   *                                    right node child at start point if
+   *                                    actually split there, or at the point
+   *                                    to be tried to split, and whose end is
+   *                                    at topmost right node child at end point
+   *                                    if actually split there, or at the point
+   *                                    to be tried to split.  Note that if the
+   *                                    method allows to run script after
+   *                                    splitting the range boundaries, they
+   *                                    should be tracked with
+   *                                    AutoTrackDOMRange.
+   * @param aSplitNodeResultAtStart     Raw split node result at start point.
+   * @param aSplitNodeResultAtEnd       Raw split node result at start point.
+   */
+  SplitRangeOffResult(EditorDOMRange&& aTrackedRange,
+                      SplitNodeResult&& aSplitNodeResultAtStart,
+                      SplitNodeResult&& aSplitNodeResultAtEnd)
+      : CaretPoint(),
+        mRange(std::move(aTrackedRange)),
+        mHandled(aSplitNodeResultAtStart.Handled() ||
+                 aSplitNodeResultAtEnd.Handled()) {
+    MOZ_ASSERT(mRange.StartRef().IsSet());
+    MOZ_ASSERT(mRange.EndRef().IsSet());
+    // The given results are created for creating this instance so that the
+    // caller may not need to handle with them.  For making who taking the
+    // responsible clearer, we should move them into this constructor.
+    EditorDOMPoint pointToPutCaret;
+    SplitNodeResult splitNodeResultAtStart(std::move(aSplitNodeResultAtStart));
+    SplitNodeResult splitNodeResultAtEnd(std::move(aSplitNodeResultAtEnd));
+    splitNodeResultAtStart.MoveCaretPointTo(
+        pointToPutCaret, {SuggestCaret::OnlyIfHasSuggestion});
+    splitNodeResultAtEnd.MoveCaretPointTo(pointToPutCaret,
+                                          {SuggestCaret::OnlyIfHasSuggestion});
+    SetCaretPoint(std::move(pointToPutCaret));
+  }
+
+  SplitRangeOffResult(const SplitRangeOffResult& aOther) = delete;
+  SplitRangeOffResult& operator=(const SplitRangeOffResult& aOther) = delete;
+  SplitRangeOffResult(SplitRangeOffResult&& aOther) = default;
+  SplitRangeOffResult& operator=(SplitRangeOffResult&& aOther) = default;
+
+ private:
+  EditorDOMRange mRange;
+
+  // If you need to store previous and/or next node at start/end point,
+  // you might be able to use `SplitNodeResult::GetPreviousNode()` etc in the
+  // constructor only when `SplitNodeResult::Handled()` returns true.  But
+  // the node might have gone with another DOM tree mutation.  So, be careful
+  // if you do it.
+
+  bool mHandled;
+};
+
+/******************************************************************************
+ * DOM tree iterators
+ *****************************************************************************/
+
+class MOZ_RAII DOMIterator {
+ public:
+  explicit DOMIterator();
+  explicit DOMIterator(nsINode& aNode);
+  virtual ~DOMIterator() = default;
+
+  nsresult Init(nsRange& aRange);
+  nsresult Init(const RawRangeBoundary& aStartRef,
+                const RawRangeBoundary& aEndRef);
+
+  template <class NodeClass>
+  void AppendAllNodesToArray(
+      nsTArray<OwningNonNull<NodeClass>>& aArrayOfNodes) const;
+
+  /**
+   * AppendNodesToArray() calls aFunctor before appending found node to
+   * aArrayOfNodes.  If aFunctor returns false, the node will be ignored.
+   * You can use aClosure instead of capturing something with lambda.
+   * Note that aNode is guaranteed that it's an instance of NodeClass
+   * or its sub-class.
+   * XXX If we can make type of aNode templated without std::function,
+   *     it'd be better, though.
+   */
+  using BoolFunctor = bool (*)(nsINode& aNode, void* aClosure);
+  template <class NodeClass>
+  void AppendNodesToArray(BoolFunctor aFunctor,
+                          nsTArray<OwningNonNull<NodeClass>>& aArrayOfNodes,
+                          void* aClosure = nullptr) const;
+
+ protected:
+  ContentIteratorBase* mIter;
+  PostContentIterator mPostOrderIter;
+};
+
+class MOZ_RAII DOMSubtreeIterator final : public DOMIterator {
+ public:
+  explicit DOMSubtreeIterator();
+  virtual ~DOMSubtreeIterator() = default;
+
+  nsresult Init(nsRange& aRange);
+
+ private:
+  ContentSubtreeIterator mSubtreeIter;
+  explicit DOMSubtreeIterator(nsINode& aNode) = delete;
+};
+
+/******************************************************************************
+ * ReplaceRangeData
+ *
+ * This represents range to be replaced and replacing string.
+ *****************************************************************************/
+
+template <typename EditorDOMPointType>
+class MOZ_STACK_CLASS ReplaceRangeDataBase final {
+ public:
+  ReplaceRangeDataBase() = default;
+  template <typename OtherEditorDOMRangeType>
+  ReplaceRangeDataBase(const OtherEditorDOMRangeType& aRange,
+                       const nsAString& aReplaceString)
+      : mRange(aRange), mReplaceString(aReplaceString) {}
+  template <typename StartPointType, typename EndPointType>
+  ReplaceRangeDataBase(const StartPointType& aStart, const EndPointType& aEnd,
+                       const nsAString& aReplaceString)
+      : mRange(aStart, aEnd), mReplaceString(aReplaceString) {}
+
+  bool IsSet() const { return mRange.IsPositioned(); }
+  bool IsSetAndValid() const { return mRange.IsPositionedAndValid(); }
+  bool Collapsed() const { return mRange.Collapsed(); }
+  bool HasReplaceString() const { return !mReplaceString.IsEmpty(); }
+  const EditorDOMPointType& StartRef() const { return mRange.StartRef(); }
+  const EditorDOMPointType& EndRef() const { return mRange.EndRef(); }
+  const EditorDOMRangeBase<EditorDOMPointType>& RangeRef() const {
+    return mRange;
+  }
+  const nsString& ReplaceStringRef() const { return mReplaceString; }
+
+  template <typename PointType>
+  MOZ_NEVER_INLINE_DEBUG void SetStart(const PointType& aStart) {
+    mRange.SetStart(aStart);
+  }
+  template <typename PointType>
+  MOZ_NEVER_INLINE_DEBUG void SetEnd(const PointType& aEnd) {
+    mRange.SetEnd(aEnd);
+  }
+  template <typename StartPointType, typename EndPointType>
+  MOZ_NEVER_INLINE_DEBUG void SetStartAndEnd(const StartPointType& aStart,
+                                             const EndPointType& aEnd) {
+    mRange.SetRange(aStart, aEnd);
+  }
+  template <typename OtherEditorDOMRangeType>
+  MOZ_NEVER_INLINE_DEBUG void SetRange(const OtherEditorDOMRangeType& aRange) {
+    mRange = aRange;
+  }
+  void SetReplaceString(const nsAString& aReplaceString) {
+    mReplaceString = aReplaceString;
+  }
+  template <typename StartPointType, typename EndPointType>
+  MOZ_NEVER_INLINE_DEBUG void SetStartAndEnd(const StartPointType& aStart,
+                                             const EndPointType& aEnd,
+                                             const nsAString& aReplaceString) {
+    SetStartAndEnd(aStart, aEnd);
+    SetReplaceString(aReplaceString);
+  }
+  template <typename OtherEditorDOMRangeType>
+  MOZ_NEVER_INLINE_DEBUG void Set(const OtherEditorDOMRangeType& aRange,
+                                  const nsAString& aReplaceString) {
+    SetRange(aRange);
+    SetReplaceString(aReplaceString);
+  }
+
+ private:
+  EditorDOMRangeBase<EditorDOMPointType> mRange;
+  // This string may be used with ReplaceTextTransaction.  Therefore, for
+  // avoiding memory copy, we should store it with nsString rather than
+  // nsAutoString.
+  nsString mReplaceString;
+};
+
+/******************************************************************************
+ * EditorElementStyle represents a generic style of element
+ ******************************************************************************/
+
+class MOZ_STACK_CLASS EditorElementStyle {
+ public:
+#define DEFINE_FACTORY(aName, aAttr)            \
+  constexpr static EditorElementStyle aName() { \
+    return EditorElementStyle(*(aAttr));        \
+  }
+
+  // text-align, caption-side, a pair of margin-left and margin-right
+  DEFINE_FACTORY(Align, nsGkAtoms::align)
+  // background-color
+  DEFINE_FACTORY(BGColor, nsGkAtoms::bgcolor)
+  // background-image
+  DEFINE_FACTORY(Background, nsGkAtoms::background)
+  // border
+  DEFINE_FACTORY(Border, nsGkAtoms::border)
+  // height
+  DEFINE_FACTORY(Height, nsGkAtoms::height)
+  // color
+  DEFINE_FACTORY(Text, nsGkAtoms::text)
+  // list-style-type
+  DEFINE_FACTORY(Type, nsGkAtoms::type)
+  // vertical-align
+  DEFINE_FACTORY(VAlign, nsGkAtoms::valign)
+  // width
+  DEFINE_FACTORY(Width, nsGkAtoms::width)
+
+  static EditorElementStyle Create(const nsAtom& aAttribute) {
+    MOZ_DIAGNOSTIC_ASSERT(IsHTMLStyle(&aAttribute));
+    return EditorElementStyle(*aAttribute.AsStatic());
+  }
+
+  [[nodiscard]] static bool IsHTMLStyle(const nsAtom* aAttribute) {
+    return aAttribute == nsGkAtoms::align || aAttribute == nsGkAtoms::bgcolor ||
+           aAttribute == nsGkAtoms::background ||
+           aAttribute == nsGkAtoms::border || aAttribute == nsGkAtoms::height ||
+           aAttribute == nsGkAtoms::text || aAttribute == nsGkAtoms::type ||
+           aAttribute == nsGkAtoms::valign || aAttribute == nsGkAtoms::width;
+  }
+
+  /**
+   * Returns true if the style can be represented by CSS and it's possible to
+   * apply the style with CSS.
+   */
+  [[nodiscard]] bool IsCSSSettable(const nsStaticAtom& aTagName) const;
+  [[nodiscard]] bool IsCSSSettable(const dom::Element& aElement) const;
+
+  /**
+   * Returns true if the style can be represented by CSS and it's possible to
+   * remove the style with CSS.
+   */
+  [[nodiscard]] bool IsCSSRemovable(const nsStaticAtom& aTagName) const;
+  [[nodiscard]] bool IsCSSRemovable(const dom::Element& aElement) const;
+
+  nsStaticAtom* Style() const { return mStyle; }
+
+  [[nodiscard]] bool IsInlineStyle() const { return !mStyle; }
+  inline EditorInlineStyle& AsInlineStyle();
+  inline const EditorInlineStyle& AsInlineStyle() const;
+
+ protected:
+  MOZ_KNOWN_LIVE nsStaticAtom* mStyle = nullptr;
+  EditorElementStyle() = default;
+
+ private:
+  constexpr explicit EditorElementStyle(const nsStaticAtom& aStyle)
+      // Needs const_cast hack here because the this class users may want
+      // non-const nsStaticAtom pointer due to bug 1794954
+      : mStyle(const_cast<nsStaticAtom*>(&aStyle)) {}
+};
+
+/******************************************************************************
+ * EditorInlineStyle represents an inline style.
+ ******************************************************************************/
+
+struct MOZ_STACK_CLASS EditorInlineStyle : public EditorElementStyle {
+  // nullptr if you want to remove all inline styles.
+  // Otherwise, one of the presentation tag names which we support in style
+  // editor, and there special cases: nsGkAtoms::href means <a href="...">,
+  // and nsGkAtoms::name means <a name="...">.
+  MOZ_KNOWN_LIVE nsStaticAtom* const mHTMLProperty = nullptr;
+  // For some mHTMLProperty values, need to be set to its attribute name.
+  // E.g., nsGkAtoms::size and nsGkAtoms::face for nsGkAtoms::font.
+  // Otherwise, nullptr.
+  // TODO: Once we stop using these structure to wrap selected content nodes
+  //       with <a href> elements, we can make this nsStaticAtom*.
+  MOZ_KNOWN_LIVE const RefPtr<nsAtom> mAttribute;
+
+  /**
+   * Returns true if the style means that all inline styles should be removed.
+   */
+  [[nodiscard]] bool IsStyleToClearAllInlineStyles() const {
+    return !mHTMLProperty;
+  }
+
+  /**
+   * Returns true if the style is about <a>.
+   */
+  [[nodiscard]] bool IsStyleOfAnchorElement() const {
+    return mHTMLProperty == nsGkAtoms::a || mHTMLProperty == nsGkAtoms::href ||
+           mHTMLProperty == nsGkAtoms::name;
+  }
+
+  /**
+   * Returns true if the style is invertible with CSS.
+   */
+  [[nodiscard]] bool IsInvertibleWithCSS() const {
+    return mHTMLProperty == nsGkAtoms::b;
+  }
+
+  /**
+   * Returns true if the style can be specified with text-decoration.
+   */
+  enum class IgnoreSElement { No, Yes };
+  [[nodiscard]] bool IsStyleOfTextDecoration(
+      IgnoreSElement aIgnoreSElement) const {
+    return mHTMLProperty == nsGkAtoms::u ||
+           mHTMLProperty == nsGkAtoms::strike ||
+           (aIgnoreSElement == IgnoreSElement::No &&
+            mHTMLProperty == nsGkAtoms::s);
+  }
+
+  /**
+   * Returns true if the style can be represented with <font>.
+   */
+  [[nodiscard]] bool IsStyleOfFontElement() const {
+    MOZ_ASSERT_IF(
+        mHTMLProperty == nsGkAtoms::font,
+        mAttribute == nsGkAtoms::bgcolor || mAttribute == nsGkAtoms::color ||
+            mAttribute == nsGkAtoms::face || mAttribute == nsGkAtoms::size);
+    return mHTMLProperty == nsGkAtoms::font && mAttribute != nsGkAtoms::bgcolor;
+  }
+
+  /**
+   * Returns true if the style is font-size or <font size="...">.
+   */
+  [[nodiscard]] bool IsStyleOfFontSize() const {
+    return mHTMLProperty == nsGkAtoms::font && mAttribute == nsGkAtoms::size;
+  }
+
+  /**
+   * Returns true if the style is conflict with vertical-align even though
+   * they are not mapped to vertical-align in the CSS mode.
+   */
+  [[nodiscard]] bool IsStyleConflictingWithVerticalAlign() const {
+    return mHTMLProperty == nsGkAtoms::sup || mHTMLProperty == nsGkAtoms::sub;
+  }
+
+  /**
+   * If the style has a similar element  which should be removed when applying
+   * the style, this retuns an element name.  Otherwise, returns nullptr.
+   */
+  [[nodiscard]] nsStaticAtom* GetSimilarElementNameAtom() const {
+    if (mHTMLProperty == nsGkAtoms::b) {
+      return nsGkAtoms::strong;
+    }
+    if (mHTMLProperty == nsGkAtoms::i) {
+      return nsGkAtoms::em;
+    }
+    if (mHTMLProperty == nsGkAtoms::strike) {
+      return nsGkAtoms::s;
+    }
+    return nullptr;
+  }
+
+  /**
+   * Returns true if aContent is an HTML element and represents the style.
+   */
+  [[nodiscard]] bool IsRepresentedBy(const nsIContent& aContent) const;
+
+  /**
+   * Returns true if aElement has style attribute and specifies this style.
+   *
+   * TODO: Make aElement be constant, but it needs to touch CSSEditUtils a lot.
+   */
+  [[nodiscard]] Result<bool, nsresult> IsSpecifiedBy(
+      const HTMLEditor& aHTMLEditor, dom::Element& aElement) const;
+
+  explicit EditorInlineStyle(const nsStaticAtom& aHTMLProperty,
+                             nsAtom* aAttribute = nullptr)
+      : EditorInlineStyle(aHTMLProperty, aAttribute, HasValue::No) {}
+  EditorInlineStyle(const nsStaticAtom& aHTMLProperty,
+                    RefPtr<nsAtom>&& aAttribute)
+      : EditorInlineStyle(aHTMLProperty, aAttribute, HasValue::No) {}
+
+  /**
+   * Returns the instance which means remove all inline styles.
+   */
+  static EditorInlineStyle RemoveAllStyles() { return EditorInlineStyle(); }
+
+  PendingStyleCache ToPendingStyleCache(nsAString&& aValue) const;
+
+  bool operator==(const EditorInlineStyle& aOther) const {
+    return mHTMLProperty == aOther.mHTMLProperty &&
+           mAttribute == aOther.mAttribute;
+  }
+
+  bool MaybeHasValue() const { return mMaybeHasValue; }
+  inline EditorInlineStyleAndValue& AsInlineStyleAndValue();
+  inline const EditorInlineStyleAndValue& AsInlineStyleAndValue() const;
+
+ protected:
+  const bool mMaybeHasValue = false;
+
+  enum class HasValue { No, Yes };
+  EditorInlineStyle(const nsStaticAtom& aHTMLProperty, nsAtom* aAttribute,
+                    HasValue aHasValue)
+      // Needs const_cast hack here because the struct users may want
+      // non-const nsStaticAtom pointer due to bug 1794954
+      : mHTMLProperty(const_cast<nsStaticAtom*>(&aHTMLProperty)),
+        mAttribute(aAttribute),
+        mMaybeHasValue(aHasValue == HasValue::Yes) {}
+  EditorInlineStyle(const nsStaticAtom& aHTMLProperty,
+                    RefPtr<nsAtom>&& aAttribute, HasValue aHasValue)
+      // Needs const_cast hack here because the struct users may want
+      // non-const nsStaticAtom pointer due to bug 1794954
+      : mHTMLProperty(const_cast<nsStaticAtom*>(&aHTMLProperty)),
+        mAttribute(std::move(aAttribute)),
+        mMaybeHasValue(aHasValue == HasValue::Yes) {}
+  EditorInlineStyle(const EditorInlineStyle& aStyle, HasValue aHasValue)
+      : mHTMLProperty(aStyle.mHTMLProperty),
+        mAttribute(aStyle.mAttribute),
+        mMaybeHasValue(aHasValue == HasValue::Yes) {}
+
+ private:
+  EditorInlineStyle() = default;
+
+  using EditorElementStyle::AsInlineStyle;
+  using EditorElementStyle::IsInlineStyle;
+  using EditorElementStyle::Style;
+};
+
+inline EditorInlineStyle& EditorElementStyle::AsInlineStyle() {
+  return reinterpret_cast<EditorInlineStyle&>(*this);
+}
+
+inline const EditorInlineStyle& EditorElementStyle::AsInlineStyle() const {
+  return reinterpret_cast<const EditorInlineStyle&>(*this);
+}
+
+/******************************************************************************
+ * EditorInlineStyleAndValue represents an inline style and stores its value.
+ ******************************************************************************/
+
+struct MOZ_STACK_CLASS EditorInlineStyleAndValue : public EditorInlineStyle {
+  // Stores the value of mAttribute.
+  nsString const mAttributeValue;
+
+  bool IsStyleToClearAllInlineStyles() const = delete;
+  EditorInlineStyleAndValue() = delete;
+
+  explicit EditorInlineStyleAndValue(nsStaticAtom& aHTMLProperty)
+      : EditorInlineStyle(aHTMLProperty, nullptr, HasValue::No) {}
+  EditorInlineStyleAndValue(nsStaticAtom& aHTMLProperty, nsAtom& aAttribute,
+                            const nsAString& aValue)
+      : EditorInlineStyle(aHTMLProperty, &aAttribute, HasValue::Yes),
+        mAttributeValue(aValue) {}
+  EditorInlineStyleAndValue(nsStaticAtom& aHTMLProperty,
+                            RefPtr<nsAtom>&& aAttribute,
+                            const nsAString& aValue)
+      : EditorInlineStyle(aHTMLProperty, std::move(aAttribute), HasValue::Yes),
+        mAttributeValue(aValue) {
+    MOZ_ASSERT(mAttribute);
+  }
+  EditorInlineStyleAndValue(nsStaticAtom& aHTMLProperty, nsAtom& aAttribute,
+                            nsString&& aValue)
+      : EditorInlineStyle(aHTMLProperty, &aAttribute, HasValue::Yes),
+        mAttributeValue(std::move(aValue)) {}
+  EditorInlineStyleAndValue(nsStaticAtom& aHTMLProperty,
+                            RefPtr<nsAtom>&& aAttribute, nsString&& aValue)
+      : EditorInlineStyle(aHTMLProperty, std::move(aAttribute), HasValue::Yes),
+        mAttributeValue(aValue) {}
+
+  [[nodiscard]] static EditorInlineStyleAndValue ToInvert(
+      const EditorInlineStyle& aStyle) {
+    MOZ_ASSERT(aStyle.IsInvertibleWithCSS());
+    return EditorInlineStyleAndValue(aStyle, u"-moz-editor-invert-value"_ns);
+  }
+
+  // mHTMLProperty is never nullptr since all constructors guarantee it.
+  // Therefore, hide it and expose its reference instead.
+  MOZ_KNOWN_LIVE nsStaticAtom& HTMLPropertyRef() const {
+    MOZ_DIAGNOSTIC_ASSERT(mHTMLProperty);
+    return *mHTMLProperty;
+  }
+
+  [[nodiscard]] bool IsStyleToInvert() const {
+    return mAttributeValue.EqualsLiteral(u"-moz-editor-invert-value");
+  }
+
+  /**
+   * Returns true if this style is representable with HTML.
+   */
+  [[nodiscard]] bool IsRepresentableWithHTML() const {
+    // Use background-color in any elements
+    if (mAttribute == nsGkAtoms::bgcolor) {
+      return false;
+    }
+    // Inverting the style means that it's invertible with CSS
+    if (IsStyleToInvert()) {
+      return false;
+    }
+    return true;
+  }
+
+ private:
+  using EditorInlineStyle::mHTMLProperty;
+
+  EditorInlineStyleAndValue(const EditorInlineStyle& aStyle,
+                            const nsAString& aValue)
+      : EditorInlineStyle(aStyle, HasValue::Yes), mAttributeValue(aValue) {}
+
+  using EditorInlineStyle::AsInlineStyleAndValue;
+  using EditorInlineStyle::HasValue;
+};
+
+inline EditorInlineStyleAndValue& EditorInlineStyle::AsInlineStyleAndValue() {
+  return reinterpret_cast<EditorInlineStyleAndValue&>(*this);
+}
+
+inline const EditorInlineStyleAndValue&
+EditorInlineStyle::AsInlineStyleAndValue() const {
+  return reinterpret_cast<const EditorInlineStyleAndValue&>(*this);
+}
+
+}  // namespace mozilla
+
+#endif  // #ifndef HTMLEditHelpers_h