1 files changed, 443 insertions, 0 deletions
diff --git a/editor/libeditor/EditorUtils.h b/editor/libeditor/EditorUtils.h
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+/* -*- 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 mozilla_EditorUtils_h
+#define mozilla_EditorUtils_h
+
+#include "mozilla/EditorBase.h"      // for EditorBase
+#include "mozilla/EditorDOMPoint.h"  // for EditorDOMPoint, EditorDOMRange, etc
+#include "mozilla/EditorForwards.h"
+#include "mozilla/IntegerRange.h"       // for IntegerRange
+#include "mozilla/Maybe.h"              // for Maybe
+#include "mozilla/Result.h"             // for Result<>
+#include "mozilla/dom/Element.h"        // for dom::Element
+#include "mozilla/dom/HTMLBRElement.h"  // for dom::HTMLBRElement
+#include "mozilla/dom/Selection.h"      // for dom::Selection
+#include "mozilla/dom/Text.h"           // for dom::Text
+
+#include "nsAtom.h"          // for nsStaticAtom
+#include "nsCOMPtr.h"        // for nsCOMPtr
+#include "nsContentUtils.h"  // for nsContentUtils
+#include "nsDebug.h"         // for NS_WARNING, etc
+#include "nsError.h"         // for NS_SUCCESS_* and NS_ERROR_*
+#include "nsRange.h"         // for nsRange
+#include "nsString.h"        // for nsAString, nsString, etc
+
+class nsITransferable;
+
+namespace mozilla {
+
+enum class StyleWhiteSpace : uint8_t;
+
+enum class SuggestCaret {
+  // If specified, the method returns NS_OK when there is no recommended caret
+  // position.
+  OnlyIfHasSuggestion,
+  // If specified and if EditorBase::AllowsTransactionsToChangeSelection
+  // returns false, the method does nothing and returns NS_OK.
+  OnlyIfTransactionsAllowedToDoIt,
+  // If specified, the method returns
+  // NS_SUCCESS_EDITOR_BUT_IGNORED_TRIVIAL_ERROR even if
+  // EditorBase::CollapseSelectionTo returns an error except when
+  // NS_ERROR_EDITOR_DESTROYED.
+  AndIgnoreTrivialError,
+};
+
+/******************************************************************************
+ * CaretPoint is a wrapper of EditorDOMPoint and provides a helper method to
+ * collapse Selection there, or move it to a local variable.  This is typically
+ * used as the ok type of Result or a base class of DoSomethingResult classes.
+ ******************************************************************************/
+class MOZ_STACK_CLASS CaretPoint {
+ public:
+  explicit CaretPoint(const EditorDOMPoint& aPointToPutCaret)
+      : mCaretPoint(aPointToPutCaret) {}
+  explicit CaretPoint(EditorDOMPoint&& aPointToPutCaret)
+      : mCaretPoint(std::move(aPointToPutCaret)) {}
+
+  CaretPoint(const CaretPoint&) = delete;
+  CaretPoint& operator=(const CaretPoint&) = delete;
+  CaretPoint(CaretPoint&&) = default;
+  CaretPoint& operator=(CaretPoint&&) = default;
+
+  /**
+   * Suggest caret position to aEditorBase.
+   */
+  [[nodiscard]] MOZ_CAN_RUN_SCRIPT nsresult SuggestCaretPointTo(
+      const EditorBase& aEditorBase, const SuggestCaretOptions& aOptions) const;
+
+  /**
+   * IgnoreCaretPointSuggestion() should be called if the method does not want
+   * to use caret position recommended by this instance.
+   */
+  void IgnoreCaretPointSuggestion() const { mHandledCaretPoint = true; }
+
+  /**
+   * When propagating the result, it may not want to the caller modify
+   * selection.  In such case, this can clear the caret point.  Use
+   * IgnoreCaretPointSuggestion() in the caller side instead.
+   */
+  void ForgetCaretPointSuggestion() { mCaretPoint.Clear(); }
+
+  bool HasCaretPointSuggestion() const { return mCaretPoint.IsSet(); }
+  constexpr const EditorDOMPoint& CaretPointRef() const { return mCaretPoint; }
+  constexpr EditorDOMPoint&& UnwrapCaretPoint() {
+    mHandledCaretPoint = true;
+    return std::move(mCaretPoint);
+  }
+  bool CopyCaretPointTo(EditorDOMPoint& aPointToPutCaret,
+                        const SuggestCaretOptions& aOptions) const {
+    MOZ_ASSERT(!aOptions.contains(SuggestCaret::AndIgnoreTrivialError));
+    MOZ_ASSERT(
+        !aOptions.contains(SuggestCaret::OnlyIfTransactionsAllowedToDoIt));
+    if (aOptions.contains(SuggestCaret::OnlyIfHasSuggestion) &&
+        !mCaretPoint.IsSet()) {
+      return false;
+    }
+    aPointToPutCaret = mCaretPoint;
+    return true;
+  }
+  bool MoveCaretPointTo(EditorDOMPoint& aPointToPutCaret,
+                        const SuggestCaretOptions& aOptions) {
+    MOZ_ASSERT(!aOptions.contains(SuggestCaret::AndIgnoreTrivialError));
+    MOZ_ASSERT(
+        !aOptions.contains(SuggestCaret::OnlyIfTransactionsAllowedToDoIt));
+    if (aOptions.contains(SuggestCaret::OnlyIfHasSuggestion) &&
+        !mCaretPoint.IsSet()) {
+      return false;
+    }
+    aPointToPutCaret = UnwrapCaretPoint();
+    return true;
+  }
+  bool CopyCaretPointTo(EditorDOMPoint& aPointToPutCaret,
+                        const EditorBase& aEditorBase,
+                        const SuggestCaretOptions& aOptions) const;
+  bool MoveCaretPointTo(EditorDOMPoint& aPointToPutCaret,
+                        const EditorBase& aEditorBase,
+                        const SuggestCaretOptions& aOptions);
+
+ protected:
+  constexpr bool CaretPointHandled() const { return mHandledCaretPoint; }
+
+  void SetCaretPoint(const EditorDOMPoint& aCaretPoint) {
+    mHandledCaretPoint = false;
+    mCaretPoint = aCaretPoint;
+  }
+  void SetCaretPoint(EditorDOMPoint&& aCaretPoint) {
+    mHandledCaretPoint = false;
+    mCaretPoint = std::move(aCaretPoint);
+  }
+
+  void UnmarkAsHandledCaretPoint() { mHandledCaretPoint = true; }
+
+  CaretPoint() = default;
+
+ private:
+  EditorDOMPoint mCaretPoint;
+  bool mutable mHandledCaretPoint = false;
+};
+
+/***************************************************************************
+ * EditActionResult is useful to return the handling state of edit sub actions
+ * without out params.
+ */
+class MOZ_STACK_CLASS EditActionResult final {
+ public:
+  bool Canceled() const { return mCanceled; }
+  bool Handled() const { return mHandled; }
+  bool Ignored() const { return !mCanceled && !mHandled; }
+
+  void MarkAsCanceled() { mCanceled = true; }
+  void MarkAsHandled() { mHandled = true; }
+
+  EditActionResult& operator|=(const EditActionResult& aOther) {
+    mCanceled |= aOther.mCanceled;
+    mHandled |= aOther.mHandled;
+    return *this;
+  }
+
+  EditActionResult& operator|=(const MoveNodeResult& aMoveNodeResult);
+
+  static EditActionResult IgnoredResult() {
+    return EditActionResult(false, false);
+  }
+  static EditActionResult HandledResult() {
+    return EditActionResult(false, true);
+  }
+  static EditActionResult CanceledResult() {
+    return EditActionResult(true, true);
+  }
+
+  EditActionResult(const EditActionResult&) = delete;
+  EditActionResult& operator=(const EditActionResult&) = delete;
+  EditActionResult(EditActionResult&&) = default;
+  EditActionResult& operator=(EditActionResult&&) = default;
+
+ private:
+  bool mCanceled = false;
+  bool mHandled = false;
+
+  EditActionResult(bool aCanceled, bool aHandled)
+      : mCanceled(aCanceled), mHandled(aHandled) {}
+
+  EditActionResult() : mCanceled(false), mHandled(false) {}
+};
+
+/***************************************************************************
+ * CreateNodeResultBase is a simple class for CreateSomething() methods
+ * which want to return new node.
+ */
+template <typename NodeType>
+class MOZ_STACK_CLASS CreateNodeResultBase final : public CaretPoint {
+  using SelfType = CreateNodeResultBase<NodeType>;
+
+ public:
+  bool Handled() const { return mNode; }
+  NodeType* GetNewNode() const { return mNode; }
+  RefPtr<NodeType> UnwrapNewNode() { return std::move(mNode); }
+
+  CreateNodeResultBase() = delete;
+  explicit CreateNodeResultBase(NodeType& aNode) : mNode(&aNode) {}
+  explicit CreateNodeResultBase(NodeType& aNode,
+                                const EditorDOMPoint& aCandidateCaretPoint)
+      : CaretPoint(aCandidateCaretPoint), mNode(&aNode) {}
+  explicit CreateNodeResultBase(NodeType& aNode,
+                                EditorDOMPoint&& aCandidateCaretPoint)
+      : CaretPoint(std::move(aCandidateCaretPoint)), mNode(&aNode) {}
+
+  explicit CreateNodeResultBase(RefPtr<NodeType>&& aNode)
+      : mNode(std::move(aNode)) {}
+  explicit CreateNodeResultBase(RefPtr<NodeType>&& aNode,
+                                const EditorDOMPoint& aCandidateCaretPoint)
+      : CaretPoint(aCandidateCaretPoint), mNode(std::move(aNode)) {
+    MOZ_ASSERT(mNode);
+  }
+  explicit CreateNodeResultBase(RefPtr<NodeType>&& aNode,
+                                EditorDOMPoint&& aCandidateCaretPoint)
+      : CaretPoint(std::move(aCandidateCaretPoint)), mNode(std::move(aNode)) {
+    MOZ_ASSERT(mNode);
+  }
+
+  [[nodiscard]] static SelfType NotHandled() {
+    return SelfType(EditorDOMPoint());
+  }
+  [[nodiscard]] static SelfType NotHandled(
+      const EditorDOMPoint& aPointToPutCaret) {
+    SelfType result(aPointToPutCaret);
+    return result;
+  }
+  [[nodiscard]] static SelfType NotHandled(EditorDOMPoint&& aPointToPutCaret) {
+    SelfType result(std::move(aPointToPutCaret));
+    return result;
+  }
+
+#ifdef DEBUG
+  ~CreateNodeResultBase() {
+    MOZ_ASSERT(!HasCaretPointSuggestion() || CaretPointHandled());
+  }
+#endif
+
+  CreateNodeResultBase(const SelfType& aOther) = delete;
+  SelfType& operator=(const SelfType& aOther) = delete;
+  CreateNodeResultBase(SelfType&& aOther) = default;
+  SelfType& operator=(SelfType&& aOther) = default;
+
+ private:
+  explicit CreateNodeResultBase(const EditorDOMPoint& aCandidateCaretPoint)
+      : CaretPoint(aCandidateCaretPoint) {}
+  explicit CreateNodeResultBase(EditorDOMPoint&& aCandidateCaretPoint)
+      : CaretPoint(std::move(aCandidateCaretPoint)) {}
+
+  RefPtr<NodeType> mNode;
+};
+
+/***************************************************************************
+ * stack based helper class for calling EditorBase::EndTransaction() after
+ * EditorBase::BeginTransaction().  This shouldn't be used in editor classes
+ * or helper classes while an edit action is being handled.  Use
+ * AutoTransactionBatch in such cases since it uses non-virtual internal
+ * methods.
+ ***************************************************************************/
+class MOZ_RAII AutoTransactionBatchExternal final {
+ public:
+  MOZ_CAN_RUN_SCRIPT explicit AutoTransactionBatchExternal(
+      EditorBase& aEditorBase)
+      : mEditorBase(aEditorBase) {
+    MOZ_KnownLive(mEditorBase).BeginTransaction();
+  }
+
+  MOZ_CAN_RUN_SCRIPT ~AutoTransactionBatchExternal() {
+    MOZ_KnownLive(mEditorBase).EndTransaction();
+  }
+
+ private:
+  EditorBase& mEditorBase;
+};
+
+/******************************************************************************
+ * AutoSelectionRangeArray stores all ranges in `aSelection`.
+ * Note that modifying the ranges means modifing the selection ranges.
+ *****************************************************************************/
+class MOZ_STACK_CLASS AutoSelectionRangeArray final {
+ public:
+  explicit AutoSelectionRangeArray(dom::Selection& aSelection) {
+    for (const uint32_t i : IntegerRange(aSelection.RangeCount())) {
+      MOZ_ASSERT(aSelection.GetRangeAt(i));
+      mRanges.AppendElement(*aSelection.GetRangeAt(i));
+    }
+  }
+
+  AutoTArray<mozilla::OwningNonNull<nsRange>, 8> mRanges;
+};
+
+class EditorUtils final {
+ public:
+  using EditorType = EditorBase::EditorType;
+  using Selection = dom::Selection;
+
+  /**
+   * IsDescendantOf() checks if aNode is a child or a descendant of aParent.
+   * aOutPoint is set to the child of aParent.
+   *
+   * @return            true if aNode is a child or a descendant of aParent.
+   */
+  static bool IsDescendantOf(const nsINode& aNode, const nsINode& aParent,
+                             EditorRawDOMPoint* aOutPoint = nullptr);
+  static bool IsDescendantOf(const nsINode& aNode, const nsINode& aParent,
+                             EditorDOMPoint* aOutPoint);
+
+  /**
+   * Returns true if aContent is a <br> element and it's marked as padding for
+   * empty editor.
+   */
+  static bool IsPaddingBRElementForEmptyEditor(const nsIContent& aContent) {
+    const dom::HTMLBRElement* brElement =
+        dom::HTMLBRElement::FromNode(&aContent);
+    return brElement && brElement->IsPaddingForEmptyEditor();
+  }
+
+  /**
+   * Returns true if aContent is a <br> element and it's marked as padding for
+   * empty last line.
+   */
+  static bool IsPaddingBRElementForEmptyLastLine(const nsIContent& aContent) {
+    const dom::HTMLBRElement* brElement =
+        dom::HTMLBRElement::FromNode(&aContent);
+    return brElement && brElement->IsPaddingForEmptyLastLine();
+  }
+
+  /**
+   * IsEditableContent() returns true if aContent's data or children is ediable
+   * for the given editor type.  Be aware, returning true does NOT mean the
+   * node can be removed from its parent node, and returning false does NOT
+   * mean the node cannot be removed from the parent node.
+   * XXX May be the anonymous nodes in TextEditor not editable?  If it's not
+   *     so, we can get rid of aEditorType.
+   */
+  static bool IsEditableContent(const nsIContent& aContent,
+                                EditorType aEditorType) {
+    if (aEditorType == EditorType::HTML &&
+        (!aContent.IsEditable() || !aContent.IsInComposedDoc())) {
+      // FIXME(emilio): Why only for HTML editors? All content from the root
+      // content in text editors is also editable, so afaict we can remove the
+      // special-case.
+      return false;
+    }
+    return IsElementOrText(aContent);
+  }
+
+  /**
+   * Returns true if aContent is a usual element node (not padding <br> element
+   * for empty editor) or a text node.  In other words, returns true if
+   * aContent is a usual element node or visible data node.
+   */
+  static bool IsElementOrText(const nsIContent& aContent) {
+    if (aContent.IsText()) {
+      return true;
+    }
+    return aContent.IsElement() && !IsPaddingBRElementForEmptyEditor(aContent);
+  }
+
+  /**
+   * Get computed white-space style of aContent.
+   */
+  static Maybe<StyleWhiteSpace> GetComputedWhiteSpaceStyle(
+      const nsIContent& aContent);
+
+  /**
+   * IsWhiteSpacePreformatted() checks the style info for the node for the
+   * preformatted text style.  This does NOT flush layout.
+   */
+  static bool IsWhiteSpacePreformatted(const nsIContent& aContent);
+
+  /**
+   * IsNewLinePreformatted() checks whether the linefeed characters are
+   * preformatted or collapsible white-spaces.  This does NOT flush layout.
+   */
+  static bool IsNewLinePreformatted(const nsIContent& aContent);
+
+  /**
+   * IsOnlyNewLinePreformatted() checks whether the linefeed characters are
+   * preformated but white-spaces are collapsed, or otherwise.  I.e., this
+   * returns true only when `white-space:pre-line`.
+   */
+  static bool IsOnlyNewLinePreformatted(const nsIContent& aContent);
+
+  static nsStaticAtom* GetTagNameAtom(const nsAString& aTagName) {
+    if (aTagName.IsEmpty()) {
+      return nullptr;
+    }
+    nsAutoString lowerTagName;
+    nsContentUtils::ASCIIToLower(aTagName, lowerTagName);
+    return NS_GetStaticAtom(lowerTagName);
+  }
+
+  static nsStaticAtom* GetAttributeAtom(const nsAString& aAttribute) {
+    if (aAttribute.IsEmpty()) {
+      return nullptr;  // Don't use nsGkAtoms::_empty for attribute.
+    }
+    return NS_GetStaticAtom(aAttribute);
+  }
+
+  /**
+   * Helper method for deletion.  When this returns true, Selection will be
+   * computed with nsFrameSelection that also requires flushed layout
+   * information.
+   */
+  template <typename SelectionOrAutoRangeArray>
+  static bool IsFrameSelectionRequiredToExtendSelection(
+      nsIEditor::EDirection aDirectionAndAmount,
+      SelectionOrAutoRangeArray& aSelectionOrAutoRangeArray) {
+    switch (aDirectionAndAmount) {
+      case nsIEditor::eNextWord:
+      case nsIEditor::ePreviousWord:
+      case nsIEditor::eToBeginningOfLine:
+      case nsIEditor::eToEndOfLine:
+        return true;
+      case nsIEditor::ePrevious:
+      case nsIEditor::eNext:
+        return aSelectionOrAutoRangeArray.IsCollapsed();
+      default:
+        return false;
+    }
+  }
+
+  /**
+   * Returns true if aSelection includes the point in aParentContent.
+   */
+  static bool IsPointInSelection(const Selection& aSelection,
+                                 const nsINode& aParentNode, uint32_t aOffset);
+
+  /**
+   * Create an nsITransferable instance which has kUnicodeMime and
+   * kMozTextInternal flavors.
+   */
+  static Result<nsCOMPtr<nsITransferable>, nsresult>
+  CreateTransferableForPlainText(const dom::Document& aDocument);
+};
+
+}  // namespace mozilla
+
+#endif  // #ifndef mozilla_EditorUtils_h