1/*
2 * Copyright (c) 2015, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23package org.graalvm.compiler.graph;
24
25import java.util.Map;
26import java.util.function.Consumer;
27
28/**
29 * This class is a container of a graph that needs to be readonly and optionally a lazily created
30 * mutable copy of the graph.
31 */
32public final class CachedGraph<G extends Graph> {
33
34    private final G readonlyCopy;
35    private G mutableCopy;
36
37    private CachedGraph(G readonlyCopy, G mutableCopy) {
38        this.readonlyCopy = readonlyCopy;
39        this.mutableCopy = mutableCopy;
40    }
41
42    public static <G extends Graph> CachedGraph<G> fromReadonlyCopy(G graph) {
43        return new CachedGraph<>(graph, null);
44    }
45
46    public static <G extends Graph> CachedGraph<G> fromMutableCopy(G graph) {
47        return new CachedGraph<>(graph, graph);
48    }
49
50    public G getReadonlyCopy() {
51        if (hasMutableCopy()) {
52            return mutableCopy;
53        }
54        return readonlyCopy;
55    }
56
57    public boolean hasMutableCopy() {
58        return mutableCopy != null;
59    }
60
61    @SuppressWarnings("unchecked")
62    public G getMutableCopy(Consumer<Map<Node, Node>> duplicationMapCallback) {
63        if (!hasMutableCopy()) {
64            mutableCopy = (G) readonlyCopy.copy(duplicationMapCallback);
65        }
66        return mutableCopy;
67    }
68}
69