Trait frame_support::dispatch::Input

pub trait Input {
    // Required methods
    fn remaining_len(&mut self) -> Result<Option<usize>, Error>;
    fn read(&mut self, into: &mut [u8]) -> Result<(), Error>;

    // Provided methods
    fn read_byte(&mut self) -> Result<u8, Error> { ... }
    fn descend_ref(&mut self) -> Result<(), Error> { ... }
    fn ascend_ref(&mut self) { ... }
}

Trait that allows reading of data into a slice.

Required Methods

fn remaining_len(&mut self) -> Result<Option<usize>, Error>

Should return the remaining length of the input data. If no information about the input length is available, None should be returned.

The length is used to constrain the preallocation while decoding. Returning a garbage length can open the doors for a denial of service attack to your application. Otherwise, returning None can decrease the performance of your application.

fn read(&mut self, into: &mut [u8]) -> Result<(), Error>

Read the exact number of bytes required to fill the given buffer.

Note that this function is similar to std::io::Read::read_exact and not std::io::Read::read.

Provided Methods

fn read_byte(&mut self) -> Result<u8, Error>

Read a single byte from the input.

fn descend_ref(&mut self) -> Result<(), Error>

Descend into nested reference when decoding. This is called when decoding a new refence-based instance, such as Vec or Box. Currently all such types are allocated on the heap.

fn ascend_ref(&mut self)

Ascend to previous structure level when decoding. This is called when decoding reference-based type is finished.

Implementations on Foreign Types

impl<'a> Input for &'a [u8]

fn remaining_len(&mut self) -> Result<Option<usize>, Error>

fn read(&mut self, into: &mut [u8]) -> Result<(), Error>

impl<'a> Input for TrailingZeroInput<'a>

fn remaining_len(&mut self) -> Result<Option<usize>, Error>

fn read(&mut self, into: &mut [u8]) -> Result<(), Error>

impl<'a, T> Input for AppendZerosInput<'a, T>where T: Input,

fn remaining_len(&mut self) -> Result<Option<usize>, Error>

fn read(&mut self, into: &mut [u8]) -> Result<(), Error>

Implementors

impl<R> Input for IoReader<R>where R: Read,