react/packages/react-native-renderer/src/ReactNativeBridgeEventPlugin.js

/**
 * 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
 */

import type {AnyNativeEvent} from 'legacy-events/PluginModuleType';
import type {EventSystemFlags} from 'legacy-events/EventSystemFlags';
import type {TopLevelType} from 'legacy-events/TopLevelEventTypes';
import SyntheticEvent from 'legacy-events/SyntheticEvent';
import invariant from 'shared/invariant';

// Module provided by RN:
import {ReactNativeViewConfigRegistry} from 'react-native/Libraries/ReactPrivate/ReactNativePrivateInterface';
import accumulateInto from 'legacy-events/accumulateInto';
import getListener from 'legacy-events/getListener';
import forEachAccumulated from 'legacy-events/forEachAccumulated';
import {HostComponent} from 'react-reconciler/src/ReactWorkTags';

const {
  customBubblingEventTypes,
  customDirectEventTypes,
} = ReactNativeViewConfigRegistry;

// Start of inline: the below functions were inlined from
// EventPropagator.js, as they deviated from ReactDOM's newer
// implementations.
function listenerAtPhase(inst, event, propagationPhase: PropagationPhases) {
  const registrationName =
    event.dispatchConfig.phasedRegistrationNames[propagationPhase];
  return getListener(inst, registrationName);
}

function accumulateDirectionalDispatches(inst, phase, event) {
  if (__DEV__) {
    if (!inst) {
      console.error('Dispatching inst must not be null');
    }
  }
  const listener = listenerAtPhase(inst, event, phase);
  if (listener) {
    event._dispatchListeners = accumulateInto(
      event._dispatchListeners,
      listener,
    );
    event._dispatchInstances = accumulateInto(event._dispatchInstances, inst);
  }
}

function getParent(inst) {
  do {
    inst = inst.return;
    // TODO: If this is a HostRoot we might want to bail out.
    // That is depending on if we want nested subtrees (layers) to bubble
    // events to their parent. We could also go through parentNode on the
    // host node but that wouldn't work for React Native and doesn't let us
    // do the portal feature.
  } while (inst && inst.tag !== HostComponent);
  if (inst) {
    return inst;
  }
  return null;
}

/**
 * Simulates the traversal of a two-phase, capture/bubble event dispatch.
 */
export function traverseTwoPhase(inst: Object, fn: Function, arg: Function) {
  const path = [];
  while (inst) {
    path.push(inst);
    inst = getParent(inst);
  }
  let i;
  for (i = path.length; i-- > 0; ) {
    fn(path[i], 'captured', arg);
  }
  for (i = 0; i < path.length; i++) {
    fn(path[i], 'bubbled', arg);
  }
}

function accumulateTwoPhaseDispatchesSingle(event) {
  if (event && event.dispatchConfig.phasedRegistrationNames) {
    traverseTwoPhase(event._targetInst, accumulateDirectionalDispatches, event);
  }
}

function accumulateTwoPhaseDispatches(events) {
  forEachAccumulated(events, accumulateTwoPhaseDispatchesSingle);
}

/**
 * Accumulates without regard to direction, does not look for phased
 * registration names. Same as `accumulateDirectDispatchesSingle` but without
 * requiring that the `dispatchMarker` be the same as the dispatched ID.
 */
function accumulateDispatches(
  inst: Object,
  ignoredDirection: ?boolean,
  event: Object,
): void {
  if (inst && event && event.dispatchConfig.registrationName) {
    const registrationName = event.dispatchConfig.registrationName;
    const listener = getListener(inst, registrationName);
    if (listener) {
      event._dispatchListeners = accumulateInto(
        event._dispatchListeners,
        listener,
      );
      event._dispatchInstances = accumulateInto(event._dispatchInstances, inst);
    }
  }
}

/**
 * Accumulates dispatches on an `SyntheticEvent`, but only for the
 * `dispatchMarker`.
 * @param {SyntheticEvent} event
 */
function accumulateDirectDispatchesSingle(event: Object) {
  if (event && event.dispatchConfig.registrationName) {
    accumulateDispatches(event._targetInst, null, event);
  }
}

function accumulateDirectDispatches(events: ?(Array<Object> | Object)) {
  forEachAccumulated(events, accumulateDirectDispatchesSingle);
}

// End of inline
type PropagationPhases = 'bubbled' | 'captured';

const ReactNativeBridgeEventPlugin = {
  eventTypes: {},

  extractEvents: function(
    topLevelType: TopLevelType,
    targetInst: null | Object,
    nativeEvent: AnyNativeEvent,
    nativeEventTarget: null | Object,
    eventSystemFlags: EventSystemFlags,
  ): ?Object {
    if (targetInst == null) {
      // Probably a node belonging to another renderer's tree.
      return null;
    }
    const bubbleDispatchConfig = customBubblingEventTypes[topLevelType];
    const directDispatchConfig = customDirectEventTypes[topLevelType];
    invariant(
      bubbleDispatchConfig || directDispatchConfig,
      'Unsupported top level event type "%s" dispatched',
      topLevelType,
    );
    const event = SyntheticEvent.getPooled(
      bubbleDispatchConfig || directDispatchConfig,
      targetInst,
      nativeEvent,
      nativeEventTarget,
    );
    if (bubbleDispatchConfig) {
      accumulateTwoPhaseDispatches(event);
    } else if (directDispatchConfig) {
      accumulateDirectDispatches(event);
    } else {
      return null;
    }
    return event;
  },
};

export default ReactNativeBridgeEventPlugin;