@ionic/core/components/gesture-controller.js

/*!
 * (C) Ionic http://ionicframework.com - MIT License
 */
class GestureController {
  constructor() {
    this.gestureId = 0;
    this.requestedStart = new Map();
    this.disabledGestures = new Map();
    this.disabledScroll = new Set();
  }
  /**
   * Creates a gesture delegate based on the GestureConfig passed
   */
  createGesture(config) {
    return new GestureDelegate(this, this.newID(), config.name, config.priority || 0, !!config.disableScroll);
  }
  /**
   * Creates a blocker that will block any other gesture events from firing. Set in the ion-gesture component.
   */
  createBlocker(opts = {}) {
    return new BlockerDelegate(this, this.newID(), opts.disable, !!opts.disableScroll);
  }
  start(gestureName, id, priority) {
    if (!this.canStart(gestureName)) {
      this.requestedStart.delete(id);
      return false;
    }
    this.requestedStart.set(id, priority);
    return true;
  }
  capture(gestureName, id, priority) {
    if (!this.start(gestureName, id, priority)) {
      return false;
    }
    const requestedStart = this.requestedStart;
    let maxPriority = -10000;
    requestedStart.forEach(value => {
      maxPriority = Math.max(maxPriority, value);
    });
    if (maxPriority === priority) {
      this.capturedId = id;
      requestedStart.clear();
      const event = new CustomEvent('ionGestureCaptured', { detail: { gestureName } });
      document.dispatchEvent(event);
      return true;
    }
    requestedStart.delete(id);
    return false;
  }
  release(id) {
    this.requestedStart.delete(id);
    if (this.capturedId === id) {
      this.capturedId = undefined;
    }
  }
  disableGesture(gestureName, id) {
    let set = this.disabledGestures.get(gestureName);
    if (set === undefined) {
      set = new Set();
      this.disabledGestures.set(gestureName, set);
    }
    set.add(id);
  }
  enableGesture(gestureName, id) {
    const set = this.disabledGestures.get(gestureName);
    if (set !== undefined) {
      set.delete(id);
    }
  }
  disableScroll(id) {
    this.disabledScroll.add(id);
    if (this.disabledScroll.size === 1) {
      document.body.classList.add(BACKDROP_NO_SCROLL);
    }
  }
  enableScroll(id) {
    this.disabledScroll.delete(id);
    if (this.disabledScroll.size === 0) {
      document.body.classList.remove(BACKDROP_NO_SCROLL);
    }
  }
  canStart(gestureName) {
    if (this.capturedId !== undefined) {
      // a gesture already captured
      return false;
    }
    if (this.isDisabled(gestureName)) {
      return false;
    }
    return true;
  }
  isCaptured() {
    return this.capturedId !== undefined;
  }
  isScrollDisabled() {
    return this.disabledScroll.size > 0;
  }
  isDisabled(gestureName) {
    const disabled = this.disabledGestures.get(gestureName);
    if (disabled && disabled.size > 0) {
      return true;
    }
    return false;
  }
  newID() {
    this.gestureId++;
    return this.gestureId;
  }
}
class GestureDelegate {
  constructor(ctrl, id, name, priority, disableScroll) {
    this.id = id;
    this.name = name;
    this.disableScroll = disableScroll;
    this.priority = priority * 1000000 + id;
    this.ctrl = ctrl;
  }
  canStart() {
    if (!this.ctrl) {
      return false;
    }
    return this.ctrl.canStart(this.name);
  }
  start() {
    if (!this.ctrl) {
      return false;
    }
    return this.ctrl.start(this.name, this.id, this.priority);
  }
  capture() {
    if (!this.ctrl) {
      return false;
    }
    const captured = this.ctrl.capture(this.name, this.id, this.priority);
    if (captured && this.disableScroll) {
      this.ctrl.disableScroll(this.id);
    }
    return captured;
  }
  release() {
    if (this.ctrl) {
      this.ctrl.release(this.id);
      if (this.disableScroll) {
        this.ctrl.enableScroll(this.id);
      }
    }
  }
  destroy() {
    this.release();
    this.ctrl = undefined;
  }
}
class BlockerDelegate {
  constructor(ctrl, id, disable, disableScroll) {
    this.id = id;
    this.disable = disable;
    this.disableScroll = disableScroll;
    this.ctrl = ctrl;
  }
  block() {
    if (!this.ctrl) {
      return;
    }
    if (this.disable) {
      for (const gesture of this.disable) {
        this.ctrl.disableGesture(gesture, this.id);
      }
    }
    if (this.disableScroll) {
      this.ctrl.disableScroll(this.id);
    }
  }
  unblock() {
    if (!this.ctrl) {
      return;
    }
    if (this.disable) {
      for (const gesture of this.disable) {
        this.ctrl.enableGesture(gesture, this.id);
      }
    }
    if (this.disableScroll) {
      this.ctrl.enableScroll(this.id);
    }
  }
  destroy() {
    this.unblock();
    this.ctrl = undefined;
  }
}
const BACKDROP_NO_SCROLL = 'backdrop-no-scroll';
const GESTURE_CONTROLLER = new GestureController();

export { GESTURE_CONTROLLER as G };