From 34a138e3efe9506e3ea4e8462b7c5280e3e28b6c Mon Sep 17 00:00:00 2001
From: Raymond Hill <rhill@raymondhill.net>
Date: Sun, 17 Mar 2019 09:45:28 -0400
Subject: [PATCH] Add `unlimitedStorage` to Firefox manifest; add timeout to
 IndexedDB access

Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/416

The Chromium version of uBO has declared `unlimitedStorage` since the
extension was first published in 2014. Declaring this permission in
Firefox brings uBO inline with the Chromium version. I suspect some
reported errors could be caused by IndexedDB eviction due to the lack
of `unlimitedStorage` permission.

Additionally, a timeout has been added when uBO tries to access its
indexedDB storage. It's unclear whether this will help with the
mentioned related issue though, the root cause is still to be
identified.
---
 platform/firefox/manifest.json |  1 +
 src/js/cachestorage.js         | 23 ++++++++++++++++++-----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/platform/firefox/manifest.json b/platform/firefox/manifest.json
index ace1bfca9..099030ffe 100644
--- a/platform/firefox/manifest.json
+++ b/platform/firefox/manifest.json
@@ -74,6 +74,7 @@
     "privacy",
     "storage",
     "tabs",
+    "unlimitedStorage",
     "webNavigation",
     "webRequest",
     "webRequestBlocking",
diff --git a/src/js/cachestorage.js b/src/js/cachestorage.js
index e2b51ba0c..317980813 100644
--- a/src/js/cachestorage.js
+++ b/src/js/cachestorage.js
@@ -226,19 +226,30 @@
                     table.createIndex('value', 'value', { unique: false });
                 };
                 req.onsuccess = function(ev) {
+                    if ( resolve === undefined ) { return; }
                     req = undefined;
                     db = ev.target.result;
                     db.onerror = db.onabort = genericErrorHandler;
                     dbPromise = undefined;
                     resolve(db);
+                    resolve = undefined;
                 };
                 req.onerror = req.onblocked = function() {
+                    if ( resolve === undefined ) { return; }
                     req = undefined;
                     console.log(this.error);
                     db = null;
                     dbPromise = undefined;
                     resolve(null);
+                    resolve = undefined;
                 };
+                setTimeout(( ) => {
+                    if ( resolve === undefined ) { return; }
+                    db = null;
+                    dbPromise = undefined;
+                    resolve(null);
+                    resolve = undefined;
+                }, 5000);
             });
             return dbPromise;
         };
@@ -246,8 +257,8 @@
         const getFromDb = function(keys, keyvalStore, callback) {
             if ( typeof callback !== 'function' ) { return; }
             if ( keys.length === 0 ) { return callback(keyvalStore); }
-            let promises = [];
-            let gotOne = function() {
+            const promises = [];
+            const gotOne = function() {
                 if ( typeof this.result !== 'object' ) { return; }
                 keyvalStore[this.result.key] = this.result.value;
                 if ( this.result.value instanceof Blob === false ) { return; }
@@ -262,7 +273,7 @@
             };
             getDb().then(db => {
                 if ( !db ) { return callback(); }
-                const transaction = db.transaction(STORAGE_NAME);
+                const transaction = db.transaction(STORAGE_NAME, 'readonly');
                 transaction.oncomplete =
                 transaction.onerror =
                 transaction.onabort = ( ) => {
@@ -272,11 +283,13 @@
                 };
                 const table = transaction.objectStore(STORAGE_NAME);
                 for ( const key of keys ) {
-                    let req = table.get(key);
+                    const req = table.get(key);
                     req.onsuccess = gotOne;
                     req.onerror = noopfn;
-                    req = undefined;
                 }
+            }).catch(reason => {
+                console.info(`cacheStorage.getFromDb() failed: ${reason}`);
+                callback();
             });
         };