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DatagramHeader

Struct DatagramHeader 

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pub struct DatagramHeader {
    pub track_alias: VarInt,
    pub group_id: VarInt,
    pub object_id: VarInt,
    pub publisher_priority: u8,
    pub extension_headers_length: VarInt,
    pub extensions: Vec<u8>,
    pub end_of_group: bool,
}

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§track_alias: VarInt§group_id: VarInt§object_id: VarInt§publisher_priority: u8§extension_headers_length: VarInt§extensions: Vec<u8>§end_of_group: bool

Whether this object is the last one in its group.

Draft-12 added this flag and put it in the datagram type rather than in the header body, so it is not written or read by the methods below; DatagramType::is_end_of_group is where it lives on the wire.

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impl DatagramHeader

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

Encode the datagram header in the framing that carries no extension block.

Lossy in the same way the subgroup object header is: an extension block this value holds is dropped, because the framing being written has no field for it. The type byte decides which framing is right, and this entry point does not write the type byte, so it cannot consult it. Datagram::encode does both together and never disagrees with itself; this is the piece for a caller that has already written the type.

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pub fn encode_with_extensions( &self, has_extensions: bool, buf: &mut impl BufMut, )

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

Encode the datagram header, refusing what this framing cannot carry.

No status is ever refused, and that is a fact about this draft rather than a check left out. This is the OBJECT_DATAGRAM of Section 9.3.1, whose layout carries no Object Status field at all; a datagram that states a status is the separate OBJECT_DATAGRAM_STATUS message, modelled here as DatagramStatusHeader. So there is no status for Self::encode to drop, and nothing for Section 9.2.1.1’s “Any object with a status code other than zero MUST have an empty payload” to rule on: an object framed this way has status zero by construction.

The extension block is a different matter. Self::encode writes the framing without one, so a block this value holds has nowhere to go, and dropping it silently is what puts a datagram on the wire describing something other than what the caller built. That is refused here.

The fallible signature is also what lets one entry point span every draft. dispatch::AnyDatagramHeader::encode calls this on all thirteen, and the drafts whose payload-bearing datagram does carry a status field need somewhere to say no.

§Errors

CodecError::InvalidField if the value carries extension headers, which this framing has no field for.

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

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

Trait Implementations§

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impl Clone for DatagramHeader

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fn clone(&self) -> DatagramHeader

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 DatagramHeader

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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 DatagramHeader

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impl PartialEq for DatagramHeader

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fn eq(&self, other: &DatagramHeader) -> 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 DatagramHeader

Auto Trait 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.