weavatrix_scan/
error.rs

1use std::fmt;
2use std::path::PathBuf;
3
4pub type Result<T> = std::result::Result<T, Error>;
5
6#[derive(Debug)]
7pub enum Error {
8    Io {
9        path: PathBuf,
10        source: std::io::Error,
11    },
12    InvalidRoot(PathBuf),
13    ConcurrentModification(PathBuf),
14    /// A paged read targeted a snapshot that the session has already replaced.
15    StaleSnapshot {
16        /// Generation supplied by the page cursor.
17        expected: u64,
18        /// Generation of the session's current snapshot.
19        actual: u64,
20    },
21}
22
23impl Error {
24    pub(crate) fn io(path: impl Into<PathBuf>, source: std::io::Error) -> Self {
25        Self::Io {
26            path: path.into(),
27            source,
28        }
29    }
30
31    pub(crate) fn concurrent_modification(path: impl Into<PathBuf>) -> Self {
32        Self::ConcurrentModification(path.into())
33    }
34
35    /// Builds a stale-generation error for a paged session read.
36    #[must_use]
37    pub const fn stale_snapshot(expected: u64, actual: u64) -> Self {
38        Self::StaleSnapshot { expected, actual }
39    }
40}
41
42impl fmt::Display for Error {
43    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
44        match self {
45            Self::Io { path, source } => write!(formatter, "{}: {source}", path.display()),
46            Self::InvalidRoot(path) => write!(formatter, "not a directory: {}", path.display()),
47            Self::ConcurrentModification(path) => {
48                write!(formatter, "file changed while scanning: {}", path.display())
49            }
50            Self::StaleSnapshot { expected, actual } => write!(
51                formatter,
52                "scan snapshot generation {expected} is stale; current generation is {actual}"
53            ),
54        }
55    }
56}
57
58impl std::error::Error for Error {
59    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
60        match self {
61            Self::Io { source, .. } => Some(source),
62            Self::InvalidRoot(_) | Self::ConcurrentModification(_) | Self::StaleSnapshot { .. } => {
63                None
64            }
65        }
66    }
67}
weavatrix_scan/error.rs

weavatrix_scan/
error.rs
