fixed bugs, memory leaks, etc

src/main/java/dev/zprestige/prestige/inject/Bootstrap.java

@@ -8,6 +8,7 @@ import dev.zprestige.prestige.ui.mc.Entry;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Function;
 import java.util.function.ToIntBiFunction;
 import net.fabricmc.loader.api.FabricLoader;
@@ -22,6 +23,8 @@ import net.minecraft.client.MinecraftClient;
  */
 public final class Bootstrap {
     private static boolean started;
+    /** Class bytes as they were before the hooks, kept so self destruct can put the game classes back. */
+    private static final Map<Class<?>, byte[]> ORIGINALS = new ConcurrentHashMap<>();
 
     private Bootstrap() {}
 
@@ -85,6 +88,7 @@ public final class Bootstrap {
                 for (byte[] helper : result.helpers().values()) Definer.define(helper);
                 int code = redefine.applyAsInt(type, result.target());
                 if (code != 0) throw new IllegalStateException("redefine returned JVMTI error " + code);
+                ORIGINALS.put(type, current);
                 report.redefined++;
                 report.moved += result.movedMethods();
             } catch (Throwable t) {
@@ -96,6 +100,31 @@ public final class Bootstrap {
         return report;
     }
 
+    /** True when this client was injected, i.e. hooks were applied through JVMTI and can be taken out again. */
+    public static boolean isInjected() {
+        return !ORIGINALS.isEmpty();
+    }
+
+    /**
+     * Self destruct, part 1: redefines every hooked class back to its original bytes so no game code references the client any
+     * more. Returns the number of classes that could not be restored.
+     */
+    public static int uninstall() {
+        int failed = 0;
+        for (Map.Entry<Class<?>, byte[]> entry : ORIGINALS.entrySet()) {
+            try {
+                int code = NativeBridge.redefine(entry.getKey(), entry.getValue());
+                if (code != 0) throw new IllegalStateException("JVMTI error " + code);
+                ORIGINALS.remove(entry.getKey());
+            } catch (Throwable t) {
+                failed++;
+                log("could not restore " + entry.getKey().getName() + ": " + t);
+            }
+        }
+        log("hooks removed" + (failed == 0 ? "" : ", " + failed + " classes could not be restored"));
+        return failed;
+    }
+
     private static void initClient() {
         try {
             new Prestige().onInitialize();

src/main/java/dev/zprestige/prestige/inject/NativeBridge.java

@@ -10,6 +10,9 @@ public final class NativeBridge {
     /** Appends a line to prestige-native.log, which the injector tails to show progress. */
     public static native void log(String message);
 
+    /** Disables the class file load hook and unloads prestige_native.dll shortly afterwards; nothing may call the natives after this. */
+    public static native void release();
+
     /** JVMTI RedefineClasses for one class; returns the JVMTI error code, 0 on success. */
     public static native int redefine(Class<?> type, byte[] bytes);
 }