src/rustbook/book.rs

   1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 //! Basic data structures for representing a book.
  12
  13 use std::io::prelude::*;
  14 use std::io::BufReader;
  15 use std::iter;
  16 use std::path::{Path, PathBuf};
  17
  18 pub struct BookItem {
  19     pub title: String,
  20     pub path: PathBuf,
  21     pub path_to_root: PathBuf,
  22     pub children: Vec<BookItem>,
  23 }
  24
  25 pub struct Book {
  26     pub chapters: Vec<BookItem>,
  27 }
  28
  29 /// A depth-first iterator over a book.
  30 pub struct BookItems<'a> {
  31     cur_items: &'a [BookItem],
  32     cur_idx: usize,
  33     stack: Vec<(&'a [BookItem], usize)>,
  34 }
  35
  36 impl<'a> Iterator for BookItems<'a> {
  37     type Item = (String, &'a BookItem);
  38
  39     fn next(&mut self) -> Option<(String, &'a BookItem)> {
  40         loop {
  41             if self.cur_idx >= self.cur_items.len() {
  42                 match self.stack.pop() {
  43                     None => return None,
  44                     Some((parent_items, parent_idx)) => {
  45                         self.cur_items = parent_items;
  46                         self.cur_idx = parent_idx + 1;
  47                     }
  48                 }
  49             } else {
  50                 let cur = self.cur_items.get(self.cur_idx).unwrap();
  51
  52                 let mut section = "".to_string();
  53                 for &(_, idx) in &self.stack {
  54                     section.push_str(&(idx + 1).to_string()[..]);
  55                     section.push('.');
  56                 }
  57                 section.push_str(&(self.cur_idx + 1).to_string()[..]);
  58                 section.push('.');
  59
  60                 self.stack.push((self.cur_items, self.cur_idx));
  61                 self.cur_items = &cur.children[..];
  62                 self.cur_idx = 0;
  63                 return Some((section, cur))
  64             }
  65         }
  66     }
  67 }
  68
  69 impl Book {
  70     pub fn iter(&self) -> BookItems {
  71         BookItems {
  72             cur_items: &self.chapters[..],
  73             cur_idx: 0,
  74             stack: Vec::new(),
  75         }
  76     }
  77 }
  78
  79 /// Construct a book by parsing a summary (markdown table of contents).
  80 pub fn parse_summary(input: &mut Read, src: &Path) -> Result<Book, Vec<String>> {
  81     fn collapse(stack: &mut Vec<BookItem>,
  82                 top_items: &mut Vec<BookItem>,
  83                 to_level: usize) {
  84         loop {
  85             if stack.len() < to_level { return }
  86             if stack.len() == 1 {
  87                 top_items.push(stack.pop().unwrap());
  88                 return;
  89             }
  90
  91             let tip = stack.pop().unwrap();
  92             let last = stack.len() - 1;
  93             stack[last].children.push(tip);
  94         }
  95     }
  96
  97     let mut top_items = vec!();
  98     let mut stack = vec!();
  99     let mut errors = vec!();
 100
 101     // always include the introduction
 102     top_items.push(BookItem {
 103         title: "Introduction".to_string(),
 104         path: PathBuf::from("README.md"),
 105         path_to_root: PathBuf::from(""),
 106         children: vec!(),
 107     });
 108
 109     for line_result in BufReader::new(input).lines() {
 110         let line = match line_result {
 111             Ok(line) => line,
 112             Err(err) => {
 113                 errors.push(err.to_string());
 114                 return Err(errors);
 115             }
 116         };
 117
 118         let star_idx = match line.find("*") { Some(i) => i, None => continue };
 119
 120         let start_bracket = star_idx + line[star_idx..].find("[").unwrap();
 121         let end_bracket = start_bracket + line[start_bracket..].find("](").unwrap();
 122         let start_paren = end_bracket + 1;
 123         let end_paren = start_paren + line[start_paren..].find(")").unwrap();
 124
 125         let given_path = &line[start_paren + 1 .. end_paren];
 126         let title = line[start_bracket + 1..end_bracket].to_string();
 127         let indent = &line[..star_idx];
 128
 129         let path_from_root = match src.join(given_path).strip_prefix(src) {
 130             Ok(p) => p.to_path_buf(),
 131             Err(..) => {
 132                 errors.push(format!("paths in SUMMARY.md must be relative, \
 133                                      but path '{}' for section '{}' is not.",
 134                                      given_path, title));
 135                 PathBuf::new()
 136             }
 137         };
 138         let path_to_root = PathBuf::from(&iter::repeat("../")
 139                                          .take(path_from_root.components().count() - 1)
 140                                          .collect::<String>());
 141         let item = BookItem {
 142             title: title,
 143             path: path_from_root,
 144             path_to_root: path_to_root,
 145             children: vec!(),
 146         };
 147         let level = indent.chars().map(|c| -> usize {
 148             match c {
 149                 ' ' => 1,
 150                 '\t' => 4,
 151                 _ => unreachable!()
 152             }
 153         }).sum::<usize>() / 4 + 1;
 154
 155         if level > stack.len() + 1 {
 156             errors.push(format!("section '{}' is indented too deeply; \
 157                                  found {}, expected {} or less",
 158                                 item.title, level, stack.len() + 1));
 159         } else if level <= stack.len() {
 160             collapse(&mut stack, &mut top_items, level);
 161         }
 162         stack.push(item)
 163     }
 164
 165     if errors.is_empty() {
 166         collapse(&mut stack, &mut top_items, 1);
 167         Ok(Book { chapters: top_items })
 168     } else {
 169         Err(errors)
 170     }
 171 }