NOISSUE use classparser for importing Legacy instances with undecided Minecraft versions

libraries/classparser/src/classparser.cpp

@@ -0,0 +1,85 @@
+/* Copyright 2013-2017 MultiMC Contributors
+ *
+ * Authors: Orochimarufan <orochimarufan.x3@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "classfile.h"
+#include "classparser.h"
+
+#include <QFile>
+#include <quazipfile.h>
+#include <QDebug>
+
+namespace classparser
+{
+
+QString GetMinecraftJarVersion(QString jarName)
+{
+	QString version;
+
+	// check if minecraft.jar exists
+	QFile jar(jarName);
+	if (!jar.exists())
+		return version;
+
+	// open minecraft.jar
+	QuaZip zip(&jar);
+	if (!zip.open(QuaZip::mdUnzip))
+		return version;
+
+	// open Minecraft.class
+	zip.setCurrentFile("net/minecraft/client/Minecraft.class", QuaZip::csSensitive);
+	QuaZipFile Minecraft(&zip);
+	if (!Minecraft.open(QuaZipFile::ReadOnly))
+		return version;
+
+	// read Minecraft.class
+	qint64 size = Minecraft.size();
+	char *classfile = new char[size];
+	Minecraft.read(classfile, size);
+
+	// parse Minecraft.class
+	try
+	{
+		char *temp = classfile;
+		java::classfile MinecraftClass(temp, size);
+		java::constant_pool constants = MinecraftClass.constants;
+		for (java::constant_pool::container_type::const_iterator iter = constants.begin();
+			 iter != constants.end(); iter++)
+		{
+			const java::constant &constant = *iter;
+			if (constant.type != java::constant::j_string_data)
+				continue;
+			const std::string &str = constant.str_data;
+			qDebug() << QString::fromStdString(str);
+			if (str.compare(0, 20, "Minecraft Minecraft ") == 0)
+			{
+				version = str.substr(20).data();
+				break;
+			}
+		}
+	}
+	catch (java::classfile_exception &)
+	{
+	}
+
+	// clean up
+	delete[] classfile;
+	Minecraft.close();
+	zip.close();
+	jar.close();
+
+	return version;
+}
+}