Disable default stdout/stderr for Xiaomi devices

Xiaomi device ROMs print internal errors using e.printStackTRace(),
flooding the console with irrelevant errors.

To get rid of them, on Xiaomi devices, trash the messages printed to the
console by direct calls to System.out and System.err.

Refs #994 <https://github.com/Genymobile/scrcpy/issues/994>
Refs #4213 <https://github.com/Genymobile/scrcpy/pull/4213>

app/scrcpy.1

@@ -45,15 +45,15 @@ Set a list of comma-separated key:type=value options for the device audio encode
 
 The possible values for 'type' are 'int' (default), 'long', 'float' and 'string'.
 
-The list of possible codec options is available in the Android documentation
-.UR https://d.android.com/reference/android/media/MediaFormat
-.UE .
+The list of possible codec options is available in the Android documentation:
+
+<https://d.android.com/reference/android/media/MediaFormat>
 
 .TP
 .BI "\-\-audio\-encoder " name
 Use a specific MediaCodec audio encoder (depending on the codec provided by \fB\-\-audio\-codec\fR).
 
-The available encoders can be listed by \-\-list\-encoders.
+The available encoders can be listed by \fB\-\-list\-encoders\fR.
 
 .TP
 .BI "\-\-audio\-source " source
@@ -79,19 +79,19 @@ Default is 8M (8000000).
 .BI "\-\-camera\-ar " ar
 Select the camera size by its aspect ratio (+/- 10%).
 
-Possible values are "sensor" (use the camera sensor aspect ratio), "<num>:<den>" (e.g. "4:3") and "<value>" (e.g. "1.6").
+Possible values are "sensor" (use the camera sensor aspect ratio), "\fInum\fR:\fIden\fR" (e.g. "4:3") and "\fIvalue\fR" (e.g. "1.6").
 
 .TP
 .B \-\-camera\-high\-speed
 Enable high-speed camera capture mode.
 
-This mode is restricted to specific resolutions and frame rates, listed by --list-camera-sizes.
+This mode is restricted to specific resolutions and frame rates, listed by \fB\-\-list\-camera\-sizes\fR.
 
 .TP
 .BI "\-\-camera\-id " id
 Specify the device camera id to mirror.
 
-The available camera ids can be listed by \-\-list\-cameras.
+The available camera ids can be listed by \fB\-\-list\-cameras\fR.
 
 .TP
 .BI "\-\-camera\-facing " facing
@@ -131,7 +131,7 @@ Disable screensaver while scrcpy is running.
 .BI "\-\-display\-id " id
 Specify the device display id to mirror.
 
-The available display ids can be listed by \-\-list\-displays.
+The available display ids can be listed by \fB\-\-list\-displays\fR.
 
 Default is 0.
 
@@ -189,9 +189,11 @@ Inject computer clipboard text as a sequence of key events on Ctrl+v (like MOD+S
 
 This is a workaround for some devices not behaving as expected when setting the device clipboard programmatically.
 
+.TP
 .B \-\-list\-camera\-sizes
 List the valid camera capture sizes.
 
+.TP
 .B \-\-list\-cameras
 List cameras available on the device.
 
@@ -239,7 +241,7 @@ Disable device control (mirror the device in read\-only).
 
 .TP
 .B \-N, \-\-no\-playback
-Disable video and audio playback on the computer (equivalent to --no-video-playback --no-audio-playback).
+Disable video and audio playback on the computer (equivalent to \fB\-\-no\-video\-playback \-\-no\-audio\-playback\fR).
 
 .TP
 .B \-\-no\-audio
@@ -361,8 +363,7 @@ Request SDL to use the given render driver (this is just a hint).
 
 Supported names are currently "direct3d", "opengl", "opengles2", "opengles", "metal" and "software".
 
-.UR https://wiki.libsdl.org/SDL_HINT_RENDER_DRIVER
-.UE
+<https://wiki.libsdl.org/SDL_HINT_RENDER_DRIVER>
 
 .TP
 .B \-\-require\-audio
@@ -410,13 +411,13 @@ Set the maximum mirroring time, in seconds.
 
 .TP
 .BI "\-\-tunnel\-host " ip
-Set the IP address of the adb tunnel to reach the scrcpy server. This option automatically enables --force-adb-forward.
+Set the IP address of the adb tunnel to reach the scrcpy server. This option automatically enables \fB\-\-force\-adb\-forward\fR.
 
 Default is localhost.
 
 .TP
 .BI "\-\-tunnel\-port " port
-Set the TCP port of the adb tunnel to reach the scrcpy server. This option automatically enables --force-adb-forward.
+Set the TCP port of the adb tunnel to reach the scrcpy server. This option automatically enables \fB\-\-force\-adb\-forward\fR.
 
 Default is 0 (not forced): the local port used for establishing the tunnel will be used.
 
@@ -456,15 +457,15 @@ Set a list of comma-separated key:type=value options for the device video encode
 
 The possible values for 'type' are 'int' (default), 'long', 'float' and 'string'.
 
-The list of possible codec options is available in the Android documentation
-.UR https://d.android.com/reference/android/media/MediaFormat
-.UE .
+The list of possible codec options is available in the Android documentation:
+
+<https://d.android.com/reference/android/media/MediaFormat>
 
 .TP
 .BI "\-\-video\-encoder " name
 Use a specific MediaCodec video encoder (depending on the codec provided by \fB\-\-video\-codec\fR).
 
-The available encoders can be listed by \-\-list\-encoders.
+The available encoders can be listed by \fB\-\-list\-encoders\fR.
 
 .TP
 .BI "\-\-video\-source " source
@@ -634,7 +635,7 @@ Path to adb.
 
 .TP
 .B ANDROID_SERIAL
-Device serial to use if no selector (-s, -d, -e or --tcpip=<addr>) is specified.
+Device serial to use if no selector (\fB-s\fR, \fB-d\fR, \fB-e\fR or \fB\-\-tcpip=\fIaddr\fR) is specified.
 
 .TP
 .B SCRCPY_ICON_PATH
@@ -657,23 +658,14 @@ for the Debian Project (and may be used by others).
 
 
 .SH "REPORTING BUGS"
-Report bugs to
-.UR https://github.com/Genymobile/scrcpy/issues
-.UE .
+Report bugs to <https://github.com/Genymobile/scrcpy/issues>.
 
 .SH COPYRIGHT
-Copyright \(co 2018 Genymobile
-.UR https://www.genymobile.com
-Genymobile
-.UE
+Copyright \(co 2018 Genymobile <https://www.genymobile.com>
 
-Copyright \(co 2018\-2023
-.MT rom@rom1v.com
-Romain Vimont
-.ME
+Copyright \(co 2018\-2023 Romain Vimont <rom@rom1v.com>
 
 Licensed under the Apache License, Version 2.0.
 
 .SH WWW
-.UR https://github.com/Genymobile/scrcpy
-.UE
+<https://github.com/Genymobile/scrcpy>

server/src/main/java/com/genymobile/scrcpy/Ln.java

@@ -8,6 +8,11 @@ import android.util.Log;
  */
 public final class Ln {
 
+    public interface ConsolePrinter {
+        void printOut(String message);
+        void printErr(String message, Throwable throwable);
+    }
+
     private static final String TAG = "scrcpy";
     private static final String PREFIX = "[server] ";
 
@@ -15,12 +20,17 @@ public final class Ln {
         VERBOSE, DEBUG, INFO, WARN, ERROR
     }
 
+    private static ConsolePrinter consolePrinter = new DefaultConsolePrinter();
     private static Level threshold = Level.INFO;
 
     private Ln() {
         // not instantiable
     }
 
+    public static void setConsolePrinter(ConsolePrinter consolePrinter) {
+        Ln.consolePrinter = consolePrinter;
+    }
+
     /**
      * Initialize the log level.
      * <p>
@@ -39,31 +49,28 @@ public final class Ln {
     public static void v(String message) {
         if (isEnabled(Level.VERBOSE)) {
             Log.v(TAG, message);
-            System.out.print(PREFIX + "VERBOSE: " + message + '\n');
+            consolePrinter.printOut(PREFIX + "VERBOSE: " + message + '\n');
         }
     }
 
     public static void d(String message) {
         if (isEnabled(Level.DEBUG)) {
             Log.d(TAG, message);
-            System.out.print(PREFIX + "DEBUG: " + message + '\n');
+            consolePrinter.printOut(PREFIX + "DEBUG: " + message + '\n');
         }
     }
 
     public static void i(String message) {
         if (isEnabled(Level.INFO)) {
             Log.i(TAG, message);
-            System.out.print(PREFIX + "INFO: " + message + '\n');
+            consolePrinter.printOut(PREFIX + "INFO: " + message + '\n');
         }
     }
 
     public static void w(String message, Throwable throwable) {
         if (isEnabled(Level.WARN)) {
             Log.w(TAG, message, throwable);
-            System.err.print(PREFIX + "WARN: " + message + '\n');
-            if (throwable != null) {
-                throwable.printStackTrace();
-            }
+            consolePrinter.printErr(PREFIX + "WARN: " + message + '\n', throwable);
         }
     }
 
@@ -74,14 +81,26 @@ public final class Ln {
     public static void e(String message, Throwable throwable) {
         if (isEnabled(Level.ERROR)) {
             Log.e(TAG, message, throwable);
-            System.err.print(PREFIX + "ERROR: " + message + "\n");
-            if (throwable != null) {
-                throwable.printStackTrace();
-            }
+            consolePrinter.printErr(PREFIX + "ERROR: " + message + '\n', throwable);
         }
     }
 
     public static void e(String message) {
         e(message, null);
     }
+
+    public static class DefaultConsolePrinter implements ConsolePrinter {
+        @Override
+        public void printOut(String message) {
+            System.out.print(message);
+        }
+
+        @Override
+        public void printErr(String message, Throwable throwable) {
+            System.err.print(message);
+            if (throwable != null) {
+                throwable.printStackTrace();
+            }
+        }
+    }
 }

server/src/main/java/com/genymobile/scrcpy/Server.java

@@ -87,8 +87,6 @@ public final class Server {
     }
 
     private static void scrcpy(Options options) throws IOException, ConfigurationException {
-        Ln.i("Device: [" + Build.MANUFACTURER + "] " + Build.BRAND + " " + Build.MODEL + " (Android " + Build.VERSION.RELEASE + ")");
-
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.S && options.getVideoSource() == VideoSource.CAMERA) {
             Ln.e("Camera mirroring is not supported before Android 12");
             throw new ConfigurationException("Camera mirroring is not supported");
@@ -208,6 +206,8 @@ public final class Server {
 
         Ln.initLogLevel(options.getLogLevel());
 
+        Ln.i("Device: [" + Build.MANUFACTURER + "] " + Build.BRAND + " " + Build.MODEL + " (Android " + Build.VERSION.RELEASE + ")");
+
         if (options.getList()) {
             if (options.getCleanup()) {
                 CleanUp.unlinkSelf();

server/src/main/java/com/genymobile/scrcpy/Workarounds.java

@@ -14,6 +14,12 @@ import android.os.Build;
 import android.os.Looper;
 import android.os.Parcel;
 
+import java.io.FileDescriptor;
+import java.io.FileOutputStream;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.io.PrintWriter;
+import java.io.StringWriter;
 import java.lang.ref.WeakReference;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
@@ -55,6 +61,12 @@ public final class Workarounds {
             mustFillAppInfo = true;
             mustFillBaseContext = true;
             mustFillAppContext = true;
+        } else if (Build.MANUFACTURER.equalsIgnoreCase("xiaomi")) {
+            // Trash the messages printed to the console by direct calls to System.out and System.err.
+            // Xiaomi device ROMs may print internal errors using e.printStackTrace(), flooding the console with irrelevant errors.
+            ExclusiveConsolePrinter exclusiveConsolePrinter = new ExclusiveConsolePrinter();
+            exclusiveConsolePrinter.installNullSystemStreams();
+            Ln.setConsolePrinter(new ExclusiveConsolePrinter());
         }
 
         if (audio && Build.VERSION.SDK_INT == Build.VERSION_CODES.R) {
@@ -306,4 +318,48 @@ public final class Workarounds {
             throw new RuntimeException("Cannot create AudioRecord");
         }
     }
+
+    static class ExclusiveConsolePrinter implements Ln.ConsolePrinter {
+
+        static class NullOutputStream extends OutputStream {
+            @Override
+            public void write(byte[] b) {
+                // ignore
+            }
+
+            @Override
+            public void write(byte[] b, int off, int len) {
+                // ignore
+            }
+
+            @Override
+            public void write(int b) {
+                // ignore
+            }
+        }
+
+        private final PrintStream realOut = new PrintStream(new FileOutputStream(FileDescriptor.out));
+        private final PrintStream realErr = new PrintStream(new FileOutputStream(FileDescriptor.err));
+
+        void installNullSystemStreams() {
+            PrintStream nullStream = new PrintStream(new NullOutputStream());
+            System.setOut(nullStream);
+            System.setErr(nullStream);
+        }
+
+        @Override
+        public void printOut(String message) {
+            realOut.print(message);
+        }
+
+        @Override
+        public void printErr(String message, Throwable throwable) {
+            realErr.print(message);
+            if (throwable != null) {
+                StringWriter errors = new StringWriter();
+                throwable.printStackTrace(new PrintWriter(errors));
+                realErr.print(errors);
+            }
+        }
+    }
 }