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Rename panic handlers to panic hook
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sfackler committed Mar 16, 2016
1 parent 74dfc1d commit 159eae8
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Showing 2 changed files with 46 additions and 33 deletions.
16 changes: 15 additions & 1 deletion src/libstd/panic.rs
Expand Up @@ -23,7 +23,21 @@ use sync::{Arc, Mutex, RwLock};
use sys_common::unwind;
use thread::Result;

pub use panicking::{take_handler, set_handler, PanicInfo, Location};
pub use panicking::{take_hook, set_hook, PanicInfo, Location};

///
#[rustc_deprecated(since = "1.9.0", reason = "renamed to set_hook")]
#[unstable(feature = "panic_handler", reason = "awaiting feedback", issue = "30449")]
pub fn set_handler<F>(handler: F) where F: Fn(&PanicInfo) + 'static + Sync + Send {
set_hook(handler)
}

///
#[rustc_deprecated(since = "1.9.0", reason = "renamed to take_hook")]
#[unstable(feature = "panic_handler", reason = "awaiting feedback", issue = "30449")]
pub fn take_handler() -> Box<Fn(&PanicInfo) + 'static + Sync + Send> {
take_hook()
}

/// A marker trait which represents "panic safe" types in Rust.
///
Expand Down
63 changes: 31 additions & 32 deletions src/libstd/panicking.rs
Expand Up @@ -32,73 +32,72 @@ thread_local! {
}

#[derive(Copy, Clone)]
enum Handler {
enum Hook {
Default,
Custom(*mut (Fn(&PanicInfo) + 'static + Sync + Send)),
}

static HANDLER_LOCK: StaticRwLock = StaticRwLock::new();
static mut HANDLER: Handler = Handler::Default;
static HOOK_LOCK: StaticRwLock = StaticRwLock::new();
static mut HOOK: Hook = Hook::Default;
static FIRST_PANIC: AtomicBool = AtomicBool::new(true);

/// Registers a custom panic handler, replacing any that was previously
/// registered.
/// Registers a custom panic hook, replacing any that was previously registered.
///
/// The panic handler is invoked when a thread panics, but before it begins
/// unwinding the stack. The default handler prints a message to standard error
/// The panic hook is invoked when a thread panics, but before it begins
/// unwinding the stack. The default hook prints a message to standard error
/// and generates a backtrace if requested, but this behavior can be customized
/// with the `set_handler` and `take_handler` functions.
/// with the `set_hook` and `take_hook` functions.
///
/// The handler is provided with a `PanicInfo` struct which contains information
/// The hook is provided with a `PanicInfo` struct which contains information
/// about the origin of the panic, including the payload passed to `panic!` and
/// the source code location from which the panic originated.
///
/// The panic handler is a global resource.
/// The panic hook is a global resource.
///
/// # Panics
///
/// Panics if called from a panicking thread.
#[unstable(feature = "panic_handler", reason = "awaiting feedback", issue = "30449")]
pub fn set_handler<F>(handler: F) where F: Fn(&PanicInfo) + 'static + Sync + Send {
pub fn set_hook<F>(hook: F) where F: Fn(&PanicInfo) + 'static + Sync + Send {
if thread::panicking() {
panic!("cannot modify the panic handler from a panicking thread");
panic!("cannot modify the panic hook from a panicking thread");
}

let handler = Box::new(handler);
let hook = Box::new(hook);
unsafe {
let lock = HANDLER_LOCK.write();
let old_handler = HANDLER;
HANDLER = Handler::Custom(Box::into_raw(handler));
let lock = HOOK_LOCK.write();
let old_hook = HOOK;
HOOK = Hook::Custom(Box::into_raw(hook));
drop(lock);

if let Handler::Custom(ptr) = old_handler {
if let Hook::Custom(ptr) = old_hook {
Box::from_raw(ptr);
}
}
}

/// Unregisters the current panic handler, returning it.
/// Unregisters the current panic hook, returning it.
///
/// If no custom handler is registered, the default handler will be returned.
/// If no custom hook is registered, the default hook will be returned.
///
/// # Panics
///
/// Panics if called from a panicking thread.
#[unstable(feature = "panic_handler", reason = "awaiting feedback", issue = "30449")]
pub fn take_handler() -> Box<Fn(&PanicInfo) + 'static + Sync + Send> {
pub fn take_hook() -> Box<Fn(&PanicInfo) + 'static + Sync + Send> {
if thread::panicking() {
panic!("cannot modify the panic handler from a panicking thread");
panic!("cannot modify the panic hook from a panicking thread");
}

unsafe {
let lock = HANDLER_LOCK.write();
let handler = HANDLER;
HANDLER = Handler::Default;
let lock = HOOK_LOCK.write();
let hook = HOOK;
HOOK = Hook::Default;
drop(lock);

match handler {
Handler::Default => Box::new(default_handler),
Handler::Custom(ptr) => {Box::from_raw(ptr)} // FIXME #30530
match hook {
Hook::Default => Box::new(default_hook),
Hook::Custom(ptr) => {Box::from_raw(ptr)} // FIXME #30530
}
}
}
Expand Down Expand Up @@ -151,7 +150,7 @@ impl<'a> Location<'a> {
}
}

fn default_handler(info: &PanicInfo) {
fn default_hook(info: &PanicInfo) {
let panics = PANIC_COUNT.with(|s| s.get());

// If this is a double panic, make sure that we print a backtrace
Expand Down Expand Up @@ -224,10 +223,10 @@ pub fn on_panic(obj: &(Any+Send), file: &'static str, line: u32) {
};

unsafe {
let _lock = HANDLER_LOCK.read();
match HANDLER {
Handler::Default => default_handler(&info),
Handler::Custom(ptr) => (*ptr)(&info),
let _lock = HOOK_LOCK.read();
match HOOK {
Hook::Default => default_hook(&info),
Hook::Custom(ptr) => (*ptr)(&info),
}
}

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