Struct OptionalVisitor

pub struct OptionalVisitor<T, B>
where
    B: AsyncBufRead + Unpin,
    T: FromXml<B>,
{ /* private fields */ }

A visitor for deserializing empty XML elements as an Option::None

All visit_* calls will be forwarded to an inner visitor but build() will return None if no visit_* methods have been called and the inner visitor returns an error on building.

Trait Implementations

impl<T, B> Default for OptionalVisitor<T, B>

where B: AsyncBufRead + Unpin, T: FromXml<B>,

fn default() -> Self

Returns the “default value” for a type.

impl<B, T> Visitor<B> for OptionalVisitor<T, B>

where B: AsyncBufRead + Unpin, T: FromXml<B>,

type Output = Option<T>

Output type this Visitor returns

fn start_name() -> Option<&'static str>

Should return the expected starting tag name, if any

fn visit_attribute(&mut self, name: &str, value: &str) -> Result<(), Error>

Visit an attribute with the given name and value

fn visit_child<'life0, 'life1, 'life2, 'async_trait>( &'life0 mut self, name: &'life1 str, reader: &'life2 mut PeekingReader<B>, ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Visit a child element with the given tag name

fn visit_text(&mut self, text: &str) -> Result<(), Error>

Visit any plain text contained in the element

fn build(self) -> Result<Self::Output, Error>

Validate and build the output type

fn visit_tag(&mut self, name: &str) -> Result<(), Error>

Visit the starting tag with the given name