Struct tokio_util::codec::LinesCodec

pub struct LinesCodec {
    next_index: usize,
    max_length: usize,
    is_discarding: bool,
}

A simple Decoder and Encoder implementation that splits up data into lines.

This uses the \n character as the line ending on all platforms.

Fields

next_index: usize

max_length: usize

The maximum length for a given line. If usize::MAX, lines will be read until a \n character is reached.

is_discarding: bool

Are we currently discarding the remainder of a line which was over the length limit?

Implementations

impl LinesCodec

pub fn new() -> LinesCodec

Returns a LinesCodec for splitting up data into lines.

Note

The returned LinesCodec will not have an upper bound on the length of a buffered line. See the documentation for new_with_max_length for information on why this could be a potential security risk.

pub fn new_with_max_length(max_length: usize) -> Self

Returns a LinesCodec with a maximum line length limit.

If this is set, calls to LinesCodec::decode will return a LinesCodecError when a line exceeds the length limit. Subsequent calls will discard up to limit bytes from that line until a newline character is reached, returning None until the line over the limit has been fully discarded. After that point, calls to decode will function as normal.

Note

Setting a length limit is highly recommended for any LinesCodec which will be exposed to untrusted input. Otherwise, the size of the buffer that holds the line currently being read is unbounded. An attacker could exploit this unbounded buffer by sending an unbounded amount of input without any \n characters, causing unbounded memory consumption.

pub fn max_length(&self) -> usize

Returns the maximum line length when decoding.

use std::usize;
use tokio_util::codec::LinesCodec;

let codec = LinesCodec::new();
assert_eq!(codec.max_length(), usize::MAX);

use tokio_util::codec::LinesCodec;

let codec = LinesCodec::new_with_max_length(256);
assert_eq!(codec.max_length(), 256);

Trait Implementations

impl Clone for LinesCodec

fn clone(&self) -> LinesCodec

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for LinesCodec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Decoder for LinesCodec

type Item = String

The type of decoded frames.

type Error = LinesCodecError

The type of unrecoverable frame decoding errors.

fn decode( &mut self, buf: &mut BytesMut, ) -> Result<Option<String>, LinesCodecError>

Attempts to decode a frame from the provided buffer of bytes.

fn decode_eof( &mut self, buf: &mut BytesMut, ) -> Result<Option<String>, LinesCodecError>

A default method available to be called when there are no more bytes available to be read from the underlying I/O.

fn framed<T: AsyncRead + AsyncWrite + Sized>(self, io: T) -> Framed<T, Self>

where Self: Sized,

Provides a Stream and Sink interface for reading and writing to this Io object, using Decode and Encode to read and write the raw data.

impl Default for LinesCodec

fn default() -> Self

Returns the “default value” for a type.

impl<T> Encoder<T> for LinesCodec

where T: AsRef<str>,

type Error = LinesCodecError

The type of encoding errors.

fn encode(&mut self, line: T, buf: &mut BytesMut) -> Result<(), LinesCodecError>

Encodes a frame into the buffer provided.

impl Hash for LinesCodec

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for LinesCodec

fn cmp(&self, other: &LinesCodec) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl PartialEq for LinesCodec

fn eq(&self, other: &LinesCodec) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for LinesCodec

fn partial_cmp(&self, other: &LinesCodec) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Eq for LinesCodec

impl StructuralPartialEq for LinesCodec