scroll/
error.rs

1use core::fmt::{self, Display};
2use core::{error, result};
3#[cfg(feature = "std")]
4use std::io;
5
6#[derive(Debug)]
7/// A custom Scroll error
8pub enum Error {
9    /// The type you tried to read was too big
10    TooBig {
11        size: usize,
12        len: usize,
13    },
14    /// The requested offset to read/write at is invalid
15    BadOffset(usize),
16    BadInput {
17        size: usize,
18        msg: &'static str,
19    },
20    /// A custom Scroll error for reporting messages to clients.
21    /// For no-std, use [`Error::BadInput`] with a static string.
22    #[cfg(feature = "std")]
23    Custom(String),
24    /// Returned when IO based errors are encountered
25    #[cfg(feature = "std")]
26    IO(io::Error),
27}
28
29impl error::Error for Error {
30    fn description(&self) -> &str {
31        match self {
32            Error::TooBig { .. } => "TooBig",
33            Error::BadOffset(_) => "BadOffset",
34            Error::BadInput { .. } => "BadInput",
35            #[cfg(feature = "std")]
36            Error::Custom(_) => "Custom",
37            #[cfg(feature = "std")]
38            Error::IO(_) => "IO",
39        }
40    }
41    fn cause(&self) -> Option<&dyn error::Error> {
42        match self {
43            Error::TooBig { .. } => None,
44            Error::BadOffset(_) => None,
45            Error::BadInput { .. } => None,
46            #[cfg(feature = "std")]
47            Error::Custom(_) => None,
48            #[cfg(feature = "std")]
49            Error::IO(io) => io.source(),
50        }
51    }
52}
53
54#[cfg(feature = "std")]
55impl From<io::Error> for Error {
56    fn from(err: io::Error) -> Error {
57        Error::IO(err)
58    }
59}
60
61impl Display for Error {
62    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
63        match self {
64            Error::TooBig { size, len } => {
65                write!(fmt, "type is too big ({size}) for {len}")
66            }
67            Error::BadOffset(offset) => {
68                write!(fmt, "bad offset {offset}")
69            }
70            Error::BadInput { msg, size } => {
71                write!(fmt, "bad input {msg} ({size})")
72            }
73            #[cfg(feature = "std")]
74            Error::Custom(msg) => {
75                write!(fmt, "{msg}")
76            }
77            #[cfg(feature = "std")]
78            Error::IO(err) => {
79                write!(fmt, "{err}")
80            }
81        }
82    }
83}
84
85pub type Result<T> = result::Result<T, Error>;
scroll/error.rs

scroll/
error.rs
