fre_rs/
data.rs

1//! 
2//! This module provides safe conversions between concrete typed instances
3//! and raw pointers for native data.
4//! 
5//! [`Box<dyn Any>`] is a fat pointer stored on the stack. Casting it directly
6//! to a raw pointer will truncate its metadata. To preserve type information,
7//! the fat pointer must be stored intact on the heap, so it can be safely
8//! reconstructed from a raw pointer.
9//! 
10
11
12use super::*;
13
14
15pub(crate) type ExtensionData = Arc<Mutex<Box<dyn Any>>>;
16impl Data for ExtensionData {}
17
18
19/// Should be implemented for all native data types to ensure safe pointer passing
20/// and correct memory management. Native data includes Extension Data, Context Data,
21/// and Function data.
22/// 
23pub trait Data: 'static + Sized {
24    fn into_boxed (self) -> Box<dyn Any> {
25        Box::new(self) as Box<dyn Any>
26    }
27
28    fn from_boxed (boxed: Box<dyn Any>) -> Result<Self, Box<dyn Any>> {
29        boxed.downcast()
30            .map(|b| *b)
31            .map_err(|b| b)
32    }
33
34    /// **In typical usage of this crate, this function should not be called directly.**
35    /// 
36    fn into_raw (self) -> NonNullFREData {
37        super::data::into_raw(self.into_boxed())
38    }
39
40    /// **In typical usage of this crate, this function should not be called directly.**
41    /// 
42    #[allow(unsafe_op_in_unsafe_fn)]
43    unsafe fn from_raw (raw: NonNullFREData) -> Self {
44        let boxed = super::data::from_raw(raw);
45        Self::from_boxed(boxed).unwrap()
46    }
47
48    /// **In typical usage of this crate, this function should not be called directly.**
49    /// 
50    /// # Safety
51    /// 
52    /// The returned reference has an unbounded lifetime and is not tied to any input.
53    /// Correct and safe usage requires the caller to impose additional lifetime constraints.
54    /// 
55    #[allow(unsafe_op_in_unsafe_fn)]
56    unsafe fn ref_from <'a> (raw: NonNullFREData) -> Result<&'a Self, &'a dyn Any> {
57        let any = super::data::ref_from(raw);
58        any.downcast_ref().ok_or(any)
59    }
60
61    /// **In typical usage of this crate, this function should not be called directly.**
62    /// 
63    /// # Safety
64    /// 
65    /// The returned reference has an unbounded lifetime and is not tied to any input.
66    /// Correct and safe usage requires the caller to impose additional lifetime constraints.
67    /// 
68    #[allow(unsafe_op_in_unsafe_fn)]
69    unsafe fn mut_from <'a> (raw: NonNullFREData) -> Result<&'a mut Self, &'a mut dyn Any> {
70        let fat = super::data::mut_from(raw) as *mut dyn Any;
71        (&mut (*fat)).downcast_mut().ok_or(&mut (*fat))
72    }
73}
74
75
76type DataPointer = *mut *mut (dyn Any + 'static);
77
78
79/// **In typical usage of this crate, this function should not be called directly.**
80/// 
81pub fn into_raw (boxed: Box<dyn Any>) -> NonNullFREData {
82    let fat = Box::into_raw(boxed);
83    let raw: DataPointer = Box::into_raw(Box::new(fat));
84    unsafe {NonNull::new_unchecked(raw as FREData)}
85}
86
87/// **In typical usage of this crate, this function should not be called directly.**
88/// 
89#[allow(unsafe_op_in_unsafe_fn)]
90pub unsafe fn from_raw (raw: NonNullFREData) -> Box<dyn Any> {
91    let raw = raw.as_ptr() as DataPointer;
92    let fat = Box::from_raw(raw);
93    let boxed = Box::from_raw(*fat);
94    boxed
95}
96
97/// **In typical usage of this crate, this function should not be called directly.**
98/// 
99/// # Safety
100/// 
101/// The returned reference has an unbounded lifetime and is not tied to any input.
102/// Correct and safe usage requires the caller to impose additional lifetime constraints.
103/// 
104#[allow(unsafe_op_in_unsafe_fn)]
105pub unsafe fn ref_from <'a> (raw: NonNullFREData) -> &'a dyn Any {
106    let raw = raw.as_ptr() as DataPointer;
107    let any = &(**raw);
108    any
109}
110
111/// **In typical usage of this crate, this function should not be called directly.**
112/// 
113/// # Safety
114/// 
115/// The returned reference has an unbounded lifetime and is not tied to any input.
116/// Correct and safe usage requires the caller to impose additional lifetime constraints.
117/// 
118#[allow(unsafe_op_in_unsafe_fn)]
119pub unsafe fn mut_from <'a> (raw: NonNullFREData) -> &'a mut dyn Any {
120    let raw = raw.as_ptr() as DataPointer;
121    let any = &mut (**raw);
122    any
123}
124
125/// **In typical usage of this crate, this function should not be called directly.**
126/// 
127#[allow(unsafe_op_in_unsafe_fn)]
128pub unsafe fn drop_from (raw: NonNullFREData) {
129    drop(from_raw(raw));
130}
fre_rs/data.rs

fre_rs/
data.rs
