2 releases (1 stable)
1.0.0 | Nov 20, 2020 |
---|---|
0.1.0 | Nov 12, 2020 |
#20 in #error-chain
29 downloads per month
Used in embedded-error-chain
32KB
660 lines
embedded-error-chain
Easy error handling for embedded devices (no liballoc
and no_std
).
Errors are represented by error codes and come from enums that implement the
ErrorCategory
trait (a derive macro exists), which is used for custom debug
printing per error code among other things. Each error code can have a value from 0
to 15
(4 bits) and you can chain an error with up to four different error codes of
different categories.
The Error
type encapsulates an error code and error chain, and is only a single
u32
in size. There is also an untyped DynError
type, which unlike Error
does not have a type parameter for the current error code. Its size is a u32
+
pointer (usize
), which can be used to forward source errors of different categories
to the caller.
This library was inspired by libraries such as
error-chain,
anyhow and
thiserror, though it was made to work in no_std
and no liballoc
environments with very little memory overhead.
Example
use embedded_error_chain::prelude::*;
#[derive(Clone, Copy, ErrorCategory)]
#[repr(u8)]
enum SpiError {
BusError,
// ...
}
static LAST_GYRO_ACC_READOUT: usize = 200;
#[derive(Clone, Copy, ErrorCategory)]
#[error_category(links(SpiError))]
#[repr(u8)]
enum GyroAccError {
InitFailed,
#[error("{variant} (readout={})", LAST_GYRO_ACC_READOUT)]
ReadoutFailed,
/// Value must be in range [0, 256)
#[error("{variant}: {summary}")]
InvalidValue,
}
fn main() {
if let Err(err) = calibrate() {
// log the error
println!("{:?}", err);
// ...
}
let readout = match gyro_acc_readout() {
Ok(val) => val,
Err(err) => {
if let Some(spi_error) = err.code_of_category::<SpiError>() {
// try to fix it
0
}
else {
panic!("unfixable spi error");
}
}
};
}
fn spi_init() -> Result<(), SpiError> {
Err(SpiError::BusError)
}
fn gyro_acc_init() -> Result<(), Error<GyroAccError>> {
spi_init().chain_err(GyroAccError::InitFailed)?;
Ok(())
}
fn gyro_acc_readout() -> Result<u32, Error<GyroAccError>> {
Err(SpiError::BusError.chain(GyroAccError::InvalidValue))
}
fn calibrate() -> Result<(), DynError> {
gyro_acc_init()?;
// other stuff...
Ok(())
}
License: MIT
lib.rs
:
Derive macros for embedded-error-chain.
Dependencies
~1.5MB
~35K SLoC