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