xref: /linux/rust/macros/helpers.rs (revision ec7714e4947909190ffb3041a03311a975350fe0) 
1 // SPDX-License-Identifier: GPL-2.0
2 
3 use proc_macro::{token_stream, Group, Ident, TokenStream, TokenTree};
4 
try_ident(it: &mut token_stream::IntoIter) -> Option<String>5 pub(crate) fn try_ident(it: &mut token_stream::IntoIter) -> Option<String> {
6     if let Some(TokenTree::Ident(ident)) = it.next() {
7         Some(ident.to_string())
8     } else {
9         None
10     }
11 }
12 
try_literal(it: &mut token_stream::IntoIter) -> Option<String>13 pub(crate) fn try_literal(it: &mut token_stream::IntoIter) -> Option<String> {
14     if let Some(TokenTree::Literal(literal)) = it.next() {
15         Some(literal.to_string())
16     } else {
17         None
18     }
19 }
20 
try_string(it: &mut token_stream::IntoIter) -> Option<String>21 pub(crate) fn try_string(it: &mut token_stream::IntoIter) -> Option<String> {
22     try_literal(it).and_then(|string| {
23         if string.starts_with('\"') && string.ends_with('\"') {
24             let content = &string[1..string.len() - 1];
25             if content.contains('\\') {
26                 panic!("Escape sequences in string literals not yet handled");
27             }
28             Some(content.to_string())
29         } else if string.starts_with("r\"") {
30             panic!("Raw string literals are not yet handled");
31         } else {
32             None
33         }
34     })
35 }
36 
expect_ident(it: &mut token_stream::IntoIter) -> String37 pub(crate) fn expect_ident(it: &mut token_stream::IntoIter) -> String {
38     try_ident(it).expect("Expected Ident")
39 }
40 
expect_punct(it: &mut token_stream::IntoIter) -> char41 pub(crate) fn expect_punct(it: &mut token_stream::IntoIter) -> char {
42     if let TokenTree::Punct(punct) = it.next().expect("Reached end of token stream for Punct") {
43         punct.as_char()
44     } else {
45         panic!("Expected Punct");
46     }
47 }
48 
expect_string(it: &mut token_stream::IntoIter) -> String49 pub(crate) fn expect_string(it: &mut token_stream::IntoIter) -> String {
50     try_string(it).expect("Expected string")
51 }
52 
expect_string_ascii(it: &mut token_stream::IntoIter) -> String53 pub(crate) fn expect_string_ascii(it: &mut token_stream::IntoIter) -> String {
54     let string = try_string(it).expect("Expected string");
55     assert!(string.is_ascii(), "Expected ASCII string");
56     string
57 }
58 
expect_group(it: &mut token_stream::IntoIter) -> Group59 pub(crate) fn expect_group(it: &mut token_stream::IntoIter) -> Group {
60     if let TokenTree::Group(group) = it.next().expect("Reached end of token stream for Group") {
61         group
62     } else {
63         panic!("Expected Group");
64     }
65 }
66 
expect_end(it: &mut token_stream::IntoIter)67 pub(crate) fn expect_end(it: &mut token_stream::IntoIter) {
68     if it.next().is_some() {
69         panic!("Expected end");
70     }
71 }
72 
73 /// Given a function declaration, finds the name of the function.
function_name(input: TokenStream) -> Option<Ident>74 pub(crate) fn function_name(input: TokenStream) -> Option<Ident> {
75     let mut input = input.into_iter();
76     while let Some(token) = input.next() {
77         match token {
78             TokenTree::Ident(i) if i.to_string() == "fn" => {
79                 if let Some(TokenTree::Ident(i)) = input.next() {
80                     return Some(i);
81                 }
82                 return None;
83             }
84             _ => continue,
85         }
86     }
87     None
88 }
89 
file() -> String90 pub(crate) fn file() -> String {
91     #[cfg(not(CONFIG_RUSTC_HAS_SPAN_FILE))]
92     {
93         proc_macro::Span::call_site()
94             .source_file()
95             .path()
96             .to_string_lossy()
97             .into_owned()
98     }
99 
100     #[cfg(CONFIG_RUSTC_HAS_SPAN_FILE)]
101     #[allow(clippy::incompatible_msrv)]
102     {
103         proc_macro::Span::call_site().file()
104     }
105 }
106