1/* 2 * Copyright (c) 2010, 2013, 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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26package jdk.nashorn.internal.codegen; 27 28import static jdk.nashorn.internal.codegen.MethodEmitter.LARGE_STRING_THRESHOLD; 29 30import java.util.HashMap; 31 32/** 33 * A name space hierarchy, where each level holds a name directory with 34 * names that may be unique for each level. 35 */ 36 37public class Namespace { 38 /** Parent namespace. */ 39 private final Namespace parent; 40 41 /** Name directory - version count for each name */ 42 private final HashMap<String, Integer> directory; 43 44 /** 45 * Constructor 46 */ 47 public Namespace() { 48 this(null); 49 } 50 51 /** 52 * Constructor 53 * 54 * @param parent parent name space 55 */ 56 public Namespace(final Namespace parent) { 57 this.parent = parent; 58 this.directory = new HashMap<>(); 59 } 60 61 /** 62 * Return the parent Namespace of this space. 63 * 64 * @return parent name space 65 */ 66 public Namespace getParent() { 67 return parent; 68 } 69 70 /** 71 * Create a uniqueName name in the namespace in the form base-n where n varies. 72 * Also truncates very long names that would otherwise break ASM. 73 * 74 * @param base Base of name. Base will be returned if uniqueName. 75 * @return Generated uniqueName name. 76 */ 77 public String uniqueName(final String base) { 78 final String truncatedBase = base.length() > LARGE_STRING_THRESHOLD ? base.substring(0, LARGE_STRING_THRESHOLD) : base; 79 for (Namespace namespace = this; namespace != null; namespace = namespace.getParent()) { 80 final HashMap<String, Integer> namespaceDirectory = namespace.directory; 81 final Integer counter = namespaceDirectory.get(truncatedBase); 82 83 if (counter != null) { 84 final int count = counter + 1; 85 namespaceDirectory.put(truncatedBase, count); 86 return truncatedBase + CompilerConstants.ID_FUNCTION_SEPARATOR.symbolName() + count; 87 } 88 } 89 90 directory.put(truncatedBase, 0); 91 92 return truncatedBase; 93 } 94 95 @Override 96 public String toString() { 97 return directory.toString(); 98 } 99} 100