Struct ValueStringCodecDescriptor 

pub struct ValueStringCodecDescriptor { /* private fields */ }

An immutable, safely erased bidirectional string codec for one value type.

Each operation creates a fresh default codec; no codec state is retained between calls. Type identities are process-local and names are diagnostic, not stable IDs.

Examples

use core::convert::Infallible;

use qubit_codec::ValueDecoder;
use qubit_codec::ValueEncoder;
use qubit_codec::ValueStringCodecDescriptor;

#[derive(Default)]
struct Text;
impl ValueEncoder<u32> for Text {
    type Output = String;
    type Error = Infallible;

    fn encode(&mut self, input: &u32) -> Result<String, Infallible> {
        Ok(input.to_string())
    }
}
impl ValueDecoder<str> for Text {
    type Output = u32;
    type Error = Infallible;

    fn decode(&mut self, input: &str) -> Result<u32, Infallible> {
        Ok(input.len() as u32)
    }
}

let descriptor = ValueStringCodecDescriptor::of::<Text, u32>();

// `encode` takes an erased `&dyn Any`, so the value type must be named.
let value: u32 = 7;
assert_eq!(descriptor.encode(&value).unwrap(), "7");

let decoded = descriptor.decode("hello").unwrap();
assert_eq!(*decoded.downcast::<u32>().unwrap(), 5);

Implementations

impl ValueStringCodecDescriptor

pub const fn of<C, V>() -> Self

where C: Default + ValueEncoder<V, Output = String> + ValueDecoder<str, Output = V> + 'static, <C as ValueEncoder<V>>::Error: Error + Send + Sync + 'static, <C as ValueDecoder<str>>::Error: Error + Send + Sync + 'static, V: 'static,

Creates a descriptor for codec C and value type V.

Both codec error types must implement Send + Sync so execution errors can retain their source across thread boundaries. The codec and value types themselves need not implement these traits; V only needs to be 'static because decoded values are returned through Any.

Type Parameters

• C: Default-constructible string encoder/decoder with owned errors.
• V: Owned value type accepted and produced by C.

Returns

Returns immutable function metadata without constructing a codec.

pub fn codec_type_id(&self) -> TypeId

Returns the process-local identity of the concrete codec.

Returns

Returns the TypeId of the codec this descriptor was built for.

pub fn codec_type_name(&self) -> &'static str

Returns the diagnostic name of the concrete codec.

Returns

Returns the type_name of the codec, for diagnostics only.

pub fn value_type_id(&self) -> TypeId

Returns the process-local identity of the decoded value.

Returns

Returns the TypeId of the value this descriptor accepts and produces.

pub fn value_type_name(&self) -> &'static str

Returns the diagnostic name of the decoded value.

Returns

Returns the type_name of the value, for diagnostics only.

pub fn encode( &self, value: &dyn Any, ) -> Result<String, ValueCodecExecutionError>

Encodes one erased value after checking its concrete type.

Parameters

• value: Borrowed value whose concrete type must match the descriptor.

Returns

Returns an owned string produced by a fresh default codec.

Errors

Returns a type mismatch or the typed encoder source error.

pub fn decode( &self, input: &str, ) -> Result<Box<dyn Any>, ValueCodecExecutionError>

Decodes one string into a safely erased value of the declared type.

Parameters

• input: String borrowed for one decoding operation.

Returns

Returns a boxed owned value that can be downcast to the declared type.

Errors

Returns the typed decoder source error.

Trait Implementations

impl Clone for ValueStringCodecDescriptor

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for ValueStringCodecDescriptor

impl Debug for ValueStringCodecDescriptor

fn fmt(&self, formatter: &mut Formatter<'_>) -> FmtResult

Formats descriptor metadata without invoking either codec function.

Parameters

• formatter: Destination receiving the diagnostic type names.

Returns

Returns success after both names have been formatted.

Errors

Returns the underlying formatting failure.