1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
|
// Copyright 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.
use prelude::v1::*;
use sync::atomic;
use alloc::{self, heap};
use libc::DWORD;
use sys::sync as ffi;
const SPIN_COUNT: DWORD = 4000;
pub struct Mutex { inner: atomic::AtomicUint }
pub const MUTEX_INIT: Mutex = Mutex { inner: atomic::ATOMIC_UINT_INIT };
unsafe impl Sync for Mutex {}
#[inline]
pub unsafe fn raw(m: &Mutex) -> ffi::LPCRITICAL_SECTION {
m.get()
}
impl Mutex {
#[inline]
pub unsafe fn new() -> Mutex {
Mutex { inner: atomic::AtomicUint::new(init_lock() as uint) }
}
#[inline]
pub unsafe fn lock(&self) {
ffi::EnterCriticalSection(self.get())
}
#[inline]
pub unsafe fn try_lock(&self) -> bool {
ffi::TryEnterCriticalSection(self.get()) != 0
}
#[inline]
pub unsafe fn unlock(&self) {
ffi::LeaveCriticalSection(self.get())
}
pub unsafe fn destroy(&self) {
let lock = self.inner.swap(0, atomic::SeqCst);
if lock != 0 { free_lock(lock as ffi::LPCRITICAL_SECTION) }
}
unsafe fn get(&self) -> ffi::LPCRITICAL_SECTION {
match self.inner.load(atomic::SeqCst) {
0 => {}
n => return n as ffi::LPCRITICAL_SECTION
}
let lock = init_lock();
match self.inner.compare_and_swap(0, lock as uint, atomic::SeqCst) {
0 => return lock as ffi::LPCRITICAL_SECTION,
_ => {}
}
free_lock(lock);
return self.inner.load(atomic::SeqCst) as ffi::LPCRITICAL_SECTION;
}
}
unsafe fn init_lock() -> ffi::LPCRITICAL_SECTION {
let block = heap::allocate(ffi::CRITICAL_SECTION_SIZE, 8)
as ffi::LPCRITICAL_SECTION;
if block.is_null() { alloc::oom() }
ffi::InitializeCriticalSectionAndSpinCount(block, SPIN_COUNT);
return block;
}
unsafe fn free_lock(h: ffi::LPCRITICAL_SECTION) {
ffi::DeleteCriticalSection(h);
heap::deallocate(h as *mut _, ffi::CRITICAL_SECTION_SIZE, 8);
}
|
