cr1140_hal/
error.rs

1// SPDX-License-Identifier: GPL-3.0-only
2//! Unified error type for the HAL. Wraps the OS errors the underlying ABIs
3//! return (`std::io::Error`) and adds HAL-specific failure causes so callers
4//! can distinguish "no such device" from "wrong pixel format" from a plain I/O
5//! error without string-matching.
6
7/// Errors returned by `cr1140-hal`.
8#[derive(Debug, thiserror::Error)]
9pub enum HalError {
10    /// An underlying OS / I/O error (open, ioctl, sysfs read/write).
11    #[error("io: {0}")]
12    Io(#[from] std::io::Error),
13    /// A device or node could not be located (e.g. no input matched a name).
14    #[error("device not found: {0}")]
15    DeviceNotFound(String),
16    /// The framebuffer is not the expected xRGB8888/32bpp layout.
17    #[error("unsupported framebuffer format: {0}")]
18    UnsupportedFormat(String),
19    /// A value was outside the hardware's accepted range.
20    #[error("value out of range: {0}")]
21    OutOfRange(String),
22    /// A sysfs/procfs value could not be parsed.
23    #[error("parse error: {0}")]
24    Parse(String),
25}
26
27/// `Result` specialised to [`HalError`].
28pub type HalResult<T> = Result<T, HalError>;
29
30/// Degrade a [`HalError`] back to an [`std::io::Error`] so existing
31/// `io::Result`-based callers (e.g. `cr1140-sdk`) keep composing with `?`.
32/// The [`HalError::Io`] variant is returned as-is; the rest map to
33/// [`std::io::ErrorKind::Other`] preserving the message.
34impl From<HalError> for std::io::Error {
35    fn from(e: HalError) -> Self {
36        match e {
37            HalError::Io(io) => io,
38            other => std::io::Error::other(other.to_string()),
39        }
40    }
41}
42
43#[cfg(test)]
44mod tests {
45    use super::*;
46
47    #[test]
48    fn io_error_converts_via_from() {
49        let io = std::io::Error::new(std::io::ErrorKind::PermissionDenied, "nope");
50        let err: HalError = io.into();
51        assert!(matches!(err, HalError::Io(_)));
52    }
53
54    #[test]
55    fn display_strings_name_the_cause() {
56        assert_eq!(
57            HalError::DeviceNotFound("ifm-keypad".into()).to_string(),
58            "device not found: ifm-keypad"
59        );
60        assert_eq!(
61            HalError::UnsupportedFormat("16 bpp".into()).to_string(),
62            "unsupported framebuffer format: 16 bpp"
63        );
64        assert_eq!(
65            HalError::OutOfRange("500 > 400".into()).to_string(),
66            "value out of range: 500 > 400"
67        );
68    }
69
70    #[test]
71    fn io_variant_round_trips_back_to_io_error() {
72        let original = std::io::Error::new(std::io::ErrorKind::NotFound, "gone");
73        let io: std::io::Error = HalError::from(original).into();
74        assert_eq!(io.kind(), std::io::ErrorKind::NotFound);
75    }
76
77    #[test]
78    fn non_io_variant_degrades_to_other_kind() {
79        let io: std::io::Error = HalError::DeviceNotFound("x".into()).into();
80        assert_eq!(io.kind(), std::io::ErrorKind::Other);
81        assert!(io.to_string().contains("device not found: x"));
82    }
83
84    #[test]
85    fn question_mark_propagates_io_as_hal_error() {
86        fn inner() -> HalResult<String> {
87            let s = std::fs::read_to_string("/definitely/not/a/real/path/xyz")?;
88            Ok(s)
89        }
90        assert!(matches!(inner(), Err(HalError::Io(_))));
91    }
92}
cr1140_hal/error.rs

cr1140_hal/
error.rs
