Enum hdk::prelude::ChainTopOrdering

pub enum ChainTopOrdering {
    Relaxed,
    Strict,
}

Variants

Relaxed

Relaxed chain top ordering REWRITES ACTIONS INLINE during a flush of the source chain to sit on top of the current chain top. The “as at” of the zome call initial state is completely ignored. This may be significantly more efficient if you are CERTAIN that none of your zome or validation logic is order dependent. Examples include simple chat messages or tweets. Note however that even chat messages and tweets may have subtle order dependencies, such as if a cap grant was written or revoked that would have invalidated the zome call that wrote data after the revocation, etc. The efficiency of relaxed ordering comes from simply rehashing and signing actions on the new chain top during flush, avoiding the overhead of the client, websockets, zome call instance, wasm execution, validation, etc. that would result from handling a HeadMoved error via an external driver.

Strict

The default Strict ordering is the default for a very good reason. Writes normally compare the chain head from the start of a zome call against the time a write transaction is flushed from the source chain. This is REQUIRED for data integrity if any zome or validation logic depends on the ordering of data in a chain. This order dependence could be obvious such as an explicit reference or dependency. It could be very subtle such as checking for the existence or absence of some data. If you are unsure whether your data is order dependent you should err on the side of caution and handle HeadMoved errors on the client of the zome call and restart the zome call from the start.

Trait Implementations

impl Clone for ChainTopOrdering

fn clone(&self) -> ChainTopOrdering

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ChainTopOrdering

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

Formats the value using the given formatter.

impl Default for ChainTopOrdering

fn default() -> ChainTopOrdering

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ChainTopOrdering

fn deserialize<__D>(
    __deserializer: __D
) -> Result<ChainTopOrdering, <__D as Deserializer<'de>>::Error>where
    __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq<ChainTopOrdering> for ChainTopOrdering

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

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

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for ChainTopOrdering

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.

impl Copy for ChainTopOrdering

impl StructuralPartialEq for ChainTopOrdering