1 // SPDX-License-Identifier: Apache-2.0 OR MIT 1 // SPDX-License-Identifier: Apache-2.0 OR MIT
2 2
3 //! This module provides the macros that actua 3 //! This module provides the macros that actually implement the proc-macros `pin_data` and
4 //! `pinned_drop`. It also contains `__init_in !! 4 //! `pinned_drop`.
5 //! macros. <<
6 //! 5 //!
7 //! These macros should never be called direct 6 //! These macros should never be called directly, since they expect their input to be
8 //! in a certain format which is internal. If !! 7 //! in a certain format which is internal. Use the proc-macros instead.
9 //! safe code! Use the public facing macros in <<
10 //! 8 //!
11 //! This architecture has been chosen because 9 //! This architecture has been chosen because the kernel does not yet have access to `syn` which
12 //! would make matters a lot easier for implem 10 //! would make matters a lot easier for implementing these as proc-macros.
13 //! 11 //!
14 //! # Macro expansion example 12 //! # Macro expansion example
15 //! 13 //!
16 //! This section is intended for readers tryin 14 //! This section is intended for readers trying to understand the macros in this module and the
17 //! `pin_init!` macros from `init.rs`. 15 //! `pin_init!` macros from `init.rs`.
18 //! 16 //!
19 //! We will look at the following example: 17 //! We will look at the following example:
20 //! 18 //!
21 //! ```rust,ignore !! 19 //! ```rust
22 //! # use kernel::init::*; 20 //! # use kernel::init::*;
23 //! # use core::pin::Pin; <<
24 //! #[pin_data] 21 //! #[pin_data]
25 //! #[repr(C)] 22 //! #[repr(C)]
26 //! struct Bar<T> { 23 //! struct Bar<T> {
27 //! #[pin] 24 //! #[pin]
28 //! t: T, 25 //! t: T,
29 //! pub x: usize, 26 //! pub x: usize,
30 //! } 27 //! }
31 //! 28 //!
32 //! impl<T> Bar<T> { 29 //! impl<T> Bar<T> {
33 //! fn new(t: T) -> impl PinInit<Self> { 30 //! fn new(t: T) -> impl PinInit<Self> {
34 //! pin_init!(Self { t, x: 0 }) 31 //! pin_init!(Self { t, x: 0 })
35 //! } 32 //! }
36 //! } 33 //! }
37 //! 34 //!
38 //! #[pin_data(PinnedDrop)] 35 //! #[pin_data(PinnedDrop)]
39 //! struct Foo { 36 //! struct Foo {
40 //! a: usize, 37 //! a: usize,
41 //! #[pin] 38 //! #[pin]
42 //! b: Bar<u32>, 39 //! b: Bar<u32>,
43 //! } 40 //! }
44 //! 41 //!
45 //! #[pinned_drop] 42 //! #[pinned_drop]
46 //! impl PinnedDrop for Foo { 43 //! impl PinnedDrop for Foo {
47 //! fn drop(self: Pin<&mut Self>) { 44 //! fn drop(self: Pin<&mut Self>) {
48 //! pr_info!("{self:p} is getting drop !! 45 //! println!("{self:p} is getting dropped.");
49 //! } 46 //! }
50 //! } 47 //! }
51 //! 48 //!
52 //! let a = 42; 49 //! let a = 42;
53 //! let initializer = pin_init!(Foo { 50 //! let initializer = pin_init!(Foo {
54 //! a, 51 //! a,
55 //! b <- Bar::new(36), 52 //! b <- Bar::new(36),
56 //! }); 53 //! });
57 //! ``` 54 //! ```
58 //! 55 //!
59 //! This example includes the most common and 56 //! This example includes the most common and important features of the pin-init API.
60 //! 57 //!
61 //! Below you can find individual section abou 58 //! Below you can find individual section about the different macro invocations. Here are some
62 //! general things we need to take into accoun 59 //! general things we need to take into account when designing macros:
63 //! - use global paths, similarly to file path 60 //! - use global paths, similarly to file paths, these start with the separator: `::core::panic!()`
64 //! this ensures that the correct item is us 61 //! this ensures that the correct item is used, since users could define their own `mod core {}`
65 //! and then their own `panic!` inside to ex 62 //! and then their own `panic!` inside to execute arbitrary code inside of our macro.
66 //! - macro `unsafe` hygiene: we need to ensur 63 //! - macro `unsafe` hygiene: we need to ensure that we do not expand arbitrary, user-supplied
67 //! expressions inside of an `unsafe` block 64 //! expressions inside of an `unsafe` block in the macro, because this would allow users to do
68 //! `unsafe` operations without an associate 65 //! `unsafe` operations without an associated `unsafe` block.
69 //! 66 //!
70 //! ## `#[pin_data]` on `Bar` 67 //! ## `#[pin_data]` on `Bar`
71 //! 68 //!
72 //! This macro is used to specify which fields 69 //! This macro is used to specify which fields are structurally pinned and which fields are not. It
73 //! is placed on the struct definition and all 70 //! is placed on the struct definition and allows `#[pin]` to be placed on the fields.
74 //! 71 //!
75 //! Here is the definition of `Bar` from our e 72 //! Here is the definition of `Bar` from our example:
76 //! 73 //!
77 //! ```rust,ignore !! 74 //! ```rust
78 //! # use kernel::init::*; 75 //! # use kernel::init::*;
79 //! #[pin_data] 76 //! #[pin_data]
80 //! #[repr(C)] 77 //! #[repr(C)]
81 //! struct Bar<T> { 78 //! struct Bar<T> {
82 //! #[pin] <<
83 //! t: T, 79 //! t: T,
84 //! pub x: usize, 80 //! pub x: usize,
85 //! } 81 //! }
86 //! ``` 82 //! ```
87 //! 83 //!
88 //! This expands to the following code: 84 //! This expands to the following code:
89 //! 85 //!
90 //! ```rust,ignore !! 86 //! ```rust
91 //! // Firstly the normal definition of the st 87 //! // Firstly the normal definition of the struct, attributes are preserved:
92 //! #[repr(C)] 88 //! #[repr(C)]
93 //! struct Bar<T> { 89 //! struct Bar<T> {
94 //! t: T, 90 //! t: T,
95 //! pub x: usize, 91 //! pub x: usize,
96 //! } 92 //! }
97 //! // Then an anonymous constant is defined, 93 //! // Then an anonymous constant is defined, this is because we do not want any code to access the
98 //! // types that we define inside: 94 //! // types that we define inside:
99 //! const _: () = { 95 //! const _: () = {
100 //! // We define the pin-data carrying str 96 //! // We define the pin-data carrying struct, it is a ZST and needs to have the same generics,
101 //! // since we need to implement access f 97 //! // since we need to implement access functions for each field and thus need to know its
102 //! // type. 98 //! // type.
103 //! struct __ThePinData<T> { 99 //! struct __ThePinData<T> {
104 //! __phantom: ::core::marker::Phantom 100 //! __phantom: ::core::marker::PhantomData<fn(Bar<T>) -> Bar<T>>,
105 //! } 101 //! }
106 //! // We implement `Copy` for the pin-dat 102 //! // We implement `Copy` for the pin-data struct, since all functions it defines will take
107 //! // `self` by value. 103 //! // `self` by value.
108 //! impl<T> ::core::clone::Clone for __The 104 //! impl<T> ::core::clone::Clone for __ThePinData<T> {
109 //! fn clone(&self) -> Self { 105 //! fn clone(&self) -> Self {
110 //! *self 106 //! *self
111 //! } 107 //! }
112 //! } 108 //! }
113 //! impl<T> ::core::marker::Copy for __The 109 //! impl<T> ::core::marker::Copy for __ThePinData<T> {}
114 //! // For every field of `Bar`, the pin-d 110 //! // For every field of `Bar`, the pin-data struct will define a function with the same name
115 //! // and accessor (`pub` or `pub(crate)` 111 //! // and accessor (`pub` or `pub(crate)` etc.). This function will take a pointer to the
116 //! // field (`slot`) and a `PinInit` or ` 112 //! // field (`slot`) and a `PinInit` or `Init` depending on the projection kind of the field
117 //! // (if pinning is structural for the f 113 //! // (if pinning is structural for the field, then `PinInit` otherwise `Init`).
118 //! #[allow(dead_code)] 114 //! #[allow(dead_code)]
119 //! impl<T> __ThePinData<T> { 115 //! impl<T> __ThePinData<T> {
120 //! unsafe fn t<E>( 116 //! unsafe fn t<E>(
121 //! self, 117 //! self,
122 //! slot: *mut T, 118 //! slot: *mut T,
123 //! // Since `t` is `#[pin]`, this !! 119 //! init: impl ::kernel::init::Init<T, E>,
124 //! init: impl ::kernel::init::Pin <<
125 //! ) -> ::core::result::Result<(), E> 120 //! ) -> ::core::result::Result<(), E> {
126 //! unsafe { ::kernel::init::PinIn !! 121 //! unsafe { ::kernel::init::Init::__init(init, slot) }
127 //! } 122 //! }
128 //! pub unsafe fn x<E>( 123 //! pub unsafe fn x<E>(
129 //! self, 124 //! self,
130 //! slot: *mut usize, 125 //! slot: *mut usize,
131 //! // Since `x` is not `#[pin]`, <<
132 //! init: impl ::kernel::init::Ini 126 //! init: impl ::kernel::init::Init<usize, E>,
133 //! ) -> ::core::result::Result<(), E> 127 //! ) -> ::core::result::Result<(), E> {
134 //! unsafe { ::kernel::init::Init: 128 //! unsafe { ::kernel::init::Init::__init(init, slot) }
135 //! } 129 //! }
136 //! } 130 //! }
137 //! // Implement the internal `HasPinData` 131 //! // Implement the internal `HasPinData` trait that associates `Bar` with the pin-data struct
138 //! // that we constructed above. !! 132 //! // that we constructed beforehand.
139 //! unsafe impl<T> ::kernel::init::__inter 133 //! unsafe impl<T> ::kernel::init::__internal::HasPinData for Bar<T> {
140 //! type PinData = __ThePinData<T>; 134 //! type PinData = __ThePinData<T>;
141 //! unsafe fn __pin_data() -> Self::Pi 135 //! unsafe fn __pin_data() -> Self::PinData {
142 //! __ThePinData { 136 //! __ThePinData {
143 //! __phantom: ::core::marker: 137 //! __phantom: ::core::marker::PhantomData,
144 //! } 138 //! }
145 //! } 139 //! }
146 //! } 140 //! }
147 //! // Implement the internal `PinData` tr 141 //! // Implement the internal `PinData` trait that marks the pin-data struct as a pin-data
148 //! // struct. This is important to ensure !! 142 //! // struct. This is important to ensure that no user can implement a rouge `__pin_data`
149 //! // function without using `unsafe`. 143 //! // function without using `unsafe`.
150 //! unsafe impl<T> ::kernel::init::__inter 144 //! unsafe impl<T> ::kernel::init::__internal::PinData for __ThePinData<T> {
151 //! type Datee = Bar<T>; 145 //! type Datee = Bar<T>;
152 //! } 146 //! }
153 //! // Now we only want to implement `Unpi 147 //! // Now we only want to implement `Unpin` for `Bar` when every structurally pinned field is
154 //! // `Unpin`. In other words, whether `B 148 //! // `Unpin`. In other words, whether `Bar` is `Unpin` only depends on structurally pinned
155 //! // fields (those marked with `#[pin]`) 149 //! // fields (those marked with `#[pin]`). These fields will be listed in this struct, in our
156 //! // case no such fields exist, hence th 150 //! // case no such fields exist, hence this is almost empty. The two phantomdata fields exist
157 //! // for two reasons: 151 //! // for two reasons:
158 //! // - `__phantom`: every generic must b 152 //! // - `__phantom`: every generic must be used, since we cannot really know which generics
159 //! // are used, we declare all and then !! 153 //! // are used, we declere all and then use everything here once.
160 //! // - `__phantom_pin`: uses the `'__pin 154 //! // - `__phantom_pin`: uses the `'__pin` lifetime and ensures that this struct is invariant
161 //! // over it. The lifetime is needed t 155 //! // over it. The lifetime is needed to work around the limitation that trait bounds must
162 //! // not be trivial, e.g. the user has 156 //! // not be trivial, e.g. the user has a `#[pin] PhantomPinned` field -- this is
163 //! // unconditionally `!Unpin` and resu 157 //! // unconditionally `!Unpin` and results in an error. The lifetime tricks the compiler
164 //! // into accepting these bounds regar 158 //! // into accepting these bounds regardless.
165 //! #[allow(dead_code)] 159 //! #[allow(dead_code)]
166 //! struct __Unpin<'__pin, T> { 160 //! struct __Unpin<'__pin, T> {
167 //! __phantom_pin: ::core::marker::Pha 161 //! __phantom_pin: ::core::marker::PhantomData<fn(&'__pin ()) -> &'__pin ()>,
168 //! __phantom: ::core::marker::Phantom 162 //! __phantom: ::core::marker::PhantomData<fn(Bar<T>) -> Bar<T>>,
169 //! // Our only `#[pin]` field is `t`. <<
170 //! t: T, <<
171 //! } 163 //! }
172 //! #[doc(hidden)] 164 //! #[doc(hidden)]
173 //! impl<'__pin, T> ::core::marker::Unpin !! 165 //! impl<'__pin, T>
174 //! where !! 166 //! ::core::marker::Unpin for Bar<T> where __Unpin<'__pin, T>: ::core::marker::Unpin {}
175 //! __Unpin<'__pin, T>: ::core::marker <<
176 //! {} <<
177 //! // Now we need to ensure that `Bar` do 167 //! // Now we need to ensure that `Bar` does not implement `Drop`, since that would give users
178 //! // access to `&mut self` inside of `dr 168 //! // access to `&mut self` inside of `drop` even if the struct was pinned. This could lead to
179 //! // UB with only safe code, so we disal 169 //! // UB with only safe code, so we disallow this by giving a trait implementation error using
180 //! // a direct impl and a blanket impleme 170 //! // a direct impl and a blanket implementation.
181 //! trait MustNotImplDrop {} 171 //! trait MustNotImplDrop {}
182 //! // Normally `Drop` bounds do not have 172 //! // Normally `Drop` bounds do not have the correct semantics, but for this purpose they do
183 //! // (normally people want to know if a 173 //! // (normally people want to know if a type has any kind of drop glue at all, here we want
184 //! // to know if it has any kind of custo 174 //! // to know if it has any kind of custom drop glue, which is exactly what this bound does).
185 //! #[allow(drop_bounds)] 175 //! #[allow(drop_bounds)]
186 //! impl<T: ::core::ops::Drop> MustNotImpl 176 //! impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
187 //! impl<T> MustNotImplDrop for Bar<T> {} 177 //! impl<T> MustNotImplDrop for Bar<T> {}
188 //! // Here comes a convenience check, if 178 //! // Here comes a convenience check, if one implemented `PinnedDrop`, but forgot to add it to
189 //! // `#[pin_data]`, then this will error 179 //! // `#[pin_data]`, then this will error with the same mechanic as above, this is not needed
190 //! // for safety, but a good sanity check 180 //! // for safety, but a good sanity check, since no normal code calls `PinnedDrop::drop`.
191 //! #[allow(non_camel_case_types)] 181 //! #[allow(non_camel_case_types)]
192 //! trait UselessPinnedDropImpl_you_need_t 182 //! trait UselessPinnedDropImpl_you_need_to_specify_PinnedDrop {}
193 //! impl< !! 183 //! impl<T: ::kernel::init::PinnedDrop>
194 //! T: ::kernel::init::PinnedDrop, !! 184 //! UselessPinnedDropImpl_you_need_to_specify_PinnedDrop for T {}
195 //! > UselessPinnedDropImpl_you_need_to_sp <<
196 //! impl<T> UselessPinnedDropImpl_you_need 185 //! impl<T> UselessPinnedDropImpl_you_need_to_specify_PinnedDrop for Bar<T> {}
197 //! }; 186 //! };
198 //! ``` 187 //! ```
199 //! 188 //!
200 //! ## `pin_init!` in `impl Bar` 189 //! ## `pin_init!` in `impl Bar`
201 //! 190 //!
202 //! This macro creates an pin-initializer for 191 //! This macro creates an pin-initializer for the given struct. It requires that the struct is
203 //! annotated by `#[pin_data]`. 192 //! annotated by `#[pin_data]`.
204 //! 193 //!
205 //! Here is the impl on `Bar` defining the new 194 //! Here is the impl on `Bar` defining the new function:
206 //! 195 //!
207 //! ```rust,ignore !! 196 //! ```rust
208 //! impl<T> Bar<T> { 197 //! impl<T> Bar<T> {
209 //! fn new(t: T) -> impl PinInit<Self> { 198 //! fn new(t: T) -> impl PinInit<Self> {
210 //! pin_init!(Self { t, x: 0 }) 199 //! pin_init!(Self { t, x: 0 })
211 //! } 200 //! }
212 //! } 201 //! }
213 //! ``` 202 //! ```
214 //! 203 //!
215 //! This expands to the following code: 204 //! This expands to the following code:
216 //! 205 //!
217 //! ```rust,ignore !! 206 //! ```rust
218 //! impl<T> Bar<T> { 207 //! impl<T> Bar<T> {
219 //! fn new(t: T) -> impl PinInit<Self> { 208 //! fn new(t: T) -> impl PinInit<Self> {
220 //! { 209 //! {
221 //! // We do not want to allow arb 210 //! // We do not want to allow arbitrary returns, so we declare this type as the `Ok`
222 //! // return type and shadow it l 211 //! // return type and shadow it later when we insert the arbitrary user code. That way
223 //! // there will be no possibilit 212 //! // there will be no possibility of returning without `unsafe`.
224 //! struct __InitOk; 213 //! struct __InitOk;
225 //! // Get the data about fields f !! 214 //! // Get the pin-data type from the initialized type.
226 //! // - the function is unsafe, h 215 //! // - the function is unsafe, hence the unsafe block
227 //! // - we `use` the `HasPinData` 216 //! // - we `use` the `HasPinData` trait in the block, it is only available in that
228 //! // scope. 217 //! // scope.
229 //! let data = unsafe { 218 //! let data = unsafe {
230 //! use ::kernel::init::__inte 219 //! use ::kernel::init::__internal::HasPinData;
231 //! Self::__pin_data() 220 //! Self::__pin_data()
232 //! }; 221 //! };
233 //! // Ensure that `data` really i !! 222 //! // Use `data` to help with type inference, the closure supplied will have the type
>> 223 //! // `FnOnce(*mut Self) -> Result<__InitOk, Infallible>`.
234 //! let init = ::kernel::init::__i 224 //! let init = ::kernel::init::__internal::PinData::make_closure::<
235 //! _, 225 //! _,
236 //! __InitOk, 226 //! __InitOk,
237 //! ::core::convert::Infallibl 227 //! ::core::convert::Infallible,
238 //! >(data, move |slot| { 228 //! >(data, move |slot| {
239 //! { 229 //! {
240 //! // Shadow the structur 230 //! // Shadow the structure so it cannot be used to return early. If a user
241 //! // tries to write `ret !! 231 //! // tries to write `return Ok(__InitOk)`, then they get a type error, since
242 //! // since that will ref !! 232 //! // that will refer to this struct instead of the one defined above.
243 //! // above. <<
244 //! struct __InitOk; 233 //! struct __InitOk;
245 //! // This is the expansi 234 //! // This is the expansion of `t,`, which is syntactic sugar for `t: t,`.
246 //! { !! 235 //! unsafe { ::core::ptr::write(&raw mut (*slot).t, t) };
247 //! unsafe { ::core::p !! 236 //! // Since initialization could fail later (not in this case, since the error
248 //! } !! 237 //! // type is `Infallible`) we will need to drop this field if it fails. This
249 //! // Since initializatio !! 238 //! // `DropGuard` will drop the field when it gets dropped and has not yet
250 //! // error type is `Infa !! 239 //! // been forgotten. We make a reference to it, so users cannot `mem::forget`
251 //! // is an error later. !! 240 //! // it from the initializer, since the name is the same as the field.
252 //! // dropped and has not !! 241 //! let t = &unsafe {
253 //! let __t_guard = unsafe !! 242 //! ::kernel::init::__internal::DropGuard::new(&raw mut (*slot).t)
254 //! ::pinned_init::__i <<
255 //! }; 243 //! };
256 //! // Expansion of `x: 0, 244 //! // Expansion of `x: 0,`:
257 //! // Since this can be a !! 245 //! // Since this can be an arbitrary expression we cannot place it inside of
258 //! // of the `unsafe` blo !! 246 //! // the `unsafe` block, so we bind it here.
259 //! { !! 247 //! let x = 0;
260 //! let x = 0; !! 248 //! unsafe { ::core::ptr::write(&raw mut (*slot).x, x) };
261 //! unsafe { ::core::p !! 249 //! let x = &unsafe {
262 //! } !! 250 //! ::kernel::init::__internal::DropGuard::new(&raw mut (*slot).x)
263 //! // We again create a ` <<
264 //! let __x_guard = unsafe <<
265 //! ::kernel::init::__ <<
266 //! }; 251 //! };
267 //! // Since initializatio !! 252 //!
268 //! // the guards. This is !! 253 //! // Here we use the type checker to ensuer that every field has been
269 //! // `&DropGuard`. <<
270 //! ::core::mem::forget(__ <<
271 //! ::core::mem::forget(__ <<
272 //! // Here we use the typ <<
273 //! // initialized exactly 254 //! // initialized exactly once, since this is `if false` it will never get
274 //! // executed, but still 255 //! // executed, but still type-checked.
275 //! // Additionally we abu !! 256 //! // Additionally we abuse `slot` to automatically infer the correct type for
276 //! // for the struct. Thi !! 257 //! // the struct. This is also another check that every field is accessible
277 //! // accessible from thi !! 258 //! // from this scope.
278 //! #[allow(unreachable_co 259 //! #[allow(unreachable_code, clippy::diverging_sub_expression)]
279 //! let _ = || { !! 260 //! if false {
280 //! unsafe { 261 //! unsafe {
281 //! ::core::ptr::w 262 //! ::core::ptr::write(
282 //! slot, 263 //! slot,
283 //! Self { 264 //! Self {
284 //! // We !! 265 //! // We only care about typecheck finding every field here,
285 //! // her !! 266 //! // the expression does not matter, just conjure one using
286 //! // one !! 267 //! // `panic!()`:
287 //! t: ::c 268 //! t: ::core::panic!(),
288 //! x: ::c 269 //! x: ::core::panic!(),
289 //! }, 270 //! },
290 //! ); 271 //! );
291 //! }; 272 //! };
292 //! }; !! 273 //! }
>> 274 //! // Since initialization has successfully completed, we can now forget the
>> 275 //! // guards.
>> 276 //! unsafe { ::kernel::init::__internal::DropGuard::forget(t) };
>> 277 //! unsafe { ::kernel::init::__internal::DropGuard::forget(x) };
293 //! } 278 //! }
294 //! // We leave the scope abov 279 //! // We leave the scope above and gain access to the previously shadowed
295 //! // `__InitOk` that we need 280 //! // `__InitOk` that we need to return.
296 //! Ok(__InitOk) 281 //! Ok(__InitOk)
297 //! }); 282 //! });
298 //! // Change the return type from !! 283 //! // Change the return type of the closure.
299 //! let init = move | !! 284 //! let init = move |slot| -> ::core::result::Result<(), ::core::convert::Infallible> {
300 //! slot, <<
301 //! | -> ::core::result::Result<() <<
302 //! init(slot).map(|__InitOk| 285 //! init(slot).map(|__InitOk| ())
303 //! }; 286 //! };
304 //! // Construct the initializer. 287 //! // Construct the initializer.
305 //! let init = unsafe { 288 //! let init = unsafe {
306 //! ::kernel::init::pin_init_f !! 289 //! ::kernel::init::pin_init_from_closure::<_, ::core::convert::Infallible>(init)
307 //! _, <<
308 //! ::core::convert::Infal <<
309 //! >(init) <<
310 //! }; 290 //! };
311 //! init 291 //! init
312 //! } 292 //! }
313 //! } 293 //! }
314 //! } 294 //! }
315 //! ``` 295 //! ```
316 //! 296 //!
317 //! ## `#[pin_data]` on `Foo` 297 //! ## `#[pin_data]` on `Foo`
318 //! 298 //!
319 //! Since we already took a look at `#[pin_dat 299 //! Since we already took a look at `#[pin_data]` on `Bar`, this section will only explain the
320 //! differences/new things in the expansion of 300 //! differences/new things in the expansion of the `Foo` definition:
321 //! 301 //!
322 //! ```rust,ignore !! 302 //! ```rust
323 //! #[pin_data(PinnedDrop)] 303 //! #[pin_data(PinnedDrop)]
324 //! struct Foo { 304 //! struct Foo {
325 //! a: usize, 305 //! a: usize,
326 //! #[pin] 306 //! #[pin]
327 //! b: Bar<u32>, 307 //! b: Bar<u32>,
328 //! } 308 //! }
329 //! ``` 309 //! ```
330 //! 310 //!
331 //! This expands to the following code: 311 //! This expands to the following code:
332 //! 312 //!
333 //! ```rust,ignore !! 313 //! ```rust
334 //! struct Foo { 314 //! struct Foo {
335 //! a: usize, 315 //! a: usize,
336 //! b: Bar<u32>, 316 //! b: Bar<u32>,
337 //! } 317 //! }
338 //! const _: () = { 318 //! const _: () = {
339 //! struct __ThePinData { 319 //! struct __ThePinData {
340 //! __phantom: ::core::marker::Phantom 320 //! __phantom: ::core::marker::PhantomData<fn(Foo) -> Foo>,
341 //! } 321 //! }
342 //! impl ::core::clone::Clone for __ThePin 322 //! impl ::core::clone::Clone for __ThePinData {
343 //! fn clone(&self) -> Self { 323 //! fn clone(&self) -> Self {
344 //! *self 324 //! *self
345 //! } 325 //! }
346 //! } 326 //! }
347 //! impl ::core::marker::Copy for __ThePin 327 //! impl ::core::marker::Copy for __ThePinData {}
348 //! #[allow(dead_code)] 328 //! #[allow(dead_code)]
349 //! impl __ThePinData { 329 //! impl __ThePinData {
350 //! unsafe fn b<E>( 330 //! unsafe fn b<E>(
351 //! self, 331 //! self,
352 //! slot: *mut Bar<u32>, 332 //! slot: *mut Bar<u32>,
>> 333 //! // Note that this is `PinInit` instead of `Init`, this is because `b` is
>> 334 //! // structurally pinned, as marked by the `#[pin]` attribute.
353 //! init: impl ::kernel::init::Pin 335 //! init: impl ::kernel::init::PinInit<Bar<u32>, E>,
354 //! ) -> ::core::result::Result<(), E> 336 //! ) -> ::core::result::Result<(), E> {
355 //! unsafe { ::kernel::init::PinIn 337 //! unsafe { ::kernel::init::PinInit::__pinned_init(init, slot) }
356 //! } 338 //! }
357 //! unsafe fn a<E>( 339 //! unsafe fn a<E>(
358 //! self, 340 //! self,
359 //! slot: *mut usize, 341 //! slot: *mut usize,
360 //! init: impl ::kernel::init::Ini 342 //! init: impl ::kernel::init::Init<usize, E>,
361 //! ) -> ::core::result::Result<(), E> 343 //! ) -> ::core::result::Result<(), E> {
362 //! unsafe { ::kernel::init::Init: 344 //! unsafe { ::kernel::init::Init::__init(init, slot) }
363 //! } 345 //! }
364 //! } 346 //! }
365 //! unsafe impl ::kernel::init::__internal 347 //! unsafe impl ::kernel::init::__internal::HasPinData for Foo {
366 //! type PinData = __ThePinData; 348 //! type PinData = __ThePinData;
367 //! unsafe fn __pin_data() -> Self::Pi 349 //! unsafe fn __pin_data() -> Self::PinData {
368 //! __ThePinData { 350 //! __ThePinData {
369 //! __phantom: ::core::marker: 351 //! __phantom: ::core::marker::PhantomData,
370 //! } 352 //! }
371 //! } 353 //! }
372 //! } 354 //! }
373 //! unsafe impl ::kernel::init::__internal 355 //! unsafe impl ::kernel::init::__internal::PinData for __ThePinData {
374 //! type Datee = Foo; 356 //! type Datee = Foo;
375 //! } 357 //! }
376 //! #[allow(dead_code)] 358 //! #[allow(dead_code)]
377 //! struct __Unpin<'__pin> { 359 //! struct __Unpin<'__pin> {
378 //! __phantom_pin: ::core::marker::Pha 360 //! __phantom_pin: ::core::marker::PhantomData<fn(&'__pin ()) -> &'__pin ()>,
379 //! __phantom: ::core::marker::Phantom 361 //! __phantom: ::core::marker::PhantomData<fn(Foo) -> Foo>,
>> 362 //! // Since this field is `#[pin]`, it is listed here.
380 //! b: Bar<u32>, 363 //! b: Bar<u32>,
381 //! } 364 //! }
382 //! #[doc(hidden)] 365 //! #[doc(hidden)]
383 //! impl<'__pin> ::core::marker::Unpin for !! 366 //! impl<'__pin> ::core::marker::Unpin for Foo where __Unpin<'__pin>: ::core::marker::Unpin {}
384 //! where <<
385 //! __Unpin<'__pin>: ::core::marker::U <<
386 //! {} <<
387 //! // Since we specified `PinnedDrop` as 367 //! // Since we specified `PinnedDrop` as the argument to `#[pin_data]`, we expect `Foo` to
388 //! // implement `PinnedDrop`. Thus we do 368 //! // implement `PinnedDrop`. Thus we do not need to prevent `Drop` implementations like
389 //! // before, instead we implement `Drop` !! 369 //! // before, instead we implement it here and delegate to `PinnedDrop`.
390 //! impl ::core::ops::Drop for Foo { 370 //! impl ::core::ops::Drop for Foo {
391 //! fn drop(&mut self) { 371 //! fn drop(&mut self) {
392 //! // Since we are getting droppe 372 //! // Since we are getting dropped, no one else has a reference to `self` and thus we
393 //! // can assume that we never mo 373 //! // can assume that we never move.
394 //! let pinned = unsafe { ::core:: 374 //! let pinned = unsafe { ::core::pin::Pin::new_unchecked(self) };
395 //! // Create the unsafe token tha 375 //! // Create the unsafe token that proves that we are inside of a destructor, this
396 //! // type is only allowed to be 376 //! // type is only allowed to be created in a destructor.
397 //! let token = unsafe { ::kernel: 377 //! let token = unsafe { ::kernel::init::__internal::OnlyCallFromDrop::new() };
398 //! ::kernel::init::PinnedDrop::dr 378 //! ::kernel::init::PinnedDrop::drop(pinned, token);
399 //! } 379 //! }
400 //! } 380 //! }
401 //! }; 381 //! };
402 //! ``` 382 //! ```
403 //! 383 //!
404 //! ## `#[pinned_drop]` on `impl PinnedDrop fo 384 //! ## `#[pinned_drop]` on `impl PinnedDrop for Foo`
405 //! 385 //!
406 //! This macro is used to implement the `Pinne 386 //! This macro is used to implement the `PinnedDrop` trait, since that trait is `unsafe` and has an
407 //! extra parameter that should not be used at 387 //! extra parameter that should not be used at all. The macro hides that parameter.
408 //! 388 //!
409 //! Here is the `PinnedDrop` impl for `Foo`: 389 //! Here is the `PinnedDrop` impl for `Foo`:
410 //! 390 //!
411 //! ```rust,ignore !! 391 //! ```rust
412 //! #[pinned_drop] 392 //! #[pinned_drop]
413 //! impl PinnedDrop for Foo { 393 //! impl PinnedDrop for Foo {
414 //! fn drop(self: Pin<&mut Self>) { 394 //! fn drop(self: Pin<&mut Self>) {
415 //! pr_info!("{self:p} is getting drop !! 395 //! println!("{self:p} is getting dropped.");
416 //! } 396 //! }
417 //! } 397 //! }
418 //! ``` 398 //! ```
419 //! 399 //!
420 //! This expands to the following code: 400 //! This expands to the following code:
421 //! 401 //!
422 //! ```rust,ignore !! 402 //! ```rust
423 //! // `unsafe`, full path and the token param 403 //! // `unsafe`, full path and the token parameter are added, everything else stays the same.
424 //! unsafe impl ::kernel::init::PinnedDrop for 404 //! unsafe impl ::kernel::init::PinnedDrop for Foo {
425 //! fn drop(self: Pin<&mut Self>, _: ::ker 405 //! fn drop(self: Pin<&mut Self>, _: ::kernel::init::__internal::OnlyCallFromDrop) {
426 //! pr_info!("{self:p} is getting drop !! 406 //! println!("{self:p} is getting dropped.");
427 //! } 407 //! }
428 //! } 408 //! }
429 //! ``` 409 //! ```
430 //! 410 //!
431 //! ## `pin_init!` on `Foo` 411 //! ## `pin_init!` on `Foo`
432 //! 412 //!
433 //! Since we already took a look at `pin_init! !! 413 //! Since we already took a look at `pin_init!` on `Bar`, this section will only explain the
434 //! of `pin_init!` on `Foo`: !! 414 //! differences/new things in the expansion of `pin_init!` on `Foo`:
435 //! 415 //!
436 //! ```rust,ignore !! 416 //! ```rust
437 //! let a = 42; 417 //! let a = 42;
438 //! let initializer = pin_init!(Foo { 418 //! let initializer = pin_init!(Foo {
439 //! a, 419 //! a,
440 //! b <- Bar::new(36), 420 //! b <- Bar::new(36),
441 //! }); 421 //! });
442 //! ``` 422 //! ```
443 //! 423 //!
444 //! This expands to the following code: 424 //! This expands to the following code:
445 //! 425 //!
446 //! ```rust,ignore !! 426 //! ```rust
447 //! let a = 42; 427 //! let a = 42;
448 //! let initializer = { 428 //! let initializer = {
449 //! struct __InitOk; 429 //! struct __InitOk;
450 //! let data = unsafe { 430 //! let data = unsafe {
451 //! use ::kernel::init::__internal::Ha 431 //! use ::kernel::init::__internal::HasPinData;
452 //! Foo::__pin_data() 432 //! Foo::__pin_data()
453 //! }; 433 //! };
454 //! let init = ::kernel::init::__internal: 434 //! let init = ::kernel::init::__internal::PinData::make_closure::<
455 //! _, 435 //! _,
456 //! __InitOk, 436 //! __InitOk,
457 //! ::core::convert::Infallible, 437 //! ::core::convert::Infallible,
458 //! >(data, move |slot| { 438 //! >(data, move |slot| {
459 //! { 439 //! {
460 //! struct __InitOk; 440 //! struct __InitOk;
461 //! { !! 441 //! unsafe { ::core::ptr::write(&raw mut (*slot).a, a) };
462 //! unsafe { ::core::ptr::writ !! 442 //! let a = &unsafe { ::kernel::init::__internal::DropGuard::new(&raw mut (*slot).a) };
463 //! } !! 443 //! let b = Bar::new(36);
464 //! let __a_guard = unsafe { !! 444 //! // Here we use `data` to access the correct field and require that `b` is of type
465 //! ::kernel::init::__internal !! 445 //! // `PinInit<Bar<u32>, Infallible>`.
466 //! }; !! 446 //! unsafe { data.b(&raw mut (*slot).b, b)? };
467 //! let init = Bar::new(36); !! 447 //! let b = &unsafe { ::kernel::init::__internal::DropGuard::new(&raw mut (*slot).b) };
468 //! unsafe { data.b(::core::addr_o !! 448 //!
469 //! let __b_guard = unsafe { <<
470 //! ::kernel::init::__internal <<
471 //! }; <<
472 //! ::core::mem::forget(__b_guard) <<
473 //! ::core::mem::forget(__a_guard) <<
474 //! #[allow(unreachable_code, clip 449 //! #[allow(unreachable_code, clippy::diverging_sub_expression)]
475 //! let _ = || { !! 450 //! if false {
476 //! unsafe { 451 //! unsafe {
477 //! ::core::ptr::write( 452 //! ::core::ptr::write(
478 //! slot, 453 //! slot,
479 //! Foo { 454 //! Foo {
480 //! a: ::core::pan 455 //! a: ::core::panic!(),
481 //! b: ::core::pan 456 //! b: ::core::panic!(),
482 //! }, 457 //! },
483 //! ); 458 //! );
484 //! }; 459 //! };
485 //! }; !! 460 //! }
>> 461 //! unsafe { ::kernel::init::__internal::DropGuard::forget(a) };
>> 462 //! unsafe { ::kernel::init::__internal::DropGuard::forget(b) };
486 //! } 463 //! }
487 //! Ok(__InitOk) 464 //! Ok(__InitOk)
488 //! }); 465 //! });
489 //! let init = move | !! 466 //! let init = move |slot| -> ::core::result::Result<(), ::core::convert::Infallible> {
490 //! slot, <<
491 //! | -> ::core::result::Result<(), ::core <<
492 //! init(slot).map(|__InitOk| ()) 467 //! init(slot).map(|__InitOk| ())
493 //! }; 468 //! };
494 //! let init = unsafe { 469 //! let init = unsafe {
495 //! ::kernel::init::pin_init_from_clos 470 //! ::kernel::init::pin_init_from_closure::<_, ::core::convert::Infallible>(init)
496 //! }; 471 //! };
497 //! init 472 //! init
498 //! }; 473 //! };
499 //! ``` 474 //! ```
500 475
501 /// Creates a `unsafe impl<...> PinnedDrop for 476 /// Creates a `unsafe impl<...> PinnedDrop for $type` block.
502 /// 477 ///
503 /// See [`PinnedDrop`] for more information. 478 /// See [`PinnedDrop`] for more information.
504 #[doc(hidden)] 479 #[doc(hidden)]
505 #[macro_export] 480 #[macro_export]
506 macro_rules! __pinned_drop { 481 macro_rules! __pinned_drop {
507 ( 482 (
508 @impl_sig($($impl_sig:tt)*), 483 @impl_sig($($impl_sig:tt)*),
509 @impl_body( 484 @impl_body(
510 $(#[$($attr:tt)*])* 485 $(#[$($attr:tt)*])*
511 fn drop($($sig:tt)*) { 486 fn drop($($sig:tt)*) {
512 $($inner:tt)* 487 $($inner:tt)*
513 } 488 }
514 ), 489 ),
515 ) => { 490 ) => {
516 unsafe $($impl_sig)* { 491 unsafe $($impl_sig)* {
517 // Inherit all attributes and the 492 // Inherit all attributes and the type/ident tokens for the signature.
518 $(#[$($attr)*])* 493 $(#[$($attr)*])*
519 fn drop($($sig)*, _: $crate::init: 494 fn drop($($sig)*, _: $crate::init::__internal::OnlyCallFromDrop) {
520 $($inner)* 495 $($inner)*
521 } 496 }
522 } 497 }
523 } 498 }
524 } 499 }
525 500
526 /// This macro first parses the struct definit 501 /// This macro first parses the struct definition such that it separates pinned and not pinned
527 /// fields. Afterwards it declares the struct 502 /// fields. Afterwards it declares the struct and implement the `PinData` trait safely.
528 #[doc(hidden)] 503 #[doc(hidden)]
529 #[macro_export] 504 #[macro_export]
530 macro_rules! __pin_data { 505 macro_rules! __pin_data {
531 // Proc-macro entry point, this is supplie 506 // Proc-macro entry point, this is supplied by the proc-macro pre-parsing.
532 (parse_input: 507 (parse_input:
533 @args($($pinned_drop:ident)?), 508 @args($($pinned_drop:ident)?),
534 @sig( 509 @sig(
535 $(#[$($struct_attr:tt)*])* 510 $(#[$($struct_attr:tt)*])*
536 $vis:vis struct $name:ident 511 $vis:vis struct $name:ident
537 $(where $($whr:tt)*)? 512 $(where $($whr:tt)*)?
538 ), 513 ),
539 @impl_generics($($impl_generics:tt)*), 514 @impl_generics($($impl_generics:tt)*),
540 @ty_generics($($ty_generics:tt)*), 515 @ty_generics($($ty_generics:tt)*),
541 @decl_generics($($decl_generics:tt)*), <<
542 @body({ $($fields:tt)* }), 516 @body({ $($fields:tt)* }),
543 ) => { 517 ) => {
544 // We now use token munching to iterat 518 // We now use token munching to iterate through all of the fields. While doing this we
545 // identify fields marked with `#[pin] 519 // identify fields marked with `#[pin]`, these fields are the 'pinned fields'. The user
546 // wants these to be structurally pinn 520 // wants these to be structurally pinned. The rest of the fields are the
547 // 'not pinned fields'. Additionally w 521 // 'not pinned fields'. Additionally we collect all fields, since we need them in the right
548 // order to declare the struct. 522 // order to declare the struct.
549 // 523 //
550 // In this call we also put some expla 524 // In this call we also put some explaining comments for the parameters.
551 $crate::__pin_data!(find_pinned_fields 525 $crate::__pin_data!(find_pinned_fields:
552 // Attributes on the struct itself 526 // Attributes on the struct itself, these will just be propagated to be put onto the
553 // struct definition. 527 // struct definition.
554 @struct_attrs($(#[$($struct_attr)* 528 @struct_attrs($(#[$($struct_attr)*])*),
555 // The visibility of the struct. 529 // The visibility of the struct.
556 @vis($vis), 530 @vis($vis),
557 // The name of the struct. 531 // The name of the struct.
558 @name($name), 532 @name($name),
559 // The 'impl generics', the generi 533 // The 'impl generics', the generics that will need to be specified on the struct inside
560 // of an `impl<$ty_generics>` bloc 534 // of an `impl<$ty_generics>` block.
561 @impl_generics($($impl_generics)*) 535 @impl_generics($($impl_generics)*),
562 // The 'ty generics', the generics 536 // The 'ty generics', the generics that will need to be specified on the impl blocks.
563 @ty_generics($($ty_generics)*), 537 @ty_generics($($ty_generics)*),
564 // The 'decl generics', the generi <<
565 // definition. <<
566 @decl_generics($($decl_generics)*) <<
567 // The where clause of any impl bl 538 // The where clause of any impl block and the declaration.
568 @where($($($whr)*)?), 539 @where($($($whr)*)?),
569 // The remaining fields tokens tha 540 // The remaining fields tokens that need to be processed.
570 // We add a `,` at the end to ensu 541 // We add a `,` at the end to ensure correct parsing.
571 @fields_munch($($fields)* ,), 542 @fields_munch($($fields)* ,),
572 // The pinned fields. 543 // The pinned fields.
573 @pinned(), 544 @pinned(),
574 // The not pinned fields. 545 // The not pinned fields.
575 @not_pinned(), 546 @not_pinned(),
576 // All fields. 547 // All fields.
577 @fields(), 548 @fields(),
578 // The accumulator containing all 549 // The accumulator containing all attributes already parsed.
579 @accum(), 550 @accum(),
580 // Contains `yes` or `` to indicat 551 // Contains `yes` or `` to indicate if `#[pin]` was found on the current field.
581 @is_pinned(), 552 @is_pinned(),
582 // The proc-macro argument, this s 553 // The proc-macro argument, this should be `PinnedDrop` or ``.
583 @pinned_drop($($pinned_drop)?), 554 @pinned_drop($($pinned_drop)?),
584 ); 555 );
585 }; 556 };
586 (find_pinned_fields: 557 (find_pinned_fields:
587 @struct_attrs($($struct_attrs:tt)*), 558 @struct_attrs($($struct_attrs:tt)*),
588 @vis($vis:vis), 559 @vis($vis:vis),
589 @name($name:ident), 560 @name($name:ident),
590 @impl_generics($($impl_generics:tt)*), 561 @impl_generics($($impl_generics:tt)*),
591 @ty_generics($($ty_generics:tt)*), 562 @ty_generics($($ty_generics:tt)*),
592 @decl_generics($($decl_generics:tt)*), <<
593 @where($($whr:tt)*), 563 @where($($whr:tt)*),
594 // We found a PhantomPinned field, thi 564 // We found a PhantomPinned field, this should generally be pinned!
595 @fields_munch($field:ident : $($($(::) 565 @fields_munch($field:ident : $($($(::)?core::)?marker::)?PhantomPinned, $($rest:tt)*),
596 @pinned($($pinned:tt)*), 566 @pinned($($pinned:tt)*),
597 @not_pinned($($not_pinned:tt)*), 567 @not_pinned($($not_pinned:tt)*),
598 @fields($($fields:tt)*), 568 @fields($($fields:tt)*),
599 @accum($($accum:tt)*), 569 @accum($($accum:tt)*),
600 // This field is not pinned. 570 // This field is not pinned.
601 @is_pinned(), 571 @is_pinned(),
602 @pinned_drop($($pinned_drop:ident)?), 572 @pinned_drop($($pinned_drop:ident)?),
603 ) => { 573 ) => {
604 ::core::compile_error!(concat!( 574 ::core::compile_error!(concat!(
605 "The field `", 575 "The field `",
606 stringify!($field), 576 stringify!($field),
607 "` of type `PhantomPinned` only ha 577 "` of type `PhantomPinned` only has an effect, if it has the `#[pin]` attribute.",
608 )); 578 ));
609 $crate::__pin_data!(find_pinned_fields 579 $crate::__pin_data!(find_pinned_fields:
610 @struct_attrs($($struct_attrs)*), 580 @struct_attrs($($struct_attrs)*),
611 @vis($vis), 581 @vis($vis),
612 @name($name), 582 @name($name),
613 @impl_generics($($impl_generics)*) 583 @impl_generics($($impl_generics)*),
614 @ty_generics($($ty_generics)*), 584 @ty_generics($($ty_generics)*),
615 @decl_generics($($decl_generics)*) <<
616 @where($($whr)*), 585 @where($($whr)*),
617 @fields_munch($($rest)*), 586 @fields_munch($($rest)*),
618 @pinned($($pinned)* $($accum)* $fi 587 @pinned($($pinned)* $($accum)* $field: ::core::marker::PhantomPinned,),
619 @not_pinned($($not_pinned)*), 588 @not_pinned($($not_pinned)*),
620 @fields($($fields)* $($accum)* $fi 589 @fields($($fields)* $($accum)* $field: ::core::marker::PhantomPinned,),
621 @accum(), 590 @accum(),
622 @is_pinned(), 591 @is_pinned(),
623 @pinned_drop($($pinned_drop)?), 592 @pinned_drop($($pinned_drop)?),
624 ); 593 );
625 }; 594 };
626 (find_pinned_fields: 595 (find_pinned_fields:
627 @struct_attrs($($struct_attrs:tt)*), 596 @struct_attrs($($struct_attrs:tt)*),
628 @vis($vis:vis), 597 @vis($vis:vis),
629 @name($name:ident), 598 @name($name:ident),
630 @impl_generics($($impl_generics:tt)*), 599 @impl_generics($($impl_generics:tt)*),
631 @ty_generics($($ty_generics:tt)*), 600 @ty_generics($($ty_generics:tt)*),
632 @decl_generics($($decl_generics:tt)*), <<
633 @where($($whr:tt)*), 601 @where($($whr:tt)*),
634 // We reached the field declaration. 602 // We reached the field declaration.
635 @fields_munch($field:ident : $type:ty, 603 @fields_munch($field:ident : $type:ty, $($rest:tt)*),
636 @pinned($($pinned:tt)*), 604 @pinned($($pinned:tt)*),
637 @not_pinned($($not_pinned:tt)*), 605 @not_pinned($($not_pinned:tt)*),
638 @fields($($fields:tt)*), 606 @fields($($fields:tt)*),
639 @accum($($accum:tt)*), 607 @accum($($accum:tt)*),
640 // This field is pinned. 608 // This field is pinned.
641 @is_pinned(yes), 609 @is_pinned(yes),
642 @pinned_drop($($pinned_drop:ident)?), 610 @pinned_drop($($pinned_drop:ident)?),
643 ) => { 611 ) => {
644 $crate::__pin_data!(find_pinned_fields 612 $crate::__pin_data!(find_pinned_fields:
645 @struct_attrs($($struct_attrs)*), 613 @struct_attrs($($struct_attrs)*),
646 @vis($vis), 614 @vis($vis),
647 @name($name), 615 @name($name),
648 @impl_generics($($impl_generics)*) 616 @impl_generics($($impl_generics)*),
649 @ty_generics($($ty_generics)*), 617 @ty_generics($($ty_generics)*),
650 @decl_generics($($decl_generics)*) <<
651 @where($($whr)*), 618 @where($($whr)*),
652 @fields_munch($($rest)*), 619 @fields_munch($($rest)*),
653 @pinned($($pinned)* $($accum)* $fi 620 @pinned($($pinned)* $($accum)* $field: $type,),
654 @not_pinned($($not_pinned)*), 621 @not_pinned($($not_pinned)*),
655 @fields($($fields)* $($accum)* $fi 622 @fields($($fields)* $($accum)* $field: $type,),
656 @accum(), 623 @accum(),
657 @is_pinned(), 624 @is_pinned(),
658 @pinned_drop($($pinned_drop)?), 625 @pinned_drop($($pinned_drop)?),
659 ); 626 );
660 }; 627 };
661 (find_pinned_fields: 628 (find_pinned_fields:
662 @struct_attrs($($struct_attrs:tt)*), 629 @struct_attrs($($struct_attrs:tt)*),
663 @vis($vis:vis), 630 @vis($vis:vis),
664 @name($name:ident), 631 @name($name:ident),
665 @impl_generics($($impl_generics:tt)*), 632 @impl_generics($($impl_generics:tt)*),
666 @ty_generics($($ty_generics:tt)*), 633 @ty_generics($($ty_generics:tt)*),
667 @decl_generics($($decl_generics:tt)*), <<
668 @where($($whr:tt)*), 634 @where($($whr:tt)*),
669 // We reached the field declaration. 635 // We reached the field declaration.
670 @fields_munch($field:ident : $type:ty, 636 @fields_munch($field:ident : $type:ty, $($rest:tt)*),
671 @pinned($($pinned:tt)*), 637 @pinned($($pinned:tt)*),
672 @not_pinned($($not_pinned:tt)*), 638 @not_pinned($($not_pinned:tt)*),
673 @fields($($fields:tt)*), 639 @fields($($fields:tt)*),
674 @accum($($accum:tt)*), 640 @accum($($accum:tt)*),
675 // This field is not pinned. 641 // This field is not pinned.
676 @is_pinned(), 642 @is_pinned(),
677 @pinned_drop($($pinned_drop:ident)?), 643 @pinned_drop($($pinned_drop:ident)?),
678 ) => { 644 ) => {
679 $crate::__pin_data!(find_pinned_fields 645 $crate::__pin_data!(find_pinned_fields:
680 @struct_attrs($($struct_attrs)*), 646 @struct_attrs($($struct_attrs)*),
681 @vis($vis), 647 @vis($vis),
682 @name($name), 648 @name($name),
683 @impl_generics($($impl_generics)*) 649 @impl_generics($($impl_generics)*),
684 @ty_generics($($ty_generics)*), 650 @ty_generics($($ty_generics)*),
685 @decl_generics($($decl_generics)*) <<
686 @where($($whr)*), 651 @where($($whr)*),
687 @fields_munch($($rest)*), 652 @fields_munch($($rest)*),
688 @pinned($($pinned)*), 653 @pinned($($pinned)*),
689 @not_pinned($($not_pinned)* $($acc 654 @not_pinned($($not_pinned)* $($accum)* $field: $type,),
690 @fields($($fields)* $($accum)* $fi 655 @fields($($fields)* $($accum)* $field: $type,),
691 @accum(), 656 @accum(),
692 @is_pinned(), 657 @is_pinned(),
693 @pinned_drop($($pinned_drop)?), 658 @pinned_drop($($pinned_drop)?),
694 ); 659 );
695 }; 660 };
696 (find_pinned_fields: 661 (find_pinned_fields:
697 @struct_attrs($($struct_attrs:tt)*), 662 @struct_attrs($($struct_attrs:tt)*),
698 @vis($vis:vis), 663 @vis($vis:vis),
699 @name($name:ident), 664 @name($name:ident),
700 @impl_generics($($impl_generics:tt)*), 665 @impl_generics($($impl_generics:tt)*),
701 @ty_generics($($ty_generics:tt)*), 666 @ty_generics($($ty_generics:tt)*),
702 @decl_generics($($decl_generics:tt)*), <<
703 @where($($whr:tt)*), 667 @where($($whr:tt)*),
704 // We found the `#[pin]` attr. 668 // We found the `#[pin]` attr.
705 @fields_munch(#[pin] $($rest:tt)*), 669 @fields_munch(#[pin] $($rest:tt)*),
706 @pinned($($pinned:tt)*), 670 @pinned($($pinned:tt)*),
707 @not_pinned($($not_pinned:tt)*), 671 @not_pinned($($not_pinned:tt)*),
708 @fields($($fields:tt)*), 672 @fields($($fields:tt)*),
709 @accum($($accum:tt)*), 673 @accum($($accum:tt)*),
710 @is_pinned($($is_pinned:ident)?), 674 @is_pinned($($is_pinned:ident)?),
711 @pinned_drop($($pinned_drop:ident)?), 675 @pinned_drop($($pinned_drop:ident)?),
712 ) => { 676 ) => {
713 $crate::__pin_data!(find_pinned_fields 677 $crate::__pin_data!(find_pinned_fields:
714 @struct_attrs($($struct_attrs)*), 678 @struct_attrs($($struct_attrs)*),
715 @vis($vis), 679 @vis($vis),
716 @name($name), 680 @name($name),
717 @impl_generics($($impl_generics)*) 681 @impl_generics($($impl_generics)*),
718 @ty_generics($($ty_generics)*), 682 @ty_generics($($ty_generics)*),
719 @decl_generics($($decl_generics)*) <<
720 @where($($whr)*), 683 @where($($whr)*),
721 @fields_munch($($rest)*), 684 @fields_munch($($rest)*),
722 // We do not include `#[pin]` in t 685 // We do not include `#[pin]` in the list of attributes, since it is not actually an
723 // attribute that is defined somew 686 // attribute that is defined somewhere.
724 @pinned($($pinned)*), 687 @pinned($($pinned)*),
725 @not_pinned($($not_pinned)*), 688 @not_pinned($($not_pinned)*),
726 @fields($($fields)*), 689 @fields($($fields)*),
727 @accum($($accum)*), 690 @accum($($accum)*),
728 // Set this to `yes`. 691 // Set this to `yes`.
729 @is_pinned(yes), 692 @is_pinned(yes),
730 @pinned_drop($($pinned_drop)?), 693 @pinned_drop($($pinned_drop)?),
731 ); 694 );
732 }; 695 };
733 (find_pinned_fields: 696 (find_pinned_fields:
734 @struct_attrs($($struct_attrs:tt)*), 697 @struct_attrs($($struct_attrs:tt)*),
735 @vis($vis:vis), 698 @vis($vis:vis),
736 @name($name:ident), 699 @name($name:ident),
737 @impl_generics($($impl_generics:tt)*), 700 @impl_generics($($impl_generics:tt)*),
738 @ty_generics($($ty_generics:tt)*), 701 @ty_generics($($ty_generics:tt)*),
739 @decl_generics($($decl_generics:tt)*), <<
740 @where($($whr:tt)*), 702 @where($($whr:tt)*),
741 // We reached the field declaration wi 703 // We reached the field declaration with visibility, for simplicity we only munch the
742 // visibility and put it into `$accum` 704 // visibility and put it into `$accum`.
743 @fields_munch($fvis:vis $field:ident $ 705 @fields_munch($fvis:vis $field:ident $($rest:tt)*),
744 @pinned($($pinned:tt)*), 706 @pinned($($pinned:tt)*),
745 @not_pinned($($not_pinned:tt)*), 707 @not_pinned($($not_pinned:tt)*),
746 @fields($($fields:tt)*), 708 @fields($($fields:tt)*),
747 @accum($($accum:tt)*), 709 @accum($($accum:tt)*),
748 @is_pinned($($is_pinned:ident)?), 710 @is_pinned($($is_pinned:ident)?),
749 @pinned_drop($($pinned_drop:ident)?), 711 @pinned_drop($($pinned_drop:ident)?),
750 ) => { 712 ) => {
751 $crate::__pin_data!(find_pinned_fields 713 $crate::__pin_data!(find_pinned_fields:
752 @struct_attrs($($struct_attrs)*), 714 @struct_attrs($($struct_attrs)*),
753 @vis($vis), 715 @vis($vis),
754 @name($name), 716 @name($name),
755 @impl_generics($($impl_generics)*) 717 @impl_generics($($impl_generics)*),
756 @ty_generics($($ty_generics)*), 718 @ty_generics($($ty_generics)*),
757 @decl_generics($($decl_generics)*) <<
758 @where($($whr)*), 719 @where($($whr)*),
759 @fields_munch($field $($rest)*), 720 @fields_munch($field $($rest)*),
760 @pinned($($pinned)*), 721 @pinned($($pinned)*),
761 @not_pinned($($not_pinned)*), 722 @not_pinned($($not_pinned)*),
762 @fields($($fields)*), 723 @fields($($fields)*),
763 @accum($($accum)* $fvis), 724 @accum($($accum)* $fvis),
764 @is_pinned($($is_pinned)?), 725 @is_pinned($($is_pinned)?),
765 @pinned_drop($($pinned_drop)?), 726 @pinned_drop($($pinned_drop)?),
766 ); 727 );
767 }; 728 };
768 (find_pinned_fields: 729 (find_pinned_fields:
769 @struct_attrs($($struct_attrs:tt)*), 730 @struct_attrs($($struct_attrs:tt)*),
770 @vis($vis:vis), 731 @vis($vis:vis),
771 @name($name:ident), 732 @name($name:ident),
772 @impl_generics($($impl_generics:tt)*), 733 @impl_generics($($impl_generics:tt)*),
773 @ty_generics($($ty_generics:tt)*), 734 @ty_generics($($ty_generics:tt)*),
774 @decl_generics($($decl_generics:tt)*), <<
775 @where($($whr:tt)*), 735 @where($($whr:tt)*),
776 // Some other attribute, just put it i 736 // Some other attribute, just put it into `$accum`.
777 @fields_munch(#[$($attr:tt)*] $($rest: 737 @fields_munch(#[$($attr:tt)*] $($rest:tt)*),
778 @pinned($($pinned:tt)*), 738 @pinned($($pinned:tt)*),
779 @not_pinned($($not_pinned:tt)*), 739 @not_pinned($($not_pinned:tt)*),
780 @fields($($fields:tt)*), 740 @fields($($fields:tt)*),
781 @accum($($accum:tt)*), 741 @accum($($accum:tt)*),
782 @is_pinned($($is_pinned:ident)?), 742 @is_pinned($($is_pinned:ident)?),
783 @pinned_drop($($pinned_drop:ident)?), 743 @pinned_drop($($pinned_drop:ident)?),
784 ) => { 744 ) => {
785 $crate::__pin_data!(find_pinned_fields 745 $crate::__pin_data!(find_pinned_fields:
786 @struct_attrs($($struct_attrs)*), 746 @struct_attrs($($struct_attrs)*),
787 @vis($vis), 747 @vis($vis),
788 @name($name), 748 @name($name),
789 @impl_generics($($impl_generics)*) 749 @impl_generics($($impl_generics)*),
790 @ty_generics($($ty_generics)*), 750 @ty_generics($($ty_generics)*),
791 @decl_generics($($decl_generics)*) <<
792 @where($($whr)*), 751 @where($($whr)*),
793 @fields_munch($($rest)*), 752 @fields_munch($($rest)*),
794 @pinned($($pinned)*), 753 @pinned($($pinned)*),
795 @not_pinned($($not_pinned)*), 754 @not_pinned($($not_pinned)*),
796 @fields($($fields)*), 755 @fields($($fields)*),
797 @accum($($accum)* #[$($attr)*]), 756 @accum($($accum)* #[$($attr)*]),
798 @is_pinned($($is_pinned)?), 757 @is_pinned($($is_pinned)?),
799 @pinned_drop($($pinned_drop)?), 758 @pinned_drop($($pinned_drop)?),
800 ); 759 );
801 }; 760 };
802 (find_pinned_fields: 761 (find_pinned_fields:
803 @struct_attrs($($struct_attrs:tt)*), 762 @struct_attrs($($struct_attrs:tt)*),
804 @vis($vis:vis), 763 @vis($vis:vis),
805 @name($name:ident), 764 @name($name:ident),
806 @impl_generics($($impl_generics:tt)*), 765 @impl_generics($($impl_generics:tt)*),
807 @ty_generics($($ty_generics:tt)*), 766 @ty_generics($($ty_generics:tt)*),
808 @decl_generics($($decl_generics:tt)*), <<
809 @where($($whr:tt)*), 767 @where($($whr:tt)*),
810 // We reached the end of the fields, p 768 // We reached the end of the fields, plus an optional additional comma, since we added one
811 // before and the user is also allowed 769 // before and the user is also allowed to put a trailing comma.
812 @fields_munch($(,)?), 770 @fields_munch($(,)?),
813 @pinned($($pinned:tt)*), 771 @pinned($($pinned:tt)*),
814 @not_pinned($($not_pinned:tt)*), 772 @not_pinned($($not_pinned:tt)*),
815 @fields($($fields:tt)*), 773 @fields($($fields:tt)*),
816 @accum(), 774 @accum(),
817 @is_pinned(), 775 @is_pinned(),
818 @pinned_drop($($pinned_drop:ident)?), 776 @pinned_drop($($pinned_drop:ident)?),
819 ) => { 777 ) => {
820 // Declare the struct with all fields 778 // Declare the struct with all fields in the correct order.
821 $($struct_attrs)* 779 $($struct_attrs)*
822 $vis struct $name <$($decl_generics)*> !! 780 $vis struct $name <$($impl_generics)*>
823 where $($whr)* 781 where $($whr)*
824 { 782 {
825 $($fields)* 783 $($fields)*
826 } 784 }
827 785
828 // We put the rest into this const ite 786 // We put the rest into this const item, because it then will not be accessible to anything
829 // outside. 787 // outside.
830 const _: () = { 788 const _: () = {
831 // We declare this struct which wi 789 // We declare this struct which will host all of the projection function for our type.
832 // it will be invariant over all g 790 // it will be invariant over all generic parameters which are inherited from the
833 // struct. 791 // struct.
834 $vis struct __ThePinData<$($impl_g 792 $vis struct __ThePinData<$($impl_generics)*>
835 where $($whr)* 793 where $($whr)*
836 { 794 {
837 __phantom: ::core::marker::Pha 795 __phantom: ::core::marker::PhantomData<
838 fn($name<$($ty_generics)*> 796 fn($name<$($ty_generics)*>) -> $name<$($ty_generics)*>
839 >, 797 >,
840 } 798 }
841 799
842 impl<$($impl_generics)*> ::core::c 800 impl<$($impl_generics)*> ::core::clone::Clone for __ThePinData<$($ty_generics)*>
843 where $($whr)* 801 where $($whr)*
844 { 802 {
845 fn clone(&self) -> Self { *sel 803 fn clone(&self) -> Self { *self }
846 } 804 }
847 805
848 impl<$($impl_generics)*> ::core::m 806 impl<$($impl_generics)*> ::core::marker::Copy for __ThePinData<$($ty_generics)*>
849 where $($whr)* 807 where $($whr)*
850 {} 808 {}
851 809
852 // Make all projection functions. 810 // Make all projection functions.
853 $crate::__pin_data!(make_pin_data: 811 $crate::__pin_data!(make_pin_data:
854 @pin_data(__ThePinData), 812 @pin_data(__ThePinData),
855 @impl_generics($($impl_generic 813 @impl_generics($($impl_generics)*),
856 @ty_generics($($ty_generics)*) 814 @ty_generics($($ty_generics)*),
857 @where($($whr)*), 815 @where($($whr)*),
858 @pinned($($pinned)*), 816 @pinned($($pinned)*),
859 @not_pinned($($not_pinned)*), 817 @not_pinned($($not_pinned)*),
860 ); 818 );
861 819
862 // SAFETY: We have added the corre 820 // SAFETY: We have added the correct projection functions above to `__ThePinData` and
863 // we also use the least restricti 821 // we also use the least restrictive generics possible.
864 unsafe impl<$($impl_generics)*> 822 unsafe impl<$($impl_generics)*>
865 $crate::init::__internal::HasP 823 $crate::init::__internal::HasPinData for $name<$($ty_generics)*>
866 where $($whr)* 824 where $($whr)*
867 { 825 {
868 type PinData = __ThePinData<$( 826 type PinData = __ThePinData<$($ty_generics)*>;
869 827
870 unsafe fn __pin_data() -> Self 828 unsafe fn __pin_data() -> Self::PinData {
871 __ThePinData { __phantom: 829 __ThePinData { __phantom: ::core::marker::PhantomData }
872 } 830 }
873 } 831 }
874 832
875 unsafe impl<$($impl_generics)*> 833 unsafe impl<$($impl_generics)*>
876 $crate::init::__internal::PinD 834 $crate::init::__internal::PinData for __ThePinData<$($ty_generics)*>
877 where $($whr)* 835 where $($whr)*
878 { 836 {
879 type Datee = $name<$($ty_gener 837 type Datee = $name<$($ty_generics)*>;
880 } 838 }
881 839
882 // This struct will be used for th 840 // This struct will be used for the unpin analysis. Since only structurally pinned
883 // fields are relevant whether the 841 // fields are relevant whether the struct should implement `Unpin`.
884 #[allow(dead_code)] 842 #[allow(dead_code)]
885 struct __Unpin <'__pin, $($impl_ge 843 struct __Unpin <'__pin, $($impl_generics)*>
886 where $($whr)* 844 where $($whr)*
887 { 845 {
888 __phantom_pin: ::core::marker: 846 __phantom_pin: ::core::marker::PhantomData<fn(&'__pin ()) -> &'__pin ()>,
889 __phantom: ::core::marker::Pha 847 __phantom: ::core::marker::PhantomData<
890 fn($name<$($ty_generics)*> 848 fn($name<$($ty_generics)*>) -> $name<$($ty_generics)*>
891 >, 849 >,
892 // Only the pinned fields. 850 // Only the pinned fields.
893 $($pinned)* 851 $($pinned)*
894 } 852 }
895 853
896 #[doc(hidden)] 854 #[doc(hidden)]
897 impl<'__pin, $($impl_generics)*> : 855 impl<'__pin, $($impl_generics)*> ::core::marker::Unpin for $name<$($ty_generics)*>
898 where 856 where
899 __Unpin<'__pin, $($ty_generics 857 __Unpin<'__pin, $($ty_generics)*>: ::core::marker::Unpin,
900 $($whr)* 858 $($whr)*
901 {} 859 {}
902 860
903 // We need to disallow normal `Dro 861 // We need to disallow normal `Drop` implementation, the exact behavior depends on
904 // whether `PinnedDrop` was specif 862 // whether `PinnedDrop` was specified as the parameter.
905 $crate::__pin_data!(drop_preventio 863 $crate::__pin_data!(drop_prevention:
906 @name($name), 864 @name($name),
907 @impl_generics($($impl_generic 865 @impl_generics($($impl_generics)*),
908 @ty_generics($($ty_generics)*) 866 @ty_generics($($ty_generics)*),
909 @where($($whr)*), 867 @where($($whr)*),
910 @pinned_drop($($pinned_drop)?) 868 @pinned_drop($($pinned_drop)?),
911 ); 869 );
912 }; 870 };
913 }; 871 };
914 // When no `PinnedDrop` was specified, the 872 // When no `PinnedDrop` was specified, then we have to prevent implementing drop.
915 (drop_prevention: 873 (drop_prevention:
916 @name($name:ident), 874 @name($name:ident),
917 @impl_generics($($impl_generics:tt)*), 875 @impl_generics($($impl_generics:tt)*),
918 @ty_generics($($ty_generics:tt)*), 876 @ty_generics($($ty_generics:tt)*),
919 @where($($whr:tt)*), 877 @where($($whr:tt)*),
920 @pinned_drop(), 878 @pinned_drop(),
921 ) => { 879 ) => {
922 // We prevent this by creating a trait 880 // We prevent this by creating a trait that will be implemented for all types implementing
923 // `Drop`. Additionally we will implem 881 // `Drop`. Additionally we will implement this trait for the struct leading to a conflict,
924 // if it also implements `Drop` 882 // if it also implements `Drop`
925 trait MustNotImplDrop {} 883 trait MustNotImplDrop {}
926 #[allow(drop_bounds)] 884 #[allow(drop_bounds)]
927 impl<T: ::core::ops::Drop> MustNotImpl 885 impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
928 impl<$($impl_generics)*> MustNotImplDr 886 impl<$($impl_generics)*> MustNotImplDrop for $name<$($ty_generics)*>
929 where $($whr)* {} 887 where $($whr)* {}
930 // We also take care to prevent users 888 // We also take care to prevent users from writing a useless `PinnedDrop` implementation.
931 // They might implement `PinnedDrop` c 889 // They might implement `PinnedDrop` correctly for the struct, but forget to give
932 // `PinnedDrop` as the parameter to `# 890 // `PinnedDrop` as the parameter to `#[pin_data]`.
933 #[allow(non_camel_case_types)] 891 #[allow(non_camel_case_types)]
934 trait UselessPinnedDropImpl_you_need_t 892 trait UselessPinnedDropImpl_you_need_to_specify_PinnedDrop {}
935 impl<T: $crate::init::PinnedDrop> 893 impl<T: $crate::init::PinnedDrop>
936 UselessPinnedDropImpl_you_need_to_ 894 UselessPinnedDropImpl_you_need_to_specify_PinnedDrop for T {}
937 impl<$($impl_generics)*> 895 impl<$($impl_generics)*>
938 UselessPinnedDropImpl_you_need_to_ 896 UselessPinnedDropImpl_you_need_to_specify_PinnedDrop for $name<$($ty_generics)*>
939 where $($whr)* {} 897 where $($whr)* {}
940 }; 898 };
941 // When `PinnedDrop` was specified we just 899 // When `PinnedDrop` was specified we just implement `Drop` and delegate.
942 (drop_prevention: 900 (drop_prevention:
943 @name($name:ident), 901 @name($name:ident),
944 @impl_generics($($impl_generics:tt)*), 902 @impl_generics($($impl_generics:tt)*),
945 @ty_generics($($ty_generics:tt)*), 903 @ty_generics($($ty_generics:tt)*),
946 @where($($whr:tt)*), 904 @where($($whr:tt)*),
947 @pinned_drop(PinnedDrop), 905 @pinned_drop(PinnedDrop),
948 ) => { 906 ) => {
949 impl<$($impl_generics)*> ::core::ops:: 907 impl<$($impl_generics)*> ::core::ops::Drop for $name<$($ty_generics)*>
950 where $($whr)* 908 where $($whr)*
951 { 909 {
952 fn drop(&mut self) { 910 fn drop(&mut self) {
953 // SAFETY: Since this is a des 911 // SAFETY: Since this is a destructor, `self` will not move after this function
954 // terminates, since it is ina 912 // terminates, since it is inaccessible.
955 let pinned = unsafe { ::core:: 913 let pinned = unsafe { ::core::pin::Pin::new_unchecked(self) };
956 // SAFETY: Since this is a dro 914 // SAFETY: Since this is a drop function, we can create this token to call the
957 // pinned destructor of this t 915 // pinned destructor of this type.
958 let token = unsafe { $crate::i 916 let token = unsafe { $crate::init::__internal::OnlyCallFromDrop::new() };
959 $crate::init::PinnedDrop::drop 917 $crate::init::PinnedDrop::drop(pinned, token);
960 } 918 }
961 } 919 }
962 }; 920 };
963 // If some other parameter was specified, 921 // If some other parameter was specified, we emit a readable error.
964 (drop_prevention: 922 (drop_prevention:
965 @name($name:ident), 923 @name($name:ident),
966 @impl_generics($($impl_generics:tt)*), 924 @impl_generics($($impl_generics:tt)*),
967 @ty_generics($($ty_generics:tt)*), 925 @ty_generics($($ty_generics:tt)*),
968 @where($($whr:tt)*), 926 @where($($whr:tt)*),
969 @pinned_drop($($rest:tt)*), 927 @pinned_drop($($rest:tt)*),
970 ) => { 928 ) => {
971 compile_error!( 929 compile_error!(
972 "Wrong parameters to `#[pin_data]` 930 "Wrong parameters to `#[pin_data]`, expected nothing or `PinnedDrop`, got '{}'.",
973 stringify!($($rest)*), 931 stringify!($($rest)*),
974 ); 932 );
975 }; 933 };
976 (make_pin_data: 934 (make_pin_data:
977 @pin_data($pin_data:ident), 935 @pin_data($pin_data:ident),
978 @impl_generics($($impl_generics:tt)*), 936 @impl_generics($($impl_generics:tt)*),
979 @ty_generics($($ty_generics:tt)*), 937 @ty_generics($($ty_generics:tt)*),
980 @where($($whr:tt)*), 938 @where($($whr:tt)*),
981 @pinned($($(#[$($p_attr:tt)*])* $pvis: 939 @pinned($($(#[$($p_attr:tt)*])* $pvis:vis $p_field:ident : $p_type:ty),* $(,)?),
982 @not_pinned($($(#[$($attr:tt)*])* $fvi 940 @not_pinned($($(#[$($attr:tt)*])* $fvis:vis $field:ident : $type:ty),* $(,)?),
983 ) => { 941 ) => {
984 // For every field, we create a projec 942 // For every field, we create a projection function according to its projection type. If a
985 // field is structurally pinned, then 943 // field is structurally pinned, then it must be initialized via `PinInit`, if it is not
986 // structurally pinned, then it can be 944 // structurally pinned, then it can be initialized via `Init`.
987 // 945 //
988 // The functions are `unsafe` to preve 946 // The functions are `unsafe` to prevent accidentally calling them.
989 #[allow(dead_code)] 947 #[allow(dead_code)]
990 impl<$($impl_generics)*> $pin_data<$($ 948 impl<$($impl_generics)*> $pin_data<$($ty_generics)*>
991 where $($whr)* 949 where $($whr)*
992 { 950 {
993 $( 951 $(
994 $(#[$($p_attr)*])* <<
995 $pvis unsafe fn $p_field<E>( 952 $pvis unsafe fn $p_field<E>(
996 self, 953 self,
997 slot: *mut $p_type, 954 slot: *mut $p_type,
998 init: impl $crate::init::P 955 init: impl $crate::init::PinInit<$p_type, E>,
999 ) -> ::core::result::Result<() 956 ) -> ::core::result::Result<(), E> {
1000 unsafe { $crate::init::Pi 957 unsafe { $crate::init::PinInit::__pinned_init(init, slot) }
1001 } 958 }
1002 )* 959 )*
1003 $( 960 $(
1004 $(#[$($attr)*])* <<
1005 $fvis unsafe fn $field<E>( 961 $fvis unsafe fn $field<E>(
1006 self, 962 self,
1007 slot: *mut $type, 963 slot: *mut $type,
1008 init: impl $crate::init:: 964 init: impl $crate::init::Init<$type, E>,
1009 ) -> ::core::result::Result<( 965 ) -> ::core::result::Result<(), E> {
1010 unsafe { $crate::init::In 966 unsafe { $crate::init::Init::__init(init, slot) }
1011 } 967 }
1012 )* 968 )*
1013 } 969 }
1014 }; <<
1015 } <<
1016 <<
1017 /// The internal init macro. Do not call manu <<
1018 /// <<
1019 /// This is called by the `{try_}{pin_}init!` <<
1020 /// <<
1021 /// This macro has multiple internal call con <<
1022 /// - nothing: this is the base case and call <<
1023 /// - `with_update_parsed`: when the `..Zeroa <<
1024 /// - `init_slot`: recursively creates the co <<
1025 /// - `make_initializer`: recursively create <<
1026 /// field has been initialized exactly once <<
1027 #[doc(hidden)] <<
1028 #[macro_export] <<
1029 macro_rules! __init_internal { <<
1030 ( <<
1031 @this($($this:ident)?), <<
1032 @typ($t:path), <<
1033 @fields($($fields:tt)*), <<
1034 @error($err:ty), <<
1035 // Either `PinData` or `InitData`, `$ <<
1036 // case. <<
1037 @data($data:ident, $($use_data:ident) <<
1038 // `HasPinData` or `HasInitData`. <<
1039 @has_data($has_data:ident, $get_data: <<
1040 // `pin_init_from_closure` or `init_f <<
1041 @construct_closure($construct_closure <<
1042 @munch_fields(), <<
1043 ) => { <<
1044 $crate::__init_internal!(with_update_ <<
1045 @this($($this)?), <<
1046 @typ($t), <<
1047 @fields($($fields)*), <<
1048 @error($err), <<
1049 @data($data, $($use_data)?), <<
1050 @has_data($has_data, $get_data), <<
1051 @construct_closure($construct_clo <<
1052 @zeroed(), // Nothing means defau <<
1053 ) <<
1054 }; <<
1055 ( <<
1056 @this($($this:ident)?), <<
1057 @typ($t:path), <<
1058 @fields($($fields:tt)*), <<
1059 @error($err:ty), <<
1060 // Either `PinData` or `InitData`, `$ <<
1061 // case. <<
1062 @data($data:ident, $($use_data:ident) <<
1063 // `HasPinData` or `HasInitData`. <<
1064 @has_data($has_data:ident, $get_data: <<
1065 // `pin_init_from_closure` or `init_f <<
1066 @construct_closure($construct_closure <<
1067 @munch_fields(..Zeroable::zeroed()), <<
1068 ) => { <<
1069 $crate::__init_internal!(with_update_ <<
1070 @this($($this)?), <<
1071 @typ($t), <<
1072 @fields($($fields)*), <<
1073 @error($err), <<
1074 @data($data, $($use_data)?), <<
1075 @has_data($has_data, $get_data), <<
1076 @construct_closure($construct_clo <<
1077 @zeroed(()), // `()` means zero a <<
1078 ) <<
1079 }; <<
1080 ( <<
1081 @this($($this:ident)?), <<
1082 @typ($t:path), <<
1083 @fields($($fields:tt)*), <<
1084 @error($err:ty), <<
1085 // Either `PinData` or `InitData`, `$ <<
1086 // case. <<
1087 @data($data:ident, $($use_data:ident) <<
1088 // `HasPinData` or `HasInitData`. <<
1089 @has_data($has_data:ident, $get_data: <<
1090 // `pin_init_from_closure` or `init_f <<
1091 @construct_closure($construct_closure <<
1092 @munch_fields($ignore:tt $($rest:tt)* <<
1093 ) => { <<
1094 $crate::__init_internal!( <<
1095 @this($($this)?), <<
1096 @typ($t), <<
1097 @fields($($fields)*), <<
1098 @error($err), <<
1099 @data($data, $($use_data)?), <<
1100 @has_data($has_data, $get_data), <<
1101 @construct_closure($construct_clo <<
1102 @munch_fields($($rest)*), <<
1103 ) <<
1104 }; <<
1105 (with_update_parsed: <<
1106 @this($($this:ident)?), <<
1107 @typ($t:path), <<
1108 @fields($($fields:tt)*), <<
1109 @error($err:ty), <<
1110 // Either `PinData` or `InitData`, `$ <<
1111 // case. <<
1112 @data($data:ident, $($use_data:ident) <<
1113 // `HasPinData` or `HasInitData`. <<
1114 @has_data($has_data:ident, $get_data: <<
1115 // `pin_init_from_closure` or `init_f <<
1116 @construct_closure($construct_closure <<
1117 @zeroed($($init_zeroed:expr)?), <<
1118 ) => {{ <<
1119 // We do not want to allow arbitrary <<
1120 // type and shadow it later when we i <<
1121 // no possibility of returning withou <<
1122 struct __InitOk; <<
1123 // Get the data about fields from the <<
1124 let data = unsafe { <<
1125 use $crate::init::__internal::$ha <<
1126 // Here we abuse `paste!` to reto <<
1127 // information that is associated <<
1128 // cannot be used in this positio <<
1129 // code. <<
1130 ::kernel::macros::paste!($t::$get <<
1131 }; <<
1132 // Ensure that `data` really is of ty <<
1133 let init = $crate::init::__internal:: <<
1134 data, <<
1135 move |slot| { <<
1136 { <<
1137 // Shadow the structure s <<
1138 struct __InitOk; <<
1139 // If `$init_zeroed` is p <<
1140 // error when fields are <<
1141 // check that the type ac <<
1142 $({ <<
1143 fn assert_zeroable<T: <<
1144 // Ensure that the st <<
1145 assert_zeroable(slot) <<
1146 // SAFETY: The type i <<
1147 unsafe { ::core::ptr: <<
1148 $init_zeroed // This <<
1149 })? <<
1150 // Create the `this` so i <<
1151 // expressions creating t <<
1152 $(let $this = unsafe { :: <<
1153 // Initialize every field <<
1154 $crate::__init_internal!( <<
1155 @data(data), <<
1156 @slot(slot), <<
1157 @guards(), <<
1158 @munch_fields($($fiel <<
1159 ); <<
1160 // We use unreachable cod <<
1161 // once, this struct init <<
1162 // very natural error mes <<
1163 #[allow(unreachable_code, <<
1164 let _ = || { <<
1165 $crate::__init_intern <<
1166 @slot(slot), <<
1167 @type_name($t), <<
1168 @munch_fields($($ <<
1169 @acc(), <<
1170 ); <<
1171 }; <<
1172 } <<
1173 Ok(__InitOk) <<
1174 } <<
1175 ); <<
1176 let init = move |slot| -> ::core::res <<
1177 init(slot).map(|__InitOk| ()) <<
1178 }; <<
1179 let init = unsafe { $crate::init::$co <<
1180 init <<
1181 }}; <<
1182 (init_slot($($use_data:ident)?): <<
1183 @data($data:ident), <<
1184 @slot($slot:ident), <<
1185 @guards($($guards:ident,)*), <<
1186 @munch_fields($(..Zeroable::zeroed()) <<
1187 ) => { <<
1188 // Endpoint of munching, no fields ar <<
1189 // have been initialized. Therefore w <<
1190 $(::core::mem::forget($guards);)* <<
1191 }; <<
1192 (init_slot($use_data:ident): // `use_data <<
1193 @data($data:ident), <<
1194 @slot($slot:ident), <<
1195 @guards($($guards:ident,)*), <<
1196 // In-place initialization syntax. <<
1197 @munch_fields($field:ident <- $val:ex <<
1198 ) => { <<
1199 let init = $val; <<
1200 // Call the initializer. <<
1201 // <<
1202 // SAFETY: `slot` is valid, because w <<
1203 // return when an error/panic occurs. <<
1204 // We also use the `data` to require <<
1205 unsafe { $data.$field(::core::ptr::ad <<
1206 // Create the drop guard: <<
1207 // <<
1208 // We rely on macro hygiene to make i <<
1209 // We use `paste!` to create new hygi <<
1210 ::kernel::macros::paste! { <<
1211 // SAFETY: We forget the guard la <<
1212 let [< __ $field _guard >] = unsa <<
1213 $crate::init::__internal::Dro <<
1214 }; <<
1215 <<
1216 $crate::__init_internal!(init_slo <<
1217 @data($data), <<
1218 @slot($slot), <<
1219 @guards([< __ $field _guard > <<
1220 @munch_fields($($rest)*), <<
1221 ); <<
1222 } <<
1223 }; <<
1224 (init_slot(): // No `use_data`, so we use <<
1225 @data($data:ident), <<
1226 @slot($slot:ident), <<
1227 @guards($($guards:ident,)*), <<
1228 // In-place initialization syntax. <<
1229 @munch_fields($field:ident <- $val:ex <<
1230 ) => { <<
1231 let init = $val; <<
1232 // Call the initializer. <<
1233 // <<
1234 // SAFETY: `slot` is valid, because w <<
1235 // return when an error/panic occurs. <<
1236 unsafe { $crate::init::Init::__init(i <<
1237 // Create the drop guard: <<
1238 // <<
1239 // We rely on macro hygiene to make i <<
1240 // We use `paste!` to create new hygi <<
1241 ::kernel::macros::paste! { <<
1242 // SAFETY: We forget the guard la <<
1243 let [< __ $field _guard >] = unsa <<
1244 $crate::init::__internal::Dro <<
1245 }; <<
1246 <<
1247 $crate::__init_internal!(init_slo <<
1248 @data($data), <<
1249 @slot($slot), <<
1250 @guards([< __ $field _guard > <<
1251 @munch_fields($($rest)*), <<
1252 ); <<
1253 } <<
1254 }; <<
1255 (init_slot($($use_data:ident)?): <<
1256 @data($data:ident), <<
1257 @slot($slot:ident), <<
1258 @guards($($guards:ident,)*), <<
1259 // Init by-value. <<
1260 @munch_fields($field:ident $(: $val:e <<
1261 ) => { <<
1262 { <<
1263 $(let $field = $val;)? <<
1264 // Initialize the field. <<
1265 // <<
1266 // SAFETY: The memory at `slot` i <<
1267 unsafe { ::core::ptr::write(::cor <<
1268 } <<
1269 // Create the drop guard: <<
1270 // <<
1271 // We rely on macro hygiene to make i <<
1272 // We use `paste!` to create new hygi <<
1273 ::kernel::macros::paste! { <<
1274 // SAFETY: We forget the guard la <<
1275 let [< __ $field _guard >] = unsa <<
1276 $crate::init::__internal::Dro <<
1277 }; <<
1278 <<
1279 $crate::__init_internal!(init_slo <<
1280 @data($data), <<
1281 @slot($slot), <<
1282 @guards([< __ $field _guard > <<
1283 @munch_fields($($rest)*), <<
1284 ); <<
1285 } <<
1286 }; <<
1287 (make_initializer: <<
1288 @slot($slot:ident), <<
1289 @type_name($t:path), <<
1290 @munch_fields(..Zeroable::zeroed() $( <<
1291 @acc($($acc:tt)*), <<
1292 ) => { <<
1293 // Endpoint, nothing more to munch, c <<
1294 // `..Zeroable::zeroed()`, the slot w <<
1295 // not been overwritten are thus zero <<
1296 // actually accessible by using the s <<
1297 // We are inside of a closure that is <<
1298 // get the correct type inference her <<
1299 #[allow(unused_assignments)] <<
1300 unsafe { <<
1301 let mut zeroed = ::core::mem::zer <<
1302 // We have to use type inference <<
1303 // not get executed, so it has no <<
1304 ::core::ptr::write($slot, zeroed) <<
1305 zeroed = ::core::mem::zeroed(); <<
1306 // Here we abuse `paste!` to reto <<
1307 // information that is associated <<
1308 // cannot be used in this positio <<
1309 // code. <<
1310 ::kernel::macros::paste!( <<
1311 ::core::ptr::write($slot, $t <<
1312 $($acc)* <<
1313 ..zeroed <<
1314 }); <<
1315 ); <<
1316 } <<
1317 }; <<
1318 (make_initializer: <<
1319 @slot($slot:ident), <<
1320 @type_name($t:path), <<
1321 @munch_fields($(,)?), <<
1322 @acc($($acc:tt)*), <<
1323 ) => { <<
1324 // Endpoint, nothing more to munch, c <<
1325 // Since we are in the closure that i <<
1326 // We abuse `slot` to get the correct <<
1327 unsafe { <<
1328 // Here we abuse `paste!` to reto <<
1329 // information that is associated <<
1330 // cannot be used in this positio <<
1331 // code. <<
1332 ::kernel::macros::paste!( <<
1333 ::core::ptr::write($slot, $t <<
1334 $($acc)* <<
1335 }); <<
1336 ); <<
1337 } <<
1338 }; <<
1339 (make_initializer: <<
1340 @slot($slot:ident), <<
1341 @type_name($t:path), <<
1342 @munch_fields($field:ident <- $val:ex <<
1343 @acc($($acc:tt)*), <<
1344 ) => { <<
1345 $crate::__init_internal!(make_initial <<
1346 @slot($slot), <<
1347 @type_name($t), <<
1348 @munch_fields($($rest)*), <<
1349 @acc($($acc)* $field: ::core::pan <<
1350 ); <<
1351 }; <<
1352 (make_initializer: <<
1353 @slot($slot:ident), <<
1354 @type_name($t:path), <<
1355 @munch_fields($field:ident $(: $val:e <<
1356 @acc($($acc:tt)*), <<
1357 ) => { <<
1358 $crate::__init_internal!(make_initial <<
1359 @slot($slot), <<
1360 @type_name($t), <<
1361 @munch_fields($($rest)*), <<
1362 @acc($($acc)* $field: ::core::pan <<
1363 ); <<
1364 }; <<
1365 } <<
1366 <<
1367 #[doc(hidden)] <<
1368 #[macro_export] <<
1369 macro_rules! __derive_zeroable { <<
1370 (parse_input: <<
1371 @sig( <<
1372 $(#[$($struct_attr:tt)*])* <<
1373 $vis:vis struct $name:ident <<
1374 $(where $($whr:tt)*)? <<
1375 ), <<
1376 @impl_generics($($impl_generics:tt)*) <<
1377 @ty_generics($($ty_generics:tt)*), <<
1378 @body({ <<
1379 $( <<
1380 $(#[$($field_attr:tt)*])* <<
1381 $field:ident : $field_ty:ty <<
1382 ),* $(,)? <<
1383 }), <<
1384 ) => { <<
1385 // SAFETY: Every field type implement <<
1386 #[automatically_derived] <<
1387 unsafe impl<$($impl_generics)*> $crat <<
1388 where <<
1389 $($($whr)*)? <<
1390 {} <<
1391 const _: () = { <<
1392 fn assert_zeroable<T: ?::core::ma <<
1393 fn ensure_zeroable<$($impl_generi <<
1394 where $($($whr)*)? <<
1395 { <<
1396 $(assert_zeroable::<$field_ty <<
1397 } <<
1398 }; <<
1399 }; 970 };
1400 } 971 }
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.