Source code
Revision control
Copy as Markdown
Other Tools
/* Copyright 2026 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { AIFeature } from "chrome://global/content/ml/AIFeature.sys.mjs";
import { FEATURES } from "chrome://global/content/ml/EngineProcess.sys.mjs";
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
MLUninstallService: "chrome://global/content/ml/Utils.sys.mjs",
});
export class PdfJsGuessAltTextFeature extends AIFeature {
static get engineId() {
return FEATURES[this.id].engineId;
}
/** @inheritdoc */
static get id() {
return "pdfjs-alt-text";
}
/** @inheritdoc */
static async enable() {
// Enable alt-text feature (regardless of method)
Services.prefs.setBoolPref("pdfjs.enableAltText", true);
// and enable guessing (ML-based) alt-text feature.
Services.prefs.setBoolPref("pdfjs.enableGuessAltText", true);
// Also allow model download.
Services.prefs.setBoolPref("pdfjs.enableAltTextModelDownload", true);
}
/** @inheritdoc */
static async disable() {
Services.prefs.setBoolPref("pdfjs.enableGuessAltText", false);
Services.prefs.setBoolPref("pdfjs.enableAltTextModelDownload", false);
Services.prefs.setBoolPref("pdfjs.enableAltText", false);
await this.uninstall();
}
static async reset() {
Services.prefs.clearUserPref("pdfjs.enableGuessAltText");
Services.prefs.clearUserPref("pdfjs.enableAltTextModelDownload");
Services.prefs.clearUserPref("pdfjs.enableAltText");
await this.uninstall();
}
static async uninstall() {
const { engineId } = this;
await lazy.MLUninstallService.uninstall({
engineIds: [engineId],
actor: engineId,
});
}
/** @inheritdoc */
static get isEnabled() {
return (
Services.prefs.getBoolPref("browser.ml.enable", false) &&
Services.prefs.getBoolPref("pdfjs.enableAltText", false) &&
Services.prefs.getBoolPref("pdfjs.enableGuessAltText", false) &&
Services.prefs.getBoolPref("pdfjs.enableAltTextModelDownload", false)
);
}
/** @inheritdoc */
static get isAllowed() {
return Services.locale.appLocaleAsBCP47.substring(0, 2) === "en";
}
static get isBlocked() {
return (
!this.isAllowed ||
!Services.prefs.getBoolPref("browser.ml.enable", false) ||
!Services.prefs.getBoolPref("pdfjs.enableAltText", false)
);
}
static get isManagedByPolicy() {
return false;
}
}