|
4 | 4 |
|
5 | 5 | use crate::any::Any; |
6 | 6 | use crate::collections; |
| 7 | +use crate::fmt; |
7 | 8 | use crate::panicking; |
8 | 9 | use crate::sync::atomic::{AtomicUsize, Ordering}; |
9 | 10 | use crate::sync::{Mutex, RwLock}; |
10 | 11 | use crate::thread::Result; |
11 | 12 |
|
| 13 | +/// A struct providing information about a panic. |
| 14 | +/// |
| 15 | +/// `PanicInfo` structure is passed to a panic hook set by the [`set_hook`] |
| 16 | +/// function. |
| 17 | +/// |
| 18 | +/// [`set_hook`]: ../../std/panic/fn.set_hook.html |
| 19 | +/// |
| 20 | +/// # Examples |
| 21 | +/// |
| 22 | +/// ```should_panic |
| 23 | +/// use std::panic; |
| 24 | +/// |
| 25 | +/// panic::set_hook(Box::new(|panic_info| { |
| 26 | +/// println!("panic occurred: {panic_info}"); |
| 27 | +/// })); |
| 28 | +/// |
| 29 | +/// panic!("critical system failure"); |
| 30 | +/// ``` |
| 31 | +#[stable(feature = "panic_hooks", since = "1.10.0")] |
| 32 | +#[derive(Debug)] |
| 33 | +pub struct PanicInfo<'a> { |
| 34 | + payload: &'a (dyn Any + Send), |
| 35 | + location: &'a Location<'a>, |
| 36 | + can_unwind: bool, |
| 37 | + force_no_backtrace: bool, |
| 38 | +} |
| 39 | + |
| 40 | +impl<'a> PanicInfo<'a> { |
| 41 | + #[unstable(feature = "panic_internals", issue = "none")] |
| 42 | + #[doc(hidden)] |
| 43 | + #[inline] |
| 44 | + pub fn internal_constructor( |
| 45 | + location: &'a Location<'a>, |
| 46 | + can_unwind: bool, |
| 47 | + force_no_backtrace: bool, |
| 48 | + ) -> Self { |
| 49 | + struct NoPayload; |
| 50 | + PanicInfo { payload: &NoPayload, location, can_unwind, force_no_backtrace } |
| 51 | + } |
| 52 | + |
| 53 | + #[unstable(feature = "panic_internals", issue = "none")] |
| 54 | + #[doc(hidden)] |
| 55 | + #[inline] |
| 56 | + pub fn set_payload(&mut self, info: &'a (dyn Any + Send)) { |
| 57 | + self.payload = info; |
| 58 | + } |
| 59 | + |
| 60 | + /// Returns the payload associated with the panic. |
| 61 | + /// |
| 62 | + /// This will commonly, but not always, be a `&'static str` or [`String`]. |
| 63 | + /// |
| 64 | + /// [`String`]: ../../std/string/struct.String.html |
| 65 | + /// |
| 66 | + /// # Examples |
| 67 | + /// |
| 68 | + /// ```should_panic |
| 69 | + /// use std::panic; |
| 70 | + /// |
| 71 | + /// panic::set_hook(Box::new(|panic_info| { |
| 72 | + /// if let Some(s) = panic_info.payload().downcast_ref::<&str>() { |
| 73 | + /// println!("panic occurred: {s:?}"); |
| 74 | + /// } else { |
| 75 | + /// println!("panic occurred"); |
| 76 | + /// } |
| 77 | + /// })); |
| 78 | + /// |
| 79 | + /// panic!("Normal panic"); |
| 80 | + /// ``` |
| 81 | + #[must_use] |
| 82 | + #[stable(feature = "panic_hooks", since = "1.10.0")] |
| 83 | + pub fn payload(&self) -> &(dyn Any + Send) { |
| 84 | + self.payload |
| 85 | + } |
| 86 | + |
| 87 | + /// Returns information about the location from which the panic originated, |
| 88 | + /// if available. |
| 89 | + /// |
| 90 | + /// This method will currently always return [`Some`], but this may change |
| 91 | + /// in future versions. |
| 92 | + /// |
| 93 | + /// # Examples |
| 94 | + /// |
| 95 | + /// ```should_panic |
| 96 | + /// use std::panic; |
| 97 | + /// |
| 98 | + /// panic::set_hook(Box::new(|panic_info| { |
| 99 | + /// if let Some(location) = panic_info.location() { |
| 100 | + /// println!("panic occurred in file '{}' at line {}", |
| 101 | + /// location.file(), |
| 102 | + /// location.line(), |
| 103 | + /// ); |
| 104 | + /// } else { |
| 105 | + /// println!("panic occurred but can't get location information..."); |
| 106 | + /// } |
| 107 | + /// })); |
| 108 | + /// |
| 109 | + /// panic!("Normal panic"); |
| 110 | + /// ``` |
| 111 | + #[must_use] |
| 112 | + #[stable(feature = "panic_hooks", since = "1.10.0")] |
| 113 | + pub fn location(&self) -> Option<&Location<'_>> { |
| 114 | + // NOTE: If this is changed to sometimes return None, |
| 115 | + // deal with that case in std::panicking::default_hook and core::panicking::panic_fmt. |
| 116 | + Some(&self.location) |
| 117 | + } |
| 118 | + |
| 119 | + /// Returns whether the panic handler is allowed to unwind the stack from |
| 120 | + /// the point where the panic occurred. |
| 121 | + /// |
| 122 | + /// This is true for most kinds of panics with the exception of panics |
| 123 | + /// caused by trying to unwind out of a `Drop` implementation or a function |
| 124 | + /// whose ABI does not support unwinding. |
| 125 | + /// |
| 126 | + /// It is safe for a panic handler to unwind even when this function returns |
| 127 | + /// false, however this will simply cause the panic handler to be called |
| 128 | + /// again. |
| 129 | + #[must_use] |
| 130 | + #[unstable(feature = "panic_can_unwind", issue = "92988")] |
| 131 | + pub fn can_unwind(&self) -> bool { |
| 132 | + self.can_unwind |
| 133 | + } |
| 134 | + |
| 135 | + #[unstable( |
| 136 | + feature = "panic_internals", |
| 137 | + reason = "internal details of the implementation of the `panic!` and related macros", |
| 138 | + issue = "none" |
| 139 | + )] |
| 140 | + #[doc(hidden)] |
| 141 | + #[inline] |
| 142 | + pub fn force_no_backtrace(&self) -> bool { |
| 143 | + self.force_no_backtrace |
| 144 | + } |
| 145 | +} |
| 146 | + |
| 147 | +#[stable(feature = "panic_hook_display", since = "1.26.0")] |
| 148 | +impl fmt::Display for PanicInfo<'_> { |
| 149 | + fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result { |
| 150 | + formatter.write_str("panicked at ")?; |
| 151 | + self.location.fmt(formatter)?; |
| 152 | + if let Some(payload) = self.payload.downcast_ref::<&'static str>() { |
| 153 | + formatter.write_str(":\n")?; |
| 154 | + formatter.write_str(payload)?; |
| 155 | + } else if let Some(payload) = self.payload.downcast_ref::<String>() { |
| 156 | + formatter.write_str(":\n")?; |
| 157 | + formatter.write_str(payload)?; |
| 158 | + } |
| 159 | + Ok(()) |
| 160 | + } |
| 161 | +} |
| 162 | + |
12 | 163 | #[doc(hidden)] |
13 | 164 | #[unstable(feature = "edition_panic", issue = "none", reason = "use panic!() instead")] |
14 | 165 | #[allow_internal_unstable(libstd_sys_internals, const_format_args, core_panic, rt)] |
@@ -43,7 +194,7 @@ pub use crate::panicking::{set_hook, take_hook}; |
43 | 194 | pub use crate::panicking::update_hook; |
44 | 195 |
|
45 | 196 | #[stable(feature = "panic_hooks", since = "1.10.0")] |
46 | | -pub use core::panic::{Location, PanicInfo}; |
| 197 | +pub use core::panic::Location; |
47 | 198 |
|
48 | 199 | #[stable(feature = "catch_unwind", since = "1.9.0")] |
49 | 200 | pub use core::panic::{AssertUnwindSafe, RefUnwindSafe, UnwindSafe}; |
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