1 // SPDX-License-Identifier: GPL-2.0
2
3 use proc_macro::{token_stream, Group, TokenStr
4
5 pub(crate) fn try_ident(it: &mut token_stream:
6 if let Some(TokenTree::Ident(ident)) = it.
7 Some(ident.to_string())
8 } else {
9 None
10 }
11 }
12
13 pub(crate) fn try_literal(it: &mut token_strea
14 if let Some(TokenTree::Literal(literal)) =
15 Some(literal.to_string())
16 } else {
17 None
18 }
19 }
20
21 pub(crate) fn try_string(it: &mut token_stream
22 try_literal(it).and_then(|string| {
23 if string.starts_with('\"') && string.
24 let content = &string[1..string.le
25 if content.contains('\\') {
26 panic!("Escape sequences in st
27 }
28 Some(content.to_string())
29 } else if string.starts_with("r\"") {
30 panic!("Raw string literals are no
31 } else {
32 None
33 }
34 })
35 }
36
37 pub(crate) fn expect_ident(it: &mut token_stre
38 try_ident(it).expect("Expected Ident")
39 }
40
41 pub(crate) fn expect_punct(it: &mut token_stre
42 if let TokenTree::Punct(punct) = it.next()
43 punct.as_char()
44 } else {
45 panic!("Expected Punct");
46 }
47 }
48
49 pub(crate) fn expect_string(it: &mut token_str
50 try_string(it).expect("Expected string")
51 }
52
53 pub(crate) fn expect_string_ascii(it: &mut tok
54 let string = try_string(it).expect("Expect
55 assert!(string.is_ascii(), "Expected ASCII
56 string
57 }
58
59 pub(crate) fn expect_group(it: &mut token_stre
60 if let TokenTree::Group(group) = it.next()
61 group
62 } else {
63 panic!("Expected Group");
64 }
65 }
66
67 pub(crate) fn expect_end(it: &mut token_stream
68 if it.next().is_some() {
69 panic!("Expected end");
70 }
71 }
72
73 /// Parsed generics.
74 ///
75 /// See the field documentation for an explana
76 ///
77 /// # Examples
78 ///
79 /// ```rust,ignore
80 /// # let input = todo!();
81 /// let (Generics { decl_generics, impl_generi
82 /// quote! {
83 /// struct Foo<$($decl_generics)*> {
84 /// // ...
85 /// }
86 ///
87 /// impl<$impl_generics> Foo<$ty_generics>
88 /// fn foo() {
89 /// // ...
90 /// }
91 /// }
92 /// }
93 /// ```
94 pub(crate) struct Generics {
95 /// The generics with bounds and default v
96 ///
97 /// Use this on type definitions e.g. `str
98 pub(crate) decl_generics: Vec<TokenTree>,
99 /// The generics with bounds (e.g. `T: Clo
100 ///
101 /// Use this on `impl` blocks e.g. `impl<$
102 pub(crate) impl_generics: Vec<TokenTree>,
103 /// The generics without bounds and withou
104 ///
105 /// Use this when you use the type that is
106 /// `Foo<$ty_generics>`.
107 pub(crate) ty_generics: Vec<TokenTree>,
108 }
109
110 /// Parses the given `TokenStream` into `Gener
111 ///
112 /// The generics are not present in the rest,
113 pub(crate) fn parse_generics(input: TokenStrea
114 // The generics with bounds and default va
115 let mut decl_generics = vec![];
116 // `impl_generics`, the declared generics
117 let mut impl_generics = vec![];
118 // Only the names of the generics, without
119 let mut ty_generics = vec![];
120 // Tokens not related to the generics e.g.
121 let mut rest = vec![];
122 // The current level of `<`.
123 let mut nesting = 0;
124 let mut toks = input.into_iter();
125 // If we are at the beginning of a generic
126 let mut at_start = true;
127 let mut skip_until_comma = false;
128 while let Some(tt) = toks.next() {
129 if nesting == 1 && matches!(&tt, Token
130 // Found the end of the generics.
131 break;
132 } else if nesting >= 1 {
133 decl_generics.push(tt.clone());
134 }
135 match tt.clone() {
136 TokenTree::Punct(p) if p.as_char()
137 if nesting >= 1 && !skip_until
138 // This is inside of the g
139 impl_generics.push(tt);
140 }
141 nesting += 1;
142 }
143 TokenTree::Punct(p) if p.as_char()
144 // This is a parsing error, so
145 if nesting == 0 {
146 break;
147 } else {
148 nesting -= 1;
149 if nesting >= 1 && !skip_u
150 // We are still inside
151 impl_generics.push(tt)
152 }
153 }
154 }
155 TokenTree::Punct(p) if skip_until_
156 if nesting == 1 {
157 impl_generics.push(tt.clon
158 impl_generics.push(tt);
159 skip_until_comma = false;
160 }
161 }
162 _ if !skip_until_comma => {
163 match nesting {
164 // If we haven't entered t
165 0 => rest.push(tt),
166 1 => {
167 // Here depending on t
168 match tt.clone() {
169 TokenTree::Ident(i
170 let Some(name)
171 // Parsing
172 break;
173 };
174 impl_generics.
175 impl_generics.
176 ty_generics.pu
177 decl_generics.
178 at_start = fal
179 }
180 TokenTree::Ident(_
181 impl_generics.
182 ty_generics.pu
183 at_start = fal
184 }
185 TokenTree::Punct(p
186 impl_generics.
187 ty_generics.pu
188 at_start = tru
189 }
190 // Lifetimes begin
191 TokenTree::Punct(p
192 impl_generics.
193 ty_generics.pu
194 }
195 // Generics can ha
196 TokenTree::Punct(p
197 skip_until_com
198 }
199 _ => impl_generics
200 }
201 }
202 _ => impl_generics.push(tt
203 }
204 }
205 _ => {}
206 }
207 }
208 rest.extend(toks);
209 (
210 Generics {
211 impl_generics,
212 decl_generics,
213 ty_generics,
214 },
215 rest,
216 )
217 }
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