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
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
use crate::runtime::task::{Cell, Harness, Header, Schedule, State};
use std::future::Future;
use std::ptr::NonNull;
use std::task::{Poll, Waker};
/// Raw task handle
pub(super) struct RawTask {
ptr: NonNull<Header>,
}
pub(super) struct Vtable {
/// Poll the future
pub(super) poll: unsafe fn(NonNull<Header>),
/// Deallocate the memory
pub(super) dealloc: unsafe fn(NonNull<Header>),
/// Read the task output, if complete
pub(super) try_read_output: unsafe fn(NonNull<Header>, *mut (), &Waker),
/// The join handle has been dropped
pub(super) drop_join_handle_slow: unsafe fn(NonNull<Header>),
/// Scheduler is being shutdown
pub(super) shutdown: unsafe fn(NonNull<Header>),
}
/// Get the vtable for the requested `T` and `S` generics.
pub(super) fn vtable<T: Future, S: Schedule>() -> &'static Vtable {
&Vtable {
poll: poll::<T, S>,
dealloc: dealloc::<T, S>,
try_read_output: try_read_output::<T, S>,
drop_join_handle_slow: drop_join_handle_slow::<T, S>,
shutdown: shutdown::<T, S>,
}
}
impl RawTask {
pub(super) fn new<T, S>(task: T) -> RawTask
where
T: Future,
S: Schedule,
{
let ptr = Box::into_raw(Cell::<_, S>::new(task, State::new()));
let ptr = unsafe { NonNull::new_unchecked(ptr as *mut Header) };
RawTask { ptr }
}
pub(super) unsafe fn from_raw(ptr: NonNull<Header>) -> RawTask {
RawTask { ptr }
}
/// Returns a reference to the task's meta structure.
///
/// Safe as `Header` is `Sync`.
pub(super) fn header(&self) -> &Header {
unsafe { self.ptr.as_ref() }
}
/// Safety: mutual exclusion is required to call this function.
pub(super) fn poll(self) {
let vtable = self.header().vtable;
unsafe { (vtable.poll)(self.ptr) }
}
pub(super) fn dealloc(self) {
let vtable = self.header().vtable;
unsafe {
(vtable.dealloc)(self.ptr);
}
}
/// Safety: `dst` must be a `*mut Poll<super::Result<T::Output>>` where `T`
/// is the future stored by the task.
pub(super) unsafe fn try_read_output(self, dst: *mut (), waker: &Waker) {
let vtable = self.header().vtable;
(vtable.try_read_output)(self.ptr, dst, waker);
}
pub(super) fn drop_join_handle_slow(self) {
let vtable = self.header().vtable;
unsafe { (vtable.drop_join_handle_slow)(self.ptr) }
}
pub(super) fn shutdown(self) {
let vtable = self.header().vtable;
unsafe { (vtable.shutdown)(self.ptr) }
}
}
impl Clone for RawTask {
fn clone(&self) -> Self {
RawTask { ptr: self.ptr }
}
}
impl Copy for RawTask {}
unsafe fn poll<T: Future, S: Schedule>(ptr: NonNull<Header>) {
let harness = Harness::<T, S>::from_raw(ptr);
harness.poll();
}
unsafe fn dealloc<T: Future, S: Schedule>(ptr: NonNull<Header>) {
let harness = Harness::<T, S>::from_raw(ptr);
harness.dealloc();
}
unsafe fn try_read_output<T: Future, S: Schedule>(
ptr: NonNull<Header>,
dst: *mut (),
waker: &Waker,
) {
let out = &mut *(dst as *mut Poll<super::Result<T::Output>>);
let harness = Harness::<T, S>::from_raw(ptr);
harness.try_read_output(out, waker);
}
unsafe fn drop_join_handle_slow<T: Future, S: Schedule>(ptr: NonNull<Header>) {
let harness = Harness::<T, S>::from_raw(ptr);
harness.drop_join_handle_slow()
}
unsafe fn shutdown<T: Future, S: Schedule>(ptr: NonNull<Header>) {
let harness = Harness::<T, S>::from_raw(ptr);
harness.shutdown()
}
|
