/*

 * Copyright (c) 2009, 2016, 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

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 */

/* @test

 * @summary white-box testing of method handle sub-primitives

 * @modules java.base/java.lang.invoke:open

 * @run junit test.java.lang.invoke.PrivateInvokeTest

 */

package test.java.lang.invoke;

import java.lang.invoke.*;

import static java.lang.invoke.MethodHandles.*;

import static java.lang.invoke.MethodType.*;

import java.lang.reflect.*;

import java.util.ArrayList;

import java.util.Arrays;

import org.junit.*;

import static org.junit.Assert.*;

public class PrivateInvokeTest {

    // Utility functions

    private static final Lookup LOOKUP = lookup();

    private static final Class<?> THIS_CLASS = PrivateInvokeTest.class;

    private static final int

            REF_NONE                    = 0,  // null value

            REF_getField                = 1,

            REF_getStatic               = 2,

            REF_putField                = 3,

            REF_putStatic               = 4,

            REF_invokeVirtual           = 5,

            REF_invokeStatic            = 6,

            REF_invokeSpecial           = 7,

            REF_newInvokeSpecial        = 8,

            REF_invokeInterface         = 9,

            REF_LIMIT                  = 10,

            REF_MH_invokeBasic         = REF_NONE;;

    private static final String[] REF_KIND_NAMES = {

        "MH::invokeBasic",

        "REF_getField", "REF_getStatic", "REF_putField", "REF_putStatic",

        "REF_invokeVirtual", "REF_invokeStatic", "REF_invokeSpecial",

        "REF_newInvokeSpecial", "REF_invokeInterface"

    };

    private int verbose;

    //{ verbose = 99; }  // for debugging

    {

        String vstr = System.getProperty(THIS_CLASS.getSimpleName()+".verbose");

        if (vstr == null)

            vstr = System.getProperty(THIS_CLASS.getName()+".verbose");

        if (vstr == null)

            vstr = System.getProperty("test.verbose");

        if (vstr != null)  verbose = Integer.parseInt(vstr);

    }

    private static int referenceKind(Method m) {

        if (Modifier.isStatic(m.getModifiers()))

            return REF_invokeStatic;

        else if (m.getDeclaringClass().isInterface())

            return REF_invokeInterface;

        else if (Modifier.isFinal(m.getModifiers()) ||

            Modifier.isFinal(m.getDeclaringClass().getModifiers()))

            return REF_invokeSpecial;

        else

            return REF_invokeVirtual;

    }

    private static MethodType basicType(MethodType mtype) {

        MethodType btype = mtype.erase();

        if (btype.hasPrimitives()) {

            for (int i = -1; i < mtype.parameterCount(); i++) {

                Class<?> type = (i < 0 ? mtype.returnType() : mtype.parameterType(i));

                if (type == boolean.class ||

                    type == byte.class ||

                    type == char.class ||

                    type == short.class) {

                    type = int.class;

                    if (i < 0)

                        btype = btype.changeReturnType(type);

                    else

                        btype = btype.changeParameterType(i, type);

                }

            }

        }

        return btype;

    }

    private static Method getMethod(Class<?> defc, String name, Class<?>... ptypes) {

        try {

            return defc.getDeclaredMethod(name, ptypes);

        } catch (NoSuchMethodException ex) {

        }

        try {

            return defc.getMethod(name, ptypes);

        } catch (NoSuchMethodException ex) {

            throw new IllegalArgumentException(ex);

        }

    }

    private static MethodHandle unreflect(Method m) {

        try {

            MethodHandle mh = LOOKUP.unreflect(m);

            if (Modifier.isTransient(m.getModifiers()))

                mh = mh.asFixedArity();  // remove varargs wrapper

            return mh;

        } catch (IllegalAccessException ex) {

            throw new IllegalArgumentException(ex);

        }

    }

    private static final Lookup DIRECT_INVOKER_LOOKUP;

    private static final Class<?> MEMBER_NAME_CLASS;

    private static final MethodHandle MH_INTERNAL_MEMBER_NAME;

    private static final MethodHandle MH_DEBUG_STRING;

    static {

        try {

            // This is white box testing.  Use reflection to grab private implementation bits.

            String magicName = "IMPL_LOOKUP";

            Field magicLookup = MethodHandles.Lookup.class.getDeclaredField(magicName);

            // This unit test will fail if a security manager is installed.

            magicLookup.setAccessible(true);

            // Forbidden fruit...

            DIRECT_INVOKER_LOOKUP = (Lookup) magicLookup.get(null);

            MEMBER_NAME_CLASS = Class.forName("java.lang.invoke.MemberName", false, MethodHandle.class.getClassLoader());

            MH_INTERNAL_MEMBER_NAME = DIRECT_INVOKER_LOOKUP

                    .findVirtual(MethodHandle.class, "internalMemberName", methodType(MEMBER_NAME_CLASS))

                    .asType(methodType(Object.class, MethodHandle.class));

            MH_DEBUG_STRING = DIRECT_INVOKER_LOOKUP

                    .findVirtual(MethodHandle.class, "debugString", methodType(String.class));

        } catch (ReflectiveOperationException ex) {

            throw new Error(ex);

        }

    }

    private Object internalMemberName(MethodHandle mh) {

        try {

            return MH_INTERNAL_MEMBER_NAME.invokeExact(mh);

        } catch (Throwable ex) {

            throw new Error(ex);

        }

    }

    private String debugString(MethodHandle mh) {

        try {

            return (String) MH_DEBUG_STRING.invokeExact(mh);

        } catch (Throwable ex) {

            throw new Error(ex);

        }

    }

    private static MethodHandle directInvoker(int refKind, MethodType mtype) {

        return directInvoker(REF_KIND_NAMES[refKind], mtype);

    }

    private static MethodHandle directInvoker(String name, MethodType mtype) {

        boolean isStatic;

        mtype = mtype.erase();

        if (name.startsWith("MH::")) {

            isStatic = false;

            name = strip("MH::", name);

        } else if (name.startsWith("REF_")) {

            isStatic = true;

            name = strip("REF_", name);

            if (name.startsWith("invoke"))

                name = "linkTo"+strip("invoke", name);

            mtype = mtype.appendParameterTypes(MEMBER_NAME_CLASS);

        } else {

            throw new AssertionError("name="+name);

        }

        //System.out.println("directInvoker = "+name+mtype);

        try {

            if (isStatic)

                return DIRECT_INVOKER_LOOKUP

                        .findStatic(MethodHandle.class, name, mtype);

            else

                return DIRECT_INVOKER_LOOKUP

                        .findVirtual(MethodHandle.class, name, mtype);

        } catch (ReflectiveOperationException ex) {

            throw new IllegalArgumentException(ex);

        }

    }

    private Object invokeWithArguments(Method m, Object... args) {

        Object recv = null;

        if (!Modifier.isStatic(m.getModifiers())) {

            recv = args[0];

            args = pop(1, args);

        }

        try {

            return m.invoke(recv, args);

        } catch (IllegalAccessException|IllegalArgumentException|InvocationTargetException ex) {

            throw new IllegalArgumentException(ex);

        }

    }

    private Object invokeWithArguments(MethodHandle mh, Object... args) {

        try {

            return mh.invokeWithArguments(args);

        } catch (Throwable ex) {

            throw new IllegalArgumentException(ex);

        }

    }

    private int counter;

    private Object makeArgument(Class<?> type) {

        final String cname = type.getSimpleName();

        final int n = ++counter;

        final int nn = (n << 10) + 13;

        if (type.isAssignableFrom(String.class)) {

            return "<"+cname+"#"+nn+">";

        }

        if (type == THIS_CLASS)  return this.withCounter(nn);

        if (type == Integer.class   || type == int.class)     return nn;

        if (type == Character.class || type == char.class)    return (char)(n % 100+' ');

        if (type == Byte.class      || type == byte.class)    return (byte)-(n % 100);

        if (type == Long.class      || type == long.class)    return (long)nn;

        throw new IllegalArgumentException("don't know how to make argument of type: "+type);

    }

    private Object[] makeArguments(Class<?>... ptypes) {

        Object[] args = new Object[ptypes.length];

        for (int i = 0; i < args.length; i++)

            args[i] = makeArgument(ptypes[i]);

        return args;

    }

    private Object[] makeArguments(MethodType mtype) {

        return makeArguments(mtype.parameterArray());

    }

    private Object[] pop(int n, Object[] args) {

        if (n >= 0)

            return Arrays.copyOfRange(args, n, args.length);

        else

            return Arrays.copyOfRange(args, 0, args.length+n);

    }

    private Object[] pushAtFront(Object arg1, Object[] args) {

        Object[] res = new Object[1+args.length];

        res[0] = arg1;

        System.arraycopy(args, 0, res, 1, args.length);

        return res;

    }

    private Object[] pushAtBack(Object[] args, Object argN) {

        Object[] res = new Object[1+args.length];

        System.arraycopy(args, 0, res, 0, args.length);

        res[args.length] = argN;

        return res;

    }

    private static String strip(String prefix, String s) {

        assert(s.startsWith(prefix));

        return s.substring(prefix.length());

    }

    private final int[] refKindTestCounts = new int[REF_KIND_NAMES.length];

    @After

    public void printCounts() {

        ArrayList<String> zeroes = new ArrayList<>();

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

            final int count = refKindTestCounts[i];

            final String name = REF_KIND_NAMES[i];

            if (count == 0) {

                if (name != null)  zeroes.add(name);

                continue;

            }

            if (verbose >= 0)

                System.out.println("test count for "+name+" : "+count);

            else if (name != null)

                zeroes.add(name);

        }

        if (verbose >= 0)

            System.out.println("test counts zero for "+zeroes);

    }

    // Test subjects

    public static String makeString(Object x) { return "makeString("+x+")"; }

    public static String dupString(String x) { return "("+x+"+"+x+")"; }

    public static String intString(int x) { return "intString("+x+")"; }

    public static String byteString(byte x) { return "byteString("+x+")"; }

    public static String longString(String x, long y, String z) { return "longString("+x+y+z+")"; }

    public final String toString() {

        return "<"+getClass().getSimpleName()+"#"+counter+">";

    }

    public final String hello() { return "hello from "+this; }

    private PrivateInvokeTest withCounter(int counter) {

        PrivateInvokeTest res = new PrivateInvokeTest();

        res.counter = counter;

        return res;

    }

    public static void main(String... av) throws Throwable {

        new PrivateInvokeTest().run();

    }

    public void run() throws Throwable {

        testFirst();

        testInvokeDirect();

    }

    @Test

    public void testFirst() throws Throwable {

        if (true)  return;  // nothing here

        try {

            System.out.println("start of testFirst");

        } finally {

            System.out.println("end of testFirst");

        }

    }

    @Test

    public void testInvokeDirect() {

        testInvokeDirect(getMethod(THIS_CLASS, "hello"));

        testInvokeDirect(getMethod(Object.class, "toString"));

        testInvokeDirect(getMethod(Comparable.class, "compareTo", Object.class));

        testInvokeDirect(getMethod(THIS_CLASS, "makeString", Object.class));

        testInvokeDirect(getMethod(THIS_CLASS, "dupString", String.class));

        testInvokeDirect(getMethod(THIS_CLASS, "intString", int.class));

        testInvokeDirect(getMethod(THIS_CLASS, "byteString", byte.class));

        testInvokeDirect(getMethod(THIS_CLASS, "longString", String.class, long.class, String.class));

    }

    void testInvokeDirect(Method m) {

        final int refKind = referenceKind(m);

        testInvokeDirect(m, refKind);

        testInvokeDirect(m, REF_MH_invokeBasic);

    }

    void testInvokeDirect(Method m, int refKind) {

        if (verbose >= 1)

            System.out.println("testInvoke m="+m+" : "+REF_KIND_NAMES[refKind]);

        final MethodHandle mh = unreflect(m);

        Object[] args = makeArguments(mh.type());

        Object res1 = invokeWithArguments(m, args);

        // res1 comes from java.lang.reflect.Method::invoke

        if (verbose >= 1)

            System.out.println("m"+Arrays.asList(args)+" => "+res1);

        // res2 comes from java.lang.invoke.MethodHandle::invoke

        Object res2 = invokeWithArguments(mh, args);

        assertEquals(res1, res2);

        MethodType mtype = mh.type();

        testInvokeVia("DMH invoker", refKind, directInvoker(refKind, mtype), mh, res1, args);

        MethodType etype = mtype.erase();

        if (etype != mtype) {

            // Try a detuned invoker.

            testInvokeVia("erased DMH invoker", refKind, directInvoker(refKind, etype), mh, res1, args);

        }

        MethodType btype = basicType(mtype);

        if (btype != mtype && btype != etype) {

            // Try a detuned invoker.

            testInvokeVia("basic DMH invoker", refKind, directInvoker(refKind, btype), mh, res1, args);

        }

        if (false) {

            // this can crash the JVM

            testInvokeVia("generic DMH invoker", refKind, directInvoker(refKind, mtype.generic()), mh, res1, args);

        }

        refKindTestCounts[refKind] += 1;

    }

    void testInvokeVia(String kind, int refKind, MethodHandle invoker, MethodHandle mh, Object res1, Object... args) {

        Object[] args1;

        if (refKind == REF_MH_invokeBasic)

            args1 = pushAtFront(mh, args);

        else

            args1 = pushAtBack(args, internalMemberName(mh));

        if (verbose >= 2) {

            System.out.println(kind+" invoker="+invoker+" mh="+debugString(mh)+" args="+Arrays.asList(args1));

        }

        Object res3 = invokeWithArguments(invoker, args1);

        assertEquals(res1, res3);

    }

}