From 7f368d46ea06164da025c1ac4ed9a65ad23b25ef Mon Sep 17 00:00:00 2001
From: Wojtek Kosior <wk@koszkonutek-tmp.pl.eu.org>
Date: Wed, 12 May 2021 16:00:09 +0200
Subject: stop using js modules

---
 background/reverse_use_info.js | 96 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 background/reverse_use_info.js

(limited to 'background/reverse_use_info.js')

diff --git a/background/reverse_use_info.js b/background/reverse_use_info.js
new file mode 100644
index 0000000..3399285
--- /dev/null
+++ b/background/reverse_use_info.js
@@ -0,0 +1,96 @@
+/**
+* Myext scripts and bundles usage index
+*
+* Copyright (C) 2021 Wojtek Kosior
+*
+* Dual-licensed under:
+*   - 0BSD license
+*   - GPLv3 or (at your option) any later version
+*/
+
+"use strict";
+
+/*
+ * We want to count referenes to scripts and bundles in order to know,
+ * for example, whether one can be safely deleted.
+ */
+
+(() => {
+    const TYPE_PREFIX = window.TYPE_PREFIX;
+    const get_storage = window.get_storage;
+    const make_once = window.make_once;
+
+    var component_uses = new Map();
+    var storage;
+
+    function add_use_info_by_item(prefix, item, components)
+    {
+	for (let component of components) {
+	    component = component.join("");
+
+	    let used_by_info = component_uses.get(component);
+
+	    if (used_by_info === undefined) {
+		used_by_info = {};
+		component_uses.set(component, used_by_info);
+	    }
+
+	    if (used_by_info[prefix] === undefined)
+		used_by_info[prefix] = new Set();
+
+	    used_by_info[prefix].add(item);
+	}
+    }
+
+    function remove_use_info_by_item(prefix, item, components)
+    {
+	for (let component of components) {
+	    used_by_info = component_uses.get(component.join(""));
+	    if (used_by_info === undefined ||
+		used_by_info[prefix] === undefined)
+		return;
+
+	    used_by_info[prefix].delete(item);
+	}
+    }
+
+    function build_reverse_uses_info(entries_it, type_prefix)
+    {
+	for (let [item, components] of storage.get_all_it(type_prefix))
+	    add_use_info_by_item(type_prefix, item, components);
+    }
+
+    function handle_change(change)
+    {
+	if (change.old_val !== undefined)
+	    remove_use_info_by_item(change.prefix, change.item, change.old_val);
+
+	if (change.new_val !== undefined)
+	    add_use_info_by_item(change.prefix, change.item, change.new_val);
+    }
+
+    function get_uses(arg1, arg2=undefined)
+    {
+	let [prefix, item] = [arg1, arg2];
+
+	if (arg2 === undefined)
+	    [prefix, item] = arg1;
+
+	return component_uses.get(prefix + item);
+    }
+
+    async function init()
+    {
+	storage = await get_storage();
+
+	prefixes = [TYPE_PREFIX.PAGE, TYPE_PREFIX.BUNDLE];
+	for (let prefix of prefixes)
+	    build_reverse_uses_info(prefix);
+
+	storage.add_change_listener(handle_change, prefixes);
+
+	return get_uses;
+    }
+
+    window.get_reverse_use_info = make_once(init);
+})();
-- 
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