sval_buffer/
error.rs

1use crate::std::fmt;
2
3/**
4An error encountered buffering data.
5*/
6#[derive(Debug)]
7pub struct Error(ErrorKind);
8
9#[derive(Debug)]
10enum ErrorKind {
11    Unsupported {
12        actual: &'static str,
13        expected: &'static str,
14    },
15    InvalidValue {
16        reason: &'static str,
17    },
18    OutsideContainer {
19        method: &'static str,
20    },
21    #[allow(dead_code)] // debug builds never reach this variant
22    NoAlloc {
23        method: &'static str,
24    },
25}
26
27impl fmt::Display for Error {
28    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
29        match self.0 {
30            ErrorKind::Unsupported { actual, expected } => {
31                write!(f, "unexpected {}, expected {}", actual, expected)
32            }
33            ErrorKind::InvalidValue { reason } => {
34                write!(f, "the value is invalid: {}", reason)
35            }
36            ErrorKind::OutsideContainer { method } => {
37                write!(f, "expected a fragment while buffering {}", method)
38            }
39            ErrorKind::NoAlloc { method } => write!(f, "cannot allocate for {}", method),
40        }
41    }
42}
43
44impl Error {
45    pub(crate) fn unsupported(expected: &'static str, actual: &'static str) -> Self {
46        Error(ErrorKind::Unsupported { actual, expected })
47    }
48
49    pub(crate) fn outside_container(method: &'static str) -> Self {
50        Error(ErrorKind::OutsideContainer { method })
51    }
52
53    /**
54    The given value is invalid.
55    */
56    pub(crate) fn invalid_value(reason: &'static str) -> Self {
57        Error(ErrorKind::InvalidValue { reason })
58    }
59
60    #[track_caller]
61    pub(crate) fn no_alloc(method: &'static str) -> Self {
62        /*
63        Users may not know they aren't depending on an allocator when using `sval_buffer`
64        and have buffering fail unexpectedly. In debug builds we provide a more developer-centric
65        panic message if this happens so they can decide whether failure to buffer is acceptable
66        or not, and enable features accordingly.
67
68        If you're not depending on `sval_buffer` directly, but through another library like
69        `sval_serde`, then you can enable their `alloc` or `std` features instead.
70        */
71
72        #[cfg(all(debug_assertions, not(feature = "no_debug_assertions"), not(test)))]
73        {
74            panic!("attempt to allocate for {} would fail; add the `alloc` feature of `sval_buffer` or the depdendent `sval_*` library to support allocation. This call will error instead of panicking in release builds. Add the `feature = no_debug_assertions` feature of `sval_buffer` if this error is expected.", method);
75        }
76        #[cfg(not(all(debug_assertions, not(feature = "no_debug_assertions"), not(test))))]
77        {
78            Error(ErrorKind::NoAlloc { method })
79        }
80    }
81}
82
83#[cfg(feature = "std")]
84mod std_support {
85    use super::*;
86
87    use crate::std::error;
88
89    impl error::Error for Error {}
90}
sval_buffer/error.rs

sval_buffer/
error.rs
