dom/events/TextComposition.cpp
author Masayuki Nakano <masayuki@d-toybox.com>
Tue, 27 Nov 2018 13:26:51 +0000
changeset 507483 8be20508c9d5577ec80c7e181fae203a7f736bc1
parent 484208 37e818a03a1b0be87616b50d702a2e7406cc9172
child 508163 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1288640 - Make TextComposition not dispatch eCompositionChange events (DOM "text" event) in the default group of web content r=smaug The usage of our specific "text" event is enough low (0.0003%). So, let's stop dispatching the event in the default group of web content. Once we release this new behavior, we can get rid of dispatching the event even in chrome. Then, we can optimize the event order for new specs. Differential Revision: https://phabricator.services.mozilla.com/D13034

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 "ContentEventHandler.h"
#include "IMEContentObserver.h"
#include "IMEStateManager.h"
#include "nsContentUtils.h"
#include "nsIContent.h"
#include "nsIPresShell.h"
#include "nsPresContext.h"
#include "mozilla/AutoRestore.h"
#include "mozilla/EditorBase.h"
#include "mozilla/EventDispatcher.h"
#include "mozilla/IMEStateManager.h"
#include "mozilla/MiscEvents.h"
#include "mozilla/Preferences.h"
#include "mozilla/StaticPrefs.h"
#include "mozilla/TextComposition.h"
#include "mozilla/TextEvents.h"
#include "mozilla/Unused.h"
#include "mozilla/dom/TabParent.h"

#ifdef XP_MACOSX
// Some defiens will be conflict with OSX SDK
#define TextRange _TextRange
#define TextRangeArray _TextRangeArray
#define Comment _Comment
#endif

#include "nsPluginInstanceOwner.h"

#ifdef XP_MACOSX
#undef TextRange
#undef TextRangeArray
#undef Comment
#endif

using namespace mozilla::widget;

namespace mozilla {

#define IDEOGRAPHIC_SPACE (NS_LITERAL_STRING(u"\x3000"))

/******************************************************************************
 * TextComposition
 ******************************************************************************/

bool TextComposition::sHandlingSelectionEvent = false;

TextComposition::TextComposition(nsPresContext* aPresContext,
                                 nsINode* aNode,
                                 TabParent* aTabParent,
                                 WidgetCompositionEvent* aCompositionEvent)
  : mPresContext(aPresContext)
  , mNode(aNode)
  , mTabParent(aTabParent)
  , mNativeContext(aCompositionEvent->mNativeIMEContext)
  , mCompositionStartOffset(0)
  , mTargetClauseOffsetInComposition(0)
  , mCompositionStartOffsetInTextNode(UINT32_MAX)
  , mCompositionLengthInTextNode(UINT32_MAX)
  , mIsSynthesizedForTests(aCompositionEvent->mFlags.mIsSynthesizedForTests)
  , mIsComposing(false)
  , mIsEditorHandlingEvent(false)
  , mIsRequestingCommit(false)
  , mIsRequestingCancel(false)
  , mRequestedToCommitOrCancel(false)
  , mHasDispatchedDOMTextEvent(false)
  , mHasReceivedCommitEvent(false)
  , mWasNativeCompositionEndEventDiscarded(false)
  , mAllowControlCharacters(
      Preferences::GetBool("dom.compositionevent.allow_control_characters",
                           false))
  , mWasCompositionStringEmpty(true)
{
  MOZ_ASSERT(aCompositionEvent->mNativeIMEContext.IsValid());
}

void
TextComposition::Destroy()
{
  mPresContext = nullptr;
  mNode = nullptr;
  mTabParent = nullptr;
  mContainerTextNode = nullptr;
  mCompositionStartOffsetInTextNode = UINT32_MAX;
  mCompositionLengthInTextNode = UINT32_MAX;
  // TODO: If the editor is still alive and this is held by it, we should tell
  //       this being destroyed for cleaning up the stuff.
}

bool
TextComposition::IsValidStateForComposition(nsIWidget* aWidget) const
{
  return !Destroyed() && aWidget && !aWidget->Destroyed() &&
         mPresContext->GetPresShell() &&
         !mPresContext->GetPresShell()->IsDestroying();
}

bool
TextComposition::MaybeDispatchCompositionUpdate(
                   const WidgetCompositionEvent* aCompositionEvent)
{
  MOZ_RELEASE_ASSERT(!mTabParent);

  if (!IsValidStateForComposition(aCompositionEvent->mWidget)) {
    return false;
  }

  // Note that we don't need to dispatch eCompositionUpdate event even if
  // mHasDispatchedDOMTextEvent is false and eCompositionCommit event is
  // dispatched with empty string immediately after eCompositionStart
  // because composition string has never been changed from empty string to
  // non-empty string in such composition even if selected string was not
  // empty string (mLastData isn't set to selected text when this receives
  // eCompositionStart).
  if (mLastData == aCompositionEvent->mData) {
    return true;
  }
  CloneAndDispatchAs(aCompositionEvent, eCompositionUpdate);
  return IsValidStateForComposition(aCompositionEvent->mWidget);
}

BaseEventFlags
TextComposition::CloneAndDispatchAs(
                   const WidgetCompositionEvent* aCompositionEvent,
                   EventMessage aMessage,
                   nsEventStatus* aStatus,
                   EventDispatchingCallback* aCallBack)
{
  MOZ_RELEASE_ASSERT(!mTabParent);

  MOZ_ASSERT(IsValidStateForComposition(aCompositionEvent->mWidget),
             "Should be called only when it's safe to dispatch an event");

  WidgetCompositionEvent compositionEvent(aCompositionEvent->IsTrusted(),
                                          aMessage, aCompositionEvent->mWidget);
  compositionEvent.mTime = aCompositionEvent->mTime;
  compositionEvent.mTimeStamp = aCompositionEvent->mTimeStamp;
  compositionEvent.mData = aCompositionEvent->mData;
  compositionEvent.mNativeIMEContext = aCompositionEvent->mNativeIMEContext;
  compositionEvent.mOriginalMessage = aCompositionEvent->mMessage;
  compositionEvent.mFlags.mIsSynthesizedForTests =
    aCompositionEvent->mFlags.mIsSynthesizedForTests;

  nsEventStatus dummyStatus = nsEventStatus_eConsumeNoDefault;
  nsEventStatus* status = aStatus ? aStatus : &dummyStatus;
  if (aMessage == eCompositionUpdate) {
    mLastData = compositionEvent.mData;
    mLastRanges = aCompositionEvent->mRanges;
  }

  DispatchEvent(&compositionEvent, status, aCallBack, aCompositionEvent);
  return compositionEvent.mFlags;
}

void
TextComposition::DispatchEvent(WidgetCompositionEvent* aDispatchEvent,
                               nsEventStatus* aStatus,
                               EventDispatchingCallback* aCallBack,
                               const WidgetCompositionEvent *aOriginalEvent)
{
  nsPluginInstanceOwner::GeneratePluginEvent(aOriginalEvent,
                                             aDispatchEvent);

  if (aDispatchEvent->mMessage == eCompositionChange &&
      StaticPrefs::
        dom_compositionevent_text_dispatch_only_system_group_in_content()) {
    aDispatchEvent->mFlags.mOnlySystemGroupDispatchInContent = true;
  }
  EventDispatcher::Dispatch(mNode, mPresContext,
                            aDispatchEvent, nullptr, aStatus, aCallBack);

  OnCompositionEventDispatched(aDispatchEvent);
}

void
TextComposition::OnCompositionEventDiscarded(
                   WidgetCompositionEvent* aCompositionEvent)
{
  // Note that this method is never called for synthesized events for emulating
  // commit or cancel composition.

  MOZ_ASSERT(aCompositionEvent->IsTrusted(),
             "Shouldn't be called with untrusted event");

  if (mTabParent) {
    // The composition event should be discarded in the child process too.
    Unused << mTabParent->SendCompositionEvent(*aCompositionEvent);
  }

  // XXX If composition events are discarded, should we dispatch them with
  //     runnable event?  However, even if we do so, it might make native IME
  //     confused due to async modification.  Especially when native IME is
  //     TSF.
  if (!aCompositionEvent->CausesDOMCompositionEndEvent()) {
    return;
  }

  mWasNativeCompositionEndEventDiscarded = true;
}

static inline bool
IsControlChar(uint32_t aCharCode)
{
  return aCharCode < ' ' || aCharCode == 0x7F;
}

static size_t
FindFirstControlCharacter(const nsAString& aStr)
{
  const char16_t* sourceBegin = aStr.BeginReading();
  const char16_t* sourceEnd = aStr.EndReading();

  for (const char16_t* source = sourceBegin; source < sourceEnd; ++source) {
    if (*source != '\t' && IsControlChar(*source)) {
      return source - sourceBegin;
    }
  }

  return -1;
}

static void
RemoveControlCharactersFrom(nsAString& aStr, TextRangeArray* aRanges)
{
  size_t firstControlCharOffset = FindFirstControlCharacter(aStr);
  if (firstControlCharOffset == (size_t)-1) {
    return;
  }

  nsAutoString copy(aStr);
  const char16_t* sourceBegin = copy.BeginReading();
  const char16_t* sourceEnd = copy.EndReading();

  char16_t* dest = aStr.BeginWriting();
  if (NS_WARN_IF(!dest)) {
    return;
  }

  char16_t* curDest = dest + firstControlCharOffset;
  size_t i = firstControlCharOffset;
  for (const char16_t* source = sourceBegin + firstControlCharOffset;
       source < sourceEnd; ++source) {
    if (*source == '\t' || *source == '\n' || !IsControlChar(*source)) {
      *curDest = *source;
      ++curDest;
      ++i;
    } else if (aRanges) {
      aRanges->RemoveCharacter(i);
    }
  }

  aStr.SetLength(curDest - dest);
}

void
TextComposition::DispatchCompositionEvent(
                   WidgetCompositionEvent* aCompositionEvent,
                   nsEventStatus* aStatus,
                   EventDispatchingCallback* aCallBack,
                   bool aIsSynthesized)
{
  mWasCompositionStringEmpty = mString.IsEmpty();

  if (aCompositionEvent->IsFollowedByCompositionEnd()) {
    mHasReceivedCommitEvent = true;
  }

  // If this instance has requested to commit or cancel composition but
  // is not synthesizing commit event, that means that the IME commits or
  // cancels the composition asynchronously.  Typically, iBus behaves so.
  // Then, synthesized events which were dispatched immediately after
  // the request has already committed our editor's composition string and
  // told it to web apps.  Therefore, we should ignore the delayed events.
  if (mRequestedToCommitOrCancel && !aIsSynthesized) {
    *aStatus = nsEventStatus_eConsumeNoDefault;
    return;
  }

  // If the content is a container of TabParent, composition should be in the
  // remote process.
  if (mTabParent) {
    Unused << mTabParent->SendCompositionEvent(*aCompositionEvent);
    aCompositionEvent->StopPropagation();
    if (aCompositionEvent->CausesDOMTextEvent()) {
      mLastData = aCompositionEvent->mData;
      mLastRanges = aCompositionEvent->mRanges;
      // Although, the composition event hasn't been actually handled yet,
      // emulate an editor to be handling the composition event.
      EditorWillHandleCompositionChangeEvent(aCompositionEvent);
      EditorDidHandleCompositionChangeEvent();
    }
    return;
  }

  if (!mAllowControlCharacters) {
    RemoveControlCharactersFrom(aCompositionEvent->mData,
                                aCompositionEvent->mRanges);
  }
  if (aCompositionEvent->mMessage == eCompositionCommitAsIs) {
    NS_ASSERTION(!aCompositionEvent->mRanges,
                 "mRanges of eCompositionCommitAsIs should be null");
    aCompositionEvent->mRanges = nullptr;
    NS_ASSERTION(aCompositionEvent->mData.IsEmpty(),
                 "mData of eCompositionCommitAsIs should be empty string");
    bool removePlaceholderCharacter =
      Preferences::GetBool("intl.ime.remove_placeholder_character_at_commit",
                           false);
    if (removePlaceholderCharacter && mLastData == IDEOGRAPHIC_SPACE) {
      // If the last data is an ideographic space (FullWidth space), it might be
      // a placeholder character of some Chinese IME.  So, committing with
      // this data might not be expected by users.  Let's use empty string.
      aCompositionEvent->mData.Truncate();
    } else {
      aCompositionEvent->mData = mLastData;
    }
  } else if (aCompositionEvent->mMessage == eCompositionCommit) {
    NS_ASSERTION(!aCompositionEvent->mRanges,
                 "mRanges of eCompositionCommit should be null");
    aCompositionEvent->mRanges = nullptr;
  }

  if (!IsValidStateForComposition(aCompositionEvent->mWidget)) {
    *aStatus = nsEventStatus_eConsumeNoDefault;
    return;
  }

  // IME may commit composition with empty string for a commit request or
  // with non-empty string for a cancel request.  We should prevent such
  // unexpected result.  E.g., web apps may be confused if they implement
  // autocomplete which attempts to commit composition forcibly when the user
  // selects one of suggestions but composition string is cleared by IME.
  // Note that most Chinese IMEs don't expose actual composition string to us.
  // They typically tell us an IDEOGRAPHIC SPACE or empty string as composition
  // string.  Therefore, we should hack it only when:
  // 1. committing string is empty string at requesting commit but the last
  //    data isn't IDEOGRAPHIC SPACE.
  // 2. non-empty string is committed at requesting cancel.
  if (!aIsSynthesized && (mIsRequestingCommit || mIsRequestingCancel)) {
    nsString* committingData = nullptr;
    switch (aCompositionEvent->mMessage) {
      case eCompositionEnd:
      case eCompositionChange:
      case eCompositionCommitAsIs:
      case eCompositionCommit:
        committingData = &aCompositionEvent->mData;
        break;
      default:
        NS_WARNING("Unexpected event comes during committing or "
                   "canceling composition");
        break;
    }
    if (committingData) {
      if (mIsRequestingCommit && committingData->IsEmpty() &&
          mLastData != IDEOGRAPHIC_SPACE) {
        committingData->Assign(mLastData);
      } else if (mIsRequestingCancel && !committingData->IsEmpty()) {
        committingData->Truncate();
      }
    }
  }

  bool dispatchEvent = true;
  bool dispatchDOMTextEvent = aCompositionEvent->CausesDOMTextEvent();

  // When mIsComposing is false but the committing string is different from
  // the last data (E.g., previous eCompositionChange event made the
  // composition string empty or didn't have clause information), we don't
  // need to dispatch redundant DOM text event.  (But note that we need to
  // dispatch eCompositionChange event if we have not dispatched
  // eCompositionChange event yet and commit string replaces selected string
  // with empty string since selected string hasn't been replaced with empty
  // string yet.)
  if (dispatchDOMTextEvent &&
      aCompositionEvent->mMessage != eCompositionChange &&
      !mIsComposing && mHasDispatchedDOMTextEvent &&
      mLastData == aCompositionEvent->mData) {
    dispatchEvent = dispatchDOMTextEvent = false;
  }

  // widget may dispatch redundant eCompositionChange event
  // which modifies neither composition string, clauses nor caret
  // position.  In such case, we shouldn't dispatch DOM events.
  if (dispatchDOMTextEvent &&
      aCompositionEvent->mMessage == eCompositionChange &&
      mLastData == aCompositionEvent->mData &&
      mRanges && aCompositionEvent->mRanges &&
      mRanges->Equals(*aCompositionEvent->mRanges)) {
    dispatchEvent = dispatchDOMTextEvent = false;
  }

  if (dispatchDOMTextEvent) {
    if (!MaybeDispatchCompositionUpdate(aCompositionEvent)) {
      return;
    }
  }

  if (dispatchEvent) {
    // If the composition event should cause a DOM text event, we should
    // overwrite the event message as eCompositionChange because due to
    // the limitation of mapping between event messages and DOM event types,
    // we cannot map multiple event messages to a DOM event type.
    if (dispatchDOMTextEvent &&
        aCompositionEvent->mMessage != eCompositionChange) {
      mHasDispatchedDOMTextEvent = true;
      aCompositionEvent->mFlags =
        CloneAndDispatchAs(aCompositionEvent, eCompositionChange,
                           aStatus, aCallBack);
    } else {
      if (aCompositionEvent->mMessage == eCompositionChange) {
        mHasDispatchedDOMTextEvent = true;
      }
      DispatchEvent(aCompositionEvent, aStatus, aCallBack);
    }
  } else {
    *aStatus = nsEventStatus_eConsumeNoDefault;
  }

  if (!IsValidStateForComposition(aCompositionEvent->mWidget)) {
    return;
  }

  // Emulate editor behavior of compositionchange event (DOM text event) handler
  // if no editor handles composition events.
  if (dispatchDOMTextEvent && !HasEditor()) {
    EditorWillHandleCompositionChangeEvent(aCompositionEvent);
    EditorDidHandleCompositionChangeEvent();
  }

  if (aCompositionEvent->CausesDOMCompositionEndEvent()) {
    // Dispatch a compositionend event if it's necessary.
    if (aCompositionEvent->mMessage != eCompositionEnd) {
      CloneAndDispatchAs(aCompositionEvent, eCompositionEnd);
    }
    MOZ_ASSERT(!mIsComposing, "Why is the editor still composing?");
    MOZ_ASSERT(!HasEditor(), "Why does the editor still keep to hold this?");
  }

  MaybeNotifyIMEOfCompositionEventHandled(aCompositionEvent);
}

// static
void
TextComposition::HandleSelectionEvent(nsPresContext* aPresContext,
                                      TabParent* aTabParent,
                                      WidgetSelectionEvent* aSelectionEvent)
{
  // If the content is a container of TabParent, composition should be in the
  // remote process.
  if (aTabParent) {
    Unused << aTabParent->SendSelectionEvent(*aSelectionEvent);
    aSelectionEvent->StopPropagation();
    return;
  }

  ContentEventHandler handler(aPresContext);
  AutoRestore<bool> saveHandlingSelectionEvent(sHandlingSelectionEvent);
  sHandlingSelectionEvent = true;
  // XXX During setting selection, a selection listener may change selection
  //     again.  In such case, sHandlingSelectionEvent doesn't indicate if
  //     the selection change is caused by a selection event.  However, it
  //     must be non-realistic scenario.
  handler.OnSelectionEvent(aSelectionEvent);
}

uint32_t
TextComposition::GetSelectionStartOffset()
{
  nsCOMPtr<nsIWidget> widget = mPresContext->GetRootWidget();
  WidgetQueryContentEvent selectedTextEvent(true, eQuerySelectedText, widget);
  // Due to a bug of widget, mRanges may not be nullptr even though composition
  // string is empty.  So, we need to check it here for avoiding to return
  // odd start offset.
  if (!mLastData.IsEmpty() && mRanges && mRanges->HasClauses()) {
    selectedTextEvent.InitForQuerySelectedText(
                        ToSelectionType(mRanges->GetFirstClause()->mRangeType));
  } else {
    NS_WARNING_ASSERTION(
      !mLastData.IsEmpty() || !mRanges || !mRanges->HasClauses(),
      "Shouldn't have empty clause info when composition string is empty");
    selectedTextEvent.InitForQuerySelectedText(SelectionType::eNormal);
  }

  // The editor which has this composition is observed by active
  // IMEContentObserver, we can use the cache of it.
  RefPtr<IMEContentObserver> contentObserver =
    IMEStateManager::GetActiveContentObserver();
  bool doQuerySelection = true;
  if (contentObserver) {
    if (contentObserver->IsManaging(this)) {
      doQuerySelection = false;
      contentObserver->HandleQueryContentEvent(&selectedTextEvent);
    }
    // If another editor already has focus, we cannot retrieve selection
    // in the editor which has this composition...
    else if (NS_WARN_IF(contentObserver->GetPresContext() == mPresContext)) {
      return 0;  // XXX Is this okay?
    }
  }

  // Otherwise, using slow path (i.e., compute every time with
  // ContentEventHandler)
  if (doQuerySelection) {
    ContentEventHandler handler(mPresContext);
    handler.HandleQueryContentEvent(&selectedTextEvent);
  }

  if (NS_WARN_IF(!selectedTextEvent.mSucceeded)) {
    return 0; // XXX Is this okay?
  }
  return selectedTextEvent.mReply.mOffset;
}

void
TextComposition::OnCompositionEventDispatched(
                   const WidgetCompositionEvent* aCompositionEvent)
{
  MOZ_RELEASE_ASSERT(!mTabParent);

  if (!IsValidStateForComposition(aCompositionEvent->mWidget)) {
    return;
  }

  // Every composition event may cause changing composition start offset,
  // especially when there is no composition string.  Therefore, we need to
  // update mCompositionStartOffset with the latest offset.

  MOZ_ASSERT(aCompositionEvent->mMessage != eCompositionStart ||
               mWasCompositionStringEmpty,
             "mWasCompositionStringEmpty should be true if the dispatched "
             "event is eCompositionStart");

  if (mWasCompositionStringEmpty &&
      !aCompositionEvent->CausesDOMCompositionEndEvent()) {
    // If there was no composition string, current selection start may be the
    // offset for inserting composition string.
    // Update composition start offset with current selection start.
    mCompositionStartOffset = GetSelectionStartOffset();
    mTargetClauseOffsetInComposition = 0;
  }

  if (aCompositionEvent->CausesDOMTextEvent()) {
    mTargetClauseOffsetInComposition = aCompositionEvent->TargetClauseOffset();
  }
}

void
TextComposition::OnStartOffsetUpdatedInChild(uint32_t aStartOffset)
{
  mCompositionStartOffset = aStartOffset;
}

void
TextComposition::MaybeNotifyIMEOfCompositionEventHandled(
                   const WidgetCompositionEvent* aCompositionEvent)
{
  if (aCompositionEvent->mMessage != eCompositionStart &&
      !aCompositionEvent->CausesDOMTextEvent()) {
    return;
  }

  RefPtr<IMEContentObserver> contentObserver =
    IMEStateManager::GetActiveContentObserver();
  // When IMEContentObserver is managing the editor which has this composition,
  // composition event handled notification should be sent after the observer
  // notifies all pending notifications.  Therefore, we should use it.
  // XXX If IMEContentObserver suddenly loses focus after here and notifying
  //     widget of pending notifications, we won't notify widget of composition
  //     event handled.  Although, this is a bug but it should be okay since
  //     destroying IMEContentObserver notifies IME of blur.  So, native IME
  //     handler can treat it as this notification too.
  if (contentObserver && contentObserver->IsManaging(this)) {
    contentObserver->MaybeNotifyCompositionEventHandled();
    return;
  }
  // Otherwise, e.g., this composition is in non-active window, we should
  // notify widget directly.
  NotifyIME(NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED);
}

void
TextComposition::DispatchCompositionEventRunnable(EventMessage aEventMessage,
                                                  const nsAString& aData,
                                                  bool aIsSynthesizingCommit)
{
  nsContentUtils::AddScriptRunner(
    new CompositionEventDispatcher(this, mNode, aEventMessage, aData,
                                   aIsSynthesizingCommit));
}

nsresult
TextComposition::RequestToCommit(nsIWidget* aWidget, bool aDiscard)
{
  // If this composition is already requested to be committed or canceled,
  // or has already finished in IME, we don't need to request it again because
  // request from this instance shouldn't cause committing nor canceling current
  // composition in IME, and even if the first request failed, new request
  // won't success, probably.  And we shouldn't synthesize events for
  // committing or canceling composition twice or more times.
  if (!CanRequsetIMEToCommitOrCancelComposition()) {
    return NS_OK;
  }

  RefPtr<TextComposition> kungFuDeathGrip(this);
  const nsAutoString lastData(mLastData);

  {
    AutoRestore<bool> saveRequestingCancel(mIsRequestingCancel);
    AutoRestore<bool> saveRequestingCommit(mIsRequestingCommit);
    if (aDiscard) {
      mIsRequestingCancel = true;
      mIsRequestingCommit = false;
    } else {
      mIsRequestingCancel = false;
      mIsRequestingCommit = true;
    }
    // FYI: CompositionEvents caused by a call of NotifyIME() may be
    //      discarded by PresShell if it's not safe to dispatch the event.
    nsresult rv =
      aWidget->NotifyIME(IMENotification(aDiscard ?
                                           REQUEST_TO_CANCEL_COMPOSITION :
                                           REQUEST_TO_COMMIT_COMPOSITION));
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  }

  mRequestedToCommitOrCancel = true;

  // If the request is performed synchronously, this must be already destroyed.
  if (Destroyed()) {
    return NS_OK;
  }

  // Otherwise, synthesize the commit in content.
  nsAutoString data(aDiscard ? EmptyString() : lastData);
  if (data == mLastData) {
    DispatchCompositionEventRunnable(eCompositionCommitAsIs, EmptyString(),
                                     true);
  } else {
    DispatchCompositionEventRunnable(eCompositionCommit, data, true);
  }
  return NS_OK;
}

nsresult
TextComposition::NotifyIME(IMEMessage aMessage)
{
  NS_ENSURE_TRUE(mPresContext, NS_ERROR_NOT_AVAILABLE);
  return IMEStateManager::NotifyIME(aMessage, mPresContext, mTabParent);
}

void
TextComposition::EditorWillHandleCompositionChangeEvent(
                   const WidgetCompositionEvent* aCompositionChangeEvent)
{
  mIsComposing = aCompositionChangeEvent->IsComposing();
  mRanges = aCompositionChangeEvent->mRanges;
  mIsEditorHandlingEvent = true;

  MOZ_ASSERT(mLastData == aCompositionChangeEvent->mData,
    "The text of a compositionchange event must be same as previous data "
    "attribute value of the latest compositionupdate event");
}

void
TextComposition::OnEditorDestroyed()
{
  MOZ_RELEASE_ASSERT(!mTabParent);

  MOZ_ASSERT(!mIsEditorHandlingEvent,
             "The editor should have stopped listening events");
  nsCOMPtr<nsIWidget> widget = GetWidget();
  if (NS_WARN_IF(!widget)) {
    // XXX If this could happen, how do we notify IME of destroying the editor?
    return;
  }

  // Try to cancel the composition.
  RequestToCommit(widget, true);
}

void
TextComposition::EditorDidHandleCompositionChangeEvent()
{
  mString = mLastData;
  mIsEditorHandlingEvent = false;
}

void
TextComposition::StartHandlingComposition(EditorBase* aEditorBase)
{
  MOZ_RELEASE_ASSERT(!mTabParent);

  MOZ_ASSERT(!HasEditor(), "There is a handling editor already");
  mEditorBaseWeak = do_GetWeakReference(static_cast<nsIEditor*>(aEditorBase));
}

void
TextComposition::EndHandlingComposition(EditorBase* aEditorBase)
{
  MOZ_RELEASE_ASSERT(!mTabParent);

#ifdef DEBUG
  RefPtr<EditorBase> editorBase = GetEditorBase();
  MOZ_ASSERT(editorBase == aEditorBase,
             "Another editor handled the composition?");
#endif // #ifdef DEBUG
  mEditorBaseWeak = nullptr;
}

already_AddRefed<EditorBase>
TextComposition::GetEditorBase() const
{
  nsCOMPtr<nsIEditor> editor = do_QueryReferent(mEditorBaseWeak);
  RefPtr<EditorBase> editorBase = static_cast<EditorBase*>(editor.get());
  return editorBase.forget();
}

bool
TextComposition::HasEditor() const
{
  return mEditorBaseWeak && mEditorBaseWeak->IsAlive();
}

/******************************************************************************
 * TextComposition::CompositionEventDispatcher
 ******************************************************************************/

TextComposition::CompositionEventDispatcher::CompositionEventDispatcher(
  TextComposition* aComposition,
  nsINode* aEventTarget,
  EventMessage aEventMessage,
  const nsAString& aData,
  bool aIsSynthesizedEvent)
  : Runnable("TextComposition::CompositionEventDispatcher")
  , mTextComposition(aComposition)
  , mEventTarget(aEventTarget)
  , mData(aData)
  , mEventMessage(aEventMessage)
  , mIsSynthesizedEvent(aIsSynthesizedEvent)
{
}

NS_IMETHODIMP
TextComposition::CompositionEventDispatcher::Run()
{
  // The widget can be different from the widget which has dispatched
  // composition events because GetWidget() returns a widget which is proper
  // for calling NotifyIME().  However, this must no be problem since both
  // widget should share native IME context.  Therefore, even if an event
  // handler uses the widget for requesting IME to commit or cancel, it works.
  nsCOMPtr<nsIWidget> widget(mTextComposition->GetWidget());
  if (!mTextComposition->IsValidStateForComposition(widget)) {
    return NS_OK; // cannot dispatch any events anymore
  }

  RefPtr<nsPresContext> presContext = mTextComposition->mPresContext;
  nsEventStatus status = nsEventStatus_eIgnore;
  switch (mEventMessage) {
    case eCompositionStart: {
      WidgetCompositionEvent compStart(true, eCompositionStart, widget);
      compStart.mNativeIMEContext = mTextComposition->mNativeContext;
      WidgetQueryContentEvent selectedText(true, eQuerySelectedText, widget);
      ContentEventHandler handler(presContext);
      handler.OnQuerySelectedText(&selectedText);
      NS_ASSERTION(selectedText.mSucceeded, "Failed to get selected text");
      compStart.mData = selectedText.mReply.mString;
      compStart.mFlags.mIsSynthesizedForTests =
        mTextComposition->IsSynthesizedForTests();
      IMEStateManager::DispatchCompositionEvent(mEventTarget, presContext,
                                                &compStart, &status, nullptr,
                                                mIsSynthesizedEvent);
      break;
    }
    case eCompositionChange:
    case eCompositionCommitAsIs:
    case eCompositionCommit: {
      WidgetCompositionEvent compEvent(true, mEventMessage, widget);
      compEvent.mNativeIMEContext = mTextComposition->mNativeContext;
      if (mEventMessage != eCompositionCommitAsIs) {
        compEvent.mData = mData;
      }
      compEvent.mFlags.mIsSynthesizedForTests =
        mTextComposition->IsSynthesizedForTests();
      IMEStateManager::DispatchCompositionEvent(mEventTarget, presContext,
                                                &compEvent, &status, nullptr,
                                                mIsSynthesizedEvent);
      break;
    }
    default:
      MOZ_CRASH("Unsupported event");
  }
  return NS_OK;
}

/******************************************************************************
 * TextCompositionArray
 ******************************************************************************/

TextCompositionArray::index_type
TextCompositionArray::IndexOf(const NativeIMEContext& aNativeIMEContext)
{
  if (!aNativeIMEContext.IsValid()) {
    return NoIndex;
  }
  for (index_type i = Length(); i > 0; --i) {
    if (ElementAt(i - 1)->GetNativeIMEContext() == aNativeIMEContext) {
      return i - 1;
    }
  }
  return NoIndex;
}

TextCompositionArray::index_type
TextCompositionArray::IndexOf(nsIWidget* aWidget)
{
  return IndexOf(aWidget->GetNativeIMEContext());
}

TextCompositionArray::index_type
TextCompositionArray::IndexOf(nsPresContext* aPresContext)
{
  for (index_type i = Length(); i > 0; --i) {
    if (ElementAt(i - 1)->GetPresContext() == aPresContext) {
      return i - 1;
    }
  }
  return NoIndex;
}

TextCompositionArray::index_type
TextCompositionArray::IndexOf(nsPresContext* aPresContext,
                              nsINode* aNode)
{
  index_type index = IndexOf(aPresContext);
  if (index == NoIndex) {
    return NoIndex;
  }
  nsINode* node = ElementAt(index)->GetEventTargetNode();
  return node == aNode ? index : NoIndex;
}

TextComposition*
TextCompositionArray::GetCompositionFor(nsIWidget* aWidget)
{
  index_type i = IndexOf(aWidget);
  if (i == NoIndex) {
    return nullptr;
  }
  return ElementAt(i);
}

TextComposition*
TextCompositionArray::GetCompositionFor(
                        const WidgetCompositionEvent* aCompositionEvent)
{
  index_type i = IndexOf(aCompositionEvent->mNativeIMEContext);
  if (i == NoIndex) {
    return nullptr;
  }
  return ElementAt(i);
}

TextComposition*
TextCompositionArray::GetCompositionFor(nsPresContext* aPresContext)
{
  index_type i = IndexOf(aPresContext);
  if (i == NoIndex) {
    return nullptr;
  }
  return ElementAt(i);
}

TextComposition*
TextCompositionArray::GetCompositionFor(nsPresContext* aPresContext,
                                           nsINode* aNode)
{
  index_type i = IndexOf(aPresContext, aNode);
  if (i == NoIndex) {
    return nullptr;
  }
  return ElementAt(i);
}

TextComposition*
TextCompositionArray::GetCompositionInContent(nsPresContext* aPresContext,
                                              nsIContent* aContent)
{
  // There should be only one composition per content object.
  for (index_type i = Length(); i > 0; --i) {
    nsINode* node = ElementAt(i - 1)->GetEventTargetNode();
    if (node && nsContentUtils::ContentIsDescendantOf(node, aContent)) {
      return ElementAt(i - 1);
    }
  }
  return nullptr;
}

} // namespace mozilla