1 files changed, 110 insertions, 0 deletions
diff --git a/src/main/java/moe/nea/modernjava/launch/relaunch/FCPRelauncher.java b/src/main/java/moe/nea/modernjava/launch/relaunch/FCPRelauncher.java
new file mode 100644
index 0000000..04fb0ea
--- /dev/null
+++ b/src/main/java/moe/nea/modernjava/launch/relaunch/FCPRelauncher.java
@@ -0,0 +1,110 @@
+package moe.nea.modernjava.launch.relaunch;
+
+import moe.nea.modernjava.launch.util.PropertyNames;
+import moe.nea.modernjava.launch.util.TextIoUtils;
+import moe.nea.modernjava.launch.util.WellKnownBlackboard;
+import net.minecraftforge.fml.common.launcher.FMLTweaker;
+import net.minecraftforge.fml.nea.moe.modernjava.IAMFML;
+
+import java.io.File;
+import java.io.IOException;
+import java.lang.management.ManagementFactory;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+public class FCPRelauncher {
+
+    /**
+     * @return the original arguments, as passed to the main method.
+     */
+    public static List<String> getOriginalArguments() {
+        List<String> originalArgs = new ArrayList<>();
+
+        // Provided by FML
+        // This is highly processed so there might be some arguments that become lost, but almost everything should be in here.
+        // Namely non -- arguments get lost. I don't know any of these arguments that the vanilla launcher uses, so it should be fine?
+        // Also, some tweakers are missing. But we can fix this.
+        Map<String, String> launchArgs = WellKnownBlackboard.launchArgs();
+        if ("UnknownFMLProfile".equals(launchArgs.get("--version"))) {
+            launchArgs.remove("--version");
+        }
+        for (Map.Entry<String, String> argument : launchArgs.entrySet()) {
+            originalArgs.add(argument.getKey());
+            originalArgs.add(argument.getValue());
+        }
+
+
+        originalArgs.add("--tweakClass");
+        originalArgs.add(FMLTweaker.class.getName());
+        System.out.println("Reconstructed original minecraft arguments: " + originalArgs);
+        return originalArgs;
+    }
+
+    public static File findJavaLauncher() {
+        return new File("/home/nea/.sdkman/candidates/java/16.0.2-tem/bin/java")
+    }
+
+    public static void relaunch() {
+
+        List<String> originalArgs = getOriginalArguments();
+
+        File modernJavaPath = findJavaLauncher();
+
+
+        File agentFile;
+        agentFile = new File("/home/nea/src/ModernJavaLauncher/target/build/libs/target.jar");
+
+        System.out.println("Located modern minecraft at: " + modernJavaPath);
+
+        ProcessBuilder processBuilder = new ProcessBuilder();
+        processBuilder.inheritIO();
+        processBuilder.directory(null);
+
+
+        List<String> moduleOpens = new ArrayList<>();
+        moduleOpens.add("java.base/java.util=ALL-UNNAMED");
+        moduleOpens.add("java.base/jdk.internal.loader=ALL-UNNAMED");
+        moduleOpens.add("java.base/java.lang.reflect=ALL-UNNAMED");
+
+
+        List<String> fullCommandLine = new ArrayList<>();
+        fullCommandLine.add(modernJavaPath.getAbsolutePath());
+        fullCommandLine.addAll(ManagementFactory.getRuntimeMXBean().getInputArguments());
+        fullCommandLine.add("-D" + PropertyNames.HAS_RELAUNCHED + "=true");
+        fullCommandLine.add("-D" + PropertyNames.RELAUNCH_CLASSPATH + "=" + agentFile.getAbsolutePath() + File.pathSeparator + ManagementFactory.getRuntimeMXBean().getClassPath());
+        fullCommandLine.add("--illegal-access=permit");
+        for (String open : moduleOpens) {
+            fullCommandLine.add("--add-opens");
+            fullCommandLine.add(open);
+        }
+        if (System.getProperty(PropertyNames.DEBUG_PORT) != null)
+            fullCommandLine.add("-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=*:" + System.getProperty(PropertyNames.DEBUG_PORT));
+        fullCommandLine.add("-javaagent:" + agentFile);
+        fullCommandLine.add("--add-modules=ALL-MODULE-PATH,ALL-SYSTEM,ALL-DEFAULT,java.sql");
+        fullCommandLine.add("-Xbootclasspath/a:" + agentFile);
+        fullCommandLine.add("moe.nea.modernjava.target.RelaunchEntryPoint");
+        fullCommandLine.addAll(originalArgs);
+
+        System.out.println("Full relaunch commandline: " + fullCommandLine);
+
+
+        processBuilder.command(fullCommandLine);
+        int exitCode;
+        try {
+            try {
+                Process process = processBuilder.start();
+                exitCode = process.waitFor();
+            } finally {
+                TextIoUtils.flushStdIO();
+            }
+        } catch (IOException | InterruptedException e) {
+            throw new RuntimeException("Failed to relaunch with old java version", e);
+        }
+
+
+        System.out.println("Exiting outer relaunch layer");
+        IAMFML.shutdown(exitCode);
+    }
+
+}