1//! Error types used and generated by Calloop.
2//!
3//! This module contains error types for Calloop's operations. They are designed
4//! to make it easy to deal with errors arising from Calloop's internal I/O and
5//! other operations.
6//!
7//! There are two top-level error types:
8//!
9//! - [`Error`]: used by callback functions, internal operations, and some event
10//! loop API calls
11//!
12//! - [`InsertError`]: used primarily by the [`insert_source()`] method when an
13//! event source cannot be added to the loop and needs to be given back to the
14//! caller
15//!
16//! [`insert_source()`]: crate::LoopHandle::insert_source()
17
18use std::fmt::{self, Debug, Formatter};
19
20/// The primary error type used by Calloop covering internal errors and I/O
21/// errors that arise during loop operations such as source registration or
22/// event dispatching.
23#[derive(Debug)]
24pub enum Error {
25 /// When an event source is registered (or re- or un-registered) with the
26 /// event loop, this error variant will occur if the token Calloop uses to
27 /// keep track of the event source is not valid.
28 InvalidToken,
29
30 /// This variant wraps a [`std::io::Error`], which might arise from
31 /// Calloop's internal operations.
32 IoError(std::io::Error),
33
34 /// Any other unexpected error kind (most likely from a user implementation of
35 /// [`EventSource::process_events()`]) will be wrapped in this.
36 ///
37 /// [`EventSource::process_events()`]: crate::EventSource::process_events()
38 OtherError(Box<dyn std::error::Error + Sync + Send>),
39}
40
41impl fmt::Display for Error {
42 #[cfg_attr(feature = "nightly_coverage", coverage(off))]
43 fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
44 match self {
45 Self::InvalidToken => f.write_str(data:"invalid token provided to internal function"),
46 Self::IoError(err: &Error) => write!(f, "underlying IO error: {}", err),
47 Self::OtherError(err: &Box) => write!(f, "other error during loop operation: {}", err),
48 }
49 }
50}
51
52impl From<std::io::Error> for Error {
53 #[cfg_attr(feature = "nightly_coverage", coverage(off))]
54 fn from(value: std::io::Error) -> Self {
55 Self::IoError(value)
56 }
57}
58
59impl From<Box<dyn std::error::Error + Sync + Send>> for Error {
60 #[cfg_attr(feature = "nightly_coverage", coverage(off))]
61 fn from(value: Box<dyn std::error::Error + Sync + Send>) -> Self {
62 Self::OtherError(value)
63 }
64}
65
66impl From<Error> for std::io::Error {
67 /// Converts Calloop's error type into a [`std::io::Error`].
68 #[cfg_attr(feature = "nightly_coverage", coverage(off))]
69 fn from(err: Error) -> Self {
70 match err {
71 Error::IoError(source: Error) => source,
72 Error::InvalidToken => Self::new(kind:std::io::ErrorKind::InvalidInput, error:err.to_string()),
73 Error::OtherError(source: Box) => Self::new(kind:std::io::ErrorKind::Other, error:source),
74 }
75 }
76}
77
78impl std::error::Error for Error {
79 #[cfg_attr(feature = "nightly_coverage", coverage(off))]
80 fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
81 match self {
82 Self::InvalidToken => None,
83 Self::IoError(err: &Error) => Some(err),
84 Self::OtherError(err: &Box) => Some(&**err),
85 }
86 }
87}
88
89/// [`Result`] alias using Calloop's error type.
90pub type Result<T> = core::result::Result<T, Error>;
91
92/// An error generated when trying to insert an event source
93pub struct InsertError<T> {
94 /// The source that could not be inserted
95 pub inserted: T,
96 /// The generated error
97 pub error: Error,
98}
99
100impl<T> Debug for InsertError<T> {
101 #[cfg_attr(feature = "nightly_coverage", coverage(off))]
102 fn fmt(&self, formatter: &mut Formatter) -> core::result::Result<(), fmt::Error> {
103 write!(formatter, "{:?}", self.error)
104 }
105}
106
107impl<T> fmt::Display for InsertError<T> {
108 #[cfg_attr(feature = "nightly_coverage", coverage(off))]
109 fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
110 write!(f, "error inserting event source: {}", &self.error)
111 }
112}
113
114impl<T> From<InsertError<T>> for crate::Error {
115 /// Converts the [`InsertError`] into Calloop's error type, throwing away
116 /// the contained source.
117 #[cfg_attr(feature = "nightly_coverage", coverage(off))]
118 fn from(e: InsertError<T>) -> crate::Error {
119 e.error
120 }
121}
122
123impl<T> std::error::Error for InsertError<T> {
124 #[cfg_attr(feature = "nightly_coverage", coverage(off))]
125 fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
126 Some(&self.error)
127 }
128}
129