From eb8ae20cc159a3db45b464e6eb0ebcd9a19b3e93 Mon Sep 17 00:00:00 2001
From: David Rosca <nowrep@gmail.com>
Date: Sun, 13 Apr 2014 11:49:39 +0200
Subject: [PATCH] [AdBlockRule] Improve performance of rule matching with
 QStringMatcher

Use QStringMatcher instead of QString::contains in RegExpFilters.
QStringMatcher internally uses fast Boyer-Moore algorithm.
---
 src/lib/adblock/adblockrule.cpp | 21 ++++++++++++++++-----
 src/lib/adblock/adblockrule.h   |  5 +++--
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/lib/adblock/adblockrule.cpp b/src/lib/adblock/adblockrule.cpp
index d777ca4f3..eee3a2d0d 100644
--- a/src/lib/adblock/adblockrule.cpp
+++ b/src/lib/adblock/adblockrule.cpp
@@ -468,7 +468,7 @@ void AdBlockRule::parseFilter()
         m_type = RegExpMatchRule;
         m_regExp = new RegExp;
         m_regExp->regExp = QzRegExp(parsedLine, m_caseSensitivity);
-        m_regExp->regExpStrings = parseRegExpFilter(parsedLine);
+        m_regExp->matchers = createStringMatchers(parseRegExpFilter(parsedLine));
         return;
     }
 
@@ -509,7 +509,7 @@ void AdBlockRule::parseFilter()
         m_type = RegExpMatchRule;
         m_regExp = new RegExp;
         m_regExp->regExp = QzRegExp(createRegExpFromFilter(parsedLine), m_caseSensitivity);
-        m_regExp->regExpStrings = parseRegExpFilter(parsedLine);
+        m_regExp->matchers = createStringMatchers(parseRegExpFilter(parsedLine));
         return;
     }
 
@@ -632,6 +632,18 @@ QString AdBlockRule::createRegExpFromFilter(const QString &filter) const
     return parsed;
 }
 
+QList<QStringMatcher> AdBlockRule::createStringMatchers(const QStringList &filters) const
+{
+    QList<QStringMatcher> matchers;
+    matchers.reserve(filters.size());
+
+    foreach (const QString &filter, filters) {
+        matchers.append(QStringMatcher(filter, m_caseSensitivity));
+    }
+
+    return matchers;
+}
+
 bool AdBlockRule::isMatchingDomain(const QString &domain, const QString &filter) const
 {
     return QzTools::matchDomain(filter, domain);
@@ -641,10 +653,9 @@ bool AdBlockRule::isMatchingRegExpStrings(const QString &url) const
 {
     Q_ASSERT(m_regExp);
 
-    foreach (const QString &string, m_regExp->regExpStrings) {
-        if (!url.contains(string)) {
+    foreach (const QStringMatcher &matcher, m_regExp->matchers) {
+        if (matcher.indexIn(url) == -1)
             return false;
-        }
     }
 
     return true;
diff --git a/src/lib/adblock/adblockrule.h b/src/lib/adblock/adblockrule.h
index cb7e46557..a624a72c2 100644
--- a/src/lib/adblock/adblockrule.h
+++ b/src/lib/adblock/adblockrule.h
@@ -47,7 +47,7 @@
 #define ADBLOCKRULE_H
 
 #include <QObject>
-#include <QStringList>
+#include <QStringMatcher>
 
 #include "qzcommon.h"
 #include "qzregexp.h"
@@ -136,6 +136,7 @@ private:
     bool filterIsOnlyDomain(const QString &filter) const;
     bool filterIsOnlyEndsMatch(const QString &filter) const;
     QString createRegExpFromFilter(const QString &filter) const;
+    QList<QStringMatcher> createStringMatchers(const QStringList &filters) const;
 
     AdBlockSubscription* m_subscription;
 
@@ -159,7 +160,7 @@ private:
 
     struct RegExp {
         QzRegExp regExp;
-        QStringList regExpStrings;
+        QList<QStringMatcher> matchers;
     };
 
     // Use dynamic allocation to save memory