Trait log::kv::source::Source

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

    // Provided methods
    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<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

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<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 [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

Implementors

impl<S> Source for AsList<S>

where S: Source,

impl<S> Source for AsMap<S>

where S: Source,