platform/blade: Improve `ZED_DEVICE_ID` parsing (#29235)

Ben Kunkle created 8 months ago

Closes #28533

Release Notes:

- Linux: Improved parsing of `ZED_DEVICE_ID` environment variable in an
attempt to fix some cases where it erroneously failed to parse. The
`ZED_DEVICE_ID` is now expected to always be a 4 digit hexadecimal
number (as it is in the output of `lcpci`) with an optional `0x` or `0X`
prefix.

Change summary

crates/gpui/src/platform/blade/blade_context.rs | 47 ++++++++++++++++++
1 file changed, 45 insertions(+), 2 deletions(-)

Detailed changes

crates/gpui/src/platform/blade/blade_context.rs

@@ -11,8 +11,7 @@ pub struct BladeContext {
 impl BladeContext {
     pub fn new() -> anyhow::Result<Self> {
         let device_id_forced = match std::env::var("ZED_DEVICE_ID") {
-            Ok(val) => val
-                .parse()
+            Ok(val) => parse_pci_id(&val)
                 .context("Failed to parse device ID from `ZED_DEVICE_ID` environment variable")
                 .log_err(),
             Err(std::env::VarError::NotPresent) => None,
@@ -36,3 +35,47 @@ impl BladeContext {
         Ok(Self { gpu })
     }
 }
+
+fn parse_pci_id(id: &str) -> anyhow::Result<u32> {
+    let mut id = id.trim();
+
+    if id.starts_with("0x") || id.starts_with("0X") {
+        id = &id[2..];
+    }
+    let is_hex_string = id.chars().all(|c| c.is_ascii_hexdigit());
+    let is_4_chars = id.len() == 4;
+    anyhow::ensure!(
+        is_4_chars && is_hex_string,
+        "Expected a 4 digit PCI ID in hexadecimal format"
+    );
+
+    return u32::from_str_radix(id, 16)
+        .map_err(|_| anyhow::anyhow!("Failed to parse PCI ID as hex"));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::parse_pci_id;
+
+    #[test]
+    fn test_parse_device_id() {
+        assert!(parse_pci_id("0xABCD").is_ok());
+        assert!(parse_pci_id("ABCD").is_ok());
+        assert!(parse_pci_id("abcd").is_ok());
+        assert!(parse_pci_id("1234").is_ok());
+        assert!(parse_pci_id("123").is_err());
+        assert_eq!(
+            parse_pci_id(&format!("{:x}", 0x1234)).unwrap(),
+            parse_pci_id(&format!("{:X}", 0x1234)).unwrap(),
+        );
+
+        assert_eq!(
+            parse_pci_id(&format!("{:#x}", 0x1234)).unwrap(),
+            parse_pci_id(&format!("{:#X}", 0x1234)).unwrap(),
+        );
+        assert_eq!(
+            parse_pci_id(&format!("{:#x}", 0x1234)).unwrap(),
+            parse_pci_id(&format!("{:#X}", 0x1234)).unwrap(),
+        );
+    }
+}