Struct Error 

pub struct Error { /* private fields */ }

Error is the error struct returned by all foyer functions.

Display

Error can be displayed in two ways:

• Via Display: like err.to_string() or format!("{err}")

Error will be printed in a single line:

External error, context: { k1: v2, k2: v2 } => external error, source: TestError: test error

• Via Debug: like format!("{err:?}")

Error will be printed in multi lines with more details and backtraces (if captured):

External error => external error

Context:
  k1: v2
  k2: v2

Source:
  TestError: test error

Backtrace:
   0: foyer_common::error::Error::new
             at ./src/error.rs:259:38
   1: foyer_common::error::tests::test_error_format
             at ./src/error.rs:481:17
   2: foyer_common::error::tests::test_error_format::{{closure}}
             at ./src/error.rs:480:27
   ...

• For conventional struct-style Debug representation, like format!("{err:#?}"):

Error {
    kind: External,
    message: "external error",
    context: [
        (
            "k1",
            "v2",
        ),
        (
            "k2",
            "v2",
        ),
    ],
    source: Some(
        TestError(
            "test error",
        ),
    ),
    backtrace: Some(
        Backtrace [
            { fn: "foyer_common::error::Error::new", file: "./src/error.rs", line: 259 },
            { fn: "foyer_common::error::tests::test_error_format", file: "./src/error.rs", line: 481 },
            ...
        ],
    ),
}

Implementations

impl Error

pub fn new(kind: ErrorKind, message: impl Into<String>) -> Self

Create a new error.

If the error needs to carry a source error, please use with_source method.

For example“

let io_error = std::io::Error::other("an I/O error occurred");
Error::new(ErrorKind::Io, "an external error occurred").with_source(io_error);

pub fn with_context(self, key: &'static str, value: impl ToString) -> Self

Add more context in error.

pub fn with_source(self, source: impl Into<Error>) -> Self

Set source for error.

Notes

If the source has been set, we will raise a panic here.

pub fn kind(&self) -> ErrorKind

Get the error kind.

pub fn message(&self) -> &str

Get the error message.

pub fn context(&self) -> &Vec<(&'static str, String)>

Get the error context.

pub fn backtrace(&self) -> Option<&Backtrace>

Get the error backtrace.

pub fn source(&self) -> Option<&Error>

Get the error source.

pub fn downcast_ref<E>(&self) -> Option<&E>

where E: Error + Send + Sync + 'static,

Downcast the reference of the source error to a specific error type reference.

impl Error

Helper methods for Error.

pub fn raw_os_io_error(raw: i32) -> Self

Helper for creating an ErrorKind::Io error from a raw OS error code.

pub fn io_error(source: Error) -> Self

Helper for creating an ErrorKind::Io error from std::io::Error.

pub fn no_space(capacity: usize, allocated: usize, required: usize) -> Self

Helper for creating a ErrorKind::NoSpace error with context.

pub fn join(source: JoinError) -> Self

Helper for creating a ErrorKind::Join error with context.

Trait Implementations

impl Clone for Error

Cloning an Error with large message and context can be expensive.

Be careful when cloning errors in performance-critical paths.

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Error

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Error

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for Error

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.