Struct Impossible

pub struct Impossible<Ok, Error> { /* private fields */ }

Helper type for implementing a Serializer that does not support serializing one of the compound types.

This type cannot be instantiated, but implements every one of the traits corresponding to the Serializer compound types: SerializeSeq, SerializeTuple, SerializeTupleStruct, SerializeTupleVariant, SerializeMap, SerializeStruct, and SerializeStructVariant.

impl Serializer for MySerializer {
    type Ok = ();
    type Error = Error;

    type SerializeSeq = Impossible<(), Error>;
    /* other associated types */

    /// This data format does not support serializing sequences.
    fn serialize_seq(self,
                     len: Option<usize>)
                     -> Result<Self::SerializeSeq, Error> {
        // Given Impossible cannot be instantiated, the only
        // thing we can do here is to return an error.
        Err(...)
    }

    /* other Serializer methods */
}

Trait Implementations

impl<Ok, Error> SerializeMap for Impossible<Ok, Error>

where Error: Error,

type Ok = Ok

Must match the Ok type of our Serializer.

type Error = Error

Must match the Error type of our Serializer.

fn serialize_key<T>(&mut self, key: &T) -> Result<(), Error>

where T: ?Sized + Serialize,

Serialize a map key.

fn serialize_value<T>(&mut self, value: &T) -> Result<(), Error>

where T: ?Sized + Serialize,

Serialize a map value.

fn end(self) -> Result<Ok, Error>

Finish serializing a map.

fn serialize_entry<K, V>( &mut self, key: &K, value: &V, ) -> Result<(), Self::Error>

where K: ?Sized + Serialize, V: ?Sized + Serialize,

Serialize a map entry consisting of a key and a value.

impl<Ok, Error> SerializeSeq for Impossible<Ok, Error>

where Error: Error,

type Ok = Ok

Must match the Ok type of our Serializer.

type Error = Error

Must match the Error type of our Serializer.

fn serialize_element<T>(&mut self, value: &T) -> Result<(), Error>

where T: ?Sized + Serialize,

Serialize a sequence element.

fn end(self) -> Result<Ok, Error>

Finish serializing a sequence.

impl<Ok, Error> SerializeStruct for Impossible<Ok, Error>

where Error: Error,

type Ok = Ok

Must match the Ok type of our Serializer.

type Error = Error

Must match the Error type of our Serializer.

fn serialize_field<T>( &mut self, key: &'static str, value: &T, ) -> Result<(), Error>

where T: ?Sized + Serialize,

Serialize a struct field.

fn end(self) -> Result<Ok, Error>

Finish serializing a struct.

fn skip_field(&mut self, key: &'static str) -> Result<(), Self::Error>

Indicate that a struct field has been skipped.

impl<Ok, Error> SerializeStructVariant for Impossible<Ok, Error>

where Error: Error,

type Ok = Ok

Must match the Ok type of our Serializer.

type Error = Error

Must match the Error type of our Serializer.

fn serialize_field<T>( &mut self, key: &'static str, value: &T, ) -> Result<(), Error>

where T: ?Sized + Serialize,

Serialize a struct variant field.

fn end(self) -> Result<Ok, Error>

Finish serializing a struct variant.

fn skip_field(&mut self, key: &'static str) -> Result<(), Self::Error>

Indicate that a struct variant field has been skipped.

impl<Ok, Error> SerializeTuple for Impossible<Ok, Error>

where Error: Error,

type Ok = Ok

Must match the Ok type of our Serializer.

type Error = Error

Must match the Error type of our Serializer.

fn serialize_element<T>(&mut self, value: &T) -> Result<(), Error>

where T: ?Sized + Serialize,

Serialize a tuple element.

fn end(self) -> Result<Ok, Error>

Finish serializing a tuple.

impl<Ok, Error> SerializeTupleStruct for Impossible<Ok, Error>

where Error: Error,

type Ok = Ok

Must match the Ok type of our Serializer.

type Error = Error

Must match the Error type of our Serializer.

fn serialize_field<T>(&mut self, value: &T) -> Result<(), Error>

where T: ?Sized + Serialize,

Serialize a tuple struct field.

fn end(self) -> Result<Ok, Error>

Finish serializing a tuple struct.

impl<Ok, Error> SerializeTupleVariant for Impossible<Ok, Error>

where Error: Error,

type Ok = Ok

Must match the Ok type of our Serializer.

type Error = Error

Must match the Error type of our Serializer.

fn serialize_field<T>(&mut self, value: &T) -> Result<(), Error>

where T: ?Sized + Serialize,

Serialize a tuple variant field.

fn end(self) -> Result<Ok, Error>

Finish serializing a tuple variant.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 0 bytes (uninhabited)