4.0.0 Beta 1

src/settings/providers.js

@@ -0,0 +1,301 @@
+'use strict';
+
+// ============================================================================
+// Settings Providers
+// ============================================================================
+
+import {EventEmitter} from 'utilities/events';
+import {has} from 'utilities/object';
+
+
+// ============================================================================
+// SettingsProvider
+// ============================================================================
+
+/**
+ * Base class for providers for the settings system. A provider is in charge
+ * of reading and writing values from storage as well as sending events to
+ * the {@link SettingsManager} when a value is changed remotely.
+ *
+ * @extends EventEmitter
+ */
+export class SettingsProvider extends EventEmitter {
+	/**
+	 * Create a new SettingsProvider
+	 * @param {SettingsManager} manager - The manager that owns this provider.
+	 */
+	constructor(manager) {
+		super();
+
+		this.manager = manager;
+		this.disabled = false;
+	}
+
+	awaitReady() {
+		if ( this.ready )
+			return Promise.resolve();
+
+		return Promise.reject(new Error('Not Implemented'));
+	}
+
+	get(key, default_value) { throw new Error('Not Implemented') } // eslint-disable-line class-methods-use-this, no-unused-vars
+	set(key, value) { throw new Error('Not Implemented') } // eslint-disable-line class-methods-use-this, no-unused-vars
+	delete(key) { throw new Error('Not Implemented') } // eslint-disable-line class-methods-use-this, no-unused-vars
+	clear() { throw new Error('Not Implemented') } // eslint-disable-line class-methods-use-this
+
+	has(key) { throw new Error('Not Implemented') } // eslint-disable-line class-methods-use-this, no-unused-vars
+
+	keys() { throw new Error('Not Implemented') } // eslint-disable-line class-methods-use-this
+	entries() { throw new Error('Not Implemented') } // eslint-disable-line class-methods-use-this
+	get size() { throw new Error('Not Implemented') } // eslint-disable-line class-methods-use-this
+}
+
+
+// ============================================================================
+// LocalStorage
+// ============================================================================
+
+export class LocalStorageProvider extends SettingsProvider {
+	constructor(manager, prefix) {
+		super(manager);
+		this.prefix = prefix = prefix == null ? 'FFZ:setting:' : prefix;
+
+		const cache = this._cached = new Map,
+			len = prefix.length;
+
+		for(const key in localStorage)
+			if ( has(localStorage, key) && key.startsWith(prefix) ) {
+				const val = localStorage.getItem(key);
+				try {
+					cache.set(key.slice(len), JSON.parse(val));
+				} catch(err) {
+					this.manager.log.warn(`unable to parse value for ${key}`, val);
+				}
+			}
+
+		this.ready = true;
+
+		this._boundHandleStorage = this.handleStorage.bind(this);
+		window.addEventListener('storage', this._boundHandleStorage);
+	}
+
+	destroy() {
+		this.disable();
+		this._cached.clear();
+	}
+
+	disable() {
+		this.disabled = true;
+
+		if ( this._boundHandleStorage ) {
+			window.removeEventListener('storage', this._boundHandleStorage);
+			this._boundHandleStorage = null;
+		}
+	}
+
+
+	handleStorage(event) {
+		if ( this.disabled )
+			return;
+
+		this.manager.log.debug('storage event', event);
+		if ( event.storageArea !== localStorage )
+			return;
+
+		if ( event.key.startsWith(this.prefix) ) {
+			// If value is null, the key was deleted.
+			const key = event.key.slice(this.prefix.length);
+			let val = event.newValue;
+
+			if ( val === null ) {
+				this._cached.delete(key);
+				this.emit('changed', key, undefined, true);
+
+			} else {
+				val = JSON.parse(val);
+				this._cached.set(key, val);
+				this.emit('changed', key, val, false);
+			}
+		}
+	}
+
+
+	get(key, default_value) {
+		return this._cached.has(key) ?
+			this._cached.get(key) :
+			default_value;
+	}
+
+	set(key, value) {
+		this._cached.set(key, value);
+		localStorage.setItem(this.prefix + key, JSON.stringify(value));
+	}
+
+	delete(key) {
+		this._cached.delete(key);
+		localStorage.removeItem(this.prefix + key);
+	}
+
+	has(key) {
+		return this._cached.has(key);
+	}
+
+	keys() {
+		return this._cached.keys();
+	}
+
+	clear() {
+		for(const key of this._cached.keys())
+			localStorage.removeItem(this.prefix + key);
+
+		this._cached.clear();
+	}
+
+	entries() {
+		return this._cached.entries();
+	}
+
+	get size() {
+		return this._cached.size;
+	}
+}
+
+
+export class CloudStorageProvider extends SettingsProvider {
+	constructor(manager) {
+		super(manager);
+
+		this._cached = new Map;
+		this.ready = false;
+		this._ready_wait = null;
+
+		this._boundHandleStorage = this.handleStorage.bind(this);
+		window.addEventListener('message', this._boundHandleStorage);
+		this._send('get_all');
+	}
+
+	destroy() {
+		this.disable();
+		this._cached.clear();
+	}
+
+	disable() {
+		this.disabled = true;
+
+		if ( this._boundHandleStorage ) {
+			window.removeEventListener('message', this._boundHandleStorage)
+			this._boundHandleStorage = null;
+		}
+	}
+
+
+	awaitReady() {
+		if ( this.ready )
+			return Promise.resolve();
+
+		return new Promise((resolve, reject) => {
+			const waiters = this._ready_wait = this._ready_wait || [];
+			waiters.push([resolve, reject]);
+		})
+	}
+
+
+	// ========================================================================
+	// Communication
+	// ========================================================================
+
+	handleStorage(event) {
+		if ( event.source !== window || ! event.data || ! event.data.ffz )
+			return;
+
+		const cmd = event.data.cmd,
+			data = event.data.data;
+
+		if ( cmd === 'all_values' ) {
+			const old_keys = new Set(this._cached.keys());
+
+			for(const key in data)
+				if ( has(data, key) ) {
+					const val = data[key];
+					old_keys.delete(key);
+					this._cached.set(key, val);
+					if ( this.ready )
+						this.emit('changed', key, val);
+				}
+
+			for(const key of old_keys) {
+				this._cached.delete(key);
+				if ( this.ready )
+					this.emit('changed', key, undefined, true);
+			}
+
+			this.ready = true;
+			if ( this._ready_wait ) {
+				for(const resolve of this._ready_wait)
+					resolve();
+				this._ready_wait = null;
+			}
+
+		} else if ( cmd === 'changed' ) {
+			this._cached.set(data.key, data.value);
+			this.emit('changed', data.key, data.value);
+
+		} else if ( cmd === 'deleted' ) {
+			this._cached.delete(data);
+			this.emit('changed', data, undefined, true);
+
+		} else {
+			this.manager.log.info('unknown storage event', event);
+		}
+	}
+
+	_send(cmd, data) { // eslint-disable-line class-methods-use-this
+		window.postMessage({
+			ffz: true,
+			cmd,
+			data
+		}, location.origin);
+	}
+
+
+	// ========================================================================
+	// Data Access
+	// ========================================================================
+
+	get(key, default_value) {
+		return this._cached.has(key) ?
+			this._cached.get(key) :
+			default_value;
+	}
+
+	set(key, value) {
+		this._cached.set(key, value);
+		this._send('set', {key, value});
+	}
+
+	delete(key) {
+		this._cached.delete(key);
+		this._send('delete', key);
+	}
+
+	has(key) {
+		return this._cached.has(key);
+	}
+
+	keys() {
+		return this._cached.keys();
+	}
+
+	clear() {
+		this._cached.clear();
+		this._send('clear');
+	}
+
+	entries() {
+		return this._cached.entries();
+	}
+
+	get size() {
+		return this._cached.size;
+	}
+}