/*

 * Copyright (c) 2012, 2019, 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.reflect;

import java.lang.annotation.*;

import java.util.Arrays;

import java.util.Map;

import java.util.Objects;

import java.util.StringJoiner;

import java.util.stream.Stream;

import java.util.stream.Collectors;

import jdk.internal.access.SharedSecrets;

import sun.reflect.annotation.AnnotationParser;

import sun.reflect.annotation.AnnotationSupport;

import sun.reflect.annotation.TypeAnnotationParser;

import sun.reflect.annotation.TypeAnnotation;

import sun.reflect.generics.repository.ConstructorRepository;

/**

 * A shared superclass for the common functionality of {@link Method}

 * and {@link Constructor}.

 *

 * @since 1.8

 */

public abstract class Executable extends AccessibleObject

    implements Member, GenericDeclaration {

    /*

     * Only grant package-visibility to the constructor.

     */

    Executable() {}

    /**

     * Accessor method to allow code sharing

     */

    abstract byte[] getAnnotationBytes();

    /**

     * Does the Executable have generic information.

     */

    abstract boolean hasGenericInformation();

    abstract ConstructorRepository getGenericInfo();

    boolean equalParamTypes(Class<?>[] params1, Class<?>[] params2) {

        /* Avoid unnecessary cloning */

        if (params1.length == params2.length) {

            for (int i = 0; i < params1.length; i++) {

                if (params1[i] != params2[i])

                    return false;

            }

            return true;

        }

        return false;

    }

    Annotation[][] parseParameterAnnotations(byte[] parameterAnnotations) {

        return AnnotationParser.parseParameterAnnotations(

               parameterAnnotations,

               SharedSecrets.getJavaLangAccess().

               getConstantPool(getDeclaringClass()),

               getDeclaringClass());

    }

    void printModifiersIfNonzero(StringBuilder sb, int mask, boolean isDefault) {

        int mod = getModifiers() & mask;

        if (mod != 0 && !isDefault) {

            sb.append(Modifier.toString(mod)).append(' ');

        } else {

            int access_mod = mod & Modifier.ACCESS_MODIFIERS;

            if (access_mod != 0)

                sb.append(Modifier.toString(access_mod)).append(' ');

            if (isDefault)

                sb.append("default ");

            mod = (mod & ~Modifier.ACCESS_MODIFIERS);

            if (mod != 0)

                sb.append(Modifier.toString(mod)).append(' ');

        }

    }

    String sharedToString(int modifierMask,

                          boolean isDefault,

                          Class<?>[] parameterTypes,

                          Class<?>[] exceptionTypes) {

        try {

            StringBuilder sb = new StringBuilder();

            printModifiersIfNonzero(sb, modifierMask, isDefault);

            specificToStringHeader(sb);

            sb.append(Arrays.stream(parameterTypes)

                      .map(Type::getTypeName)

                      .collect(Collectors.joining(",", "(", ")")));

            if (exceptionTypes.length > 0) {

                sb.append(Arrays.stream(exceptionTypes)

                          .map(Type::getTypeName)

                          .collect(Collectors.joining(",", " throws ", "")));

            }

            return sb.toString();

        } catch (Exception e) {

            return "<" + e + ">";

        }

    }

    /**

     * Generate toString header information specific to a method or

     * constructor.

     */

    abstract void specificToStringHeader(StringBuilder sb);

    static String typeVarBounds(TypeVariable<?> typeVar) {

        Type[] bounds = typeVar.getBounds();

        if (bounds.length == 1 && bounds[0].equals(Object.class)) {

            return typeVar.getName();

        } else {

            return typeVar.getName() + " extends " +

                Arrays.stream(bounds)

                .map(Type::getTypeName)

                .collect(Collectors.joining(" & "));

        }

    }

    String sharedToGenericString(int modifierMask, boolean isDefault) {

        try {

            StringBuilder sb = new StringBuilder();

            printModifiersIfNonzero(sb, modifierMask, isDefault);

            TypeVariable<?>[] typeparms = getTypeParameters();

            if (typeparms.length > 0) {

                sb.append(Arrays.stream(typeparms)

                          .map(Executable::typeVarBounds)

                          .collect(Collectors.joining(",", "<", "> ")));

            }

            specificToGenericStringHeader(sb);

            sb.append('(');

            StringJoiner sj = new StringJoiner(",");

            Type[] params = getGenericParameterTypes();

            for (int j = 0; j < params.length; j++) {

                String param = params[j].getTypeName();

                if (isVarArgs() && (j == params.length - 1)) // replace T[] with T...

                    param = param.replaceFirst("\\[\\]$", "...");

                sj.add(param);

            }

            sb.append(sj.toString());

            sb.append(')');

            Type[] exceptionTypes = getGenericExceptionTypes();

            if (exceptionTypes.length > 0) {

                sb.append(Arrays.stream(exceptionTypes)

                          .map(Type::getTypeName)

                          .collect(Collectors.joining(",", " throws ", "")));

            }

            return sb.toString();

        } catch (Exception e) {

            return "<" + e + ">";

        }

    }

    /**

     * Generate toGenericString header information specific to a

     * method or constructor.

     */

    abstract void specificToGenericStringHeader(StringBuilder sb);

    /**

     * Returns the {@code Class} object representing the class or interface

     * that declares the executable represented by this object.

     */

    public abstract Class<?> getDeclaringClass();

    /**

     * Returns the name of the executable represented by this object.

     */

    public abstract String getName();

    /**

     * Returns the Java language {@linkplain Modifier modifiers} for

     * the executable represented by this object.

     */

    public abstract int getModifiers();

    /**

     * Returns an array of {@code TypeVariable} objects that represent the

     * type variables declared by the generic declaration represented by this

     * {@code GenericDeclaration} object, in declaration order.  Returns an

     * array of length 0 if the underlying generic declaration declares no type

     * variables.

     *

     * @return an array of {@code TypeVariable} objects that represent

     *     the type variables declared by this generic declaration

     * @throws GenericSignatureFormatError if the generic

     *     signature of this generic declaration does not conform to

     *     the format specified in

     *     <cite>The Java&trade; Virtual Machine Specification</cite>

     */

    public abstract TypeVariable<?>[] getTypeParameters();

    // returns shared array of parameter types - must never give it out

    // to the untrusted code...

    abstract Class<?>[] getSharedParameterTypes();

    // returns shared array of exception types - must never give it out

    // to the untrusted code...

    abstract Class<?>[] getSharedExceptionTypes();

    /**

     * Returns an array of {@code Class} objects that represent the formal

     * parameter types, in declaration order, of the executable

     * represented by this object.  Returns an array of length

     * 0 if the underlying executable takes no parameters.

     * Note that the constructors of some inner classes

     * may have an implicitly declared parameter in addition to

     * explicitly declared ones.

     *

     * @return the parameter types for the executable this object

     * represents

     */

    public abstract Class<?>[] getParameterTypes();

    /**

     * Returns the number of formal parameters (whether explicitly

     * declared or implicitly declared or neither) for the executable

     * represented by this object.

     *

     * @return The number of formal parameters for the executable this

     * object represents

     */

    public int getParameterCount() {

        throw new AbstractMethodError();

    }

    /**

     * Returns an array of {@code Type} objects that represent the formal

     * parameter types, in declaration order, of the executable represented by

     * this object. Returns an array of length 0 if the

     * underlying executable takes no parameters.

     * Note that the constructors of some inner classes

     * may have an implicitly declared parameter in addition to

     * explicitly declared ones.

     *

     * <p>If a formal parameter type is a parameterized type,

     * the {@code Type} object returned for it must accurately reflect

     * the actual type arguments used in the source code.

     *

     * <p>If a formal parameter type is a type variable or a parameterized

     * type, it is created. Otherwise, it is resolved.

     *

     * @return an array of {@code Type}s that represent the formal

     *     parameter types of the underlying executable, in declaration order

     * @throws GenericSignatureFormatError

     *     if the generic method signature does not conform to the format

     *     specified in

     *     <cite>The Java&trade; Virtual Machine Specification</cite>

     * @throws TypeNotPresentException if any of the parameter

     *     types of the underlying executable refers to a non-existent type

     *     declaration

     * @throws MalformedParameterizedTypeException if any of

     *     the underlying executable's parameter types refer to a parameterized

     *     type that cannot be instantiated for any reason

     */

    public Type[] getGenericParameterTypes() {

        if (hasGenericInformation())

            return getGenericInfo().getParameterTypes();

        else

            return getParameterTypes();

    }

    /**

     * Behaves like {@code getGenericParameterTypes}, but returns type

     * information for all parameters, including synthetic parameters.

     */

    Type[] getAllGenericParameterTypes() {

        final boolean genericInfo = hasGenericInformation();

        // Easy case: we don't have generic parameter information.  In

        // this case, we just return the result of

        // getParameterTypes().

        if (!genericInfo) {

            return getParameterTypes();

        } else {

            final boolean realParamData = hasRealParameterData();

            final Type[] genericParamTypes = getGenericParameterTypes();

            final Type[] nonGenericParamTypes = getParameterTypes();

            final Type[] out = new Type[nonGenericParamTypes.length];

            final Parameter[] params = getParameters();

            int fromidx = 0;

            // If we have real parameter data, then we use the

            // synthetic and mandate flags to our advantage.

            if (realParamData) {

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

                    final Parameter param = params[i];

                    if (param.isSynthetic() || param.isImplicit()) {

                        // If we hit a synthetic or mandated parameter,

                        // use the non generic parameter info.

                        out[i] = nonGenericParamTypes[i];

                    } else {

                        // Otherwise, use the generic parameter info.

                        out[i] = genericParamTypes[fromidx];

                        fromidx++;

                    }

                }

            } else {

                // Otherwise, use the non-generic parameter data.

                // Without method parameter reflection data, we have

                // no way to figure out which parameters are

                // synthetic/mandated, thus, no way to match up the

                // indexes.

                return genericParamTypes.length == nonGenericParamTypes.length ?

                    genericParamTypes : nonGenericParamTypes;

            }

            return out;

        }

    }

    /**

     * Returns an array of {@code Parameter} objects that represent

     * all the parameters to the underlying executable represented by

     * this object.  Returns an array of length 0 if the executable

     * has no parameters.

     *

     * <p>The parameters of the underlying executable do not necessarily

     * have unique names, or names that are legal identifiers in the

     * Java programming language (JLS 3.8).

     *

     * @throws MalformedParametersException if the class file contains

     * a MethodParameters attribute that is improperly formatted.

     * @return an array of {@code Parameter} objects representing all

     * the parameters to the executable this object represents.

     */

    public Parameter[] getParameters() {

        // TODO: This may eventually need to be guarded by security

        // mechanisms similar to those in Field, Method, etc.

        //

        // Need to copy the cached array to prevent users from messing

        // with it.  Since parameters are immutable, we can

        // shallow-copy.

        return privateGetParameters().clone();

    }

    private Parameter[] synthesizeAllParams() {

        final int realparams = getParameterCount();

        final Parameter[] out = new Parameter[realparams];

        for (int i = 0; i < realparams; i++)

            // TODO: is there a way to synthetically derive the

            // modifiers?  Probably not in the general case, since

            // we'd have no way of knowing about them, but there

            // may be specific cases.

            out[i] = new Parameter("arg" + i, 0, this, i);

        return out;

    }

    private void verifyParameters(final Parameter[] parameters) {

        final int mask = Modifier.FINAL | Modifier.SYNTHETIC | Modifier.MANDATED;

        if (getParameterTypes().length != parameters.length)

            throw new MalformedParametersException("Wrong number of parameters in MethodParameters attribute");

        for (Parameter parameter : parameters) {

            final String name = parameter.getRealName();

            final int mods = parameter.getModifiers();

            if (name != null) {

                if (name.isEmpty() || name.indexOf('.') != -1 ||

                    name.indexOf(';') != -1 || name.indexOf('[') != -1 ||

                    name.indexOf('/') != -1) {

                    throw new MalformedParametersException("Invalid parameter name \"" + name + "\"");

                }

            }

            if (mods != (mods & mask)) {

                throw new MalformedParametersException("Invalid parameter modifiers");

            }

        }

    }

    private Parameter[] privateGetParameters() {

        // Use tmp to avoid multiple writes to a volatile.

        Parameter[] tmp = parameters;

        if (tmp == null) {

            // Otherwise, go to the JVM to get them

            try {

                tmp = getParameters0();

            } catch(IllegalArgumentException e) {

                // Rethrow ClassFormatErrors

                throw new MalformedParametersException("Invalid constant pool index");

            }

            // If we get back nothing, then synthesize parameters

            if (tmp == null) {

                hasRealParameterData = false;

                tmp = synthesizeAllParams();

            } else {

                hasRealParameterData = true;

                verifyParameters(tmp);

            }

            parameters = tmp;

        }

        return tmp;

    }

    boolean hasRealParameterData() {

        // If this somehow gets called before parameters gets

        // initialized, force it into existence.

        if (parameters == null) {

            privateGetParameters();

        }

        return hasRealParameterData;

    }

    private transient volatile boolean hasRealParameterData;

    private transient volatile Parameter[] parameters;

    private native Parameter[] getParameters0();

    native byte[] getTypeAnnotationBytes0();

    // Needed by reflectaccess

    byte[] getTypeAnnotationBytes() {

        return getTypeAnnotationBytes0();

    }

    /**

     * Returns an array of {@code Class} objects that represent the

     * types of exceptions declared to be thrown by the underlying

     * executable represented by this object.  Returns an array of

     * length 0 if the executable declares no exceptions in its {@code

     * throws} clause.

     *

     * @return the exception types declared as being thrown by the

     * executable this object represents

     */

    public abstract Class<?>[] getExceptionTypes();

    /**

     * Returns an array of {@code Type} objects that represent the

     * exceptions declared to be thrown by this executable object.

     * Returns an array of length 0 if the underlying executable declares

     * no exceptions in its {@code throws} clause.

     *

     * <p>If an exception type is a type variable or a parameterized

     * type, it is created. Otherwise, it is resolved.

     *

     * @return an array of Types that represent the exception types

     *     thrown by the underlying executable

     * @throws GenericSignatureFormatError

     *     if the generic method signature does not conform to the format

     *     specified in

     *     <cite>The Java&trade; Virtual Machine Specification</cite>

     * @throws TypeNotPresentException if the underlying executable's

     *     {@code throws} clause refers to a non-existent type declaration

     * @throws MalformedParameterizedTypeException if

     *     the underlying executable's {@code throws} clause refers to a

     *     parameterized type that cannot be instantiated for any reason

     */

    public Type[] getGenericExceptionTypes() {

        Type[] result;

        if (hasGenericInformation() &&

            ((result = getGenericInfo().getExceptionTypes()).length > 0))

            return result;

        else

            return getExceptionTypes();

    }

    /**

     * Returns a string describing this {@code Executable}, including

     * any type parameters.

     * @return a string describing this {@code Executable}, including

     * any type parameters

     */

    public abstract String toGenericString();

    /**

     * Returns {@code true} if this executable was declared to take a

     * variable number of arguments; returns {@code false} otherwise.

     *