From e2b1cc628b304e3f153abc17fb350aa781e26b36 Mon Sep 17 00:00:00 2001
From: Aqua-sama <aqua@iserlohn-fortress.net>
Date: Mon, 18 Dec 2017 14:32:45 +0100
Subject: Basic adblock FilterRule

---
 lib/adblock/filterrule.cpp | 102 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 lib/adblock/filterrule.cpp

(limited to 'lib/adblock/filterrule.cpp')

diff --git a/lib/adblock/filterrule.cpp b/lib/adblock/filterrule.cpp
new file mode 100644
index 0000000..147e5fd
--- /dev/null
+++ b/lib/adblock/filterrule.cpp
@@ -0,0 +1,102 @@
+/*******************************************************************************
+ **
+ ** smolbote: yet another qute browser
+ ** Copyright (C) 2017  Xian Nox
+ **
+ ** This program is free software: you can redistribute it and/or modify
+ ** it under the terms of the GNU General Public License as published by
+ ** the Free Software Foundation, either version 3 of the License, or
+ ** (at your option) any later version.
+ **
+ ** This program is distributed in the hope that it will be useful,
+ ** but WITHOUT ANY WARRANTY; without even the implied warranty of
+ ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ ** GNU General Public License for more details.
+ **
+ ** You should have received a copy of the GNU General Public License
+ ** along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ **
+ ******************************************************************************/
+
+#include "filterrule.h"
+#include <QUrl>
+
+/* TODO
+ * - split this class into two: FilterRule that only deals with matching, and AdBlockRule, which only deals with parsing
+ */
+
+/* The AdBlock standard is an incredible mess, vaguely explaiend on:
+ * - https://adblockplus.org/filters
+ * - https://adblockplus.org/filter-cheatsheet
+ */
+
+FilterRule::FilterRule(const QString &line)
+{
+    valid = parse(line);
+}
+
+FilterRule::~FilterRule()
+{
+}
+
+bool FilterRule::isValid() const
+{
+    return valid;
+}
+
+bool FilterRule::isException() const
+{
+    return exception;
+}
+
+bool FilterRule::shouldBlock(const QUrl &requestUrl) const
+{
+    QRegularExpressionMatch match = rule.match(requestUrl.toString());
+    return match.hasMatch();
+}
+
+bool FilterRule::parse(const QString &line)
+{
+    // skip for comments and empty rules
+    if(line.startsWith('!') || line.trimmed().isEmpty()) {
+        return false;
+    }
+
+    // make a copy of the pattern so we can snap off the parts we've already parsed
+    QString pattern = line;
+
+    if(pattern.startsWith("@@")) {
+        exception = true;
+        pattern = pattern.mid(2);   // remove @@
+    }
+
+    rule.setPattern(createRegExpPattern(pattern));
+    return true;
+}
+
+QString createRegExpPattern(const QString &line)
+{
+    QString pattern = line;
+
+    // replace . (any character) with \. (a dot)
+    pattern.replace('.', "\\.");
+
+    // translate adblock special characters into regex
+    // replace wildcard (*) with '.*' (zero or more of any element)
+    pattern.replace('*', ".*");
+
+    // replace separator (^) with '($|\?|\/)' (end of string, or ?, or /, or :number)
+    pattern.replace('^', "($|\\?|\\/|:\\d+)");
+
+    // replace || with ^\w+://([\w,\d,\.]+)?
+    pattern.replace("||", "^\\w+://([\\w,\\d,\\.]+)?");
+
+    if(pattern.startsWith('|') && pattern.endsWith('|')) {
+        // replace | at start with ^ (start of string)
+        pattern.replace(0, 1, '^');
+        // replace | at end with $ (end of string)
+        pattern.replace('|', '$');
+    }
+
+    return pattern;
+}
-- 
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