1/* 2 * Copyright (C) 2012 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.internal.util; 18 19import android.os.Handler; 20 21import java.io.PrintWriter; 22import java.io.StringWriter; 23 24/** 25 * Helper functions for dumping the state of system services. 26 */ 27public final class DumpUtils { 28 private DumpUtils() { 29 } 30 31 /** 32 * Helper for dumping state owned by a handler thread. 33 * 34 * Because the caller might be holding an important lock that the handler is 35 * trying to acquire, we use a short timeout to avoid deadlocks. The process 36 * is inelegant but this function is only used for debugging purposes. 37 */ 38 public static void dumpAsync(Handler handler, final Dump dump, PrintWriter pw, long timeout) { 39 final StringWriter sw = new StringWriter(); 40 if (handler.runWithScissors(new Runnable() { 41 @Override 42 public void run() { 43 PrintWriter lpw = new PrintWriter(sw); 44 dump.dump(lpw); 45 lpw.close(); 46 } 47 }, timeout)) { 48 pw.print(sw.toString()); 49 } else { 50 pw.println("... timed out"); 51 } 52 } 53 54 public interface Dump { 55 void dump(PrintWriter pw); 56 } 57} 58