concurrency.rs.html -- source
Description: Source to the Rust file `library/test/src/helpers/concurrency.rs`.
Keywords: rust, rustlang, rust-lang

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    //! Helper module which helps to determine amount of threads to be used
    //! during tests execution.
    use std::env;

    #[allow(deprecated)]
    pub fn get_concurrency() -> usize {
        match env::var("RUST_TEST_THREADS") {
            Ok(s) => {
                let opt_n: Option<usize> = s.parse().ok();
                match opt_n {
                    Some(n) if n > 0 => n,
                    _ => panic!("RUST_TEST_THREADS is `{}`, should be a positive integer.", s),
                }
            }
            Err(..) => num_cpus(),
        }
    }

    cfg_if::cfg_if! {
        if #[cfg(windows)] {
            #[allow(nonstandard_style)]
            fn num_cpus() -> usize {
                #[repr(C)]
                struct SYSTEM_INFO {
                    wProcessorArchitecture: u16,
                    wReserved: u16,
                    dwPageSize: u32,
                    lpMinimumApplicationAddress: *mut u8,
                    lpMaximumApplicationAddress: *mut u8,
                    dwActiveProcessorMask: *mut u8,
                    dwNumberOfProcessors: u32,
                    dwProcessorType: u32,
                    dwAllocationGranularity: u32,
                    wProcessorLevel: u16,
                    wProcessorRevision: u16,
                }
                extern "system" {
                    fn GetSystemInfo(info: *mut SYSTEM_INFO) -> i32;
                }
                unsafe {
                    let mut sysinfo = std::mem::zeroed();
                    GetSystemInfo(&mut sysinfo);
                    sysinfo.dwNumberOfProcessors as usize
                }
            }
        } else if #[cfg(any(
            target_os = "android",
            target_os = "cloudabi",
            target_os = "emscripten",
            target_os = "fuchsia",
            target_os = "ios",
            target_os = "linux",
            target_os = "macos",
            target_os = "solaris",
            target_os = "illumos",
        ))] {
            fn num_cpus() -> usize {
                unsafe { libc::sysconf(libc::_SC_NPROCESSORS_ONLN) as usize }
            }
        } else if #[cfg(any(target_os = "freebsd", target_os = "dragonfly", target_os = "netbsd"))] {
            fn num_cpus() -> usize {
                use std::ptr;

                let mut cpus: libc::c_uint = 0;
                let mut cpus_size = std::mem::size_of_val(&cpus);

                unsafe {
                    cpus = libc::sysconf(libc::_SC_NPROCESSORS_ONLN) as libc::c_uint;
                }
                if cpus < 1 {
                    let mut mib = [libc::CTL_HW, libc::HW_NCPU, 0, 0];
                    unsafe {
                        libc::sysctl(
                            mib.as_mut_ptr(),
                            2,
                            &mut cpus as *mut _ as *mut _,
                            &mut cpus_size as *mut _ as *mut _,
                            ptr::null_mut(),
                            0,
                        );
                    }
                    if cpus < 1 {
                        cpus = 1;
                    }
                }
                cpus as usize
            }
        } else if #[cfg(target_os = "openbsd")] {
            fn num_cpus() -> usize {
                use std::ptr;

                let mut cpus: libc::c_uint = 0;
                let mut cpus_size = std::mem::size_of_val(&cpus);
                let mut mib = [libc::CTL_HW, libc::HW_NCPU, 0, 0];

                unsafe {
                    libc::sysctl(
                        mib.as_mut_ptr(),
                        2,
                        &mut cpus as *mut _ as *mut _,
                        &mut cpus_size as *mut _ as *mut _,
                        ptr::null_mut(),
                        0,
                    );
                }
                if cpus < 1 {
                    cpus = 1;
                }
                cpus as usize
            }
        } else {
            // FIXME: implement on vxWorks, Redox, HermitCore, Haiku, l4re
            fn num_cpus() -> usize {
                1
            }
        }
    }