Examples with BootstrapMethodsAttribute javassist.bytecode.BootstrapMethodsAttribute used on opensource projects

Example 1 with BootstrapMethodsAttribute

use of javassist.bytecode.BootstrapMethodsAttribute in project fakereplace by fakereplace.

the class FakeMethodCallManipulator method handleLambdas.

private void handleLambdas(ClassFile file, Map<Integer, Data> knownFakeMethodCallLocations, ConstPool pool) {
    // check the bootstrapmethod's attribute
    // this makes lambda support work
    AttributeInfo bootstrapMethods = file.getAttribute(BootstrapMethodsAttribute.tag);
    if (bootstrapMethods instanceof BootstrapMethodsAttribute) {
        BootstrapMethodsAttribute boot = (BootstrapMethodsAttribute) bootstrapMethods;
        boolean replaceBootstrap = false;
        BootstrapMethodsAttribute.BootstrapMethod[] replacement = boot.getMethods();
        for (BootstrapMethodsAttribute.BootstrapMethod method : replacement) {
            // initial support for lambda replacement
            // first we look for all invocations on LambdaMetafactory
            int kind = pool.getMethodHandleKind(method.methodRef);
            if (kind == ConstPool.REF_invokeStatic) {
                int nameAndType = pool.getMethodHandleIndex(method.methodRef);
                String className = pool.getMethodrefClassName(nameAndType);
                String methodName = pool.getMethodrefName(nameAndType);
                if (className.equals(LambdaMetafactory.class.getName())) {
                    if (methodName.equals("metafactory")) {
                        // we have a lambda instance
                        // does it reference a new method
                        int methodHandleArg = method.arguments[1];
                        kind = pool.getMethodHandleKind(methodHandleArg);
                        if (kind == ConstPool.REF_invokeStatic || kind == ConstPool.REF_invokeVirtual || kind == ConstPool.REF_invokeSpecial) {
                            int methodRefArg = pool.getMethodHandleIndex(methodHandleArg);
                            if (knownFakeMethodCallLocations.containsKey(methodRefArg)) {
                                // the lambda references a new method
                                replaceBootstrap = true;
                                Data target = knownFakeMethodCallLocations.get(methodRefArg);
                                String type = pool.getMethodrefType(methodRefArg);
                                String name = pool.getMethodrefName(methodRefArg);
                                if (kind != ConstPool.REF_invokeStatic) {
                                    type = "(" + DescriptorUtils.extToInt(file.getName()) + type.substring(1);
                                }
                                int newMethodRef = pool.addMethodrefInfo(pool.addClassInfo(target.getProxyName()), name, type);
                                int newMethodHandle = pool.addMethodHandleInfo(ConstPool.REF_invokeStatic, newMethodRef);
                                method.arguments[1] = newMethodHandle;
                            }
                        }
                    }
                }
            }
        }
        if (replaceBootstrap) {
            file.addAttribute(new BootstrapMethodsAttribute(file.getConstPool(), replacement));
        }
    }
}