widget/BasicEvents.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef mozilla_BasicEvents_h__
   7 #define mozilla_BasicEvents_h__
   8
   9 #include <stdint.h>
  10 #include <type_traits>
  11
  12 #include "mozilla/EventForwards.h"
  13 #include "mozilla/TimeStamp.h"
  14 #include "mozilla/dom/EventTarget.h"
  15 #include "mozilla/layers/LayersTypes.h"
  16 #include "nsCOMPtr.h"
  17 #include "nsAtom.h"
  18 #include "nsISupportsImpl.h"
  19 #include "nsIWidget.h"
  20 #include "nsString.h"
  21 #include "Units.h"
  22
  23 #ifdef DEBUG
  24 #  include "nsXULAppAPI.h"
  25 #endif  // #ifdef DEBUG
  26
  27 class nsIPrincipal;
  28
  29 namespace IPC {
  30 template <typename T>
  31 struct ParamTraits;
  32 }  // namespace IPC
  33
  34 namespace mozilla {
  35
  36 class EventTargetChainItem;
  37
  38 enum class CrossProcessForwarding {
  39   // eStop prevents the event to be sent to remote process.
  40   eStop,
  41   // eAllow keeps current state of the event whether it's sent to remote
  42   // process.  In other words, eAllow does NOT mean that making the event
  43   // sent to remote process when IsCrossProcessForwardingStopped() returns
  44   // true.
  45   eAllow,
  46 };
  47
  48 /******************************************************************************
  49  * mozilla::BaseEventFlags
  50  *
  51  * BaseEventFlags must be a POD struct for safe to use memcpy (including
  52  * in ParamTraits<BaseEventFlags>).  So don't make virtual methods, constructor,
  53  * destructor and operators.
  54  * This is necessary for VC which is NOT C++0x compiler.
  55  ******************************************************************************/
  56
  57 struct BaseEventFlags {
  58  public:
  59   // If mIsTrusted is true, the event is a trusted event.  Otherwise, it's
  60   // an untrusted event.
  61   bool mIsTrusted : 1;
  62   // If mInBubblingPhase is true, the event is in bubbling phase or target
  63   // phase.
  64   bool mInBubblingPhase : 1;
  65   // If mInCapturePhase is true, the event is in capture phase or target phase.
  66   bool mInCapturePhase : 1;
  67   // If mInTargetPhase is true, the event is in target phase.
  68   bool mInTargetPhase : 1;
  69   // If mInSystemGroup is true, the event is being dispatched in system group.
  70   bool mInSystemGroup : 1;
  71   // If mCancelable is true, the event can be consumed.  I.e., calling
  72   // dom::Event::PreventDefault() can prevent the default action.
  73   bool mCancelable : 1;
  74   // If mBubbles is true, the event can bubble.  Otherwise, cannot be handled
  75   // in bubbling phase.
  76   bool mBubbles : 1;
  77   // If mPropagationStopped is true, dom::Event::StopPropagation() or
  78   // dom::Event::StopImmediatePropagation() has been called.
  79   bool mPropagationStopped : 1;
  80   // If mImmediatePropagationStopped is true,
  81   // dom::Event::StopImmediatePropagation() has been called.
  82   // Note that mPropagationStopped must be true when this is true.
  83   bool mImmediatePropagationStopped : 1;
  84   // If mDefaultPrevented is true, the event has been consumed.
  85   // E.g., dom::Event::PreventDefault() has been called or
  86   // the default action has been performed.
  87   bool mDefaultPrevented : 1;
  88   // If mDefaultPreventedByContent is true, the event has been
  89   // consumed by content.
  90   // Note that mDefaultPrevented must be true when this is true.
  91   bool mDefaultPreventedByContent : 1;
  92   // If mDefaultPreventedByChrome is true, the event has been
  93   // consumed by chrome.
  94   // Note that mDefaultPrevented must be true when this is true.
  95   bool mDefaultPreventedByChrome : 1;
  96   // mMultipleActionsPrevented may be used when default handling don't want to
  97   // be prevented, but only one of the event targets should handle the event.
  98   // For example, when a <label> element is in another <label> element and
  99   // the first <label> element is clicked, that one may set this true.
 100   // Then, the second <label> element won't handle the event.
 101   bool mMultipleActionsPrevented : 1;
 102   // Similar to above but expected to be used during PreHandleEvent phase.
 103   bool mMultiplePreActionsPrevented : 1;
 104   // If mIsBeingDispatched is true, the DOM event created from the event is
 105   // dispatching into the DOM tree and not completed.
 106   bool mIsBeingDispatched : 1;
 107   // If mDispatchedAtLeastOnce is true, the event has been dispatched
 108   // as a DOM event and the dispatch has been completed in the process.
 109   // So, this is false even if the event has already been dispatched
 110   // in another process.
 111   bool mDispatchedAtLeastOnce : 1;
 112   // If mIsSynthesizedForTests is true, the event has been synthesized for
 113   // automated tests or something hacky approach of an add-on.
 114   bool mIsSynthesizedForTests : 1;
 115   // If mExceptionWasRaised is true, one of the event handlers has raised an
 116   // exception.
 117   bool mExceptionWasRaised : 1;
 118   // If mRetargetToNonNativeAnonymous is true and the target is in a non-native
 119   // native anonymous subtree, the event target is set to mOriginalTarget.
 120   bool mRetargetToNonNativeAnonymous : 1;
 121   // If mNoContentDispatch is true, the event is never dispatched to the
 122   // event handlers which are added to the contents, onfoo attributes and
 123   // properties.  Note that this flag is ignored when
 124   // EventChainPreVisitor::mForceContentDispatch is set true.  For exapmle,
 125   // window and document object sets it true.  Therefore, web applications
 126   // can handle the event if they add event listeners to the window or the
 127   // document.
 128   // XXX This is an ancient and broken feature, don't use this for new bug
 129   //     as far as possible.
 130   bool mNoContentDispatch : 1;
 131   // If mOnlyChromeDispatch is true, the event is dispatched to only chrome.
 132   bool mOnlyChromeDispatch : 1;
 133   // Indicates if the key combination is reserved by chrome.  This is set by
 134   // MarkAsReservedByChrome().
 135   bool mIsReservedByChrome : 1;
 136   // If mOnlySystemGroupDispatchInContent is true, event listeners added to
 137   // the default group for non-chrome EventTarget won't be called.
 138   // Be aware, if this is true, EventDispatcher needs to check if each event
 139   // listener is added to chrome node, so, don't set this to true for the
 140   // events which are fired a lot of times like eMouseMove.
 141   bool mOnlySystemGroupDispatchInContent : 1;
 142   // If mOnlySystemGroupDispatch is true, the event will be dispatched only to
 143   // event listeners added in the system group.
 144   bool mOnlySystemGroupDispatch : 1;
 145   // The event's action will be handled by APZ. The main thread should not
 146   // perform its associated action.
 147   bool mHandledByAPZ : 1;
 148   // True if the event is currently being handled by an event listener that
 149   // was registered as a passive listener.
 150   bool mInPassiveListener : 1;
 151   // If mComposed is true, the event fired by nodes in shadow DOM can cross the
 152   // boundary of shadow DOM and light DOM.
 153   bool mComposed : 1;
 154   // Similar to mComposed. Set it to true to allow events cross the boundary
 155   // between native non-anonymous content and native anonymouse content
 156   bool mComposedInNativeAnonymousContent : 1;
 157   // Set to true for events which are suppressed or delayed so that later a
 158   // DelayedEvent of it is dispatched. This is used when parent side process
 159   // the key event after content side, and may drop the event if the event
 160   // was suppressed or delayed in contents side.
 161   // It is also set to true for the events (in a DelayedInputEvent), which will
 162   // be dispatched afterwards.
 163   bool mIsSuppressedOrDelayed : 1;
 164   // Certain mouse events can be marked as positionless to return 0 from
 165   // coordinate related getters.
 166   bool mIsPositionless : 1;
 167
 168   // Flags managing state of propagation between processes.
 169   // Note the the following flags shouldn't be referred directly.  Use utility
 170   // methods instead.
 171
 172   // If mNoRemoteProcessDispatch is true, the event is not allowed to be sent
 173   // to remote process.
 174   bool mNoRemoteProcessDispatch : 1;
 175   // If mWantReplyFromContentProcess is true, the event will be redispatched
 176   // in the parent process after the content process has handled it. Useful
 177   // for when the parent process need the know first how the event was used
 178   // by content before handling it itself.
 179   bool mWantReplyFromContentProcess : 1;
 180   // If mPostedToRemoteProcess is true, the event has been posted to the
 181   // remote process (but it's not handled yet if it's not a duplicated event
 182   // instance).
 183   bool mPostedToRemoteProcess : 1;
 184   // If mCameFromAnotherProcess is true, the event came from another process.
 185   bool mCameFromAnotherProcess : 1;
 186
 187   /**
 188    * Helper methods for methods of DOM Event.
 189    */
 190   inline void StopPropagation() { mPropagationStopped = true; }
 191   inline void StopImmediatePropagation() {
 192     StopPropagation();
 193     mImmediatePropagationStopped = true;
 194   }
 195   inline void PreventDefault(bool aCalledByDefaultHandler = true) {
 196     if (!mCancelable) {
 197       return;
 198     }
 199     mDefaultPrevented = true;
 200     // Note that even if preventDefault() has already been called by chrome,
 201     // a call of preventDefault() by content needs to overwrite
 202     // mDefaultPreventedByContent to true because in such case, defaultPrevented
 203     // must be true when web apps check it after they call preventDefault().
 204     if (aCalledByDefaultHandler) {
 205       StopCrossProcessForwarding();
 206       mDefaultPreventedByChrome = true;
 207     } else {
 208       mDefaultPreventedByContent = true;
 209     }
 210   }
 211   // This should be used only before dispatching events into the DOM tree.
 212   inline void PreventDefaultBeforeDispatch(
 213       CrossProcessForwarding aCrossProcessForwarding) {
 214     if (!mCancelable) {
 215       return;
 216     }
 217     mDefaultPrevented = true;
 218     if (aCrossProcessForwarding == CrossProcessForwarding::eStop) {
 219       StopCrossProcessForwarding();
 220     }
 221   }
 222   inline bool DefaultPrevented() const { return mDefaultPrevented; }
 223   inline bool DefaultPreventedByContent() const {
 224     MOZ_ASSERT(!mDefaultPreventedByContent || DefaultPrevented());
 225     return mDefaultPreventedByContent;
 226   }
 227   inline bool IsTrusted() const { return mIsTrusted; }
 228   inline bool PropagationStopped() const { return mPropagationStopped; }
 229
 230   // Helper methods to access flags managing state of propagation between
 231   // processes.
 232
 233   /**
 234    * Prevent to be dispatched to remote process.
 235    */
 236   inline void StopCrossProcessForwarding() {
 237     MOZ_ASSERT(!mPostedToRemoteProcess);
 238     mNoRemoteProcessDispatch = true;
 239     mWantReplyFromContentProcess = false;
 240   }
 241   /**
 242    * Return true if the event shouldn't be dispatched to remote process.
 243    */
 244   inline bool IsCrossProcessForwardingStopped() const {
 245     return mNoRemoteProcessDispatch;
 246   }
 247   /**
 248    * Mark the event as waiting reply from remote process.
 249    * If the caller needs to win other keyboard event handlers in chrome,
 250    * the caller should call StopPropagation() too.
 251    * Otherwise, if the caller just needs to know if the event is consumed by
 252    * either content or chrome, it should just call this because the event
 253    * may be reserved by chrome and it needs to be dispatched into the DOM
 254    * tree in chrome for checking if it's reserved before being sent to any
 255    * remote processes.
 256    */
 257   inline void MarkAsWaitingReplyFromRemoteProcess() {
 258     MOZ_ASSERT(!mPostedToRemoteProcess);
 259     mNoRemoteProcessDispatch = false;
 260     mWantReplyFromContentProcess = true;
 261   }
 262   /**
 263    * Reset "waiting reply from remote process" state.  This is useful when
 264    * you dispatch a copy of an event coming from different process.
 265    */
 266   inline void ResetWaitingReplyFromRemoteProcessState() {
 267     if (IsWaitingReplyFromRemoteProcess()) {
 268       // FYI: mWantReplyFromContentProcess is also used for indicating
 269       //      "handled in remote process" state.  Therefore, only when
 270       //      IsWaitingReplyFromRemoteProcess() returns true, this should
 271       //      reset the flag.
 272       mWantReplyFromContentProcess = false;
 273     }
 274   }
 275   /**
 276    * Return true if the event handler should wait reply event.  I.e., if this
 277    * returns true, any event handler should do nothing with the event.
 278    */
 279   inline bool IsWaitingReplyFromRemoteProcess() const {
 280     return !mNoRemoteProcessDispatch && mWantReplyFromContentProcess;
 281   }
 282   /**
 283    * Mark the event as already handled in the remote process.  This should be
 284    * called when initializing reply events.
 285    */
 286   inline void MarkAsHandledInRemoteProcess() {
 287     mNoRemoteProcessDispatch = true;
 288     mWantReplyFromContentProcess = true;
 289     mPostedToRemoteProcess = false;
 290   }
 291   /**
 292    * Return true if the event has already been handled in the remote process.
 293    */
 294   inline bool IsHandledInRemoteProcess() const {
 295     return mNoRemoteProcessDispatch && mWantReplyFromContentProcess;
 296   }
 297   /**
 298    * Return true if the event should be sent back to its parent process.
 299    */
 300   inline bool WantReplyFromContentProcess() const {
 301     MOZ_ASSERT(!XRE_IsParentProcess());
 302     return IsWaitingReplyFromRemoteProcess();
 303   }
 304   /**
 305    * Mark the event has already posted to a remote process.
 306    */
 307   inline void MarkAsPostedToRemoteProcess() {
 308     MOZ_ASSERT(!IsCrossProcessForwardingStopped());
 309     mPostedToRemoteProcess = true;
 310   }
 311   /**
 312    * Reset the cross process dispatching state.  This should be used when a
 313    * process receives the event because the state is in the sender.
 314    */
 315   inline void ResetCrossProcessDispatchingState() {
 316     MOZ_ASSERT(!IsCrossProcessForwardingStopped());
 317     mPostedToRemoteProcess = false;
 318     // Ignore propagation state in the remote process if it's marked as
 319     // "waiting reply from remote process" because the process needs to
 320     // stop propagation in the process until receiving a reply event.
 321     // Note that the propagation stopped flag is important for the reply event
 322     // handler in the main process because it's used for making whether it's
 323     // ignored by the remote process or not.
 324     if (!XRE_IsParentProcess() && IsWaitingReplyFromRemoteProcess()) {
 325       mPropagationStopped = mImmediatePropagationStopped = false;
 326     }
 327     // mDispatchedAtLeastOnce indicates the state in current process.
 328     mDispatchedAtLeastOnce = false;
 329   }
 330   /**
 331    * Return true if the event has been posted to a remote process.
 332    * Note that MarkAsPostedToRemoteProcess() is called by
 333    * ParamTraits<mozilla::WidgetEvent>.  Therefore, it *might* be possible
 334    * that posting the event failed even if this returns true.  But that must
 335    * really rare.  If that'd be problem for you, you should unmark this in
 336    * BrowserParent or somewhere.
 337    */
 338   inline bool HasBeenPostedToRemoteProcess() const {
 339     return mPostedToRemoteProcess;
 340   }
 341   /**
 342    * Return true if the event came from another process.
 343    */
 344   inline bool CameFromAnotherProcess() const { return mCameFromAnotherProcess; }
 345   /**
 346    * Mark the event as coming from another process.
 347    */
 348   inline void MarkAsComingFromAnotherProcess() {
 349     mCameFromAnotherProcess = true;
 350   }
 351   /**
 352    * Mark the event is reserved by chrome.  I.e., shouldn't be dispatched to
 353    * content because it shouldn't be cancelable.
 354    */
 355   inline void MarkAsReservedByChrome() {
 356     MOZ_ASSERT(!mPostedToRemoteProcess);
 357     mIsReservedByChrome = true;
 358     // For reserved commands (such as Open New Tab), we don't need to wait for
 359     // the content to answer, neither to give a chance for content to override
 360     // its behavior.
 361     StopCrossProcessForwarding();
 362     // If the event is reserved by chrome, we shouldn't expose the event to
 363     // web contents because such events shouldn't be cancelable.  So, it's not
 364     // good behavior to fire such events but to ignore the defaultPrevented
 365     // attribute value in chrome.
 366     mOnlySystemGroupDispatchInContent = true;
 367   }
 368   /**
 369    * Return true if the event is reserved by chrome.
 370    */
 371   inline bool IsReservedByChrome() const {
 372     MOZ_ASSERT(!mIsReservedByChrome || (IsCrossProcessForwardingStopped() &&
 373                                         mOnlySystemGroupDispatchInContent));
 374     return mIsReservedByChrome;
 375   }
 376
 377   inline void Clear() { SetRawFlags(0); }
 378   // Get if either the instance's bit or the aOther's bit is true, the
 379   // instance's bit becomes true.  In other words, this works like:
 380   // eventFlags |= aOther;
 381   inline void Union(const BaseEventFlags& aOther) {
 382     RawFlags rawFlags = GetRawFlags() | aOther.GetRawFlags();
 383     SetRawFlags(rawFlags);
 384   }
 385
 386  private:
 387   typedef uint64_t RawFlags;
 388
 389   inline void SetRawFlags(RawFlags aRawFlags) {
 390     static_assert(sizeof(BaseEventFlags) <= sizeof(RawFlags),
 391                   "mozilla::EventFlags must not be bigger than the RawFlags");
 392     memcpy(this, &aRawFlags, sizeof(BaseEventFlags));
 393   }
 394   inline RawFlags GetRawFlags() const {
 395     RawFlags result = 0;
 396     memcpy(&result, this, sizeof(BaseEventFlags));
 397     return result;
 398   }
 399 };
 400
 401 /******************************************************************************
 402  * mozilla::EventFlags
 403  ******************************************************************************/
 404
 405 struct EventFlags : public BaseEventFlags {
 406   EventFlags() { Clear(); }
 407 };
 408
 409 /******************************************************************************
 410  * mozilla::WidgetEventTime
 411  ******************************************************************************/
 412
 413 class WidgetEventTime {
 414  public:
 415   // Timestamp when the message was created.
 416   TimeStamp mTimeStamp;
 417
 418   WidgetEventTime() : mTimeStamp(TimeStamp::Now()) {}
 419
 420   explicit WidgetEventTime(const WidgetEventTime* aTime)
 421       : mTimeStamp(aTime ? aTime->mTimeStamp : TimeStamp::Now()) {
 422     MOZ_ASSERT(aTime != this);
 423     MOZ_ASSERT_IF(aTime, !aTime->mTimeStamp.IsNull());
 424   }
 425
 426   explicit WidgetEventTime(TimeStamp aTimeStamp) : mTimeStamp(aTimeStamp) {}
 427
 428   void AssignEventTime(const WidgetEventTime& aOther) {
 429     mTimeStamp = aOther.mTimeStamp;
 430   }
 431 };
 432
 433 /******************************************************************************
 434  * mozilla::WidgetEvent
 435  ******************************************************************************/
 436
 437 class WidgetEvent : public WidgetEventTime {
 438  private:
 439   void SetDefaultCancelableAndBubbles() {
 440     switch (mClass) {
 441       case eEditorInputEventClass:
 442         mFlags.mCancelable = false;
 443         mFlags.mBubbles = mFlags.mIsTrusted;
 444         break;
 445       case eMouseEventClass:
 446         mFlags.mCancelable =
 447             (mMessage != eMouseEnter && mMessage != eMouseLeave);
 448         mFlags.mBubbles = (mMessage != eMouseEnter && mMessage != eMouseLeave);
 449         break;
 450       case ePointerEventClass:
 451         mFlags.mCancelable =
 452             (mMessage != ePointerEnter && mMessage != ePointerLeave &&
 453              mMessage != ePointerCancel && mMessage != ePointerGotCapture &&
 454              mMessage != ePointerLostCapture);
 455         mFlags.mBubbles =
 456             (mMessage != ePointerEnter && mMessage != ePointerLeave);
 457         break;
 458       case eDragEventClass:
 459         mFlags.mCancelable = (mMessage != eDragExit && mMessage != eDragLeave &&
 460                               mMessage != eDragEnd);
 461         mFlags.mBubbles = true;
 462         break;
 463       case eSMILTimeEventClass:
 464         mFlags.mCancelable = false;
 465         mFlags.mBubbles = false;
 466         break;
 467       case eTransitionEventClass:
 468       case eAnimationEventClass:
 469         mFlags.mCancelable = false;
 470         mFlags.mBubbles = true;
 471         break;
 472       case eCompositionEventClass:
 473         // XXX compositionstart is cancelable in draft of DOM3 Events.
 474         //     However, it doesn't make sense for us, we cannot cancel
 475         //     composition when we send compositionstart event.
 476         mFlags.mCancelable = false;
 477         mFlags.mBubbles = true;
 478         break;
 479       default:
 480         if (mMessage == eResize || mMessage == eMozVisualResize ||
 481             mMessage == eMozVisualScroll || mMessage == eEditorInput ||
 482             mMessage == eFormSelect) {
 483           mFlags.mCancelable = false;
 484         } else {
 485           mFlags.mCancelable = true;
 486         }
 487         mFlags.mBubbles = true;
 488         break;
 489     }
 490   }
 491
 492  protected:
 493   WidgetEvent(bool aIsTrusted, EventMessage aMessage,
 494               EventClassID aEventClassID,
 495               const WidgetEventTime* aTime = nullptr)
 496       : WidgetEventTime(aTime),
 497         mClass(aEventClassID),
 498         mMessage(aMessage),
 499         mRefPoint(0, 0),
 500         mLastRefPoint(0, 0),
 501         mFocusSequenceNumber(0),
 502         mSpecifiedEventType(nullptr),
 503         mPath(nullptr),
 504         mLayersId(layers::LayersId{0}) {
 505     MOZ_COUNT_CTOR(WidgetEvent);
 506     mFlags.Clear();
 507     mFlags.mIsTrusted = aIsTrusted;
 508     SetDefaultCancelableAndBubbles();
 509     SetDefaultComposed();
 510     SetDefaultComposedInNativeAnonymousContent();
 511   }
 512
 513   WidgetEvent() : WidgetEventTime(), mPath(nullptr) {
 514     MOZ_COUNT_CTOR(WidgetEvent);
 515   }
 516
 517  public:
 518   WidgetEvent(bool aIsTrusted, EventMessage aMessage,
 519               const WidgetEventTime* aTime = nullptr)
 520       : WidgetEvent(aIsTrusted, aMessage, eBasicEventClass, aTime) {}
 521
 522   MOZ_COUNTED_DTOR_VIRTUAL(WidgetEvent)
 523
 524   WidgetEvent(const WidgetEvent& aOther) : WidgetEventTime() {
 525     MOZ_COUNT_CTOR(WidgetEvent);
 526     *this = aOther;
 527   }
 528   WidgetEvent& operator=(const WidgetEvent& aOther) = default;
 529
 530   WidgetEvent(WidgetEvent&& aOther)
 531       : WidgetEventTime(std::move(aOther)),
 532         mClass(aOther.mClass),
 533         mMessage(aOther.mMessage),
 534         mRefPoint(std::move(aOther.mRefPoint)),
 535         mLastRefPoint(std::move(aOther.mLastRefPoint)),
 536         mFocusSequenceNumber(aOther.mFocusSequenceNumber),
 537         mFlags(std::move(aOther.mFlags)),
 538         mSpecifiedEventType(std::move(aOther.mSpecifiedEventType)),
 539         mSpecifiedEventTypeString(std::move(aOther.mSpecifiedEventTypeString)),
 540         mTarget(std::move(aOther.mTarget)),
 541         mCurrentTarget(std::move(aOther.mCurrentTarget)),
 542         mOriginalTarget(std::move(aOther.mOriginalTarget)),
 543         mRelatedTarget(std::move(aOther.mRelatedTarget)),
 544         mOriginalRelatedTarget(std::move(aOther.mOriginalRelatedTarget)),
 545         mPath(std::move(aOther.mPath)) {
 546     MOZ_COUNT_CTOR(WidgetEvent);
 547   }
 548   WidgetEvent& operator=(WidgetEvent&& aOther) = default;
 549
 550   virtual WidgetEvent* Duplicate() const {
 551     MOZ_ASSERT(mClass == eBasicEventClass,
 552                "Duplicate() must be overridden by sub class");
 553     WidgetEvent* result = new WidgetEvent(false, mMessage, this);
 554     result->AssignEventData(*this, true);
 555     result->mFlags = mFlags;
 556     return result;
 557   }
 558
 559   EventClassID mClass;
 560   EventMessage mMessage;
 561   // Relative to the widget of the event, or if there is no widget then it is
 562   // in screen coordinates. Not modified by layout code.
 563   // This is in visual coordinates, i.e. the correct RelativeTo value that
 564   // expresses what this is relative to is `{viewportFrame, Visual}`, where
 565   // `viewportFrame` is the viewport frame of the widget's root document.
 566   LayoutDeviceIntPoint mRefPoint;
 567   // The previous mRefPoint, if known, used to calculate mouse movement deltas.
 568   LayoutDeviceIntPoint mLastRefPoint;
 569   // The sequence number of the last potentially focus changing event handled
 570   // by APZ. This is used to track when that event has been processed by
 571   // content, and focus can be reconfirmed for async keyboard scrolling.
 572   uint64_t mFocusSequenceNumber;
 573   // See BaseEventFlags definition for the detail.
 574   BaseEventFlags mFlags;
 575
 576   // If JS creates an event with unknown event type or known event type but
 577   // for different event interface, the event type is stored to this.
 578   // NOTE: This is always used if the instance is a WidgetCommandEvent instance
 579   //       or "input" event is dispatched with dom::Event class.
 580   RefPtr<nsAtom> mSpecifiedEventType;
 581
 582   // nsAtom isn't available on non-main thread due to unsafe.  Therefore,
 583   // mSpecifiedEventTypeString is used instead of mSpecifiedEventType if
 584   // the event is created in non-main thread.
 585   nsString mSpecifiedEventTypeString;
 586
 587   // Event targets, needed by DOM Events
 588   // Note that when you need event target for DOM event, you should use
 589   // Get*DOMEventTarget() instead of accessing these members directly.
 590   nsCOMPtr<dom::EventTarget> mTarget;
 591   nsCOMPtr<dom::EventTarget> mCurrentTarget;
 592   nsCOMPtr<dom::EventTarget> mOriginalTarget;
 593
 594   /// The possible related target
 595   nsCOMPtr<dom::EventTarget> mRelatedTarget;
 596   nsCOMPtr<dom::EventTarget> mOriginalRelatedTarget;
 597
 598   nsTArray<EventTargetChainItem>* mPath;
 599
 600   // The LayersId of the content process that this event should be
 601   // dispatched to. This field is only used in the chrome process
 602   // and doesn't get remoted to child processes.
 603   layers::LayersId mLayersId;
 604
 605   dom::EventTarget* GetDOMEventTarget() const;
 606   dom::EventTarget* GetCurrentDOMEventTarget() const;
 607   dom::EventTarget* GetOriginalDOMEventTarget() const;
 608
 609   void AssignEventData(const WidgetEvent& aEvent, bool aCopyTargets) {
 610     // mClass should be initialized with the constructor.
 611     // mMessage should be initialized with the constructor.
 612     mRefPoint = aEvent.mRefPoint;
 613     // mLastRefPoint doesn't need to be copied.
 614     mFocusSequenceNumber = aEvent.mFocusSequenceNumber;
 615     // mLayersId intentionally not copied, since it's not used within content
 616     AssignEventTime(aEvent);
 617     // mFlags should be copied manually if it's necessary.
 618     mSpecifiedEventType = aEvent.mSpecifiedEventType;
 619     // mSpecifiedEventTypeString should be copied manually if it's necessary.
 620     mTarget = aCopyTargets ? aEvent.mTarget : nullptr;
 621     mCurrentTarget = aCopyTargets ? aEvent.mCurrentTarget : nullptr;
 622     mOriginalTarget = aCopyTargets ? aEvent.mOriginalTarget : nullptr;
 623     mRelatedTarget = aCopyTargets ? aEvent.mRelatedTarget : nullptr;
 624     mOriginalRelatedTarget =
 625         aCopyTargets ? aEvent.mOriginalRelatedTarget : nullptr;
 626   }
 627
 628   /**
 629    * Helper methods for methods of DOM Event.
 630    */
 631   void StopPropagation() { mFlags.StopPropagation(); }
 632   void StopImmediatePropagation() { mFlags.StopImmediatePropagation(); }
 633   void PreventDefault(bool aCalledByDefaultHandler = true,
 634                       nsIPrincipal* aPrincipal = nullptr);
 635
 636   void PreventDefaultBeforeDispatch(
 637       CrossProcessForwarding aCrossProcessForwarding) {
 638     mFlags.PreventDefaultBeforeDispatch(aCrossProcessForwarding);
 639   }
 640   bool DefaultPrevented() const { return mFlags.DefaultPrevented(); }
 641   bool DefaultPreventedByContent() const {
 642     return mFlags.DefaultPreventedByContent();
 643   }
 644   bool IsTrusted() const { return mFlags.IsTrusted(); }
 645   bool PropagationStopped() const { return mFlags.PropagationStopped(); }
 646
 647   /**
 648    * Prevent to be dispatched to remote process.
 649    */
 650   inline void StopCrossProcessForwarding() {
 651     mFlags.StopCrossProcessForwarding();
 652   }
 653   /**
 654    * Return true if the event shouldn't be dispatched to remote process.
 655    */
 656   inline bool IsCrossProcessForwardingStopped() const {
 657     return mFlags.IsCrossProcessForwardingStopped();
 658   }
 659   /**
 660    * Mark the event as waiting reply from remote process.
 661    * Note that this also stops immediate propagation in current process.
 662    */
 663   inline void MarkAsWaitingReplyFromRemoteProcess() {
 664     mFlags.MarkAsWaitingReplyFromRemoteProcess();
 665   }
 666   /**
 667    * Reset "waiting reply from remote process" state.  This is useful when
 668    * you dispatch a copy of an event coming from different process.
 669    */
 670   inline void ResetWaitingReplyFromRemoteProcessState() {
 671     mFlags.ResetWaitingReplyFromRemoteProcessState();
 672   }
 673   /**
 674    * Return true if the event handler should wait reply event.  I.e., if this
 675    * returns true, any event handler should do nothing with the event.
 676    */
 677   inline bool IsWaitingReplyFromRemoteProcess() const {
 678     return mFlags.IsWaitingReplyFromRemoteProcess();
 679   }
 680   /**
 681    * Mark the event as already handled in the remote process.  This should be
 682    * called when initializing reply events.
 683    */
 684   inline void MarkAsHandledInRemoteProcess() {
 685     mFlags.MarkAsHandledInRemoteProcess();
 686   }
 687   /**
 688    * Return true if the event has already been handled in the remote process.
 689    * I.e., if this returns true, the event is a reply event.
 690    */
 691   inline bool IsHandledInRemoteProcess() const {
 692     return mFlags.IsHandledInRemoteProcess();
 693   }
 694   /**
 695    * Return true if the event should be sent back to its parent process.
 696    * So, usual event handlers shouldn't call this.
 697    */
 698   inline bool WantReplyFromContentProcess() const {
 699     return mFlags.WantReplyFromContentProcess();
 700   }
 701   /**
 702    * Mark the event has already posted to a remote process.
 703    */
 704   inline void MarkAsPostedToRemoteProcess() {
 705     mFlags.MarkAsPostedToRemoteProcess();
 706   }
 707   /**
 708    * Reset the cross process dispatching state.  This should be used when a
 709    * process receives the event because the state is in the sender.
 710    */
 711   inline void ResetCrossProcessDispatchingState() {
 712     mFlags.ResetCrossProcessDispatchingState();
 713   }
 714   /**
 715    * Return true if the event has been posted to a remote process.
 716    */
 717   inline bool HasBeenPostedToRemoteProcess() const {
 718     return mFlags.HasBeenPostedToRemoteProcess();
 719   }
 720   /**
 721    * Return true if the event came from another process.
 722    */
 723   inline bool CameFromAnotherProcess() const {
 724     return mFlags.CameFromAnotherProcess();
 725   }
 726   /**
 727    * Mark the event as coming from another process.
 728    */
 729   inline void MarkAsComingFromAnotherProcess() {
 730     mFlags.MarkAsComingFromAnotherProcess();
 731   }
 732   /**
 733    * Mark the event is reserved by chrome.  I.e., shouldn't be dispatched to
 734    * content because it shouldn't be cancelable.
 735    */
 736   inline void MarkAsReservedByChrome() { mFlags.MarkAsReservedByChrome(); }
 737   /**
 738    * Return true if the event is reserved by chrome.
 739    */
 740   inline bool IsReservedByChrome() const { return mFlags.IsReservedByChrome(); }
 741
 742   /**
 743    * Utils for checking event types
 744    */
 745
 746   /**
 747    * As*Event() returns the pointer of the instance only when the instance is
 748    * the class or one of its derived class.
 749    */
 750 #define NS_ROOT_EVENT_CLASS(aPrefix, aName)
 751 #define NS_EVENT_CLASS(aPrefix, aName) \
 752   virtual aPrefix##aName* As##aName(); \
 753   const aPrefix##aName* As##aName() const;
 754
 755 #include "mozilla/EventClassList.h"
 756
 757 #undef NS_EVENT_CLASS
 758 #undef NS_ROOT_EVENT_CLASS
 759
 760   /**
 761    * Returns true if the event is a query content event.
 762    */
 763   bool IsQueryContentEvent() const;
 764   /**
 765    * Returns true if the event is a selection event.
 766    */
 767   bool IsSelectionEvent() const;
 768   /**
 769    * Returns true if the event is a content command event.
 770    */
 771   bool IsContentCommandEvent() const;
 772
 773   /**
 774    * Returns true if the event mMessage is one of mouse events.
 775    */
 776   bool HasMouseEventMessage() const;
 777   /**
 778    * Returns true if the event mMessage is one of drag events.
 779    */
 780   bool HasDragEventMessage() const;
 781   /**
 782    * Returns true if aMessage or mMessage is one of key events.
 783    */
 784   static bool IsKeyEventMessage(EventMessage aMessage);
 785   bool HasKeyEventMessage() const { return IsKeyEventMessage(mMessage); }
 786   /**
 787    * Returns true if the event mMessage is one of composition events or text
 788    * event.
 789    */
 790   bool HasIMEEventMessage() const;
 791
 792   /**
 793    * Returns true if the event can be sent to remote process.
 794    */
 795   bool CanBeSentToRemoteProcess() const;
 796   /**
 797    * Returns true if the original target is a remote process and the event
 798    * will be posted to the remote process later.
 799    */
 800   bool WillBeSentToRemoteProcess() const;
 801   /**
 802    * Returns true if the event is related to IME handling.  It includes
 803    * IME events, query content events and selection events.
 804    * Be careful when you use this.
 805    */
 806   bool IsIMERelatedEvent() const;
 807
 808   /**
 809    * Whether the event should be handled by the frame of the mouse cursor
 810    * position or not.  When it should be handled there (e.g., the mouse events),
 811    * this returns true.
 812    */
 813   bool IsUsingCoordinates() const;
 814   /**
 815    * Whether the event should be handled by the focused DOM window in the
 816    * same top level window's or not.  E.g., key events, IME related events
 817    * (including the query content events, they are used in IME transaction)
 818    * should be handled by the (last) focused window rather than the dispatched
 819    * window.
 820    *
 821    * NOTE: Even if this returns true, the event isn't going to be handled by the
 822    * application level active DOM window which is on another top level window.
 823    * So, when the event is fired on a deactive window, the event is going to be
 824    * handled by the last focused DOM window in the last focused window.
 825    */
 826   bool IsTargetedAtFocusedWindow() const;
 827   /**
 828    * Whether the event should be handled by the focused content or not.  E.g.,
 829    * key events, IME related events and other input events which are not handled
 830    * by the frame of the mouse cursor position.
 831    *
 832    * NOTE: Even if this returns true, the event isn't going to be handled by the
 833    * application level active DOM window which is on another top level window.
 834    * So, when the event is fired on a deactive window, the event is going to be
 835    * handled by the last focused DOM element of the last focused DOM window in
 836    * the last focused window.
 837    */
 838   bool IsTargetedAtFocusedContent() const;
 839   /**
 840    * Whether the event should cause a DOM event.
 841    */
 842   bool IsAllowedToDispatchDOMEvent() const;
 843   /**
 844    * Whether the event should be dispatched in system group.
 845    */
 846   bool IsAllowedToDispatchInSystemGroup() const;
 847   /**
 848    * Whether the event should be blocked for fingerprinting resistance.
 849    */
 850   bool IsBlockedForFingerprintingResistance() const;
 851   /**
 852    * Whether the event handler can flush pending notifications or not.
 853    */
 854   bool AllowFlushingPendingNotifications() const;
 855   /**
 856    * Initialize mComposed
 857    */
 858   void SetDefaultComposed() {
 859     switch (mClass) {
 860       case eClipboardEventClass:
 861         mFlags.mComposed = true;
 862         break;
 863       case eCompositionEventClass:
 864         mFlags.mComposed =
 865             mMessage == eCompositionStart || mMessage == eCompositionUpdate ||
 866             mMessage == eCompositionChange || mMessage == eCompositionEnd;
 867         break;
 868       case eDragEventClass:
 869         // All drag & drop events are composed
 870         mFlags.mComposed = mMessage == eDrag || mMessage == eDragEnd ||
 871                            mMessage == eDragEnter || mMessage == eDragExit ||
 872                            mMessage == eDragLeave || mMessage == eDragOver ||
 873                            mMessage == eDragStart || mMessage == eDrop;
 874         break;
 875       case eEditorInputEventClass:
 876         mFlags.mComposed =
 877             mMessage == eEditorInput || mMessage == eEditorBeforeInput;
 878         break;
 879       case eFocusEventClass:
 880         mFlags.mComposed = mMessage == eBlur || mMessage == eFocus ||
 881                            mMessage == eFocusOut || mMessage == eFocusIn;
 882         break;
 883       case eKeyboardEventClass:
 884         mFlags.mComposed =
 885             mMessage == eKeyDown || mMessage == eKeyUp || mMessage == eKeyPress;
 886         break;
 887       case eMouseEventClass:
 888         mFlags.mComposed =
 889             mMessage == eMouseClick || mMessage == eMouseDoubleClick ||
 890             mMessage == eMouseAuxClick || mMessage == eMouseDown ||
 891             mMessage == eMouseUp || mMessage == eMouseOver ||
 892             mMessage == eMouseOut || mMessage == eMouseMove ||
 893             mMessage == eContextMenu || mMessage == eXULPopupShowing ||
 894             mMessage == eXULPopupHiding || mMessage == eXULPopupShown ||
 895             mMessage == eXULPopupHidden;
 896         break;
 897       case ePointerEventClass:
 898         // All pointer events are composed
 899         mFlags.mComposed =
 900             mMessage == ePointerDown || mMessage == ePointerMove ||
 901             mMessage == ePointerUp || mMessage == ePointerCancel ||
 902             mMessage == ePointerOver || mMessage == ePointerOut ||
 903             mMessage == ePointerGotCapture || mMessage == ePointerLostCapture;
 904         break;
 905       case eTouchEventClass:
 906         // All touch events are composed
 907         mFlags.mComposed = mMessage == eTouchStart || mMessage == eTouchEnd ||
 908                            mMessage == eTouchMove || mMessage == eTouchCancel;
 909         break;
 910       case eUIEventClass:
 911         mFlags.mComposed = mMessage == eLegacyDOMFocusIn ||
 912                            mMessage == eLegacyDOMFocusOut ||
 913                            mMessage == eLegacyDOMActivate;
 914         break;
 915       case eWheelEventClass:
 916         // All wheel events are composed
 917         mFlags.mComposed = mMessage == eWheel;
 918         break;
 919       case eMouseScrollEventClass:
 920         // Legacy mouse scroll events are composed too, for consistency with
 921         // wheel.
 922         mFlags.mComposed = mMessage == eLegacyMouseLineOrPageScroll ||
 923                            mMessage == eLegacyMousePixelScroll;
 924         break;
 925       default:
 926         mFlags.mComposed = false;
 927         break;
 928     }
 929   }
 930
 931   void SetComposed(const nsAString& aEventTypeArg) {
 932     mFlags.mComposed =  // composition events
 933         aEventTypeArg.EqualsLiteral("compositionstart") ||
 934         aEventTypeArg.EqualsLiteral("compositionupdate") ||
 935         aEventTypeArg.EqualsLiteral("compositionend") ||
 936         aEventTypeArg.EqualsLiteral("text") ||
 937         // drag and drop events
 938         aEventTypeArg.EqualsLiteral("dragstart") ||
 939         aEventTypeArg.EqualsLiteral("drag") ||
 940         aEventTypeArg.EqualsLiteral("dragenter") ||
 941         aEventTypeArg.EqualsLiteral("dragexit") ||
 942         aEventTypeArg.EqualsLiteral("dragleave") ||
 943         aEventTypeArg.EqualsLiteral("dragover") ||
 944         aEventTypeArg.EqualsLiteral("drop") ||
 945         aEventTypeArg.EqualsLiteral("dropend") ||
 946         // editor input events
 947         aEventTypeArg.EqualsLiteral("input") ||
 948         aEventTypeArg.EqualsLiteral("beforeinput") ||
 949         // focus events
 950         aEventTypeArg.EqualsLiteral("blur") ||
 951         aEventTypeArg.EqualsLiteral("focus") ||
 952         aEventTypeArg.EqualsLiteral("focusin") ||
 953         aEventTypeArg.EqualsLiteral("focusout") ||
 954         // keyboard events
 955         aEventTypeArg.EqualsLiteral("keydown") ||
 956         aEventTypeArg.EqualsLiteral("keyup") ||
 957         aEventTypeArg.EqualsLiteral("keypress") ||
 958         // mouse events
 959         aEventTypeArg.EqualsLiteral("click") ||
 960         aEventTypeArg.EqualsLiteral("dblclick") ||
 961         aEventTypeArg.EqualsLiteral("mousedown") ||
 962         aEventTypeArg.EqualsLiteral("mouseup") ||
 963         aEventTypeArg.EqualsLiteral("mouseenter") ||
 964         aEventTypeArg.EqualsLiteral("mouseleave") ||
 965         aEventTypeArg.EqualsLiteral("mouseover") ||
 966         aEventTypeArg.EqualsLiteral("mouseout") ||
 967         aEventTypeArg.EqualsLiteral("mousemove") ||
 968         aEventTypeArg.EqualsLiteral("contextmenu") ||
 969         // pointer events
 970         aEventTypeArg.EqualsLiteral("pointerdown") ||
 971         aEventTypeArg.EqualsLiteral("pointermove") ||
 972         aEventTypeArg.EqualsLiteral("pointerup") ||
 973         aEventTypeArg.EqualsLiteral("pointercancel") ||
 974         aEventTypeArg.EqualsLiteral("pointerover") ||
 975         aEventTypeArg.EqualsLiteral("pointerout") ||
 976         aEventTypeArg.EqualsLiteral("pointerenter") ||
 977         aEventTypeArg.EqualsLiteral("pointerleave") ||
 978         aEventTypeArg.EqualsLiteral("gotpointercapture") ||
 979         aEventTypeArg.EqualsLiteral("lostpointercapture") ||
 980         // touch events
 981         aEventTypeArg.EqualsLiteral("touchstart") ||
 982         aEventTypeArg.EqualsLiteral("touchend") ||
 983         aEventTypeArg.EqualsLiteral("touchmove") ||
 984         aEventTypeArg.EqualsLiteral("touchcancel") ||
 985         // UI legacy events
 986         aEventTypeArg.EqualsLiteral("DOMFocusIn") ||
 987         aEventTypeArg.EqualsLiteral("DOMFocusOut") ||
 988         aEventTypeArg.EqualsLiteral("DOMActivate") ||
 989         // wheel events
 990         aEventTypeArg.EqualsLiteral("wheel");
 991   }
 992
 993   void SetComposed(bool aComposed) { mFlags.mComposed = aComposed; }
 994
 995   void SetDefaultComposedInNativeAnonymousContent() {
 996     // For compatibility concerns, we set mComposedInNativeAnonymousContent to
 997     // false for those events we want to stop propagation.
 998     //
 999     // nsVideoFrame may create anonymous image element which fires eLoad,
1000     // eLoadStart, eLoadEnd, eLoadError. We don't want these events cross
1001     // the boundary of NAC
1002     mFlags.mComposedInNativeAnonymousContent =
1003         mMessage != eLoad && mMessage != eLoadStart && mMessage != eLoadEnd &&
1004         mMessage != eLoadError;
1005   }
1006
1007   bool IsUserAction() const;
1008 };
1009
1010 /******************************************************************************
1011  * mozilla::WidgetGUIEvent
1012  ******************************************************************************/
1013
1014 class WidgetGUIEvent : public WidgetEvent {
1015  protected:
1016   WidgetGUIEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
1017                  EventClassID aEventClassID,
1018                  const WidgetEventTime* aTime = nullptr)
1019       : WidgetEvent(aIsTrusted, aMessage, aEventClassID, aTime),
1020         mWidget(aWidget) {}
1021
1022   WidgetGUIEvent() = default;
1023
1024  public:
1025   virtual WidgetGUIEvent* AsGUIEvent() override { return this; }
1026
1027   WidgetGUIEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
1028                  const WidgetEventTime* aTime = nullptr)
1029       : WidgetEvent(aIsTrusted, aMessage, eGUIEventClass, aTime),
1030         mWidget(aWidget) {}
1031
1032   virtual WidgetEvent* Duplicate() const override {
1033     MOZ_ASSERT(mClass == eGUIEventClass,
1034                "Duplicate() must be overridden by sub class");
1035     // Not copying widget, it is a weak reference.
1036     WidgetGUIEvent* result = new WidgetGUIEvent(false, mMessage, nullptr, this);
1037     result->AssignGUIEventData(*this, true);
1038     result->mFlags = mFlags;
1039     return result;
1040   }
1041
1042   // Originator of the event
1043   nsCOMPtr<nsIWidget> mWidget;
1044
1045   void AssignGUIEventData(const WidgetGUIEvent& aEvent, bool aCopyTargets) {
1046     AssignEventData(aEvent, aCopyTargets);
1047     // widget should be initialized with the constructor.
1048   }
1049 };
1050
1051 /******************************************************************************
1052  * mozilla::Modifier
1053  *
1054  * All modifier keys should be defined here.  This is used for managing
1055  * modifier states for DOM Level 3 or later.
1056  ******************************************************************************/
1057
1058 enum Modifier {
1059   MODIFIER_NONE = 0x0000,
1060   MODIFIER_ALT = 0x0001,
1061   MODIFIER_ALTGRAPH = 0x0002,
1062   MODIFIER_CAPSLOCK = 0x0004,
1063   MODIFIER_CONTROL = 0x0008,
1064   MODIFIER_FN = 0x0010,
1065   MODIFIER_FNLOCK = 0x0020,
1066   MODIFIER_META = 0x0040,
1067   MODIFIER_NUMLOCK = 0x0080,
1068   MODIFIER_SCROLLLOCK = 0x0100,
1069   MODIFIER_SHIFT = 0x0200,
1070   MODIFIER_SYMBOL = 0x0400,
1071   MODIFIER_SYMBOLLOCK = 0x0800,
1072 };
1073
1074 /******************************************************************************
1075  * Modifier key names.
1076  ******************************************************************************/
1077
1078 #define NS_DOM_KEYNAME_ALT "Alt"
1079 #define NS_DOM_KEYNAME_ALTGRAPH "AltGraph"
1080 #define NS_DOM_KEYNAME_CAPSLOCK "CapsLock"
1081 #define NS_DOM_KEYNAME_CONTROL "Control"
1082 #define NS_DOM_KEYNAME_FN "Fn"
1083 #define NS_DOM_KEYNAME_FNLOCK "FnLock"
1084 #define NS_DOM_KEYNAME_META "Meta"
1085 #define NS_DOM_KEYNAME_NUMLOCK "NumLock"
1086 #define NS_DOM_KEYNAME_SCROLLLOCK "ScrollLock"
1087 #define NS_DOM_KEYNAME_SHIFT "Shift"
1088 #define NS_DOM_KEYNAME_SYMBOL "Symbol"
1089 #define NS_DOM_KEYNAME_SYMBOLLOCK "SymbolLock"
1090 #define NS_DOM_KEYNAME_OS "OS"
1091
1092 /******************************************************************************
1093  * mozilla::Modifiers
1094  ******************************************************************************/
1095
1096 typedef uint16_t Modifiers;
1097
1098 class MOZ_STACK_CLASS GetModifiersName final : public nsAutoCString {
1099  public:
1100   explicit GetModifiersName(Modifiers aModifiers) {
1101     if (aModifiers & MODIFIER_ALT) {
1102       AssignLiteral(NS_DOM_KEYNAME_ALT);
1103     }
1104     if (aModifiers & MODIFIER_ALTGRAPH) {
1105       MaybeAppendSeparator();
1106       AppendLiteral(NS_DOM_KEYNAME_ALTGRAPH);
1107     }
1108     if (aModifiers & MODIFIER_CAPSLOCK) {
1109       MaybeAppendSeparator();
1110       AppendLiteral(NS_DOM_KEYNAME_CAPSLOCK);
1111     }
1112     if (aModifiers & MODIFIER_CONTROL) {
1113       MaybeAppendSeparator();
1114       AppendLiteral(NS_DOM_KEYNAME_CONTROL);
1115     }
1116     if (aModifiers & MODIFIER_FN) {
1117       MaybeAppendSeparator();
1118       AppendLiteral(NS_DOM_KEYNAME_FN);
1119     }
1120     if (aModifiers & MODIFIER_FNLOCK) {
1121       MaybeAppendSeparator();
1122       AppendLiteral(NS_DOM_KEYNAME_FNLOCK);
1123     }
1124     if (aModifiers & MODIFIER_META) {
1125       MaybeAppendSeparator();
1126       AppendLiteral(NS_DOM_KEYNAME_META);
1127     }
1128     if (aModifiers & MODIFIER_NUMLOCK) {
1129       MaybeAppendSeparator();
1130       AppendLiteral(NS_DOM_KEYNAME_NUMLOCK);
1131     }
1132     if (aModifiers & MODIFIER_SCROLLLOCK) {
1133       MaybeAppendSeparator();
1134       AppendLiteral(NS_DOM_KEYNAME_SCROLLLOCK);
1135     }
1136     if (aModifiers & MODIFIER_SHIFT) {
1137       MaybeAppendSeparator();
1138       AppendLiteral(NS_DOM_KEYNAME_SHIFT);
1139     }
1140     if (aModifiers & MODIFIER_SYMBOL) {
1141       MaybeAppendSeparator();
1142       AppendLiteral(NS_DOM_KEYNAME_SYMBOL);
1143     }
1144     if (aModifiers & MODIFIER_SYMBOLLOCK) {
1145       MaybeAppendSeparator();
1146       AppendLiteral(NS_DOM_KEYNAME_SYMBOLLOCK);
1147     }
1148     if (IsEmpty()) {
1149       AssignLiteral("none");
1150     }
1151   }
1152
1153  private:
1154   void MaybeAppendSeparator() {
1155     if (!IsEmpty()) {
1156       AppendLiteral(" | ");
1157     }
1158   }
1159 };
1160
1161 /******************************************************************************
1162  * mozilla::WidgetInputEvent
1163  ******************************************************************************/
1164
1165 class WidgetInputEvent : public WidgetGUIEvent {
1166  protected:
1167   WidgetInputEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
1168                    EventClassID aEventClassID,
1169                    const WidgetEventTime* aTime = nullptr)
1170       : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, aEventClassID, aTime),
1171         mModifiers(0) {}
1172
1173   WidgetInputEvent() : mModifiers(0) {}
1174
1175  public:
1176   virtual WidgetInputEvent* AsInputEvent() override { return this; }
1177
1178   WidgetInputEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
1179                    const WidgetEventTime* aTime = nullptr)
1180       : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, eInputEventClass, aTime),
1181         mModifiers(0) {}
1182
1183   virtual WidgetEvent* Duplicate() const override {
1184     MOZ_ASSERT(mClass == eInputEventClass,
1185                "Duplicate() must be overridden by sub class");
1186     // Not copying widget, it is a weak reference.
1187     WidgetInputEvent* result =
1188         new WidgetInputEvent(false, mMessage, nullptr, this);
1189     result->AssignInputEventData(*this, true);
1190     result->mFlags = mFlags;
1191     return result;
1192   }
1193
1194   /**
1195    * Returns a modifier of "Accel" virtual modifier which is used for shortcut
1196    * key.
1197    */
1198   static Modifier AccelModifier();
1199
1200   /**
1201    * GetModifier() returns a modifier flag which is activated by aDOMKeyName.
1202    */
1203   static Modifier GetModifier(const nsAString& aDOMKeyName);
1204
1205   // true indicates the accel key on the environment is down
1206   bool IsAccel() const { return ((mModifiers & AccelModifier()) != 0); }
1207
1208   // true indicates the shift key is down
1209   bool IsShift() const { return ((mModifiers & MODIFIER_SHIFT) != 0); }
1210   // true indicates the control key is down
1211   bool IsControl() const { return ((mModifiers & MODIFIER_CONTROL) != 0); }
1212   // true indicates the alt key is down
1213   bool IsAlt() const { return ((mModifiers & MODIFIER_ALT) != 0); }
1214   // true indicates the meta key is down (Command key on macOS, Windows logo key
1215   // on Windows, Super/Hyper key on Linux, Meta key on Android).
1216   bool IsMeta() const { return ((mModifiers & MODIFIER_META) != 0); }
1217   // true indicates the alt graph key is down
1218   // NOTE: on Mac, the option key press causes both IsAlt() and IsAltGrpah()
1219   //       return true.
1220   bool IsAltGraph() const { return ((mModifiers & MODIFIER_ALTGRAPH) != 0); }
1221   // true indicates the CapLock LED is turn on.
1222   bool IsCapsLocked() const { return ((mModifiers & MODIFIER_CAPSLOCK) != 0); }
1223   // true indicates the NumLock LED is turn on.
1224   bool IsNumLocked() const { return ((mModifiers & MODIFIER_NUMLOCK) != 0); }
1225   // true indicates the ScrollLock LED is turn on.
1226   bool IsScrollLocked() const {
1227     return ((mModifiers & MODIFIER_SCROLLLOCK) != 0);
1228   }
1229
1230   // true indicates the Fn key is down, but this is not supported by native
1231   // key event on any platform.
1232   bool IsFn() const { return ((mModifiers & MODIFIER_FN) != 0); }
1233   // true indicates the FnLock LED is turn on, but we don't know such
1234   // keyboards nor platforms.
1235   bool IsFnLocked() const { return ((mModifiers & MODIFIER_FNLOCK) != 0); }
1236   // true indicates the Symbol is down, but this is not supported by native
1237   // key event on any platforms.
1238   bool IsSymbol() const { return ((mModifiers & MODIFIER_SYMBOL) != 0); }
1239   // true indicates the SymbolLock LED is turn on, but we don't know such
1240   // keyboards nor platforms.
1241   bool IsSymbolLocked() const {
1242     return ((mModifiers & MODIFIER_SYMBOLLOCK) != 0);
1243   }
1244
1245   void InitBasicModifiers(bool aCtrlKey, bool aAltKey, bool aShiftKey,
1246                           bool aMetaKey) {
1247     mModifiers = 0;
1248     if (aCtrlKey) {
1249       mModifiers |= MODIFIER_CONTROL;
1250     }
1251     if (aAltKey) {
1252       mModifiers |= MODIFIER_ALT;
1253     }
1254     if (aShiftKey) {
1255       mModifiers |= MODIFIER_SHIFT;
1256     }
1257     if (aMetaKey) {
1258       mModifiers |= MODIFIER_META;
1259     }
1260   }
1261
1262   Modifiers mModifiers;
1263
1264   void AssignInputEventData(const WidgetInputEvent& aEvent, bool aCopyTargets) {
1265     AssignGUIEventData(aEvent, aCopyTargets);
1266
1267     mModifiers = aEvent.mModifiers;
1268   }
1269 };
1270
1271 /******************************************************************************
1272  * mozilla::InternalUIEvent
1273  *
1274  * XXX Why this inherits WidgetGUIEvent rather than WidgetEvent?
1275  ******************************************************************************/
1276
1277 class InternalUIEvent : public WidgetGUIEvent {
1278  protected:
1279   InternalUIEvent() : mDetail(0), mCausedByUntrustedEvent(false) {}
1280
1281   InternalUIEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
1282                   EventClassID aEventClassID,
1283                   const WidgetEventTime* aTime = nullptr)
1284       : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, aEventClassID, aTime),
1285         mDetail(0),
1286         mCausedByUntrustedEvent(false) {}
1287
1288   InternalUIEvent(bool aIsTrusted, EventMessage aMessage,
1289                   EventClassID aEventClassID,
1290                   const WidgetEventTime* aTime = nullptr)
1291       : WidgetGUIEvent(aIsTrusted, aMessage, nullptr, aEventClassID, aTime),
1292         mDetail(0),
1293         mCausedByUntrustedEvent(false) {}
1294
1295  public:
1296   virtual InternalUIEvent* AsUIEvent() override { return this; }
1297
1298   /**
1299    * If the UIEvent is caused by another event (e.g., click event),
1300    * aEventCausesThisEvent should be the event.  If there is no such event,
1301    * this should be nullptr.
1302    */
1303   InternalUIEvent(bool aIsTrusted, EventMessage aMessage,
1304                   const WidgetEvent* aEventCausesThisEvent,
1305                   const WidgetEventTime* aTime = nullptr)
1306       : WidgetGUIEvent(aIsTrusted, aMessage, nullptr, eUIEventClass, aTime),
1307         mDetail(0),
1308         mCausedByUntrustedEvent(aEventCausesThisEvent &&
1309                                 !aEventCausesThisEvent->IsTrusted()) {}
1310
1311   virtual WidgetEvent* Duplicate() const override {
1312     MOZ_ASSERT(mClass == eUIEventClass,
1313                "Duplicate() must be overridden by sub class");
1314     InternalUIEvent* result =
1315         new InternalUIEvent(false, mMessage, nullptr, this);
1316     result->AssignUIEventData(*this, true);
1317     result->mFlags = mFlags;
1318     return result;
1319   }
1320
1321   int32_t mDetail;
1322   // mCausedByUntrustedEvent is true if the event is caused by untrusted event.
1323   bool mCausedByUntrustedEvent;
1324
1325   // If you check the event is a trusted event and NOT caused by an untrusted
1326   // event, IsTrustable() returns what you expected.
1327   bool IsTrustable() const { return IsTrusted() && !mCausedByUntrustedEvent; }
1328
1329   void AssignUIEventData(const InternalUIEvent& aEvent, bool aCopyTargets) {
1330     AssignGUIEventData(aEvent, aCopyTargets);
1331
1332     mDetail = aEvent.mDetail;
1333     mCausedByUntrustedEvent = aEvent.mCausedByUntrustedEvent;
1334   }
1335 };
1336
1337 }  // namespace mozilla
1338
1339 #endif  // mozilla_BasicEvents_h__