/*

 * Copyright (c) 2008, 2011, 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.

 */

import sun.dyn.util.BytecodeDescriptor;

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;

/**

 * 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

 */

    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

    private Object     vmtarget;    // VM-specific target value

    private int        vmindex;     // method index within class or interface

    { vmindex = VM_INDEX_UNINITIALIZED; }

    /** 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() {

        if (clazz == null && isResolved()) {

            expandFromVM();

        }

        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;

    }

    /** 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");

        if (type instanceof MethodType) {

            return (MethodType) type;

        }

        if (type instanceof String) {

            String sig = (String) type;

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

            this.type = res;

            return res;

        }

        if (type instanceof Object[]) {

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

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

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

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

            this.type = res;

            return res;

        }

        throw new InternalError("bad method type "+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 = getMethodType();

        if (!isStatic())

            itype = 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");

        if (type instanceof Class<?>) {

            return (Class<?>) type;

        }

        if (type instanceof String) {

            String sig = (String) type;

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

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

            this.type = res;

            return res;

        }

        throw new InternalError("bad field type "+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 (type instanceof String)

            return (String) type;

        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);

    }

    private void setFlags(int flags) {

        this.flags = flags;

        assert(testAnyFlags(ALL_KINDS));

    }

    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 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 the modifier flags of this member. */

    public boolean isAbstract() {

        return Modifier.isAbstract(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

    static final int  // for MethodHandleNatives.getMembers

            SEARCH_SUPERCLASSES = MN_SEARCH_SUPERCLASSES,

            SEARCH_INTERFACES   = MN_SEARCH_INTERFACES;

    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 = SEARCH_SUPERCLASSES | 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);

    }

    /** 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;

        setFlags(flags);

        assert(!isResolved());

    }

    private void expandFromVM() {

        if (!isResolved())  return;

        if (type instanceof Object[])

            type = null;  // don't saddle JVM w/ typeInfo

        MethodHandleNatives.expand(this);

    }

    // Capturing information from the Core Reflection API:

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

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

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

        return flags | mods;

    }

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

    public MemberName(Method m) {

        Object[] typeInfo = { m.getReturnType(), m.getParameterTypes() };

        init(m.getDeclaringClass(), m.getName(), typeInfo, flagsMods(IS_METHOD, m.getModifiers()));

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

        MethodHandleNatives.init(this, m);

        assert(isResolved());

    }

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

    public MemberName(Constructor ctor) {

        Object[] typeInfo = { void.class, ctor.getParameterTypes() };

        init(ctor.getDeclaringClass(), CONSTRUCTOR_NAME, typeInfo, flagsMods(IS_CONSTRUCTOR, ctor.getModifiers()));

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

        MethodHandleNatives.init(this, ctor);

        assert(isResolved());

    }

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

    public MemberName(Field fld) {

        init(fld.getDeclaringClass(), fld.getName(), fld.getType(), flagsMods(IS_FIELD, fld.getModifiers()));

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

        MethodHandleNatives.init(this, fld);

        assert(isResolved());

    }

    /** 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()));

        vmindex = 0;  // isResolved

        assert(isResolved());

    }

    // 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 new InternalError();

        }

     }

    // %%% define equals/hashcode?

    // Construction from symbolic parts, for queries:

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

     *  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, int modifiers) {

        init(defClass, name, type, IS_FIELD | (modifiers & RECOGNIZED_MODIFIERS));

    }

    /** 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) {

        this(defClass, name, type, 0);

    }

    /** 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 resulting name will in an unresolved state.

     */

    public MemberName(Class<?> defClass, String name, MethodType type, int modifiers) {

        int flagBit = (name.equals(CONSTRUCTOR_NAME) ? IS_CONSTRUCTOR : IS_METHOD);

        init(defClass, name, type, flagBit | (modifiers & RECOGNIZED_MODIFIERS));

    }

    /** 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 modifier flags default to zero.

     *  The resulting name will in an unresolved state.

     */

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

        this(defClass, name, type, 0);

    }

    /** 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 (vmindex != VM_INDEX_UNINITIALIZED);

    }

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

     */

    public boolean hasReceiverTypeDispatch() {

    }

    /** 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.

     */

    @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));

        }

        /*

        buf.append('/');

        // key: Public, private, pRotected, sTatic, Final, sYnchronized,

        // transient/Varargs, native, (interface), abstract, sTrict, sYnthetic,

        // (annotation), Enum, (unused)

        final String FIELD_MOD_CHARS  = "PprTF?vt????Y?E?";

        final String METHOD_MOD_CHARS = "PprTFybVn?atY???";

        String modChars = (isInvocable() ? METHOD_MOD_CHARS : FIELD_MOD_CHARS);

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

            if ((flags & (1 << i)) != 0) {

                char mc = modChars.charAt(i);

                if (mc != '?')

                    buf.append(mc);

            }

        }

         */

        return buf.toString();

    }

    private static String getName(Object obj) {

        if (obj instanceof Class<?>)

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

        return String.valueOf(obj);

    }

    // Queries to the JVM:

    /** Document? */

        if (!isResolved())

        return vmindex;

    }

//        if (!isResolved())

//        return vmtarget;

//    }

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

        return new IllegalAccessException(message);

    }