Struct ring::error::Unspecified

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pub struct Unspecified;
Expand description

An error with absolutely no details.

ring uses this unit type as the error type in most of its results because (a) usually the specific reasons for a failure are obvious or are not useful to know, and/or (b) providing more details about a failure might provide a dangerous side channel, and/or (c) it greatly simplifies the error handling logic.

Result<T, ring::error::Unspecified> is mostly equivalent to Result<T, ()>. However, ring::error::Unspecified implements std::error::Error and users of ring can implement From<ring::error::Unspecified> to map this to their own error types, as described in “Error Handling” in the Rust Book:

use ring::rand::{self, SecureRandom};

enum Error {
    CryptoError,

    IOError(std::io::Error),
    // [...]
}

impl From<ring::error::Unspecified> for Error {
    fn from(_: ring::error::Unspecified) -> Self { Error::CryptoError }
}

fn eight_random_bytes() -> Result<[u8; 8], Error> {
    let rng = rand::SystemRandom::new();
    let mut bytes = [0; 8];

    // The `From<ring::error::Unspecified>` implementation above makes this
    // equivalent to
    // `rng.fill(&mut bytes).map_err(|_| Error::CryptoError)?`.
    rng.fill(&mut bytes)?;

    Ok(bytes)
}

assert!(eight_random_bytes().is_ok());

Experience with using and implementing other crypto libraries like has shown that sophisticated error reporting facilities often cause significant bugs themselves, both within the crypto library and within users of the crypto library. This approach attempts to minimize complexity in the hopes of avoiding such problems. In some cases, this approach may be too extreme, and it may be important for an operation to provide some details about the cause of a failure. Users of ring are encouraged to report such cases so that they can be addressed individually.

Trait Implementations§

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impl Clone for Unspecified

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fn clone(&self) -> Unspecified

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for Unspecified

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

Formats the value using the given formatter. Read more
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impl Display for Unspecified

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

Formats the value using the given formatter. Read more
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impl Error for Unspecified

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

The lower-level source of this error, if any. Read more
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fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()
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fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
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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. Read more
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impl From<EndOfInput> for Unspecified

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fn from(_: EndOfInput) -> Self

Converts to this type from the input type.
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impl From<KeyRejected> for Unspecified

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fn from(_: KeyRejected) -> Self

Converts to this type from the input type.
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impl From<TryFromSliceError> for Unspecified

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fn from(_: TryFromSliceError) -> Self

Converts to this type from the input type.
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impl PartialEq for Unspecified

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fn eq(&self, other: &Unspecified) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl Copy for Unspecified

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impl StructuralPartialEq for Unspecified

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Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T> ToString for T
where T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.