summaryrefslogtreecommitdiffstats
path: root/browser/components/newtab/lib/PersistentCache.sys.mjs
diff options
context:
space:
mode:
Diffstat (limited to 'browser/components/newtab/lib/PersistentCache.sys.mjs')
-rw-r--r--browser/components/newtab/lib/PersistentCache.sys.mjs90
1 files changed, 90 insertions, 0 deletions
diff --git a/browser/components/newtab/lib/PersistentCache.sys.mjs b/browser/components/newtab/lib/PersistentCache.sys.mjs
new file mode 100644
index 0000000000..1db9ca102e
--- /dev/null
+++ b/browser/components/newtab/lib/PersistentCache.sys.mjs
@@ -0,0 +1,90 @@
+/* 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/. */
+
+/**
+ * A file (disk) based persistent cache of a JSON serializable object.
+ */
+export class PersistentCache {
+ /**
+ * Create a cache object based on a name.
+ *
+ * @param {string} name Name of the cache. It will be used to create the filename.
+ * @param {boolean} preload (optional). Whether the cache should be preloaded from file. Defaults to false.
+ */
+ constructor(name, preload = false) {
+ this.name = name;
+ this._filename = `activity-stream.${name}.json`;
+ if (preload) {
+ this._load();
+ }
+ }
+
+ /**
+ * Set a value to be cached with the specified key.
+ *
+ * @param {string} key The cache key.
+ * @param {object} value The data to be cached.
+ */
+ async set(key, value) {
+ const data = await this._load();
+ data[key] = value;
+ await this._persist(data);
+ }
+
+ /**
+ * Get a value from the cache.
+ *
+ * @param {string} key (optional) The cache key. If not provided, we return the full cache.
+ * @returns {object} The cached data.
+ */
+ async get(key) {
+ const data = await this._load();
+ return key ? data[key] : data;
+ }
+
+ /**
+ * Load the cache into memory if it isn't already.
+ */
+ _load() {
+ return (
+ this._cache ||
+ // eslint-disable-next-line no-async-promise-executor
+ (this._cache = new Promise(async (resolve, reject) => {
+ let filepath;
+ try {
+ filepath = PathUtils.join(PathUtils.localProfileDir, this._filename);
+ } catch (error) {
+ reject(error);
+ return;
+ }
+
+ let data = {};
+ try {
+ data = await IOUtils.readJSON(filepath);
+ } catch (error) {
+ if (
+ // isInstance() is not available in node unit test. It should be safe to use instanceof as it's directly from IOUtils.
+ // eslint-disable-next-line mozilla/use-isInstance
+ !(error instanceof DOMException) ||
+ error.name !== "NotFoundError"
+ ) {
+ console.error(`Failed to parse ${this._filename}:`, error.message);
+ }
+ }
+
+ resolve(data);
+ }))
+ );
+ }
+
+ /**
+ * Persist the cache to file.
+ */
+ async _persist(data) {
+ const filepath = PathUtils.join(PathUtils.localProfileDir, this._filename);
+ await IOUtils.writeJSON(filepath, data, {
+ tmpPath: `${filepath}.tmp`,
+ });
+ }
+}