yeet

node_modules/react-native/Libraries/Interaction/Batchinator.js

@@ -0,0 +1,76 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow strict-local
+ */
+
+'use strict';
+
+const InteractionManager = require('./InteractionManager');
+
+/**
+ * A simple class for batching up invocations of a low-pri callback. A timeout is set to run the
+ * callback once after a delay, no matter how many times it's scheduled. Once the delay is reached,
+ * InteractionManager.runAfterInteractions is used to invoke the callback after any hi-pri
+ * interactions are done running.
+ *
+ * Make sure to cleanup with dispose().  Example:
+ *
+ *   class Widget extends React.Component {
+ *     _batchedSave: new Batchinator(() => this._saveState, 1000);
+ *     _saveSate() {
+ *       // save this.state to disk
+ *     }
+ *     componentDidUpdate() {
+ *       this._batchedSave.schedule();
+ *     }
+ *     componentWillUnmount() {
+ *       this._batchedSave.dispose();
+ *     }
+ *     ...
+ *   }
+ */
+class Batchinator {
+  _callback: () => void;
+  _delay: number;
+  _taskHandle: ?{cancel: () => void, ...};
+  constructor(callback: () => void, delayMS: number) {
+    this._delay = delayMS;
+    this._callback = callback;
+  }
+  /*
+   * Cleanup any pending tasks.
+   *
+   * By default, if there is a pending task the callback is run immediately. Set the option abort to
+   * true to not call the callback if it was pending.
+   */
+  dispose(options: {abort: boolean, ...} = {abort: false}) {
+    if (this._taskHandle) {
+      this._taskHandle.cancel();
+      if (!options.abort) {
+        this._callback();
+      }
+      this._taskHandle = null;
+    }
+  }
+  schedule() {
+    if (this._taskHandle) {
+      return;
+    }
+    const timeoutHandle = setTimeout(() => {
+      this._taskHandle = InteractionManager.runAfterInteractions(() => {
+        // Note that we clear the handle before invoking the callback so that if the callback calls
+        // schedule again, it will actually schedule another task.
+        this._taskHandle = null;
+        this._callback();
+      });
+    }, this._delay);
+    this._taskHandle = {cancel: () => clearTimeout(timeoutHandle)};
+  }
+}
+
+module.exports = Batchinator;

node_modules/react-native/Libraries/Interaction/BridgeSpyStallHandler.js

@@ -0,0 +1,62 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow
+ */
+
+'use strict';
+
+const JSEventLoopWatchdog = require('./JSEventLoopWatchdog');
+const MessageQueue = require('../BatchedBridge/MessageQueue');
+
+const infoLog = require('../Utilities/infoLog');
+
+const BridgeSpyStallHandler = {
+  register: function() {
+    let spyBuffer = [];
+    MessageQueue.spy(data => {
+      spyBuffer.push(data);
+    });
+    const TO_JS = 0;
+    JSEventLoopWatchdog.addHandler({
+      onStall: () => {
+        infoLog(
+          spyBuffer.length + ' bridge messages during stall: ',
+          spyBuffer.map(info => {
+            let args = '<args>';
+            try {
+              args = JSON.stringify(info.args);
+            } catch (e1) {
+              if (Array.isArray(info.args)) {
+                args = info.args.map(arg => {
+                  try {
+                    return JSON.stringify(arg);
+                  } catch (e2) {
+                    return '?';
+                  }
+                });
+              } else {
+                args = 'keys:' + JSON.stringify(Object.keys(info.args));
+              }
+            }
+            return (
+              `${info.type === TO_JS ? 'N->JS' : 'JS->N'} : ` +
+              `${info.module ? info.module + '.' : ''}${
+                info.method
+              }(${JSON.stringify(args)})`
+            );
+          }),
+        );
+      },
+      onIterate: () => {
+        spyBuffer = [];
+      },
+    });
+  },
+};
+
+module.exports = BridgeSpyStallHandler;

node_modules/react-native/Libraries/Interaction/FrameRateLogger.js

@@ -0,0 +1,84 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow strict-local
+ */
+
+'use strict';
+
+import NativeFrameRateLogger from './NativeFrameRateLogger';
+
+const invariant = require('invariant');
+
+/**
+ * Flow API for native FrameRateLogger module. If the native module is not installed, function calls
+ * are just no-ops.
+ *
+ * Typical behavior is that `setContext` is called when a new screen is loaded (e.g. via a
+ * navigation integration), and then `beginScroll` is called by `ScrollResponder` at which point the
+ * native module then begins tracking frame drops. When `ScrollResponder` calls `endScroll`, the
+ * native module gathers up all it's frame drop data and reports it via an analytics pipeline for
+ * analysis.
+ *
+ * Note that `beginScroll` may be called multiple times by `ScrollResponder` - unclear if that's a
+ * bug, but the native module should be robust to that.
+ *
+ * In the future we may add support for tracking frame drops in other types of interactions beyond
+ * scrolling.
+ */
+const FrameRateLogger = {
+  /**
+   * Enable `debug` to see local logs of what's going on. `reportStackTraces` will grab stack traces
+   * during UI thread stalls and upload them if the native module supports it.
+   */
+  setGlobalOptions: function(options: {
+    debug?: boolean,
+    reportStackTraces?: boolean,
+    ...
+  }) {
+    if (options.debug !== undefined) {
+      invariant(
+        NativeFrameRateLogger,
+        'Trying to debug FrameRateLogger without the native module!',
+      );
+    }
+    if (NativeFrameRateLogger) {
+      // Needs to clone the object first to avoid modifying the argument.
+      const optionsClone = {
+        debug: !!options.debug,
+        reportStackTraces: !!options.reportStackTraces,
+      };
+      NativeFrameRateLogger.setGlobalOptions(optionsClone);
+    }
+  },
+
+  /**
+   * Must call `setContext` before any events can be properly tracked, which is done automatically
+   * in `AppRegistry`, but navigation is also a common place to hook in.
+   */
+  setContext: function(context: string) {
+    NativeFrameRateLogger && NativeFrameRateLogger.setContext(context);
+  },
+
+  /**
+   * Called in `ScrollResponder` so any component that uses that module will handle this
+   * automatically.
+   */
+  beginScroll() {
+    NativeFrameRateLogger && NativeFrameRateLogger.beginScroll();
+  },
+
+  /**
+   * Called in `ScrollResponder` so any component that uses that module will handle this
+   * automatically.
+   */
+  endScroll() {
+    NativeFrameRateLogger && NativeFrameRateLogger.endScroll();
+  },
+};
+
+module.exports = FrameRateLogger;

node_modules/react-native/Libraries/Interaction/InteractionManager.js

@@ -0,0 +1,222 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow
+ */
+
+'use strict';
+
+const BatchedBridge = require('../BatchedBridge/BatchedBridge');
+const EventEmitter = require('../vendor/emitter/EventEmitter');
+const TaskQueue = require('./TaskQueue');
+
+const infoLog = require('../Utilities/infoLog');
+const invariant = require('invariant');
+const keyMirror = require('fbjs/lib/keyMirror');
+
+export type Handle = number;
+import type {Task} from './TaskQueue';
+
+const _emitter = new EventEmitter();
+
+const DEBUG_DELAY: 0 = 0;
+const DEBUG: false = false;
+
+/**
+ * InteractionManager allows long-running work to be scheduled after any
+ * interactions/animations have completed. In particular, this allows JavaScript
+ * animations to run smoothly.
+ *
+ * Applications can schedule tasks to run after interactions with the following:
+ *
+ * ```
+ * InteractionManager.runAfterInteractions(() => {
+ *   // ...long-running synchronous task...
+ * });
+ * ```
+ *
+ * Compare this to other scheduling alternatives:
+ *
+ * - requestAnimationFrame(): for code that animates a view over time.
+ * - setImmediate/setTimeout(): run code later, note this may delay animations.
+ * - runAfterInteractions(): run code later, without delaying active animations.
+ *
+ * The touch handling system considers one or more active touches to be an
+ * 'interaction' and will delay `runAfterInteractions()` callbacks until all
+ * touches have ended or been cancelled.
+ *
+ * InteractionManager also allows applications to register animations by
+ * creating an interaction 'handle' on animation start, and clearing it upon
+ * completion:
+ *
+ * ```
+ * var handle = InteractionManager.createInteractionHandle();
+ * // run animation... (`runAfterInteractions` tasks are queued)
+ * // later, on animation completion:
+ * InteractionManager.clearInteractionHandle(handle);
+ * // queued tasks run if all handles were cleared
+ * ```
+ *
+ * `runAfterInteractions` takes either a plain callback function, or a
+ * `PromiseTask` object with a `gen` method that returns a `Promise`.  If a
+ * `PromiseTask` is supplied, then it is fully resolved (including asynchronous
+ * dependencies that also schedule more tasks via `runAfterInteractions`) before
+ * starting on the next task that might have been queued up synchronously
+ * earlier.
+ *
+ * By default, queued tasks are executed together in a loop in one
+ * `setImmediate` batch. If `setDeadline` is called with a positive number, then
+ * tasks will only be executed until the deadline (in terms of js event loop run
+ * time) approaches, at which point execution will yield via setTimeout,
+ * allowing events such as touches to start interactions and block queued tasks
+ * from executing, making apps more responsive.
+ */
+const InteractionManager = {
+  Events: keyMirror({
+    interactionStart: true,
+    interactionComplete: true,
+  }),
+
+  /**
+   * Schedule a function to run after all interactions have completed. Returns a cancellable
+   * "promise".
+   */
+  runAfterInteractions(
+    task: ?Task,
+  ): {
+    then: Function,
+    done: Function,
+    cancel: Function,
+    ...
+  } {
+    const tasks = [];
+    const promise = new Promise(resolve => {
+      _scheduleUpdate();
+      if (task) {
+        tasks.push(task);
+      }
+      tasks.push({
+        run: resolve,
+        name: 'resolve ' + ((task && task.name) || '?'),
+      });
+      _taskQueue.enqueueTasks(tasks);
+    });
+    return {
+      then: promise.then.bind(promise),
+      done: (...args) => {
+        if (promise.done) {
+          return promise.done(...args);
+        } else {
+          console.warn(
+            'Tried to call done when not supported by current Promise implementation.',
+          );
+        }
+      },
+      cancel: function() {
+        _taskQueue.cancelTasks(tasks);
+      },
+    };
+  },
+
+  /**
+   * Notify manager that an interaction has started.
+   */
+  createInteractionHandle(): Handle {
+    DEBUG && infoLog('InteractionManager: create interaction handle');
+    _scheduleUpdate();
+    const handle = ++_inc;
+    _addInteractionSet.add(handle);
+    return handle;
+  },
+
+  /**
+   * Notify manager that an interaction has completed.
+   */
+  clearInteractionHandle(handle: Handle) {
+    DEBUG && infoLog('InteractionManager: clear interaction handle');
+    invariant(!!handle, 'InteractionManager: Must provide a handle to clear.');
+    _scheduleUpdate();
+    _addInteractionSet.delete(handle);
+    _deleteInteractionSet.add(handle);
+  },
+
+  addListener: (_emitter.addListener.bind(_emitter): $FlowFixMe),
+
+  /**
+   * A positive number will use setTimeout to schedule any tasks after the
+   * eventLoopRunningTime hits the deadline value, otherwise all tasks will be
+   * executed in one setImmediate batch (default).
+   */
+  setDeadline(deadline: number) {
+    _deadline = deadline;
+  },
+};
+
+const _interactionSet = new Set();
+const _addInteractionSet = new Set();
+const _deleteInteractionSet = new Set();
+const _taskQueue = new TaskQueue({onMoreTasks: _scheduleUpdate});
+let _nextUpdateHandle = 0;
+let _inc = 0;
+let _deadline = -1;
+
+declare function setImmediate(callback: any, ...args: Array<any>): number;
+
+/**
+ * Schedule an asynchronous update to the interaction state.
+ */
+function _scheduleUpdate() {
+  if (!_nextUpdateHandle) {
+    if (_deadline > 0) {
+      /* $FlowFixMe(>=0.63.0 site=react_native_fb) This comment suppresses an
+       * error found when Flow v0.63 was deployed. To see the error delete this
+       * comment and run Flow. */
+      _nextUpdateHandle = setTimeout(_processUpdate, 0 + DEBUG_DELAY);
+    } else {
+      _nextUpdateHandle = setImmediate(_processUpdate);
+    }
+  }
+}
+
+/**
+ * Notify listeners, process queue, etc
+ */
+function _processUpdate() {
+  _nextUpdateHandle = 0;
+
+  const interactionCount = _interactionSet.size;
+  _addInteractionSet.forEach(handle => _interactionSet.add(handle));
+  _deleteInteractionSet.forEach(handle => _interactionSet.delete(handle));
+  const nextInteractionCount = _interactionSet.size;
+
+  if (interactionCount !== 0 && nextInteractionCount === 0) {
+    // transition from 1+ --> 0 interactions
+    _emitter.emit(InteractionManager.Events.interactionComplete);
+  } else if (interactionCount === 0 && nextInteractionCount !== 0) {
+    // transition from 0 --> 1+ interactions
+    _emitter.emit(InteractionManager.Events.interactionStart);
+  }
+
+  // process the queue regardless of a transition
+  if (nextInteractionCount === 0) {
+    while (_taskQueue.hasTasksToProcess()) {
+      _taskQueue.processNext();
+      if (
+        _deadline > 0 &&
+        BatchedBridge.getEventLoopRunningTime() >= _deadline
+      ) {
+        // Hit deadline before processing all tasks, so process more later.
+        _scheduleUpdate();
+        break;
+      }
+    }
+  }
+  _addInteractionSet.clear();
+  _deleteInteractionSet.clear();
+}
+
+module.exports = InteractionManager;

node_modules/react-native/Libraries/Interaction/InteractionMixin.js

@@ -0,0 +1,55 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow
+ */
+
+'use strict';
+
+const InteractionManager = require('./InteractionManager');
+import {type Handle} from './InteractionManager';
+
+/**
+ * This mixin provides safe versions of InteractionManager start/end methods
+ * that ensures `clearInteractionHandle` is always called
+ * once per start, even if the component is unmounted.
+ */
+const InteractionMixin = {
+  componentWillUnmount: function() {
+    while (this._interactionMixinHandles.length) {
+      InteractionManager.clearInteractionHandle(
+        this._interactionMixinHandles.pop(),
+      );
+    }
+  },
+
+  _interactionMixinHandles: ([]: Array<number>),
+
+  createInteractionHandle: function(): Handle {
+    const handle = InteractionManager.createInteractionHandle();
+    this._interactionMixinHandles.push(handle);
+    return handle;
+  },
+
+  clearInteractionHandle: function(clearHandle: number): void {
+    InteractionManager.clearInteractionHandle(clearHandle);
+    this._interactionMixinHandles = this._interactionMixinHandles.filter(
+      handle => handle !== clearHandle,
+    );
+  },
+
+  /**
+   * Schedule work for after all interactions have completed.
+   *
+   * @param {function} callback
+   */
+  runAfterInteractions: function(callback: Function): void {
+    InteractionManager.runAfterInteractions(callback);
+  },
+};
+
+module.exports = InteractionMixin;

node_modules/react-native/Libraries/Interaction/InteractionStallDebugger.js

@@ -0,0 +1,23 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow strict-local
+ */
+
+'use strict';
+
+const BridgeSpyStallHandler = require('./BridgeSpyStallHandler');
+const JSEventLoopWatchdog = require('./JSEventLoopWatchdog');
+
+const InteractionStallDebugger = {
+  install(options: {thresholdMS: number, ...}): void {
+    JSEventLoopWatchdog.install(options);
+    BridgeSpyStallHandler.register();
+  },
+};
+
+module.exports = InteractionStallDebugger;

node_modules/react-native/Libraries/Interaction/JSEventLoopWatchdog.js

@@ -0,0 +1,93 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow
+ */
+
+'use strict';
+
+const infoLog = require('../Utilities/infoLog');
+const performanceNow = require('fbjs/lib/performanceNow');
+
+type Handler = {
+  onIterate?: () => void,
+  onStall: (params: {
+    lastInterval: number,
+    busyTime: number,
+    ...
+  }) => ?string,
+  ...
+};
+
+/**
+ * A utility for tracking stalls in the JS event loop that prevent timers and
+ * other events from being processed in a timely manner.
+ *
+ * The "stall" time is defined as the amount of time in access of the acceptable
+ * threshold, which is typically around 100-200ms. So if the treshold is set to
+ * 100 and a timer fires 150 ms later than it was scheduled because the event
+ * loop was tied up, that would be considered a 50ms stall.
+ *
+ * By default, logs stall events to the console when installed. Can also be
+ * queried with `getStats`.
+ */
+const JSEventLoopWatchdog = {
+  getStats: function(): Object {
+    return {stallCount, totalStallTime, longestStall, acceptableBusyTime};
+  },
+  reset: function() {
+    infoLog('JSEventLoopWatchdog: reset');
+    totalStallTime = 0;
+    stallCount = 0;
+    longestStall = 0;
+    lastInterval = performanceNow();
+  },
+  addHandler: function(handler: Handler) {
+    handlers.push(handler);
+  },
+  install: function({thresholdMS}: {thresholdMS: number, ...}) {
+    acceptableBusyTime = thresholdMS;
+    if (installed) {
+      return;
+    }
+    installed = true;
+    lastInterval = performanceNow();
+    function iteration() {
+      const now = performanceNow();
+      const busyTime = now - lastInterval;
+      if (busyTime >= thresholdMS) {
+        const stallTime = busyTime - thresholdMS;
+        stallCount++;
+        totalStallTime += stallTime;
+        longestStall = Math.max(longestStall, stallTime);
+        let msg =
+          `JSEventLoopWatchdog: JS thread busy for ${busyTime}ms. ` +
+          `${totalStallTime}ms in ${stallCount} stalls so far. `;
+        handlers.forEach(handler => {
+          msg += handler.onStall({lastInterval, busyTime}) || '';
+        });
+        infoLog(msg);
+      }
+      handlers.forEach(handler => {
+        handler.onIterate && handler.onIterate();
+      });
+      lastInterval = now;
+      setTimeout(iteration, thresholdMS / 5);
+    }
+    iteration();
+  },
+};
+
+let acceptableBusyTime = 0;
+let installed = false;
+let totalStallTime = 0;
+let stallCount = 0;
+let longestStall = 0;
+let lastInterval = 0;
+const handlers: Array<Handler> = [];
+
+module.exports = JSEventLoopWatchdog;

node_modules/react-native/Libraries/Interaction/NativeFrameRateLogger.js

@@ -0,0 +1,24 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow strict-local
+ */
+
+import type {TurboModule} from '../TurboModule/RCTExport';
+import * as TurboModuleRegistry from '../TurboModule/TurboModuleRegistry';
+
+export interface Spec extends TurboModule {
+  +setGlobalOptions: (options: {|
+    +debug?: ?boolean,
+    +reportStackTraces?: ?boolean,
+  |}) => void;
+  +setContext: (context: string) => void;
+  +beginScroll: () => void;
+  +endScroll: () => void;
+}
+
+export default (TurboModuleRegistry.get<Spec>('FrameRateLogger'): ?Spec);

node_modules/react-native/Libraries/Interaction/PanResponder.js

@@ -0,0 +1,581 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ * @format
+ */
+
+'use strict';
+
+const InteractionManager = require('./InteractionManager');
+const TouchHistoryMath = require('./TouchHistoryMath');
+
+import type {PressEvent} from '../Types/CoreEventTypes';
+
+const currentCentroidXOfTouchesChangedAfter =
+  TouchHistoryMath.currentCentroidXOfTouchesChangedAfter;
+const currentCentroidYOfTouchesChangedAfter =
+  TouchHistoryMath.currentCentroidYOfTouchesChangedAfter;
+const previousCentroidXOfTouchesChangedAfter =
+  TouchHistoryMath.previousCentroidXOfTouchesChangedAfter;
+const previousCentroidYOfTouchesChangedAfter =
+  TouchHistoryMath.previousCentroidYOfTouchesChangedAfter;
+const currentCentroidX = TouchHistoryMath.currentCentroidX;
+const currentCentroidY = TouchHistoryMath.currentCentroidY;
+
+/**
+ * `PanResponder` reconciles several touches into a single gesture. It makes
+ * single-touch gestures resilient to extra touches, and can be used to
+ * recognize simple multi-touch gestures.
+ *
+ * By default, `PanResponder` holds an `InteractionManager` handle to block
+ * long-running JS events from interrupting active gestures.
+ *
+ * It provides a predictable wrapper of the responder handlers provided by the
+ * [gesture responder system](docs/gesture-responder-system.html).
+ * For each handler, it provides a new `gestureState` object alongside the
+ * native event object:
+ *
+ * ```
+ * onPanResponderMove: (event, gestureState) => {}
+ * ```
+ *
+ * A native event is a synthetic touch event with the following form:
+ *
+ *  - `nativeEvent`
+ *      + `changedTouches` - Array of all touch events that have changed since the last event
+ *      + `identifier` - The ID of the touch
+ *      + `locationX` - The X position of the touch, relative to the element
+ *      + `locationY` - The Y position of the touch, relative to the element
+ *      + `pageX` - The X position of the touch, relative to the root element
+ *      + `pageY` - The Y position of the touch, relative to the root element
+ *      + `target` - The node id of the element receiving the touch event
+ *      + `timestamp` - A time identifier for the touch, useful for velocity calculation
+ *      + `touches` - Array of all current touches on the screen
+ *
+ * A `gestureState` object has the following:
+ *
+ *  - `stateID` - ID of the gestureState- persisted as long as there at least
+ *     one touch on screen
+ *  - `moveX` - the latest screen coordinates of the recently-moved touch
+ *  - `moveY` - the latest screen coordinates of the recently-moved touch
+ *  - `x0` - the screen coordinates of the responder grant
+ *  - `y0` - the screen coordinates of the responder grant
+ *  - `dx` - accumulated distance of the gesture since the touch started
+ *  - `dy` - accumulated distance of the gesture since the touch started
+ *  - `vx` - current velocity of the gesture
+ *  - `vy` - current velocity of the gesture
+ *  - `numberActiveTouches` - Number of touches currently on screen
+ *
+ * ### Basic Usage
+ *
+ * ```
+ *   componentWillMount: function() {
+ *     this._panResponder = PanResponder.create({
+ *       // Ask to be the responder:
+ *       onStartShouldSetPanResponder: (evt, gestureState) => true,
+ *       onStartShouldSetPanResponderCapture: (evt, gestureState) => true,
+ *       onMoveShouldSetPanResponder: (evt, gestureState) => true,
+ *       onMoveShouldSetPanResponderCapture: (evt, gestureState) => true,
+ *
+ *       onPanResponderGrant: (evt, gestureState) => {
+ *         // The gesture has started. Show visual feedback so the user knows
+ *         // what is happening!
+ *
+ *         // gestureState.d{x,y} will be set to zero now
+ *       },
+ *       onPanResponderMove: (evt, gestureState) => {
+ *         // The most recent move distance is gestureState.move{X,Y}
+ *
+ *         // The accumulated gesture distance since becoming responder is
+ *         // gestureState.d{x,y}
+ *       },
+ *       onPanResponderTerminationRequest: (evt, gestureState) => true,
+ *       onPanResponderRelease: (evt, gestureState) => {
+ *         // The user has released all touches while this view is the
+ *         // responder. This typically means a gesture has succeeded
+ *       },
+ *       onPanResponderTerminate: (evt, gestureState) => {
+ *         // Another component has become the responder, so this gesture
+ *         // should be cancelled
+ *       },
+ *       onShouldBlockNativeResponder: (evt, gestureState) => {
+ *         // Returns whether this component should block native components from becoming the JS
+ *         // responder. Returns true by default. Is currently only supported on android.
+ *         return true;
+ *       },
+ *     });
+ *   },
+ *
+ *   render: function() {
+ *     return (
+ *       <View {...this._panResponder.panHandlers} />
+ *     );
+ *   },
+ *
+ * ```
+ *
+ * ### Working Example
+ *
+ * To see it in action, try the
+ * [PanResponder example in RNTester](https://github.com/facebook/react-native/blob/master/RNTester/js/PanResponderExample.js)
+ */
+
+export type GestureState = {|
+  /**
+   * ID of the gestureState - persisted as long as there at least one touch on screen
+   */
+  stateID: number,
+
+  /**
+   * The latest screen coordinates of the recently-moved touch
+   */
+  moveX: number,
+
+  /**
+   * The latest screen coordinates of the recently-moved touch
+   */
+  moveY: number,
+
+  /**
+   * The screen coordinates of the responder grant
+   */
+  x0: number,
+
+  /**
+   * The screen coordinates of the responder grant
+   */
+  y0: number,
+
+  /**
+   * Accumulated distance of the gesture since the touch started
+   */
+  dx: number,
+
+  /**
+   * Accumulated distance of the gesture since the touch started
+   */
+  dy: number,
+
+  /**
+   * Current velocity of the gesture
+   */
+  vx: number,
+
+  /**
+   * Current velocity of the gesture
+   */
+  vy: number,
+
+  /**
+   * Number of touches currently on screen
+   */
+  numberActiveTouches: number,
+
+  /**
+   * All `gestureState` accounts for timeStamps up until this value
+   *
+   * @private
+   */
+  _accountsForMovesUpTo: number,
+|};
+
+type ActiveCallback = (
+  event: PressEvent,
+  gestureState: GestureState,
+) => boolean;
+
+type PassiveCallback = (event: PressEvent, gestureState: GestureState) => mixed;
+
+type PanResponderConfig = $ReadOnly<{|
+  onMoveShouldSetPanResponder?: ?ActiveCallback,
+  onMoveShouldSetPanResponderCapture?: ?ActiveCallback,
+  onStartShouldSetPanResponder?: ?ActiveCallback,
+  onStartShouldSetPanResponderCapture?: ?ActiveCallback,
+  /**
+   * The body of `onResponderGrant` returns a bool, but the vast majority of
+   * callsites return void and this TODO notice is found in it:
+   *   TODO: t7467124 investigate if this can be removed
+   */
+  onPanResponderGrant?: ?(PassiveCallback | ActiveCallback),
+  onPanResponderReject?: ?PassiveCallback,
+  onPanResponderStart?: ?PassiveCallback,
+  onPanResponderEnd?: ?PassiveCallback,
+  onPanResponderRelease?: ?PassiveCallback,
+  onPanResponderMove?: ?PassiveCallback,
+  onPanResponderTerminate?: ?PassiveCallback,
+  onPanResponderTerminationRequest?: ?ActiveCallback,
+  onShouldBlockNativeResponder?: ?ActiveCallback,
+|}>;
+
+const PanResponder = {
+  /**
+   *
+   * A graphical explanation of the touch data flow:
+   *
+   * +----------------------------+             +--------------------------------+
+   * | ResponderTouchHistoryStore |             |TouchHistoryMath                |
+   * +----------------------------+             +----------+---------------------+
+   * |Global store of touchHistory|             |Allocation-less math util       |
+   * |including activeness, start |             |on touch history (centroids     |
+   * |position, prev/cur position.|             |and multitouch movement etc)    |
+   * |                            |             |                                |
+   * +----^-----------------------+             +----^---------------------------+
+   *      |                                          |
+   *      | (records relevant history                |
+   *      |  of touches relevant for                 |
+   *      |  implementing higher level               |
+   *      |  gestures)                               |
+   *      |                                          |
+   * +----+-----------------------+             +----|---------------------------+
+   * | ResponderEventPlugin       |             |    |   Your App/Component      |
+   * +----------------------------+             +----|---------------------------+
+   * |Negotiates which view gets  | Low level   |    |             High level    |
+   * |onResponderMove events.     | events w/   |  +-+-------+     events w/     |
+   * |Also records history into   | touchHistory|  |   Pan   |     multitouch +  |
+   * |ResponderTouchHistoryStore. +---------------->Responder+-----> accumulative|
+   * +----------------------------+ attached to |  |         |     distance and  |
+   *                                 each event |  +---------+     velocity.     |
+   *                                            |                                |
+   *                                            |                                |
+   *                                            +--------------------------------+
+   *
+   *
+   *
+   * Gesture that calculates cumulative movement over time in a way that just
+   * "does the right thing" for multiple touches. The "right thing" is very
+   * nuanced. When moving two touches in opposite directions, the cumulative
+   * distance is zero in each dimension. When two touches move in parallel five
+   * pixels in the same direction, the cumulative distance is five, not ten. If
+   * two touches start, one moves five in a direction, then stops and the other
+   * touch moves fives in the same direction, the cumulative distance is ten.
+   *
+   * This logic requires a kind of processing of time "clusters" of touch events
+   * so that two touch moves that essentially occur in parallel but move every
+   * other frame respectively, are considered part of the same movement.
+   *
+   * Explanation of some of the non-obvious fields:
+   *
+   * - moveX/moveY: If no move event has been observed, then `(moveX, moveY)` is
+   *   invalid. If a move event has been observed, `(moveX, moveY)` is the
+   *   centroid of the most recently moved "cluster" of active touches.
+   *   (Currently all move have the same timeStamp, but later we should add some
+   *   threshold for what is considered to be "moving"). If a palm is
+   *   accidentally counted as a touch, but a finger is moving greatly, the palm
+   *   will move slightly, but we only want to count the single moving touch.
+   * - x0/y0: Centroid location (non-cumulative) at the time of becoming
+   *   responder.
+   * - dx/dy: Cumulative touch distance - not the same thing as sum of each touch
+   *   distance. Accounts for touch moves that are clustered together in time,
+   *   moving the same direction. Only valid when currently responder (otherwise,
+   *   it only represents the drag distance below the threshold).
+   * - vx/vy: Velocity.
+   */
+
+  _initializeGestureState(gestureState: GestureState) {
+    gestureState.moveX = 0;
+    gestureState.moveY = 0;
+    gestureState.x0 = 0;
+    gestureState.y0 = 0;
+    gestureState.dx = 0;
+    gestureState.dy = 0;
+    gestureState.vx = 0;
+    gestureState.vy = 0;
+    gestureState.numberActiveTouches = 0;
+    // All `gestureState` accounts for timeStamps up until:
+    gestureState._accountsForMovesUpTo = 0;
+  },
+
+  /**
+   * This is nuanced and is necessary. It is incorrect to continuously take all
+   * active *and* recently moved touches, find the centroid, and track how that
+   * result changes over time. Instead, we must take all recently moved
+   * touches, and calculate how the centroid has changed just for those
+   * recently moved touches, and append that change to an accumulator. This is
+   * to (at least) handle the case where the user is moving three fingers, and
+   * then one of the fingers stops but the other two continue.
+   *
+   * This is very different than taking all of the recently moved touches and
+   * storing their centroid as `dx/dy`. For correctness, we must *accumulate
+   * changes* in the centroid of recently moved touches.
+   *
+   * There is also some nuance with how we handle multiple moved touches in a
+   * single event. With the way `ReactNativeEventEmitter` dispatches touches as
+   * individual events, multiple touches generate two 'move' events, each of
+   * them triggering `onResponderMove`. But with the way `PanResponder` works,
+   * all of the gesture inference is performed on the first dispatch, since it
+   * looks at all of the touches (even the ones for which there hasn't been a
+   * native dispatch yet). Therefore, `PanResponder` does not call
+   * `onResponderMove` passed the first dispatch. This diverges from the
+   * typical responder callback pattern (without using `PanResponder`), but
+   * avoids more dispatches than necessary.
+   */
+  _updateGestureStateOnMove(
+    gestureState: GestureState,
+    touchHistory: $PropertyType<PressEvent, 'touchHistory'>,
+  ) {
+    gestureState.numberActiveTouches = touchHistory.numberActiveTouches;
+    gestureState.moveX = currentCentroidXOfTouchesChangedAfter(
+      touchHistory,
+      gestureState._accountsForMovesUpTo,
+    );
+    gestureState.moveY = currentCentroidYOfTouchesChangedAfter(
+      touchHistory,
+      gestureState._accountsForMovesUpTo,
+    );
+    const movedAfter = gestureState._accountsForMovesUpTo;
+    const prevX = previousCentroidXOfTouchesChangedAfter(
+      touchHistory,
+      movedAfter,
+    );
+    const x = currentCentroidXOfTouchesChangedAfter(touchHistory, movedAfter);
+    const prevY = previousCentroidYOfTouchesChangedAfter(
+      touchHistory,
+      movedAfter,
+    );
+    const y = currentCentroidYOfTouchesChangedAfter(touchHistory, movedAfter);
+    const nextDX = gestureState.dx + (x - prevX);
+    const nextDY = gestureState.dy + (y - prevY);
+
+    // TODO: This must be filtered intelligently.
+    const dt =
+      touchHistory.mostRecentTimeStamp - gestureState._accountsForMovesUpTo;
+    gestureState.vx = (nextDX - gestureState.dx) / dt;
+    gestureState.vy = (nextDY - gestureState.dy) / dt;
+
+    gestureState.dx = nextDX;
+    gestureState.dy = nextDY;
+    gestureState._accountsForMovesUpTo = touchHistory.mostRecentTimeStamp;
+  },
+
+  /**
+   * @param {object} config Enhanced versions of all of the responder callbacks
+   * that provide not only the typical `ResponderSyntheticEvent`, but also the
+   * `PanResponder` gesture state.  Simply replace the word `Responder` with
+   * `PanResponder` in each of the typical `onResponder*` callbacks. For
+   * example, the `config` object would look like:
+   *
+   *  - `onMoveShouldSetPanResponder: (e, gestureState) => {...}`
+   *  - `onMoveShouldSetPanResponderCapture: (e, gestureState) => {...}`
+   *  - `onStartShouldSetPanResponder: (e, gestureState) => {...}`
+   *  - `onStartShouldSetPanResponderCapture: (e, gestureState) => {...}`
+   *  - `onPanResponderReject: (e, gestureState) => {...}`
+   *  - `onPanResponderGrant: (e, gestureState) => {...}`
+   *  - `onPanResponderStart: (e, gestureState) => {...}`
+   *  - `onPanResponderEnd: (e, gestureState) => {...}`
+   *  - `onPanResponderRelease: (e, gestureState) => {...}`
+   *  - `onPanResponderMove: (e, gestureState) => {...}`
+   *  - `onPanResponderTerminate: (e, gestureState) => {...}`
+   *  - `onPanResponderTerminationRequest: (e, gestureState) => {...}`
+   *  - `onShouldBlockNativeResponder: (e, gestureState) => {...}`
+   *
+   *  In general, for events that have capture equivalents, we update the
+   *  gestureState once in the capture phase and can use it in the bubble phase
+   *  as well.
+   *
+   *  Be careful with onStartShould* callbacks. They only reflect updated
+   *  `gestureState` for start/end events that bubble/capture to the Node.
+   *  Once the node is the responder, you can rely on every start/end event
+   *  being processed by the gesture and `gestureState` being updated
+   *  accordingly. (numberActiveTouches) may not be totally accurate unless you
+   *  are the responder.
+   */
+  create(
+    config: PanResponderConfig,
+  ): $TEMPORARY$object<{|
+    getInteractionHandle: () => ?number,
+    panHandlers: $TEMPORARY$object<{|
+      onMoveShouldSetResponder: (event: PressEvent) => boolean,
+      onMoveShouldSetResponderCapture: (event: PressEvent) => boolean,
+      onResponderEnd: (event: PressEvent) => void,
+      onResponderGrant: (event: PressEvent) => boolean,
+      onResponderMove: (event: PressEvent) => void,
+      onResponderReject: (event: PressEvent) => void,
+      onResponderRelease: (event: PressEvent) => void,
+      onResponderStart: (event: PressEvent) => void,
+      onResponderTerminate: (event: PressEvent) => void,
+      onResponderTerminationRequest: (event: PressEvent) => boolean,
+      onStartShouldSetResponder: (event: PressEvent) => boolean,
+      onStartShouldSetResponderCapture: (event: PressEvent) => boolean,
+    |}>,
+  |}> {
+    const interactionState = {
+      handle: (null: ?number),
+    };
+    const gestureState: GestureState = {
+      // Useful for debugging
+      stateID: Math.random(),
+      moveX: 0,
+      moveY: 0,
+      x0: 0,
+      y0: 0,
+      dx: 0,
+      dy: 0,
+      vx: 0,
+      vy: 0,
+      numberActiveTouches: 0,
+      _accountsForMovesUpTo: 0,
+    };
+    const panHandlers = {
+      onStartShouldSetResponder(event: PressEvent): boolean {
+        return config.onStartShouldSetPanResponder == null
+          ? false
+          : config.onStartShouldSetPanResponder(event, gestureState);
+      },
+      onMoveShouldSetResponder(event: PressEvent): boolean {
+        return config.onMoveShouldSetPanResponder == null
+          ? false
+          : config.onMoveShouldSetPanResponder(event, gestureState);
+      },
+      onStartShouldSetResponderCapture(event: PressEvent): boolean {
+        // TODO: Actually, we should reinitialize the state any time
+        // touches.length increases from 0 active to > 0 active.
+        if (event.nativeEvent.touches.length === 1) {
+          PanResponder._initializeGestureState(gestureState);
+        }
+        gestureState.numberActiveTouches =
+          event.touchHistory.numberActiveTouches;
+        return config.onStartShouldSetPanResponderCapture != null
+          ? config.onStartShouldSetPanResponderCapture(event, gestureState)
+          : false;
+      },
+
+      onMoveShouldSetResponderCapture(event: PressEvent): boolean {
+        const touchHistory = event.touchHistory;
+        // Responder system incorrectly dispatches should* to current responder
+        // Filter out any touch moves past the first one - we would have
+        // already processed multi-touch geometry during the first event.
+        if (
+          gestureState._accountsForMovesUpTo ===
+          touchHistory.mostRecentTimeStamp
+        ) {
+          return false;
+        }
+        PanResponder._updateGestureStateOnMove(gestureState, touchHistory);
+        return config.onMoveShouldSetPanResponderCapture
+          ? config.onMoveShouldSetPanResponderCapture(event, gestureState)
+          : false;
+      },
+
+      onResponderGrant(event: PressEvent): boolean {
+        if (!interactionState.handle) {
+          interactionState.handle = InteractionManager.createInteractionHandle();
+        }
+        gestureState.x0 = currentCentroidX(event.touchHistory);
+        gestureState.y0 = currentCentroidY(event.touchHistory);
+        gestureState.dx = 0;
+        gestureState.dy = 0;
+        if (config.onPanResponderGrant) {
+          config.onPanResponderGrant(event, gestureState);
+        }
+        // TODO: t7467124 investigate if this can be removed
+        return config.onShouldBlockNativeResponder == null
+          ? true
+          : config.onShouldBlockNativeResponder(event, gestureState);
+      },
+
+      onResponderReject(event: PressEvent): void {
+        clearInteractionHandle(
+          interactionState,
+          config.onPanResponderReject,
+          event,
+          gestureState,
+        );
+      },
+
+      onResponderRelease(event: PressEvent): void {
+        clearInteractionHandle(
+          interactionState,
+          config.onPanResponderRelease,
+          event,
+          gestureState,
+        );
+        PanResponder._initializeGestureState(gestureState);
+      },
+
+      onResponderStart(event: PressEvent): void {
+        const touchHistory = event.touchHistory;
+        gestureState.numberActiveTouches = touchHistory.numberActiveTouches;
+        if (config.onPanResponderStart) {
+          config.onPanResponderStart(event, gestureState);
+        }
+      },
+
+      onResponderMove(event: PressEvent): void {
+        const touchHistory = event.touchHistory;
+        // Guard against the dispatch of two touch moves when there are two
+        // simultaneously changed touches.
+        if (
+          gestureState._accountsForMovesUpTo ===
+          touchHistory.mostRecentTimeStamp
+        ) {
+          return;
+        }
+        // Filter out any touch moves past the first one - we would have
+        // already processed multi-touch geometry during the first event.
+        PanResponder._updateGestureStateOnMove(gestureState, touchHistory);
+        if (config.onPanResponderMove) {
+          config.onPanResponderMove(event, gestureState);
+        }
+      },
+
+      onResponderEnd(event: PressEvent): void {
+        const touchHistory = event.touchHistory;
+        gestureState.numberActiveTouches = touchHistory.numberActiveTouches;
+        clearInteractionHandle(
+          interactionState,
+          config.onPanResponderEnd,
+          event,
+          gestureState,
+        );
+      },
+
+      onResponderTerminate(event: PressEvent): void {
+        clearInteractionHandle(
+          interactionState,
+          config.onPanResponderTerminate,
+          event,
+          gestureState,
+        );
+        PanResponder._initializeGestureState(gestureState);
+      },
+
+      onResponderTerminationRequest(event: PressEvent): boolean {
+        return config.onPanResponderTerminationRequest == null
+          ? true
+          : config.onPanResponderTerminationRequest(event, gestureState);
+      },
+    };
+    return {
+      panHandlers,
+      getInteractionHandle(): ?number {
+        return interactionState.handle;
+      },
+    };
+  },
+};
+
+function clearInteractionHandle(
+  interactionState: {handle: ?number, ...},
+  callback: ?(ActiveCallback | PassiveCallback),
+  event: PressEvent,
+  gestureState: GestureState,
+) {
+  if (interactionState.handle) {
+    InteractionManager.clearInteractionHandle(interactionState.handle);
+    interactionState.handle = null;
+  }
+  if (callback) {
+    callback(event, gestureState);
+  }
+}
+
+export type PanResponderInstance = $Call<
+  $PropertyType<typeof PanResponder, 'create'>,
+  PanResponderConfig,
+>;
+
+module.exports = PanResponder;

node_modules/react-native/Libraries/Interaction/TaskQueue.js

@@ -0,0 +1,184 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow
+ */
+
+'use strict';
+
+const infoLog = require('../Utilities/infoLog');
+const invariant = require('invariant');
+
+type SimpleTask = {
+  name: string,
+  run: () => void,
+  ...
+};
+type PromiseTask = {
+  name: string,
+  gen: () => Promise<any>,
+  ...
+};
+export type Task = Function | SimpleTask | PromiseTask;
+
+const DEBUG: false = false;
+
+/**
+ * TaskQueue - A system for queueing and executing a mix of simple callbacks and
+ * trees of dependent tasks based on Promises. No tasks are executed unless
+ * `processNext` is called.
+ *
+ * `enqueue` takes a Task object with either a simple `run` callback, or a
+ * `gen` function that returns a `Promise` and puts it in the queue.  If a gen
+ * function is supplied, then the promise it returns will block execution of
+ * tasks already in the queue until it resolves. This can be used to make sure
+ * the first task is fully resolved (including asynchronous dependencies that
+ * also schedule more tasks via `enqueue`) before starting on the next task.
+ * The `onMoreTasks` constructor argument is used to inform the owner that an
+ * async task has resolved and that the queue should be processed again.
+ *
+ * Note: Tasks are only actually executed with explicit calls to `processNext`.
+ */
+class TaskQueue {
+  /**
+   * TaskQueue instances are self contained and independent, so multiple tasks
+   * of varying semantics and priority can operate together.
+   *
+   * `onMoreTasks` is invoked when `PromiseTask`s resolve if there are more
+   * tasks to process.
+   */
+  constructor({onMoreTasks}: {onMoreTasks: () => void, ...}) {
+    this._onMoreTasks = onMoreTasks;
+    this._queueStack = [{tasks: [], popable: false}];
+  }
+
+  /**
+   * Add a task to the queue.  It is recommended to name your tasks for easier
+   * async debugging. Tasks will not be executed until `processNext` is called
+   * explicitly.
+   */
+  enqueue(task: Task): void {
+    this._getCurrentQueue().push(task);
+  }
+
+  enqueueTasks(tasks: Array<Task>): void {
+    tasks.forEach(task => this.enqueue(task));
+  }
+
+  cancelTasks(tasksToCancel: Array<Task>): void {
+    // search through all tasks and remove them.
+    this._queueStack = this._queueStack
+      .map(queue => ({
+        ...queue,
+        tasks: queue.tasks.filter(task => tasksToCancel.indexOf(task) === -1),
+      }))
+      .filter((queue, idx) => queue.tasks.length > 0 || idx === 0);
+  }
+
+  /**
+   * Check to see if `processNext` should be called.
+   *
+   * @returns {boolean} Returns true if there are tasks that are ready to be
+   * processed with `processNext`, or returns false if there are no more tasks
+   * to be processed right now, although there may be tasks in the queue that
+   * are blocked by earlier `PromiseTask`s that haven't resolved yet.
+   * `onMoreTasks` will be called after each `PromiseTask` resolves if there are
+   * tasks ready to run at that point.
+   */
+  hasTasksToProcess(): boolean {
+    return this._getCurrentQueue().length > 0;
+  }
+
+  /**
+   * Executes the next task in the queue.
+   */
+  processNext(): void {
+    const queue = this._getCurrentQueue();
+    if (queue.length) {
+      const task = queue.shift();
+      try {
+        if (task.gen) {
+          DEBUG && infoLog('TaskQueue: genPromise for task ' + task.name);
+          this._genPromise((task: any)); // Rather than annoying tagged union
+        } else if (task.run) {
+          DEBUG && infoLog('TaskQueue: run task ' + task.name);
+          task.run();
+        } else {
+          invariant(
+            typeof task === 'function',
+            'Expected Function, SimpleTask, or PromiseTask, but got:\n' +
+              JSON.stringify(task, null, 2),
+          );
+          DEBUG && infoLog('TaskQueue: run anonymous task');
+          task();
+        }
+      } catch (e) {
+        e.message =
+          'TaskQueue: Error with task ' + (task.name || '') + ': ' + e.message;
+        throw e;
+      }
+    }
+  }
+
+  _queueStack: Array<{
+    tasks: Array<Task>,
+    popable: boolean,
+    ...
+  }>;
+  _onMoreTasks: () => void;
+
+  _getCurrentQueue(): Array<Task> {
+    const stackIdx = this._queueStack.length - 1;
+    const queue = this._queueStack[stackIdx];
+    if (
+      queue.popable &&
+      queue.tasks.length === 0 &&
+      this._queueStack.length > 1
+    ) {
+      this._queueStack.pop();
+      DEBUG &&
+        infoLog('TaskQueue: popped queue: ', {
+          stackIdx,
+          queueStackSize: this._queueStack.length,
+        });
+      return this._getCurrentQueue();
+    } else {
+      return queue.tasks;
+    }
+  }
+
+  _genPromise(task: PromiseTask) {
+    // Each async task pushes it's own queue onto the queue stack. This
+    // effectively defers execution of previously queued tasks until the promise
+    // resolves, at which point we allow the new queue to be popped, which
+    // happens once it is fully processed.
+    this._queueStack.push({tasks: [], popable: false});
+    const stackIdx = this._queueStack.length - 1;
+    DEBUG && infoLog('TaskQueue: push new queue: ', {stackIdx});
+    DEBUG && infoLog('TaskQueue: exec gen task ' + task.name);
+    task
+      .gen()
+      .then(() => {
+        DEBUG &&
+          infoLog('TaskQueue: onThen for gen task ' + task.name, {
+            stackIdx,
+            queueStackSize: this._queueStack.length,
+          });
+        this._queueStack[stackIdx].popable = true;
+        this.hasTasksToProcess() && this._onMoreTasks();
+      })
+      .catch(ex => {
+        ex.message = `TaskQueue: Error resolving Promise in task ${
+          task.name
+        }: ${ex.message}`;
+        throw ex;
+      })
+      .done();
+  }
+}
+
+module.exports = TaskQueue;

node_modules/react-native/Libraries/Interaction/TouchHistoryMath.js

@@ -0,0 +1,153 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+const TouchHistoryMath = {
+  /**
+   * This code is optimized and not intended to look beautiful. This allows
+   * computing of touch centroids that have moved after `touchesChangedAfter`
+   * timeStamp. You can compute the current centroid involving all touches
+   * moves after `touchesChangedAfter`, or you can compute the previous
+   * centroid of all touches that were moved after `touchesChangedAfter`.
+   *
+   * @param {TouchHistoryMath} touchHistory Standard Responder touch track
+   * data.
+   * @param {number} touchesChangedAfter timeStamp after which moved touches
+   * are considered "actively moving" - not just "active".
+   * @param {boolean} isXAxis Consider `x` dimension vs. `y` dimension.
+   * @param {boolean} ofCurrent Compute current centroid for actively moving
+   * touches vs. previous centroid of now actively moving touches.
+   * @return {number} value of centroid in specified dimension.
+   */
+  centroidDimension: function(
+    touchHistory,
+    touchesChangedAfter,
+    isXAxis,
+    ofCurrent,
+  ) {
+    const touchBank = touchHistory.touchBank;
+    let total = 0;
+    let count = 0;
+
+    const oneTouchData =
+      touchHistory.numberActiveTouches === 1
+        ? touchHistory.touchBank[touchHistory.indexOfSingleActiveTouch]
+        : null;
+
+    if (oneTouchData !== null) {
+      if (
+        oneTouchData.touchActive &&
+        oneTouchData.currentTimeStamp > touchesChangedAfter
+      ) {
+        total +=
+          ofCurrent && isXAxis
+            ? oneTouchData.currentPageX
+            : ofCurrent && !isXAxis
+            ? oneTouchData.currentPageY
+            : !ofCurrent && isXAxis
+            ? oneTouchData.previousPageX
+            : oneTouchData.previousPageY;
+        count = 1;
+      }
+    } else {
+      for (let i = 0; i < touchBank.length; i++) {
+        const touchTrack = touchBank[i];
+        if (
+          touchTrack !== null &&
+          touchTrack !== undefined &&
+          touchTrack.touchActive &&
+          touchTrack.currentTimeStamp >= touchesChangedAfter
+        ) {
+          let toAdd; // Yuck, program temporarily in invalid state.
+          if (ofCurrent && isXAxis) {
+            toAdd = touchTrack.currentPageX;
+          } else if (ofCurrent && !isXAxis) {
+            toAdd = touchTrack.currentPageY;
+          } else if (!ofCurrent && isXAxis) {
+            toAdd = touchTrack.previousPageX;
+          } else {
+            toAdd = touchTrack.previousPageY;
+          }
+          total += toAdd;
+          count++;
+        }
+      }
+    }
+    return count > 0 ? total / count : TouchHistoryMath.noCentroid;
+  },
+
+  currentCentroidXOfTouchesChangedAfter: function(
+    touchHistory,
+    touchesChangedAfter,
+  ) {
+    return TouchHistoryMath.centroidDimension(
+      touchHistory,
+      touchesChangedAfter,
+      true, // isXAxis
+      true, // ofCurrent
+    );
+  },
+
+  currentCentroidYOfTouchesChangedAfter: function(
+    touchHistory,
+    touchesChangedAfter,
+  ) {
+    return TouchHistoryMath.centroidDimension(
+      touchHistory,
+      touchesChangedAfter,
+      false, // isXAxis
+      true, // ofCurrent
+    );
+  },
+
+  previousCentroidXOfTouchesChangedAfter: function(
+    touchHistory,
+    touchesChangedAfter,
+  ) {
+    return TouchHistoryMath.centroidDimension(
+      touchHistory,
+      touchesChangedAfter,
+      true, // isXAxis
+      false, // ofCurrent
+    );
+  },
+
+  previousCentroidYOfTouchesChangedAfter: function(
+    touchHistory,
+    touchesChangedAfter,
+  ) {
+    return TouchHistoryMath.centroidDimension(
+      touchHistory,
+      touchesChangedAfter,
+      false, // isXAxis
+      false, // ofCurrent
+    );
+  },
+
+  currentCentroidX: function(touchHistory) {
+    return TouchHistoryMath.centroidDimension(
+      touchHistory,
+      0, // touchesChangedAfter
+      true, // isXAxis
+      true, // ofCurrent
+    );
+  },
+
+  currentCentroidY: function(touchHistory) {
+    return TouchHistoryMath.centroidDimension(
+      touchHistory,
+      0, // touchesChangedAfter
+      false, // isXAxis
+      true, // ofCurrent
+    );
+  },
+
+  noCentroid: -1,
+};
+
+module.exports = TouchHistoryMath;