rust/src/librustdoc/html/markdown.rs
2014-04-18 17:25:34 -07:00

357 lines
12 KiB
Rust

// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Markdown formatting for rustdoc
//!
//! This module implements markdown formatting through the sundown C-library
//! (bundled into the rust runtime). This module self-contains the C bindings
//! and necessary legwork to render markdown, and exposes all of the
//! functionality through a unit-struct, `Markdown`, which has an implementation
//! of `fmt::Show`. Example usage:
//!
//! ```rust,ignore
//! use rustdoc::html::markdown::Markdown;
//!
//! let s = "My *markdown* _text_";
//! let html = format!("{}", Markdown(s));
//! // ... something using html
//! ```
#![allow(non_camel_case_types)]
use libc;
use std::cast;
use std::fmt;
use std::io;
use std::local_data;
use std::mem;
use std::str;
use std::slice;
use collections::HashMap;
use html::toc::TocBuilder;
use html::highlight;
/// A unit struct which has the `fmt::Show` trait implemented. When
/// formatted, this struct will emit the HTML corresponding to the rendered
/// version of the contained markdown string.
pub struct Markdown<'a>(pub &'a str);
/// A unit struct like `Markdown`, that renders the markdown with a
/// table of contents.
pub struct MarkdownWithToc<'a>(pub &'a str);
static OUTPUT_UNIT: libc::size_t = 64;
static MKDEXT_NO_INTRA_EMPHASIS: libc::c_uint = 1 << 0;
static MKDEXT_TABLES: libc::c_uint = 1 << 1;
static MKDEXT_FENCED_CODE: libc::c_uint = 1 << 2;
static MKDEXT_AUTOLINK: libc::c_uint = 1 << 3;
static MKDEXT_STRIKETHROUGH: libc::c_uint = 1 << 4;
type sd_markdown = libc::c_void; // this is opaque to us
struct sd_callbacks {
blockcode: Option<extern "C" fn(*buf, *buf, *buf, *libc::c_void)>,
blockquote: Option<extern "C" fn(*buf, *buf, *libc::c_void)>,
blockhtml: Option<extern "C" fn(*buf, *buf, *libc::c_void)>,
header: Option<extern "C" fn(*buf, *buf, libc::c_int, *libc::c_void)>,
other: [libc::size_t, ..22],
}
struct html_toc_data {
header_count: libc::c_int,
current_level: libc::c_int,
level_offset: libc::c_int,
}
struct html_renderopt {
toc_data: html_toc_data,
flags: libc::c_uint,
link_attributes: Option<extern "C" fn(*buf, *buf, *libc::c_void)>,
}
struct my_opaque {
opt: html_renderopt,
dfltblk: extern "C" fn(*buf, *buf, *buf, *libc::c_void),
toc_builder: Option<TocBuilder>,
}
struct buf {
data: *u8,
size: libc::size_t,
asize: libc::size_t,
unit: libc::size_t,
}
// sundown FFI
#[link(name = "sundown", kind = "static")]
extern {
fn sdhtml_renderer(callbacks: *sd_callbacks,
options_ptr: *html_renderopt,
render_flags: libc::c_uint);
fn sd_markdown_new(extensions: libc::c_uint,
max_nesting: libc::size_t,
callbacks: *sd_callbacks,
opaque: *libc::c_void) -> *sd_markdown;
fn sd_markdown_render(ob: *buf,
document: *u8,
doc_size: libc::size_t,
md: *sd_markdown);
fn sd_markdown_free(md: *sd_markdown);
fn bufnew(unit: libc::size_t) -> *buf;
fn bufputs(b: *buf, c: *libc::c_char);
fn bufrelease(b: *buf);
}
/// Returns Some(code) if `s` is a line that should be stripped from
/// documentation but used in example code. `code` is the portion of
/// `s` that should be used in tests. (None for lines that should be
/// left as-is.)
fn stripped_filtered_line<'a>(s: &'a str) -> Option<&'a str> {
let trimmed = s.trim();
if trimmed.starts_with("# ") {
Some(trimmed.slice_from(2))
} else {
None
}
}
local_data_key!(used_header_map: HashMap<~str, uint>)
pub fn render(w: &mut io::Writer, s: &str, print_toc: bool) -> fmt::Result {
extern fn block(ob: *buf, text: *buf, lang: *buf, opaque: *libc::c_void) {
unsafe {
let my_opaque: &my_opaque = cast::transmute(opaque);
slice::raw::buf_as_slice((*text).data, (*text).size as uint, |text| {
let text = str::from_utf8(text).unwrap();
let mut lines = text.lines().filter(|l| stripped_filtered_line(*l).is_none());
let text = lines.collect::<Vec<&str>>().connect("\n");
let buf = buf {
data: text.as_bytes().as_ptr(),
size: text.len() as libc::size_t,
asize: text.len() as libc::size_t,
unit: 0,
};
let rendered = if lang.is_null() {
false
} else {
slice::raw::buf_as_slice((*lang).data,
(*lang).size as uint, |rlang| {
let rlang = str::from_utf8(rlang).unwrap();
if rlang.contains("notrust") {
(my_opaque.dfltblk)(ob, &buf, lang, opaque);
true
} else {
false
}
})
};
if !rendered {
let output = highlight::highlight(text, None).to_c_str();
output.with_ref(|r| {
bufputs(ob, r)
})
}
})
}
}
extern fn header(ob: *buf, text: *buf, level: libc::c_int,
opaque: *libc::c_void) {
// sundown does this, we may as well too
"\n".with_c_str(|p| unsafe { bufputs(ob, p) });
// Extract the text provided
let s = if text.is_null() {
"".to_owned()
} else {
unsafe {
str::raw::from_buf_len((*text).data, (*text).size as uint)
}
};
// Transform the contents of the header into a hyphenated string
let id = s.words().map(|s| {
match s.to_ascii_opt() {
Some(s) => s.to_lower().into_str(),
None => s.to_owned()
}
}).collect::<Vec<~str>>().connect("-");
let opaque = unsafe {&mut *(opaque as *mut my_opaque)};
// Make sure our hyphenated ID is unique for this page
let id = local_data::get_mut(used_header_map, |map| {
let map = map.unwrap();
match map.find_mut(&id) {
None => {}
Some(a) => { *a += 1; return format!("{}-{}", id, *a - 1) }
}
map.insert(id.clone(), 1);
id.clone()
});
let sec = match opaque.toc_builder {
Some(ref mut builder) => {
builder.push(level as u32, s.clone(), id.clone())
}
None => {""}
};
// Render the HTML
let text = format!(r#"<h{lvl} id="{id}" class='section-link'><a
href="\#{id}">{sec_len,plural,=0{}other{{sec} }}{}</a></h{lvl}>"#,
s, lvl = level, id = id,
sec_len = sec.len(), sec = sec);
text.with_c_str(|p| unsafe { bufputs(ob, p) });
}
// This code is all lifted from examples/sundown.c in the sundown repo
unsafe {
let ob = bufnew(OUTPUT_UNIT);
let extensions = MKDEXT_NO_INTRA_EMPHASIS | MKDEXT_TABLES |
MKDEXT_FENCED_CODE | MKDEXT_AUTOLINK |
MKDEXT_STRIKETHROUGH;
let options = html_renderopt {
toc_data: html_toc_data {
header_count: 0,
current_level: 0,
level_offset: 0,
},
flags: 0,
link_attributes: None,
};
let mut callbacks: sd_callbacks = mem::init();
sdhtml_renderer(&callbacks, &options, 0);
let mut opaque = my_opaque {
opt: options,
dfltblk: callbacks.blockcode.unwrap(),
toc_builder: if print_toc {Some(TocBuilder::new())} else {None}
};
callbacks.blockcode = Some(block);
callbacks.header = Some(header);
let markdown = sd_markdown_new(extensions, 16, &callbacks,
&mut opaque as *mut my_opaque as *libc::c_void);
sd_markdown_render(ob, s.as_ptr(), s.len() as libc::size_t, markdown);
sd_markdown_free(markdown);
let mut ret = match opaque.toc_builder {
Some(b) => write!(w, "<nav id=\"TOC\">{}</nav>", b.into_toc()),
None => Ok(())
};
if ret.is_ok() {
ret = slice::raw::buf_as_slice((*ob).data, (*ob).size as uint, |buf| {
w.write(buf)
});
}
bufrelease(ob);
ret
}
}
pub fn find_testable_code(doc: &str, tests: &mut ::test::Collector) {
extern fn block(_ob: *buf, text: *buf, lang: *buf, opaque: *libc::c_void) {
unsafe {
if text.is_null() { return }
let (should_fail, no_run, ignore, notrust) = if lang.is_null() {
(false, false, false, false)
} else {
slice::raw::buf_as_slice((*lang).data,
(*lang).size as uint, |lang| {
let s = str::from_utf8(lang).unwrap();
(s.contains("should_fail"),
s.contains("no_run"),
s.contains("ignore"),
s.contains("notrust"))
})
};
if notrust { return }
slice::raw::buf_as_slice((*text).data, (*text).size as uint, |text| {
let tests = &mut *(opaque as *mut ::test::Collector);
let text = str::from_utf8(text).unwrap();
let mut lines = text.lines().map(|l| stripped_filtered_line(l).unwrap_or(l));
let text = lines.collect::<Vec<&str>>().connect("\n");
tests.add_test(text, should_fail, no_run, ignore);
})
}
}
extern fn header(_ob: *buf, text: *buf, level: libc::c_int, opaque: *libc::c_void) {
unsafe {
let tests = &mut *(opaque as *mut ::test::Collector);
if text.is_null() {
tests.register_header("", level as u32);
} else {
slice::raw::buf_as_slice((*text).data, (*text).size as uint, |text| {
let text = str::from_utf8(text).unwrap();
tests.register_header(text, level as u32);
})
}
}
}
unsafe {
let ob = bufnew(OUTPUT_UNIT);
let extensions = MKDEXT_NO_INTRA_EMPHASIS | MKDEXT_TABLES |
MKDEXT_FENCED_CODE | MKDEXT_AUTOLINK |
MKDEXT_STRIKETHROUGH;
let callbacks = sd_callbacks {
blockcode: Some(block),
blockquote: None,
blockhtml: None,
header: Some(header),
other: mem::init()
};
let tests = tests as *mut ::test::Collector as *libc::c_void;
let markdown = sd_markdown_new(extensions, 16, &callbacks, tests);
sd_markdown_render(ob, doc.as_ptr(), doc.len() as libc::size_t,
markdown);
sd_markdown_free(markdown);
bufrelease(ob);
}
}
/// By default this markdown renderer generates anchors for each header in the
/// rendered document. The anchor name is the contents of the header spearated
/// by hyphens, and a task-local map is used to disambiguate among duplicate
/// headers (numbers are appended).
///
/// This method will reset the local table for these headers. This is typically
/// used at the beginning of rendering an entire HTML page to reset from the
/// previous state (if any).
pub fn reset_headers() {
local_data::set(used_header_map, HashMap::new())
}
impl<'a> fmt::Show for Markdown<'a> {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
let Markdown(md) = *self;
// This is actually common enough to special-case
if md.len() == 0 { return Ok(()) }
render(fmt.buf, md.as_slice(), false)
}
}
impl<'a> fmt::Show for MarkdownWithToc<'a> {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
let MarkdownWithToc(md) = *self;
render(fmt.buf, md.as_slice(), true)
}
}