DexBackedField.java revision 12b970ed4dfad768002335503e49c348ea0ed69b 
1/*
2 * Copyright 2012, 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.dexbacked;
33
34import org.jf.dexlib2.base.reference.BaseFieldReference;
35import org.jf.dexlib2.dexbacked.util.AnnotationsDirectory;
36import org.jf.dexlib2.dexbacked.util.StaticInitialValueIterator;
37import org.jf.dexlib2.iface.ClassDef;
38import org.jf.dexlib2.iface.Field;
39import org.jf.dexlib2.iface.value.EncodedValue;
40
41import javax.annotation.Nonnull;
42import javax.annotation.Nullable;
43import java.util.List;
44
45public class DexBackedField extends BaseFieldReference implements Field {
46    @Nonnull public final DexBuffer dexBuf;
47    @Nonnull public final ClassDef classDef;
48
49    public final int accessFlags;
50    @Nullable public final EncodedValue initialValue;
51    public final int annotationSetOffset;
52
53    public final int fieldIndex;
54
55    private int fieldIdItemOffset;
56
57    // offsets for field_id_item
58    private static final int TYPE_OFFSET = 2;
59    private static final int NAME_OFFSET = 4;
60
61    public DexBackedField(@Nonnull DexReader reader,
62                          @Nonnull DexBackedClassDef classDef,
63                          int previousFieldIndex,
64                          @Nonnull StaticInitialValueIterator staticInitialValueIterator,
65                          @Nonnull AnnotationsDirectory.AnnotationIterator annotationIterator) {
66        this.dexBuf = reader.getDexBuffer();
67        this.classDef = classDef;
68
69        int fieldIndexDiff = reader.readSmallUleb128();
70        this.fieldIndex = fieldIndexDiff + previousFieldIndex;
71        this.accessFlags = reader.readSmallUleb128();
72
73        this.annotationSetOffset = annotationIterator.seekTo(fieldIndex);
74        this.initialValue = staticInitialValueIterator.getNextOrNull();
75    }
76
77    @Nonnull
78    @Override
79    public String getName() {
80        return dexBuf.getString(dexBuf.readSmallUint(getFieldIdItemOffset() + NAME_OFFSET));
81    }
82
83    @Nonnull
84    @Override
85    public String getType() {
86        return dexBuf.getType(dexBuf.readUshort(getFieldIdItemOffset() + TYPE_OFFSET));
87    }
88
89    @Nonnull @Override public String getContainingClass() { return classDef.getType(); }
90    @Override public int getAccessFlags() { return accessFlags; }
91    @Nullable @Override public EncodedValue getInitialValue() { return initialValue; }
92
93    @Nonnull
94    @Override
95    public List<? extends DexBackedAnnotation> getAnnotations() {
96        return AnnotationsDirectory.getAnnotations(dexBuf, annotationSetOffset);
97    }
98
99    /**
100     * Skips the reader over the specified number of encoded_field structures
101     *
102     * @param reader The reader to skip
103     * @param count The number of encoded_field structures to skip over
104     */
105    public static void skipAllFields(@Nonnull DexReader reader, int count) {
106        for (int i=0; i<count; i++) {
107            reader.skipUleb128();
108            reader.skipUleb128();
109        }
110    }
111
112    private int getFieldIdItemOffset() {
113        if (fieldIdItemOffset == 0) {
114            fieldIdItemOffset = dexBuf.getFieldIdItemOffset(fieldIndex);
115        }
116        return fieldIdItemOffset;
117    }
118}
119