src/librustdoc/passes/unindent_comments.rs

   1 use std::cmp;
   2 use std::string::String;
   3 use std::usize;
   4
   5 use crate::clean::{self, DocFragment, Item};
   6 use crate::core::DocContext;
   7 use crate::fold::{self, DocFolder};
   8 use crate::passes::Pass;
   9
  10 #[cfg(test)]
  11 mod tests;
  12
  13 pub const UNINDENT_COMMENTS: Pass = Pass {
  14     name: "unindent-comments",
  15     run: unindent_comments,
  16     description: "removes excess indentation on comments in order for markdown to like it",
  17 };
  18
  19 pub fn unindent_comments(krate: clean::Crate, _: &DocContext<'_>) -> clean::Crate {
  20     CommentCleaner.fold_crate(krate)
  21 }
  22
  23 struct CommentCleaner;
  24
  25 impl fold::DocFolder for CommentCleaner {
  26     fn fold_item(&mut self, mut i: Item) -> Option<Item> {
  27         i.attrs.unindent_doc_comments();
  28         self.fold_item_recur(i)
  29     }
  30 }
  31
  32 impl clean::Attributes {
  33     pub fn unindent_doc_comments(&mut self) {
  34         unindent_fragments(&mut self.doc_strings);
  35     }
  36 }
  37
  38 fn unindent_fragments(docs: &mut Vec<DocFragment>) {
  39     for fragment in docs {
  40         match *fragment {
  41             DocFragment::SugaredDoc(_, _, ref mut doc_string)
  42             | DocFragment::RawDoc(_, _, ref mut doc_string)
  43             | DocFragment::Include(_, _, _, ref mut doc_string) => {
  44                 *doc_string = unindent(doc_string)
  45             }
  46         }
  47     }
  48 }
  49
  50 fn unindent(s: &str) -> String {
  51     let lines = s.lines().collect::<Vec<&str>>();
  52     let mut saw_first_line = false;
  53     let mut saw_second_line = false;
  54     let min_indent = lines.iter().fold(usize::MAX, |min_indent, line| {
  55         // After we see the first non-whitespace line, look at
  56         // the line we have. If it is not whitespace, and therefore
  57         // part of the first paragraph, then ignore the indentation
  58         // level of the first line
  59         let ignore_previous_indents =
  60             saw_first_line && !saw_second_line && !line.chars().all(|c| c.is_whitespace());
  61
  62         let min_indent = if ignore_previous_indents { usize::MAX } else { min_indent };
  63
  64         if saw_first_line {
  65             saw_second_line = true;
  66         }
  67
  68         if line.chars().all(|c| c.is_whitespace()) {
  69             min_indent
  70         } else {
  71             saw_first_line = true;
  72             let mut whitespace = 0;
  73             line.chars().all(|char| {
  74                 // Compare against either space or tab, ignoring whether they
  75                 // are mixed or not
  76                 if char == ' ' || char == '\t' {
  77                     whitespace += 1;
  78                     true
  79                 } else {
  80                     false
  81                 }
  82             });
  83             cmp::min(min_indent, whitespace)
  84         }
  85     });
  86
  87     if !lines.is_empty() {
  88         let mut unindented = vec![lines[0].trim_start().to_string()];
  89         unindented.extend_from_slice(
  90             &lines[1..]
  91                 .iter()
  92                 .map(|&line| {
  93                     if line.chars().all(|c| c.is_whitespace()) {
  94                         line.to_string()
  95                     } else {
  96                         assert!(line.len() >= min_indent);
  97                         line[min_indent..].to_string()
  98                     }
  99                 })
 100                 .collect::<Vec<_>>(),
 101         );
 102         unindented.join("\n")
 103     } else {
 104         s.to_string()
 105     }
 106 }