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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164

use std::future::Future;
use std::marker::PhantomData;
use std::pin::Pin;
use std::sync::Mutex;
use std::task::{Context, Poll};
pub use directcpp_macro::bridge;
pub use directcpp_macro::enable_msvc_debug;

// implies the value is POD so no dtor is needed, it's just copied.
#[doc(hidden)]
pub struct POD<T>(T);

#[doc(hidden)]
pub trait ManDtor {
	unsafe fn __dtor(ptr: *mut [u8;0]);
}

#[doc(hidden)]
pub trait DropSP {
	unsafe fn __drop_sp(sp_ptr: *mut [u8;0]);
}

#[repr(C)]
pub struct SharedPtr<T> where T: DropSP {
	val1: usize,
	val2: usize,
    _phantom: PhantomData<T>,
}
impl<T> Default for SharedPtr<T> where T: DropSP {
	fn default() -> Self {
		Self {
			val1: 0,
			val2: 0,
			_phantom: PhantomData,
		}
	}
}
impl<T> Drop for SharedPtr<T> where T: DropSP {
	fn drop(&mut self) {
		unsafe {
			T::__drop_sp(self as *mut SharedPtr<T> as *mut [u8;0]);
		}
	}
}

#[repr(C)]
pub struct UniquePtr<T> where T: ManDtor {
	val1: usize,
	_phantom: PhantomData<T>,
}
impl<T> Default for UniquePtr<T> where T: ManDtor {
	fn default() -> Self {
		Self {
			val1: 0,
			_phantom: PhantomData,
		}
	}
}
impl<T> Drop for UniquePtr<T> where T: ManDtor {
	fn drop(&mut self) {
		unsafe {
			if self.val1 != 0 {
				T::__dtor(self.val1 as *mut [u8; 0]);
			}
		}
	}
}

#[repr(C)]
#[derive(Clone, Debug, Default)]
pub struct CPtr<T> {
	pub addr: usize,
	_phantom: PhantomData<T>,
}

pub trait AsCPtr<T> {
	fn as_cptr(&self) -> CPtr<T>;
}

impl<T> AsCPtr<T>  for SharedPtr<T>
	where T:DropSP
{
	fn as_cptr(&self) -> CPtr<T> {
		CPtr::<T> {
			addr: self.val1,
			_phantom: PhantomData
		}
	}
}

impl<T> AsCPtr<T> for UniquePtr<T>
	where T: ManDtor
{
	fn as_cptr(&self) -> CPtr<T> {
		CPtr::<T> {
			addr: self.val1,
			_phantom: PhantomData
		}
	}
}

pub trait ValuePromise {
	type Output;
	fn set_value(&self, value: &Self::Output);
}


struct FutureValueInner<T> {
	value: Option<T>,
	waker: Option<std::task::Waker>,
}
pub struct FutureValue<T> {
	value: Mutex<FutureValueInner<T>>
}

impl<T> Future for FutureValue<T> {
	type Output = T;

	fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
		let mut lock = self.value.lock().unwrap();
		match lock.value.take() {
			Some(ss) => Poll::Ready(ss),
			None => {
				lock.waker = Some(cx.waker().clone());
				Poll::Pending
			}
		}
	}
}
impl<T> Default for FutureValue<T> {
	fn default() -> Self {
		Self {
			value: Mutex::new(FutureValueInner {
				value: None,
				waker: None,
			})
		}
	}
}

impl<T> ValuePromise for FutureValue<T> where T: Clone {
	type Output = T;

	fn set_value(&self, value: &T) {
		let mut lock = self.value.lock().unwrap();
		lock.value = Some(value.clone());
		if let Some(w) = lock.waker.as_ref() {
			w.wake_by_ref();
		}
	}
}

impl<T> FutureValue<T> where T: Clone {
	pub fn copy_vtbl(self: &mut Pin<&mut Self>, arr: &mut [usize;2]) -> usize {
		static_assertions::assert_eq_size!([usize;2], &dyn ValuePromise<Output=String>);
		let fv = self.as_ref().get_ref() as &dyn ValuePromise<Output=T>;
		let ptr = &fv as *const &dyn ValuePromise<Output=T> as *const [usize;2];
		unsafe {
			arr[0] = (*ptr)[0];
			arr[1] = (*ptr)[1];
			arr as *mut [usize;2] as usize
		}
	}
}