7828c3dd28
https://github.com/rust-lang/rfcs/pull/221 The current terminology of "task failure" often causes problems when writing or speaking about code. You often want to talk about the possibility of an operation that returns a Result "failing", but cannot because of the ambiguity with task failure. Instead, you have to speak of "the failing case" or "when the operation does not succeed" or other circumlocutions. Likewise, we use a "Failure" header in rustdoc to describe when operations may fail the task, but it would often be helpful to separate out a section describing the "Err-producing" case. We have been steadily moving away from task failure and toward Result as an error-handling mechanism, so we should optimize our terminology accordingly: Result-producing functions should be easy to describe. To update your code, rename any call to `fail!` to `panic!` instead. Assuming you have not created your own macro named `panic!`, this will work on UNIX based systems: grep -lZR 'fail!' . | xargs -0 -l sed -i -e 's/fail!/panic!/g' You can of course also do this by hand. [breaking-change]
548 lines
19 KiB
Rust
548 lines
19 KiB
Rust
// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! Native os-thread management
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//!
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//! This modules contains bindings necessary for managing OS-level threads.
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//! These functions operate outside of the rust runtime, creating threads
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//! which are not used for scheduling in any way.
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#![allow(non_camel_case_types)]
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use core::prelude::*;
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use alloc::boxed::Box;
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use core::mem;
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use core::uint;
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use libc;
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use stack;
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use stack_overflow;
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pub unsafe fn init() {
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imp::guard::init();
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stack_overflow::init();
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}
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pub unsafe fn cleanup() {
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stack_overflow::cleanup();
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}
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#[cfg(target_os = "windows")]
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type StartFn = extern "system" fn(*mut libc::c_void) -> imp::rust_thread_return;
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#[cfg(not(target_os = "windows"))]
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type StartFn = extern "C" fn(*mut libc::c_void) -> imp::rust_thread_return;
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/// This struct represents a native thread's state. This is used to join on an
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/// existing thread created in the join-able state.
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pub struct Thread<T> {
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native: imp::rust_thread,
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joined: bool,
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packet: Box<Option<T>>,
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}
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static DEFAULT_STACK_SIZE: uint = 1024 * 1024;
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// This is the starting point of rust os threads. The first thing we do
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// is make sure that we don't trigger __morestack (also why this has a
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// no_stack_check annotation), and then we extract the main function
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// and invoke it.
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#[no_stack_check]
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fn start_thread(main: *mut libc::c_void) -> imp::rust_thread_return {
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unsafe {
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stack::record_os_managed_stack_bounds(0, uint::MAX);
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let handler = stack_overflow::Handler::new();
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let f: Box<proc()> = mem::transmute(main);
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(*f)();
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drop(handler);
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mem::transmute(0 as imp::rust_thread_return)
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}
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}
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#[no_stack_check]
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#[cfg(target_os = "windows")]
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extern "system" fn thread_start(main: *mut libc::c_void) -> imp::rust_thread_return {
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return start_thread(main);
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}
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#[no_stack_check]
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#[cfg(not(target_os = "windows"))]
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extern fn thread_start(main: *mut libc::c_void) -> imp::rust_thread_return {
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return start_thread(main);
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}
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/// Returns the last writable byte of the main thread's stack next to the guard
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/// page. Must be called from the main thread.
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pub fn main_guard_page() -> uint {
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unsafe {
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imp::guard::main()
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}
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}
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/// Returns the last writable byte of the current thread's stack next to the
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/// guard page. Must not be called from the main thread.
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pub fn current_guard_page() -> uint {
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unsafe {
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imp::guard::current()
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}
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}
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// There are two impl blocks b/c if T were specified at the top then it's just a
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// pain to specify a type parameter on Thread::spawn (which doesn't need the
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// type parameter).
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impl Thread<()> {
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/// Starts execution of a new OS thread.
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///
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/// This function will not wait for the thread to join, but a handle to the
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/// thread will be returned.
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///
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/// Note that the handle returned is used to acquire the return value of the
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/// procedure `main`. The `join` function will wait for the thread to finish
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/// and return the value that `main` generated.
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///
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/// Also note that the `Thread` returned will *always* wait for the thread
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/// to finish executing. This means that even if `join` is not explicitly
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/// called, when the `Thread` falls out of scope its destructor will block
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/// waiting for the OS thread.
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pub fn start<T: Send>(main: proc():Send -> T) -> Thread<T> {
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Thread::start_stack(DEFAULT_STACK_SIZE, main)
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}
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/// Performs the same functionality as `start`, but specifies an explicit
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/// stack size for the new thread.
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pub fn start_stack<T: Send>(stack: uint, main: proc():Send -> T) -> Thread<T> {
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// We need the address of the packet to fill in to be stable so when
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// `main` fills it in it's still valid, so allocate an extra box to do
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// so.
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let packet = box None;
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let packet2: *mut Option<T> = unsafe {
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*mem::transmute::<&Box<Option<T>>, *const *mut Option<T>>(&packet)
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};
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let main = proc() unsafe { *packet2 = Some(main()); };
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let native = unsafe { imp::create(stack, box main) };
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Thread {
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native: native,
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joined: false,
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packet: packet,
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}
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}
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/// This will spawn a new thread, but it will not wait for the thread to
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/// finish, nor is it possible to wait for the thread to finish.
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///
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/// This corresponds to creating threads in the 'detached' state on unix
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/// systems. Note that platforms may not keep the main program alive even if
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/// there are detached thread still running around.
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pub fn spawn(main: proc():Send) {
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Thread::spawn_stack(DEFAULT_STACK_SIZE, main)
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}
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/// Performs the same functionality as `spawn`, but explicitly specifies a
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/// stack size for the new thread.
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pub fn spawn_stack(stack: uint, main: proc():Send) {
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unsafe {
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let handle = imp::create(stack, box main);
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imp::detach(handle);
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}
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}
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/// Relinquishes the CPU slot that this OS-thread is currently using,
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/// allowing another thread to run for awhile.
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pub fn yield_now() {
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unsafe { imp::yield_now(); }
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}
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}
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impl<T: Send> Thread<T> {
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/// Wait for this thread to finish, returning the result of the thread's
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/// calculation.
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pub fn join(mut self) -> T {
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assert!(!self.joined);
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unsafe { imp::join(self.native) };
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self.joined = true;
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assert!(self.packet.is_some());
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self.packet.take().unwrap()
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}
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}
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#[unsafe_destructor]
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impl<T: Send> Drop for Thread<T> {
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fn drop(&mut self) {
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// This is required for correctness. If this is not done then the thread
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// would fill in a return box which no longer exists.
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if !self.joined {
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unsafe { imp::join(self.native) };
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}
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}
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}
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#[cfg(windows)]
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#[allow(non_snake_case)]
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mod imp {
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use core::prelude::*;
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use alloc::boxed::Box;
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use core::cmp;
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use core::mem;
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use core::ptr;
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use libc;
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use libc::types::os::arch::extra::{LPSECURITY_ATTRIBUTES, SIZE_T, BOOL,
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LPVOID, DWORD, LPDWORD, HANDLE};
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use stack::RED_ZONE;
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pub type rust_thread = HANDLE;
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pub type rust_thread_return = DWORD;
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pub mod guard {
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pub unsafe fn main() -> uint {
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0
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}
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pub unsafe fn current() -> uint {
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0
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}
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pub unsafe fn init() {
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}
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}
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pub unsafe fn create(stack: uint, p: Box<proc():Send>) -> rust_thread {
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let arg: *mut libc::c_void = mem::transmute(p);
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// FIXME On UNIX, we guard against stack sizes that are too small but
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// that's because pthreads enforces that stacks are at least
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// PTHREAD_STACK_MIN bytes big. Windows has no such lower limit, it's
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// just that below a certain threshold you can't do anything useful.
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// That threshold is application and architecture-specific, however.
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// For now, the only requirement is that it's big enough to hold the
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// red zone. Round up to the next 64 kB because that's what the NT
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// kernel does, might as well make it explicit. With the current
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// 20 kB red zone, that makes for a 64 kB minimum stack.
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let stack_size = (cmp::max(stack, RED_ZONE) + 0xfffe) & (-0xfffe - 1);
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let ret = CreateThread(ptr::null_mut(), stack_size as libc::size_t,
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super::thread_start, arg, 0, ptr::null_mut());
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if ret as uint == 0 {
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// be sure to not leak the closure
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let _p: Box<proc():Send> = mem::transmute(arg);
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panic!("failed to spawn native thread: {}", ret);
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}
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return ret;
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}
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pub unsafe fn join(native: rust_thread) {
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use libc::consts::os::extra::INFINITE;
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WaitForSingleObject(native, INFINITE);
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}
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pub unsafe fn detach(native: rust_thread) {
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assert!(libc::CloseHandle(native) != 0);
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}
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pub unsafe fn yield_now() {
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// This function will return 0 if there are no other threads to execute,
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// but this also means that the yield was useless so this isn't really a
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// case that needs to be worried about.
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SwitchToThread();
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}
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#[allow(non_snake_case)]
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extern "system" {
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fn CreateThread(lpThreadAttributes: LPSECURITY_ATTRIBUTES,
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dwStackSize: SIZE_T,
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lpStartAddress: super::StartFn,
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lpParameter: LPVOID,
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dwCreationFlags: DWORD,
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lpThreadId: LPDWORD) -> HANDLE;
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fn WaitForSingleObject(hHandle: HANDLE, dwMilliseconds: DWORD) -> DWORD;
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fn SwitchToThread() -> BOOL;
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}
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}
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#[cfg(unix)]
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mod imp {
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use core::prelude::*;
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use alloc::boxed::Box;
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use core::cmp;
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use core::mem;
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use core::ptr;
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use libc::consts::os::posix01::{PTHREAD_CREATE_JOINABLE, PTHREAD_STACK_MIN};
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use libc;
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use stack::RED_ZONE;
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pub type rust_thread = libc::pthread_t;
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pub type rust_thread_return = *mut u8;
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#[cfg(all(not(target_os = "linux"), not(target_os = "macos")))]
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pub mod guard {
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pub unsafe fn current() -> uint {
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0
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}
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pub unsafe fn main() -> uint {
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0
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}
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pub unsafe fn init() {
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}
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}
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#[cfg(any(target_os = "linux", target_os = "macos"))]
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pub mod guard {
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use super::*;
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#[cfg(any(target_os = "linux", target_os = "android"))]
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use core::mem;
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#[cfg(any(target_os = "linux", target_os = "android"))]
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use core::ptr;
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use libc;
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use libc::funcs::posix88::mman::{mmap};
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use libc::consts::os::posix88::{PROT_NONE,
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MAP_PRIVATE,
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MAP_ANON,
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MAP_FAILED,
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MAP_FIXED};
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// These are initialized in init() and only read from after
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static mut PAGE_SIZE: uint = 0;
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static mut GUARD_PAGE: uint = 0;
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#[cfg(target_os = "macos")]
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unsafe fn get_stack_start() -> *mut libc::c_void {
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current() as *mut libc::c_void
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}
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#[cfg(any(target_os = "linux", target_os = "android"))]
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unsafe fn get_stack_start() -> *mut libc::c_void {
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let mut attr: libc::pthread_attr_t = mem::zeroed();
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if pthread_getattr_np(pthread_self(), &mut attr) != 0 {
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panic!("failed to get thread attributes");
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}
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let mut stackaddr = ptr::null_mut();
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let mut stacksize = 0;
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if pthread_attr_getstack(&attr, &mut stackaddr, &mut stacksize) != 0 {
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panic!("failed to get stack information");
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}
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if pthread_attr_destroy(&mut attr) != 0 {
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panic!("failed to destroy thread attributes");
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}
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stackaddr
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}
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pub unsafe fn init() {
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let psize = libc::sysconf(libc::consts::os::sysconf::_SC_PAGESIZE);
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if psize == -1 {
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panic!("failed to get page size");
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}
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PAGE_SIZE = psize as uint;
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let stackaddr = get_stack_start();
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// Rellocate the last page of the stack.
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// This ensures SIGBUS will be raised on
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// stack overflow.
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let result = mmap(stackaddr,
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PAGE_SIZE as libc::size_t,
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PROT_NONE,
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MAP_PRIVATE | MAP_ANON | MAP_FIXED,
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-1,
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0);
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if result != stackaddr || result == MAP_FAILED {
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panic!("failed to allocate a guard page");
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}
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let offset = if cfg!(target_os = "linux") {
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2
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} else {
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1
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};
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GUARD_PAGE = stackaddr as uint + offset * PAGE_SIZE;
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}
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pub unsafe fn main() -> uint {
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GUARD_PAGE
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}
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#[cfg(target_os = "macos")]
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pub unsafe fn current() -> uint {
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(pthread_get_stackaddr_np(pthread_self()) as libc::size_t -
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pthread_get_stacksize_np(pthread_self())) as uint
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}
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#[cfg(any(target_os = "linux", target_os = "android"))]
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pub unsafe fn current() -> uint {
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let mut attr: libc::pthread_attr_t = mem::zeroed();
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if pthread_getattr_np(pthread_self(), &mut attr) != 0 {
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panic!("failed to get thread attributes");
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}
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let mut guardsize = 0;
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if pthread_attr_getguardsize(&attr, &mut guardsize) != 0 {
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panic!("failed to get stack guard page");
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}
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if guardsize == 0 {
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panic!("there is no guard page");
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}
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let mut stackaddr = ptr::null_mut();
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let mut stacksize = 0;
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if pthread_attr_getstack(&attr, &mut stackaddr, &mut stacksize) != 0 {
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panic!("failed to get stack information");
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}
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if pthread_attr_destroy(&mut attr) != 0 {
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panic!("failed to destroy thread attributes");
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}
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stackaddr as uint + guardsize as uint
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}
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}
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pub unsafe fn create(stack: uint, p: Box<proc():Send>) -> rust_thread {
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let mut native: libc::pthread_t = mem::zeroed();
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let mut attr: libc::pthread_attr_t = mem::zeroed();
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assert_eq!(pthread_attr_init(&mut attr), 0);
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assert_eq!(pthread_attr_setdetachstate(&mut attr,
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PTHREAD_CREATE_JOINABLE), 0);
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// Reserve room for the red zone, the runtime's stack of last resort.
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let stack_size = cmp::max(stack, RED_ZONE + min_stack_size(&attr) as uint);
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match pthread_attr_setstacksize(&mut attr, stack_size as libc::size_t) {
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0 => {
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},
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libc::EINVAL => {
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// EINVAL means |stack_size| is either too small or not a
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// multiple of the system page size. Because it's definitely
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// >= PTHREAD_STACK_MIN, it must be an alignment issue.
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// Round up to the nearest page and try again.
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let page_size = libc::sysconf(libc::_SC_PAGESIZE) as uint;
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let stack_size = (stack_size + page_size - 1) &
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(-(page_size as int - 1) as uint - 1);
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assert_eq!(pthread_attr_setstacksize(&mut attr, stack_size as libc::size_t), 0);
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},
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errno => {
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// This cannot really happen.
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panic!("pthread_attr_setstacksize() error: {}", errno);
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},
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};
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let arg: *mut libc::c_void = mem::transmute(p);
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let ret = pthread_create(&mut native, &attr, super::thread_start, arg);
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assert_eq!(pthread_attr_destroy(&mut attr), 0);
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if ret != 0 {
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// be sure to not leak the closure
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let _p: Box<proc():Send> = mem::transmute(arg);
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panic!("failed to spawn native thread: {}", ret);
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}
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native
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}
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pub unsafe fn join(native: rust_thread) {
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assert_eq!(pthread_join(native, ptr::null_mut()), 0);
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}
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pub unsafe fn detach(native: rust_thread) {
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assert_eq!(pthread_detach(native), 0);
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}
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pub unsafe fn yield_now() { assert_eq!(sched_yield(), 0); }
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// glibc >= 2.15 has a __pthread_get_minstack() function that returns
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// PTHREAD_STACK_MIN plus however many bytes are needed for thread-local
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// storage. We need that information to avoid blowing up when a small stack
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// is created in an application with big thread-local storage requirements.
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// See #6233 for rationale and details.
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//
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// Link weakly to the symbol for compatibility with older versions of glibc.
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// Assumes that we've been dynamically linked to libpthread but that is
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// currently always the case. Note that you need to check that the symbol
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// is non-null before calling it!
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|
#[cfg(target_os = "linux")]
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fn min_stack_size(attr: *const libc::pthread_attr_t) -> libc::size_t {
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type F = unsafe extern "C" fn(*const libc::pthread_attr_t) -> libc::size_t;
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extern {
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#[linkage = "extern_weak"]
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static __pthread_get_minstack: *const ();
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}
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if __pthread_get_minstack.is_null() {
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PTHREAD_STACK_MIN
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} else {
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unsafe { mem::transmute::<*const (), F>(__pthread_get_minstack)(attr) }
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}
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}
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// __pthread_get_minstack() is marked as weak but extern_weak linkage is
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// not supported on OS X, hence this kludge...
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#[cfg(not(target_os = "linux"))]
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fn min_stack_size(_: *const libc::pthread_attr_t) -> libc::size_t {
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PTHREAD_STACK_MIN
|
|
}
|
|
|
|
#[cfg(any(target_os = "linux"))]
|
|
extern {
|
|
pub fn pthread_self() -> libc::pthread_t;
|
|
pub fn pthread_getattr_np(native: libc::pthread_t,
|
|
attr: *mut libc::pthread_attr_t) -> libc::c_int;
|
|
pub fn pthread_attr_getguardsize(attr: *const libc::pthread_attr_t,
|
|
guardsize: *mut libc::size_t) -> libc::c_int;
|
|
pub fn pthread_attr_getstack(attr: *const libc::pthread_attr_t,
|
|
stackaddr: *mut *mut libc::c_void,
|
|
stacksize: *mut libc::size_t) -> libc::c_int;
|
|
}
|
|
|
|
#[cfg(target_os = "macos")]
|
|
extern {
|
|
pub fn pthread_self() -> libc::pthread_t;
|
|
pub fn pthread_get_stackaddr_np(thread: libc::pthread_t) -> *mut libc::c_void;
|
|
pub fn pthread_get_stacksize_np(thread: libc::pthread_t) -> libc::size_t;
|
|
}
|
|
|
|
extern {
|
|
fn pthread_create(native: *mut libc::pthread_t,
|
|
attr: *const libc::pthread_attr_t,
|
|
f: super::StartFn,
|
|
value: *mut libc::c_void) -> libc::c_int;
|
|
fn pthread_join(native: libc::pthread_t,
|
|
value: *mut *mut libc::c_void) -> libc::c_int;
|
|
fn pthread_attr_init(attr: *mut libc::pthread_attr_t) -> libc::c_int;
|
|
pub 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 () { 1i }).join(), 1); }
|
|
|
|
#[test]
|
|
fn detached() { Thread::spawn(proc () {}) }
|
|
|
|
#[test]
|
|
fn small_stacks() {
|
|
assert_eq!(42i, Thread::start_stack(0, proc () 42i).join());
|
|
assert_eq!(42i, Thread::start_stack(1, proc () 42i).join());
|
|
}
|
|
}
|