Struct async_stm::queues::tchan::TChan

pub struct TChan<T> { /* private fields */ }

Ubounded queue using a linked list of TVars.

This implementation builds up a linked list of TVars with a read and a write pointer. The good thing is that the reads don’t cause retries in writes, unlike if it was just a single TVar with one data structure in it. It may also help that it’s more granular, and Transaction::downcast will not clone a full data structure.

Implementations

impl<T> TChan<T> where
    T: Any + Sync + Send + Clone, 

pub fn new() -> TChan<T>

Create an empty TChan.

Both read and write TVars will be pointing at a common TVar containing an empty list.

   [TNil]
  / \
[*]  [*]
read write

Trait Implementations

impl<T: Clone> Clone for TChan<T>

fn clone(&self) -> TChan<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Any + Send + Sync + Clone> Default for TChan<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T> TQueueLike<T> for TChan<T> where
    T: Any + Sync + Send + Clone, 

fn read(&self) -> StmResult<T>

Pop the head of the queue, or retry until there is an element if it’s empty.

Moves the read TVar down the list to point at the next item.

 [TCons(x, [TCons(y, [TNil])])]
 |         |         |
[ ]       [*]       [*]
read0 ->  read1     write

fn write(&self, value: T) -> StmResult<()>

Push to the end of the queue.

Replaces the contents of the current write TVar with a TCons and points the write TVar at a new TNil.

 [TCons(x, [TCons(y, [TNil])])]
 |         |         |
[*]       [ ]       [*]
read      write0 -> write1

fn is_empty(&self) -> StmResult<bool>

Check if the queue is empty.