std: Rename thread::catch_panic to panic::recover

This commit is an implementation of [RFC 1236][rfc] which renames the
`thread::catch_panic` function to `panic::recover` while also removing the
`Send` bound (but leaving the `'static` bound).

[rfc]: rust-lang/rfcs#1236

cc rust-lang#27719

src/libstd/lib.rs

@@ -365,6 +365,7 @@ pub mod fs;
 pub mod io;
 pub mod net;
 pub mod os;
+pub mod panic;
 pub mod path;
 pub mod process;
 pub mod sync;

src/libstd/panic.rs

@@ -0,0 +1,63 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Panic support in the standard library
+
+#![unstable(feature = "std_panic", reason = "module recently added",
+            issue = "27719")]
+
+use thread::Result;
+
+/// Invokes a closure, capturing the cause of panic if one occurs.
+///
+/// This function will return `Ok` with the closure's result if the closure
+/// does not panic, and will return `Err(cause)` if the closure panics. The
+/// `cause` returned is the object with which panic was originally invoked.
+///
+/// It is currently undefined behavior to unwind from Rust code into foreign
+/// code, so this function is particularly useful when Rust is called from
+/// another language (normally C). This can run arbitrary Rust code, capturing a
+/// panic and allowing a graceful handling of the error.
+///
+/// It is **not** recommended to use this function for a general try/catch
+/// mechanism. The `Result` type is more appropriate to use for functions that
+/// can fail on a regular basis.
+///
+/// The closure provided is required to adhere to the `'static` bound to ensure
+/// that it cannot reference data in the parent stack frame, mitigating problems
+/// with exception safety.
+///
+/// # Examples
+///
+/// ```
+/// #![feature(recover, std_panic)]
+///
+/// use std::panic;
+///
+/// let result = panic::recover(|| {
+///     println!("hello!");
+/// });
+/// assert!(result.is_ok());
+///
+/// let result = panic::recover(|| {
+///     panic!("oh no!");
+/// });
+/// assert!(result.is_err());
+/// ```
+#[unstable(feature = "recover", reason = "recent API addition",
+           issue = "27719")]
+pub fn recover<F, R>(f: F) -> Result<R> where F: FnOnce() -> R + 'static {
+    let mut result = None;
+    unsafe {
+        let result = &mut result;
+        try!(::rt::unwind::try(move || *result = Some(f())))
+    }
+    Ok(result.unwrap())
+}

src/libstd/rt/mod.rs

@@ -22,9 +22,9 @@
             issue = "0")]
 #![allow(missing_docs)]
 
+use panic;
 use prelude::v1::*;
 use sys;
-use thread;
 
 // Reexport some of our utilities which are expected by other crates.
 pub use self::util::min_stack;
@@ -96,7 +96,7 @@ fn lang_start(main: *const u8, argc: isize, argv: *const *const u8) -> isize {
         args::init(argc, argv);
 
         // And finally, let's run some code!
-        let res = thread::catch_panic(mem::transmute::<_, fn()>(main));
+        let res = panic::recover(mem::transmute::<_, fn()>(main));
         cleanup();
         res.is_err()
     };

src/libstd/thread/mod.rs

@@ -357,26 +357,9 @@ pub fn panicking() -> bool {
 /// with exception safety. Furthermore, a `Send` bound is also required,
 /// providing the same safety guarantees as `thread::spawn` (ensuring the
 /// closure is properly isolated from the parent).
-///
-/// # Examples
-///
-/// ```
-/// #![feature(catch_panic)]
-///
-/// use std::thread;
-///
-/// let result = thread::catch_panic(|| {
-///     println!("hello!");
-/// });
-/// assert!(result.is_ok());
-///
-/// let result = thread::catch_panic(|| {
-///     panic!("oh no!");
-/// });
-/// assert!(result.is_err());
-/// ```
 #[unstable(feature = "catch_panic", reason = "recent API addition",
            issue = "27719")]
+#[deprecated(since = "1.4.0", reason = "renamed to std::panic::recover")]
 pub fn catch_panic<F, R>(f: F) -> Result<R>
     where F: FnOnce() -> R + Send + 'static
 {

src/test/run-pass/binary-heap-panic-safe.rs

@@ -8,10 +8,10 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(std_misc, collections, catch_panic, rand, sync_poison)]
+#![feature(collections, recover, std_panic, rand)]
 
 use std::__rand::{thread_rng, Rng};
-use std::thread;
+use std::panic;
 
 use std::collections::BinaryHeap;
 use std::cmp;
@@ -74,7 +74,7 @@ fn test_integrity() {
 
 
                 // push the panicking item to the heap and catch the panic
-                let thread_result = thread::catch_panic(move || {
+                let thread_result = panic::recover(move || {
                     heap.lock().unwrap().push(panic_item);
                 });
                 assert!(thread_result.is_err());

src/test/run-pass/running-with-no-runtime.rs

@@ -8,11 +8,11 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(catch_panic, start)]
+#![feature(std_panic, recover, start)]
 
 use std::ffi::CStr;
 use std::process::{Command, Output};
-use std::thread;
+use std::panic;
 use std::str;
 
 #[start]
@@ -22,8 +22,8 @@ fn start(argc: isize, argv: *const *const u8) -> isize {
             match **argv.offset(1) as char {
                 '1' => {}
                 '2' => println!("foo"),
-                '3' => assert!(thread::catch_panic(|| {}).is_ok()),
-                '4' => assert!(thread::catch_panic(|| panic!()).is_err()),
+                '3' => assert!(panic::recover(|| {}).is_ok()),
+                '4' => assert!(panic::recover(|| panic!()).is_err()),
                 '5' => assert!(Command::new("test").spawn().is_err()),
                 _ => panic!()
             }