shitbox/unix-mode/src/bit.rs

use bitflags::BitFlags;
use std::ops::{BitAnd, BitAndAssign, BitOr, BitOrAssign};

/// Unix permission bit flags
#[derive(Clone, Copy, PartialEq)]
pub enum Bit {
    Suid = 0o4000,
    Sgid = 0o2000,
    Sticky = 0o1000,
    URead = 0o400,
    UWrite = 0o200,
    UExec = 0o100,
    GRead = 0o40,
    GWrite = 0o20,
    GExec = 0o10,
    ORead = 0o4,
    OWrite = 0o2,
    OExec = 0o1,
}

impl BitAnd<u32> for Bit {
    type Output = u32;

    fn bitand(self, rhs: u32) -> Self::Output {
        self as u32 & rhs
    }
}

impl BitAnd<Bit> for u32 {
    type Output = u32;

    fn bitand(self, rhs: Bit) -> Self::Output {
        self & rhs as u32
    }
}

impl BitAnd for Bit {
    type Output = u32;

    fn bitand(self, rhs: Self) -> Self::Output {
        self as u32 & rhs as u32
    }
}

impl BitAndAssign<Bit> for u32 {
    fn bitand_assign(&mut self, rhs: Bit) {
        *self = *self & rhs;
    }
}

impl BitOr<u32> for Bit {
    type Output = u32;

    fn bitor(self, rhs: u32) -> Self::Output {
        self as u32 | rhs
    }
}

impl BitOr<Bit> for u32 {
    type Output = u32;

    fn bitor(self, rhs: Bit) -> Self::Output {
        self | rhs as u32
    }
}

impl BitOr for Bit {
    type Output = u32;

    fn bitor(self, rhs: Self) -> Self::Output {
        self as u32 | rhs as u32
    }
}

impl BitOrAssign<Bit> for u32 {
    fn bitor_assign(&mut self, rhs: Bit) {
        *self = *self | rhs;
    }
}

impl Bit {
    pub fn as_char(&self, mode: u32) -> char {
        if mode & *self != 0 {
            match self {
                Self::Suid | Self::Sgid => 's',
                Self::Sticky => 't',
                Self::URead | Self::GRead | Self::ORead => 'r',
                Self::UWrite | Self::GWrite | Self::OWrite => 'w',
                Self::UExec if mode.contains(Self::Suid) => 's',
                Self::GExec if mode.contains(Self::Sgid) => 's',
                Self::OExec if mode.contains(Self::Sticky) => 't',
                Self::UExec | Self::GExec | Self::OExec => 'x',
            }
        } else {
            '-'
        }
    }
}