react-native-firebase-for-netmera/dist/modules/database/transaction.js

.

/**
 * 
 * Database Transaction representation wrapper
 */
import { getAppEventName, SharedEventEmitter } from '../../utils/events';
import { getLogger } from '../../utils/log';
import { getNativeModule } from '../../utils/native';
let transactionId = 0;
/**
 * Uses the push id generator to create a transaction id
 * @returns {number}
 * @private
 */

const generateTransactionId = () => transactionId++;
/**
 * @class TransactionHandler
 */


export default class TransactionHandler {
  constructor(database) {
    this._transactions = {};
    this._database = database;
    SharedEventEmitter.addListener(getAppEventName(this._database, 'database_transaction_event'), this._handleTransactionEvent.bind(this));
  }
  /**
   * Add a new transaction and start it natively.
   * @param reference
   * @param transactionUpdater
   * @param onComplete
   * @param applyLocally
   */


  add(reference, transactionUpdater, onComplete, applyLocally = false) {
    const id = generateTransactionId();
    this._transactions[id] = {
      id,
      reference,
      transactionUpdater,
      onComplete,
      applyLocally,
      completed: false,
      started: true
    };
    getNativeModule(this._database).transactionStart(reference.path, id, applyLocally);
  }
  /**
   *  INTERNALS
   */

  /**
   *
   * @param event
   * @returns {*}
   * @private
   */


  _handleTransactionEvent(event = {}) {
    switch (event.type) {
      case 'update':
        return this._handleUpdate(event);

      case 'error':
        return this._handleError(event);

      case 'complete':
        return this._handleComplete(event);

      default:
        getLogger(this._database).warn(`Unknown transaction event type: '${event.type}'`, event);
        return undefined;
    }
  }
  /**
   *
   * @param event
   * @private
   */


  _handleUpdate(event = {}) {
    let newValue;
    const {
      id,
      value
    } = event;

    try {
      const transaction = this._transactions[id];
      if (!transaction) return;
      newValue = transaction.transactionUpdater(value);
    } finally {
      let abort = false;

      if (newValue === undefined) {
        abort = true;
      }

      getNativeModule(this._database).transactionTryCommit(id, {
        value: newValue,
        abort
      });
    }
  }
  /**
   *
   * @param event
   * @private
   */


  _handleError(event = {}) {
    const transaction = this._transactions[event.id];

    if (transaction && !transaction.completed) {
      transaction.completed = true;

      try {
        transaction.onComplete(event.error, false, null);
      } finally {
        setImmediate(() => {
          delete this._transactions[event.id];
        });
      }
    }
  }
  /**
   *
   * @param event
   * @private
   */


  _handleComplete(event = {}) {
    const transaction = this._transactions[event.id];

    if (transaction && !transaction.completed) {
      transaction.completed = true;

      try {
        transaction.onComplete(null, event.committed, Object.assign({}, event.snapshot));
      } finally {
        setImmediate(() => {
          delete this._transactions[event.id];
        });
      }
    }
  }

}