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ObjectHeader

Struct ObjectHeader 

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pub struct ObjectHeader {
    pub object_id: VarInt,
    pub extension_headers_length: VarInt,
    pub extensions: Vec<u8>,
    pub payload_length: VarInt,
    pub object_status: ObjectStatus,
}
Expand description

Object within a subgroup stream (draft-09).

Encoding: object_id(vi), extension_headers_length(vi), [extensions…], payload_length(vi), if payload_length == 0: object_status(vi) else: payload bytes

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§object_id: VarInt

Object identifier within the subgroup.

§extension_headers_length: VarInt

Total byte length of extension headers, as it arrived.

Advisory on encode. Every encoder here writes VarInt::from_usize(self.extensions.len()) and never reads this field, so a hand-built header whose stated length disagrees with the bytes beside it goes on the wire with the derived length and is read back consistent. Decoding always sets the two together, so a value that came off the wire never disagrees.

It is kept because it is what the peer stated, which is not always recoverable from the bytes: a non-minimal varint length encodes the same number in more bytes, and a relay that must forward the block unchanged has to know which it saw.

§extensions: Vec<u8>

Raw extension bytes (opaque).

§payload_length: VarInt

Length of the object payload in bytes.

§object_status: ObjectStatus

Status of this object.

Implementations§

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impl ObjectHeader

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pub fn encode(&self, buf: &mut impl BufMut)

Encode the object header into the buffer.

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pub fn encode_checked(&self, buf: &mut impl BufMut) -> Result<(), CodecError>

Encode the header, refusing a status the framing cannot carry.

Section 8.4.1 puts the Object Status field on the wire only when the Object Payload Length is zero, and Section 8.1.1.1 says “Any object with a status code other than zero MUST have an empty payload”. A non-zero status paired with a non-zero payload length therefore has no encoding at all: Self::encode drops the status and the peer reads an ordinary object, which is a different object from the one the caller described. This refuses instead.

The datagram types on this draft already refuse the same pairing. These two did not, and they are the ones a publisher writes on every stream.

§Errors

CodecError::InvalidField if a non-zero Object Status is paired with a non-zero Object Payload Length.

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pub fn decode(buf: &mut impl Buf) -> Result<Self, CodecError>

Decode an object header from the buffer.

Trait Implementations§

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impl Clone for ObjectHeader

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fn clone(&self) -> ObjectHeader

Returns a duplicate of the value. Read more
1.0.0 (const: unstable) · Source§

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

Performs copy-assignment from source. Read more
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impl Debug for ObjectHeader

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

Formats the value using the given formatter. Read more
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impl Eq for ObjectHeader

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impl PartialEq for ObjectHeader

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

Equality operator ==. Read more
1.0.0 (const: unstable) · Source§

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

Inequality operator !=. Read more
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impl StructuralPartialEq for ObjectHeader

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dest. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = !

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.