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
17package com.android.dx.dex.code;
18
19import com.android.dx.rop.code.RegisterSpec;
20import com.android.dx.rop.code.RegisterSpecList;
21import com.android.dx.rop.code.RegisterSpecSet;
22import com.android.dx.rop.code.SourcePosition;
23
24/**
25 * Pseudo-instruction which is used to hold a snapshot of the
26 * state of local variable name mappings that exists immediately after
27 * the instance in an instruction array.
28 */
29public final class LocalSnapshot extends ZeroSizeInsn {
30    /** {@code non-null;} local state associated with this instance */
31    private final RegisterSpecSet locals;
32
33    /**
34     * Constructs an instance. The output address of this instance is initially
35     * unknown ({@code -1}).
36     *
37     * @param position {@code non-null;} source position
38     * @param locals {@code non-null;} associated local variable state
39     */
40    public LocalSnapshot(SourcePosition position, RegisterSpecSet locals) {
41        super(position);
42
43        if (locals == null) {
44            throw new NullPointerException("locals == null");
45        }
46
47        this.locals = locals;
48    }
49
50    /** {@inheritDoc} */
51    @Override
52    public DalvInsn withRegisterOffset(int delta) {
53        return new LocalSnapshot(getPosition(), locals.withOffset(delta));
54    }
55
56    /** {@inheritDoc} */
57    @Override
58    public DalvInsn withRegisters(RegisterSpecList registers) {
59        return new LocalSnapshot(getPosition(), locals);
60    }
61
62    /**
63     * Gets the local state associated with this instance.
64     *
65     * @return {@code non-null;} the state
66     */
67    public RegisterSpecSet getLocals() {
68        return locals;
69    }
70
71    /** {@inheritDoc} */
72    @Override
73    protected String argString() {
74        return locals.toString();
75    }
76
77    /** {@inheritDoc} */
78    @Override
79    protected String listingString0(boolean noteIndices) {
80        int sz = locals.size();
81        int max = locals.getMaxSize();
82        StringBuffer sb = new StringBuffer(100 + sz * 40);
83
84        sb.append("local-snapshot");
85
86        for (int i = 0; i < max; i++) {
87            RegisterSpec spec = locals.get(i);
88            if (spec != null) {
89                sb.append("\n  ");
90                sb.append(LocalStart.localString(spec));
91            }
92        }
93
94        return sb.toString();
95    }
96}
97