1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59

/// A specialized [`Result`] type that provides compiler error information.
pub type Result<T> = std::result::Result<T, Error>;

/// An error object consists of both an error message and file and line information.
#[derive(Default, Debug)]
pub struct Error {
    message: String,
    path: String,
    span: Option<(usize, usize)>,
}

impl std::error::Error for Error {}

impl From<Error> for std::io::Error {
    fn from(error: Error) -> Self {
        std::io::Error::new(std::io::ErrorKind::Other, error.message.as_str())
    }
}

impl From<syn::Error> for Error {
    fn from(error: syn::Error) -> Self {
        let start = error.span().start();
        Self {
            message: error.to_string(),
            span: Some((start.line, start.column)),
            ..Self::default()
        }
    }
}

impl std::fmt::Display for Error {
    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        writeln!(fmt, "error: {}", self.message)?;
        if !self.path.is_empty() {
            if let Some((line, column)) = self.span {
                writeln!(fmt, "  --> {}:{line}:{column}", self.path)?;
            } else {
                writeln!(fmt, "  --> {}", self.path)?;
            }
        }
        Ok(())
    }
}

impl Error {
    pub(crate) fn new(message: &str) -> Self {
        Self {
            message: message.to_string(),
            ..Self::default()
        }
    }

    pub(crate) fn with_path(self, path: &str) -> Self {
        Self {
            path: path.to_string(),
            ..self
        }
    }
}