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 
RemoteEventTrace(WindowManagerService service, FileDescriptor fd)37     RemoteEventTrace(WindowManagerService service, FileDescriptor fd) {
38         mService = service;
39         mOut = new DataOutputStream(new FileOutputStream(fd, false));
40     }
41 
openSurfaceTransaction()42     void openSurfaceTransaction() {
43         try {
44             mOut.writeUTF("OpenTransaction");
45             writeSigil();
46         } catch (Exception e) {
47             logException(e);
48             mService.disableSurfaceTrace();
49         }
50     }
51 
closeSurfaceTransaction()52     void closeSurfaceTransaction() {
53         try {
54             mOut.writeUTF("CloseTransaction");
55             writeSigil();
56         } catch (Exception e) {
57             logException(e);
58             mService.disableSurfaceTrace();
59         }
60     }
61 
writeSigil()62     private void writeSigil() throws Exception {
63         mOut.write(RemoteEventTrace.sigil, 0, 4);
64     }
65 
logException(Exception e)66     static void logException(Exception e) {
67         Slog.i(TAG, "Exception writing to SurfaceTrace (client vanished?): " + e.toString());
68     }
69 }
70