bherbruckandClaude Opus 5.5
296683229d
* WIP deep rename (not for push) * WIP2 * WIP3 * WIP4 wxs fix * rustfmt * Rename the remaining identifiers in merged crash-report code Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT --------- Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
58 lines
2.1 KiB
Rust
58 lines
2.1 KiB
Rust
//! Finding a 3D mouse on Linux. The kernel exposes every HID interface as `/dev/hidrawN`, with
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//! its identity and report descriptor under `/sys/class/hidraw/hidrawN/device/`. Reading both is
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//! plain file I/O, so no udev or hidapi library is needed.
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use std::path::{Path, PathBuf};
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use super::hid_descriptor::{Descriptor, Layout};
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const SYSFS: &str = "/sys/class/hidraw";
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const DEV: &str = "/dev";
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pub struct Device {
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pub path: PathBuf,
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pub layout: Layout,
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}
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/// The vendor id from `HID_ID=<bus>:<vendor>:<product>` (all hexadecimal) in a sysfs `uevent`.
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fn vendor_id(uevent: &str) -> Option<u16> {
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let id = uevent.lines().find_map(|line| line.strip_prefix("HID_ID="))?;
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let vendor = id.split(':').nth(1)?;
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u32::from_str_radix(vendor.trim(), 16).ok().and_then(|vendor| u16::try_from(vendor).ok())
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}
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/// The first hidraw interface that is a 3D mouse's multi-axis controller.
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pub fn find() -> Option<Device> {
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let mut names: Vec<_> = std::fs::read_dir(SYSFS).ok()?.filter_map(Result::ok).map(|entry| entry.file_name()).collect();
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names.sort();
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names.into_iter().find_map(|name| probe(&Path::new(SYSFS).join(&name), Path::new(DEV).join(&name)))
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}
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fn probe(sysfs: &Path, path: PathBuf) -> Option<Device> {
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let uevent = std::fs::read_to_string(sysfs.join("device/uevent")).ok()?;
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if !super::is_3d_mouse_vendor(vendor_id(&uevent)?) {
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return None;
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}
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let descriptor = Descriptor::parse(&std::fs::read(sysfs.join("device/report_descriptor")).ok()?);
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descriptor.is_multi_axis_controller().then(|| Device { path, layout: descriptor.layout() })
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn reads_the_vendor_from_the_hid_id() {
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let uevent = "DRIVER=hid-generic\nHID_ID=0003:0000256F:0000C631\nHID_NAME=Some Device\n";
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assert_eq!(vendor_id(uevent), Some(0x256f));
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assert_eq!(vendor_id("HID_ID=0003:0000046D:0000C077"), Some(0x046d));
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}
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#[test]
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fn malformed_ids_are_rejected() {
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for uevent in ["", "HID_NAME=x", "HID_ID=", "HID_ID=0003", "HID_ID=0003:zzzz:0001", "HID_ID=0003:FFFFFFFF:0001"] {
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assert_eq!(vendor_id(uevent), None, "{uevent:?}");
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}
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}
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}
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