gecko-dev/dom/events/TouchEvent.cpp

/* -*- 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 "mozilla/dom/Navigator.h"
#include "mozilla/dom/TouchEvent.h"
#include "mozilla/dom/Touch.h"
#include "mozilla/dom/TouchListBinding.h"
#include "mozilla/Preferences.h"
#include "mozilla/TouchEvents.h"
#include "nsContentUtils.h"
#include "nsIDocShell.h"
#include "mozilla/WidgetUtils.h"

namespace mozilla {

namespace dom {

/******************************************************************************
 * TouchList
 *****************************************************************************/

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(TouchList)
  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(TouchList, mParent, mPoints)

NS_IMPL_CYCLE_COLLECTING_ADDREF(TouchList)
NS_IMPL_CYCLE_COLLECTING_RELEASE(TouchList)

JSObject*
TouchList::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
{
  return TouchListBinding::Wrap(aCx, this, aGivenProto);
}

// static
bool
TouchList::PrefEnabled(JSContext* aCx, JSObject* aGlobal)
{
  return TouchEvent::PrefEnabled(aCx, aGlobal);
}

/******************************************************************************
 * TouchEvent
 *****************************************************************************/

TouchEvent::TouchEvent(EventTarget* aOwner,
                       nsPresContext* aPresContext,
                       WidgetTouchEvent* aEvent)
  : UIEvent(aOwner, aPresContext,
            aEvent ? aEvent :
                     new WidgetTouchEvent(false, eVoidEvent, nullptr))
{
  if (aEvent) {
    mEventIsInternal = false;

    for (uint32_t i = 0; i < aEvent->mTouches.Length(); ++i) {
      Touch* touch = aEvent->mTouches[i];
      touch->InitializePoints(mPresContext, aEvent);
    }
  } else {
    mEventIsInternal = true;
    mEvent->mTime = PR_Now();
  }
}

NS_IMPL_CYCLE_COLLECTION_INHERITED(TouchEvent, UIEvent,
                                   mTouches,
                                   mTargetTouches,
                                   mChangedTouches)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(TouchEvent)
NS_INTERFACE_MAP_END_INHERITING(UIEvent)

NS_IMPL_ADDREF_INHERITED(TouchEvent, UIEvent)
NS_IMPL_RELEASE_INHERITED(TouchEvent, UIEvent)

void
TouchEvent::InitTouchEvent(const nsAString& aType,
                           bool aCanBubble,
                           bool aCancelable,
                           nsGlobalWindow* aView,
                           int32_t aDetail,
                           bool aCtrlKey,
                           bool aAltKey,
                           bool aShiftKey,
                           bool aMetaKey,
                           TouchList* aTouches,
                           TouchList* aTargetTouches,
                           TouchList* aChangedTouches)
{
  NS_ENSURE_TRUE_VOID(!mEvent->mFlags.mIsBeingDispatched);

  UIEvent::InitUIEvent(aType, aCanBubble, aCancelable, aView, aDetail);
  mEvent->AsInputEvent()->InitBasicModifiers(aCtrlKey, aAltKey,
                                             aShiftKey, aMetaKey);
  mTouches = aTouches;
  mTargetTouches = aTargetTouches;
  mChangedTouches = aChangedTouches;
}

TouchList*
TouchEvent::Touches()
{
  if (!mTouches) {
    WidgetTouchEvent* touchEvent = mEvent->AsTouchEvent();
    if (mEvent->mMessage == eTouchEnd || mEvent->mMessage == eTouchCancel) {
      // for touchend events, remove any changed touches from mTouches
      WidgetTouchEvent::AutoTouchArray unchangedTouches;
      const WidgetTouchEvent::TouchArray& touches = touchEvent->mTouches;
      for (uint32_t i = 0; i < touches.Length(); ++i) {
        if (!touches[i]->mChanged) {
          unchangedTouches.AppendElement(touches[i]);
        }
      }
      mTouches = new TouchList(ToSupports(this), unchangedTouches);
    } else {
      mTouches = new TouchList(ToSupports(this), touchEvent->mTouches);
    }
  }
  return mTouches;
}

TouchList*
TouchEvent::TargetTouches()
{
  if (!mTargetTouches) {
    WidgetTouchEvent::AutoTouchArray targetTouches;
    WidgetTouchEvent* touchEvent = mEvent->AsTouchEvent();
    const WidgetTouchEvent::TouchArray& touches = touchEvent->mTouches;
    for (uint32_t i = 0; i < touches.Length(); ++i) {
      // for touchend/cancel events, don't append to the target list if this is a
      // touch that is ending
      if ((mEvent->mMessage != eTouchEnd && mEvent->mMessage != eTouchCancel) ||
          !touches[i]->mChanged) {
        if (touches[i]->mTarget == mEvent->mOriginalTarget) {
          targetTouches.AppendElement(touches[i]);
        }
      }
    }
    mTargetTouches = new TouchList(ToSupports(this), targetTouches);
  }
  return mTargetTouches;
}

TouchList*
TouchEvent::ChangedTouches()
{
  if (!mChangedTouches) {
    WidgetTouchEvent::AutoTouchArray changedTouches;
    WidgetTouchEvent* touchEvent = mEvent->AsTouchEvent();
    const WidgetTouchEvent::TouchArray& touches = touchEvent->mTouches;
    for (uint32_t i = 0; i < touches.Length(); ++i) {
      if (touches[i]->mChanged) {
        changedTouches.AppendElement(touches[i]);
      }
    }
    mChangedTouches = new TouchList(ToSupports(this), changedTouches);
  }
  return mChangedTouches;
}

// static
bool
TouchEvent::PrefEnabled(JSContext* aCx, JSObject* aGlobal)
{
  nsIDocShell* docShell = nullptr;
  if (aGlobal) {
    nsGlobalWindow* win = xpc::WindowOrNull(aGlobal);
    if (win) {
      docShell = win->GetDocShell();
    }
  }
  return PrefEnabled(docShell);
}

// static
bool
TouchEvent::PrefEnabled(nsIDocShell* aDocShell)
{
  static bool sPrefCached = false;
  static int32_t sPrefCacheValue = 0;

  uint32_t touchEventsOverride = nsIDocShell::TOUCHEVENTS_OVERRIDE_NONE;
  if (aDocShell) {
    aDocShell->GetTouchEventsOverride(&touchEventsOverride);
  }

  if (!sPrefCached) {
    sPrefCached = true;
    Preferences::AddIntVarCache(&sPrefCacheValue, "dom.w3c_touch_events.enabled");
  }

  bool enabled = false;
  if (touchEventsOverride == nsIDocShell::TOUCHEVENTS_OVERRIDE_ENABLED) {
    enabled = true;
  } else if (touchEventsOverride == nsIDocShell::TOUCHEVENTS_OVERRIDE_DISABLED) {
    enabled = false;
  } else {
    if (sPrefCacheValue == 2) {
#if defined(MOZ_B2G) || defined(MOZ_WIDGET_ANDROID)
      // Touch support is always enabled on B2G and android.
      enabled = true;
#elif defined(XP_WIN) || MOZ_WIDGET_GTK == 3
      static bool sDidCheckTouchDeviceSupport = false;
      static bool sIsTouchDeviceSupportPresent = false;
      // On Windows and GTK3 we auto-detect based on device support.
      if (!sDidCheckTouchDeviceSupport) {
        sDidCheckTouchDeviceSupport = true;
        sIsTouchDeviceSupportPresent = WidgetUtils::IsTouchDeviceSupportPresent();
        // But touch events are only actually supported if APZ is enabled. If
        // APZ is disabled globally, we can check that once and incorporate that
        // into the cached state. If APZ is enabled, we need to further check
        // based on the widget, which we do below (and don't cache that result).
        sIsTouchDeviceSupportPresent &= gfxPlatform::AsyncPanZoomEnabled();
      }
      enabled = sIsTouchDeviceSupportPresent;
      if (enabled && aDocShell) {
        // APZ might be disabled on this particular widget, in which case
        // TouchEvent support will also be disabled. Try to detect that.
        nsPresContext* pc = nullptr;
        aDocShell->GetPresContext(&pc);
        if (pc && pc->GetRootWidget()) {
          enabled &= pc->GetRootWidget()->AsyncPanZoomEnabled();
        }
      }
#else
      enabled = false;
#endif
    } else {
      enabled = !!sPrefCacheValue;
    }
  }

  if (enabled) {
    nsContentUtils::InitializeTouchEventTable();
  }
  return enabled;
}

// static
already_AddRefed<Event>
TouchEvent::Constructor(const GlobalObject& aGlobal,
                        const nsAString& aType,
                        const TouchEventInit& aParam,
                        ErrorResult& aRv)
{
  nsCOMPtr<EventTarget> t = do_QueryInterface(aGlobal.GetAsSupports());
  RefPtr<TouchEvent> e = new TouchEvent(t, nullptr, nullptr);
  bool trusted = e->Init(t);
  RefPtr<TouchList> touches = e->CopyTouches(aParam.mTouches);
  RefPtr<TouchList> targetTouches = e->CopyTouches(aParam.mTargetTouches);
  RefPtr<TouchList> changedTouches = e->CopyTouches(aParam.mChangedTouches);
  e->InitTouchEvent(aType, aParam.mBubbles, aParam.mCancelable, aParam.mView,
                    aParam.mDetail, aParam.mCtrlKey, aParam.mAltKey,
                    aParam.mShiftKey, aParam.mMetaKey, touches, targetTouches,
                    changedTouches);
  e->SetTrusted(trusted);
  e->SetComposed(aParam.mComposed);
  return e.forget();
}


already_AddRefed<TouchList>
TouchEvent::CopyTouches(const Sequence<OwningNonNull<Touch>>& aTouches)
{
  RefPtr<TouchList> list = new TouchList(GetParentObject());
  size_t len = aTouches.Length();
  for (size_t i = 0; i < len; ++i) {
    list->Append(aTouches[i]);
  }
  return list.forget();
}

bool
TouchEvent::AltKey()
{
  return mEvent->AsTouchEvent()->IsAlt();
}

bool
TouchEvent::MetaKey()
{
  return mEvent->AsTouchEvent()->IsMeta();
}

bool
TouchEvent::CtrlKey()
{
  return mEvent->AsTouchEvent()->IsControl();
}

bool
TouchEvent::ShiftKey()
{
  return mEvent->AsTouchEvent()->IsShift();
}

} // namespace dom
} // namespace mozilla

using namespace mozilla;
using namespace mozilla::dom;

already_AddRefed<TouchEvent>
NS_NewDOMTouchEvent(EventTarget* aOwner,
                    nsPresContext* aPresContext,
                    WidgetTouchEvent* aEvent)
{
  RefPtr<TouchEvent> it = new TouchEvent(aOwner, aPresContext, aEvent);
  return it.forget();
}