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-rw-r--r--background/storage.mjs380
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diff --git a/background/storage.mjs b/background/storage.mjs
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-/**
-* Myext storage manager
-*
-* Copyright (C) 2021 Wojtek Kosior
-*
-* Dual-licensed under:
-* - 0BSD license
-* - GPLv3 or (at your option) any later version
-*/
-
-import {TYPE_PREFIX, TYPE_NAME, list_prefixes} from '/common/stored_types.mjs';
-import {make_lock, lock, unlock} from '/common/lock.mjs';
-import make_once from '/common/once.mjs';
-import browser from '/common/browser.mjs';
-
-"use strict";
-
-var exports = {};
-
-/* We're yet to decide how to handle errors... */
-
-/* Here are some basic wrappers for storage API functions */
-
-async function get(key)
-{
- try {
- /* Fix for fact that Chrome does not use promises here */
- let promise = window.browser === undefined ?
- new Promise((resolve, reject) =>
- chrome.storage.local.get(key, val => resolve(val))) :
- browser.storage.local.get(key);
-
- return (await promise)[key];
- } catch (e) {
- console.log(e);
- }
-}
-
-async function set(key, value)
-{
- try {
- return browser.storage.local.set({[key]: value});
- } catch (e) {
- console.log(e);
- }
-}
-
-async function setn(keys_and_values)
-{
- let obj = Object();
- while (keys_and_values.length > 1) {
- let value = keys_and_values.pop();
- let key = keys_and_values.pop();
- obj[key] = value;
- }
-
- try {
- return browser.storage.local.set(obj);
- } catch (e) {
- console.log(e);
- }
-}
-
-async function set_var(name, value)
-{
- return set(TYPE_PREFIX.VAR + name, value);
-}
-
-async function get_var(name)
-{
- return get(TYPE_PREFIX.VAR + name);
-}
-
-/* A special case of a persisted variable is one that contains list of items. */
-
-async function get_list_var(name)
-{
- let list = await get_var(name);
-
- return list === undefined ? [] : list;
-}
-
-/* We maintain in-memory copies of some stored lists. */
-
-async function list(prefix)
-{
- let name = TYPE_NAME[prefix] + "s"; /* Make plural. */
- let map = new Map();
-
- for (let item of await get_list_var(name))
- map.set(item, await get(prefix + item));
-
- return {map, prefix, name, listeners : new Set(), lock : make_lock()};
-}
-
-var pages;
-var bundles;
-var scripts;
-
-var list_by_prefix = {};
-
-async function init()
-{
- for (let prefix of list_prefixes)
- list_by_prefix[prefix] = await list(prefix);
-
- return exports;
-}
-
-/*
- * 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);
-}
-
-function broadcast_change(change, list)
-{
- for (let listener_callback of list.listeners)
- listener_callback(change);
-}
-
-/* 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);
-}
-
-/*
- * Below we make additional effort to update map of given kind of items
- * every time an item is added/removed to keep everything coherent.
- */
-async function set_item(item, value, list)
-{
- await lock(list.lock);
- let result = await _set_item(...arguments);
- unlock(list.lock)
- return result;
-}
-async function _set_item(item, value, list)
-{
- let key = list.prefix + item;
- let old_val = list.map.get(item);
- if (old_val === undefined) {
- let items = list_items(list);
- items.push(item);
- await setn([key, value, "_" + list.name, items]);
- } else {
- await set(key, value);
- }
-
- list.map.set(item, value)
-
- let change = {
- prefix : list.prefix,
- item,
- old_val,
- new_val : value
- };
-
- broadcast_change(change, list);
-
- return old_val;
-}
-
-// TODO: The actual idea to set value to undefined is good - this way we can
-// also set a new list of items in the same API call. But such key
-// is still stored in the storage. We need to somehow remove it later.
-// For that, we're going to have to store 1 more list of each kind.
-async function remove_item(item, list)
-{
- await lock(list.lock);
- let result = await _remove_item(...arguments);
- unlock(list.lock)
- return result;
-}
-async function _remove_item(item, list)
-{
- let old_val = list.map.get(item);
- if (old_val === undefined)
- return;
-
- let key = list.prefix + item;
- let items = list_items(list);
- let index = items.indexOf(item);
- items.splice(index, 1);
-
- await setn([key, undefined, "_" + list.name, items]);
-
- list.map.delete(item);
-
- let change = {
- prefix : list.prefix,
- item,
- old_val,
- new_val : undefined
- };
-
- broadcast_change(change, list);
-
- return old_val;
-}
-
-// TODO: same as above applies here
-async function replace_item(old_item, new_item, list, new_val=undefined)
-{
- await lock(list.lock);
- let result = await _replace_item(...arguments);
- unlock(list.lock)
- return result;
-}
-async function _replace_item(old_item, new_item, list, new_val=undefined)
-{
- let old_val = list.map.get(old_item);
- if (new_val === undefined) {
- if (old_val === undefined)
- return;
- new_val = old_val
- } else if (new_val === old_val && new_item === old_item) {
- return old_val;
- }
-
- if (old_item === new_item || old_val === undefined) {
- await _set_item(new_item, new_val, list);
- return old_val;
- }
-
- let new_key = list.prefix + new_item;
- let old_key = list.prefix + old_item;
- let items = list_items(list);
- let index = items.indexOf(old_item);
- items[index] = new_item;
- await setn([old_key, undefined, new_key, new_val, "_" + list.name, items]);
-
- list.map.delete(old_item);
-
- let change = {
- prefix : list.prefix,
- item : old_item,
- old_val,
- new_val : undefined
- };
-
- broadcast_change(change, list);
-
- list.map.set(new_item, new_val);
-
- change.item = new_item;
- change.old_val = undefined;
- change.new_val = new_val;
-
- broadcast_change(change, list);
-
- return old_val;
-}
-
-/*
- * For scripts, item name is chosen by user, data should be an object containing
- * - script's url and hash or
- * - script's text or
- * - all three
- */
-
-/*
- * For bundles, item name is chosen by user, data is an array of 2-element
- * arrays with type prefix and script/bundle names.
- */
-
-/* For pages data argument is same as for bundles. Item name is url. */
-
-exports.set = async function (prefix, item, data)
-{
- return set_item(item, data, list_by_prefix[prefix]);
-}
-
-exports.get = function (prefix, item)
-{
- return list_by_prefix[prefix].map.get(item);
-}
-
-exports.remove = async function (prefix, item)
-{
- return remove_item(item, list_by_prefix[prefix]);
-}
-
-exports.replace = async function (prefix, old_item, new_item,
- new_data=undefined)
-{
- return replace_item(old_item, new_item, list_by_prefix[prefix], new_data);
-}
-
-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]);
-}
-
-/* Finally, a quick way to wipe all the data. */
-// TODO: maybe delete items in such order that none of them ever references
-// an already-deleted one?
-exports.clear = async function ()
-{
- let lists = list_prefixes.map((p) => list_by_prefix[p]);
-
- for (let list of lists)
- await lock(list.lock);
-
- for (let list of lists) {
-
- let change = {
- prefix : list.prefix,
- new_val : undefined
- };
-
- for (let [item, val] of list_entries_it(list)) {
- change.item = item;
- change.old_val = val;
- broadcast_change(change, list);
- }
-
- list.map = new Map();
- }
-
- await browser.storage.local.clear();
-
- for (let list of lists)
- unlock(list.lock);
-}
-
-export default make_once(init);