src/libstd/sys/windows/thread.rs

   1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use alloc::boxed::FnBox;
  12 use io;
  13 use ffi::CStr;
  14 use mem;
  15 use libc::c_void;
  16 use ptr;
  17 use sys::c;
  18 use sys::handle::Handle;
  19 use sys_common::thread::*;
  20 use time::Duration;
  21
  22 pub struct Thread {
  23     handle: Handle
  24 }
  25
  26 impl Thread {
  27     pub unsafe fn new<'a>(stack: usize, p: Box<FnBox() + 'a>)
  28                           -> io::Result<Thread> {
  29         let p = box p;
  30
  31         // FIXME On UNIX, we guard against stack sizes that are too small but
  32         // that's because pthreads enforces that stacks are at least
  33         // PTHREAD_STACK_MIN bytes big.  Windows has no such lower limit, it's
  34         // just that below a certain threshold you can't do anything useful.
  35         // That threshold is application and architecture-specific, however.
  36         // Round up to the next 64 kB because that's what the NT kernel does,
  37         // might as well make it explicit.
  38         let stack_size = (stack + 0xfffe) & (!0xfffe);
  39         let ret = c::CreateThread(ptr::null_mut(), stack_size,
  40                                   thread_start, &*p as *const _ as *mut _,
  41                                   0, ptr::null_mut());
  42
  43         return if ret as usize == 0 {
  44             Err(io::Error::last_os_error())
  45         } else {
  46             mem::forget(p); // ownership passed to CreateThread
  47             Ok(Thread { handle: Handle::new(ret) })
  48         };
  49
  50         extern "system" fn thread_start(main: *mut c_void) -> c::DWORD {
  51             unsafe { start_thread(main); }
  52             0
  53         }
  54     }
  55
  56     pub fn set_name(_name: &CStr) {
  57         // Windows threads are nameless
  58         // The names in MSVC debugger are obtained using a "magic" exception,
  59         // which requires a use of MS C++ extensions.
  60         // See https://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx
  61     }
  62
  63     pub fn join(self) {
  64         unsafe { c::WaitForSingleObject(self.handle.raw(), c::INFINITE); }
  65     }
  66
  67     pub fn yield_now() {
  68         // This function will return 0 if there are no other threads to execute,
  69         // but this also means that the yield was useless so this isn't really a
  70         // case that needs to be worried about.
  71         unsafe { c::SwitchToThread(); }
  72     }
  73
  74     pub fn sleep(dur: Duration) {
  75         unsafe {
  76             c::Sleep(super::dur2timeout(dur))
  77         }
  78     }
  79
  80     pub fn handle(&self) -> &Handle { &self.handle }
  81
  82     pub fn into_handle(self) -> Handle { self.handle }
  83 }
  84
  85 #[cfg_attr(test, allow(dead_code))]
  86 pub mod guard {
  87     pub unsafe fn current() -> Option<usize> { None }
  88     pub unsafe fn init() -> Option<usize> { None }
  89 }