gradle/utils.gradle

import org.codehaus.groovy.classgen.AnnotationVisitor
import org.objectweb.asm.ClassWriter
import org.objectweb.asm.FieldVisitor
import org.objectweb.asm.Label
import org.objectweb.asm.MethodVisitor

import static org.objectweb.asm.Opcodes.*

/*
* Copyright 2003-2012 the original author or authors.
*
* 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.
*/

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath "org.ow2.asm:asm:4.0"
    }
}

/**
 * This tasks generates an utility class which allows sneaky throwing.
 */
task exceptionUtils {
    ext.classFiles = [
            "${compileCompilerJava.destinationDir}/org/codehaus/groovy/runtime/ExceptionUtils.class",
            "${compileJava.destinationDir}/org/codehaus/groovy/runtime/ExceptionUtils.class"]
    outputs.files classFiles

    doLast {
        ClassWriter cw = new ClassWriter(0);
        FieldVisitor fv;
        MethodVisitor mv;
        AnnotationVisitor av0;

        cw.visit(V1_5, ACC_PUBLIC + ACC_SUPER, "org/codehaus/groovy/runtime/ExceptionUtils", null, "java/lang/Object", null);

        cw.visitSource("ExceptionUtils.java", null);

        mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
        mv.visitCode();
        Label l0 = new Label();
        mv.visitLabel(l0);
        mv.visitLineNumber(18, l0);
        mv.visitVarInsn(ALOAD, 0);
        mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V");
        mv.visitInsn(RETURN);
        Label l1 = new Label();
        mv.visitLabel(l1);
        mv.visitLocalVariable("this", "Lorg/codehaus/groovy/runtime/ExceptionUtils;", null, l0, l1, 0);
        mv.visitMaxs(1, 1);
        mv.visitEnd();

        mv = cw.visitMethod(ACC_PUBLIC + ACC_STATIC, "sneakyThrow", "(Ljava/lang/Throwable;)V", null, null);
        mv.visitCode();
        Label l2 = new Label();
        mv.visitLabel(l2);
        mv.visitLineNumber(20, l2);
        mv.visitVarInsn(ALOAD, 0);
        mv.visitInsn(ATHROW);
        Label l3 = new Label();
        mv.visitLabel(l3);
        mv.visitLocalVariable("e", "Ljava/lang/Throwable;", null, l2, l3, 0);
        mv.visitMaxs(1, 1);
        mv.visitEnd();

        cw.visitEnd();

        logger.lifecycle("Generating ExceptionUtils")
        classFiles.each { classFile ->
            def output = file(classFile)
            output.parentFile.mkdirs()
            output.withOutputStream {
                it << cw.toByteArray()
            }
        }
    }
}