Replace Signal::from_c_int by Signal::try_from

TryFrom wasn't stable when that function was written.

Author: asomers

CHANGELOG.md

@@ -6,6 +6,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ## [Unreleased] - ReleaseDate
 ### Added
 ### Changed
+- `Signal::from_c_int` has been replaced by `Signal::try_from`
+  ([#1113](https://github.com/nix-rust/nix/pull/1113))
+
 - Changed `readlink` and `readlinkat` to return `OsString`
   ([#1109](https://github.com/nix-rust/nix/pull/1109))
 

src/sys/signal.rs

@@ -6,6 +6,7 @@
 use libc;
 use {Error, Result};
 use errno::Errno;
+use std::convert::TryFrom;
 use std::mem;
 use std::fmt;
 use std::str::FromStr;
@@ -288,12 +289,12 @@ impl Signal {
     pub fn iterator() -> SignalIterator {
         SignalIterator{next: 0}
     }
+}
+
+impl TryFrom<libc::c_int> for Signal {
+    type Error = Error;
 
-    // We do not implement the From trait, because it is supposed to be infallible.
-    // With Rust RFC 1542 comes the appropriate trait TryFrom. Once it is
-    // implemented, we'll replace this function.
-    #[inline]
-    pub fn from_c_int(signum: libc::c_int) -> Result<Signal> {
+    fn try_from(signum: libc::c_int) -> Result<Signal> {
         if 0 < signum && signum < NSIG {
             Ok(unsafe { mem::transmute(signum) })
         } else {
@@ -413,7 +414,7 @@ impl SigSet {
         let mut signum: libc::c_int = unsafe { mem::uninitialized() };
         let res = unsafe { libc::sigwait(&self.sigset as *const libc::sigset_t, &mut signum) };
 
-        Errno::result(res).map(|_| Signal::from_c_int(signum).unwrap())
+        Errno::result(res).map(|_| Signal::try_from(signum).unwrap())
     }
 }
 
@@ -536,14 +537,15 @@ pub unsafe fn sigaction(signal: Signal, sigaction: &SigAction) -> Result<SigActi
 /// # #[macro_use] extern crate lazy_static;
 /// # extern crate libc;
 /// # extern crate nix;
+/// # use std::convert::TryFrom;
 /// # use std::sync::atomic::{AtomicBool, Ordering};
 /// # use nix::sys::signal::{self, Signal, SigHandler};
 /// lazy_static! {
 ///    static ref SIGNALED: AtomicBool = AtomicBool::new(false);
 /// }
 ///
 /// extern fn handle_sigint(signal: libc::c_int) {
-///     let signal = Signal::from_c_int(signal).unwrap();
+///     let signal = Signal::try_from(signal).unwrap();
 ///     SIGNALED.store(signal == Signal::SIGINT, Ordering::Relaxed);
 /// }
 ///

src/sys/wait.rs

@@ -1,6 +1,7 @@
 use libc::{self, c_int};
 use Result;
 use errno::Errno;
+use std::convert::TryFrom;
 use unistd::Pid;
 
 use sys::signal::Signal;
@@ -126,7 +127,7 @@ fn signaled(status: i32) -> bool {
 }
 
 fn term_signal(status: i32) -> Result<Signal> {
-    Signal::from_c_int(unsafe { libc::WTERMSIG(status) })
+    Signal::try_from(unsafe { libc::WTERMSIG(status) })
 }
 
 fn dumped_core(status: i32) -> bool {
@@ -138,7 +139,7 @@ fn stopped(status: i32) -> bool {
 }
 
 fn stop_signal(status: i32) -> Result<Signal> {
-    Signal::from_c_int(unsafe { libc::WSTOPSIG(status) })
+    Signal::try_from(unsafe { libc::WSTOPSIG(status) })
 }
 
 #[cfg(any(target_os = "android", target_os = "linux"))]

test/sys/test_signal.rs

@@ -2,6 +2,7 @@ use libc;
 use nix::Error;
 use nix::sys::signal::*;
 use nix::unistd::*;
+use std::convert::TryFrom;
 use std::sync::atomic::{AtomicBool, Ordering};
 
 #[test]
@@ -75,7 +76,7 @@ lazy_static! {
 }
 
 extern fn test_sigaction_handler(signal: libc::c_int) {
-    let signal = Signal::from_c_int(signal).unwrap();
+    let signal = Signal::try_from(signal).unwrap();
     SIGNALED.store(signal == Signal::SIGINT, Ordering::Relaxed);
 }
 

test/sys/test_signalfd.rs

@@ -1,3 +1,5 @@
+use std::convert::TryFrom;
+
 #[test]
 fn test_signalfd() {
     use nix::sys::signalfd::SignalFd;
@@ -20,6 +22,6 @@ fn test_signalfd() {
 
     // And now catch that same signal.
     let res = fd.read_signal().unwrap().unwrap();
-    let signo = Signal::from_c_int(res.ssi_signo as i32).unwrap();
+    let signo = Signal::try_from(res.ssi_signo as i32).unwrap();
     assert_eq!(signo, signal::SIGUSR1);
 }