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wallet-core/node_modules/react-dom/lib/ResponderEventPlugin.js

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node_modules
2017-05-03 15:35:00 +02:00
/**
* Copyright 2013-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
*/
'use strict';
var EventPluginUtils = require('./EventPluginUtils');
var EventPropagators = require('./EventPropagators');
var ResponderSyntheticEvent = require('./ResponderSyntheticEvent');
var ResponderTouchHistoryStore = require('./ResponderTouchHistoryStore');
var accumulate = require('./accumulate');
var isStartish = EventPluginUtils.isStartish;
var isMoveish = EventPluginUtils.isMoveish;
var isEndish = EventPluginUtils.isEndish;
var executeDirectDispatch = EventPluginUtils.executeDirectDispatch;
var hasDispatches = EventPluginUtils.hasDispatches;
var executeDispatchesInOrderStopAtTrue = EventPluginUtils.executeDispatchesInOrderStopAtTrue;
/**
* Instance of element that should respond to touch/move types of interactions,
* as indicated explicitly by relevant callbacks.
*/
var responderInst = null;
/**
* Count of current touches. A textInput should become responder iff the
* selection changes while there is a touch on the screen.
*/
var trackedTouchCount = 0;
/**
* Last reported number of active touches.
*/
var previousActiveTouches = 0;
var changeResponder = function (nextResponderInst, blockHostResponder) {
var oldResponderInst = responderInst;
responderInst = nextResponderInst;
if (ResponderEventPlugin.GlobalResponderHandler !== null) {
ResponderEventPlugin.GlobalResponderHandler.onChange(oldResponderInst, nextResponderInst, blockHostResponder);
}
};
var eventTypes = {
/**
* On a `touchStart`/`mouseDown`, is it desired that this element become the
* responder?
*/
startShouldSetResponder: {
phasedRegistrationNames: {
bubbled: 'onStartShouldSetResponder',
captured: 'onStartShouldSetResponderCapture'
}
},
/**
* On a `scroll`, is it desired that this element become the responder? This
* is usually not needed, but should be used to retroactively infer that a
* `touchStart` had occurred during momentum scroll. During a momentum scroll,
* a touch start will be immediately followed by a scroll event if the view is
* currently scrolling.
*
* TODO: This shouldn't bubble.
*/
scrollShouldSetResponder: {
phasedRegistrationNames: {
bubbled: 'onScrollShouldSetResponder',
captured: 'onScrollShouldSetResponderCapture'
}
},
/**
* On text selection change, should this element become the responder? This
* is needed for text inputs or other views with native selection, so the
* JS view can claim the responder.
*
* TODO: This shouldn't bubble.
*/
selectionChangeShouldSetResponder: {
phasedRegistrationNames: {
bubbled: 'onSelectionChangeShouldSetResponder',
captured: 'onSelectionChangeShouldSetResponderCapture'
}
},
/**
* On a `touchMove`/`mouseMove`, is it desired that this element become the
* responder?
*/
moveShouldSetResponder: {
phasedRegistrationNames: {
bubbled: 'onMoveShouldSetResponder',
captured: 'onMoveShouldSetResponderCapture'
}
},
/**
* Direct responder events dispatched directly to responder. Do not bubble.
*/
responderStart: { registrationName: 'onResponderStart' },
responderMove: { registrationName: 'onResponderMove' },
responderEnd: { registrationName: 'onResponderEnd' },
responderRelease: { registrationName: 'onResponderRelease' },
responderTerminationRequest: {
registrationName: 'onResponderTerminationRequest'
},
responderGrant: { registrationName: 'onResponderGrant' },
responderReject: { registrationName: 'onResponderReject' },
responderTerminate: { registrationName: 'onResponderTerminate' }
};
/**
*
* Responder System:
* ----------------
*
* - A global, solitary "interaction lock" on a view.
* - If a node becomes the responder, it should convey visual feedback
* immediately to indicate so, either by highlighting or moving accordingly.
* - To be the responder means, that touches are exclusively important to that
* responder view, and no other view.
* - While touches are still occurring, the responder lock can be transferred to
* a new view, but only to increasingly "higher" views (meaning ancestors of
* the current responder).
*
* Responder being granted:
* ------------------------
*
* - Touch starts, moves, and scrolls can cause an ID to become the responder.
* - We capture/bubble `startShouldSetResponder`/`moveShouldSetResponder` to
* the "appropriate place".
* - If nothing is currently the responder, the "appropriate place" is the
* initiating event's `targetID`.
* - If something *is* already the responder, the "appropriate place" is the
* first common ancestor of the event target and the current `responderInst`.
* - Some negotiation happens: See the timing diagram below.
* - Scrolled views automatically become responder. The reasoning is that a
* platform scroll view that isn't built on top of the responder system has
* began scrolling, and the active responder must now be notified that the
* interaction is no longer locked to it - the system has taken over.
*
* - Responder being released:
* As soon as no more touches that *started* inside of descendants of the
* *current* responderInst, an `onResponderRelease` event is dispatched to the
* current responder, and the responder lock is released.
*
* TODO:
* - on "end", a callback hook for `onResponderEndShouldRemainResponder` that
* determines if the responder lock should remain.
* - If a view shouldn't "remain" the responder, any active touches should by
* default be considered "dead" and do not influence future negotiations or
* bubble paths. It should be as if those touches do not exist.
* -- For multitouch: Usually a translate-z will choose to "remain" responder
* after one out of many touches ended. For translate-y, usually the view
* doesn't wish to "remain" responder after one of many touches end.
* - Consider building this on top of a `stopPropagation` model similar to
* `W3C` events.
* - Ensure that `onResponderTerminate` is called on touch cancels, whether or
* not `onResponderTerminationRequest` returns `true` or `false`.
*
*/
/* Negotiation Performed
+-----------------------+
/ \
Process low level events to + Current Responder + wantsResponderID
determine who to perform negot-| (if any exists at all) |
iation/transition | Otherwise just pass through|
-------------------------------+----------------------------+------------------+
Bubble to find first ID | |
to return true:wantsResponderID| |
| |
+-------------+ | |
| onTouchStart| | |
+------+------+ none | |
| return| |
+-----------v-------------+true| +------------------------+ |
|onStartShouldSetResponder|----->|onResponderStart (cur) |<-----------+
+-----------+-------------+ | +------------------------+ | |
| | | +--------+-------+
| returned true for| false:REJECT +-------->|onResponderReject
| wantsResponderID | | | +----------------+
| (now attempt | +------------------+-----+ |
| handoff) | | onResponder | |
+------------------->| TerminationRequest| |
| +------------------+-----+ |
| | | +----------------+
| true:GRANT +-------->|onResponderGrant|
| | +--------+-------+
| +------------------------+ | |
| | onResponderTerminate |<-----------+
| +------------------+-----+ |
| | | +----------------+
| +-------->|onResponderStart|
| | +----------------+
Bubble to find first ID | |
to return true:wantsResponderID| |
| |
+-------------+ | |
| onTouchMove | | |
+------+------+ none | |
| return| |
+-----------v-------------+true| +------------------------+ |
|onMoveShouldSetResponder |----->|onResponderMove (cur) |<-----------+
+-----------+-------------+ | +------------------------+ | |
| | | +--------+-------+
| returned true for| false:REJECT +-------->|onResponderRejec|
| wantsResponderID | | | +----------------+
| (now attempt | +------------------+-----+ |
| handoff) | | onResponder | |
+------------------->| TerminationRequest| |
| +------------------+-----+ |
| | | +----------------+
| true:GRANT +-------->|onResponderGrant|
| | +--------+-------+
| +------------------------+ | |
| | onResponderTerminate |<-----------+
| +------------------+-----+ |
| | | +----------------+
| +-------->|onResponderMove |
| | +----------------+
| |
| |
Some active touch started| |
inside current responder | +------------------------+ |
+------------------------->| onResponderEnd | |
| | +------------------------+ |
+---+---------+ | |
| onTouchEnd | | |
+---+---------+ | |
| | +------------------------+ |
+------------------------->| onResponderEnd | |
No active touches started| +-----------+------------+ |
inside current responder | | |
| v |
| +------------------------+ |
| | onResponderRelease | |
| +------------------------+ |
| |
+ + */
/**
* A note about event ordering in the `EventPluginHub`.
*
* Suppose plugins are injected in the following order:
*
* `[R, S, C]`
*
* To help illustrate the example, assume `S` is `SimpleEventPlugin` (for
* `onClick` etc) and `R` is `ResponderEventPlugin`.
*
* "Deferred-Dispatched Events":
*
* - The current event plugin system will traverse the list of injected plugins,
* in order, and extract events by collecting the plugin's return value of
* `extractEvents()`.
* - These events that are returned from `extractEvents` are "deferred
* dispatched events".
* - When returned from `extractEvents`, deferred-dispatched events contain an
* "accumulation" of deferred dispatches.
* - These deferred dispatches are accumulated/collected before they are
* returned, but processed at a later time by the `EventPluginHub` (hence the
* name deferred).
*
* In the process of returning their deferred-dispatched events, event plugins
* themselves can dispatch events on-demand without returning them from
* `extractEvents`. Plugins might want to do this, so that they can use event
* dispatching as a tool that helps them decide which events should be extracted
* in the first place.
*
* "On-Demand-Dispatched Events":
*
* - On-demand-dispatched events are not returned from `extractEvents`.
* - On-demand-dispatched events are dispatched during the process of returning
* the deferred-dispatched events.
* - They should not have side effects.
* - They should be avoided, and/or eventually be replaced with another
* abstraction that allows event plugins to perform multiple "rounds" of event
* extraction.
*
* Therefore, the sequence of event dispatches becomes:
*
* - `R`s on-demand events (if any) (dispatched by `R` on-demand)
* - `S`s on-demand events (if any) (dispatched by `S` on-demand)
* - `C`s on-demand events (if any) (dispatched by `C` on-demand)
* - `R`s extracted events (if any) (dispatched by `EventPluginHub`)
* - `S`s extracted events (if any) (dispatched by `EventPluginHub`)
* - `C`s extracted events (if any) (dispatched by `EventPluginHub`)
*
* In the case of `ResponderEventPlugin`: If the `startShouldSetResponder`
* on-demand dispatch returns `true` (and some other details are satisfied) the
* `onResponderGrant` deferred dispatched event is returned from
* `extractEvents`. The sequence of dispatch executions in this case
* will appear as follows:
*
* - `startShouldSetResponder` (`ResponderEventPlugin` dispatches on-demand)
* - `touchStartCapture` (`EventPluginHub` dispatches as usual)
* - `touchStart` (`EventPluginHub` dispatches as usual)
* - `responderGrant/Reject` (`EventPluginHub` dispatches as usual)
*/
function setResponderAndExtractTransfer(topLevelType, targetInst, nativeEvent, nativeEventTarget) {
var shouldSetEventType = isStartish(topLevelType) ? eventTypes.startShouldSetResponder : isMoveish(topLevelType) ? eventTypes.moveShouldSetResponder : topLevelType === 'topSelectionChange' ? eventTypes.selectionChangeShouldSetResponder : eventTypes.scrollShouldSetResponder;
// TODO: stop one short of the current responder.
var bubbleShouldSetFrom = !responderInst ? targetInst : EventPluginUtils.getLowestCommonAncestor(responderInst, targetInst);
// When capturing/bubbling the "shouldSet" event, we want to skip the target
// (deepest ID) if it happens to be the current responder. The reasoning:
// It's strange to get an `onMoveShouldSetResponder` when you're *already*
// the responder.
var skipOverBubbleShouldSetFrom = bubbleShouldSetFrom === responderInst;
var shouldSetEvent = ResponderSyntheticEvent.getPooled(shouldSetEventType, bubbleShouldSetFrom, nativeEvent, nativeEventTarget);
shouldSetEvent.touchHistory = ResponderTouchHistoryStore.touchHistory;
if (skipOverBubbleShouldSetFrom) {
EventPropagators.accumulateTwoPhaseDispatchesSkipTarget(shouldSetEvent);
} else {
EventPropagators.accumulateTwoPhaseDispatches(shouldSetEvent);
}
var wantsResponderInst = executeDispatchesInOrderStopAtTrue(shouldSetEvent);
if (!shouldSetEvent.isPersistent()) {
shouldSetEvent.constructor.release(shouldSetEvent);
}
if (!wantsResponderInst || wantsResponderInst === responderInst) {
return null;
}
var extracted;
var grantEvent = ResponderSyntheticEvent.getPooled(eventTypes.responderGrant, wantsResponderInst, nativeEvent, nativeEventTarget);
grantEvent.touchHistory = ResponderTouchHistoryStore.touchHistory;
EventPropagators.accumulateDirectDispatches(grantEvent);
var blockHostResponder = executeDirectDispatch(grantEvent) === true;
if (responderInst) {
var terminationRequestEvent = ResponderSyntheticEvent.getPooled(eventTypes.responderTerminationRequest, responderInst, nativeEvent, nativeEventTarget);
terminationRequestEvent.touchHistory = ResponderTouchHistoryStore.touchHistory;
EventPropagators.accumulateDirectDispatches(terminationRequestEvent);
var shouldSwitch = !hasDispatches(terminationRequestEvent) || executeDirectDispatch(terminationRequestEvent);
if (!terminationRequestEvent.isPersistent()) {
terminationRequestEvent.constructor.release(terminationRequestEvent);
}
if (shouldSwitch) {
var terminateEvent = ResponderSyntheticEvent.getPooled(eventTypes.responderTerminate, responderInst, nativeEvent, nativeEventTarget);
terminateEvent.touchHistory = ResponderTouchHistoryStore.touchHistory;
EventPropagators.accumulateDirectDispatches(terminateEvent);
extracted = accumulate(extracted, [grantEvent, terminateEvent]);
changeResponder(wantsResponderInst, blockHostResponder);
} else {
var rejectEvent = ResponderSyntheticEvent.getPooled(eventTypes.responderReject, wantsResponderInst, nativeEvent, nativeEventTarget);
rejectEvent.touchHistory = ResponderTouchHistoryStore.touchHistory;
EventPropagators.accumulateDirectDispatches(rejectEvent);
extracted = accumulate(extracted, rejectEvent);
}
} else {
extracted = accumulate(extracted, grantEvent);
changeResponder(wantsResponderInst, blockHostResponder);
}
return extracted;
}
/**
* A transfer is a negotiation between a currently set responder and the next
* element to claim responder status. Any start event could trigger a transfer
* of responderInst. Any move event could trigger a transfer.
*
* @param {string} topLevelType Record from `EventConstants`.
* @return {boolean} True if a transfer of responder could possibly occur.
*/
function canTriggerTransfer(topLevelType, topLevelInst, nativeEvent) {
return topLevelInst && (
// responderIgnoreScroll: We are trying to migrate away from specifically
// tracking native scroll events here and responderIgnoreScroll indicates we
// will send topTouchCancel to handle canceling touch events instead
topLevelType === 'topScroll' && !nativeEvent.responderIgnoreScroll || trackedTouchCount > 0 && topLevelType === 'topSelectionChange' || isStartish(topLevelType) || isMoveish(topLevelType));
}
/**
* Returns whether or not this touch end event makes it such that there are no
* longer any touches that started inside of the current `responderInst`.
*
* @param {NativeEvent} nativeEvent Native touch end event.
* @return {boolean} Whether or not this touch end event ends the responder.
*/
function noResponderTouches(nativeEvent) {
var touches = nativeEvent.touches;
if (!touches || touches.length === 0) {
return true;
}
for (var i = 0; i < touches.length; i++) {
var activeTouch = touches[i];
var target = activeTouch.target;
if (target !== null && target !== undefined && target !== 0) {
// Is the original touch location inside of the current responder?
var targetInst = EventPluginUtils.getInstanceFromNode(target);
if (EventPluginUtils.isAncestor(responderInst, targetInst)) {
return false;
}
}
}
return true;
}
var ResponderEventPlugin = {
/* For unit testing only */
_getResponderID: function () {
return responderInst ? responderInst._rootNodeID : null;
},
eventTypes: eventTypes,
/**
* We must be resilient to `targetInst` being `null` on `touchMove` or
* `touchEnd`. On certain platforms, this means that a native scroll has
* assumed control and the original touch targets are destroyed.
*/
extractEvents: function (topLevelType, targetInst, nativeEvent, nativeEventTarget) {
if (isStartish(topLevelType)) {
trackedTouchCount += 1;
} else if (isEndish(topLevelType)) {
if (trackedTouchCount >= 0) {
trackedTouchCount -= 1;
} else {
console.error('Ended a touch event which was not counted in `trackedTouchCount`.');
return null;
}
}
ResponderTouchHistoryStore.recordTouchTrack(topLevelType, nativeEvent);
var extracted = canTriggerTransfer(topLevelType, targetInst, nativeEvent) ? setResponderAndExtractTransfer(topLevelType, targetInst, nativeEvent, nativeEventTarget) : null;
// Responder may or may not have transferred on a new touch start/move.
// Regardless, whoever is the responder after any potential transfer, we
// direct all touch start/move/ends to them in the form of
// `onResponderMove/Start/End`. These will be called for *every* additional
// finger that move/start/end, dispatched directly to whoever is the
// current responder at that moment, until the responder is "released".
//
// These multiple individual change touch events are are always bookended
// by `onResponderGrant`, and one of
// (`onResponderRelease/onResponderTerminate`).
var isResponderTouchStart = responderInst && isStartish(topLevelType);
var isResponderTouchMove = responderInst && isMoveish(topLevelType);
var isResponderTouchEnd = responderInst && isEndish(topLevelType);
var incrementalTouch = isResponderTouchStart ? eventTypes.responderStart : isResponderTouchMove ? eventTypes.responderMove : isResponderTouchEnd ? eventTypes.responderEnd : null;
if (incrementalTouch) {
var gesture = ResponderSyntheticEvent.getPooled(incrementalTouch, responderInst, nativeEvent, nativeEventTarget);
gesture.touchHistory = ResponderTouchHistoryStore.touchHistory;
EventPropagators.accumulateDirectDispatches(gesture);
extracted = accumulate(extracted, gesture);
}
var isResponderTerminate = responderInst && topLevelType === 'topTouchCancel';
var isResponderRelease = responderInst && !isResponderTerminate && isEndish(topLevelType) && noResponderTouches(nativeEvent);
var finalTouch = isResponderTerminate ? eventTypes.responderTerminate : isResponderRelease ? eventTypes.responderRelease : null;
if (finalTouch) {
var finalEvent = ResponderSyntheticEvent.getPooled(finalTouch, responderInst, nativeEvent, nativeEventTarget);
finalEvent.touchHistory = ResponderTouchHistoryStore.touchHistory;
EventPropagators.accumulateDirectDispatches(finalEvent);
extracted = accumulate(extracted, finalEvent);
changeResponder(null);
}
var numberActiveTouches = ResponderTouchHistoryStore.touchHistory.numberActiveTouches;
if (ResponderEventPlugin.GlobalInteractionHandler && numberActiveTouches !== previousActiveTouches) {
ResponderEventPlugin.GlobalInteractionHandler.onChange(numberActiveTouches);
}
previousActiveTouches = numberActiveTouches;
return extracted;
},
GlobalResponderHandler: null,
GlobalInteractionHandler: null,
injection: {
/**
* @param {{onChange: (ReactID, ReactID) => void} GlobalResponderHandler
* Object that handles any change in responder. Use this to inject
* integration with an existing touch handling system etc.
*/
injectGlobalResponderHandler: function (GlobalResponderHandler) {
ResponderEventPlugin.GlobalResponderHandler = GlobalResponderHandler;
},
/**
* @param {{onChange: (numberActiveTouches) => void} GlobalInteractionHandler
* Object that handles any change in the number of active touches.
*/
injectGlobalInteractionHandler: function (GlobalInteractionHandler) {
ResponderEventPlugin.GlobalInteractionHandler = GlobalInteractionHandler;
}
}
};
module.exports = ResponderEventPlugin;
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