DexBackedTryBlock.java revision be799799ff8bbc5d86f8cfdc850947ab4f41695f 
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.DexFile;
35import org.jf.dexlib2.DexFileReader;
36import org.jf.dexlib2.iface.ExceptionHandler;
37import org.jf.dexlib2.iface.TryBlock;
38import org.jf.dexlib2.dexbacked.util.VariableSizeList;
39
40import javax.annotation.Nonnull;
41import java.util.List;
42
43public class DexBackedTryBlock implements TryBlock {
44    public final DexFile dexFile;
45
46    public final int startIndex;
47    public final int instructionCount;
48
49    private final int exceptionHandlersOffset;
50
51    public DexBackedTryBlock(DexFile dexFile,
52                             int offset,
53                             int handlersStartOffset) {
54        this.dexFile = dexFile;
55        this.startIndex = dexFile.readSmallUint(offset);
56        this.instructionCount = dexFile.readUshort(offset+4);
57        this.exceptionHandlersOffset = handlersStartOffset + dexFile.readUshort(6);
58    }
59
60    @Override public int getStartIndex() { return startIndex; }
61    @Override public int getInstructionCount() { return instructionCount; }
62
63    @Nonnull
64    @Override
65    public List<? extends ExceptionHandler> getExceptionHandlers() {
66        DexFileReader reader = dexFile.readerAt(exceptionHandlersOffset);
67        final int encodedSize = reader.readSleb128();
68
69        if (encodedSize > 0) {
70            //no catch-all
71            return new VariableSizeList<ExceptionHandler>(dexFile, reader.getOffset()) {
72                @Override
73                protected ExceptionHandler readItem(DexFileReader dexFileReader, int index) {
74                    return new DexBackedExceptionHandler(dexFileReader);
75                }
76                @Override public int size() { return encodedSize; }
77            };
78        } else {
79            //with catch-all
80            final int sizeWithCatchAll = (-1 * encodedSize) + 1;
81            return new VariableSizeList<ExceptionHandler>(dexFile, reader.getOffset()) {
82                @Override
83                protected ExceptionHandler readItem(DexFileReader dexFileReader, int index) {
84                    if (index == sizeWithCatchAll-1) {
85                        return new DexBackedCatchAllExceptionHandler(dexFileReader);
86                    } else {
87                        return new DexBackedExceptionHandler(dexFileReader);
88                    }
89                }
90                @Override public int size() { return sizeWithCatchAll; }
91            };
92        }
93    }
94}
95