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

use core::marker::PhantomData;
#[cfg(feature = "host")]
use std::mem::ManuallyDrop;

use const_type_layout::{TypeGraphLayout, TypeLayout};

#[cfg(feature = "host")]
use rustacuda::{error::CudaResult, memory::DeviceBox, memory::LockedBox};

use crate::{
    lend::{CudaAsRust, RustToCuda, RustToCudaAsync},
    safety::PortableBitSemantics,
    utils::ffi::DeviceConstPointer,
};

#[cfg(any(feature = "host", feature = "device"))]
use crate::utils::ffi::DeviceAccessible;

#[cfg(feature = "host")]
use crate::{
    alloc::{CombinedCudaAlloc, CudaAlloc},
    host::CudaDropWrapper,
    utils::adapter::DeviceCopyWithPortableBitSemantics,
    utils::r#async::{Async, CompletionFnMut, NoCompletion},
};

#[doc(hidden)]
#[repr(transparent)]
#[derive(TypeLayout)]
#[expect(clippy::module_name_repetitions)]
pub struct RefCudaRepresentation<'a, T: 'a + PortableBitSemantics + TypeGraphLayout> {
    data: DeviceConstPointer<T>,
    _marker: PhantomData<&'a T>,
}

unsafe impl<'a, T: PortableBitSemantics + TypeGraphLayout> RustToCuda for &'a T {
    #[cfg(all(feature = "host", not(doc)))]
    type CudaAllocation = CudaDropWrapper<DeviceBox<DeviceCopyWithPortableBitSemantics<T>>>;
    #[cfg(any(not(feature = "host"), doc))]
    type CudaAllocation = crate::alloc::SomeCudaAlloc;
    type CudaRepresentation = RefCudaRepresentation<'a, T>;

    #[cfg(feature = "host")]
    unsafe fn borrow<A: CudaAlloc>(
        &self,
        alloc: A,
    ) -> CudaResult<(
        DeviceAccessible<Self::CudaRepresentation>,
        CombinedCudaAlloc<Self::CudaAllocation, A>,
    )> {
        let mut device_box = CudaDropWrapper::from(DeviceBox::new(
            DeviceCopyWithPortableBitSemantics::from_ref(&**self),
        )?);

        Ok((
            DeviceAccessible::from(RefCudaRepresentation {
                data: DeviceConstPointer(device_box.as_device_ptr().as_raw().cast()),
                _marker: PhantomData::<&'a T>,
            }),
            CombinedCudaAlloc::new(device_box, alloc),
        ))
    }

    #[cfg(feature = "host")]
    unsafe fn restore<A: CudaAlloc>(
        &mut self,
        alloc: CombinedCudaAlloc<Self::CudaAllocation, A>,
    ) -> CudaResult<A> {
        let (_alloc_front, alloc_tail) = alloc.split();
        Ok(alloc_tail)
    }
}

unsafe impl<'a, T: PortableBitSemantics + TypeGraphLayout> RustToCudaAsync for &'a T {
    #[cfg(all(feature = "host", not(doc)))]
    type CudaAllocationAsync = CombinedCudaAlloc<
        CudaDropWrapper<LockedBox<DeviceCopyWithPortableBitSemantics<ManuallyDrop<T>>>>,
        CudaDropWrapper<DeviceBox<DeviceCopyWithPortableBitSemantics<ManuallyDrop<T>>>>,
    >;
    #[cfg(any(not(feature = "host"), doc))]
    type CudaAllocationAsync = crate::alloc::SomeCudaAlloc;

    #[cfg(feature = "host")]
    unsafe fn borrow_async<'stream, A: CudaAlloc>(
        &self,
        alloc: A,
        stream: crate::host::Stream<'stream>,
    ) -> rustacuda::error::CudaResult<(
        Async<'_, 'stream, DeviceAccessible<Self::CudaRepresentation>>,
        CombinedCudaAlloc<Self::CudaAllocationAsync, A>,
    )> {
        use rustacuda::memory::AsyncCopyDestination;

        let locked_box = unsafe {
            let mut uninit = CudaDropWrapper::from(LockedBox::<
                DeviceCopyWithPortableBitSemantics<ManuallyDrop<T>>,
            >::uninitialized()?);
            std::ptr::copy_nonoverlapping(
                std::ptr::from_ref::<T>(&**self)
                    .cast::<DeviceCopyWithPortableBitSemantics<ManuallyDrop<T>>>(),
                uninit.as_mut_ptr(),
                1,
            );
            uninit
        };

        let mut device_box = CudaDropWrapper::from(DeviceBox::<
            DeviceCopyWithPortableBitSemantics<ManuallyDrop<T>>,
        >::uninitialized()?);
        device_box.async_copy_from(&*locked_box, &stream)?;

        Ok((
            Async::pending(
                DeviceAccessible::from(RefCudaRepresentation {
                    data: DeviceConstPointer(device_box.as_device_ptr().as_raw().cast()),
                    _marker: PhantomData::<&T>,
                }),
                stream,
                NoCompletion,
            )?,
            CombinedCudaAlloc::new(CombinedCudaAlloc::new(locked_box, device_box), alloc),
        ))
    }

    #[cfg(feature = "host")]
    unsafe fn restore_async<'b, 'stream, A: CudaAlloc, O>(
        this: owning_ref::BoxRefMut<'b, O, Self>,
        alloc: CombinedCudaAlloc<Self::CudaAllocationAsync, A>,
        stream: crate::host::Stream<'stream>,
    ) -> CudaResult<(
        Async<'b, 'stream, owning_ref::BoxRefMut<'b, O, Self>, CompletionFnMut<'b, Self>>,
        A,
    )> {
        let (_alloc_front, alloc_tail) = alloc.split();
        let r#async = Async::ready(this, stream);
        Ok((r#async, alloc_tail))
    }
}

unsafe impl<'a, T: PortableBitSemantics + TypeGraphLayout> CudaAsRust
    for RefCudaRepresentation<'a, T>
{
    type RustRepresentation = &'a T;

    #[cfg(feature = "device")]
    unsafe fn as_rust(this: &DeviceAccessible<Self>) -> Self::RustRepresentation {
        &*this.data.0
    }
}