typst/docs/src/html.rs

494 lines
15 KiB
Rust

use std::fmt::{self, Debug, Formatter};
use std::ops::Range;
use ecow::EcoString;
use heck::{ToKebabCase, ToTitleCase};
use pulldown_cmark as md;
use serde::{Deserialize, Serialize};
use typed_arena::Arena;
use typst::diag::{FileResult, StrResult};
use typst::eval::Tracer;
use typst::foundations::{Bytes, Datetime};
use typst::layout::{Abs, Point, Size};
use typst::syntax::{FileId, Source, VirtualPath};
use typst::text::{Font, FontBook};
use typst::utils::LazyHash;
use typst::{Library, World};
use unscanny::Scanner;
use yaml_front_matter::YamlFrontMatter;
use crate::{contributors, OutlineItem, Resolver, FONTS, LIBRARY};
/// HTML documentation.
#[derive(Serialize)]
#[serde(transparent)]
pub struct Html {
raw: String,
#[serde(skip)]
md: String,
#[serde(skip)]
description: Option<EcoString>,
#[serde(skip)]
outline: Vec<OutlineItem>,
}
impl Html {
/// Create HTML from a raw string.
pub fn new(raw: String) -> Self {
Self {
md: String::new(),
raw,
description: None,
outline: vec![],
}
}
/// Convert markdown to HTML.
#[track_caller]
pub fn markdown(resolver: &dyn Resolver, md: &str, nesting: Option<usize>) -> Self {
let mut text = md;
let mut description = None;
let document = YamlFrontMatter::parse::<Metadata>(md);
if let Ok(document) = &document {
text = &document.content;
description = Some(document.metadata.description.clone())
}
let options = md::Options::ENABLE_TABLES
| md::Options::ENABLE_FOOTNOTES
| md::Options::ENABLE_STRIKETHROUGH
| md::Options::ENABLE_HEADING_ATTRIBUTES;
// Convert `[foo]` to `[foo]($foo)`.
let mut link = |broken: md::BrokenLink| {
assert_eq!(
broken.link_type,
md::LinkType::Shortcut,
"unsupported link type: {:?}",
broken.link_type,
);
Some((
format!("${}", broken.reference.trim_matches('`')).into(),
broken.reference.into_string().into(),
))
};
let ids = Arena::new();
let mut handler = Handler::new(text, resolver, nesting, &ids);
let mut events =
md::Parser::new_with_broken_link_callback(text, options, Some(&mut link))
.peekable();
let iter = std::iter::from_fn(|| loop {
let mut event = events.next()?;
handler.peeked = events.peek().and_then(|event| match event {
md::Event::Text(text) => Some(text.clone()),
_ => None,
});
if handler.handle(&mut event) {
return Some(event);
}
});
let mut raw = String::new();
md::html::push_html(&mut raw, iter);
raw.truncate(raw.trim_end().len());
Html {
md: text.into(),
raw,
description,
outline: handler.outline,
}
}
/// The raw HTML.
pub fn as_str(&self) -> &str {
&self.raw
}
/// The original Markdown, if any.
pub fn md(&self) -> &str {
&self.md
}
/// The title of the HTML.
///
/// Returns `None` if the HTML doesn't start with an `h1` tag.
pub fn title(&self) -> Option<&str> {
let mut s = Scanner::new(&self.raw);
s.eat_if("<h1").then(|| {
s.eat_until('>');
s.eat_if('>');
s.eat_until("</h1>")
})
}
/// The outline of the HTML.
pub fn outline(&self) -> Vec<OutlineItem> {
self.outline.clone()
}
/// The description from the front matter.
pub fn description(&self) -> Option<EcoString> {
self.description.clone()
}
}
impl Debug for Html {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(f, "Html({:?})", self.title().unwrap_or(".."))
}
}
/// Front matter metadata.
#[derive(Deserialize)]
struct Metadata {
description: EcoString,
}
struct Handler<'a> {
text: &'a str,
resolver: &'a dyn Resolver,
peeked: Option<md::CowStr<'a>>,
lang: Option<EcoString>,
code: EcoString,
outline: Vec<OutlineItem>,
nesting: Option<usize>,
ids: &'a Arena<String>,
}
impl<'a> Handler<'a> {
fn new(
text: &'a str,
resolver: &'a dyn Resolver,
nesting: Option<usize>,
ids: &'a Arena<String>,
) -> Self {
Self {
text,
resolver,
peeked: None,
lang: None,
code: EcoString::new(),
outline: vec![],
nesting,
ids,
}
}
fn handle(&mut self, event: &mut md::Event<'a>) -> bool {
match event {
// Rewrite Markdown images.
md::Event::Start(md::Tag::Image(_, path, _)) => {
*path = self.handle_image(path).into();
}
// Rewrite HTML images.
md::Event::Html(html) if html.starts_with("<img") => {
let range = html_attr_range(html, "src").unwrap();
let path = &html[range.clone()];
let mut buf = html.to_string();
buf.replace_range(range, &self.handle_image(path));
*html = buf.into();
}
// Register HTML headings for the outline.
md::Event::Start(md::Tag::Heading(level, id, _)) => {
self.handle_heading(id, level);
}
// Also handle heading closings.
md::Event::End(md::Tag::Heading(level, _, _)) => {
nest_heading(level, self.nesting());
}
// Rewrite contributor sections.
md::Event::Html(html) if html.starts_with("<contributors") => {
let from = html_attr(html, "from").unwrap();
let to = html_attr(html, "to").unwrap();
let Some(output) = contributors(self.resolver, from, to) else {
return false;
};
*html = output.raw.into();
}
// Rewrite links.
md::Event::Start(md::Tag::Link(ty, dest, _)) => {
assert!(
matches!(
ty,
md::LinkType::Inline
| md::LinkType::Reference
| md::LinkType::ShortcutUnknown
| md::LinkType::Autolink
),
"unsupported link type: {ty:?}",
);
*dest = match self.handle_link(dest) {
Ok(link) => link.into(),
Err(err) => panic!("invalid link: {dest} ({err})"),
};
}
// Inline raw.
md::Event::Code(code) => {
let mut chars = code.chars();
let parser = match (chars.next(), chars.next_back()) {
(Some('['), Some(']')) => typst::syntax::parse,
(Some('{'), Some('}')) => typst::syntax::parse_code,
_ => return true,
};
let root = parser(&code[1..code.len() - 1]);
let html = typst::syntax::highlight_html(&root);
*event = md::Event::Html(html.into());
}
// Code blocks.
md::Event::Start(md::Tag::CodeBlock(md::CodeBlockKind::Fenced(lang))) => {
self.lang = Some(lang.as_ref().into());
self.code = EcoString::new();
return false;
}
md::Event::End(md::Tag::CodeBlock(md::CodeBlockKind::Fenced(_))) => {
let Some(lang) = self.lang.take() else { return false };
let html = code_block(self.resolver, &lang, &self.code);
*event = md::Event::Html(html.raw.into());
}
// Example with preview.
md::Event::Text(text) => {
if self.lang.is_some() {
self.code.push_str(text);
return false;
}
}
_ => {}
}
true
}
fn handle_image(&self, link: &str) -> String {
if let Some(data) = typst_dev_assets::get_by_name(link) {
self.resolver.image(link, data)
} else if let Some(url) = self.resolver.link(link) {
url
} else {
panic!("missing image: {link}")
}
}
fn handle_heading(
&mut self,
id_slot: &mut Option<&'a str>,
level: &mut md::HeadingLevel,
) {
nest_heading(level, self.nesting());
if *level == md::HeadingLevel::H1 {
return;
}
let default = self.peeked.as_ref().map(|text| text.to_kebab_case());
let id: &'a str = match (&id_slot, default) {
(Some(id), default) => {
if Some(*id) == default.as_deref() {
eprintln!("heading id #{id} was specified unnecessarily");
}
id
}
(None, Some(default)) => self.ids.alloc(default).as_str(),
(None, None) => panic!("missing heading id {}", self.text),
};
*id_slot = (!id.is_empty()).then_some(id);
// Special case for things like "v0.3.0".
let name = if id.starts_with('v') && id.contains('.') {
id.into()
} else {
id.to_title_case().into()
};
let mut children = &mut self.outline;
let mut depth = *level as usize;
while depth > 2 {
if !children.is_empty() {
children = &mut children.last_mut().unwrap().children;
}
depth -= 1;
}
children.push(OutlineItem { id: id.into(), name, children: vec![] });
}
fn handle_link(&self, link: &str) -> StrResult<String> {
if let Some(link) = self.resolver.link(link) {
return Ok(link);
}
crate::link::resolve(link, self.resolver.base())
}
fn nesting(&self) -> usize {
match self.nesting {
Some(nesting) => nesting,
None => panic!("headings are not allowed here:\n{}", self.text),
}
}
}
/// Render a code block to HTML.
fn code_block(resolver: &dyn Resolver, lang: &str, text: &str) -> Html {
let mut display = String::new();
let mut compile = String::new();
for line in text.lines() {
if let Some(suffix) = line.strip_prefix(">>>") {
compile.push_str(suffix);
compile.push('\n');
} else if let Some(suffix) = line.strip_prefix("<<< ") {
display.push_str(suffix);
display.push('\n');
} else {
display.push_str(line);
display.push('\n');
compile.push_str(line);
compile.push('\n');
}
}
let mut parts = lang.split(':');
let lang = parts.next().unwrap_or(lang);
let mut zoom: Option<[Abs; 4]> = None;
let mut single = false;
if let Some(args) = parts.next() {
single = true;
if !args.contains("single") {
zoom = args
.split(',')
.take(4)
.map(|s| Abs::pt(s.parse().unwrap()))
.collect::<Vec<_>>()
.try_into()
.ok();
}
}
if lang.is_empty() {
let mut buf = String::from("<pre>");
md::escape::escape_html(&mut buf, &display).unwrap();
buf.push_str("</pre>");
return Html::new(buf);
} else if !matches!(lang, "example" | "typ" | "preview") {
let set = &*typst::text::RAW_SYNTAXES;
let buf = syntect::html::highlighted_html_for_string(
&display,
set,
set.find_syntax_by_token(lang)
.unwrap_or_else(|| panic!("unsupported highlighting language: {lang}")),
&typst::text::RAW_THEME,
)
.expect("failed to highlight code");
return Html::new(buf);
}
let mut highlighted = None;
if matches!(lang, "example" | "typ") {
let root = typst::syntax::parse(&display);
let html = Html::new(typst::syntax::highlight_html(&root));
if lang == "typ" {
return Html::new(format!("<pre>{}</pre>", html.as_str()));
}
highlighted = Some(html);
}
let id = FileId::new(None, VirtualPath::new("main.typ"));
let source = Source::new(id, compile);
let world = DocWorld(source);
let mut tracer = Tracer::new();
let mut document = match typst::compile(&world, &mut tracer) {
Ok(doc) => doc,
Err(err) => {
let msg = &err[0].message;
panic!("while trying to compile:\n{text}:\n\nerror: {msg}");
}
};
if let Some([x, y, w, h]) = zoom {
document.pages[0].frame.translate(Point::new(-x, -y));
*document.pages[0].frame.size_mut() = Size::new(w, h);
}
if single {
document.pages.truncate(1);
}
let hash = typst::utils::hash128(text);
resolver.example(hash, highlighted, &document)
}
/// Extract an attribute value from an HTML element.
fn html_attr<'a>(html: &'a str, attr: &str) -> Option<&'a str> {
html.get(html_attr_range(html, attr)?)
}
/// Extract the range of the attribute value of an HTML element.
fn html_attr_range(html: &str, attr: &str) -> Option<Range<usize>> {
let needle = format!("{attr}=\"");
let offset = html.find(&needle)? + needle.len();
let len = html[offset..].find('"')?;
Some(offset..offset + len)
}
/// Increase the nesting level of a Markdown heading.
fn nest_heading(level: &mut md::HeadingLevel, nesting: usize) {
*level = ((*level as usize) + nesting)
.try_into()
.unwrap_or(md::HeadingLevel::H6);
}
/// A world for example compilations.
struct DocWorld(Source);
impl World for DocWorld {
fn library(&self) -> &LazyHash<Library> {
&LIBRARY
}
fn book(&self) -> &LazyHash<FontBook> {
&FONTS.0
}
fn main(&self) -> Source {
self.0.clone()
}
fn source(&self, _: FileId) -> FileResult<Source> {
Ok(self.0.clone())
}
fn file(&self, id: FileId) -> FileResult<Bytes> {
assert!(id.package().is_none());
Ok(Bytes::from_static(
typst_dev_assets::get_by_name(
&id.vpath().as_rootless_path().to_string_lossy(),
)
.unwrap_or_else(|| panic!("failed to load {:?}", id.vpath())),
))
}
fn font(&self, index: usize) -> Option<Font> {
Some(FONTS.1[index].clone())
}
fn today(&self, _: Option<i64>) -> Option<Datetime> {
Some(Datetime::from_ymd(1970, 1, 1).unwrap())
}
}