chore: add comments and remove unused code

hidrpc.go

@@ -109,6 +109,16 @@ func handleHidRPCKeyboardInput(message hidrpc.Message) (*usbgadget.KeysDownState
 }
 
 func reportHidRPC(params any, session *Session) {
+	if session == nil {
+		logger.Warn().Msg("session is nil, skipping reportHidRPC")
+		return
+	}
+
+	if !session.hidRPCAvailable || session.HidChannel == nil {
+		logger.Warn().Msg("HID RPC is not available, skipping reportHidRPC")
+		return
+	}
+
 	var (
 		message []byte
 		err     error

internal/usbgadget/hid_keyboard.go

@@ -146,6 +146,8 @@ func (u *UsbGadget) GetKeysDownState() KeysDownState {
 }
 
 func (u *UsbGadget) updateKeyDownState(state KeysDownState) {
+	u.log.Trace().Interface("old", u.keysDownState).Interface("new", state).Msg("acquiring keyboardStateLock for updateKeyDownState")
+
 	u.keyboardStateLock.Lock()
 	defer u.keyboardStateLock.Unlock()
 
@@ -242,7 +244,7 @@ func (u *UsbGadget) keyboardWriteHidFile(modifier byte, keys []byte) error {
 		return err
 	}
 
-	_, err := writeWithTimeout(u.keyboardHidFile, append([]byte{modifier, 0x00}, keys[:hidKeyBufferSize]...))
+	_, err := u.writeWithTimeout(u.keyboardHidFile, append([]byte{modifier, 0x00}, keys[:hidKeyBufferSize]...))
 	if err != nil {
 		u.logWithSuppression("keyboardWriteHidFile", 100, u.log, err, "failed to write to hidg0")
 		u.keyboardHidFile.Close()

internal/usbgadget/hid_mouse_absolute.go

@@ -74,7 +74,7 @@ func (u *UsbGadget) absMouseWriteHidFile(data []byte) error {
 		}
 	}
 
-	_, err := writeWithTimeout(u.absMouseHidFile, data)
+	_, err := u.writeWithTimeout(u.absMouseHidFile, data)
 	if err != nil {
 		u.logWithSuppression("absMouseWriteHidFile", 100, u.log, err, "failed to write to hidg1")
 		u.absMouseHidFile.Close()

internal/usbgadget/hid_mouse_relative.go

@@ -64,7 +64,7 @@ func (u *UsbGadget) relMouseWriteHidFile(data []byte) error {
 		}
 	}
 
-	_, err := writeWithTimeout(u.relMouseHidFile, data)
+	_, err := u.writeWithTimeout(u.relMouseHidFile, data)
 	if err != nil {
 		u.logWithSuppression("relMouseWriteHidFile", 100, u.log, err, "failed to write to hidg2")
 		u.relMouseHidFile.Close()

internal/usbgadget/utils.go

@@ -110,7 +110,7 @@ func compareFileContent(oldContent []byte, newContent []byte, looserMatch bool)
 	return false
 }
 
-func writeWithTimeout(file *os.File, data []byte) (n int, err error) {
+func (u *UsbGadget) writeWithTimeout(file *os.File, data []byte) (n int, err error) {
 	if err := file.SetWriteDeadline(time.Now().Add(hidWriteTimeout)); err != nil {
 		return -1, err
 	}
@@ -121,6 +121,14 @@ func writeWithTimeout(file *os.File, data []byte) (n int, err error) {
 	}
 
 	if errors.Is(err, os.ErrDeadlineExceeded) {
+		u.logWithSuppression(
+			fmt.Sprintf("writeWithTimeout_%s", file.Name()),
+			1000,
+			u.log,
+			err,
+			"write timed out: %s",
+			file.Name(),
+		)
 		err = nil
 	}
 

ui/src/components/WebRTCVideo.tsx

@@ -229,6 +229,7 @@ export default function WebRTCVideo() {
       if (rpcHidReady) {
         reportRelMouseEvent(dx, dy, buttons);
       } else {
+        // kept for backward compatibility
         send("relMouseReport", { dx, dy, buttons });
       }
       setMouseMove({ x, y, buttons });
@@ -260,6 +261,7 @@ export default function WebRTCVideo() {
       if (rpcHidReady) {
         reportAbsMouseEvent(x, y, buttons);
       } else {
+        // kept for backward compatibility
         send("absMouseReport", { x, y, buttons });
       }
       // We set that for the debug info bar

ui/src/hooks/useKeyboard.ts

@@ -51,26 +51,13 @@ export default function useKeyboard() {
       if (rpcHidReady) {
         console.debug("Sending keyboard report via HidRPC");
         reportKeyboardEvent(state.keys, state.modifier);
+        setkeyPressReportApiAvailable(true);
         return;
       }
 
       send("keyboardReport", { keys: state.keys, modifier: state.modifier }, (resp: JsonRpcResponse) => {
         if ("error" in resp) {
           console.error(`Failed to send keyboard report ${state}`, resp.error);
-        } else {
-          // If the device supports keyPressReport API, it will (also) return the keysDownState when we send
-          // the keyboardReport
-          const keysDownState = resp.result as KeysDownState;
-
-          if (keysDownState) {
-            setKeysDownState(keysDownState); // treat the response as the canonical state
-            setkeyPressReportApiAvailable(true); // if they returned a keysDownState, we ALSO know they also support keyPressReport
-          } else {
-            // older devices versions do not return the keyDownState
-            // so we just pretend they accepted what we sent
-            setKeysDownState(state);
-            setkeyPressReportApiAvailable(false); // we ALSO know they do not support keyPressReport
-          }
         }
       });
     },
@@ -79,7 +66,6 @@ export default function useKeyboard() {
       rpcHidReady,
       send,
       reportKeyboardEvent,
-      setKeysDownState,
       setkeyPressReportApiAvailable,
     ],
   );
@@ -92,41 +78,14 @@ export default function useKeyboard() {
   // in client/browser-side code using simulateDeviceSideKeyHandlingForLegacyDevices.
   const sendKeypressEvent = useCallback(
     async (key: number, press: boolean) => {
-      if (rpcDataChannel?.readyState !== "open" && !rpcHidReady) return;
-
       console.debug(`Send keypressEvent key: ${key}, press: ${press}`);
 
-      if (rpcHidReady) {
-        console.debug("Sending keypress event via HidRPC");
-        reportKeypressEvent(key, press);
-        return;
-      }
+      if (!rpcHidReady) return;
 
-      send("keypressReport", { key, press }, (resp: JsonRpcResponse) => {
-        if ("error" in resp) {
-          // -32601 means the method is not supported because the device is running an older version
-          if (resp.error.code === -32601) {
-            console.error("Legacy device does not support keypressReport API, switching to local key down state handling", resp.error);
-            setkeyPressReportApiAvailable(false);
-          } else {
-            console.error(`Failed to send key ${key} press: ${press}`, resp.error);
-          }
-        } else {
-          const keysDownState = resp.result as KeysDownState;
-
-          if (keysDownState) {
-            setKeysDownState(keysDownState);
-            // we don't need to set keyPressReportApiAvailable here, because it's already true or we never landed here
-          }
-        }
-      });
+      reportKeypressEvent(key, press);
     },
     [
-      rpcDataChannel?.readyState,
       rpcHidReady,
-      send,
-      setkeyPressReportApiAvailable,
-      setKeysDownState,
       reportKeypressEvent,
     ],
   );