bindgen/ir/
comment.rs

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1//! Utilities for manipulating C/C++ comments.
2
3/// The type of a comment.
4#[derive(Debug, PartialEq, Eq)]
5enum Kind {
6    /// A `///` comment, or something of the like.
7    /// All lines in a comment should start with the same symbol.
8    SingleLines,
9    /// A `/**` comment, where each other line can start with `*` and the
10    /// entire block ends with `*/`.
11    MultiLine,
12}
13
14/// Preprocesses a C/C++ comment so that it is a valid Rust comment.
15pub(crate) fn preprocess(comment: &str) -> String {
16    match kind(comment) {
17        Some(Kind::SingleLines) => preprocess_single_lines(comment),
18        Some(Kind::MultiLine) => preprocess_multi_line(comment),
19        None => comment.to_owned(),
20    }
21}
22
23/// Gets the kind of the doc comment, if it is one.
24fn kind(comment: &str) -> Option<Kind> {
25    if comment.starts_with("/*") {
26        Some(Kind::MultiLine)
27    } else if comment.starts_with("//") {
28        Some(Kind::SingleLines)
29    } else {
30        None
31    }
32}
33
34/// Preprocesses multiple single line comments.
35///
36/// Handles lines starting with both `//` and `///`.
37fn preprocess_single_lines(comment: &str) -> String {
38    debug_assert!(comment.starts_with("//"), "comment is not single line");
39
40    let lines: Vec<_> = comment
41        .lines()
42        .map(|l| l.trim().trim_start_matches('/'))
43        .collect();
44    lines.join("\n")
45}
46
47fn preprocess_multi_line(comment: &str) -> String {
48    let comment = comment
49        .trim_start_matches('/')
50        .trim_end_matches('/')
51        .trim_end_matches('*');
52
53    // Strip any potential `*` characters preceding each line.
54    let mut lines: Vec<_> = comment
55        .lines()
56        .map(|line| line.trim().trim_start_matches('*').trim_start_matches('!'))
57        .skip_while(|line| line.trim().is_empty()) // Skip the first empty lines.
58        .collect();
59
60    // Remove the trailing line corresponding to the `*/`.
61    if lines.last().is_some_and(|l| l.trim().is_empty()) {
62        lines.pop();
63    }
64
65    lines.join("\n")
66}
67
68#[cfg(test)]
69mod test {
70    use super::*;
71
72    #[test]
73    fn picks_up_single_and_multi_line_doc_comments() {
74        assert_eq!(kind("/// hello"), Some(Kind::SingleLines));
75        assert_eq!(kind("/** world */"), Some(Kind::MultiLine));
76    }
77
78    #[test]
79    fn processes_single_lines_correctly() {
80        assert_eq!(preprocess("///"), "");
81        assert_eq!(preprocess("/// hello"), " hello");
82        assert_eq!(preprocess("// hello"), " hello");
83        assert_eq!(preprocess("//    hello"), "    hello");
84    }
85
86    #[test]
87    fn processes_multi_lines_correctly() {
88        assert_eq!(preprocess("/**/"), "");
89
90        assert_eq!(
91            preprocess("/** hello \n * world \n * foo \n */"),
92            " hello\n world\n foo"
93        );
94
95        assert_eq!(
96            preprocess("/**\nhello\n*world\n*foo\n*/"),
97            "hello\nworld\nfoo"
98        );
99    }
100}
bindgen/ir/comment.rs

bindgen/ir/
comment.rs
