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use fidl_fuchsia_diagnostics::Selector;
use selectors::{parse_selector, selector_to_string, VerboseError};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use thiserror::Error;
#[derive(Error, Debug, PartialEq)]
pub enum MappingError {
#[error("List match was unbounded or contained cycles")]
Unbounded,
#[error("map_selector was attempted but converting the input to a string failed: {0}")]
BadInputSelector(String),
#[error(
"map_selector was attempted but the source mapping list contains an invalid selector: {0}. Error was: {1}"
)]
BadSelector(String, String),
}
#[derive(Debug, Default, Deserialize, Serialize)]
pub struct MappingList {
#[serde(flatten)]
mappings: HashMap<String, String>,
}
impl MappingList {
pub fn new(mappings: HashMap<String, String>) -> Self {
Self { mappings }
}
pub fn map(&self, input: &str) -> Result<String, MappingError> {
let mut result = input.to_string();
let limit = self.mappings.len();
let mut count = 0;
while let Some(new_result) = self.mappings.get(&result) {
result = new_result.clone();
count += 1;
if count > limit {
return Err(MappingError::Unbounded);
}
}
Ok(result)
}
}
#[derive(Debug, Default, Deserialize, Serialize)]
pub struct SelectorMappingList {
#[serde(flatten)]
mappings: MappingList,
}
impl SelectorMappingList {
pub fn new(mappings: HashMap<String, String>) -> Self {
Self { mappings: MappingList::new(mappings) }
}
pub fn map_selector(&self, input: Selector) -> Result<Selector, MappingError> {
if let Ok(selector_str) = selector_to_string(input.clone()) {
match self.mappings.map(&selector_str) {
Ok(mapped_selector) => parse_selector::<VerboseError>(&mapped_selector)
.map_err(|e| MappingError::BadSelector(mapped_selector, format!("{:?}", e))),
Err(e) => Err(e),
}
} else {
Err(MappingError::BadInputSelector(format!("{:?}", input)))
}
}
}
#[cfg(test)]
mod test {
use super::*;
use assert_matches::assert_matches;
fn tup_to_map(items: Vec<(&str, &str)>) -> HashMap<String, String> {
items.iter().map(|s| (s.0.to_string(), s.1.to_string())).collect()
}
#[test]
fn map_list_one_matching_entry() {
let list =
MappingList::new(tup_to_map(vec![("apples", "oranges"), ("bananas", "strawberries")]));
assert_eq!(list.map("bananas"), Ok("strawberries".to_string()))
}
#[test]
fn map_list_no_matching_entries() {
let list =
MappingList::new(tup_to_map(vec![("apples", "oranges"), ("bananas", "strawberries")]));
assert_eq!(list.map("blueberries"), Ok("blueberries".to_string()))
}
#[test]
fn map_list_maps_recursively() {
let list =
MappingList::new(tup_to_map(vec![("oranges", "strawberries"), ("apples", "oranges")]));
assert_eq!(list.map("apples"), Ok("strawberries".to_string()))
}
#[test]
fn map_list_returns_unbounded_error_on_cycles() {
let list = MappingList::new(tup_to_map(vec![("oranges", "apples"), ("apples", "oranges")]));
assert_matches!(list.map("apples"), Err(MappingError::Unbounded))
}
#[test]
fn selector_map_with_matching_entries() {
let list = SelectorMappingList::new(tup_to_map(vec![
("oranges:apples:bananas", "apples:bananas:oranges"),
("a:b:c", "c:b:a"),
]));
assert_eq!(
list.map_selector(parse_selector::<VerboseError>("oranges:apples:bananas").unwrap())
.unwrap(),
parse_selector::<VerboseError>("apples:bananas:oranges").unwrap()
)
}
#[test]
fn selector_map_with_broken_entry() {
let list = SelectorMappingList::new(tup_to_map(vec![
("oranges:apples:bananas", "not_real::::::"),
("a:b:c", "c:b:a"),
]));
match list
.map_selector(parse_selector::<VerboseError>("oranges:apples:bananas").unwrap())
.unwrap_err()
{
MappingError::BadSelector(s, _) => {
assert_eq!(s, String::from("not_real::::::"))
}
e => panic!("unexpected error type {:?}", e),
}
}
}