pub trait ResultExt: Sized {
type Success;
type Error: Fail;
// Required method
fn chain_inspect_err<ErrorKindT: ChainErrorKind>(
self,
map: impl FnOnce(&mut Self::Error) -> ErrorKindT,
) -> Result<Self::Success, ErrorKindT::Error>;
// Provided method
fn chain_err<ErrorKindT: ChainErrorKind>(
self,
map: impl FnOnce() -> ErrorKindT,
) -> Result<Self::Success, ErrorKindT::Error> { ... }
}Expand description
Extension trait which adds the family of .chain_err methods to Result objects.
Required Associated Types§
Required Methods§
Sourcefn chain_inspect_err<ErrorKindT: ChainErrorKind>(
self,
map: impl FnOnce(&mut Self::Error) -> ErrorKindT,
) -> Result<Self::Success, ErrorKindT::Error>
fn chain_inspect_err<ErrorKindT: ChainErrorKind>( self, map: impl FnOnce(&mut Self::Error) -> ErrorKindT, ) -> Result<Self::Success, ErrorKindT::Error>
Like chain_err, but the callback is given an opportunity to inspect the original error.
Provided Methods§
Sourcefn chain_err<ErrorKindT: ChainErrorKind>(
self,
map: impl FnOnce() -> ErrorKindT,
) -> Result<Self::Success, ErrorKindT::Error>
fn chain_err<ErrorKindT: ChainErrorKind>( self, map: impl FnOnce() -> ErrorKindT, ) -> Result<Self::Success, ErrorKindT::Error>
Replace the error in a Result with a new error built from map’s ErrorKind output.
The original error is stored as the cause/source of the new one.
Examples found in repository?
examples/main.rs (line 71)
69 fn load(wad: &Path, metadata: &Path) -> Result<()> {
70 // `chain_err` stashes the original error as the `cause` of a new error.
71 let wad_file = File::open(wad).chain_err(|| ErrorKind::WadIo(wad.to_owned()))?;
72
73 let mut metadata_content = String::new();
74
75 // `chain_inspect_err` stashes the original error as the `cause` of the new
76 // error, but it first allows the callback to inspect it.
77 let metadata_file = File::open(metadata)
78 .and_then(|mut file| file.read_to_string(&mut metadata_content))
79 .chain_inspect_err(|_io_error| ErrorKind::MetadataIo(metadata.to_owned()))?;
80
81 validate_metadata(metadata, &metadata_content)?;
82
83 Ok(())
84 }Dyn Compatibility§
This trait is not dyn compatible.
In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.