| //! Utilities for manipulating C/C++ comments. |
| |
| use std::iter; |
| |
| /// The type of a comment. |
| #[derive(Debug, PartialEq, Eq)] |
| enum Kind { |
| /// A `///` comment, or something of the like. |
| /// All lines in a comment should start with the same symbol. |
| SingleLines, |
| /// A `/**` comment, where each other line can start with `*` and the |
| /// entire block ends with `*/`. |
| MultiLine, |
| } |
| |
| /// Preprocesses a C/C++ comment so that it is a valid Rust comment. |
| pub fn preprocess(comment: &str, indent: usize) -> String { |
| match self::kind(&comment) { |
| Some(Kind::SingleLines) => preprocess_single_lines(comment, indent), |
| Some(Kind::MultiLine) => preprocess_multi_line(comment, indent), |
| None => comment.to_owned(), |
| } |
| } |
| |
| /// Gets the kind of the doc comment, if it is one. |
| fn kind(comment: &str) -> Option<Kind> { |
| if comment.starts_with("/*") { |
| Some(Kind::MultiLine) |
| } else if comment.starts_with("//") { |
| Some(Kind::SingleLines) |
| } else { |
| None |
| } |
| } |
| |
| fn make_indent(indent: usize) -> String { |
| const RUST_INDENTATION: usize = 4; |
| iter::repeat(' ').take(indent * RUST_INDENTATION).collect() |
| } |
| |
| /// Preprocesses multiple single line comments. |
| /// |
| /// Handles lines starting with both `//` and `///`. |
| fn preprocess_single_lines(comment: &str, indent: usize) -> String { |
| debug_assert!(comment.starts_with("//"), "comment is not single line"); |
| |
| let indent = make_indent(indent); |
| let mut is_first = true; |
| let lines: Vec<_> = comment |
| .lines() |
| .map(|l| l.trim().trim_start_matches('/')) |
| .map(|l| { |
| let indent = if is_first { "" } else { &*indent }; |
| is_first = false; |
| format!("{}///{}", indent, l) |
| }) |
| .collect(); |
| lines.join("\n") |
| } |
| |
| fn preprocess_multi_line(comment: &str, indent: usize) -> String { |
| let comment = comment |
| .trim_start_matches('/') |
| .trim_end_matches('/') |
| .trim_end_matches('*'); |
| |
| let indent = make_indent(indent); |
| // Strip any potential `*` characters preceding each line. |
| let mut is_first = true; |
| let mut lines: Vec<_> = comment |
| .lines() |
| .map(|line| line.trim().trim_start_matches('*').trim_start_matches('!')) |
| .skip_while(|line| line.trim().is_empty()) // Skip the first empty lines. |
| .map(|line| { |
| let indent = if is_first { "" } else { &*indent }; |
| is_first = false; |
| format!("{}///{}", indent, line) |
| }) |
| .collect(); |
| |
| // Remove the trailing line corresponding to the `*/`. |
| if lines |
| .last() |
| .map_or(false, |l| l.trim().is_empty() || l.trim() == "///") |
| { |
| lines.pop(); |
| } |
| |
| lines.join("\n") |
| } |
| |
| #[cfg(test)] |
| mod test { |
| use super::*; |
| |
| #[test] |
| fn picks_up_single_and_multi_line_doc_comments() { |
| assert_eq!(kind("/// hello"), Some(Kind::SingleLines)); |
| assert_eq!(kind("/** world */"), Some(Kind::MultiLine)); |
| } |
| |
| #[test] |
| fn processes_single_lines_correctly() { |
| assert_eq!(preprocess("/// hello", 0), "/// hello"); |
| assert_eq!(preprocess("// hello", 0), "/// hello"); |
| assert_eq!(preprocess("// hello", 0), "/// hello"); |
| } |
| |
| #[test] |
| fn processes_multi_lines_correctly() { |
| assert_eq!( |
| preprocess("/** hello \n * world \n * foo \n */", 0), |
| "/// hello\n/// world\n/// foo" |
| ); |
| |
| assert_eq!( |
| preprocess("/**\nhello\n*world\n*foo\n*/", 0), |
| "///hello\n///world\n///foo" |
| ); |
| } |
| } |