/*

 * 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 sun.reflect.annotation;

import java.lang.annotation.*;

import java.lang.reflect.*;

import java.nio.ByteBuffer;

import java.nio.BufferUnderflowException;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import java.util.LinkedHashMap;

import java.util.Map;

import jdk.internal.misc.SharedSecrets;

import jdk.internal.misc.JavaLangAccess;

import jdk.internal.reflect.ConstantPool;

import static sun.reflect.annotation.TypeAnnotation.*;

/**

 * TypeAnnotationParser implements the logic needed to parse

 * TypeAnnotations from an array of bytes.

 */

public final class TypeAnnotationParser {

    private static final TypeAnnotation[] EMPTY_TYPE_ANNOTATION_ARRAY = new TypeAnnotation[0];

    /**

     * Build an AnnotatedType from the parameters supplied.

     *

     * This method and {@code buildAnnotatedTypes} are probably

     * the entry points you are looking for.

     *

     * @param rawAnnotations the byte[] encoding of all type annotations on this declaration

     * @param cp the ConstantPool needed to parse the embedded Annotation

     * @param decl the declaration this type annotation is on

     * @param container the Class this type annotation is on (may be the same as decl)

     * @param type the type the AnnotatedType corresponds to

     * @param filter the type annotation targets included in this AnnotatedType

     */

    public static AnnotatedType buildAnnotatedType(byte[] rawAnnotations,

            ConstantPool cp,

            AnnotatedElement decl,

            Class<?> container,

            Type type,

            TypeAnnotationTarget filter) {

        TypeAnnotation[] tas = parseTypeAnnotations(rawAnnotations,

                cp, decl, container);

        List<TypeAnnotation> l = new ArrayList<>(tas.length);

        for (TypeAnnotation t : tas) {

            TypeAnnotationTargetInfo ti = t.getTargetInfo();

            if (ti.getTarget() == filter)

                l.add(t);

        }

        TypeAnnotation[] typeAnnotations = l.toArray(EMPTY_TYPE_ANNOTATION_ARRAY);

        return AnnotatedTypeFactory.buildAnnotatedType(type,

                AnnotatedTypeFactory.nestingForType(type, LocationInfo.BASE_LOCATION),

                typeAnnotations,

                typeAnnotations,

                decl);

    }

    /**

     * Build an array of AnnotatedTypes from the parameters supplied.

     *

     * This method and {@code buildAnnotatedType} are probably

     * the entry points you are looking for.

     *

     * @param rawAnnotations the byte[] encoding of all type annotations on this declaration

     * @param cp the ConstantPool needed to parse the embedded Annotation

     * @param decl the declaration this type annotation is on

     * @param container the Class this type annotation is on (may be the same as decl)

     * @param types the Types the AnnotatedTypes corresponds to

     * @param filter the type annotation targets that included in this AnnotatedType

     */

    public static AnnotatedType[] buildAnnotatedTypes(byte[] rawAnnotations,

            ConstantPool cp,

            AnnotatedElement decl,

            Class<?> container,

            Type[] types,

            TypeAnnotationTarget filter) {

        int size = types.length;

        AnnotatedType[] result = new AnnotatedType[size];

        Arrays.fill(result, AnnotatedTypeFactory.EMPTY_ANNOTATED_TYPE);

        @SuppressWarnings("rawtypes")

        ArrayList[] l = new ArrayList[size]; // array of ArrayList<TypeAnnotation>

        TypeAnnotation[] tas = parseTypeAnnotations(rawAnnotations,

                cp, decl, container);

        for (TypeAnnotation t : tas) {

            TypeAnnotationTargetInfo ti = t.getTargetInfo();

            if (ti.getTarget() == filter) {

                int pos = ti.getCount();

                if (l[pos] == null) {

                    ArrayList<TypeAnnotation> tmp = new ArrayList<>(tas.length);

                    l[pos] = tmp;

                }

                @SuppressWarnings("unchecked")

                ArrayList<TypeAnnotation> tmp = l[pos];

                tmp.add(t);

            }

        }

        for (int i = 0; i < size; i++) {

            @SuppressWarnings("unchecked")

            ArrayList<TypeAnnotation> list = l[i];

            TypeAnnotation[] typeAnnotations;

            if (list != null) {

                typeAnnotations = list.toArray(new TypeAnnotation[list.size()]);

            } else {

                typeAnnotations = EMPTY_TYPE_ANNOTATION_ARRAY;

            }

            result[i] = AnnotatedTypeFactory.buildAnnotatedType(types[i],

                    AnnotatedTypeFactory.nestingForType(types[i], LocationInfo.BASE_LOCATION),

                    typeAnnotations,

                    typeAnnotations,

                    decl);

        }

        return result;

    }

    // Class helpers

    /**

     * Build an AnnotatedType for the class decl's supertype.

     *

     * @param rawAnnotations the byte[] encoding of all type annotations on this declaration

     * @param cp the ConstantPool needed to parse the embedded Annotation

     * @param decl the Class which annotated supertype is being built

     */

    public static AnnotatedType buildAnnotatedSuperclass(byte[] rawAnnotations,

            ConstantPool cp,

            Class<?> decl) {

        Type supertype = decl.getGenericSuperclass();

        if (supertype == null)

            return AnnotatedTypeFactory.EMPTY_ANNOTATED_TYPE;

        return buildAnnotatedType(rawAnnotations,

                                  cp,

                                  decl,

                                  decl,

                                  supertype,

                                  TypeAnnotationTarget.CLASS_EXTENDS);

    }

    /**

     * Build an array of AnnotatedTypes for the class decl's implemented

     * interfaces.

     *

     * @param rawAnnotations the byte[] encoding of all type annotations on this declaration

     * @param cp the ConstantPool needed to parse the embedded Annotation

     * @param decl the Class whose annotated implemented interfaces is being built

     */

    public static AnnotatedType[] buildAnnotatedInterfaces(byte[] rawAnnotations,

            ConstantPool cp,

            Class<?> decl) {

        if (decl == Object.class ||

                decl.isArray() ||

                decl.isPrimitive() ||

                decl == Void.TYPE)

            return AnnotatedTypeFactory.EMPTY_ANNOTATED_TYPE_ARRAY;

        return buildAnnotatedTypes(rawAnnotations,

                                   cp,

                                   decl,

                                   decl,

                                   decl.getGenericInterfaces(),

                                   TypeAnnotationTarget.CLASS_IMPLEMENTS);

    }

    // TypeVariable helpers

    /**

     * Parse regular annotations on a TypeVariable declared on genericDecl.

     *

     * Regular Annotations on TypeVariables are stored in the type

     * annotation byte[] in the class file.

     *

     * @param genericDecl the declaration declaring the type variable

     * @param typeVarIndex the 0-based index of this type variable in the declaration

     */

    public static <D extends GenericDeclaration> Annotation[] parseTypeVariableAnnotations(D genericDecl,

            int typeVarIndex) {

        AnnotatedElement decl;

        TypeAnnotationTarget predicate;

        if (genericDecl instanceof Class) {

            decl = (Class<?>)genericDecl;

            predicate = TypeAnnotationTarget.CLASS_TYPE_PARAMETER;

        } else if (genericDecl instanceof Executable) {

            decl = (Executable)genericDecl;

            predicate = TypeAnnotationTarget.METHOD_TYPE_PARAMETER;

        } else {

            throw new AssertionError("Unknown GenericDeclaration " + genericDecl + "\nthis should not happen.");

        }

        List<TypeAnnotation> typeVarAnnos = TypeAnnotation.filter(parseAllTypeAnnotations(decl),

                                                                  predicate);

        List<Annotation> res = new ArrayList<>(typeVarAnnos.size());

        for (TypeAnnotation t : typeVarAnnos)

            if (t.getTargetInfo().getCount() == typeVarIndex)

                res.add(t.getAnnotation());

        return res.toArray(new Annotation[0]);

    }

    /**

     * Build an array of AnnotatedTypes for the declaration decl's bounds.

     *

     * @param bounds the bounds corresponding to the annotated bounds

     * @param decl the declaration whose annotated bounds is being built

     * @param typeVarIndex the index of this type variable on the decl

     */

    public static <D extends GenericDeclaration> AnnotatedType[] parseAnnotatedBounds(Type[] bounds,

            D decl,

            int typeVarIndex) {

        return parseAnnotatedBounds(bounds, decl, typeVarIndex, LocationInfo.BASE_LOCATION);

    }

    //helper for above

    private static <D extends GenericDeclaration> AnnotatedType[] parseAnnotatedBounds(Type[] bounds,

            D decl,

            int typeVarIndex,

            LocationInfo loc) {

        List<TypeAnnotation> candidates = fetchBounds(decl);

        if (bounds != null) {

            int startIndex = 0;

            AnnotatedType[] res = new AnnotatedType[bounds.length];

            // Adjust bounds index

            //

            // Figure out if the type annotations for this bound starts with 0

            // or 1. The spec says within a bound the 0:th type annotation will

            // always be on an bound of a Class type (not Interface type). So

            // if the programmer starts with an Interface type for the first

            // (and following) bound(s) the implicit Object bound is considered

            // the first (that is 0:th) bound and type annotations start on

            // index 1.

            if (bounds.length > 0) {

                Type b0 = bounds[0];

                if (!(b0 instanceof Class<?>)) {

                    startIndex = 1;

                } else {

                    Class<?> c = (Class<?>)b0;

                    if (c.isInterface()) {

                        startIndex = 1;

                    }

                }

            }

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

                List<TypeAnnotation> l = new ArrayList<>(candidates.size());

                for (TypeAnnotation t : candidates) {

                    TypeAnnotationTargetInfo tInfo = t.getTargetInfo();

                    if (tInfo.getSecondaryIndex() == i + startIndex &&

                            tInfo.getCount() == typeVarIndex) {

                        l.add(t);

                    }

                }

                res[i] = AnnotatedTypeFactory.buildAnnotatedType(bounds[i],

                        AnnotatedTypeFactory.nestingForType(bounds[i], loc),

                        l.toArray(EMPTY_TYPE_ANNOTATION_ARRAY),

                        candidates.toArray(EMPTY_TYPE_ANNOTATION_ARRAY),

                        (AnnotatedElement)decl);

            }

            return res;

        }

        return new AnnotatedType[0];

    }

    private static <D extends GenericDeclaration> List<TypeAnnotation> fetchBounds(D decl) {

        AnnotatedElement boundsDecl;

        TypeAnnotationTarget target;

        if (decl instanceof Class) {

            target = TypeAnnotationTarget.CLASS_TYPE_PARAMETER_BOUND;

            boundsDecl = (Class)decl;

        } else {

            target = TypeAnnotationTarget.METHOD_TYPE_PARAMETER_BOUND;

            boundsDecl = (Executable)decl;

        }

        return TypeAnnotation.filter(TypeAnnotationParser.parseAllTypeAnnotations(boundsDecl), target);

    }

    /*

     * Parse all type annotations on the declaration supplied. This is needed

     * when you go from for example an annotated return type on a method that

     * is a type variable declared on the class. In this case you need to

     * 'jump' to the decl of the class and parse all type annotations there to

     * find the ones that are applicable to the type variable.

     */

    static TypeAnnotation[] parseAllTypeAnnotations(AnnotatedElement decl) {

        Class<?> container;

        byte[] rawBytes;

        JavaLangAccess javaLangAccess = SharedSecrets.getJavaLangAccess();

        if (decl instanceof Class) {

            container = (Class<?>)decl;

            rawBytes = javaLangAccess.getRawClassTypeAnnotations(container);

        } else if (decl instanceof Executable) {

            container = ((Executable)decl).getDeclaringClass();

            rawBytes = javaLangAccess.getRawExecutableTypeAnnotations((Executable)decl);

        } else {

            // Should not reach here. Assert?

            return EMPTY_TYPE_ANNOTATION_ARRAY;

        }

        return parseTypeAnnotations(rawBytes, javaLangAccess.getConstantPool(container),

                                    decl, container);

    }

    /* Parse type annotations encoded as an array of bytes */

    private static TypeAnnotation[] parseTypeAnnotations(byte[] rawAnnotations,

            ConstantPool cp,

            AnnotatedElement baseDecl,

            Class<?> container) {

        if (rawAnnotations == null)

            return EMPTY_TYPE_ANNOTATION_ARRAY;

        ByteBuffer buf = ByteBuffer.wrap(rawAnnotations);

        int annotationCount = buf.getShort() & 0xFFFF;

        List<TypeAnnotation> typeAnnotations = new ArrayList<>(annotationCount);

        // Parse each TypeAnnotation

        for (int i = 0; i < annotationCount; i++) {

             TypeAnnotation ta = parseTypeAnnotation(buf, cp, baseDecl, container);

             if (ta != null)

                 typeAnnotations.add(ta);

        }

        return typeAnnotations.toArray(EMPTY_TYPE_ANNOTATION_ARRAY);

    }

    // Helper

    static Map<Class<? extends Annotation>, Annotation> mapTypeAnnotations(TypeAnnotation[] typeAnnos) {

        Map<Class<? extends Annotation>, Annotation> result =

            new LinkedHashMap<>();

        for (TypeAnnotation t : typeAnnos) {

            Annotation a = t.getAnnotation();

                    throw new AnnotationFormatError("Duplicate annotation for class: "+klass+": " + a);

        }

        return result;

    }

    // Position codes

    // Regular type parameter annotations

    private static final byte CLASS_TYPE_PARAMETER = 0x00;

    private static final byte METHOD_TYPE_PARAMETER = 0x01;

    // Type Annotations outside method bodies

    private static final byte CLASS_EXTENDS = 0x10;

    private static final byte CLASS_TYPE_PARAMETER_BOUND = 0x11;

    private static final byte METHOD_TYPE_PARAMETER_BOUND = 0x12;

    private static final byte FIELD = 0x13;

    private static final byte METHOD_RETURN = 0x14;

    private static final byte METHOD_RECEIVER = 0x15;

    private static final byte METHOD_FORMAL_PARAMETER = 0x16;

    private static final byte THROWS = 0x17;

    // Type Annotations inside method bodies

    private static final byte LOCAL_VARIABLE = (byte)0x40;

    private static final byte RESOURCE_VARIABLE = (byte)0x41;

    private static final byte EXCEPTION_PARAMETER = (byte)0x42;

    private static final byte INSTANCEOF = (byte)0x43;

    private static final byte NEW = (byte)0x44;

    private static final byte CONSTRUCTOR_REFERENCE = (byte)0x45;

    private static final byte METHOD_REFERENCE = (byte)0x46;

    private static final byte CAST = (byte)0x47;

    private static final byte CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT = (byte)0x48;

    private static final byte METHOD_INVOCATION_TYPE_ARGUMENT = (byte)0x49;

    private static final byte CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT = (byte)0x4A;

    private static final byte METHOD_REFERENCE_TYPE_ARGUMENT = (byte)0x4B;

    private static TypeAnnotation parseTypeAnnotation(ByteBuffer buf,

            ConstantPool cp,

            AnnotatedElement baseDecl,

            Class<?> container) {

        try {

            TypeAnnotationTargetInfo ti = parseTargetInfo(buf);

            LocationInfo locationInfo = LocationInfo.parseLocationInfo(buf);

            Annotation a = AnnotationParser.parseAnnotation(buf, cp, container, false);

            if (ti == null) // Inside a method for example

                return null;

            return new TypeAnnotation(ti, locationInfo, a, baseDecl);

        } catch (IllegalArgumentException | // Bad type in const pool at specified index

                BufferUnderflowException e) {

            throw new AnnotationFormatError(e);

        }

    }

    private static TypeAnnotationTargetInfo parseTargetInfo(ByteBuffer buf) {

        int posCode = buf.get() & 0xFF;

        switch(posCode) {

        case CLASS_TYPE_PARAMETER:

        case METHOD_TYPE_PARAMETER: {

            int index = buf.get() & 0xFF;

            TypeAnnotationTargetInfo res;

            if (posCode == CLASS_TYPE_PARAMETER)

                res = new TypeAnnotationTargetInfo(TypeAnnotationTarget.CLASS_TYPE_PARAMETER,

                        index);

            else

                res = new TypeAnnotationTargetInfo(TypeAnnotationTarget.METHOD_TYPE_PARAMETER,

                        index);

            return res;

            } // unreachable break;

        case CLASS_EXTENDS: {

            short index = buf.getShort(); //needs to be signed

            if (index == -1) {

                return new TypeAnnotationTargetInfo(TypeAnnotationTarget.CLASS_EXTENDS);

            } else if (index >= 0) {

                TypeAnnotationTargetInfo res = new TypeAnnotationTargetInfo(TypeAnnotationTarget.CLASS_IMPLEMENTS,

                        index);

                return res;

            }} break;

        case CLASS_TYPE_PARAMETER_BOUND:

            return parse2ByteTarget(TypeAnnotationTarget.CLASS_TYPE_PARAMETER_BOUND, buf);

        case METHOD_TYPE_PARAMETER_BOUND:

            return parse2ByteTarget(TypeAnnotationTarget.METHOD_TYPE_PARAMETER_BOUND, buf);

        case FIELD:

            return new TypeAnnotationTargetInfo(TypeAnnotationTarget.FIELD);

        case METHOD_RETURN:

            return new TypeAnnotationTargetInfo(TypeAnnotationTarget.METHOD_RETURN);

        case METHOD_RECEIVER:

            return new TypeAnnotationTargetInfo(TypeAnnotationTarget.METHOD_RECEIVER);

        case METHOD_FORMAL_PARAMETER: {

            int index = buf.get() & 0xFF;

            return new TypeAnnotationTargetInfo(TypeAnnotationTarget.METHOD_FORMAL_PARAMETER,

                    index);

            } //unreachable break;

        case THROWS:

            return parseShortTarget(TypeAnnotationTarget.THROWS, buf);

        /*

         * The ones below are inside method bodies, we don't care about them for core reflection

         * other than adjusting for them in the byte stream.

         */

        case LOCAL_VARIABLE:

        case RESOURCE_VARIABLE:

            short length = buf.getShort();

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

                short offset = buf.getShort();

                short varLength = buf.getShort();

                short index = buf.getShort();

            }

            return null;

        case EXCEPTION_PARAMETER: {

            byte index = buf.get();

            }

            return null;

        case INSTANCEOF:

        case NEW:

        case CONSTRUCTOR_REFERENCE:

        case METHOD_REFERENCE: {

            short offset = buf.getShort();

            }

            return null;

        case CAST:

        case CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT:

        case METHOD_INVOCATION_TYPE_ARGUMENT:

        case CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT:

        case METHOD_REFERENCE_TYPE_ARGUMENT: {

            short offset = buf.getShort();

            byte index = buf.get();

            }

            return null;

        default:

            // will throw error below

            break;

        }

        throw new AnnotationFormatError("Could not parse bytes for type annotations");

    }

    private static TypeAnnotationTargetInfo parseShortTarget(TypeAnnotationTarget target, ByteBuffer buf) {

        int index = buf.getShort() & 0xFFFF;

        return new TypeAnnotationTargetInfo(target, index);

    }

    private static TypeAnnotationTargetInfo parse2ByteTarget(TypeAnnotationTarget target, ByteBuffer buf) {

        int count = buf.get() & 0xFF;

        int secondaryIndex = buf.get() & 0xFF;

        return new TypeAnnotationTargetInfo(target,

                                            count,

                                            secondaryIndex);

    }

}