/*

 * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 * @test

 * @summary javac should generate method parameters correctly.

 */

// key: opt.arg.parameters

import com.sun.tools.classfile.*;

import com.sun.tools.javac.file.JavacFileManager;

import com.sun.tools.javac.main.Main;

import com.sun.tools.javac.util.Context;

import com.sun.tools.javac.util.Name;

import com.sun.tools.javac.util.Names;

import java.io.*;

import javax.lang.model.element.*;

import java.util.*;

public class MethodParameters {

    static final String Foo_name = "Foo";

    static final String Foo_contents =

        "public class Foo {\n" +

        "  Foo() {}\n" +

        "  void foo0() {}\n" +

        "  void foo2(int j, int k) {}\n" +

        "}";

    static final String Bar_name = "Bar";

    static final String Bar_contents =

        "public class Bar {\n" +

        "  Bar(int i) {}" +

        "  Foo foo() { return new Foo(); }\n" +

        "}";

    static final String Baz_name = "Baz";

    static final String Baz_contents =

        "public class Baz {\n" +

        "  int baz;" +

        "  Baz(int i) {}" +

        "}";

    static final String Qux_name = "Qux";

    static final String Qux_contents =

        "public class Qux extends Baz {\n" +

        "  Qux(int i) { super(i); }" +

        "}";

    static final File classesdir = new File("methodparameters");

    public static void main(String... args) throws Exception {

        new MethodParameters().run();

    }

    void run() throws Exception {

        classesdir.mkdir();

        final File Foo_java =

            writeFile(classesdir, Foo_name + ".java", Foo_contents);

        final File Bar_java =

            writeFile(classesdir, Bar_name + ".java", Bar_contents);

        final File Baz_java =

            writeFile(classesdir, Baz_name + ".java", Baz_contents);

        System.err.println("Test compile with -parameter");

        compile("-parameters", "-d", classesdir.getPath(), Foo_java.getPath());

        // First test: make sure javac doesn't choke to death on

        // MethodParameter attributes

        System.err.println("Test compile with classfile containing MethodParameter attributes");

        compile("-parameters", "-d", classesdir.getPath(),

                "-cp", classesdir.getPath(), Bar_java.getPath());

        System.err.println("Examine class foo");

        checkFoo();

        checkBar();

        System.err.println("Test debug information conflict");

        compile("-g", "-parameters", "-d", classesdir.getPath(),

                "-cp", classesdir.getPath(), Baz_java.getPath());

        System.err.println("Introducing debug information conflict");

        Baz_java.delete();

        modifyBaz(false);

        System.err.println("Checking language model");

        inspectBaz();

        System.err.println("Permuting attributes");

        modifyBaz(true);

        System.err.println("Checking language model");

        inspectBaz();

        if(0 != errors)

            throw new Exception("MethodParameters test failed with " +

                                errors + " errors");

    }

    void inspectBaz() throws Exception {

        final File Qux_java =

            writeFile(classesdir, Qux_name + ".java", Qux_contents);

        final String[] args = { "-XDsave-parameter-names", "-d",

                                classesdir.getPath(),

                                "-cp", classesdir.getPath(),

                                Qux_java.getPath() };

        final StringWriter sw = new StringWriter();

        final PrintWriter pw = new PrintWriter(sw);

        // We need to be able to crack open javac and look at its data

        // structures.  We'll rig up a compiler instance, but keep its

        // Context, thus allowing us to get at the ClassReader.

        Context context = new Context();

        Main comp =  new Main("javac", pw);

        JavacFileManager.preRegister(context);

        // Compile Qux, which uses Baz.

        comp.compile(args, context);

        pw.close();

        final String out = sw.toString();

        if (out.length() > 0)

            System.err.println(out);

        // Now get the class reader, construct a name for Baz, and load it.

        com.sun.tools.javac.jvm.ClassReader cr =

            com.sun.tools.javac.jvm.ClassReader.instance(context);

        Name name = Names.instance(context).fromString(Baz_name);

        // Now walk down the language model and check the name of the

        // parameter.

        final Element baz = cr.loadClass(name);

        for (Element e : baz.getEnclosedElements()) {

            if (e instanceof ExecutableElement) {

                final ExecutableElement ee = (ExecutableElement) e;

                final List<? extends VariableElement> params =

                    ee.getParameters();

                if (1 != params.size())

                    throw new Exception("Classfile Baz badly formed: wrong number of methods");

                final VariableElement param = params.get(0);

                if (!param.getSimpleName().contentEquals("baz")) {

                    errors++;

                    System.err.println("javac did not correctly resolve the metadata conflict, parameter's name reads as " + param.getSimpleName());

                } else

                    System.err.println("javac did correctly resolve the metadata conflict");

            }

        }

    }

    void modifyBaz(boolean flip) throws Exception {

        final File Baz_class = new File(classesdir, Baz_name + ".class");

        final ClassFile baz = ClassFile.read(Baz_class);

        final int ind = baz.constant_pool.getUTF8Index("baz");

        MethodParameters_attribute mpattr = null;

        int mpind = 0;

        Code_attribute cattr = null;

        int cind = 0;

        // Find the indexes of the MethodParameters and the Code attributes

        if (baz.methods.length != 1)

            throw new Exception("Classfile Baz badly formed: wrong number of methods");

        if (!baz.methods[0].getName(baz.constant_pool).equals("<init>"))

            throw new Exception("Classfile Baz badly formed: method has name " +

                                baz.methods[0].getName(baz.constant_pool));

        for (int i = 0; i < baz.methods[0].attributes.attrs.length; i++) {

            if (baz.methods[0].attributes.attrs[i] instanceof

                MethodParameters_attribute) {

                mpattr = (MethodParameters_attribute)

                    baz.methods[0].attributes.attrs[i];

                mpind = i;

            } else if (baz.methods[0].attributes.attrs[i] instanceof

                       Code_attribute) {

                cattr = (Code_attribute) baz.methods[0].attributes.attrs[i];

                cind = i;

            }

        }

        if (null == mpattr)

            throw new Exception("Classfile Baz badly formed: no method parameters info");

        if (null == cattr)

            throw new Exception("Classfile Baz badly formed: no local variable table");

        int flags = mpattr.method_parameter_table[0].flags;

        // Alter the MethodParameters attribute, changing the name of

        // the parameter from i to baz.  This requires Black Magic...

        //

        // The (well-designed) classfile library (correctly) does not

        // allow us to mess around with the attribute data structures,

        // or arbitrarily generate new ones.

        //

        // Instead, we install a new subclass of Attribute that

        // hijacks the Visitor pattern and outputs the sequence of

        // bytes that we want.  This only works in this particular

        // instance, because we know we'll only every see one kind of

        // visitor.

        //

        // If anyone ever changes the makeup of the Baz class, or

        // tries to install some kind of visitor that gets run prior

        // to serialization, this will break.

        baz.methods[0].attributes.attrs[mpind] =

            new Attribute(mpattr.attribute_name_index,

                          mpattr.attribute_length) {

                public <R, D> R accept(Visitor<R, D> visitor, D data) {

                    if (data instanceof ByteArrayOutputStream) {

                        ByteArrayOutputStream out =

                            (ByteArrayOutputStream) data;

                        out.write(1);

                        out.write((ind >> 8) & 0xff);

                        out.write(ind & 0xff);

                        out.write((flags >> 24) & 0xff);

                        out.write((flags >> 16) & 0xff);

                        out.write((flags >> 8) & 0xff);

                        out.write(flags & 0xff);

                    } else

                        throw new RuntimeException("Output stream is of type " + data.getClass() + ", which is not handled by this test.  Update the test and it should work.");

                    return null;

                }

            };

        // Flip the code and method attributes.  This is for checking

        // that order doesn't matter.

        if (flip) {

            baz.methods[0].attributes.attrs[mpind] = cattr;

            baz.methods[0].attributes.attrs[cind] = mpattr;

        }

        new ClassWriter().write(baz, Baz_class);

    }

    // Run a bunch of structural tests on foo to make sure it looks right.

    void checkFoo() throws Exception {

        final File Foo_class = new File(classesdir, Foo_name + ".class");

        final ClassFile foo = ClassFile.read(Foo_class);

        for (int i = 0; i < foo.methods.length; i++) {

            System.err.println("Examine method Foo." + foo.methods[i].getName(foo.constant_pool));

            if (foo.methods[i].getName(foo.constant_pool).equals("foo2")) {

                for (int j = 0; j < foo.methods[i].attributes.attrs.length; j++)

                    if (foo.methods[i].attributes.attrs[j] instanceof

                        MethodParameters_attribute) {

                        MethodParameters_attribute mp =

                            (MethodParameters_attribute)

                            foo.methods[i].attributes.attrs[j];

                        System.err.println("Foo.foo2 should have 2 parameters: j and k");

                        if (2 != mp.method_parameter_table_length)

                            error("expected 2 method parameter entries in foo2, got " +

                                  mp.method_parameter_table_length);

                        else if (!foo.constant_pool.getUTF8Value(mp.method_parameter_table[0].name_index).equals("j"))

                            error("expected first parameter to foo2 to be \"j\", got \"" +

                                  foo.constant_pool.getUTF8Value(mp.method_parameter_table[0].name_index) +

                                  "\" instead");

                        else if  (!foo.constant_pool.getUTF8Value(mp.method_parameter_table[1].name_index).equals("k"))

                            error("expected first parameter to foo2 to be \"k\", got \"" +

                                  foo.constant_pool.getUTF8Value(mp.method_parameter_table[1].name_index) +

                                  "\" instead");

                    }

            }

            else if (foo.methods[i].getName(foo.constant_pool).equals("<init>")) {

                for (int j = 0; j < foo.methods[i].attributes.attrs.length; j++) {

                    if (foo.methods[i].attributes.attrs[j] instanceof

                        MethodParameters_attribute)

                        error("Zero-argument constructor shouldn't have MethodParameters");

                }

            }

            else if (foo.methods[i].getName(foo.constant_pool).equals("foo0")) {

                for (int j = 0; j < foo.methods[i].attributes.attrs.length; j++)

                    if (foo.methods[i].attributes.attrs[j] instanceof

                        MethodParameters_attribute)

                        error("Zero-argument method shouldn't have MethodParameters");

            }

            else

                error("Unknown method " + foo.methods[i].getName(foo.constant_pool) + " showed up in class Foo");

        }

    }

    // Run a bunch of structural tests on Bar to make sure it looks right.

    void checkBar() throws Exception {

        final File Bar_class = new File(classesdir, Bar_name + ".class");

        final ClassFile bar = ClassFile.read(Bar_class);

        for (int i = 0; i < bar.methods.length; i++) {

            System.err.println("Examine method Bar." + bar.methods[i].getName(bar.constant_pool));

            if (bar.methods[i].getName(bar.constant_pool).equals("<init>")) {

                for (int j = 0; j < bar.methods[i].attributes.attrs.length; j++)

                    if (bar.methods[i].attributes.attrs[j] instanceof

                        MethodParameters_attribute) {

                        MethodParameters_attribute mp =

                            (MethodParameters_attribute)

                            bar.methods[i].attributes.attrs[j];

                        System.err.println("Bar constructor should have 1 parameter: i");

                        if (1 != mp.method_parameter_table_length)

                            error("expected 1 method parameter entries in constructor, got " +

                                  mp.method_parameter_table_length);

                        else if (!bar.constant_pool.getUTF8Value(mp.method_parameter_table[0].name_index).equals("i"))

                            error("expected first parameter to foo2 to be \"i\", got \"" +

                                  bar.constant_pool.getUTF8Value(mp.method_parameter_table[0].name_index) +

                                  "\" instead");

                    }

            }

            else if (bar.methods[i].getName(bar.constant_pool).equals("foo")) {

                for (int j = 0; j < bar.methods[i].attributes.attrs.length; j++) {

                    if (bar.methods[i].attributes.attrs[j] instanceof

                        MethodParameters_attribute)

                        error("Zero-argument constructor shouldn't have MethodParameters");

                }

            }

        }

    }

    String compile(String... args) throws Exception {

        System.err.println("compile: " + Arrays.asList(args));

        StringWriter sw = new StringWriter();

        PrintWriter pw = new PrintWriter(sw);

        int rc = com.sun.tools.javac.Main.compile(args, pw);

        pw.close();

        String out = sw.toString();

        if (out.length() > 0)

            System.err.println(out);

        if (rc != 0)

            error("compilation failed, rc=" + rc);

        return out;

    }

    File writeFile(File dir, String path, String body) throws IOException {

        File f = new File(dir, path);

        f.getParentFile().mkdirs();

        FileWriter out = new FileWriter(f);

        out.write(body);

        out.close();

        return f;

    }

    void error(String msg) {

        System.err.println("Error: " + msg);

        errors++;

    }

    int errors;

}