sync: Move underneath libstd

This commit is the final step in the libstd facade, #13851. The purpose of this
commit is to move libsync underneath the standard library, behind the facade.
This will allow core primitives like channels, queues, and atomics to all live
in the same location.

There were a few notable changes and a few breaking changes as part of this
movement:

* The `Vec` and `String` types are reexported at the top level of libcollections
* The `unreachable!()` macro was copied to libcore
* The `std::rt::thread` module was moved to librustrt, but it is still
  reexported at the same location.
* The `std::comm` module was moved to libsync
* The `sync::comm` module was moved under `sync::comm`, and renamed to `duplex`.
  It is now a private module with types/functions being reexported under
  `sync::comm`. This is a breaking change for any existing users of duplex
  streams.
* All concurrent queues/deques were moved directly under libsync. They are also
  all marked with #![experimental] for now if they are public.
* The `task_pool` and `future` modules no longer live in libsync, but rather
  live under `std::sync`. They will forever live at this location, but they may
  move to libsync if the `std::task` module moves as well.

[breaking-change]

2 files changed, 1 insertions, 352 deletions

diff --git a/src/libstd/rt/mod.rs b/src/libstd/rt/mod.rs
index a68a632bc37..66e7059422b 100644
--- a/src/libstd/rt/mod.rs
+++ b/src/libstd/rt/mod.rs
@@ -63,13 +63,10 @@ pub use self::util::{default_sched_threads, min_stack, running_on_valgrind};
 // Reexport functionality from librustrt and other crates underneath the
 // standard library which work together to create the entire runtime.
 pub use alloc::{heap, libc_heap};
-pub use rustrt::{task, local, mutex, exclusive, stack, args, rtio};
+pub use rustrt::{task, local, mutex, exclusive, stack, args, rtio, thread};
 pub use rustrt::{Stdio, Stdout, Stderr, begin_unwind, begin_unwind_fmt};
 pub use rustrt::{bookkeeping, at_exit, unwind, DEFAULT_ERROR_CODE, Runtime};
 
-// Bindings to system threading libraries.
-pub mod thread;
-
 // Simple backtrace functionality (to print on failure)
 pub mod backtrace;
 
diff --git a/src/libstd/rt/thread.rs b/src/libstd/rt/thread.rs
deleted file mode 100644
index 5a077e511c0..00000000000
--- a/src/libstd/rt/thread.rs
+++ /dev/null
@@ -1,348 +0,0 @@
-// Copyright 2013-2014 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.
-
-//! Native os-thread management
-//!
-//! This modules contains bindings necessary for managing OS-level threads.
-//! These functions operate outside of the rust runtime, creating threads
-//! which are not used for scheduling in any way.
-
-#![allow(non_camel_case_types)]
-#![allow(unsigned_negate)]
-
-use kinds::Send;
-use libc;
-use mem;
-use ops::Drop;
-use option::{Option, Some, None};
-use owned::Box;
-use uint;
-
-type StartFn = extern "C" fn(*libc::c_void) -> imp::rust_thread_return;
-
-/// This struct represents a native thread's state. This is used to join on an
-/// existing thread created in the join-able state.
-pub struct Thread<T> {
-    native: imp::rust_thread,
-    joined: bool,
-    packet: Box<Option<T>>,
-}
-
-static DEFAULT_STACK_SIZE: uint = 1024 * 1024;
-
-// This is the starting point of rust os threads. The first thing we do
-// is make sure that we don't trigger __morestack (also why this has a
-// no_split_stack annotation), and then we extract the main function
-// and invoke it.
-#[no_split_stack]
-extern fn thread_start(main: *libc::c_void) -> imp::rust_thread_return {
-    use rt::stack;
-    unsafe {
-        stack::record_stack_bounds(0, uint::MAX);
-        let f: Box<proc()> = mem::transmute(main);
-        (*f)();
-        mem::transmute(0 as imp::rust_thread_return)
-    }
-}
-
-// There are two impl blocks b/c if T were specified at the top then it's just a
-// pain to specify a type parameter on Thread::spawn (which doesn't need the
-// type parameter).
-impl Thread<()> {
-
-    /// Starts execution of a new OS thread.
-    ///
-    /// This function will not wait for the thread to join, but a handle to the
-    /// thread will be returned.
-    ///
-    /// Note that the handle returned is used to acquire the return value of the
-    /// procedure `main`. The `join` function will wait for the thread to finish
-    /// and return the value that `main` generated.
-    ///
-    /// Also note that the `Thread` returned will *always* wait for the thread
-    /// to finish executing. This means that even if `join` is not explicitly
-    /// called, when the `Thread` falls out of scope its destructor will block
-    /// waiting for the OS thread.
-    pub fn start<T: Send>(main: proc():Send -> T) -> Thread<T> {
-        Thread::start_stack(DEFAULT_STACK_SIZE, main)
-    }
-
-    /// Performs the same functionality as `start`, but specifies an explicit
-    /// stack size for the new thread.
-    pub fn start_stack<T: Send>(stack: uint, main: proc():Send -> T) -> Thread<T> {
-
-        // We need the address of the packet to fill in to be stable so when
-        // `main` fills it in it's still valid, so allocate an extra box to do
-        // so.
-        let packet = box None;
-        let packet2: *mut Option<T> = unsafe {
-            *mem::transmute::<&Box<Option<T>>, **mut Option<T>>(&packet)
-        };
-        let main = proc() unsafe { *packet2 = Some(main()); };
-        let native = unsafe { imp::create(stack, box main) };
-
-        Thread {
-            native: native,
-            joined: false,
-            packet: packet,
-        }
-    }
-
-    /// This will spawn a new thread, but it will not wait for the thread to
-    /// finish, nor is it possible to wait for the thread to finish.
-    ///
-    /// This corresponds to creating threads in the 'detached' state on unix
-    /// systems. Note that platforms may not keep the main program alive even if
-    /// there are detached thread still running around.
-    pub fn spawn(main: proc():Send) {
-        Thread::spawn_stack(DEFAULT_STACK_SIZE, main)
-    }
-
-    /// Performs the same functionality as `spawn`, but explicitly specifies a
-    /// stack size for the new thread.
-    pub fn spawn_stack(stack: uint, main: proc():Send) {
-        unsafe {
-            let handle = imp::create(stack, box main);
-            imp::detach(handle);
-        }
-    }
-
-    /// Relinquishes the CPU slot that this OS-thread is currently using,
-    /// allowing another thread to run for awhile.
-    pub fn yield_now() {
-        unsafe { imp::yield_now(); }
-    }
-}
-
-impl<T: Send> Thread<T> {
-    /// Wait for this thread to finish, returning the result of the thread's
-    /// calculation.
-    pub fn join(mut self) -> T {
-        assert!(!self.joined);
-        unsafe { imp::join(self.native) };
-        self.joined = true;
-        assert!(self.packet.is_some());
-        self.packet.take_unwrap()
-    }
-}
-
-#[unsafe_destructor]
-impl<T: Send> Drop for Thread<T> {
-    fn drop(&mut self) {
-        // This is required for correctness. If this is not done then the thread
-        // would fill in a return box which no longer exists.
-        if !self.joined {
-            unsafe { imp::join(self.native) };
-        }
-    }
-}
-
-#[cfg(windows)]
-mod imp {
-    use mem;
-    use cmp;
-    use kinds::Send;
-    use libc;
-    use libc::types::os::arch::extra::{LPSECURITY_ATTRIBUTES, SIZE_T, BOOL,
-                                       LPVOID, DWORD, LPDWORD, HANDLE};
-    use os;
-    use owned::Box;
-    use ptr;
-    use rt::stack::RED_ZONE;
-
-    pub type rust_thread = HANDLE;
-    pub type rust_thread_return = DWORD;
-
-    pub unsafe fn create(stack: uint, p: Box<proc():Send>) -> rust_thread {
-        let arg: *mut libc::c_void = mem::transmute(p);
-        // FIXME On UNIX, we guard against stack sizes that are too small but
-        // that's because pthreads enforces that stacks are at least
-        // PTHREAD_STACK_MIN bytes big.  Windows has no such lower limit, it's
-        // just that below a certain threshold you can't do anything useful.
-        // That threshold is application and architecture-specific, however.
-        // For now, the only requirement is that it's big enough to hold the
-        // red zone.  Round up to the next 64 kB because that's what the NT
-        // kernel does, might as well make it explicit.  With the current
-        // 20 kB red zone, that makes for a 64 kB minimum stack.
-        let stack_size = (cmp::max(stack, RED_ZONE) + 0xfffe) & (-0xfffe - 1);
-        let ret = CreateThread(ptr::mut_null(), stack_size as libc::size_t,
-                               super::thread_start, arg, 0, ptr::mut_null());
-
-        if ret as uint == 0 {
-            // be sure to not leak the closure
-            let _p: Box<proc():Send> = mem::transmute(arg);
-            fail!("failed to spawn native thread: {}", os::last_os_error());
-        }
-        return ret;
-    }
-
-    pub unsafe fn join(native: rust_thread) {
-        use libc::consts::os::extra::INFINITE;
-        WaitForSingleObject(native, INFINITE);
-    }
-
-    pub unsafe fn detach(native: rust_thread) {
-        assert!(libc::CloseHandle(native) != 0);
-    }
-
-    pub unsafe fn yield_now() {
-        // This function will return 0 if there are no other threads to execute,
-        // but this also means that the yield was useless so this isn't really a
-        // case that needs to be worried about.
-        SwitchToThread();
-    }
-
-    #[allow(non_snake_case_functions)]
-    extern "system" {
-        fn CreateThread(lpThreadAttributes: LPSECURITY_ATTRIBUTES,
-                        dwStackSize: SIZE_T,
-                        lpStartAddress: super::StartFn,
-                        lpParameter: LPVOID,
-                        dwCreationFlags: DWORD,
-                        lpThreadId: LPDWORD) -> HANDLE;
-        fn WaitForSingleObject(hHandle: HANDLE, dwMilliseconds: DWORD) -> DWORD;
-        fn SwitchToThread() -> BOOL;
-    }
-}
-
-#[cfg(unix)]
-mod imp {
-    use cmp;
-    use kinds::Send;
-    use libc::consts::os::posix01::{PTHREAD_CREATE_JOINABLE, PTHREAD_STACK_MIN};
-    use libc;
-    use mem;
-    use os;
-    use owned::Box;
-    use ptr;
-    use rt::stack::RED_ZONE;
-
-    pub type rust_thread = libc::pthread_t;
-    pub type rust_thread_return = *u8;
-
-    pub unsafe fn create(stack: uint, p: Box<proc():Send>) -> rust_thread {
-        let mut native: libc::pthread_t = mem::zeroed();
-        let mut attr: libc::pthread_attr_t = mem::zeroed();
-        assert_eq!(pthread_attr_init(&mut attr), 0);
-        assert_eq!(pthread_attr_setdetachstate(&mut attr,
-                                               PTHREAD_CREATE_JOINABLE), 0);
-
-        // Reserve room for the red zone, the runtime's stack of last resort.
-        let stack_size = cmp::max(stack, RED_ZONE + min_stack_size(&attr) as uint);
-        match pthread_attr_setstacksize(&mut attr, stack_size as libc::size_t) {
-            0 => {
-            },
-            libc::EINVAL => {
-                // EINVAL means |stack_size| is either too small or not a
-                // multiple of the system page size.  Because it's definitely
-                // >= PTHREAD_STACK_MIN, it must be an alignment issue.
-                // Round up to the nearest page and try again.
-                let page_size = os::page_size();
-                let stack_size = (stack_size + page_size - 1) & (-(page_size - 1) - 1);
-                assert_eq!(pthread_attr_setstacksize(&mut attr, stack_size as libc::size_t), 0);
-            },
-            errno => {
-                // This cannot really happen.
-                fail!("pthread_attr_setstacksize() error: {} ({})", os::last_os_error(), errno);
-            },
-        };
-
-        let arg: *libc::c_void = mem::transmute(p);
-        let ret = pthread_create(&mut native, &attr, super::thread_start, arg);
-        assert_eq!(pthread_attr_destroy(&mut attr), 0);
-
-        if ret != 0 {
-            // be sure to not leak the closure
-            let _p: Box<proc():Send> = mem::transmute(arg);
-            fail!("failed to spawn native thread: {}", os::last_os_error());
-        }
-        native
-    }
-
-    pub unsafe fn join(native: rust_thread) {
-        assert_eq!(pthread_join(native, ptr::null()), 0);
-    }
-
-    pub unsafe fn detach(native: rust_thread) {
-        assert_eq!(pthread_detach(native), 0);
-    }
-
-    pub unsafe fn yield_now() { assert_eq!(sched_yield(), 0); }
-
-    // glibc >= 2.15 has a __pthread_get_minstack() function that returns
-    // PTHREAD_STACK_MIN plus however many bytes are needed for thread-local
-    // storage.  We need that information to avoid blowing up when a small stack
-    // is created in an application with big thread-local storage requirements.
-    // See #6233 for rationale and details.
-    //
-    // Link weakly to the symbol for compatibility with older versions of glibc.
-    // Assumes that we've been dynamically linked to libpthread but that is
-    // currently always the case.  Note that you need to check that the symbol
-    // is non-null before calling it!
-    #[cfg(target_os = "linux")]
-    fn min_stack_size(attr: *libc::pthread_attr_t) -> libc::size_t {
-        use ptr::RawPtr;
-        type F = unsafe extern "C" fn(*libc::pthread_attr_t) -> libc::size_t;
-        extern {
-            #[linkage = "extern_weak"]
-            static __pthread_get_minstack: *();
-        }
-        if __pthread_get_minstack.is_null() {
-            PTHREAD_STACK_MIN
-        } else {
-            unsafe { mem::transmute::<*(), F>(__pthread_get_minstack)(attr) }
-        }
-    }
-
-    // __pthread_get_minstack() is marked as weak but extern_weak linkage is
-    // not supported on OS X, hence this kludge...
-    #[cfg(not(target_os = "linux"))]
-    fn min_stack_size(_: *libc::pthread_attr_t) -> libc::size_t {
-        PTHREAD_STACK_MIN
-    }
-
-    extern {
-        fn pthread_create(native: *mut libc::pthread_t,
-                          attr: *libc::pthread_attr_t,
-                          f: super::StartFn,
-                          value: *libc::c_void) -> libc::c_int;
-        fn pthread_join(native: libc::pthread_t,
-                        value: **libc::c_void) -> libc::c_int;
-        fn pthread_attr_init(attr: *mut libc::pthread_attr_t) -> libc::c_int;
-        fn pthread_attr_destroy(attr: *mut libc::pthread_attr_t) -> libc::c_int;
-        fn pthread_attr_setstacksize(attr: *mut libc::pthread_attr_t,
-                                     stack_size: libc::size_t) -> libc::c_int;
-        fn pthread_attr_setdetachstate(attr: *mut libc::pthread_attr_t,
-                                       state: libc::c_int) -> libc::c_int;
-        fn pthread_detach(thread: libc::pthread_t) -> libc::c_int;
-        fn sched_yield() -> libc::c_int;
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::Thread;
-
-    #[test]
-    fn smoke() { Thread::start(proc (){}).join(); }
-
-    #[test]
-    fn data() { assert_eq!(Thread::start(proc () { 1 }).join(), 1); }
-
-    #[test]
-    fn detached() { Thread::spawn(proc () {}) }
-
-    #[test]
-    fn small_stacks() {
-        assert_eq!(42, Thread::start_stack(0, proc () 42).join());
-        assert_eq!(42, Thread::start_stack(1, proc () 42).join());
-    }
-}
-