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use std::iter::Peekable;
use proc_macro2::{Delimiter, Ident, Span, TokenStream, TokenTree};
pub fn get_ident<T: AsRef<str>>(name: T) -> Ident {
Ident::new(name.as_ref(), Span::call_site())
}
pub fn stream_to_string(vec: Vec<TokenTree>) -> String {
let mut stream = TokenStream::new();
stream.extend(vec.into_iter());
stream.to_string()
}
pub fn get_after_impl(vec: &[TokenTree]) -> Vec<TokenTree> {
let mut index = 0;
vec.iter().enumerate().for_each(|(inner_index, value)| {
if let TokenTree::Ident(ident) = value {
if ident == &get_ident("impl") {
index = inner_index;
}
}
});
let slice = &vec[index..];
slice.to_vec()
}
pub fn loc_trait_impl(name: &str, code: TokenStream, impl_for: Option<&str>) -> Option<String> {
fn find_after_for(
iter: &mut Peekable<impl Iterator<Item = TokenTree>>,
collection: &mut Vec<TokenTree>,
impl_for: Option<&str>,
) -> Option<String> {
while let Some(token) = iter.peek() {
match token {
TokenTree::Ident(ident) if ident == &get_ident("for") => {
if let Some(struct_ident) = impl_for {
collection.push(iter.next().unwrap());
if let Some(next_ident) = iter.peek() {
match next_ident {
TokenTree::Ident(next_ident) => {
if next_ident != struct_ident {
return None;
}
}
_ => return None,
}
}
}
while let Some(token) = iter.peek() {
match token {
TokenTree::Group(group) if group.delimiter() == Delimiter::Brace => {
let mut stream = TokenStream::new();
// UNWRAP: iter.peek() is some
collection.push(iter.next().unwrap());
stream.extend(get_after_impl(collection).into_iter());
return Some(stream.to_string());
}
// UNWRAP: iter.peek() is some
_ => collection.push(iter.next().unwrap()),
}
}
}
// UNWRAP: iter.peek() is some
_ => collection.push(iter.next().unwrap()),
}
}
None
}
let mut iter = code.into_iter().peekable();
while let Some(tree) = iter.next() {
match tree {
TokenTree::Group(group) => {
if let Some(string) = loc_trait_impl(name, group.stream(), impl_for) {
return Some(string);
}
}
TokenTree::Ident(ref ident) => {
if ident == &get_ident("impl") {
let mut collection = vec![tree];
while let Some(x) = iter.peek() {
match x {
TokenTree::Ident(ident) if ident == &get_ident(name) => {
if let Some(x) =
find_after_for(&mut iter, &mut collection, impl_for)
{
return Some(x);
}
}
// UNWRAP: iter.peek() is some
_ => collection.push(iter.next().unwrap()),
}
}
}
}
_ => (),
}
}
None
}
pub fn loc_struct(name: &str, code: TokenStream) -> Option<String> {
let mut iter = code.into_iter().peekable();
while let Some(tree) = iter.next() {
match tree {
TokenTree::Group(group) => {
if let Some(string) = loc_struct(name, group.stream()) {
return Some(string);
}
}
TokenTree::Ident(ref ident) => {
if ident == &get_ident("struct") {
if let Some(TokenTree::Ident(ident)) = iter.peek() {
if ident == &get_ident(name) {
let clone = ident.clone();
iter.next();
let mut collection = vec![tree, TokenTree::Ident(clone)];
for x in iter.by_ref() {
if let TokenTree::Group(_) = x {
collection.push(x);
return Some(stream_to_string(collection));
}
collection.push(x);
}
}
}
}
}
_ => (),
}
}
None
}
pub fn loc_function(name: &str, code: TokenStream) -> Option<String> {
let mut iter = code.into_iter().peekable();
while let Some(tree) = iter.next() {
match tree {
TokenTree::Group(group) => {
if let Some(string) = loc_function(name, group.stream()) {
return Some(string);
}
}
TokenTree::Ident(ref ident) => {
if ident == &get_ident("fn") {
if let Some(TokenTree::Ident(ident)) = iter.peek() {
if ident == &get_ident(name) {
let clone = ident.clone();
iter.next();
let mut collection = vec![tree, TokenTree::Ident(clone)];
for x in iter.by_ref() {
if let TokenTree::Group(ref grp) = x {
let delimiter = grp.delimiter();
collection.push(x);
// check if we arrived at the function body
if delimiter == Delimiter::Brace {
return Some(stream_to_string(collection));
}
} else {
collection.push(x);
}
}
}
}
}
}
_ => (),
}
}
None
}