Trait postcard::de_flavors::Flavor

pub trait Flavor<'de>: 'de {
    type Remainder: 'de;
    type Source: 'de;

    // Required methods
    fn pop(&mut self) -> Result<u8>;
    fn try_take_n(&mut self, ct: usize) -> Result<&'de [u8]>;
    fn finalize(self) -> Result<Self::Remainder>;

    // Provided method
    fn size_hint(&self) -> Option<usize> { ... }
}

The deserialization Flavor trait

This is used as the primary way to decode serialized data from some kind of buffer, or modify that data in a middleware style pattern.

See the module level docs for an example of how flavors are used.

Required Associated Types

type Remainder: 'de

The remaining data of this flavor after deserializing has completed.

Typically, this includes the remaining buffer that was not used for deserialization, and in cases of more complex flavors, any additional information that was decoded or otherwise calculated during the deserialization process.

type Source: 'de

The source of data retrieved for deserialization.

This is typically some sort of data buffer, or another Flavor, when chained behavior is desired

Required Methods

fn pop(&mut self) -> Result<u8>

Obtain the next byte for deserialization

fn try_take_n(&mut self, ct: usize) -> Result<&'de [u8]>

Attempt to take the next ct bytes from the serialized message

fn finalize(self) -> Result<Self::Remainder>

Complete the deserialization process.

This is typically called separately, after the serde deserialization has completed.

Provided Methods

fn size_hint(&self) -> Option<usize>

Returns the number of bytes remaining in the message, if known.

Implementation notes

It is not enforced that this number is exactly correct. A flavor may yield less or more bytes than the what is hinted at by this function.

size_hint() is primarily intended to be used for optimizations such as reserving space for deserialized items, but must not be trusted to e.g., omit bounds checks in unsafe code. An incorrect implementation of size_hint() should not lead to memory safety violations.

That said, the implementation should provide a correct estimation, because otherwise it would be a violation of the trait’s protocol.

The default implementation returns None which is correct for any flavor.

Implementors

impl<'de> Flavor<'de> for Slice<'de>

type Remainder = &'de [u8]

type Source = &'de [u8]

impl<'de, T> Flavor<'de> for IOReader<'de, T>

where T: Read + 'de,

type Remainder = (T, &'de mut [u8])

type Source = &'de [u8]