com.google.java.contract.core.agent.HelperClassAdapter.java Source code

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Here is the source code for com.google.java.contract.core.agent.HelperClassAdapter.java

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/*
 * Copyright 2010 Google Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */
package com.google.java.contract.core.agent;

import com.google.java.contract.Requires;
import com.google.java.contract.core.util.JavaUtils;
import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;

import javax.tools.JavaFileObject.Kind;

/**
 * Adds debug information to a helper class.
 *
 * @author nhat.minh.le@huoc.org (Nhat Minh L)
 */
class HelperClassAdapter extends ClassVisitor {
    protected class HelperMethodAdapter extends LineNumberingMethodAdapter {
        /**
         * Constructs a new HelperMethodAdapter.
         *
         * @param mv the MethodVisitor this adapter delegates to
         * @param access the access flags of the method
         * @param name the name of the method
         * @param desc the descriptor of the method
         */
        @Requires({ "mv != null", "name != null", "desc != null" })
        public HelperMethodAdapter(MethodVisitor mv, int access, String name, String desc) {
            super(mv, access, name, desc);
        }

        @Override
        public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
            if (Type.getType(desc).getInternalName()
                    .equals("com/google/java/contract/core/agent/ContractMethodSignature")) {
                return new AnnotationVisitor(Opcodes.ASM5) {
                    @Override
                    public void visit(String name, Object value) {
                        if (name.equals("lines")) {
                            lineNumbers = ContractMethodSignatures.getLineNumbers(value);
                        }
                    }
                };
            }
            return super.visitAnnotation(desc, visible);
        }
    }

    @Requires("cv != null")
    public HelperClassAdapter(ClassVisitor cv) {
        super(Opcodes.ASM5, cv);
    }

    @Override
    public void visitSource(String source, String debug) {
        /*
         * Work around bogus file names and remove helper suffix if
         * found. The compiler, as invoked in ContractJavaCompiler,
         * produces SourceFile entries with a trailing ']' for no apparent
         * reason; this method removes any trailing characters after the
         * source extension.
         */
        String name = source.substring(0, source.lastIndexOf(Kind.SOURCE.extension));
        if (name.endsWith(JavaUtils.HELPER_CLASS_SUFFIX)) {
            int lengthSansSuffix = name.length() - JavaUtils.HELPER_CLASS_SUFFIX.length();
            name = name.substring(0, lengthSansSuffix);
        }
        name += Kind.SOURCE.extension;
        cv.visitSource(name, debug);
    }

    @Override
    public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
        MethodVisitor mv = cv.visitMethod(access, name, desc, signature, exceptions);
        return new HelperMethodAdapter(mv, access, name, desc);
    }
}