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use crate::nop_lib::Nop;
use clap::{Arg, ArgMatches, Command};
use mdbook::book::Book;
use mdbook::errors::Error;
use mdbook::preprocess::{CmdPreprocessor, Preprocessor, PreprocessorContext};
use semver::{Version, VersionReq};
use std::io;
use std::process;
pub fn make_app() -> Command {
Command::new("nop-preprocessor")
.about("A mdbook preprocessor which does precisely nothing")
.subcommand(
Command::new("supports")
.arg(Arg::new("renderer").required(true))
.about("Check whether a renderer is supported by this preprocessor"),
)
}
fn main() {
let matches = make_app().get_matches();
// Users will want to construct their own preprocessor here
let preprocessor = Nop::new();
if let Some(sub_args) = matches.subcommand_matches("supports") {
handle_supports(&preprocessor, sub_args);
} else if let Err(e) = handle_preprocessing(&preprocessor) {
eprintln!("{e}");
process::exit(1);
}
}
fn handle_preprocessing(pre: &dyn Preprocessor) -> Result<(), Error> {
let (ctx, book) = CmdPreprocessor::parse_input(io::stdin())?;
let book_version = Version::parse(&ctx.mdbook_version)?;
let version_req = VersionReq::parse(mdbook::MDBOOK_VERSION)?;
if !version_req.matches(&book_version) {
eprintln!(
"Warning: The {} plugin was built against version {} of mdbook, \
but we're being called from version {}",
pre.name(),
mdbook::MDBOOK_VERSION,
ctx.mdbook_version
);
}
let processed_book = pre.run(&ctx, book)?;
serde_json::to_writer(io::stdout(), &processed_book)?;
Ok(())
}
fn handle_supports(pre: &dyn Preprocessor, sub_args: &ArgMatches) -> ! {
let renderer = sub_args
.get_one::<String>("renderer")
.expect("Required argument");
let supported = pre.supports_renderer(renderer);
// Signal whether the renderer is supported by exiting with 1 or 0.
if supported {
process::exit(0);
} else {
process::exit(1);
}
}
/// The actual implementation of the `Nop` preprocessor. This would usually go
/// in your main `lib.rs` file.
mod nop_lib {
use super::*;
/// A no-op preprocessor.
pub struct Nop;
impl Nop {
pub fn new() -> Nop {
Nop
}
}
impl Preprocessor for Nop {
fn name(&self) -> &str {
"nop-preprocessor"
}
fn run(&self, ctx: &PreprocessorContext, book: Book) -> Result<Book, Error> {
// In testing we want to tell the preprocessor to blow up by setting a
// particular config value
if let Some(nop_cfg) = ctx.config.get_preprocessor(self.name()) {
if nop_cfg.contains_key("blow-up") {
anyhow::bail!("Boom!!1!");
}
}
// we *are* a no-op preprocessor after all
Ok(book)
}
fn supports_renderer(&self, renderer: &str) -> bool {
renderer != "not-supported"
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn nop_preprocessor_run() {
let input_json = r##"[
{
"root": "/path/to/book",
"config": {
"book": {
"authors": ["AUTHOR"],
"language": "en",
"multilingual": false,
"src": "src",
"title": "TITLE"
},
"preprocessor": {
"nop": {}
}
},
"renderer": "html",
"mdbook_version": "0.4.21"
},
{
"sections": [
{
"Chapter": {
"name": "Chapter 1",
"content": "# Chapter 1\n",
"number": [1],
"sub_items": [],
"path": "chapter_1.md",
"source_path": "chapter_1.md",
"parent_names": []
}
}
],
"__non_exhaustive": null
}
]"##;
let input_json = input_json.as_bytes();
let (ctx, book) = mdbook::preprocess::CmdPreprocessor::parse_input(input_json).unwrap();
let expected_book = book.clone();
let result = Nop::new().run(&ctx, book);
assert!(result.is_ok());
// The nop-preprocessor should not have made any changes to the book content.
let actual_book = result.unwrap();
assert_eq!(actual_book, expected_book);
}
}
}
|
