Being a person who somehow has taken a liking to premature optimisation, my knee-jerk reaction to
locking in std handles was preamble resembling following snippet:
let stdout = stdout();
let lstdout = stdout.lock();
let stdin = stdin();
let lstdin = stdin.lock();
and then reading from the locked handle like this:
let mut letter = [0; 1];
lstdin.read(&mut letter).unwrap();
As it is now this code will deadlock because the `read` method attempts to lock stdout as well!
r? @alexcrichton
---
Either way, I find flushing stdout when stdin is used debatable. I believe people who write prompts should take care to flush stdout when necessary themselves.
Another idea: Would be cool if locks on std handles would be taken for a thread, rather than a handle, so given preamble (first code snippet)
stdin.lock()
or more generally
stdin.read(…)
worked fine. I.e. if more than a single lock are all taken inside the same thread, it would work, though not sure if our synchronisation primitives are expressive enough to make it possible.
Being a person who somehow has taken a liking to premature optimisation, my knee-jerk reaction to
locking in std handles was preamble resembling following snippet:
let stdout = stdout();
let lstdout = stdout.lock();
let stdin = stdin();
let lstdin = stdin.lock();
and then reading from the locked handle like this:
let mut letter = [0; 1];
lstdin.read(&mut letter).unwrap();
As it is now this code will deadlock because the `read` method attempts to lock stdout as well!
The new `io` module has had some time to bake and this commit stabilizes some of
the utilities associated with it. This commit also deprecates a number of
`std::old_io::util` functions and structures.
These items are now `#[stable]`
* `Cursor`
* `Cursor::{new, into_inner, get_ref, get_mut, position, set_position}`
* Implementations of I/O traits for `Cursor<T>`
* Delegating implementations of I/O traits for references and `Box` pointers
* Implementations of I/O traits for primitives like slices and `Vec<T>`
* `ReadExt::bytes`
* `Bytes` (and impls)
* `ReadExt::chain`
* `Chain` (and impls)
* `ReadExt::take` (and impls)
* `BufReadExt::lines`
* `Lines` (and impls)
* `io::copy`
* `io::{empty, Empty}` (and impls)
* `io::{sink, Sink}` (and impls)
* `io::{repeat, Repeat}` (and impls)
These items remain `#[unstable]`
* Core I/O traits. These may want a little bit more time to bake along with the
commonly used methods like `read_to_end`.
* `BufReadExt::split` - this function may be renamed to not conflict with
`SliceExt::split`.
* `Error` - there are a number of questions about its representation,
`ErrorKind`, and usability.
These items are now `#[deprecated]` in `old_io`
* `LimitReader` - use `take` instead
* `NullWriter` - use `io::sink` instead
* `ZeroReader` - use `io::repeat` instead
* `NullReader` - use `io::empty` instead
* `MultiWriter` - use `broadcast` instead
* `ChainedReader` - use `chain` instead
* `TeeReader` - use `tee` instead
* `copy` - use `io::copy` instead
[breaking-change]
The new `io` module has had some time to bake and this commit stabilizes some of
the utilities associated with it. This commit also deprecates a number of
`std::old_io::util` functions and structures.
These items are now `#[stable]`
* `Cursor`
* `Cursor::{new, into_inner, get_ref, get_mut, position, set_position}`
* Implementations of I/O traits for `Cursor<T>`
* Delegating implementations of I/O traits for references and `Box` pointers
* Implementations of I/O traits for primitives like slices and `Vec<T>`
* `ReadExt::bytes`
* `Bytes` (and impls)
* `ReadExt::chain`
* `Chain` (and impls)
* `ReadExt::take` (and impls)
* `BufReadExt::lines`
* `Lines` (and impls)
* `io::copy`
* `io::{empty, Empty}` (and impls)
* `io::{sink, Sink}` (and impls)
* `io::{repeat, Repeat}` (and impls)
These items remain `#[unstable]`
* Core I/O traits. These may want a little bit more time to bake along with the
commonly used methods like `read_to_end`.
* `BufReadExt::split` - this function may be renamed to not conflict with
`SliceExt::split`.
* `Error` - there are a number of questions about its representation,
`ErrorKind`, and usability.
These items are now `#[deprecated]` in `old_io`
* `LimitReader` - use `take` instead
* `NullWriter` - use `io::sink` instead
* `ZeroReader` - use `io::repeat` instead
* `NullReader` - use `io::empty` instead
* `MultiWriter` - use `broadcast` instead
* `ChainedReader` - use `chain` instead
* `TeeReader` - use `tee` instead
* `copy` - use `io::copy` instead
[breaking-change]
This is an implementation of RFC 899 and adds stdio functionality to the new
`std::io` module. Details of the API can be found on the RFC, but from a high
level:
* `io::{stdin, stdout, stderr}` constructors are now available. There are also
`*_raw` variants for unbuffered and unlocked access.
* All handles are globally shared (excluding raw variants).
* The stderr handle is no longer buffered.
* All handles can be explicitly locked (excluding the raw variants).
The `print!` and `println!` machinery has not yet been hooked up to these
streams just yet. The `std::fmt::output` module has also not yet been
implemented as part of this commit.
Specifically, the following actions were takend:
* The `copy_memory` and `copy_nonoverlapping_memory` functions
to drop the `_memory` suffix (as it's implied by the functionality). Both
functions are now marked as `#[stable]`.
* The `set_memory` function was renamed to `write_bytes` and is now stable.
* The `zero_memory` function is now deprecated in favor of `write_bytes`
directly.
* The `Unique` pointer type is now behind its own feature gate called `unique`
to facilitate future stabilization.
[breaking-change]
Specifically, the following actions were taken:
* The `copy_memory` and `copy_nonoverlapping_memory` functions
to drop the `_memory` suffix (as it's implied by the functionality). Both
functions are now marked as `#[stable]`.
* The `set_memory` function was renamed to `write_bytes` and is now stable.
* The `zero_memory` function is now deprecated in favor of `write_bytes`
directly.
* The `Unique` pointer type is now behind its own feature gate called `unique`
to facilitate future stabilization.
* All type parameters now are `T: ?Sized` wherever possible and new clauses were
added to the `offset` functions to require that the type is sized.
[breaking-change]
* Adds features and allows
* Removes unused muts, unused imports, dead code
* Migrates some deprecated code to new io/env
* Changes std::num::uint/int to be re-exports of std::num::usize/isize
libcollections, liballoc, and libcoretest no longer warn during testing.
libstd warns much less, though there's some dangly bits that weren't obvious fixes. In particular, how to only supress deprecated warnings in specific submodules of std.
This commit is an implementation of [RFC 739][rfc] which adds a new `std::fs`
module to the standard library. This module provides much of the same
functionality as `std::old_io::fs` but it has many tweaked APIs as well as uses
the new `std::path` module.
[rfc]: https://github.com/rust-lang/rfcs/pull/739
This commit is an implementation of [RFC 739][rfc] which adds a new `std::fs`
module to the standard library. This module provides much of the same
functionality as `std::old_io::fs` but it has many tweaked APIs as well as uses
the new `std::path` module.
[rfc]: https://github.com/rust-lang/rfcs/pull/739
New functions, `slice::from_raw_parts` and `slice::from_raw_parts_mut`,
are added to implement the lifetime convention as agreed in rust-lang/rfcs#556.
The functions `slice::from_raw_buf` and `slice::from_raw_mut_buf` are
left deprecated for the time being.
Holding back on changing the signature of `std::ffi::c_str_to_bytes` as consensus in rust-lang/rfcs#592 is building to replace it with a composition of other functions.
Contribution to #21923.
This commit is an implementation of [RFC 576][rfc] which adds back the `std::io`
module to the standard library. No functionality in `std::old_io` has been
deprecated just yet, and the new `std::io` module is behind the same `io`
feature gate.
[rfc]: https://github.com/rust-lang/rfcs/pull/576
A good bit of functionality was copied over from `std::old_io`, but many tweaks
were required for the new method signatures. Behavior such as precisely when
buffered objects call to the underlying object may have been tweaked slightly in
the transition. All implementations were audited to use composition wherever
possible. For example the custom `pos` and `cap` cursors in `BufReader` were
removed in favor of just using `Cursor<Vec<u8>>`.
A few liberties were taken during this implementation which were not explicitly
spelled out in the RFC:
* The old `LineBufferedWriter` is now named `LineWriter`
* The internal representation of `Error` now favors OS error codes (a
0-allocation path) and contains a `Box` for extra semantic data.
* The io prelude currently reexports `Seek` as `NewSeek` to prevent conflicts
with the real prelude reexport of `old_io::Seek`
* The `chars` method was moved from `BufReadExt` to `ReadExt`.
* The `chars` iterator returns a custom error with a variant that explains that
the data was not valid UTF-8.
In preparation for the I/O rejuvination of the standard library, this commit
renames the current `io` module to `old_io` in order to make room for the new
I/O modules. It is expected that the I/O RFCs will land incrementally over time
instead of all at once, and this provides a fresh clean path for new modules to
enter into as well as guaranteeing that all old infrastructure will remain in
place for some time.
As each `old_io` module is replaced it will be deprecated in-place for new
structures in `std::{io, fs, net}` (as appropriate).
This commit does *not* leave a reexport of `old_io as io` as the deprecation
lint does not currently warn on this form of use. This is quite a large breaking
change for all imports in existing code, but all functionality is retained
precisely as-is and path statements simply need to be renamed from `io` to
`old_io`.
[breaking-change]
This commit is an implementation of [RFC 565][rfc] which is a stabilization of
the `std::fmt` module and the implementations of various formatting traits.
Specifically, the following changes were performed:
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0565-show-string-guidelines.md
* The `Show` trait is now deprecated, it was renamed to `Debug`
* The `String` trait is now deprecated, it was renamed to `Display`
* Many `Debug` and `Display` implementations were audited in accordance with the
RFC and audited implementations now have the `#[stable]` attribute
* Integers and floats no longer print a suffix
* Smart pointers no longer print details that they are a smart pointer
* Paths with `Debug` are now quoted and escape characters
* The `unwrap` methods on `Result` now require `Display` instead of `Debug`
* The `Error` trait no longer has a `detail` method and now requires that
`Display` must be implemented. With the loss of `String`, this has moved into
libcore.
* `impl<E: Error> FromError<E> for Box<Error>` now exists
* `derive(Show)` has been renamed to `derive(Debug)`. This is not currently
warned about due to warnings being emitted on stage1+
While backwards compatibility is attempted to be maintained with a blanket
implementation of `Display` for the old `String` trait (and the same for
`Show`/`Debug`) this is still a breaking change due to primitives no longer
implementing `String` as well as modifications such as `unwrap` and the `Error`
trait. Most code is fairly straightforward to update with a rename or tweaks of
method calls.
[breaking-change]
Closes#21436
As discussed with @aturon, this PR removes the `Send` bound from `std::error::Error`, allowing us to implement `Error` for error types containing non-`Send` types. Current examples include `PoisonError` and `TryLockError` from `std::sync` which contain a Guard that we don't want sent between tasks.
[breaking-change]
