Source code
Revision control
Copy as Markdown
Other Tools
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
const DEBUG = false;
function debug(s) {
dump("-*- NotificationDB component: " + s + "\n");
}
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
});
const kMessages = [
"Notification:Save",
"Notification:Delete",
"Notification:GetAll",
];
// Given its origin and ID, produce the key that uniquely identifies
// a notification.
function makeKey(origin, id) {
return origin.concat("\t", id);
}
var NotificationDB = {
// Ensure we won't call init() while xpcom-shutdown is performed
_shutdownInProgress: false,
// A handle to the kvstore, retrieved lazily when we load the data.
_store: null,
// A promise that resolves once the store has been loaded.
// The promise doesn't resolve to a value; it merely captures the state
// of the load via its resolution.
_loadPromise: null,
// A promise that resolves once the ongoing task queue has been drained.
// The value will be reset when the queue starts again.
_queueDrainedPromise: null,
_queueDrainedPromiseResolve: null,
init() {
if (this._shutdownInProgress) {
return;
}
this.tasks = []; // read/write operation queue
this.runningTask = null;
Services.obs.addObserver(this, "xpcom-shutdown");
this.registerListeners();
// This assumes that nothing will queue a new task at profile-change-teardown phase,
// potentially replacing the _queueDrainedPromise if there was no existing task run.
lazy.AsyncShutdown.profileChangeTeardown.addBlocker(
"NotificationDB: Need to make sure that all notification messages are processed",
() => this._queueDrainedPromise
);
},
registerListeners() {
for (let message of kMessages) {
Services.ppmm.addMessageListener(message, this);
}
},
unregisterListeners() {
for (let message of kMessages) {
Services.ppmm.removeMessageListener(message, this);
}
},
observe(aSubject, aTopic) {
if (DEBUG) {
debug("Topic: " + aTopic);
}
if (aTopic == "xpcom-shutdown") {
this._shutdownInProgress = true;
Services.obs.removeObserver(this, "xpcom-shutdown");
this.unregisterListeners();
}
},
filterNonAppNotifications(notifications) {
for (let origin in notifications) {
let persistentNotificationCount = 0;
for (let id in notifications[origin]) {
if (notifications[origin][id].serviceWorkerRegistrationScope) {
persistentNotificationCount++;
} else {
delete notifications[origin][id];
}
}
if (persistentNotificationCount == 0) {
if (DEBUG) {
debug(
"Origin " + origin + " is not linked to an app manifest, deleting."
);
}
delete notifications[origin];
}
}
return notifications;
},
async maybeMigrateData() {
const oldStore = PathUtils.join(
Services.dirsvc.get("ProfD", Ci.nsIFile).path,
"notificationstore.json"
);
if (!(await IOUtils.exists(oldStore))) {
if (DEBUG) {
debug("Old store doesn't exist; not migrating data.");
}
return;
}
let data;
try {
data = await IOUtils.readUTF8(oldStore);
} catch (ex) {
// If read failed, we assume we have no notifications to migrate.
if (DEBUG) {
debug("Failed to read old store; not migrating data.");
}
return;
} finally {
// Finally, delete the old file so we don't try to migrate it again.
await IOUtils.remove(oldStore);
}
if (data.length) {
// Preprocessing phase intends to cleanly separate any migration-related
// tasks.
//
// NB: This code existed before we migrated the data to a kvstore,
// and the "migration-related tasks" it references are from an earlier
// migration. We used to do it every time we read the JSON file;
// now we do it once, when migrating the JSON file to the kvstore.
const notifications = this.filterNonAppNotifications(JSON.parse(data));
// Copy the data from the JSON file to the kvstore.
// TODO: use a transaction to improve the performance of these operations
for (const origin in notifications) {
for (const id in notifications[origin]) {
await this._store.put(
makeKey(origin, id),
JSON.stringify(notifications[origin][id])
);
}
}
}
},
// Attempt to read notification file, if it's not there we will create it.
async load() {
// Get and cache a handle to the kvstore.
const dir = PathUtils.join(PathUtils.profileDir, "notificationstore");
await IOUtils.makeDirectory(dir, { ignoreExisting: true });
this._store = await lazy.KeyValueService.getOrCreate(dir, "notifications");
// Migrate data from the old JSON file to the new kvstore if the old file
// is present in the user's profile directory.
await this.maybeMigrateData();
},
// Helper function: promise will be resolved once file exists and/or is loaded.
ensureLoaded() {
if (!this._loadPromise) {
this._loadPromise = this.load();
}
return this._loadPromise;
},
receiveMessage(message) {
if (DEBUG) {
debug("Received message:" + message.name);
}
// sendAsyncMessage can fail if the child process exits during a
// notification storage operation, so always wrap it in a try/catch.
function returnMessage(name, data) {
try {
message.target.sendAsyncMessage(name, data);
} catch (e) {
if (DEBUG) {
debug("Return message failed, " + name);
}
}
}
switch (message.name) {
case "Notification:GetAll":
this.queueTask("getall", message.data)
.then(function (notifications) {
returnMessage("Notification:GetAll:Return:OK", {
requestID: message.data.requestID,
origin: message.data.origin,
notifications,
});
})
.catch(function (error) {
returnMessage("Notification:GetAll:Return:KO", {
requestID: message.data.requestID,
origin: message.data.origin,
errorMsg: error,
});
});
break;
case "Notification:Save":
this.queueTask("save", message.data)
.then(function () {
returnMessage("Notification:Save:Return:OK", {
requestID: message.data.requestID,
});
})
.catch(function (error) {
returnMessage("Notification:Save:Return:KO", {
requestID: message.data.requestID,
errorMsg: error,
});
});
break;
case "Notification:Delete":
this.queueTask("delete", message.data)
.then(function () {
returnMessage("Notification:Delete:Return:OK", {
requestID: message.data.requestID,
});
})
.catch(function (error) {
returnMessage("Notification:Delete:Return:KO", {
requestID: message.data.requestID,
errorMsg: error,
});
});
break;
default:
if (DEBUG) {
debug("Invalid message name" + message.name);
}
}
},
// We need to make sure any read/write operations are atomic,
// so use a queue to run each operation sequentially.
queueTask(operation, data) {
if (DEBUG) {
debug("Queueing task: " + operation);
}
var defer = {};
this.tasks.push({ operation, data, defer });
var promise = new Promise(function (resolve, reject) {
defer.resolve = resolve;
defer.reject = reject;
});
// Only run immediately if we aren't currently running another task.
if (!this.runningTask) {
if (DEBUG) {
debug("Task queue was not running, starting now...");
}
this.runNextTask();
this._queueDrainedPromise = new Promise(resolve => {
this._queueDrainedPromiseResolve = resolve;
});
}
return promise;
},
runNextTask() {
if (this.tasks.length === 0) {
if (DEBUG) {
debug("No more tasks to run, queue depleted");
}
this.runningTask = null;
if (this._queueDrainedPromiseResolve) {
this._queueDrainedPromiseResolve();
} else if (DEBUG) {
debug(
"_queueDrainedPromiseResolve was null somehow, no promise to resolve"
);
}
return;
}
this.runningTask = this.tasks.shift();
// Always make sure we are loaded before performing any read/write tasks.
this.ensureLoaded()
.then(() => {
var task = this.runningTask;
switch (task.operation) {
case "getall":
return this.taskGetAll(task.data);
case "save":
return this.taskSave(task.data);
case "delete":
return this.taskDelete(task.data);
}
throw new Error(`Unknown task operation: ${task.operation}`);
})
.then(payload => {
if (DEBUG) {
debug("Finishing task: " + this.runningTask.operation);
}
this.runningTask.defer.resolve(payload);
})
.catch(err => {
if (DEBUG) {
debug(
"Error while running " + this.runningTask.operation + ": " + err
);
}
this.runningTask.defer.reject(err);
})
.then(() => {
this.runNextTask();
});
},
enumerate(origin) {
// The "from" and "to" key parameters to nsIKeyValueStore.enumerate()
// are inclusive and exclusive, respectively, and keys are tuples
// of origin and ID joined by a tab (\t), which is character code 9;
// so enumerating ["origin", "origin\n"), where the line feed (\n)
// is character code 10, enumerates all pairs with the given origin.
return this._store.enumerate(origin, `${origin}\n`);
},
async taskGetAll(data) {
if (DEBUG) {
debug("Task, getting all");
}
var origin = data.origin;
var notifications = [];
for (const { value } of await this.enumerate(origin)) {
notifications.push(JSON.parse(value));
}
if (data.tag) {
notifications = notifications.filter(n => n.tag === data.tag);
}
return notifications;
},
async taskSave(data) {
if (DEBUG) {
debug("Task, saving");
}
var origin = data.origin;
var notification = data.notification;
// We might have existing notification with this tag,
// if so we need to remove it before saving the new one.
if (notification.tag) {
for (const { key, value } of await this.enumerate(origin)) {
const oldNotification = JSON.parse(value);
if (oldNotification.tag === notification.tag) {
await this._store.delete(key);
}
}
}
await this._store.put(
makeKey(origin, notification.id),
JSON.stringify(notification)
);
},
async taskDelete(data) {
if (DEBUG) {
debug("Task, deleting");
}
await this._store.delete(makeKey(data.origin, data.id));
},
};
NotificationDB.init();