1 files changed, 70 insertions, 0 deletions
diff --git a/toolkit/components/antitracking/URLDecorationAnnotationsService.sys.mjs b/toolkit/components/antitracking/URLDecorationAnnotationsService.sys.mjs
new file mode 100644
index 0000000000..ca285e972d
--- /dev/null
+++ b/toolkit/components/antitracking/URLDecorationAnnotationsService.sys.mjs
@@ -0,0 +1,70 @@
+/* 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/. */
+
+export function URLDecorationAnnotationsService() {}
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  RemoteSettings: "resource://services-settings/remote-settings.sys.mjs",
+});
+
+const COLLECTION_NAME = "anti-tracking-url-decoration";
+const PREF_NAME = "privacy.restrict3rdpartystorage.url_decorations";
+
+URLDecorationAnnotationsService.prototype = {
+  classID: Components.ID("{5874af6d-5719-4e1b-b155-ef4eae7fcb32}"),
+  QueryInterface: ChromeUtils.generateQI([
+    "nsIObserver",
+    "nsIURLDecorationAnnotationsService",
+  ]),
+
+  _initialized: false,
+  _prefBranch: null,
+
+  onDataAvailable(entries) {
+    // Use this technique in order to ensure the pref cannot be changed by the
+    // user e.g. through about:config.  This preferences is only intended as a
+    // mechanism for reflecting this data to content processes.
+    if (this._prefBranch === null) {
+      this._prefBranch = Services.prefs.getDefaultBranch("");
+    }
+
+    const branch = this._prefBranch;
+    branch.unlockPref(PREF_NAME);
+    branch.setStringPref(
+      PREF_NAME,
+      entries.map(x => x.token.replace(/ /, "%20")).join(" ")
+    );
+    branch.lockPref(PREF_NAME);
+  },
+
+  observe(aSubject, aTopic, aData) {
+    if (aTopic == "profile-after-change") {
+      this.ensureUpdated();
+    }
+  },
+
+  ensureUpdated() {
+    if (this._initialized) {
+      return Promise.resolve();
+    }
+    this._initialized = true;
+
+    const client = lazy.RemoteSettings(COLLECTION_NAME);
+    client.on("sync", event => {
+      let {
+        data: { current },
+      } = event;
+      this.onDataAvailable(current);
+    });
+
+    // Now trigger an update from the server if necessary to get a fresh copy
+    // of the data
+    return client.get({}).then(entries => {
+      this.onDataAvailable(entries);
+      return undefined;
+    });
+  },
+};