309 lines
8.6 KiB
JavaScript
309 lines
8.6 KiB
JavaScript
/**
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* this method uses indexeddb to store the messages
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* There is currently no observerAPI for idb
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* @link https://github.com/w3c/IndexedDB/issues/51
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*/
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import { sleep, randomInt, randomToken, microSeconds as micro, isNode } from '../util.js';
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export var microSeconds = micro;
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import { ObliviousSet } from 'oblivious-set';
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import { fillOptionsWithDefaults } from '../options';
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var DB_PREFIX = 'pubkey.broadcast-channel-0-';
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var OBJECT_STORE_ID = 'messages';
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export var type = 'idb';
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export function getIdb() {
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if (typeof indexedDB !== 'undefined') return indexedDB;
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if (typeof window !== 'undefined') {
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if (typeof window.mozIndexedDB !== 'undefined') return window.mozIndexedDB;
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if (typeof window.webkitIndexedDB !== 'undefined') return window.webkitIndexedDB;
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if (typeof window.msIndexedDB !== 'undefined') return window.msIndexedDB;
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}
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return false;
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}
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export function createDatabase(channelName) {
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var IndexedDB = getIdb(); // create table
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var dbName = DB_PREFIX + channelName;
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var openRequest = IndexedDB.open(dbName, 1);
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openRequest.onupgradeneeded = function (ev) {
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var db = ev.target.result;
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db.createObjectStore(OBJECT_STORE_ID, {
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keyPath: 'id',
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autoIncrement: true
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});
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};
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var dbPromise = new Promise(function (res, rej) {
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openRequest.onerror = function (ev) {
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return rej(ev);
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};
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openRequest.onsuccess = function () {
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res(openRequest.result);
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};
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});
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return dbPromise;
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}
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/**
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* writes the new message to the database
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* so other readers can find it
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*/
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export function writeMessage(db, readerUuid, messageJson) {
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var time = new Date().getTime();
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var writeObject = {
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uuid: readerUuid,
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time: time,
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data: messageJson
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};
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var transaction = db.transaction([OBJECT_STORE_ID], 'readwrite');
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return new Promise(function (res, rej) {
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transaction.oncomplete = function () {
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return res();
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};
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transaction.onerror = function (ev) {
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return rej(ev);
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};
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var objectStore = transaction.objectStore(OBJECT_STORE_ID);
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objectStore.add(writeObject);
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});
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}
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export function getAllMessages(db) {
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var objectStore = db.transaction(OBJECT_STORE_ID).objectStore(OBJECT_STORE_ID);
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var ret = [];
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return new Promise(function (res) {
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objectStore.openCursor().onsuccess = function (ev) {
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var cursor = ev.target.result;
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if (cursor) {
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ret.push(cursor.value); //alert("Name for SSN " + cursor.key + " is " + cursor.value.name);
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cursor["continue"]();
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} else {
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res(ret);
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}
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};
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});
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}
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export function getMessagesHigherThan(db, lastCursorId) {
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var objectStore = db.transaction(OBJECT_STORE_ID).objectStore(OBJECT_STORE_ID);
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var ret = [];
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function openCursor() {
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// Occasionally Safari will fail on IDBKeyRange.bound, this
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// catches that error, having it open the cursor to the first
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// item. When it gets data it will advance to the desired key.
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try {
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var keyRangeValue = IDBKeyRange.bound(lastCursorId + 1, Infinity);
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return objectStore.openCursor(keyRangeValue);
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} catch (e) {
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return objectStore.openCursor();
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}
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}
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return new Promise(function (res) {
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openCursor().onsuccess = function (ev) {
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var cursor = ev.target.result;
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if (cursor) {
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if (cursor.value.id < lastCursorId + 1) {
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cursor["continue"](lastCursorId + 1);
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} else {
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ret.push(cursor.value);
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cursor["continue"]();
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}
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} else {
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res(ret);
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}
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};
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});
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}
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export function removeMessageById(db, id) {
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var request = db.transaction([OBJECT_STORE_ID], 'readwrite').objectStore(OBJECT_STORE_ID)["delete"](id);
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return new Promise(function (res) {
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request.onsuccess = function () {
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return res();
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};
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});
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}
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export function getOldMessages(db, ttl) {
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var olderThen = new Date().getTime() - ttl;
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var objectStore = db.transaction(OBJECT_STORE_ID).objectStore(OBJECT_STORE_ID);
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var ret = [];
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return new Promise(function (res) {
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objectStore.openCursor().onsuccess = function (ev) {
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var cursor = ev.target.result;
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if (cursor) {
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var msgObk = cursor.value;
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if (msgObk.time < olderThen) {
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ret.push(msgObk); //alert("Name for SSN " + cursor.key + " is " + cursor.value.name);
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cursor["continue"]();
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} else {
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// no more old messages,
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res(ret);
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return;
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}
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} else {
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res(ret);
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}
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};
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});
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}
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export function cleanOldMessages(db, ttl) {
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return getOldMessages(db, ttl).then(function (tooOld) {
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return Promise.all(tooOld.map(function (msgObj) {
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return removeMessageById(db, msgObj.id);
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}));
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});
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}
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export function create(channelName, options) {
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options = fillOptionsWithDefaults(options);
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return createDatabase(channelName).then(function (db) {
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var state = {
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closed: false,
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lastCursorId: 0,
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channelName: channelName,
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options: options,
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uuid: randomToken(),
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/**
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* emittedMessagesIds
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* contains all messages that have been emitted before
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* @type {ObliviousSet}
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*/
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eMIs: new ObliviousSet(options.idb.ttl * 2),
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// ensures we do not read messages in parrallel
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writeBlockPromise: Promise.resolve(),
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messagesCallback: null,
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readQueuePromises: [],
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db: db
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};
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/**
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* Handle abrupt closes that do not originate from db.close().
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* This could happen, for example, if the underlying storage is
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* removed or if the user clears the database in the browser's
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* history preferences.
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*/
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db.onclose = function () {
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state.closed = true;
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if (options.idb.onclose) options.idb.onclose();
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};
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/**
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* if service-workers are used,
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* we have no 'storage'-event if they post a message,
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* therefore we also have to set an interval
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*/
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_readLoop(state);
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return state;
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});
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}
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function _readLoop(state) {
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if (state.closed) return;
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readNewMessages(state).then(function () {
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return sleep(state.options.idb.fallbackInterval);
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}).then(function () {
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return _readLoop(state);
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});
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}
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function _filterMessage(msgObj, state) {
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if (msgObj.uuid === state.uuid) return false; // send by own
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if (state.eMIs.has(msgObj.id)) return false; // already emitted
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if (msgObj.data.time < state.messagesCallbackTime) return false; // older then onMessageCallback
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return true;
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}
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/**
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* reads all new messages from the database and emits them
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*/
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function readNewMessages(state) {
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// channel already closed
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if (state.closed) return Promise.resolve(); // if no one is listening, we do not need to scan for new messages
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if (!state.messagesCallback) return Promise.resolve();
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return getMessagesHigherThan(state.db, state.lastCursorId).then(function (newerMessages) {
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var useMessages = newerMessages
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/**
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* there is a bug in iOS where the msgObj can be undefined some times
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* so we filter them out
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* @link https://github.com/pubkey/broadcast-channel/issues/19
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*/
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.filter(function (msgObj) {
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return !!msgObj;
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}).map(function (msgObj) {
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if (msgObj.id > state.lastCursorId) {
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state.lastCursorId = msgObj.id;
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}
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return msgObj;
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}).filter(function (msgObj) {
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return _filterMessage(msgObj, state);
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}).sort(function (msgObjA, msgObjB) {
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return msgObjA.time - msgObjB.time;
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}); // sort by time
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useMessages.forEach(function (msgObj) {
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if (state.messagesCallback) {
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state.eMIs.add(msgObj.id);
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state.messagesCallback(msgObj.data);
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}
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});
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return Promise.resolve();
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});
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}
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export function close(channelState) {
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channelState.closed = true;
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channelState.db.close();
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}
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export function postMessage(channelState, messageJson) {
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channelState.writeBlockPromise = channelState.writeBlockPromise.then(function () {
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return writeMessage(channelState.db, channelState.uuid, messageJson);
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}).then(function () {
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if (randomInt(0, 10) === 0) {
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/* await (do not await) */
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cleanOldMessages(channelState.db, channelState.options.idb.ttl);
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}
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});
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return channelState.writeBlockPromise;
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}
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export function onMessage(channelState, fn, time) {
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channelState.messagesCallbackTime = time;
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channelState.messagesCallback = fn;
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readNewMessages(channelState);
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}
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export function canBeUsed() {
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if (isNode) return false;
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var idb = getIdb();
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if (!idb) return false;
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return true;
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}
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export function averageResponseTime(options) {
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return options.idb.fallbackInterval * 2;
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}
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export default {
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create: create,
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close: close,
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onMessage: onMessage,
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postMessage: postMessage,
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canBeUsed: canBeUsed,
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type: type,
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averageResponseTime: averageResponseTime,
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microSeconds: microSeconds
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}; |