/*
 * 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.code.Attribute.TypeCompound;
import com.sun.tools.javac.code.Kinds.Kind;
import com.sun.tools.javac.util.Assert;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.ListBuffer;

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().
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.
/**
 * 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.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.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.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());
        if ((sym.flags() & Flags.BRIDGE) != 0) {
            Assert.check(other.sym.kind == Kind.MTH);
            ListBuffer<TypeCompound> typeAttributes = new ListBuffer<>();
            for (TypeCompound tc : other.getTypeAttributes()) {
                // Carry over only contractual type annotations: i.e nothing interior to method body.
                if (!tc.position.type.isLocal())
                    typeAttributes.append(tc);
            }
            setTypeAttributes(typeAttributes.toList());
        } else {
            setTypeAttributes(other.getTypeAttributes());
        }
        if (sym.kind == Kind.TYP) {
            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.nil()
                : a;
    }

    private boolean isStarted() {
        return attributes != DECL_NOT_STARTED;
    }
}