Quelle EditorBase.cpp Sprache: C

/* -*- 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/. */

#include "EditorBase.h"

#include <stdio.h>   // for nullptr, stdout
#include <string.h>  // for strcmp

#include "AutoClonedRangeArray.h"  // for AutoClonedRangeArray and AutoClonedSelectionRangeArray
#include "AutoSelectionRestorer.h"
#include "ChangeAttributeTransaction.h"
#include "CompositionTransaction.h"
#include "DeleteContentTransactionBase.h"
#include "DeleteMultipleRangesTransaction.h"
#include "DeleteNodeTransaction.h"
#include "DeleteRangeTransaction.h"
#include "DeleteTextTransaction.h"
#include "EditAction.h"      // for EditSubAction
#include "EditorDOMPoint.h"  // for EditorDOMPoint
#include "EditorForwards.h"
#include "EditorUtils.h"          // for various helper classes.
#include "EditTransactionBase.h"  // for EditTransactionBase
#include "EditorEventListener.h"  // for EditorEventListener
#include "HTMLEditor.h"           // for HTMLEditor
#include "HTMLEditorInlines.h"
#include "HTMLEditUtils.h"           // for HTMLEditUtils
#include "InsertNodeTransaction.h"   // for InsertNodeTransaction
#include "InsertTextTransaction.h"   // for InsertTextTransaction
#include "JoinNodesTransaction.h"    // for JoinNodesTransaction
#include "PlaceholderTransaction.h"  // for PlaceholderTransaction
#include "SplitNodeTransaction.h"    // for SplitNodeTransaction
#include "TextEditor.h"              // for TextEditor

#include "ErrorList.h"
#include "gfxFontUtils.h"  // for gfxFontUtils
#include "mozilla/Assertions.h"
#include "mozilla/AsyncEventDispatcher.h"
#include "mozilla/EditorDOMPoint.h"
#include "mozilla/intl/BidiEmbeddingLevel.h"
#include "mozilla/BasePrincipal.h"            // for BasePrincipal
#include "mozilla/CheckedInt.h"               // for CheckedInt
#include "mozilla/ComposerCommandsUpdater.h"  // for ComposerCommandsUpdater
#include "mozilla/ContentEvents.h"            // for InternalClipboardEvent
#include "mozilla/DebugOnly.h"                // for DebugOnly
#include "mozilla/EditorSpellCheck.h"         // for EditorSpellCheck
#include "mozilla/Encoding.h"  // for Encoding (used in Document::GetDocumentCharacterSet)
#include "mozilla/EventDispatcher.h"     // for EventChainPreVisitor, etc.
#include "mozilla/FlushType.h"           // for FlushType::Frames
#include "mozilla/IMEContentObserver.h"  // for IMEContentObserver
#include "mozilla/IMEStateManager.h"     // for IMEStateManager
#include "mozilla/InputEventOptions.h"   // for InputEventOptions
#include "mozilla/IntegerRange.h"        // for IntegerRange
#include "mozilla/InternalMutationEvent.h"  // for NS_EVENT_BITS_MUTATION_CHARACTERDATAMODIFIED
#include "mozilla/mozalloc.h"               // for operator new, etc.
#include "mozilla/mozInlineSpellChecker.h"  // for mozInlineSpellChecker
#include "mozilla/mozSpellChecker.h"        // for mozSpellChecker
#include "mozilla/Preferences.h"            // for Preferences
#include "mozilla/PresShell.h"              // for PresShell
#include "mozilla/RangeBoundary.h"       // for RawRangeBoundary, RangeBoundary
#include "mozilla/ScopeExit.h"           // for MakeScopeExit
#include "mozilla/Services.h"            // for GetObserverService
#include "mozilla/StaticPrefs_bidi.h"    // for StaticPrefs::bidi_*
#include "mozilla/StaticPrefs_dom.h"     // for StaticPrefs::dom_*
#include "mozilla/StaticPrefs_editor.h"  // for StaticPrefs::editor_*
#include "mozilla/StaticPrefs_layout.h"  // for StaticPrefs::layout_*
#include "mozilla/TextComposition.h"     // for TextComposition
#include "mozilla/TextControlElement.h"  // for TextControlElement
#include "mozilla/TextInputListener.h"   // for TextInputListener
#include "mozilla/TextServicesDocument.h"  // for TextServicesDocument
#include "mozilla/TextEvents.h"
#include "mozilla/TransactionManager.h"    // for TransactionManager
#include "mozilla/dom/AbstractRange.h"     // for AbstractRange
#include "mozilla/dom/Attr.h"              // for Attr
#include "mozilla/dom/BorrowedAttrInfo.h"  // for BorrowedAttrInfo
#include "mozilla/dom/BrowsingContext.h"   // for BrowsingContext
#include "mozilla/dom/CharacterData.h"     // for CharacterData
#include "mozilla/dom/ContentParent.h"     // for ContentParent
#include "mozilla/dom/DataTransfer.h"      // for DataTransfer
#include "mozilla/dom/Document.h"          // for Document
#include "mozilla/dom/DocumentInlines.h"   // for GetObservingPresShell
#include "mozilla/dom/DragEvent.h"         // for DragEvent
#include "mozilla/dom/Element.h"           // for Element, nsINode::AsElement
#include "mozilla/dom/EventTarget.h"       // for EventTarget
#include "mozilla/dom/HTMLBodyElement.h"
#include "mozilla/dom/HTMLBRElement.h"
#include "mozilla/dom/Selection.h"    // for Selection, etc.
#include "mozilla/dom/StaticRange.h"  // for StaticRange
#include "mozilla/dom/Text.h"
#include "mozilla/dom/Event.h"
#include "nsAString.h"                // for nsAString::Length, etc.
#include "nsCCUncollectableMarker.h"  // for nsCCUncollectableMarker
#include "nsCaret.h"                  // for nsCaret
#include "nsCaseTreatment.h"
#include "nsCharTraits.h"              // for NS_IS_HIGH_SURROGATE, etc.
#include "nsContentUtils.h"            // for nsContentUtils
#include "nsCopySupport.h"             // for nsCopySupport
#include "nsDOMString.h"               // for DOMStringIsNull
#include "nsDebug.h"                   // for NS_WARNING, etc.
#include "nsError.h"                   // for NS_OK, etc.
#include "nsFocusManager.h"            // for nsFocusManager
#include "nsFrameSelection.h"          // for nsFrameSelection
#include "nsGenericHTMLElement.h"      // for nsGenericHTMLElement
#include "nsGkAtoms.h"                 // for nsGkAtoms, nsGkAtoms::dir
#include "nsIClipboard.h"              // for nsIClipboard
#include "nsIContent.h"                // for nsIContent
#include "nsIContentInlines.h"         // for nsINode::IsInDesignMode()
#include "nsIDocumentEncoder.h"        // for nsIDocumentEncoder
#include "nsIDocumentStateListener.h"  // for nsIDocumentStateListener
#include "nsIDocShell.h"               // for nsIDocShell
#include "nsIEditActionListener.h"     // for nsIEditActionListener
#include "nsIFrame.h"                  // for nsIFrame
#include "nsIInlineSpellChecker.h"     // for nsIInlineSpellChecker, etc.
#include "nsNameSpaceManager.h"        // for kNameSpaceID_None, etc.
#include "nsINode.h"                   // for nsINode, etc.
#include "nsISelectionController.h"    // for nsISelectionController, etc.
#include "nsISelectionDisplay.h"       // for nsISelectionDisplay, etc.
#include "nsISupports.h"               // for nsISupports
#include "nsISupportsUtils.h"          // for NS_ADDREF, NS_IF_ADDREF
#include "nsITransferable.h"           // for nsITransferable
#include "nsIWeakReference.h"          // for nsISupportsWeakReference
#include "nsIWidget.h"                 // for nsIWidget, IMEState, etc.
#include "nsPIDOMWindow.h"             // for nsPIDOMWindow
#include "nsPresContext.h"             // for nsPresContext
#include "nsRange.h"                   // for nsRange
#include "nsReadableUtils.h"           // for EmptyString, ToNewCString
#include "nsString.h"                  // for nsAutoString, nsString, etc.
#include "nsStringFwd.h"               // for nsString
#include "nsStyleConsts.h"             // for StyleDirection::Rtl, etc.
#include "nsStyleStruct.h"             // for nsStyleDisplay, nsStyleText, etc.
#include "nsStyleStructFwd.h"          // for nsIFrame::StyleUIReset, etc.
#include "nsTextNode.h"                // for nsTextNode
#include "nsThreadUtils.h"             // for nsRunnable
#include "prtime.h"                    // for PR_Now

class nsIOutputStream;
class nsITransferable;

namespace mozilla {

using namespace dom;
using namespace widget;

using EmptyCheckOption = HTMLEditUtils::EmptyCheckOption;
using LeafNodeType = HTMLEditUtils::LeafNodeType;
using LeafNodeTypes = HTMLEditUtils::LeafNodeTypes;
using WalkTreeOption = HTMLEditUtils::WalkTreeOption;

/*****************************************************************************
* mozilla::EditorBase
*****************************************************************************/
template EditorDOMPoint EditorBase::GetFirstIMESelectionStartPoint() const;
template EditorRawDOMPoint EditorBase::GetFirstIMESelectionStartPoint() const;
template EditorDOMPoint EditorBase::GetLastIMESelectionEndPoint() const;
template EditorRawDOMPoint EditorBase::GetLastIMESelectionEndPoint() const;

template Result<CreateContentResult, nsresult>
EditorBase::InsertNodeWithTransaction(nsIContent& aContentToInsert,
                                      const EditorDOMPoint& aPointToInsert);
template Result<CreateElementResult, nsresult>
EditorBase::InsertNodeWithTransaction(Element& aContentToInsert,
                                      const EditorDOMPoint& aPointToInsert);
template Result<CreateTextResult, nsresult>
EditorBase::InsertNodeWithTransaction(Text& aContentToInsert,
                                      const EditorDOMPoint& aPointToInsert);

template EditorDOMPoint EditorBase::GetFirstSelectionStartPoint() const;
template EditorRawDOMPoint EditorBase::GetFirstSelectionStartPoint() const;
template EditorDOMPoint EditorBase::GetFirstSelectionEndPoint() const;
template EditorRawDOMPoint EditorBase::GetFirstSelectionEndPoint() const;

template EditorBase::AutoCaretBidiLevelManager::AutoCaretBidiLevelManager(
    const EditorBase& aEditorBase, nsIEditor::EDirection aDirectionAndAmount,
    const EditorDOMPoint& aPointAtCaret);
template EditorBase::AutoCaretBidiLevelManager::AutoCaretBidiLevelManager(
    const EditorBase& aEditorBase, nsIEditor::EDirection aDirectionAndAmount,
    const EditorRawDOMPoint& aPointAtCaret);

EditorBase::EditorBase(EditorType aEditorType)
    : mEditActionData(nullptr),
      mPlaceholderName(nullptr),
      mModCount(0),
      mFlags(0),
      mUpdateCount(0),
      mPlaceholderBatch(0),
      mNewlineHandling(StaticPrefs::editor_singleLine_pasteNewlines()),
      mCaretStyle(StaticPrefs::layout_selection_caret_style()),
      mDocDirtyState(-1),
      mSpellcheckCheckboxState(eTriUnset),
      mInitSucceeded(false),
      mAllowsTransactionsToChangeSelection(true),
      mDidPreDestroy(false),
      mDidPostCreate(false),
      mDispatchInputEvent(true),
      mIsInEditSubAction(false),
      mHidingCaret(false),
      mSpellCheckerDictionaryUpdated(true),
      mIsHTMLEditorClass(aEditorType == EditorType::HTML) {
#ifdef XP_WIN
  if (!mCaretStyle && !IsTextEditor()) {
    // Wordpad-like caret behavior.
    mCaretStyle = 1;
  }
#endif  // #ifdef XP_WIN
  if (mNewlineHandling < nsIEditor::eNewlinesPasteIntact ||
      mNewlineHandling > nsIEditor::eNewlinesStripSurroundingWhitespace) {
    mNewlineHandling = nsIEditor::eNewlinesPasteToFirst;
  }
}

EditorBase::~EditorBase() {
  MOZ_ASSERT(!IsInitialized() || mDidPreDestroy,
             "Why PreDestroy hasn't been called?");

  if (mComposition) {
    mComposition->OnEditorDestroyed();
    mComposition = nullptr;
  }
  // If this editor is still hiding the caret, we need to restore it.
  HideCaret(false);
  mTransactionManager = nullptr;
}

NS_IMPL_CYCLE_COLLECTION_CLASS(EditorBase)

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(EditorBase)
  // Remove event listeners first since EditorEventListener may need
  // mDocument, mEventTarget, etc.
  if (tmp->mEventListener) {
    tmp->mEventListener->Disconnect();
    tmp->mEventListener = nullptr;
  }

  NS_IMPL_CYCLE_COLLECTION_UNLINK(mRootElement)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mSelectionController)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocument)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mIMEContentObserver)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mInlineSpellChecker)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mTextServicesDocument)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mTextInputListener)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mTransactionManager)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mActionListeners)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocStateListeners)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mEventTarget)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mPlaceholderTransaction)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mCachedDocumentEncoder)
  NS_IMPL_CYCLE_COLLECTION_UNLINK_WEAK_REFERENCE
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(EditorBase)
  Document* currentDoc =
      tmp->mRootElement ? tmp->mRootElement->GetUncomposedDoc() : nullptr;
  if (currentDoc && nsCCUncollectableMarker::InGeneration(
                        cb, currentDoc->GetMarkedCCGeneration())) {
    return NS_SUCCESS_INTERRUPTED_TRAVERSE;
  }
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mRootElement)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSelectionController)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocument)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mIMEContentObserver)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mInlineSpellChecker)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mTextServicesDocument)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mTextInputListener)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mTransactionManager)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mActionListeners)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocStateListeners)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEventTarget)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEventListener)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPlaceholderTransaction)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCachedDocumentEncoder)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(EditorBase)
  NS_INTERFACE_MAP_ENTRY(nsISelectionListener)
  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
  NS_INTERFACE_MAP_ENTRY(nsIEditor)
  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIEditor)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(EditorBase)
NS_IMPL_CYCLE_COLLECTING_RELEASE(EditorBase)

nsresult EditorBase::InitInternal(Document& aDocument, Element* aRootElement,
                                  nsISelectionController& aSelectionController,
                                  uint32_t aFlags) {
  MOZ_ASSERT_IF(
      !mEditActionData ||
          !mEditActionData->HasEditorDestroyedDuringHandlingEditAction(),
      GetTopLevelEditSubAction() == EditSubAction::eNone);

  // First only set flags, but other stuff shouldn't be initialized now.
  // Note that SetFlags() will be called by PostCreate().
  mFlags = aFlags;

  mDocument = &aDocument;
  // nsISelectionController should be stored only when we're a `TextEditor`.
  // Otherwise, in `HTMLEditor`, it's `PresShell`, and grabbing it causes
  // a circular reference and memory leak.
  // XXX Should we move `mSelectionController to `TextEditor`?
  MOZ_ASSERT_IF(!IsTextEditor(), &aSelectionController == GetPresShell());
  if (IsTextEditor()) {
    MOZ_ASSERT(&aSelectionController != GetPresShell());
    mSelectionController = &aSelectionController;
  }

  if (mEditActionData) {
    // During edit action, selection is cached. But this selection is invalid
    // now since selection controller is updated, so we have to update this
    // cache.
    Selection* selection = aSelectionController.GetSelection(
        nsISelectionController::SELECTION_NORMAL);
    NS_WARNING_ASSERTION(selection,
                         "SelectionController::GetSelection() failed");
    if (selection) {
      mEditActionData->UpdateSelectionCache(*selection);
    }
  }

  // set up root element if we are passed one.
  if (aRootElement) {
    mRootElement = aRootElement;
  }

  // If this is an editor for <input> or <textarea>, the text node which
  // has composition string is always recreated with same content. Therefore,
  // we need to nodify mComposition of text node destruction and replacing
  // composing string when this receives eCompositionChange event next time.
  if (mComposition && mComposition->GetContainerTextNode() &&
      !mComposition->GetContainerTextNode()->IsInComposedDoc()) {
    mComposition->OnTextNodeRemoved();
  }

  // Show the caret.
  DebugOnly<nsresult> rvIgnored = aSelectionController.SetCaretReadOnly(false);
  NS_WARNING_ASSERTION(
      NS_SUCCEEDED(rvIgnored),
      "nsISelectionController::SetCaretReadOnly(false) failed, but ignored");
  // Show all the selection reflected to user.
  rvIgnored =
      aSelectionController.SetSelectionFlags(nsISelectionDisplay::DISPLAY_ALL);
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rvIgnored),
                       "nsISelectionController::SetSelectionFlags("
                       "nsISelectionDisplay::DISPLAY_ALL) failed, but ignored");

  // Make sure that the editor will be destroyed properly
  mDidPreDestroy = false;
  // Make sure that the editor will be created properly
  mDidPostCreate = false;

  MOZ_ASSERT(IsBeingInitialized());

  AutoEditActionDataSetter editActionData(*this, EditAction::eInitializing);
  if (NS_WARN_IF(!editActionData.CanHandle())) {
    return NS_ERROR_FAILURE;
  }

  SelectionRef().AddSelectionListener(this);

  return NS_OK;
}

nsresult EditorBase::EnsureEmptyTextFirstChild() {
  MOZ_ASSERT(IsTextEditor());
  RefPtr<Element> root = GetRoot();
  nsIContent* firstChild = root->GetFirstChild();

  if (!firstChild || !firstChild->IsText()) {
    RefPtr<nsTextNode> newTextNode = CreateTextNode(u""_ns);
    if (!newTextNode) {
      NS_WARNING("EditorBase::CreateTextNode() failed");
      return NS_ERROR_UNEXPECTED;
    }
    IgnoredErrorResult ignoredError;
    root->InsertChildBefore(newTextNode, root->GetFirstChild(), true,
                            ignoredError);
    MOZ_ASSERT(!ignoredError.Failed());
  }

  return NS_OK;
}

nsresult EditorBase::PostCreateInternal() {
  MOZ_ASSERT(IsEditActionDataAvailable());

  // Synchronize some stuff for the flags.  SetFlags() will initialize
  // something by the flag difference.  This is first time of that, so, all
  // initializations must be run.  For such reason, we need to invert mFlags
  // value first.
  mFlags = ~mFlags;
  nsresult rv = SetFlags(~mFlags);
  if (NS_FAILED(rv)) {
    NS_WARNING("EditorBase::SetFlags() failed");
    return EditorBase::ToGenericNSResult(rv);
  }

  // These operations only need to happen on the first PostCreate call
  if (!mDidPostCreate) {
    mDidPostCreate = true;

    // Set up listeners
    CreateEventListeners();
    nsresult rv = InstallEventListeners();
    if (NS_FAILED(rv)) {
      NS_WARNING("EditorBase::InstallEventListeners() failed");
      return EditorBase::ToGenericNSResult(rv);
    }

    // nuke the modification count, so the doc appears unmodified
    // do this before we notify listeners
    DebugOnly<nsresult> rvIgnored = ResetModificationCount();
    NS_WARNING_ASSERTION(
        NS_SUCCEEDED(rvIgnored),
        "EditorBase::ResetModificationCount() failed, but ignored");

    // update the UI with our state
    rvIgnored = NotifyDocumentListeners(eDocumentCreated);
    NS_WARNING_ASSERTION(NS_SUCCEEDED(rvIgnored),
                         "EditorBase::NotifyDocumentListeners(eDocumentCreated)"
                         " failed, but ignored");
    rvIgnored = NotifyDocumentListeners(eDocumentStateChanged);
    NS_WARNING_ASSERTION(NS_SUCCEEDED(rvIgnored),
                         "EditorBase::NotifyDocumentListeners("
                         "eDocumentStateChanged) failed, but ignored");
  }

  // update nsTextStateManager and caret if we have focus
  if (RefPtr<Element> focusedElement = GetFocusedElement()) {
    DebugOnly<nsresult> rvIgnored = InitializeSelection(*focusedElement);
    NS_WARNING_ASSERTION(
        NS_SUCCEEDED(rvIgnored),
        "EditorBase::InitializeSelection() failed, but ignored");

    // If the text control gets reframed during focus, Focus() would not be
    // called, so take a chance here to see if we need to spell check the text
    // control.
    nsresult rv = FlushPendingSpellCheck();
    if (MOZ_UNLIKELY(rv == NS_ERROR_EDITOR_DESTROYED)) {
      NS_WARNING(
          "EditorBase::FlushPendingSpellCheck() caused destroying the editor");
      return EditorBase::ToGenericNSResult(NS_ERROR_EDITOR_DESTROYED);
    }
    NS_WARNING_ASSERTION(
        NS_SUCCEEDED(rv),
        "EditorBase::FlushPendingSpellCheck() failed, but ignored");

    IMEState newState;
    rv = GetPreferredIMEState(&newState);
    if (NS_FAILED(rv)) {
      NS_WARNING("EditorBase::GetPreferredIMEState() failed");
      return NS_OK;
    }
    IMEStateManager::UpdateIMEState(newState, focusedElement, *this);
  }

  // FYI: This call might cause destroying this editor.
  IMEStateManager::OnEditorInitialized(*this);

  return NS_OK;
}

void EditorBase::SetTextInputListener(TextInputListener* aTextInputListener) {
  MOZ_ASSERT(!mTextInputListener || !aTextInputListener ||
             mTextInputListener == aTextInputListener);
  mTextInputListener = aTextInputListener;
}

void EditorBase::SetIMEContentObserver(
    IMEContentObserver* aIMEContentObserver) {
  MOZ_ASSERT(!mIMEContentObserver || !aIMEContentObserver ||
             mIMEContentObserver == aIMEContentObserver);
  mIMEContentObserver = aIMEContentObserver;
}

void EditorBase::CreateEventListeners() {
  // Don't create the handler twice
  if (!mEventListener) {
    mEventListener = new EditorEventListener();
  }
}

nsresult EditorBase::InstallEventListeners() {
  // FIXME InstallEventListeners() should not be called if we failed to set
  // document or create an event listener.  So, these checks should be
  // MOZ_DIAGNOSTIC_ASSERT instead.
  MOZ_ASSERT(GetDocument());
  if (MOZ_UNLIKELY(!GetDocument()) || NS_WARN_IF(!mEventListener)) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  // Initialize the event target.
  mEventTarget = GetExposedRoot();
  if (NS_WARN_IF(!mEventTarget)) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  nsresult rv = mEventListener->Connect(this);
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
                       "EditorEventListener::Connect() failed");
  if (mComposition) {
    // If mComposition has already been destroyed, we should forget it.
    // This may happen if it ended while we don't listen to composition
    // events.
    if (mComposition->Destroyed()) {
      // XXX We may need to fix existing composition transaction here.
      //     However, this may be called when it's not safe.
      //     Perhaps, we should stop handling composition with events.
      mComposition = nullptr;
    }
    // Otherwise, Restart to handle composition with new editor contents.
    else {
      mComposition->StartHandlingComposition(this);
    }
  }
  return rv;
}

void EditorBase::RemoveEventListeners() {
  if (!mEventListener) {
    return;
  }
  mEventListener->Disconnect();
  if (mComposition) {
    // Even if this is called, don't release mComposition because this is
    // may be reused after reframing.
    mComposition->EndHandlingComposition(this);
  }
  mEventTarget = nullptr;
}

bool EditorBase::IsListeningToEvents() const {
  return mEventListener && !mEventListener->DetachedFromEditor();
}

bool EditorBase::GetDesiredSpellCheckState() {
  // Check user override on this element
  if (mSpellcheckCheckboxState != eTriUnset) {
    return (mSpellcheckCheckboxState == eTriTrue);
  }

  // Check user preferences
  int32_t spellcheckLevel = StaticPrefs::layout_spellcheckDefault();

  if (!spellcheckLevel) {
    return false;  // Spellchecking forced off globally
  }

  if (!CanEnableSpellCheck()) {
    return false;
  }

  PresShell* presShell = GetPresShell();
  if (presShell) {
    nsPresContext* context = presShell->GetPresContext();
    if (context && !context->IsDynamic()) {
      return false;
    }
  }

  // Check DOM state
  nsCOMPtr<nsIContent> content = GetExposedRoot();
  if (!content) {
    return false;
  }

  auto element = nsGenericHTMLElement::FromNode(content);
  if (!element) {
    return false;
  }

  // XXX I'm not sure whether we don't use this path when we're a plaintext mail
  // composer.
  if (IsHTMLEditor() && !AsHTMLEditor()->IsPlaintextMailComposer()) {
    // Some of the page content might be editable and some not, if spellcheck=
    // is explicitly set anywhere, so if there's anything editable on the page,
    // return true and let the spellchecker figure it out.
    Document* doc = content->GetComposedDoc();
    return doc && doc->IsEditingOn();
  }

  return element->Spellcheck();
}

void EditorBase::PreDestroyInternal() {
  MOZ_ASSERT(!mDidPreDestroy);

  mInitSucceeded = false;

  Selection* selection = GetSelection();
  if (selection) {
    selection->RemoveSelectionListener(this);
  }

  IMEStateManager::OnEditorDestroying(*this);

  // Let spellchecker clean up its observers etc. It is important not to
  // actually free the spellchecker here, since the spellchecker could have
  // caused flush notifications, which could have gotten here if a textbox
  // is being removed. Setting the spellchecker to nullptr could free the
  // object that is still in use! It will be freed when the editor is
  // destroyed.
  if (mInlineSpellChecker) {
    DebugOnly<nsresult> rvIgnored =
        mInlineSpellChecker->Cleanup(IsTextEditor());
    NS_WARNING_ASSERTION(
        NS_SUCCEEDED(rvIgnored),
        "mozInlineSpellChecker::Cleanup() failed, but ignored");
  }

  // tell our listeners that the doc is going away
  DebugOnly<nsresult> rvIgnored =
      NotifyDocumentListeners(eDocumentToBeDestroyed);
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rvIgnored),
                       "EditorBase::NotifyDocumentListeners("
                       "eDocumentToBeDestroyed) failed, but ignored");

  // Unregister event listeners
  RemoveEventListeners();
  // If this editor is still hiding the caret, we need to restore it.
  HideCaret(false);
  mActionListeners.Clear();
  mDocStateListeners.Clear();
  mInlineSpellChecker = nullptr;
  mTextServicesDocument = nullptr;
  mTextInputListener = nullptr;
  mSpellcheckCheckboxState = eTriUnset;
  mRootElement = nullptr;

  // Transaction may grab this instance.  Therefore, they should be released
  // here for stopping the circular reference with this instance.
  if (mTransactionManager) {
    DebugOnly<bool> disabledUndoRedo = DisableUndoRedo();
    NS_WARNING_ASSERTION(disabledUndoRedo,
                         "EditorBase::DisableUndoRedo() failed, but ignored");
    mTransactionManager = nullptr;
  }

  if (mEditActionData) {
    mEditActionData->OnEditorDestroy();
  }

  mDidPreDestroy = true;
}

NS_IMETHODIMP EditorBase::GetFlags(uint32_t* aFlags) {
  // NOTE: If you need to override this method, you need to make Flags()
  //       virtual.
  *aFlags = Flags();
  return NS_OK;
}

NS_IMETHODIMP EditorBase::SetFlags(uint32_t aFlags) {
  if (mFlags == aFlags) {
    return NS_OK;
  }

  // If we're a `TextEditor` instance, it's always a plaintext editor.
  // Therefore, `eEditorPlaintextMask` is not necessary and should not be set
  // for the performance reason.
  MOZ_ASSERT_IF(IsTextEditor(), !(aFlags & nsIEditor::eEditorPlaintextMask));
  // If we're an `HTMLEditor` instance, we cannot treat it as a single line
  // editor.  So, eEditorSingleLineMask is available only when we're a
  // `TextEditor` instance.
  MOZ_ASSERT_IF(IsHTMLEditor(), !(aFlags & nsIEditor::eEditorSingleLineMask));
  // If we're an `HTMLEditor` instance, we cannot treat it as a password editor.
  // So, eEditorPasswordMask is available only when we're a `TextEditor`
  // instance.
  MOZ_ASSERT_IF(IsHTMLEditor(), !(aFlags & nsIEditor::eEditorPasswordMask));
  // eEditorAllowInteraction changes the behavior of `HTMLEditor`.  So, it's
  // not available with `TextEditor` instance.
  MOZ_ASSERT_IF(IsTextEditor(), !(aFlags & nsIEditor::eEditorAllowInteraction));

  const bool isCalledByPostCreate = (mFlags == ~aFlags);
  // We don't support dynamic password flag change.
  MOZ_ASSERT_IF(!isCalledByPostCreate,
                !((mFlags ^ aFlags) & nsIEditor::eEditorPasswordMask));
  bool spellcheckerWasEnabled = !isCalledByPostCreate && CanEnableSpellCheck();
  mFlags = aFlags;

  if (!IsInitialized()) {
    // If we're initializing, we shouldn't do anything now.
    // SetFlags() will be called by PostCreate(),
    // we should synchronize some stuff for the flags at that time.
    return NS_OK;
  }

  // The flag change may cause the spellchecker state change
  if (CanEnableSpellCheck() != spellcheckerWasEnabled) {
    SyncRealTimeSpell();
  }

  // If this is called from PostCreate(), it will update the IME state if it's
  // necessary.
  if (!mDidPostCreate) {
    return NS_OK;
  }

  // Might be changing editable state, so, we need to reset current IME state
  // if we're focused and the flag change causes IME state change.
  if (RefPtr<Element> focusedElement = GetFocusedElement()) {
    IMEState newState;
    nsresult rv = GetPreferredIMEState(&newState);
    NS_WARNING_ASSERTION(
        NS_SUCCEEDED(rv),
        "EditorBase::GetPreferredIMEState() failed, but ignored");
    if (NS_SUCCEEDED(rv)) {
      // NOTE: When the enabled state isn't going to be modified, this method
      // is going to do nothing.
      IMEStateManager::UpdateIMEState(newState, focusedElement, *this);
    }
  }

  return NS_OK;
}

NS_IMETHODIMP EditorBase::GetIsSelectionEditable(bool* aIsSelectionEditable) {
  if (NS_WARN_IF(!aIsSelectionEditable)) {
    return NS_ERROR_INVALID_ARG;
  }
  *aIsSelectionEditable = IsSelectionEditable();
  return NS_OK;
}

bool EditorBase::IsSelectionEditable() {
  AutoEditActionDataSetter editActionData(*this, EditAction::eNotEditing);
  if (NS_WARN_IF(!editActionData.CanHandle())) {
    return false;
  }

  if (IsTextEditor()) {
    // XXX we just check that the anchor node is editable at the moment
    //     we should check that all nodes in the selection are editable
    const nsINode* anchorNode = SelectionRef().GetAnchorNode();
    return anchorNode && anchorNode->IsContent() && anchorNode->IsEditable();
  }

  const nsINode* anchorNode = SelectionRef().GetAnchorNode();
  const nsINode* focusNode = SelectionRef().GetFocusNode();
  if (!anchorNode || !focusNode) {
    return false;
  }

  // if anchorNode or focusNode is in a native anonymous subtree, HTMLEditor
  // shouldn't edit content in it.
  // XXX This must be a bug of Selection API.
  if (MOZ_UNLIKELY(anchorNode->IsInNativeAnonymousSubtree() ||
                   focusNode->IsInNativeAnonymousSubtree())) {
    return false;
  }

  // Per the editing spec as of June 2012: we have to have a selection whose
  // start and end nodes are editable, and which share an ancestor editing
  // host.  (Bug 766387.)
  bool isSelectionEditable = SelectionRef().RangeCount() &&
                             anchorNode->IsEditable() &&
                             focusNode->IsEditable();
  if (!isSelectionEditable) {
    return false;
  }

  const nsINode* commonAncestor =
      SelectionRef().GetAnchorFocusRange()->GetClosestCommonInclusiveAncestor();
  while (commonAncestor && !commonAncestor->IsEditable()) {
    commonAncestor = commonAncestor->GetParentNode();
  }
  // If there is no editable common ancestor, return false.
  return !!commonAncestor;
}

NS_IMETHODIMP EditorBase::GetIsDocumentEditable(bool* aIsDocumentEditable) {
  if (NS_WARN_IF(!aIsDocumentEditable)) {
    return NS_ERROR_INVALID_ARG;
  }
  RefPtr<Document> document = GetDocument();
  *aIsDocumentEditable = document && IsModifiable();
  return NS_OK;
}

NS_IMETHODIMP EditorBase::GetDocument(Document** aDocument) {
  if (NS_WARN_IF(!aDocument)) {
    return NS_ERROR_INVALID_ARG;
  }
  *aDocument = do_AddRef(mDocument).take();
  return NS_WARN_IF(!*aDocument) ? NS_ERROR_NOT_INITIALIZED : NS_OK;
}

already_AddRefed<nsIWidget> EditorBase::GetWidget() const {
  nsPresContext* presContext = GetPresContext();
  if (NS_WARN_IF(!presContext)) {
    return nullptr;
  }
  nsCOMPtr<nsIWidget> widget = presContext->GetRootWidget();
  return NS_WARN_IF(!widget) ? nullptr : widget.forget();
}

NS_IMETHODIMP EditorBase::GetContentsMIMEType(nsAString& aContentsMIMEType) {
  aContentsMIMEType = mContentMIMEType;
  return NS_OK;
}

NS_IMETHODIMP EditorBase::SetContentsMIMEType(
    const nsAString& aContentsMIMEType) {
  mContentMIMEType.Assign(aContentsMIMEType);
  return NS_OK;
}

NS_IMETHODIMP EditorBase::GetSelectionController(
    nsISelectionController** aSelectionController) {
  if (NS_WARN_IF(!aSelectionController)) {
    return NS_ERROR_INVALID_ARG;
  }
  *aSelectionController = do_AddRef(GetSelectionController()).take();
  return NS_WARN_IF(!*aSelectionController) ? NS_ERROR_FAILURE : NS_OK;
}

NS_IMETHODIMP EditorBase::DeleteSelection(EDirection aAction,
                                          EStripWrappers aStripWrappers) {
  nsresult rv = DeleteSelectionAsAction(aAction, aStripWrappers);
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
                       "EditorBase::DeleteSelectionAsAction() failed");
  return rv;
}

NS_IMETHODIMP EditorBase::GetSelection(Selection** aSelection) {
  nsresult rv = GetSelection(SelectionType::eNormal, aSelection);
  NS_WARNING_ASSERTION(
      NS_SUCCEEDED(rv),
      "EditorBase::GetSelection(SelectionType::eNormal) failed");
  return rv;
}

nsresult EditorBase::GetSelection(SelectionType aSelectionType,
                                  Selection** aSelection) const {
  if (NS_WARN_IF(!aSelection)) {
    return NS_ERROR_INVALID_ARG;
  }
  if (IsEditActionDataAvailable()) {
    *aSelection = do_AddRef(&SelectionRef()).take();
    return NS_OK;
  }
  nsISelectionController* selectionController = GetSelectionController();
  if (NS_WARN_IF(!selectionController)) {
    *aSelection = nullptr;
    return NS_ERROR_NOT_INITIALIZED;
  }
  *aSelection = do_AddRef(selectionController->GetSelection(
                              ToRawSelectionType(aSelectionType)))
                    .take();
  return NS_WARN_IF(!*aSelection) ? NS_ERROR_FAILURE : NS_OK;
}

nsresult EditorBase::DoTransactionInternal(nsITransaction* aTransaction) {
  MOZ_ASSERT(IsEditActionDataAvailable());
  MOZ_ASSERT_IF(
      // If the DOM is modified by a clipboard event handler,
      // HTMLEditor::OnModifyDocument() may need to do some transactions before
      // dispatching `beforeinput`.
      // FIXME: It shouldn't happen, and I think that it should be done once
      // before dispatching `input` event to hide the our editor hack from
      // the event listeners.
      GetEditAction() != EditAction::ePaste &&
          GetEditAction() != EditAction::eCut,
      !ShouldAlreadyHaveHandledBeforeInputEventDispatching());

  if (mPlaceholderBatch && !mPlaceholderTransaction) {
    MOZ_DIAGNOSTIC_ASSERT(mPlaceholderName);
    mPlaceholderTransaction = PlaceholderTransaction::Create(
        *this, *mPlaceholderName, std::move(mSelState));
    MOZ_ASSERT(mSelState.isNothing());

    // We will recurse, but will not hit this case in the nested call
    RefPtr<PlaceholderTransaction> placeholderTransaction =
        mPlaceholderTransaction;
    DebugOnly<nsresult> rvIgnored =
        DoTransactionInternal(placeholderTransaction);
    NS_WARNING_ASSERTION(
        NS_SUCCEEDED(rvIgnored),
        "EditorBase::DoTransactionInternal() failed, but ignored");

    if (mTransactionManager) {
      if (nsCOMPtr<nsITransaction> topTransaction =
              mTransactionManager->PeekUndoStack()) {
        if (RefPtr<EditTransactionBase> topTransactionBase =
                topTransaction->GetAsEditTransactionBase()) {
          if (PlaceholderTransaction* topPlaceholderTransaction =
                  topTransactionBase->GetAsPlaceholderTransaction()) {
            // there is a placeholder transaction on top of the undo stack.  It
            // is either the one we just created, or an earlier one that we are
            // now merging into.  From here on out remember this placeholder
            // instead of the one we just created.
            mPlaceholderTransaction = topPlaceholderTransaction;
          }
        }
      }
    }
  }

  if (aTransaction) {
    // XXX: Why are we doing selection specific batching stuff here?
    // XXX: Most entry points into the editor have auto variables that
    // XXX: should trigger Begin/EndUpdateViewBatch() calls that will make
    // XXX: these selection batch calls no-ops.
    // XXX:
    // XXX: I suspect that this was placed here to avoid multiple
    // XXX: selection changed notifications from happening until after
    // XXX: the transaction was done. I suppose that can still happen
    // XXX: if an embedding application called DoTransaction() directly
    // XXX: to pump its own transactions through the system, but in that
    // XXX: case, wouldn't we want to use Begin/EndUpdateViewBatch() or
    // XXX: its auto equivalent AutoUpdateViewBatch to ensure that
    // XXX: selection listeners have access to accurate frame data?
    // XXX:
    // XXX: Note that if we did add Begin/EndUpdateViewBatch() calls
    // XXX: we will need to make sure that they are disabled during
    // XXX: the init of the editor for text widgets to avoid layout
    // XXX: re-entry during initial reflow. - kin

    // get the selection and start a batch change
    SelectionBatcher selectionBatcher(SelectionRef(), __FUNCTION__);

    if (mTransactionManager) {
      RefPtr<TransactionManager> transactionManager(mTransactionManager);
      nsresult rv = transactionManager->DoTransaction(aTransaction);
      if (NS_FAILED(rv)) {
        NS_WARNING("TransactionManager::DoTransaction() failed");
        return rv;
      }
    } else {
      nsresult rv = aTransaction->DoTransaction();
      if (NS_FAILED(rv)) {
        NS_WARNING("nsITransaction::DoTransaction() failed");
        return rv;
      }
    }

    DoAfterDoTransaction(aTransaction);
  }

  return NS_OK;
}

NS_IMETHODIMP EditorBase::EnableUndo(bool aEnable) {
  // XXX Should we return NS_ERROR_FAILURE if EdnableUndoRedo() or
  //     DisableUndoRedo() returns false?
  if (aEnable) {
    DebugOnly<bool> enabledUndoRedo = EnableUndoRedo();
    NS_WARNING_ASSERTION(enabledUndoRedo,
                         "EditorBase::EnableUndoRedo() failed, but ignored");
    return NS_OK;
  }
  DebugOnly<bool> disabledUndoRedo = DisableUndoRedo();
  NS_WARNING_ASSERTION(disabledUndoRedo,
                       "EditorBase::DisableUndoRedo() failed, but ignored");
  return NS_OK;
}

NS_IMETHODIMP EditorBase::ClearUndoRedoXPCOM() {
  if (MOZ_UNLIKELY(!ClearUndoRedo())) {
    return NS_ERROR_FAILURE;  // We're handling a transaction
  }
  return NS_OK;
}

NS_IMETHODIMP EditorBase::Undo() {
  nsresult rv = UndoAsAction(1u);
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "EditorBase::UndoAsAction() failed");
  return rv;
}

NS_IMETHODIMP EditorBase::UndoAll() {
  if (!mTransactionManager) {
    return NS_OK;
  }
  size_t numberOfUndoItems = mTransactionManager->NumberOfUndoItems();
  if (!numberOfUndoItems) {
    return NS_OK;  // no transactions
  }
  nsresult rv = UndoAsAction(numberOfUndoItems);
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "EditorBase::UndoAsAction() failed");
  return rv;
}

NS_IMETHODIMP EditorBase::GetUndoRedoEnabled(bool* aIsEnabled) {
  MOZ_ASSERT(aIsEnabled);
  *aIsEnabled = IsUndoRedoEnabled();
  return NS_OK;
}

NS_IMETHODIMP EditorBase::GetCanUndo(bool* aCanUndo) {
  MOZ_ASSERT(aCanUndo);
  *aCanUndo = CanUndo();
  return NS_OK;
}

NS_IMETHODIMP EditorBase::Redo() {
  nsresult rv = RedoAsAction(1u);
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "EditorBase::RedoAsAction() failed");
  return rv;
}

NS_IMETHODIMP EditorBase::GetCanRedo(bool* aCanRedo) {
  MOZ_ASSERT(aCanRedo);
  *aCanRedo = CanRedo();
  return NS_OK;
}

nsresult EditorBase::UndoAsAction(uint32_t aCount, nsIPrincipal* aPrincipal) {
  if (aCount == 0 || IsReadonly()) {
    return NS_OK;
  }

  // If we don't have transaction in the undo stack, we shouldn't notify
  // anybody of trying to undo since it's not useful notification but we
  // need to pay some runtime cost.
  if (!CanUndo()) {
    return NS_OK;
  }

  // If there is composition, we shouldn't allow to undo with committing
  // composition since Chrome doesn't allow it and it doesn't make sense
  // because committing composition causes one transaction and Undo(1)
  // undoes the committing composition.
  if (GetComposition()) {
    return NS_OK;
  }

  AutoEditActionDataSetter editActionData(*this, EditAction::eUndo, aPrincipal);
  nsresult rv = editActionData.CanHandleAndMaybeDispatchBeforeInputEvent();
  if (NS_FAILED(rv)) {
    NS_WARNING_ASSERTION(rv == NS_ERROR_EDITOR_ACTION_CANCELED,
                         "CanHandleAndMaybeDispatchBeforeInputEvent() failed");
    return EditorBase::ToGenericNSResult(rv);
  }

  AutoUpdateViewBatch preventSelectionChangeEvent(*this, __FUNCTION__);

  NotifyEditorObservers(eNotifyEditorObserversOfBefore);
  if (NS_WARN_IF(!CanUndo()) || NS_WARN_IF(Destroyed())) {
    return NS_ERROR_FAILURE;
  }

  rv = NS_OK;
  {
    IgnoredErrorResult ignoredError;
    AutoEditSubActionNotifier startToHandleEditSubAction(
        *this, EditSubAction::eUndo, nsIEditor::eNone, ignoredError);
    if (NS_WARN_IF(ignoredError.ErrorCodeIs(NS_ERROR_EDITOR_DESTROYED))) {
      return EditorBase::ToGenericNSResult(ignoredError.StealNSResult());
    }
    NS_WARNING_ASSERTION(!ignoredError.Failed(),
                         "TextEditor::OnStartToHandleTopLevelEditSubAction() "
                         "failed, but ignored");

    RefPtr<TransactionManager> transactionManager(mTransactionManager);
    for (uint32_t i = 0; i < aCount; ++i) {
      if (NS_FAILED(transactionManager->Undo())) {
        NS_WARNING("TransactionManager::Undo() failed");
        break;
      }
      DoAfterUndoTransaction();
    }

    if (IsHTMLEditor()) {
      rv = AsHTMLEditor()->ReflectPaddingBRElementForEmptyEditor();
    }
  }

  NotifyEditorObservers(eNotifyEditorObserversOfEnd);
  return EditorBase::ToGenericNSResult(rv);
}

nsresult EditorBase::RedoAsAction(uint32_t aCount, nsIPrincipal* aPrincipal) {
  if (aCount == 0 || IsReadonly()) {
    return NS_OK;
  }

  // If we don't have transaction in the redo stack, we shouldn't notify
  // anybody of trying to redo since it's not useful notification but we
  // need to pay some runtime cost.
  if (!CanRedo()) {
    return NS_OK;
  }

  // If there is composition, we shouldn't allow to redo with committing
  // composition since Chrome doesn't allow it and it doesn't make sense
  // because committing composition causes removing all transactions from
  // the redo queue.  So, it becomes impossible to redo anything.
  if (GetComposition()) {
    return NS_OK;
  }

  AutoEditActionDataSetter editActionData(*this, EditAction::eRedo, aPrincipal);
  nsresult rv = editActionData.CanHandleAndMaybeDispatchBeforeInputEvent();
  if (NS_FAILED(rv)) {
    NS_WARNING_ASSERTION(rv == NS_ERROR_EDITOR_ACTION_CANCELED,
                         "CanHandleAndMaybeDispatchBeforeInputEvent() failed");
    return EditorBase::ToGenericNSResult(rv);
  }

  AutoUpdateViewBatch preventSelectionChangeEvent(*this, __FUNCTION__);

  NotifyEditorObservers(eNotifyEditorObserversOfBefore);
  if (NS_WARN_IF(!CanRedo()) || NS_WARN_IF(Destroyed())) {
    return NS_ERROR_FAILURE;
  }

  rv = NS_OK;
  {
    IgnoredErrorResult ignoredError;
    AutoEditSubActionNotifier startToHandleEditSubAction(
        *this, EditSubAction::eRedo, nsIEditor::eNone, ignoredError);
    if (NS_WARN_IF(ignoredError.ErrorCodeIs(NS_ERROR_EDITOR_DESTROYED))) {
      return ignoredError.StealNSResult();
    }
    NS_WARNING_ASSERTION(!ignoredError.Failed(),
                         "TextEditor::OnStartToHandleTopLevelEditSubAction() "
                         "failed, but ignored");

    RefPtr<TransactionManager> transactionManager(mTransactionManager);
    for (uint32_t i = 0; i < aCount; ++i) {
      if (NS_FAILED(transactionManager->Redo())) {
        NS_WARNING("TransactionManager::Redo() failed");
        break;
      }
      DoAfterRedoTransaction();
    }

    if (IsHTMLEditor()) {
      rv = AsHTMLEditor()->ReflectPaddingBRElementForEmptyEditor();
    }
  }

  NotifyEditorObservers(eNotifyEditorObserversOfEnd);
  return EditorBase::ToGenericNSResult(rv);
}

NS_IMETHODIMP EditorBase::BeginTransaction() {
  AutoEditActionDataSetter editActionData(*this, EditAction::eUnknown);
  if (NS_WARN_IF(!editActionData.CanHandle())) {
    return NS_ERROR_FAILURE;
  }

  BeginTransactionInternal(__FUNCTION__);
  return NS_OK;
}

void EditorBase::BeginTransactionInternal(const char* aRequesterFuncName) {
  BeginUpdateViewBatch(aRequesterFuncName);

  if (NS_WARN_IF(!mTransactionManager)) {
    return;
  }

  RefPtr<TransactionManager> transactionManager(mTransactionManager);
  DebugOnly<nsresult> rvIgnored = transactionManager->BeginBatch(nullptr);
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rvIgnored),
                       "TransactionManager::BeginBatch() failed, but ignored");
}

NS_IMETHODIMP EditorBase::EndTransaction() {
  AutoEditActionDataSetter editActionData(*this, EditAction::eUnknown);
  if (NS_WARN_IF(!editActionData.CanHandle())) {
    return NS_ERROR_FAILURE;
  }

  EndTransactionInternal(__FUNCTION__);
  return NS_OK;
}

void EditorBase::EndTransactionInternal(const char* aRequesterFuncName) {
  if (mTransactionManager) {
    RefPtr<TransactionManager> transactionManager(mTransactionManager);
    DebugOnly<nsresult> rvIgnored = transactionManager->EndBatch(false);
    NS_WARNING_ASSERTION(NS_SUCCEEDED(rvIgnored),
                         "TransactionManager::EndBatch() failed, but ignored");
  }

  EndUpdateViewBatch(aRequesterFuncName);
}

void EditorBase::BeginPlaceholderTransaction(nsStaticAtom& aTransactionName,
                                             const char* aRequesterFuncName) {
  MOZ_ASSERT(IsEditActionDataAvailable());
  MOZ_ASSERT(mPlaceholderBatch >= 0, "negative placeholder batch count!");

  if (!mPlaceholderBatch) {
    NotifyEditorObservers(eNotifyEditorObserversOfBefore);
    // time to turn on the batch
    BeginUpdateViewBatch(aRequesterFuncName);
    mPlaceholderTransaction = nullptr;
    mPlaceholderName = &aTransactionName;
    mSelState.emplace();
    mSelState->SaveSelection(SelectionRef());
    // Composition transaction can modify multiple nodes and it merges text
    // node for ime into single text node.
    // So if current selection is into IME text node, it might be failed
    // to restore selection by UndoTransaction.
    // So we need update selection by range updater.
    if (mPlaceholderName == nsGkAtoms::IMETxnName) {
      RangeUpdaterRef().RegisterSelectionState(*mSelState);
    }
  }
  mPlaceholderBatch++;
}

void EditorBase::EndPlaceholderTransaction(
    ScrollSelectionIntoView aScrollSelectionIntoView,
    const char* aRequesterFuncName) {
  MOZ_ASSERT(IsEditActionDataAvailable());
  MOZ_ASSERT(mPlaceholderBatch > 0,
             "zero or negative placeholder batch count when ending batch!");

  if (!(--mPlaceholderBatch)) {
    // By making the assumption that no reflow happens during the calls
    // to EndUpdateViewBatch and ScrollSelectionFocusIntoView, we are able to
    // allow the selection to cache a frame offset which is used by the
    // caret drawing code. We only enable this cache here; at other times,
    // we have no way to know whether reflow invalidates it
    // See bugs 35296 and 199412.
    SelectionRef().SetCanCacheFrameOffset(true);

    // time to turn off the batch
    EndUpdateViewBatch(aRequesterFuncName);
    // make sure selection is in view

    // After ScrollSelectionFocusIntoView(), the pending notifications might be
    // flushed and PresShell/PresContext/Frames may be dead. See bug 418470.
    // XXX Even if we're destroyed, we need to keep handling below because
    //     this method changes a lot of status.  We should rewrite this safer.
    if (aScrollSelectionIntoView == ScrollSelectionIntoView::Yes) {
      DebugOnly<nsresult> rvIgnored = ScrollSelectionFocusIntoView();
      NS_WARNING_ASSERTION(
          NS_SUCCEEDED(rvIgnored),
          "EditorBase::ScrollSelectionFocusIntoView() failed, but Ignored");
    }

    // cached for frame offset are Not available now
    SelectionRef().SetCanCacheFrameOffset(false);

    if (mSelState) {
      // we saved the selection state, but never got to hand it to placeholder
      // (else we ould have nulled out this pointer), so destroy it to prevent
      // leaks.
      if (mPlaceholderName == nsGkAtoms::IMETxnName) {
        RangeUpdaterRef().DropSelectionState(*mSelState);
      }
      mSelState.reset();
    }
    // We might have never made a placeholder if no action took place.
    if (mPlaceholderTransaction) {
      // FYI: Disconnect placeholder transaction before dispatching "input"
      //      event because an input event listener may start other things.
      // TODO: We should forget EditActionDataSetter too.
      RefPtr<PlaceholderTransaction> placeholderTransaction =
          std::move(mPlaceholderTransaction);
      DebugOnly<nsresult> rvIgnored =
          placeholderTransaction->EndPlaceHolderBatch();
      NS_WARNING_ASSERTION(
          NS_SUCCEEDED(rvIgnored),
          "PlaceholderTransaction::EndPlaceHolderBatch() failed, but ignored");
      // notify editor observers of action but if composing, it's done by
      // compositionchange event handler.
      if (!mComposition) {
        NotifyEditorObservers(eNotifyEditorObserversOfEnd);
      }
    } else {
      NotifyEditorObservers(eNotifyEditorObserversOfCancel);
    }
  }
}

NS_IMETHODIMP EditorBase::GetDocumentIsEmpty(bool* aDocumentIsEmpty) {
  MOZ_ASSERT(aDocumentIsEmpty);
  *aDocumentIsEmpty = IsEmpty();
  return NS_OK;
}

// XXX: The rule system should tell us which node to select all on (ie, the
//      root, or the body)
NS_IMETHODIMP EditorBase::SelectAll() {
  AutoEditActionDataSetter editActionData(*this, EditAction::eNotEditing);
  if (NS_WARN_IF(!editActionData.CanHandle())) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  nsresult rv = SelectAllInternal();
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "SelectAllInternal() failed");
  // This is low level API for XUL applcation.  So, we should return raw
  // error code here.
  return rv;
}

nsresult EditorBase::SelectAllInternal() {
  MOZ_ASSERT(IsInitialized());

  DebugOnly<nsresult> rvIgnored = CommitComposition();
  if (NS_WARN_IF(Destroyed())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rvIgnored),
                       "EditorBase::CommitComposition() failed, but ignored");

  // XXX Do we need to keep handling after committing composition causes moving
  //     focus to different element?  Although TextEditor has independent
  //     selection, so, we may not see any odd behavior even in such case.

  nsresult rv = SelectEntireDocument();
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
                       "EditorBase::SelectEntireDocument() failed");
  return rv;
}

MOZ_CAN_RUN_SCRIPT_BOUNDARY NS_IMETHODIMP EditorBase::BeginningOfDocument() {
  MOZ_ASSERT(IsTextEditor());

  AutoEditActionDataSetter editActionData(*this, EditAction::eNotEditing);
  if (NS_WARN_IF(!editActionData.CanHandle())) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  // get the root element
  RefPtr<Element> rootElement = GetRoot();
  if (NS_WARN_IF(!rootElement)) {
    return NS_ERROR_NULL_POINTER;
  }

  // find first editable thingy
  nsCOMPtr<nsIContent> firstEditableLeaf;
  // If we're `TextEditor`, the first editable leaf node is a text node or
  // padding `<br>` element.  In the first case, we need to collapse selection
  // into it.
  if (rootElement->GetFirstChild() && rootElement->GetFirstChild()->IsText()) {
    firstEditableLeaf = rootElement->GetFirstChild();
  }
  if (!firstEditableLeaf) {
    // just the root node, set selection to inside the root
    nsresult rv = CollapseSelectionToStartOf(*rootElement);
    NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
                         "EditorBase::CollapseSelectionToStartOf() failed");
    return rv;
  }

  if (firstEditableLeaf->IsText()) {
    // If firstEditableLeaf is text, set selection to beginning of the text
    // node.
    nsresult rv = CollapseSelectionToStartOf(*firstEditableLeaf);
    NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
                         "EditorBase::CollapseSelectionToStartOf() failed");
    return rv;
  }

  // Otherwise, it's a leaf node and we set the selection just in front of it.
  nsCOMPtr<nsIContent> parent = firstEditableLeaf->GetParent();
  if (NS_WARN_IF(!parent)) {
    return NS_ERROR_NULL_POINTER;
  }

  MOZ_ASSERT(
      parent->ComputeIndexOf(firstEditableLeaf).valueOr(UINT32_MAX) == 0,
      "How come the first node isn't the left most child in its parent?");
  nsresult rv = CollapseSelectionToStartOf(*parent);
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
                       "EditorBase::CollapseSelectionToStartOf() failed");
  return rv;
}

NS_IMETHODIMP EditorBase::EndOfDocument() { return NS_ERROR_NOT_IMPLEMENTED; }

NS_IMETHODIMP EditorBase::GetDocumentModified(bool* aOutDocModified) {
  if (NS_WARN_IF(!aOutDocModified)) {
    return NS_ERROR_INVALID_ARG;
  }

  int32_t modCount = 0;
  DebugOnly<nsresult> rvIgnored = GetModificationCount(&modCount);
  NS_WARNING_ASSERTION(
      NS_SUCCEEDED(rvIgnored),
      "EditorBase::GetModificationCount() failed, but ignored");

  *aOutDocModified = (modCount != 0);
  return NS_OK;
}

NS_IMETHODIMP EditorBase::GetDocumentCharacterSet(nsACString& aCharacterSet) {
  return NS_ERROR_NOT_AVAILABLE;
}

nsresult EditorBase::GetDocumentCharsetInternal(nsACString& aCharset) const {
  Document* document = GetDocument();
  if (NS_WARN_IF(!document)) {
    return NS_ERROR_NOT_INITIALIZED;
  }
  document->GetDocumentCharacterSet()->Name(aCharset);
  return NS_OK;
}

NS_IMETHODIMP EditorBase::SetDocumentCharacterSet(
    const nsACString& aCharacterSet) {
  return NS_ERROR_NOT_AVAILABLE;
}

NS_IMETHODIMP EditorBase::OutputToString(const nsAString& aFormatType,
                                         uint32_t aDocumentEncoderFlags,
                                         nsAString& aOutputString) {
  AutoEditActionDataSetter editActionData(*this, EditAction::eNotEditing);
  if (NS_WARN_IF(!editActionData.CanHandle())) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  nsresult rv =
      ComputeValueInternal(aFormatType, aDocumentEncoderFlags, aOutputString);
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
                       "EditorBase::ComputeValueInternal() failed");
  // This is low level API for XUL application.  So, we should return raw
  // error code here.
  return rv;
}

nsresult EditorBase::ComputeValueInternal(const nsAString& aFormatType,
                                          uint32_t aDocumentEncoderFlags,
                                          nsAString& aOutputString) const {
  MOZ_ASSERT(IsEditActionDataAvailable());

  // First, let's try to get the value simply only from text node if the
  // caller wants plaintext value.
  if (aFormatType.LowerCaseEqualsLiteral("text/plain") &&
      !(aDocumentEncoderFlags & (nsIDocumentEncoder::OutputSelectionOnly |
                                 nsIDocumentEncoder::OutputWrap))) {
    // Shortcut for empty editor case.
    if (IsEmpty()) {
      aOutputString.Truncate();
      return NS_OK;
    }
    // NOTE: If it's neither <input type="text"> nor <textarea>, e.g., an HTML
    // editor which is in plaintext mode (e.g., plaintext email composer on
    // Thunderbird), it should be handled by the expensive path.
    if (IsTextEditor()) {
      // If it's necessary to check selection range or the editor wraps hard,
      // we need some complicated handling.  In such case, we need to use the
      // expensive path.
      // XXX Anything else what we cannot return the text node data simply?
      Result<EditActionResult, nsresult> result =
          AsTextEditor()->ComputeValueFromTextNodeAndBRElement(aOutputString);
      if (MOZ_UNLIKELY(result.isErr())) {
        NS_WARNING("TextEditor::ComputeValueFromTextNodeAndBRElement() failed");
        return result.unwrapErr();
      }
      if (!result.inspect().Ignored()) {
        return NS_OK;
      }
    }
  }

  nsAutoCString charset;
  nsresult rv = GetDocumentCharsetInternal(charset);
  if (NS_FAILED(rv) || charset.IsEmpty()) {
    charset.AssignLiteral("windows-1252");  // XXX Why don't we use "UTF-8"?
  }

  nsCOMPtr<nsIDocumentEncoder> encoder =
      GetAndInitDocEncoder(aFormatType, aDocumentEncoderFlags, charset);
  if (!encoder) {
    NS_WARNING("EditorBase::GetAndInitDocEncoder() failed");
    return NS_ERROR_FAILURE;
  }

  rv = encoder->EncodeToString(aOutputString);
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
                       "nsIDocumentEncoder::EncodeToString() failed");
  return rv;
}

already_AddRefed<nsIDocumentEncoder> EditorBase::GetAndInitDocEncoder(
    const nsAString& aFormatType, uint32_t aDocumentEncoderFlags,
    const nsACString& aCharset) const {
  MOZ_ASSERT(IsEditActionDataAvailable());

  nsCOMPtr<nsIDocumentEncoder> docEncoder;
  if (!mCachedDocumentEncoder ||
      !mCachedDocumentEncoderType.Equals(aFormatType)) {
    nsAutoCString formatType;
    LossyAppendUTF16toASCII(aFormatType, formatType);
    docEncoder = do_createDocumentEncoder(PromiseFlatCString(formatType).get());
    if (NS_WARN_IF(!docEncoder)) {
      return nullptr;
    }
    mCachedDocumentEncoder = docEncoder;
    mCachedDocumentEncoderType = aFormatType;
  } else {
    docEncoder = mCachedDocumentEncoder;
  }

  RefPtr<Document> doc = GetDocument();
  NS_ASSERTION(doc, "Need a document");

  nsresult rv = docEncoder->NativeInit(
      doc, aFormatType,
      aDocumentEncoderFlags | nsIDocumentEncoder::RequiresReinitAfterOutput);
  if (NS_FAILED(rv)) {
    NS_WARNING("nsIDocumentEncoder::NativeInit() failed");
    return nullptr;
  }

  if (!aCharset.IsEmpty() && !aCharset.EqualsLiteral("null")) {
    DebugOnly<nsresult> rvIgnored = docEncoder->SetCharset(aCharset);
    NS_WARNING_ASSERTION(
        NS_SUCCEEDED(rvIgnored),
        "nsIDocumentEncoder::SetCharset() failed, but ignored");
  }

  const int32_t wrapWidth = std::max(WrapWidth(), 0);
  DebugOnly<nsresult> rvIgnored = docEncoder->SetWrapColumn(wrapWidth);
  NS_WARNING_ASSERTION(
      NS_SUCCEEDED(rvIgnored),
      "nsIDocumentEncoder::SetWrapColumn() failed, but ignored");

  // Set the selection, if appropriate.
  // We do this either if the OutputSelectionOnly flag is set,
  // in which case we use our existing selection ...
  if (aDocumentEncoderFlags & nsIDocumentEncoder::OutputSelectionOnly) {
    if (NS_FAILED(docEncoder->SetSelection(&SelectionRef()))) {
      NS_WARNING("nsIDocumentEncoder::SetSelection() failed");
      return nullptr;
    }
  }
  // ... or if the root element is not a body,
  // in which case we set the selection to encompass the root.
  else {
    Element* rootElement = GetRoot();
    if (NS_WARN_IF(!rootElement)) {
      return nullptr;
    }
    if (!rootElement->IsHTMLElement(nsGkAtoms::body)) {
      if (NS_FAILED(docEncoder->SetContainerNode(rootElement))) {
        NS_WARNING("nsIDocumentEncoder::SetContainerNode() failed");
        return nullptr;
      }
    }
  }

  return docEncoder.forget();
}

bool EditorBase::AreClipboardCommandsUnconditionallyEnabled() const {
  Document* document = GetDocument();
  return document && document->AreClipboardCommandsUnconditionallyEnabled();
}

bool EditorBase::CheckForClipboardCommandListener(
    nsAtom* aCommand, EventMessage aEventMessage) const {
  RefPtr<Document> document = GetDocument();
  if (!document) {
    return false;
  }

  // We exclude XUL and chrome docs here to maintain current behavior where
  // in these cases the editor element alone is expected to handle clipboard
  // command availability.
  if (!document->AreClipboardCommandsUnconditionallyEnabled()) {
    return false;
  }

  // So in web content documents, "unconditionally" enabled Cut/Copy are not
  // really unconditional; they're enabled if there is a listener that wants
  // to handle them. What they're not conditional on here is whether there is
  // currently a selection in the editor.
  RefPtr<PresShell> presShell = document->GetObservingPresShell();
  if (!presShell) {
    return false;
  }
  RefPtr<nsPresContext> presContext = presShell->GetPresContext();
  if (!presContext) {
    return false;
  }

  RefPtr<EventTarget> et = IsHTMLEditor()
                               ? AsHTMLEditor()->ComputeEditingHost(
                                     HTMLEditor::LimitInBodyElement::No)
                               : GetDOMEventTarget();

  while (et) {
    EventListenerManager* elm = et->GetExistingListenerManager();
    if (elm && elm->HasListenersFor(aCommand)) {
      return true;
    }
    InternalClipboardEvent event(true, aEventMessage);
    EventChainPreVisitor visitor(presContext, &event, nullptr,
                                 nsEventStatus_eIgnore, false, et);
    et->GetEventTargetParent(visitor);
    et = visitor.GetParentTarget();
  }

  return false;
}

already_AddRefed<DataTransfer> EditorBase::CreateDataTransferForPaste(
    EventMessage aEventMessage,
    nsIClipboard::ClipboardType aClipboardType) const {
  nsIGlobalObject* scopeObject = nullptr;
  if (PresShell* presShell = GetPresShell()) {
    if (Document* doc = presShell->GetDocument()) {
      scopeObject = doc->GetScopeObject();
    }
  }

  auto dataTransfer = MakeRefPtr<DataTransfer>(scopeObject, aEventMessage, true,
                                               Some(aClipboardType));
  return dataTransfer.forget();
}

Result<EditorBase::ClipboardEventResult, nsresult>
EditorBase::DispatchClipboardEventAndUpdateClipboard(
    EventMessage aEventMessage,
    Maybe<nsIClipboard::ClipboardType> aClipboardType,
    DataTransfer* aDataTransfer /* = nullptr */) {
  MOZ_ASSERT(IsEditActionDataAvailable());

  // Clipboard events are fired before `beforeinput` event.  Therefore, we
  // need to forget mLastCollapsibleWhiteSpaceAppendedTextNode here to avoid
  // infinite loop caused by the hack.
  if (IsHTMLEditor()) {
    AsHTMLEditor()->mLastCollapsibleWhiteSpaceAppendedTextNode = nullptr;
  }

  const bool isPasting =
      aEventMessage == ePaste || aEventMessage == ePasteNoFormatting;
  if (isPasting) {
    CommitComposition();
    if (NS_WARN_IF(Destroyed())) {
      return Err(NS_ERROR_EDITOR_DESTROYED);
    }
  }

  RefPtr<PresShell> presShell = GetPresShell();
  if (NS_WARN_IF(!presShell)) {
    return Err(NS_ERROR_NOT_AVAILABLE);
  }

  const RefPtr<Selection> sel = [&]() {
    if (IsHTMLEditor() && aEventMessage == eCopy &&
        SelectionRef().IsCollapsed()) {
      // If we don't have a usable selection for copy and we're an HTML
      // editor (which is global for the document) try to use the last
      // focused selection instead.
      return nsCopySupport::GetSelectionForCopy(GetDocument());
    }
    return do_AddRef(&SelectionRef());
  }();

  bool actionTaken = false;
  const bool doDefault = nsCopySupport::FireClipboardEvent(
      aEventMessage, aClipboardType, presShell, sel, aDataTransfer,
      &actionTaken);
  NotifyOfDispatchingClipboardEvent();

  if (NS_WARN_IF(Destroyed())) {
    return Err(NS_ERROR_EDITOR_DESTROYED);
  }

  if (doDefault) {
    MOZ_ASSERT(actionTaken);
    return ClipboardEventResult::DoDefault;
  }
  // If we handle a "paste" and nsCopySupport::FireClipboardEvent sets
  // actionTaken to "false" means that it's an error.  Otherwise, the "paste"
  // event is just canceled.
  if (isPasting) {
    return actionTaken ? ClipboardEventResult::DefaultPreventedOfPaste
                       : ClipboardEventResult::IgnoredOrError;
  }
  // If we handle a "copy", actionTaken is set to true only when
  // nsCopySupport::FireClipboardEvent does not meet an error.
  // If we handle a "cut", actionTaken is set to true only when
  // nsCopySupport::FireClipboardEvent does not meet an error and
  // - the selection is collapsed in editable elements when the event is not
  //   canceled.
  // - the event is canceled but update the clipboard with the dataTransfer
  //   of the event.
  return actionTaken ? ClipboardEventResult::CopyOrCutHandled
                     : ClipboardEventResult::IgnoredOrError;
}

NS_IMETHODIMP EditorBase::Cut() {
  nsresult rv = CutAsAction();
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "EditorBase::CutAsAction() failed");
  return rv;
}

nsresult EditorBase::CutAsAction(nsIPrincipal* aPrincipal) {
  AutoEditActionDataSetter editActionData(*this, EditAction::eCut, aPrincipal);
  if (NS_WARN_IF(!editActionData.CanHandle())) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  {
    RefPtr<nsFocusManager> focusManager = nsFocusManager::GetFocusManager();
    if (NS_WARN_IF(!focusManager)) {
      return NS_ERROR_UNEXPECTED;
    }
    const RefPtr<Element> focusedElement = focusManager->GetFocusedElement();

    Result<ClipboardEventResult, nsresult> ret =
        DispatchClipboardEventAndUpdateClipboard(
            eCut, Some(nsIClipboard::kGlobalClipboard));
    if (MOZ_UNLIKELY(ret.isErr())) {
      NS_WARNING(
          "EditorBase::DispatchClipboardEventAndUpdateClipboard(eCut, "
          "nsIClipboard::kGlobalClipboard) failed");
      return EditorBase::ToGenericNSResult(ret.unwrapErr());
    }
    switch (ret.unwrap()) {
      case ClipboardEventResult::DoDefault:
        break;
      case ClipboardEventResult::CopyOrCutHandled:
        return NS_OK;
      case ClipboardEventResult::IgnoredOrError:
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