1 files changed, 143 insertions, 0 deletions
diff --git a/data/extensions/jsr@javascriptrestrictor/nscl/common/CachedStorage.js b/data/extensions/jsr@javascriptrestrictor/nscl/common/CachedStorage.js
new file mode 100644
index 0000000..6b1a727
--- /dev/null
+++ b/data/extensions/jsr@javascriptrestrictor/nscl/common/CachedStorage.js
@@ -0,0 +1,143 @@
+/*
+ * NoScript Commons Library
+ * Reusable building blocks for cross-browser security/privacy WebExtensions.
+ * Copyright (C) 2020-2024 Giorgio Maone <https://maone.net>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+var CachedStorage = (() => {
+  const scopes = new WeakMap();
+
+  const DEFER_DELAY = 1000;
+  let deferredTasks = null;
+  const performTasks = async () => {
+    for (let t of deferredTasks) t();
+    deferredTasks = null;
+  };
+  const deferTasks = (...tasks) => {
+    if (!deferredTasks) {
+      deferredTasks = tasks;
+      setTimeout(performTasks, DEFER_DELAY);
+    } else {
+      deferredTasks.push(...tasks);
+    }
+  };
+
+  const addNameSpace = (nameSpace, properties, keys) => {
+    const prefix = nameSpace ? `${nameSpace}.` : "";
+    const nameSpacedProps = {};
+    for (const key of keys) {
+      nameSpacedProps[`${prefix}${key}`] = properties[key];
+    }
+    return nameSpacedProps;
+  };
+  const removeNameSpace = (nameSpace, properties) => {
+    if (!nameSpace) return properties;
+    const len = nameSpace.length + 1;
+    const props = {};
+    for (const [key, val] of Object.entries(properties)) {
+      props[key.substring(len)] = val;
+    }
+    return props;
+  };
+
+  return {
+    async init(
+      properties = null,
+      nameSpace = "",
+      scope = null,
+      storageType = "session"
+    ) {
+      if (!properties) {
+        console.warn("CachedStorage.init(): no properties!");
+        return null;
+      }
+
+      scope ??= (nameSpace && globalThis[nameSpace]) || globalThis;
+
+      for (let p in properties) {
+        if (p in scope) {
+          // already initialized
+          return scope;
+        }
+        break;
+      }
+
+      if (!(storageType in browser.storage)) {
+        console.warn(
+          `CachedStorage.init(): no browser.storage.${storageType}, falling back to vanilla properties`
+        );
+        return Object.assign(scope, properties);
+      }
+
+      const keys = Object.keys(properties);
+      if (nameSpace) {
+        properties = addNameSpace(nameSpace, properties, keys);
+      } else {
+        nameSpace = "";
+      }
+
+      let metadata = scopes.get(scope);
+      if (!metadata) {
+        scopes.set(scope, (metadata = { storage: {} }));
+      }
+
+      const ns = (metadata.storage[storageType] ??= new Map()).get(nameSpace);
+      if (ns) {
+        for (const key of keys) ns.add(key);
+      } else {
+        metadata.storage[storageType].set(nameSpace, new Set(keys));
+      }
+      return Object.assign(
+        scope,
+        removeNameSpace(
+          nameSpace,
+          await browser.storage[storageType].get(properties)
+        )
+      );
+    },
+    async save(scope = globalThis, defer = false) {
+      const metadata = scopes.get(scope);
+      if (!metadata) {
+        console.warn(
+          `CacheStorage.save(): metadata not found for scope ${scope}!`
+        );
+        return false;
+      }
+
+      if (metadata.deferredSave) return;
+      if ((defer ||= Date.now() - metadata.lastSaved < 20)) {
+        metadata.deferredSave = true;
+        return Promise.resolve(
+          deferTasks(() => {
+            metadata.deferredSave = false;
+            this.save(scope);
+          })
+        );
+      }
+
+      const savingTasks = [];
+      for (const [storageType, ns] of Object.entries(metadata.storage)) {
+        for (const [nameSpace, keys] of ns.entries()) {
+          const properties = addNameSpace(nameSpace, scope, keys);
+          savingTasks.push(browser.storage[storageType].set(properties));
+        }
+      }
+      metadata.lastSaved = Date.now();
+      return await Promise.allSettled(savingTasks);
+    },
+  };
+})();