130 lines
3.5 KiB
JavaScript
130 lines
3.5 KiB
JavaScript
////////////////////////////////////////////////////////////////////////////
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//
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// Copyright 2016 Realm Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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////////////////////////////////////////////////////////////////////////////
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'use strict';
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import { keys } from './constants';
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import { getterForProperty, setterForProperty } from './util';
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let mutationListeners = {};
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export default class Collection {
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constructor() {
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throw new TypeError('Illegal constructor');
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}
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}
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export function addMutationListener(realmId, callback) {
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let listeners = mutationListeners[realmId] || (mutationListeners[realmId] = new Set());
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listeners.add(callback);
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}
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export function removeMutationListener(realmId, callback) {
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let listeners = mutationListeners[realmId];
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if (listeners) {
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listeners.delete(callback);
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}
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}
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export function clearMutationListeners() {
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mutationListeners = {};
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}
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export function fireMutationListeners(realmId) {
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let listeners = mutationListeners[realmId];
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if (listeners) {
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listeners.forEach((cb) => cb());
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}
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}
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export function createCollection(prototype, realmId, info, _mutable) {
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let collection = Object.create(prototype);
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let size;
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Object.defineProperties(collection, {
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'length': {
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get: getterForProperty('length'),
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},
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'-1': {
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value: undefined,
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},
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});
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let resize = function(length) {
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if (length == null) {
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length = collection.length;
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}
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if (length == size) {
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return; // Nothing has changed.
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}
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if (size == null) {
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size = 0; // This is first pass.
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}
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let props = {};
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if (length > size) {
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for (let i = size; i < length; i++) {
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props[i] = {
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get: getterForProperty(i),
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set: setterForProperty(i),
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enumerable: true,
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configurable: true,
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};
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}
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}
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else if (length < size) {
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for (let i = size; i >= length; i--) {
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delete collection[i];
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}
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}
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// Helpfully throw an exception on attempts to set to one past the last index.
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props[length] = {
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get: getterForProperty(length),
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set: setterForProperty(length),
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configurable: true,
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};
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Object.defineProperties(collection, props);
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size = length;
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};
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collection[keys.realm] = realmId;
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collection[keys.id] = info.id;
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collection[keys.type] = info.type;
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resize(info.size);
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addMutationListener(realmId, function listener() {
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try {
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resize();
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} catch (e) {
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// If the error indicates the collection was deleted, then remove this listener.
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if (e.message.indexOf('Access to invalidated') == 0) {
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removeMutationListener(realmId, listener);
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} else {
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throw e;
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}
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}
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});
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return collection;
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}
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