Node.java revision 1263:044a0fe3944f
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.ir; 27 28import java.io.Serializable; 29import java.util.ArrayList; 30import java.util.List; 31import jdk.nashorn.internal.ir.visitor.NodeVisitor; 32import jdk.nashorn.internal.parser.Token; 33import jdk.nashorn.internal.parser.TokenType; 34 35/** 36 * Nodes are used to compose Abstract Syntax Trees. 37 */ 38public abstract class Node implements Cloneable, Serializable { 39 private static final long serialVersionUID = 1L; 40 41 /** Constant used for synthetic AST nodes that have no line number. */ 42 public static final int NO_LINE_NUMBER = -1; 43 44 /** Constant used for synthetic AST nodes that have no token. */ 45 public static final long NO_TOKEN = 0L; 46 47 /** Constant used for synthetic AST nodes that have no finish. */ 48 public static final int NO_FINISH = 0; 49 50 /** Start of source range. */ 51 protected final int start; 52 53 /** End of source range. */ 54 protected final int finish; 55 56 /** Token descriptor. */ 57 private final long token; 58 59 /** 60 * Constructor 61 * 62 * @param token token 63 * @param finish finish 64 */ 65 public Node(final long token, final int finish) { 66 this.token = token; 67 this.start = Token.descPosition(token); 68 this.finish = finish; 69 } 70 71 /** 72 * Constructor 73 * 74 * @param token token 75 * @param start start 76 * @param finish finish 77 */ 78 protected Node(final long token, final int start, final int finish) { 79 this.start = start; 80 this.finish = finish; 81 this.token = token; 82 } 83 84 /** 85 * Copy constructor 86 * 87 * @param node source node 88 */ 89 protected Node(final Node node) { 90 this.token = node.token; 91 this.start = node.start; 92 this.finish = node.finish; 93 } 94 95 /** 96 * Copy constructor that overrides finish 97 * 98 * @param node source node 99 * @param finish Last character 100 */ 101 protected Node(final Node node, final int finish) { 102 this.token = node.token; 103 this.start = node.start; 104 this.finish = finish; 105 } 106 107 /** 108 * Is this a loop node? 109 * 110 * @return true if atom 111 */ 112 public boolean isLoop() { 113 return false; 114 } 115 116 /** 117 * Is this an assignment node - for example a var node with an init 118 * or a binary node that writes to a destination 119 * 120 * @return true if assignment 121 */ 122 public boolean isAssignment() { 123 return false; 124 } 125 126 /** 127 * For reference copies - ensure that labels in the copy node are unique 128 * using an appropriate copy constructor 129 * @param lc lexical context 130 * @return new node or same of no labels 131 */ 132 public Node ensureUniqueLabels(final LexicalContext lc) { 133 return this; 134 } 135 136 /** 137 * Provides a means to navigate the IR. 138 * @param visitor Node visitor. 139 * @return node the node or its replacement after visitation, null if no further visitations are required 140 */ 141 public abstract Node accept(NodeVisitor<? extends LexicalContext> visitor); 142 143 @Override 144 public String toString() { 145 final StringBuilder sb = new StringBuilder(); 146 toString(sb); 147 return sb.toString(); 148 } 149 150 /** 151 * String conversion helper. Fills a {@link StringBuilder} with the 152 * string version of this node 153 * 154 * @param sb a StringBuilder 155 */ 156 public void toString(final StringBuilder sb) { 157 toString(sb, true); 158 } 159 160 /** 161 * Print logic that decides whether to show the optimistic type 162 * or not - for example it should not be printed after just parse, 163 * when it hasn't been computed, or has been set to a trivially provable 164 * value 165 * @param sb string builder 166 * @param printType print type? 167 */ 168 public abstract void toString(final StringBuilder sb, final boolean printType); 169 170 /** 171 * Get the finish position for this node in the source string 172 * @return finish 173 */ 174 public int getFinish() { 175 return finish; 176 } 177 178 /** 179 * Get start position for node 180 * @return start position 181 */ 182 public int getStart() { 183 return start; 184 } 185 186 /** 187 * Integer to sort nodes in source order. This order is 188 * used by parser API to sort statements in correct order. 189 * By default, this is the start position of this node. 190 * 191 * @return int code to sort this node. 192 */ 193 public int getSourceOrder() { 194 return getStart(); 195 } 196 197 @Override 198 protected Object clone() { 199 try { 200 return super.clone(); 201 } catch (final CloneNotSupportedException e) { 202 throw new AssertionError(e); 203 } 204 } 205 206 @Override 207 public final boolean equals(final Object other) { 208 return this == other; 209 } 210 211 @Override 212 public final int hashCode() { 213 // NOTE: we aren't delegating to Object.hashCode as it still requires trip to the VM for initializing, 214 // it touches the object header and/or stores the identity hashcode somewhere, etc. There's several 215 // places in the compiler pipeline that store nodes in maps, so this can get hot. 216 return Long.hashCode(token); 217 } 218 219 /** 220 * Return token position from a token descriptor. 221 * 222 * @return Start position of the token in the source. 223 */ 224 public int position() { 225 return Token.descPosition(token); 226 } 227 228 /** 229 * Return token length from a token descriptor. 230 * 231 * @return Length of the token. 232 */ 233 public int length() { 234 return Token.descLength(token); 235 } 236 237 /** 238 * Returns this node's token's type. If you want to check for the node having a specific token type, 239 * consider using {@link #isTokenType(TokenType)} instead. 240 * 241 * @return type of token. 242 */ 243 public TokenType tokenType() { 244 return Token.descType(token); 245 } 246 247 /** 248 * Tests if this node has the specific token type. 249 * 250 * @param type a token type to check this node's token type against 251 * @return true if token types match. 252 */ 253 public boolean isTokenType(final TokenType type) { 254 return tokenType() == type; 255 } 256 257 /** 258 * Get the token for this node. If you want to retrieve the token's type, consider using 259 * {@link #tokenType()} or {@link #isTokenType(TokenType)} instead. 260 * @return the token 261 */ 262 public long getToken() { 263 return token; 264 } 265 266 //on change, we have to replace the entire list, that's we can't simple do ListIterator.set 267 static <T extends Node> List<T> accept(final NodeVisitor<? extends LexicalContext> visitor, final List<T> list) { 268 final int size = list.size(); 269 if (size == 0) { 270 return list; 271 } 272 273 List<T> newList = null; 274 275 for (int i = 0; i < size; i++) { 276 final T node = list.get(i); 277 @SuppressWarnings("unchecked") 278 final T newNode = node == null ? null : (T)node.accept(visitor); 279 if (newNode != node) { 280 if (newList == null) { 281 newList = new ArrayList<>(size); 282 for (int j = 0; j < i; j++) { 283 newList.add(list.get(j)); 284 } 285 } 286 newList.add(newNode); 287 } else { 288 if (newList != null) { 289 newList.add(node); 290 } 291 } 292 } 293 294 return newList == null ? list : newList; 295 } 296 297 static <T extends LexicalContextNode> T replaceInLexicalContext(final LexicalContext lc, final T oldNode, final T newNode) { 298 if (lc != null) { 299 lc.replace(oldNode, newNode); 300 } 301 return newNode; 302 } 303} 304