Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Better docs and associated SUCCESS/FAILURE for process::ExitCode #48618

Merged
merged 3 commits into from
Mar 8, 2018
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
71 changes: 43 additions & 28 deletions src/libstd/process.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1080,14 +1080,45 @@ impl fmt::Display for ExitStatus {
}
}

/// This is ridiculously unstable, as it's a completely-punted-upon part
/// of the `?`-in-`main` RFC. It's here only to allow experimenting with
/// returning a code directly from main. It will definitely change
/// drastically before being stabilized, if it doesn't just get deleted.
#[doc(hidden)]
/// This type represents the status code a process can return to its
/// parent under normal termination.
///
/// Numeric values used in this type don't have portable meanings, and
/// different platforms may mask different amounts of them.
///
/// For the platform's canonical successful and unsuccessful codes, see
/// the [`SUCCESS`] and [`FAILURE`] associated items.
///
/// [`SUCCESS`]: #associatedconstant.SUCCESS
/// [`FAILURE`]: #associatedconstant.FAILURE
///
/// **Warning**: While various forms of this were discussed in [RFC #1937],
/// it was ultimately cut from that RFC, and thus this type is more subject
/// to change even than the usual unstable item churn.
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

as an aside, I just ran into a place where I really wanted this today. I was already calling exit(1) -- so it seems silly not to provide a way to "return" that...

///
/// [RFC #1937]: https://github.com/rust-lang/rfcs/pull/1937
#[derive(Clone, Copy, Debug)]
#[unstable(feature = "process_exitcode_placeholder", issue = "43301")]
pub struct ExitCode(pub i32);
#[unstable(feature = "process_exitcode_placeholder", issue = "48711")]
pub struct ExitCode(imp::ExitCode);

#[unstable(feature = "process_exitcode_placeholder", issue = "48711")]
impl ExitCode {
/// The canonical ExitCode for successful termination on this platform.
///
/// Note that a `()`-returning `main` implicitly results in a successful
/// termination, so there's no need to return this from `main` unless
/// you're also returning other possible codes.
#[unstable(feature = "process_exitcode_placeholder", issue = "48711")]
pub const SUCCESS: ExitCode = ExitCode(imp::ExitCode::SUCCESS);

/// The canonical ExitCode for unsuccessful termination on this platform.
///
/// If you're only returning this and `SUCCESS` from `main`, consider
/// instead returning `Err(_)` and `Ok(())` respectively, which will
/// return the same codes (but will also `eprintln!` the error).
#[unstable(feature = "process_exitcode_placeholder", issue = "48711")]
pub const FAILURE: ExitCode = ExitCode(imp::ExitCode::FAILURE);
}

impl Child {
/// Forces the child to exit. This is equivalent to sending a
Expand Down Expand Up @@ -1401,18 +1432,6 @@ pub fn id() -> u32 {
::sys::os::getpid()
}

#[cfg(target_arch = "wasm32")]
mod exit {
pub const SUCCESS: i32 = 0;
pub const FAILURE: i32 = 1;
}
#[cfg(not(target_arch = "wasm32"))]
mod exit {
use libc;
pub const SUCCESS: i32 = libc::EXIT_SUCCESS;
pub const FAILURE: i32 = libc::EXIT_FAILURE;
}

/// A trait for implementing arbitrary return types in the `main` function.
///
/// The c-main function only supports to return integers as return type.
Expand All @@ -1433,18 +1452,15 @@ pub trait Termination {

#[unstable(feature = "termination_trait_lib", issue = "43301")]
impl Termination for () {
fn report(self) -> i32 { exit::SUCCESS }
fn report(self) -> i32 { ExitCode::SUCCESS.report() }
}

#[unstable(feature = "termination_trait_lib", issue = "43301")]
impl<E: fmt::Debug> Termination for Result<(), E> {
fn report(self) -> i32 {
match self {
Ok(val) => val.report(),
Err(err) => {
eprintln!("Error: {:?}", err);
exit::FAILURE
}
Ok(()) => ().report(),
Err(err) => Err::<!, _>(err).report(),
}
}
}
Expand All @@ -1459,15 +1475,14 @@ impl<E: fmt::Debug> Termination for Result<!, E> {
fn report(self) -> i32 {
let Err(err) = self;
eprintln!("Error: {:?}", err);
exit::FAILURE
ExitCode::FAILURE.report()
}
}

#[unstable(feature = "termination_trait_lib", issue = "43301")]
impl Termination for ExitCode {
fn report(self) -> i32 {
let ExitCode(code) = self;
code
self.0.as_i32()
}
}

Expand Down
12 changes: 12 additions & 0 deletions src/libstd/sys/cloudabi/shims/process.rs
Original file line number Diff line number Diff line change
Expand Up @@ -126,6 +126,18 @@ impl fmt::Display for ExitStatus {
}
}

#[derive(PartialEq, Eq, Clone, Copy, Debug)]
pub struct ExitCode(bool);

impl ExitCode {
pub const SUCCESS: ExitCode = ExitCode(false);
pub const FAILURE: ExitCode = ExitCode(true);

pub fn as_i32(&self) -> i32 {
self.0 as i32
}
}

pub struct Process(Void);

impl Process {
Expand Down
13 changes: 13 additions & 0 deletions src/libstd/sys/redox/process.rs
Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@ use ffi::OsStr;
use os::unix::ffi::OsStrExt;
use fmt;
use io::{self, Error, ErrorKind};
use libc::{EXIT_SUCCESS, EXIT_FAILURE};
use path::{Path, PathBuf};
use sys::fd::FileDesc;
use sys::fs::{File, OpenOptions};
Expand Down Expand Up @@ -480,6 +481,18 @@ impl fmt::Display for ExitStatus {
}
}

#[derive(PartialEq, Eq, Clone, Copy, Debug)]
pub struct ExitCode(u8);

impl ExitCode {
pub const SUCCESS: ExitCode = ExitCode(EXIT_SUCCESS as _);
pub const FAILURE: ExitCode = ExitCode(EXIT_FAILURE as _);

pub fn as_i32(&self) -> i32 {
self.0 as i32
}
}

/// The unique id of the process (this should never be negative).
pub struct Process {
pid: usize,
Expand Down
2 changes: 1 addition & 1 deletion src/libstd/sys/unix/process/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.

pub use self::process_common::{Command, ExitStatus, Stdio, StdioPipes};
pub use self::process_common::{Command, ExitStatus, ExitCode, Stdio, StdioPipes};
pub use self::process_inner::Process;

mod process_common;
Expand Down
14 changes: 13 additions & 1 deletion src/libstd/sys/unix/process/process_common.rs
Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@ use os::unix::prelude::*;
use ffi::{OsString, OsStr, CString, CStr};
use fmt;
use io;
use libc::{self, c_int, gid_t, uid_t, c_char};
use libc::{self, c_int, gid_t, uid_t, c_char, EXIT_SUCCESS, EXIT_FAILURE};
use ptr;
use sys::fd::FileDesc;
use sys::fs::{File, OpenOptions};
Expand Down Expand Up @@ -393,6 +393,18 @@ impl fmt::Display for ExitStatus {
}
}

#[derive(PartialEq, Eq, Clone, Copy, Debug)]
pub struct ExitCode(u8);

impl ExitCode {
pub const SUCCESS: ExitCode = ExitCode(EXIT_SUCCESS as _);
pub const FAILURE: ExitCode = ExitCode(EXIT_FAILURE as _);

pub fn as_i32(&self) -> i32 {
self.0 as i32
}
}

#[cfg(all(test, not(target_os = "emscripten")))]
mod tests {
use super::*;
Expand Down
12 changes: 12 additions & 0 deletions src/libstd/sys/wasm/process.rs
Original file line number Diff line number Diff line change
Expand Up @@ -129,6 +129,18 @@ impl fmt::Display for ExitStatus {
}
}

#[derive(PartialEq, Eq, Clone, Copy, Debug)]
pub struct ExitCode(bool);

impl ExitCode {
pub const SUCCESS: ExitCode = ExitCode(false);
pub const FAILURE: ExitCode = ExitCode(true);

pub fn as_i32(&self) -> i32 {
self.0 as i32
}
}

pub struct Process(Void);

impl Process {
Expand Down
14 changes: 13 additions & 1 deletion src/libstd/sys/windows/process.rs
Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ use ffi::{OsString, OsStr};
use fmt;
use fs;
use io::{self, Error, ErrorKind};
use libc::c_void;
use libc::{c_void, EXIT_SUCCESS, EXIT_FAILURE};
use mem;
use os::windows::ffi::OsStrExt;
use path::Path;
Expand Down Expand Up @@ -408,6 +408,18 @@ impl fmt::Display for ExitStatus {
}
}

#[derive(PartialEq, Eq, Clone, Copy, Debug)]
pub struct ExitCode(c::DWORD);

impl ExitCode {
pub const SUCCESS: ExitCode = ExitCode(EXIT_SUCCESS as _);
pub const FAILURE: ExitCode = ExitCode(EXIT_FAILURE as _);

pub fn as_i32(&self) -> i32 {
self.0 as i32
}
}

fn zeroed_startupinfo() -> c::STARTUPINFO {
c::STARTUPINFO {
cb: 0,
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -14,5 +14,5 @@
use std::process::ExitCode;

fn main() -> ExitCode {
ExitCode(0)
ExitCode::SUCCESS
}