urlfilter: Add FilterTree class

FilterTree is a class that holds filter rules, sorted by the domain they
are to be applied on. The rules are to follow FilterLeaf as interface.
- Add a hostlist rule format to FilterTree.
- Add a test for hostlist format.

1 files changed, 86 insertions, 0 deletions

diff --git a/lib/urlfilter/filtertree.cpp b/lib/urlfilter/filtertree.cpp
new file mode 100644
index 0000000..8844a76
--- /dev/null
+++ b/lib/urlfilter/filtertree.cpp
@@ -0,0 +1,86 @@
+/*
+ * This file is part of smolbote. It's copyrighted by the contributors recorded
+ * in the version control history of the file, available from its original
+ * location: https://neueland.iserlohn-fortress.net/gitea/aqua/smolbote
+ *
+ * SPDX-License-Identifier: GPL-3.0
+ */
+
+#include "filtertree.h"
+#include "filterleaf.h"
+#include <QTextStream>
+#include "formats/hostlistrule.h"
+
+bool loadHostlist(QIODevice &from, FilterTree* tree)
+{
+    Q_ASSERT(from.isReadable());
+    QTextStream stream(&from);
+    while(!stream.atEnd()) {
+        const QString line = stream.readLine().trimmed();
+        if(line.isEmpty() || line.startsWith(QLatin1Literal("#")))
+            continue;
+
+        const QStringList &parts = line.split(QLatin1Literal(" "));
+        if(parts.length() < 2) {
+#ifdef QT_DEBUG
+            qDebug("Cannot parse: %s", qUtf8Printable(line));
+#endif
+            return false;
+        }
+
+        for(int i = 1; i < parts.length(); ++i) {
+            // HostlistRule(domain, redirect)
+            auto *rule = new HostlistRule(parts.at(i), parts.constFirst());
+            // addRule(rule, enable_on_domain)
+            const bool added = tree->addRule(rule, QString());
+            if(!added)
+                return false;
+        }
+
+    }
+    return true;
+}
+
+const QStringList FilterTree::branches() const
+{
+    QStringList branches;
+    for(auto &branch : m_branches) {
+        branches.append(QString::fromStdString(branch.domain));
+    }
+    return branches;
+}
+
+QVector<const FilterLeaf *> FilterTree::match(const QString& domain, const QString& requestUrl) const
+{
+    QVector<const FilterLeaf *> leaves;
+    for(const auto &branch : m_branches) {
+        if(branch.domain == domain.toStdString()) {
+
+            for(const auto leaf : branch.leaves) {
+                if(leaf->match(requestUrl)) {
+                    leaves.append(leaf);
+                }
+            }
+
+        }
+    }
+    return leaves;
+}
+
+bool FilterTree::addRule(FilterLeaf *rule, const QString& domain)
+{
+    for(auto &branch : m_branches) {
+        if(branch.domain == domain.toStdString()) {
+            branch.leaves.emplace_back(rule);
+            return true;
+        }
+    }
+
+    // no branch was found
+    Branch branch;
+    branch.domain = domain.toStdString();
+    // TODO: for some reason, can't add rule here
+    //branch.leaves.emplace_back(rule);
+    m_branches.emplace_back(std::move(branch));
+    return this->addRule(rule, domain);
+}