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  */
  23 package org.graalvm.compiler.graph;
  24 
  25 import java.util.function.Consumer;
  26 
  27 import org.graalvm.util.UnmodifiableEconomicMap;
  28 
  29 /**
  30  * This class is a container of a graph that needs to be readonly and optionally a lazily created
  31  * mutable copy of the graph.
  32  */
  33 public final class CachedGraph<G extends Graph> {
  34 
  35     private final G readonlyCopy;
  36     private G mutableCopy;
  37 
  38     private CachedGraph(G readonlyCopy, G mutableCopy) {
  39         this.readonlyCopy = readonlyCopy;
  40         this.mutableCopy = mutableCopy;
  41     }
  42 
  43     public static <G extends Graph> CachedGraph<G> fromReadonlyCopy(G graph) {
  44         return new CachedGraph<>(graph, null);
  45     }
  46 
  47     public static <G extends Graph> CachedGraph<G> fromMutableCopy(G graph) {
  48         return new CachedGraph<>(graph, graph);
  49     }
  50 
  51     public G getReadonlyCopy() {
  52         if (hasMutableCopy()) {
  53             return mutableCopy;
  54         }
  55         return readonlyCopy;
  56     }
  57 
  58     public boolean hasMutableCopy() {
  59         return mutableCopy != null;
  60     }
  61 
  62     @SuppressWarnings("unchecked")
  63     public G getMutableCopy(Consumer<UnmodifiableEconomicMap<Node, Node>> duplicationMapCallback) {
  64         if (!hasMutableCopy()) {
  65             mutableCopy = (G) readonlyCopy.copy(duplicationMapCallback);
  66         }
  67         return mutableCopy;
  68     }
  69 }