From ef825245b979d7c225ed2baacc0569b986e8abfd Mon Sep 17 00:00:00 2001
From: Raymond Hill <rhill@raymondhill.net>
Date: Tue, 25 Apr 2023 22:14:15 -0400
Subject: [PATCH] Simplify lz4 instance management

---
 src/js/lz4.js | 34 +++++++++++-----------------------
 1 file changed, 11 insertions(+), 23 deletions(-)

diff --git a/src/js/lz4.js b/src/js/lz4.js
index 3c5bf3800..163ad5186 100644
--- a/src/js/lz4.js
+++ b/src/js/lz4.js
@@ -38,32 +38,21 @@ import µb from './background.js';
 
 /******************************************************************************/
 
-let lz4CodecInstance;
-let pendingInitialization;
+let promisedInstance;
 let textEncoder, textDecoder;
 let ttlCount = 0;
 let ttlDelay = 60000;
 
 const init = function() {
     ttlDelay = µb.hiddenSettings.autoUpdateAssetFetchPeriod * 1000 + 15000;
-    if ( lz4CodecInstance === null ) {
-        return Promise.resolve(null);
-    }
-    if ( lz4CodecInstance !== undefined ) {
-        return Promise.resolve(lz4CodecInstance);
-    }
-    if ( pendingInitialization === undefined ) {
+    if ( promisedInstance === undefined ) {
         let flavor;
         if ( µb.hiddenSettings.disableWebAssembly === true ) {
             flavor = 'js';
         }
-        pendingInitialization = lz4BlockCodec.createInstance(flavor)
-            .then(instance => {
-                lz4CodecInstance = instance;
-                pendingInitialization = undefined;
-            });
+        promisedInstance = lz4BlockCodec.createInstance(flavor);
     }
-    return pendingInitialization;
+    return promisedInstance;
 };
 
 // We can't shrink memory usage of lz4 codec instances, and in the
@@ -80,7 +69,7 @@ const destroy = function() {
     //        lz4CodecInstance.bytesInUse() >>> 10
     //    );
     //}
-    lz4CodecInstance = undefined;
+    promisedInstance = undefined;
     textEncoder = textDecoder = undefined;
     ttlCount = 0;
 };
@@ -91,11 +80,10 @@ const ttlManage = function(count) {
     ttlTimer.off();
     ttlCount += count;
     if ( ttlCount > 0 ) { return; }
-    if ( lz4CodecInstance === undefined ) { return; }
     ttlTimer.on(ttlDelay);
 };
 
-const encodeValue = function(dataIn) {
+const encodeValue = function(lz4CodecInstance, dataIn) {
     if ( !lz4CodecInstance ) { return; }
     //let t0 = window.performance.now();
     if ( textEncoder === undefined ) {
@@ -123,7 +111,7 @@ const encodeValue = function(dataIn) {
     return outputArray;
 };
 
-const decodeValue = function(inputArray) {
+const decodeValue = function(lz4CodecInstance, inputArray) {
     if ( !lz4CodecInstance ) { return; }
     //let t0 = window.performance.now();
     if (
@@ -163,8 +151,8 @@ const lz4Codec = {
             return dataIn;
         }
         ttlManage(1);
-        await init();
-        let dataOut = encodeValue(dataIn);
+        const lz4CodecInstance = await init();
+        let dataOut = encodeValue(lz4CodecInstance, dataIn);
         ttlManage(-1);
         if ( serialize instanceof Function ) {
             dataOut = await serialize(dataOut);
@@ -184,8 +172,8 @@ const lz4Codec = {
             return dataIn;
         }
         ttlManage(1);
-        await init();
-        const dataOut = decodeValue(dataIn);
+        const lz4CodecInstance = await init();
+        const dataOut = decodeValue(lz4CodecInstance, dataIn);
         ttlManage(-1);
         return dataOut || dataIn;
     },