Trait crdts::CmRDT

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pub trait CmRDT {
    type Op;
    type Validation: Error;

    // Required methods
    fn validate_op(&self, op: &Self::Op) -> Result<(), Self::Validation>;
    fn apply(&mut self, op: Self::Op);
}

Expand description

Operation based CRDT’s replicate by transmitting each operation.

Required Associated Types§

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type Op

Op defines a mutation to the CRDT. As long as Op’s from one actor are replayed in exactly the same order they were generated by that actor, the CRDT will converge. In other words, we must have a total ordering on each actors operations, while requiring only a partial order over all ops. E.g.

Actor A produces ops A1, A2
Actor B produces ops B1, B2

the only valid orderings are:

A1 < A2 < B1 < B2
A1 < B1 < A2 < B2
B1 < A1 < A2 < B2
A1 < B1 < B2 < A2
B1 < A1 < B2 < A2
B1 < B2 < A1 < A2

Applying ops in any of the valid orders will converge to the same CRDT state

Op’s must be idempotent, meaning any Op may be applied more than once.

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type Validation: Error

The validation error returned by validate_op.

Required Methods§

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fn validate_op(&self, op: &Self::Op) -> Result<(), Self::Validation>

Some CRDT’s have stricter requirements on how they must be used. To avoid violating these requirements, CRDT’s provide an interface to optionally validate op’s before they are applied.

An Ok(()) response signals that this operation is safe to apply. Otherwise a structured error is returned to help you determine what is wrong with the operation

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