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.raw.FieldIdItem;
36import org.jf.dexlib2.dexbacked.util.AnnotationsDirectory;
37import org.jf.dexlib2.dexbacked.util.StaticInitialValueIterator;
38import org.jf.dexlib2.iface.ClassDef;
39import org.jf.dexlib2.iface.Field;
40import org.jf.dexlib2.iface.value.EncodedValue;
41
42import javax.annotation.Nonnull;
43import javax.annotation.Nullable;
44import java.util.Set;
45
46public class DexBackedField extends BaseFieldReference implements Field {
47    @Nonnull public final DexBackedDexFile dexFile;
48    @Nonnull public final ClassDef classDef;
49
50    public final int accessFlags;
51    @Nullable public final EncodedValue initialValue;
52    public final int annotationSetOffset;
53
54    public final int fieldIndex;
55
56    private int fieldIdItemOffset;
57
58    public DexBackedField(@Nonnull DexReader reader,
59                          @Nonnull DexBackedClassDef classDef,
60                          int previousFieldIndex,
61                          @Nonnull StaticInitialValueIterator staticInitialValueIterator,
62                          @Nonnull AnnotationsDirectory.AnnotationIterator annotationIterator) {
63        this.dexFile = reader.dexBuf;
64        this.classDef = classDef;
65
66        // large values may be used for the index delta, which cause the cumulative index to overflow upon
67        // addition, effectively allowing out of order entries.
68        int fieldIndexDiff = reader.readLargeUleb128();
69        this.fieldIndex = fieldIndexDiff + previousFieldIndex;
70        this.accessFlags = reader.readSmallUleb128();
71
72        this.annotationSetOffset = annotationIterator.seekTo(fieldIndex);
73        this.initialValue = staticInitialValueIterator.getNextOrNull();
74    }
75
76    public DexBackedField(@Nonnull DexReader reader,
77                          @Nonnull DexBackedClassDef classDef,
78                          int previousFieldIndex,
79                          @Nonnull AnnotationsDirectory.AnnotationIterator annotationIterator) {
80        this.dexFile = reader.dexBuf;
81        this.classDef = classDef;
82
83        // large values may be used for the index delta, which cause the cumulative index to overflow upon
84        // addition, effectively allowing out of order entries.
85        int fieldIndexDiff = reader.readLargeUleb128();
86        this.fieldIndex = fieldIndexDiff + previousFieldIndex;
87        this.accessFlags = reader.readSmallUleb128();
88
89        this.annotationSetOffset = annotationIterator.seekTo(fieldIndex);
90        this.initialValue = null;
91    }
92
93    @Nonnull
94    @Override
95    public String getName() {
96        return dexFile.getString(dexFile.readSmallUint(getFieldIdItemOffset() + FieldIdItem.NAME_OFFSET));
97    }
98
99    @Nonnull
100    @Override
101    public String getType() {
102        return dexFile.getType(dexFile.readUshort(getFieldIdItemOffset() + FieldIdItem.TYPE_OFFSET));
103    }
104
105    @Nonnull @Override public String getDefiningClass() { return classDef.getType(); }
106    @Override public int getAccessFlags() { return accessFlags; }
107    @Nullable @Override public EncodedValue getInitialValue() { return initialValue; }
108
109    @Nonnull
110    @Override
111    public Set<? extends DexBackedAnnotation> getAnnotations() {
112        return AnnotationsDirectory.getAnnotations(dexFile, annotationSetOffset);
113    }
114
115    /**
116     * Skips the reader over the specified number of encoded_field structures
117     *
118     * @param reader The reader to skip
119     * @param count The number of encoded_field structures to skip over
120     */
121    public static void skipFields(@Nonnull DexReader reader, int count) {
122        for (int i=0; i<count; i++) {
123            reader.skipUleb128();
124            reader.skipUleb128();
125        }
126    }
127
128    private int getFieldIdItemOffset() {
129        if (fieldIdItemOffset == 0) {
130            fieldIdItemOffset = dexFile.getFieldIdItemOffset(fieldIndex);
131        }
132        return fieldIdItemOffset;
133    }
134}
135