/*

 * Copyright (c) 2012, 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 com.sun.tools.javac.util.Assert;

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

/**

 * Container for all annotations (attributes in javac) on a Symbol.

 *

 * This class is explicitly mutable. Its contents will change when attributes

 * are annotated onto the Symbol. However this class depends on the facts that

 * List (in javac) is immutable.

 *

 * An instance of this class can be in one of three states:

 *

 * NOT_STARTED indicates that the Symbol this instance belongs to has not been

 * annotated (yet). Specifically if the declaration is not annotated this

 * instance will never move past NOT_STARTED. You can never go back to

 * NOT_STARTED.

 *

 * IN_PROGRESS annotations have been found on the declaration. Will be processed

 * later. You can reset to IN_PROGRESS. While IN_PROGRESS you can set the list

 * of attributes (and this moves out of the IN_PROGRESS state).

 *

 * "unnamed" this SymbolMetadata contains some attributes, possibly the final set.

 * While in this state you can only prepend or append to the attributes not set

 * it directly. You can also move back to the IN_PROGRESS state using reset().

 *

 * <p><b>This is NOT part of any supported API. If you write code that depends

 * on this, you do so at your own risk. This code and its internal interfaces

 * are subject to change or deletion without notice.</b>

 */

public class SymbolMetadata {

    private static final List<Attribute.Compound> DECL_NOT_STARTED = List.of(null);

    private static final List<Attribute.Compound> DECL_IN_PROGRESS = List.of(null);

    /*

     * This field should never be null

     */

    private List<Attribute.Compound> attributes = DECL_NOT_STARTED;

    /*

     * Type attributes for this symbol.

     * This field should never be null.

     */

    private List<Attribute.TypeCompound> type_attributes = List.<Attribute.TypeCompound>nil();

    /*

     * Type attributes of initializers in this class.

     * Unused if the current symbol is not a ClassSymbol.

     */

    private List<Attribute.TypeCompound> init_type_attributes = List.<Attribute.TypeCompound>nil();

    /*

     * Type attributes of class initializers in this class.

     * Unused if the current symbol is not a ClassSymbol.

     */

    private List<Attribute.TypeCompound> clinit_type_attributes = List.<Attribute.TypeCompound>nil();

    /*

     * The Symbol this SymbolMetadata instance belongs to

     */

    private final Symbol sym;

    public SymbolMetadata(Symbol sym) {

        this.sym = sym;

    }

    public List<Attribute.Compound> getDeclarationAttributes() {

        return filterDeclSentinels(attributes);

    }

    public List<Attribute.TypeCompound> getTypeAttributes() {

        return type_attributes;

    }

    public List<Attribute.TypeCompound> getInitTypeAttributes() {

        return init_type_attributes;

    }

    public List<Attribute.TypeCompound> getClassInitTypeAttributes() {

        return clinit_type_attributes;

    }

    public void setDeclarationAttributes(List<Attribute.Compound> a) {

        Assert.check(pendingCompletion() || !isStarted());

        if (a == null) {

            throw new NullPointerException();

        }

        attributes = a;

    }

    public void setTypeAttributes(List<Attribute.TypeCompound> a) {

        if (a == null) {

            throw new NullPointerException();

        }

        type_attributes = a;

    }

    public void setInitTypeAttributes(List<Attribute.TypeCompound> a) {

        if (a == null) {

            throw new NullPointerException();

        }

        init_type_attributes = a;

    }

    public void setClassInitTypeAttributes(List<Attribute.TypeCompound> a) {

        if (a == null) {

            throw new NullPointerException();

        }

        clinit_type_attributes = a;

    }

    public void setAttributes(SymbolMetadata other) {

        if (other == null) {

            throw new NullPointerException();

        }

        setDeclarationAttributes(other.getDeclarationAttributes());

        setTypeAttributes(other.getTypeAttributes());

        setInitTypeAttributes(other.getInitTypeAttributes());

        setClassInitTypeAttributes(other.getClassInitTypeAttributes());

    }

    public SymbolMetadata reset() {

        attributes = DECL_IN_PROGRESS;

        return this;

    }

    public boolean isEmpty() {

        return !isStarted()

                || pendingCompletion()

                || attributes.isEmpty();

    }

    public boolean isTypesEmpty() {

        return type_attributes.isEmpty();

    }

    public boolean pendingCompletion() {

        return attributes == DECL_IN_PROGRESS;

    }

    public SymbolMetadata append(List<Attribute.Compound> l) {

        attributes = filterDeclSentinels(attributes);

        if (l.isEmpty()) {

            // no-op

        } else if (attributes.isEmpty()) {

            attributes = l;

        } else {

            attributes = attributes.appendList(l);

        }

        return this;

    }

    public SymbolMetadata appendUniqueTypes(List<Attribute.TypeCompound> l) {

        if (l.isEmpty()) {

            // no-op

        } else if (type_attributes.isEmpty()) {

            type_attributes = l;

        } else {

            // TODO: in case we expect a large number of annotations, this

            // might be inefficient.

            for (Attribute.TypeCompound tc : l) {

                if (!type_attributes.contains(tc))

                    type_attributes = type_attributes.append(tc);

            }

        }

        return this;

    }

    public SymbolMetadata appendInitTypeAttributes(List<Attribute.TypeCompound> l) {

        if (l.isEmpty()) {

            // no-op

        } else if (init_type_attributes.isEmpty()) {

            init_type_attributes = l;

        } else {

            init_type_attributes = init_type_attributes.appendList(l);

        }

        return this;

    }

    public SymbolMetadata appendClassInitTypeAttributes(List<Attribute.TypeCompound> l) {

        if (l.isEmpty()) {

            // no-op

        } else if (clinit_type_attributes.isEmpty()) {

            clinit_type_attributes = l;

        } else {

            clinit_type_attributes = clinit_type_attributes.appendList(l);

        }

        return this;

    }

    public SymbolMetadata prepend(List<Attribute.Compound> l) {

        attributes = filterDeclSentinels(attributes);

        if (l.isEmpty()) {

            // no-op

        } else if (attributes.isEmpty()) {

            attributes = l;

        } else {

            attributes = attributes.prependList(l);

        }

        return this;

    }

    private List<Attribute.Compound> filterDeclSentinels(List<Attribute.Compound> a) {

        return (a == DECL_IN_PROGRESS || a == DECL_NOT_STARTED)

                ? List.<Attribute.Compound>nil()

                : a;

    }

    private boolean isStarted() {

        return attributes != DECL_NOT_STARTED;

    }

}