Reorganize commands module

src/commands/implementation.rs

@@ -0,0 +1,83 @@
+use crate::{commands::Obd2DataRetrieval, Error, Obd2Device, Result};
+
+use super::{Dtc, DtcsInfo};
+
+impl<T: Obd2Device> Obd2DataRetrieval for T {
+    fn get_vin(&mut self) -> Result<String> {
+        let mut result = self.obd_command(0x09, 0x02)?.pop().unwrap();
+        result.remove(0); // do not know what this byte is
+        Ok(String::from_utf8(result)?)
+    }
+
+    fn get_dtc_info(&mut self) -> Result<Vec<DtcsInfo>> {
+        let result = self.obd_command(0x01, 0x01)?;
+
+        result
+            .iter()
+            .map(|response| {
+                if response.len() == 4 {
+                    Ok(DtcsInfo {
+                        malfunction_indicator_light: (response[0] & 0x80) == 0x80,
+                        dtc_count: response[0] & 0x7f,
+                        common_test_availability: ((response[1] & 0xf0) >> 1)
+                            | (response[1] & 0x07),
+                        is_compression_engine: (response[1] & 0x08) == 0x08,
+                        specific_test_availability: ((response[3] as u16) << 8)
+                            | (response[2] as u16),
+                    })
+                } else {
+                    Err(Error::Other(format!(
+                        "get_dtc_info: expected length 4, got {}",
+                        response.len()
+                    )))
+                }
+            })
+            .collect()
+    }
+
+    fn get_dtcs(&mut self) -> Result<Vec<Vec<Dtc>>> {
+        let result = self.obd_mode_command(0x03)?;
+        result
+            .iter()
+            .map(|response| match response.first() {
+                Some(0) => {
+                    if response.len() % 2 == 1 {
+                        let mut ret = Vec::new();
+                        for i in (1..response.len()).step_by(2) {
+                            ret.push(match response[i] >> 6 {
+                                0 => Dtc::Powertrain(0),
+                                1 => Dtc::Chassis(0),
+                                2 => Dtc::Body(0),
+                                3 => Dtc::Network(0),
+                                _ => unreachable!(),
+                            });
+                        }
+                        Ok(ret)
+                    } else {
+                        Err(Error::Other(format!(
+                            "invalid response when getting DTCs {:?}",
+                            response
+                        )))
+                    }
+                }
+                Some(n) if *n <= 3 => todo!(),
+                Some(_) => Err(Error::Other(format!(
+                    "invalid response {:?} when getting DTCs",
+                    response
+                ))),
+                None => Err(Error::Other(
+                    "no response bytes when getting DTCs".to_owned(),
+                )),
+            })
+            .collect::<Result<Vec<Vec<Dtc>>>>()
+    }
+
+    fn get_rpm(&mut self) -> Result<f32> {
+        let result = self.obd_command_cnt_len::<1, 2>(0x01, 0x0C)?[0];
+        Ok(f32::from(u16::from_be_bytes(result)) / 4.0)
+    }
+
+    fn get_speed(&mut self) -> Result<u8> {
+        Ok(self.obd_command_cnt_len::<1, 1>(0x01, 0x0C)?[0][0])
+    }
+}

src/commands/mod.rs

@@ -0,0 +1,42 @@
+//! High level OBD-II interface
+
+mod implementation;
+
+mod types;
+pub use types::{Dtc, DtcsInfo};
+
+use crate::Result;
+
+/// Trait for devices that can retrieve data over OBD-II
+///
+/// Automatically implemented for implementors of [Obd2Device](crate::Obd2Device).
+pub trait Obd2DataRetrieval: private::Sealed {
+    /// Check which getters are supported by the current vehicle
+    // fn get_support() -> Obd2FunctionSupport;
+
+    /// Retreive the VIN (vehicle identification number)
+    ///
+    /// This should match the number printed on the vehicle, and is a good command for checking
+    /// that the OBD-II interface is working correctly.
+    fn get_vin(&mut self) -> Result<String>;
+
+    /// Get DTC (diagnostic trouble code) metadata for each ECU
+    fn get_dtc_info(&mut self) -> Result<Vec<DtcsInfo>>;
+
+    /// Get DTCs for each ECU
+    fn get_dtcs(&mut self) -> Result<Vec<Vec<Dtc>>>;
+
+    /// Get the calculated engine
+    // fn get_engine_load(&mut self) -> Result<u8>;
+
+    /// Get the RPM in increments of 0.25
+    fn get_rpm(&mut self) -> Result<f32>;
+
+    /// Get the speed in km/h
+    fn get_speed(&mut self) -> Result<u8>;
+}
+
+mod private {
+    pub trait Sealed {}
+    impl<T: crate::Obd2Device> Sealed for T {}
+}

src/commands/types.rs

@@ -0,0 +1,43 @@
+use std::fmt;
+
+/// DTC (diagnostic trouble code) metadata
+#[derive(Debug)]
+#[non_exhaustive]
+pub struct DtcsInfo {
+    /// Whether the "check engine" light is illuminated
+    pub malfunction_indicator_light: bool,
+
+    /// Number of DTCs for this ECU
+    pub dtc_count: u8,
+
+    /// Bit field showing availability of seven common tests; the upper bit is currently unused.
+    pub common_test_availability: u8,
+
+    /// Whether the engine is Diesel
+    pub is_compression_engine: bool,
+
+    /// Bit field showing availability of sixteen engine-specific tests. What the tests are is
+    /// based on the value of `is_compression_engine`.
+    pub specific_test_availability: u16,
+}
+
+/// An individual trouble code from an ECU
+#[derive(Debug)]
+pub enum Dtc {
+    Powertrain(u16),
+    Chassis(u16),
+    Body(u16),
+    Network(u16),
+}
+
+impl fmt::Display for Dtc {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let (c, n) = match self {
+            Self::Powertrain(n) => ('P', n),
+            Self::Chassis(n) => ('C', n),
+            Self::Body(n) => ('B', n),
+            Self::Network(n) => ('U', n),
+        };
+        f.write_fmt(format_args!("{}{:03X}", c, n))
+    }
+}