/* 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, You can obtain one at
http://mozilla.org/MPL/2.0/. */
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
AsyncShutdown: "resource://gre/modules/AsyncShutdown.sys.mjs",
CommonUtils: "resource://services-common/utils.sys.mjs",
IDBHelpers: "resource://services-settings/IDBHelpers.sys.mjs",
ObjectUtils: "resource://gre/modules/ObjectUtils.sys.mjs",
Utils: "resource://services-settings/Utils.sys.mjs",
});
ChromeUtils.defineLazyGetter(lazy, "console", () => lazy.Utils.log);
/**
* Database is a tiny wrapper with the objective
* of providing major kinto-offline-client collection API.
* (with the objective of getting rid of kinto-offline-client)
*/
export class Database {
static destroy() {
return destroyIDB();
}
constructor(identifier) {
ensureShutdownBlocker();
this.identifier = identifier;
}
async list(options = {}) {
const { filters = {}, order = "" } = options;
let results = [];
try {
await executeIDB(
"records",
(store, rejectTransaction) => {
// Fast-path the (very common) no-filters case
if (lazy.ObjectUtils.isEmpty(filters)) {
const range = IDBKeyRange.only(this.identifier);
const request = store.index("cid").getAll(range);
request.onsuccess = e => {
results = e.target.result;
};
return;
}
const request = store
.index("cid")
.openCursor(IDBKeyRange.only(this.identifier));
const objFilters = transformSubObjectFilters(filters);
request.onsuccess = event => {
try {
const cursor = event.target.result;
if (cursor) {
const { value } = cursor;
if (lazy.Utils.filterObject(objFilters, value)) {
results.push(value);
}
cursor.continue();
}
} catch (ex) {
rejectTransaction(ex);
}
};
},
{ mode: "readonly" }
);
} catch (e) {
throw new lazy.IDBHelpers.IndexedDBError(e, "list()", this.identifier);
}
// Remove IDB key field from results.
for (const result of results) {
delete result._cid;
}
return order ? lazy.Utils.sortObjects(order, results) : results;
}
async importChanges(metadata, timestamp, records = [], options = {}) {
const { clear = false } = options;
const _cid = this.identifier;
try {
await executeIDB(
["collections", "timestamps", "records"],
(stores, rejectTransaction) => {
const [storeMetadata, storeTimestamps, storeRecords] = stores;
if (clear) {
// Our index is over the _cid and id fields. We want to remove
// all of the items in the collection for which the object was
// created, ie with _cid == this.identifier.
// We would like to just tell IndexedDB:
// store.index(IDBKeyRange.only(this.identifier)).delete();
// to delete all records matching the first part of the 2-part key.
// Unfortunately such an API does not exist.
// While we could iterate over the index with a cursor, we'd do
// a roundtrip to PBackground for each item. Once you have 1000
// items, the result is very slow because of all the overhead of
// jumping between threads and serializing/deserializing.
// So instead, we tell the store to delete everything between
// "our" _cid identifier, and what would be the next identifier
// (via lexicographical sorting). Unfortunately there does not
// seem to be a way to specify bounds for all items that share
// the same first part of the key using just that first part, hence
// the use of the hypothetical [] for the second part of the end of
// the bounds.
storeRecords.delete(
IDBKeyRange.bound([_cid], [_cid, []], false, true)
);
}
// Store or erase metadata.
if (metadata === null) {
storeMetadata.delete(_cid);
} else if (metadata) {
storeMetadata.put({ cid: _cid, metadata });
}
// Store or erase timestamp.
if (timestamp === null) {
storeTimestamps.delete(_cid);
} else if (timestamp) {
storeTimestamps.put({ cid: _cid, value: timestamp });
}
if (!records.length) {
return;
}
// Separate tombstones from creations/updates.
const toDelete = records.filter(r => r.deleted);
const toInsert = records.filter(r => !r.deleted);
lazy.console.debug(
`${_cid} ${toDelete.length} to delete, ${toInsert.length} to insert`
);
// Delete local records for each tombstone.
lazy.IDBHelpers.bulkOperationHelper(
storeRecords,
{
reject: rejectTransaction,
completion() {
// Overwrite all other data.
lazy.IDBHelpers.bulkOperationHelper(
storeRecords,
{
reject: rejectTransaction,
},
"put",
toInsert.map(item => ({ ...item, _cid }))
);
},
},
"delete",
toDelete.map(item => [_cid, item.id])
);
},
{ desc: "importChanges() in " + _cid }
);
} catch (e) {
throw new lazy.IDBHelpers.IndexedDBError(e, "importChanges()", _cid);
}
}
async getLastModified() {
let entry = null;
try {
await executeIDB(
"timestamps",
store => {
store.get(this.identifier).onsuccess = e => (entry = e.target.result);
},
{ mode: "readonly" }
);
} catch (e) {
throw new lazy.IDBHelpers.IndexedDBError(
e,
"getLastModified()",
this.identifier
);
}
if (!entry) {
return null;
}
// Some distributions where released with a modified dump that did not
// contain timestamps for last_modified. Work around this here, and return
// the timestamp as zero, so that the entries should get updated.
if (isNaN(entry.value)) {
lazy.console.warn(`Local timestamp is NaN for ${this.identifier}`);
return 0;
}
return entry.value;
}
async getMetadata() {
let entry = null;
try {
await executeIDB(
"collections",
store => {
store.get(this.identifier).onsuccess = e => (entry = e.target.result);
},
{ mode: "readonly" }
);
} catch (e) {
throw new lazy.IDBHelpers.IndexedDBError(
e,
"getMetadata()",
this.identifier
);
}
return entry ? entry.metadata : null;
}
async getAttachment(attachmentId) {
let entry = null;
try {
await executeIDB(
"attachments",
store => {
store.get([this.identifier, attachmentId]).onsuccess = e => {
entry = e.target.result;
};
},
{ mode: "readonly" }
);
} catch (e) {
throw new lazy.IDBHelpers.IndexedDBError(
e,
"getAttachment()",
this.identifier
);
}
return entry ? entry.attachment : null;
}
async saveAttachment(attachmentId, attachment) {
return await this.saveAttachments([[attachmentId, attachment]]);
}
async saveAttachments(idsAndBlobs) {
try {
await executeIDB(
"attachments",
store => {
for (const [attachmentId, attachment] of idsAndBlobs) {
if (attachment) {
store.put({ cid: this.identifier, attachmentId, attachment });
} else {
store.delete([this.identifier, attachmentId]);
}
}
},
{
desc:
"saveAttachments(<" +
idsAndBlobs.length +
" items>) in " +
this.identifier,
}
);
} catch (e) {
throw new lazy.IDBHelpers.IndexedDBError(
e,
"saveAttachments()",
this.identifier
);
}
}
async hasAttachments() {
let count = 0;
try {
const range = IDBKeyRange.bound(
[this.identifier],
[this.identifier, []],
false,
true
);
await executeIDB(
"attachments",
store => {
store.count(range).onsuccess = e => {
count = e.target.result;
};
},
{ mode: "readonly" }
);
} catch (e) {
throw new lazy.IDBHelpers.IndexedDBError(
e,
"hasAttachments()",
this.identifier
);
}
return count > 0;
}
/**
* Delete all attachments which don't match any record.
*
* Attachments are linked to records, except when a fixed `attachmentId` is used.
* A record can be updated or deleted, potentially by deleting a record and restoring an updated v
ersion
* of the record with the same ID. Potentially leaving orphaned attachments in the database.
* Since we run the pruning logic after syncing, any attachment without a
* matching record can be discarded as they will be unreachable forever.
*
* @param {Array<String>} excludeIds List of attachments IDs to exclude from pruning.
*/
async pruneAttachments(excludeIds) {
const _cid = this.identifier;
let deletedCount = 0;
try {
await executeIDB(
["attachments", "records"],
async (stores, rejectTransaction) => {
const [attachmentsStore, recordsStore] = stores;
// List all stored attachments.
// All keys ≥ [_cid, ..] && < [_cid, []]. See comment in `importChanges()`
const rangeAllKeys = IDBKeyRange.bound(
[_cid],
[_cid, []],
false,
true
);
const allAttachments = await new Promise((resolve, reject) => {
const request = attachmentsStore.getAll(rangeAllKeys);
request.onsuccess = e => resolve(e.target.result);
request.onerror = e => reject(e);
});
if (!allAttachments.length) {
lazy.console.debug(
`${this.identifier} No attachments in IDB cache. Nothing to do.`
);
return;
}
// List all stored records.
const allRecords = await new Promise((resolve, reject) => {
const rangeAllIndexed = IDBKeyRange.only(_cid);
const request = recordsStore.index("cid").getAll(rangeAllIndexed);
request.onsuccess = e => resolve(e.target.result);
request.onerror = e => reject(e);
});
// Compare known records IDs to those stored along the attachments.
const currentRecordsIDs = new Set(allRecords.map(r => r.id));
const attachmentsToDelete = allAttachments.reduce((acc, entry) => {
// Skip excluded attachments.
if (excludeIds.includes(entry.attachmentId)) {
return acc;
}
// Delete attachment if associated record does not exist.
if (!currentRecordsIDs.has(entry.attachment.record.id)) {
acc.push([_cid, entry.attachmentId]);
}
return acc;
}, []);
// Perform a bulk delete of all obsolete attachments.
lazy.console.debug(
`${this.identifier} Bulk delete ${attachmentsToDelete.length} obsolete attachments`
);
lazy.IDBHelpers.bulkOperationHelper(
attachmentsStore,
{
reject: rejectTransaction,
},
"delete",
attachmentsToDelete
);
deletedCount = attachmentsToDelete.length;
},
{ desc: "pruneAttachments() in " + this.identifier }
);
} catch (e) {
throw new lazy.IDBHelpers.IndexedDBError(
e,
"pruneAttachments()",
this.identifier
);
}
return deletedCount;
}
async clear() {
try {
await this.importChanges(null, null, [], { clear: true });
} catch (e) {
throw new lazy.IDBHelpers.IndexedDBError(e, "clear()", this.identifier);
}
}
/*
* Methods used by unit tests.
*/
async create(record) {
if (!("id" in record)) {
record = { ...record, id: lazy.CommonUtils.generateUUID() };
}
try {
await executeIDB(
"records",
store => {
store.add({ ...record, _cid: this.identifier });
},
{ desc: "create() in " + this.identifier }
);
} catch (e) {
throw new lazy.IDBHelpers.IndexedDBError(e, "create()", this.identifier);
}
return record;
}
async update(record) {
try {
await executeIDB(
"records",
store => {
store.put({ ...record, _cid: this.identifier });
},
{ desc: "update() in " + this.identifier }
);
} catch (e) {
throw new lazy.IDBHelpers.IndexedDBError(e, "update()", this.identifier);
}
}
async delete(recordId) {
try {
await executeIDB(
"records",
store => {
store.delete([this.identifier, recordId]); // [_cid, id]
},
{ desc: "delete() in " + this.identifier }
);
} catch (e) {
throw new lazy.IDBHelpers.IndexedDBError(e, "delete()", this.identifier);
}
}
}
let gDB = null;
let gDBPromise = null;
/**
* This function attempts to ensure `gDB` points to a valid database value.
* If gDB is already a database, it will do no-op (but this may take a
* microtask or two).
* If opening the database fails, it will throw an IndexedDBError.
*/
async function openIDB() {
// We can be called multiple times in a race; always ensure that when
// we complete, `gDB` is no longer null, but avoid doing the actual
// IndexedDB work more than once.
if (!gDBPromise) {
// Open and initialize/upgrade if needed.
gDBPromise = lazy.IDBHelpers.openIDB();
}
let db = await gDBPromise;
if (!gDB) {
gDB = db;
}
}
const gPendingReadOnlyTransactions = new Set();
const gPendingWriteOperations = new Set();
/**
* Helper to wrap some IDBObjectStore operations into a promise.
*
* @param {IDBDatabase} db
* @param {String|String[]} storeNames - either a string or an array of strings.
* @param {function} callback
* @param {Object} options
* @param {String} options.mode
* @param {String} options.desc for shutdown tracking.
*/
async function executeIDB(storeNames, callback, options = {}) {
if (!gDB) {
// Check if we're shutting down. Services.startup.shuttingDown will
// be true sooner, but is never true in xpcshell tests, so we check
// both that and a bool we set ourselves when `profile-before-change`
// starts.
if (gShutdownStarted || Services.startup.shuttingDown) {
throw new lazy.IDBHelpers.ShutdownError(
"The application is shutting down",
"execute()"
);
}
await openIDB();
} else {
// Even if we have a db, wait a tick to avoid making IndexedDB sad.
// We should be able to remove this once bug 1626935 is fixed.
await Promise.resolve();
}
// Check for shutdown again as we've await'd something...
if (!gDB && (gShutdownStarted || Services.startup.shuttingDown)) {
throw new lazy.IDBHelpers.ShutdownError(
"The application is shutting down",
"execute()"
);
}
// Start the actual transaction:
const { mode = "readwrite", desc = "" } = options;
let { promise, transaction } = lazy.IDBHelpers.executeIDB(
gDB,
storeNames,
mode,
callback,
desc
);
// We track all readonly transactions and abort them at shutdown.
// We track all readwrite ones and await their completion at shutdown
// (to avoid dataloss when writes fail).
// We use a `.finally()` clause for this; it'll run the function irrespective
// of whether the promise resolves or rejects, and the promise it returns
// will resolve/reject with the same value.
let finishedFn;
if (mode == "readonly") {
gPendingReadOnlyTransactions.add(transaction);
finishedFn = () => gPendingReadOnlyTransactions.delete(transaction);
} else {
let obj = { promise, desc };
gPendingWriteOperations.add(obj);
finishedFn = () => gPendingWriteOperations.delete(obj);
}
return promise.finally(finishedFn);
}
async function destroyIDB() {
if (gDB) {
if (gShutdownStarted || Services.startup.shuttingDown) {
throw new lazy.IDBHelpers.ShutdownError(
"The application is shutting down",
"destroyIDB()"
);
}
// This will return immediately; the actual close will happen once
// there are no more running transactions.
gDB.close();
const allTransactions = new Set([
...gPendingWriteOperations,
...gPendingReadOnlyTransactions,
]);
for (let transaction of Array.from(allTransactions)) {
try {
transaction.abort();
} catch (ex) {
// Ignore errors to abort transactions, we'll destroy everything.
}
}
}
gDB = null;
gDBPromise = null;
return lazy.IDBHelpers.destroyIDB();
}
function makeNestedObjectFromArr(arr, val, nestedFiltersObj) {
const last = arr.length - 1;
return arr.reduce((acc, cv, i) => {
if (i === last) {
return (acc[cv] = val);
} else if (Object.prototype.hasOwnProperty.call(acc, cv)) {
return acc[cv];
}
return (acc[cv] = {});
}, nestedFiltersObj);
}
function transformSubObjectFilters(filtersObj) {
const transformedFilters = {};
for (const [key, val] of Object.entries(filtersObj)) {
const keysArr = key.split(".");
makeNestedObjectFromArr(keysArr, val, transformedFilters);
}
return transformedFilters;
}
// We need to expose this wrapper function so we can test
// shutdown handling.
Database._executeIDB = executeIDB;
let gShutdownStarted = false;
// Test-only helper to be able to test shutdown multiple times:
Database._cancelShutdown = () => {
gShutdownStarted = false;
};
let gShutdownBlocker = false;
Database._shutdownHandler = () => {
gShutdownStarted = true;
const NS_ERROR_DOM_INDEXEDDB_NOT_ALLOWED_ERR = 0x80660006;
// Duplicate the list (to avoid it being modified) and then
// abort all read-only transactions.
for (let transaction of Array.from(gPendingReadOnlyTransactions)) {
try {
transaction.abort();
} catch (ex) {
// Ensure we don't throw/break, because either way we're in shutdown.
// In particular, `transaction.abort` can throw if the transaction
// is complete, ie if we manage to get called in between the
// transaction completing, and our completion handler being called
// to remove the item from the set. We don't care about that.
if (ex.result != NS_ERROR_DOM_INDEXEDDB_NOT_ALLOWED_ERR) {
// Report any other errors:
console.error(ex);
}
}
}
if (gDB) {
// This will return immediately; the actual close will happen once
// there are no more running transactions.
gDB.close();
gDB = null;
}
gDBPromise = null;
return Promise.allSettled(
Array.from(gPendingWriteOperations).map(op => op.promise)
);
};
function ensureShutdownBlocker() {
if (gShutdownBlocker) {
return;
}
gShutdownBlocker = true;
lazy.AsyncShutdown.profileBeforeChange.addBlocker(
"RemoteSettingsClient - finish IDB access.",
Database._shutdownHandler,
{
fetchState() {
return Array.from(gPendingWriteOperations).map(op => op.desc);
},
}
);
}
