com.google.auto.value.processor.AbstractMethodLister Maven / Gradle / Ivy
/*
* Copyright (C) 2013 Google, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.auto.value.processor;
import com.google.common.collect.ImmutableList;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Modifier;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
/**
* A class file parser that lists the no-arg abstract methods in a class.
*
* @author Éamonn McManus
*/
class AbstractMethodLister {
private final InputStream inputStream;
AbstractMethodLister(InputStream inputStream) {
this.inputStream = inputStream;
}
ImmutableList abstractNoArgMethods() {
try {
return abstractNoArgMethodsX();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
private ImmutableList abstractNoArgMethodsX() throws IOException {
ClassReader classReader = new ClassReader(inputStream);
RecordingClassVisitor classVisitor = new RecordingClassVisitor();
classReader.accept(classVisitor, 0);
return classVisitor.abstractNoArgMethods.build();
}
private static class RecordingClassVisitor extends ClassVisitor {
private final ImmutableList.Builder abstractNoArgMethods = ImmutableList.builder();
RecordingClassVisitor() {
super(Opcodes.ASM5);
}
@Override
public MethodVisitor visitMethod(
int access, String name, String desc, String signature, String[] exceptions) {
// The class-file method descriptor desc is a string that will contain "()" only if the
// method has no arguments, and will end with "V" (actually "()V") only if the method
// is void.
if (Modifier.isAbstract(access) && desc.contains("()") && !desc.endsWith("V")) {
abstractNoArgMethods.add(name);
}
return super.visitMethod(access, name, desc, signature, exceptions);
}
}
}