mirror of
https://github.com/haraldh/chainerror.git
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55 lines
1.3 KiB
Rust
55 lines
1.3 KiB
Rust
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/*!
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~~~bash
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$ cargo run -q --example tutorial9
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Func1ErrorFunc2:
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examples/tutorial9.rs:37: Func1ErrorFunc2(func1 error calling func2)
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Caused by:
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examples/tutorial9.rs:29: Func2Error(Error reading 'foo.txt')
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Caused by:
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Kind(NotFound)
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~~~
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!*/
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use chainerror::prelude::*;
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use std::error::Error;
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use std::io;
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use std::result::Result;
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fn do_some_io() -> Result<(), Box<Error>> {
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Err(io::Error::from(io::ErrorKind::NotFound))?;
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Ok(())
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}
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derive_str_cherr!(Func2Error);
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fn func2() -> Result<(), Box<Error>> {
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let filename = "foo.txt";
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do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
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Ok(())
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}
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derive_str_cherr!(Func1ErrorFunc2);
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derive_str_cherr!(Func1ErrorIO);
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fn func1() -> Result<(), Box<Error>> {
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func2().map_err(mstrerr!(Func1ErrorFunc2, "func1 error calling func2"))?;
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let filename = "bar.txt";
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do_some_io().map_err(mstrerr!(Func1ErrorIO, "Error reading '{}'", filename))?;
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Ok(())
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}
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fn main() -> Result<(), Box<Error>> {
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if let Err(e) = func1() {
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if let Some(s) = e.downcast_ref::<ChainError<Func1ErrorIO>>() {
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eprintln!("Func1ErrorIO:\n{:?}", s);
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}
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if let Some(s) = try_cherr_ref!(e, Func1ErrorFunc2) {
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eprintln!("Func1ErrorFunc2:\n{:?}", s);
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}
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}
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Ok(())
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}
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