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refactor(cheddar): Split out a library with rendering logic

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Splits `main.rs` into `lib.rs` and `bin/cheddar.rs`, which enables
reuse of cheddar's rendering logic in other Rust applications.

Change-Id: Ifd1a44a8d1620c595550a0a497a25b0563e917ca
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3060
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
This commit is contained in:
Vincent Ambo 2021-04-30 22:39:55 +02:00 committed by tazjin
parent 713f066297
commit d311af9bc0
2 changed files with 148 additions and 131 deletions
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135
tools/cheddar/src/bin/cheddar.rs Normal file
View file

@ -0,0 +1,135 @@
//! This file defines the binary for cheddar, which can be interacted
//! with in two different ways:
//!
//! 1. As a CLI tool that acts as a cgit filter.
//! 2. As a long-running HTTP server that handles rendering requests
//! (matching the SourceGraph protocol).
use clap::{App, Arg};
use rouille::Response;
use rouille::{router, try_or_400};
use serde::Deserialize;
use serde_json::json;
use std::collections::HashMap;
use std::io;
use cheddar::{THEMES, format_code, format_markdown};
// Server endpoint for rendering the syntax of source code. This
// replaces the 'syntect_server' component of Sourcegraph.
fn code_endpoint(request: &rouille::Request) -> rouille::Response {
#[derive(Deserialize)]
struct SourcegraphQuery {
filepath: String,
theme: String,
code: String,
}
let query: SourcegraphQuery = try_or_400!(rouille::input::json_input(request));
let mut buf: Vec<u8> = Vec::new();
// We don't use syntect with the sourcegraph themes bundled
// currently, so let's fall back to something that is kind of
// similar (tm).
let theme = &THEMES.themes[match query.theme.as_str() {
"Sourcegraph (light)" => "Solarized (light)",
_ => "Solarized (dark)",
}];
format_code(theme, &mut query.code.as_bytes(), &mut buf, &query.filepath);
Response::json(&json!({
"is_plaintext": false,
"data": String::from_utf8_lossy(&buf)
}))
}
// Server endpoint for rendering a Markdown file.
fn markdown_endpoint(request: &rouille::Request) -> rouille::Response {
let mut texts: HashMap<String, String> = try_or_400!(rouille::input::json_input(request));
for text in texts.values_mut() {
let mut buf: Vec<u8> = Vec::new();
format_markdown(&mut text.as_bytes(), &mut buf);
*text = String::from_utf8_lossy(&buf).to_string();
}
Response::json(&texts)
}
fn highlighting_server(listen: &str) {
println!("Starting syntax highlighting server on '{}'", listen);
rouille::start_server(listen, move |request| {
router!(request,
// Markdown rendering route
(POST) (/markdown) => {
markdown_endpoint(request)
},
// Code rendering route
(POST) (/) => {
code_endpoint(request)
},
_ => {
rouille::Response::empty_404()
},
)
});
}
fn main() {
// Parse the command-line flags passed to cheddar to determine
// whether it is running in about-filter mode (`--about-filter`)
// and what file extension has been supplied.
let matches = App::new("cheddar")
.about("TVL's syntax highlighter")
.arg(
Arg::with_name("about-filter")
.help("Run as a cgit about-filter (renders Markdown)")
.long("about-filter")
.takes_value(false),
)
.arg(
Arg::with_name("sourcegraph-server")
.help("Run as a Sourcegraph compatible web-server")
.long("sourcegraph-server")
.takes_value(false),
)
.arg(
Arg::with_name("listen")
.help("Address to listen on")
.long("listen")
.takes_value(true),
)
.arg(Arg::with_name("filename").help("File to render").index(1))
.get_matches();
if matches.is_present("sourcegraph-server") {
highlighting_server(
matches
.value_of("listen")
.expect("Listening address is required for server mode"),
);
return;
}
let filename = matches.value_of("filename").expect("filename is required");
let stdin = io::stdin();
let mut in_handle = stdin.lock();
let stdout = io::stdout();
let mut out_handle = stdout.lock();
if matches.is_present("about-filter") && filename.ends_with(".md") {
format_markdown(&mut in_handle, &mut out_handle);
} else {
format_code(
&THEMES.themes["InspiredGitHub"],
&mut in_handle,
&mut out_handle,
filename,
);
}
}

144
tools/cheddar/src/main.rs → tools/cheddar/src/lib.rs
View file

@ -1,12 +1,10 @@
use clap::{App, Arg};
//! This file implements the rendering logic of cheddar with public
//! functions for syntax-highlighting code and for turning Markdown
//! into HTML with TVL extensions.
use comrak::arena_tree::Node;
use comrak::nodes::{Ast, AstNode, NodeCodeBlock, NodeHtmlBlock, NodeValue};
use comrak::{format_html, parse_document, Arena, ComrakOptions};
use lazy_static::lazy_static;
use rouille::Response;
use rouille::{router, try_or_400};
use serde::Deserialize;
use serde_json::json;
use std::cell::RefCell;
use std::collections::HashMap;
use std::env;
@ -29,11 +27,15 @@ use syntect::html::{
mod tests;
lazy_static! {
// Load syntaxes & themes lazily. Initialisation might not be
// required in the case of Markdown rendering (if there's no code
// blocks within the document).
// Load syntaxes lazily. Initialisation might not be required in
// the case of Markdown rendering (if there's no code blocks
// within the document).
//
// Note that the syntax set is included from the path pointed to
// by the BAT_SYNTAXES environment variable at compile time. This
// variable is populated by Nix and points to TVL's syntax set.
static ref SYNTAXES: SyntaxSet = from_binary(include_bytes!(env!("BAT_SYNTAXES")));
static ref THEMES: ThemeSet = ThemeSet::load_defaults();
pub static ref THEMES: ThemeSet = ThemeSet::load_defaults();
// Configure Comrak's Markdown rendering with all the bells &
// whistles!
@ -183,7 +185,7 @@ fn format_callout_paragraph(callout: Callout) -> NodeValue {
NodeValue::HtmlBlock(block)
}
fn format_markdown<R: BufRead, W: Write>(reader: &mut R, writer: &mut W) {
pub fn format_markdown<R: BufRead, W: Write>(reader: &mut R, writer: &mut W) {
let document = {
let mut buffer = String::new();
reader
@ -245,7 +247,7 @@ fn find_syntax_for_file(filename: &str) -> &'static SyntaxReference {
.unwrap_or_else(|| SYNTAXES.find_syntax_plain_text())
}
fn format_code<R: BufRead, W: Write>(
pub fn format_code<R: BufRead, W: Write>(
theme: &Theme,
reader: &mut R,
writer: &mut W,
@ -287,123 +289,3 @@ fn format_code<R: BufRead, W: Write>(
writeln!(writer, "</pre>").expect("write should not fail");
}
// Server endpoint for rendering the syntax of source code. This
// replaces the 'syntect_server' component of Sourcegraph.
fn code_endpoint(request: &rouille::Request) -> rouille::Response {
#[derive(Deserialize)]
struct SourcegraphQuery {
filepath: String,
theme: String,
code: String,
}
let query: SourcegraphQuery = try_or_400!(rouille::input::json_input(request));
let mut buf: Vec<u8> = Vec::new();
// We don't use syntect with the sourcegraph themes bundled
// currently, so let's fall back to something that is kind of
// similar (tm).
let theme = &THEMES.themes[match query.theme.as_str() {
"Sourcegraph (light)" => "Solarized (light)",
_ => "Solarized (dark)",
}];
format_code(theme, &mut query.code.as_bytes(), &mut buf, &query.filepath);
Response::json(&json!({
"is_plaintext": false,
"data": String::from_utf8_lossy(&buf)
}))
}
// Server endpoint for rendering a Markdown file.
fn markdown_endpoint(request: &rouille::Request) -> rouille::Response {
let mut texts: HashMap<String, String> = try_or_400!(rouille::input::json_input(request));
for text in texts.values_mut() {
let mut buf: Vec<u8> = Vec::new();
format_markdown(&mut text.as_bytes(), &mut buf);
*text = String::from_utf8_lossy(&buf).to_string();
}
Response::json(&texts)
}
fn highlighting_server(listen: &str) {
println!("Starting syntax highlighting server on '{}'", listen);
rouille::start_server(listen, move |request| {
router!(request,
// Markdown rendering route
(POST) (/markdown) => {
markdown_endpoint(request)
},
// Code rendering route
(POST) (/) => {
code_endpoint(request)
},
_ => {
rouille::Response::empty_404()
},
)
});
}
fn main() {
// Parse the command-line flags passed to cheddar to determine
// whether it is running in about-filter mode (`--about-filter`)
// and what file extension has been supplied.
let matches = App::new("cheddar")
.about("TVL's syntax highlighter")
.arg(
Arg::with_name("about-filter")
.help("Run as a cgit about-filter (renders Markdown)")
.long("about-filter")
.takes_value(false),
)
.arg(
Arg::with_name("sourcegraph-server")
.help("Run as a Sourcegraph compatible web-server")
.long("sourcegraph-server")
.takes_value(false),
)
.arg(
Arg::with_name("listen")
.help("Address to listen on")
.long("listen")
.takes_value(true),
)
.arg(Arg::with_name("filename").help("File to render").index(1))
.get_matches();
if matches.is_present("sourcegraph-server") {
highlighting_server(
matches
.value_of("listen")
.expect("Listening address is required for server mode"),
);
return;
}
let filename = matches.value_of("filename").expect("filename is required");
let stdin = io::stdin();
let mut in_handle = stdin.lock();
let stdout = io::stdout();
let mut out_handle = stdout.lock();
if matches.is_present("about-filter") && filename.ends_with(".md") {
format_markdown(&mut in_handle, &mut out_handle);
} else {
format_code(
&THEMES.themes["InspiredGitHub"],
&mut in_handle,
&mut out_handle,
filename,
);
}
}