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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, PartialEq)]
pub enum Value {
String(String),
Integer(i64),
Float(f64),
Boolean(bool),
Table(HashMap<String, Value>),
Array(Vec<Value>),
}
impl Value {
/// Gets the underlying value as a string, performing a conversion only if neccessary.
#[allow(needless_lifetimes)]
pub fn as_str<'a>(&'a self) -> Option<Cow<'a, str>> {
match *self {
Value::String(ref value) => Some(Cow::Borrowed(value)),
Value::Integer(value) => Some(Cow::Owned(value.to_string())),
Value::Float(value) => Some(Cow::Owned(value.to_string())),
Value::Boolean(value) => Some(Cow::Owned(value.to_string())),
_ => None,
}
}
/// Gets the underlying type as a boolean, performing a conversion only if neccessary.
pub fn as_bool(&self) -> Option<bool> {
match *self {
Value::Boolean(value) => Some(value),
Value::Integer(value) => Some(value != 0),
Value::Float(value) => Some(value != 0.0),
Value::String(ref value) => {
match value.to_lowercase().as_ref() {
"1" | "true" | "on" | "yes" => Some(true),
"0" | "false" | "off" | "no" => Some(false),
_ => None,
}
}
_ => None,
}
}
/// Gets the underlying type as an integer, performing a conversion only if neccessary.
pub fn as_int(&self) -> Option<i64> {
match *self {
Value::Integer(value) => Some(value),
Value::String(ref value) => value.parse().ok(),
Value::Boolean(value) => Some(if value { 1 } else { 0 }),
Value::Float(value) => Some(value.round() as i64),
_ => None,
}
}
/// Gets the underlying type as a floating-point, performing a conversion only if neccessary.
pub fn as_float(&self) -> Option<f64> {
match *self {
Value::Float(value) => Some(value),
Value::String(ref value) => value.parse().ok(),
Value::Integer(value) => Some(value as f64),
Value::Boolean(value) => Some(if value { 1.0 } else { 0.0 }),
_ => None,
}
}
/// Gets the underlying type as a map; only works if the type is actually a map.
pub fn as_map(&self) -> Option<&HashMap<String, Value>> {
match *self {
Value::Table(ref value) => Some(value),
_ => None
}
}
}
// Generalized construction from type into variant is needed
// for setting configuration values
impl From<String> for Value {
fn from(value: String) -> Value {
Value::String(value.into())
}
}
impl<'a> From<&'a str> for Value {
fn from(value: &'a str) -> Value {
Value::String(value.into())
}
}
impl From<i64> for Value {
fn from(value: i64) -> Value {
Value::Integer(value)
}
}
impl From<f64> for Value {
fn from(value: f64) -> Value {
Value::Float(value)
}
}
impl From<bool> for Value {
fn from(value: bool) -> Value {
Value::Boolean(value)
}
}
impl From<HashMap<String, Value>> for Value {
fn from(value: HashMap<String, Value>) -> Value {
Value::Table(value)
}
}
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