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