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

/// An enum offering the choice between inherited and included resources.
///
/// This is a private module used only internally.

use std::fmt;
use std::str::FromStr;
use crate::x509::ValidationError;


//------------ ResourcesChoice -----------------------------------------------

/// The option to either include or inherit resources.
///
/// This is generic over the type of included resources.
#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
pub enum ResourcesChoice<T> {
    /// Resources are to be inherited from the issuer.
    Inherit,

    /// The resources are provided as a set of blocks.
    Blocks(T),
}

impl<T> ResourcesChoice<T> {
    /// Returns whether the resources are of the inherited variant.
    pub fn is_inherited(&self) -> bool {
        match self {
            ResourcesChoice::Inherit => true,
            _ =>  false
        }
    }

    /// Returns a reference to the blocks if there are any.
    pub fn as_blocks(&self) -> Option<&T> {
        match self {
            ResourcesChoice::Inherit => None,
            ResourcesChoice::Blocks(ref some) => Some(some)
        }
    }

    /// Returns a mutable reference to the blocks if there are any.
    pub fn as_blocks_mut(&mut self) -> Option<&mut T> {
        match self {
            ResourcesChoice::Inherit => None,
            ResourcesChoice::Blocks(ref mut some) => Some(some)
        }
    }

    /// Converts the resources into blocks or returns an error.
    pub fn to_blocks(&self) -> Result<T, ValidationError>
    where T: Clone {
        match self {
            ResourcesChoice::Inherit => Err(ValidationError),
            ResourcesChoice::Blocks(ref some) => Ok(some.clone()),
        }
    }

    /// Converts the choice into a different choice via a closure.
    ///
    /// If this value is of the included variant, runs the blocks through
    /// the provided closure and returns a new choice with the result. If
    /// this value is of the inherit variant, does nothing and simply
    /// returns the choice.
    pub fn map_blocks<U, F>(self, f: F) -> ResourcesChoice<U>
    where F: FnOnce(T) -> U {
        match self {
            ResourcesChoice::Inherit => ResourcesChoice::Inherit,
            ResourcesChoice::Blocks(t) => ResourcesChoice::Blocks(f(t))
        }
    }
}


//--- Display

impl<T: fmt::Display> fmt::Display for ResourcesChoice<T> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            ResourcesChoice::Inherit => write!(f, "inherit"),
            ResourcesChoice::Blocks(ref inner) => inner.fmt(f)
        }
    }
}

//--- FromStr

impl<T: FromStr> FromStr for ResourcesChoice<T> {
    type Err = FromStrErr;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        if s == "inherit" {
            Ok(ResourcesChoice::Inherit)
        } else {
            let blocks = T::from_str(s).map_err(|_| FromStrErr::BlocksFromStr)?;
            Ok(ResourcesChoice::Blocks(blocks))
        }
    }
}

//------------ FromStrError --------------------------------------------------

#[derive(Clone, Debug, Display, Eq, PartialEq)]
pub enum FromStrErr {
    #[display(fmt="Cannot parse blocks")]
    BlocksFromStr,
}