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use std::borrow::Cow;
use std::collections::HashMap;
use proc_macro2::{Ident, Span};
use syn::{parse_quote, Expr};
use crate::parse::Fixture;
pub(crate) fn fixture_resolver<'a>(
fixtures: impl Iterator<Item = &'a Fixture>,
) -> impl Resolver + 'a {
fixtures
.map(|f| (f.name.to_string(), extract_resolve_expression(f).into()))
.collect::<HashMap<_, Expr>>()
}
pub(crate) trait Resolver {
fn resolve(&self, ident: &Ident) -> Option<Cow<Expr>>;
}
impl<'a> Resolver for HashMap<String, &'a Expr> {
fn resolve(&self, ident: &Ident) -> Option<Cow<Expr>> {
let ident = ident.to_string();
self.get(&ident).map(|&c| Cow::Borrowed(c))
}
}
impl<'a> Resolver for HashMap<String, Expr> {
fn resolve(&self, ident: &Ident) -> Option<Cow<Expr>> {
let ident = ident.to_string();
self.get(&ident).map(|c| Cow::Borrowed(c))
}
}
impl<R1: Resolver, R2: Resolver> Resolver for (R1, R2) {
fn resolve(&self, ident: &Ident) -> Option<Cow<Expr>> {
self.0.resolve(ident).or_else(|| self.1.resolve(ident))
}
}
impl<R: Resolver + ?Sized> Resolver for &R {
fn resolve(&self, ident: &Ident) -> Option<Cow<Expr>> {
(*self).resolve(ident)
}
}
impl<R: Resolver + ?Sized> Resolver for Box<R> {
fn resolve(&self, ident: &Ident) -> Option<Cow<Expr>> {
(**self).resolve(ident)
}
}
impl Resolver for (String, Expr) {
fn resolve(&self, ident: &Ident) -> Option<Cow<Expr>> {
if self.0 == ident.to_string() {
Some(Cow::Borrowed(&self.1))
} else {
None
}
}
}
fn extract_resolve_expression(fixture: &Fixture) -> syn::Expr {
let name = &fixture.name;
let positional = &fixture.positional;
let pname = format!("partial_{}", positional.len());
let partial = Ident::new(&pname, Span::call_site());
parse_quote! { #name::#partial(#(#positional), *) }
}
#[cfg(test)]
mod should {
use super::*;
use crate::test::{assert_eq, *};
use syn::parse_str;
#[test]
fn return_the_given_expression() {
let ast = parse_str("fn function(mut foo: String) {}").unwrap();
let arg = first_arg_ident(&ast);
let expected = expr("bar()");
let mut resolver = HashMap::new();
resolver.insert("foo".to_string(), &expected);
assert_eq!(expected, (&resolver).resolve(&arg).unwrap().into_owned())
}
#[test]
fn return_none_for_unknown_argument() {
let ast = "fn function(mut fix: String) {}".ast();
let arg = first_arg_ident(&ast);
assert!(EmptyResolver.resolve(&arg).is_none())
}
}