//! Get filesystem statistics, non-portably
//!
//! See [`statvfs`](crate::sys::statvfs) for a portable alternative.
#[cfg(not(any(target_os = "linux", target_os = "android")))]
use std::ffi::CStr;
use std::fmt::{self, Debug};
use std::mem;
use std::os::unix::io::{AsFd, AsRawFd};

use cfg_if::cfg_if;

#[cfg(all(
    feature = "mount",
    any(
        target_os = "dragonfly",
        target_os = "freebsd",
        target_os = "macos",
        target_os = "netbsd",
        target_os = "openbsd"
    )
))]
use crate::mount::MntFlags;
#[cfg(target_os = "linux")]
use crate::sys::statvfs::FsFlags;
use crate::{errno::Errno, NixPath, Result};

/// Identifies a mounted file system
#[cfg(target_os = "android")]
#[cfg_attr(docsrs, doc(cfg(all())))]
pub type fsid_t = libc::__fsid_t;
/// Identifies a mounted file system
#[cfg(not(target_os = "android"))]
#[cfg_attr(docsrs, doc(cfg(all())))]
pub type fsid_t = libc::fsid_t;

cfg_if! {
    if #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))] {
        type type_of_statfs = libc::statfs64;
        const LIBC_FSTATFS: unsafe extern fn
            (fd: libc::c_int, buf: *mut type_of_statfs) -> libc::c_int
            = libc::fstatfs64;
        const LIBC_STATFS: unsafe extern fn
            (path: *const libc::c_char, buf: *mut type_of_statfs) -> libc::c_int
            = libc::statfs64;
    } else {
        type type_of_statfs = libc::statfs;
        const LIBC_FSTATFS: unsafe extern fn
            (fd: libc::c_int, buf: *mut type_of_statfs) -> libc::c_int
            = libc::fstatfs;
        const LIBC_STATFS: unsafe extern fn
            (path: *const libc::c_char, buf: *mut type_of_statfs) -> libc::c_int
            = libc::statfs;
    }
}

/// Describes a mounted file system
#[derive(Clone, Copy)]
#[repr(transparent)]
pub struct Statfs(type_of_statfs);

#[cfg(target_os = "freebsd")]
type fs_type_t = u32;
#[cfg(target_os = "android")]
type fs_type_t = libc::c_ulong;
#[cfg(all(target_os = "linux", target_arch = "s390x"))]
type fs_type_t = libc::c_uint;
#[cfg(all(target_os = "linux", target_env = "musl"))]
type fs_type_t = libc::c_ulong;
#[cfg(all(target_os = "linux", target_env = "uclibc"))]
type fs_type_t = libc::c_int;
#[cfg(all(
    target_os = "linux",
    not(any(
        target_arch = "s390x",
        target_env = "musl",
        target_env = "uclibc"
    ))
))]
type fs_type_t = libc::__fsword_t;

/// Describes the file system type as known by the operating system.
#[cfg(any(
    target_os = "freebsd",
    target_os = "android",
    all(target_os = "linux", target_arch = "s390x"),
    all(target_os = "linux", target_env = "musl"),
    all(
        target_os = "linux",
        not(any(target_arch = "s390x", target_env = "musl"))
    ),
))]
#[derive(Eq, Copy, Clone, PartialEq, Debug)]
pub struct FsType(pub fs_type_t);

// These constants are defined without documentation in the Linux headers, so we
// can't very well document them here.
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const ADFS_SUPER_MAGIC: FsType =
    FsType(libc::ADFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const AFFS_SUPER_MAGIC: FsType =
    FsType(libc::AFFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const AFS_SUPER_MAGIC: FsType = FsType(libc::AFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const AUTOFS_SUPER_MAGIC: FsType =
    FsType(libc::AUTOFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const BPF_FS_MAGIC: FsType = FsType(libc::BPF_FS_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const BTRFS_SUPER_MAGIC: FsType =
    FsType(libc::BTRFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const CGROUP2_SUPER_MAGIC: FsType =
    FsType(libc::CGROUP2_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const CGROUP_SUPER_MAGIC: FsType =
    FsType(libc::CGROUP_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const CODA_SUPER_MAGIC: FsType =
    FsType(libc::CODA_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const CRAMFS_MAGIC: FsType = FsType(libc::CRAMFS_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const DEBUGFS_MAGIC: FsType = FsType(libc::DEBUGFS_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const DEVPTS_SUPER_MAGIC: FsType =
    FsType(libc::DEVPTS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const ECRYPTFS_SUPER_MAGIC: FsType =
    FsType(libc::ECRYPTFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const EFS_SUPER_MAGIC: FsType = FsType(libc::EFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const EXT2_SUPER_MAGIC: FsType =
    FsType(libc::EXT2_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const EXT3_SUPER_MAGIC: FsType =
    FsType(libc::EXT3_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const EXT4_SUPER_MAGIC: FsType =
    FsType(libc::EXT4_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const F2FS_SUPER_MAGIC: FsType =
    FsType(libc::F2FS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const FUSE_SUPER_MAGIC: FsType =
    FsType(libc::FUSE_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const FUTEXFS_SUPER_MAGIC: FsType =
    FsType(libc::FUTEXFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const HOSTFS_SUPER_MAGIC: FsType =
    FsType(libc::HOSTFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const HPFS_SUPER_MAGIC: FsType =
    FsType(libc::HPFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const HUGETLBFS_MAGIC: FsType = FsType(libc::HUGETLBFS_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const ISOFS_SUPER_MAGIC: FsType =
    FsType(libc::ISOFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const JFFS2_SUPER_MAGIC: FsType =
    FsType(libc::JFFS2_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const MINIX2_SUPER_MAGIC2: FsType =
    FsType(libc::MINIX2_SUPER_MAGIC2 as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const MINIX2_SUPER_MAGIC: FsType =
    FsType(libc::MINIX2_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const MINIX3_SUPER_MAGIC: FsType =
    FsType(libc::MINIX3_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const MINIX_SUPER_MAGIC2: FsType =
    FsType(libc::MINIX_SUPER_MAGIC2 as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const MINIX_SUPER_MAGIC: FsType =
    FsType(libc::MINIX_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const MSDOS_SUPER_MAGIC: FsType =
    FsType(libc::MSDOS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const NCP_SUPER_MAGIC: FsType = FsType(libc::NCP_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const NFS_SUPER_MAGIC: FsType = FsType(libc::NFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const NILFS_SUPER_MAGIC: FsType =
    FsType(libc::NILFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const OCFS2_SUPER_MAGIC: FsType =
    FsType(libc::OCFS2_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const OPENPROM_SUPER_MAGIC: FsType =
    FsType(libc::OPENPROM_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const OVERLAYFS_SUPER_MAGIC: FsType =
    FsType(libc::OVERLAYFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const PROC_SUPER_MAGIC: FsType =
    FsType(libc::PROC_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const QNX4_SUPER_MAGIC: FsType =
    FsType(libc::QNX4_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const QNX6_SUPER_MAGIC: FsType =
    FsType(libc::QNX6_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const RDTGROUP_SUPER_MAGIC: FsType =
    FsType(libc::RDTGROUP_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const REISERFS_SUPER_MAGIC: FsType =
    FsType(libc::REISERFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const SECURITYFS_MAGIC: FsType =
    FsType(libc::SECURITYFS_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const SELINUX_MAGIC: FsType = FsType(libc::SELINUX_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const SMACK_MAGIC: FsType = FsType(libc::SMACK_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const SMB_SUPER_MAGIC: FsType = FsType(libc::SMB_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const SYSFS_MAGIC: FsType = FsType(libc::SYSFS_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const TMPFS_MAGIC: FsType = FsType(libc::TMPFS_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const TRACEFS_MAGIC: FsType = FsType(libc::TRACEFS_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const UDF_SUPER_MAGIC: FsType = FsType(libc::UDF_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const USBDEVICE_SUPER_MAGIC: FsType =
    FsType(libc::USBDEVICE_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const XENFS_SUPER_MAGIC: FsType =
    FsType(libc::XENFS_SUPER_MAGIC as fs_type_t);
#[cfg(any(target_os = "linux", target_os = "android"))]
#[allow(missing_docs)]
pub const NSFS_MAGIC: FsType = FsType(libc::NSFS_MAGIC as fs_type_t);
#[cfg(all(
    any(target_os = "linux", target_os = "android"),
    not(target_env = "musl")
))]
#[allow(missing_docs)]
pub const XFS_SUPER_MAGIC: FsType = FsType(libc::XFS_SUPER_MAGIC as fs_type_t);

impl Statfs {
    /// Magic code defining system type
    #[cfg(not(any(
        target_os = "openbsd",
        target_os = "dragonfly",
        target_os = "ios",
        target_os = "macos"
    )))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn filesystem_type(&self) -> FsType {
        FsType(self.0.f_type)
    }

    /// Magic code defining system type
    #[cfg(not(any(target_os = "linux", target_os = "android")))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn filesystem_type_name(&self) -> &str {
        let c_str = unsafe { CStr::from_ptr(self.0.f_fstypename.as_ptr()) };
        c_str.to_str().unwrap()
    }

    /// Optimal transfer block size
    #[cfg(any(target_os = "ios", target_os = "macos"))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn optimal_transfer_size(&self) -> i32 {
        self.0.f_iosize
    }

    /// Optimal transfer block size
    #[cfg(target_os = "openbsd")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn optimal_transfer_size(&self) -> u32 {
        self.0.f_iosize
    }

    /// Optimal transfer block size
    #[cfg(all(target_os = "linux", target_arch = "s390x"))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn optimal_transfer_size(&self) -> u32 {
        self.0.f_bsize
    }

    /// Optimal transfer block size
    #[cfg(any(
        target_os = "android",
        all(target_os = "linux", target_env = "musl")
    ))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn optimal_transfer_size(&self) -> libc::c_ulong {
        self.0.f_bsize
    }

    /// Optimal transfer block size
    #[cfg(all(
        target_os = "linux",
        not(any(
            target_arch = "s390x",
            target_env = "musl",
            target_env = "uclibc"
        ))
    ))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn optimal_transfer_size(&self) -> libc::__fsword_t {
        self.0.f_bsize
    }

    /// Optimal transfer block size
    #[cfg(all(target_os = "linux", target_env = "uclibc"))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn optimal_transfer_size(&self) -> libc::c_int {
        self.0.f_bsize
    }

    /// Optimal transfer block size
    #[cfg(target_os = "dragonfly")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn optimal_transfer_size(&self) -> libc::c_long {
        self.0.f_iosize
    }

    /// Optimal transfer block size
    #[cfg(target_os = "freebsd")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn optimal_transfer_size(&self) -> u64 {
        self.0.f_iosize
    }

    /// Size of a block
    #[cfg(any(target_os = "ios", target_os = "macos", target_os = "openbsd"))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn block_size(&self) -> u32 {
        self.0.f_bsize
    }

    /// Size of a block
    // f_bsize on linux: https://github.com/torvalds/linux/blob/master/fs/nfs/super.c#L471
    #[cfg(all(target_os = "linux", target_arch = "s390x"))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn block_size(&self) -> u32 {
        self.0.f_bsize
    }

    /// Size of a block
    // f_bsize on linux: https://github.com/torvalds/linux/blob/master/fs/nfs/super.c#L471
    #[cfg(all(target_os = "linux", target_env = "musl"))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn block_size(&self) -> libc::c_ulong {
        self.0.f_bsize
    }

    /// Size of a block
    // f_bsize on linux: https://github.com/torvalds/linux/blob/master/fs/nfs/super.c#L471
    #[cfg(all(target_os = "linux", target_env = "uclibc"))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn block_size(&self) -> libc::c_int {
        self.0.f_bsize
    }

    /// Size of a block
    // f_bsize on linux: https://github.com/torvalds/linux/blob/master/fs/nfs/super.c#L471
    #[cfg(all(
        target_os = "linux",
        not(any(
            target_arch = "s390x",
            target_env = "musl",
            target_env = "uclibc"
        ))
    ))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn block_size(&self) -> libc::__fsword_t {
        self.0.f_bsize
    }

    /// Size of a block
    #[cfg(target_os = "freebsd")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn block_size(&self) -> u64 {
        self.0.f_bsize
    }

    /// Size of a block
    #[cfg(target_os = "android")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn block_size(&self) -> libc::c_ulong {
        self.0.f_bsize
    }

    /// Size of a block
    #[cfg(target_os = "dragonfly")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn block_size(&self) -> libc::c_long {
        self.0.f_bsize
    }

    /// Get the mount flags
    #[cfg(all(
        feature = "mount",
        any(
            target_os = "dragonfly",
            target_os = "freebsd",
            target_os = "macos",
            target_os = "netbsd",
            target_os = "openbsd"
        )
    ))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    #[allow(clippy::unnecessary_cast)] // Not unnecessary on all arches
    pub fn flags(&self) -> MntFlags {
        MntFlags::from_bits_truncate(self.0.f_flags as i32)
    }

    /// Get the mount flags
    // The f_flags field exists on Android and Fuchsia too, but without man
    // pages I can't tell if it can be cast to FsFlags.
    #[cfg(target_os = "linux")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn flags(&self) -> FsFlags {
        FsFlags::from_bits_truncate(self.0.f_flags as libc::c_ulong)
    }

    /// Maximum length of filenames
    #[cfg(any(target_os = "freebsd", target_os = "openbsd"))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn maximum_name_length(&self) -> u32 {
        self.0.f_namemax
    }

    /// Maximum length of filenames
    #[cfg(all(target_os = "linux", target_arch = "s390x"))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn maximum_name_length(&self) -> u32 {
        self.0.f_namelen
    }

    /// Maximum length of filenames
    #[cfg(all(target_os = "linux", target_env = "musl"))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn maximum_name_length(&self) -> libc::c_ulong {
        self.0.f_namelen
    }

    /// Maximum length of filenames
    #[cfg(all(target_os = "linux", target_env = "uclibc"))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn maximum_name_length(&self) -> libc::c_int {
        self.0.f_namelen
    }

    /// Maximum length of filenames
    #[cfg(all(
        target_os = "linux",
        not(any(
            target_arch = "s390x",
            target_env = "musl",
            target_env = "uclibc"
        ))
    ))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn maximum_name_length(&self) -> libc::__fsword_t {
        self.0.f_namelen
    }

    /// Maximum length of filenames
    #[cfg(target_os = "android")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn maximum_name_length(&self) -> libc::c_ulong {
        self.0.f_namelen
    }

    /// Total data blocks in filesystem
    #[cfg(any(
        target_os = "ios",
        target_os = "macos",
        target_os = "android",
        target_os = "freebsd",
        target_os = "fuchsia",
        target_os = "openbsd",
        target_os = "linux",
    ))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn blocks(&self) -> u64 {
        self.0.f_blocks
    }

    /// Total data blocks in filesystem
    #[cfg(target_os = "dragonfly")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn blocks(&self) -> libc::c_long {
        self.0.f_blocks
    }

    /// Total data blocks in filesystem
    #[cfg(target_os = "emscripten")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn blocks(&self) -> u32 {
        self.0.f_blocks
    }

    /// Free blocks in filesystem
    #[cfg(any(
        target_os = "ios",
        target_os = "macos",
        target_os = "android",
        target_os = "freebsd",
        target_os = "fuchsia",
        target_os = "openbsd",
        target_os = "linux",
    ))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn blocks_free(&self) -> u64 {
        self.0.f_bfree
    }

    /// Free blocks in filesystem
    #[cfg(target_os = "dragonfly")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn blocks_free(&self) -> libc::c_long {
        self.0.f_bfree
    }

    /// Free blocks in filesystem
    #[cfg(target_os = "emscripten")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn blocks_free(&self) -> u32 {
        self.0.f_bfree
    }

    /// Free blocks available to unprivileged user
    #[cfg(any(
        target_os = "ios",
        target_os = "macos",
        target_os = "android",
        target_os = "fuchsia",
        target_os = "linux",
    ))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn blocks_available(&self) -> u64 {
        self.0.f_bavail
    }

    /// Free blocks available to unprivileged user
    #[cfg(target_os = "dragonfly")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn blocks_available(&self) -> libc::c_long {
        self.0.f_bavail
    }

    /// Free blocks available to unprivileged user
    #[cfg(any(target_os = "freebsd", target_os = "openbsd"))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn blocks_available(&self) -> i64 {
        self.0.f_bavail
    }

    /// Free blocks available to unprivileged user
    #[cfg(target_os = "emscripten")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn blocks_available(&self) -> u32 {
        self.0.f_bavail
    }

    /// Total file nodes in filesystem
    #[cfg(any(
        target_os = "ios",
        target_os = "macos",
        target_os = "android",
        target_os = "freebsd",
        target_os = "fuchsia",
        target_os = "openbsd",
        target_os = "linux",
    ))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn files(&self) -> u64 {
        self.0.f_files
    }

    /// Total file nodes in filesystem
    #[cfg(target_os = "dragonfly")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn files(&self) -> libc::c_long {
        self.0.f_files
    }

    /// Total file nodes in filesystem
    #[cfg(target_os = "emscripten")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn files(&self) -> u32 {
        self.0.f_files
    }

    /// Free file nodes in filesystem
    #[cfg(any(
        target_os = "ios",
        target_os = "macos",
        target_os = "android",
        target_os = "fuchsia",
        target_os = "openbsd",
        target_os = "linux",
    ))]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn files_free(&self) -> u64 {
        self.0.f_ffree
    }

    /// Free file nodes in filesystem
    #[cfg(target_os = "dragonfly")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn files_free(&self) -> libc::c_long {
        self.0.f_ffree
    }

    /// Free file nodes in filesystem
    #[cfg(target_os = "freebsd")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn files_free(&self) -> i64 {
        self.0.f_ffree
    }

    /// Free file nodes in filesystem
    #[cfg(target_os = "emscripten")]
    #[cfg_attr(docsrs, doc(cfg(all())))]
    pub fn files_free(&self) -> u32 {
        self.0.f_ffree
    }

    /// Filesystem ID
    pub fn filesystem_id(&self) -> fsid_t {
        self.0.f_fsid
    }
}

impl Debug for Statfs {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let mut ds = f.debug_struct("Statfs");
        ds.field("optimal_transfer_size", &self.optimal_transfer_size());
        ds.field("block_size", &self.block_size());
        ds.field("blocks", &self.blocks());
        ds.field("blocks_free", &self.blocks_free());
        ds.field("blocks_available", &self.blocks_available());
        ds.field("files", &self.files());
        ds.field("files_free", &self.files_free());
        ds.field("filesystem_id", &self.filesystem_id());
        #[cfg(all(
            feature = "mount",
            any(
                target_os = "dragonfly",
                target_os = "freebsd",
                target_os = "macos",
                target_os = "netbsd",
                target_os = "openbsd"
            )
        ))]
        ds.field("flags", &self.flags());
        ds.finish()
    }
}

/// Describes a mounted file system.
///
/// The result is OS-dependent.  For a portable alternative, see
/// [`statvfs`](crate::sys::statvfs::statvfs).
///
/// # Arguments
///
/// `path` - Path to any file within the file system to describe
pub fn statfs<P: ?Sized + NixPath>(path: &P) -> Result<Statfs> {
    unsafe {
        let mut stat = mem::MaybeUninit::<type_of_statfs>::uninit();
        let res = path.with_nix_path(|path| {
            LIBC_STATFS(path.as_ptr(), stat.as_mut_ptr())
        })?;
        Errno::result(res).map(|_| Statfs(stat.assume_init()))
    }
}

/// Describes a mounted file system.
///
/// The result is OS-dependent.  For a portable alternative, see
/// [`fstatvfs`](crate::sys::statvfs::fstatvfs).
///
/// # Arguments
///
/// `fd` - File descriptor of any open file within the file system to describe
pub fn fstatfs<Fd: AsFd>(fd: Fd) -> Result<Statfs> {
    unsafe {
        let mut stat = mem::MaybeUninit::<type_of_statfs>::uninit();
        Errno::result(LIBC_FSTATFS(fd.as_fd().as_raw_fd(), stat.as_mut_ptr()))
            .map(|_| Statfs(stat.assume_init()))
    }
}

#[cfg(test)]
mod test {
    use std::fs::File;

    use crate::sys::statfs::*;
    use crate::sys::statvfs::*;
    use std::path::Path;

    #[test]
    fn statfs_call() {
        check_statfs("/tmp");
        check_statfs("/dev");
        check_statfs("/run");
        check_statfs("/");
    }

    #[test]
    fn fstatfs_call() {
        check_fstatfs("/tmp");
        check_fstatfs("/dev");
        check_fstatfs("/run");
        check_fstatfs("/");
    }

    fn check_fstatfs(path: &str) {
        if !Path::new(path).exists() {
            return;
        }
        let vfs = statvfs(path.as_bytes()).unwrap();
        let file = File::open(path).unwrap();
        let fs = fstatfs(&file).unwrap();
        assert_fs_equals(fs, vfs);
    }

    fn check_statfs(path: &str) {
        if !Path::new(path).exists() {
            return;
        }
        let vfs = statvfs(path.as_bytes()).unwrap();
        let fs = statfs(path.as_bytes()).unwrap();
        assert_fs_equals(fs, vfs);
    }

    // The cast is not unnecessary on all platforms.
    #[allow(clippy::unnecessary_cast)]
    fn assert_fs_equals(fs: Statfs, vfs: Statvfs) {
        assert_eq!(fs.files() as u64, vfs.files() as u64);
        assert_eq!(fs.blocks() as u64, vfs.blocks() as u64);
        assert_eq!(fs.block_size() as u64, vfs.fragment_size() as u64);
    }

    // This test is ignored because files_free/blocks_free can change after statvfs call and before
    // statfs call.
    #[test]
    #[ignore]
    fn statfs_call_strict() {
        check_statfs_strict("/tmp");
        check_statfs_strict("/dev");
        check_statfs_strict("/run");
        check_statfs_strict("/");
    }

    // This test is ignored because files_free/blocks_free can change after statvfs call and before
    // fstatfs call.
    #[test]
    #[ignore]
    fn fstatfs_call_strict() {
        check_fstatfs_strict("/tmp");
        check_fstatfs_strict("/dev");
        check_fstatfs_strict("/run");
        check_fstatfs_strict("/");
    }

    fn check_fstatfs_strict(path: &str) {
        if !Path::new(path).exists() {
            return;
        }
        let vfs = statvfs(path.as_bytes());
        let file = File::open(path).unwrap();
        let fs = fstatfs(&file);
        assert_fs_equals_strict(fs.unwrap(), vfs.unwrap())
    }

    fn check_statfs_strict(path: &str) {
        if !Path::new(path).exists() {
            return;
        }
        let vfs = statvfs(path.as_bytes());
        let fs = statfs(path.as_bytes());
        assert_fs_equals_strict(fs.unwrap(), vfs.unwrap())
    }

    // The cast is not unnecessary on all platforms.
    #[allow(clippy::unnecessary_cast)]
    fn assert_fs_equals_strict(fs: Statfs, vfs: Statvfs) {
        assert_eq!(fs.files_free() as u64, vfs.files_free() as u64);
        assert_eq!(fs.blocks_free() as u64, vfs.blocks_free() as u64);
        assert_eq!(fs.blocks_available() as u64, vfs.blocks_available() as u64);
        assert_eq!(fs.files() as u64, vfs.files() as u64);
        assert_eq!(fs.blocks() as u64, vfs.blocks() as u64);
        assert_eq!(fs.block_size() as u64, vfs.fragment_size() as u64);
    }
}