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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)
}
}
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