1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/addon-sdk/source/lib/sdk/simple-storage.js Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,296 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +"use strict";
1.9 +
1.10 +module.metadata = {
1.11 + "stability": "stable"
1.12 +};
1.13 +
1.14 +const { Cc, Ci, Cu } = require("chrome");
1.15 +const file = require("./io/file");
1.16 +const prefs = require("./preferences/service");
1.17 +const jpSelf = require("./self");
1.18 +const timer = require("./timers");
1.19 +const unload = require("./system/unload");
1.20 +const { emit, on, off } = require("./event/core");
1.21 +const { defer } = require('./core/promise');
1.22 +
1.23 +const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
1.24 +
1.25 +const WRITE_PERIOD_PREF = "extensions.addon-sdk.simple-storage.writePeriod";
1.26 +const WRITE_PERIOD_DEFAULT = 300000; // 5 minutes
1.27 +
1.28 +const QUOTA_PREF = "extensions.addon-sdk.simple-storage.quota";
1.29 +const QUOTA_DEFAULT = 5242880; // 5 MiB
1.30 +
1.31 +const JETPACK_DIR_BASENAME = "jetpack";
1.32 +
1.33 +Object.defineProperties(exports, {
1.34 + storage: {
1.35 + enumerable: true,
1.36 + get: function() { return manager.root; },
1.37 + set: function(value) { manager.root = value; }
1.38 + },
1.39 + quotaUsage: {
1.40 + get: function() { return manager.quotaUsage; }
1.41 + }
1.42 +});
1.43 +
1.44 +function getHash(data) {
1.45 + let { promise, resolve } = defer();
1.46 +
1.47 + let crypto = Cc["@mozilla.org/security/hash;1"].createInstance(Ci.nsICryptoHash);
1.48 + crypto.init(crypto.MD5);
1.49 +
1.50 + let listener = {
1.51 + onStartRequest: function() { },
1.52 +
1.53 + onDataAvailable: function(request, context, inputStream, offset, count) {
1.54 + crypto.updateFromStream(inputStream, count);
1.55 + },
1.56 +
1.57 + onStopRequest: function(request, context, status) {
1.58 + resolve(crypto.finish(false));
1.59 + }
1.60 + };
1.61 +
1.62 + let converter = Cc["@mozilla.org/intl/scriptableunicodeconverter"].
1.63 + createInstance(Ci.nsIScriptableUnicodeConverter);
1.64 + converter.charset = "UTF-8";
1.65 + let stream = converter.convertToInputStream(data);
1.66 + let pump = Cc["@mozilla.org/network/input-stream-pump;1"].
1.67 + createInstance(Ci.nsIInputStreamPump);
1.68 + pump.init(stream, -1, -1, 0, 0, true);
1.69 + pump.asyncRead(listener, null);
1.70 +
1.71 + return promise;
1.72 +}
1.73 +
1.74 +function writeData(filename, data) {
1.75 + let { promise, resolve, reject } = defer();
1.76 +
1.77 + let stream = file.open(filename, "w");
1.78 + try {
1.79 + stream.writeAsync(data, err => {
1.80 + if (err)
1.81 + reject(err);
1.82 + else
1.83 + resolve();
1.84 + });
1.85 + }
1.86 + catch (err) {
1.87 + // writeAsync closes the stream after it's done, so only close on error.
1.88 + stream.close();
1.89 + reject(err);
1.90 + }
1.91 +
1.92 + return promise;
1.93 +}
1.94 +
1.95 +// A generic JSON store backed by a file on disk. This should be isolated
1.96 +// enough to move to its own module if need be...
1.97 +function JsonStore(options) {
1.98 + this.filename = options.filename;
1.99 + this.quota = options.quota;
1.100 + this.writePeriod = options.writePeriod;
1.101 + this.onOverQuota = options.onOverQuota;
1.102 + this.onWrite = options.onWrite;
1.103 + this.hash = null;
1.104 + unload.ensure(this);
1.105 + this.startTimer();
1.106 +}
1.107 +
1.108 +JsonStore.prototype = {
1.109 + // The store's root.
1.110 + get root() {
1.111 + return this.isRootInited ? this._root : {};
1.112 + },
1.113 +
1.114 + // Performs some type checking.
1.115 + set root(val) {
1.116 + let types = ["array", "boolean", "null", "number", "object", "string"];
1.117 + if (types.indexOf(typeof(val)) < 0) {
1.118 + throw new Error("storage must be one of the following types: " +
1.119 + types.join(", "));
1.120 + }
1.121 + this._root = val;
1.122 + return val;
1.123 + },
1.124 +
1.125 + // True if the root has ever been set (either via the root setter or by the
1.126 + // backing file's having been read).
1.127 + get isRootInited() {
1.128 + return this._root !== undefined;
1.129 + },
1.130 +
1.131 + // Percentage of quota used, as a number [0, Inf). > 1 implies over quota.
1.132 + // Undefined if there is no quota.
1.133 + get quotaUsage() {
1.134 + return this.quota > 0 ?
1.135 + JSON.stringify(this.root).length / this.quota :
1.136 + undefined;
1.137 + },
1.138 +
1.139 + startTimer: function JsonStore_startTimer() {
1.140 + timer.setTimeout(() => {
1.141 + this.write().then(this.startTimer.bind(this));
1.142 + }, this.writePeriod);
1.143 + },
1.144 +
1.145 + // Removes the backing file and all empty subdirectories.
1.146 + purge: function JsonStore_purge() {
1.147 + try {
1.148 + // This'll throw if the file doesn't exist.
1.149 + file.remove(this.filename);
1.150 + this.hash = null;
1.151 + let parentPath = this.filename;
1.152 + do {
1.153 + parentPath = file.dirname(parentPath);
1.154 + // This'll throw if the dir isn't empty.
1.155 + file.rmdir(parentPath);
1.156 + } while (file.basename(parentPath) !== JETPACK_DIR_BASENAME);
1.157 + }
1.158 + catch (err) {}
1.159 + },
1.160 +
1.161 + // Initializes the root by reading the backing file.
1.162 + read: function JsonStore_read() {
1.163 + try {
1.164 + let str = file.read(this.filename);
1.165 +
1.166 + // Ideally we'd log the parse error with console.error(), but logged
1.167 + // errors cause tests to fail. Supporting "known" errors in the test
1.168 + // harness appears to be non-trivial. Maybe later.
1.169 + this.root = JSON.parse(str);
1.170 + let self = this;
1.171 + getHash(str).then(hash => this.hash = hash);
1.172 + }
1.173 + catch (err) {
1.174 + this.root = {};
1.175 + this.hash = null;
1.176 + }
1.177 + },
1.178 +
1.179 + // Cleans up on unload. If unloading because of uninstall, the store is
1.180 + // purged; otherwise it's written.
1.181 + unload: function JsonStore_unload(reason) {
1.182 + timer.clearTimeout(this.writeTimer);
1.183 + this.writeTimer = null;
1.184 +
1.185 + if (reason === "uninstall")
1.186 + this.purge();
1.187 + else
1.188 + this.write();
1.189 + },
1.190 +
1.191 + // True if the root is an empty object.
1.192 + get _isEmpty() {
1.193 + if (this.root && typeof(this.root) === "object") {
1.194 + let empty = true;
1.195 + for (let key in this.root) {
1.196 + empty = false;
1.197 + break;
1.198 + }
1.199 + return empty;
1.200 + }
1.201 + return false;
1.202 + },
1.203 +
1.204 + // Writes the root to the backing file, notifying write observers when
1.205 + // complete. If the store is over quota or if it's empty and the store has
1.206 + // never been written, nothing is written and write observers aren't notified.
1.207 + write: Task.async(function JsonStore_write() {
1.208 + // Don't write if the root is uninitialized or if the store is empty and the
1.209 + // backing file doesn't yet exist.
1.210 + if (!this.isRootInited || (this._isEmpty && !file.exists(this.filename)))
1.211 + return;
1.212 +
1.213 + let data = JSON.stringify(this.root);
1.214 +
1.215 + // If the store is over quota, don't write. The current under-quota state
1.216 + // should persist.
1.217 + if ((this.quota > 0) && (data.length > this.quota)) {
1.218 + this.onOverQuota(this);
1.219 + return;
1.220 + }
1.221 +
1.222 + // Hash the data to compare it to any previously written data
1.223 + let hash = yield getHash(data);
1.224 +
1.225 + if (hash == this.hash)
1.226 + return;
1.227 +
1.228 + // Finally, write.
1.229 + try {
1.230 + yield writeData(this.filename, data);
1.231 +
1.232 + this.hash = hash;
1.233 + if (this.onWrite)
1.234 + this.onWrite(this);
1.235 + }
1.236 + catch (err) {
1.237 + console.error("Error writing simple storage file: " + this.filename);
1.238 + console.error(err);
1.239 + }
1.240 + })
1.241 +};
1.242 +
1.243 +
1.244 +// This manages a JsonStore singleton and tailors its use to simple storage.
1.245 +// The root of the JsonStore is lazy-loaded: The backing file is only read the
1.246 +// first time the root's gotten.
1.247 +let manager = ({
1.248 + jsonStore: null,
1.249 +
1.250 + // The filename of the store, based on the profile dir and extension ID.
1.251 + get filename() {
1.252 + let storeFile = Cc["@mozilla.org/file/directory_service;1"].
1.253 + getService(Ci.nsIProperties).
1.254 + get("ProfD", Ci.nsIFile);
1.255 + storeFile.append(JETPACK_DIR_BASENAME);
1.256 + storeFile.append(jpSelf.id);
1.257 + storeFile.append("simple-storage");
1.258 + file.mkpath(storeFile.path);
1.259 + storeFile.append("store.json");
1.260 + return storeFile.path;
1.261 + },
1.262 +
1.263 + get quotaUsage() {
1.264 + return this.jsonStore.quotaUsage;
1.265 + },
1.266 +
1.267 + get root() {
1.268 + if (!this.jsonStore.isRootInited)
1.269 + this.jsonStore.read();
1.270 + return this.jsonStore.root;
1.271 + },
1.272 +
1.273 + set root(val) {
1.274 + return this.jsonStore.root = val;
1.275 + },
1.276 +
1.277 + unload: function manager_unload() {
1.278 + off(this);
1.279 + },
1.280 +
1.281 + new: function manager_constructor() {
1.282 + let manager = Object.create(this);
1.283 + unload.ensure(manager);
1.284 +
1.285 + manager.jsonStore = new JsonStore({
1.286 + filename: manager.filename,
1.287 + writePeriod: prefs.get(WRITE_PERIOD_PREF, WRITE_PERIOD_DEFAULT),
1.288 + quota: prefs.get(QUOTA_PREF, QUOTA_DEFAULT),
1.289 + onOverQuota: emit.bind(null, exports, "OverQuota")
1.290 + });
1.291 +
1.292 + return manager;
1.293 + }
1.294 +}).new();
1.295 +
1.296 +exports.on = on.bind(null, exports);
1.297 +exports.removeListener = function(type, listener) {
1.298 + off(exports, type, listener);
1.299 +};
