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/* 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,
/**
* A worker dedicated to Remote Settings.
*/
// These files are imported into the worker scope, and are not shared singletons
// with the main thread.
/* eslint-disable mozilla/reject-import-system-module-from-non-system */
/* eslint-enable mozilla/reject-import-system-module-from-non-system */
const IDB_RECORDS_STORE = "records";
const IDB_TIMESTAMPS_STORE = "timestamps";
let gShutdown = false;
const Agent = {
/**
* Return the canonical JSON serialization of the specified records.
* It has to match what is done on the server (See Kinto/kinto-signer).
*
* @param {Array<Object>} records
* @param {String} timestamp
* @returns {String}
*/
async canonicalStringify(records, timestamp) {
// Sort list by record id.
let allRecords = records.sort((a, b) => {
if (a.id < b.id) {
return -1;
}
return a.id > b.id ? 1 : 0;
});
// All existing records are replaced by the version from the server
// and deleted records are removed.
for (let i = 0; i < allRecords.length /* no increment! */; ) {
const rec = allRecords[i];
const next = allRecords[i + 1];
if ((next && rec.id == next.id) || rec.deleted) {
allRecords.splice(i, 1); // remove local record
} else {
i++;
}
}
const toSerialize = {
last_modified: "" + timestamp,
data: allRecords,
};
return CanonicalJSON.stringify(toSerialize, jsesc);
},
/**
* If present, import the JSON file into the Remote Settings IndexedDB
* for the specified bucket and collection.
* (eg. blocklists/certificates, main/onboarding)
* @param {String} bucket
* @param {String} collection
* @returns {int} Number of records loaded from dump or -1 if no dump found.
*/
async importJSONDump(bucket, collection) {
const { data: records, timestamp } = await SharedUtils.loadJSONDump(
bucket,
collection
);
if (records === null) {
// Return -1 if file is missing.
return -1;
}
if (gShutdown) {
throw new Error("Can't import when we've started shutting down.");
}
await importDumpIDB(bucket, collection, records, timestamp);
return records.length;
},
/**
* Check that the specified file matches the expected size and SHA-256 hash.
* @param {String} fileUrl file URL to read from
* @param {Number} size expected file size
* @param {String} size expected file SHA-256 as hex string
* @returns {boolean}
*/
async checkFileHash(fileUrl, size, hash) {
let resp;
try {
resp = await fetch(fileUrl);
} catch (e) {
// File does not exist.
return false;
}
const buffer = await resp.arrayBuffer();
return SharedUtils.checkContentHash(buffer, size, hash);
},
async prepareShutdown() {
gShutdown = true;
// Ensure we can iterate and abort (which may delete items) by cloning
// the list.
let transactions = Array.from(gPendingTransactions);
for (let transaction of transactions) {
try {
transaction.abort();
} catch (ex) {
// We can hit this case if the transaction has finished but
// we haven't heard about it yet.
}
}
},
_test_only_import(bucket, collection, records, timestamp) {
return importDumpIDB(bucket, collection, records, timestamp);
},
};
/**
* Wrap worker invocations in order to return the `callbackId` along
* the result. This will allow to transform the worker invocations
* into promises in `RemoteSettingsWorker.sys.mjs`.
*/
self.onmessage = event => {
const { callbackId, method, args = [] } = event.data;
Agent[method](...args)
.then(result => {
self.postMessage({ callbackId, result });
})
.catch(error => {
console.log(`RemoteSettingsWorker error: ${error}`);
self.postMessage({ callbackId, error: "" + error });
});
};
let gPendingTransactions = new Set();
/**
* Import the records into the Remote Settings Chrome IndexedDB.
*
* Note: This duplicates some logics from `kinto-offline-client.sys.mjs`.
*
* @param {String} bucket
* @param {String} collection
* @param {Array<Object>} records
* @param {Number} timestamp
*/
async function importDumpIDB(bucket, collection, records, timestamp) {
// Open the DB. It will exist since if we are running this, it means
// we already tried to read the timestamp in `remote-settings.sys.mjs`
const db = await IDBHelpers.openIDB(false /* do not allow upgrades */);
// try...finally to ensure we always close the db.
try {
if (gShutdown) {
throw new Error("Can't import when we've started shutting down.");
}
// Each entry of the dump will be stored in the records store.
// They are indexed by `_cid`.
const cid = bucket + "/" + collection;
// We can just modify the items in-place, as we got them from SharedUtils.loadJSONDump().
records.forEach(item => {
item._cid = cid;
});
// Store the collection timestamp.
let { transaction, promise } = IDBHelpers.executeIDB(
db,
[IDB_RECORDS_STORE, IDB_TIMESTAMPS_STORE],
"readwrite",
([recordsStore, timestampStore], rejectTransaction) => {
// Wipe before loading
recordsStore.delete(IDBKeyRange.bound([cid], [cid, []], false, true));
IDBHelpers.bulkOperationHelper(
recordsStore,
{
reject: rejectTransaction,
completion() {
timestampStore.put({ cid, value: timestamp });
},
},
"put",
records
);
}
);
gPendingTransactions.add(transaction);
promise = promise.finally(() => gPendingTransactions.delete(transaction));
await promise;
} finally {
// Close now that we're done.
db.close();
}
}