Crate trace_error [−] [src]
Extensions to Rust's error system to automatically include backtraces to the exact location an error originates.
Consider this a more lightweight and less macro-based alternative to error_chain
and similar crates. This crate
does not take care of actually defining the errors and their varieties, but only focuses on a thin container
for holding the errors and a backtrace to their origin.
Trace
and TraceResult
should usually be used in place of Result
using the macros
throw!
, try_throw!
, and try_rethrow!
Although the ?
syntax was just introduced, trace-error
is not yet compatible with it until the Carrier
trait is stabilized. As a result,
all instances of try!
and ?
should be replaced with try_throw!
if you intend to use this crate to its fullest.
Example:
#[macro_use] extern crate trace_error; use std::error::Error; use std::fmt::{Display, Formatter, Result as FmtResult}; use std::io; use std::fs::File; use trace_error::*; pub type MyResultType<T> = TraceResult<T, MyErrorType>; #[derive(Debug)] pub enum MyErrorType { Io(io::Error), ErrorOne, ErrorTwo, //etc } impl Display for MyErrorType { fn fmt(&self, f: &mut Formatter) -> FmtResult { write!(f, "{}", self.description()) } } impl Error for MyErrorType { fn description(&self) -> &str { match *self { MyErrorType::Io(ref err) => err.description(), MyErrorType::ErrorOne => "Error One", MyErrorType::ErrorTwo => "Error Two", } } } impl From<io::Error> for MyErrorType { fn from(err: io::Error) -> MyErrorType { MyErrorType::Io(err) } } fn basic() -> MyResultType<i32> { //Something may throw throw!(MyErrorType::ErrorOne); // Or return an Ok value Ok(42) } fn example() -> MyResultType<()> { // Note the use of try_rethrow! for TraceResult results let meaning = try_rethrow!(basic()); // Prints 42 if `basic` succeeds println!("{}", meaning); // Note the use of try_throw! for non-TraceResult results let some_file = try_throw!(File::open("Cargo.toml")); Ok(()) } fn main() { match example() { Ok(_) => println!("Success!"), // Here, err is the Trace<E>, which can be printed normally, // showing both the error and the backtrace. Err(err) => panic!("Error: {}", err) } }
Modules
backtrace |
Small extensions to the |
Macros
backtrace |
Returns a string containing the formatted backtrace and a header message |
backtrace_noheader |
Variation of |
throw |
Creates a new |
try_rethrow |
Like |
try_throw |
Like |
Structs
Trace |
Trace error that encapsulates a backtrace alongside an error value. |
Type Definitions
TraceResult |
Alias to aid in usage with |