Struct ChainBuilder

pub struct ChainBuilder(/* private fields */);

Builder for a Chain

Implementations

impl ChainBuilder

pub fn new() -> Self

Construct a new ChainBuilder

pub fn amend_next(self, next: u16) -> Self

Amend the last descriptor added with a specific next value.

By default the next field in the published ring::Desc will be set automatically by the FakeQueue when publishing the chain, since the FakeQueue is the one allocating the actual descriptor ring slots.

For testing this can be used to override the next field that FakeQueue::publish will generate and is intended for creating broken descriptor chains. It is not intended that this can be used and result in a properly functioning chain and queue.

Panics

Will panic if no descriptor has yet been added to the chain.

pub fn readable<T: Copy>(self, data: &[T], mem: &IdentityDriverMem) -> Self

Append new readable descriptor with a copy of data

Panics

Will panic if there is not enough memory to allocate a buffer to hold data.

pub fn zeroed( self, access: DescAccess, data_len: u32, mem: &IdentityDriverMem, ) -> Self

Append an empty descriptor of the specified type and length

Panics

Will panic if there is not enough memory to allocate a buffer of len data_len.

pub fn reference( self, access: DescAccess, data_addr: u64, data_len: u32, ) -> Self

Append a descriptor with raw data.

This does not perform any allocations and will pass through the exact data_addr and data_len provided.

pub fn readable_zeroed(self, len: u32, mem: &IdentityDriverMem) -> Self

pub fn readable_reference(self, addr: u64, len: u32) -> Self

pub fn writable(self, len: u32, mem: &IdentityDriverMem) -> Self

pub fn writable_reference(self, addr: u64, len: u32) -> Self

pub fn build(self) -> Chain

Consume the builder and produce a Chain.