Struct Derivation 

pub struct Derivation {
    pub op: Op,
    pub source: RawContentId,
    pub span: Span,
    pub elided: RawContentId,
    pub root: ContentId,
}

What was done, to which material, on whose authority.

This is the hashed body of a unit. Change the source, the span, the operation or the root and you get a different ContentId — which is the property the whole kernel rests on and is asserted directly by tests/addressing.rs.

Fields

op: Op

What was done to the material.

source: RawContentId

The source byte string this derivation is over.

span: Span

Which byte range of source.

elided: RawContentId

The material that range covers.

Functionally redundant given source and span — and that is the point. It is the claim being checked: re-derivation recomputes the hash of the addressed bytes and compares it to this field. A check with nothing recorded to compare against is not a check, and the earlier revision shipped the word rederive without one.

root: ContentId

The crate::RootEvent that caused this derivation.

Implementations

impl Derivation

pub fn over(op: Op, source: &[u8], span: Span, root: ContentId) -> Option<Self>

Address a derivation over source at span, rooted in root.

Returns None when the span does not lie within source — an address that does not resolve is not an address, so it cannot be built.

pub fn id(&self) -> Result<ContentId, ContentError>

This derivation’s address — and therefore its unit’s.

Errors

Propagates an encoding failure from the canonical form.

Trait Implementations

impl Clone for Derivation

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl ContentAddressable for Derivation

fn canonical_form(&self) -> Result<Vec<u8>, ContentError>

Produce the deterministic byte representation of this value.

fn content_id(&self) -> Result<ContentId, ContentError>

Compute this value’s ContentId.

fn verify(&self, expected: &ContentId) -> Result<bool, ContentError>

Check whether this value’s content id matches an expected id.

fn ensure_content_id(&self, expected: &ContentId) -> Result<(), ContentError>

Verify, returning an error on mismatch instead of Ok(false).

fn from_canonical_form(bytes: &[u8]) -> Result<Self, ContentError>

where Self: Sized + DeserializeOwned,

Checked ingress: decode a value from its canonical form, proving the bytes reproduce it — a checked partial inverse of canonical_form.

impl Copy for Derivation

impl Debug for Derivation

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Derivation

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for Derivation

impl Hash for Derivation

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for Derivation

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

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

Restrict a value to a certain range.

impl PartialEq for Derivation

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

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialOrd for Derivation

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for Derivation

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Derivation