Split some files and add more documentation

Cargo.toml

@@ -3,7 +3,7 @@ name = "obd2"
 description = "Utility for reading data from a vehicle over OBD-II"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/rsammelson/obd2"
-version = "0.2.0-pre1"
+version = "0.2.0-pre2"
 edition = "2021"
 
 [dependencies]

examples/basic/main.rs

@@ -1,4 +1,4 @@
-use obd2::Obd2Device;
+use obd2::commands::Obd2DataRetrieval;
 
 use std::time;
 

src/commands.rs

@@ -0,0 +1,155 @@
+//! High level OBD-II interface
+
+use std::fmt;
+
+use crate::{Error, Obd2Device, Result};
+
+/// Trait for devices that can retrieve data over OBD-II
+///
+/// Automatically impelemted for implementors of [Obd2Device].
+pub trait Obd2DataRetrieval: private::Sealed {
+    /// 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 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>;
+}
+
+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])
+    }
+}
+
+/// 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))
+    }
+}
+
+mod private {
+    pub trait Sealed {}
+    impl<T: super::Obd2Device> Sealed for T {}
+}

src/device/mod.rs

@@ -1,3 +1,5 @@
+//! Lower level OBD-II interfacing structures
+
 mod elm327;
 pub use elm327::Elm327;
 

src/error.rs

@@ -0,0 +1,32 @@
+pub type Result<T> = std::result::Result<T, Error>;
+
+#[derive(thiserror::Error, Debug)]
+pub enum Error {
+    #[error("Device error: `{0:?}`")]
+    Device(DeviceError),
+    #[error("Other OBD2 error: `{0}`")]
+    Other(String),
+    #[error("Incorrect length (`{0}`): expected `{1}`, got `{2}`")]
+    IncorrectResponseLength(&'static str, usize, usize),
+}
+
+#[derive(Debug)]
+pub struct DeviceError(super::device::Error);
+
+impl From<super::device::Error> for Error {
+    fn from(e: super::device::Error) -> Self {
+        Error::Device(DeviceError(e))
+    }
+}
+
+impl From<std::num::ParseIntError> for Error {
+    fn from(e: std::num::ParseIntError) -> Self {
+        Error::Other(format!("invalid data recieved: {:?}", e))
+    }
+}
+
+impl From<std::string::FromUtf8Error> for Error {
+    fn from(e: std::string::FromUtf8Error) -> Self {
+        Error::Other(format!("invalid string recieved: {:?}", e))
+    }
+}

src/interface.rs

@@ -2,6 +2,10 @@ use log::{debug, trace};
 
 use super::{device::Obd2BaseDevice, Error, Obd2Device, Result};
 
+/// An OBD-II interface
+///
+/// Wraps an implementor of [Obd2BaseDevice] to allow for higher-level usage of the OBD-II
+/// interface.
 #[derive(Default)]
 pub struct Obd2<T: Obd2BaseDevice> {
     device: T,

src/lib.rs

@@ -1,10 +1,28 @@
+//! Crate for communicating with OBD-II (on-board diagnostics) interfaces on cars
+//!
+//! # Usage
+//! ```
+//! use obd2::{commands::Obd2DataRetrieval, device::Elm327, Obd2};
+//!
+//! fn main() -> Result<(), obd2::Error> {
+//!     let mut device = Obd2::<Elm327>::default();
+//!     println!("VIN: {}", device.get_vin()?);
+//!     Ok(())
+//! }
+//! ```
+
 #![forbid(unsafe_code)]
 
+pub mod commands;
+
 pub mod device;
 
+mod error;
+pub use error::Error;
+use error::Result;
+
 mod interface;
 pub use interface::Obd2;
 
 mod obd2_device;
-use obd2_device::Result;
+pub use obd2_device::Obd2Device;
-pub use obd2_device::{Error, Obd2Device};

src/obd2_device.rs

@@ -1,6 +1,4 @@
-use core::fmt;
+use crate::{Error, Result};
-
-pub type Result<T> = std::result::Result<T, Error>;
 
 /// A higher-level API for using an OBD-II device
 pub trait Obd2Device {
@@ -58,151 +56,4 @@ pub trait Obd2Device {
             .try_into()
             .map_err(|_| Error::IncorrectResponseLength("count", RESPONSE_COUNT, count))
     }
-
-    /// 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> {
-        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)?)
-    }
-
-    /// Get DTC (diagnostic trouble code) metadata for each ECU
-    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()
-    }
-
-    /// Get DTCs for each ECU
-    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>>>>()
-    }
-
-    /// Get the RPM in increments of 0.25
-    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)
-    }
-
-    /// Get the speed in km/h
-    fn get_speed(&mut self) -> Result<u8> {
-        Ok(self.obd_command_cnt_len::<1, 1>(0x01, 0x0C)?[0][0])
-    }
-}
-
-#[allow(dead_code)]
-#[derive(Debug)]
-pub struct DtcsInfo {
-    malfunction_indicator_light: bool,
-    dtc_count: u8,
-    common_test_availability: u8,
-    is_compression_engine: bool,
-    specific_test_availability: u16,
-}
-
-#[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))
-    }
-}
-
-#[derive(thiserror::Error, Debug)]
-pub enum Error {
-    #[error("Device error: `{0:?}`")]
-    Device(DeviceError),
-    #[error("Other OBD2 error: `{0}`")]
-    Other(String),
-    #[error("Incorrect length (`{0}`): expected `{1}`, got `{2}`")]
-    IncorrectResponseLength(&'static str, usize, usize),
-}
-
-#[derive(Debug)]
-pub struct DeviceError(super::device::Error);
-
-impl From<super::device::Error> for Error {
-    fn from(e: super::device::Error) -> Self {
-        Error::Device(DeviceError(e))
-    }
-}
-
-impl From<std::num::ParseIntError> for Error {
-    fn from(e: std::num::ParseIntError) -> Self {
-        Error::Other(format!("invalid data recieved: {:?}", e))
-    }
-}
-
-impl From<std::string::FromUtf8Error> for Error {
-    fn from(e: std::string::FromUtf8Error) -> Self {
-        Error::Other(format!("invalid string recieved: {:?}", e))
-    }
 }