fune/accessible/base/AccEvent.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=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 "AccEvent.h"

#include "nsAccUtils.h"
#include "xpcAccEvents.h"
#include "States.h"
#include "TextRange.h"
#include "xpcAccessibleDocument.h"
#include "xpcAccessibleTextRange.h"

#include "mozilla/dom/Selection.h"
#include "mozilla/dom/UserActivation.h"

#include "nsComponentManagerUtils.h"
#include "nsIMutableArray.h"

using namespace mozilla;
using namespace mozilla::a11y;

static_assert(static_cast<bool>(eNoUserInput) == false &&
                  static_cast<bool>(eFromUserInput) == true,
              "EIsFromUserInput cannot be casted to bool");

////////////////////////////////////////////////////////////////////////////////
// AccEvent
////////////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////////////
// AccEvent constructors

AccEvent::AccEvent(uint32_t aEventType, LocalAccessible* aAccessible,
                   EIsFromUserInput aIsFromUserInput, EEventRule aEventRule)
    : mEventType(aEventType), mEventRule(aEventRule), mAccessible(aAccessible) {
  if (aIsFromUserInput == eAutoDetect) {
    mIsFromUserInput = dom::UserActivation::IsHandlingUserInput();
  } else {
    mIsFromUserInput = aIsFromUserInput == eFromUserInput ? true : false;
  }
}

////////////////////////////////////////////////////////////////////////////////
// AccEvent cycle collection

NS_IMPL_CYCLE_COLLECTION_CLASS(AccEvent)

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(AccEvent)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mAccessible)
  if (AccTreeMutationEvent* tmEvent = downcast_accEvent(tmp)) {
    tmEvent->SetNextEvent(nullptr);
    tmEvent->SetPrevEvent(nullptr);
  }
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(AccEvent)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAccessible)
  if (AccTreeMutationEvent* tmEvent = downcast_accEvent(tmp)) {
    CycleCollectionNoteChild(cb, tmEvent->NextEvent(), "mNext");
    CycleCollectionNoteChild(cb, tmEvent->PrevEvent(), "mPrevEvent");
  }
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
// AccTextChangeEvent
////////////////////////////////////////////////////////////////////////////////

// Note: we pass in eAllowDupes to the base class because we don't support text
// events coalescence. We fire delayed text change events in DocAccessible but
// we continue to base the event off the accessible object rather than just the
// node. This means we won't try to create an accessible based on the node when
// we are ready to fire the event and so we will no longer assert at that point
// if the node was removed from the document. Either way, the AT won't work with
// a defunct accessible so the behaviour should be equivalent.
AccTextChangeEvent::AccTextChangeEvent(LocalAccessible* aAccessible,
                                       int32_t aStart,
                                       const nsAString& aModifiedText,
                                       bool aIsInserted,
                                       EIsFromUserInput aIsFromUserInput)
    : AccEvent(
          aIsInserted
              ? static_cast<uint32_t>(nsIAccessibleEvent::EVENT_TEXT_INSERTED)
              : static_cast<uint32_t>(nsIAccessibleEvent::EVENT_TEXT_REMOVED),
          aAccessible, aIsFromUserInput, eAllowDupes),
      mStart(aStart),
      mIsInserted(aIsInserted),
      mModifiedText(aModifiedText) {
  // XXX We should use IsFromUserInput here, but that isn't always correct
  // when the text change isn't related to content insertion or removal.
  mIsFromUserInput =
      mAccessible->State() & (states::FOCUSED | states::EDITABLE);
}

////////////////////////////////////////////////////////////////////////////////
// AccHideEvent
////////////////////////////////////////////////////////////////////////////////

AccHideEvent::AccHideEvent(LocalAccessible* aTarget, bool aNeedsShutdown)
    : AccMutationEvent(::nsIAccessibleEvent::EVENT_HIDE, aTarget),
      mNeedsShutdown(aNeedsShutdown) {
  mNextSibling = mAccessible->LocalNextSibling();
  mPrevSibling = mAccessible->LocalPrevSibling();
}

////////////////////////////////////////////////////////////////////////////////
// AccShowEvent
////////////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////////////
// AccTextSelChangeEvent
////////////////////////////////////////////////////////////////////////////////

AccTextSelChangeEvent::AccTextSelChangeEvent(HyperTextAccessible* aTarget,
                                             dom::Selection* aSelection,
                                             int32_t aReason,
                                             int32_t aGranularity)
    : AccEvent(nsIAccessibleEvent::EVENT_TEXT_SELECTION_CHANGED, aTarget,
               eAutoDetect, eCoalesceTextSelChange),
      mSel(aSelection),
      mReason(aReason),
      mGranularity(aGranularity) {}

AccTextSelChangeEvent::~AccTextSelChangeEvent() {}

bool AccTextSelChangeEvent::IsCaretMoveOnly() const {
  return mSel->RangeCount() == 1 && mSel->IsCollapsed() &&
         ((mReason & (nsISelectionListener::COLLAPSETOSTART_REASON |
                      nsISelectionListener::COLLAPSETOEND_REASON)) == 0);
}

void AccTextSelChangeEvent::SelectionRanges(
    nsTArray<TextRange>* aRanges) const {
  TextRange::TextRangesFromSelection(mSel, aRanges);
}

////////////////////////////////////////////////////////////////////////////////
// AccSelChangeEvent
////////////////////////////////////////////////////////////////////////////////

AccSelChangeEvent::AccSelChangeEvent(LocalAccessible* aWidget,
                                     LocalAccessible* aItem,
                                     SelChangeType aSelChangeType)
    : AccEvent(0, aItem, eAutoDetect, eCoalesceSelectionChange),
      mWidget(aWidget),
      mItem(aItem),
      mSelChangeType(aSelChangeType),
      mPreceedingCount(0),
      mPackedEvent(nullptr) {
  if (aSelChangeType == eSelectionAdd) {
    if (mWidget->GetSelectedItem(1)) {
      mEventType = nsIAccessibleEvent::EVENT_SELECTION_ADD;
    } else {
      mEventType = nsIAccessibleEvent::EVENT_SELECTION;
    }
  } else {
    mEventType = nsIAccessibleEvent::EVENT_SELECTION_REMOVE;
  }
}

already_AddRefed<nsIAccessibleEvent> a11y::MakeXPCEvent(AccEvent* aEvent) {
  DocAccessible* doc = aEvent->Document();
  LocalAccessible* acc = aEvent->GetAccessible();
  nsINode* node = acc->GetNode();
  bool fromUser = aEvent->IsFromUserInput();
  uint32_t type = aEvent->GetEventType();
  uint32_t eventGroup = aEvent->GetEventGroups();
  nsCOMPtr<nsIAccessibleEvent> xpEvent;

  if (eventGroup & (1 << AccEvent::eStateChangeEvent)) {
    AccStateChangeEvent* sc = downcast_accEvent(aEvent);
    bool extra = false;
    uint32_t state = nsAccUtils::To32States(sc->GetState(), &extra);
    xpEvent = new xpcAccStateChangeEvent(type, ToXPC(acc), ToXPCDocument(doc),
                                         node, fromUser, state, extra,
                                         sc->IsStateEnabled());
    return xpEvent.forget();
  }

  if (eventGroup & (1 << AccEvent::eTextChangeEvent)) {
    AccTextChangeEvent* tc = downcast_accEvent(aEvent);
    nsString text;
    tc->GetModifiedText(text);
    xpEvent = new xpcAccTextChangeEvent(
        type, ToXPC(acc), ToXPCDocument(doc), node, fromUser,
        tc->GetStartOffset(), tc->GetLength(), tc->IsTextInserted(), text);
    return xpEvent.forget();
  }

  if (eventGroup & (1 << AccEvent::eHideEvent)) {
    AccHideEvent* hideEvent = downcast_accEvent(aEvent);
    xpEvent = new xpcAccHideEvent(type, ToXPC(acc), ToXPCDocument(doc), node,
                                  fromUser, ToXPC(hideEvent->TargetParent()),
                                  ToXPC(hideEvent->TargetNextSibling()),
                                  ToXPC(hideEvent->TargetPrevSibling()));
    return xpEvent.forget();
  }

  if (eventGroup & (1 << AccEvent::eCaretMoveEvent)) {
    AccCaretMoveEvent* cm = downcast_accEvent(aEvent);
    xpEvent = new xpcAccCaretMoveEvent(
        type, ToXPC(acc), ToXPCDocument(doc), node, fromUser,
        cm->GetCaretOffset(), cm->IsSelectionCollapsed(), cm->IsAtEndOfLine(),
        cm->GetGranularity());
    return xpEvent.forget();
  }

  if (eventGroup & (1 << AccEvent::eTextSelChangeEvent)) {
    AccTextSelChangeEvent* tsc = downcast_accEvent(aEvent);
    AutoTArray<TextRange, 1> ranges;
    tsc->SelectionRanges(&ranges);

    nsCOMPtr<nsIMutableArray> xpcRanges =
        do_CreateInstance(NS_ARRAY_CONTRACTID);
    uint32_t len = ranges.Length();
    for (uint32_t idx = 0; idx < len; idx++) {
      xpcRanges->AppendElement(new xpcAccessibleTextRange(ranges[idx]));
    }

    xpEvent = new xpcAccTextSelectionChangeEvent(
        type, ToXPC(acc), ToXPCDocument(doc), node, fromUser, xpcRanges);
    return xpEvent.forget();
  }

  if (eventGroup & (1 << AccEvent::eObjectAttrChangedEvent)) {
    AccObjectAttrChangedEvent* oac = downcast_accEvent(aEvent);
    nsString attribute;
    oac->GetAttribute()->ToString(attribute);
    xpEvent = new xpcAccObjectAttributeChangedEvent(
        type, ToXPC(acc), ToXPCDocument(doc), node, fromUser, attribute);
    return xpEvent.forget();
  }

  if (eventGroup & (1 << AccEvent::eScrollingEvent)) {
    AccScrollingEvent* sa = downcast_accEvent(aEvent);
    xpEvent = new xpcAccScrollingEvent(
        type, ToXPC(acc), ToXPCDocument(doc), node, fromUser, sa->ScrollX(),
        sa->ScrollY(), sa->MaxScrollX(), sa->MaxScrollY());
    return xpEvent.forget();
  }

  if (eventGroup & (1 << AccEvent::eAnnouncementEvent)) {
    AccAnnouncementEvent* aa = downcast_accEvent(aEvent);
    xpEvent = new xpcAccAnnouncementEvent(type, ToXPC(acc), ToXPCDocument(doc),
                                          node, fromUser, aa->Announcement(),
                                          aa->Priority());
    return xpEvent.forget();
  }

  xpEvent =
      new xpcAccEvent(type, ToXPC(acc), ToXPCDocument(doc), node, fromUser);
  return xpEvent.forget();
}