nulib.threading.internal.semaphore source code

1 /**
2     Native Semaphore Abstraction
3 
4     Copyright:
5         Copyright © 2023-2025, Kitsunebi Games
6         Copyright © 2023-2025, Inochi2D Project
7     
8     License:   $(LINK2 http://www.boost.org/LICENSE_1_0.txt, Boost License 1.0)
9     Authors:   Luna Nielsen
10 */
11 module nulib.threading.internal.semaphore;
12 import numem;
13 
14 /**
15     Native implementation of a semaphore.
16 */
17 export
18 abstract
19 class NativeSemaphore : NuObject {
20 public:
21 @nogc:
22 
23     /**
24         Creates a new native semaphore using a linked backend.
25 
26         Returns:
27             A new $(D NativeSemaphore) or $(D null) if the
28             platform does not support mutexes.
29     */
30     static NativeSemaphore create(uint count) => _nu_semaphore_new(count);
31 
32     /**
33         Signals the semaphore.
34 
35         Note:
36             Control is not transferred to the waiter.
37     */
38     abstract void signal();
39 
40     /**
41         Suspends the thread until the semaphore is signaled,
42         or the timeout is reached.
43 
44         Params:
45             timeout =   Timeout in miliseconds to block the 
46                         calling thread before giving up.
47 
48         Returns:
49             $(D true) if the semaphore was signaled in time,
50             $(D false) otherwise.
51     */
52     abstract bool await(ulong timeout = 0);
53 
54     /**
55         Checks if the semaphore is signalled then
56         awaits on it if is.
57 
58         Returns:
59             $(D true) if the semaphore was signalled,
60             $(D false) otherwise.
61     */
62     abstract bool tryAwait();
63 }
64 
65 //
66 //          FOR IMPLEMENTORS
67 //
68 
69 private extern(C):
70 import core.attribute : weak;
71 
72 version(DigitalMars) version = WeakIsBroken;
73 version(linux) version = WeakIsBroken;
74 version(WeakIsBroken) {
75 
76     // Needed on Linux because we can't specify load order.
77     extern(C) extern NativeSemaphore _nu_semaphore_new(uint count) @nogc nothrow;
78 } else {
79 
80     /*
81         Function which creates a new native semaphore.
82     */
83     NativeSemaphore _nu_semaphore_new(uint count) @weak @nogc nothrow { return null; }
84 }