1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140

use alloc::vec::Vec;

use bitflags::bitflags;

use crate::bytesrepr;

/// The number of bytes in a serialized [`AccessRights`].
pub const ACCESS_RIGHTS_SERIALIZED_LENGTH: usize = 1;

bitflags! {
    /// A struct which behaves like a set of bitflags to define access rights associated with a
    /// [`URef`](crate::URef).
    #[allow(clippy::derive_hash_xor_eq)]
    pub struct AccessRights: u8 {
        /// No permissions
        const NONE = 0;
        /// Permission to read the value under the associated `URef`.
        const READ  = 0b001;
        /// Permission to write a value under the associated `URef`.
        const WRITE = 0b010;
        /// Permission to add to the value under the associated `URef`.
        const ADD   = 0b100;
        /// Permission to read or add to the value under the associated `URef`.
        const READ_ADD       = Self::READ.bits | Self::ADD.bits;
        /// Permission to read or write the value under the associated `URef`.
        const READ_WRITE     = Self::READ.bits | Self::WRITE.bits;
        /// Permission to add to, or write the value under the associated `URef`.
        const ADD_WRITE      = Self::ADD.bits  | Self::WRITE.bits;
        /// Permission to read, add to, or write the value under the associated `URef`.
        const READ_ADD_WRITE = Self::READ.bits | Self::ADD.bits | Self::WRITE.bits;
    }
}

impl AccessRights {
    /// Returns `true` if the `READ` flag is set.
    pub fn is_readable(self) -> bool {
        self & AccessRights::READ == AccessRights::READ
    }

    /// Returns `true` if the `WRITE` flag is set.
    pub fn is_writeable(self) -> bool {
        self & AccessRights::WRITE == AccessRights::WRITE
    }

    /// Returns `true` if the `ADD` flag is set.
    pub fn is_addable(self) -> bool {
        self & AccessRights::ADD == AccessRights::ADD
    }

    /// Returns `true` if no flags are set.
    pub fn is_none(self) -> bool {
        self == AccessRights::NONE
    }
}

impl core::fmt::Display for AccessRights {
    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
        match *self {
            AccessRights::NONE => write!(f, "NONE"),
            AccessRights::READ => write!(f, "READ"),
            AccessRights::WRITE => write!(f, "WRITE"),
            AccessRights::ADD => write!(f, "ADD"),
            AccessRights::READ_ADD => write!(f, "READ_ADD"),
            AccessRights::READ_WRITE => write!(f, "READ_WRITE"),
            AccessRights::ADD_WRITE => write!(f, "ADD_WRITE"),
            AccessRights::READ_ADD_WRITE => write!(f, "READ_ADD_WRITE"),
            _ => write!(f, "UNKNOWN"),
        }
    }
}

impl bytesrepr::ToBytes for AccessRights {
    fn to_bytes(&self) -> Result<Vec<u8>, bytesrepr::Error> {
        self.bits.to_bytes()
    }

    fn serialized_length(&self) -> usize {
        ACCESS_RIGHTS_SERIALIZED_LENGTH
    }
}

impl bytesrepr::FromBytes for AccessRights {
    fn from_bytes(bytes: &[u8]) -> Result<(Self, &[u8]), bytesrepr::Error> {
        let (id, rem) = u8::from_bytes(bytes)?;
        match AccessRights::from_bits(id) {
            Some(rights) => Ok((rights, rem)),
            None => Err(bytesrepr::Error::Formatting),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    fn test_readable(right: AccessRights, is_true: bool) {
        assert_eq!(right.is_readable(), is_true)
    }

    #[test]
    fn test_is_readable() {
        test_readable(AccessRights::READ, true);
        test_readable(AccessRights::READ_ADD, true);
        test_readable(AccessRights::READ_WRITE, true);
        test_readable(AccessRights::READ_ADD_WRITE, true);
        test_readable(AccessRights::ADD, false);
        test_readable(AccessRights::ADD_WRITE, false);
        test_readable(AccessRights::WRITE, false);
    }

    fn test_writable(right: AccessRights, is_true: bool) {
        assert_eq!(right.is_writeable(), is_true)
    }

    #[test]
    fn test_is_writable() {
        test_writable(AccessRights::WRITE, true);
        test_writable(AccessRights::READ_WRITE, true);
        test_writable(AccessRights::ADD_WRITE, true);
        test_writable(AccessRights::READ, false);
        test_writable(AccessRights::ADD, false);
        test_writable(AccessRights::READ_ADD, false);
        test_writable(AccessRights::READ_ADD_WRITE, true);
    }

    fn test_addable(right: AccessRights, is_true: bool) {
        assert_eq!(right.is_addable(), is_true)
    }

    #[test]
    fn test_is_addable() {
        test_addable(AccessRights::ADD, true);
        test_addable(AccessRights::READ_ADD, true);
        test_addable(AccessRights::READ_WRITE, false);
        test_addable(AccessRights::ADD_WRITE, true);
        test_addable(AccessRights::READ, false);
        test_addable(AccessRights::WRITE, false);
        test_addable(AccessRights::READ_ADD_WRITE, true);
    }
}