1 files changed, 189 insertions, 0 deletions
diff --git a/common/storage_client.js b/common/storage_client.js
new file mode 100644
index 0000000..39ece44
--- /dev/null
+++ b/common/storage_client.js
@@ -0,0 +1,189 @@
+/**
+* Myext storage through connection (client side)
+*
+* Copyright (C) 2021 Wojtek Kosior
+*
+* Dual-licensed under:
+*   - 0BSD license
+*   - GPLv3 or (at your option) any later version
+*/
+
+"use strict";
+
+(() => {
+    const CONNECTION_TYPE = window.CONNECTION_TYPE;
+    const TYPE_PREFIX = window.TYPE_PREFIX;
+    const list_prefixes = window.list_prefixes;
+    const make_once = window.make_once;
+    const browser = window.browser;
+
+    var call_id = 0;
+    var port;
+    var calls_waiting = new Map();
+
+    function set_call_callback(resolve, reject, func, args)
+    {
+	port.postMessage([call_id, func, args]);
+	calls_waiting.set(call_id++, [resolve, reject]);
+    }
+
+    async function remote_call(func, args)
+    {
+	return new Promise((resolve, reject) =>
+			   set_call_callback(resolve, reject, func, args));
+    }
+
+    function handle_message(message)
+    {
+	let callbacks = calls_waiting.get(message.call_id);
+	if (callbacks === undefined) {
+	    handle_change(message);
+	    return;
+	}
+
+	let [resolve, reject] = callbacks;
+	calls_waiting.delete(message.call_id);
+	if (message.error !== undefined)
+	    setTimeout(reject, 0, message.error);
+	else
+	    setTimeout(resolve, 0, message.result);
+    }
+
+    function list(name, prefix)
+    {
+	return {prefix, name, listeners : new Set()};
+    }
+
+    var scripts = list("scripts", TYPE_PREFIX.SCRIPT);
+    var bundles = list("bundles", TYPE_PREFIX.BUNDLE);
+    var pages = list("pages", TYPE_PREFIX.PAGE);
+
+    const list_by_prefix = {
+	[TYPE_PREFIX.SCRIPT] : scripts,
+	[TYPE_PREFIX.BUNDLE] : bundles,
+	[TYPE_PREFIX.PAGE] : pages
+    };
+
+    var resolve_init;
+
+    function handle_first_message(message)
+    {
+	for (let prefix of Object.keys(message))
+	    list_by_prefix[prefix].map = new Map(message[prefix]);
+
+	port.onMessage.removeListener(handle_first_message);
+	port.onMessage.addListener(handle_message);
+
+	resolve_init();
+    }
+
+    function handle_change(change)
+    {
+	let list = list_by_prefix[change.prefix];
+
+	if (change.new_val === undefined)
+	    list.map.delete(change.item);
+	else
+	    list.map.set(change.item, change.new_val);
+
+	for (let listener_callback of list.listeners)
+	    listener_callback(change);
+    }
+
+    var exports = {};
+
+    function start_connection(resolve)
+    {
+	resolve_init = resolve;
+	port = browser.runtime.connect({name : CONNECTION_TYPE.REMOTE_STORAGE});
+	port.onMessage.addListener(handle_first_message);
+    }
+
+    async function init() {
+	await new Promise((resolve, reject) => start_connection(resolve));
+	return exports;
+    }
+
+    for (let call_name of ["set", "remove", "replace", "clear"])
+	exports [call_name] = (...args) => remote_call(call_name, args);
+
+    // TODO: Much of the code below is copy-pasted from /background/storage.mjs.
+    //       This should later be refactored into a separate module
+    //       to avoid duplication.
+
+    /*
+     * Facilitate listening to changes
+     */
+
+    exports.add_change_listener = function (cb, prefixes=list_prefixes)
+    {
+	if (typeof(prefixes) === "string")
+	    prefixes = [prefixes];
+
+	for (let prefix of prefixes)
+	    list_by_prefix[prefix].listeners.add(cb);
+    }
+
+    exports.remove_change_listener = function (cb, prefixes=list_prefixes)
+    {
+	if (typeof(prefixes) === "string")
+	    prefixes = [prefixes];
+
+	for (let prefix of prefixes)
+	    list_by_prefix[prefix].listeners.delete(cb);
+    }
+
+    /* Prepare some hepler functions to get elements of a list */
+
+    function list_items_it(list, with_values=false)
+    {
+	return with_values ? list.map.entries() : list.map.keys();
+    }
+
+    function list_entries_it(list)
+    {
+	return list_items_it(list, true);
+    }
+
+    function list_items(list, with_values=false)
+    {
+	let array = [];
+
+	for (let item of list_items_it(list, with_values))
+	    array.push(item);
+
+	return array;
+    }
+
+    function list_entries(list)
+    {
+	return list_items(list, true);
+    }
+
+    exports.get = function (prefix, item)
+    {
+	return list_by_prefix[prefix].map.get(item);
+    }
+
+    exports.get_all_names = function (prefix)
+    {
+	return list_items(list_by_prefix[prefix]);
+    }
+
+    exports.get_all_names_it = function (prefix)
+    {
+	return list_items_it(list_by_prefix[prefix]);
+    }
+
+    exports.get_all = function (prefix)
+    {
+	return list_entries(list_by_prefix[prefix]);
+    }
+
+    exports.get_all_it = function (prefix)
+    {
+	return list_entries_it(list_by_prefix[prefix]);
+    }
+
+    window.get_storage = make_once(init);
+})();