Cache program preferences

So that qbt can just use the data from memory which is vastly faster than waiting for a response
over the net.

src/webui/www/private/scripts/cache.js

@@ -0,0 +1,112 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2024  Mike Tzou (Chocobo1)
+ *
+ * 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 2
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * In addition, as a special exception, the copyright holders give permission to
+ * link this program with the OpenSSL project's "OpenSSL" library (or with
+ * modified versions of it that use the same license as the "OpenSSL" library),
+ * and distribute the linked executables. You must obey the GNU General Public
+ * License in all respects for all of the code used other than "OpenSSL".  If you
+ * modify file(s), 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.
+ */
+
+'use strict';
+
+if (window.qBittorrent === undefined)
+    window.qBittorrent = {};
+
+window.qBittorrent.Cache = (() => {
+    const exports = () => {
+        return {
+            preferences: new PreferencesCache()
+        };
+    };
+
+    class PreferencesCache {
+        #m_store = {};
+
+        // obj: {
+        //   onFailure: () => {},
+        //   onSuccess: () => {}
+        // }
+        init(obj = {}) {
+            new Request.JSON({
+                url: 'api/v2/app/preferences',
+                method: 'get',
+                noCache: true,
+                onFailure: (xhr) => {
+                    if (typeof obj.onFailure === 'function')
+                        obj.onFailure(xhr);
+                },
+                onSuccess: (responseJSON, responseText) => {
+                    if (!responseJSON)
+                        return;
+                    this.#m_store = structuredClone(responseJSON);
+
+                    if (typeof obj.onSuccess === 'function')
+                        obj.onSuccess(responseJSON, responseText);
+                }
+            }).send();
+        }
+
+        get() {
+            return structuredClone(this.#m_store);
+        }
+
+        // obj: {
+        //   data: {},
+        //   onFailure: () => {},
+        //   onSuccess: () => {}
+        // }
+        set(obj) {
+            if (typeof obj !== 'object')
+                throw new Error('`obj` is not an object.');
+            if (typeof obj.data !== 'object')
+                throw new Error('`data` is not an object.');
+
+            new Request({
+                url: 'api/v2/app/setPreferences',
+                method: 'post',
+                data: {
+                    'json': JSON.stringify(obj.data)
+                },
+                onFailure: (xhr) => {
+                    if (typeof obj.onFailure === 'function')
+                        obj.onFailure(xhr);
+                },
+                onSuccess: (responseText, responseXML) => {
+                    for (const key in obj.data) {
+                        if (!Object.hasOwn(obj.data, key))
+                            continue;
+
+                        const value = obj.data[key];
+                        this.#m_store[key] = value;
+                    }
+
+                    if (typeof obj.onSuccess === 'function')
+                        obj.onSuccess(responseText, responseXML);
+                }
+            }).send();
+        }
+    }
+
+    return exports();
+})();
+
+Object.freeze(window.qBittorrent.Cache);