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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::{
display_list::{DisplayList, FormatOptions},
snippet::{Annotation, Slice as ExtSlice, Snippet},
};
use annotate_snippets::snippet::AnnotationType;
#[derive(Clone, Copy, Debug)]
pub(crate) enum Level {
Error,
Warn,
Info,
Note,
Help,
}
impl From<Level> for AnnotationType {
fn from(level: Level) -> Self {
match level {
Level::Error => Self::Error,
Level::Warn => Self::Warning,
Level::Info => Self::Info,
Level::Note => Self::Note,
Level::Help => Self::Help,
}
}
}
/// 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 title = None;
let mut footer = vec![];
let mut slices = vec![];
if let Some((msg, level)) = &self.title {
title = Some(Annotation {
id: Some("bindgen"),
label: Some(msg.as_ref()),
annotation_type: (*level).into(),
})
}
for (msg, level) in &self.footer {
footer.push(Annotation {
id: None,
label: Some(msg.as_ref()),
annotation_type: (*level).into(),
});
}
// add additional info that this is generated by bindgen
// so as to not confuse with rustc warnings
footer.push(Annotation {
id: None,
label: Some("This diagnostic was generated by bindgen."),
annotation_type: AnnotationType::Info,
});
for slice in &self.slices {
if let Some(source) = &slice.source {
slices.push(ExtSlice {
source: source.as_ref(),
line_start: slice.line.unwrap_or_default(),
origin: slice.filename.as_deref(),
annotations: vec![],
fold: false,
})
}
}
let snippet = Snippet {
title,
footer,
slices,
opt: FormatOptions {
color: true,
..Default::default()
},
};
let dl = DisplayList::from(snippet);
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!("{}\n", dl);
}
}
}
/// 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)
}