Add shortcuts to switch the camera torch

MOD+l turns on the camera torch, MOD+Shift+l turns it off.

TODO ref 6243

Co-authored-by: Tommie <teh420@gmail.com>

server/src/main/java/com/genymobile/scrcpy/control/ControlMessage.java

@@ -25,6 +25,7 @@ public final class ControlMessage {
     public static final int TYPE_OPEN_HARD_KEYBOARD_SETTINGS = 15;
     public static final int TYPE_START_APP = 16;
     public static final int TYPE_RESET_VIDEO = 17;
+    public static final int TYPE_CAMERA_SET_TORCH = 18;
 
     public static final long SEQUENCE_INVALID = 0;
 
@@ -166,6 +167,13 @@ public final class ControlMessage {
         return msg;
     }
 
+    public static ControlMessage createCameraSetTorch(boolean on) {
+        ControlMessage msg = new ControlMessage();
+        msg.type = TYPE_CAMERA_SET_TORCH;
+        msg.on = on;
+        return msg;
+    }
+
     public int getType() {
         return type;
     }

server/src/main/java/com/genymobile/scrcpy/control/ControlMessageReader.java

@@ -56,6 +56,8 @@ public class ControlMessageReader {
                 return parseUhidDestroy();
             case ControlMessage.TYPE_START_APP:
                 return parseStartApp();
+            case ControlMessage.TYPE_CAMERA_SET_TORCH:
+                return parseCameraSetTorch();
             default:
                 throw new ControlProtocolException("Unknown event type: " + type);
         }
@@ -166,6 +168,11 @@ public class ControlMessageReader {
         return ControlMessage.createStartApp(name);
     }
 
+    private ControlMessage parseCameraSetTorch() throws IOException {
+        boolean on = dis.readBoolean();
+        return ControlMessage.createCameraSetTorch(on);
+    }
+
     private Position parsePosition() throws IOException {
         int x = dis.readInt();
         int y = dis.readInt();

server/src/main/java/com/genymobile/scrcpy/control/Controller.java

@@ -12,6 +12,7 @@ import com.genymobile.scrcpy.device.Position;
 import com.genymobile.scrcpy.device.Size;
 import com.genymobile.scrcpy.util.Ln;
 import com.genymobile.scrcpy.util.LogUtils;
+import com.genymobile.scrcpy.video.CameraCapture;
 import com.genymobile.scrcpy.video.SurfaceCapture;
 import com.genymobile.scrcpy.video.VideoSource;
 import com.genymobile.scrcpy.video.VirtualDisplayListener;
@@ -99,7 +100,7 @@ public class Controller implements AsyncProcessor, VirtualDisplayListener {
 
     private boolean keepDisplayPowerOff;
 
-    // Used for resetting video encoding on RESET_VIDEO message
+    // Used for resetting video encoding on RESET_VIDEO message or for sending camera controls
     private SurfaceCapture surfaceCapture;
 
     public Controller(ControlChannel controlChannel, CleanUp cleanUp, Options options) {
@@ -365,6 +366,16 @@ public class Controller implements AsyncProcessor, VirtualDisplayListener {
                 default:
                     // fall through
             }
+        } else {
+            switch (type) {
+                case ControlMessage.TYPE_CAMERA_SET_TORCH:
+                    assert surfaceCapture instanceof CameraCapture;
+                    CameraCapture cameraCapture = (CameraCapture) surfaceCapture;
+                    cameraCapture.setTorchEnabled(msg.getOn());
+                    return true;
+                default:
+                    // fall through
+            }
         }
 
         throw new AssertionError("Unexpected message type: " + type);

server/src/main/java/com/genymobile/scrcpy/video/CameraCapture.java

@@ -80,8 +80,10 @@ public class CameraCapture extends SurfaceCapture {
 
     private final AtomicBoolean disconnected = new AtomicBoolean();
 
-    // Must be accessed only from the camera thread
+    // The following fields must be accessed only from the camera thread
     private boolean started;
+    private CaptureRequest.Builder requestBuilder;
+    private CameraCaptureSession currentSession;
 
     public CameraCapture(Options options) {
         this.explicitCameraId = options.getCameraId();
@@ -287,7 +289,7 @@ public class CameraCapture extends SurfaceCapture {
                 }
 
                 try {
-                    CaptureRequest.Builder requestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_RECORD);
+                    requestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_RECORD);
                     requestBuilder.addTarget(captureSurface);
 
                     if (fps > 0) {
@@ -299,6 +301,7 @@ public class CameraCapture extends SurfaceCapture {
 
                     CaptureRequest request = requestBuilder.build();
                     setRepeatingRequest(session, request);
+                    currentSession = session;
                 } catch (CameraAccessException e) {
                     Ln.e("Camera error", e);
                     invalidate();
@@ -324,6 +327,8 @@ public class CameraCapture extends SurfaceCapture {
     public void stop() {
         cameraHandler.post(() -> {
             assertCameraThread();
+            currentSession = null;
+            requestBuilder = null;
             started = false;
         });
 
@@ -434,6 +439,21 @@ public class CameraCapture extends SurfaceCapture {
         return disconnected.get();
     }
 
+    public void setTorchEnabled(boolean enabled) {
+        cameraHandler.post(() -> {
+            assertCameraThread();
+            if (currentSession != null && requestBuilder != null) {
+                try {
+                    requestBuilder.set(CaptureRequest.FLASH_MODE, enabled ? CaptureRequest.FLASH_MODE_TORCH : CaptureRequest.FLASH_MODE_OFF);
+                    CaptureRequest request = requestBuilder.build();
+                    setRepeatingRequest(currentSession, request);
+                } catch (CameraAccessException e) {
+                    Ln.e("Camera error", e);
+                }
+            }
+        });
+    }
+
     private void assertCameraThread() {
         assert Thread.currentThread() == cameraThread;
     }

server/src/test/java/com/genymobile/scrcpy/control/ControlMessageReaderTest.java

@@ -422,6 +422,24 @@ public class ControlMessageReaderTest {
         Assert.assertEquals(-1, bis.read()); // EOS
     }
 
+    @Test
+    public void testParseCameraSetTorch() throws IOException {
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        DataOutputStream dos = new DataOutputStream(bos);
+        dos.writeByte(ControlMessage.TYPE_CAMERA_SET_TORCH);
+        dos.writeBoolean(true);
+        byte[] packet = bos.toByteArray();
+
+        ByteArrayInputStream bis = new ByteArrayInputStream(packet);
+        ControlMessageReader reader = new ControlMessageReader(bis);
+
+        ControlMessage event = reader.read();
+        Assert.assertEquals(ControlMessage.TYPE_CAMERA_SET_TORCH, event.getType());
+        Assert.assertTrue(event.getOn());
+
+        Assert.assertEquals(-1, bis.read()); // EOS
+    }
+
     @Test
     public void testMultiEvents() throws IOException {
         ByteArrayOutputStream bos = new ByteArrayOutputStream();