iOS WebCore的WebEvent和EventHandler

WebEvent是iOS专有的类，负责封装和携带从UIKit得到的系统事件信息，并由WebKit层的WAKResponder子类传递到WebCore的EventHandler。

开源码中WebEvent的声明为：

[cpp] typedef enum {
    WebEventMouseDown,
    WebEventMouseUp,
    WebEventMouseMoved,

    WebEventScrollWheel,

    WebEventKeyDown,
    WebEventKeyUp,

    WebEventTouchBegin,
    WebEventTouchChange,
    WebEventTouchEnd,
    WebEventTouchCancel
} WebEventType;

typedef enum {
    WebEventTouchPhaseBegan,
    WebEventTouchPhaseMoved,
    WebEventTouchPhaseStationary,
    WebEventTouchPhaseEnded,
    WebEventTouchPhaseCancelled
} WebEventTouchPhaseType;

// These enum values are copied directly from GSEvent for compatibility.
typedef enum
{
    WebEventFlagMaskAlphaShift = 0x00010000,
    WebEventFlagMaskShift      = 0x00020000,
    WebEventFlagMaskControl    = 0x00040000,
    WebEventFlagMaskAlternate = 0x00080000,
    WebEventFlagMaskCommand    = 0x00100000,
} WebEventFlagValues;
typedef unsigned WebEventFlags;

// These enum values are copied directly from GSEvent for compatibility.
typedef enum
{
    WebEventCharacterSetASCII           = 0,
    WebEventCharacterSetSymbol          = 1,
    WebEventCharacterSetDingbats        = 2,
    WebEventCharacterSetUnicode         = 253,
    WebEventCharacterSetFunctionKeys    = 254,
} WebEventCharacterSet;

@inte易做图ce WebEvent : NSObject {
@private
    WebEventType _type;
    CFTimeInterval _timestamp;

    CGPoint _locationInWindow;

    NSString *_characters;
    NSString *_charactersIgnoringModifiers;
    WebEventFlags _modifierFlags;
    BOOL _keyRepeating;
    BOOL _popupVariant;
    uint16_t _keyCode;
    BOOL _tabKey;
    WebEventCharacterSet _characterSet;

    float _deltaX;
    float _deltaY;

    unsigned _touchCount;
    NSArray *_touchLocations;
    NSArray *_touchIdentifiers;
    NSArray *_touchPhases;

    BOOL _isGesture;
    float _gestureScale;
    float _gestureRotation;
}

- (WebEvent *)initWithMouseEventType:(WebEventType)type
                           timeStamp:(CFTimeInterval)timeStamp
                            location:(CGPoint)point;

- (WebEvent *)initWithScrollWheelEventWithTimeStamp:(CFTimeInterval)timeStamp
                                           location:(CGPoint)point
                                              deltaX:(float)deltaX
                                              deltaY:(float)deltaY;

- (WebEvent *)initWithTouchEventType:(WebEventType)type
                           timeStamp:(CFTimeInterval)timeStamp
                            location:(CGPoint)point
                           modifiers:(WebEventFlags)modifiers
                          touchCount:(unsigned)touchCount
                      touchLocations:(NSArray *)touchLocations
                    touchIdentifiers:(NSArray *)touchIdentifiers
                         touchPhases:(NSArray *)touchPhases isGesture:(BOOL)isGesture
                        gestureScale:(float)gestureScale
                     gestureRotation:(float)gestureRotation;

- (WebEvent *)initWithKeyEventType:(WebEventType)type
                         timeStamp:(CFTimeInterval)timeStamp
                        characters:(NSString *)characters
       charactersIgnoringModifiers:(NSString *)charactersIgnoringModifiers
                         modifiers:(WebEventFlag

补充：移动开发 , IOS ,