third_party/WebKit/Source/core/events/PointerEventFactory.h

// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef PointerEventFactory_h
#define PointerEventFactory_h

#include "core/CoreExport.h"
#include "core/events/PointerEvent.h"
#include "public/platform/WebPointerProperties.h"
#include "wtf/Allocator.h"
#include "wtf/HashMap.h"

namespace blink {

// Helper class for tracking the pointer ids for each type of PointerEvents.
// Using id re-mapping at this layer, this class makes sure that regardless of
// the domain of the id (i.e. in touch or pen) the corresponding pointer event
// will have a unique id amongst all pointer events as per pointer events'
// specification. This class intended to behave the same as existing browsers as
// much as possible for compatibility reasons. Particularly it behaves very
// similar to MS Edge to have pointer event ids generated by mouse always equal
// 1 and those that are generated by touch and pen will have increasing ids from
// 2.
class CORE_EXPORT PointerEventFactory {
    DISALLOW_NEW();
public:

    PointerEventFactory();
    ~PointerEventFactory();

    PointerEvent* create(
        const AtomicString& mouseEventName, const PlatformMouseEvent&,
        EventTarget* relatedTarget,
        LocalDOMWindow*);

    PointerEvent* create(const AtomicString& type,
        const PlatformTouchPoint&, PlatformEvent::Modifiers,
        const FloatSize& pointRadius,
        const FloatPoint& clientPoint,
        DOMWindow*);

    PointerEvent* createPointerCancelEvent(
        const int pointerId, const WebPointerProperties::PointerType);

    // For creating capture events (i.e got/lostpointercapture)
    PointerEvent* createPointerCaptureEvent(
        PointerEvent*,
        const AtomicString&);

    // For creating boundary events (i.e pointerout/leave/over/enter)
    PointerEvent* createPointerBoundaryEvent(
        PointerEvent*,
        const AtomicString&,
        EventTarget*);

    // Clear all the existing ids.
    void clear();

    // When a particular pointerId is removed, the id is considered free even
    // though there might have been other PointerEvents that were generated with
    // the same id before.
    bool remove(const int);

    // Returns all ids of the given pointerType.
    Vector<int> getPointerIdsOfType(WebPointerProperties::PointerType) const;

    // Returns whether a pointer id exists and active.
    bool isActive(const int) const;

    // Returns whether a pointer id exists and has at least one pressed button.
    bool isActiveButtonsState(const int) const;

    // Returns the id of the pointer event corresponding to the given pointer
    // properties if exists otherwise s_invalidId.
    int getPointerEventId(const WebPointerProperties&) const;

private:
    typedef WTF::UnsignedWithZeroKeyHashTraits<int> UnsignedHash;
    typedef struct IncomingId : public std::pair<int, int> {
        IncomingId() {}
        IncomingId(WebPointerProperties::PointerType pointerType,
            int rawId)
            : std::pair<int, int>(static_cast<int>(pointerType), rawId) {}
        int pointerType() const {return first;}
        int rawId() const {return second;}
    } IncomingId;
    typedef struct PointerAttributes {
        IncomingId incomingId;
        bool isActiveButtons;
        PointerAttributes() {}
        PointerAttributes(IncomingId incomingId, unsigned isActiveButtons)
        : incomingId(incomingId)
        , isActiveButtons(isActiveButtons) {}
    } PointerAttributes;

    int addIdAndActiveButtons(const IncomingId, bool isActiveButtons);
    bool isPrimary(const int) const;
    void setIdTypeButtons(PointerEventInit&, const WebPointerProperties&,
        unsigned buttons);
    void setBubblesAndCancelable(PointerEventInit&, const AtomicString& type);

    static const int s_invalidId;
    static const int s_mouseId;

    int m_currentId;
    HashMap<IncomingId, int, WTF::PairHash<int, int>, WTF::PairHashTraits<UnsignedHash, UnsignedHash>> m_pointerIncomingIdMapping;
    HashMap<int, PointerAttributes, WTF::IntHash<int>, UnsignedHash> m_pointerIdMapping;
    int m_primaryId[static_cast<int>(WebPointerProperties::PointerType::LastEntry) + 1];
    int m_idCount[static_cast<int>(WebPointerProperties::PointerType::LastEntry) + 1];
};

} // namespace blink

#endif // PointerEventFactory_h