1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
use crate::HashType;
use holochain_serialized_bytes::prelude::*;
/// Any implementor of HashableContent may be used in a HoloHashed to pair
/// data with its HoloHash representation. It also has an associated HashType.
pub trait HashableContent: Sized {
/// The HashType which this content will be hashed to
type HashType: HashType;
/// The HashType which this content will be hashed to
fn hash_type(&self) -> Self::HashType;
/// Return a subset of the content, either as SerializedBytes "content",
/// which will be used to compute the hash, or as an already precomputed
/// hash which will be used directly
fn hashable_content(&self) -> HashableContentBytes;
}
/// HashableContent can be expressed as "content", or "prehashed", which affects
/// how a HoloHashed type will be constructed from it.
pub enum HashableContentBytes {
/// Denotes that the hash should be computed for the given data
Content(SerializedBytes),
/// Denotes that the given bytes already constitute a valid HoloHash
Prehashed39(Vec<u8>),
}
/// A default HashableContent implementation, suitable for content which
/// is already TryInto<SerializedBytes>, and uses a PrimitiveHashType
#[macro_export]
macro_rules! impl_hashable_content {
($n: ident, $t: ident) => {
impl HashableContent for $n {
type HashType = holo_hash::hash_type::$t;
fn hash_type(&self) -> Self::HashType {
use holo_hash::PrimitiveHashType;
holo_hash::hash_type::$t::new()
}
fn hashable_content(&self) -> $crate::HashableContentBytes {
$crate::HashableContentBytes::Content(
self.try_into()
.expect("Could not serialize HashableContent"),
)
}
}
};
}