Haketilo

/**

 * This file is part of Haketilo.

 *

 * Function: Allow content scripts to query IndexedDB through messages to

 *           background script.

 *

 * Copyright (C) 2022 Wojtek Kosior <koszko@koszko.org>

 *

 * 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 common/indexeddb.js AS haketilodb

#FROM common/browser.js IMPORT browser

async function get_resource_files(getting, id) {

    if (getting.defs_by_res_id.has(id))

	return;

    getting.defs_by_res_id.set(id, null);

    const definition = await haketilodb.idb_get(getting.tx, "resource", id);

    if (!definition)

	throw {haketilo_error_type: "missing", id};

    getting.defs_by_res_id.set(id, definition);

    const file_proms = (definition.scripts || [])

	  .map(s => haketilodb.idb_get(getting.tx, "files", s.sha256));

    const deps_proms = (definition.dependencies || [])

	  .map(dep_id => get_resource_files(getting, dep_id));

    const files = (await Promise.all(file_proms)).map(f => f.contents);

    getting.files_by_res_id.set(id, files);

    await Promise.all(deps_proms);

}

function get_files_list(defs_by_res_id, files_by_res_id, root_id) {

    const processed = new Set(), to_process = [["start", root_id]],

	  trace = new Set(), files = [];

    while (to_process.length > 0) {

	const [what, id] = to_process.pop();

	if (what === "end") {

	    trace.delete(id);

	    files.push(...files_by_res_id.get(id));

	    continue;

	}

	if (trace.has(id))

	    throw {haketilo_error_type: "circular", id};

	if (processed.has(id))

	    continue;

	trace.add(id);

	to_process.push(["end", id]);

	processed.add(id);

	const ds = (defs_by_res_id.get(id).dependencies || []).reverse();

	ds.forEach(dep_id => to_process.push(["start", dep_id]));

    }

    return files;

}

async function send_resource_files(root_resource_id, send_cb) {

    const db = await haketilodb.get();

    const getting = {

	defs_by_res_id:  new Map(),

	files_by_res_id: new Map(),

	tx:              db.transaction(["files", "resource"])

    };

    let prom_cbs, prom = new Promise((...cbs) => prom_cbs = cbs);

    getting.tx.onerror = e => prom_cbs[1]({haketilo_error_type: "db", e});

    get_resource_files(getting, root_resource_id, new Set()).then(...prom_cbs);

    try {

	await prom;

	const files = get_files_list(

	    getting.defs_by_res_id,

	    getting.files_by_res_id,

	    root_resource_id

	);

	var to_send = {files};

    } catch(e) {

	if (typeof e === "object" && "haketilo_error_type" in e) {

	    if (e.haketilo_error_type === "db") {

		console.error(e.e);

		delete e.e;

	    }

	    var to_send = {error: e};

	} else {

	    console.error(e);

	    var to_send = {error: {haketilo_error_type: "other"}};

	}

    }

    send_cb(to_send);

}

function on_indexeddb_files_request([type, resource_id], sender, respond_cb) {

    if (type !== "indexeddb_files")

	return;

    send_resource_files(resource_id, respond_cb);

    return true;

}

function start() {

    browser.runtime.onMessage.addListener(on_indexeddb_files_request);

}

#EXPORT start