/*

 * Copyright (c) 2008, 2013, 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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.

 */

package java.lang.invoke;

import sun.invoke.util.BytecodeDescriptor;

import sun.invoke.util.VerifyAccess;

import java.lang.reflect.Constructor;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import java.lang.reflect.Member;

import java.lang.reflect.Modifier;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.Iterator;

import java.util.List;

import static java.lang.invoke.MethodHandleNatives.Constants.*;

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

import java.util.Objects;

/**

 * A {@code MemberName} is a compact symbolic datum which fully characterizes

 * a method or field reference.

 * A member name refers to a field, method, constructor, or member type.

 * Every member name has a simple name (a string) and a type (either a Class or MethodType).

 * A member name may also have a non-null declaring class, or it may be simply

 * a naked name/type pair.

 * A member name may also have non-zero modifier flags.

 * Finally, a member name may be either resolved or unresolved.

 * If it is resolved, the existence of the named

 * <p>

 * Whether resolved or not, a member name provides no access rights or

 * invocation capability to its possessor.  It is merely a compact

 * representation of all symbolic information necessary to link to

 * and properly use the named member.

 * <p>

 * When resolved, a member name's internal implementation may include references to JVM metadata.

 * This representation is stateless and only decriptive.

 * It provides no private information and no capability to use the member.

 * <p>

 * By contrast, a {@linkplain java.lang.reflect.Method} contains fuller information

 * about the internals of a method (except its bytecodes) and also

 * allows invocation.  A MemberName is much lighter than a Method,

 * since it contains about 7 fields to the 16 of Method (plus its sub-arrays),

 * and those seven fields omit much of the information in Method.

 * @author jrose

 */

/*non-public*/ final class MemberName implements Member, Cloneable {

    private Class<?> clazz;       // class in which the method is defined

    private String   name;        // may be null if not yet materialized

    private Object   type;        // may be null if not yet materialized

    private int      flags;       // modifier bits; see reflect.Modifier

    //@Injected JVM_Method* vmtarget;

    //@Injected int         vmindex;

    private Object   resolution;  // if null, this guy is resolved

    /** Return the declaring class of this member.

     *  In the case of a bare name and type, the declaring class will be null.

     */

    public Class<?> getDeclaringClass() {

        return clazz;

    }

    /** Utility method producing the class loader of the declaring class. */

    public ClassLoader getClassLoader() {

        return clazz.getClassLoader();

    }

    /** Return the simple name of this member.

     *  For a type, it is the same as {@link Class#getSimpleName}.

     *  For a method or field, it is the simple name of the member.

     *  For a constructor, it is always {@code "<init>"}.

     */

    public String getName() {

        if (name == null) {

            expandFromVM();

            if (name == null) {

                return null;

            }

        }

        return name;

    }

    public MethodType getMethodOrFieldType() {

        if (isInvocable())

            return getMethodType();

        if (isGetter())

            return MethodType.methodType(getFieldType());

        if (isSetter())

            return MethodType.methodType(void.class, getFieldType());

        throw new InternalError("not a method or field: "+this);

    }

    /** Return the declared type of this member, which

     *  must be a method or constructor.

     */

    public MethodType getMethodType() {

        if (type == null) {

            expandFromVM();

            if (type == null) {

                return null;

            }

        }

        if (!isInvocable()) {

            throw newIllegalArgumentException("not invocable, no method type");

        }

        {

            // Get a snapshot of type which doesn't get changed by racing threads.

            final Object type = this.type;

            if (type instanceof MethodType) {

                return (MethodType) type;

            }

        }

        // type is not a MethodType yet.  Convert it thread-safely.

        synchronized (this) {

            if (type instanceof String) {

                String sig = (String) type;

                MethodType res = MethodType.fromMethodDescriptorString(sig, getClassLoader());

                type = res;

            } else if (type instanceof Object[]) {

                Object[] typeInfo = (Object[]) type;

                Class<?>[] ptypes = (Class<?>[]) typeInfo[1];

                Class<?> rtype = (Class<?>) typeInfo[0];

                MethodType res = MethodType.methodType(rtype, ptypes);

                type = res;

            }

            // Make sure type is a MethodType for racing threads.

            assert type instanceof MethodType : "bad method type " + type;

        }

        return (MethodType) type;

    }

    /** Return the actual type under which this method or constructor must be invoked.

     *  For non-static methods or constructors, this is the type with a leading parameter,

     *  a reference to declaring class.  For static methods, it is the same as the declared type.

     */

    public MethodType getInvocationType() {

        MethodType itype = getMethodOrFieldType();

        if (isConstructor() && getReferenceKind() == REF_newInvokeSpecial)

            return itype.changeReturnType(clazz);

        if (!isStatic())

            return itype.insertParameterTypes(0, clazz);

        return itype;

    }

    /** Utility method producing the parameter types of the method type. */

    public Class<?>[] getParameterTypes() {

        return getMethodType().parameterArray();

    }

    /** Utility method producing the return type of the method type. */

    public Class<?> getReturnType() {

        return getMethodType().returnType();

    }

    /** Return the declared type of this member, which

     *  must be a field or type.

     *  If it is a type member, that type itself is returned.

     */

    public Class<?> getFieldType() {

        if (type == null) {

            expandFromVM();

            if (type == null) {

                return null;

            }

        }

        if (isInvocable()) {

            throw newIllegalArgumentException("not a field or nested class, no simple type");

        }

        {

            // Get a snapshot of type which doesn't get changed by racing threads.

            final Object type = this.type;

            if (type instanceof Class<?>) {

                return (Class<?>) type;

            }

        }

        // type is not a Class yet.  Convert it thread-safely.

        synchronized (this) {

            if (type instanceof String) {

                String sig = (String) type;

                MethodType mtype = MethodType.fromMethodDescriptorString("()"+sig, getClassLoader());

                Class<?> res = mtype.returnType();

                type = res;

            }

            // Make sure type is a Class for racing threads.

            assert type instanceof Class<?> : "bad field type " + type;

        }

        return (Class<?>) type;

    }

    /** Utility method to produce either the method type or field type of this member. */

    public Object getType() {

        return (isInvocable() ? getMethodType() : getFieldType());

    }

    /** Utility method to produce the signature of this member,

     *  used within the class file format to describe its type.

     */

    public String getSignature() {

        if (type == null) {

            expandFromVM();

            if (type == null) {

                return null;

            }

        }

        if (isInvocable())

            return BytecodeDescriptor.unparse(getMethodType());

        else

            return BytecodeDescriptor.unparse(getFieldType());

    }

    /** Return the modifier flags of this member.

     *  @see java.lang.reflect.Modifier

     */

    public int getModifiers() {

        return (flags & RECOGNIZED_MODIFIERS);

    }

    /** Return the reference kind of this member, or zero if none.

     */

    public byte getReferenceKind() {

        return (byte) ((flags >>> MN_REFERENCE_KIND_SHIFT) & MN_REFERENCE_KIND_MASK);

    }

    private boolean referenceKindIsConsistent() {

        byte refKind = getReferenceKind();

        if (refKind == REF_NONE)  return isType();

        if (isField()) {

            assert(staticIsConsistent());

            assert(MethodHandleNatives.refKindIsField(refKind));

        } else if (isConstructor()) {

            assert(refKind == REF_newInvokeSpecial || refKind == REF_invokeSpecial);

        } else if (isMethod()) {

            assert(staticIsConsistent());

            assert(MethodHandleNatives.refKindIsMethod(refKind));

            if (clazz.isInterface())

                assert(refKind == REF_invokeInterface ||

                       refKind == REF_invokeStatic    ||

                       refKind == REF_invokeSpecial   ||

                       refKind == REF_invokeVirtual && isObjectPublicMethod());

        } else {

            assert(false);

        }

        return true;

    }

    private boolean isObjectPublicMethod() {

        if (clazz == Object.class)  return true;

        MethodType mtype = getMethodType();

        if (name.equals("toString") && mtype.returnType() == String.class && mtype.parameterCount() == 0)

            return true;

        if (name.equals("hashCode") && mtype.returnType() == int.class && mtype.parameterCount() == 0)

            return true;

        if (name.equals("equals") && mtype.returnType() == boolean.class && mtype.parameterCount() == 1 && mtype.parameterType(0) == Object.class)

            return true;

        return false;

    }

    /*non-public*/ boolean referenceKindIsConsistentWith(int originalRefKind) {

        int refKind = getReferenceKind();

        if (refKind == originalRefKind)  return true;

        switch (originalRefKind) {

        case REF_invokeInterface:

            // Looking up an interface method, can get (e.g.) Object.hashCode

            assert(refKind == REF_invokeVirtual ||

                   refKind == REF_invokeSpecial) : this;

            return true;

        case REF_invokeVirtual:

        case REF_newInvokeSpecial:

            // Looked up a virtual, can get (e.g.) final String.hashCode.

            assert(refKind == REF_invokeSpecial) : this;

            return true;

        }

        assert(false) : this+" != "+MethodHandleNatives.refKindName((byte)originalRefKind);

        return true;

    }

    private boolean staticIsConsistent() {

        byte refKind = getReferenceKind();

        return MethodHandleNatives.refKindIsStatic(refKind) == isStatic() || getModifiers() == 0;

    }

    private boolean vminfoIsConsistent() {

        byte refKind = getReferenceKind();

        assert(isResolved());  // else don't call

        Object vminfo = MethodHandleNatives.getMemberVMInfo(this);

        assert(vminfo instanceof Object[]);

        long vmindex = (Long) ((Object[])vminfo)[0];

        Object vmtarget = ((Object[])vminfo)[1];

        if (MethodHandleNatives.refKindIsField(refKind)) {

            assert(vmindex >= 0) : vmindex + ":" + this;

            assert(vmtarget instanceof Class);

        } else {

            if (MethodHandleNatives.refKindDoesDispatch(refKind))

                assert(vmindex >= 0) : vmindex + ":" + this;

            else

                assert(vmindex < 0) : vmindex;

            assert(vmtarget instanceof MemberName) : vmtarget + " in " + this;

        }

        return true;

    }

    private MemberName changeReferenceKind(byte refKind, byte oldKind) {

        assert(getReferenceKind() == oldKind);

        assert(MethodHandleNatives.refKindIsValid(refKind));

        flags += (((int)refKind - oldKind) << MN_REFERENCE_KIND_SHIFT);

//        if (isConstructor() && refKind != REF_newInvokeSpecial)

//            flags += (IS_METHOD - IS_CONSTRUCTOR);

//        else if (refKind == REF_newInvokeSpecial && isMethod())

//            flags += (IS_CONSTRUCTOR - IS_METHOD);

        return this;

    }

    private boolean testFlags(int mask, int value) {

        return (flags & mask) == value;

    }

    private boolean testAllFlags(int mask) {

        return testFlags(mask, mask);

    }

    private boolean testAnyFlags(int mask) {

        return !testFlags(mask, 0);

    }

    /** Utility method to query if this member is a method handle invocation (invoke or invokeExact). */

    public boolean isMethodHandleInvoke() {

        final int bits = MH_INVOKE_MODS;

        final int negs = Modifier.STATIC;

        if (testFlags(bits | negs, bits) &&

            clazz == MethodHandle.class) {

            return isMethodHandleInvokeName(name);

        }

        return false;

    }

    public static boolean isMethodHandleInvokeName(String name) {

        return name.equals("invoke") || name.equals("invokeExact");

    }

    private static final int MH_INVOKE_MODS = Modifier.NATIVE | Modifier.FINAL | Modifier.PUBLIC;

    /** Utility method to query the modifier flags of this member. */

    public boolean isStatic() {

        return Modifier.isStatic(flags);

    }

    /** Utility method to query the modifier flags of this member. */

    public boolean isPublic() {

        return Modifier.isPublic(flags);

    }

    /** Utility method to query the modifier flags of this member. */

    public boolean isPrivate() {

        return Modifier.isPrivate(flags);

    }

    /** Utility method to query the modifier flags of this member. */

    public boolean isProtected() {

        return Modifier.isProtected(flags);

    }

    /** Utility method to query the modifier flags of this member. */

    public boolean isFinal() {

        return Modifier.isFinal(flags);

    }

    /** Utility method to query whether this member or its defining class is final. */

    public boolean canBeStaticallyBound() {

        return Modifier.isFinal(flags | clazz.getModifiers());

    }

    /** Utility method to query the modifier flags of this member. */

    public boolean isVolatile() {

        return Modifier.isVolatile(flags);

    }

    /** Utility method to query the modifier flags of this member. */

    public boolean isAbstract() {

        return Modifier.isAbstract(flags);

    }

    /** Utility method to query the modifier flags of this member. */

    public boolean isNative() {

        return Modifier.isNative(flags);

    }

    // let the rest (native, volatile, transient, etc.) be tested via Modifier.isFoo

    // unofficial modifier flags, used by HotSpot:

    static final int BRIDGE    = 0x00000040;

    static final int VARARGS   = 0x00000080;

    static final int SYNTHETIC = 0x00001000;

    static final int ANNOTATION= 0x00002000;

    static final int ENUM      = 0x00004000;

    /** Utility method to query the modifier flags of this member; returns false if the member is not a method. */

    public boolean isBridge() {

        return testAllFlags(IS_METHOD | BRIDGE);

    }

    /** Utility method to query the modifier flags of this member; returns false if the member is not a method. */

    public boolean isVarargs() {

        return testAllFlags(VARARGS) && isInvocable();

    }

    /** Utility method to query the modifier flags of this member; returns false if the member is not a method. */

    public boolean isSynthetic() {

        return testAllFlags(SYNTHETIC);

    }

    static final String CONSTRUCTOR_NAME = "<init>";  // the ever-popular

    // modifiers exported by the JVM:

    static final int RECOGNIZED_MODIFIERS = 0xFFFF;

    // private flags, not part of RECOGNIZED_MODIFIERS:

    static final int

            IS_METHOD        = MN_IS_METHOD,        // method (not constructor)

            IS_CONSTRUCTOR   = MN_IS_CONSTRUCTOR,   // constructor

            IS_FIELD         = MN_IS_FIELD,         // field

            IS_TYPE          = MN_IS_TYPE,          // nested type

            CALLER_SENSITIVE = MN_CALLER_SENSITIVE; // @CallerSensitive annotation detected

    static final int ALL_ACCESS = Modifier.PUBLIC | Modifier.PRIVATE | Modifier.PROTECTED;

    static final int ALL_KINDS = IS_METHOD | IS_CONSTRUCTOR | IS_FIELD | IS_TYPE;

    static final int IS_INVOCABLE = IS_METHOD | IS_CONSTRUCTOR;

    static final int IS_FIELD_OR_METHOD = IS_METHOD | IS_FIELD;

    static final int SEARCH_ALL_SUPERS = MN_SEARCH_SUPERCLASSES | MN_SEARCH_INTERFACES;

    /** Utility method to query whether this member is a method or constructor. */

    public boolean isInvocable() {

        return testAnyFlags(IS_INVOCABLE);

    }

    /** Utility method to query whether this member is a method, constructor, or field. */

    public boolean isFieldOrMethod() {

        return testAnyFlags(IS_FIELD_OR_METHOD);

    }

    /** Query whether this member is a method. */

    public boolean isMethod() {

        return testAllFlags(IS_METHOD);

    }

    /** Query whether this member is a constructor. */

    public boolean isConstructor() {

        return testAllFlags(IS_CONSTRUCTOR);

    }

    /** Query whether this member is a field. */

    public boolean isField() {

        return testAllFlags(IS_FIELD);

    }

    /** Query whether this member is a type. */

    public boolean isType() {

        return testAllFlags(IS_TYPE);

    }

    /** Utility method to query whether this member is neither public, private, nor protected. */

    public boolean isPackage() {

        return !testAnyFlags(ALL_ACCESS);

    }

    /** Query whether this member has a CallerSensitive annotation. */

    public boolean isCallerSensitive() {

        return testAllFlags(CALLER_SENSITIVE);

    }

    /** Utility method to query whether this member is accessible from a given lookup class. */

    public boolean isAccessibleFrom(Class<?> lookupClass) {

        return VerifyAccess.isMemberAccessible(this.getDeclaringClass(), this.getDeclaringClass(), flags,

                                               lookupClass, ALL_ACCESS|MethodHandles.Lookup.PACKAGE);

    }

    /** Initialize a query.   It is not resolved. */

    private void init(Class<?> defClass, String name, Object type, int flags) {

        // defining class is allowed to be null (for a naked name/type pair)

        //name.toString();  // null check

        //type.equals(type);  // null check

        // fill in fields:

        this.clazz = defClass;

        this.name = name;

        this.type = type;

        this.flags = flags;

        assert(testAnyFlags(ALL_KINDS));

        assert(this.resolution == null);  // nobody should have touched this yet

        //assert(referenceKindIsConsistent());  // do this after resolution

    }

    /**

     * Calls down to the VM to fill in the fields.  This method is

     * synchronized to avoid racing calls.

     */

    private void expandFromVM() {

        if (type != null) {

            return;

        }

        if (!isResolved()) {

            return;

        }

        MethodHandleNatives.expand(this);

    }

    // Capturing information from the Core Reflection API:

    private static int flagsMods(int flags, int mods, byte refKind) {

        assert((flags & RECOGNIZED_MODIFIERS) == 0);

        assert((mods & ~RECOGNIZED_MODIFIERS) == 0);

        assert((refKind & ~MN_REFERENCE_KIND_MASK) == 0);

        return flags | mods | (refKind << MN_REFERENCE_KIND_SHIFT);

    }

    /** Create a name for the given reflected method.  The resulting name will be in a resolved state. */

    public MemberName(Method m) {

        this(m, false);

    }

    @SuppressWarnings("LeakingThisInConstructor")

    public MemberName(Method m, boolean wantSpecial) {

        m.getClass();  // NPE check

        // fill in vmtarget, vmindex while we have m in hand:

        MethodHandleNatives.init(this, m);

        if (clazz == null) {  // MHN.init failed

            if (m.getDeclaringClass() == MethodHandle.class &&

                isMethodHandleInvokeName(m.getName())) {

                // The JVM did not reify this signature-polymorphic instance.

                // Need a special case here.

                // See comments on MethodHandleNatives.linkMethod.

                MethodType type = MethodType.methodType(m.getReturnType(), m.getParameterTypes());

                int flags = flagsMods(IS_METHOD, m.getModifiers(), REF_invokeVirtual);

                init(MethodHandle.class, m.getName(), type, flags);

                if (isMethodHandleInvoke())

                    return;

            }

            throw new LinkageError(m.toString());

        }

        assert(isResolved() && this.clazz != null);

        this.name = m.getName();

        if (this.type == null)

            this.type = new Object[] { m.getReturnType(), m.getParameterTypes() };

        if (wantSpecial) {

            if (isAbstract())

                throw new AbstractMethodError(this.toString());

            if (getReferenceKind() == REF_invokeVirtual)

                changeReferenceKind(REF_invokeSpecial, REF_invokeVirtual);

            else if (getReferenceKind() == REF_invokeInterface)

                // invokeSpecial on a default method

                changeReferenceKind(REF_invokeSpecial, REF_invokeInterface);

        }

    }

    public MemberName asSpecial() {

        switch (getReferenceKind()) {

        case REF_invokeSpecial:     return this;

        case REF_invokeVirtual:     return clone().changeReferenceKind(REF_invokeSpecial, REF_invokeVirtual);

        case REF_invokeInterface:   return clone().changeReferenceKind(REF_invokeSpecial, REF_invokeInterface);

        case REF_newInvokeSpecial:  return clone().changeReferenceKind(REF_invokeSpecial, REF_newInvokeSpecial);

        }

        throw new IllegalArgumentException(this.toString());

    }

    /** If this MN is not REF_newInvokeSpecial, return a clone with that ref. kind.

     *  In that case it must already be REF_invokeSpecial.

     */

    public MemberName asConstructor() {

        switch (getReferenceKind()) {

        case REF_invokeSpecial:     return clone().changeReferenceKind(REF_newInvokeSpecial, REF_invokeSpecial);

        case REF_newInvokeSpecial:  return this;

        }

        throw new IllegalArgumentException(this.toString());

    }

    /** If this MN is a REF_invokeSpecial, return a clone with the "normal" kind

     *  REF_invokeVirtual; also switch either to REF_invokeInterface if clazz.isInterface.

     *  The end result is to get a fully virtualized version of the MN.

     *  (Note that resolving in the JVM will sometimes devirtualize, changing

     *  REF_invokeVirtual of a final to REF_invokeSpecial, and REF_invokeInterface

     *  in some corner cases to either of the previous two; this transform

     *  undoes that change under the assumption that it occurred.)

     */

    public MemberName asNormalOriginal() {

        byte normalVirtual = clazz.isInterface() ? REF_invokeInterface : REF_invokeVirtual;

        byte refKind = getReferenceKind();

        byte newRefKind = refKind;

        MemberName result = this;

        switch (refKind) {

        case REF_invokeInterface:

        case REF_invokeVirtual:

        case REF_invokeSpecial:

            newRefKind = normalVirtual;

            break;

        }

        if (newRefKind == refKind)

            return this;

        result = clone().changeReferenceKind(newRefKind, refKind);

        assert(this.referenceKindIsConsistentWith(result.getReferenceKind()));

        return result;

    }

    /** Create a name for the given reflected constructor.  The resulting name will be in a resolved state. */

    @SuppressWarnings("LeakingThisInConstructor")

    public MemberName(Constructor<?> ctor) {

        ctor.getClass();  // NPE check

        // fill in vmtarget, vmindex while we have ctor in hand:

        MethodHandleNatives.init(this, ctor);

        assert(isResolved() && this.clazz != null);

        this.name = CONSTRUCTOR_NAME;

        if (this.type == null)

            this.type = new Object[] { void.class, ctor.getParameterTypes() };

    }

    /** Create a name for the given reflected field.  The resulting name will be in a resolved state.

     */

    public MemberName(Field fld) {

        this(fld, false);

    }

    @SuppressWarnings("LeakingThisInConstructor")

    public MemberName(Field fld, boolean makeSetter) {

        fld.getClass();  // NPE check

        // fill in vmtarget, vmindex while we have fld in hand:

        MethodHandleNatives.init(this, fld);

        assert(isResolved() && this.clazz != null);

        this.name = fld.getName();

        this.type = fld.getType();

        assert((REF_putStatic - REF_getStatic) == (REF_putField - REF_getField));

        byte refKind = this.getReferenceKind();

        assert(refKind == (isStatic() ? REF_getStatic : REF_getField));

        if (makeSetter) {

            changeReferenceKind((byte)(refKind + (REF_putStatic - REF_getStatic)), refKind);

        }

    }

    public boolean isGetter() {

        return MethodHandleNatives.refKindIsGetter(getReferenceKind());

    }

    public boolean isSetter() {

        return MethodHandleNatives.refKindIsSetter(getReferenceKind());

    }

    public MemberName asSetter() {

        byte refKind = getReferenceKind();

        assert(MethodHandleNatives.refKindIsGetter(refKind));

        assert((REF_putStatic - REF_getStatic) == (REF_putField - REF_getField));

        byte setterRefKind = (byte)(refKind + (REF_putField - REF_getField));

        return clone().changeReferenceKind(setterRefKind, refKind);

    }

    /** Create a name for the given class.  The resulting name will be in a resolved state. */

    public MemberName(Class<?> type) {

        init(type.getDeclaringClass(), type.getSimpleName(), type,

                flagsMods(IS_TYPE, type.getModifiers(), REF_NONE));

        initResolved(true);

    }

    /**

     * Create a name for a signature-polymorphic invoker.

     * This is a placeholder for a signature-polymorphic instance

     * (of MH.invokeExact, etc.) that the JVM does not reify.

     * See comments on {@link MethodHandleNatives#linkMethod}.

     */

    static MemberName makeMethodHandleInvoke(String name, MethodType type) {

        return makeMethodHandleInvoke(name, type, MH_INVOKE_MODS | SYNTHETIC);

    }

    static MemberName makeMethodHandleInvoke(String name, MethodType type, int mods) {

        MemberName mem = new MemberName(MethodHandle.class, name, type, REF_invokeVirtual);

        mem.flags |= mods;  // it's not resolved, but add these modifiers anyway

        assert(mem.isMethodHandleInvoke()) : mem;

        return mem;

    }

    // bare-bones constructor; the JVM will fill it in

    MemberName() { }

    // locally useful cloner

    @Override protected MemberName clone() {

        try {

            return (MemberName) super.clone();

        } catch (CloneNotSupportedException ex) {

            throw newInternalError(ex);

        }

     }

    /** Get the definition of this member name.

     *  This may be in a super-class of the declaring class of this member.

     */

    public MemberName getDefinition() {

        if (!isResolved())  throw new IllegalStateException("must be resolved: "+this);

        if (isType())  return this;

        MemberName res = this.clone();

        res.clazz = null;

        res.type = null;

        res.name = null;

        res.resolution = res;

        res.expandFromVM();

        assert(res.getName().equals(this.getName()));

        return res;

    }

    @Override

    public int hashCode() {

        return Objects.hash(clazz, getReferenceKind(), name, getType());

    }

    @Override

    public boolean equals(Object that) {

        return (that instanceof MemberName && this.equals((MemberName)that));

    }

    /** Decide if two member names have exactly the same symbolic content.

     *  Does not take into account any actual class members, so even if

     *  two member names resolve to the same actual member, they may

     *  be distinct references.

     */

    public boolean equals(MemberName that) {

        if (this == that)  return true;

        if (that == null)  return false;

        return this.clazz == that.clazz

                && this.getReferenceKind() == that.getReferenceKind()

                && Objects.equals(this.name, that.name)

                && Objects.equals(this.getType(), that.getType());

    }

    // Construction from symbolic parts, for queries:

    /** Create a field or type name from the given components:

     *  Declaring class, name, type, reference kind.

     *  The declaring class may be supplied as null if this is to be a bare name and type.

     *  The resulting name will in an unresolved state.

     */

    public MemberName(Class<?> defClass, String name, Class<?> type, byte refKind) {

        init(defClass, name, type, flagsMods(IS_FIELD, 0, refKind));

        initResolved(false);

    }

    /** Create a field or type name from the given components:  Declaring class, name, type.

     *  The declaring class may be supplied as null if this is to be a bare name and type.

     *  The modifier flags default to zero.

     *  The resulting name will in an unresolved state.

     */

    public MemberName(Class<?> defClass, String name, Class<?> type, Void unused) {

        this(defClass, name, type, REF_NONE);

        initResolved(false);

    }

    /** Create a method or constructor name from the given components:  Declaring class, name, type, modifiers.

     *  It will be a constructor if and only if the name is {@code "<init>"}.

     *  The declaring class may be supplied as null if this is to be a bare name and type.

     *  The last argument is optional, a boolean which requests REF_invokeSpecial.

     *  The resulting name will in an unresolved state.

     */

    public MemberName(Class<?> defClass, String name, MethodType type, byte refKind) {

        int initFlags = (name != null && name.equals(CONSTRUCTOR_NAME) ? IS_CONSTRUCTOR : IS_METHOD);

        init(defClass, name, type, flagsMods(initFlags, 0, refKind));

        initResolved(false);

    }

    /** Create a method, constructor, or field name from the given components:

     *  Reference kind, declaring class, name, type.

     */

    public MemberName(byte refKind, Class<?> defClass, String name, Object type) {

        int kindFlags;

        if (MethodHandleNatives.refKindIsField(refKind)) {

            kindFlags = IS_FIELD;

            if (!(type instanceof Class))

                throw newIllegalArgumentException("not a field type");

        } else if (MethodHandleNatives.refKindIsMethod(refKind)) {

            kindFlags = IS_METHOD;

            if (!(type instanceof MethodType))

                throw newIllegalArgumentException("not a method type");

        } else if (refKind == REF_newInvokeSpecial) {

            kindFlags = IS_CONSTRUCTOR;

            if (!(type instanceof MethodType) ||

                !CONSTRUCTOR_NAME.equals(name))

                throw newIllegalArgumentException("not a constructor type or name");

        } else {

            throw newIllegalArgumentException("bad reference kind "+refKind);

        }

        init(defClass, name, type, flagsMods(kindFlags, 0, refKind));

        initResolved(false);

    }

    /** Query whether this member name is resolved to a non-static, non-final method.

     */

    public boolean hasReceiverTypeDispatch() {

        return MethodHandleNatives.refKindDoesDispatch(getReferenceKind());

    }

    /** Query whether this member name is resolved.

     *  A resolved member name is one for which the JVM has found

     *  a method, constructor, field, or type binding corresponding exactly to the name.

     *  (Document?)

     */

    public boolean isResolved() {

        return resolution == null;

    }

    private void initResolved(boolean isResolved) {

        assert(this.resolution == null);  // not initialized yet!

        if (!isResolved)

            this.resolution = this;

        assert(isResolved() == isResolved);

    }

    void checkForTypeAlias() {

        if (isInvocable()) {

            MethodType type;

            if (this.type instanceof MethodType)

                type = (MethodType) this.type;

            else

                this.type = type = getMethodType();

            if (type.erase() == type)  return;

            if (VerifyAccess.isTypeVisible(type, clazz))  return;

            throw new LinkageError("bad method type alias: "+type+" not visible from "+clazz);

        } else {

            Class<?> type;

            if (this.type instanceof Class<?>)

                type = (Class<?>) this.type;

            else

                this.type = type = getFieldType();

            if (VerifyAccess.isTypeVisible(type, clazz))  return;

            throw new LinkageError("bad field type alias: "+type+" not visible from "+clazz);

        }

    }

    /** Produce a string form of this member name.

     *  For types, it is simply the type's own string (as reported by {@code toString}).

     *  For fields, it is {@code "DeclaringClass.name/type"}.

     *  For methods and constructors, it is {@code "DeclaringClass.name(ptype...)rtype"}.

     *  If the declaring class is null, the prefix {@code "DeclaringClass."} is omitted.

     *  If the member is unresolved, a prefix {@code "*."} is prepended.

     */

    @SuppressWarnings("LocalVariableHidesMemberVariable")

    @Override

    public String toString() {

        if (isType())

            return type.toString();  // class java.lang.String

        // else it is a field, method, or constructor

        StringBuilder buf = new StringBuilder();

        if (getDeclaringClass() != null) {

            buf.append(getName(clazz));

            buf.append('.');

        }

        String name = getName();

        buf.append(name == null ? "*" : name);

        Object type = getType();

        if (!isInvocable()) {

            buf.append('/');

            buf.append(type == null ? "*" : getName(type));

        } else {

            buf.append(type == null ? "(*)*" : getName(type));

        }

        byte refKind = getReferenceKind();

        if (refKind != REF_NONE) {

            buf.append('/');

            buf.append(MethodHandleNatives.refKindName(refKind));

        }

        //buf.append("#").append(System.identityHashCode(this));

        return buf.toString();

    }

    private static String getName(Object obj) {

        if (obj instanceof Class<?>)

            return ((Class<?>)obj).getName();

        return String.valueOf(obj);

    }

    public IllegalAccessException makeAccessException(String message, Object from) {

        message = message + ": "+ toString();

        if (from != null)  message += ", from " + from;

        return new IllegalAccessException(message);

    }

    private String message() {

        if (isResolved())

            return "no access";

        else if (isConstructor())

            return "no such constructor";

        else if (isMethod())

            return "no such method";

        else

            return "no such field";

    }

    public ReflectiveOperationException makeAccessException() {

        String message = message() + ": "+ toString();

        ReflectiveOperationException ex;

        if (isResolved() || !(resolution instanceof NoSuchMethodError ||

                              resolution instanceof NoSuchFieldError))

            ex = new IllegalAccessException(message);

        else if (isConstructor())

            ex = new NoSuchMethodException(message);

        else if (isMethod())

            ex = new NoSuchMethodException(message);

        else

            ex = new NoSuchFieldException(message);

        if (resolution instanceof Throwable)

            ex.initCause((Throwable) resolution);

        return ex;

    }

    /** Actually making a query requires an access check. */

    /*non-public*/ static Factory getFactory() {

        return Factory.INSTANCE;

    }

    /** A factory type for resolving member names with the help of the VM.

     *  TBD: Define access-safe public constructors for this factory.

     */

    /*non-public*/ static class Factory {

        private Factory() { } // singleton pattern

        static Factory INSTANCE = new Factory();

        private static int ALLOWED_FLAGS = ALL_KINDS;

        /// Queries

        List<MemberName> getMembers(Class<?> defc,

                String matchName, Object matchType,

                int matchFlags, Class<?> lookupClass) {

            matchFlags &= ALLOWED_FLAGS;

            String matchSig = null;

            if (matchType != null) {

                matchSig = BytecodeDescriptor.unparse(matchType);

                if (matchSig.startsWith("("))

                    matchFlags &= ~(ALL_KINDS & ~IS_INVOCABLE);

                else

                    matchFlags &= ~(ALL_KINDS & ~IS_FIELD);

            }

            final int BUF_MAX = 0x2000;

            int len1 = matchName == null ? 10 : matchType == null ? 4 : 1;

            MemberName[] buf = newMemberBuffer(len1);

            int totalCount = 0;

            ArrayList<MemberName[]> bufs = null;

            int bufCount = 0;

            for (;;) {

                bufCount = MethodHandleNatives.getMembers(defc,

                        matchName, matchSig, matchFlags,

                        lookupClass,

                        totalCount, buf);

                if (bufCount <= buf.length) {

                    if (bufCount < 0)  bufCount = 0;

                    totalCount += bufCount;

                    break;

                }

                // JVM returned to us with an intentional overflow!

                totalCount += buf.length;

                int excess = bufCount - buf.length;

                if (bufs == null)  bufs = new ArrayList<>(1);

                bufs.add(buf);

                int len2 = buf.length;

                len2 = Math.max(len2, excess);

                len2 = Math.max(len2, totalCount / 4);

                buf = newMemberBuffer(Math.min(BUF_MAX, len2));

            }

            ArrayList<MemberName> result = new ArrayList<>(totalCount);

            if (bufs != null) {

                for (MemberName[] buf0 : bufs) {

                    Collections.addAll(result, buf0);

                }

            }

            result.addAll(Arrays.asList(buf).subList(0, bufCount));

            // Signature matching is not the same as type matching, since

            // one signature might correspond to several types.

            // So if matchType is a Class or MethodType, refilter the results.

            if (matchType != null && matchType != matchSig) {

                for (Iterator<MemberName> it = result.iterator(); it.hasNext();) {

                    MemberName m = it.next();

                    if (!matchType.equals(m.getType()))

                        it.remove();

                }

            }

            return result;

        }

        /** Produce a resolved version of the given member.

         *  Super types are searched (for inherited members) if {@code searchSupers} is true.

         *  Access checking is performed on behalf of the given {@code lookupClass}.

         *  If lookup fails or access is not permitted, null is returned.

         *  Otherwise a fresh copy of the given member is returned, with modifier bits filled in.

         */

        private MemberName resolve(byte refKind, MemberName ref, Class<?> lookupClass) {

            MemberName m = ref.clone();  // JVM will side-effect the ref

            assert(refKind == m.getReferenceKind());

            try {

                m = MethodHandleNatives.resolve(m, lookupClass);

                m.checkForTypeAlias();

                m.resolution = null;

            } catch (LinkageError ex) {

                // JVM reports that the "bytecode behavior" would get an error

                assert(!m.isResolved());

                m.resolution = ex;

                return m;

            }

            assert(m.referenceKindIsConsistent());

            m.initResolved(true);

            assert(m.vminfoIsConsistent());

            return m;

        }

        /** Produce a resolved version of the given member.

         *  Super types are searched (for inherited members) if {@code searchSupers} is true.

         *  Access checking is performed on behalf of the given {@code lookupClass}.

         *  If lookup fails or access is not permitted, a {@linkplain ReflectiveOperationException} is thrown.

         *  Otherwise a fresh copy of the given member is returned, with modifier bits filled in.

         */

        public

        <NoSuchMemberException extends ReflectiveOperationException>

        MemberName resolveOrFail(byte refKind, MemberName m, Class<?> lookupClass,

                                 Class<NoSuchMemberException> nsmClass)

                throws IllegalAccessException, NoSuchMemberException {

            MemberName result = resolve(refKind, m, lookupClass);

            if (result.isResolved())

                return result;

            ReflectiveOperationException ex = result.makeAccessException();