x-path 0.1.0-alpha.0

x-path is a if-it-compiles-it-works solution for safe Rust paths with abs/rel and file/dir variants for API safety and cross platform support
Documentation 
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use std::env;
use std::ffi::{CStr, OsString};
use std::mem;
use std::os::unix::ffi::OsStringExt;
use std::path::PathBuf;
use std::ptr;

#[allow(dead_code)]
// https://github.com/rust-lang/rust/blob/2682b88c526d493edeb2d3f2df358f44db69b73f/library/std/src/sys/unix/os.rs#L595
pub fn home_dir() -> Option<PathBuf> {
    return env::var_os("HOME")
        .and_then(|h| if h.is_empty() { None } else { Some(h) })
        .or_else(|| unsafe { fallback() })
        .map(PathBuf::from);

    #[cfg(any(target_os = "android", target_os = "ios", target_os = "emscripten"))]
    unsafe fn fallback() -> Option<OsString> {
        None
    }
    #[cfg(not(any(target_os = "android", target_os = "ios", target_os = "emscripten")))]
    unsafe fn fallback() -> Option<OsString> {
        let amt = match libc::sysconf(libc::_SC_GETPW_R_SIZE_MAX) {
            n if n < 0 => 512 as usize,
            n => n as usize,
        };
        let mut buf = Vec::with_capacity(amt);
        let mut passwd: libc::passwd = mem::zeroed();
        let mut result = ptr::null_mut();
        match libc::getpwuid_r(
            libc::getuid(),
            &mut passwd,
            buf.as_mut_ptr(),
            buf.capacity(),
            &mut result,
        ) {
            0 if !result.is_null() => {
                let ptr = passwd.pw_dir as *const _;
                let bytes = CStr::from_ptr(ptr).to_bytes();
                if bytes.is_empty() {
                    None
                } else {
                    Some(OsStringExt::from_vec(bytes.to_vec()))
                }
            }
            _ => None,
        }
    }
}