Haketilo

/**

 * This file is part of Haketilo.

 *

 * Function: Content scripts - main script.

 *

 * Copyright (C) 2022 Wojtek Kosior

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * As additional permission under GNU GPL version 3 section 7, you

 * may distribute forms of that code without the copy of the GNU

 * GPL normally required by section 4, provided you include this

 * license notice and, in case of non-source distribution, a URL

 * through which recipients can access the Corresponding Source.

 * If you modify file(s) with this exception, you may extend this

 * exception to your version of the file(s), but you are not

 * obligated to do so. If you do not wish to do so, delete this

 * exception statement from your version.

 *

 * As a special exception to the GPL, any HTML file which merely

 * makes function calls to this code, and for that purpose

 * includes it by reference shall be deemed a separate work for

 * copyright law purposes. If you modify this code, you may extend

 * this exception to your version of the code, but you are not

 * obligated to do so. If you do not wish to do so, delete this

 * exception statement from your version.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>.

 *

 * I, Wojtek Kosior, thereby promise not to sue for violation of this file's

 * license. Although I request that you do not make use of this code in a

 * proprietary program, I am not going to enforce this in court.

 */

#IMPORT content/repo_query_cacher.js

#IMPORT content/haketilo_apis.js

#FROM common/browser.js           IMPORT browser

#FROM common/misc.js              IMPORT is_privileged_url

#FROM common/policy.js            IMPORT decide_policy, fallback_policy

#FROM content/policy_enforcing.js IMPORT enforce_blocking

#IF CHROMIUM && MV2

function synchronously_get_policy(url)

{

    const encoded_url = encodeURIComponent(url);

    const request_url = `${browser.runtime.getURL("dummy")}?url=${encoded_url}`;

    try {

	var xhttp = new XMLHttpRequest();

	xhttp.open("GET", request_url, false);

	xhttp.send();

    } catch(e) {

	console.error("Haketilo: Failure to synchronously fetch policy for url.", e);

	return fallback_policy();

    }

    try {

	const policy = /^[^?]*\?settings=(.*)$/.exec(xhttp.responseURL)[1];

	return JSON.parse(decodeURIComponent(policy));

    } catch(e) {

	console.error("Haketilo: Failure to process synchronously fetched policy for url.", e);

	return fallback_policy()

    }

}

#ENDIF

let already_run = false, resolve_page_info,

    page_info_prom = new Promise(cb => resolve_page_info = cb);

function on_page_info_request([type], sender, respond_cb) {

    if (type !== "page_info")

	return;

    page_info_prom.then(respond_cb);

    return true;

}

#IF MOZILLA || MV3

globalThis.haketilo_content_script_main = async function() {

#ELSE

async function main() {

#ENDIF

    if (already_run)

        return;

    already_run = true;

    if (is_privileged_url(document.URL))

	return;

    browser.runtime.onMessage.addListener(on_page_info_request);

    repo_query_cacher.start();

#IF MOZILLA || MV3

    try {

	var policy = decide_policy(globalThis.haketilo_pattern_tree,

				   document.URL,

				   globalThis.haketilo_default_allow,

				   globalThis.haketilo_secret);

    } catch(e) {

	console.error("Haketilo:", e);

	var policy = fallback_policy();

    }

#ELSE

    const policy = synchronously_get_policy(document.URL);

#ENDIF

    const page_info = Object.assign({url: document.URL}, policy);

    ["csp", "nonce"].forEach(prop => delete page_info[prop]);

    if ("payload" in policy) {

	const msg = ["indexeddb_files", policy.payload.identifier];

	var scripts_prom = browser.runtime.sendMessage(msg);

    }

    await enforce_blocking(policy);

    if ("payload" in policy) {

	const script_response = await scripts_prom;

	if ("error" in script_response) {

	    resolve_page_info(Object.assign(page_info, script_response));

	    return;

	} else {

	    haketilo_apis.start();

	    const version = browser.runtime.getManifest().version;

	    const scripts = [

		`window.haketilo_version = ${JSON.stringify(version)};`,

		...script_response.files

	    ];

	    for (const script_contents of scripts) {

		const html_ns = "http://www.w3.org/1999/xhtml";

		const script = document.createElementNS(html_ns, "script");

		const blobby_opts = {type: "text/javascript;charset=UTF-8"};

		const blobby = new Blob([script_contents], blobby_opts);

		script.src = URL.createObjectURL(blobby);

		script.setAttribute("nonce", policy.nonce);

		document.documentElement.append(script);

		script.remove();

	    }

	}

    }

    resolve_page_info(page_info);

}

#IF MOZILLA || MV3

function main() {

    if (globalThis.haketilo_pattern_tree !== undefined)

	globalThis.haketilo_content_script_main();

}

#ENDIF

#IF !UNIT_TEST

main();

#ENDIF