1 /* 2 * Copyright (c) 2014, 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.core.common; 24 25 import static org.graalvm.compiler.core.common.UnsafeAccess.UNSAFE; 26 27 import java.lang.reflect.Field; 28 import java.lang.reflect.Modifier; 29 import java.util.ArrayList; 30 31 import sun.misc.Unsafe; 32 33 /** 34 * Scans the fields in a class hierarchy. 35 */ 36 public class FieldsScanner { 37 38 /** 39 * Determines the offset (in bytes) of a field. 40 */ 41 public interface CalcOffset { 42 43 long getOffset(Field field); 44 } 45 46 /** 47 * Determines the offset (in bytes) of a field using {@link Unsafe#objectFieldOffset(Field)}. 48 */ 49 public static class DefaultCalcOffset implements CalcOffset { 50 51 @Override 52 public long getOffset(Field field) { 53 return UNSAFE.objectFieldOffset(field); 54 } 55 } 56 57 /** 58 * Describes a field in a class during {@linkplain FieldsScanner scanning}. 59 */ 60 public static class FieldInfo implements Comparable<FieldInfo> { 61 public final long offset; 62 public final String name; 63 public final Class<?> type; 64 public final Class<?> declaringClass; 65 66 public FieldInfo(long offset, String name, Class<?> type, Class<?> declaringClass) { 67 this.offset = offset; 68 this.name = name; 69 this.type = type; 70 this.declaringClass = declaringClass; 71 } 72 73 /** 74 * Sorts fields in ascending order by their {@link #offset}s. 75 */ 76 @Override 77 public int compareTo(FieldInfo o) { 78 return offset < o.offset ? -1 : (offset > o.offset ? 1 : 0); 79 } 80 81 @Override 82 public String toString() { 83 return "[" + offset + "]" + name + ":" + type.getSimpleName(); 84 } 85 } 86 87 private final FieldsScanner.CalcOffset calc; 88 89 /** 90 * Fields not belonging to a more specific category defined by scanner subclasses are added to 91 * this list. 92 */ 93 public final ArrayList<FieldsScanner.FieldInfo> data = new ArrayList<>(); 94 95 public FieldsScanner(FieldsScanner.CalcOffset calc) { 96 this.calc = calc; 97 } 98 99 /** 100 * Scans the fields in a class hierarchy. 101 * 102 * @param clazz the class at which to start scanning 103 * @param endClazz scanning stops when this class is encountered (i.e. {@code endClazz} is not 104 * scanned) 105 */ 106 public void scan(Class<?> clazz, Class<?> endClazz, boolean includeTransient) { 107 Class<?> currentClazz = clazz; 108 while (currentClazz != endClazz) { 109 for (Field field : currentClazz.getDeclaredFields()) { 110 if (Modifier.isStatic(field.getModifiers())) { 111 continue; 112 } 113 if (!includeTransient && Modifier.isTransient(field.getModifiers())) { 114 continue; 115 } 116 long offset = calc.getOffset(field); 117 scanField(field, offset); 118 } 119 currentClazz = currentClazz.getSuperclass(); 120 } 121 } 122 123 protected void scanField(Field field, long offset) { 124 data.add(new FieldsScanner.FieldInfo(offset, field.getName(), field.getType(), field.getDeclaringClass())); 125 } 126 }