rust/library/std
Matthias Krüger 6826f33168
Rollup merge of #97917 - AronParker:master, r=ChrisDenton
Implement ExitCodeExt for Windows

Fixes #97914

### Motivation:

On Windows it is common for applications to return `HRESULT` (`i32`) or `DWORD` (`u32`) values. These stem from COM based components ([HRESULTS](https://docs.microsoft.com/en-us/windows/win32/api/objbase/nf-objbase-coinitialize)), Win32 errors ([GetLastError](https://docs.microsoft.com/en-us/windows/win32/api/errhandlingapi/nf-errhandlingapi-getlasterror)), GUI applications ([WM_QUIT](https://docs.microsoft.com/en-us/windows/win32/winmsg/wm-quit)) and more. The newly stabilized `ExitCode` provides an excellent fit for propagating these values, because `std::process::exit` does not run deconstructors which can result in errors. However, `ExitCode` currently only implements `From<u8> for ExitCode`, which disallows the full range of `i32`/`u32` values. This pull requests attempts to address that shortcoming by providing windows specific extensions that accept a `u32` value (which covers all possible `HRESULTS` and Win32 errors) analog to [ExitStatusExt::from_raw](https://doc.rust-lang.org/std/os/windows/process/trait.ExitStatusExt.html#tymethod.from_raw).

This was also intended by the original Stabilization https://github.com/rust-lang/rust/pull/93840#issue-1129209143=  as pointed out by ``@eggyal`` in https://github.com/rust-lang/rust/issues/97914#issuecomment-1151076755:

> Issues around platform specific representations: We resolved this issue by changing the return type of report from i32 to the opaque type ExitCode. __That way we can change the underlying representation without affecting the API, letting us offer full support for platform specific exit code APIs in the future.__

[Emphasis added]

### API

```rust
/// Windows-specific extensions to [`process::ExitCode`].
///
/// This trait is sealed: it cannot be implemented outside the standard library.
/// This is so that future additional methods are not breaking changes.
#[stable(feature = "windows_process_exit_code_from", since = "1.63.0")]
pub trait ExitCodeExt: Sealed {
    /// Creates a new `ExitCode` from the raw underlying `u32` return value of
    /// a process.
    #[stable(feature = "windows_process_exit_code_from", since = "1.63.0")]
    fn from_raw(raw: u32) -> Self;
}

#[stable(feature = "windows_process_exit_code_from", since = "1.63.0")]
impl ExitCodeExt for process::ExitCode {
    fn from_raw(raw: u32) -> Self {
        process::ExitCode::from_inner(From::from(raw))
    }
}
```

### Misc

I apologize in advance if I misplaced any attributes regarding stabilzation, as far as I learned traits are insta-stable so I chose to make them stable. If this is an error, please let me know and I'll correct it. I also added some additional machinery to make it work, analog to [ExitStatus](https://doc.rust-lang.org/std/process/struct.ExitStatus.html#).

EDIT: Proposal: https://github.com/rust-lang/libs-team/issues/48
2022-07-07 20:33:23 +02:00
..
benches mv std libs to library/ 2020-07-27 19:51:13 -05:00
primitive_docs Add primitive documentation to libcore 2021-09-12 02:23:08 +00:00
src Rollup merge of #97917 - AronParker:master, r=ChrisDenton 2022-07-07 20:33:23 +02:00
tests Fold aarch64 feature +fp into +neon 2022-03-22 15:14:33 -07:00
build.rs Horizon OS STD support 2022-06-13 20:44:39 -07:00
Cargo.toml library/std: Bump compiler_builtins 2022-05-26 21:11:16 +02:00