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

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Formats the value using the given formatter. Read more

👎 Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

👎 Deprecated since 1.42.0:

use the Display impl or to_string()

The lower-level source of this error, if any. Read more

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

Returns a stack backtrace, if available, of where this error occurred. Read more

Performs the conversion.

Performs the conversion.

Performs the conversion.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

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

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

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

Uses borrowed data to replace owned data, usually by cloning. Read more

Converts the given value to a String. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.