|
| 1 | +use proc_macro2::Span; |
| 2 | +use proc_macro_error::emit_error; |
| 3 | +use std::sync::{Arc, Mutex}; |
| 4 | +use syn::spanned::Spanned; |
| 5 | +use syn::visit_mut::VisitMut; |
| 6 | +use syn::{ |
| 7 | + parse_quote_spanned, visit_mut, Expr, ExprCall, ExprClosure, ExprForLoop, ExprIf, ExprLoop, |
| 8 | + ExprMatch, ExprWhile, Ident, Item, |
| 9 | +}; |
| 10 | + |
| 11 | +#[derive(Debug, Default)] |
| 12 | +pub struct BodyRewriter { |
| 13 | + branch_lock: Arc<Mutex<()>>, |
| 14 | +} |
| 15 | + |
| 16 | +impl BodyRewriter { |
| 17 | + fn is_branched(&self) -> bool { |
| 18 | + self.branch_lock.try_lock().is_err() |
| 19 | + } |
| 20 | + |
| 21 | + fn with_branch<F, O>(&mut self, f: F) -> O |
| 22 | + where |
| 23 | + F: FnOnce(&mut BodyRewriter) -> O, |
| 24 | + { |
| 25 | + let branch_lock = self.branch_lock.clone(); |
| 26 | + let _branched = branch_lock.try_lock(); |
| 27 | + f(self) |
| 28 | + } |
| 29 | +} |
| 30 | + |
| 31 | +impl VisitMut for BodyRewriter { |
| 32 | + fn visit_expr_call_mut(&mut self, i: &mut ExprCall) { |
| 33 | + let ctx_ident = Ident::new("ctx", Span::mixed_site()); |
| 34 | + |
| 35 | + // Only rewrite hook calls. |
| 36 | + if let Expr::Path(ref m) = &*i.func { |
| 37 | + if let Some(m) = m.path.segments.last().as_ref().map(|m| &m.ident) { |
| 38 | + if m.to_string().starts_with("use_") { |
| 39 | + if self.is_branched() { |
| 40 | + emit_error!( |
| 41 | + m, |
| 42 | + "hooks cannot be called at this position."; |
| 43 | + help = "move hooks to the top-level of your function."; |
| 44 | + note = "see: https://yew.rs/docs/next/concepts/function-components/introduction#hooks" |
| 45 | + ); |
| 46 | + } else { |
| 47 | + *i = parse_quote_spanned! { i.span() => ::yew::functional::Hook::run(#i, #ctx_ident) }; |
| 48 | + } |
| 49 | + |
| 50 | + return; |
| 51 | + } |
| 52 | + } |
| 53 | + } |
| 54 | + |
| 55 | + visit_mut::visit_expr_call_mut(self, i); |
| 56 | + } |
| 57 | + |
| 58 | + fn visit_expr_closure_mut(&mut self, i: &mut ExprClosure) { |
| 59 | + self.with_branch(move |m| visit_mut::visit_expr_closure_mut(m, i)) |
| 60 | + } |
| 61 | + |
| 62 | + fn visit_expr_if_mut(&mut self, i: &mut ExprIf) { |
| 63 | + for it in &mut i.attrs { |
| 64 | + visit_mut::visit_attribute_mut(self, it); |
| 65 | + } |
| 66 | + |
| 67 | + visit_mut::visit_expr_mut(self, &mut *i.cond); |
| 68 | + |
| 69 | + self.with_branch(|m| visit_mut::visit_block_mut(m, &mut i.then_branch)); |
| 70 | + |
| 71 | + if let Some(it) = &mut i.else_branch { |
| 72 | + self.with_branch(|m| visit_mut::visit_expr_mut(m, &mut *(it).1)); |
| 73 | + } |
| 74 | + } |
| 75 | + |
| 76 | + fn visit_expr_loop_mut(&mut self, i: &mut ExprLoop) { |
| 77 | + self.with_branch(|m| visit_mut::visit_expr_loop_mut(m, i)); |
| 78 | + } |
| 79 | + |
| 80 | + fn visit_expr_for_loop_mut(&mut self, i: &mut ExprForLoop) { |
| 81 | + for it in &mut i.attrs { |
| 82 | + visit_mut::visit_attribute_mut(self, it); |
| 83 | + } |
| 84 | + if let Some(it) = &mut i.label { |
| 85 | + visit_mut::visit_label_mut(self, it); |
| 86 | + } |
| 87 | + visit_mut::visit_pat_mut(self, &mut i.pat); |
| 88 | + visit_mut::visit_expr_mut(self, &mut *i.expr); |
| 89 | + |
| 90 | + self.with_branch(|m| visit_mut::visit_block_mut(m, &mut i.body)); |
| 91 | + } |
| 92 | + |
| 93 | + fn visit_expr_match_mut(&mut self, i: &mut ExprMatch) { |
| 94 | + for it in &mut i.attrs { |
| 95 | + visit_mut::visit_attribute_mut(self, it); |
| 96 | + } |
| 97 | + |
| 98 | + visit_mut::visit_expr_mut(self, &mut *i.expr); |
| 99 | + |
| 100 | + self.with_branch(|m| { |
| 101 | + for it in &mut i.arms { |
| 102 | + visit_mut::visit_arm_mut(m, it); |
| 103 | + } |
| 104 | + }); |
| 105 | + } |
| 106 | + |
| 107 | + fn visit_expr_while_mut(&mut self, i: &mut ExprWhile) { |
| 108 | + for it in &mut i.attrs { |
| 109 | + visit_mut::visit_attribute_mut(self, it); |
| 110 | + } |
| 111 | + if let Some(it) = &mut i.label { |
| 112 | + visit_mut::visit_label_mut(self, it); |
| 113 | + } |
| 114 | + |
| 115 | + self.with_branch(|m| visit_mut::visit_expr_mut(m, &mut i.cond)); |
| 116 | + self.with_branch(|m| visit_mut::visit_block_mut(m, &mut i.body)); |
| 117 | + } |
| 118 | + |
| 119 | + fn visit_item_mut(&mut self, _i: &mut Item) { |
| 120 | + // We don't do anything for items. |
| 121 | + // for components / hooks in other components / hooks, apply the attribute again. |
| 122 | + } |
| 123 | +} |
0 commit comments