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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, You can obtain one at http://mozilla.org/MPL/2.0/. */
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
KeyValueService: "resource://gre/modules/kvstore.sys.mjs",
});
/**
* A helper to keep track of synchronization statuses.
*
* We rely on a different storage backend than for storing Remote Settings data,
* because the eventual goal is to be able to detect `IndexedDB` issues and act
* accordingly.
*/
export class SyncHistory {
// Internal reference to underlying rkv store.
#store;
/**
* @param {String} source the synchronization source (eg. `"settings-sync"`)
* @param {Object} options
* @param {int} options.size Maximum number of entries per source.
*/
constructor(source, { size } = { size: 100 }) {
this.source = source;
this.size = size;
}
/**
* Store the synchronization status. The ETag is converted and stored as
* a millisecond epoch timestamp.
* The entries with the oldest timestamps will be deleted to maintain the
* history size under the configured maximum.
*
* @param {String} etag the ETag value from the server (eg. `"1647961052593"`)
* @param {String} status the synchronization status (eg. `"success"`)
* @param {Object} infos optional additional information to keep track of
*/
async store(etag, status, infos = {}) {
const rkv = await this.#init();
const timestamp = parseInt(etag.replace('"', ""), 10);
if (Number.isNaN(timestamp)) {
throw new Error(`Invalid ETag value ${etag}`);
}
const key = `v1-${this.source}\t${timestamp}`;
const value = { timestamp, status, infos };
await rkv.put(key, JSON.stringify(value));
// Trim old entries.
const allEntries = await this.list();
for (let i = this.size; i < allEntries.length; i++) {
let { timestamp } = allEntries[i];
await rkv.delete(`v1-${this.source}\t${timestamp}`);
}
}
/**
* Retrieve the stored history entries for a certain source, sorted by
* timestamp descending.
*
* @returns {Array<Object>} a list of objects
*/
async list() {
const rkv = await this.#init();
const entries = [];
// The "from" and "to" key parameters to nsIKeyValueStore.enumerate()
// are inclusive and exclusive, respectively, and keys are tuples
// of source and datetime joined by a tab (\t), which is character code 9;
// so enumerating ["source", "source\n"), where the line feed (\n)
// is character code 10, enumerates all pairs with the given source.
for (const { value } of await rkv.enumerate(
`v1-${this.source}`,
`v1-${this.source}\n`
)) {
try {
const stored = JSON.parse(value);
entries.push({ ...stored, datetime: new Date(stored.timestamp) });
} catch (e) {
// Ignore malformed entries.
console.error(e);
}
}
// Sort entries by `timestamp` descending.
entries.sort((a, b) => (a.timestamp > b.timestamp ? -1 : 1));
return entries;
}
/**
* Return the most recent entry.
*/
async last() {
// List is sorted from newer to older.
return (await this.list())[0];
}
/**
* Wipe out the **whole** store.
*/
async clear() {
const rkv = await this.#init();
await rkv.clear();
}
/**
* Initialize the rkv store in the user profile.
*
* @returns {Object} the underlying `KeyValueService` instance.
*/
async #init() {
if (!this.#store) {
// Get and cache a handle to the kvstore.
const dir = PathUtils.join(PathUtils.profileDir, "settings");
await IOUtils.makeDirectory(dir);
this.#store = await lazy.KeyValueService.getOrCreate(dir, "synchistory");
}
return this.#store;
}
}
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