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      1 /*
      2  * Copyright (C) 2016 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.server.wm;
     18 
     19 import java.io.FileDescriptor;
     20 import java.io.FileOutputStream;
     21 import java.io.DataOutputStream;
     22 
     23 import android.util.Slog;
     24 import android.os.Debug;
     25 
     26 // Counterpart to remote surface trace for events which are not tied to a particular surface.
     27 class RemoteEventTrace {
     28     private static final String TAG = "RemoteEventTrace";
     29 
     30     // We terminate all our messages with a recognizable marker, to avoid issues
     31     // with partial reads (which ADB makes impossible to avoid).
     32     static final byte[] sigil = {(byte)0xfc, (byte)0xfc, (byte)0xfc, (byte)0xfc};
     33 
     34     private final WindowManagerService mService;
     35     private final DataOutputStream mOut;
     36 
     37     RemoteEventTrace(WindowManagerService service, FileDescriptor fd) {
     38         mService = service;
     39         mOut = new DataOutputStream(new FileOutputStream(fd, false));
     40     }
     41 
     42     void openSurfaceTransaction() {
     43         try {
     44             mOut.writeUTF("OpenTransaction");
     45             writeSigil();
     46         } catch (Exception e) {
     47             logException(e);
     48             mService.disableSurfaceTrace();
     49         }
     50     }
     51 
     52     void closeSurfaceTransaction() {
     53         try {
     54             mOut.writeUTF("CloseTransaction");
     55             writeSigil();
     56         } catch (Exception e) {
     57             logException(e);
     58             mService.disableSurfaceTrace();
     59         }
     60     }
     61 
     62     private void writeSigil() throws Exception {
     63         mOut.write(RemoteEventTrace.sigil, 0, 4);
     64     }
     65 
     66     static void logException(Exception e) {
     67         Slog.i(TAG, "Exception writing to SurfaceTrace (client vanished?): " + e.toString());
     68     }
     69 }
     70