widget/TextEventDispatcher.cpp
author Masayuki Nakano <masayuki@d-toybox.com>
Fri, 23 Mar 2018 12:06:55 +0900
changeset 413353 2ab582bacc98fecfc3cc52b3f275a23ff40a683f
parent 408848 a0de39bcd31848b43bba37cacaa55552decebd14
child 424533 c0cd065ee5c8832f6962d09805541ecad1d5398e
permissions -rw-r--r--
Bug 1440189 - Stop dispatching keypress event to the default event group in web content (only Nightly and early Beta) unless web page isn't in blacklist r=smaug UI Events declares that keypress event should be fired only when the keydown sequence produces some characters. For conforming to UI Events and compatibility with the other browsers, we should stop dispatching keypress events for non-printable keys. For getting regression reports, we should enable this new behavior only on Nightly. However, some web apps actually broken with the standardized behavior. For protecting testers from known broken web apps, this patch introduces a blacklist to take the traditional behavior under specific domain (and path in it, optionally). Currently, docs.google.com and mail.google.com are set by default. MozReview-Commit-ID: HSrYX8LUB0p

/* -*- 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/Preferences.h"
#include "mozilla/TextEvents.h"
#include "mozilla/TextEventDispatcher.h"
#include "nsIDocShell.h"
#include "nsIFrame.h"
#include "nsIPresShell.h"
#include "nsIWidget.h"
#include "nsPIDOMWindow.h"
#include "nsView.h"
#include "PuppetWidget.h"

namespace mozilla {
namespace widget {

/******************************************************************************
 * TextEventDispatcher
 *****************************************************************************/

bool TextEventDispatcher::sDispatchKeyEventsDuringComposition = false;
bool TextEventDispatcher::sDispatchKeyPressEventsOnlySystemGroupInContent =
       false;

TextEventDispatcher::TextEventDispatcher(nsIWidget* aWidget)
  : mWidget(aWidget)
  , mDispatchingEvent(0)
  , mInputTransactionType(eNoInputTransaction)
  , mIsComposing(false)
  , mIsHandlingComposition(false)
  , mHasFocus(false)
{
  MOZ_RELEASE_ASSERT(mWidget, "aWidget must not be nullptr");

  static bool sInitialized = false;
  if (!sInitialized) {
    Preferences::AddBoolVarCache(
      &sDispatchKeyEventsDuringComposition,
      "dom.keyboardevent.dispatch_during_composition",
      true);
    Preferences::AddBoolVarCache(
      &sDispatchKeyPressEventsOnlySystemGroupInContent,
      "dom.keyboardevent.keypress."
        "dispatch_non_printable_keys_only_system_group_in_content",
      true);
    sInitialized = true;
  }

  ClearNotificationRequests();
}

nsresult
TextEventDispatcher::BeginInputTransaction(
                       TextEventDispatcherListener* aListener)
{
  return BeginInputTransactionInternal(aListener,
                                       eSameProcessSyncInputTransaction);
}

nsresult
TextEventDispatcher::BeginTestInputTransaction(
                       TextEventDispatcherListener* aListener,
                       bool aIsAPZAware)
{
  return BeginInputTransactionInternal(aListener,
           aIsAPZAware ? eAsyncTestInputTransaction :
                         eSameProcessSyncTestInputTransaction);
}

nsresult
TextEventDispatcher::BeginNativeInputTransaction()
{
  if (NS_WARN_IF(!mWidget)) {
    return NS_ERROR_FAILURE;
  }
  RefPtr<TextEventDispatcherListener> listener =
    mWidget->GetNativeTextEventDispatcherListener();
  if (NS_WARN_IF(!listener)) {
    return NS_ERROR_FAILURE;
  }
  return BeginInputTransactionInternal(listener, eNativeInputTransaction);
}

nsresult
TextEventDispatcher::BeginInputTransactionInternal(
                       TextEventDispatcherListener* aListener,
                       InputTransactionType aType)
{
  if (NS_WARN_IF(!aListener)) {
    return NS_ERROR_INVALID_ARG;
  }
  nsCOMPtr<TextEventDispatcherListener> listener = do_QueryReferent(mListener);
  if (listener) {
    if (listener == aListener && mInputTransactionType == aType) {
      UpdateNotificationRequests();
      return NS_OK;
    }
    // If this has composition or is dispatching an event, any other listener
    // can steal ownership.  Especially, if the latter case is allowed,
    // nobody cannot begin input transaction with this if a modal dialog is
    // opened during dispatching an event.
    if (IsComposing() || IsDispatchingEvent()) {
      return NS_ERROR_ALREADY_INITIALIZED;
    }
  }
  mListener = do_GetWeakReference(aListener);
  mInputTransactionType = aType;
  if (listener && listener != aListener) {
    listener->OnRemovedFrom(this);
  }
  UpdateNotificationRequests();
  return NS_OK;
}

nsresult
TextEventDispatcher::BeginInputTransactionFor(const WidgetGUIEvent* aEvent,
                                              PuppetWidget* aPuppetWidget)
{
  MOZ_ASSERT(XRE_IsContentProcess());
  MOZ_ASSERT(!IsDispatchingEvent());

  switch (aEvent->mMessage) {
    case eKeyDown:
    case eKeyPress:
    case eKeyUp:
      MOZ_ASSERT(aEvent->mClass == eKeyboardEventClass);
      break;
    case eCompositionStart:
    case eCompositionChange:
    case eCompositionCommit:
    case eCompositionCommitAsIs:
      MOZ_ASSERT(aEvent->mClass == eCompositionEventClass);
      break;
    default:
      return NS_ERROR_INVALID_ARG;
  }

  if (aEvent->mFlags.mIsSynthesizedForTests) {
    // If the event is for an automated test and this instance dispatched
    // an event to the parent process, we can assume that this is already
    // initialized properly.
    if (mInputTransactionType == eAsyncTestInputTransaction) {
      return NS_OK;
    }
    // Even if the event coming from the parent process is synthesized for
    // tests, this process should treat it as "sync" test here because
    // it won't be go back to the parent process.
    nsresult rv =
      BeginInputTransactionInternal(
        static_cast<TextEventDispatcherListener*>(aPuppetWidget),
        eSameProcessSyncTestInputTransaction);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  } else {
    nsresult rv = BeginNativeInputTransaction();
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  }

  // Emulate modifying members which indicate the state of composition.
  // If we need to manage more states and/or more complexly, we should create
  // internal methods which are called by both here and each event dispatcher
  // method of this class.
  switch (aEvent->mMessage) {
    case eKeyDown:
    case eKeyPress:
    case eKeyUp:
      return NS_OK;
    case eCompositionStart:
      MOZ_ASSERT(!mIsComposing);
      mIsComposing = mIsHandlingComposition = true;
      return NS_OK;
    case eCompositionChange:
      MOZ_ASSERT(mIsComposing);
      MOZ_ASSERT(mIsHandlingComposition);
      mIsComposing = mIsHandlingComposition = true;
      return NS_OK;
    case eCompositionCommit:
    case eCompositionCommitAsIs:
      MOZ_ASSERT(mIsComposing);
      MOZ_ASSERT(mIsHandlingComposition);
      mIsComposing = false;
      mIsHandlingComposition = true;
      return NS_OK;
    default:
      MOZ_ASSERT_UNREACHABLE("You forgot to handle the event");
      return NS_ERROR_UNEXPECTED;
  }
}
void
TextEventDispatcher::EndInputTransaction(TextEventDispatcherListener* aListener)
{
  if (NS_WARN_IF(IsComposing()) || NS_WARN_IF(IsDispatchingEvent())) {
    return;
  }

  mInputTransactionType = eNoInputTransaction;

  nsCOMPtr<TextEventDispatcherListener> listener = do_QueryReferent(mListener);
  if (NS_WARN_IF(!listener)) {
    return;
  }

  if (NS_WARN_IF(listener != aListener)) {
    return;
  }

  mListener = nullptr;
  listener->OnRemovedFrom(this);
  UpdateNotificationRequests();
}

void
TextEventDispatcher::OnDestroyWidget()
{
  mWidget = nullptr;
  mHasFocus = false;
  ClearNotificationRequests();
  mPendingComposition.Clear();
  nsCOMPtr<TextEventDispatcherListener> listener = do_QueryReferent(mListener);
  mListener = nullptr;
  mInputTransactionType = eNoInputTransaction;
  if (listener) {
    listener->OnRemovedFrom(this);
  }
}

nsresult
TextEventDispatcher::GetState() const
{
  nsCOMPtr<TextEventDispatcherListener> listener = do_QueryReferent(mListener);
  if (!listener) {
    return NS_ERROR_NOT_INITIALIZED;
  }
  if (!mWidget || mWidget->Destroyed()) {
    return NS_ERROR_NOT_AVAILABLE;
  }
  return NS_OK;
}

void
TextEventDispatcher::InitEvent(WidgetGUIEvent& aEvent) const
{
  aEvent.mTime = PR_IntervalNow();
  aEvent.mRefPoint = LayoutDeviceIntPoint(0, 0);
  aEvent.mFlags.mIsSynthesizedForTests = IsForTests();
  if (aEvent.mClass != eCompositionEventClass) {
    return;
  }
  void* pseudoIMEContext = GetPseudoIMEContext();
  if (pseudoIMEContext) {
    aEvent.AsCompositionEvent()->mNativeIMEContext.
      InitWithRawNativeIMEContext(pseudoIMEContext);
  }
#ifdef DEBUG
  else {
    MOZ_ASSERT(!XRE_IsContentProcess(),
      "Why did the content process start native event transaction?");
    MOZ_ASSERT(aEvent.AsCompositionEvent()->mNativeIMEContext.IsValid(),
      "Native IME context shouldn't be invalid");
  }
#endif // #ifdef DEBUG
}

nsresult
TextEventDispatcher::DispatchEvent(nsIWidget* aWidget,
                                   WidgetGUIEvent& aEvent,
                                   nsEventStatus& aStatus)
{
  MOZ_ASSERT(!aEvent.AsInputEvent(), "Use DispatchInputEvent()");

  RefPtr<TextEventDispatcher> kungFuDeathGrip(this);
  nsCOMPtr<nsIWidget> widget(aWidget);
  mDispatchingEvent++;
  nsresult rv = widget->DispatchEvent(&aEvent, aStatus);
  mDispatchingEvent--;
  return rv;
}

nsresult
TextEventDispatcher::DispatchInputEvent(nsIWidget* aWidget,
                                        WidgetInputEvent& aEvent,
                                        nsEventStatus& aStatus)
{
  RefPtr<TextEventDispatcher> kungFuDeathGrip(this);
  nsCOMPtr<nsIWidget> widget(aWidget);
  mDispatchingEvent++;

  // If the event is dispatched via nsIWidget::DispatchInputEvent(), it
  // sends the event to the parent process first since APZ needs to handle it
  // first.  However, some callers (e.g., keyboard apps on B2G and tests
  // expecting synchronous dispatch) don't want this to do that.
  nsresult rv = NS_OK;
  if (ShouldSendInputEventToAPZ()) {
    aStatus = widget->DispatchInputEvent(&aEvent);
  } else {
    rv = widget->DispatchEvent(&aEvent, aStatus);
  }

  mDispatchingEvent--;
  return rv;
}

nsresult
TextEventDispatcher::StartComposition(nsEventStatus& aStatus,
                                      const WidgetEventTime* aEventTime)
{
  aStatus = nsEventStatus_eIgnore;

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

  if (NS_WARN_IF(mIsComposing)) {
    return NS_ERROR_FAILURE;
  }

  // When you change some members from here, you may need same change in
  // BeginInputTransactionFor().
  mIsComposing = mIsHandlingComposition = true;
  WidgetCompositionEvent compositionStartEvent(true, eCompositionStart,
                                               mWidget);
  InitEvent(compositionStartEvent);
  if (aEventTime) {
    compositionStartEvent.AssignEventTime(*aEventTime);
  }
  rv = DispatchEvent(mWidget, compositionStartEvent, aStatus);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  return NS_OK;
}

nsresult
TextEventDispatcher::StartCompositionAutomaticallyIfNecessary(
                       nsEventStatus& aStatus,
                       const WidgetEventTime* aEventTime)
{
  if (IsComposing()) {
    return NS_OK;
  }

  nsresult rv = StartComposition(aStatus, aEventTime);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  // If started composition has already been committed, we shouldn't dispatch
  // the compositionchange event.
  if (!IsComposing()) {
    aStatus = nsEventStatus_eConsumeNoDefault;
    return NS_OK;
  }

  // Note that the widget might be destroyed during a call of
  // StartComposition().  In such case, we shouldn't keep dispatching next
  // event.
  rv = GetState();
  if (NS_FAILED(rv)) {
    MOZ_ASSERT(rv != NS_ERROR_NOT_INITIALIZED,
               "aDispatcher must still be initialized in this case");
    aStatus = nsEventStatus_eConsumeNoDefault;
    return NS_OK; // Don't throw exception in this case
  }

  aStatus = nsEventStatus_eIgnore;
  return NS_OK;
}

nsresult
TextEventDispatcher::CommitComposition(nsEventStatus& aStatus,
                                       const nsAString* aCommitString,
                                       const WidgetEventTime* aEventTime)
{
  aStatus = nsEventStatus_eIgnore;

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

  // When there is no composition, caller shouldn't try to commit composition
  // with non-existing composition string nor commit composition with empty
  // string.
  if (NS_WARN_IF(!IsComposing() &&
                 (!aCommitString || aCommitString->IsEmpty()))) {
    return NS_ERROR_FAILURE;
  }

  nsCOMPtr<nsIWidget> widget(mWidget);
  rv = StartCompositionAutomaticallyIfNecessary(aStatus, aEventTime);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }
  if (aStatus == nsEventStatus_eConsumeNoDefault) {
    return NS_OK;
  }

  // When you change some members from here, you may need same change in
  // BeginInputTransactionFor().

  // End current composition and make this free for other IMEs.
  mIsComposing = false;

  EventMessage message = aCommitString ? eCompositionCommit :
                                         eCompositionCommitAsIs;
  WidgetCompositionEvent compositionCommitEvent(true, message, widget);
  InitEvent(compositionCommitEvent);
  if (aEventTime) {
    compositionCommitEvent.AssignEventTime(*aEventTime);
  }
  if (message == eCompositionCommit) {
    compositionCommitEvent.mData = *aCommitString;
    // Don't send CRLF nor CR, replace it with LF here.
    compositionCommitEvent.mData.ReplaceSubstring(NS_LITERAL_STRING("\r\n"),
                                                  NS_LITERAL_STRING("\n"));
    compositionCommitEvent.mData.ReplaceSubstring(NS_LITERAL_STRING("\r"),
                                                  NS_LITERAL_STRING("\n"));
  }
  rv = DispatchEvent(widget, compositionCommitEvent, aStatus);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  return NS_OK;
}

nsresult
TextEventDispatcher::NotifyIME(const IMENotification& aIMENotification)
{
  nsresult rv = NS_ERROR_NOT_IMPLEMENTED;

  switch (aIMENotification.mMessage) {
    case NOTIFY_IME_OF_BLUR:
      mHasFocus = false;
      ClearNotificationRequests();
      break;
    case NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED:
      // If content handles composition events when native IME doesn't have
      // composition, that means that we completely finished handling
      // composition(s).  Note that when focused content is in a remote
      // process, this is sent when all dispatched composition events
      // have been handled in the remote process.
      if (!IsComposing()) {
        mIsHandlingComposition = false;
      }
      break;
    default:
      break;
  }


  // First, send the notification to current input transaction's listener.
  nsCOMPtr<TextEventDispatcherListener> listener = do_QueryReferent(mListener);
  if (listener) {
    rv = listener->NotifyIME(this, aIMENotification);
  }

  if (!mWidget) {
    return rv;
  }

  // If current input transaction isn't for native event handler, we should
  // send the notification to the native text event dispatcher listener
  // since native event handler may need to do something from
  // TextEventDispatcherListener::NotifyIME() even before there is no
  // input transaction yet.  For example, native IME handler may need to
  // create new context at receiving NOTIFY_IME_OF_FOCUS.  In this case,
  // mListener may not be initialized since input transaction should be
  // initialized immediately before dispatching every WidgetKeyboardEvent
  // and WidgetCompositionEvent (dispatching events always occurs after
  // focus move).
  nsCOMPtr<TextEventDispatcherListener> nativeListener =
    mWidget->GetNativeTextEventDispatcherListener();
  if (listener != nativeListener && nativeListener) {
    switch (aIMENotification.mMessage) {
      case REQUEST_TO_COMMIT_COMPOSITION:
      case REQUEST_TO_CANCEL_COMPOSITION:
        // It's not necessary to notify native IME of requests.
        break;
      default: {
        // Even if current input transaction's listener returns NS_OK or
        // something, we need to notify native IME of notifications because
        // when user typing after TIP does something, the changed information
        // is necessary for them.
        nsresult rv2 =
          nativeListener->NotifyIME(this, aIMENotification);
        // But return the result from current listener except when the
        // notification isn't handled.
        if (rv == NS_ERROR_NOT_IMPLEMENTED) {
          rv = rv2;
        }
        break;
      }
    }
  }

  if (aIMENotification.mMessage == NOTIFY_IME_OF_FOCUS) {
    mHasFocus = true;
    UpdateNotificationRequests();
  }

  return rv;
}

void
TextEventDispatcher::ClearNotificationRequests()
{
  mIMENotificationRequests = IMENotificationRequests();
}

void
TextEventDispatcher::UpdateNotificationRequests()
{
  ClearNotificationRequests();

  // If it doesn't has focus, no notifications are available.
  if (!mHasFocus || !mWidget) {
    return;
  }

  // If there is a listener, its requests are necessary.
  nsCOMPtr<TextEventDispatcherListener> listener = do_QueryReferent(mListener);
  if (listener) {
    mIMENotificationRequests = listener->GetIMENotificationRequests();
  }

  // Even if this is in non-native input transaction, native IME needs
  // requests.  So, add native IME requests too.
  if (!IsInNativeInputTransaction()) {
    nsCOMPtr<TextEventDispatcherListener> nativeListener =
      mWidget->GetNativeTextEventDispatcherListener();
    if (nativeListener) {
      mIMENotificationRequests |= nativeListener->GetIMENotificationRequests();
    }
  }
}

bool
TextEventDispatcher::DispatchKeyboardEvent(
                       EventMessage aMessage,
                       const WidgetKeyboardEvent& aKeyboardEvent,
                       nsEventStatus& aStatus,
                       void* aData)
{
  return DispatchKeyboardEventInternal(aMessage, aKeyboardEvent, aStatus,
                                       aData);
}

bool
TextEventDispatcher::DispatchKeyboardEventInternal(
                       EventMessage aMessage,
                       const WidgetKeyboardEvent& aKeyboardEvent,
                       nsEventStatus& aStatus,
                       void* aData,
                       uint32_t aIndexOfKeypress,
                       bool aNeedsCallback)
{
  // Note that this method is also used for dispatching key events on a plugin
  // because key events on a plugin should be dispatched same as normal key
  // events.  Then, only some handlers which need to intercept key events
  // before the focused plugin (e.g., reserved shortcut key handlers) can
  // consume the events.
  MOZ_ASSERT(WidgetKeyboardEvent::IsKeyDownOrKeyDownOnPlugin(aMessage) ||
             WidgetKeyboardEvent::IsKeyUpOrKeyUpOnPlugin(aMessage) ||
             aMessage == eKeyPress, "Invalid aMessage value");
  nsresult rv = GetState();
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return false;
  }

  // If the key shouldn't cause keypress events, don't this patch them.
  if (aMessage == eKeyPress && !aKeyboardEvent.ShouldCauseKeypressEvents()) {
    return false;
  }

  // Basically, key events shouldn't be dispatched during composition.
  // Note that plugin process has different IME context.  Therefore, we don't
  // need to check our composition state when the key event is fired on a
  // plugin.
  if (IsComposing() && !WidgetKeyboardEvent::IsKeyEventOnPlugin(aMessage)) {
    // However, if we need to behave like other browsers, we need the keydown
    // and keyup events.  Note that this behavior is also allowed by D3E spec.
    // FYI: keypress events must not be fired during composition.
    if (!sDispatchKeyEventsDuringComposition || aMessage == eKeyPress) {
      return false;
    }
    // XXX If there was mOnlyContentDispatch for this case, it might be useful
    //     because our chrome doesn't assume that key events are fired during
    //     composition.
  }

  WidgetKeyboardEvent keyEvent(true, aMessage, mWidget);
  InitEvent(keyEvent);
  keyEvent.AssignKeyEventData(aKeyboardEvent, false);

  if (aStatus == nsEventStatus_eConsumeNoDefault) {
    // If the key event should be dispatched as consumed event, marking it here.
    // This is useful to prevent double action.  E.g., when the key was already
    // handled by system, our chrome shouldn't handle it.
    keyEvent.PreventDefaultBeforeDispatch();
  }

  // Corrects each member for the specific key event type.
  if (keyEvent.mKeyNameIndex != KEY_NAME_INDEX_USE_STRING) {
    MOZ_ASSERT(!aIndexOfKeypress,
      "aIndexOfKeypress must be 0 for non-printable key");
    // If the keyboard event isn't caused by printable key, its charCode should
    // be 0.
    keyEvent.SetCharCode(0);
  } else {
    if (WidgetKeyboardEvent::IsKeyDownOrKeyDownOnPlugin(aMessage) ||
        WidgetKeyboardEvent::IsKeyUpOrKeyUpOnPlugin(aMessage)) {
      MOZ_RELEASE_ASSERT(!aIndexOfKeypress,
        "aIndexOfKeypress must be 0 for either eKeyDown or eKeyUp");
    } else {
      MOZ_RELEASE_ASSERT(
        !aIndexOfKeypress || aIndexOfKeypress < keyEvent.mKeyValue.Length(),
        "aIndexOfKeypress must be 0 - mKeyValue.Length() - 1");
    }
    wchar_t ch =
      keyEvent.mKeyValue.IsEmpty() ? 0 : keyEvent.mKeyValue[aIndexOfKeypress];
    keyEvent.SetCharCode(static_cast<uint32_t>(ch));
    if (aMessage == eKeyPress) {
      // keyCode of eKeyPress events of printable keys should be always 0.
      keyEvent.mKeyCode = 0;
      // eKeyPress events are dispatched for every character.
      // So, each key value of eKeyPress events should be a character.
      if (ch) {
        keyEvent.mKeyValue.Assign(ch);
      } else {
        keyEvent.mKeyValue.Truncate();
      }
    }
  }
  if (WidgetKeyboardEvent::IsKeyUpOrKeyUpOnPlugin(aMessage)) {
    // mIsRepeat of keyup event must be false.
    keyEvent.mIsRepeat = false;
  }
  // mIsComposing should be initialized later.
  keyEvent.mIsComposing = false;
  if (mInputTransactionType == eNativeInputTransaction) {
    // Copy mNativeKeyEvent here because for safety for other users of
    // AssignKeyEventData(), it doesn't copy this.
    keyEvent.mNativeKeyEvent = aKeyboardEvent.mNativeKeyEvent;
  } else {
    // If it's not a keyboard event for native key event, we should ensure that
    // mNativeKeyEvent and mPluginEvent are null/empty.
    keyEvent.mNativeKeyEvent = nullptr;
    keyEvent.mPluginEvent.Clear();
  }
  // TODO: Manage mUniqueId here.

  // Request the alternative char codes for the key event.
  // eKeyDown also needs alternative char codes because nsXBLWindowKeyHandler
  // needs to check if a following keypress event is reserved by chrome for
  // stopping propagation of its preceding keydown event.
  keyEvent.mAlternativeCharCodes.Clear();
  if ((WidgetKeyboardEvent::IsKeyDownOrKeyDownOnPlugin(aMessage) ||
       aMessage == eKeyPress) &&
      (aNeedsCallback || keyEvent.IsControl() || keyEvent.IsAlt() ||
       keyEvent.IsMeta() || keyEvent.IsOS())) {
    nsCOMPtr<TextEventDispatcherListener> listener =
      do_QueryReferent(mListener);
    if (listener) {
      DebugOnly<WidgetKeyboardEvent> original(keyEvent);
      listener->WillDispatchKeyboardEvent(this, keyEvent, aIndexOfKeypress,
                                          aData);
      MOZ_ASSERT(keyEvent.mMessage ==
                   static_cast<WidgetKeyboardEvent&>(original).mMessage);
      MOZ_ASSERT(keyEvent.mKeyCode ==
                   static_cast<WidgetKeyboardEvent&>(original).mKeyCode);
      MOZ_ASSERT(keyEvent.mLocation ==
                   static_cast<WidgetKeyboardEvent&>(original).mLocation);
      MOZ_ASSERT(keyEvent.mIsRepeat ==
                   static_cast<WidgetKeyboardEvent&>(original).mIsRepeat);
      MOZ_ASSERT(keyEvent.mIsComposing ==
                   static_cast<WidgetKeyboardEvent&>(original).mIsComposing);
      MOZ_ASSERT(keyEvent.mKeyNameIndex ==
                   static_cast<WidgetKeyboardEvent&>(original).mKeyNameIndex);
      MOZ_ASSERT(keyEvent.mCodeNameIndex ==
                   static_cast<WidgetKeyboardEvent&>(original).mCodeNameIndex);
      MOZ_ASSERT(keyEvent.mKeyValue ==
                   static_cast<WidgetKeyboardEvent&>(original).mKeyValue);
      MOZ_ASSERT(keyEvent.mCodeValue ==
                   static_cast<WidgetKeyboardEvent&>(original).mCodeValue);
    }
  }

  if (sDispatchKeyPressEventsOnlySystemGroupInContent &&
      keyEvent.mMessage == eKeyPress &&
      !keyEvent.ShouldKeyPressEventBeFiredOnContent()) {
    // Note that even if we set it to true, this may be overwritten by
    // PresShell::DispatchEventToDOM().
    keyEvent.mFlags.mOnlySystemGroupDispatchInContent = true;
  }

  DispatchInputEvent(mWidget, keyEvent, aStatus);
  return true;
}

bool
TextEventDispatcher::MaybeDispatchKeypressEvents(
                       const WidgetKeyboardEvent& aKeyboardEvent,
                       nsEventStatus& aStatus,
                       void* aData,
                       bool aNeedsCallback)
{
  // If the key event was consumed, keypress event shouldn't be fired.
  if (aStatus == nsEventStatus_eConsumeNoDefault) {
    return false;
  }

  // If the key shouldn't cause keypress events, don't fire them.
  if (!aKeyboardEvent.ShouldCauseKeypressEvents()) {
    return false;
  }

  // If the key isn't a printable key or just inputting one character or
  // no character, we should dispatch only one keypress.  Otherwise, i.e.,
  // if the key is a printable key and inputs multiple characters, keypress
  // event should be dispatched the count of inputting characters times.
  size_t keypressCount =
    aKeyboardEvent.mKeyNameIndex != KEY_NAME_INDEX_USE_STRING ?
      1 : std::max(static_cast<nsAString::size_type>(1),
                   aKeyboardEvent.mKeyValue.Length());
  bool isDispatched = false;
  bool consumed = false;
  for (size_t i = 0; i < keypressCount; i++) {
    aStatus = nsEventStatus_eIgnore;
    if (!DispatchKeyboardEventInternal(eKeyPress, aKeyboardEvent,
                                       aStatus, aData, i, aNeedsCallback)) {
      // The widget must have been gone.
      break;
    }
    isDispatched = true;
    if (!consumed) {
      consumed = (aStatus == nsEventStatus_eConsumeNoDefault);
    }
  }

  // If one of the keypress event was consumed, return ConsumeNoDefault.
  if (consumed) {
    aStatus = nsEventStatus_eConsumeNoDefault;
  }

  return isDispatched;
}

/******************************************************************************
 * TextEventDispatcher::PendingComposition
 *****************************************************************************/

TextEventDispatcher::PendingComposition::PendingComposition()
{
  Clear();
}

void
TextEventDispatcher::PendingComposition::Clear()
{
  mString.Truncate();
  mClauses = nullptr;
  mCaret.mRangeType = TextRangeType::eUninitialized;
  mReplacedNativeLineBreakers = false;
}

void
TextEventDispatcher::PendingComposition::EnsureClauseArray()
{
  if (mClauses) {
    return;
  }
  mClauses = new TextRangeArray();
}

nsresult
TextEventDispatcher::PendingComposition::SetString(const nsAString& aString)
{
  MOZ_ASSERT(!mReplacedNativeLineBreakers);
  mString = aString;
  return NS_OK;
}

nsresult
TextEventDispatcher::PendingComposition::AppendClause(
                                           uint32_t aLength,
                                           TextRangeType aTextRangeType)
{
  MOZ_ASSERT(!mReplacedNativeLineBreakers);

  if (NS_WARN_IF(!aLength)) {
    return NS_ERROR_INVALID_ARG;
  }

  switch (aTextRangeType) {
    case TextRangeType::eRawClause:
    case TextRangeType::eSelectedRawClause:
    case TextRangeType::eConvertedClause:
    case TextRangeType::eSelectedClause: {
      EnsureClauseArray();
      TextRange textRange;
      textRange.mStartOffset =
        mClauses->IsEmpty() ? 0 : mClauses->LastElement().mEndOffset;
      textRange.mEndOffset = textRange.mStartOffset + aLength;
      textRange.mRangeType = aTextRangeType;
      mClauses->AppendElement(textRange);
      return NS_OK;
    }
    default:
      return NS_ERROR_INVALID_ARG;
  }
}

nsresult
TextEventDispatcher::PendingComposition::SetCaret(uint32_t aOffset,
                                                  uint32_t aLength)
{
  MOZ_ASSERT(!mReplacedNativeLineBreakers);

  mCaret.mStartOffset = aOffset;
  mCaret.mEndOffset = mCaret.mStartOffset + aLength;
  mCaret.mRangeType = TextRangeType::eCaret;
  return NS_OK;
}

nsresult
TextEventDispatcher::PendingComposition::Set(const nsAString& aString,
                                             const TextRangeArray* aRanges)
{
  Clear();

  nsresult rv = SetString(aString);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  if (!aRanges || aRanges->IsEmpty()) {
    // Create dummy range if mString isn't empty.
    if (!mString.IsEmpty()) {
      rv = AppendClause(mString.Length(), TextRangeType::eRawClause);
      if (NS_WARN_IF(NS_FAILED(rv))) {
        return rv;
      }
      ReplaceNativeLineBreakers();
    }
    return NS_OK;
  }

  // Adjust offsets in the ranges for XP linefeed character (only \n).
  for (uint32_t i = 0; i < aRanges->Length(); ++i) {
    TextRange range = aRanges->ElementAt(i);
    if (range.mRangeType == TextRangeType::eCaret) {
      mCaret = range;
    } else {
      EnsureClauseArray();
      mClauses->AppendElement(range);
    }
  }
  ReplaceNativeLineBreakers();
  return NS_OK;
}

void
TextEventDispatcher::PendingComposition::ReplaceNativeLineBreakers()
{
  mReplacedNativeLineBreakers = true;

  // If the composition string is empty, we don't need to do anything.
  if (mString.IsEmpty()) {
    return;
  }

  nsAutoString nativeString(mString);
  // Don't expose CRLF nor CR to web contents, instead, use LF.
  mString.ReplaceSubstring(NS_LITERAL_STRING("\r\n"), NS_LITERAL_STRING("\n"));
  mString.ReplaceSubstring(NS_LITERAL_STRING("\r"), NS_LITERAL_STRING("\n"));

  // If the length isn't changed, we don't need to adjust any offset and length
  // of mClauses nor mCaret.
  if (nativeString.Length() == mString.Length()) {
    return;
  }

  if (mClauses) {
    for (TextRange& clause : *mClauses) {
      AdjustRange(clause, nativeString);
    }
  }
  if (mCaret.mRangeType == TextRangeType::eCaret) {
    AdjustRange(mCaret, nativeString);
  }
}

// static
void
TextEventDispatcher::PendingComposition::AdjustRange(
                                           TextRange& aRange,
                                           const nsAString& aNativeString)
{
  TextRange nativeRange = aRange;
  // XXX Following code wastes runtime cost because this causes computing
  //     mStartOffset for each clause from the start of composition string.
  //     If we'd make TextRange have only its length, we don't need to do
  //     this.  However, this must not be so serious problem because
  //     composition string is usually short and separated as a few clauses.
  if (nativeRange.mStartOffset > 0) {
    nsAutoString preText(
      Substring(aNativeString, 0, nativeRange.mStartOffset));
    preText.ReplaceSubstring(NS_LITERAL_STRING("\r\n"),
                             NS_LITERAL_STRING("\n"));
    aRange.mStartOffset = preText.Length();
  }
  if (nativeRange.Length() == 0) {
    aRange.mEndOffset = aRange.mStartOffset;
  } else {
    nsAutoString clause(
      Substring(aNativeString, nativeRange.mStartOffset, nativeRange.Length()));
    clause.ReplaceSubstring(NS_LITERAL_STRING("\r\n"),
                            NS_LITERAL_STRING("\n"));
    aRange.mEndOffset = aRange.mStartOffset + clause.Length();
  }
}

nsresult
TextEventDispatcher::PendingComposition::Flush(
                                           TextEventDispatcher* aDispatcher,
                                           nsEventStatus& aStatus,
                                           const WidgetEventTime* aEventTime)
{
  aStatus = nsEventStatus_eIgnore;

  nsresult rv = aDispatcher->GetState();
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  if (mClauses && !mClauses->IsEmpty() &&
      mClauses->LastElement().mEndOffset != mString.Length()) {
    NS_WARNING("Sum of length of the all clauses must be same as the string "
               "length");
    Clear();
    return NS_ERROR_ILLEGAL_VALUE;
  }
  if (mCaret.mRangeType == TextRangeType::eCaret) {
    if (mCaret.mEndOffset > mString.Length()) {
      NS_WARNING("Caret position is out of the composition string");
      Clear();
      return NS_ERROR_ILLEGAL_VALUE;
    }
    EnsureClauseArray();
    mClauses->AppendElement(mCaret);
  }

  // If the composition string is set without Set(), we need to replace native
  // line breakers in the composition string with XP line breaker.
  if (!mReplacedNativeLineBreakers) {
    ReplaceNativeLineBreakers();
  }

  RefPtr<TextEventDispatcher> kungFuDeathGrip(aDispatcher);
  nsCOMPtr<nsIWidget> widget(aDispatcher->mWidget);
  WidgetCompositionEvent compChangeEvent(true, eCompositionChange, widget);
  aDispatcher->InitEvent(compChangeEvent);
  if (aEventTime) {
    compChangeEvent.AssignEventTime(*aEventTime);
  }
  compChangeEvent.mData = mString;
  if (mClauses) {
    MOZ_ASSERT(!mClauses->IsEmpty(),
               "mClauses must be non-empty array when it's not nullptr");
    compChangeEvent.mRanges = mClauses;
  }

  // While this method dispatches a composition event, some other event handler
  // cause more clauses to be added.  So, we should clear pending composition
  // before dispatching the event.
  Clear();

  rv = aDispatcher->StartCompositionAutomaticallyIfNecessary(aStatus,
                                                             aEventTime);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }
  if (aStatus == nsEventStatus_eConsumeNoDefault) {
    return NS_OK;
  }
  rv = aDispatcher->DispatchEvent(widget, compChangeEvent, aStatus);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  return NS_OK;
}

} // namespace widget
} // namespace mozilla