Struct protobuf_codec::field::MaybeDefault

pub struct MaybeDefault<T>(_);

Decoder and encoder for optional fields which have the default values.

If a field is missing in a target input stream, the default value is used as the field value instead.

Methods

impl<T> MaybeDefault<T>

pub fn new(inner: T) -> Self

Makes a new MaybeDefault instance.

pub fn inner_ref(&self) -> &T

Returns a reference to the inner field encoder/decoder.

pub fn inner_mut(&mut self) -> &mut T

Returns a mutable reference to the inner field encoder/decoder.

pub fn into_inner(self) -> T

Takes the ownership of the instance, and returns the inner field encoder/decoder.

Trait Implementations

impl<T: Debug> Debug for MaybeDefault<T>

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<T: Default> Default for MaybeDefault<T>

fn default() -> MaybeDefault<T>

Returns the "default value" for a type.

impl<D> Decode for MaybeDefault<D> where
    D: RequiredFieldDecode,
    D::Item: Default, 

type Item = D::Item

The type of items to be decoded.

fn decode(&mut self, buf: &[u8], eos: Eos) -> Result<usize>

Consumes the given buffer (a part of a byte sequence), and proceeds the decoding process.

fn finish_decoding(&mut self) -> Result<Self::Item>

Finishes the current decoding process and returns the decoded item.

fn is_idle(&self) -> bool

Returns true if there are no items to be decoded by the decoder at the next invocation of decode method, otherwise false.

fn requiring_bytes(&self) -> ByteCount

Returns the lower bound of the number of bytes needed to decode the next item.

impl<D> FieldDecode for MaybeDefault<D> where
    D: RequiredFieldDecode,
    D::Item: Default, 

fn start_decoding(&mut self, tag: Tag) -> Result<bool>

Tries to start decoding a field.

impl<E> Encode for MaybeDefault<E> where
    E: RequiredFieldEncode,
    E::Item: Default + PartialEq, 

type Item = E::Item

The type of items to be encoded.

fn encode(&mut self, buf: &mut [u8], eos: Eos) -> Result<usize>

Encodes the items in the encoder and writes the encoded bytes to the given buffer.

fn start_encoding(&mut self, item: Self::Item) -> Result<()>

Tries to start encoding the given item.

fn is_idle(&self) -> bool

Returns true if there are no items to be encoded in the encoder, otherwise false.

fn requiring_bytes(&self) -> ByteCount

Returns the number of bytes required to encode all the items in the encoder.

impl<E> SizedEncode for MaybeDefault<E> where
    E: RequiredFieldEncode + SizedEncode,
    E::Item: Default + PartialEq, 

fn exact_requiring_bytes(&self) -> u64

Returns the exact number of bytes required to encode all the items remaining in the encoder.

impl<E> FieldEncode for MaybeDefault<E> where
    E: RequiredFieldEncode,
    E::Item: Default + PartialEq,