The omission of Sink: Default is causing me a slight inconvenience in
a test harness. There seems little reason for this and Empty not to
be Clone and Copy too.
I have made all three of these insta-stable, because:
AIUI Copycan only be derived, and I was not able to find any
examples of how to unstably derive it. I think it is probably not
possible.
I hunted through the git history for precedent and found
79b8ad84c84481a43704213cd0948d2ba0ea63b4
Implement `Copy` for `IoSlice`
https://github.com/rust-lang/rust/pull/69403
which was also insta-stable.
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Due to the std/alloc split, it is not possible to make
`alloc::collections::TryReserveError::AllocError` non-exhaustive without
having an unstable, doc-hidden method to construct (which negates the
benefits from `#[non_exhaustive]`.
Add `io::Cursor::{remaining, remaining_slice, is_empty}`
Tracking issue: #86369
I came across an inconvenience when answering the following [Stack Overflow](https://stackoverflow.com/questions/67831170) question.
To get the remaining slice you have to call `buff.fill_buf().unwrap()`. Which in my opinion doesn't really tell you what is returned (in the context of Cursor). To improve readability and convenience when using Cursor i propose adding the method `remaining`.
The next thing i found inconvenient (unnecessary long) was detecting if the cursor reached the end. There are a few ways this can be achieved right now:
- `buff.fill_buf().unwrap().is_empty()`
- `buff.position() >= buff.get_ref().len()`
- `buff.bytes().next().is_none()`
Which all seem a bit unintuitive, hidden in trait documentations or just a bit long for such a simple task.
Therefor i propose another method called `is_empty`, maybe with another name, since this one may leave room for interpretation on what really is empty (the underlying slice, the remaining slice or maybe the position).
Since it seemed easier to create this PR instead of an RFC i did that, if an RFC is wanted, i can close this PR and write an RFC first.
Add has_data_left() to BufRead
This is a continuation of #40747 and also addresses #40745. The problem with the previous PR was that it had "eof" in its method name. This PR uses a more descriptive method name, but I'm open to changing it.
Specialize `io::Bytes::size_hint` for more types
Improve the result of `<io::Bytes as Iterator>::size_hint` for some readers. I did not manage to specialize `SizeHint` for `io::Cursor`
Side question: would it be interesting for `io::Read` to have an optional `size_hint` method ?
Rename IoSlice(Mut)::advance to advance_slice and add IoSlice(Mut)::advance
Also changes the signature of `advance_slice` to accept a `&mut &mut [IoSlice]`, not returning anything. This will better match the `IoSlice::advance` function.
Updates https://github.com/rust-lang/rust/issues/62726.
To make way for a new IoSlice(Mut)::advance function that advances a
single slice.
Also changes the signature to accept a `&mut &mut [IoSlice]`, not
returning anything. This will better match the future IoSlice::advance
function.
add an example to explain std::io::Read::read returning 0 in some cases
I have always found the explanation about `Read::read` returning 0 to indicate EOF but not indefinitely, so here's more info using Linux as example. I can also add example code if necessary
Move `std::memchr` to `sys_common`
`std::memchr` is a thin abstraction over the different `memchr` implementations in `sys`, along with documentation and tests. The module is only used internally by `std`, nothing is exported externally. Code like this is exactly what the `sys_common` module is for, so this PR moves it there.
Override `clone_from` for some types
Override `clone_from` method of the `Clone` trait for:
- `cell::RefCell`
- `cmp::Reverse`
- `io::Cursor`
- `mem::ManuallyDrop`
This can bring performance improvements.
Optimize for the common case where the input write size is less than the
buffer size. This slightly increases the cost for pathological write
patterns that commonly fill the buffer exactly, but if a client is doing
that frequently, they're already paying the cost of frequent flushing,
etc., so the cost is of this optimization to them is relatively small.
We use a Vec as our internal, constant-sized buffer, but the overhead of
using methods like `extend_from_slice` can be enormous, likely because
they don't get inlined, because `Vec` has to repeat bounds checks that
we've already done, and because it makes considerations for things like
reallocating, even though they should never happen.
Ensure that `write` and `write_all` can be inlined and that their
commonly executed fast paths can be as short as possible.
`write_vectored` would likely benefit from the same optimization, but I
omitted it because its implementation is more complex, and I don't have
a benchmark on hand to guide its optimization.
Stabilize `bufreader_seek_relative`
This PR marks `BufReader::seek_relative` as stable - the associated issue, #31100, has passed the final comment period without any issues, and from what I understand, the only thing left to stabilize this is to submit a PR marking the method as stable.
Closes#31100.
Rename `#[doc(spotlight)]` to `#[doc(notable_trait)]`
Fixes#80936.
"spotlight" is not a very specific or self-explaining name.
Additionally, the dialog that it triggers is called "Notable traits".
So, "notable trait" is a better name.
* Rename `#[doc(spotlight)]` to `#[doc(notable_trait)]`
* Rename `#![feature(doc_spotlight)]` to `#![feature(doc_notable_trait)]`
* Update documentation
* Improve documentation
r? `@Manishearth`
Derive Debug for io::Chain instead of manually implementing it.
This derives Debug for io::Chain instead of manually implementing it.
The manual implementation has the same bounds, so I don't think there's any reason for a manual implementation. The names used in the derive implementation are even nicer (`first`/`second`) than the manual implementation (`t`/`u`), and include the `done_first` field too.
The manual implementation has the same bounds, so I don't think there's
any reason for a manual implementation. The names used in the derive
implementation are even nicer (`first`/`second`) than the manual
implementation (`t`/`u`), and include the `done_first` field too.
