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/*

 * @test

 * @bug 8046171

 * @summary Class redefinition must preclude changes to nest attributes

 * @comment This is a copy of test/jdk/java/lang/instrument/RedefineNestmateAttr/

 * @comment modified for JDI

 * @library /test/lib ..

 * @modules java.compiler

 * @run build TestScaffold VMConnection TargetListener TargetAdapter

 * @compile NamedBuffer.java

 * @compile Host/Host.java

 * @run main/othervm TestNestmateAttr Host

 * @compile HostA/Host.java

 * @run main/othervm TestNestmateAttr HostA

 * @compile HostAB/Host.java

 * @run main/othervm TestNestmateAttr HostAB

 * @compile HostABC/Host.java

 * @run main/othervm TestNestmateAttr HostABC

 */

/* Test Description

The basic test class is called Host and we have variants that have zero or more

nested classes named A, B, C etc. Each variant of Host is defined in source

code in its own directory i.e.

Host/Host.java defines zero nested classes

HostA/Host.java defines one nested class A

HostAB/Host.java defines two nested classes A and B (in that order)

etc.

Each Host class has the form:

  public class Host {

    public static String getID() { return "<directory name>/Host.java"; }

    < zero or more empty nested classes>

    public int m() {

        return 1; // original class

    }

  }

Under each directory is a directory "redef" with a modified version of the Host

class that changes the ID to e.g. Host/redef/Host.java, and the method m()

returns 2. This allows us to check we have the redefined class loaded.

Using Host' to represent the redefined version we test redefinition

combinations as follows:

Host:

  Host -> Host'  - succeeds m() returns 2

  Host -> HostA' - fails - added a nest member

HostA:

  HostA -> HostA'  - succeeds m() returns 2

  HostA -> Host'   - fails - removed a nest member

  HostA -> HostAB' - fails - added a nest member

  HostA -> HostB'  - fails - replaced a nest member

HostAB:

  HostAB -> HostAB'  - succeeds m() returns 2

  HostAB -> HostBA'  - succeeds m() returns 2

  HostAB -> HostA'   - fails - removed a nest member

  HostAB -> HostABC' - fails - added a nest member

  HostAB -> HostAC'  - fails - replaced a nest member

HostABC:

  HostABC -> HostABC'  - succeeds m() returns 2

  HostABC -> HostACB'  - succeeds m() returns 2

  HostABC -> HostBAC'  - succeeds m() returns 2

  HostABC -> HostBCA'  - succeeds m() returns 2

  HostABC -> HostCAB'  - succeeds m() returns 2

  HostABC -> HostCBA'  - succeeds m() returns 2

  HostABC -> HostAB'   - fails - removed a nest member

  HostABC -> HostABCD' - fails - added a nest member

  HostABC -> HostABD'  - fails - replaced a nest member

More than three nested classes doesn't add to the code coverage so

we stop here.

Note that we always try to load the redefined version even when we expect it

to fail.

We can only directly load one class Host per classloader, so to run all the

groups we either need to use new classloaders, or we reinvoke the test

requesting a different primary directory. We chose the latter using

multiple @run tags. So we proceed as follows:

 @compile Host/Host.java

 @run TestNestmateAttr Host

 @compile HostA/Host.java  - replaces previous Host.class

 @run TestNestmateAttr HostA

 @compile HostAB/Host.java  - replaces previous Host.class

 @run TestNestmateAttr HostAB

etc.

Within the test we directly compile redefined versions of the classes,

using CompilerUtil, and then read the .class file directly as a byte[].

Finally we test redefinition of the NestHost attribute - which is

conceptually simple, but in fact very tricky to do. We do that

when testing HostA so we can reuse the Host$A class.

*/

import com.sun.jdi.*;

import com.sun.jdi.event.*;

import com.sun.jdi.request.*;

import java.io.File;

import java.io.FileInputStream;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import jdk.test.lib.ByteCodeLoader;

import jdk.test.lib.compiler.CompilerUtils;

import jdk.test.lib.compiler.InMemoryJavaCompiler;

import static jdk.test.lib.Asserts.assertTrue;

/* For JDI the test is split across two VMs and so split into

   two main classes. This is the class we will run under the debugger.

   Package access so we can define in the same source file for ease of

   reference.

*/

class Target {

    // We have to load all of the variants of the classes that we will

    // attempt to redefine. This requires some in-memory compilation

    // and use of additional classloaders.

    public static void main(String[] args) throws Throwable {

        String origin = args[0];

        System.out.println("Target: Testing original Host class from " + origin);

        // Make sure the Host class loaded directly is an original version

        // and from the expected location

        Host h = new Host();

        assertTrue(h.m() == 1);

        assertTrue(Host.getID().startsWith(origin + "/"));

        // The rest of this setup is only needed for the case

        // when we perform the checkNestHostChanges() test.

        if (origin.equals("HostA")) {

            String name = "Host$A";

            // Have to do this reflectively as there is no Host$A

            // when compiling the "Host/" case.

            Class<?> nestedA = Class.forName(name); // triggers initialization

            // This is compiled as a top-level class: the $ in the name is not

            // significant to the compiler.

            String hostA = "public class " + name + " {}";

            byte[] bytes = InMemoryJavaCompiler.compile(name, hostA);

            // And we have to load this into a new classloader

            // The loaded class has not been linked (as per ClassLoader.resolveClass)

            // and so will be filtered out by VirtualMachine.allClasses(). There are

            // a number of ways to force linking - this is the simplest.

            Object o = topLevelHostA.newInstance();

            // sanity check

            assertTrue(nestedA.getClassLoader() != topLevelHostA.getClassLoader());

        }

        breakpoint();    // debugger runs to here before enabling events

        allowRedefine(); // debugger stops us here to attempt redefinitions

        System.out.println("Target executed okay");

    }

    static void allowRedefine() { }

    static void breakpoint() { }

}

public class TestNestmateAttr extends TestScaffold {

    static final String SRC = System.getProperty("test.src");

    static final String DEST = System.getProperty("test.classes");

    static final boolean VERBOSE = Boolean.getBoolean("verbose");

    static String origin;

    // override this to correct a bug so arguments can be passed to

    // the Target class

    protected void startUp(String targetName) {

        List<String> argList = new ArrayList<>(Arrays.asList(args));

        argList.add(0, targetName); // pre-pend so it becomes the first "app" arg

        // We need the class path that contains the path to jdk.test.lib.Asserts.

        argList.add(0, " -cp " + System.getProperty("test.class.path"));

        println("run args: " + argList);

        connect((String[]) argList.toArray(args));

        waitForVMStart();

    }

    TestNestmateAttr (String[] args) {

        super(args);

    }

    public static void main(String[] args) throws Throwable {

        origin = args[0];

        new TestNestmateAttr(args).startTests();

    }

    public void runTests() throws Exception {

        // Get Target into debuggable state

        BreakpointEvent bpe = startTo("Target", "breakpoint", "()V");

        EventRequestManager erm = vm().eventRequestManager();

        MethodEntryRequest mee = erm.createMethodEntryRequest();

        mee.addClassFilter("Target");

        mee.enable();

        // Allow application to complete and shut down

        listenUntilVMDisconnect();

        if (getExceptionCaught()) {

            throw new Exception("TestNestmateAttr: failed due to unexpected exception - check logs for details");

        }

        else if (!testFailed) {

            println("TestNestmateAttr: passed");

        } else {

            throw new Exception("TestNestmateAttr: failure reported - check log for details");

        }

    }

    // All the actual work is done from here once we see we've entered Target.allowRedefine()

    public void methodEntered(MethodEntryEvent event) {

        Method meth = event.location().method();

        if (!meth.name().equals("allowRedefine")) {

            return;

        }

        System.out.println("TestNestmateAttr: Testing original Host class from " + origin);

        String[] badTransforms;  // directories of bad classes

        String[] goodTransforms; // directories of good classes

        boolean testNestHostChanges = false;

        switch (origin) {

        case "Host":

            badTransforms = new String[] {

                "HostA" // add member

            };

            goodTransforms = new String[] {

                origin

            };

            break;

        case "HostA":

            badTransforms = new String[] {

                "Host",   // remove member

                "HostAB", // add member

                "HostB"   // change member

            };

            goodTransforms = new String[] {

                origin

            };

            testNestHostChanges = true;

            break;

        case "HostAB":

            badTransforms = new String[] {

                "HostA",   // remove member

                "HostABC", // add member

                "HostAC"   // change member

            };

            goodTransforms = new String[] {

                origin,

                "HostBA"  // reorder members

            };

            break;

        case "HostABC":

            badTransforms = new String[] {

                "HostAB",   // remove member

                "HostABCD", // add member

                "HostABD"   // change member

            };

            goodTransforms = new String[] {

                origin,

                "HostACB",  // reorder members

                "HostBAC",  // reorder members

                "HostBCA",  // reorder members

                "HostCAB",  // reorder members

                "HostCBA"   // reorder members

            };

            break;

        default: throw new Error("Unknown test directory: " + origin);

        }

        // Need to locate the type we will be trying to redefine in Target

        findReferenceTypes();

        try {

            // Compile and check bad transformations

            checkBadTransforms(_Host, badTransforms);

            // Compile and check good transformations

            checkGoodTransforms(_Host, goodTransforms);

            if (testNestHostChanges)

                checkNestHostChanges();

        }

        catch (Throwable t) {

            failure(t);

        }

    }

    // override to give exception details

    protected void failure(Throwable t) {

        super.failure(t.getMessage());

        t.printStackTrace(System.out);

    }

    // These are references to the types in Target

    // that we will be trying to redefine.

    ReferenceType _Host;

    ReferenceType _Host_A_nested;

    ReferenceType _Host_A_topLevel;

    void findReferenceTypes() {

        List<ReferenceType> classes = vm().allClasses();

        ClassLoaderReference cl = null; // track the main loader

        ReferenceType a1 = null;

        ReferenceType a2 = null;

        for (ReferenceType c : classes) {

            String name = c.name();

            if (name.equals("Host")) {

                _Host = c;

                cl = c.classLoader();

            }

            else if (name.equals("Host$A")) {

                if (a1 == null) {

                    a1 = c;

                } else if (a2 == null) {

                    a2 = c;

                }

                else {

                    assertTrue(false); // Too many Host$A classes found!

                }

            }

        }

        assertTrue(_Host != null);

        // The rest of this setup is only needed for the case

        // when we perform the checkNestHostChanges() test.

        if (origin.equals("HostA")) {

            assertTrue(a1 != null);

            assertTrue(a2 != null);

            if (a1.classLoader() == cl) {

                _Host_A_nested = a1;

                assertTrue(a2.classLoader() != cl);

                _Host_A_topLevel = a2;

            }

            else if (a2.classLoader() == cl) {

                _Host_A_nested = a2;

                assertTrue(a1.classLoader() != cl);

                _Host_A_topLevel = a1;

            }

            else {

                assertTrue(false); // Wrong classLoaders found

            }

        }

    }

    void checkNestHostChanges() throws Throwable {

        Map<ReferenceType, byte[]> map = new HashMap<>();

        // case 1: remove NestHost attribute

        //   - try to redefine nested Host$A with a top-level

        //     class called Host$A

        System.out.println("Trying bad retransform that removes the NestHost attribute");

        String name = "Host$A";

        // This is compiled as a top-level class: the $ in the name is not

        // significant to the compiler.

        String hostA = "public class " + name + " {}";

        byte[] bytes = InMemoryJavaCompiler.compile(name, hostA);

        map.put(_Host_A_nested, bytes);

        try {

            vm().redefineClasses(map);

            throw new Error("Retransformation to top-level class " + name +

                            " succeeded unexpectedly");

        }

        catch (UnsupportedOperationException uoe) {

            if (uoe.getMessage().contains("changes to class attribute not implemented")) {

                System.out.println("Got expected exception " + uoe);

            }

            else throw new Error("Wrong UnsupportedOperationException", uoe);

        }

        map.clear();

        // case 2: add NestHost attribute

        //  - This is tricky because the class with no NestHost attribute

        //    has to have the name of a nested class! But we know how to

        //    do that as we already created a top-level Host$A. So now

        //    we try to replace with a really nested Host$A.

        System.out.println("Trying bad retransform that adds the NestHost attribute");

        byte[] nestedBytes;

        File clsfile = new File(DEST + "/" + name + ".class");

        if (VERBOSE) System.out.println("Reading bytes from " + clsfile);

        try (FileInputStream str = new FileInputStream(clsfile)) {

            nestedBytes = NamedBuffer.loadBufferFromStream(str);

        }

        map.put(_Host_A_topLevel, nestedBytes);

        try {

            vm().redefineClasses(map);

            throw new Error("Retransformation to nested class " + name +

                            " succeeded unexpectedly");

        }

        catch (UnsupportedOperationException uoe) {

            if (uoe.getMessage().contains("changes to class attribute not implemented")) {

                System.out.println("Got expected exception " + uoe);

            }

            else throw new Error("Wrong UnsupportedOperationException", uoe);

        }

        map.clear();

        // case 3: replace the NestHost attribute

        //  - the easiest way (perhaps only reasonable way) to do this

        //    is to search for the Utf8 entry used by the Constant_ClassRef,

        //    set in the NestHost attribute, and edit it to refer to a different

        //    name. We reuse nestedBytes from above.

        System.out.println("Trying bad retransform that changes the NestHost attribute");

        int utf8Entry_length = 7;

        boolean found = false;

        for (int i = 0; i < nestedBytes.length - utf8Entry_length; i++) {

            if (nestedBytes[i] == 1 &&   // utf8 tag

                nestedBytes[i+1] == 0 && // msb of length

                nestedBytes[i+2] == 4 && // lsb of length

                nestedBytes[i+3] == (byte) 'H' &&

                nestedBytes[i+4] == (byte) 'o' &&

                nestedBytes[i+5] == (byte) 's' &&

                nestedBytes[i+6] == (byte) 't') {

                if (VERBOSE) System.out.println("Appear to have found Host utf8 entry starting at " + i);

                nestedBytes[i+3] = (byte) 'G';

                found = true;

                break;

            }

        }

        if (!found)

            throw new Error("Could not locate 'Host' name in byte array");

        map.put(_Host_A_nested, nestedBytes);

        try {

            vm().redefineClasses(map);

            throw new Error("Retransformation to modified nested class" +

                            " succeeded unexpectedly");

        }

        catch (UnsupportedOperationException uoe) {

            if (uoe.getMessage().contains("changes to class attribute not implemented")) {

                System.out.println("Got expected exception " + uoe);

            }

            else throw new Error("Wrong UnsupportedOperationException", uoe);

        }

    }

    void checkGoodTransforms(ReferenceType c, String[] dirs) throws Throwable {

        // To verify the redefinition actually took place we will invoke the

        // Host.getID method and check the result. To do that we need to find the

        // main thread in the target VM. We don't check that "(new Host()).m()"

        // returns 2 due to the complexity of setting that up via JDI.

        ThreadReference main = null;

        List<ThreadReference> threads = vm().allThreads();

        for (ThreadReference t : threads) {

            if (t.name().equals("main")) {

                main = t;

                break;

            }

        }

        assertTrue(main != null);

        // Now find the method

        Method getID = null;

        List<Method> methods = _Host.methodsByName("getID");