gix_error/exn/
macros.rs

1// Copyright 2025 FastLabs Developers
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15/// Creates an [`Exn`] and returns it as [`Result`].
16///
17/// Shorthand for `return Err(Exn::from(err))`.
18///
19/// # Examples
20///
21/// Create an [`Exn`] from [`Error`]:
22///
23/// [`Exn`]: crate::Exn
24/// [`Error`]: std::error::Error
25///
26/// ```
27/// use std::fs;
28///
29/// use gix_error::bail;
30/// # fn wrapper() -> Result<(), gix_error::Exn<std::io::Error>> {
31/// match fs::read_to_string("/path/to/file") {
32///     Ok(content) => println!("file contents: {content}"),
33///     Err(err) => bail!(err),
34/// }
35/// # Ok(()) }
36/// ```
37#[macro_export]
38macro_rules! bail {
39    ($err:expr) => {{
40        return ::std::result::Result::Err($crate::Exn::from($err));
41    }};
42}
43
44/// Ensures `$cond` is met; otherwise return an error.
45///
46/// Shorthand for `if !$cond { bail!(...); }`.
47///
48/// # Examples
49///
50/// Create an [`Exn`] from an [`Error`]:
51///
52/// [`Exn`]: crate::Exn
53/// [`Error`]: std::error::Error
54///
55/// ```
56/// # fn has_permission(_: &u32, _: &u32) -> bool { true }
57/// # type User = u32;
58/// # let user = 0;
59/// # type Resource = u32;
60/// # let resource = 0;
61/// use std::error::Error;
62/// use std::fmt;
63///
64/// use gix_error::ensure;
65///
66/// #[derive(Debug)]
67/// struct PermissionDenied(User, Resource);
68///
69/// impl fmt::Display for PermissionDenied {
70///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
71///         write!(fmt, "permission denied")
72///     }
73/// }
74///
75/// impl Error for PermissionDenied {}
76///
77/// ensure!(
78///     has_permission(&user, &resource),
79///     PermissionDenied(user, resource),
80/// );
81/// # Ok(())
82/// ```
83#[macro_export]
84macro_rules! ensure {
85    ($cond:expr, $err:expr $(,)?) => {{
86        if !bool::from($cond) {
87            $crate::bail!($err)
88        }
89    }};
90}
91
92/// Construct a [`Message`](crate::Message) from a string literal or format string.
93/// Note that it always runs `format!()`, use the [`message()`](crate::message()) function for literals instead.
94#[macro_export]
95macro_rules! message {
96    ($message_with_format_args:literal $(,)?) => {
97        $crate::Message::new(format!($message_with_format_args))
98    };
99    ($fmt:expr, $($arg:tt)*) => {
100        $crate::Message::new(format!($fmt, $($arg)*))
101    };
102}
gix_error/exn/macros.rs

gix_error/exn/
macros.rs
