The `Cow` type [1] requires that its generic parameter type implements
the `ToOwned` trait [2], which provides a method to create owned data
from borrowed data, usually by cloning.
However, it is infallible, and thus in most cases it is not useful for
the kernel. [3]
Therefore, introduce `cfg(no_borrow)` to remove the `borrow` module
(which contains `ToOwned` and `Cow`) from `alloc`.
Link: https://doc.rust-lang.org/alloc/borrow/enum.Cow.html [1]
Link: https://doc.rust-lang.org/alloc/borrow/trait.ToOwned.html [2]
Link: https://lore.kernel.org/rust-for-linux/20221204103153.117675b1@GaryWorkstation/ [3]
Cc: Gary Guo <gary@garyguo.net>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Finn Behrens <fin@nyantec.com>
Add `Vec::try_with_capacity()` and `Vec::try_with_capacity_in()` as
the fallible versions of `Vec::with_capacity()` and
`Vec::with_capacity_in()`, respectively.
The implementations follow the originals and use the previously
added `RawVec::try_with_capacity_in()`.
In turn, `Vec::try_with_capacity()` will be used to implement
the `CString` type (which wraps a `Vec<u8>`) in a later patch.
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Add the `RawVec::try_with_capacity_in()` constructor as the fallible
version of `RawVec::with_capacity_in()`.
The implementation follows the original.
The infallible constructor is implemented in terms of the private
`RawVec::allocate_in()` constructor, thus also add the private
`RawVec::try_allocate_in()` constructor following the other.
It will be used to implement `Vec::try_with_capacity{,_in}()` in
the next patch.
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This customizes the subset of the Rust standard library `alloc` that
was just imported as-is, mainly by:
- Adding SPDX license identifiers.
- Skipping modules (e.g. `rc` and `sync`) via new `cfg`s.
- Adding fallible (`try_*`) versions of existing infallible methods
(i.e. returning a `Result` instead of panicking).
Since the standard library requires stable/unstable attributes,
these additions are annotated with:
#[stable(feature = "kernel", since = "1.0.0")]
Using "kernel" as the feature allows to have the additions
clearly marked. The "1.0.0" version is just a placeholder.
(At the moment, only one is needed, but in the future more
fallible methods will be added).
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Matthew Bakhtiari <dev@mtbk.me>
Signed-off-by: Matthew Bakhtiari <dev@mtbk.me>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is a subset of the Rust standard library `alloc` crate,
version 1.62.0, licensed under "Apache-2.0 OR MIT", from:
https://github.com/rust-lang/rust/tree/1.62.0/library/alloc/src
The files are copied as-is, with no modifications whatsoever
(not even adding the SPDX identifiers).
For copyright details, please see:
https://github.com/rust-lang/rust/blob/1.62.0/COPYRIGHT
The next patch modifies these files as needed for use within
the kernel. This patch split allows reviewers to double-check
the import and to clearly see the differences introduced.
Vendoring `alloc`, at least for the moment, allows us to have fallible
allocations support (i.e. the `try_*` versions of methods which return
a `Result` instead of panicking) early on. It also gives a bit more
freedom to experiment with new interfaces and to iterate quickly.
Eventually, the goal is to have everything the kernel needs in
upstream `alloc` and drop it from the kernel tree.
For a summary of work on `alloc` happening upstream, please see:
https://github.com/Rust-for-Linux/linux/issues/408
The following script may be used to verify the contents:
for path in $(cd rust/alloc/ && find . -type f -name '*.rs'); do
curl --silent --show-error --location \
https://github.com/rust-lang/rust/raw/1.62.0/library/alloc/src/$path \
| diff --unified rust/alloc/$path - && echo $path: OK
done
Reviewed-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
