/*

 * Copyright (c) 2008, 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.  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.Member;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Iterator;

import java.util.List;

import java.util.Objects;

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

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

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

/**

 * 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 member has been determined by the JVM.

 * <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 descriptive.

 * 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;

    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.fromDescriptor(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.makeImpl(rtype, ptypes, true);

                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.fromDescriptor("()"+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);

        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 &~ Modifier.PUBLIC;

        final int negs = Modifier.STATIC;

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

            clazz == MethodHandle.class) {

            return isMethodHandleInvokeName(name);

        }

        return false;

    }

    public static boolean isMethodHandleInvokeName(String name) {

        switch (name) {

        case "invoke":

        case "invokeExact":

            return true;

        default:

            return false;

        }

    }

    public boolean isVarHandleMethodInvoke() {

        final int bits = MH_INVOKE_MODS &~ Modifier.PUBLIC;

        final int negs = Modifier.STATIC;

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

            clazz == VarHandle.class) {

            return isVarHandleMethodInvokeName(name);

        }

        return false;

    }

    public static boolean isVarHandleMethodInvokeName(String name) {

        try {

            VarHandle.AccessMode.valueFromMethodName(name);

            return true;

        } catch (IllegalArgumentException e) {

            return false;

        }

    }

    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) {

        int mode = (ALL_ACCESS|MethodHandles.Lookup.PACKAGE|MethodHandles.Lookup.MODULE);

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

                                               lookupClass, mode);