ref: 1d50aea6c14615b107116dac70e71454099ece5d
dir: /domino/domino-lib/EventTarget.js/
"use strict";
var Event = require('./Event');
var MouseEvent = require('./MouseEvent');
var utils = require('./utils');
module.exports = EventTarget;
function EventTarget() {}
EventTarget.prototype = {
// XXX
// See WebIDL §4.8 for details on object event handlers
// and how they should behave. We actually have to accept
// any object to addEventListener... Can't type check it.
// on registration.
// XXX:
// Capturing event listeners are sort of rare. I think I can optimize
// them so that dispatchEvent can skip the capturing phase (or much of
// it). Each time a capturing listener is added, increment a flag on
// the target node and each of its ancestors. Decrement when removed.
// And update the counter when nodes are added and removed from the
// tree as well. Then, in dispatch event, the capturing phase can
// abort if it sees any node with a zero count.
addEventListener: function addEventListener(type, listener, capture) {
if (!listener) return;
if (capture === undefined) capture = false;
if (!this._listeners) this._listeners = Object.create(null);
if (!this._listeners[type]) this._listeners[type] = [];
var list = this._listeners[type];
// If this listener has already been registered, just return
for(var i = 0, n = list.length; i < n; i++) {
var l = list[i];
if (l.listener === listener && l.capture === capture)
return;
}
// Add an object to the list of listeners
var obj = { listener: listener, capture: capture };
if (typeof listener === 'function') obj.f = listener;
list.push(obj);
},
removeEventListener: function removeEventListener(type,
listener,
capture) {
if (capture === undefined) capture = false;
if (this._listeners) {
var list = this._listeners[type];
if (list) {
// Find the listener in the list and remove it
for(var i = 0, n = list.length; i < n; i++) {
var l = list[i];
if (l.listener === listener && l.capture === capture) {
if (list.length === 1) {
this._listeners[type] = undefined;
}
else {
list.splice(i, 1);
}
return;
}
}
}
}
},
// This is the public API for dispatching untrusted public events.
// See _dispatchEvent for the implementation
dispatchEvent: function dispatchEvent(event) {
// Dispatch an untrusted event
return this._dispatchEvent(event, false);
},
//
// See DOMCore §4.4
// XXX: I'll probably need another version of this method for
// internal use, one that does not set isTrusted to false.
// XXX: see Document._dispatchEvent: perhaps that and this could
// call a common internal function with different settings of
// a trusted boolean argument
//
// XXX:
// The spec has changed in how to deal with handlers registered
// on idl or content attributes rather than with addEventListener.
// Used to say that they always ran first. That's how webkit does it
// Spec now says that they run in a position determined by
// when they were first set. FF does it that way. See:
// http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#event-handlers
//
_dispatchEvent: function _dispatchEvent(event, trusted) {
if (typeof trusted !== 'boolean') trusted = false;
function invoke(target, event) {
var type = event.type, phase = event.eventPhase;
event.currentTarget = target;
// If there was an individual handler defined, invoke it first
// XXX: see comment above: this shouldn't always be first.
if (phase !== Event.CAPTURING_PHASE &&
target._handlers && target._handlers[type])
{
var handler = target._handlers[type];
var rv;
if (typeof handler === 'function') {
rv=handler.call(event.currentTarget, event);
}
else {
var f = handler.handleEvent;
if (typeof f !== 'function')
throw new TypeError('handleEvent property of ' +
'event handler object is' +
'not a function.');
rv=f.call(handler, event);
}
switch(event.type) {
case 'mouseover':
if (rv === true) // Historical baggage
event.preventDefault();
break;
case 'beforeunload':
// XXX: eventually we need a special case here
/* falls through */
default:
if (rv === false)
event.preventDefault();
break;
}
}
// Now invoke list list of listeners for this target and type
var list = target._listeners && target._listeners[type];
if (!list) return;
list = list.slice();
for(var i = 0, n = list.length; i < n; i++) {
if (event._immediatePropagationStopped) return;
var l = list[i];
if ((phase === Event.CAPTURING_PHASE && !l.capture) ||
(phase === Event.BUBBLING_PHASE && l.capture))
continue;
if (l.f) {
l.f.call(event.currentTarget, event);
}
else {
var fn = l.listener.handleEvent;
if (typeof fn !== 'function')
throw new TypeError('handleEvent property of event listener object is not a function.');
fn.call(l.listener, event);
}
}
}
if (!event._initialized || event._dispatching) utils.InvalidStateError();
event.isTrusted = trusted;
// Begin dispatching the event now
event._dispatching = true;
event.target = this;
// Build the list of targets for the capturing and bubbling phases
// XXX: we'll eventually have to add Window to this list.
var ancestors = [];
for(var n = this.parentNode; n; n = n.parentNode)
ancestors.push(n);
// Capturing phase
event.eventPhase = Event.CAPTURING_PHASE;
for(var i = ancestors.length-1; i >= 0; i--) {
invoke(ancestors[i], event);
if (event._propagationStopped) break;
}
// At target phase
if (!event._propagationStopped) {
event.eventPhase = Event.AT_TARGET;
invoke(this, event);
}
// Bubbling phase
if (event.bubbles && !event._propagationStopped) {
event.eventPhase = Event.BUBBLING_PHASE;
for(var ii = 0, nn = ancestors.length; ii < nn; ii++) {
invoke(ancestors[ii], event);
if (event._propagationStopped) break;
}
}
event._dispatching = false;
event.eventPhase = Event.AT_TARGET;
event.currentTarget = null;
// Deal with mouse events and figure out when
// a click has happened
if (trusted && !event.defaultPrevented && event instanceof MouseEvent) {
switch(event.type) {
case 'mousedown':
this._armed = {
x: event.clientX,
y: event.clientY,
t: event.timeStamp
};
break;
case 'mouseout':
case 'mouseover':
this._armed = null;
break;
case 'mouseup':
if (this._isClick(event)) this._doClick(event);
this._armed = null;
break;
}
}
return !event.defaultPrevented;
},
// Determine whether a click occurred
// XXX We don't support double clicks for now
_isClick: function(event) {
return (this._armed !== null &&
event.type === 'mouseup' &&
event.isTrusted &&
event.button === 0 &&
event.timeStamp - this._armed.t < 1000 &&
Math.abs(event.clientX - this._armed.x) < 10 &&
Math.abs(event.clientY - this._armed.Y) < 10);
},
// Clicks are handled like this:
// http://www.whatwg.org/specs/web-apps/current-work/multipage/elements.html#interactive-content-0
//
// Note that this method is similar to the HTMLElement.click() method
// The event argument must be the trusted mouseup event
_doClick: function(event) {
if (this._click_in_progress) return;
this._click_in_progress = true;
// Find the nearest enclosing element that is activatable
// An element is activatable if it has a
// _post_click_activation_steps hook
var activated = this;
while(activated && !activated._post_click_activation_steps)
activated = activated.parentNode;
if (activated && activated._pre_click_activation_steps) {
activated._pre_click_activation_steps();
}
var click = this.ownerDocument.createEvent('MouseEvent');
click.initMouseEvent('click', true, true,
this.ownerDocument.defaultView, 1,
event.screenX, event.screenY,
event.clientX, event.clientY,
event.ctrlKey, event.altKey,
event.shiftKey, event.metaKey,
event.button, null);
var result = this._dispatchEvent(click, true);
if (activated) {
if (result) {
// This is where hyperlinks get followed, for example.
if (activated._post_click_activation_steps)
activated._post_click_activation_steps(click);
}
else {
if (activated._cancelled_activation_steps)
activated._cancelled_activation_steps();
}
}
},
//
// An event handler is like an event listener, but it registered
// by setting an IDL or content attribute like onload or onclick.
// There can only be one of these at a time for any event type.
// This is an internal method for the attribute accessors and
// content attribute handlers that need to register events handlers.
// The type argument is the same as in addEventListener().
// The handler argument is the same as listeners in addEventListener:
// it can be a function or an object. Pass null to remove any existing
// handler. Handlers are always invoked before any listeners of
// the same type. They are not invoked during the capturing phase
// of event dispatch.
//
_setEventHandler: function _setEventHandler(type, handler) {
if (!this._handlers) this._handlers = Object.create(null);
this._handlers[type] = handler;
},
_getEventHandler: function _getEventHandler(type) {
return (this._handlers && this._handlers[type]) || null;
}
};