1/*
2 * Copyright 2013, Google Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met:
8 *
9 *     * Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *     * Redistributions in binary form must reproduce the above
12 * copyright notice, this list of conditions and the following disclaimer
13 * in the documentation and/or other materials provided with the
14 * distribution.
15 *     * Neither the name of Google Inc. nor the names of its
16 * contributors may be used to endorse or promote products derived from
17 * this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32package org.jf.dexlib2.analysis.util;
33
34import org.jf.dexlib2.analysis.TypeProto;
35import org.jf.dexlib2.analysis.UnresolvedClassException;
36
37import javax.annotation.Nonnull;
38import javax.annotation.Nullable;
39import java.util.Iterator;
40import java.util.NoSuchElementException;
41
42public class TypeProtoUtils {
43    /**
44     * Get the chain of superclasses of the given class. The first element will be the immediate superclass followed by
45     * it's superclass, etc. up to java.lang.Object.
46     *
47     * Returns an empty iterable if called on java.lang.Object or a primitive.
48     *
49     * If any class in the superclass chain can't be resolved, the iterable will return Ujava/lang/Object; to represent
50     * the unknown class.
51     *
52     * @return An iterable containing the superclasses of this class.
53     */
54    @Nonnull
55    public static Iterable<TypeProto> getSuperclassChain(@Nonnull final TypeProto typeProto) {
56        return new Iterable<TypeProto>() {
57
58            @Override public Iterator<TypeProto> iterator() {
59                return new Iterator<TypeProto>() {
60                    @Nullable private TypeProto type = getSuperclassAsTypeProto(typeProto);
61
62                    @Override public boolean hasNext() {
63                        return type != null;
64                    }
65
66                    @Override public TypeProto next() {
67                        TypeProto type = this.type;
68                        if (type == null) {
69                            throw new NoSuchElementException();
70                        }
71
72                        this.type = getSuperclassAsTypeProto(type);
73                        return type;
74                    }
75
76                    @Override public void remove() {
77                        throw new UnsupportedOperationException();
78                    }
79                };
80            }
81        };
82    }
83
84    @Nullable
85    public static TypeProto getSuperclassAsTypeProto(@Nonnull TypeProto type) {
86        try {
87            String next = type.getSuperclass();
88            if (next != null) {
89                return type.getClassPath().getClass(next);
90            } else {
91                return null;
92            }
93        } catch (UnresolvedClassException ex) {
94            return type.getClassPath().getUnknownClass();
95        }
96    }
97
98    public static boolean extendsFrom(@Nonnull TypeProto candidate, @Nonnull String possibleSuper) {
99        if (candidate.getType().equals(possibleSuper)) {
100            return true;
101        }
102        for (TypeProto superProto: getSuperclassChain(candidate)) {
103            if (superProto.getType().equals(possibleSuper)) {
104                return true;
105            }
106        }
107        return false;
108    }
109}
110