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.Map;
  26 import 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  */
  32 public 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 }