feat(logs): parse log4j xml events in logs

Signed-off-by: Rachel Powers <508861+Ryex@users.noreply.github.com>

launcher/logs/LogParser.h

@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  Prism Launcher - Minecraft Launcher
+ *  Copyright (C) 2025 Rachel Powers <508861+Ryex@users.noreply.github.com>
+ *
+ *  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, version 3.
+ *
+ *  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 <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <QAnyStringView>
+#include <QDateTime>
+#include <QList>
+#include <QString>
+#include <QStringView>
+#include <QXmlStreamReader>
+#include <optional>
+#include <variant>
+#include "MessageLevel.h"
+
+class LogParser {
+   public:
+    struct LogEntry {
+        QString logger;
+        MessageLevel::Enum level;
+        QString levelText;
+        QDateTime timestamp;
+        QString thread;
+        QString message;
+    };
+    struct Partial {
+        QString data;
+    };
+    struct PlainText {
+        QString message;
+    };
+    struct Error {
+        QString errMessage;
+        QXmlStreamReader::Error error;
+    };
+
+    using ParsedItem = std::variant<LogEntry, PlainText, Partial>;
+
+   public:
+    LogParser() = default;
+
+    void appendLine(QAnyStringView data);
+    std::optional<ParsedItem> parseNext();
+    std::optional<QList<ParsedItem>> parseAvailable();
+    std::optional<Error> getError();
+
+   protected:
+    MessageLevel::Enum parseLogLevel(const QString& level);
+    std::optional<LogEntry> parseAttributes();
+    void setError();
+    void clearError();
+
+    std::optional<ParsedItem> parseLog4J();
+
+   private:
+    QString m_buffer;
+    QString m_partialData;
+    QXmlStreamReader m_parser;
+    std::optional<Error> m_error;
+};