v0.8.0: Added a validator class to desktop launches. Currently used for macOS

desktop/src/main/java/com/shatteredpixel/shatteredpixeldungeon/desktop/DesktopLaunchValidator.java

@@ -0,0 +1,96 @@
+/*
+ * Pixel Dungeon
+ * Copyright (C) 2012-2015 Oleg Dolya
+ *
+ * Shattered Pixel Dungeon
+ * Copyright (C) 2014-2019 Evan Debenham
+ *
+ * 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, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 <http://www.gnu.org/licenses/>
+ */
+
+package com.shatteredpixel.shatteredpixeldungeon.desktop;
+
+import com.badlogic.gdx.utils.SharedLibraryLoader;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.lang.management.ManagementFactory;
+import java.util.ArrayList;
+
+public class DesktopLaunchValidator {
+
+	//Validates that the launching JVM is correctly configured
+	// and attempts to launch a new one if it is not
+	// returns false if current JVM is invalid and should be killed.
+	public static boolean verifyValidJVMState(String[] args){
+
+		//mac computers require the -XstartOnFirstThread JVM argument
+		if (SharedLibraryLoader.isMac){
+
+			// If XstartOnFirstThread is present and enabled, we can return true
+			if ("1".equals(System.getenv("JAVA_STARTED_ON_FIRST_THREAD_" +
+					ManagementFactory.getRuntimeMXBean().getName().split("@")[0]))) {
+				return true;
+			}
+
+			// Check if we are the relaunched process, if so return true to avoid looping.
+			// The game will likely crash, but that's unavoidable at this point.
+			if ("true".equals(System.getProperty("shpdRelaunched"))){
+				System.err.println("Error: Could not verify new process is running on the first thread. Trying to run the game anyway...");
+				return true;
+			}
+
+			// Relaunch a new jvm process with the same arguments, plus -XstartOnFirstThread
+			String sep = System.getProperty("file.separator");
+
+			ArrayList<String> jvmArgs = new ArrayList<>();
+			jvmArgs.add(System.getProperty("java.home") + sep + "bin" + sep + "java");
+			jvmArgs.add("-XstartOnFirstThread");
+			jvmArgs.add("-DshpdRelaunched=true");
+			jvmArgs.addAll(ManagementFactory.getRuntimeMXBean().getInputArguments());
+			jvmArgs.add("-cp");
+			jvmArgs.add(System.getProperty("java.class.path"));
+			jvmArgs.add(DesktopLauncher.class.getName());
+
+			System.err.println("Error: ShatteredPD must start on the first thread in order to work on macOS.");
+			System.err.println("  To avoid this error, run the game with the \"-XstartOnFirstThread\" argument");
+			System.err.println("  Now attempting to relaunch the game on the first thread automatically:\n");
+
+			try {
+				Process process = new ProcessBuilder(jvmArgs).redirectErrorStream(true).start();
+				BufferedReader out = new BufferedReader(new InputStreamReader(process.getInputStream()));
+				String line;
+
+				//Relay console output from the relaunched process
+				while ((line = out.readLine()) != null) {
+					if (line.toLowerCase().startsWith("error")){
+						System.err.println(line);
+					} else {
+						System.out.println(line);
+					}
+				}
+
+				process.waitFor();
+			} catch (Exception e) {
+				e.printStackTrace();
+			}
+
+			return false;
+
+		}
+
+		return true;
+	}
+
+}

desktop/src/main/java/com/shatteredpixel/shatteredpixeldungeon/desktop/DesktopLauncher.java

@@ -41,7 +41,12 @@ import java.io.PrintWriter;
 import java.io.StringWriter;
 
 public class DesktopLauncher {
-	public static void main (String[] arg) {
+
+	public static void main (String[] args) {
+
+		if (!DesktopLaunchValidator.verifyValidJVMState(args)){
+			return;
+		}
 		
 		final String title;
 		if (DesktopLauncher.class.getPackage().getSpecificationTitle() == null){