/*

 * Copyright (c) 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.

 *

 * 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 org.graalvm.compiler.phases.common.util;

import java.util.EnumSet;

import java.util.HashSet;

import java.util.Set;

import org.graalvm.compiler.graph.Graph.NodeEvent;

import org.graalvm.compiler.graph.Graph.NodeEventListener;

import org.graalvm.compiler.graph.Node;

import org.graalvm.compiler.graph.Node.IndirectCanonicalization;

/**

 * A simple {@link NodeEventListener} implementation that accumulates event nodes in a

 * {@link HashSet}.

 */

public class HashSetNodeEventListener extends NodeEventListener {

    private final EconomicSet<Node> nodes;

    private final Set<NodeEvent> filter;

    /**

     * Creates a {@link NodeEventListener} that collects nodes from all events.

     */

    public HashSetNodeEventListener() {

        this.nodes = EconomicSet.create(Equivalence.IDENTITY);

        this.filter = EnumSet.allOf(NodeEvent.class);

    }

    /**

     * Creates a {@link NodeEventListener} that collects nodes from all events that match a given

     * filter.

     */

    public HashSetNodeEventListener(Set<NodeEvent> filter) {

        this.nodes = EconomicSet.create(Equivalence.IDENTITY);

        this.filter = filter;

    }

    /**

     * Excludes a given event from those for which nodes are collected.

     */

    public HashSetNodeEventListener exclude(NodeEvent e) {

        filter.remove(e);

        return this;

    }

    @Override

    public void changed(NodeEvent e, Node node) {

        if (filter.contains(e)) {

            nodes.add(node);

            if (node instanceof IndirectCanonicalization) {

                for (Node usage : node.usages()) {

                    nodes.add(usage);

                }

            }

        }

    }

    /**

     * Gets the set being used to accumulate the nodes communicated to this listener.

     */

    public EconomicSet<Node> getNodes() {

        return nodes;

    }

}