openethereum/util/src/panics.rs
Tomasz Drwięga f724cab92d Merge branch 'master' into updating_clippy
Conflicts:
	ethcore/src/lib.rs
	sync/src/chain.rs
	sync/src/lib.rs
	util/src/keys/store.rs
	util/src/lib.rs
2016-03-11 19:17:09 +01:00

190 lines
4.9 KiB
Rust

// Copyright 2015, 2016 Ethcore (UK) Ltd.
// This file is part of Parity.
// Parity is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// Parity is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with Parity. If not, see <http://www.gnu.org/licenses/>.
//! Panic utilities
use std::thread;
use std::ops::DerefMut;
use std::sync::{Arc, Mutex};
use std::default::Default;
/// Thread-safe closure for handling possible panics
pub trait OnPanicListener: Send + Sync + 'static {
/// Invoke listener
fn call(&mut self, arg: &str);
}
/// Forwards panics from child
pub trait ForwardPanic {
/// Attach `on_panic` listener to `child` and rethrow all panics
fn forward_from<S>(&self, child: &S) where S : MayPanic;
}
/// Trait indicating that the structure catches some of the panics (most probably from spawned threads)
/// and it's possbile to be notified when one of the threads panics.
pub trait MayPanic {
/// `closure` will be invoked whenever panic in thread is caught
fn on_panic<F>(&self, closure: F) where F: OnPanicListener;
}
struct PanicGuard<'a> {
handler: &'a PanicHandler,
}
impl<'a> Drop for PanicGuard<'a> {
fn drop(&mut self) {
if thread::panicking() {
self.handler.notify_all("Panic!".to_owned());
}
}
}
/// Structure that allows to catch panics and notify listeners
pub struct PanicHandler {
listeners: Mutex<Vec<Box<OnPanicListener>>>
}
impl Default for PanicHandler {
fn default() -> Self {
PanicHandler::new()
}
}
impl PanicHandler {
/// Creates new `PanicHandler` wrapped in `Arc`
pub fn new_in_arc() -> Arc<Self> {
Arc::new(Self::new())
}
/// Creates new `PanicHandler`
pub fn new() -> Self {
PanicHandler {
listeners: Mutex::new(vec![])
}
}
/// Invoke closure and catch any possible panics.
/// In case of panic notifies all listeners about it.
#[cfg_attr(feature="dev", allow(deprecated))]
pub fn catch_panic<G, R>(&self, g: G) -> thread::Result<R> where G: FnOnce() -> R + Send + 'static {
let _guard = PanicGuard { handler: self };
let result = g();
Ok(result)
}
fn notify_all(&self, r: String) {
let mut listeners = self.listeners.lock().unwrap();
for listener in listeners.deref_mut() {
listener.call(&r);
}
}
}
impl MayPanic for PanicHandler {
fn on_panic<F>(&self, closure: F) where F: OnPanicListener {
self.listeners.lock().unwrap().push(Box::new(closure));
}
}
impl ForwardPanic for Arc<PanicHandler> {
fn forward_from<S>(&self, child: &S) where S : MayPanic {
let p = self.clone();
child.on_panic(move |t| p.notify_all(t));
}
}
impl<F> OnPanicListener for F
where F: FnMut(String) + Send + Sync + 'static {
fn call(&mut self, arg: &str) {
self(arg.to_owned())
}
}
#[test]
#[ignore] // panic forwarding doesnt work on the same thread in beta
fn should_notify_listeners_about_panic () {
use std::sync::RwLock;
// given
let invocations = Arc::new(RwLock::new(vec![]));
let i = invocations.clone();
let p = PanicHandler::new();
p.on_panic(move |t| i.write().unwrap().push(t));
// when
p.catch_panic(|| panic!("Panic!")).unwrap_err();
// then
assert!(invocations.read().unwrap()[0] == "Panic!");
}
#[test]
#[ignore] // panic forwarding doesnt work on the same thread in beta
fn should_notify_listeners_about_panic_when_string_is_dynamic () {
use std::sync::RwLock;
// given
let invocations = Arc::new(RwLock::new(vec![]));
let i = invocations.clone();
let p = PanicHandler::new();
p.on_panic(move |t| i.write().unwrap().push(t));
// when
p.catch_panic(|| panic!("Panic: {}", 1)).unwrap_err();
// then
assert!(invocations.read().unwrap()[0] == "Panic: 1");
}
#[test]
fn should_notify_listeners_about_panic_in_other_thread () {
use std::thread;
use std::sync::RwLock;
// given
let invocations = Arc::new(RwLock::new(vec![]));
let i = invocations.clone();
let p = PanicHandler::new();
p.on_panic(move |t| i.write().unwrap().push(t));
// when
let t = thread::spawn(move ||
p.catch_panic(|| panic!("Panic!")).unwrap()
);
t.join().unwrap_err();
// then
assert!(invocations.read().unwrap()[0] == "Panic!");
}
#[test]
#[ignore] // panic forwarding doesnt work on the same thread in beta
fn should_forward_panics () {
use std::sync::RwLock;
// given
let invocations = Arc::new(RwLock::new(vec![]));
let i = invocations.clone();
let p = PanicHandler::new_in_arc();
p.on_panic(move |t| i.write().unwrap().push(t));
let p2 = PanicHandler::new();
p.forward_from(&p2);
// when
p2.catch_panic(|| panic!("Panic!")).unwrap_err();
// then
assert!(invocations.read().unwrap()[0] == "Panic!");
}