libnv 0.5.0

Safe and rustic wrapper around libnv-sys.
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// #![deny(missing_docs)]

//! Rust bindings to Name/Value pairs libraries [libnv] and [nvpair]
//! It kinda acts like `Map<&str, T>` for poor people.
//! Library split into two modules: `libnv` and `nvpairs`. `libnv` is FreeBSD implementation that
//! isn't compatible with `nvpairs` that is Solaris implementation.
//!
//! [libnv]: https://www.freebsd.org/cgi/man.cgi?query=nv
//! [nvpair]: https://github.com/zfsonlinux/zfs/tree/master/module/nvpair

#![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]

#[cfg(feature = "libnv")] pub mod libnv;

#[cfg(feature = "nvpair")] pub mod nvpair;

use std::{borrow::Cow,
          ffi::{CStr, CString, NulError},
          io};

use quick_error::quick_error;

quick_error! {
    #[derive(Debug)]
    /// Error kinds for Name/Value library.
    pub enum NvError {
        /// Name a.k.a. key can't contain NULL byte. You going to get this error if you try so.
        InvalidString(err: NulError) {
            from()
        }
        /// error return by ffi. See libc for more information.
        NativeError(code: i32) {}
        /// Trying to set an error on n/v list that already has error
        AlreadySet {}
        /// No value found for given name.
        NotFound {}
        /// Library failed to allocate.
        OutOfMemory {}
        /// Other IO errors
        Io(err: io::Error) {}
        /// Operation not support on a list given flags used to create the list.
        OperationNotSupported {}
        /// Got non-utf8 string from the library.
        InvalidStringEncoding(err: std::str::Utf8Error) {
            from()
        }
    }
}
impl NvError {
    pub(crate) fn from_errno(errno: i32) -> Self {
        match errno {
            libc::ENOENT => NvError::NotFound,
            libc::ENOMEM => NvError::OutOfMemory,
            libc::EOPNOTSUPP => NvError::OperationNotSupported,
            n => NvError::Io(io::Error::from_raw_os_error(n)),
        }
    }
}

/// Short-cut to Result<T, NvError>.
pub type NvResult<T> = Result<T, NvError>;

/// Trait to keep public interface friendly (i.e. support rust types like `&str`) and at the same
/// time allow using lower level types like `CString` & `CStr`.
pub trait IntoCStr<'a> {
    fn into_c_str(self) -> NvResult<Cow<'a, CStr>>;
}

impl<'a> IntoCStr<'a> for &'a CStr {
    fn into_c_str(self) -> NvResult<Cow<'a, CStr>> { Ok(Cow::from(self)) }
}

impl<'a> IntoCStr<'a> for CString {
    fn into_c_str(self) -> NvResult<Cow<'a, CStr>> { Ok(Cow::from(self)) }
}

impl<'a> IntoCStr<'a> for &str {
    fn into_c_str(self) -> NvResult<Cow<'a, CStr>> {
        CString::new(self).map(Cow::from).map_err(NvError::from)
    }
}

impl<'a> IntoCStr<'a> for String {
    fn into_c_str(self) -> NvResult<Cow<'a, CStr>> {
        CString::new(self).map(Cow::from).map_err(NvError::from)
    }
}