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

use std::convert::From;
use std::collections::HashMap;
use std::borrow::Cow;

/// A configuration value.
///
/// Has an underlying or native type that comes from the configuration source
/// but will be coerced into the requested type.
#[derive(Debug, Clone)]
pub enum Value<'a> {
    String(Cow<'a, str>),
    Integer(i64),
    Float(f64),
    Boolean(bool),
    Table(HashMap<String, Value<'a>>),
    Array(Vec<Value<'a>>),
}

impl<'a> Value<'a> {
    /// Gets the underlying value as a string, performing a conversion only if neccessary.
    pub fn as_str(&'a self) -> Option<Cow<'a, str>> {
        if let Value::String(ref value) = *self {
            Some(Cow::Borrowed(&*value))
        } else if let Value::Integer(value) = *self {
            Some(Cow::Owned(value.to_string()))
        } else if let Value::Float(value) = *self {
            Some(Cow::Owned(value.to_string()))
        } else if let Value::Boolean(value) = *self {
            Some(Cow::Owned(value.to_string()))
        } else {
            None
        }
    }

    /// Gets the underlying type as a boolean, performing a conversion only if neccessary.
    pub fn as_bool(&self) -> Option<bool> {
        if let Value::Boolean(value) = *self {
            Some(value)
        } else if let Value::String(ref value) = *self {
            match value.to_lowercase().as_ref() {
                "1" | "true" | "on" | "yes" => Some(true),
                "0" | "false" | "off" | "no" => Some(false),
                _ => None,
            }
        } else if let Value::Integer(value) = *self {
            Some(value != 0)
        } else if let Value::Float(value) = *self {
            Some(value != 0.0)
        } else {
            None
        }
    }

    /// Gets the underlying type as an integer, performing a conversion only if neccessary.
    pub fn as_int(&self) -> Option<i64> {
        if let Value::Integer(value) = *self {
            Some(value)
        } else if let Value::String(ref value) = *self {
            value.parse().ok()
        } else if let Value::Boolean(value) = *self {
            Some(if value { 1 } else { 0 })
        } else if let Value::Float(value) = *self {
            Some(value.round() as i64)
        } else {
            None
        }
    }

    /// Gets the underlying type as a floating-point, performing a conversion only if neccessary.
    pub fn as_float(&self) -> Option<f64> {
        if let Value::Float(value) = *self {
            Some(value)
        } else if let Value::String(ref value) = *self {
            value.parse().ok()
        } else if let Value::Integer(value) = *self {
            Some(value as f64)
        } else if let Value::Boolean(value) = *self {
            Some(if value { 1.0 } else { 0.0 })
        } else {
            None
        }
    }
}

// Generalized construction from type into variant is needed
// for setting configuration values

impl<'a> From<String> for Value<'a> {
    fn from(value: String) -> Value<'a> {
        Value::String(value.into())
    }
}

impl<'a> From<&'a str> for Value<'a> {
    fn from(value: &'a str) -> Value<'a> {
        Value::String(value.into())
    }
}

impl<'a> From<i64> for Value<'a> {
    fn from(value: i64) -> Value<'a> {
        Value::Integer(value)
    }
}

impl<'a> From<f64> for Value<'a> {
    fn from(value: f64) -> Value<'a> {
        Value::Float(value)
    }
}

impl<'a> From<bool> for Value<'a> {
    fn from(value: bool) -> Value<'a> {
        Value::Boolean(value)
    }
}