mitigation: Mitigate Veil 3.1.0 using macOS imgui natives

See
FoundryMC/Veil@8e0e093
for when they fixed it. This commit simply edits `setImGuiPath()` to
nothing so we are able to properly override `imgui.library.name` for
older, broken Veil versions.

Author: alexytomi

methods_injector_agent/src/main/java/org/angelauramc/methodsInjectorAgent/mod_compatibility_injector/VeilImguiOverrideDisable.java

@@ -0,0 +1,75 @@
+package org.angelauramc.methodsInjectorAgent.mod_compatibility_injector;
+
+import java.lang.instrument.ClassFileTransformer;
+import java.lang.instrument.Instrumentation;
+import java.security.ProtectionDomain;
+
+import org.angelauramc.methodsInjectorAgent.lwjgl2_methods_injector.ALC10Injector;
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.ClassVisitor;
+import org.objectweb.asm.ClassWriter;
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
+
+// Older veil versions overrides imgui.library.name with libimgui-javaarm64.dylib if on arm/arm64
+// which isn't the right lib. So veil fails to load.
+public class VeilImguiOverrideDisable extends ClassVisitor implements ClassFileTransformer  {
+    protected VeilImguiOverrideDisable(int api) {
+        super(api);
+    }
+
+    public static void premain(String args, Instrumentation inst) {
+        inst.addTransformer(new ClassFileTransformer() {
+            public byte[] transform(ClassLoader l, String name, Class c,
+                                    ProtectionDomain d, byte[] b) {
+                if (!"foundry/veil/impl/client/imgui/VeilImGuiImpl".equals(name)) {
+                    return null;
+                }
+                ClassReader cr = new ClassReader(b);
+                ClassWriter cw = new ClassWriter(cr, 0);
+                ClassVisitor cv = new DisableMethodAdapter(cw);
+                cr.accept(cv, 0);
+                return cw.toByteArray();
+            }
+        });
+    }
+
+    public static class DisableMethodAdapter extends ClassVisitor {
+
+        public DisableMethodAdapter(ClassVisitor cv) {
+            super(Opcodes.ASM4, cv);
+        }
+
+        @Override
+        public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
+            MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);
+            if (name.equals("setImGuiPath")
+                    && desc.equals("()V")) {
+                try { // Minecraft makes it ugly if we use println
+                    System.out.write(("Amethyst-Android: Patching VeilImGuiImpl for faulty setImGuiPath()...\n" +
+                            "This issue is fixed in Veil 3.1.1 and above. See https://github.com/FoundryMC/Veil/commit/8e0e09365049a106bfa3634e2ed78a0310c5b4df\n" +
+                            "The intended target of this patch is Veil 3.1.0 and below. If you see this log output without Veil 3.1.0 or lower running, please send a bug report to Amethyst-Android.\n" +
+                            "https://github.com/AngelAuraMC/Amethyst-Android/issues/new?template=bug_report.yml").getBytes());
+
+                    System.out.flush();
+                } catch (Exception ignored) {}
+                return getMethodVisitor(mv);
+            }
+            return mv;
+        }
+        private MethodVisitor getMethodVisitor(MethodVisitor delegate) {
+            return new MethodVisitor(this.api, null) {
+                @Override
+                public void visitCode() {
+                    delegate.visitCode();
+                    delegate.visitInsn(Opcodes.RETURN); // Add our return
+                    delegate.visitMaxs(0, 0);           // ClassWriter.COMPUTE_FRAMES will fix this
+                    delegate.visitEnd();
+                }
+            };
+        }
+    }
+}
+
+
+

methods_injector_agent/src/main/java/org/angelauramc/methodsInjectorAgent/startInjectors.java

@@ -2,6 +2,7 @@
 
 import org.angelauramc.methodsInjectorAgent.lwjgl2_methods_injector.ALC10Injector;
 import org.angelauramc.methodsInjectorAgent.lwjgl2_methods_injector.ASM5OverrideInjector;
+import org.angelauramc.methodsInjectorAgent.mod_compatibility_injector.VeilImguiOverrideDisable;
 
 import java.lang.instrument.Instrumentation;
 
@@ -19,6 +20,7 @@ public static void premain(String args, Instrumentation inst) {
             if (implVersion == null) implVersion = "not found";
             System.out.println("Amethyst-Android: Detected ASM version: " + implVersion);
             ALC10Injector.premain(args, inst);
+            VeilImguiOverrideDisable.premain(args, inst);
             // This is the version we override old asm vers with. So we add the patches
             // so the older version bugs are ported.
             if (implVersion.equals("5.0.4")) ASM5OverrideInjector.premain(args, inst);