fparkan/vendor/backtrace-ext/examples/miette.rs

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use std::fmt::Write;
use backtrace::Backtrace;
use miette::{Context, Diagnostic, Report};
use thiserror::Error;
type Result<T> = std::result::Result<T, Report>;
#[inline(never)]
fn main() {
set_panic_hook();
do_thing();
}
#[inline(never)]
fn do_thing() {
panic!("ooopssie!!!");
}
/// Tells miette to render panics using its rendering engine.
pub fn set_panic_hook() {
std::panic::set_hook(Box::new(move |info| {
let mut message = "Something went wrong".to_string();
let payload = info.payload();
if let Some(msg) = payload.downcast_ref::<&str>() {
message = msg.to_string();
}
if let Some(msg) = payload.downcast_ref::<String>() {
message = msg.clone();
}
let mut report: Result<()> = Err(Panic(message).into());
if let Some(loc) = info.location() {
report = report
.with_context(|| format!("at {}:{}:{}", loc.file(), loc.line(), loc.column()));
}
if let Err(err) = report.with_context(|| "Main thread panicked.".to_string()) {
eprintln!("Error: {:?}", err);
}
}));
}
#[derive(Debug, Error, Diagnostic)]
#[error("{0}{}", Panic::backtrace())]
#[diagnostic(help("set the `RUST_BACKTRACE=1` environment variable to display a backtrace."))]
struct Panic(String);
impl Panic {
fn backtrace() -> String {
if let Ok(var) = std::env::var("RUST_BACKTRACE") {
if !var.is_empty() && var != "0" {
const HEX_WIDTH: usize = std::mem::size_of::<usize>() + 2;
// Padding for next lines after frame's address
const NEXT_SYMBOL_PADDING: usize = HEX_WIDTH + 6;
let mut backtrace = String::new();
let trace = Backtrace::new();
let frames = backtrace_ext::short_frames_strict(&trace).enumerate();
for (idx, (frame, sub_frames)) in frames {
let ip = frame.ip();
let _ = write!(backtrace, "\n{:4}: {:2$?}", idx, ip, HEX_WIDTH);
let symbols = frame.symbols();
if symbols.is_empty() {
let _ = write!(backtrace, " - <unresolved>");
continue;
}
for (idx, symbol) in symbols[sub_frames].iter().enumerate() {
// Print symbols from this address,
// if there are several addresses
// we need to put it on next line
if idx != 0 {
let _ = write!(backtrace, "\n{:1$}", "", NEXT_SYMBOL_PADDING);
}
if let Some(name) = symbol.name() {
let _ = write!(backtrace, " - {}", name);
} else {
let _ = write!(backtrace, " - <unknown>");
}
// See if there is debug information with file name and line
if let (Some(file), Some(line)) = (symbol.filename(), symbol.lineno()) {
let _ = write!(
backtrace,
"\n{:3$}at {}:{}",
"",
file.display(),
line,
NEXT_SYMBOL_PADDING
);
}
}
}
return backtrace;
}
}
"".into()
}
}