Merge #1113

1113: Libc enum tryfrom r=asomers a=asomers



Co-authored-by: Alan Somers <asomers@gmail.com>

6 files changed, 29 insertions, 71 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 88b014e1..e72e5517 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
   ([#1107](https://github.com/nix-rust/nix/pull/1107))
 
 ### 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+- `Signal::from_c_int` has been replaced by `Signal::try_from`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))
 
diff --git a/src/macros.rs b/src/macros.rs
index 7ec00c86..5fb49e3b 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -81,9 +81,10 @@ macro_rules! libc_bitflags {
 /// }
 /// ```
 macro_rules! libc_enum {
-    // (non-pub) Exit rule.
+    // Exit rule.
     (@make_enum
         {
+            $v:vis
             name: $BitFlags:ident,
             attrs: [$($attrs:tt)*],
             entries: [$($entries:tt)*],
@@ -91,49 +92,15 @@ macro_rules! libc_enum {
     ) => {
         $($attrs)*
         #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
-        enum $BitFlags {
+        $v enum $BitFlags {
             $($entries)*
         }
     };
 
-    // (pub) Exit rule.
-    (@make_enum
-        {
-            pub,
-            name: $BitFlags:ident,
-            attrs: [$($attrs:tt)*],
-            entries: [$($entries:tt)*],
-        }
-    ) => {
-        $($attrs)*
-        #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
-        pub enum $BitFlags {
-            $($entries)*
-        }
-    };
-
-    // (non-pub) Done accumulating.
-    (@accumulate_entries
-        {
-            name: $BitFlags:ident,
-            attrs: $attrs:tt,
-        },
-        $entries:tt;
-    ) => {
-        libc_enum! {
-            @make_enum
-            {
-                name: $BitFlags,
-                attrs: $attrs,
-                entries: $entries,
-            }
-        }
-    };
-
-    // (pub) Done accumulating.
+    // Done accumulating.
     (@accumulate_entries
         {
-            pub,
+            $v:vis
             name: $BitFlags:ident,
             attrs: $attrs:tt,
         },
@@ -142,7 +109,7 @@ macro_rules! libc_enum {
         libc_enum! {
             @make_enum
             {
-                pub,
+                $v
                 name: $BitFlags,
                 attrs: $attrs,
                 entries: $entries,
@@ -217,35 +184,17 @@ macro_rules! libc_enum {
         }
     };
 
-    // (non-pub) Entry rule.
-    (
-        $(#[$attr:meta])*
-        enum $BitFlags:ident {
-            $($vals:tt)*
-        }
-    ) => {
-        libc_enum! {
-            @accumulate_entries
-            {
-                name: $BitFlags,
-                attrs: [$(#[$attr])*],
-            },
-            [];
-            $($vals)*
-        }
-    };
-
-    // (pub) Entry rule.
+    // Entry rule.
     (
         $(#[$attr:meta])*
-        pub enum $BitFlags:ident {
+        $v:vis enum $BitFlags:ident {
             $($vals:tt)*
         }
     ) => {
         libc_enum! {
             @accumulate_entries
             {
-                pub,
+                $v
                 name: $BitFlags,
                 attrs: [$(#[$attr])*],
             },
diff --git a/src/sys/signal.rs b/src/sys/signal.rs
index 41a62e6a..1224888e 100644
--- a/src/sys/signal.rs
+++ b/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 {
@@ -414,7 +415,7 @@ impl SigSet {
         let res = unsafe { libc::sigwait(&self.sigset as *const libc::sigset_t, signum.as_mut_ptr()) };
 
         Errno::result(res).map(|_| unsafe {
-            Signal::from_c_int(signum.assume_init()).unwrap()
+            Signal::try_from(signum.assume_init()).unwrap()
         })
     }
 }
@@ -542,6 +543,7 @@ 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! {
@@ -549,7 +551,7 @@ pub unsafe fn sigaction(signal: Signal, sigaction: &SigAction) -> Result<SigActi
 /// }
 ///
 /// 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);
 /// }
 ///
diff --git a/src/sys/wait.rs b/src/sys/wait.rs
index 7b749990..d18c3757 100644
--- a/src/sys/wait.rs
+++ b/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"))]
diff --git a/test/sys/test_signal.rs b/test/sys/test_signal.rs
index 8780763f..11875750 100644
--- a/test/sys/test_signal.rs
+++ b/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);
 }
 
diff --git a/test/sys/test_signalfd.rs b/test/sys/test_signalfd.rs
index a3b60988..92759a48 100644
--- a/test/sys/test_signalfd.rs
+++ b/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);
 }