83 lines
2.0 KiB
JavaScript
83 lines
2.0 KiB
JavaScript
/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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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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* @emails react-core
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*/
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'use strict';
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/**
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* Touch events state machine.
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*
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* Keeps track of the active pointers and allows them to be reflected in touch events.
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*/
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const activeTouches = new Map();
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export function addTouch(touch) {
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const identifier = touch.identifier;
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const target = touch.target;
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if (!activeTouches.has(target)) {
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activeTouches.set(target, new Map());
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}
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if (activeTouches.get(target).get(identifier)) {
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// Do not allow existing touches to be overwritten
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console.error(
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'Touch with identifier %s already exists. Did not record touch start.',
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identifier,
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);
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} else {
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activeTouches.get(target).set(identifier, touch);
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}
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}
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export function updateTouch(touch) {
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const identifier = touch.identifier;
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const target = touch.target;
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if (activeTouches.get(target) != null) {
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activeTouches.get(target).set(identifier, touch);
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} else {
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console.error(
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'Touch with identifier %s does not exist. Cannot record touch move without a touch start.',
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identifier,
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);
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}
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}
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export function removeTouch(touch) {
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const identifier = touch.identifier;
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const target = touch.target;
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if (activeTouches.get(target) != null) {
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if (activeTouches.get(target).has(identifier)) {
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activeTouches.get(target).delete(identifier);
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} else {
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console.error(
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'Touch with identifier %s does not exist. Cannot record touch end without a touch start.',
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identifier,
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);
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}
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}
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}
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export function getTouches() {
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const touches = [];
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activeTouches.forEach((_, target) => {
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touches.push(...getTargetTouches(target));
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});
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return touches;
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}
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export function getTargetTouches(target) {
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if (activeTouches.get(target) != null) {
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return Array.from(activeTouches.get(target).values());
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}
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return [];
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}
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export function clear() {
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activeTouches.clear();
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}
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