Trait tari_storage::KeyValueStore

pub trait KeyValueStore<K, V> {
    fn insert(&self, key: K, value: V) -> Result<(), KeyValStoreError>;
    fn get(&self, key: &K) -> Result<Option<V>, KeyValStoreError>;
    fn size(&self) -> Result<usize, KeyValStoreError>;
    fn for_each<F>(&self, f: F) -> Result<(), KeyValStoreError>
    where
        Self: Sized,
        F: FnMut(Result<(K, V), KeyValStoreError>) -> IterationResult;
    fn exists(&self, key: &K) -> Result<bool, KeyValStoreError>;
    fn delete(&self, key: &K) -> Result<(), KeyValStoreError>;

    fn for_each_ok<F>(&self, f: F) -> Result<(), KeyValStoreError>
    where
        Self: Sized,
        F: FnMut((K, V)) -> IterationResult,
    { ... }
    fn filter<F>(&self, predicate: F) -> Result<Vec<(K, V)>, KeyValStoreError>
    where
        Self: Sized,
        F: FnMut(&(K, V)) -> bool,
    { ... }
    fn filter_take<F>(
        &self, 
        n: usize, 
        predicate: F
    ) -> Result<Vec<(K, V)>, KeyValStoreError>
    where
        Self: Sized,
        F: FnMut(&(K, V)) -> bool,
    { ... }
}

General CRUD behaviour of Key-value store implementations.

Required methods

fn insert(&self, key: K, value: V) -> Result<(), KeyValStoreError>

Inserts a key-value pair into the key-value database.

fn get(&self, key: &K) -> Result<Option<V>, KeyValStoreError>

Get the value corresponding to the provided key from the key-value database.

fn size(&self) -> Result<usize, KeyValStoreError>

Returns the total number of entries recorded in the key-value database.

fn for_each<F>(&self, f: F) -> Result<(), KeyValStoreError> where
    Self: Sized,
    F: FnMut(Result<(K, V), KeyValStoreError>) -> IterationResult, 

Execute function f for each value in the database.

f is a closure of form |pair: Result<(K,V), KeyValStoreError>| -> IterationResult. If IterationResult::Break is returned the closure will not be called again and for_each will return. You will usually need to include type inference to let Rust know which type to deserialise to:

   let res = db.for_each::<Key, Val, _>(|pair| {
       let (key, val) = pair.unwrap();
       //.. do stuff with key and val..
   });

fn exists(&self, key: &K) -> Result<bool, KeyValStoreError>

Checks whether the provided key exists in the key-value database.

fn delete(&self, key: &K) -> Result<(), KeyValStoreError>

Delete a key-pair record associated with the provided key from the key-pair database.

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Provided methods

fn for_each_ok<F>(&self, f: F) -> Result<(), KeyValStoreError> where
    Self: Sized,
    F: FnMut((K, V)) -> IterationResult, 

Execute function f for each value in the database. Any errors are filtered out. This is useful for any caller which could not do any better with an error than filtering it out.

f is a closure of form |pair: (K,V)| -> (). You will usually need to include type inference to let Rust know which type to deserialise to:

   let res = db.for_each_ok::<Key, Val, _>(|(key, val)| {
       //.. do stuff with key and val..
   });

fn filter<F>(&self, predicate: F) -> Result<Vec<(K, V)>, KeyValStoreError> where
    Self: Sized,
    F: FnMut(&(K, V)) -> bool, 

Return a Vec<(K, V)> filtered by the predicate.

Bare in mind that this is not an Iterator and filter will fetch data eagerly.

fn filter_take<F>(
    &self,
    n: usize,
    predicate: F
) -> Result<Vec<(K, V)>, KeyValStoreError> where
    Self: Sized,
    F: FnMut(&(K, V)) -> bool, 

Return a Vec<(K, V)> filtered by the predicate. At most n pairs are returned.

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Implementors

impl<K, V> KeyValueStore<K, V> for LMDBWrapper<K, V> where
    K: AsLmdbBytes + DeserializeOwned,
    V: Serialize + DeserializeOwned, 

fn insert(&self, key: K, value: V) -> Result<(), KeyValStoreError>

Inserts a key-value pair into the key-value database.

fn get(&self, key: &K) -> Result<Option<V>, KeyValStoreError> where
    V: DeserializeOwned, 

Get the value corresponding to the provided key from the key-value database.

fn size(&self) -> Result<usize, KeyValStoreError>

Returns the total number of entries recorded in the key-value database.

fn for_each<F>(&self, f: F) -> Result<(), KeyValStoreError> where
    F: FnMut(Result<(K, V), KeyValStoreError>) -> IterationResult, 

Iterate over all the stored records and execute the function f for each pair in the key-value database.

fn exists(&self, key: &K) -> Result<bool, KeyValStoreError>

Checks whether a record exist in the key-value database that corresponds to the provided key.

fn delete(&self, key: &K) -> Result<(), KeyValStoreError>

Remove the record from the key-value database that corresponds with the provided key.

impl<K: Clone + Eq + Hash, V: Clone> KeyValueStore<K, V> for HashmapDatabase<K, V>

fn insert(&self, key: K, value: V) -> Result<(), KeyValStoreError>

Inserts a key-value pair into the key-value database.

fn get(&self, key: &K) -> Result<Option<V>, KeyValStoreError>

Get the value corresponding to the provided key from the key-value database.

fn size(&self) -> Result<usize, KeyValStoreError>

Returns the total number of entries recorded in the key-value database.

fn for_each<F>(&self, f: F) -> Result<(), KeyValStoreError> where
    F: FnMut(Result<(K, V), KeyValStoreError>) -> IterationResult, 

Iterate over all the stored records and execute the function f for each pair in the key-value database.

fn exists(&self, key: &K) -> Result<bool, KeyValStoreError>

Checks whether a record exist in the key-value database that corresponds to the provided key.

fn delete(&self, key: &K) -> Result<(), KeyValStoreError>

Remove the record from the key-value database that corresponds with the provided key.

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