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//! Types and function used to emit pretty diagnostics for `bindgen`.
//!
//! The entry point of this module is the [`Diagnostic`] type.
use std::fmt::Write;
use std::io::{self, BufRead, BufReader};
use std::{borrow::Cow, fs::File};
use annotate_snippets::{Renderer, Snippet};
pub(crate) use annotate_snippets::Level;
/// A `bindgen` diagnostic.
#[derive(Default)]
pub(crate) struct Diagnostic<'a> {
title: Option<(Cow<'a, str>, Level)>,
slices: Vec<Slice<'a>>,
footer: Vec<(Cow<'a, str>, Level)>,
}
impl<'a> Diagnostic<'a> {
/// Add a title to the diagnostic and set its type.
pub(crate) fn with_title(
&mut self,
title: impl Into<Cow<'a, str>>,
level: Level,
) -> &mut Self {
self.title = Some((title.into(), level));
self
}
/// Add a slice of source code to the diagnostic.
pub(crate) fn add_slice(&mut self, slice: Slice<'a>) -> &mut Self {
self.slices.push(slice);
self
}
/// Add a footer annotation to the diagnostic. This annotation will have its own type.
pub(crate) fn add_annotation(
&mut self,
msg: impl Into<Cow<'a, str>>,
level: Level,
) -> &mut Self {
self.footer.push((msg.into(), level));
self
}
/// Print this diagnostic.
///
/// The diagnostic is printed using `cargo:warning` if `bindgen` is being invoked by a build
/// script or using `eprintln` otherwise.
pub(crate) fn display(&self) {
std::thread_local! {
static INVOKED_BY_BUILD_SCRIPT: bool = std::env::var_os("CARGO_CFG_TARGET_ARCH").is_some();
}
let mut footer = vec![];
let mut slices = vec![];
let snippet = if let Some((msg, level)) = &self.title {
(*level).title(msg)
} else {
return;
};
for (msg, level) in &self.footer {
footer.push((*level).title(msg));
}
// add additional info that this is generated by bindgen
// so as to not confuse with rustc warnings
footer.push(
Level::Info.title("This diagnostic was generated by bindgen."),
);
for slice in &self.slices {
if let Some(source) = &slice.source {
let mut snippet = Snippet::source(source)
.line_start(slice.line.unwrap_or_default());
if let Some(origin) = &slice.filename {
snippet = snippet.origin(origin);
}
slices.push(snippet);
}
}
let renderer = Renderer::styled();
let dl = renderer.render(snippet.snippets(slices).footers(footer));
if INVOKED_BY_BUILD_SCRIPT.with(Clone::clone) {
// This is just a hack which hides the `warning:` added by cargo at the beginning of
// every line. This should be fine as our diagnostics already have a colorful title.
// FIXME (pvdrz): Could it be that this doesn't work in other languages?
let hide_warning = "\r \r";
let string = dl.to_string();
for line in string.lines() {
println!("cargo:warning={hide_warning}{line}");
}
} else {
eprintln!("{dl}\n");
}
}
}
/// A slice of source code.
#[derive(Default)]
pub(crate) struct Slice<'a> {
source: Option<Cow<'a, str>>,
filename: Option<String>,
line: Option<usize>,
}
impl<'a> Slice<'a> {
/// Set the source code.
pub(crate) fn with_source(
&mut self,
source: impl Into<Cow<'a, str>>,
) -> &mut Self {
self.source = Some(source.into());
self
}
/// Set the file, line and column.
pub(crate) fn with_location(
&mut self,
mut name: String,
line: usize,
col: usize,
) -> &mut Self {
write!(name, ":{line}:{col}").expect("Writing to a string cannot fail");
self.filename = Some(name);
self.line = Some(line);
self
}
}
pub(crate) fn get_line(
filename: &str,
line: usize,
) -> io::Result<Option<String>> {
let file = BufReader::new(File::open(filename)?);
if let Some(line) = file.lines().nth(line.wrapping_sub(1)) {
return line.map(Some);
}
Ok(None)
}