crates/rust-analyzer/src/markdown.rs

   1 //! Transforms markdown
   2
   3 const RUSTDOC_FENCE: &str = "```";
   4 const RUSTDOC_CODE_BLOCK_ATTRIBUTES_RUST_SPECIFIC: &[&str] = &[
   5     "",
   6     "rust",
   7     "should_panic",
   8     "ignore",
   9     "no_run",
  10     "compile_fail",
  11     "edition2015",
  12     "edition2018",
  13     "edition2021",
  14 ];
  15
  16 pub(crate) fn format_docs(src: &str) -> String {
  17     let mut processed_lines = Vec::new();
  18     let mut in_code_block = false;
  19     let mut is_rust = false;
  20
  21     for mut line in src.lines() {
  22         if in_code_block && is_rust && code_line_ignored_by_rustdoc(line) {
  23             continue;
  24         }
  25
  26         if let Some(header) = line.strip_prefix(RUSTDOC_FENCE) {
  27             in_code_block ^= true;
  28
  29             if in_code_block {
  30                 is_rust = header
  31                     .split(',')
  32                     .all(|sub| RUSTDOC_CODE_BLOCK_ATTRIBUTES_RUST_SPECIFIC.contains(&sub.trim()));
  33
  34                 if is_rust {
  35                     line = "```rust";
  36                 }
  37             }
  38         }
  39
  40         processed_lines.push(line);
  41     }
  42     processed_lines.join("\n")
  43 }
  44
  45 fn code_line_ignored_by_rustdoc(line: &str) -> bool {
  46     let trimmed = line.trim();
  47     trimmed == "#" || trimmed.starts_with("# ") || trimmed.starts_with("#\t")
  48 }
  49
  50 #[cfg(test)]
  51 mod tests {
  52     use super::*;
  53
  54     #[test]
  55     fn test_format_docs_adds_rust() {
  56         let comment = "```\nfn some_rust() {}\n```";
  57         assert_eq!(format_docs(comment), "```rust\nfn some_rust() {}\n```");
  58     }
  59
  60     #[test]
  61     fn test_format_docs_handles_plain_text() {
  62         let comment = "```text\nthis is plain text\n```";
  63         assert_eq!(format_docs(comment), "```text\nthis is plain text\n```");
  64     }
  65
  66     #[test]
  67     fn test_format_docs_handles_non_rust() {
  68         let comment = "```sh\nsupposedly shell code\n```";
  69         assert_eq!(format_docs(comment), "```sh\nsupposedly shell code\n```");
  70     }
  71
  72     #[test]
  73     fn test_format_docs_handles_rust_alias() {
  74         let comment = "```ignore\nlet z = 55;\n```";
  75         assert_eq!(format_docs(comment), "```rust\nlet z = 55;\n```");
  76     }
  77
  78     #[test]
  79     fn test_format_docs_handles_complex_code_block_attrs() {
  80         let comment = "```rust,no_run\nlet z = 55;\n```";
  81         assert_eq!(format_docs(comment), "```rust\nlet z = 55;\n```");
  82     }
  83
  84     #[test]
  85     fn test_format_docs_skips_comments_in_rust_block() {
  86         let comment =
  87             "```rust\n # skip1\n# skip2\n#stay1\nstay2\n#\n #\n   #    \n #\tskip3\n\t#\t\n```";
  88         assert_eq!(format_docs(comment), "```rust\n#stay1\nstay2\n```");
  89     }
  90
  91     #[test]
  92     fn test_format_docs_does_not_skip_lines_if_plain_text() {
  93         let comment =
  94             "```text\n # stay1\n# stay2\n#stay3\nstay4\n#\n #\n   #    \n #\tstay5\n\t#\t\n```";
  95         assert_eq!(
  96             format_docs(comment),
  97             "```text\n # stay1\n# stay2\n#stay3\nstay4\n#\n #\n   #    \n #\tstay5\n\t#\t\n```",
  98         );
  99     }
 100
 101     #[test]
 102     fn test_format_docs_keeps_comments_outside_of_rust_block() {
 103         let comment = " # stay1\n# stay2\n#stay3\nstay4\n#\n #\n   #    \n #\tstay5\n\t#\t";
 104         assert_eq!(format_docs(comment), comment);
 105     }
 106
 107     #[test]
 108     fn test_format_docs_preserves_newlines() {
 109         let comment = "this\nis\nmultiline";
 110         assert_eq!(format_docs(comment), comment);
 111     }
 112
 113     #[test]
 114     fn test_code_blocks_in_comments_marked_as_rust() {
 115         let comment = r#"```rust
 116 fn main(){}
 117 ```
 118 Some comment.
 119 ```
 120 let a = 1;
 121 ```"#;
 122
 123         assert_eq!(
 124             format_docs(comment),
 125             "```rust\nfn main(){}\n```\nSome comment.\n```rust\nlet a = 1;\n```"
 126         );
 127     }
 128
 129     #[test]
 130     fn test_code_blocks_in_comments_marked_as_text() {
 131         let comment = r#"```text
 132 filler
 133 text
 134 ```
 135 Some comment.
 136 ```
 137 let a = 1;
 138 ```"#;
 139
 140         assert_eq!(
 141             format_docs(comment),
 142             "```text\nfiller\ntext\n```\nSome comment.\n```rust\nlet a = 1;\n```"
 143         );
 144     }
 145 }