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 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201
use crate::fmt;
/// A struct containing information about the location of a panic.
///
/// This structure is created by [`PanicHookInfo::location()`] and [`PanicInfo::location()`].
///
/// [`PanicInfo::location()`]: crate::panic::PanicInfo::location
/// [`PanicHookInfo::location()`]: ../../std/panic/struct.PanicHookInfo.html#method.location
///
/// # Examples
///
/// ```should_panic
/// use std::panic;
///
/// panic::set_hook(Box::new(|panic_info| {
/// if let Some(location) = panic_info.location() {
/// println!("panic occurred in file '{}' at line {}", location.file(), location.line());
/// } else {
/// println!("panic occurred but can't get location information...");
/// }
/// }));
///
/// panic!("Normal panic");
/// ```
///
/// # Comparisons
///
/// Comparisons for equality and ordering are made in file, line, then column priority.
/// Files are compared as strings, not `Path`, which could be unexpected.
/// See [`Location::file`]'s documentation for more discussion.
#[lang = "panic_location"]
#[derive(Copy, Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
#[stable(feature = "panic_hooks", since = "1.10.0")]
pub struct Location<'a> {
file: &'a str,
line: u32,
col: u32,
}
impl<'a> Location<'a> {
/// Returns the source location of the caller of this function. If that function's caller is
/// annotated then its call location will be returned, and so on up the stack to the first call
/// within a non-tracked function body.
///
/// # Examples
///
/// ```
/// use std::panic::Location;
///
/// /// Returns the [`Location`] at which it is called.
/// #[track_caller]
/// fn get_caller_location() -> &'static Location<'static> {
/// Location::caller()
/// }
///
/// /// Returns a [`Location`] from within this function's definition.
/// fn get_just_one_location() -> &'static Location<'static> {
/// get_caller_location()
/// }
///
/// let fixed_location = get_just_one_location();
/// assert_eq!(fixed_location.file(), file!());
/// assert_eq!(fixed_location.line(), 14);
/// assert_eq!(fixed_location.column(), 5);
///
/// // running the same untracked function in a different location gives us the same result
/// let second_fixed_location = get_just_one_location();
/// assert_eq!(fixed_location.file(), second_fixed_location.file());
/// assert_eq!(fixed_location.line(), second_fixed_location.line());
/// assert_eq!(fixed_location.column(), second_fixed_location.column());
///
/// let this_location = get_caller_location();
/// assert_eq!(this_location.file(), file!());
/// assert_eq!(this_location.line(), 28);
/// assert_eq!(this_location.column(), 21);
///
/// // running the tracked function in a different location produces a different value
/// let another_location = get_caller_location();
/// assert_eq!(this_location.file(), another_location.file());
/// assert_ne!(this_location.line(), another_location.line());
/// assert_ne!(this_location.column(), another_location.column());
/// ```
#[must_use]
#[stable(feature = "track_caller", since = "1.46.0")]
#[rustc_const_stable(feature = "const_caller_location", since = "1.79.0")]
#[track_caller]
#[inline]
pub const fn caller() -> &'static Location<'static> {
crate::intrinsics::caller_location()
}
/// Returns the name of the source file from which the panic originated.
///
/// # `&str`, not `&Path`
///
/// The returned name refers to a source path on the compiling system, but it isn't valid to
/// represent this directly as a `&Path`. The compiled code may run on a different system with
/// a different `Path` implementation than the system providing the contents and this library
/// does not currently have a different "host path" type.
///
/// The most surprising behavior occurs when "the same" file is reachable via multiple paths in
/// the module system (usually using the `#[path = "..."]` attribute or similar), which can
/// cause what appears to be identical code to return differing values from this function.
///
/// # Cross-compilation
///
/// This value is not suitable for passing to `Path::new` or similar constructors when the host
/// platform and target platform differ.
///
/// # Examples
///
/// ```should_panic
/// use std::panic;
///
/// panic::set_hook(Box::new(|panic_info| {
/// if let Some(location) = panic_info.location() {
/// println!("panic occurred in file '{}'", location.file());
/// } else {
/// println!("panic occurred but can't get location information...");
/// }
/// }));
///
/// panic!("Normal panic");
/// ```
#[must_use]
#[stable(feature = "panic_hooks", since = "1.10.0")]
#[rustc_const_stable(feature = "const_location_fields", since = "1.79.0")]
#[inline]
pub const fn file(&self) -> &str {
self.file
}
/// Returns the line number from which the panic originated.
///
/// # Examples
///
/// ```should_panic
/// use std::panic;
///
/// panic::set_hook(Box::new(|panic_info| {
/// if let Some(location) = panic_info.location() {
/// println!("panic occurred at line {}", location.line());
/// } else {
/// println!("panic occurred but can't get location information...");
/// }
/// }));
///
/// panic!("Normal panic");
/// ```
#[must_use]
#[stable(feature = "panic_hooks", since = "1.10.0")]
#[rustc_const_stable(feature = "const_location_fields", since = "1.79.0")]
#[inline]
pub const fn line(&self) -> u32 {
self.line
}
/// Returns the column from which the panic originated.
///
/// # Examples
///
/// ```should_panic
/// use std::panic;
///
/// panic::set_hook(Box::new(|panic_info| {
/// if let Some(location) = panic_info.location() {
/// println!("panic occurred at column {}", location.column());
/// } else {
/// println!("panic occurred but can't get location information...");
/// }
/// }));
///
/// panic!("Normal panic");
/// ```
#[must_use]
#[stable(feature = "panic_col", since = "1.25.0")]
#[rustc_const_stable(feature = "const_location_fields", since = "1.79.0")]
#[inline]
pub const fn column(&self) -> u32 {
self.col
}
}
#[unstable(
feature = "panic_internals",
reason = "internal details of the implementation of the `panic!` and related macros",
issue = "none"
)]
impl<'a> Location<'a> {
#[doc(hidden)]
pub const fn internal_constructor(file: &'a str, line: u32, col: u32) -> Self {
Location { file, line, col }
}
}
#[stable(feature = "panic_hook_display", since = "1.26.0")]
impl fmt::Display for Location<'_> {
fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(formatter, "{}:{}:{}", self.file, self.line, self.col)
}
}