Trait CompareAndSwap 

pub trait CompareAndSwap {
    type Error: Debug;

    // Required methods
    fn insert_if_absent(
        &self,
        key: &[u8],
        value: &[u8],
    ) -> Result<bool, Self::Error>;
    fn compare_and_set(
        &self,
        key: &[u8],
        expected: &[u8],
        new_value: &[u8],
    ) -> Result<bool, Self::Error>;
    fn delete_if_match(
        &self,
        key: &[u8],
        expected: &[u8],
    ) -> Result<bool, Self::Error>;
}

Compare-and-swap trait for storage backends

This trait abstracts the CAS operation for different storage implementations. SochDB’s storage layer should implement this for durable claims.

Required Associated Types

type Error: Debug

Type of error returned

Required Methods

fn insert_if_absent( &self, key: &[u8], value: &[u8], ) -> Result<bool, Self::Error>

Insert a key-value pair only if the key doesn’t exist

Returns Ok(true) if inserted, Ok(false) if key exists, Err on failure.

fn compare_and_set( &self, key: &[u8], expected: &[u8], new_value: &[u8], ) -> Result<bool, Self::Error>

Update a value only if the current value matches expected

Returns Ok(true) if updated, Ok(false) if mismatch, Err on failure.

fn delete_if_match( &self, key: &[u8], expected: &[u8], ) -> Result<bool, Self::Error>

Delete a key only if the current value matches expected

Returns Ok(true) if deleted, Ok(false) if mismatch, Err on failure.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors