/*

 * Copyright (c) 2009, 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 com.sun.tools.javac.code;

import javax.lang.model.element.Element;

import javax.lang.model.element.ElementKind;

import javax.lang.model.type.TypeKind;

import javax.tools.JavaFileObject;

import com.sun.tools.javac.code.Attribute.TypeCompound;

import com.sun.tools.javac.code.Type.ArrayType;

import com.sun.tools.javac.code.Type.CapturedType;

import com.sun.tools.javac.code.Type.ClassType;

import com.sun.tools.javac.code.Type.ErrorType;

import com.sun.tools.javac.code.Type.ForAll;

import com.sun.tools.javac.code.Type.MethodType;

import com.sun.tools.javac.code.Type.PackageType;

import com.sun.tools.javac.code.Type.TypeVar;

import com.sun.tools.javac.code.Type.UndetVar;

import com.sun.tools.javac.code.Type.Visitor;

import com.sun.tools.javac.code.Type.WildcardType;

import com.sun.tools.javac.code.TypeAnnotationPosition.TypePathEntry;

import com.sun.tools.javac.code.TypeAnnotationPosition.TypePathEntryKind;

import com.sun.tools.javac.code.Symbol.VarSymbol;

import com.sun.tools.javac.code.Symbol.MethodSymbol;

import com.sun.tools.javac.comp.Annotate;

import com.sun.tools.javac.comp.Annotate.Worker;

import com.sun.tools.javac.comp.Attr;

import com.sun.tools.javac.comp.AttrContext;

import com.sun.tools.javac.comp.Env;

import com.sun.tools.javac.tree.JCTree;

import com.sun.tools.javac.tree.TreeInfo;

import com.sun.tools.javac.tree.JCTree.JCBlock;

import com.sun.tools.javac.tree.JCTree.JCClassDecl;

import com.sun.tools.javac.tree.JCTree.JCExpression;

import com.sun.tools.javac.tree.JCTree.JCLambda;

import com.sun.tools.javac.tree.JCTree.JCMethodDecl;

import com.sun.tools.javac.tree.JCTree.JCMethodInvocation;

import com.sun.tools.javac.tree.JCTree.JCNewClass;

import com.sun.tools.javac.tree.JCTree.JCTypeApply;

import com.sun.tools.javac.tree.JCTree.JCVariableDecl;

import com.sun.tools.javac.tree.TreeScanner;

import com.sun.tools.javac.tree.JCTree.*;

import com.sun.tools.javac.util.Assert;

import com.sun.tools.javac.util.Context;

import com.sun.tools.javac.util.List;

import com.sun.tools.javac.util.ListBuffer;

import com.sun.tools.javac.util.Log;

import com.sun.tools.javac.util.Names;

import com.sun.tools.javac.util.Options;

/**

 * Contains operations specific to processing type annotations.

 * This class has two functions:

 * separate declaration from type annotations and insert the type

 * annotations to their types;

 * and determine the TypeAnnotationPositions for all type annotations.

 */

public class TypeAnnotations {

    protected static final Context.Key<TypeAnnotations> typeAnnosKey = new Context.Key<>();

    public static TypeAnnotations instance(Context context) {

        TypeAnnotations instance = context.get(typeAnnosKey);

        if (instance == null)

            instance = new TypeAnnotations(context);

        return instance;

    }

    final Log log;

    final Names names;

    final Symtab syms;

    final Annotate annotate;

    final Attr attr;

    protected TypeAnnotations(Context context) {

        context.put(typeAnnosKey, this);

        names = Names.instance(context);

        log = Log.instance(context);

        syms = Symtab.instance(context);

        annotate = Annotate.instance(context);

        attr = Attr.instance(context);

        Options options = Options.instance(context);

    }

    /**

     * Separate type annotations from declaration annotations and

     * determine the correct positions for type annotations.

     * This version only visits types in signatures and should be

     * called from MemberEnter.

     * The method takes the Annotate object as parameter and

     * adds an Annotate.Worker to the correct Annotate queue for

     * later processing.

     */

    public void organizeTypeAnnotationsSignatures(final Env<AttrContext> env, final JCClassDecl tree) {

        annotate.afterRepeated( new Worker() {

            @Override

            public void run() {

                JavaFileObject oldSource = log.useSource(env.toplevel.sourcefile);

                try {

                    new TypeAnnotationPositions(true).scan(tree);

                } finally {

                    log.useSource(oldSource);

                }

            }

        } );

    }

    public void validateTypeAnnotationsSignatures(final Env<AttrContext> env, final JCClassDecl tree) {

        annotate.validate(new Worker() { //validate annotations

            @Override

            public void run() {

                JavaFileObject oldSource = log.useSource(env.toplevel.sourcefile);

                try {

                    attr.validateTypeAnnotations(tree, true);

                } finally {

                    log.useSource(oldSource);

                }

            }

        } );

    }

    /**

     * This version only visits types in bodies, that is, field initializers,

     * top-level blocks, and method bodies, and should be called from Attr.

     */

    public void organizeTypeAnnotationsBodies(JCClassDecl tree) {

        new TypeAnnotationPositions(false).scan(tree);

    }

    public enum AnnotationType { DECLARATION, TYPE, BOTH }

    /**

     * Determine whether an annotation is a declaration annotation,

     * a type annotation, or both.

     */

    public AnnotationType annotationType(Attribute.Compound a, Symbol s) {

        Attribute.Compound atTarget =

            a.type.tsym.attribute(syms.annotationTargetType.tsym);

        if (atTarget == null) {

            return inferTargetMetaInfo(a, s);

        }

        Attribute atValue = atTarget.member(names.value);

        if (!(atValue instanceof Attribute.Array)) {

            Assert.error("annotationType(): bad @Target argument " + atValue +

                    " (" + atValue.getClass() + ")");

            return AnnotationType.DECLARATION; // error recovery

        }

        Attribute.Array arr = (Attribute.Array) atValue;

        boolean isDecl = false, isType = false;

        for (Attribute app : arr.values) {

            if (!(app instanceof Attribute.Enum)) {

                Assert.error("annotationType(): unrecognized Attribute kind " + app +

                        " (" + app.getClass() + ")");

                isDecl = true;

                continue;

            }

            Attribute.Enum e = (Attribute.Enum) app;

            if (e.value.name == names.TYPE) {

                if (s.kind == Kinds.TYP)

                    isDecl = true;

            } else if (e.value.name == names.FIELD) {

                if (s.kind == Kinds.VAR &&

                        s.owner.kind != Kinds.MTH)

                    isDecl = true;

            } else if (e.value.name == names.METHOD) {

                if (s.kind == Kinds.MTH &&

                        !s.isConstructor())

                    isDecl = true;

            } else if (e.value.name == names.PARAMETER) {

                if (s.kind == Kinds.VAR &&

                        s.owner.kind == Kinds.MTH &&

                        (s.flags() & Flags.PARAMETER) != 0)

                    isDecl = true;

            } else if (e.value.name == names.CONSTRUCTOR) {

                if (s.kind == Kinds.MTH &&

                        s.isConstructor())

                    isDecl = true;

            } else if (e.value.name == names.LOCAL_VARIABLE) {

                if (s.kind == Kinds.VAR &&

                        s.owner.kind == Kinds.MTH &&

                        (s.flags() & Flags.PARAMETER) == 0)

                    isDecl = true;

            } else if (e.value.name == names.ANNOTATION_TYPE) {

                if (s.kind == Kinds.TYP &&

                        (s.flags() & Flags.ANNOTATION) != 0)

                    isDecl = true;

            } else if (e.value.name == names.PACKAGE) {

                if (s.kind == Kinds.PCK)

                    isDecl = true;

            } else if (e.value.name == names.TYPE_USE) {

                if (s.kind == Kinds.TYP ||

                        s.kind == Kinds.VAR ||

                        (s.kind == Kinds.MTH && !s.isConstructor() &&

                        !s.type.getReturnType().hasTag(TypeTag.VOID)) ||

                        (s.kind == Kinds.MTH && s.isConstructor()))

                    isType = true;

            } else if (e.value.name == names.TYPE_PARAMETER) {

                /* Irrelevant in this case */

                // TYPE_PARAMETER doesn't aid in distinguishing between

                // Type annotations and declaration annotations on an

                // Element

            } else {

                Assert.error("annotationType(): unrecognized Attribute name " + e.value.name +

                        " (" + e.value.name.getClass() + ")");

                isDecl = true;

            }

        }

        if (isDecl && isType) {

            return AnnotationType.BOTH;

        } else if (isType) {

            return AnnotationType.TYPE;

        } else {

            return AnnotationType.DECLARATION;

        }

    }

    /** Infer the target annotation kind, if none is give.

     * We only infer declaration annotations.

     */

    private static AnnotationType inferTargetMetaInfo(Attribute.Compound a, Symbol s) {

        return AnnotationType.DECLARATION;

    }

    private class TypeAnnotationPositions extends TreeScanner {

        private final boolean sigOnly;

        TypeAnnotationPositions(boolean sigOnly) {

            this.sigOnly = sigOnly;

        }

        /*

         * When traversing the AST we keep the "frames" of visited

         * trees in order to determine the position of annotations.

         */

        private ListBuffer<JCTree> frames = new ListBuffer<>();

        protected void push(JCTree t) { frames = frames.prepend(t); }

        protected JCTree pop() { return frames.next(); }

        // could this be frames.elems.tail.head?

        private JCTree peek2() { return frames.toList().tail.head; }

        @Override

        public void scan(JCTree tree) {

            push(tree);

            super.scan(tree);

            pop();

        }

        /**

         * Separates type annotations from declaration annotations.

         * This step is needed because in certain locations (where declaration

         * and type annotations can be mixed, e.g. the type of a field)

         * we never build an JCAnnotatedType. This step finds these

         * annotations and marks them as if they were part of the type.

         */

        private void separateAnnotationsKinds(JCTree typetree, Type type, Symbol sym,

                TypeAnnotationPosition pos) {

            List<Attribute.Compound> annotations = sym.getRawAttributes();

            ListBuffer<Attribute.Compound> declAnnos = new ListBuffer<>();

            ListBuffer<Attribute.TypeCompound> typeAnnos = new ListBuffer<>();

            ListBuffer<Attribute.TypeCompound> onlyTypeAnnos = new ListBuffer<>();

            for (Attribute.Compound a : annotations) {

                switch (annotationType(a, sym)) {

                case DECLARATION:

                    declAnnos.append(a);

                    break;

                case BOTH: {

                    declAnnos.append(a);

                    Attribute.TypeCompound ta = toTypeCompound(a, pos);

                    typeAnnos.append(ta);

                    break;

                }

                case TYPE: {

                    Attribute.TypeCompound ta = toTypeCompound(a, pos);

                    typeAnnos.append(ta);

                    // Also keep track which annotations are only type annotations

                    onlyTypeAnnos.append(ta);

                    break;

                }

                }

            }

            sym.resetAnnotations();

            sym.setDeclarationAttributes(declAnnos.toList());

            if (typeAnnos.isEmpty()) {

                return;

            }

            List<Attribute.TypeCompound> typeAnnotations = typeAnnos.toList();

            if (type == null) {

                // When type is null, put the type annotations to the symbol.

                // This is used for constructor return annotations, for which

                // we use the type of the enclosing class.

                type = sym.getEnclosingElement().asType();

                // Declaration annotations are always allowed on constructor returns.

                // Therefore, use typeAnnotations instead of onlyTypeAnnos.

                type = typeWithAnnotations(typetree, type, typeAnnotations, typeAnnotations);

                // Note that we don't use the result, the call to

                // typeWithAnnotations side-effects the type annotation positions.

                // This is important for constructors of nested classes.

                sym.appendUniqueTypeAttributes(typeAnnotations);

                return;

            }

            // type is non-null and annotations are added to that type

            type = typeWithAnnotations(typetree, type, typeAnnotations, onlyTypeAnnos.toList());

            if (sym.getKind() == ElementKind.METHOD) {

                sym.type.asMethodType().restype = type;

            } else if (sym.getKind() == ElementKind.PARAMETER) {

                sym.type = type;

                if (sym.getQualifiedName().equals(names._this)) {

                    sym.owner.type.asMethodType().recvtype = type;

                    // note that the typeAnnotations will also be added to the owner below.

                } else {

                    MethodType methType = sym.owner.type.asMethodType();

                    List<VarSymbol> params = ((MethodSymbol)sym.owner).params;

                    List<Type> oldArgs = methType.argtypes;

                    ListBuffer<Type> newArgs = new ListBuffer<>();

                    while (params.nonEmpty()) {

                        if (params.head == sym) {

                            newArgs.add(type);

                        } else {

                            newArgs.add(oldArgs.head);

                        }

                        oldArgs = oldArgs.tail;

                        params = params.tail;

                    }

                    methType.argtypes = newArgs.toList();

                }

            } else {

                sym.type = type;

            }

            sym.appendUniqueTypeAttributes(typeAnnotations);

            if (sym.getKind() == ElementKind.PARAMETER ||

                sym.getKind() == ElementKind.LOCAL_VARIABLE ||

                sym.getKind() == ElementKind.RESOURCE_VARIABLE ||

                sym.getKind() == ElementKind.EXCEPTION_PARAMETER) {

                // Make sure all type annotations from the symbol are also

                // on the owner.

                sym.owner.appendUniqueTypeAttributes(sym.getRawTypeAttributes());

            }

        }

        // This method has a similar purpose as

        // {@link com.sun.tools.javac.parser.JavacParser.insertAnnotationsToMostInner(JCExpression, List<JCTypeAnnotation>, boolean)}

        // We found a type annotation in a declaration annotation position,

        // for example, on the return type.

        // Such an annotation is _not_ part of an JCAnnotatedType tree and we therefore

        // need to set its position explicitly.

        // The method returns a copy of type that contains these annotations.

        //

        // As a side effect the method sets the type annotation position of "annotations".

        // Note that it is assumed that all annotations share the same position.

        private Type typeWithAnnotations(final JCTree typetree, final Type type,

                final List<Attribute.TypeCompound> annotations,

                final List<Attribute.TypeCompound> onlyTypeAnnotations) {

            //         typetree, type, annotations, onlyTypeAnnotations);

            if (annotations.isEmpty()) {

                return type;

            }

            if (type.hasTag(TypeTag.ARRAY)) {

                Type toreturn;

                if (type.isAnnotated()) {

                    toreturn = tomodify.annotatedType(type.getAnnotationMirrors());

                } else {

                    toreturn = tomodify;

                }

                JCArrayTypeTree arTree = arrayTypeTree(typetree);

                ListBuffer<TypePathEntry> depth = new ListBuffer<>();

                depth = depth.append(TypePathEntry.ARRAY);

                while (arType.elemtype.hasTag(TypeTag.ARRAY)) {

                    if (arType.elemtype.isAnnotated()) {

                        Type aelemtype = arType.elemtype;

                        ArrayType prevToMod = tomodify;

                        prevToMod.elemtype = tomodify.annotatedType(arType.elemtype.getAnnotationMirrors());

                    } else {

                        arType = (Type.ArrayType) arType.elemtype;

                        tomodify = (Type.ArrayType) tomodify.elemtype;

                    }

                    arTree = arrayTypeTree(arTree.elemtype);

                    depth = depth.append(TypePathEntry.ARRAY);

                }

                Type arelemType = typeWithAnnotations(arTree.elemtype, arType.elemtype, annotations, onlyTypeAnnotations);

                tomodify.elemtype = arelemType;

                {

                    // All annotations share the same position; modify the first one.

                    Attribute.TypeCompound a = annotations.get(0);

                    TypeAnnotationPosition p = a.position;

                    p.location = p.location.prependList(depth.toList());

                }

                typetree.type = toreturn;

                return toreturn;

            } else if (type.hasTag(TypeTag.TYPEVAR)) {

                // Nothing to do for type variables.

                return type;

            } else if (type.getKind() == TypeKind.UNION) {

                // There is a TypeKind, but no TypeTag.

                JCTypeUnion tutree = (JCTypeUnion) typetree;

                JCExpression fst = tutree.alternatives.get(0);

                Type res = typeWithAnnotations(fst, fst.type, annotations, onlyTypeAnnotations);

                fst.type = res;

                // TODO: do we want to set res as first element in uct.alternatives?

                // UnionClassType uct = (com.sun.tools.javac.code.Type.UnionClassType)type;

                // Return the un-annotated union-type.

                return type;

            } else {

                Type enclTy = type;

                Element enclEl = type.asElement();

                JCTree enclTr = typetree;

                while (enclEl != null &&

                        enclEl.getKind() != ElementKind.PACKAGE &&

                        enclTy != null &&

                        enclTy.getKind() != TypeKind.NONE &&

                        enclTy.getKind() != TypeKind.ERROR &&

                        (enclTr.getKind() == JCTree.Kind.MEMBER_SELECT ||

                         enclTr.getKind() == JCTree.Kind.PARAMETERIZED_TYPE ||

                         enclTr.getKind() == JCTree.Kind.ANNOTATED_TYPE)) {

                    // Iterate also over the type tree, not just the type: the type is already

                    // completely resolved and we cannot distinguish where the annotation

                    // belongs for a nested type.

                    if (enclTr.getKind() == JCTree.Kind.MEMBER_SELECT) {

                        // only change encl in this case.

                        enclTy = enclTy.getEnclosingType();

                        enclEl = enclEl.getEnclosingElement();

                        enclTr = ((JCFieldAccess)enclTr).getExpression();

                    } else if (enclTr.getKind() == JCTree.Kind.PARAMETERIZED_TYPE) {

                        enclTr = ((JCTypeApply)enclTr).getType();

                    } else {

                        // only other option because of while condition

                        enclTr = ((JCAnnotatedType)enclTr).getUnderlyingType();

                    }

                }

                /** We are trying to annotate some enclosing type,

                 * but nothing more exists.

                 */

                if (enclTy != null &&

                        enclTy.hasTag(TypeTag.NONE)) {

                    switch (onlyTypeAnnotations.size()) {

                    case 0:

                        // Don't issue an error if all type annotations are

                        // also declaration annotations.

                        // If the annotations are also declaration annotations, they are

                        // illegal as type annotations but might be legal as declaration annotations.

                        // The normal declaration annotation checks make sure that the use is valid.

                        break;

                    case 1:

                        log.error(typetree.pos(), "cant.type.annotate.scoping.1",

                                onlyTypeAnnotations);

                        break;

                    default:

                        log.error(typetree.pos(), "cant.type.annotate.scoping",

                                onlyTypeAnnotations);

                    }

                    return type;