From 1c26afe874001c024113ad6a9adf99fb347612a8 Mon Sep 17 00:00:00 2001
From: Raymond Hill <rhill@raymondhill.net>
Date: Wed, 20 Feb 2019 08:51:14 -0500
Subject: [PATCH] Remove caching the result of domain extraction from hostname

With the new PSL implementation, benchmarks do not show benefit
from caching the domain extracted from a hostname for later
reuse -- the caching seems to even add an overhead instead with
the new publicSuffixList implementation.
---
 src/js/redirect-engine.js      |  2 +-
 src/js/static-ext-filtering.js |  2 +-
 src/js/uritools.js             | 84 ----------------------------------
 3 files changed, 2 insertions(+), 86 deletions(-)

diff --git a/src/js/redirect-engine.js b/src/js/redirect-engine.js
index 419361216..15982c437 100644
--- a/src/js/redirect-engine.js
+++ b/src/js/redirect-engine.js
@@ -319,7 +319,7 @@ RedirectEngine.prototype.compileRuleFromStaticFilter = function(line) {
             continue;
         }
         if ( option === 'first-party' || option === '1p' ) {
-            srcs.push(µBlock.URI.domainFromHostnameNoCache(des) || des);
+            srcs.push(µBlock.URI.domainFromHostname(des) || des);
             continue;
         }
         // One and only one type must be specified.
diff --git a/src/js/static-ext-filtering.js b/src/js/static-ext-filtering.js
index 8b2f533ef..598d6bb01 100644
--- a/src/js/static-ext-filtering.js
+++ b/src/js/static-ext-filtering.js
@@ -615,7 +615,7 @@
             const pos = hostname.lastIndexOf('.', hostname.length - 3);
             domain = pos !== -1 ? hostname.slice(pos + 1) : hostname;
         } else {
-            domain = µb.URI.domainFromHostnameNoCache(hostname);
+            domain = µb.URI.domainFromHostname(hostname);
         }
         return api.makeHash(domain);
     };
diff --git a/src/js/uritools.js b/src/js/uritools.js
index 0bb59c8d0..dbc8c8590 100644
--- a/src/js/uritools.js
+++ b/src/js/uritools.js
@@ -286,18 +286,6 @@ URI.hostnameFromURI = function(uri) {
 /******************************************************************************/
 
 URI.domainFromHostname = function(hostname) {
-    let entry = domainCache.get(hostname);
-    if ( entry !== undefined ) {
-        entry.tstamp = Date.now();
-        return entry.domain;
-    }
-    if ( reIPAddressNaive.test(hostname) === false ) {
-        return domainCacheAdd(hostname, psl.getDomain(hostname));
-    }
-    return domainCacheAdd(hostname, hostname);
-};
-
-URI.domainFromHostnameNoCache = function(hostname) {
     return reIPAddressNaive.test(hostname) ? hostname : psl.getDomain(hostname);
 };
 
@@ -325,78 +313,6 @@ URI.pathFromURI = function(uri) {
 
 /******************************************************************************/
 
-// Trying to alleviate the worries of looking up too often the domain name from
-// a hostname. With a cache, uBlock benefits given that it deals with a
-// specific set of hostnames within a narrow time span -- in other words, I
-// believe probability of cache hit are high in uBlock.
-
-const domainCache = new Map();
-const domainCacheCountLowWaterMark = 40;
-const domainCacheCountHighWaterMark = 60;
-const domainCacheEntryJunkyardMax =
-    domainCacheCountHighWaterMark - domainCacheCountLowWaterMark;
-
-const DomainCacheEntry = function(domain) {
-    this.init(domain);
-};
-
-DomainCacheEntry.prototype = {
-    init: function(domain) {
-        this.domain = domain;
-        this.tstamp = Date.now();
-        return this;
-    },
-    dispose: function() {
-        this.domain = '';
-        if ( domainCacheEntryJunkyard.length < domainCacheEntryJunkyardMax ) {
-            domainCacheEntryJunkyard.push(this);
-        }
-    },
-};
-
-const domainCacheEntryFactory = function(domain) {
-    return domainCacheEntryJunkyard.length !== 0 ?
-        domainCacheEntryJunkyard.pop().init(domain) :
-        new DomainCacheEntry(domain);
-};
-
-const domainCacheEntryJunkyard = [];
-
-const domainCacheAdd = function(hostname, domain) {
-    const entry = domainCache.get(hostname);
-    if ( entry !== undefined ) {
-        entry.tstamp = Date.now();
-    } else {
-        domainCache.set(hostname, domainCacheEntryFactory(domain));
-        if ( domainCache.size === domainCacheCountHighWaterMark ) {
-            domainCachePrune();
-        }
-    }
-    return domain;
-};
-
-const domainCacheEntrySort = function(a, b) {
-    return domainCache.get(b).tstamp - domainCache.get(a).tstamp;
-};
-
-const domainCachePrune = function() {
-    const hostnames = Array.from(domainCache.keys())
-                           .sort(domainCacheEntrySort)
-                           .slice(domainCacheCountLowWaterMark);
-    let i = hostnames.length;
-    while ( i-- ) {
-        const hostname = hostnames[i];
-        domainCache.get(hostname).dispose();
-        domainCache.delete(hostname);
-    }
-};
-
-window.addEventListener('publicSuffixListChanged', function() {
-    domainCache.clear();
-});
-
-/******************************************************************************/
-
 URI.domainFromURI = function(uri) {
     if ( !uri ) {
         return '';