use itertools::Itertools;
use serde::{
de::{MapAccess, Visitor},
Deserialize, Deserializer,
};
use std::{
collections::{hash_map::Keys, HashMap},
fmt,
sync::Arc,
};
#[derive(Default, Debug, PartialEq)]
pub struct StrMap(pub(crate) Arc<HashMap<String, Vec<String>>>);
impl StrMap {
pub fn get(&self, key: &str) -> Option<&str> {
self.0
.get(key)
.and_then(|values| values.first().map(|owned| owned.as_str()))
}
pub fn get_all(&self, key: &str) -> Option<Vec<&str>> {
self.0
.get(key)
.map(|values| values.iter().map(|owned| owned.as_str()).collect::<Vec<_>>())
}
pub fn is_empty(&self) -> bool {
self.0.is_empty()
}
pub fn iter(&self) -> StrMapIter<'_> {
StrMapIter {
data: self,
keys: self.0.keys(),
}
}
}
impl Clone for StrMap {
fn clone(&self) -> Self {
StrMap(self.0.clone())
}
}
impl From<HashMap<String, Vec<String>>> for StrMap {
fn from(inner: HashMap<String, Vec<String>>) -> Self {
StrMap(Arc::new(inner))
}
}
impl From<HashMap<String, String>> for StrMap {
fn from(inner: HashMap<String, String>) -> Self {
StrMap(Arc::new(inner.into_iter().into_group_map()))
}
}
pub struct StrMapIter<'a> {
data: &'a StrMap,
keys: Keys<'a, String, Vec<String>>,
}
impl<'a> Iterator for StrMapIter<'a> {
type Item = (&'a str, &'a str);
#[inline]
fn next(&mut self) -> Option<(&'a str, &'a str)> {
self.keys.next().and_then(|k| self.data.get(k).map(|v| (k.as_str(), v)))
}
}
#[derive(Deserialize)]
#[serde(untagged)]
enum OneOrMany {
One(String),
Many(Vec<String>),
}
impl<'de> Deserialize<'de> for StrMap {
fn deserialize<D>(deserializer: D) -> Result<StrMap, D::Error>
where
D: Deserializer<'de>,
{
struct StrMapVisitor;
impl<'de> Visitor<'de> for StrMapVisitor {
type Value = StrMap;
fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(formatter, "a StrMap")
}
fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error>
where
A: MapAccess<'de>,
{
let mut inner = map.size_hint().map(HashMap::with_capacity).unwrap_or_else(HashMap::new);
while let Some((key, value)) = map.next_entry::<_, OneOrMany>()? {
inner.insert(
key,
match value {
OneOrMany::One(one) => vec![one],
OneOrMany::Many(many) => many,
},
);
}
Ok(StrMap(Arc::new(inner)))
}
}
deserializer.deserialize_map(StrMapVisitor)
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::collections::HashMap;
#[test]
fn str_map_default_is_empty() {
assert!(StrMap::default().is_empty())
}
#[test]
fn str_map_get() {
let mut data = HashMap::new();
data.insert("foo".into(), vec!["bar".into()]);
let strmap = StrMap(data.into());
assert_eq!(strmap.get("foo"), Some("bar"));
assert_eq!(strmap.get("bar"), None);
}
#[test]
fn str_map_get_all() {
let mut data = HashMap::new();
data.insert("foo".into(), vec!["bar".into(), "baz".into()]);
let strmap = StrMap(data.into());
assert_eq!(strmap.get_all("foo"), Some(vec!["bar", "baz"]));
assert_eq!(strmap.get_all("bar"), None);
}
#[test]
fn str_map_iter() {
let mut data = HashMap::new();
data.insert("foo".into(), vec!["bar".into()]);
data.insert("baz".into(), vec!["boom".into()]);
let strmap = StrMap(data.into());
let mut values = strmap.iter().map(|(_, v)| v).collect::<Vec<_>>();
values.sort();
assert_eq!(values, vec!["bar", "boom"]);
}
}