Enum hdk::prelude::ChainQueryFilterRange [−][src]
pub enum ChainQueryFilterRange {
Unbounded,
HeaderSeqRange(u32, u32),
HeaderHashRange(HoloHash<Header>, HoloHash<Header>),
HeaderHashTerminated(HoloHash<Header>, u32),
}
Expand description
Defines several ways that queries can be restricted to a range. Notably hash bounded ranges disambiguate forks whereas sequence indexes do not as the same position can be found in many forks. The reason that this does NOT use native rust range traits is that the hash bounded queries MUST be inclusive otherwise the integrity and fork disambiguation logic is impossible. An exclusive range bound that does not include the final header tells us nothing about which fork to select between N forks of equal length that proceed it. With an inclusive hash bounded range the final header always points unambiguously at the “correct” fork that the range is over. Start hashes are not needed to provide this property so ranges can be hash terminated with a length of preceeding elements to return only. Technically the seq bounded ranges do not imply any fork disambiguation and so could be a range but for simplicity we left the API symmetrical in boundedness across all enum variants. @TODO It may be possible to provide/implement RangeBounds in the case that a full sequence of elements/headers is provided but it would need to be handled as inclusive first, to enforce the integrity of the query, then the exclusiveness achieved by simply removing the final element after the fact.
Variants
Unbounded
Do NOT apply any range filtering for this query.
HeaderSeqRange(u32, u32)
A range over source chain sequence numbers. This is ambiguous over forking histories and so should NOT be used in validation logic. Inclusive start, inclusive end.
HeaderHashRange(HoloHash<Header>, HoloHash<Header>)
A range over source chain header hashes. This CAN be used in validation logic as forks are disambiguated. Inclusive start and end (unlike std::ops::Range).
HeaderHashTerminated(HoloHash<Header>, u32)
The terminating header hash and N preceeding elements.
N = 0 returns only the element with this HeaderHash
.
This CAN be used in validation logic as forks are not possible when
“looking up” towards genesis from some HeaderHash
.
Trait Implementations
Returns the “default value” for a type. Read more
pub fn deserialize<__D>(
__deserializer: __D
) -> Result<ChainQueryFilterRange, <__D as Deserializer<'de>>::Error> where
__D: Deserializer<'de>,
pub fn deserialize<__D>(
__deserializer: __D
) -> Result<ChainQueryFilterRange, <__D as Deserializer<'de>>::Error> where
__D: Deserializer<'de>,
Deserialize this value from the given Serde deserializer. Read more
This method tests for self
and other
values to be equal, and is used
by ==
. Read more
This method tests for !=
.
pub fn serialize<__S>(
&self,
__serializer: __S
) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error> where
__S: Serializer,
pub fn serialize<__S>(
&self,
__serializer: __S
) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error> where
__S: Serializer,
Serialize this value into the given Serde serializer. Read more
Auto Trait Implementations
impl RefUnwindSafe for ChainQueryFilterRange
impl Send for ChainQueryFilterRange
impl Sync for ChainQueryFilterRange
impl Unpin for ChainQueryFilterRange
impl UnwindSafe for ChainQueryFilterRange
Blanket Implementations
Mutably borrows from an owned value. Read more
fn instrument(self, span: Span) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn instrument(self, span: Span) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn in_current_span(self) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn in_current_span(self) -> Instrumented<Self>ⓘNotable traits for Instrumented<T>impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
impl<T> Future for Instrumented<T> where
T: Future, type Output = <T as Future>::Output;
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
where
S: Into<Dispatch>,
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
where
S: Into<Dispatch>,
impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
Attaches the provided Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
fn with_current_subscriber(self) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
fn with_current_subscriber(self) -> WithDispatch<Self>ⓘNotable traits for WithDispatch<T>impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
impl<T> Future for WithDispatch<T> where
T: Future, type Output = <T as Future>::Output;
Attaches the current default Subscriber
to this type, returning a
WithDispatch
wrapper. Read more