/***
 * ASM tests
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.objectweb.asm;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.lang.instrument.Instrumentation;
import java.security.ProtectionDomain;

import junit.framework.TestSuite;

import org.objectweb.asm.util.TraceClassVisitor;

/**
 * ClassWriter tests.
 *
 * @author Eric Bruneton
 */
public class ClassWriterComputeFramesTest extends AbstractTest {

    public static void premain(
        final String agentArgs,
        final Instrumentation inst)
    {
        inst.addTransformer(new ClassFileTransformer() {
            public byte[] transform(
                final ClassLoader loader,
                final String className,
                final Class<?> classBeingRedefined,
                final ProtectionDomain domain,
                final byte[] classFileBuffer)
                    throws IllegalClassFormatException
            {
                String n = className.replace('/', '.');
                if (n.indexOf("junit") != -1) {
                    return null;
                }
                if (agentArgs.length() == 0 || n.indexOf(agentArgs) != -1) {
                    return transformClass(n, classFileBuffer);
                } else {
                    return null;
                }
            }
        });
    }

    static byte[] transformClass(final String n, final byte[] clazz) {
        ClassReader cr = new ClassReader(clazz);
        ClassWriter cw = new ComputeClassWriter(ClassWriter.COMPUTE_FRAMES);
        cr.accept(new ClassVisitor(Opcodes.ASM4, cw) {

            @Override
            public void visit(
                final int version,
                final int access,
                final String name,
                final String signature,
                final String superName,
                final String[] interfaces)
            {
                super.visit((version & 0xFFFF) < Opcodes.V1_6 ? Opcodes.V1_6 : version,
                        access,
                        name,
                        signature,
                        superName,
                        interfaces);
            }

        }, ClassReader.SKIP_FRAMES);
        return cw.toByteArray();
    }

    public static TestSuite suite() throws Exception {
        return new ClassWriterComputeFramesTest().getSuite();
    }

    @Override
    public void test() throws Exception {
        try {
            Class.forName(n, true, getClass().getClassLoader());
        } catch (NoClassDefFoundError ncdfe) {
            // ignored
        } catch (UnsatisfiedLinkError ule) {
            // ignored
        } catch (ClassFormatError cfe) {
            fail(cfe.getMessage());
        } catch (VerifyError ve) {
            String s = n.replace('.', '/') + ".class";
            InputStream is = getClass().getClassLoader().getResourceAsStream(s);
            ClassReader cr = new ClassReader(is);
            byte[] b = transformClass("", cr.b);
            StringWriter sw1 = new StringWriter();
            StringWriter sw2 = new StringWriter();
            sw2.write(ve.toString() + "\n");
            ClassVisitor cv1 = new TraceClassVisitor(new PrintWriter(sw1));
            ClassVisitor cv2 = new TraceClassVisitor(new PrintWriter(sw2));
            cr.accept(cv1, 0);
            new ClassReader(b).accept(cv2, 0);
            String s1 = sw1.toString();
            String s2 = sw2.toString();
            assertEquals("different data", s1, s2);
        }
    }
}

/**
 * A ClassWriter that computes the common super class of two classes without
 * actually loading them with a ClassLoader.
 *
 * @author Eric Bruneton
 */
class ComputeClassWriter extends ClassWriter {

    private ClassLoader l = getClass().getClassLoader();

    public ComputeClassWriter(final int flags) {
        super(flags);
    }

    @Override
    protected String getCommonSuperClass(final String type1, final String type2)
    {
        try {
            ClassReader info1 = typeInfo(type1);
            ClassReader info2 = typeInfo(type2);
            if ((info1.getAccess() & Opcodes.ACC_INTERFACE) != 0) {
                if (typeImplements(type2, info2, type1)) {
                    return type1;
                } else {
                    return "java/lang/Object";
                }
            }
            if ((info2.getAccess() & Opcodes.ACC_INTERFACE) != 0) {
                if (typeImplements(type1, info1, type2)) {
                    return type2;
                } else {
                    return "java/lang/Object";
                }
            }
            StringBuilder b1 = typeAncestors(type1, info1);
            StringBuilder b2 = typeAncestors(type2, info2);
            String result = "java/lang/Object";
            int end1 = b1.length();
            int end2 = b2.length();
            while (true) {
                int start1 = b1.lastIndexOf(";", end1 - 1);
                int start2 = b2.lastIndexOf(";", end2 - 1);
                if (start1 != -1 && start2 != -1
                        && end1 - start1 == end2 - start2)
                {
                    String p1 = b1.substring(start1 + 1, end1);
                    String p2 = b2.substring(start2 + 1, end2);
                    if (p1.equals(p2)) {
                        result = p1;
                        end1 = start1;
                        end2 = start2;
                    } else {
                        return result;
                    }
                } else {
                    return result;
                }
            }
        } catch (IOException e) {
            throw new RuntimeException(e.toString());
        }
    }

    /**
     * Returns the internal names of the ancestor classes of the given type.
     *
     * @param type the internal name of a class or interface.
     * @param info the ClassReader corresponding to 'type'.
     * @return a StringBuilder containing the ancestor classes of 'type',
     *         separated by ';'. The returned string has the following format:
     *         ";type1;type2 ... ;typeN", where type1 is 'type', and typeN is a
     *         direct subclass of Object. If 'type' is Object, the returned
     *         string is empty.
     * @throws IOException if the bytecode of 'type' or of some of its ancestor
     *         class cannot be loaded.
     */
    private StringBuilder typeAncestors(String type, ClassReader info)
            throws IOException
    {
        StringBuilder b = new StringBuilder();
        while (!"java/lang/Object".equals(type)) {
            b.append(';').append(type);
            type = info.getSuperName();
            info = typeInfo(type);
        }
        return b;
    }

    /**
     * Returns true if the given type implements the given interface.
     *
     * @param type the internal name of a class or interface.
     * @param info the ClassReader corresponding to 'type'.
     * @param itf the internal name of a interface.
     * @return true if 'type' implements directly or indirectly 'itf'
     * @throws IOException if the bytecode of 'type' or of some of its ancestor
     *         class cannot be loaded.
     */
    private boolean typeImplements(String type, ClassReader info, String itf)
            throws IOException
    {
        while (!"java/lang/Object".equals(type)) {
            String[] itfs = info.getInterfaces();
            for (int i = 0; i < itfs.length; ++i) {
                if (itfs[i].equals(itf)) {
                    return true;
                }
            }
            for (int i = 0; i < itfs.length; ++i) {
                if (typeImplements(itfs[i], typeInfo(itfs[i]), itf)) {
                    return true;
                }
            }
            type = info.getSuperName();
            info = typeInfo(type);
        }
        return false;
    }

    /**
     * Returns a ClassReader corresponding to the given class or interface.
     *
     * @param type the internal name of a class or interface.
     * @return the ClassReader corresponding to 'type'.
     * @throws IOException if the bytecode of 'type' cannot be loaded.
     */
    private ClassReader typeInfo(final String type) throws IOException {
        InputStream is = l.getResourceAsStream(type + ".class");
        try {
            return new ClassReader(is);
        } finally {
            is.close();
        }
    }
}
