nreal: switch to hidapi

Cargo.toml

@@ -15,11 +15,12 @@ license = "MIT"
 [features]
 default = ["mad_gaze", "rokid", "nreal"]
 rokid = ["rusb"]
-nreal = ["rusb", "tinyjson"]
+nreal = ["hidapi", "tinyjson"]
 mad_gaze = ["serialport"]
 
 [dependencies]
 byteorder = "1.4"
+hidapi = { version = "2.2.2", optional = true }
 rusb = { version = "0.9.1", optional = true }
 serialport = { version = "4.2", optional = true }
 tinyjson = { version = "2.5.1", optional = true }

src/lib.rs

@@ -46,11 +46,18 @@ pub enum Error {
     /// An rusb error happened. See [`rusb::Error`] for specifics
     #[cfg(feature = "rusb")]
     UsbError(rusb::Error),
+    /// A hidapi error happened. See [`hidapi::HidError`] for specifics
+    #[cfg(feature = "rusb")]
+    HidError(hidapi::HidError),
     /// A serialport error happened. See [`serialport::Error`] for specifics
     #[cfg(feature = "serialport")]
     SerialPortError(serialport::Error),
     /// No glasses were found.
     NotFound,
+    /// Packet sending or reception timed out. Note that this is not the only
+    /// timeout error that is sent (e.g. UsbError can contain a timeout), and
+    /// also this is usually a fatal one.
+    PacketTimeout,
     /// The glasses (or one of its devices) were disconnected
     Disconnected(&'static str),
     /// Other fatal error, usually a problem with the library itself, or
@@ -156,6 +163,13 @@ impl From<rusb::Error> for Error {
     }
 }
 
+#[cfg(feature = "hidapi")]
+impl From<hidapi::HidError> for Error {
+    fn from(e: hidapi::HidError) -> Self {
+        Error::HidError(e)
+    }
+}
+
 #[cfg(feature = "serialport")]
 impl From<serialport::Error> for Error {
     fn from(e: serialport::Error) -> Self {