Enum EncodeSigningDataResult 

pub enum EncodeSigningDataResult<E> {
    SighashSingleBug,
    WriteResult(Result<(), E>),
}

Result of SighashCache::legacy_encode_signing_data_to.

This type forces the caller to handle SIGHASH_SINGLE bug case.

This corner case can’t be expressed using standard Result, in a way that is both convenient and not-prone to accidental mistakes (like calling .expect("writer never fails")).

Variants

SighashSingleBug

Input data is an instance of SIGHASH_SINGLE bug

WriteResult(Result<(), E>)

Operation performed normally.

Implementations

impl<E> EncodeSigningDataResult<E>

pub fn is_sighash_single_bug(self) -> Result<bool, E>

Checks for SIGHASH_SINGLE bug returning error if the writer failed.

This method is provided for easy and correct handling of the result because SIGHASH_SINGLE bug is a special case that must not be ignored nor cause panicking. Since the data is usually written directly into a hasher which never fails, the recommended pattern to handle this is:

let cache = SighashCache::new(&tx);
if cache.legacy_encode_signing_data_to(&mut writer, input_index, &script_pubkey, sighash_u32)
        .is_sighash_single_bug()
        .expect("writer can't fail") {
    // use a hash value of "1", instead of computing the actual hash due to SIGHASH_SINGLE bug
}

pub fn map_err<E2, F>(self, f: F) -> EncodeSigningDataResult<E2>

where F: FnOnce(E) -> E2,

Maps a Result<T, E> to Result<T, F> by applying a function to a contained Err value, leaving an Ok value untouched.

Like Result::map_err.