1 /* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.dx.dex.file; 18 19 import com.android.dx.rop.cst.Constant; 20 import com.android.dx.rop.cst.CstType; 21 import com.android.dx.rop.type.Type; 22 import com.android.dx.rop.type.TypeList; 23 import com.android.dx.util.AnnotatedOutput; 24 import com.android.dx.util.Hex; 25 import java.util.ArrayList; 26 import java.util.Collection; 27 import java.util.TreeMap; 28 29 /** 30 * Class definitions list section of a {@code .dex} file. 31 */ 32 public final class ClassDefsSection extends UniformItemSection { 33 /** 34 * {@code non-null;} map from type constants for classes to {@link 35 * ClassDefItem} instances that define those classes 36 */ 37 private final TreeMap<Type, ClassDefItem> classDefs; 38 39 /** {@code null-ok;} ordered list of classes; set in {@link #orderItems} */ 40 private ArrayList<ClassDefItem> orderedDefs; 41 42 /** 43 * Constructs an instance. The file offset is initially unknown. 44 * 45 * @param file {@code non-null;} file that this instance is part of 46 */ 47 public ClassDefsSection(DexFile file) { 48 super("class_defs", file, 4); 49 50 classDefs = new TreeMap<Type, ClassDefItem>(); 51 orderedDefs = null; 52 } 53 54 /** {@inheritDoc} */ 55 @Override 56 public Collection<? extends Item> items() { 57 if (orderedDefs != null) { 58 return orderedDefs; 59 } 60 61 return classDefs.values(); 62 } 63 64 /** {@inheritDoc} */ 65 @Override 66 public IndexedItem get(Constant cst) { 67 if (cst == null) { 68 throw new NullPointerException("cst == null"); 69 } 70 71 throwIfNotPrepared(); 72 73 Type type = ((CstType) cst).getClassType(); 74 IndexedItem result = classDefs.get(type); 75 76 if (result == null) { 77 throw new IllegalArgumentException("not found"); 78 } 79 80 return result; 81 } 82 83 /** 84 * Writes the portion of the file header that refers to this instance. 85 * 86 * @param out {@code non-null;} where to write 87 */ 88 public void writeHeaderPart(AnnotatedOutput out) { 89 throwIfNotPrepared(); 90 91 int sz = classDefs.size(); 92 int offset = (sz == 0) ? 0 : getFileOffset(); 93 94 if (out.annotates()) { 95 out.annotate(4, "class_defs_size: " + Hex.u4(sz)); 96 out.annotate(4, "class_defs_off: " + Hex.u4(offset)); 97 } 98 99 out.writeInt(sz); 100 out.writeInt(offset); 101 } 102 103 /** 104 * Adds an element to this instance. It is illegal to attempt to add more 105 * than one class with the same name. 106 * 107 * @param clazz {@code non-null;} the class def to add 108 */ 109 public void add(ClassDefItem clazz) { 110 Type type; 111 112 try { 113 type = clazz.getThisClass().getClassType(); 114 } catch (NullPointerException ex) { 115 // Elucidate the exception. 116 throw new NullPointerException("clazz == null"); 117 } 118 119 throwIfPrepared(); 120 121 if (classDefs.get(type) != null) { 122 throw new IllegalArgumentException("already added: " + type); 123 } 124 125 classDefs.put(type, clazz); 126 } 127 128 /** {@inheritDoc} */ 129 @Override 130 protected void orderItems() { 131 int sz = classDefs.size(); 132 int idx = 0; 133 134 orderedDefs = new ArrayList<ClassDefItem>(sz); 135 136 /* 137 * Iterate over all the classes, recursively assigning an 138 * index to each, implicitly skipping the ones that have 139 * already been assigned by the time this (top-level) 140 * iteration reaches them. 141 */ 142 for (Type type : classDefs.keySet()) { 143 idx = orderItems0(type, idx, sz - idx); 144 } 145 } 146 147 /** 148 * Helper for {@link #orderItems}, which recursively assigns indices 149 * to classes. 150 * 151 * @param type {@code null-ok;} type ref to assign, if any 152 * @param idx {@code >= 0;} the next index to assign 153 * @param maxDepth maximum recursion depth; if negative, this will 154 * throw an exception indicating class definition circularity 155 * @return {@code >= 0;} the next index to assign 156 */ 157 private int orderItems0(Type type, int idx, int maxDepth) { 158 ClassDefItem c = classDefs.get(type); 159 160 if ((c == null) || (c.hasIndex())) { 161 return idx; 162 } 163 164 if (maxDepth < 0) { 165 throw new RuntimeException("class circularity with " + type); 166 } 167 168 maxDepth--; 169 170 CstType superclassCst = c.getSuperclass(); 171 if (superclassCst != null) { 172 Type superclass = superclassCst.getClassType(); 173 idx = orderItems0(superclass, idx, maxDepth); 174 } 175 176 TypeList interfaces = c.getInterfaces(); 177 int sz = interfaces.size(); 178 for (int i = 0; i < sz; i++) { 179 idx = orderItems0(interfaces.getType(i), idx, maxDepth); 180 } 181 182 c.setIndex(idx); 183 orderedDefs.add(c); 184 return idx + 1; 185 } 186 } 187