Trait log::kv::source::Source

pub trait Source {
    fn visit<'kvs>(
        &'kvs self, 
        visitor: &mut dyn Visitor<'kvs>
    ) -> Result<(), Error>;

    fn get<'v>(&'v self, key: Key<'_>) -> Option<Value<'v>> { ... }
    fn count(&self) -> usize { ... }
}

A source of key-value pairs.

The source may be a single pair, a set of pairs, or a filter over a set of pairs. Use the Visitor trait to inspect the structured data in a source.

Required methods

fn visit<'kvs>(&'kvs self, visitor: &mut dyn Visitor<'kvs>) -> Result<(), Error>

Visit key-value pairs.

A source doesn’t have to guarantee any ordering or uniqueness of key-value pairs. If the given visitor returns an error then the source may early-return with it, even if there are more key-value pairs.

Implementation notes

A source should yield the same key-value pairs to a subsequent visitor unless that visitor itself fails.

Provided methods

fn get<'v>(&'v self, key: Key<'_>) -> Option<Value<'v>>

Get the value for a given key.

If the key appears multiple times in the source then which key is returned is implementation specific.

Implementation notes

A source that can provide a more efficient implementation of this method should override it.

fn count(&self) -> usize

Count the number of key-value pairs that can be visited.

Implementation notes

A source that knows the number of key-value pairs upfront may provide a more efficient implementation.

A subsequent call to visit should yield the same number of key-value pairs to the visitor, unless that visitor fails part way through.

Implementations on Foreign Types

impl<'a, T> Source for &'a T where
    T: Source + ?Sized, 

fn visit<'kvs>(&'kvs self, visitor: &mut dyn Visitor<'kvs>) -> Result<(), Error>

fn get<'v>(&'v self, key: Key<'_>) -> Option<Value<'v>>

fn count(&self) -> usize

impl<K, V> Source for (K, V) where
    K: ToKey,
    V: ToValue, 

fn visit<'kvs>(&'kvs self, visitor: &mut dyn Visitor<'kvs>) -> Result<(), Error>

fn get<'v>(&'v self, key: Key<'_>) -> Option<Value<'v>>

fn count(&self) -> usize

impl<S> Source for [S] where
    S: Source, 

fn visit<'kvs>(&'kvs self, visitor: &mut dyn Visitor<'kvs>) -> Result<(), Error>

fn get<'v>(&'v self, key: Key<'_>) -> Option<Value<'v>>

fn count(&self) -> usize

impl<S> Source for Option<S> where
    S: Source, 

fn visit<'kvs>(&'kvs self, visitor: &mut dyn Visitor<'kvs>) -> Result<(), Error>

fn get<'v>(&'v self, key: Key<'_>) -> Option<Value<'v>>

fn count(&self) -> usize

impl<S> Source for Box<S> where
    S: Source + ?Sized, 

fn visit<'kvs>(&'kvs self, visitor: &mut dyn Visitor<'kvs>) -> Result<(), Error>

fn get<'v>(&'v self, key: Key<'_>) -> Option<Value<'v>>

fn count(&self) -> usize

impl<S> Source for Vec<S> where
    S: Source, 

fn visit<'kvs>(&'kvs self, visitor: &mut dyn Visitor<'kvs>) -> Result<(), Error>

fn get<'v>(&'v self, key: Key<'_>) -> Option<Value<'v>>

fn count(&self) -> usize

impl<K, V, S> Source for HashMap<K, V, S> where
    K: ToKey + Borrow<str> + Eq + Hash,
    V: ToValue,
    S: BuildHasher, 

fn visit<'kvs>(&'kvs self, visitor: &mut dyn Visitor<'kvs>) -> Result<(), Error>

fn get<'v>(&'v self, key: Key<'_>) -> Option<Value<'v>>

fn count(&self) -> usize

impl<K, V> Source for BTreeMap<K, V> where
    K: ToKey + Borrow<str> + Ord,
    V: ToValue, 

fn visit<'kvs>(&'kvs self, visitor: &mut dyn Visitor<'kvs>) -> Result<(), Error>

fn get<'v>(&'v self, key: Key<'_>) -> Option<Value<'v>>

fn count(&self) -> usize

Implementors

impl<S> Source for AsList<S> where
    S: Source, 

impl<S> Source for AsMap<S> where
    S: Source,