Struct ArcError 

pub struct ArcError(/* private fields */);

An error more than one owner can keep.

BoxError belongs to one owner: passing it on moves it. Some errors are held by several values at once — a terminal connection error that every stream on that connection reports, say — and their cause is often not Clone. This shares one cause between those owners.

It displays as the error it shares and downcasts to it, so a message reads the same either way. Its source is that error, which is one step a chain would not have without the sharing: that is what lets a cause be recovered by type after context is wrapped around it. A caller that would rather not show the step — an error that stores its cause this way but wants its own chain to lead straight to the failure — can use ArcError::as_error.

Adding context produces a new value; what other owners of the same cause already see never changes.

Implementations

impl ArcError

pub fn new<E>(error: E) -> ArcError

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

Share a concrete error. The error moves straight into the shared allocation.

pub fn from_static_str(message: &'static str) -> ArcError

Share a static message. One allocation for the sharing, none for the message.

pub fn from_box_error(error: Box<dyn Error + Sync + Send>) -> ArcError

Share an error that is already boxed. The box’s value moves into the shared allocation.

pub fn as_error(&self) -> &(dyn Error + 'static)

The error this shares, as an error: what a chain should continue with when the sharing itself is storage rather than a step worth showing.

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

where T: Error + 'static,

The concrete error inside, if it is a T.

pub fn context<M>(self, value: M) -> ArcError

where M: Debug + Display + Send + Sync + 'static,

Wrap the error in a context, as ErrorExt::context does.

pub fn context_field<M>(self, key: &'static str, value: M) -> ArcError

where M: Debug + Display + Send + Sync + 'static,

Wrap the error in a keyed context, as ErrorExt::context_field does.

pub fn context_str_field<M>(self, key: &'static str, value: M) -> ArcError

where M: Into<String>,

Wrap the error in a keyed context from a string-like value, for a value that cannot be borrowed for the error’s lifetime.

pub fn context_hex<M>(self, value: M) -> ArcError

where M: Debug + Send + Sync + 'static,

Wrap the error in a context, using fmt::LowerHex as fmt::Debug and fmt::Display.

pub fn context_debug<M>(self, value: M) -> ArcError

where M: Debug + Send + Sync + 'static,

Wrap the error in a context, using fmt::Debug as fmt::Display.

pub fn context_hex_field<M>(self, key: &'static str, value: M) -> ArcError

where M: Debug + Send + Sync + 'static,

Wrap the error in a keyed context, using fmt::LowerHex as fmt::Debug and fmt::Display.

pub fn context_debug_field<M>(self, key: &'static str, value: M) -> ArcError

where M: Debug + Send + Sync + 'static,

Wrap the error in a keyed context, using fmt::Debug as fmt::Display.

pub fn with_context<C, F>(self, cb: F) -> ArcError

where C: Debug + Display + Send + Sync + 'static, F: FnOnce() -> C,

Wrap the error with a context the caller builds only now.

pub fn with_context_hex<C, F>(self, cb: F) -> ArcError

where C: Debug + Send + Sync + 'static, F: FnOnce() -> C,

Wrap the error with a context the caller builds only now, using fmt::LowerHex.

pub fn with_context_debug<C, F>(self, cb: F) -> ArcError

where C: Debug + Send + Sync + 'static, F: FnOnce() -> C,

Wrap the error with a context the caller builds only now, using fmt::Debug.

pub fn with_context_field<C, F>(self, key: &'static str, cb: F) -> ArcError

where C: Debug + Display + Send + Sync + 'static, F: FnOnce() -> C,

Wrap the error with a keyed context the caller builds only now.

pub fn with_context_str_field<C, F>(self, key: &'static str, cb: F) -> ArcError

where C: Into<String>, F: FnOnce() -> C,

Wrap the error with a keyed string-like context the caller builds only now.

pub fn with_context_hex_field<C, F>(self, key: &'static str, cb: F) -> ArcError

where C: Debug + Send + Sync + 'static, F: FnOnce() -> C,

Wrap the error with a keyed context the caller builds only now, using fmt::LowerHex.

pub fn with_context_debug_field<C, F>( self, key: &'static str, cb: F, ) -> ArcError

where C: Debug + Send + Sync + 'static, F: FnOnce() -> C,

Wrap the error with a keyed context the caller builds only now, using fmt::Debug.

Trait Implementations

impl Clone for ArcError

fn clone(&self) -> ArcError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ArcError

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

Formats the value using the given formatter.

impl Display for ArcError

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

Formats the value using the given formatter.

impl Error for ArcError

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

The error this shares. A chain through an ArcError reaches the concrete cause and can be downcast to it, which is what makes a cause survive being wrapped in context; the wrapper’s own fmt::Display is that cause’s, so it reads the same either way.

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.

impl From<Box<dyn Error + Sync + Send>> for ArcError

fn from(error: Box<dyn Error + Sync + Send>) -> ArcError

Converts to this type from the input type.