1/*
2 * Copyright (C) 2010 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 dalvik.system.profiler;
18
19import dalvik.system.VMStack;
20import java.util.Arrays;
21
22class DalvikThreadSampler implements ThreadSampler {
23
24    private int depth;
25
26    /**
27     * Reusable storage for sampling sized for the specified depth.
28     */
29    private StackTraceElement[][] mutableStackTraceElements;
30
31    @Override public void setDepth(int depth) {
32        this.depth = depth;
33        this.mutableStackTraceElements = new StackTraceElement[depth+1][];
34        for (int i = 1; i < mutableStackTraceElements.length; i++) {
35            this.mutableStackTraceElements[i] = new StackTraceElement[i];
36        }
37    }
38
39    @Override public StackTraceElement[] getStackTrace(Thread thread) {
40        int count = VMStack.fillStackTraceElements(thread, mutableStackTraceElements[depth]);
41        if (count == 0) {
42            return null;
43        }
44        if (count < depth) {
45            System.arraycopy(mutableStackTraceElements[depth], 0,
46                             mutableStackTraceElements[count], 0,
47                             count);
48        }
49        return mutableStackTraceElements[count];
50    }
51}
52