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eventcontract.js
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1664 lines (1490 loc) · 59.8 KB
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// Copyright 2005 Google Inc. All Rights Reserved.
/**
*
* @fileoverview Implements the local event handling contract. This
* allows DOM objects in a container that enters into this contract to
* define event handlers which are executed in a local context.
*
* One EventContract instance can manage the contract for multiple
* containers, which are added using the addContainer() method.
*
* Events can be registered using the addEvent() method.
*
* A Dispatcher is added using the dispatchTo() method. Until there is
* a dispatcher, events are queued. The idea is that the EventContract
* class is inlined in the HTML of the top level page and instantiated
* right after the start of <body>. The Dispatcher class is contained
* in the external deferred js, and instantiated and registered with
* EventContract when the external javascript in the page loads. The
* external javascript will also register the jsaction handlers, which
* then pick up the queued events at the time of registration.
*
* Since this class is meant to be inlined in the main page HTML, the
* size of the binary compiled from this file MUST be kept as small as
* possible and thus its dependencies to a minimum.
*/
goog.provide('jsaction.EventContract');
goog.provide('jsaction.EventContractContainer');
goog.require('goog.dom.TagName');
goog.require('jsaction.A11y');
goog.require('jsaction.Attribute');
goog.require('jsaction.Cache');
goog.require('jsaction.Char');
goog.require('jsaction.EventType');
goog.require('jsaction.Property');
goog.require('jsaction.createMouseEvent');
goog.require('jsaction.domGenerator');
goog.require('jsaction.event');
/**
* EventContract intercepts events in the bubbling phase at the
* boundary of a container element, and maps them to generic actions
* which are specified using the custom jsaction attribute in
* HTML. Behavior of the application is then specified in terms of
* handler for such actions, cf. jsaction.Dispatcher in dispatcher.js.
*
* This has several benefits: (1) No DOM event handlers need to be
* registered on the specific elements in the UI. (2) The set of
* events that the application has to handle can be specified in terms
* of the semantics of the application, rather than in terms of DOM
* events. (3) Invocation of handlers can be delayed and handlers can
* be delay loaded in a generic way.
*
* @constructor
*/
jsaction.EventContract = function() {
/**
* A list of functions. Each function will initialize a newly
* registered contract for one event. See addContainer().
*
* @type {!Array.<!jsaction.ContainerInitializerFunction>}
* @private
*/
this.installers_ = [];
/**
* The containers signed up for this event contract. See addContainer().
*
* @type {!Array.<!jsaction.EventContractContainer>}
* @private
*/
this.containers_ = [];
/**
* The list of containers that are children of an existing container. If
* STOP_PROPAGATION is false then we do not install event listeners on these
* (since that would cause the event to be triggered more than once). We do
* want to keep track of these containers such that we properly handle
* additions/removals.
* If STOP_PROPAGATION is true it is safe to add event listeners on all the
* containers.
* @type {!Array.<!jsaction.EventContractContainer>}
* @private
*/
this.nestedContainers_ = [];
/**
* The DOM events which this contract covers. Used to prevent double
* registration of event types. The value of the map is the
* internally created DOM event handler function that handles the
* DOM events. See addEvent().
*
* @type {!Object.<string, !jsaction.EventHandlerFunction>}
* @private
*/
this.events_ = {};
/**
* The dispatcher function. Events are passed to this function for
* handling once it was set using the dispatchTo() method. Usually
* the dispatcher is the bound dispatch() method of a
* jsaction.Dispatcher instance. This is done because the function
* is passed from another jsbinary, so passing the instance and
* invoking the method here would require to leave the method
* unobfuscated.
*
* @type {?function((!jsaction.EventInfo|!Array.<!jsaction.EventInfo>),
* boolean=):(!Event|void)}
* @private
*/
this.dispatcher_ = null;
/**
* The queue of events. Events are queued while there is no
* dispatcher set.
* @type {Array.<!jsaction.EventInfo>}
* @private
*/
this.queue_ = [];
if (jsaction.EventContract.CUSTOM_EVENT_SUPPORT) {
this.addEvent(jsaction.EventType.CUSTOM);
}
};
/**
* @define {boolean} Controls the use of event.path logic for the dom
* walking in createEventInfo_.
*/
jsaction.EventContract.USE_EVENT_PATH =
goog.define('jsaction.EventContract.USE_EVENT_PATH', false);
/**
* Whether the user agent is running on iOS.
* @type {boolean}
* @private
*/
jsaction.EventContract.isIos_ = typeof navigator != 'undefined' &&
/iPhone|iPad|iPod/.test(navigator.userAgent);
/**
* @define {boolean} Support for jsnamespace attribute. This flag can be
* overridden in a build rule to trim down the EventContract's binary size.
*/
jsaction.EventContract.JSNAMESPACE_SUPPORT =
goog.define('jsaction.EventContract.JSNAMESPACE_SUPPORT', true);
/**
* @define {boolean} Handles a11y click casting in the dispatcher rather than
* the event contract. When enabled, it will enable
* jsaction.EventContract.A11Y_CLICK_SUPPORT as well as both are required for
* this functionality.
*/
jsaction.EventContract.A11Y_SUPPORT_IN_DISPATCHER =
goog.define('jsaction.EventContract.A11Y_SUPPORT_IN_DISPATCHER', false);
/**
* @define {boolean} Support for accessible click actions. This flag can be
* overridden in a build rule.
* @private
*/
jsaction.EventContract.A11Y_CLICK_SUPPORT_FLAG_ENABLED_ =
goog.define('jsaction.EventContract.A11Y_CLICK_SUPPORT', false);
/**
* Forces A11y click support when the A11Y_SUPPORT_IN_DISPATCHER flag is true.
* @type {boolean}
*/
jsaction.EventContract.A11Y_CLICK_SUPPORT =
jsaction.EventContract.A11Y_CLICK_SUPPORT_FLAG_ENABLED_ ||
jsaction.EventContract.A11Y_SUPPORT_IN_DISPATCHER;
/**
* @define {boolean} Support for the non-bubbling mouseenter and mouseleave
* events. This flag can be overridden in a build rule.
*/
jsaction.EventContract.MOUSE_SPECIAL_SUPPORT =
goog.define('jsaction.EventContract.MOUSE_SPECIAL_SUPPORT', false);
/**
* @define {boolean} Simulate click events based on touch events for browsers
* that have a 300ms delay before they send the click event. This is
* currently EXPERIMENTAL.
*/
jsaction.EventContract.FAST_CLICK_SUPPORT =
goog.define('jsaction.EventContract.FAST_CLICK_SUPPORT', false);
/**
* @define {boolean} Call stopPropagation on handled events. When integrating
* with non-jsaction event handler based code, you will likely want to turn
* this flag off. While most event handlers will continue to work, jsaction
* binds focus and blur events in the capture phase and thus with
* stopPropagation, none of your non-jsaction-handlers will ever see it.
*/
jsaction.EventContract.STOP_PROPAGATION =
goog.define('jsaction.EventContract.STOP_PROPAGATION', true);
/**
* @define {boolean} Support for custom events, which are type
* jsaction.EventType.CUSTOM. These are native DOM events with an
* additional type field and an optional payload.
*/
jsaction.EventContract.CUSTOM_EVENT_SUPPORT =
goog.define('jsaction.EventContract.CUSTOM_EVENT_SUPPORT', false);
/**
* Specifies a click jsaction event type triggered by an Enter/Space DOM
* keypress.
* @private {string}
* @const
*/
jsaction.EventContract.CLICKKEY_ = 'clickkey';
/**
* Helper function to trim whitespace from the beginning and the end
* of the string. This deliberately doesn't use the closure equivalent
* to keep dependencies small.
*
* @param {string} str Input string.
* @return {string} Trimmed string.
* @private @const
*/
jsaction.EventContract.stringTrim_ = String.prototype.trim ? function(str) {
return str.trim();
} : function(str) {
const trimmedLeft = str.replace(/^\s+/, '');
return trimmedLeft.replace(/\s+$/, '');
};
/**
* This regular expression matches a semicolon.
* @type {RegExp}
* @private
* @const
*/
jsaction.EventContract.REGEXP_SEMICOLON_ = /\s*;\s*/;
/**
* The default event type.
* @type {string}
* @private
*/
jsaction.EventContract.defaultEventType_ = jsaction.EventType.CLICK;
/**
* Information about an element that received a touchstart event
* that we might want to translate into a click event once a touchend
* event arrives.
*
* - node is the target element of the event.
* - x and y are clientX and clientY of the event, respectively.
*
* The fields of this Object are unquoted.
*
* This object is reset when either touchend arrives within a short period of
* time or when "fast click" is canceled due to touchmove or expiration. See
* "resetFastClickNode_" method for more detail.
*
* @private {?{node: !Element, x: number, y: number}}
*/
jsaction.EventContract.fastClickNode_;
/**
* The last emitted touchend event. It's used to ignore subsequent mouse
* events when requested by "_preventMouseEvents".
* @private {?Event}
*/
jsaction.EventContract.preventingMouseEvents_ = null;
/**
* A timer that we schedule after a touchstart. If the timer fires before the
* touchend event, the press is considered a long-press that does not get
* translated into a click.
* @private {number}
*/
jsaction.EventContract.fastClickTimeout_;
/**
* Gets the default event type.
* @return {string} The default event type.
*/
jsaction.EventContract.getDefaultEventType = function() {
return jsaction.EventContract.defaultEventType_;
};
/**
* Sets a new default event type.
* @param {string} eventType The new default event type.
*/
jsaction.EventContract.setDefaultEventType = function(eventType) {
jsaction.EventContract.defaultEventType_ = eventType;
};
/**
* Returns a function that handles events on a container and invokes a local
* event handler (bound using the actions map) on the source node or any of
* its ancestors up to the container to which the returned event handler
* belongs. The local event handler is passed an ActionFlow which allows
* access to the node, event, and values defined on the node. If there are no
* jsaction handlers bound that can handle this event, the flow representing
* the event is stored in a queue for replaying at a later time.
*
* @param {!jsaction.EventContract} eventContract The EventContract
* instance to create this handler for.
* @param {string} eventType The type of the event - e.g. 'click'.
* Note that event.type can differ from eventType. In some browsers (e.g.
* Firefox) the event handling code registers handlers for 'focusin' and
* 'focusout' to handle 'focus' and 'blur' respectively. In those cases,
* event.type might be 'focus', but eventType will be 'focusin'.
* @return {jsaction.EventHandlerFunction} The DOM event handler to
* use for the given event type on all containers.
* @private
*/
jsaction.EventContract.eventHandler_ = function(eventContract, eventType) {
/**
* See description above.
* @param {!Event} e Event.
* @param {boolean=} allowRehandling Used in the case of a11y click casting to
* prevent us from trying to rehandle in an infinite loop.
* @this {!Element}
*/
const handler = function handleEvent(e, allowRehandling = true) {
const container = this;
// Store eventType's value in a local variable so that multiple calls do not
// modify the shared eventType variable.
let eventTypeForDispatch = eventType;
if (jsaction.EventContract.CUSTOM_EVENT_SUPPORT &&
eventTypeForDispatch == jsaction.EventType.CUSTOM) {
const detail = e['detail'];
// For custom events, use a secondary dispatch based on the internal
// custom type of the event.
if (!detail || !detail['_type']) {
// This should never happen.
return;
}
eventTypeForDispatch = detail['_type'];
}
const eventInfo = jsaction.EventContract.createEventInfo_(
eventTypeForDispatch, e, container);
if (eventContract.dispatcher_ &&
!eventInfo['event'][jsaction.A11y.SKIP_GLOBAL_DISPATCH]) {
const globalEventInfo = jsaction.EventContract.createEventInfoInternal_(
eventInfo['eventType'], eventInfo['event'],
eventInfo['targetElement'], eventInfo['action'],
eventInfo['actionElement'], eventInfo['timeStamp']);
// In some cases, createEventInfo_() will rewrite click events to
// clickonly. Revert back to a regular click, otherwise we won't be able
// to execute global event handlers registered on click events.
if (globalEventInfo['eventType'] == jsaction.EventType.CLICKONLY) {
globalEventInfo['eventType'] = jsaction.EventType.CLICK;
}
eventContract.dispatcher_(
globalEventInfo, /* dispatch global event */ true);
}
if (jsaction.EventContract.canSkipDispatch_(eventInfo)) {
return;
}
let stopPropagationAfterDispatch = false;
if (jsaction.EventContract.STOP_PROPAGATION &&
eventInfo['eventType'] !== jsaction.A11y.MAYBE_CLICK_EVENT_TYPE) {
if (jsaction.event.isGecko &&
(eventInfo['targetElement'].tagName == goog.dom.TagName.INPUT ||
eventInfo['targetElement'].tagName == goog.dom.TagName.TEXTAREA) &&
(eventInfo['eventType'] == jsaction.EventType.FOCUS)) {
// Do nothing since stopping propagation a focus event on an input
// element in Firefox makes the text cursor disappear:
// https://bugzilla.mozilla.org/show_bug.cgi?id=509684
} else {
// Since we found a jsaction, prevent other handlers from seeing
// this event.
jsaction.event.stopPropagation(e);
}
} else if (
jsaction.EventContract.STOP_PROPAGATION &&
eventInfo['eventType'] === jsaction.A11y.MAYBE_CLICK_EVENT_TYPE) {
// We first need to let the dispatcher determine whether we can treat this
// event as a click event.
stopPropagationAfterDispatch = true;
}
if (eventContract.dispatcher_) {
if (jsaction.EventContract.shouldPreventDefaultBeforeDispatching(
eventInfo)) {
jsaction.event.preventDefault(e);
}
const eventToRetry = eventContract.dispatcher_(eventInfo);
if (eventToRetry && allowRehandling) {
// The dispatcher only returns an event for MAYBE_CLICK_EVENT_TYPE
// events that can't be casted to a click. We run it through the
// handler again to find keydown actions for it.
handleEvent.call(this, eventToRetry, /* allowRehandling =*/ false);
return;
}
if (stopPropagationAfterDispatch) {
jsaction.event.stopPropagation(eventInfo['event']);
}
} else {
jsaction.EventContract.queueEvent(eventContract, eventInfo, e);
}
jsaction.EventContract.afterEventHandler_(eventInfo);
};
return handler;
};
/**
* Returns true if the default action of this event should be prevented before
* this event is dispatched.
*
* This is primarily for internal use.
*
* @param {!jsaction.EventInfo} eventInfo The event info object.
* @return {boolean}
*/
jsaction.EventContract.shouldPreventDefaultBeforeDispatching = function(
eventInfo) {
// Prevent browser from following <a> node links if a jsaction is present
// and we are dispatching the action now. Note that the targetElement may be a
// child of an anchor that has a jsaction attached. For that reason, we need
// to check the actionElement rather than the targetElement.
return eventInfo['actionElement'] &&
eventInfo['actionElement'].tagName == goog.dom.TagName.A &&
(eventInfo['eventType'] == jsaction.EventType.CLICK ||
eventInfo['eventType'] == jsaction.EventType.CLICKMOD);
};
/**
* Queue an event to be replayed. This is called when an event is handled but no
* dispatcher is registered yet to handle it.
*
* This is primarily for internal use.
*
* @param {!jsaction.EventContract} eventContract The EventContract
* instance to queue the event on.
* @param {!jsaction.EventInfo} eventInfo The event info object.
* @param {!Event} e Event.
*/
jsaction.EventContract.queueEvent = function(eventContract, eventInfo, e) {
const copiedEvent = jsaction.event.maybeCopyEvent(e);
// The event is queued since there is no dispatcher registered
// yet. Potentially make a copy of the event in order to extend its
// life. The copy will later be used when attempting to replay.
eventInfo['event'] = copiedEvent;
eventContract.queue_.push(eventInfo);
};
/**
* Post-processes event. Called after event has been sent to the handler.
* @param {!jsaction.EventInfo} eventInfo
* @private
*/
jsaction.EventContract.afterEventHandler_ = function(eventInfo) {
// Setup sweeper if mouse events have been canceled.
if (eventInfo.event.type == jsaction.EventType.TOUCHEND &&
jsaction.event.isMouseEventsPrevented(eventInfo.event)) {
jsaction.EventContract.preventingMouseEvents_ = /** @type {!Event} */ (
jsaction.event.recreateTouchEventAsClick(eventInfo.event));
}
};
/**
* Searches for a jsaction that the DOM event maps to and creates an
* object containing event information used for dispatching by
* jsaction.Dispatcher. The dispatch information returned consists of
* the event type, target element, action and the Event instance
* supplied by the DOM. The jsaction for the DOM event is the first
* jsaction attribute above the target Node of the event, and below
* the container Node, that specifies a jsaction for the event
* type. If no such jsaction is found, the actionElement properties is null.
*
* @param {string} eventType The type of the event, e.g. 'click', as
* specified by event contract. This may differ from the DOM event
* type, because event contract may use more generic event types.
* @param {!Event} e The Event instance received by the container from
* the DOM.
* @param {!Node} container The container which limits the search for
* jsactions which can handle the event.
* @return {jsaction.EventInfo} The event info object. If its actionElement
* property is null, no jsaction was found above the target Node of the
* event.
* @private
*/
jsaction.EventContract.createEventInfo_ = function(eventType, e, container) {
// We distinguish modified and plain clicks in order to support the
// default browser behavior of modified clicks on links; usually to
// open the URL of the link in new tab or new window on ctrl/cmd
// click. A DOM 'click' event is mapped to the jsaction 'click'
// event iff there is no modifier present on the event. If there is
// a modifier, it's mapped to 'clickmod' instead.
//
// It's allowed to omit the event in the jsaction attribute. In that
// case, 'click' is assumed. Thus the following two are equivalent:
//
// <a href="someurl" jsaction="gna.fu">
// <a href="someurl" jsaction="click:gna.fu">
//
// For unmodified clicks, EventContract invokes the jsaction
// 'gna.fu'. For modified clicks, EventContract won't find a
// suitable action and leave the event to be handled by the
// browser.
//
// In order to also invoke a jsaction handler for a modifier click,
// 'clickmod' needs to be used:
//
// <a href="someurl" jsaction="clickmod:gna.fu">
//
// EventContract invokes the jsaction 'gna.fu' for modified
// clicks. Unmodified clicks are left to the browser.
//
// In order to set up the event contract to handle both clickonly and
// clickmod, only addEvent(jsaction.EventType.CLICK) is necessary.
//
// In order to set up the event contract to handle click,
// addEvent() is necessary for CLICK, KEYDOWN, and KEYPRESS event types. If
// the jsaction.EventContract.A11Y_CLICK_SUPPORT flag is turned on, addEvent()
// will set up the appropriate key event handler automatically.
if (eventType == jsaction.EventType.CLICK &&
jsaction.event.isModifiedClickEvent(e)) {
eventType = jsaction.EventType.CLICKMOD;
} else if (
jsaction.EventContract.A11Y_SUPPORT_IN_DISPATCHER &&
jsaction.EventContract.A11Y_CLICK_SUPPORT &&
eventType == jsaction.EventType.KEYDOWN &&
!e[jsaction.A11y.SKIP_A11Y_CHECK]) {
// We use a string literal as this value needs to be referenced in the
// dispatcher's binary.
eventType = jsaction.A11y.MAYBE_CLICK_EVENT_TYPE;
} else if (
!jsaction.EventContract.A11Y_SUPPORT_IN_DISPATCHER &&
jsaction.EventContract.A11Y_CLICK_SUPPORT &&
jsaction.event.isActionKeyEvent(e)) {
eventType = jsaction.EventContract.CLICKKEY_;
}
const target = /** @type {!Element} */ (e.srcElement || e.target);
let eventInfo = jsaction.EventContract.createEventInfoInternal_(
eventType, e, target, '', null);
// NOTE(user): In order to avoid complicating the code that calculates the
// event's path, we need a common interface to iterating over event.path or
// walking the DOM. We use the generator pattern here, as generating the
// path array ahead of time for DOM walks will result in degraded
// performance.
/** @type {jsaction.ActionInfo} */
let actionInfo;
// NOTE(user): This is a work around some issues with custom dispatchers.
let element;
if (jsaction.EventContract.USE_EVENT_PATH) {
const generator = jsaction.domGenerator.getGenerator(
e, target, /** @type {!Element} */ (container));
for (let node; node = generator.next();) {
element = node;
actionInfo =
jsaction.EventContract.getAction_(element, eventType, e, container);
eventInfo = jsaction.EventContract.createEventInfoInternal_(
actionInfo.eventType, actionInfo.event || e, target,
actionInfo.action || '', element, eventInfo['timeStamp']);
// TODO(user): If we can get rid of the break on actionInfo.ignore
// these loops can collapse down to one and the contents can live in
// a function.
// Stop walking the DOM prematurely if we will ignore this event. This is
// used solely for fastbutton's implementation.
if (actionInfo.ignore ||
// An event is handled by at most one jsaction. Thus we stop at
// the first matching jsaction specified in a jsaction attribute
// up the ancestor chain of the event target node.
actionInfo.action) {
break;
}
}
} else {
for (let node = target; node && node != container;
// Walk to the parent node, unless the node has a different owner in
// which case we walk to the owner.
node = node[jsaction.Property.OWNER] || node.parentNode) {
element = node;
actionInfo =
jsaction.EventContract.getAction_(element, eventType, e, container);
// Stop walking the DOM prematurely if we will ignore this event. This is
// used solely for fastbutton's implementation.
if (actionInfo.ignore ||
// An event is handled by at most one jsaction. Thus we stop at
// the first matching jsaction specified in a jsaction attribute
// up the ancestor chain of the event target node.
actionInfo.action) {
break;
}
}
if (actionInfo) {
eventInfo = jsaction.EventContract.createEventInfoInternal_(
actionInfo.eventType, actionInfo.event || e, target,
actionInfo.action || '', element, eventInfo['timeStamp']);
}
}
// A touchend is "enhanced" to support mouse-events canceling.
if (eventInfo && eventInfo['eventType'] == jsaction.EventType.TOUCHEND) {
jsaction.event.addPreventMouseEventsSupport(eventInfo['event']);
}
if (actionInfo && actionInfo.action) {
// Prevent scrolling if the Space key was pressed or prevent the browser's
// default action for native HTML controls.
if (!jsaction.EventContract.A11Y_SUPPORT_IN_DISPATCHER &&
jsaction.EventContract.A11Y_CLICK_SUPPORT &&
eventType == jsaction.EventContract.CLICKKEY_ &&
(jsaction.event.isSpaceKeyEvent(e) ||
jsaction.event.shouldCallPreventDefaultOnNativeHtmlControl(e))) {
jsaction.event.preventDefault(e);
}
// We attempt to handle the mouseenter/mouseleave events here by
// detecting whether the mouseover/mouseout events correspond to
// entering/leaving an element.
if (jsaction.EventContract.MOUSE_SPECIAL_SUPPORT &&
(eventType == jsaction.EventType.MOUSEENTER ||
eventType == jsaction.EventType.MOUSELEAVE)) {
// We attempt to handle the mouseenter/mouseleave events here by
// detecting whether the mouseover/mouseout events correspond to
// entering/leaving an element.
if (jsaction.event.isMouseSpecialEvent(e, eventType, element)) {
// If both mouseover/mouseout and mouseenter/mouseleave events are
// enabled, two separate handlers for mouseover/mouseout are
// registered. Both handlers will see the same event instance
// so we create a copy to avoid interfering with the dispatching of
// the mouseover/mouseout event.
const copiedEvent = jsaction.event.createMouseSpecialEvent(
e, /** @type {!Element} */ (element));
eventInfo['event'] = /** @type {!Event} */ (copiedEvent);
// Since the mouseenter/mouseleave events do not bubble, the target
// of the event is technically the node on which the jsaction is
// specified (the actionElement).
eventInfo['targetElement'] = element;
} else {
eventInfo['action'] = '';
eventInfo['actionElement'] = null;
}
}
return eventInfo;
}
// Reset action-related properties of the current eventInfo, to ensure we
// won't dispatch a non-existing action.
eventInfo['action'] = '';
eventInfo['actionElement'] = null;
return eventInfo;
};
/**
* @param {string} eventType
* @param {!Event} e
* @param {!Element} targetElement
* @param {string} action
* @param {Element} actionElement
* @param {number=} opt_timeStamp
* @return {jsaction.EventInfo}
* @private
*/
jsaction.EventContract.createEventInfoInternal_ = function(
eventType, e, targetElement, action, actionElement, opt_timeStamp) {
// Event#timeStamp is broken on Firefox for synthetic events. See
// https://bugzilla.mozilla.org/show_bug.cgi?id=238041 for details. Since
// Firefox marks Event#timeStamp as read-only, the only workaround is to
// expose a timestamp directly in eventInfo, to be consistent across all
// browsers.
return /** @type {jsaction.EventInfo} */ ({
'eventType': eventType,
'event': e,
'targetElement': targetElement,
'action': action,
'actionElement': actionElement,
'timeStamp': opt_timeStamp || goog.now()
});
};
/**
* Determines if we can skip triggering the dispatcher based on the eventType
* and action found.
*
* @param {!jsaction.EventInfo} eventInfo
* @return {boolean}
* @private
*/
jsaction.EventContract.canSkipDispatch_ = function(eventInfo) {
// Return early if no action element found while walking up the DOM tree.
if (!jsaction.EventContract.A11Y_SUPPORT_IN_DISPATCHER &&
!eventInfo['actionElement']) {
return true;
}
// Return early in A11Y_SUPPORT_IN_DISPATCHER mode only if the eventType is
// not MAYBE_CLICK_EVENT_TYPE, because if it is, we want the dispatcher to
// check the key event and retrigger the event if necessary.
if (jsaction.EventContract.A11Y_SUPPORT_IN_DISPATCHER &&
!eventInfo['actionElement'] &&
eventInfo['eventType'] != jsaction.A11y.MAYBE_CLICK_EVENT_TYPE) {
return true;
}
return false;
};
/**
* Accesses the event handler attribute value of a DOM node. It guards
* against weird situations (described in the body) that occur in
* connection with nodes that are removed from their document.
* @param {!Element} node The DOM node.
* @param {string} attribute The name of the attribute to access.
* @return {?string} The attribute value if it was found, null
* otherwise.
* @private
*/
jsaction.EventContract.getAttr_ = function(node, attribute) {
let value = null;
// NOTE(user): Nodes in IE do not always have a getAttribute
// method defined. This is the case where sourceElement has in
// fact been removed from the DOM before eventContract begins
// handling - where a parentNode does not have getAttribute
// defined.
// NOTE(ruilopes): We must use the 'in' operator instead of the regular dot
// notation, since the latter fails in IE8 if the getAttribute method is not
// defined. See b/7139109.
if ('getAttribute' in node) {
value = node.getAttribute(attribute);
}
return value;
};
/**
* Since maps from event to action are immutable we can use a single map
* to represent the empty map.
* @private @const {!Object.<string, string>}
*/
jsaction.EventContract.EMPTY_ACTION_MAP_ = {};
/**
* Parses and caches an element's jsaction element into a map.
*
* This is primarily for internal use.
*
* @param {!Element} node The DOM node to retrieve the jsaction map from.
* @param {!Node} container The node which limits the namespace lookup
* for a jsaction name. The container node itself will not be
* searched.
* @return {!Object.<string, string>} Map from event to qualified name
* of the jsaction bound to it.
*/
jsaction.EventContract.parseActions = function(node, container) {
let actionMap = jsaction.Cache.get(node);
if (!actionMap) {
const attvalue =
jsaction.EventContract.getAttr_(node, jsaction.Attribute.JSACTION);
if (!attvalue) {
actionMap = jsaction.EventContract.EMPTY_ACTION_MAP_;
jsaction.Cache.set(node, actionMap);
} else {
actionMap = jsaction.Cache.getParsed(attvalue);
if (!actionMap) {
actionMap = {};
const values = attvalue.split(jsaction.EventContract.REGEXP_SEMICOLON_);
const I = values ? values.length : 0;
for (let idx = 0; idx < I; idx++) {
const value = values[idx];
if (!value) {
continue;
}
const colon = value.indexOf(jsaction.Char.EVENT_ACTION_SEPARATOR);
const hasColon = colon != -1;
const type = hasColon ?
jsaction.EventContract.stringTrim_(value.substr(0, colon)) :
jsaction.EventContract.defaultEventType_;
const action = hasColon ?
jsaction.EventContract.stringTrim_(value.substr(colon + 1)) :
value;
actionMap[type] = action;
}
jsaction.Cache.setParsed(attvalue, actionMap);
}
// If namespace support is active we need to augment the (potentially
// cached) jsaction mapping with the namespace.
if (jsaction.EventContract.JSNAMESPACE_SUPPORT) {
const noNs = actionMap;
actionMap = {};
for (let type in noNs) {
actionMap[type] = jsaction.EventContract.getQualifiedName_(
noNs[type], node, container);
}
}
jsaction.Cache.set(node, actionMap);
}
}
return actionMap;
};
/**
* Accesses the jsaction map on a node and retrieves the name of the
* action the given event is mapped to, if any. It parses the
* attribute value and stores it in a property on the node for
* subsequent retrieval without re-parsing and re-accessing the
* attribute. In order to fully qualify jsaction names using a
* namespace, the DOM is searched starting at the current node and
* going through ancestor nodes until a jsnamespace attribute is
* found.
*
* @param {!Element} node The DOM node to retrieve the jsaction map
* from.
* @param {string} eventType The type of the event for which to
* retrieve the action.
* @param {!Event} event The current browser event.
* @param {!Node} container The node which limits the namespace lookup
* for a jsaction name. The container node itself will not be
* searched.
* @return {!jsaction.ActionInfo} The action info.
* @private
*/
jsaction.EventContract.getAction_ = function(
node, eventType, event, container) {
const actionMap = jsaction.EventContract.parseActions(node, container);
let originalEventType;
if (jsaction.EventContract.A11Y_CLICK_SUPPORT) {
if (eventType == jsaction.A11y.MAYBE_CLICK_EVENT_TYPE &&
actionMap[jsaction.EventType.CLICK]) {
// We'll take the first CLICK action we find and have the dispatcher check
// if the keydown event can be used as a CLICK. If not, the dispatcher
// will retrigger the event so that we can find a keydown event instead.
originalEventType = eventType;
eventType = jsaction.EventType.CLICK;
} else if (eventType == jsaction.EventContract.CLICKKEY_) {
// A 'click' triggered by a DOM keypress should be mapped to the 'click'
// jsaction.
eventType = jsaction.EventType.CLICK;
} else if (
eventType == jsaction.EventType.CLICK &&
!actionMap[jsaction.EventType.CLICK]) {
// A 'click' triggered by a DOM click should be mapped to the 'click'
// jsaction, if available, or else fallback to the 'clickonly' jsaction.
// If 'click' and 'clickonly' jsactions are used together, 'click' will
// prevail.
eventType = jsaction.EventType.CLICKONLY;
}
}
let overrideEvent = null;
if (jsaction.EventContract.FAST_CLICK_SUPPORT &&
// Don't want fast click behavior? Just bind clickonly instead.
actionMap[jsaction.EventType.CLICK]) {
const fastEvent =
jsaction.EventContract.getFastClickEvent_(node, event, actionMap);
if (!fastEvent) {
// Null means to stop looking for further events, as the logic event
// has already been handled or the event started a sequence that may
// eventually lead to a logic click event.
return {eventType: eventType, action: '', event: null, ignore: true};
} else if (fastEvent != event) {
overrideEvent = fastEvent;
eventType = fastEvent.type;
}
}
// An empty action indicates that no jsaction attribute was found in the given
// DOM node.
const actionName = actionMap[eventType] || '';
// When we get MAYBE_CLICK_EVENT_TYPE as an eventType, we want to retrieve the
// action corresponding to CLICK, but still keep the eventType as
// MAYBE_CLICK_EVENT_TYPE. The dispatcher uses this event type to determine if
// it should get the handler for the action.
return {
eventType: originalEventType ? originalEventType : eventType,
action: actionName,
event: overrideEvent,
ignore: false
};
};
/**
* Returns the qualified jsaction name, i.e. the name of the jsaction
* including the namespace part before the dot. If the given jsaction
* name doesn't already contain the namespace, the function iterates
* over ancestor nodes until a jsnamespace attribute is found, and
* uses the value of that attribute as the namespace.
*
* @param {string} name The jsaction name to resolve the namespace of.
* @param {Element} start The node from which to start searching for a
* jsnamespace attribute.
* @param {Node} container The node which limits the search for a
* jsnamespace attribute. This node will be searched.
* @return {string} The qualified name of the jsaction. If no
* namespace is found, returns the unqualified name in case it
* exists in the global namespace.
* @private
*/
jsaction.EventContract.getQualifiedName_ = function(name, start, container) {
if (jsaction.EventContract.JSNAMESPACE_SUPPORT) {
if (jsaction.EventContract.isQualifiedName_(name)) {
return name;
}
for (let node = start; node; node = node.parentNode) {
const ns = jsaction.EventContract.getNamespace_(
/** @type {!Element} */ (node));
if (ns) {
return ns + jsaction.Char.NAMESPACE_ACTION_SEPARATOR + name;
}
// If this node is the container, stop.
if (node == container) {
break;
}
}
}
return name;
};
/**
* Converts a sequence of touchstart and touchend events into a click event
* and ignores a subsequent click event (within 400ms).
*
* This method returns the original or a synthesized event instance, or null if
* the event should be ignored. The original event indicates that the original
* event should proceed as planned. If the event should be ignored (e.g. to
* issue a new event later), the returned value is null. However, if the
* "fast click" event is determined, a newly synthesized event instance is
* returned. The "click" event has to be synthesized to imitate an actual
* "click" event based on "touchend". This includes filling in type, target,
* clientX/Y, etc, which are expected from a "click" event. The original Event
* instance cannot simply be modified, because the DOM Event Spec defines Event
* properties to be immutable, and some browsers (specifically Safari in iOS/8)
* enforce this.
*
* @param {!Element} node The current node with a jsaction annotation.
* @param {!Event} event The current browser event.
* @param {!Object.<string, string>} actionMap
* @return {Event}
* @private
*/
jsaction.EventContract.getFastClickEvent_ = function(node, event, actionMap) {
if (event.type == jsaction.EventType.CLICK) {
return event;
}
if (event.targetTouches && event.targetTouches.length > 1) {
// Click emulation does not make sense for multi touch.
return event;
}
const fastClickNode = jsaction.EventContract.fastClickNode_;
const target = event.target;
if (target) {
// Don't do anything special for clicks on elements with elaborate built in
// click and focus behavior.
if (jsaction.EventContract.isInput_(target)) {
return event;
}
}
const touch = jsaction.event.getTouchData(event);