//! The Unix `fcntl` function is effectively lots of different functions hidden

//! behind a single dynamic dispatch interface. In order to provide a type-safe

//! API, rustix makes them all separate functions so that they can have

//! dedicated static type signatures.

#[cfg(not(any(

    target_os = "emscripten",

    target_os = "espidf",

    target_os = "fuchsia",

    target_os = "redox",

    target_os = "vita",

    target_os = "wasi"

)))]

use crate::fs::FlockOperation;

use crate::{backend, io};

use backend::fd::AsFd;

use backend::fs::types::OFlags;

// These `fcntl` functions live in the `io` module because they're not specific

// to files, directories, or memfd objects. We re-export them here in the `fs`

// module because the other the `fcntl` functions are here.

#[cfg(not(any(target_os = "espidf", target_os = "wasi")))]

pub use crate::io::fcntl_dupfd_cloexec;

pub use crate::io::{fcntl_getfd, fcntl_setfd};

/// `fcntl(fd, F_GETFL)`—Returns a file descriptor's access mode and status.

///

/// # References

///  - [POSIX]

///  - [Linux]

///

/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/fcntl.html

/// [Linux]: https://man7.org/linux/man-pages/man2/fcntl.2.html

#[inline]

#[doc(alias = "F_GETFL")]

pub fn fcntl_getfl<Fd: AsFd>(fd: Fd) -> io::Result<OFlags> {

    backend::fs::syscalls::fcntl_getfl(fd.as_fd())

}

/// `fcntl(fd, F_SETFL, flags)`—Sets a file descriptor's status.

///

/// # References

///  - [POSIX]

///  - [Linux]

///

/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/fcntl.html

/// [Linux]: https://man7.org/linux/man-pages/man2/fcntl.2.html

#[inline]

#[doc(alias = "F_SETFL")]

pub fn fcntl_setfl<Fd: AsFd>(fd: Fd, flags: OFlags) -> io::Result<()> {

    backend::fs::syscalls::fcntl_setfl(fd.as_fd(), flags)

}

/// `fcntl(fd, F_GET_SEALS)`

///

/// # References

///  - [Linux]

///

/// [Linux]: https://man7.org/linux/man-pages/man2/fcntl.2.html

#[cfg(any(linux_kernel, target_os = "freebsd", target_os = "fuchsia"))]

#[inline]

#[doc(alias = "F_GET_SEALS")]

pub fn fcntl_get_seals<Fd: AsFd>(fd: Fd) -> io::Result<SealFlags> {

    backend::fs::syscalls::fcntl_get_seals(fd.as_fd())

}

#[cfg(any(linux_kernel, target_os = "freebsd", target_os = "fuchsia"))]

use backend::fs::types::SealFlags;

/// `fcntl(fd, F_ADD_SEALS)`

///

/// # References

///  - [Linux]

///

/// [Linux]: https://man7.org/linux/man-pages/man2/fcntl.2.html

#[cfg(any(linux_kernel, target_os = "freebsd", target_os = "fuchsia"))]

#[inline]

#[doc(alias = "F_ADD_SEALS")]

pub fn fcntl_add_seals<Fd: AsFd>(fd: Fd, seals: SealFlags) -> io::Result<()> {

    backend::fs::syscalls::fcntl_add_seals(fd.as_fd(), seals)

}

/// `fcntl(fd, F_SETLK)`—Acquire or release an `fcntl`-style lock.

///

/// This function doesn't currently have an offset or len; it currently always

/// sets the `l_len` field to 0, which is a special case that means the entire

/// file should be locked.

///

/// Unlike `flock`-style locks, `fcntl`-style locks are process-associated,

/// meaning that they don't guard against being acquired by two threads in the

/// same process.

///

/// # References

///  - [POSIX]

///  - [Linux]

///

/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/fcntl.html

/// [Linux]: https://man7.org/linux/man-pages/man2/fcntl.2.html

#[cfg(not(any(

    target_os = "emscripten",

    target_os = "espidf",

    target_os = "fuchsia",

    target_os = "redox",

    target_os = "vita",

    target_os = "wasi"

)))]

#[inline]

#[doc(alias = "F_SETLK")]

#[doc(alias = "F_SETLKW")]

pub fn fcntl_lock<Fd: AsFd>(fd: Fd, operation: FlockOperation) -> io::Result<()> {

    backend::fs::syscalls::fcntl_lock(fd.as_fd(), operation)

}