Nicholas Orlowsky
3010f9326f
- allow creation of elm327 device without requiring unwrap() - added some extra documentation - add fuel_level obd-ii command - expose reset() functionality of device
90 lines
2.9 KiB
Rust
90 lines
2.9 KiB
Rust
//! Lower level OBD-II interfacing structures
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mod elm327;
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pub use elm327::Elm327;
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mod serial_comm;
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pub use serial_comm::{FTDIDevice, SerialPort};
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type Result<T> = std::result::Result<T, Error>;
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/// A lower-level API for using an OBD-II device
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pub trait Obd2BaseDevice: Obd2Reader {
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/// Reset the device and the OBD-II interface
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///
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/// First the device is reset, if it is stateful. Then the OBD-II interface is reinitialized,
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/// which resets the selected protocol on the device and rechecks the vehicle manufacturer if
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/// needed.
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fn reset(&mut self) -> Result<()>;
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/// Send an OBD-II command
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fn send_cmd(&mut self, data: &[u8]) -> Result<()>;
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/// Send an OBD-II command and get the reply
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///
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/// The reply is decoded into a String of mostly hex data. Depending on the format of the
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/// response, some other characters may be included like line numbers for multiline responses
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/// (of the format "0: AB CD ...").
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fn cmd(&mut self, cmd: &[u8]) -> Result<Option<String>> {
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self.send_cmd(cmd)?;
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self.get_response()
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.map(|o| o.and_then(|resp| String::from_utf8(resp).ok()))
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}
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}
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/// An API for reading OBD-II response data
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pub trait Obd2Reader {
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/// Try to get a single line of data from the device
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///
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/// The trailing newline is not included. This function will never return an empty line, it
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/// will retry until a line with data is found. If no data is available after a reasonable
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/// timeout, `Ok(None)` will be returned.
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fn get_line(&mut self) -> Result<Option<Vec<u8>>>;
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/// Get an entire OBD-II response
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///
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/// Empty vectors are allowed to be returned. This function should always be called after a
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/// command is sent, possibly after calling [get_line](Self::get_line) to read the first lines,
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/// so that any metadata sent by the device after the response from the vehicle can be dealt
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/// with.
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fn get_response(&mut self) -> Result<Option<Vec<u8>>>;
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}
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/// Error type for low-level ODB-II communication issues
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#[derive(thiserror::Error, Debug)]
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pub enum Error {
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/// An error with the underlying [FTDI device](ftdi::Device)
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#[error("FTDI error: `{0:?}`")]
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Ftdi(ftdi::Error),
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/// An error with the underlying [serialport device](serialport::SerialPort)
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#[error("Serialport error: `{0:?}`")]
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Serialport(serialport::Error),
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/// An I/O error in a low-level [std::io] stream operation
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#[error("IO error: `{0:?}`")]
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IO(std::io::Error),
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/// An OBD-II or interface device protocol error
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#[error("Communication error: `{0}`")]
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Communication(String),
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}
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impl From<ftdi::Error> for Error {
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fn from(e: ftdi::Error) -> Self {
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Error::Ftdi(e)
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}
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}
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impl From<serialport::Error> for Error {
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fn from(e: serialport::Error) -> Self {
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Error::Serialport(e)
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}
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}
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impl From<std::io::Error> for Error {
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fn from(e: std::io::Error) -> Self {
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Error::IO(e)
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}
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}
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