mdBook/src/utils/mod.rs

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#![allow(missing_docs)] // FIXME: Document this
pub mod fs;
mod string;
pub(crate) mod toml_ext;
use crate::errors::Error;
use regex::Regex;
use pulldown_cmark::{html, CodeBlockKind, CowStr, Event, Options, Parser, Tag};
use std::borrow::Cow;
use std::fmt::Write;
use std::path::Path;
pub use self::string::{
take_anchored_lines, take_lines, take_rustdoc_include_anchored_lines,
take_rustdoc_include_lines,
};
/// Replaces multiple consecutive whitespace characters with a single space character.
pub fn collapse_whitespace(text: &str) -> Cow<'_, str> {
lazy_static! {
static ref RE: Regex = Regex::new(r"\s\s+").unwrap();
}
RE.replace_all(text, " ")
}
/// Convert the given string to a valid HTML element ID.
/// The only restriction is that the ID must not contain any ASCII whitespace.
pub fn normalize_id(content: &str) -> String {
content
.chars()
.filter_map(|ch| {
if ch.is_alphanumeric() || ch == '_' || ch == '-' {
Some(ch.to_ascii_lowercase())
} else if ch.is_whitespace() {
Some('-')
} else {
None
}
})
.collect::<String>()
}
/// Generate an ID for use with anchors which is derived from a "normalised"
/// string.
pub fn id_from_content(content: &str) -> String {
let mut content = content.to_string();
// Skip any tags or html-encoded stuff
const REPL_SUB: &[&str] = &[
"<em>",
"</em>",
"<code>",
"</code>",
"<strong>",
"</strong>",
"&lt;",
"&gt;",
"&amp;",
"&#39;",
"&quot;",
];
for sub in REPL_SUB {
content = content.replace(sub, "");
}
// Remove spaces and hashes indicating a header
let trimmed = content.trim().trim_start_matches('#').trim();
normalize_id(trimmed)
}
/// Fix links to the correct location.
///
/// This adjusts links, such as turning `.md` extensions to `.html`.
///
/// `path` is the path to the page being rendered relative to the root of the
/// book. This is used for the `print.html` page so that links on the print
/// page go to the original location. Normal page rendering sets `path` to
/// None. Ideally, print page links would link to anchors on the print page,
/// but that is very difficult.
fn adjust_links<'a>(event: Event<'a>, path: Option<&Path>) -> Event<'a> {
lazy_static! {
static ref SCHEME_LINK: Regex = Regex::new(r"^[a-z][a-z0-9+.-]*:").unwrap();
static ref MD_LINK: Regex = Regex::new(r"(?P<link>.*)\.md(?P<anchor>#.*)?").unwrap();
}
fn fix<'a>(dest: CowStr<'a>, path: Option<&Path>) -> CowStr<'a> {
if dest.starts_with('#') {
// Fragment-only link.
if let Some(path) = path {
let mut base = path.display().to_string();
if base.ends_with(".md") {
base.replace_range(base.len() - 3.., ".html");
}
return format!("{}{}", base, dest).into();
} else {
return dest;
}
}
// Don't modify links with schemes like `https`.
if !SCHEME_LINK.is_match(&dest) {
// This is a relative link, adjust it as necessary.
let mut fixed_link = String::new();
if let Some(path) = path {
let base = path
.parent()
.expect("path can't be empty")
.to_str()
.expect("utf-8 paths only");
if !base.is_empty() {
write!(fixed_link, "{}/", base).unwrap();
}
}
if let Some(caps) = MD_LINK.captures(&dest) {
fixed_link.push_str(&caps["link"]);
fixed_link.push_str(".html");
if let Some(anchor) = caps.name("anchor") {
fixed_link.push_str(anchor.as_str());
}
} else {
fixed_link.push_str(&dest);
};
return CowStr::from(fixed_link);
}
dest
}
fn fix_html<'a>(html: CowStr<'a>, path: Option<&Path>) -> CowStr<'a> {
// This is a terrible hack, but should be reasonably reliable. Nobody
// should ever parse a tag with a regex. However, there isn't anything
// in Rust that I know of that is suitable for handling partial html
// fragments like those generated by pulldown_cmark.
//
// There are dozens of HTML tags/attributes that contain paths, so
// feel free to add more tags if desired; these are the only ones I
// care about right now.
lazy_static! {
static ref HTML_LINK: Regex =
Regex::new(r#"(<(?:a|img) [^>]*?(?:src|href)=")([^"]+?)""#).unwrap();
}
HTML_LINK
.replace_all(&html, |caps: &regex::Captures<'_>| {
let fixed = fix(caps[2].into(), path);
format!("{}{}\"", &caps[1], fixed)
})
.into_owned()
.into()
}
match event {
Event::Start(Tag::Link(link_type, dest, title)) => {
Event::Start(Tag::Link(link_type, fix(dest, path), title))
}
Event::Start(Tag::Image(link_type, dest, title)) => {
Event::Start(Tag::Image(link_type, fix(dest, path), title))
}
Event::Html(html) => Event::Html(fix_html(html, path)),
_ => event,
}
}
/// Wrapper around the pulldown-cmark parser for rendering markdown to HTML.
pub fn render_markdown(text: &str, curly_quotes: bool) -> String {
render_markdown_with_path(text, curly_quotes, None)
}
pub fn new_cmark_parser(text: &str) -> Parser<'_> {
let mut opts = Options::empty();
opts.insert(Options::ENABLE_TABLES);
opts.insert(Options::ENABLE_FOOTNOTES);
opts.insert(Options::ENABLE_STRIKETHROUGH);
opts.insert(Options::ENABLE_TASKLISTS);
opts.insert(Options::ENABLE_SMART_PUNCTUATION);
Parser::new_ext(text, opts)
}
pub fn render_markdown_with_path(text: &str, curly_quotes: bool, path: Option<&Path>) -> String {
let mut s = String::with_capacity(text.len() * 3 / 2);
let p = new_cmark_parser(text);
let mut converter = EventQuoteConverter::new(curly_quotes);
let events = p
.map(clean_codeblock_headers)
.map(|event| adjust_links(event, path))
.map(|event| converter.convert(event));
html::push_html(&mut s, events);
s
}
struct EventQuoteConverter {
enabled: bool,
convert_text: bool,
}
impl EventQuoteConverter {
fn new(enabled: bool) -> Self {
EventQuoteConverter {
enabled,
convert_text: true,
}
}
fn convert<'a>(&mut self, event: Event<'a>) -> Event<'a> {
if !self.enabled {
return event;
}
match event {
Event::Start(Tag::CodeBlock(_)) => {
self.convert_text = false;
event
}
Event::End(Tag::CodeBlock(_)) => {
self.convert_text = true;
event
}
Event::Text(ref text) if self.convert_text => {
Event::Text(CowStr::from(convert_quotes_to_curly(text)))
}
_ => event,
}
}
}
fn clean_codeblock_headers(event: Event<'_>) -> Event<'_> {
match event {
Event::Start(Tag::CodeBlock(CodeBlockKind::Fenced(ref info))) => {
let info: String = info
.chars()
.map(|x| match x {
' ' | '\t' => ',',
_ => x,
})
.filter(|ch| !ch.is_whitespace())
.collect();
Event::Start(Tag::CodeBlock(CodeBlockKind::Fenced(CowStr::from(info))))
}
_ => event,
}
}
fn convert_quotes_to_curly(original_text: &str) -> String {
// We'll consider the start to be "whitespace".
let mut preceded_by_whitespace = true;
original_text
.chars()
.map(|original_char| {
let converted_char = match original_char {
'\'' => {
if preceded_by_whitespace {
''
} else {
''
}
}
'"' => {
if preceded_by_whitespace {
'“'
} else {
'”'
}
}
_ => original_char,
};
preceded_by_whitespace = original_char.is_whitespace();
converted_char
})
.collect()
}
/// Prints a "backtrace" of some `Error`.
pub fn log_backtrace(e: &Error) {
error!("Error: {}", e);
for cause in e.chain().skip(1) {
error!("\tCaused By: {}", cause);
}
}
#[cfg(test)]
mod tests {
mod render_markdown {
use super::super::render_markdown;
#[test]
fn preserves_external_links() {
assert_eq!(
render_markdown("[example](https://www.rust-lang.org/)", false),
"<p><a href=\"https://www.rust-lang.org/\">example</a></p>\n"
);
}
#[test]
fn it_can_adjust_markdown_links() {
assert_eq!(
render_markdown("[example](example.md)", false),
"<p><a href=\"example.html\">example</a></p>\n"
);
assert_eq!(
render_markdown("[example_anchor](example.md#anchor)", false),
"<p><a href=\"example.html#anchor\">example_anchor</a></p>\n"
);
// this anchor contains 'md' inside of it
assert_eq!(
render_markdown("[phantom data](foo.html#phantomdata)", false),
"<p><a href=\"foo.html#phantomdata\">phantom data</a></p>\n"
);
}
#[test]
fn it_can_keep_quotes_straight() {
assert_eq!(render_markdown("'one'", false), "<p>'one'</p>\n");
}
#[test]
fn it_can_make_quotes_curly_except_when_they_are_in_code() {
let input = r#"
'one'
```
'two'
```
`'three'` 'four'"#;
let expected = r#"<p>one</p>
<pre><code>'two'
</code></pre>
<p><code>'three'</code> four</p>
"#;
assert_eq!(render_markdown(input, true), expected);
}
#[test]
fn whitespace_outside_of_codeblock_header_is_preserved() {
let input = r#"
some text with spaces
```rust
fn main() {
// code inside is unchanged
}
```
more text with spaces
"#;
let expected = r#"<p>some text with spaces</p>
<pre><code class="language-rust">fn main() {
// code inside is unchanged
}
</code></pre>
<p>more text with spaces</p>
"#;
assert_eq!(render_markdown(input, false), expected);
assert_eq!(render_markdown(input, true), expected);
}
#[test]
fn rust_code_block_properties_are_passed_as_space_delimited_class() {
let input = r#"
```rust,no_run,should_panic,property_3
```
"#;
let expected = r#"<pre><code class="language-rust,no_run,should_panic,property_3"></code></pre>
"#;
assert_eq!(render_markdown(input, false), expected);
assert_eq!(render_markdown(input, true), expected);
}
#[test]
fn rust_code_block_properties_with_whitespace_are_passed_as_space_delimited_class() {
let input = r#"
```rust, no_run,,,should_panic , ,property_3
```
"#;
let expected = r#"<pre><code class="language-rust,,,,,no_run,,,should_panic,,,,property_3"></code></pre>
"#;
assert_eq!(render_markdown(input, false), expected);
assert_eq!(render_markdown(input, true), expected);
}
#[test]
fn rust_code_block_without_properties_has_proper_html_class() {
let input = r#"
```rust
```
"#;
let expected = r#"<pre><code class="language-rust"></code></pre>
"#;
assert_eq!(render_markdown(input, false), expected);
assert_eq!(render_markdown(input, true), expected);
let input = r#"
```rust
```
"#;
assert_eq!(render_markdown(input, false), expected);
assert_eq!(render_markdown(input, true), expected);
}
}
mod html_munging {
use super::super::{id_from_content, normalize_id};
#[test]
fn it_generates_anchors() {
assert_eq!(
id_from_content("## Method-call expressions"),
"method-call-expressions"
);
assert_eq!(id_from_content("## **Bold** title"), "bold-title");
assert_eq!(id_from_content("## `Code` title"), "code-title");
}
#[test]
fn it_generates_anchors_from_non_ascii_initial() {
assert_eq!(
id_from_content("## `--passes`: add more rustdoc passes"),
"--passes-add-more-rustdoc-passes"
);
assert_eq!(
id_from_content("## 中文標題 CJK title"),
"中文標題-cjk-title"
);
assert_eq!(id_from_content("## Über"), "Über");
}
#[test]
fn it_normalizes_ids() {
assert_eq!(
normalize_id("`--passes`: add more rustdoc passes"),
"--passes-add-more-rustdoc-passes"
);
assert_eq!(
normalize_id("Method-call 🐙 expressions \u{1f47c}"),
"method-call--expressions-"
);
assert_eq!(normalize_id("_-_12345"), "_-_12345");
assert_eq!(normalize_id("12345"), "12345");
assert_eq!(normalize_id("中文"), "中文");
assert_eq!(normalize_id("にほんご"), "にほんご");
assert_eq!(normalize_id("한국어"), "한국어");
assert_eq!(normalize_id(""), "");
}
}
mod convert_quotes_to_curly {
use super::super::convert_quotes_to_curly;
#[test]
fn it_converts_single_quotes() {
assert_eq!(convert_quotes_to_curly("'one', 'two'"), "one, two");
}
#[test]
fn it_converts_double_quotes() {
assert_eq!(convert_quotes_to_curly(r#""one", "two""#), "“one”, “two”");
}
#[test]
fn it_treats_tab_as_whitespace() {
assert_eq!(convert_quotes_to_curly("\t'one'"), "\tone");
}
}
}