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|
use proc_macro2::{Group, Span, TokenStream, TokenTree};
use std::iter::FromIterator;
use syn::visit_mut::{self, VisitMut};
use syn::{
Block, ExprPath, Ident, Item, Macro, Pat, PatIdent, PatPath, Path, Receiver, Signature, Token,
TypePath,
};
pub fn has_self_in_sig(sig: &mut Signature) -> bool {
let mut visitor = HasSelf(false);
visitor.visit_signature_mut(sig);
visitor.0
}
pub fn has_self_in_block(block: &mut Block) -> bool {
let mut visitor = HasSelf(false);
visitor.visit_block_mut(block);
visitor.0
}
fn has_self_in_token_stream(tokens: TokenStream) -> bool {
tokens.into_iter().any(|tt| match tt {
TokenTree::Ident(ident) => ident == "Self",
TokenTree::Group(group) => has_self_in_token_stream(group.stream()),
_ => false,
})
}
pub fn mut_pat(pat: &mut Pat) -> Option<Token![mut]> {
let mut visitor = HasMutPat(None);
visitor.visit_pat_mut(pat);
visitor.0
}
fn contains_fn(tokens: TokenStream) -> bool {
tokens.into_iter().any(|tt| match tt {
TokenTree::Ident(ident) => ident == "fn",
TokenTree::Group(group) => contains_fn(group.stream()),
_ => false,
})
}
struct HasMutPat(Option<Token![mut]>);
impl VisitMut for HasMutPat {
fn visit_pat_ident_mut(&mut self, i: &mut PatIdent) {
if let Some(m) = i.mutability {
self.0 = Some(m);
} else {
visit_mut::visit_pat_ident_mut(self, i);
}
}
}
struct HasSelf(bool);
impl VisitMut for HasSelf {
fn visit_expr_path_mut(&mut self, expr: &mut ExprPath) {
self.0 |= expr.path.segments[0].ident == "Self";
visit_mut::visit_expr_path_mut(self, expr);
}
fn visit_pat_path_mut(&mut self, pat: &mut PatPath) {
self.0 |= pat.path.segments[0].ident == "Self";
visit_mut::visit_pat_path_mut(self, pat);
}
fn visit_type_path_mut(&mut self, ty: &mut TypePath) {
self.0 |= ty.path.segments[0].ident == "Self";
visit_mut::visit_type_path_mut(self, ty);
}
fn visit_receiver_mut(&mut self, _arg: &mut Receiver) {
self.0 = true;
}
fn visit_item_mut(&mut self, _: &mut Item) {
// Do not recurse into nested items.
}
fn visit_macro_mut(&mut self, mac: &mut Macro) {
if !contains_fn(mac.tokens.clone()) {
self.0 |= has_self_in_token_stream(mac.tokens.clone());
}
}
}
pub struct ReplaceSelf(pub Span);
impl ReplaceSelf {
#[cfg_attr(not(self_span_hack), allow(clippy::unused_self))]
fn prepend_underscore_to_self(&self, ident: &mut Ident) -> bool {
let modified = ident == "self";
if modified {
*ident = Ident::new("__self", ident.span());
#[cfg(self_span_hack)]
ident.set_span(self.0);
}
modified
}
fn visit_token_stream(&mut self, tokens: &mut TokenStream) -> bool {
let mut out = Vec::new();
let mut modified = false;
visit_token_stream_impl(self, tokens.clone(), &mut modified, &mut out);
if modified {
*tokens = TokenStream::from_iter(out);
}
return modified;
fn visit_token_stream_impl(
visitor: &mut ReplaceSelf,
tokens: TokenStream,
modified: &mut bool,
out: &mut Vec<TokenTree>,
) {
for tt in tokens {
match tt {
TokenTree::Ident(mut ident) => {
*modified |= visitor.prepend_underscore_to_self(&mut ident);
out.push(TokenTree::Ident(ident));
}
TokenTree::Group(group) => {
let mut content = group.stream();
*modified |= visitor.visit_token_stream(&mut content);
let mut new = Group::new(group.delimiter(), content);
new.set_span(group.span());
out.push(TokenTree::Group(new));
}
other => out.push(other),
}
}
}
}
}
impl VisitMut for ReplaceSelf {
fn visit_ident_mut(&mut self, i: &mut Ident) {
self.prepend_underscore_to_self(i);
}
fn visit_path_mut(&mut self, p: &mut Path) {
if p.segments.len() == 1 {
// Replace `self`, but not `self::function`.
self.visit_ident_mut(&mut p.segments[0].ident);
}
for segment in &mut p.segments {
self.visit_path_arguments_mut(&mut segment.arguments);
}
}
fn visit_item_mut(&mut self, i: &mut Item) {
// Visit `macro_rules!` because locally defined macros can refer to
// `self`.
//
// Visit `futures::select` and similar select macros, which commonly
// appear syntactically like an item despite expanding to an expression.
//
// Otherwise, do not recurse into nested items.
if let Item::Macro(i) = i {
if i.mac.path.is_ident("macro_rules")
|| i.mac.path.segments.last().unwrap().ident == "select"
{
self.visit_macro_mut(&mut i.mac);
}
}
}
fn visit_macro_mut(&mut self, mac: &mut Macro) {
// We can't tell in general whether `self` inside a macro invocation
// refers to the self in the argument list or a different self
// introduced within the macro. Heuristic: if the macro input contains
// `fn`, then `self` is more likely to refer to something other than the
// outer function's self argument.
if !contains_fn(mac.tokens.clone()) {
self.visit_token_stream(&mut mac.tokens);
}
}
}
|
