zola/components/rendering/src/table_of_contents.rs
2018-09-09 19:43:14 +02:00

191 lines
5.5 KiB
Rust

use tera::{Tera, Context as TeraContext};
use front_matter::InsertAnchor;
#[derive(Debug, PartialEq, Clone, Serialize)]
pub struct Header {
#[serde(skip_serializing)]
pub level: i32,
pub id: String,
pub title: String,
pub permalink: String,
pub children: Vec<Header>,
}
impl Header {
pub fn from_temp_header(tmp: &TempHeader, children: Vec<Header>) -> Header {
Header {
level: tmp.level,
id: tmp.id.clone(),
title: tmp.title.clone(),
permalink: tmp.permalink.clone(),
children,
}
}
}
/// Populated while receiving events from the markdown parser
#[derive(Debug, PartialEq, Clone)]
pub struct TempHeader {
pub level: i32,
pub id: String,
pub permalink: String,
pub title: String,
}
impl TempHeader {
pub fn new(level: i32) -> TempHeader {
TempHeader {
level,
id: String::new(),
permalink: String::new(),
title: String::new(),
}
}
pub fn push(&mut self, val: &str) {
self.title += val;
}
/// Transform all the information we have about this header into the HTML string for it
pub fn to_string(&self, tera: &Tera, insert_anchor: InsertAnchor) -> String {
let anchor_link = if insert_anchor != InsertAnchor::None {
let mut c = TeraContext::new();
c.insert("id", &self.id);
tera.render("anchor-link.html", &c).unwrap()
} else {
String::new()
};
match insert_anchor {
InsertAnchor::None => format!("<h{lvl} id=\"{id}\">{t}</h{lvl}>\n", lvl = self.level, t = self.title, id = self.id),
InsertAnchor::Left => format!("<h{lvl} id=\"{id}\">{a}{t}</h{lvl}>\n", lvl = self.level, a = anchor_link, t = self.title, id = self.id),
InsertAnchor::Right => format!("<h{lvl} id=\"{id}\">{t}{a}</h{lvl}>\n", lvl = self.level, a = anchor_link, t = self.title, id = self.id),
}
}
}
impl Default for TempHeader {
fn default() -> Self {
TempHeader::new(0)
}
}
/// Recursively finds children of a header
fn find_children(parent_level: i32, start_at: usize, temp_headers: &[TempHeader]) -> (usize, Vec<Header>) {
let mut headers = vec![];
let mut start_at = start_at;
// If we have children, we will need to skip some headers since they are already inserted
let mut to_skip = 0;
for h in &temp_headers[start_at..] {
// stop when we encounter a title at the same level or higher
// than the parent one. Here a lower integer is considered higher as we are talking about
// HTML headers: h1, h2, h3, h4, h5 and h6
if h.level <= parent_level {
return (start_at, headers);
}
// Do we need to skip some headers?
if to_skip > 0 {
to_skip -= 1;
continue;
}
let (end, children) = find_children(h.level, start_at + 1, temp_headers);
headers.push(Header::from_temp_header(h, children));
// we didn't find any children
if end == start_at {
start_at += 1;
to_skip = 0;
} else {
// calculates how many we need to skip. Since the find_children start_at starts at 1,
// we need to remove 1 to ensure correctness
to_skip = end - start_at - 1;
start_at = end;
}
// we don't want to index out of bounds
if start_at + 1 > temp_headers.len() {
return (start_at, headers);
}
}
(start_at, headers)
}
/// Converts the flat temp headers into a nested set of headers
/// representing the hierarchy
pub fn make_table_of_contents(temp_headers: &[TempHeader]) -> Vec<Header> {
let mut toc = vec![];
let mut start_idx = 0;
for (i, h) in temp_headers.iter().enumerate() {
if i < start_idx {
continue;
}
let (end_idx, children) = find_children(h.level, start_idx + 1, temp_headers);
start_idx = end_idx;
toc.push(Header::from_temp_header(h, children));
}
toc
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn can_make_basic_toc() {
let input = vec![
TempHeader::new(1),
TempHeader::new(1),
TempHeader::new(1),
];
let toc = make_table_of_contents(&input);
assert_eq!(toc.len(), 3);
}
#[test]
fn can_make_more_complex_toc() {
let input = vec![
TempHeader::new(1),
TempHeader::new(2),
TempHeader::new(2),
TempHeader::new(3),
TempHeader::new(2),
TempHeader::new(1),
TempHeader::new(2),
TempHeader::new(3),
TempHeader::new(3),
];
let toc = make_table_of_contents(&input);
assert_eq!(toc.len(), 2);
assert_eq!(toc[0].children.len(), 3);
assert_eq!(toc[1].children.len(), 1);
assert_eq!(toc[0].children[1].children.len(), 1);
assert_eq!(toc[1].children[0].children.len(), 2);
}
#[test]
fn can_make_messy_toc() {
let input = vec![
TempHeader::new(3),
TempHeader::new(2),
TempHeader::new(2),
TempHeader::new(3),
TempHeader::new(2),
TempHeader::new(1),
TempHeader::new(4),
];
let toc = make_table_of_contents(&input);
assert_eq!(toc.len(), 5);
assert_eq!(toc[2].children.len(), 1);
assert_eq!(toc[4].children.len(), 1);
}
}