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(TimeStamp aTimeStamp) : mTimeStamp(aTimeStamp) {}
 421
 422   void AssignEventTime(const WidgetEventTime& aOther) {
 423     mTimeStamp = aOther.mTimeStamp;
 424   }
 425 };
 426
 427 /******************************************************************************
 428  * mozilla::WidgetEvent
 429  ******************************************************************************/
 430
 431 class WidgetEvent : public WidgetEventTime {
 432  private:
 433   void SetDefaultCancelableAndBubbles() {
 434     switch (mClass) {
 435       case eEditorInputEventClass:
 436         mFlags.mCancelable = false;
 437         mFlags.mBubbles = mFlags.mIsTrusted;
 438         break;
 439       case eMouseEventClass:
 440         mFlags.mCancelable =
 441             (mMessage != eMouseEnter && mMessage != eMouseLeave);
 442         mFlags.mBubbles = (mMessage != eMouseEnter && mMessage != eMouseLeave);
 443         break;
 444       case ePointerEventClass:
 445         mFlags.mCancelable =
 446             (mMessage != ePointerEnter && mMessage != ePointerLeave &&
 447              mMessage != ePointerCancel && mMessage != ePointerGotCapture &&
 448              mMessage != ePointerLostCapture);
 449         mFlags.mBubbles =
 450             (mMessage != ePointerEnter && mMessage != ePointerLeave);
 451         break;
 452       case eDragEventClass:
 453         mFlags.mCancelable = (mMessage != eDragExit && mMessage != eDragLeave &&
 454                               mMessage != eDragEnd);
 455         mFlags.mBubbles = true;
 456         break;
 457       case eSMILTimeEventClass:
 458         mFlags.mCancelable = false;
 459         mFlags.mBubbles = false;
 460         break;
 461       case eTransitionEventClass:
 462       case eAnimationEventClass:
 463         mFlags.mCancelable = false;
 464         mFlags.mBubbles = true;
 465         break;
 466       case eCompositionEventClass:
 467         // XXX compositionstart is cancelable in draft of DOM3 Events.
 468         //     However, it doesn't make sense for us, we cannot cancel
 469         //     composition when we send compositionstart event.
 470         mFlags.mCancelable = false;
 471         mFlags.mBubbles = true;
 472         break;
 473       default:
 474         if (mMessage == eResize || mMessage == eMozVisualResize ||
 475             mMessage == eMozVisualScroll || mMessage == eEditorInput ||
 476             mMessage == eFormSelect) {
 477           mFlags.mCancelable = false;
 478         } else {
 479           mFlags.mCancelable = true;
 480         }
 481         mFlags.mBubbles = true;
 482         break;
 483     }
 484   }
 485
 486  protected:
 487   WidgetEvent(bool aIsTrusted, EventMessage aMessage,
 488               EventClassID aEventClassID)
 489       : WidgetEventTime(),
 490         mClass(aEventClassID),
 491         mMessage(aMessage),
 492         mRefPoint(0, 0),
 493         mLastRefPoint(0, 0),
 494         mFocusSequenceNumber(0),
 495         mSpecifiedEventType(nullptr),
 496         mPath(nullptr),
 497         mLayersId(layers::LayersId{0}) {
 498     MOZ_COUNT_CTOR(WidgetEvent);
 499     mFlags.Clear();
 500     mFlags.mIsTrusted = aIsTrusted;
 501     SetDefaultCancelableAndBubbles();
 502     SetDefaultComposed();
 503     SetDefaultComposedInNativeAnonymousContent();
 504   }
 505
 506   WidgetEvent() : WidgetEventTime(), mPath(nullptr) {
 507     MOZ_COUNT_CTOR(WidgetEvent);
 508   }
 509
 510  public:
 511   WidgetEvent(bool aIsTrusted, EventMessage aMessage)
 512       : WidgetEvent(aIsTrusted, aMessage, eBasicEventClass) {}
 513
 514   MOZ_COUNTED_DTOR_VIRTUAL(WidgetEvent)
 515
 516   WidgetEvent(const WidgetEvent& aOther) : WidgetEventTime() {
 517     MOZ_COUNT_CTOR(WidgetEvent);
 518     *this = aOther;
 519   }
 520   WidgetEvent& operator=(const WidgetEvent& aOther) = default;
 521
 522   WidgetEvent(WidgetEvent&& aOther)
 523       : WidgetEventTime(std::move(aOther)),
 524         mClass(aOther.mClass),
 525         mMessage(aOther.mMessage),
 526         mRefPoint(std::move(aOther.mRefPoint)),
 527         mLastRefPoint(std::move(aOther.mLastRefPoint)),
 528         mFocusSequenceNumber(aOther.mFocusSequenceNumber),
 529         mFlags(std::move(aOther.mFlags)),
 530         mSpecifiedEventType(std::move(aOther.mSpecifiedEventType)),
 531         mSpecifiedEventTypeString(std::move(aOther.mSpecifiedEventTypeString)),
 532         mTarget(std::move(aOther.mTarget)),
 533         mCurrentTarget(std::move(aOther.mCurrentTarget)),
 534         mOriginalTarget(std::move(aOther.mOriginalTarget)),
 535         mRelatedTarget(std::move(aOther.mRelatedTarget)),
 536         mOriginalRelatedTarget(std::move(aOther.mOriginalRelatedTarget)),
 537         mPath(std::move(aOther.mPath)) {
 538     MOZ_COUNT_CTOR(WidgetEvent);
 539   }
 540   WidgetEvent& operator=(WidgetEvent&& aOther) = default;
 541
 542   virtual WidgetEvent* Duplicate() const {
 543     MOZ_ASSERT(mClass == eBasicEventClass,
 544                "Duplicate() must be overridden by sub class");
 545     WidgetEvent* result = new WidgetEvent(false, mMessage);
 546     result->AssignEventData(*this, true);
 547     result->mFlags = mFlags;
 548     return result;
 549   }
 550
 551   EventClassID mClass;
 552   EventMessage mMessage;
 553   // Relative to the widget of the event, or if there is no widget then it is
 554   // in screen coordinates. Not modified by layout code.
 555   // This is in visual coordinates, i.e. the correct RelativeTo value that
 556   // expresses what this is relative to is `{viewportFrame, Visual}`, where
 557   // `viewportFrame` is the viewport frame of the widget's root document.
 558   LayoutDeviceIntPoint mRefPoint;
 559   // The previous mRefPoint, if known, used to calculate mouse movement deltas.
 560   LayoutDeviceIntPoint mLastRefPoint;
 561   // The sequence number of the last potentially focus changing event handled
 562   // by APZ. This is used to track when that event has been processed by
 563   // content, and focus can be reconfirmed for async keyboard scrolling.
 564   uint64_t mFocusSequenceNumber;
 565   // See BaseEventFlags definition for the detail.
 566   BaseEventFlags mFlags;
 567
 568   // If JS creates an event with unknown event type or known event type but
 569   // for different event interface, the event type is stored to this.
 570   // NOTE: This is always used if the instance is a WidgetCommandEvent instance
 571   //       or "input" event is dispatched with dom::Event class.
 572   RefPtr<nsAtom> mSpecifiedEventType;
 573
 574   // nsAtom isn't available on non-main thread due to unsafe.  Therefore,
 575   // mSpecifiedEventTypeString is used instead of mSpecifiedEventType if
 576   // the event is created in non-main thread.
 577   nsString mSpecifiedEventTypeString;
 578
 579   // Event targets, needed by DOM Events
 580   // Note that when you need event target for DOM event, you should use
 581   // Get*DOMEventTarget() instead of accessing these members directly.
 582   nsCOMPtr<dom::EventTarget> mTarget;
 583   nsCOMPtr<dom::EventTarget> mCurrentTarget;
 584   nsCOMPtr<dom::EventTarget> mOriginalTarget;
 585
 586   /// The possible related target
 587   nsCOMPtr<dom::EventTarget> mRelatedTarget;
 588   nsCOMPtr<dom::EventTarget> mOriginalRelatedTarget;
 589
 590   nsTArray<EventTargetChainItem>* mPath;
 591
 592   // The LayersId of the content process that this event should be
 593   // dispatched to. This field is only used in the chrome process
 594   // and doesn't get remoted to child processes.
 595   layers::LayersId mLayersId;
 596
 597   dom::EventTarget* GetDOMEventTarget() const;
 598   dom::EventTarget* GetCurrentDOMEventTarget() const;
 599   dom::EventTarget* GetOriginalDOMEventTarget() const;
 600
 601   void AssignEventData(const WidgetEvent& aEvent, bool aCopyTargets) {
 602     // mClass should be initialized with the constructor.
 603     // mMessage should be initialized with the constructor.
 604     mRefPoint = aEvent.mRefPoint;
 605     // mLastRefPoint doesn't need to be copied.
 606     mFocusSequenceNumber = aEvent.mFocusSequenceNumber;
 607     // mLayersId intentionally not copied, since it's not used within content
 608     AssignEventTime(aEvent);
 609     // mFlags should be copied manually if it's necessary.
 610     mSpecifiedEventType = aEvent.mSpecifiedEventType;
 611     // mSpecifiedEventTypeString should be copied manually if it's necessary.
 612     mTarget = aCopyTargets ? aEvent.mTarget : nullptr;
 613     mCurrentTarget = aCopyTargets ? aEvent.mCurrentTarget : nullptr;
 614     mOriginalTarget = aCopyTargets ? aEvent.mOriginalTarget : nullptr;
 615     mRelatedTarget = aCopyTargets ? aEvent.mRelatedTarget : nullptr;
 616     mOriginalRelatedTarget =
 617         aCopyTargets ? aEvent.mOriginalRelatedTarget : nullptr;
 618   }
 619
 620   /**
 621    * Helper methods for methods of DOM Event.
 622    */
 623   void StopPropagation() { mFlags.StopPropagation(); }
 624   void StopImmediatePropagation() { mFlags.StopImmediatePropagation(); }
 625   void PreventDefault(bool aCalledByDefaultHandler = true,
 626                       nsIPrincipal* aPrincipal = nullptr);
 627
 628   void PreventDefaultBeforeDispatch(
 629       CrossProcessForwarding aCrossProcessForwarding) {
 630     mFlags.PreventDefaultBeforeDispatch(aCrossProcessForwarding);
 631   }
 632   bool DefaultPrevented() const { return mFlags.DefaultPrevented(); }
 633   bool DefaultPreventedByContent() const {
 634     return mFlags.DefaultPreventedByContent();
 635   }
 636   bool IsTrusted() const { return mFlags.IsTrusted(); }
 637   bool PropagationStopped() const { return mFlags.PropagationStopped(); }
 638
 639   /**
 640    * Prevent to be dispatched to remote process.
 641    */
 642   inline void StopCrossProcessForwarding() {
 643     mFlags.StopCrossProcessForwarding();
 644   }
 645   /**
 646    * Return true if the event shouldn't be dispatched to remote process.
 647    */
 648   inline bool IsCrossProcessForwardingStopped() const {
 649     return mFlags.IsCrossProcessForwardingStopped();
 650   }
 651   /**
 652    * Mark the event as waiting reply from remote process.
 653    * Note that this also stops immediate propagation in current process.
 654    */
 655   inline void MarkAsWaitingReplyFromRemoteProcess() {
 656     mFlags.MarkAsWaitingReplyFromRemoteProcess();
 657   }
 658   /**
 659    * Reset "waiting reply from remote process" state.  This is useful when
 660    * you dispatch a copy of an event coming from different process.
 661    */
 662   inline void ResetWaitingReplyFromRemoteProcessState() {
 663     mFlags.ResetWaitingReplyFromRemoteProcessState();
 664   }
 665   /**
 666    * Return true if the event handler should wait reply event.  I.e., if this
 667    * returns true, any event handler should do nothing with the event.
 668    */
 669   inline bool IsWaitingReplyFromRemoteProcess() const {
 670     return mFlags.IsWaitingReplyFromRemoteProcess();
 671   }
 672   /**
 673    * Mark the event as already handled in the remote process.  This should be
 674    * called when initializing reply events.
 675    */
 676   inline void MarkAsHandledInRemoteProcess() {
 677     mFlags.MarkAsHandledInRemoteProcess();
 678   }
 679   /**
 680    * Return true if the event has already been handled in the remote process.
 681    * I.e., if this returns true, the event is a reply event.
 682    */
 683   inline bool IsHandledInRemoteProcess() const {
 684     return mFlags.IsHandledInRemoteProcess();
 685   }
 686   /**
 687    * Return true if the event should be sent back to its parent process.
 688    * So, usual event handlers shouldn't call this.
 689    */
 690   inline bool WantReplyFromContentProcess() const {
 691     return mFlags.WantReplyFromContentProcess();
 692   }
 693   /**
 694    * Mark the event has already posted to a remote process.
 695    */
 696   inline void MarkAsPostedToRemoteProcess() {
 697     mFlags.MarkAsPostedToRemoteProcess();
 698   }
 699   /**
 700    * Reset the cross process dispatching state.  This should be used when a
 701    * process receives the event because the state is in the sender.
 702    */
 703   inline void ResetCrossProcessDispatchingState() {
 704     mFlags.ResetCrossProcessDispatchingState();
 705   }
 706   /**
 707    * Return true if the event has been posted to a remote process.
 708    */
 709   inline bool HasBeenPostedToRemoteProcess() const {
 710     return mFlags.HasBeenPostedToRemoteProcess();
 711   }
 712   /**
 713    * Return true if the event came from another process.
 714    */
 715   inline bool CameFromAnotherProcess() const {
 716     return mFlags.CameFromAnotherProcess();
 717   }
 718   /**
 719    * Mark the event as coming from another process.
 720    */
 721   inline void MarkAsComingFromAnotherProcess() {
 722     mFlags.MarkAsComingFromAnotherProcess();
 723   }
 724   /**
 725    * Mark the event is reserved by chrome.  I.e., shouldn't be dispatched to
 726    * content because it shouldn't be cancelable.
 727    */
 728   inline void MarkAsReservedByChrome() { mFlags.MarkAsReservedByChrome(); }
 729   /**
 730    * Return true if the event is reserved by chrome.
 731    */
 732   inline bool IsReservedByChrome() const { return mFlags.IsReservedByChrome(); }
 733
 734   /**
 735    * Utils for checking event types
 736    */
 737
 738   /**
 739    * As*Event() returns the pointer of the instance only when the instance is
 740    * the class or one of its derived class.
 741    */
 742 #define NS_ROOT_EVENT_CLASS(aPrefix, aName)
 743 #define NS_EVENT_CLASS(aPrefix, aName) \
 744   virtual aPrefix##aName* As##aName(); \
 745   const aPrefix##aName* As##aName() const;
 746
 747 #include "mozilla/EventClassList.h"
 748
 749 #undef NS_EVENT_CLASS
 750 #undef NS_ROOT_EVENT_CLASS
 751
 752   /**
 753    * Returns true if the event is a query content event.
 754    */
 755   bool IsQueryContentEvent() const;
 756   /**
 757    * Returns true if the event is a selection event.
 758    */
 759   bool IsSelectionEvent() const;
 760   /**
 761    * Returns true if the event is a content command event.
 762    */
 763   bool IsContentCommandEvent() const;
 764
 765   /**
 766    * Returns true if the event mMessage is one of mouse events.
 767    */
 768   bool HasMouseEventMessage() const;
 769   /**
 770    * Returns true if the event mMessage is one of drag events.
 771    */
 772   bool HasDragEventMessage() const;
 773   /**
 774    * Returns true if aMessage or mMessage is one of key events.
 775    */
 776   static bool IsKeyEventMessage(EventMessage aMessage);
 777   bool HasKeyEventMessage() const { return IsKeyEventMessage(mMessage); }
 778   /**
 779    * Returns true if the event mMessage is one of composition events or text
 780    * event.
 781    */
 782   bool HasIMEEventMessage() const;
 783
 784   /**
 785    * Returns true if the event can be sent to remote process.
 786    */
 787   bool CanBeSentToRemoteProcess() const;
 788   /**
 789    * Returns true if the original target is a remote process and the event
 790    * will be posted to the remote process later.
 791    */
 792   bool WillBeSentToRemoteProcess() const;
 793   /**
 794    * Returns true if the event is related to IME handling.  It includes
 795    * IME events, query content events and selection events.
 796    * Be careful when you use this.
 797    */
 798   bool IsIMERelatedEvent() const;
 799
 800   /**
 801    * Whether the event should be handled by the frame of the mouse cursor
 802    * position or not.  When it should be handled there (e.g., the mouse events),
 803    * this returns true.
 804    */
 805   bool IsUsingCoordinates() const;
 806   /**
 807    * Whether the event should be handled by the focused DOM window in the
 808    * same top level window's or not.  E.g., key events, IME related events
 809    * (including the query content events, they are used in IME transaction)
 810    * should be handled by the (last) focused window rather than the dispatched
 811    * window.
 812    *
 813    * NOTE: Even if this returns true, the event isn't going to be handled by the
 814    * application level active DOM window which is on another top level window.
 815    * So, when the event is fired on a deactive window, the event is going to be
 816    * handled by the last focused DOM window in the last focused window.
 817    */
 818   bool IsTargetedAtFocusedWindow() const;
 819   /**
 820    * Whether the event should be handled by the focused content or not.  E.g.,
 821    * key events, IME related events and other input events which are not handled
 822    * by the frame of the mouse cursor position.
 823    *
 824    * NOTE: Even if this returns true, the event isn't going to be handled by the
 825    * application level active DOM window which is on another top level window.
 826    * So, when the event is fired on a deactive window, the event is going to be
 827    * handled by the last focused DOM element of the last focused DOM window in
 828    * the last focused window.
 829    */
 830   bool IsTargetedAtFocusedContent() const;
 831   /**
 832    * Whether the event should cause a DOM event.
 833    */
 834   bool IsAllowedToDispatchDOMEvent() const;
 835   /**
 836    * Whether the event should be dispatched in system group.
 837    */
 838   bool IsAllowedToDispatchInSystemGroup() const;
 839   /**
 840    * Whether the event should be blocked for fingerprinting resistance.
 841    */
 842   bool IsBlockedForFingerprintingResistance() const;
 843   /**
 844    * Initialize mComposed
 845    */
 846   void SetDefaultComposed() {
 847     switch (mClass) {
 848       case eClipboardEventClass:
 849         mFlags.mComposed = true;
 850         break;
 851       case eCompositionEventClass:
 852         mFlags.mComposed =
 853             mMessage == eCompositionStart || mMessage == eCompositionUpdate ||
 854             mMessage == eCompositionChange || mMessage == eCompositionEnd;
 855         break;
 856       case eDragEventClass:
 857         // All drag & drop events are composed
 858         mFlags.mComposed = mMessage == eDrag || mMessage == eDragEnd ||
 859                            mMessage == eDragEnter || mMessage == eDragExit ||
 860                            mMessage == eDragLeave || mMessage == eDragOver ||
 861                            mMessage == eDragStart || mMessage == eDrop;
 862         break;
 863       case eEditorInputEventClass:
 864         mFlags.mComposed =
 865             mMessage == eEditorInput || mMessage == eEditorBeforeInput;
 866         break;
 867       case eFocusEventClass:
 868         mFlags.mComposed = mMessage == eBlur || mMessage == eFocus ||
 869                            mMessage == eFocusOut || mMessage == eFocusIn;
 870         break;
 871       case eKeyboardEventClass:
 872         mFlags.mComposed =
 873             mMessage == eKeyDown || mMessage == eKeyUp || mMessage == eKeyPress;
 874         break;
 875       case eMouseEventClass:
 876         mFlags.mComposed =
 877             mMessage == eMouseClick || mMessage == eMouseDoubleClick ||
 878             mMessage == eMouseAuxClick || mMessage == eMouseDown ||
 879             mMessage == eMouseUp || mMessage == eMouseOver ||
 880             mMessage == eMouseOut || mMessage == eMouseMove ||
 881             mMessage == eContextMenu || mMessage == eXULPopupShowing ||
 882             mMessage == eXULPopupHiding || mMessage == eXULPopupShown ||
 883             mMessage == eXULPopupHidden;
 884         break;
 885       case ePointerEventClass:
 886         // All pointer events are composed
 887         mFlags.mComposed =
 888             mMessage == ePointerDown || mMessage == ePointerMove ||
 889             mMessage == ePointerUp || mMessage == ePointerCancel ||
 890             mMessage == ePointerOver || mMessage == ePointerOut ||
 891             mMessage == ePointerGotCapture || mMessage == ePointerLostCapture;
 892         break;
 893       case eTouchEventClass:
 894         // All touch events are composed
 895         mFlags.mComposed = mMessage == eTouchStart || mMessage == eTouchEnd ||
 896                            mMessage == eTouchMove || mMessage == eTouchCancel;
 897         break;
 898       case eUIEventClass:
 899         mFlags.mComposed = mMessage == eLegacyDOMFocusIn ||
 900                            mMessage == eLegacyDOMFocusOut ||
 901                            mMessage == eLegacyDOMActivate;
 902         break;
 903       case eWheelEventClass:
 904         // All wheel events are composed
 905         mFlags.mComposed = mMessage == eWheel;
 906         break;
 907       case eMouseScrollEventClass:
 908         // Legacy mouse scroll events are composed too, for consistency with
 909         // wheel.
 910         mFlags.mComposed = mMessage == eLegacyMouseLineOrPageScroll ||
 911                            mMessage == eLegacyMousePixelScroll;
 912         break;
 913       default:
 914         mFlags.mComposed = false;
 915         break;
 916     }
 917   }
 918
 919   void SetComposed(const nsAString& aEventTypeArg) {
 920     mFlags.mComposed =  // composition events
 921         aEventTypeArg.EqualsLiteral("compositionstart") ||
 922         aEventTypeArg.EqualsLiteral("compositionupdate") ||
 923         aEventTypeArg.EqualsLiteral("compositionend") ||
 924         aEventTypeArg.EqualsLiteral("text") ||
 925         // drag and drop events
 926         aEventTypeArg.EqualsLiteral("dragstart") ||
 927         aEventTypeArg.EqualsLiteral("drag") ||
 928         aEventTypeArg.EqualsLiteral("dragenter") ||
 929         aEventTypeArg.EqualsLiteral("dragexit") ||
 930         aEventTypeArg.EqualsLiteral("dragleave") ||
 931         aEventTypeArg.EqualsLiteral("dragover") ||
 932         aEventTypeArg.EqualsLiteral("drop") ||
 933         aEventTypeArg.EqualsLiteral("dropend") ||
 934         // editor input events
 935         aEventTypeArg.EqualsLiteral("input") ||
 936         aEventTypeArg.EqualsLiteral("beforeinput") ||
 937         // focus events
 938         aEventTypeArg.EqualsLiteral("blur") ||
 939         aEventTypeArg.EqualsLiteral("focus") ||
 940         aEventTypeArg.EqualsLiteral("focusin") ||
 941         aEventTypeArg.EqualsLiteral("focusout") ||
 942         // keyboard events
 943         aEventTypeArg.EqualsLiteral("keydown") ||
 944         aEventTypeArg.EqualsLiteral("keyup") ||
 945         aEventTypeArg.EqualsLiteral("keypress") ||
 946         // mouse events
 947         aEventTypeArg.EqualsLiteral("click") ||
 948         aEventTypeArg.EqualsLiteral("dblclick") ||
 949         aEventTypeArg.EqualsLiteral("mousedown") ||
 950         aEventTypeArg.EqualsLiteral("mouseup") ||
 951         aEventTypeArg.EqualsLiteral("mouseenter") ||
 952         aEventTypeArg.EqualsLiteral("mouseleave") ||
 953         aEventTypeArg.EqualsLiteral("mouseover") ||
 954         aEventTypeArg.EqualsLiteral("mouseout") ||
 955         aEventTypeArg.EqualsLiteral("mousemove") ||
 956         aEventTypeArg.EqualsLiteral("contextmenu") ||
 957         // pointer events
 958         aEventTypeArg.EqualsLiteral("pointerdown") ||
 959         aEventTypeArg.EqualsLiteral("pointermove") ||
 960         aEventTypeArg.EqualsLiteral("pointerup") ||
 961         aEventTypeArg.EqualsLiteral("pointercancel") ||
 962         aEventTypeArg.EqualsLiteral("pointerover") ||
 963         aEventTypeArg.EqualsLiteral("pointerout") ||
 964         aEventTypeArg.EqualsLiteral("pointerenter") ||
 965         aEventTypeArg.EqualsLiteral("pointerleave") ||
 966         aEventTypeArg.EqualsLiteral("gotpointercapture") ||
 967         aEventTypeArg.EqualsLiteral("lostpointercapture") ||
 968         // touch events
 969         aEventTypeArg.EqualsLiteral("touchstart") ||
 970         aEventTypeArg.EqualsLiteral("touchend") ||
 971         aEventTypeArg.EqualsLiteral("touchmove") ||
 972         aEventTypeArg.EqualsLiteral("touchcancel") ||
 973         // UI legacy events
 974         aEventTypeArg.EqualsLiteral("DOMFocusIn") ||
 975         aEventTypeArg.EqualsLiteral("DOMFocusOut") ||
 976         aEventTypeArg.EqualsLiteral("DOMActivate") ||
 977         // wheel events
 978         aEventTypeArg.EqualsLiteral("wheel");
 979   }
 980
 981   void SetComposed(bool aComposed) { mFlags.mComposed = aComposed; }
 982
 983   void SetDefaultComposedInNativeAnonymousContent() {
 984     // For compatibility concerns, we set mComposedInNativeAnonymousContent to
 985     // false for those events we want to stop propagation.
 986     //
 987     // nsVideoFrame may create anonymous image element which fires eLoad,
 988     // eLoadStart, eLoadEnd, eLoadError. We don't want these events cross
 989     // the boundary of NAC
 990     mFlags.mComposedInNativeAnonymousContent =
 991         mMessage != eLoad && mMessage != eLoadStart && mMessage != eLoadEnd &&
 992         mMessage != eLoadError;
 993   }
 994
 995   bool IsUserAction() const;
 996 };
 997
 998 /******************************************************************************
 999  * mozilla::WidgetGUIEvent
1000  ******************************************************************************/
1001
1002 class WidgetGUIEvent : public WidgetEvent {
1003  protected:
1004   WidgetGUIEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
1005                  EventClassID aEventClassID)
1006       : WidgetEvent(aIsTrusted, aMessage, aEventClassID), mWidget(aWidget) {}
1007
1008   WidgetGUIEvent() = default;
1009
1010  public:
1011   virtual WidgetGUIEvent* AsGUIEvent() override { return this; }
1012
1013   WidgetGUIEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget)
1014       : WidgetEvent(aIsTrusted, aMessage, eGUIEventClass), mWidget(aWidget) {}
1015
1016   virtual WidgetEvent* Duplicate() const override {
1017     MOZ_ASSERT(mClass == eGUIEventClass,
1018                "Duplicate() must be overridden by sub class");
1019     // Not copying widget, it is a weak reference.
1020     WidgetGUIEvent* result = new WidgetGUIEvent(false, mMessage, nullptr);
1021     result->AssignGUIEventData(*this, true);
1022     result->mFlags = mFlags;
1023     return result;
1024   }
1025
1026   // Originator of the event
1027   nsCOMPtr<nsIWidget> mWidget;
1028
1029   void AssignGUIEventData(const WidgetGUIEvent& aEvent, bool aCopyTargets) {
1030     AssignEventData(aEvent, aCopyTargets);
1031     // widget should be initialized with the constructor.
1032   }
1033 };
1034
1035 /******************************************************************************
1036  * mozilla::Modifier
1037  *
1038  * All modifier keys should be defined here.  This is used for managing
1039  * modifier states for DOM Level 3 or later.
1040  ******************************************************************************/
1041
1042 enum Modifier {
1043   MODIFIER_NONE = 0x0000,
1044   MODIFIER_ALT = 0x0001,
1045   MODIFIER_ALTGRAPH = 0x0002,
1046   MODIFIER_CAPSLOCK = 0x0004,
1047   MODIFIER_CONTROL = 0x0008,
1048   MODIFIER_FN = 0x0010,
1049   MODIFIER_FNLOCK = 0x0020,
1050   MODIFIER_META = 0x0040,
1051   MODIFIER_NUMLOCK = 0x0080,
1052   MODIFIER_SCROLLLOCK = 0x0100,
1053   MODIFIER_SHIFT = 0x0200,
1054   MODIFIER_SYMBOL = 0x0400,
1055   MODIFIER_SYMBOLLOCK = 0x0800,
1056   MODIFIER_OS = 0x1000
1057 };
1058
1059 /******************************************************************************
1060  * Modifier key names.
1061  ******************************************************************************/
1062
1063 #define NS_DOM_KEYNAME_ALT "Alt"
1064 #define NS_DOM_KEYNAME_ALTGRAPH "AltGraph"
1065 #define NS_DOM_KEYNAME_CAPSLOCK "CapsLock"
1066 #define NS_DOM_KEYNAME_CONTROL "Control"
1067 #define NS_DOM_KEYNAME_FN "Fn"
1068 #define NS_DOM_KEYNAME_FNLOCK "FnLock"
1069 #define NS_DOM_KEYNAME_META "Meta"
1070 #define NS_DOM_KEYNAME_NUMLOCK "NumLock"
1071 #define NS_DOM_KEYNAME_SCROLLLOCK "ScrollLock"
1072 #define NS_DOM_KEYNAME_SHIFT "Shift"
1073 #define NS_DOM_KEYNAME_SYMBOL "Symbol"
1074 #define NS_DOM_KEYNAME_SYMBOLLOCK "SymbolLock"
1075 #define NS_DOM_KEYNAME_OS "OS"
1076
1077 /******************************************************************************
1078  * mozilla::Modifiers
1079  ******************************************************************************/
1080
1081 typedef uint16_t Modifiers;
1082
1083 class MOZ_STACK_CLASS GetModifiersName final : public nsAutoCString {
1084  public:
1085   explicit GetModifiersName(Modifiers aModifiers) {
1086     if (aModifiers & MODIFIER_ALT) {
1087       AssignLiteral(NS_DOM_KEYNAME_ALT);
1088     }
1089     if (aModifiers & MODIFIER_ALTGRAPH) {
1090       MaybeAppendSeparator();
1091       AppendLiteral(NS_DOM_KEYNAME_ALTGRAPH);
1092     }
1093     if (aModifiers & MODIFIER_CAPSLOCK) {
1094       MaybeAppendSeparator();
1095       AppendLiteral(NS_DOM_KEYNAME_CAPSLOCK);
1096     }
1097     if (aModifiers & MODIFIER_CONTROL) {
1098       MaybeAppendSeparator();
1099       AppendLiteral(NS_DOM_KEYNAME_CONTROL);
1100     }
1101     if (aModifiers & MODIFIER_FN) {
1102       MaybeAppendSeparator();
1103       AppendLiteral(NS_DOM_KEYNAME_FN);
1104     }
1105     if (aModifiers & MODIFIER_FNLOCK) {
1106       MaybeAppendSeparator();
1107       AppendLiteral(NS_DOM_KEYNAME_FNLOCK);
1108     }
1109     if (aModifiers & MODIFIER_META) {
1110       MaybeAppendSeparator();
1111       AppendLiteral(NS_DOM_KEYNAME_META);
1112     }
1113     if (aModifiers & MODIFIER_NUMLOCK) {
1114       MaybeAppendSeparator();
1115       AppendLiteral(NS_DOM_KEYNAME_NUMLOCK);
1116     }
1117     if (aModifiers & MODIFIER_SCROLLLOCK) {
1118       MaybeAppendSeparator();
1119       AppendLiteral(NS_DOM_KEYNAME_SCROLLLOCK);
1120     }
1121     if (aModifiers & MODIFIER_SHIFT) {
1122       MaybeAppendSeparator();
1123       AppendLiteral(NS_DOM_KEYNAME_SHIFT);
1124     }
1125     if (aModifiers & MODIFIER_SYMBOL) {
1126       MaybeAppendSeparator();
1127       AppendLiteral(NS_DOM_KEYNAME_SYMBOL);
1128     }
1129     if (aModifiers & MODIFIER_SYMBOLLOCK) {
1130       MaybeAppendSeparator();
1131       AppendLiteral(NS_DOM_KEYNAME_SYMBOLLOCK);
1132     }
1133     if (aModifiers & MODIFIER_OS) {
1134       MaybeAppendSeparator();
1135       AppendLiteral(NS_DOM_KEYNAME_OS);
1136     }
1137     if (IsEmpty()) {
1138       AssignLiteral("none");
1139     }
1140   }
1141
1142  private:
1143   void MaybeAppendSeparator() {
1144     if (!IsEmpty()) {
1145       AppendLiteral(" | ");
1146     }
1147   }
1148 };
1149
1150 /******************************************************************************
1151  * mozilla::WidgetInputEvent
1152  ******************************************************************************/
1153
1154 class WidgetInputEvent : public WidgetGUIEvent {
1155  protected:
1156   WidgetInputEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
1157                    EventClassID aEventClassID)
1158       : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, aEventClassID),
1159         mModifiers(0) {}
1160
1161   WidgetInputEvent() : mModifiers(0) {}
1162
1163  public:
1164   virtual WidgetInputEvent* AsInputEvent() override { return this; }
1165
1166   WidgetInputEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget)
1167       : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, eInputEventClass),
1168         mModifiers(0) {}
1169
1170   virtual WidgetEvent* Duplicate() const override {
1171     MOZ_ASSERT(mClass == eInputEventClass,
1172                "Duplicate() must be overridden by sub class");
1173     // Not copying widget, it is a weak reference.
1174     WidgetInputEvent* result = new WidgetInputEvent(false, mMessage, nullptr);
1175     result->AssignInputEventData(*this, true);
1176     result->mFlags = mFlags;
1177     return result;
1178   }
1179
1180   /**
1181    * Returns a modifier of "Accel" virtual modifier which is used for shortcut
1182    * key.
1183    */
1184   static Modifier AccelModifier();
1185
1186   /**
1187    * GetModifier() returns a modifier flag which is activated by aDOMKeyName.
1188    */
1189   static Modifier GetModifier(const nsAString& aDOMKeyName);
1190
1191   // true indicates the accel key on the environment is down
1192   bool IsAccel() const { return ((mModifiers & AccelModifier()) != 0); }
1193
1194   // true indicates the shift key is down
1195   bool IsShift() const { return ((mModifiers & MODIFIER_SHIFT) != 0); }
1196   // true indicates the control key is down
1197   bool IsControl() const { return ((mModifiers & MODIFIER_CONTROL) != 0); }
1198   // true indicates the alt key is down
1199   bool IsAlt() const { return ((mModifiers & MODIFIER_ALT) != 0); }
1200   // true indicates the meta key is down (or, on Mac, the Command key)
1201   bool IsMeta() const { return ((mModifiers & MODIFIER_META) != 0); }
1202   // true indicates the win key is down on Windows. Or the Super or Hyper key
1203   // is down on Linux.
1204   bool IsOS() const { return ((mModifiers & MODIFIER_OS) != 0); }
1205   // true indicates the alt graph key is down
1206   // NOTE: on Mac, the option key press causes both IsAlt() and IsAltGrpah()
1207   //       return true.
1208   bool IsAltGraph() const { return ((mModifiers & MODIFIER_ALTGRAPH) != 0); }
1209   // true indicates the CapLock LED is turn on.
1210   bool IsCapsLocked() const { return ((mModifiers & MODIFIER_CAPSLOCK) != 0); }
1211   // true indicates the NumLock LED is turn on.
1212   bool IsNumLocked() const { return ((mModifiers & MODIFIER_NUMLOCK) != 0); }
1213   // true indicates the ScrollLock LED is turn on.
1214   bool IsScrollLocked() const {
1215     return ((mModifiers & MODIFIER_SCROLLLOCK) != 0);
1216   }
1217
1218   // true indicates the Fn key is down, but this is not supported by native
1219   // key event on any platform.
1220   bool IsFn() const { return ((mModifiers & MODIFIER_FN) != 0); }
1221   // true indicates the FnLock LED is turn on, but we don't know such
1222   // keyboards nor platforms.
1223   bool IsFnLocked() const { return ((mModifiers & MODIFIER_FNLOCK) != 0); }
1224   // true indicates the Symbol is down, but this is not supported by native
1225   // key event on any platforms.
1226   bool IsSymbol() const { return ((mModifiers & MODIFIER_SYMBOL) != 0); }
1227   // true indicates the SymbolLock LED is turn on, but we don't know such
1228   // keyboards nor platforms.
1229   bool IsSymbolLocked() const {
1230     return ((mModifiers & MODIFIER_SYMBOLLOCK) != 0);
1231   }
1232
1233   void InitBasicModifiers(bool aCtrlKey, bool aAltKey, bool aShiftKey,
1234                           bool aMetaKey) {
1235     mModifiers = 0;
1236     if (aCtrlKey) {
1237       mModifiers |= MODIFIER_CONTROL;
1238     }
1239     if (aAltKey) {
1240       mModifiers |= MODIFIER_ALT;
1241     }
1242     if (aShiftKey) {
1243       mModifiers |= MODIFIER_SHIFT;
1244     }
1245     if (aMetaKey) {
1246       mModifiers |= MODIFIER_META;
1247     }
1248   }
1249
1250   Modifiers mModifiers;
1251
1252   void AssignInputEventData(const WidgetInputEvent& aEvent, bool aCopyTargets) {
1253     AssignGUIEventData(aEvent, aCopyTargets);
1254
1255     mModifiers = aEvent.mModifiers;
1256   }
1257 };
1258
1259 /******************************************************************************
1260  * mozilla::InternalUIEvent
1261  *
1262  * XXX Why this inherits WidgetGUIEvent rather than WidgetEvent?
1263  ******************************************************************************/
1264
1265 class InternalUIEvent : public WidgetGUIEvent {
1266  protected:
1267   InternalUIEvent() : mDetail(0), mCausedByUntrustedEvent(false) {}
1268
1269   InternalUIEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
1270                   EventClassID aEventClassID)
1271       : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, aEventClassID),
1272         mDetail(0),
1273         mCausedByUntrustedEvent(false) {}
1274
1275   InternalUIEvent(bool aIsTrusted, EventMessage aMessage,
1276                   EventClassID aEventClassID)
1277       : WidgetGUIEvent(aIsTrusted, aMessage, nullptr, aEventClassID),
1278         mDetail(0),
1279         mCausedByUntrustedEvent(false) {}
1280
1281  public:
1282   virtual InternalUIEvent* AsUIEvent() override { return this; }
1283
1284   /**
1285    * If the UIEvent is caused by another event (e.g., click event),
1286    * aEventCausesThisEvent should be the event.  If there is no such event,
1287    * this should be nullptr.
1288    */
1289   InternalUIEvent(bool aIsTrusted, EventMessage aMessage,
1290                   const WidgetEvent* aEventCausesThisEvent)
1291       : WidgetGUIEvent(aIsTrusted, aMessage, nullptr, eUIEventClass),
1292         mDetail(0),
1293         mCausedByUntrustedEvent(aEventCausesThisEvent &&
1294                                 !aEventCausesThisEvent->IsTrusted()) {}
1295
1296   virtual WidgetEvent* Duplicate() const override {
1297     MOZ_ASSERT(mClass == eUIEventClass,
1298                "Duplicate() must be overridden by sub class");
1299     InternalUIEvent* result = new InternalUIEvent(false, mMessage, nullptr);
1300     result->AssignUIEventData(*this, true);
1301     result->mFlags = mFlags;
1302     return result;
1303   }
1304
1305   int32_t mDetail;
1306   // mCausedByUntrustedEvent is true if the event is caused by untrusted event.
1307   bool mCausedByUntrustedEvent;
1308
1309   // If you check the event is a trusted event and NOT caused by an untrusted
1310   // event, IsTrustable() returns what you expected.
1311   bool IsTrustable() const { return IsTrusted() && !mCausedByUntrustedEvent; }
1312
1313   void AssignUIEventData(const InternalUIEvent& aEvent, bool aCopyTargets) {
1314     AssignGUIEventData(aEvent, aCopyTargets);
1315
1316     mDetail = aEvent.mDetail;
1317     mCausedByUntrustedEvent = aEvent.mCausedByUntrustedEvent;
1318   }
1319 };
1320
1321 }  // namespace mozilla
1322
1323 #endif  // mozilla_BasicEvents_h__