// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! Experimental extensions to `std` for Unix platforms.
//!
//! For now, this module is limited to extracting file descriptors,
//! but its functionality will grow over time.
//!
//! # Example
//!
//! ```rust,ignore
//! #![feature(globs)]
//!
//! use std::old_io::fs::File;
//! use std::os::unix::prelude::*;
//!
//! fn main() {
//!     let f = File::create(&Path::new("foo.txt")).unwrap();
//!     let fd = f.as_raw_fd();
//!
//!     // use fd with native unix bindings
//! }
//! ```

#![unstable(feature = "std_misc")]

use prelude::v1::*;

use ffi::{CString, NulError, OsStr, OsString};
use fs::{self, Permissions, OpenOptions};
use net;
use mem;
use process;
use sys;
use sys::os_str::Buf;
use sys_common::{AsInner, AsInnerMut, IntoInner, FromInner};
use libc::{self, gid_t, uid_t};

use old_io;

/// Raw file descriptors.
pub type Fd = libc::c_int;

/// Extract raw file descriptor
pub trait AsRawFd {
    /// Extract the raw file descriptor, without taking any ownership.
    fn as_raw_fd(&self) -> Fd;
}

impl AsRawFd for old_io::fs::File {
    fn as_raw_fd(&self) -> Fd {
        self.as_inner().fd()
    }
}

impl AsRawFd for fs::File {
    fn as_raw_fd(&self) -> Fd {
        self.as_inner().fd().raw()
    }
}

impl AsRawFd for old_io::pipe::PipeStream {
    fn as_raw_fd(&self) -> Fd {
        self.as_inner().fd()
    }
}

impl AsRawFd for old_io::net::pipe::UnixStream {
    fn as_raw_fd(&self) -> Fd {
        self.as_inner().fd()
    }
}

impl AsRawFd for old_io::net::pipe::UnixListener {
    fn as_raw_fd(&self) -> Fd {
        self.as_inner().fd()
    }
}

impl AsRawFd for old_io::net::pipe::UnixAcceptor {
    fn as_raw_fd(&self) -> Fd {
        self.as_inner().fd()
    }
}

impl AsRawFd for old_io::net::tcp::TcpStream {
    fn as_raw_fd(&self) -> Fd {
        self.as_inner().fd()
    }
}

impl AsRawFd for old_io::net::tcp::TcpListener {
    fn as_raw_fd(&self) -> Fd {
        self.as_inner().fd()
    }
}

impl AsRawFd for old_io::net::tcp::TcpAcceptor {
    fn as_raw_fd(&self) -> Fd {
        self.as_inner().fd()
    }
}

impl AsRawFd for old_io::net::udp::UdpSocket {
    fn as_raw_fd(&self) -> Fd {
        self.as_inner().fd()
    }
}

impl AsRawFd for net::TcpStream {
    fn as_raw_fd(&self) -> Fd { *self.as_inner().socket().as_inner() }
}
impl AsRawFd for net::TcpListener {
    fn as_raw_fd(&self) -> Fd { *self.as_inner().socket().as_inner() }
}
impl AsRawFd for net::UdpSocket {
    fn as_raw_fd(&self) -> Fd { *self.as_inner().socket().as_inner() }
}

////////////////////////////////////////////////////////////////////////////////
// OsString and OsStr
////////////////////////////////////////////////////////////////////////////////

/// Unix-specific extensions to `OsString`.
pub trait OsStringExt {
    /// Create an `OsString` from a byte vector.
    fn from_vec(vec: Vec<u8>) -> Self;

    /// Yield the underlying byte vector of this `OsString`.
    fn into_vec(self) -> Vec<u8>;
}

impl OsStringExt for OsString {
    fn from_vec(vec: Vec<u8>) -> OsString {
        FromInner::from_inner(Buf { inner: vec })
    }

    fn into_vec(self) -> Vec<u8> {
        self.into_inner().inner
    }
}

/// Unix-specific extensions to `OsStr`.
pub trait OsStrExt {
    fn from_bytes(slice: &[u8]) -> &OsStr;

    /// Get the underlying byte view of the `OsStr` slice.
    fn as_bytes(&self) -> &[u8];

    /// Convert the `OsStr` slice into a `CString`.
    fn to_cstring(&self) -> Result<CString, NulError>;
}

impl OsStrExt for OsStr {
    fn from_bytes(slice: &[u8]) -> &OsStr {
        unsafe { mem::transmute(slice) }
    }
    fn as_bytes(&self) -> &[u8] {
        &self.as_inner().inner
    }

    fn to_cstring(&self) -> Result<CString, NulError> {
        CString::new(self.as_bytes())
    }
}

// Unix-specific extensions to `Permissions`
pub trait PermissionsExt {
    fn mode(&self) -> i32;
    fn set_mode(&mut self, mode: i32);
}

impl PermissionsExt for Permissions {
    fn mode(&self) -> i32 { self.as_inner().mode() }

    fn set_mode(&mut self, mode: i32) {
        *self = FromInner::from_inner(FromInner::from_inner(mode));
    }
}

// Unix-specific extensions to `OpenOptions`
pub trait OpenOptionsExt {
    /// Set the mode bits that a new file will be created with.
    ///
    /// If a new file is created as part of a `File::open_opts` call then this
    /// specified `mode` will be used as the permission bits for the new file.
    fn mode(&mut self, mode: i32) -> &mut Self;
}

impl OpenOptionsExt for OpenOptions {
    fn mode(&mut self, mode: i32) -> &mut OpenOptions {
        self.as_inner_mut().mode(mode); self
    }
}

////////////////////////////////////////////////////////////////////////////////
// Process and Command
////////////////////////////////////////////////////////////////////////////////

/// Unix-specific extensions to the `std::process::Command` builder
pub trait CommandExt {
    /// Sets the child process's user id. This translates to a
    /// `setuid` call in the child process. Failure in the `setuid`
    /// call will cause the spawn to fail.
    fn uid(&mut self, id: uid_t) -> &mut process::Command;

    /// Similar to `uid`, but sets the group id of the child process. This has
    /// the same semantics as the `uid` field.
    fn gid(&mut self, id: gid_t) -> &mut process::Command;
}

impl CommandExt for process::Command {
    fn uid(&mut self, id: uid_t) -> &mut process::Command {
        self.as_inner_mut().uid = Some(id);
        self
    }

    fn gid(&mut self, id: gid_t) -> &mut process::Command {
        self.as_inner_mut().gid = Some(id);
        self
    }
}

/// Unix-specific extensions to `std::process::ExitStatus`
pub trait ExitStatusExt {
    /// If the process was terminated by a signal, returns that signal.
    fn signal(&self) -> Option<i32>;
}

impl ExitStatusExt for process::ExitStatus {
    fn signal(&self) -> Option<i32> {
        match *self.as_inner() {
            sys::process2::ExitStatus::Signal(s) => Some(s),
            _ => None
        }
    }
}

////////////////////////////////////////////////////////////////////////////////
// Prelude
////////////////////////////////////////////////////////////////////////////////

/// A prelude for conveniently writing platform-specific code.
///
/// Includes all extension traits, and some important type definitions.
pub mod prelude {
    #[doc(no_inline)]
    pub use super::{Fd, AsRawFd, OsStrExt, OsStringExt, PermissionsExt};
    #[doc(no_inline)]
    pub use super::{CommandExt, ExitStatusExt};
}