If you were writing to something along the lines of `self.foo` then with the new
closure rules it meant that you were borrowing `self` for the entirety of the
closure, meaning that you couldn't format other fields of `self` at the same
time as writing to a buffer contained in `self`.
By lifting the borrow outside of the closure the borrow checker can better
understand that you're only borrowing one of the fields at a time. This had to
use type ascription as well in order to preserve trait object coercions.
It asserted that the previous count was always nonnegative, but DISCONNECTED is
a valid value for it to see. In order to continue to remember to store
DISCONNECTED after DISCONNECTED was seen, I also added a helper method.
Closes#12226
The `id` shouldn't be changed by external code, and exposing it publicly
allows to be accidentally changed.
Also, remove the first element special case in the `select!` macro.
This adopts the rules posted in #10432:
1. If a seek position is negative, then an error is generated
2. Seeks beyond the end-of-file are allowed. Future writes will fill the gap
with data and future reads will return errors.
3. Seeks within the bounds of a file are fine.
Closes#10432
This adopts the rules posted in #10432:
1. If a seek position is negative, then an error is generated
2. Seeks beyond the end-of-file are allowed. Future writes will fill the gap
with data and future reads will return errors.
3. Seeks within the bounds of a file are fine.
Closes#10432
This, the Nth rewrite of channels, is not a rewrite of the core logic behind
channels, but rather their API usage. In the past, we had the distinction
between oneshot, stream, and shared channels, but the most recent rewrite
dropped oneshots in favor of streams and shared channels.
This distinction of stream vs shared has shown that it's not quite what we'd
like either, and this moves the `std::comm` module in the direction of "one
channel to rule them all". There now remains only one Chan and one Port.
This new channel is actually a hybrid oneshot/stream/shared channel under the
hood in order to optimize for the use cases in question. Additionally, this also
reduces the cognitive burden of having to choose between a Chan or a SharedChan
in an API.
My simple benchmarks show no reduction in efficiency over the existing channels
today, and a 3x improvement in the oneshot case. I sadly don't have a
pre-last-rewrite compiler to test out the old old oneshots, but I would imagine
that the performance is comparable, but slightly slower (due to atomic reference
counting).
This commit also brings the bonus bugfix to channels that the pending queue of
messages are all dropped when a Port disappears rather then when both the Port
and the Chan disappear.
Beforehand, using a concurrent queue always mandated that the "shared state" be
stored internally to the queues in order to provide a safe interface. This isn't
quite as flexible as one would want in some circumstances, so instead this
commit moves the queues to not containing the shared state.
The queues no longer have a "default useful safe" interface, but rather a
"default safe" interface (minus the useful part). The queues have to be shared
manually through an Arc or some other means. This allows them to be a little
more flexible at the cost of a usability hindrance.
I plan on using this new flexibility to upgrade a channel to a shared channel
seamlessly.
I factored the commits by affected files, for the most part. The last 7 or 8 contain the meat of the PR. The rest are small changes to closures found in the codebase. Maybe interesting to read to see some of the impact of the rules.
r? @pcwalton
Fixes#6801
This is a fairly trivial (but IMHO handy) change to implement IterBytes for IpAddr and SocketAddr.
I originally stumbled across this because I wanted to use a SocketAddr as a HashMap key and discovered that I couldn't do it directly. Had to impl IterBytes on a new intermediate type to work around it.
Thinking about swap as an example of unsafe programming. This cleans it up a bit. It also removes type parametrization over `RawPtr` from the memcpy functions to make this compile.
It unsafe assumptions that any impl of RawPtr is for actual pointers,
that they can be copied by memcpy. Removing it is easy, so I don't
think it's solving a real problem.
Declare a `type SendStr = MaybeOwned<'static>` to ease readibility of
types that needed the old SendStr behavior.
Implement all the traits for MaybeOwned that SendStr used to implement.
- Convert the formatting traits to `&self` rather than `_: &Self`
- Rejig `syntax::ext::{format,deriving}` a little in preparation
- Implement `#[deriving(Show)]`
