148 lines
3.3 KiB
JavaScript
148 lines
3.3 KiB
JavaScript
/**
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* @flow
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* Database Transaction representation wrapper
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*/
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import { getAppEventName, SharedEventEmitter } from '../../utils/events';
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import { getLogger } from '../../utils/log';
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import type Database from './';
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let transactionId = 0;
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/**
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* @class TransactionHandler
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*/
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export default class TransactionHandler {
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_database: Database;
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_transactionListener: Function;
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_transactions: { [string]: Object }
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constructor(database: Database) {
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this._transactions = {};
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this._database = database;
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this._transactionListener = SharedEventEmitter.addListener(
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getAppEventName(this._database, 'database_transaction_event'),
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this._handleTransactionEvent.bind(this),
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);
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}
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/**
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* Add a new transaction and start it natively.
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* @param reference
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* @param transactionUpdater
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* @param onComplete
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* @param applyLocally
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*/
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add(reference: Object, transactionUpdater: Function, onComplete?: Function, applyLocally?: boolean = false) {
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const id = this._generateTransactionId();
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this._transactions[id] = {
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id,
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reference,
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transactionUpdater,
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onComplete,
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applyLocally,
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completed: false,
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started: true,
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};
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this._database._native.transactionStart(reference.path, id, applyLocally);
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}
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/**
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* INTERNALS
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*/
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/**
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* Uses the push id generator to create a transaction id
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* @returns {string}
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* @private
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*/
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_generateTransactionId(): string {
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return transactionId++;
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}
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/**
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*
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* @param event
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* @returns {*}
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* @private
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*/
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_handleTransactionEvent(event: Object = {}) {
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switch (event.type) {
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case 'update':
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return this._handleUpdate(event);
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case 'error':
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return this._handleError(event);
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case 'complete':
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return this._handleComplete(event);
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default:
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getLogger(this._database).warn(`Unknown transaction event type: '${event.type}'`, event);
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return undefined;
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}
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}
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/**
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*
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* @param event
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* @private
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*/
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_handleUpdate(event: Object = {}) {
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let newValue;
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const { id, value } = event;
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try {
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const transaction = this._transactions[id];
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if (!transaction) return;
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newValue = transaction.transactionUpdater(value);
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} finally {
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let abort = false;
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if (newValue === undefined) {
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abort = true;
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}
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this._database._native.transactionTryCommit(id, { value: newValue, abort });
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}
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}
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/**
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*
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* @param event
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* @private
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*/
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_handleError(event: Object = {}) {
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const transaction = this._transactions[event.id];
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if (transaction && !transaction.completed) {
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transaction.completed = true;
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try {
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transaction.onComplete(new Error(event.error.message, event.error.code), null);
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} finally {
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setImmediate(() => {
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delete this._transactions[event.id];
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});
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}
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}
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}
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/**
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*
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* @param event
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* @private
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*/
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_handleComplete(event: Object = {}) {
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const transaction = this._transactions[event.id];
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if (transaction && !transaction.completed) {
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transaction.completed = true;
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try {
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transaction.onComplete(null, event.committed, Object.assign({}, event.snapshot));
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} finally {
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setImmediate(() => {
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delete this._transactions[event.id];
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});
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}
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}
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}
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}
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