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      1 /*
      2  * Copyright (C) 2008 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 
     17 package com.android.internal.os;
     18 
     19 import android.os.IBinder;
     20 import android.os.SystemClock;
     21 import android.util.EventLog;
     22 
     23 import java.lang.ref.WeakReference;
     24 import java.util.ArrayList;
     25 
     26 /**
     27  * Private and debugging Binder APIs.
     28  *
     29  * @see IBinder
     30  */
     31 public class BinderInternal {
     32     static WeakReference<GcWatcher> sGcWatcher
     33             = new WeakReference<GcWatcher>(new GcWatcher());
     34     static ArrayList<Runnable> sGcWatchers = new ArrayList<>();
     35     static Runnable[] sTmpWatchers = new Runnable[1];
     36     static long sLastGcTime;
     37 
     38     static final class GcWatcher {
     39         @Override
     40         protected void finalize() throws Throwable {
     41             handleGc();
     42             sLastGcTime = SystemClock.uptimeMillis();
     43             synchronized (sGcWatchers) {
     44                 sTmpWatchers = sGcWatchers.toArray(sTmpWatchers);
     45             }
     46             for (int i=0; i<sTmpWatchers.length; i++) {
     47                 if (sTmpWatchers[i] != null) {
     48                     sTmpWatchers[i].run();
     49                 }
     50             }
     51             sGcWatcher = new WeakReference<GcWatcher>(new GcWatcher());
     52         }
     53     }
     54 
     55     public static void addGcWatcher(Runnable watcher) {
     56         synchronized (sGcWatchers) {
     57             sGcWatchers.add(watcher);
     58         }
     59     }
     60 
     61     /**
     62      * Add the calling thread to the IPC thread pool.  This function does
     63      * not return until the current process is exiting.
     64      */
     65     public static final native void joinThreadPool();
     66 
     67     /**
     68      * Return the system time (as reported by {@link SystemClock#uptimeMillis
     69      * SystemClock.uptimeMillis()}) that the last garbage collection occurred
     70      * in this process.  This is not for general application use, and the
     71      * meaning of "when a garbage collection occurred" will change as the
     72      * garbage collector evolves.
     73      *
     74      * @return Returns the time as per {@link SystemClock#uptimeMillis
     75      * SystemClock.uptimeMillis()} of the last garbage collection.
     76      */
     77     public static long getLastGcTime() {
     78         return sLastGcTime;
     79     }
     80 
     81     /**
     82      * Return the global "context object" of the system.  This is usually
     83      * an implementation of IServiceManager, which you can use to find
     84      * other services.
     85      */
     86     public static final native IBinder getContextObject();
     87 
     88     /**
     89      * Special for system process to not allow incoming calls to run at
     90      * background scheduling priority.
     91      * @hide
     92      */
     93     public static final native void disableBackgroundScheduling(boolean disable);
     94 
     95     static native final void handleGc();
     96 
     97     public static void forceGc(String reason) {
     98         EventLog.writeEvent(2741, reason);
     99         Runtime.getRuntime().gc();
    100     }
    101 
    102     static void forceBinderGc() {
    103         forceGc("Binder");
    104     }
    105 }
    106