facilitate querying IndexedDB for script files of resource and its dependencies

1 files changed, 152 insertions, 0 deletions

diff --git a/background/indexeddb_files_server.js b/background/indexeddb_files_server.js
new file mode 100644
index 0000000..cf78ca6
--- /dev/null
+++ b/background/indexeddb_files_server.js
@@ -0,0 +1,152 @@
+/**
+ * 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.hash_key));
+
+    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