181 lines
6.4 KiB
JavaScript
181 lines
6.4 KiB
JavaScript
/**
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* Copyright (c) 2013-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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*
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*/
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'use strict';
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var _prodInvariant = require('./reactProdInvariant');
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var EventPluginUtils = require('./EventPluginUtils');
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var invariant = require('fbjs/lib/invariant');
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var warning = require('fbjs/lib/warning');
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var isEndish = EventPluginUtils.isEndish,
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isMoveish = EventPluginUtils.isMoveish,
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isStartish = EventPluginUtils.isStartish;
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/**
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* Tracks the position and time of each active touch by `touch.identifier`. We
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* should typically only see IDs in the range of 1-20 because IDs get recycled
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* when touches end and start again.
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*/
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var MAX_TOUCH_BANK = 20;
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var touchBank = [];
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var touchHistory = {
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touchBank: touchBank,
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numberActiveTouches: 0,
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// If there is only one active touch, we remember its location. This prevents
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// us having to loop through all of the touches all the time in the most
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// common case.
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indexOfSingleActiveTouch: -1,
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mostRecentTimeStamp: 0
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};
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function timestampForTouch(touch) {
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// The legacy internal implementation provides "timeStamp", which has been
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// renamed to "timestamp". Let both work for now while we iron it out
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// TODO (evv): rename timeStamp to timestamp in internal code
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return touch.timeStamp || touch.timestamp;
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}
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/**
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* TODO: Instead of making gestures recompute filtered velocity, we could
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* include a built in velocity computation that can be reused globally.
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*/
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function createTouchRecord(touch) {
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return {
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touchActive: true,
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startPageX: touch.pageX,
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startPageY: touch.pageY,
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startTimeStamp: timestampForTouch(touch),
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currentPageX: touch.pageX,
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currentPageY: touch.pageY,
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currentTimeStamp: timestampForTouch(touch),
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previousPageX: touch.pageX,
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previousPageY: touch.pageY,
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previousTimeStamp: timestampForTouch(touch)
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};
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}
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function resetTouchRecord(touchRecord, touch) {
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touchRecord.touchActive = true;
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touchRecord.startPageX = touch.pageX;
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touchRecord.startPageY = touch.pageY;
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touchRecord.startTimeStamp = timestampForTouch(touch);
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touchRecord.currentPageX = touch.pageX;
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touchRecord.currentPageY = touch.pageY;
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touchRecord.currentTimeStamp = timestampForTouch(touch);
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touchRecord.previousPageX = touch.pageX;
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touchRecord.previousPageY = touch.pageY;
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touchRecord.previousTimeStamp = timestampForTouch(touch);
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}
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function getTouchIdentifier(_ref) {
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var identifier = _ref.identifier;
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!(identifier != null) ? process.env.NODE_ENV !== 'production' ? invariant(false, 'Touch object is missing identifier.') : _prodInvariant('138') : void 0;
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process.env.NODE_ENV !== 'production' ? warning(identifier <= MAX_TOUCH_BANK, 'Touch identifier %s is greater than maximum supported %s which causes ' + 'performance issues backfilling array locations for all of the indices.', identifier, MAX_TOUCH_BANK) : void 0;
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return identifier;
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}
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function recordTouchStart(touch) {
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var identifier = getTouchIdentifier(touch);
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var touchRecord = touchBank[identifier];
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if (touchRecord) {
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resetTouchRecord(touchRecord, touch);
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} else {
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touchBank[identifier] = createTouchRecord(touch);
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}
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touchHistory.mostRecentTimeStamp = timestampForTouch(touch);
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}
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function recordTouchMove(touch) {
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var touchRecord = touchBank[getTouchIdentifier(touch)];
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if (touchRecord) {
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touchRecord.touchActive = true;
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touchRecord.previousPageX = touchRecord.currentPageX;
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touchRecord.previousPageY = touchRecord.currentPageY;
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touchRecord.previousTimeStamp = touchRecord.currentTimeStamp;
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touchRecord.currentPageX = touch.pageX;
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touchRecord.currentPageY = touch.pageY;
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touchRecord.currentTimeStamp = timestampForTouch(touch);
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touchHistory.mostRecentTimeStamp = timestampForTouch(touch);
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} else {
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console.error('Cannot record touch move without a touch start.\n' + 'Touch Move: %s\n', 'Touch Bank: %s', printTouch(touch), printTouchBank());
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}
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}
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function recordTouchEnd(touch) {
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var touchRecord = touchBank[getTouchIdentifier(touch)];
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if (touchRecord) {
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touchRecord.touchActive = false;
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touchRecord.previousPageX = touchRecord.currentPageX;
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touchRecord.previousPageY = touchRecord.currentPageY;
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touchRecord.previousTimeStamp = touchRecord.currentTimeStamp;
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touchRecord.currentPageX = touch.pageX;
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touchRecord.currentPageY = touch.pageY;
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touchRecord.currentTimeStamp = timestampForTouch(touch);
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touchHistory.mostRecentTimeStamp = timestampForTouch(touch);
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} else {
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console.error('Cannot record touch end without a touch start.\n' + 'Touch End: %s\n', 'Touch Bank: %s', printTouch(touch), printTouchBank());
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}
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}
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function printTouch(touch) {
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return JSON.stringify({
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identifier: touch.identifier,
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pageX: touch.pageX,
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pageY: touch.pageY,
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timestamp: timestampForTouch(touch)
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});
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}
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function printTouchBank() {
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var printed = JSON.stringify(touchBank.slice(0, MAX_TOUCH_BANK));
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if (touchBank.length > MAX_TOUCH_BANK) {
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printed += ' (original size: ' + touchBank.length + ')';
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}
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return printed;
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}
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var ResponderTouchHistoryStore = {
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recordTouchTrack: function (topLevelType, nativeEvent) {
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if (isMoveish(topLevelType)) {
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nativeEvent.changedTouches.forEach(recordTouchMove);
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} else if (isStartish(topLevelType)) {
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nativeEvent.changedTouches.forEach(recordTouchStart);
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touchHistory.numberActiveTouches = nativeEvent.touches.length;
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if (touchHistory.numberActiveTouches === 1) {
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touchHistory.indexOfSingleActiveTouch = nativeEvent.touches[0].identifier;
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}
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} else if (isEndish(topLevelType)) {
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nativeEvent.changedTouches.forEach(recordTouchEnd);
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touchHistory.numberActiveTouches = nativeEvent.touches.length;
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if (touchHistory.numberActiveTouches === 1) {
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for (var i = 0; i < touchBank.length; i++) {
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var touchTrackToCheck = touchBank[i];
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if (touchTrackToCheck != null && touchTrackToCheck.touchActive) {
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touchHistory.indexOfSingleActiveTouch = i;
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break;
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}
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}
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if (process.env.NODE_ENV !== 'production') {
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var activeRecord = touchBank[touchHistory.indexOfSingleActiveTouch];
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process.env.NODE_ENV !== 'production' ? warning(activeRecord != null && activeRecord.touchActive, 'Cannot find single active touch.') : void 0;
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}
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}
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}
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},
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touchHistory: touchHistory
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};
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module.exports = ResponderTouchHistoryStore; |