std: Second pass stabilization of sync

This pass performs a second pass of stabilization through the `std::sync`
module, avoiding modules/types that are being handled in other PRs (e.g.
mutexes, rwlocks, condvars, and channels).

The following items are now stable

* `sync::atomic`
* `sync::atomic::ATOMIC_BOOL_INIT` (was `INIT_ATOMIC_BOOL`)
* `sync::atomic::ATOMIC_INT_INIT` (was `INIT_ATOMIC_INT`)
* `sync::atomic::ATOMIC_UINT_INIT` (was `INIT_ATOMIC_UINT`)
* `sync::Once`
* `sync::ONCE_INIT`
* `sync::Once::call_once` (was `doit`)
  * C == `pthread_once(..)`
  * Boost == `call_once(..)`
  * Windows == `InitOnceExecuteOnce`
* `sync::Barrier`
* `sync::Barrier::new`
* `sync::Barrier::wait` (now returns a `bool`)
* `sync::Semaphore::new`
* `sync::Semaphore::acquire`
* `sync::Semaphore::release`

The following items remain unstable

* `sync::SemaphoreGuard`
* `sync::Semaphore::access` - it's unclear how this relates to the poisoning
                              story of mutexes.
* `sync::TaskPool` - the semantics of a failing task and whether a thread is
                     re-attached to a thread pool are somewhat unclear, and the
                     utility of this type in `sync` is question with respect to
                     the jobs of other primitives. This type will likely become
                     stable or move out of the standard library over time.
* `sync::Future` - futures as-is have yet to be deeply re-evaluated with the
                   recent core changes to Rust's synchronization story, and will
                   likely become stable in the future but are unstable until
                   that time comes.

[breaking-change]

6 files changed, 8 insertions, 12 deletions

diff --git a/src/libstd/sys/common/thread_local.rs b/src/libstd/sys/common/thread_local.rs
index fe7a7d8d037..597790af83c 100644
--- a/src/libstd/sys/common/thread_local.rs
+++ b/src/libstd/sys/common/thread_local.rs
@@ -137,7 +137,7 @@ pub const INIT: StaticKey = StaticKey {
 ///
 /// This value allows specific configuration of the destructor for a TLS key.
 pub const INIT_INNER: StaticKeyInner = StaticKeyInner {
-    key: atomic::INIT_ATOMIC_UINT,
+    key: atomic::ATOMIC_UINT_INIT,
 };
 
 static INIT_KEYS: Once = ONCE_INIT;
diff --git a/src/libstd/sys/unix/os.rs b/src/libstd/sys/unix/os.rs
index 595191db3b2..0ccf130af6e 100644
--- a/src/libstd/sys/unix/os.rs
+++ b/src/libstd/sys/unix/os.rs
@@ -18,7 +18,7 @@ use io::{IoError, IoResult};
 use libc::{mod, c_int, c_char, c_void};
 use path::BytesContainer;
 use ptr;
-use sync::atomic::{AtomicInt, INIT_ATOMIC_INT, SeqCst};
+use sync::atomic::{AtomicInt, SeqCst};
 use sys::fs::FileDesc;
 use os;
 
diff --git a/src/libstd/sys/unix/pipe.rs b/src/libstd/sys/unix/pipe.rs
index 868b460aa5e..1e1b95ee96c 100644
--- a/src/libstd/sys/unix/pipe.rs
+++ b/src/libstd/sys/unix/pipe.rs
@@ -8,13 +8,14 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use prelude::*;
+
 use alloc::arc::Arc;
 use libc;
 use c_str::CString;
 use mem;
 use sync::{atomic, Mutex};
 use io::{mod, IoResult, IoError};
-use prelude::*;
 
 use sys::{mod, timer, retry, c, set_nonblocking, wouldblock};
 use sys::fs::{fd_t, FileDesc};
@@ -117,9 +118,6 @@ pub struct UnixStream {
     write_deadline: u64,
 }
 
-unsafe impl Send for UnixStream {}
-unsafe impl Sync for UnixStream {}
-
 impl UnixStream {
     pub fn connect(addr: &CString,
                    timeout: Option<u64>) -> IoResult<UnixStream> {
@@ -218,6 +216,7 @@ pub struct UnixListener {
     path: CString,
 }
 
+// we currently own the CString, so these impls should be safe
 unsafe impl Send for UnixListener {}
 unsafe impl Sync for UnixListener {}
 
@@ -265,9 +264,6 @@ struct AcceptorInner {
     closed: atomic::AtomicBool,
 }
 
-unsafe impl Send for AcceptorInner {}
-unsafe impl Sync for AcceptorInner {}
-
 impl UnixAcceptor {
     pub fn fd(&self) -> fd_t { self.inner.listener.fd() }
 
diff --git a/src/libstd/sys/unix/timer.rs b/src/libstd/sys/unix/timer.rs
index c0ef89666c0..25216c35b65 100644
--- a/src/libstd/sys/unix/timer.rs
+++ b/src/libstd/sys/unix/timer.rs
@@ -211,7 +211,7 @@ impl Timer {
         // instead of ()
         HELPER.boot(|| {}, helper);
 
-        static ID: atomic::AtomicUint = atomic::INIT_ATOMIC_UINT;
+        static ID: atomic::AtomicUint = atomic::ATOMIC_UINT_INIT;
         let id = ID.fetch_add(1, atomic::Relaxed);
         Ok(Timer {
             id: id,
diff --git a/src/libstd/sys/windows/mod.rs b/src/libstd/sys/windows/mod.rs
index 57c284ed6a3..88313d66173 100644
--- a/src/libstd/sys/windows/mod.rs
+++ b/src/libstd/sys/windows/mod.rs
@@ -171,7 +171,7 @@ pub fn init_net() {
     unsafe {
         static START: Once = ONCE_INIT;
 
-        START.doit(|| {
+        START.call_once(|| {
             let mut data: c::WSADATA = mem::zeroed();
             let ret = c::WSAStartup(0x202, // version 2.2
                                     &mut data);
diff --git a/src/libstd/sys/windows/mutex.rs b/src/libstd/sys/windows/mutex.rs
index 3ac7c09154e..5f65b429d86 100644
--- a/src/libstd/sys/windows/mutex.rs
+++ b/src/libstd/sys/windows/mutex.rs
@@ -20,7 +20,7 @@ const SPIN_COUNT: DWORD = 4000;
 
 pub struct Mutex { inner: atomic::AtomicUint }
 
-pub const MUTEX_INIT: Mutex = Mutex { inner: atomic::INIT_ATOMIC_UINT };
+pub const MUTEX_INIT: Mutex = Mutex { inner: atomic::ATOMIC_UINT_INIT };
 
 unsafe impl Sync for Mutex {}