widget/MouseEvents.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_MouseEvents_h__
   7 #define mozilla_MouseEvents_h__
   8
   9 #include <stdint.h>
  10
  11 #include "mozilla/BasicEvents.h"
  12 #include "mozilla/MathAlgorithms.h"
  13 #include "mozilla/dom/DataTransfer.h"
  14 #include "nsCOMPtr.h"
  15
  16 namespace mozilla {
  17
  18 namespace dom {
  19 class PBrowserParent;
  20 class PBrowserChild;
  21 class PBrowserBridgeParent;
  22 }  // namespace dom
  23
  24 class WidgetPointerEvent;
  25 }  // namespace mozilla
  26
  27 namespace mozilla {
  28 class WidgetPointerEventHolder final {
  29  public:
  30   nsTArray<WidgetPointerEvent> mEvents;
  31   NS_INLINE_DECL_REFCOUNTING(WidgetPointerEventHolder)
  32
  33  private:
  34   virtual ~WidgetPointerEventHolder() = default;
  35 };
  36
  37 /******************************************************************************
  38  * mozilla::WidgetPointerHelper
  39  ******************************************************************************/
  40
  41 class WidgetPointerHelper {
  42  public:
  43   uint32_t pointerId;
  44   uint32_t tiltX;
  45   uint32_t tiltY;
  46   uint32_t twist;
  47   float tangentialPressure;
  48   bool convertToPointer;
  49   RefPtr<WidgetPointerEventHolder> mCoalescedWidgetEvents;
  50
  51   WidgetPointerHelper()
  52       : pointerId(0),
  53         tiltX(0),
  54         tiltY(0),
  55         twist(0),
  56         tangentialPressure(0),
  57         convertToPointer(true) {}
  58
  59   WidgetPointerHelper(uint32_t aPointerId, uint32_t aTiltX, uint32_t aTiltY,
  60                       uint32_t aTwist = 0, float aTangentialPressure = 0)
  61       : pointerId(aPointerId),
  62         tiltX(aTiltX),
  63         tiltY(aTiltY),
  64         twist(aTwist),
  65         tangentialPressure(aTangentialPressure),
  66         convertToPointer(true) {}
  67
  68   explicit WidgetPointerHelper(const WidgetPointerHelper& aHelper) = default;
  69
  70   void AssignPointerHelperData(const WidgetPointerHelper& aEvent,
  71                                bool aCopyCoalescedEvents = false) {
  72     pointerId = aEvent.pointerId;
  73     tiltX = aEvent.tiltX;
  74     tiltY = aEvent.tiltY;
  75     twist = aEvent.twist;
  76     tangentialPressure = aEvent.tangentialPressure;
  77     convertToPointer = aEvent.convertToPointer;
  78     if (aCopyCoalescedEvents) {
  79       mCoalescedWidgetEvents = aEvent.mCoalescedWidgetEvents;
  80     }
  81   }
  82 };
  83
  84 /******************************************************************************
  85  * mozilla::WidgetMouseEventBase
  86  ******************************************************************************/
  87
  88 class WidgetMouseEventBase : public WidgetInputEvent {
  89  private:
  90   friend class dom::PBrowserParent;
  91   friend class dom::PBrowserChild;
  92   friend class dom::PBrowserBridgeParent;
  93
  94  protected:
  95   WidgetMouseEventBase()
  96       : mPressure(0),
  97         mButton(0),
  98         mButtons(0),
  99         mInputSource(/* MouseEvent_Binding::MOZ_SOURCE_MOUSE = */ 1) {}
 100   // Including MouseEventBinding.h here leads to an include loop, so
 101   // we have to hardcode MouseEvent_Binding::MOZ_SOURCE_MOUSE.
 102
 103   WidgetMouseEventBase(bool aIsTrusted, EventMessage aMessage,
 104                        nsIWidget* aWidget, EventClassID aEventClassID)
 105       : WidgetInputEvent(aIsTrusted, aMessage, aWidget, aEventClassID),
 106         mPressure(0),
 107         mButton(0),
 108         mButtons(0),
 109         mInputSource(/* MouseEvent_Binding::MOZ_SOURCE_MOUSE = */ 1) {}
 110   // Including MouseEventBinding.h here leads to an include loop, so
 111   // we have to hardcode MouseEvent_Binding::MOZ_SOURCE_MOUSE.
 112
 113  public:
 114   virtual WidgetMouseEventBase* AsMouseEventBase() override { return this; }
 115
 116   virtual WidgetEvent* Duplicate() const override {
 117     MOZ_CRASH("WidgetMouseEventBase must not be most-subclass");
 118   }
 119
 120   // ID of the canvas HitRegion
 121   nsString mRegion;
 122
 123   // Finger or touch pressure of event. It ranges between 0.0 and 1.0.
 124   float mPressure;
 125
 126   // Pressed button ID of mousedown or mouseup event.
 127   // This is set only when pressing a button causes the event.
 128   int16_t mButton;
 129
 130   // Flags of all pressed buttons at the event fired.
 131   // This is set at any mouse event, don't be confused with |mButton|.
 132   int16_t mButtons;
 133
 134   // Possible values a in MouseEvent
 135   uint16_t mInputSource;
 136
 137   bool IsLeftButtonPressed() const {
 138     return !!(mButtons & MouseButtonsFlag::ePrimaryFlag);
 139   }
 140   bool IsRightButtonPressed() const {
 141     return !!(mButtons & MouseButtonsFlag::eSecondaryFlag);
 142   }
 143   bool IsMiddleButtonPressed() const {
 144     return !!(mButtons & MouseButtonsFlag::eMiddleFlag);
 145   }
 146   bool Is4thButtonPressed() const {
 147     return !!(mButtons & MouseButtonsFlag::e4thFlag);
 148   }
 149   bool Is5thButtonPressed() const {
 150     return !!(mButtons & MouseButtonsFlag::e5thFlag);
 151   }
 152
 153   void AssignMouseEventBaseData(const WidgetMouseEventBase& aEvent,
 154                                 bool aCopyTargets) {
 155     AssignInputEventData(aEvent, aCopyTargets);
 156
 157     mButton = aEvent.mButton;
 158     mButtons = aEvent.mButtons;
 159     mPressure = aEvent.mPressure;
 160     mInputSource = aEvent.mInputSource;
 161   }
 162
 163   /**
 164    * Returns true if left click event.
 165    */
 166   bool IsLeftClickEvent() const {
 167     return mMessage == eMouseClick && mButton == MouseButton::ePrimary;
 168   }
 169 };
 170
 171 /******************************************************************************
 172  * mozilla::WidgetMouseEvent
 173  ******************************************************************************/
 174
 175 class WidgetMouseEvent : public WidgetMouseEventBase,
 176                          public WidgetPointerHelper {
 177  private:
 178   friend class dom::PBrowserParent;
 179   friend class dom::PBrowserChild;
 180   friend class dom::PBrowserBridgeParent;
 181
 182  public:
 183   typedef bool ReasonType;
 184   enum Reason : ReasonType { eReal, eSynthesized };
 185
 186   typedef uint8_t ContextMenuTriggerType;
 187   enum ContextMenuTrigger : ContextMenuTriggerType {
 188     eNormal,
 189     eContextMenuKey,
 190     eControlClick
 191   };
 192
 193   typedef uint8_t ExitFromType;
 194   enum ExitFrom : ExitFromType {
 195     ePlatformChild,
 196     ePlatformTopLevel,
 197     ePuppet,
 198     ePuppetParentToPuppetChild
 199   };
 200
 201  protected:
 202   WidgetMouseEvent()
 203       : mReason(eReal),
 204         mContextMenuTrigger(eNormal),
 205         mClickCount(0),
 206         mIgnoreRootScrollFrame(false),
 207         mUseLegacyNonPrimaryDispatch(false),
 208         mClickEventPrevented(false) {}
 209
 210   WidgetMouseEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
 211                    EventClassID aEventClassID, Reason aReason)
 212       : WidgetMouseEventBase(aIsTrusted, aMessage, aWidget, aEventClassID),
 213         mReason(aReason),
 214         mContextMenuTrigger(eNormal),
 215         mClickCount(0),
 216         mIgnoreRootScrollFrame(false),
 217         mUseLegacyNonPrimaryDispatch(false),
 218         mClickEventPrevented(false) {}
 219
 220 #ifdef DEBUG
 221   void AssertContextMenuEventButtonConsistency() const;
 222 #endif
 223
 224  public:
 225   virtual WidgetMouseEvent* AsMouseEvent() override { return this; }
 226
 227   WidgetMouseEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
 228                    Reason aReason,
 229                    ContextMenuTrigger aContextMenuTrigger = eNormal)
 230       : WidgetMouseEventBase(aIsTrusted, aMessage, aWidget, eMouseEventClass),
 231         mReason(aReason),
 232         mContextMenuTrigger(aContextMenuTrigger),
 233         mClickCount(0),
 234         mIgnoreRootScrollFrame(false),
 235         mUseLegacyNonPrimaryDispatch(false),
 236         mClickEventPrevented(false) {
 237     if (aMessage == eContextMenu) {
 238       mButton = (mContextMenuTrigger == eNormal) ? MouseButton::eSecondary
 239                                                  : MouseButton::ePrimary;
 240     }
 241   }
 242
 243 #ifdef DEBUG
 244   virtual ~WidgetMouseEvent() { AssertContextMenuEventButtonConsistency(); }
 245 #endif
 246
 247   virtual WidgetEvent* Duplicate() const override {
 248     MOZ_ASSERT(mClass == eMouseEventClass,
 249                "Duplicate() must be overridden by sub class");
 250     // Not copying widget, it is a weak reference.
 251     WidgetMouseEvent* result = new WidgetMouseEvent(
 252         false, mMessage, nullptr, mReason, mContextMenuTrigger);
 253     result->AssignMouseEventData(*this, true);
 254     result->mFlags = mFlags;
 255     return result;
 256   }
 257
 258   // If during mouseup handling we detect that click event might need to be
 259   // dispatched, this is setup to be the target of the click event.
 260   nsCOMPtr<dom::EventTarget> mClickTarget;
 261
 262   // mReason indicates the reason why the event is fired:
 263   // - Representing mouse operation.
 264   // - Synthesized for emulating mousemove event when the content under the
 265   //   mouse cursor is scrolled.
 266   Reason mReason;
 267
 268   // mContextMenuTrigger is valid only when mMessage is eContextMenu.
 269   // This indicates if the context menu event is caused by context menu key or
 270   // other reasons (typically, a click of right mouse button).
 271   ContextMenuTrigger mContextMenuTrigger;
 272
 273   // mExitFrom contains a value only when mMessage is eMouseExitFromWidget.
 274   // This indicates if the mouse cursor exits from a top level platform widget,
 275   // a child widget or a puppet widget.
 276   Maybe<ExitFrom> mExitFrom;
 277
 278   // mClickCount may be non-zero value when mMessage is eMouseDown, eMouseUp,
 279   // eMouseClick or eMouseDoubleClick. The number is count of mouse clicks.
 280   // Otherwise, this must be 0.
 281   uint32_t mClickCount;
 282
 283   // Whether the event should ignore scroll frame bounds during dispatch.
 284   bool mIgnoreRootScrollFrame;
 285
 286   // Indicates whether the event should dispatch click events for non-primary
 287   // mouse buttons on window and document.
 288   bool mUseLegacyNonPrimaryDispatch;
 289
 290   // Whether the event shouldn't cause click event.
 291   bool mClickEventPrevented;
 292
 293   void AssignMouseEventData(const WidgetMouseEvent& aEvent, bool aCopyTargets) {
 294     AssignMouseEventBaseData(aEvent, aCopyTargets);
 295     AssignPointerHelperData(aEvent, /* aCopyCoalescedEvents */ true);
 296
 297     mExitFrom = aEvent.mExitFrom;
 298     mClickCount = aEvent.mClickCount;
 299     mIgnoreRootScrollFrame = aEvent.mIgnoreRootScrollFrame;
 300     mUseLegacyNonPrimaryDispatch = aEvent.mUseLegacyNonPrimaryDispatch;
 301     mClickEventPrevented = aEvent.mClickEventPrevented;
 302   }
 303
 304   /**
 305    * Returns true if the event is a context menu event caused by key.
 306    */
 307   bool IsContextMenuKeyEvent() const {
 308     return mMessage == eContextMenu && mContextMenuTrigger == eContextMenuKey;
 309   }
 310
 311   /**
 312    * Returns true if the event is a real mouse event.  Otherwise, i.e., it's
 313    * a synthesized event by scroll or something, returns false.
 314    */
 315   bool IsReal() const { return mReason == eReal; }
 316
 317   /**
 318    * Returns true if middle click paste is enabled.
 319    */
 320   static bool IsMiddleClickPasteEnabled();
 321 };
 322
 323 /******************************************************************************
 324  * mozilla::WidgetDragEvent
 325  ******************************************************************************/
 326
 327 class WidgetDragEvent : public WidgetMouseEvent {
 328  private:
 329   friend class mozilla::dom::PBrowserParent;
 330   friend class mozilla::dom::PBrowserChild;
 331
 332  protected:
 333   WidgetDragEvent()
 334       : mUserCancelled(false), mDefaultPreventedOnContent(false) {}
 335
 336  public:
 337   virtual WidgetDragEvent* AsDragEvent() override { return this; }
 338
 339   WidgetDragEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget)
 340       : WidgetMouseEvent(aIsTrusted, aMessage, aWidget, eDragEventClass, eReal),
 341         mUserCancelled(false),
 342         mDefaultPreventedOnContent(false) {}
 343
 344   virtual WidgetEvent* Duplicate() const override {
 345     MOZ_ASSERT(mClass == eDragEventClass,
 346                "Duplicate() must be overridden by sub class");
 347     // Not copying widget, it is a weak reference.
 348     WidgetDragEvent* result = new WidgetDragEvent(false, mMessage, nullptr);
 349     result->AssignDragEventData(*this, true);
 350     result->mFlags = mFlags;
 351     return result;
 352   }
 353
 354   // The dragging data.
 355   nsCOMPtr<dom::DataTransfer> mDataTransfer;
 356
 357   // If this is true, user has cancelled the drag operation.
 358   bool mUserCancelled;
 359   // If this is true, the drag event's preventDefault() is called on content.
 360   bool mDefaultPreventedOnContent;
 361
 362   // XXX Not tested by test_assign_event_data.html
 363   void AssignDragEventData(const WidgetDragEvent& aEvent, bool aCopyTargets) {
 364     AssignMouseEventData(aEvent, aCopyTargets);
 365
 366     mDataTransfer = aEvent.mDataTransfer;
 367     // XXX mUserCancelled isn't copied, is this intentionally?
 368     mUserCancelled = false;
 369     mDefaultPreventedOnContent = aEvent.mDefaultPreventedOnContent;
 370   }
 371
 372   /**
 373    * Should be called before dispatching the DOM tree if this event is
 374    * synthesized for tests because drop effect is initialized before
 375    * dispatching from widget if it's not synthesized event, but synthesized
 376    * events are not initialized in the path.
 377    */
 378   void InitDropEffectForTests();
 379 };
 380
 381 /******************************************************************************
 382  * mozilla::WidgetMouseScrollEvent
 383  *
 384  * This is used for legacy DOM mouse scroll events, i.e.,
 385  * DOMMouseScroll and MozMousePixelScroll event.  These events are NOT hanbled
 386  * by ESM even if widget dispatches them.  Use new WidgetWheelEvent instead.
 387  ******************************************************************************/
 388
 389 class WidgetMouseScrollEvent : public WidgetMouseEventBase {
 390  private:
 391   WidgetMouseScrollEvent() : mDelta(0), mIsHorizontal(false) {}
 392
 393  public:
 394   virtual WidgetMouseScrollEvent* AsMouseScrollEvent() override { return this; }
 395
 396   WidgetMouseScrollEvent(bool aIsTrusted, EventMessage aMessage,
 397                          nsIWidget* aWidget)
 398       : WidgetMouseEventBase(aIsTrusted, aMessage, aWidget,
 399                              eMouseScrollEventClass),
 400         mDelta(0),
 401         mIsHorizontal(false) {}
 402
 403   virtual WidgetEvent* Duplicate() const override {
 404     MOZ_ASSERT(mClass == eMouseScrollEventClass,
 405                "Duplicate() must be overridden by sub class");
 406     // Not copying widget, it is a weak reference.
 407     WidgetMouseScrollEvent* result =
 408         new WidgetMouseScrollEvent(false, mMessage, nullptr);
 409     result->AssignMouseScrollEventData(*this, true);
 410     result->mFlags = mFlags;
 411     return result;
 412   }
 413
 414   // The delta value of mouse scroll event.
 415   // If the event message is eLegacyMouseLineOrPageScroll, the value indicates
 416   // scroll amount in lines.  However, if the value is
 417   // UIEvent::SCROLL_PAGE_UP or UIEvent::SCROLL_PAGE_DOWN, the
 418   // value inducates one page scroll.  If the event message is
 419   // eLegacyMousePixelScroll, the value indicates scroll amount in pixels.
 420   int32_t mDelta;
 421
 422   // If this is true, it may cause to scroll horizontally.
 423   // Otherwise, vertically.
 424   bool mIsHorizontal;
 425
 426   void AssignMouseScrollEventData(const WidgetMouseScrollEvent& aEvent,
 427                                   bool aCopyTargets) {
 428     AssignMouseEventBaseData(aEvent, aCopyTargets);
 429
 430     mDelta = aEvent.mDelta;
 431     mIsHorizontal = aEvent.mIsHorizontal;
 432   }
 433 };
 434
 435 /******************************************************************************
 436  * mozilla::WidgetWheelEvent
 437  ******************************************************************************/
 438
 439 class WidgetWheelEvent : public WidgetMouseEventBase {
 440  private:
 441   friend class mozilla::dom::PBrowserParent;
 442   friend class mozilla::dom::PBrowserChild;
 443
 444   WidgetWheelEvent()
 445       : mDeltaX(0.0),
 446         mDeltaY(0.0),
 447         mDeltaZ(0.0),
 448         mOverflowDeltaX(0.0),
 449         mOverflowDeltaY(0.0)
 450         // Including WheelEventBinding.h here leads to an include loop, so
 451         // we have to hardcode WheelEvent_Binding::DOM_DELTA_PIXEL.
 452         ,
 453         mDeltaMode(/* WheelEvent_Binding::DOM_DELTA_PIXEL = */ 0),
 454         mLineOrPageDeltaX(0),
 455         mLineOrPageDeltaY(0),
 456         mScrollType(SCROLL_DEFAULT),
 457         mCustomizedByUserPrefs(false),
 458         mMayHaveMomentum(false),
 459         mIsMomentum(false),
 460         mIsNoLineOrPageDelta(false),
 461         mViewPortIsOverscrolled(false),
 462         mCanTriggerSwipe(false),
 463         mAllowToOverrideSystemScrollSpeed(false),
 464         mDeltaValuesHorizontalizedForDefaultHandler(false) {}
 465
 466  public:
 467   virtual WidgetWheelEvent* AsWheelEvent() override { return this; }
 468
 469   WidgetWheelEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget)
 470       : WidgetMouseEventBase(aIsTrusted, aMessage, aWidget, eWheelEventClass),
 471         mDeltaX(0.0),
 472         mDeltaY(0.0),
 473         mDeltaZ(0.0),
 474         mOverflowDeltaX(0.0),
 475         mOverflowDeltaY(0.0)
 476         // Including WheelEventBinding.h here leads to an include loop, so
 477         // we have to hardcode WheelEvent_Binding::DOM_DELTA_PIXEL.
 478         ,
 479         mDeltaMode(/* WheelEvent_Binding::DOM_DELTA_PIXEL = */ 0),
 480         mLineOrPageDeltaX(0),
 481         mLineOrPageDeltaY(0),
 482         mScrollType(SCROLL_DEFAULT),
 483         mCustomizedByUserPrefs(false),
 484         mMayHaveMomentum(false),
 485         mIsMomentum(false),
 486         mIsNoLineOrPageDelta(false),
 487         mViewPortIsOverscrolled(false),
 488         mCanTriggerSwipe(false),
 489         mAllowToOverrideSystemScrollSpeed(true),
 490         mDeltaValuesHorizontalizedForDefaultHandler(false) {}
 491
 492   virtual WidgetEvent* Duplicate() const override {
 493     MOZ_ASSERT(mClass == eWheelEventClass,
 494                "Duplicate() must be overridden by sub class");
 495     // Not copying widget, it is a weak reference.
 496     WidgetWheelEvent* result = new WidgetWheelEvent(false, mMessage, nullptr);
 497     result->AssignWheelEventData(*this, true);
 498     result->mFlags = mFlags;
 499     return result;
 500   }
 501
 502   // On OS X, scroll gestures that start at the edge of the scrollable range
 503   // can result in a swipe gesture. For the first wheel event of such a
 504   // gesture, call TriggersSwipe() after the event has been processed
 505   // in order to find out whether a swipe should be started.
 506   bool TriggersSwipe() const {
 507     return mCanTriggerSwipe && mViewPortIsOverscrolled &&
 508            this->mOverflowDeltaX != 0.0;
 509   }
 510
 511   // NOTE: mDeltaX, mDeltaY and mDeltaZ may be customized by
 512   //       mousewheel.*.delta_multiplier_* prefs which are applied by
 513   //       EventStateManager.  So, after widget dispatches this event,
 514   //       these delta values may have different values than before.
 515   double mDeltaX;
 516   double mDeltaY;
 517   double mDeltaZ;
 518
 519   enum class DeltaModeCheckingState : uint8_t {
 520     // Neither deltaMode nor the delta values have been accessed.
 521     Unknown,
 522     // The delta values have been accessed, without checking deltaMode first.
 523     Unchecked,
 524     // The deltaMode has been checked.
 525     Checked,
 526   };
 527
 528   // For compat reasons, we might expose a DOM_DELTA_LINE event as
 529   // DOM_DELTA_PIXEL instead. Whether we do that depends on whether the event
 530   // has been asked for the deltaMode before the deltas. If it has, we assume
 531   // that the page will correctly handle DOM_DELTA_LINE. This variable tracks
 532   // that state. See bug 1392460.
 533   DeltaModeCheckingState mDeltaModeCheckingState =
 534       DeltaModeCheckingState::Unknown;
 535
 536   // The amount of scrolling per line or page, without accounting for mouse
 537   // wheel transactions etc.
 538   //
 539   // Computed by EventStateManager::DeltaAccumulator::InitLineOrPageDelta.
 540   nsSize mScrollAmount;
 541
 542   // overflowed delta values for scroll, these values are set by
 543   // EventStateManger.  If the default action of the wheel event isn't scroll,
 544   // these values are always zero.  Otherwise, remaining delta values which are
 545   // not used by scroll are set.
 546   // NOTE: mDeltaX, mDeltaY and mDeltaZ may be modified by EventStateManager.
 547   //       However, mOverflowDeltaX and mOverflowDeltaY indicate unused original
 548   //       delta values which are not applied the delta_multiplier prefs.
 549   //       So, if widget wanted to know the actual direction to be scrolled,
 550   //       it would need to check the mDeltaX and mDeltaY.
 551   double mOverflowDeltaX;
 552   double mOverflowDeltaY;
 553
 554   // Should be one of WheelEvent_Binding::DOM_DELTA_*
 555   uint32_t mDeltaMode;
 556
 557   // If widget sets mLineOrPageDelta, EventStateManager will dispatch
 558   // eLegacyMouseLineOrPageScroll event for compatibility.  Note that the delta
 559   // value means pages if the mDeltaMode is DOM_DELTA_PAGE, otherwise, lines.
 560   int32_t mLineOrPageDeltaX;
 561   int32_t mLineOrPageDeltaY;
 562
 563   // When the default action for an wheel event is moving history or zooming,
 564   // need to chose a delta value for doing it.
 565   int32_t GetPreferredIntDelta() {
 566     if (!mLineOrPageDeltaX && !mLineOrPageDeltaY) {
 567       return 0;
 568     }
 569     if (mLineOrPageDeltaY && !mLineOrPageDeltaX) {
 570       return mLineOrPageDeltaY;
 571     }
 572     if (mLineOrPageDeltaX && !mLineOrPageDeltaY) {
 573       return mLineOrPageDeltaX;
 574     }
 575     if ((mLineOrPageDeltaX < 0 && mLineOrPageDeltaY > 0) ||
 576         (mLineOrPageDeltaX > 0 && mLineOrPageDeltaY < 0)) {
 577       return 0;  // We cannot guess the answer in this case.
 578     }
 579     return (Abs(mLineOrPageDeltaX) > Abs(mLineOrPageDeltaY))
 580                ? mLineOrPageDeltaX
 581                : mLineOrPageDeltaY;
 582   }
 583
 584   // Scroll type
 585   // The default value is SCROLL_DEFAULT, which means EventStateManager will
 586   // select preferred scroll type automatically.
 587   enum ScrollType : uint8_t {
 588     SCROLL_DEFAULT,
 589     SCROLL_SYNCHRONOUSLY,
 590     SCROLL_ASYNCHRONOUSELY,
 591     SCROLL_SMOOTHLY
 592   };
 593   ScrollType mScrollType;
 594
 595   // If the delta values are computed from prefs, this value is true.
 596   // Otherwise, i.e., they are computed from native events, false.
 597   bool mCustomizedByUserPrefs;
 598
 599   // true if the momentum events directly tied to this event may follow it.
 600   bool mMayHaveMomentum;
 601   // true if the event is caused by momentum.
 602   bool mIsMomentum;
 603
 604   // If device event handlers don't know when they should set mLineOrPageDeltaX
 605   // and mLineOrPageDeltaY, this is true.  Otherwise, false.
 606   // If mIsNoLineOrPageDelta is true, ESM will generate
 607   // eLegacyMouseLineOrPageScroll events when accumulated delta values reach
 608   // a line height.
 609   bool mIsNoLineOrPageDelta;
 610
 611   // Whether or not the parent of the currently overscrolled frame is the
 612   // ViewPort. This is false in situations when an element on the page is being
 613   // overscrolled (such as a text field), but true when the 'page' is being
 614   // overscrolled.
 615   bool mViewPortIsOverscrolled;
 616
 617   // The wheel event can trigger a swipe to start if it's overscrolling the
 618   // viewport.
 619   bool mCanTriggerSwipe;
 620
 621   // If mAllowToOverrideSystemScrollSpeed is true, the scroll speed may be
 622   // overridden.  Otherwise, the scroll speed won't be overridden even if
 623   // it's enabled by the pref.
 624   bool mAllowToOverrideSystemScrollSpeed;
 625
 626   // After the event's default action handler has adjusted its delta's values
 627   // for horizontalizing a vertical wheel scroll, this variable will be set to
 628   // true.
 629   bool mDeltaValuesHorizontalizedForDefaultHandler;
 630
 631   void AssignWheelEventData(const WidgetWheelEvent& aEvent, bool aCopyTargets) {
 632     AssignMouseEventBaseData(aEvent, aCopyTargets);
 633
 634     mDeltaX = aEvent.mDeltaX;
 635     mDeltaY = aEvent.mDeltaY;
 636     mDeltaZ = aEvent.mDeltaZ;
 637     mDeltaMode = aEvent.mDeltaMode;
 638     mScrollAmount = aEvent.mScrollAmount;
 639     mCustomizedByUserPrefs = aEvent.mCustomizedByUserPrefs;
 640     mMayHaveMomentum = aEvent.mMayHaveMomentum;
 641     mIsMomentum = aEvent.mIsMomentum;
 642     mIsNoLineOrPageDelta = aEvent.mIsNoLineOrPageDelta;
 643     mLineOrPageDeltaX = aEvent.mLineOrPageDeltaX;
 644     mLineOrPageDeltaY = aEvent.mLineOrPageDeltaY;
 645     mScrollType = aEvent.mScrollType;
 646     mOverflowDeltaX = aEvent.mOverflowDeltaX;
 647     mOverflowDeltaY = aEvent.mOverflowDeltaY;
 648     mViewPortIsOverscrolled = aEvent.mViewPortIsOverscrolled;
 649     mCanTriggerSwipe = aEvent.mCanTriggerSwipe;
 650     mAllowToOverrideSystemScrollSpeed =
 651         aEvent.mAllowToOverrideSystemScrollSpeed;
 652     mDeltaValuesHorizontalizedForDefaultHandler =
 653         aEvent.mDeltaValuesHorizontalizedForDefaultHandler;
 654   }
 655
 656   // System scroll speed settings may be too slow at using Gecko.  In such
 657   // case, we should override the scroll speed computed with system settings.
 658   // Following methods return preferred delta values which are multiplied by
 659   // factors specified by prefs.  If system scroll speed shouldn't be
 660   // overridden (e.g., this feature is disabled by pref), they return raw
 661   // delta values.
 662   double OverriddenDeltaX() const;
 663   double OverriddenDeltaY() const;
 664
 665   // Compute the overridden delta value.  This may be useful for suppressing
 666   // too fast scroll by system scroll speed overriding when widget sets
 667   // mAllowToOverrideSystemScrollSpeed.
 668   static double ComputeOverriddenDelta(double aDelta, bool aIsForVertical);
 669
 670  private:
 671   static bool sInitialized;
 672   static bool sIsSystemScrollSpeedOverrideEnabled;
 673   static int32_t sOverrideFactorX;
 674   static int32_t sOverrideFactorY;
 675   static void Initialize();
 676 };
 677
 678 /******************************************************************************
 679  * mozilla::WidgetPointerEvent
 680  ******************************************************************************/
 681
 682 class WidgetPointerEvent : public WidgetMouseEvent {
 683   friend class mozilla::dom::PBrowserParent;
 684   friend class mozilla::dom::PBrowserChild;
 685
 686   WidgetPointerEvent()
 687       : mWidth(1), mHeight(1), mIsPrimary(true), mFromTouchEvent(false) {}
 688
 689  public:
 690   virtual WidgetPointerEvent* AsPointerEvent() override { return this; }
 691
 692   WidgetPointerEvent(bool aIsTrusted, EventMessage aMsg, nsIWidget* w)
 693       : WidgetMouseEvent(aIsTrusted, aMsg, w, ePointerEventClass, eReal),
 694         mWidth(1),
 695         mHeight(1),
 696         mIsPrimary(true),
 697         mFromTouchEvent(false) {}
 698
 699   explicit WidgetPointerEvent(const WidgetMouseEvent& aEvent)
 700       : WidgetMouseEvent(aEvent),
 701         mWidth(1),
 702         mHeight(1),
 703         mIsPrimary(true),
 704         mFromTouchEvent(false) {
 705     mClass = ePointerEventClass;
 706   }
 707
 708   virtual WidgetEvent* Duplicate() const override {
 709     MOZ_ASSERT(mClass == ePointerEventClass,
 710                "Duplicate() must be overridden by sub class");
 711     // Not copying widget, it is a weak reference.
 712     WidgetPointerEvent* result =
 713         new WidgetPointerEvent(false, mMessage, nullptr);
 714     result->AssignPointerEventData(*this, true);
 715     result->mFlags = mFlags;
 716     return result;
 717   }
 718
 719   uint32_t mWidth;
 720   uint32_t mHeight;
 721   bool mIsPrimary;
 722   bool mFromTouchEvent;
 723
 724   // XXX Not tested by test_assign_event_data.html
 725   void AssignPointerEventData(const WidgetPointerEvent& aEvent,
 726                               bool aCopyTargets) {
 727     AssignMouseEventData(aEvent, aCopyTargets);
 728
 729     mWidth = aEvent.mWidth;
 730     mHeight = aEvent.mHeight;
 731     mIsPrimary = aEvent.mIsPrimary;
 732     mFromTouchEvent = aEvent.mFromTouchEvent;
 733   }
 734 };
 735
 736 }  // namespace mozilla
 737
 738 #endif  // mozilla_MouseEvents_h__