You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
helix/helix-term/src/ui/markdown.rs

262 lines
14 KiB
Rust

use crate::compositor::{Component, Context};
use tui::{
buffer::Buffer as Surface,
text::{Span, Spans, Text},
};
use std::sync::Arc;
use pulldown_cmark::{CodeBlockKind, Event, HeadingLevel, Options, Parser, Tag};
use helix_core::{
syntax::{self, HighlightEvent, Syntax},
Rope,
};
use helix_view::{
graphics::{Margin, Rect, Style},
Theme,
};
pub struct Markdown {
contents: String,
config_loader: Arc<syntax::Loader>,
}
// TODO: pre-render and self reference via Pin
// better yet, just use Tendril + subtendril for references
impl Markdown {
// theme keys, including fallbacks
const TEXT_STYLE: [&'static str; 2] = ["ui.text", "ui"];
const BLOCK_STYLE: [&'static str; 3] = ["markup.raw.inline", "markup.raw", "markup"];
const HEADING_STYLES: [[&'static str; 3]; 6] = [
["markup.heading.1", "markup.heading", "markup"],
["markup.heading.2", "markup.heading", "markup"],
["markup.heading.3", "markup.heading", "markup"],
["markup.heading.4", "markup.heading", "markup"],
["markup.heading.5", "markup.heading", "markup"],
["markup.heading.6", "markup.heading", "markup"],
];
pub fn new(contents: String, config_loader: Arc<syntax::Loader>) -> Self {
Self {
contents,
config_loader,
}
}
fn parse(&self, theme: Option<&Theme>) -> tui::text::Text<'_> {
// // also 2021-03-04T16:33:58.553 helix_lsp::transport [INFO] <- {"contents":{"kind":"markdown","value":"\n```rust\ncore::num\n```\n\n```rust\npub const fn saturating_sub(self, rhs:Self) ->Self\n```\n\n---\n\n```rust\n```"},"range":{"end":{"character":61,"line":101},"start":{"character":47,"line":101}}}
// let text = "\n```rust\ncore::iter::traits::iterator::Iterator\n```\n\n```rust\nfn collect<B: FromIterator<Self::Item>>(self) -> B\nwhere\n Self: Sized,\n```\n\n---\n\nTransforms an iterator into a collection.\n\n`collect()` can take anything iterable, and turn it into a relevant\ncollection. This is one of the more powerful methods in the standard\nlibrary, used in a variety of contexts.\n\nThe most basic pattern in which `collect()` is used is to turn one\ncollection into another. You take a collection, call [`iter`](https://doc.rust-lang.org/nightly/core/iter/traits/iterator/trait.Iterator.html) on it,\ndo a bunch of transformations, and then `collect()` at the end.\n\n`collect()` can also create instances of types that are not typical\ncollections. For example, a [`String`](https://doc.rust-lang.org/nightly/core/iter/std/string/struct.String.html) can be built from [`char`](type@char)s,\nand an iterator of [`Result<T, E>`](https://doc.rust-lang.org/nightly/core/result/enum.Result.html) items can be collected\ninto `Result<Collection<T>, E>`. See the examples below for more.\n\nBecause `collect()` is so general, it can cause problems with type\ninference. As such, `collect()` is one of the few times you'll see\nthe syntax affectionately known as the 'turbofish': `::<>`. This\nhelps the inference algorithm understand specifically which collection\nyou're trying to collect into.\n\n# Examples\n\nBasic usage:\n\n```rust\nlet a = [1, 2, 3];\n\nlet doubled: Vec<i32> = a.iter()\n .map(|&x| x * 2)\n .collect();\n\nassert_eq!(vec![2, 4, 6], doubled);\n```\n\nNote that we needed the `: Vec<i32>` on the left-hand side. This is because\nwe could collect into, for example, a [`VecDeque<T>`](https://doc.rust-lang.org/nightly/core/iter/std/collections/struct.VecDeque.html) instead:\n\n```rust\nuse std::collections::VecDeque;\n\nlet a = [1, 2, 3];\n\nlet doubled: VecDeque<i32> = a.iter().map(|&x| x * 2).collect();\n\nassert_eq!(2, doubled[0]);\nassert_eq!(4, doubled[1]);\nassert_eq!(6, doubled[2]);\n```\n\nUsing the 'turbofish' instead of annotating `doubled`:\n\n```rust\nlet a = [1, 2, 3];\n\nlet doubled = a.iter().map(|x| x * 2).collect::<Vec<i32>>();\n\nassert_eq!(vec![2, 4, 6], doubled);\n```\n\nBecause `collect()` only cares about what you're collecting into, you can\nstill use a partial type hint, `_`, with the turbofish:\n\n```rust\nlet a = [1, 2, 3];\n\nlet doubled = a.iter().map(|x| x * 2).collect::<Vec<_>>();\n\nassert_eq!(vec![2, 4, 6], doubled);\n```\n\nUsing `collect()` to make a [`String`](https://doc.rust-lang.org/nightly/core/iter/std/string/struct.String.html):\n\n```rust\nlet chars = ['g', 'd', 'k', 'k', 'n'];\n\nlet hello: String = chars.iter()\n .map(|&x| x as u8)\n .map(|x| (x + 1) as char)\n .collect();\n\nassert_eq!(\"hello\", hello);\n```\n\nIf you have a list of [`Result<T, E>`](https://doc.rust-lang.org/nightly/core/result/enum.Result.html)s, you can use `collect()` to\nsee if any of them failed:\n\n```rust\nlet results = [Ok(1), Err(\"nope\"), Ok(3), Err(\"bad\")];\n\nlet result: Result<Vec<_>, &str> = results.iter().cloned().collect();\n\n// gives us the first error\nassert_eq!(Err(\"nope\"), result);\n\nlet results = [Ok(1), Ok(3)];\n\nlet result: Result<Vec<_>, &str> = results.iter().cloned().collect();\n\n// gives us the list of answers\nassert_eq!(Ok(vec![1, 3]), result);\n```";
let mut options = Options::empty();
options.insert(Options::ENABLE_STRIKETHROUGH);
let parser = Parser::new_ext(&self.contents, options);
// TODO: if possible, render links as terminal hyperlinks: https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda
let mut tags = Vec::new();
let mut spans = Vec::new();
let mut lines = Vec::new();
let get_theme = |keys: &[&str]| match theme {
Some(theme) => keys
.iter()
.find_map(|key| theme.try_get(key))
.unwrap_or_default(),
None => Default::default(),
};
let text_style = get_theme(&Self::TEXT_STYLE);
let code_style = get_theme(&Self::BLOCK_STYLE);
let heading_styles: Vec<Style> = Self::HEADING_STYLES
.iter()
.map(|key| get_theme(key))
.collect();
let mut list_stack = Vec::new();
for event in parser {
match event {
Event::Start(Tag::List(list)) => list_stack.push(list),
Event::End(Tag::List(_)) => {
list_stack.pop();
}
Event::Start(Tag::Item) => {
tags.push(Tag::Item);
spans.push(Span::from("- "));
}
Event::Start(tag) => {
tags.push(tag);
}
Event::End(tag) => {
tags.pop();
match tag {
Tag::Heading(_, _, _)
| Tag::Paragraph
| Tag::CodeBlock(CodeBlockKind::Fenced(_))
| Tag::Item => {
// whenever code block or paragraph closes, new line
let spans = std::mem::take(&mut spans);
if !spans.is_empty() {
lines.push(Spans::from(spans));
}
lines.push(Spans::default());
}
_ => (),
}
}
Event::Text(text) => {
// TODO: temp workaround
if let Some(Tag::CodeBlock(CodeBlockKind::Fenced(language))) = tags.last() {
if let Some(theme) = theme {
let rope = Rope::from(text.as_ref());
let syntax = self
.config_loader
.language_configuration_for_injection_string(language)
.and_then(|config| config.highlight_config(theme.scopes()))
.map(|config| {
Syntax::new(&rope, config, self.config_loader.clone())
});
if let Some(syntax) = syntax {
// if we have a syntax available, highlight_iter and generate spans
let mut highlights = Vec::new();
for event in syntax.highlight_iter(rope.slice(..), None, None) {
match event.unwrap() {
HighlightEvent::HighlightStart(span) => {
highlights.push(span);
}
HighlightEvent::HighlightEnd => {
highlights.pop();
}
HighlightEvent::Source { start, end } => {
let style = match highlights.first() {
Some(span) => theme.get(&theme.scopes()[span.0]),
None => text_style,
};
let mut slice = &text[start..end];
// TODO: do we need to handle all unicode line endings
// here, or is just '\n' okay?
while let Some(end) = slice.find('\n') {
// emit span up to newline
let text = &slice[..end];
let text = text.replace('\t', " "); // replace tabs
let span = Span::styled(text, style);
spans.push(span);
// truncate slice to after newline
slice = &slice[end + 1..];
// make a new line
let spans = std::mem::take(&mut spans);
lines.push(Spans::from(spans));
}
// if there's anything left, emit it too
if !slice.is_empty() {
let span = Span::styled(
slice.replace('\t', " "),
style,
);
spans.push(span);
}
}
}
}
} else {
for line in text.lines() {
let span = Span::styled(line.to_string(), code_style);
lines.push(Spans::from(span));
}
}
} else {
for line in text.lines() {
let span = Span::styled(line.to_string(), code_style);
lines.push(Spans::from(span));
}
}
} else {
let style = if let Some(Tag::Heading(level, ..)) = tags.last() {
match level {
HeadingLevel::H1 => heading_styles[0],
HeadingLevel::H2 => heading_styles[1],
HeadingLevel::H3 => heading_styles[2],
HeadingLevel::H4 => heading_styles[3],
HeadingLevel::H5 => heading_styles[4],
HeadingLevel::H6 => heading_styles[5],
}
} else {
text_style
};
spans.push(Span::styled(text, style));
}
}
Event::Code(text) | Event::Html(text) => {
spans.push(Span::styled(text, code_style));
}
Event::SoftBreak | Event::HardBreak => {
// let spans = std::mem::replace(&mut spans, Vec::new());
// lines.push(Spans::from(spans));
spans.push(Span::raw(" "));
}
Event::Rule => {
lines.push(Spans::from(Span::styled("---", code_style)));
lines.push(Spans::default());
}
// TaskListMarker(bool) true if checked
_ => {
log::warn!("unhandled markdown event {:?}", event);
}
}
// build up a vec of Paragraph tui widgets
}
if !spans.is_empty() {
lines.push(Spans::from(spans));
}
// if last line is empty, remove it
if let Some(line) = lines.last() {
if line.0.is_empty() {
lines.pop();
}
}
Text::from(lines)
}
}
impl Component for Markdown {
fn render(&mut self, area: Rect, surface: &mut Surface, cx: &mut Context) {
use tui::widgets::{Paragraph, Widget, Wrap};
let text = self.parse(Some(&cx.editor.theme));
let par = Paragraph::new(text)
.wrap(Wrap { trim: false })
.scroll((cx.scroll.unwrap_or_default() as u16, 0));
let margin = Margin {
vertical: 1,
horizontal: 1,
};
par.render(area.inner(&margin), surface);
}
fn required_size(&mut self, viewport: (u16, u16)) -> Option<(u16, u16)> {
let padding = 2;
if padding >= viewport.1 || padding >= viewport.0 {
return None;
}
let contents = self.parse(None);
3 years ago
// TODO: account for tab width
let max_text_width = (viewport.0 - padding).min(120);
let (width, height) = crate::ui::text::required_size(&contents, max_text_width);
Some((width + padding, height + padding))
}
}