switch to qdcss for parsing

make it not horrible to look at

Signed-off-by: kumquat-ir <66188216+kumquat-ir@users.noreply.github.com>

libraries/README.md

@@ -140,3 +140,11 @@ A TOML language parser. Used by Forge 1.14+ to store mod metadata.
 See [github repo](https://github.com/marzer/tomlplusplus).
 
 Licenced under the MIT licence.
+
+## qdcss
+
+A quick and dirty css parser, used by NilLoader to store mod metadata.
+
+Translated (and heavily trimmed down) from [the original Java code](https://github.com/unascribed/NilLoader/blob/trunk/src/main/java/nilloader/api/lib/qdcss/QDCSS.java) from NilLoader
+
+Licensed under LGPL version 3.

libraries/qdcss/CMakeLists.txt

@@ -0,0 +1,18 @@
+cmake_minimum_required(VERSION 3.9.4)
+project(qdcss)
+
+if(QT_VERSION_MAJOR EQUAL 5)
+    find_package(Qt5 COMPONENTS Core REQUIRED)
+elseif(Launcher_QT_VERSION_MAJOR EQUAL 6)
+    find_package(Qt6 COMPONENTS Core Core5Compat REQUIRED)
+    list(APPEND qdcss_LIBS Qt${QT_VERSION_MAJOR}::Core5Compat)
+endif()
+
+set(QDCSS_SOURCES
+    include/qdcss.h
+    src/qdcss.cpp
+)
+
+add_library(qdcss STATIC ${QDCSS_SOURCES})
+target_include_directories(qdcss PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
+target_link_libraries(qdcss Qt${QT_VERSION_MAJOR}::Core ${qdcss_LIBS})

libraries/qdcss/include/qdcss.h

@@ -0,0 +1,21 @@
+#ifndef QDCSS_H
+#define QDCSS_H
+
+#include <QMap>
+#include <QString>
+#include <QStringList>
+#include <optional>
+
+class QDCSS {
+    // these are all we need to parse a couple string values out of a css string
+    // lots more in the original code, yet to be ported
+    // https://github.com/unascribed/NilLoader/blob/trunk/src/main/java/nilloader/api/lib/qdcss/QDCSS.java
+   public:
+    QDCSS(QString);
+    std::optional<QString>* get(QString);
+
+   private:
+    QMap<QString, QStringList> m_data;
+};
+
+#endif  // QDCSS_H

libraries/qdcss/src/qdcss.cpp

@@ -0,0 +1,49 @@
+#include "qdcss.h"
+
+#include <QRegularExpression>
+#include <QRegularExpressionMatch>
+#include <QRegularExpressionMatchIterator>
+
+QRegularExpression ruleset_re = QRegularExpression(R"([#.]?(@?\w+?)\s*\{(.*?)\})", QRegularExpression::DotMatchesEverythingOption);
+QRegularExpression rule_re = QRegularExpression(R"((\S+?)\s*:\s*(?:\"(.*?)(?<!\\)\"|'(.*?)(?<!\\)'|(\S+?))\s*(?:;|$))");
+
+QDCSS::QDCSS(QString s)
+{
+    // not much error handling over here...
+    // the original java code used indeces returned by the matcher for them, but QRE does not expose those
+    QRegularExpressionMatchIterator ruleset_i = ruleset_re.globalMatch(s);
+    while (ruleset_i.hasNext()) {
+        QRegularExpressionMatch ruleset = ruleset_i.next();
+        QString selector = ruleset.captured(1);
+        QString rules = ruleset.captured(2);
+        QRegularExpressionMatchIterator rule_i = rule_re.globalMatch(rules);
+        while (rule_i.hasNext()) {
+            QRegularExpressionMatch rule = rule_i.next();
+            QString property = rule.captured(1);
+            QString value;
+            if (!rule.captured(2).isNull()) {
+                value = rule.captured(2);
+            } else if (!rule.captured(3).isNull()) {
+                value = rule.captured(3);
+            } else {
+                value = rule.captured(4);
+            }
+            QString key = selector + "." + property;
+            if (!m_data.contains(key)) {
+                m_data.insert(key, QStringList());
+            }
+            m_data.find(key)->append(value);
+        }
+    }
+}
+
+std::optional<QString>* QDCSS::get(QString key)
+{
+    auto found = m_data.find(key);
+
+    if (found == m_data.end() || found->empty()) {
+        return new std::optional<QString>;
+    }
+
+    return new std::optional<QString>(found->back());
+}