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| Original file line number | Diff line number | Diff line change |
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| @@ -1,199 +1,47 @@ | ||
| #![allow(missing_docs)] | ||
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| use core::fmt::{Debug, Display}; | ||
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| /// `Error` is a trait representing the basic expectations for error values, | ||
| /// i.e., values of type `E` in `Result<T, E>`. Errors must describe | ||
| /// themselves through the `Display` and `Debug` traits, and may provide | ||
| /// cause chain information: | ||
| /// | ||
| /// The [`source`] method is generally used when errors cross "abstraction | ||
| /// boundaries". If one module must report an error that is caused by an error | ||
| /// from a lower-level module, it can allow access to that error via the | ||
| /// [`source`] method. This makes it possible for the high-level module to | ||
| /// provide its own errors while also revealing some of the implementation for | ||
| /// debugging via [`source`] chains. | ||
| /// | ||
| /// [`source`]: trait.Error.html#method.source | ||
| pub trait Error: Debug + Display { | ||
| /// **This method is soft-deprecated.** | ||
| /// | ||
| /// Although using it won’t cause compilation warning, | ||
| /// new code should use `Display` instead | ||
| /// and new `impl`s can omit it. | ||
| /// | ||
| /// To obtain error description as a string, use `to_string()`. | ||
| /// | ||
| /// # Examples | ||
| /// | ||
| /// ``` | ||
| /// match "xc".parse::<u32>() { | ||
| /// Err(e) => { | ||
| /// // Print `e` itself, not `e.description()`. | ||
| /// println!("Error: {}", e); | ||
| /// } | ||
| /// _ => println!("No error"), | ||
| /// } | ||
| /// ``` | ||
| fn description(&self) -> &str { | ||
| "description() is deprecated; use Display" | ||
| } | ||
|
|
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| /// The lower-level cause of this error, if any. | ||
| /// | ||
| /// # Examples | ||
| /// | ||
| /// ``` | ||
| /// use snafu::Error; | ||
| /// use core::fmt; | ||
| /// | ||
| /// #[derive(Debug)] | ||
| /// struct SuperError { | ||
| /// side: SuperErrorSideKick, | ||
| /// } | ||
| /// | ||
| /// impl fmt::Display for SuperError { | ||
| /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
| /// write!(f, "SuperError is here!") | ||
| /// } | ||
| /// } | ||
| /// | ||
| /// impl Error for SuperError { | ||
| /// fn description(&self) -> &str { | ||
| /// "I'm the superhero of errors" | ||
| /// } | ||
| /// | ||
| /// fn cause(&self) -> Option<&dyn Error> { | ||
| /// Some(&self.side) | ||
| /// } | ||
| /// } | ||
| /// | ||
| /// #[derive(Debug)] | ||
| /// struct SuperErrorSideKick; | ||
| /// | ||
| /// impl fmt::Display for SuperErrorSideKick { | ||
| /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
| /// write!(f, "SuperErrorSideKick is here!") | ||
| /// } | ||
| /// } | ||
| /// | ||
| /// impl Error for SuperErrorSideKick { | ||
| /// fn description(&self) -> &str { | ||
| /// "I'm SuperError side kick" | ||
| /// } | ||
| /// } | ||
| /// | ||
| /// fn get_super_error() -> Result<(), SuperError> { | ||
| /// Err(SuperError { side: SuperErrorSideKick }) | ||
| /// } | ||
| /// | ||
| /// fn main() { | ||
| /// match get_super_error() { | ||
| /// Err(e) => { | ||
| /// println!("Error: {}", e.description()); | ||
| /// println!("Caused by: {}", e.cause().unwrap()); | ||
| /// } | ||
| /// _ => println!("No error"), | ||
| /// } | ||
| /// } | ||
| /// ``` | ||
| fn cause(&self) -> Option<&dyn Error> { | ||
| fn cause(&self) -> Option<&Error> { | ||
| self.source() | ||
| } | ||
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|
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| /// The lower-level source of this error, if any. | ||
| /// | ||
| /// # Examples | ||
| /// | ||
| /// ``` | ||
| /// use snafu::Error; | ||
| /// use core::fmt; | ||
| /// | ||
| /// #[derive(Debug)] | ||
| /// struct SuperError { | ||
| /// side: SuperErrorSideKick, | ||
| /// } | ||
| /// | ||
| /// impl fmt::Display for SuperError { | ||
| /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
| /// write!(f, "SuperError is here!") | ||
| /// } | ||
| /// } | ||
| /// | ||
| /// impl Error for SuperError { | ||
| /// fn description(&self) -> &str { | ||
| /// "I'm the superhero of errors" | ||
| /// } | ||
| /// | ||
| /// fn source(&self) -> Option<&(dyn Error + 'static)> { | ||
| /// Some(&self.side) | ||
| /// } | ||
| /// } | ||
| /// | ||
| /// #[derive(Debug)] | ||
| /// struct SuperErrorSideKick; | ||
| /// | ||
| /// impl fmt::Display for SuperErrorSideKick { | ||
| /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
| /// write!(f, "SuperErrorSideKick is here!") | ||
| /// } | ||
| /// } | ||
| /// | ||
| /// impl Error for SuperErrorSideKick { | ||
| /// fn description(&self) -> &str { | ||
| /// "I'm SuperError side kick" | ||
| /// } | ||
| /// } | ||
| /// | ||
| /// fn get_super_error() -> Result<(), SuperError> { | ||
| /// Err(SuperError { side: SuperErrorSideKick }) | ||
| /// } | ||
| /// | ||
| /// fn main() { | ||
| /// match get_super_error() { | ||
| /// Err(e) => { | ||
| /// println!("Error: {}", e.description()); | ||
| /// println!("Caused by: {}", e.source().unwrap()); | ||
| /// } | ||
| /// _ => println!("No error"), | ||
| /// } | ||
| /// } | ||
| /// ``` | ||
| fn source(&self) -> Option<&(dyn Error + 'static)> { | ||
| fn source(&self) -> Option<&(Error + 'static)> { | ||
| None | ||
| } | ||
| } | ||
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| impl Error for core::str::ParseBoolError { | ||
| fn description(&self) -> &str { | ||
| "failed to parse bool" | ||
| } | ||
| } | ||
| impl Error for core::str::Utf8Error { | ||
| fn description(&self) -> &str { | ||
| "invalid utf-8: corrupt contents" | ||
| } | ||
| } | ||
| impl Error for core::num::ParseIntError {} | ||
| impl Error for core::num::TryFromIntError {} | ||
| impl Error for core::array::TryFromSliceError {} | ||
| impl Error for core::num::ParseFloatError {} | ||
| impl Error for core::fmt::Error { | ||
| fn description(&self) -> &str { | ||
| "an error occurred when formatting an argument" | ||
| } | ||
| } | ||
| impl Error for core::cell::BorrowError { | ||
| fn description(&self) -> &str { | ||
| "already mutably borrowed" | ||
| } | ||
| } | ||
| impl Error for core::cell::BorrowMutError { | ||
| fn description(&self) -> &str { | ||
| "already borrowed" | ||
| macro_rules! impl_error { | ||
| ($($e:path),*) => { | ||
| $( | ||
| impl Error for $e {} | ||
| )* | ||
| } | ||
| } | ||
| impl Error for core::char::CharTryFromError { | ||
| fn description(&self) -> &str { | ||
| "converted integer out of range for `char`" | ||
| } | ||
| } | ||
| impl Error for core::char::ParseCharError {} | ||
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| // All errors supported by our minimum suported Rust version can be supported by | ||
| // default. | ||
| impl_error![ | ||
| core::str::ParseBoolError, // 1.0 | ||
| core::str::Utf8Error, // 1.0 | ||
| core::num::ParseIntError, // 1.0 | ||
| core::num::ParseFloatError, // 1.0 | ||
| core::char::DecodeUtf16Error, // 1.9 | ||
| core::fmt::Error, // 1.11 | ||
| core::cell::BorrowMutError, // 1.13 | ||
| core::cell::BorrowError // 1.13 | ||
| ]; | ||
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| #[cfg(feature = "rust_1_30")] | ||
| impl_error![core::char::ParseCharError]; // 1.20 | ||
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| // We can gate these together with std futures. | ||
| #[cfg(feature = "unstable-futures")] | ||
| impl_error![ | ||
| core::num::TryFromIntError, // 1.34 | ||
| core::array::TryFromSliceError, // 1.34 | ||
| core::char::CharTryFromError // 1.34 | ||
| ]; |