001/*
002 * Copyright (c) 2015, 2015, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.
008 *
009 * This code is distributed in the hope that it will be useful, but WITHOUT
010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
011 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
012 * version 2 for more details (a copy is included in the LICENSE file that
013 * accompanied this code).
014 *
015 * You should have received a copy of the GNU General Public License version
016 * 2 along with this work; if not, write to the Free Software Foundation,
017 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
018 *
019 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
020 * or visit www.oracle.com if you need additional information or have any
021 * questions.
022 */
023package com.oracle.graal.graph;
024
025import java.util.*;
026import java.util.function.*;
027
028/**
029 * This class is a container of a graph that needs to be readonly and optionally a lazily created
030 * mutable copy of the graph.
031 */
032public final class CachedGraph<G extends Graph> {
033
034    private final G readonlyCopy;
035    private G mutableCopy;
036
037    private CachedGraph(G readonlyCopy, G mutableCopy) {
038        this.readonlyCopy = readonlyCopy;
039        this.mutableCopy = mutableCopy;
040    }
041
042    public static <G extends Graph> CachedGraph<G> fromReadonlyCopy(G graph) {
043        return new CachedGraph<>(graph, null);
044    }
045
046    public static <G extends Graph> CachedGraph<G> fromMutableCopy(G graph) {
047        return new CachedGraph<>(graph, graph);
048    }
049
050    public G getReadonlyCopy() {
051        if (hasMutableCopy()) {
052            return mutableCopy;
053        }
054        return readonlyCopy;
055    }
056
057    public boolean hasMutableCopy() {
058        return mutableCopy != null;
059    }
060
061    @SuppressWarnings("unchecked")
062    public G getMutableCopy(Consumer<Map<Node, Node>> duplicationMapCallback) {
063        if (!hasMutableCopy()) {
064            mutableCopy = (G) readonlyCopy.copy(duplicationMapCallback);
065        }
066        return mutableCopy;
067    }
068}