From 329d0caac1124b8bab2d08f606eb9dc41e0a49b5 Mon Sep 17 00:00:00 2001
From: tophf <tophf@gmx.com>
Date: Wed, 23 Feb 2022 09:07:30 +0300
Subject: [PATCH] avoid flicker/delay when opening manager

---
 background/background.js |  1 +
 background/db.js         | 19 ++++++++++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/background/background.js b/background/background.js
index c3880247..c2fc7898 100644
--- a/background/background.js
+++ b/background/background.js
@@ -119,6 +119,7 @@ addAPI(/** @namespace API */ {
       }
       return tab;
     }
+    API.prefsDb.get('badFavs'); // prime the cache to avoid flicker/delay when opening the page
     return openURL({url, ignoreExisting: true}).then(activateTab); // activateTab unminimizes the window
   },
 
diff --git a/background/db.js b/background/db.js
index c14e8796..f674723a 100644
--- a/background/db.js
+++ b/background/db.js
@@ -1,6 +1,7 @@
 /* global addAPI */// common.js
 /* global chromeLocal */// storage-util.js
 /* global cloneError */// worker-util.js
+/* global deepCopy */// toolbox.js
 /* global prefs */
 'use strict';
 
@@ -20,9 +21,12 @@ const db = (() => {
   const FALLBACK = 'dbInChromeStorage';
   const ID_AS_KEY = {[DB]: true};
   const getStoreName = dbName => dbName === DB ? 'styles' : 'data';
+  const cache = {};
   const proxies = {};
   const proxyHandler = {
-    get: ({dbName}, cmd) => (...args) => exec(dbName, cmd, ...args),
+    get: ({dbName}, cmd) =>
+      (...args) =>
+        (dbName === DB ? exec : cachedExec)(dbName, cmd, ...args),
   };
   /**
    * @param {string} dbName
@@ -43,6 +47,19 @@ const db = (() => {
     styles: getProxy(DB, true),
   };
 
+  async function cachedExec(dbName, cmd, a, b) {
+    const hub = cache[dbName] || (cache[dbName] = {});
+    const res = cmd === 'get' && a in hub ? hub[a] : await exec(...arguments);
+    if (cmd === 'get') {
+      hub[a] = deepCopy(res);
+    } else if (cmd === 'put') {
+      hub[ID_AS_KEY[dbName] ? a.id : b] = deepCopy(a);
+    } else if (cmd === 'delete') {
+      delete hub[a];
+    }
+    return res;
+  }
+
   async function tryUsingIndexedDB() {
     // we use chrome.storage.local fallback if IndexedDB doesn't save data,
     // which, once detected on the first run, is remembered in chrome.storage.local