microsoft-webui-dev-server 3.0.2

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.

#![allow(unsafe_code)]

use std::io;
use std::mem::{size_of, zeroed};
use std::os::windows::io::{AsRawHandle, FromRawHandle, OwnedHandle};
use std::os::windows::process::CommandExt;
use std::process::{Child, Command};
use windows_sys::Win32::System::JobObjects::{
    AssignProcessToJobObject, CreateJobObjectW, JobObjectExtendedLimitInformation,
    SetInformationJobObject, TerminateJobObject, JOBOBJECT_EXTENDED_LIMIT_INFORMATION,
    JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE,
};
use windows_sys::Win32::System::Threading::CREATE_NEW_PROCESS_GROUP;

pub(super) struct Scope(OwnedHandle);

impl Scope {
    pub(super) fn new() -> io::Result<Self> {
        // SAFETY: Null security attributes create an unnamed, non-inherited job.
        let raw = unsafe { CreateJobObjectW(std::ptr::null(), std::ptr::null()) };
        if raw.is_null() {
            return Err(io::Error::last_os_error());
        }
        // SAFETY: raw is a freshly created valid handle, transferred exactly once.
        let job = unsafe { OwnedHandle::from_raw_handle(raw) };
        // SAFETY: This Win32 C structure permits all-zero initialization.
        let mut info: JOBOBJECT_EXTENDED_LIMIT_INFORMATION = unsafe { zeroed() };
        info.BasicLimitInformation.LimitFlags = JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE;
        // SAFETY: The job handle and structure remain valid through the call.
        let result = unsafe {
            SetInformationJobObject(
                job.as_raw_handle(),
                JobObjectExtendedLimitInformation,
                std::ptr::addr_of!(info).cast(),
                u32::try_from(size_of::<JOBOBJECT_EXTENDED_LIMIT_INFORMATION>())
                    .map_err(io::Error::other)?,
            )
        };
        if result == 0 {
            return Err(io::Error::last_os_error());
        }
        Ok(Self(job))
    }

    pub(super) fn configure(&self, command: &mut Command) {
        command.creation_flags(CREATE_NEW_PROCESS_GROUP);
    }

    pub(super) fn attach(&mut self, child: &Child) -> io::Result<()> {
        // SAFETY: Both handles are owned and valid; the child's startup gate
        // prevents writers or descendants until after successful assignment.
        let result =
            unsafe { AssignProcessToJobObject(self.0.as_raw_handle(), child.as_raw_handle()) };
        if result == 0 {
            return Err(io::Error::last_os_error());
        }
        Ok(())
    }

    pub(super) fn terminate(&self, _child: &Child) -> io::Result<()> {
        // SAFETY: The job contains only the gated child and its descendants.
        if unsafe { TerminateJobObject(self.0.as_raw_handle(), 1) } == 0 {
            return Err(io::Error::last_os_error());
        }
        Ok(())
    }
}