editor/libeditor/TextEditRules.cpp
author Masayuki Nakano <masayuki@d-toybox.com>
Thu, 25 Oct 2018 03:35:26 +0000
changeset 499365 ca2018e79dc07aef83d62d70905e64895bc607a2
parent 485080 7ae524e2f7746b2260163d6e3decfba3c3100a54
child 499418 f01896424c3a2fa77c20f9b9b40da89a2a09c1ba
permissions -rw-r--r--
Bug 1501180 - Make TextEditRules::Notify() hide input characters via editor instance r=m_kato TextEditRules::Notify() is callback of the timer. Therefore, this won't be in the stack while editor handles an edit action. Then, TextEditRules cannot access edit action data which will be put on the stack after fixing bug 1465702. So, it should do it after once calling a method of editor instance (and editor instance should call back proper TextEditRules method). Differential Revision: https://phabricator.services.mozilla.com/D9502

/* -*- 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 "mozilla/TextEditRules.h"

#include "HTMLEditRules.h"
#include "TextEditUtils.h"
#include "mozilla/Assertions.h"
#include "mozilla/EditAction.h"
#include "mozilla/EditorDOMPoint.h"
#include "mozilla/EditorUtils.h"
#include "mozilla/LookAndFeel.h"
#include "mozilla/Preferences.h"
#include "mozilla/TextComposition.h"
#include "mozilla/TextEditor.h"
#include "mozilla/dom/Element.h"
#include "mozilla/dom/NodeFilterBinding.h"
#include "mozilla/dom/NodeIterator.h"
#include "mozilla/dom/Selection.h"
#include "nsAString.h"
#include "nsCOMPtr.h"
#include "nsCRT.h"
#include "nsCRTGlue.h"
#include "nsComponentManagerUtils.h"
#include "nsContentUtils.h"
#include "nsDebug.h"
#include "nsError.h"
#include "nsGkAtoms.h"
#include "nsIContent.h"
#include "nsIDocumentEncoder.h"
#include "nsNameSpaceManager.h"
#include "nsINode.h"
#include "nsIPlaintextEditor.h"
#include "nsISupportsBase.h"
#include "nsLiteralString.h"
#include "nsTextNode.h"
#include "nsUnicharUtils.h"
#include "nsIHTMLCollection.h"
#include "nsPrintfCString.h"

namespace mozilla {

using namespace dom;

template CreateElementResult
TextEditRules::CreateBRInternal(const EditorDOMPoint& aPointToInsert,
                                bool aCreateMozBR);
template CreateElementResult
TextEditRules::CreateBRInternal(const EditorRawDOMPoint& aPointToInsert,
                                bool aCreateMozBR);

#define CANCEL_OPERATION_IF_READONLY_OR_DISABLED \
  if (IsReadonly() || IsDisabled()) \
  {                     \
    *aCancel = true; \
    return NS_OK;       \
  };

/********************************************************
 * mozilla::TextEditRules
 ********************************************************/

TextEditRules::TextEditRules()
  : mTextEditor(nullptr)
  , mData(nullptr)
  , mPasswordIMEIndex(0)
  , mCachedSelectionOffset(0)
  , mActionNesting(0)
  , mLockRulesSniffing(false)
  , mDidExplicitlySetInterline(false)
  , mDeleteBidiImmediately(false)
  , mIsHTMLEditRules(false)
  , mTopLevelEditSubAction(EditSubAction::eNone)
  , mLastStart(0)
  , mLastLength(0)
{
  InitFields();
}

void
TextEditRules::InitFields()
{
  mTextEditor = nullptr;
  mPasswordText.Truncate();
  mPasswordIMEText.Truncate();
  mPasswordIMEIndex = 0;
  mBogusNode = nullptr;
  mCachedSelectionNode = nullptr;
  mCachedSelectionOffset = 0;
  mActionNesting = 0;
  mLockRulesSniffing = false;
  mDidExplicitlySetInterline = false;
  mDeleteBidiImmediately = false;
  mTopLevelEditSubAction = EditSubAction::eNone;
  mTimer = nullptr;
  mLastStart = 0;
  mLastLength = 0;
}

TextEditRules::~TextEditRules()
{
   // do NOT delete mTextEditor here.  We do not hold a ref count to
   // mTextEditor.  mTextEditor owns our lifespan.

  if (mTimer) {
    mTimer->Cancel();
  }
}

HTMLEditRules*
TextEditRules::AsHTMLEditRules()
{
  return mIsHTMLEditRules ? static_cast<HTMLEditRules*>(this) : nullptr;
}

const HTMLEditRules*
TextEditRules::AsHTMLEditRules() const
{
  return mIsHTMLEditRules ? static_cast<const HTMLEditRules*>(this) : nullptr;
}

NS_IMPL_CYCLE_COLLECTION(TextEditRules, mBogusNode, mCachedSelectionNode)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(TextEditRules)
  NS_INTERFACE_MAP_ENTRY(nsITimerCallback)
  NS_INTERFACE_MAP_ENTRY(nsINamed)
  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsITimerCallback)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(TextEditRules)
NS_IMPL_CYCLE_COLLECTING_RELEASE(TextEditRules)

nsresult
TextEditRules::Init(TextEditor* aTextEditor)
{
  if (NS_WARN_IF(!aTextEditor)) {
    return NS_ERROR_INVALID_ARG;
  }

  Selection* selection = aTextEditor->GetSelection();
  if (NS_WARN_IF(!selection)) {
    return NS_ERROR_FAILURE;
  }

  InitFields();

  // We hold a non-refcounted reference back to our editor.
  mTextEditor = aTextEditor;
  AutoSafeEditorData setData(*this, *mTextEditor, *selection);

  // Put in a magic <br> if needed. This method handles null selection,
  // which should never happen anyway
  nsresult rv = CreateBogusNodeIfNeeded();
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  // If the selection hasn't been set up yet, set it up collapsed to the end of
  // our editable content.
  if (!SelectionRef().RangeCount()) {
    rv = TextEditorRef().CollapseSelectionToEnd(&SelectionRef());
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  }

  if (IsPlaintextEditor()) {
    // ensure trailing br node
    rv = CreateTrailingBRIfNeeded();
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  }

  // XXX We should use AddBoolVarCache and use "current" value at initializing.
  mDeleteBidiImmediately =
    Preferences::GetBool("bidi.edit.delete_immediately", false);

  return NS_OK;
}

nsresult
TextEditRules::SetInitialValue(const nsAString& aValue)
{
  if (IsPasswordEditor()) {
    mPasswordText = aValue;
  }
  return NS_OK;
}

nsresult
TextEditRules::DetachEditor()
{
  if (mTimer) {
    mTimer->Cancel();
  }
  mTextEditor = nullptr;
  return NS_OK;
}

nsresult
TextEditRules::BeforeEdit(EditSubAction aEditSubAction,
                          nsIEditor::EDirection aDirection)
{
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }

  if (mLockRulesSniffing) {
    return NS_OK;
  }

  AutoLockRulesSniffing lockIt(this);
  mDidExplicitlySetInterline = false;
  if (!mActionNesting) {
    // let rules remember the top level action
    mTopLevelEditSubAction = aEditSubAction;
  }
  mActionNesting++;

  if (aEditSubAction == EditSubAction::eSetText) {
    // setText replaces all text, so mCachedSelectionNode might be invalid on
    // AfterEdit.
    // Since this will be used as start position of spellchecker, we should
    // use root instead.
    mCachedSelectionNode = mTextEditor->GetRoot();
    mCachedSelectionOffset = 0;
  } else {
    Selection* selection = mTextEditor->GetSelection();
    if (NS_WARN_IF(!selection)) {
      return NS_ERROR_FAILURE;
    }
    mCachedSelectionNode = selection->GetAnchorNode();
    mCachedSelectionOffset = selection->AnchorOffset();
  }

  return NS_OK;
}

nsresult
TextEditRules::AfterEdit(EditSubAction aEditSubAction,
                         nsIEditor::EDirection aDirection)
{
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }

  if (mLockRulesSniffing) {
    return NS_OK;
  }

  AutoLockRulesSniffing lockIt(this);

  MOZ_ASSERT(mActionNesting>0, "bad action nesting!");
  if (!--mActionNesting) {
    Selection* selection = mTextEditor->GetSelection();
    if (NS_WARN_IF(!selection)) {
      return NS_ERROR_FAILURE;
    }

    AutoSafeEditorData setData(*this, *mTextEditor, *selection);

    nsresult rv =
      TextEditorRef().HandleInlineSpellCheck(aEditSubAction, *selection,
                                             mCachedSelectionNode,
                                             mCachedSelectionOffset,
                                             nullptr, 0, nullptr, 0);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }

    // no longer uses mCachedSelectionNode, so release it.
    mCachedSelectionNode = nullptr;

    // if only trailing <br> remaining remove it
    rv = RemoveRedundantTrailingBR();
    if (NS_FAILED(rv)) {
      return rv;
    }

    // detect empty doc
    rv = CreateBogusNodeIfNeeded();
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }

    // ensure trailing br node
    rv = CreateTrailingBRIfNeeded();
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }

    // Collapse the selection to the trailing moz-<br> if it's at the end of
    // our text node.
    rv = CollapseSelectionToTrailingBRIfNeeded();
    if (NS_WARN_IF(rv == NS_ERROR_EDITOR_DESTROYED)) {
      return NS_ERROR_EDITOR_DESTROYED;
    }
    NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
      "Failed to selection to after the text node in TextEditor");
  }
  return NS_OK;
}

nsresult
TextEditRules::WillDoAction(Selection* aSelection,
                            EditSubActionInfo& aInfo,
                            bool* aCancel,
                            bool* aHandled)
{
  if (NS_WARN_IF(!aSelection)) {
    return NS_ERROR_INVALID_ARG;
  }
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }

  MOZ_ASSERT(aCancel);
  MOZ_ASSERT(aHandled);

  *aCancel = false;
  *aHandled = false;

  AutoSafeEditorData setData(*this, *mTextEditor, *aSelection);

  // my kingdom for dynamic cast
  switch (aInfo.mEditSubAction) {
    case EditSubAction::eInsertParagraphSeparator:
      UndefineCaretBidiLevel();
      return WillInsertBreak(aCancel, aHandled, aInfo.maxLength);
    case EditSubAction::eInsertText:
    case EditSubAction::eInsertTextComingFromIME:
      UndefineCaretBidiLevel();
      return WillInsertText(aInfo.mEditSubAction, aCancel, aHandled,
                            aInfo.inString, aInfo.outString,
                            aInfo.maxLength);
    case EditSubAction::eSetText:
      UndefineCaretBidiLevel();
      return WillSetText(aCancel, aHandled, aInfo.inString,
                         aInfo.maxLength);
    case EditSubAction::eDeleteSelectedContent:
      return WillDeleteSelection(aInfo.collapsedAction, aCancel, aHandled);
    case EditSubAction::eUndo:
      return WillUndo(aCancel, aHandled);
    case EditSubAction::eRedo:
      return WillRedo(aCancel, aHandled);
    case EditSubAction::eSetTextProperty:
      return WillSetTextProperty(aCancel, aHandled);
    case EditSubAction::eRemoveTextProperty:
      return WillRemoveTextProperty(aCancel, aHandled);
    case EditSubAction::eComputeTextToOutput:
      return WillOutputText(aInfo.outputFormat, aInfo.outString, aInfo.flags,
                            aCancel, aHandled);
    case EditSubAction::eInsertElement:
      // i had thought this would be html rules only.  but we put pre elements
      // into plaintext mail when doing quoting for reply!  doh!
      return WillInsert(aCancel);
    default:
      return NS_ERROR_FAILURE;
  }
}

nsresult
TextEditRules::DidDoAction(Selection* aSelection,
                           EditSubActionInfo& aInfo,
                           nsresult aResult)
{
  if (NS_WARN_IF(!aSelection)) {
    return NS_ERROR_INVALID_ARG;
  }
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }

  AutoSafeEditorData setData(*this, *mTextEditor, *aSelection);

  // don't let any txns in here move the selection around behind our back.
  // Note that this won't prevent explicit selection setting from working.
  AutoTransactionsConserveSelection dontChangeMySelection(TextEditorRef());

  switch (aInfo.mEditSubAction) {
    case EditSubAction::eDeleteSelectedContent:
      return DidDeleteSelection();
    case EditSubAction::eUndo:
      return DidUndo(aResult);
    case EditSubAction::eRedo:
      return DidRedo(aResult);
    default:
      // Don't fail on transactions we don't handle here!
      return NS_OK;
  }
}

bool
TextEditRules::DocumentIsEmpty()
{
  bool retVal = false;
  if (!mTextEditor || NS_FAILED(mTextEditor->IsEmpty(&retVal))) {
    retVal = true;
  }

  return retVal;
}

nsresult
TextEditRules::WillInsert(bool* aCancel)
{
  MOZ_ASSERT(IsEditorDataAvailable());

  if (IsReadonly() || IsDisabled()) {
    if (aCancel) {
      *aCancel = true;
    }
    return NS_OK;
  }

  // initialize out param
  if (aCancel) {
    *aCancel = false;
  }

  // check for the magic content node and delete it if it exists
  if (!mBogusNode) {
    return NS_OK;
  }

  DebugOnly<nsresult> rv =
    TextEditorRef().DeleteNodeWithTransaction(*mBogusNode);
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
    "Failed to remove the bogus node");
  mBogusNode = nullptr;
  return NS_OK;
}

nsresult
TextEditRules::WillInsertBreak(bool* aCancel,
                               bool* aHandled,
                               int32_t aMaxLength)
{
  MOZ_ASSERT(IsEditorDataAvailable());
  if (NS_WARN_IF(!aCancel) || NS_WARN_IF(!aHandled)) {
    return NS_ERROR_INVALID_ARG;
  }
  CANCEL_OPERATION_IF_READONLY_OR_DISABLED
  *aHandled = false;
  if (IsSingleLineEditor()) {
    *aCancel = true;
  } else {
    // handle docs with a max length
    // NOTE, this function copies inString into outString for us.
    NS_NAMED_LITERAL_STRING(inString, "\n");
    nsAutoString outString;
    bool didTruncate;
    nsresult rv =
      TruncateInsertionIfNeeded(&inString.AsString(),
                                &outString, aMaxLength, &didTruncate);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
    if (didTruncate) {
      *aCancel = true;
      return NS_OK;
    }

    *aCancel = false;

    // if the selection isn't collapsed, delete it.
    if (!SelectionRef().IsCollapsed()) {
      rv = TextEditorRef().DeleteSelectionAsSubAction(nsIEditor::eNone,
                                                      nsIEditor::eStrip);
      if (NS_WARN_IF(!CanHandleEditAction())) {
        return NS_ERROR_EDITOR_DESTROYED;
      }
      if (NS_WARN_IF(NS_FAILED(rv))) {
        return rv;
      }
    }

    rv = WillInsert();
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  }
  return NS_OK;
}

nsresult
TextEditRules::CollapseSelectionToTrailingBRIfNeeded()
{
  MOZ_ASSERT(IsEditorDataAvailable());

  // we only need to execute the stuff below if we are a plaintext editor.
  // html editors have a different mechanism for putting in mozBR's
  // (because there are a bunch more places you have to worry about it in html)
  if (!IsPlaintextEditor()) {
    return NS_OK;
  }

  // If there is no selection ranges, we should set to the end of the editor.
  // This is usually performed in TextEditRules::Init(), however, if the
  // editor is reframed, this may be called by AfterEdit().
  if (!SelectionRef().RangeCount()) {
    TextEditorRef().CollapseSelectionToEnd(&SelectionRef());
    if (NS_WARN_IF(!CanHandleEditAction())) {
      return NS_ERROR_EDITOR_DESTROYED;
    }
  }

  // If we are at the end of the <textarea> element, we need to set the
  // selection to stick to the moz-<br> at the end of the <textarea>.
  EditorRawDOMPoint selectionStartPoint(
                      EditorBase::GetStartPoint(&SelectionRef()));
  if (NS_WARN_IF(!selectionStartPoint.IsSet())) {
    return NS_ERROR_FAILURE;
  }

  // Nothing to do if we're not at the end of the text node.
  if (!selectionStartPoint.IsInTextNode() ||
      !selectionStartPoint.IsEndOfContainer()) {
    return NS_OK;
  }

  Element* rootElement = TextEditorRef().GetRoot();
  if (NS_WARN_IF(!rootElement)) {
    return NS_ERROR_NULL_POINTER;
  }
  nsINode* parentNode = selectionStartPoint.GetContainer()->GetParentNode();
  if (parentNode != rootElement) {
    return NS_OK;
  }

  nsINode* nextNode = selectionStartPoint.GetContainer()->GetNextSibling();
  if (!nextNode || !TextEditUtils::IsMozBR(nextNode)) {
    return NS_OK;
  }

  EditorRawDOMPoint afterStartContainer(selectionStartPoint.GetContainer());
  if (NS_WARN_IF(!afterStartContainer.AdvanceOffset())) {
    return NS_ERROR_FAILURE;
  }
  ErrorResult error;
  SelectionRef().Collapse(afterStartContainer, error);
  if (NS_WARN_IF(!CanHandleEditAction())) {
    error.SuppressException();
    return NS_ERROR_EDITOR_DESTROYED;
  }
  if (NS_WARN_IF(error.Failed())) {
    return error.StealNSResult();
  }
  return NS_OK;
}

already_AddRefed<nsINode>
TextEditRules::GetTextNodeAroundSelectionStartContainer()
{
  MOZ_ASSERT(IsEditorDataAvailable());

  EditorRawDOMPoint selectionStartPoint(
                      EditorBase::GetStartPoint(&SelectionRef()));
  if (NS_WARN_IF(!selectionStartPoint.IsSet())) {
    return nullptr;
  }
  if (selectionStartPoint.IsInTextNode()) {
    nsCOMPtr<nsINode> node = selectionStartPoint.GetContainer();
    return node.forget();
  }
  // This should be the root node, walk the tree looking for text nodes.
  // XXX NodeIterator sets mutation observer even for this temporary use.
  //     It's too expensive if this is called from a hot path.
  nsCOMPtr<nsINode> node = selectionStartPoint.GetContainer();
  RefPtr<NodeIterator> iter =
    new NodeIterator(node, NodeFilter_Binding::SHOW_TEXT, nullptr);
  while (!EditorBase::IsTextNode(node)) {
    node = iter->NextNode(IgnoreErrors());
    if (!node) {
      return nullptr;
    }
  }
  return node.forget();
}

#ifdef DEBUG
#define ASSERT_PASSWORD_LENGTHS_EQUAL()                                \
  if (IsPasswordEditor() && mTextEditor->GetRoot()) {                  \
    int32_t txtLen;                                                    \
    mTextEditor->GetTextLength(&txtLen);                               \
    NS_ASSERTION(mPasswordText.Length() == uint32_t(txtLen),           \
                 "password length not equal to number of asterisks");  \
  }
#else
#define ASSERT_PASSWORD_LENGTHS_EQUAL()
#endif

void
TextEditRules::HandleNewLines(nsString& aString)
{
  static const char16_t kLF = static_cast<char16_t>('\n');
  MOZ_ASSERT(IsEditorDataAvailable());
  MOZ_ASSERT(aString.FindChar(static_cast<uint16_t>('\r')) == kNotFound);

  // First of all, check if aString contains '\n' since if the string
  // does not include it, we don't need to do nothing here.
  int32_t firstLF = aString.FindChar(kLF, 0);
  if (firstLF == kNotFound) {
    return;
  }

  switch(TextEditorRef().mNewlineHandling) {
    case nsIPlaintextEditor::eNewlinesReplaceWithSpaces:
      // Default of Firefox:
      // Strip trailing newlines first so we don't wind up with trailing spaces
      aString.Trim(LFSTR, false, true);
      aString.ReplaceChar(kLF, ' ');
      break;
    case nsIPlaintextEditor::eNewlinesStrip:
      aString.StripChar(kLF);
      break;
    case nsIPlaintextEditor::eNewlinesPasteToFirst:
    default: {
      // we get first *non-empty* line.
      int32_t offset = 0;
      while (firstLF == offset) {
        offset++;
        firstLF = aString.FindChar(kLF, offset);
      }
      if (firstLF > 0) {
        aString.Truncate(firstLF);
      }
      if (offset > 0) {
        aString.Cut(0, offset);
      }
      break;
    }
    case nsIPlaintextEditor::eNewlinesReplaceWithCommas:
      // Default of Thunderbird:
      aString.Trim(LFSTR, true, true);
      aString.ReplaceChar(kLF, ',');
      break;
    case nsIPlaintextEditor::eNewlinesStripSurroundingWhitespace: {
      nsAutoString result;
      uint32_t offset = 0;
      while (offset < aString.Length()) {
        int32_t nextLF =
          !offset ? firstLF : aString.FindChar(kLF, offset);
        if (nextLF < 0) {
          result.Append(nsDependentSubstring(aString, offset));
          break;
        }
        uint32_t wsBegin = nextLF;
        // look backwards for the first non-whitespace char
        while (wsBegin > offset && NS_IS_SPACE(aString[wsBegin - 1])) {
          --wsBegin;
        }
        result.Append(nsDependentSubstring(aString, offset, wsBegin - offset));
        offset = nextLF + 1;
        while (offset < aString.Length() && NS_IS_SPACE(aString[offset])) {
          ++offset;
        }
      }
      aString = result;
      break;
    }
    case nsIPlaintextEditor::eNewlinesPasteIntact:
      // even if we're pasting newlines, don't paste leading/trailing ones
      aString.Trim(LFSTR, true, true);
      break;
  }
}

nsresult
TextEditRules::WillInsertText(EditSubAction aEditSubAction,
                              bool* aCancel,
                              bool* aHandled,
                              const nsAString* inString,
                              nsAString* outString,
                              int32_t aMaxLength)
{
  MOZ_ASSERT(IsEditorDataAvailable());

  if (NS_WARN_IF(!aCancel) || NS_WARN_IF(!aHandled)) {
    return NS_ERROR_INVALID_ARG;
  }

  if (inString->IsEmpty() &&
      aEditSubAction != EditSubAction::eInsertTextComingFromIME) {
    // HACK: this is a fix for bug 19395
    // I can't outlaw all empty insertions
    // because IME transaction depend on them
    // There is more work to do to make the
    // world safe for IME.
    *aCancel = true;
    *aHandled = false;
    return NS_OK;
  }

  // initialize out param
  *aCancel = false;
  *aHandled = true;

  // handle docs with a max length
  // NOTE, this function copies inString into outString for us.
  bool truncated = false;
  nsresult rv =
    TruncateInsertionIfNeeded(inString, outString, aMaxLength, &truncated);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }
  // If we're exceeding the maxlength when composing IME, we need to clean up
  // the composing text, so we shouldn't return early.
  if (truncated && outString->IsEmpty() &&
      aEditSubAction != EditSubAction::eInsertTextComingFromIME) {
    *aCancel = true;
    return NS_OK;
  }

  uint32_t start = 0;
  uint32_t end = 0;

  // handle password field docs
  if (IsPasswordEditor()) {
    nsContentUtils::GetSelectionInTextControl(&SelectionRef(),
                                              TextEditorRef().GetRoot(),
                                              start, end);
  }

  // if the selection isn't collapsed, delete it.
  if (!SelectionRef().IsCollapsed()) {
    rv = TextEditorRef().DeleteSelectionAsSubAction(nsIEditor::eNone,
                                                    nsIEditor::eStrip);
    if (NS_WARN_IF(!CanHandleEditAction())) {
      return NS_ERROR_EDITOR_DESTROYED;
    }
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  }

  rv = WillInsert(aCancel);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  // handle password field data
  // this has the side effect of changing all the characters in aOutString
  // to the replacement character
  if (IsPasswordEditor() &&
      aEditSubAction == EditSubAction::eInsertTextComingFromIME) {
    RemoveIMETextFromPWBuf(start, outString);
  }

  // People have lots of different ideas about what text fields
  // should do with multiline pastes.  See bugs 21032, 23485, 23485, 50935.
  // The six possible options are:
  // 0. paste newlines intact
  // 1. paste up to the first newline (default)
  // 2. replace newlines with spaces
  // 3. strip newlines
  // 4. replace with commas
  // 5. strip newlines and surrounding whitespace
  // So find out what we're expected to do:
  if (IsSingleLineEditor()) {
    nsAutoString tString(*outString);
    // XXX Some callers of TextEditor::InsertTextAsAction()  already make the
    //     string use only \n as a linebreaker.  However, they are not hot
    //     path and nsContentUtils::PlatformToDOMLineBreaks() does nothing
    //     if the string doesn't include \r.  So, let's convert linebreakers
    //     here.  Note that there are too many callers of
    //     TextEditor::InsertTextAsAction().  So, it's difficult to keep
    //     maintaining all of them won't reach here without \r nor \r\n.
    nsContentUtils::PlatformToDOMLineBreaks(tString);
    HandleNewLines(tString);
    outString->Assign(tString);
  }

  if (IsPasswordEditor()) {
    // manage the password buffer
    mPasswordText.Insert(*outString, start);

    if (LookAndFeel::GetEchoPassword() && !DontEchoPassword()) {
      nsresult rv = HideLastPasswordInputInternal();
      mLastStart = start;
      mLastLength = outString->Length();
      if (mTimer) {
        mTimer->Cancel();
      }
      if (NS_WARN_IF(NS_FAILED(rv))) {
        return rv;
      }
      if (!mTimer) {
        mTimer = NS_NewTimer();
      }
      mTimer->InitWithCallback(this, LookAndFeel::GetPasswordMaskDelay(),
                               nsITimer::TYPE_ONE_SHOT);
    } else {
      FillBufWithPWChars(outString, outString->Length());
    }
  }

  // get the (collapsed) selection location
  nsRange* firstRange = SelectionRef().GetRangeAt(0);
  if (NS_WARN_IF(!firstRange)) {
    return NS_ERROR_FAILURE;
  }
  EditorRawDOMPoint atStartOfSelection(firstRange->StartRef());
  if (NS_WARN_IF(!atStartOfSelection.IsSetAndValid())) {
    return NS_ERROR_FAILURE;
  }

  // don't put text in places that can't have it
  if (!atStartOfSelection.IsInTextNode() &&
      !TextEditorRef().CanContainTag(*atStartOfSelection.GetContainer(),
                                     *nsGkAtoms::textTagName)) {
    return NS_ERROR_FAILURE;
  }

  // we need to get the doc
  nsCOMPtr<nsIDocument> doc = TextEditorRef().GetDocument();
  if (NS_WARN_IF(!doc)) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  if (aEditSubAction == EditSubAction::eInsertTextComingFromIME) {
    // Find better insertion point to insert text.
    EditorRawDOMPoint betterInsertionPoint =
      TextEditorRef().FindBetterInsertionPoint(atStartOfSelection);
    // If there is one or more IME selections, its minimum offset should be
    // the insertion point.
    int32_t IMESelectionOffset =
      TextEditorRef().GetIMESelectionStartOffsetIn(
                        betterInsertionPoint.GetContainer());
    if (IMESelectionOffset >= 0) {
      betterInsertionPoint.Set(betterInsertionPoint.GetContainer(),
                               IMESelectionOffset);
    }
    rv = TextEditorRef().InsertTextWithTransaction(*doc, *outString,
                                                   betterInsertionPoint);
    if (NS_WARN_IF(!CanHandleEditAction())) {
      return NS_ERROR_EDITOR_DESTROYED;
    }
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  } else {
    // aEditSubAction == EditSubAction::eInsertText

    // don't change my selection in subtransactions
    AutoTransactionsConserveSelection dontChangeMySelection(TextEditorRef());

    EditorRawDOMPoint pointAfterStringInserted;
    rv = TextEditorRef().InsertTextWithTransaction(*doc, *outString,
                                                   atStartOfSelection,
                                                   &pointAfterStringInserted);
    if (NS_WARN_IF(!CanHandleEditAction())) {
      return NS_ERROR_EDITOR_DESTROYED;
    }
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }

    if (pointAfterStringInserted.IsSet()) {
      // Make the caret attach to the inserted text, unless this text ends with a LF,
      // in which case make the caret attach to the next line.
      bool endsWithLF =
        !outString->IsEmpty() && outString->Last() == nsCRT::LF;
      IgnoredErrorResult error;
      SelectionRef().SetInterlinePosition(endsWithLF, error);
      NS_WARNING_ASSERTION(!error.Failed(),
        "Failed to set or unset interline position");

      MOZ_ASSERT(!pointAfterStringInserted.GetChild(),
        "After inserting text into a text node, pointAfterStringInserted."
        "GetChild() should be nullptr");
      error = IgnoredErrorResult();
      SelectionRef().Collapse(pointAfterStringInserted, error);
      if (NS_WARN_IF(!CanHandleEditAction())) {
        return NS_ERROR_EDITOR_DESTROYED;
      }
      NS_WARNING_ASSERTION(!error.Failed(),
        "Failed to collapse selection after inserting string");
    }
  }
  ASSERT_PASSWORD_LENGTHS_EQUAL()
  return NS_OK;
}

nsresult
TextEditRules::WillSetText(bool* aCancel,
                           bool* aHandled,
                           const nsAString* aString,
                           int32_t aMaxLength)
{
  MOZ_ASSERT(IsEditorDataAvailable());
  MOZ_ASSERT(aCancel);
  MOZ_ASSERT(aHandled);
  MOZ_ASSERT(aString);
  MOZ_ASSERT(aString->FindChar(static_cast<char16_t>('\r')) == kNotFound);

  CANCEL_OPERATION_IF_READONLY_OR_DISABLED

  *aHandled = false;
  *aCancel = false;

  if (!IsPlaintextEditor() ||
      TextEditorRef().IsIMEComposing() ||
      TextEditorRef().IsUndoRedoEnabled() ||
      aMaxLength != -1) {
    // SetTextImpl only supports plain text editor without IME and
    // when we don't need to make it undoable.
    return NS_OK;
  }

  if (IsPasswordEditor() && LookAndFeel::GetEchoPassword() &&
      !DontEchoPassword()) {
    // Echo password timer will implement on InsertText.
    return NS_OK;
  }

  nsresult rv = WillInsert(aCancel);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  RefPtr<Element> rootElement = TextEditorRef().GetRoot();
  uint32_t count = rootElement->GetChildCount();

  // handles only when there is only one node and it's a text node, or empty.

  if (count > 1) {
    return NS_OK;
  }

  nsAutoString tString(*aString);

  if (IsPasswordEditor()) {
    mPasswordText.Assign(tString);
    FillBufWithPWChars(&tString, tString.Length());
  } else if (IsSingleLineEditor()) {
    HandleNewLines(tString);
  }

  if (!count) {
    if (tString.IsEmpty()) {
      *aHandled = true;
      return NS_OK;
    }
    RefPtr<nsIDocument> doc = TextEditorRef().GetDocument();
    if (NS_WARN_IF(!doc)) {
      return NS_OK;
    }
    RefPtr<nsTextNode> newNode = EditorBase::CreateTextNode(*doc, tString);
    if (NS_WARN_IF(!newNode)) {
      return NS_OK;
    }
    nsresult rv =
      TextEditorRef().InsertNodeWithTransaction(
                        *newNode, EditorRawDOMPoint(rootElement, 0));
    if (NS_WARN_IF(!CanHandleEditAction())) {
      return NS_ERROR_EDITOR_DESTROYED;
    }
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
    *aHandled = true;

    ASSERT_PASSWORD_LENGTHS_EQUAL();

    return NS_OK;
  }

  nsINode* curNode = rootElement->GetFirstChild();
  if (NS_WARN_IF(!EditorBase::IsTextNode(curNode))) {
    return NS_OK;
  }

  // Even if empty text, we don't remove text node and set empty text
  // for performance
  rv = TextEditorRef().SetTextImpl(SelectionRef(), tString,
                                   *curNode->GetAsText());
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  *aHandled = true;

  ASSERT_PASSWORD_LENGTHS_EQUAL();

  return NS_OK;
}

nsresult
TextEditRules::WillSetTextProperty(bool* aCancel,
                                   bool* aHandled)
{
  if (NS_WARN_IF(!aCancel) || NS_WARN_IF(!aHandled)) {
    return NS_ERROR_INVALID_ARG;
  }

  // XXX: should probably return a success value other than NS_OK that means "not allowed"
  if (IsPlaintextEditor()) {
    *aCancel = true;
  }
  return NS_OK;
}

nsresult
TextEditRules::WillRemoveTextProperty(bool* aCancel,
                                      bool* aHandled)
{
  if (NS_WARN_IF(!aCancel) || NS_WARN_IF(!aHandled)) {
    return NS_ERROR_INVALID_ARG;
  }

  // XXX: should probably return a success value other than NS_OK that means "not allowed"
  if (IsPlaintextEditor()) {
    *aCancel = true;
  }
  return NS_OK;
}

nsresult
TextEditRules::WillDeleteSelection(nsIEditor::EDirection aCollapsedAction,
                                   bool* aCancel,
                                   bool* aHandled)
{
  MOZ_ASSERT(IsEditorDataAvailable());

  if (NS_WARN_IF(!aCancel) || NS_WARN_IF(!aHandled)) {
    return NS_ERROR_INVALID_ARG;
  }
  CANCEL_OPERATION_IF_READONLY_OR_DISABLED

  // initialize out param
  *aCancel = false;
  *aHandled = false;

  // if there is only bogus content, cancel the operation
  if (mBogusNode) {
    *aCancel = true;
    return NS_OK;
  }
  nsresult rv =
    DeleteSelectionWithTransaction(aCollapsedAction, aCancel, aHandled);
  // DeleteSelectionWithTransaction() creates SelectionBatcher.  Therefore,
  // quitting from it might cause having destroyed the editor.
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }
  return NS_OK;
}

nsresult
TextEditRules::DeleteSelectionWithTransaction(
                 nsIEditor::EDirection aCollapsedAction,
                 bool* aCancel,
                 bool* aHandled)
{
  MOZ_ASSERT(IsEditorDataAvailable());
  MOZ_ASSERT(aCancel);
  MOZ_ASSERT(aHandled);

  // If the current selection is empty (e.g the user presses backspace with
  // a collapsed selection), then we want to avoid sending the selectstart
  // event to the user, so we hide selection changes. However, we still
  // want to send a single selectionchange event to the document, so we
  // batch the selectionchange events, such that a single event fires after
  // the AutoHideSelectionChanges destructor has been run.
  SelectionBatcher selectionBatcher(&SelectionRef());
  AutoHideSelectionChanges hideSelection(&SelectionRef());
  nsAutoScriptBlocker scriptBlocker;

  if (IsPasswordEditor()) {
    nsresult rv =
      TextEditorRef().ExtendSelectionForDelete(&SelectionRef(),
                                               &aCollapsedAction);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }

    // manage the password buffer
    uint32_t start, end;
    nsContentUtils::GetSelectionInTextControl(&SelectionRef(),
                                              TextEditorRef().GetRoot(),
                                              start, end);

    if (LookAndFeel::GetEchoPassword()) {
      rv = HideLastPasswordInputInternal();
      mLastStart = start;
      mLastLength = 0;
      if (mTimer) {
        mTimer->Cancel();
      }
      if (NS_WARN_IF(NS_FAILED(rv))) {
        return rv;
      }
    }

    // Collapsed selection.
    if (end == start) {
      // Deleting back.
      if (nsIEditor::ePrevious == aCollapsedAction && start > 0) {
        mPasswordText.Cut(start-1, 1);
      }
      // Deleting forward.
      else if (nsIEditor::eNext == aCollapsedAction) {
        mPasswordText.Cut(start, 1);
      }
      // Otherwise nothing to do for this collapsed selection.
    }
    // Extended selection.
    else {
      mPasswordText.Cut(start, end-start);
    }
  } else {
    EditorRawDOMPoint selectionStartPoint(
                        EditorBase::GetStartPoint(&SelectionRef()));
    if (NS_WARN_IF(!selectionStartPoint.IsSet())) {
      return NS_ERROR_FAILURE;
    }

    if (!SelectionRef().IsCollapsed()) {
      return NS_OK;
    }

    // Test for distance between caret and text that will be deleted
    nsresult rv =
      CheckBidiLevelForDeletion(selectionStartPoint, aCollapsedAction, aCancel);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
    if (*aCancel) {
      return NS_OK;
    }

    rv = TextEditorRef().ExtendSelectionForDelete(&SelectionRef(),
                                                  &aCollapsedAction);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  }

  nsresult rv =
    TextEditorRef().DeleteSelectionWithTransaction(aCollapsedAction,
                                                   nsIEditor::eStrip);
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  *aHandled = true;
  ASSERT_PASSWORD_LENGTHS_EQUAL()
  return NS_OK;
}

nsresult
TextEditRules::DidDeleteSelection()
{
  MOZ_ASSERT(IsEditorDataAvailable());

  EditorRawDOMPoint selectionStartPoint(
                      EditorBase::GetStartPoint(&SelectionRef()));
  if (NS_WARN_IF(!selectionStartPoint.IsSet())) {
    return NS_ERROR_FAILURE;
  }

  // Delete empty text nodes at selection.
  if (selectionStartPoint.IsInTextNode() &&
      !selectionStartPoint.GetContainer()->Length()) {
    nsresult rv =
      TextEditorRef().DeleteNodeWithTransaction(
                        *selectionStartPoint.GetContainer());
    if (NS_WARN_IF(!CanHandleEditAction())) {
      return NS_ERROR_EDITOR_DESTROYED;
    }
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  }

  if (mDidExplicitlySetInterline) {
    return NS_OK;
  }
  // We prevent the caret from sticking on the left of prior BR
  // (i.e. the end of previous line) after this deletion.  Bug 92124
  ErrorResult err;
  SelectionRef().SetInterlinePosition(true, err);
  NS_WARNING_ASSERTION(!err.Failed(), "Failed to set interline position");
  return err.StealNSResult();
}

nsresult
TextEditRules::WillUndo(bool* aCancel,
                        bool* aHandled)
{
  if (NS_WARN_IF(!aCancel) || NS_WARN_IF(!aHandled)) {
    return NS_ERROR_INVALID_ARG;
  }
  CANCEL_OPERATION_IF_READONLY_OR_DISABLED
  // initialize out param
  *aCancel = false;
  *aHandled = false;
  return NS_OK;
}

nsresult
TextEditRules::DidUndo(nsresult aResult)
{
  MOZ_ASSERT(IsEditorDataAvailable());

  // If aResult is an error, we return it.
  if (NS_WARN_IF(NS_FAILED(aResult))) {
    return aResult;
  }

  Element* rootElement = TextEditorRef().GetRoot();
  if (NS_WARN_IF(!rootElement)) {
    return NS_ERROR_FAILURE;
  }

  // The idea here is to see if the magic empty node has suddenly reappeared as
  // the result of the undo.  If it has, set our state so we remember it.
  // There is a tradeoff between doing here and at redo, or doing it everywhere
  // else that might care.  Since undo and redo are relatively rare, it makes
  // sense to take the (small) performance hit here.
  nsIContent* node = TextEditorRef().GetLeftmostChild(rootElement);
  if (node && TextEditorRef().IsMozEditorBogusNode(node)) {
    mBogusNode = node;
  } else {
    mBogusNode = nullptr;
  }
  return aResult;
}

nsresult
TextEditRules::WillRedo(bool* aCancel,
                        bool* aHandled)
{
  if (NS_WARN_IF(!aCancel) || NS_WARN_IF(!aHandled)) {
    return NS_ERROR_INVALID_ARG;
  }
  CANCEL_OPERATION_IF_READONLY_OR_DISABLED
  // initialize out param
  *aCancel = false;
  *aHandled = false;
  return NS_OK;
}

nsresult
TextEditRules::DidRedo(nsresult aResult)
{
  MOZ_ASSERT(IsEditorDataAvailable());

  if (NS_FAILED(aResult)) {
    return aResult; // if aResult is an error, we return it.
  }

  Element* rootElement = TextEditorRef().GetRoot();
  if (NS_WARN_IF(!rootElement)) {
    return NS_ERROR_FAILURE;
  }

  nsCOMPtr<nsIHTMLCollection> nodeList =
    rootElement->GetElementsByTagName(NS_LITERAL_STRING("br"));
  MOZ_ASSERT(nodeList);
  uint32_t len = nodeList->Length();

  if (len != 1) {
    // only in the case of one br could there be the bogus node
    mBogusNode = nullptr;
    return NS_OK;
  }

  Element* brElement = nodeList->Item(0);
  if (TextEditorRef().IsMozEditorBogusNode(brElement)) {
    mBogusNode = brElement;
  } else {
    mBogusNode = nullptr;
  }
  return NS_OK;
}

nsresult
TextEditRules::WillOutputText(const nsAString* aOutputFormat,
                              nsAString* aOutString,
                              uint32_t aFlags,
                              bool* aCancel,
                              bool* aHandled)
{
  MOZ_ASSERT(IsEditorDataAvailable());

  // null selection ok
  if (NS_WARN_IF(!aOutString) || NS_WARN_IF(!aOutputFormat) ||
      NS_WARN_IF(!aCancel) || NS_WARN_IF(!aHandled)) {
    return NS_ERROR_NULL_POINTER;
  }

  // initialize out param
  *aCancel = false;
  *aHandled = false;

  if (!aOutputFormat->LowerCaseEqualsLiteral("text/plain")) {
    return NS_OK;
  }

  // XXX Looks like that even if it's password field, we need to use the
  //     expensive path if the caller requests some complicated handling.
  //     However, changing the behavior for password field might cause
  //     security issue.  So, be careful when you touch here.
  if (IsPasswordEditor()) {
    *aOutString = mPasswordText;
    *aHandled = true;
    return NS_OK;
  }

  // If there is a bogus node, there's no content.  So output empty string.
  if (mBogusNode) {
    aOutString->Truncate();
    *aHandled = true;
    return NS_OK;
  }

  // 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 plain text simply?
  if (aFlags & nsIDocumentEncoder::OutputSelectionOnly ||
      aFlags & nsIDocumentEncoder::OutputWrap) {
    return NS_OK;
  }

  // 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 (TextEditorRef().AsHTMLEditor()) {
    return NS_OK;
  }

  Element* root = TextEditorRef().GetRoot();
  if (!root) { // Don't warn it, this is possible, e.g., 997805.html
    aOutString->Truncate();
    *aHandled = true;
    return NS_OK;
  }

  nsIContent* firstChild = root->GetFirstChild();
  if (!firstChild) {
    aOutString->Truncate();
    *aHandled = true;
    return NS_OK;
  }

  // If it's an <input type="text"> element, the DOM tree should be:
  // <div class="anonymous-div">
  //   #text
  // </div>
  //
  // If it's a <textarea> element, the DOM tree should be:
  // <div class="anonymous-div">
  //   #text (if there is)
  //   <br type="_moz">
  //   <scrollbar orient="horizontal">
  //   ...
  // </div>

  Text* text = firstChild->GetAsText();
  nsIContent* firstChildExceptText =
    text ? firstChild->GetNextSibling() : firstChild;
  // If the DOM tree is unexpected, fall back to the expensive path.
  bool isInput = IsSingleLineEditor();
  bool isTextarea = !isInput;
  if (NS_WARN_IF(isInput && firstChildExceptText) ||
      NS_WARN_IF(isTextarea && !firstChildExceptText) ||
      NS_WARN_IF(isTextarea &&
                 !TextEditUtils::IsMozBR(firstChildExceptText) &&
                 !firstChildExceptText->IsXULElement(nsGkAtoms::scrollbar))) {
    return NS_OK;
  }

  // If there is no text node in the expected DOM tree, we can say that it's
  // just empty.
  if (!text) {
    aOutString->Truncate();
    *aHandled = true;
    return NS_OK;
  }

  // Otherwise, the text is the value.
  text->GetData(*aOutString);

  *aHandled = true;
  return NS_OK;
}

nsresult
TextEditRules::RemoveRedundantTrailingBR()
{
  MOZ_ASSERT(IsEditorDataAvailable());

  // If the bogus node exists, we have no work to do
  if (mBogusNode) {
    return NS_OK;
  }

  // Likewise, nothing to be done if we could never have inserted a trailing br
  if (IsSingleLineEditor()) {
    return NS_OK;
  }

  Element* rootElement = TextEditorRef().GetRoot();
  if (NS_WARN_IF(!rootElement)) {
    return NS_ERROR_NULL_POINTER;
  }

  uint32_t childCount = rootElement->GetChildCount();
  if (childCount > 1) {
    // The trailing br is redundant if it is the only remaining child node
    return NS_OK;
  }

  RefPtr<nsIContent> child = rootElement->GetFirstChild();
  if (!child || !child->IsElement()) {
    return NS_OK;
  }

  RefPtr<Element> childElement = child->AsElement();
  if (!TextEditUtils::IsMozBR(childElement)) {
    return NS_OK;
  }

  // Rather than deleting this node from the DOM tree we should instead
  // morph this br into the bogus node
  childElement->UnsetAttr(kNameSpaceID_None, nsGkAtoms::type, true);
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }

  // set mBogusNode to be this <br>
  mBogusNode = childElement;

  // give it the bogus node attribute
  childElement->SetAttr(kNameSpaceID_None, kMOZEditorBogusNodeAttrAtom,
                        kMOZEditorBogusNodeValue, false);
  return NS_OK;
}

nsresult
TextEditRules::CreateTrailingBRIfNeeded()
{
  MOZ_ASSERT(IsEditorDataAvailable());

  // but only if we aren't a single line edit field
  if (IsSingleLineEditor()) {
    return NS_OK;
  }

  Element* rootElement = TextEditorRef().GetRoot();
  if (NS_WARN_IF(!rootElement)) {
    return NS_ERROR_FAILURE;
  }

  nsCOMPtr<nsIContent> lastChild = rootElement->GetLastChild();
  // assuming CreateBogusNodeIfNeeded() has been called first
  if (NS_WARN_IF(!lastChild)) {
    return NS_ERROR_FAILURE;
  }

  if (!lastChild->IsHTMLElement(nsGkAtoms::br)) {
    AutoTransactionsConserveSelection dontChangeMySelection(TextEditorRef());
    EditorRawDOMPoint endOfRoot;
    endOfRoot.SetToEndOf(rootElement);
    CreateElementResult createMozBrResult = CreateMozBR(endOfRoot);
    if (NS_WARN_IF(createMozBrResult.Failed())) {
      return createMozBrResult.Rv();
    }
    return NS_OK;
  }

  // Check to see if the trailing BR is a former bogus node - this will have
  // stuck around if we previously morphed a trailing node into a bogus node.
  if (!TextEditorRef().IsMozEditorBogusNode(lastChild)) {
    return NS_OK;
  }

  // Morph it back to a mozBR
  lastChild->AsElement()->UnsetAttr(kNameSpaceID_None,
                                    kMOZEditorBogusNodeAttrAtom,
                                    false);
  lastChild->AsElement()->SetAttr(kNameSpaceID_None, nsGkAtoms::type,
                                  NS_LITERAL_STRING("_moz"),
                                  true);
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }
  return NS_OK;
}

nsresult
TextEditRules::CreateBogusNodeIfNeeded()
{
  MOZ_ASSERT(IsEditorDataAvailable());

  if (mBogusNode) {
    // Let's not create more than one, ok?
    return NS_OK;
  }

  // tell rules system to not do any post-processing
  AutoTopLevelEditSubActionNotifier maybeTopLevelEditSubAction(
                                      TextEditorRef(),
                                      EditSubAction::eCreateBogusNode,
                                      nsIEditor::eNone);

  RefPtr<Element> rootElement = TextEditorRef().GetRoot();
  if (!rootElement) {
    // We don't even have a body yet, don't insert any bogus nodes at
    // this point.
    return NS_OK;
  }

  // Now we've got the body element. Iterate over the body element's children,
  // looking for editable content. If no editable content is found, insert the
  // bogus node.
  bool isRootEditable = TextEditorRef().IsEditable(rootElement);
  for (nsIContent* rootChild = rootElement->GetFirstChild();
       rootChild;
       rootChild = rootChild->GetNextSibling()) {
    if (TextEditorRef().IsMozEditorBogusNode(rootChild) ||
        !isRootEditable ||
        TextEditorRef().IsEditable(rootChild) ||
        TextEditorRef().IsBlockNode(rootChild)) {
      return NS_OK;
    }
  }

  // Skip adding the bogus node if body is read-only.
  if (!TextEditorRef().IsModifiableNode(*rootElement)) {
    return NS_OK;
  }

  // Create a br.
  RefPtr<Element> newBrElement =
    TextEditorRef().CreateHTMLContent(nsGkAtoms::br);
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }
  if (NS_WARN_IF(!newBrElement)) {
    return NS_ERROR_FAILURE;
  }

  // set mBogusNode to be the newly created <br>
  mBogusNode = newBrElement;

  // Give it a special attribute.
  newBrElement->SetAttr(kNameSpaceID_None, kMOZEditorBogusNodeAttrAtom,
                        kMOZEditorBogusNodeValue, false);

  // Put the node in the document.
  nsresult rv =
    TextEditorRef().InsertNodeWithTransaction(
                      *mBogusNode, EditorRawDOMPoint(rootElement, 0));
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  // Set selection.
  IgnoredErrorResult error;
  SelectionRef().Collapse(EditorRawDOMPoint(rootElement, 0), error);
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }
  NS_WARNING_ASSERTION(!error.Failed(),
    "Failed to collapse selection at start of the root element");
  return NS_OK;
}


nsresult
TextEditRules::TruncateInsertionIfNeeded(const nsAString* aInString,
                                         nsAString* aOutString,
                                         int32_t aMaxLength,
                                         bool* aTruncated)
{
  MOZ_ASSERT(IsEditorDataAvailable());

  if (NS_WARN_IF(!aInString) || NS_WARN_IF(!aOutString)) {
    return NS_ERROR_INVALID_ARG;
  }

  if (!aOutString->Assign(*aInString, mozilla::fallible)) {
    return NS_ERROR_OUT_OF_MEMORY;
  }
  if (aTruncated) {
    *aTruncated = false;
  }

  if (-1 != aMaxLength && IsPlaintextEditor() &&
      !TextEditorRef().IsIMEComposing()) {
    // Get the current text length.
    // Get the length of inString.
    // Get the length of the selection.
    //   If selection is collapsed, it is length 0.
    //   Subtract the length of the selection from the len(doc)
    //   since we'll delete the selection on insert.
    //   This is resultingDocLength.
    // Get old length of IME composing string
    //   which will be replaced by new one.
    // If (resultingDocLength) is at or over max, cancel the insert
    // If (resultingDocLength) + (length of input) > max,
    //    set aOutString to subset of inString so length = max
    int32_t docLength;
    nsresult rv = TextEditorRef().GetTextLength(&docLength);
    if (NS_FAILED(rv)) {
      return rv;
    }

    uint32_t start, end;
    nsContentUtils::GetSelectionInTextControl(&SelectionRef(),
                                              TextEditorRef().GetRoot(),
                                              start, end);

    TextComposition* composition = TextEditorRef().GetComposition();
    uint32_t oldCompStrLength = composition ? composition->String().Length() : 0;

    const uint32_t selectionLength = end - start;
    const int32_t resultingDocLength = docLength - selectionLength - oldCompStrLength;
    if (resultingDocLength >= aMaxLength) {
      // This call is guaranteed to reduce the capacity of the string, so it
      // cannot cause an OOM.
      aOutString->Truncate();
      if (aTruncated) {
        *aTruncated = true;
      }
    } else {
      int32_t oldLength = aOutString->Length();
      if (oldLength + resultingDocLength > aMaxLength) {
        int32_t newLength = aMaxLength - resultingDocLength;
        MOZ_ASSERT(newLength > 0);
        char16_t newLastChar = aOutString->CharAt(newLength - 1);
        char16_t removingFirstChar = aOutString->CharAt(newLength);
        // Don't separate the string between a surrogate pair.
        if (NS_IS_HIGH_SURROGATE(newLastChar) &&
            NS_IS_LOW_SURROGATE(removingFirstChar)) {
          newLength--;
        }
        // XXX What should we do if we're removing IVS and its preceding
        //     character won't be removed?
        // This call is guaranteed to reduce the capacity of the string, so it
        // cannot cause an OOM.
        aOutString->Truncate(newLength);
        if (aTruncated) {
          *aTruncated = true;
        }
      }
    }
  }
  return NS_OK;
}

void
TextEditRules::ResetIMETextPWBuf()
{
  mPasswordIMEText.Truncate();
}

void
TextEditRules::RemoveIMETextFromPWBuf(uint32_t& aStart,
                                      nsAString* aIMEString)
{
  MOZ_ASSERT(aIMEString);

  // initialize PasswordIME
  if (mPasswordIMEText.IsEmpty()) {
    mPasswordIMEIndex = aStart;
  } else {
    // manage the password buffer
    mPasswordText.Cut(mPasswordIMEIndex, mPasswordIMEText.Length());
    aStart = mPasswordIMEIndex;
  }

  mPasswordIMEText.Assign(*aIMEString);
}

NS_IMETHODIMP
TextEditRules::Notify(nsITimer* aTimer)
{
  MOZ_ASSERT(mTimer);

  if (NS_WARN_IF(!mTextEditor)) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  // Check whether our text editor's password flag was changed before this
  // "hide password character" timer actually fires.
  if (!IsPasswordEditor()) {
    return NS_OK;
  }

  RefPtr<TextEditor> textEditor(mTextEditor);
  nsresult rv = textEditor->HideLastPasswordInput();
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }
  return NS_OK;
}

nsresult
TextEditRules::HideLastPasswordInput(Selection& aSelection)
{
  MOZ_ASSERT(IsPasswordEditor());

  AutoSafeEditorData setData(*this, *mTextEditor, aSelection);

  // Check whether our text editor's password flag was changed before this
  // "hide password character" timer actually fires.
  nsresult rv = HideLastPasswordInputInternal();
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }
  ASSERT_PASSWORD_LENGTHS_EQUAL();
  mLastLength = 0;
  return NS_OK;
}

NS_IMETHODIMP
TextEditRules::GetName(nsACString& aName)
{
  aName.AssignLiteral("TextEditRules");
  return NS_OK;
}

nsresult
TextEditRules::HideLastPasswordInputInternal()
{
  MOZ_ASSERT(IsEditorDataAvailable());

  if (!mLastLength) {
    // Special case, we're trying to replace a range that no longer exists
    return NS_OK;
  }

  nsAutoString hiddenText;
  FillBufWithPWChars(&hiddenText, mLastLength);

  uint32_t start, end;
  nsContentUtils::GetSelectionInTextControl(&SelectionRef(),
                                            TextEditorRef().GetRoot(),
                                            start, end);

  nsCOMPtr<nsINode> selNode = GetTextNodeAroundSelectionStartContainer();
  if (NS_WARN_IF(!selNode)) {
    return NS_OK;
  }

  selNode->GetAsText()->ReplaceData(mLastStart, mLastLength, hiddenText,
                                    IgnoreErrors());
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }
  // XXXbz Selection::Collapse/Extend take int32_t, but there are tons of
  // callsites... Converting all that is a battle for another day.
  DebugOnly<nsresult> rv = SelectionRef().Collapse(selNode, start);
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return NS_ERROR_EDITOR_DESTROYED;
  }
  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "Failed to collapse selection");
  if (start != end) {
    rv = SelectionRef().Extend(selNode, end);
    if (NS_WARN_IF(!CanHandleEditAction())) {
      return NS_ERROR_EDITOR_DESTROYED;
    }
    NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "Failed to extend selection");
  }
  return NS_OK;
}

// static
void
TextEditRules::FillBufWithPWChars(nsAString* aOutString,
                                  int32_t aLength)
{
  MOZ_ASSERT(aOutString);

  // change the output to the platform password character
  char16_t passwordChar = LookAndFeel::GetPasswordCharacter();

  aOutString->Truncate();
  for (int32_t i = 0; i < aLength; i++) {
    aOutString->Append(passwordChar);
  }
}

template<typename PT, typename CT>
CreateElementResult
TextEditRules::CreateBRInternal(
                 const EditorDOMPointBase<PT, CT>& aPointToInsert,
                 bool aCreateMozBR)
{
  MOZ_ASSERT(IsEditorDataAvailable());

  if (NS_WARN_IF(!aPointToInsert.IsSet())) {
    return CreateElementResult(NS_ERROR_FAILURE);
  }

  RefPtr<Element> brElement =
    TextEditorRef().InsertBrElementWithTransaction(SelectionRef(),
                                                   aPointToInsert);
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return CreateElementResult(NS_ERROR_EDITOR_DESTROYED);
  }
  if (NS_WARN_IF(!brElement)) {
    return CreateElementResult(NS_ERROR_FAILURE);
  }

  // give it special moz attr
  if (!aCreateMozBR) {
    return CreateElementResult(brElement.forget());
  }

  // XXX Why do we need to set this attribute with transaction?
  nsresult rv =
    TextEditorRef().SetAttributeWithTransaction(*brElement, *nsGkAtoms::type,
                                                NS_LITERAL_STRING("_moz"));
  // XXX Don't we need to remove the new <br> element from the DOM tree
  //     in these case?
  if (NS_WARN_IF(!CanHandleEditAction())) {
    return CreateElementResult(NS_ERROR_EDITOR_DESTROYED);
  }
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return CreateElementResult(NS_ERROR_FAILURE);
  }
  return CreateElementResult(brElement.forget());
}

nsresult
TextEditRules::DocumentModified()
{
  return NS_ERROR_NOT_IMPLEMENTED;
}

bool
TextEditRules::IsPasswordEditor() const
{
  return mTextEditor ? mTextEditor->IsPasswordEditor() : false;
}

bool
TextEditRules::IsSingleLineEditor() const
{
  return mTextEditor ? mTextEditor->IsSingleLineEditor() : false;
}

bool
TextEditRules::IsPlaintextEditor() const
{
  return mTextEditor ? mTextEditor->IsPlaintextEditor() : false;
}

bool
TextEditRules::IsReadonly() const
{
  return mTextEditor ? mTextEditor->IsReadonly() : false;
}

bool
TextEditRules::IsDisabled() const
{
  return mTextEditor ? mTextEditor->IsDisabled() : false;
}
bool
TextEditRules::IsMailEditor() const
{
  return mTextEditor ? mTextEditor->IsMailEditor() : false;
}

bool
TextEditRules::DontEchoPassword() const
{
  return mTextEditor ? mTextEditor->DontEchoPassword() : false;
}

} // namespace mozilla