This adds initial, unstable, support for the wasm32-wasi target. Not all of Tokio's
features are supported yet as WASI's non-blocking APIs are still limited.
Refs: tokio-rs/tokio#4827
* util: add track_caller to public APIs
Functions that may panic can be annotated with `#[track_caller]` so that
in the event of a panic, the function where the user called the
panicking function is shown instead of the file and line within Tokio
source.
This change adds `#[track_caller]` to all the non-unstable public APIs in
tokio-util where the documentation describes how the function may panic
due to incorrect context or inputs.
In one place, an assert was added where the described behavior appeared
not to be implemented. The documentation for `DelayQueue::reserve`
states that the function will panic if the new capacity exceeds the
maximum number of entries the queue can contain. However, the function
didn't panic until a higher number caused by an allocation failure. This
is inconsistent with `DelayQueue::insert_at` which will panic if the
number of entries were to go over MAX_ENTRIES.
Tests are included to cover each potentially panicking function.
Refs: #4413
* fix tests on FreeBSD 32-bit (I hope)
Some tests were failing on FreeBSD 32-bit because the "times too far in
the future" for DelayQueue were also too far in the future for the OS.
Fixed by copying the MAX_DURATION value from where it's defined and
using it to create a duration that is just 1 more than the maximum. This
will start to break once we get close (within 2 and a bit years) of the
Epochalypse (19 Jan, 2038) - but a lot of other things are going to be
breaking on FreeBSD 32-bit by then anyway.
## Motivation
In many cases, it is desirable to spawn a set of tasks associated with
keys, with the ability to cancel them by key. As an example use case for
this sort of thing, see Tower's [`ReadyCache` type][1].
Now that PR #4530 adds a way of cancelling tasks in a
`tokio::task::JoinSet`, we can implement a map-like API based on the
same `IdleNotifiedSet` primitive.
## Solution
This PR adds an implementation of a `JoinMap` type to
`tokio_util::task`, using the `JoinSet` type from `tokio::task`, the
`AbortHandle` type added in #4530, and the new task IDs added in #4630.
Individual tasks can be aborted by key using the `JoinMap::abort`
method, and a set of tasks whose key match a given predicate can be
aborted using `JoinMap::abort_matching`.
When tasks complete, `JoinMap::join_one` returns their associated key
alongside the output from the spawned future, or the key and the
`JoinError` if the task did not complete successfully.
Overall, I think the way this works is pretty straightforward; much of
this PR is just API boilerplate to implement the union of applicable
APIs from `JoinSet` and `HashMap`. Unlike previous iterations on the
`JoinMap` API (e.g. #4538), this version is implemented entirely in
`tokio_util`, using only public APIs from the `tokio` crate. Currently,
the required `tokio` APIs are unstable, but implementing `JoinMap` in
`tokio-util` means we will never have to make stability commitments for
the `JoinMap` API itself.
[1]: https://github.com/tower-rs/tower/blob/master/tower/src/ready_cache/cache.rs
Signed-off-by: Eliza Weisman <[email protected]>
This change removes all references to `Stream` from
within the `tokio` crate and moves them into a new
`tokio-stream` crate. Most types have had their
`impl Stream` removed as well in-favor of their
inherent methods.
Closes#2870
This change is intended to do the minimum to unblock 0.3; as such, for now, we
duplicate the internal `time::wheel` structures in tokio-util, rather than trying
to refactor things at this stage.
Co-authored-by: Bryan Donlan <[email protected]>
This refactors I/O registration in a few ways:
- Cleans up the cached readiness in `PollEvented`. This cache used to
be helpful when readiness was a linked list of `*mut Node`s in
`Registration`. Previous refactors have turned `Registration` into just
an `AtomicUsize` holding the current readiness, so the cache is just
extra work and complexity. Gone.
- Polling the `Registration` for readiness now gives a `ReadyEvent`,
which includes the driver tick. This event must be passed back into
`clear_readiness`, so that the readiness is only cleared from `Registration`
if the tick hasn't changed. Previously, it was possible to clear the
readiness even though another thread had *just* polled the driver and
found the socket ready again.
- Registration now also contains an `async fn readiness`, which stores
wakers in an instrusive linked list. This allows an unbounded number
of tasks to register for readiness (previously, only 1 per direction (read
and write)). By using the intrusive linked list, there is no concern of
leaking the storage of the wakers, since they are stored inside the `async fn`
and released when the future is dropped.
- Registration retains a `poll_readiness(Direction)` method, to support
`AsyncRead` and `AsyncWrite`. They aren't able to use `async fn`s, and
so there are 2 reserved slots for those methods.
- IO types where it makes sense to have multiple tasks waiting on them
now take advantage of this new `async fn readiness`, such as `UdpSocket`
and `UnixDatagram`.
Additionally, this makes the `io-driver` "feature" internal-only (no longer
documented, not part of public API), and adds a second internal-only
feature, `io-readiness`, to group together linked list part of registration
that is only used by some of the IO types.
After a bit of discussion, changing stream-based transports (like
`TcpStream`) to have `async fn read(&self)` is punted, since that
is likely too easy of a footgun to activate.
Refs: #2779, #2728
Carl Lerche