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.

Implementors