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,ignore
22 //! # use kernel::init::*; 20 //! # use kernel::init::*;
23 //! # use core::pin::Pin; 21 //! # use core::pin::Pin;
24 //! #[pin_data] 22 //! #[pin_data]
25 //! #[repr(C)] 23 //! #[repr(C)]
26 //! struct Bar<T> { 24 //! struct Bar<T> {
27 //! #[pin] 25 //! #[pin]
28 //! t: T, 26 //! t: T,
29 //! pub x: usize, 27 //! pub x: usize,
30 //! } 28 //! }
31 //! 29 //!
32 //! impl<T> Bar<T> { 30 //! impl<T> Bar<T> {
33 //! fn new(t: T) -> impl PinInit<Self> { 31 //! fn new(t: T) -> impl PinInit<Self> {
34 //! pin_init!(Self { t, x: 0 }) 32 //! pin_init!(Self { t, x: 0 })
35 //! } 33 //! }
36 //! } 34 //! }
37 //! 35 //!
38 //! #[pin_data(PinnedDrop)] 36 //! #[pin_data(PinnedDrop)]
39 //! struct Foo { 37 //! struct Foo {
40 //! a: usize, 38 //! a: usize,
41 //! #[pin] 39 //! #[pin]
42 //! b: Bar<u32>, 40 //! b: Bar<u32>,
43 //! } 41 //! }
44 //! 42 //!
45 //! #[pinned_drop] 43 //! #[pinned_drop]
46 //! impl PinnedDrop for Foo { 44 //! impl PinnedDrop for Foo {
47 //! fn drop(self: Pin<&mut Self>) { 45 //! fn drop(self: Pin<&mut Self>) {
48 //! pr_info!("{self:p} is getting drop !! 46 //! println!("{self:p} is getting dropped.");
49 //! } 47 //! }
50 //! } 48 //! }
51 //! 49 //!
52 //! let a = 42; 50 //! let a = 42;
53 //! let initializer = pin_init!(Foo { 51 //! let initializer = pin_init!(Foo {
54 //! a, 52 //! a,
55 //! b <- Bar::new(36), 53 //! b <- Bar::new(36),
56 //! }); 54 //! });
57 //! ``` 55 //! ```
58 //! 56 //!
59 //! This example includes the most common and 57 //! This example includes the most common and important features of the pin-init API.
60 //! 58 //!
61 //! Below you can find individual section abou 59 //! Below you can find individual section about the different macro invocations. Here are some
62 //! general things we need to take into accoun 60 //! general things we need to take into account when designing macros:
63 //! - use global paths, similarly to file path 61 //! - use global paths, similarly to file paths, these start with the separator: `::core::panic!()`
64 //! this ensures that the correct item is us 62 //! 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 63 //! and then their own `panic!` inside to execute arbitrary code inside of our macro.
66 //! - macro `unsafe` hygiene: we need to ensur 64 //! - macro `unsafe` hygiene: we need to ensure that we do not expand arbitrary, user-supplied
67 //! expressions inside of an `unsafe` block 65 //! expressions inside of an `unsafe` block in the macro, because this would allow users to do
68 //! `unsafe` operations without an associate 66 //! `unsafe` operations without an associated `unsafe` block.
69 //! 67 //!
70 //! ## `#[pin_data]` on `Bar` 68 //! ## `#[pin_data]` on `Bar`
71 //! 69 //!
72 //! This macro is used to specify which fields 70 //! 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 71 //! is placed on the struct definition and allows `#[pin]` to be placed on the fields.
74 //! 72 //!
75 //! Here is the definition of `Bar` from our e 73 //! Here is the definition of `Bar` from our example:
76 //! 74 //!
77 //! ```rust,ignore 75 //! ```rust,ignore
78 //! # use kernel::init::*; 76 //! # use kernel::init::*;
79 //! #[pin_data] 77 //! #[pin_data]
80 //! #[repr(C)] 78 //! #[repr(C)]
81 //! struct Bar<T> { 79 //! struct Bar<T> {
82 //! #[pin] 80 //! #[pin]
83 //! t: T, 81 //! t: T,
84 //! pub x: usize, 82 //! pub x: usize,
85 //! } 83 //! }
86 //! ``` 84 //! ```
87 //! 85 //!
88 //! This expands to the following code: 86 //! This expands to the following code:
89 //! 87 //!
90 //! ```rust,ignore 88 //! ```rust,ignore
91 //! // Firstly the normal definition of the st 89 //! // Firstly the normal definition of the struct, attributes are preserved:
92 //! #[repr(C)] 90 //! #[repr(C)]
93 //! struct Bar<T> { 91 //! struct Bar<T> {
94 //! t: T, 92 //! t: T,
95 //! pub x: usize, 93 //! pub x: usize,
96 //! } 94 //! }
97 //! // Then an anonymous constant is defined, 95 //! // Then an anonymous constant is defined, this is because we do not want any code to access the
98 //! // types that we define inside: 96 //! // types that we define inside:
99 //! const _: () = { 97 //! const _: () = {
100 //! // We define the pin-data carrying str 98 //! // 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 99 //! // since we need to implement access functions for each field and thus need to know its
102 //! // type. 100 //! // type.
103 //! struct __ThePinData<T> { 101 //! struct __ThePinData<T> {
104 //! __phantom: ::core::marker::Phantom 102 //! __phantom: ::core::marker::PhantomData<fn(Bar<T>) -> Bar<T>>,
105 //! } 103 //! }
106 //! // We implement `Copy` for the pin-dat 104 //! // We implement `Copy` for the pin-data struct, since all functions it defines will take
107 //! // `self` by value. 105 //! // `self` by value.
108 //! impl<T> ::core::clone::Clone for __The 106 //! impl<T> ::core::clone::Clone for __ThePinData<T> {
109 //! fn clone(&self) -> Self { 107 //! fn clone(&self) -> Self {
110 //! *self 108 //! *self
111 //! } 109 //! }
112 //! } 110 //! }
113 //! impl<T> ::core::marker::Copy for __The 111 //! impl<T> ::core::marker::Copy for __ThePinData<T> {}
114 //! // For every field of `Bar`, the pin-d 112 //! // For every field of `Bar`, the pin-data struct will define a function with the same name
115 //! // and accessor (`pub` or `pub(crate)` 113 //! // and accessor (`pub` or `pub(crate)` etc.). This function will take a pointer to the
116 //! // field (`slot`) and a `PinInit` or ` 114 //! // field (`slot`) and a `PinInit` or `Init` depending on the projection kind of the field
117 //! // (if pinning is structural for the f 115 //! // (if pinning is structural for the field, then `PinInit` otherwise `Init`).
118 //! #[allow(dead_code)] 116 //! #[allow(dead_code)]
119 //! impl<T> __ThePinData<T> { 117 //! impl<T> __ThePinData<T> {
120 //! unsafe fn t<E>( 118 //! unsafe fn t<E>(
121 //! self, 119 //! self,
122 //! slot: *mut T, 120 //! slot: *mut T,
123 //! // Since `t` is `#[pin]`, this 121 //! // Since `t` is `#[pin]`, this is `PinInit`.
124 //! init: impl ::kernel::init::Pin 122 //! init: impl ::kernel::init::PinInit<T, E>,
125 //! ) -> ::core::result::Result<(), E> 123 //! ) -> ::core::result::Result<(), E> {
126 //! unsafe { ::kernel::init::PinIn 124 //! unsafe { ::kernel::init::PinInit::__pinned_init(init, slot) }
127 //! } 125 //! }
128 //! pub unsafe fn x<E>( 126 //! pub unsafe fn x<E>(
129 //! self, 127 //! self,
130 //! slot: *mut usize, 128 //! slot: *mut usize,
131 //! // Since `x` is not `#[pin]`, 129 //! // Since `x` is not `#[pin]`, this is `Init`.
132 //! init: impl ::kernel::init::Ini 130 //! init: impl ::kernel::init::Init<usize, E>,
133 //! ) -> ::core::result::Result<(), E> 131 //! ) -> ::core::result::Result<(), E> {
134 //! unsafe { ::kernel::init::Init: 132 //! unsafe { ::kernel::init::Init::__init(init, slot) }
135 //! } 133 //! }
136 //! } 134 //! }
137 //! // Implement the internal `HasPinData` 135 //! // Implement the internal `HasPinData` trait that associates `Bar` with the pin-data struct
138 //! // that we constructed above. 136 //! // that we constructed above.
139 //! unsafe impl<T> ::kernel::init::__inter 137 //! unsafe impl<T> ::kernel::init::__internal::HasPinData for Bar<T> {
140 //! type PinData = __ThePinData<T>; 138 //! type PinData = __ThePinData<T>;
141 //! unsafe fn __pin_data() -> Self::Pi 139 //! unsafe fn __pin_data() -> Self::PinData {
142 //! __ThePinData { 140 //! __ThePinData {
143 //! __phantom: ::core::marker: 141 //! __phantom: ::core::marker::PhantomData,
144 //! } 142 //! }
145 //! } 143 //! }
146 //! } 144 //! }
147 //! // Implement the internal `PinData` tr 145 //! // Implement the internal `PinData` trait that marks the pin-data struct as a pin-data
148 //! // struct. This is important to ensure !! 146 //! // struct. This is important to ensure that no user can implement a rouge `__pin_data`
149 //! // function without using `unsafe`. 147 //! // function without using `unsafe`.
150 //! unsafe impl<T> ::kernel::init::__inter 148 //! unsafe impl<T> ::kernel::init::__internal::PinData for __ThePinData<T> {
151 //! type Datee = Bar<T>; 149 //! type Datee = Bar<T>;
152 //! } 150 //! }
153 //! // Now we only want to implement `Unpi 151 //! // Now we only want to implement `Unpin` for `Bar` when every structurally pinned field is
154 //! // `Unpin`. In other words, whether `B 152 //! // `Unpin`. In other words, whether `Bar` is `Unpin` only depends on structurally pinned
155 //! // fields (those marked with `#[pin]`) 153 //! // fields (those marked with `#[pin]`). These fields will be listed in this struct, in our
156 //! // case no such fields exist, hence th 154 //! // case no such fields exist, hence this is almost empty. The two phantomdata fields exist
157 //! // for two reasons: 155 //! // for two reasons:
158 //! // - `__phantom`: every generic must b 156 //! // - `__phantom`: every generic must be used, since we cannot really know which generics
159 //! // are used, we declare all and then !! 157 //! // are used, we declere all and then use everything here once.
160 //! // - `__phantom_pin`: uses the `'__pin 158 //! // - `__phantom_pin`: uses the `'__pin` lifetime and ensures that this struct is invariant
161 //! // over it. The lifetime is needed t 159 //! // over it. The lifetime is needed to work around the limitation that trait bounds must
162 //! // not be trivial, e.g. the user has 160 //! // not be trivial, e.g. the user has a `#[pin] PhantomPinned` field -- this is
163 //! // unconditionally `!Unpin` and resu 161 //! // unconditionally `!Unpin` and results in an error. The lifetime tricks the compiler
164 //! // into accepting these bounds regar 162 //! // into accepting these bounds regardless.
165 //! #[allow(dead_code)] 163 //! #[allow(dead_code)]
166 //! struct __Unpin<'__pin, T> { 164 //! struct __Unpin<'__pin, T> {
167 //! __phantom_pin: ::core::marker::Pha 165 //! __phantom_pin: ::core::marker::PhantomData<fn(&'__pin ()) -> &'__pin ()>,
168 //! __phantom: ::core::marker::Phantom 166 //! __phantom: ::core::marker::PhantomData<fn(Bar<T>) -> Bar<T>>,
169 //! // Our only `#[pin]` field is `t`. 167 //! // Our only `#[pin]` field is `t`.
170 //! t: T, 168 //! t: T,
171 //! } 169 //! }
172 //! #[doc(hidden)] 170 //! #[doc(hidden)]
173 //! impl<'__pin, T> ::core::marker::Unpin !! 171 //! impl<'__pin, T>
174 //! where !! 172 //! ::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 173 //! // Now we need to ensure that `Bar` does not implement `Drop`, since that would give users
178 //! // access to `&mut self` inside of `dr 174 //! // 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 175 //! // UB with only safe code, so we disallow this by giving a trait implementation error using
180 //! // a direct impl and a blanket impleme 176 //! // a direct impl and a blanket implementation.
181 //! trait MustNotImplDrop {} 177 //! trait MustNotImplDrop {}
182 //! // Normally `Drop` bounds do not have 178 //! // Normally `Drop` bounds do not have the correct semantics, but for this purpose they do
183 //! // (normally people want to know if a 179 //! // (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 180 //! // to know if it has any kind of custom drop glue, which is exactly what this bound does).
185 //! #[allow(drop_bounds)] 181 //! #[allow(drop_bounds)]
186 //! impl<T: ::core::ops::Drop> MustNotImpl 182 //! impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
187 //! impl<T> MustNotImplDrop for Bar<T> {} 183 //! impl<T> MustNotImplDrop for Bar<T> {}
188 //! // Here comes a convenience check, if 184 //! // Here comes a convenience check, if one implemented `PinnedDrop`, but forgot to add it to
189 //! // `#[pin_data]`, then this will error 185 //! // `#[pin_data]`, then this will error with the same mechanic as above, this is not needed
190 //! // for safety, but a good sanity check 186 //! // for safety, but a good sanity check, since no normal code calls `PinnedDrop::drop`.
191 //! #[allow(non_camel_case_types)] 187 //! #[allow(non_camel_case_types)]
192 //! trait UselessPinnedDropImpl_you_need_t 188 //! trait UselessPinnedDropImpl_you_need_to_specify_PinnedDrop {}
193 //! impl< !! 189 //! impl<T: ::kernel::init::PinnedDrop>
194 //! T: ::kernel::init::PinnedDrop, !! 190 //! UselessPinnedDropImpl_you_need_to_specify_PinnedDrop for T {}
195 //! > UselessPinnedDropImpl_you_need_to_sp <<
196 //! impl<T> UselessPinnedDropImpl_you_need 191 //! impl<T> UselessPinnedDropImpl_you_need_to_specify_PinnedDrop for Bar<T> {}
197 //! }; 192 //! };
198 //! ``` 193 //! ```
199 //! 194 //!
200 //! ## `pin_init!` in `impl Bar` 195 //! ## `pin_init!` in `impl Bar`
201 //! 196 //!
202 //! This macro creates an pin-initializer for 197 //! This macro creates an pin-initializer for the given struct. It requires that the struct is
203 //! annotated by `#[pin_data]`. 198 //! annotated by `#[pin_data]`.
204 //! 199 //!
205 //! Here is the impl on `Bar` defining the new 200 //! Here is the impl on `Bar` defining the new function:
206 //! 201 //!
207 //! ```rust,ignore 202 //! ```rust,ignore
208 //! impl<T> Bar<T> { 203 //! impl<T> Bar<T> {
209 //! fn new(t: T) -> impl PinInit<Self> { 204 //! fn new(t: T) -> impl PinInit<Self> {
210 //! pin_init!(Self { t, x: 0 }) 205 //! pin_init!(Self { t, x: 0 })
211 //! } 206 //! }
212 //! } 207 //! }
213 //! ``` 208 //! ```
214 //! 209 //!
215 //! This expands to the following code: 210 //! This expands to the following code:
216 //! 211 //!
217 //! ```rust,ignore 212 //! ```rust,ignore
218 //! impl<T> Bar<T> { 213 //! impl<T> Bar<T> {
219 //! fn new(t: T) -> impl PinInit<Self> { 214 //! fn new(t: T) -> impl PinInit<Self> {
220 //! { 215 //! {
221 //! // We do not want to allow arb 216 //! // We do not want to allow arbitrary returns, so we declare this type as the `Ok`
222 //! // return type and shadow it l 217 //! // return type and shadow it later when we insert the arbitrary user code. That way
223 //! // there will be no possibilit 218 //! // there will be no possibility of returning without `unsafe`.
224 //! struct __InitOk; 219 //! struct __InitOk;
225 //! // Get the data about fields f !! 220 //! // Get the pin-data type from the initialized type.
226 //! // - the function is unsafe, h 221 //! // - the function is unsafe, hence the unsafe block
227 //! // - we `use` the `HasPinData` 222 //! // - we `use` the `HasPinData` trait in the block, it is only available in that
228 //! // scope. 223 //! // scope.
229 //! let data = unsafe { 224 //! let data = unsafe {
230 //! use ::kernel::init::__inte 225 //! use ::kernel::init::__internal::HasPinData;
231 //! Self::__pin_data() 226 //! Self::__pin_data()
232 //! }; 227 //! };
233 //! // Ensure that `data` really i !! 228 //! // Use `data` to help with type inference, the closure supplied will have the type
>> 229 //! // `FnOnce(*mut Self) -> Result<__InitOk, Infallible>`.
234 //! let init = ::kernel::init::__i 230 //! let init = ::kernel::init::__internal::PinData::make_closure::<
235 //! _, 231 //! _,
236 //! __InitOk, 232 //! __InitOk,
237 //! ::core::convert::Infallibl 233 //! ::core::convert::Infallible,
238 //! >(data, move |slot| { 234 //! >(data, move |slot| {
239 //! { 235 //! {
240 //! // Shadow the structur 236 //! // Shadow the structure so it cannot be used to return early. If a user
241 //! // tries to write `ret !! 237 //! // tries to write `return Ok(__InitOk)`, then they get a type error, since
242 //! // since that will ref !! 238 //! // that will refer to this struct instead of the one defined above.
243 //! // above. <<
244 //! struct __InitOk; 239 //! struct __InitOk;
245 //! // This is the expansi 240 //! // This is the expansion of `t,`, which is syntactic sugar for `t: t,`.
246 //! { !! 241 //! unsafe { ::core::ptr::write(::core::addr_of_mut!((*slot).t), t) };
247 //! unsafe { ::core::p !! 242 //! // Since initialization could fail later (not in this case, since the error
248 //! } !! 243 //! // type is `Infallible`) we will need to drop this field if there is an
249 //! // Since initializatio !! 244 //! // error later. This `DropGuard` will drop the field when it gets dropped
250 //! // error type is `Infa !! 245 //! // and has not yet been forgotten. We make a reference to it, so users
251 //! // is an error later. !! 246 //! // cannot `mem::forget` it from the initializer, since the name is the same
252 //! // dropped and has not !! 247 //! // as the field (including hygiene).
253 //! let __t_guard = unsafe !! 248 //! let t = &unsafe {
254 //! ::pinned_init::__i !! 249 //! ::kernel::init::__internal::DropGuard::new(
>> 250 //! ::core::addr_of_mut!((*slot).t),
>> 251 //! )
255 //! }; 252 //! };
256 //! // Expansion of `x: 0, 253 //! // Expansion of `x: 0,`:
257 //! // Since this can be a !! 254 //! // Since this can be an arbitrary expression we cannot place it inside of
258 //! // of the `unsafe` blo !! 255 //! // the `unsafe` block, so we bind it here.
259 //! { !! 256 //! let x = 0;
260 //! let x = 0; !! 257 //! unsafe { ::core::ptr::write(::core::addr_of_mut!((*slot).x), x) };
261 //! unsafe { ::core::p <<
262 //! } <<
263 //! // We again create a ` 258 //! // We again create a `DropGuard`.
264 //! let __x_guard = unsafe !! 259 //! let x = &unsafe {
265 //! ::kernel::init::__ !! 260 //! ::kernel::init::__internal::DropGuard::new(
>> 261 //! ::core::addr_of_mut!((*slot).x),
>> 262 //! )
266 //! }; 263 //! };
267 //! // Since initializatio !! 264 //!
268 //! // the guards. This is <<
269 //! // `&DropGuard`. <<
270 //! ::core::mem::forget(__ <<
271 //! ::core::mem::forget(__ <<
272 //! // Here we use the typ 265 //! // Here we use the type checker to ensure that every field has been
273 //! // initialized exactly 266 //! // initialized exactly once, since this is `if false` it will never get
274 //! // executed, but still 267 //! // executed, but still type-checked.
275 //! // Additionally we abu !! 268 //! // Additionally we abuse `slot` to automatically infer the correct type for
276 //! // for the struct. Thi !! 269 //! // the struct. This is also another check that every field is accessible
277 //! // accessible from thi !! 270 //! // from this scope.
278 //! #[allow(unreachable_co 271 //! #[allow(unreachable_code, clippy::diverging_sub_expression)]
279 //! let _ = || { !! 272 //! if false {
280 //! unsafe { 273 //! unsafe {
281 //! ::core::ptr::w 274 //! ::core::ptr::write(
282 //! slot, 275 //! slot,
283 //! Self { 276 //! Self {
284 //! // We !! 277 //! // We only care about typecheck finding every field here,
285 //! // her !! 278 //! // the expression does not matter, just conjure one using
286 //! // one !! 279 //! // `panic!()`:
287 //! t: ::c 280 //! t: ::core::panic!(),
288 //! x: ::c 281 //! x: ::core::panic!(),
289 //! }, 282 //! },
290 //! ); 283 //! );
291 //! }; 284 //! };
292 //! }; !! 285 //! }
>> 286 //! // Since initialization has successfully completed, we can now forget the
>> 287 //! // guards. This is not `mem::forget`, since we only have `&DropGuard`.
>> 288 //! unsafe { ::kernel::init::__internal::DropGuard::forget(t) };
>> 289 //! unsafe { ::kernel::init::__internal::DropGuard::forget(x) };
293 //! } 290 //! }
294 //! // We leave the scope abov 291 //! // We leave the scope above and gain access to the previously shadowed
295 //! // `__InitOk` that we need 292 //! // `__InitOk` that we need to return.
296 //! Ok(__InitOk) 293 //! Ok(__InitOk)
297 //! }); 294 //! });
298 //! // Change the return type from 295 //! // Change the return type from `__InitOk` to `()`.
299 //! let init = move | !! 296 //! let init = move |slot| -> ::core::result::Result<(), ::core::convert::Infallible> {
300 //! slot, <<
301 //! | -> ::core::result::Result<() <<
302 //! init(slot).map(|__InitOk| 297 //! init(slot).map(|__InitOk| ())
303 //! }; 298 //! };
304 //! // Construct the initializer. 299 //! // Construct the initializer.
305 //! let init = unsafe { 300 //! let init = unsafe {
306 //! ::kernel::init::pin_init_f !! 301 //! ::kernel::init::pin_init_from_closure::<_, ::core::convert::Infallible>(init)
307 //! _, <<
308 //! ::core::convert::Infal <<
309 //! >(init) <<
310 //! }; 302 //! };
311 //! init 303 //! init
312 //! } 304 //! }
313 //! } 305 //! }
314 //! } 306 //! }
315 //! ``` 307 //! ```
316 //! 308 //!
317 //! ## `#[pin_data]` on `Foo` 309 //! ## `#[pin_data]` on `Foo`
318 //! 310 //!
319 //! Since we already took a look at `#[pin_dat 311 //! 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 312 //! differences/new things in the expansion of the `Foo` definition:
321 //! 313 //!
322 //! ```rust,ignore 314 //! ```rust,ignore
323 //! #[pin_data(PinnedDrop)] 315 //! #[pin_data(PinnedDrop)]
324 //! struct Foo { 316 //! struct Foo {
325 //! a: usize, 317 //! a: usize,
326 //! #[pin] 318 //! #[pin]
327 //! b: Bar<u32>, 319 //! b: Bar<u32>,
328 //! } 320 //! }
329 //! ``` 321 //! ```
330 //! 322 //!
331 //! This expands to the following code: 323 //! This expands to the following code:
332 //! 324 //!
333 //! ```rust,ignore 325 //! ```rust,ignore
334 //! struct Foo { 326 //! struct Foo {
335 //! a: usize, 327 //! a: usize,
336 //! b: Bar<u32>, 328 //! b: Bar<u32>,
337 //! } 329 //! }
338 //! const _: () = { 330 //! const _: () = {
339 //! struct __ThePinData { 331 //! struct __ThePinData {
340 //! __phantom: ::core::marker::Phantom 332 //! __phantom: ::core::marker::PhantomData<fn(Foo) -> Foo>,
341 //! } 333 //! }
342 //! impl ::core::clone::Clone for __ThePin 334 //! impl ::core::clone::Clone for __ThePinData {
343 //! fn clone(&self) -> Self { 335 //! fn clone(&self) -> Self {
344 //! *self 336 //! *self
345 //! } 337 //! }
346 //! } 338 //! }
347 //! impl ::core::marker::Copy for __ThePin 339 //! impl ::core::marker::Copy for __ThePinData {}
348 //! #[allow(dead_code)] 340 //! #[allow(dead_code)]
349 //! impl __ThePinData { 341 //! impl __ThePinData {
350 //! unsafe fn b<E>( 342 //! unsafe fn b<E>(
351 //! self, 343 //! self,
352 //! slot: *mut Bar<u32>, 344 //! slot: *mut Bar<u32>,
353 //! init: impl ::kernel::init::Pin 345 //! init: impl ::kernel::init::PinInit<Bar<u32>, E>,
354 //! ) -> ::core::result::Result<(), E> 346 //! ) -> ::core::result::Result<(), E> {
355 //! unsafe { ::kernel::init::PinIn 347 //! unsafe { ::kernel::init::PinInit::__pinned_init(init, slot) }
356 //! } 348 //! }
357 //! unsafe fn a<E>( 349 //! unsafe fn a<E>(
358 //! self, 350 //! self,
359 //! slot: *mut usize, 351 //! slot: *mut usize,
360 //! init: impl ::kernel::init::Ini 352 //! init: impl ::kernel::init::Init<usize, E>,
361 //! ) -> ::core::result::Result<(), E> 353 //! ) -> ::core::result::Result<(), E> {
362 //! unsafe { ::kernel::init::Init: 354 //! unsafe { ::kernel::init::Init::__init(init, slot) }
363 //! } 355 //! }
364 //! } 356 //! }
365 //! unsafe impl ::kernel::init::__internal 357 //! unsafe impl ::kernel::init::__internal::HasPinData for Foo {
366 //! type PinData = __ThePinData; 358 //! type PinData = __ThePinData;
367 //! unsafe fn __pin_data() -> Self::Pi 359 //! unsafe fn __pin_data() -> Self::PinData {
368 //! __ThePinData { 360 //! __ThePinData {
369 //! __phantom: ::core::marker: 361 //! __phantom: ::core::marker::PhantomData,
370 //! } 362 //! }
371 //! } 363 //! }
372 //! } 364 //! }
373 //! unsafe impl ::kernel::init::__internal 365 //! unsafe impl ::kernel::init::__internal::PinData for __ThePinData {
374 //! type Datee = Foo; 366 //! type Datee = Foo;
375 //! } 367 //! }
376 //! #[allow(dead_code)] 368 //! #[allow(dead_code)]
377 //! struct __Unpin<'__pin> { 369 //! struct __Unpin<'__pin> {
378 //! __phantom_pin: ::core::marker::Pha 370 //! __phantom_pin: ::core::marker::PhantomData<fn(&'__pin ()) -> &'__pin ()>,
379 //! __phantom: ::core::marker::Phantom 371 //! __phantom: ::core::marker::PhantomData<fn(Foo) -> Foo>,
380 //! b: Bar<u32>, 372 //! b: Bar<u32>,
381 //! } 373 //! }
382 //! #[doc(hidden)] 374 //! #[doc(hidden)]
383 //! impl<'__pin> ::core::marker::Unpin for !! 375 //! 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 376 //! // Since we specified `PinnedDrop` as the argument to `#[pin_data]`, we expect `Foo` to
388 //! // implement `PinnedDrop`. Thus we do 377 //! // implement `PinnedDrop`. Thus we do not need to prevent `Drop` implementations like
389 //! // before, instead we implement `Drop` 378 //! // before, instead we implement `Drop` here and delegate to `PinnedDrop`.
390 //! impl ::core::ops::Drop for Foo { 379 //! impl ::core::ops::Drop for Foo {
391 //! fn drop(&mut self) { 380 //! fn drop(&mut self) {
392 //! // Since we are getting droppe 381 //! // Since we are getting dropped, no one else has a reference to `self` and thus we
393 //! // can assume that we never mo 382 //! // can assume that we never move.
394 //! let pinned = unsafe { ::core:: 383 //! let pinned = unsafe { ::core::pin::Pin::new_unchecked(self) };
395 //! // Create the unsafe token tha 384 //! // Create the unsafe token that proves that we are inside of a destructor, this
396 //! // type is only allowed to be 385 //! // type is only allowed to be created in a destructor.
397 //! let token = unsafe { ::kernel: 386 //! let token = unsafe { ::kernel::init::__internal::OnlyCallFromDrop::new() };
398 //! ::kernel::init::PinnedDrop::dr 387 //! ::kernel::init::PinnedDrop::drop(pinned, token);
399 //! } 388 //! }
400 //! } 389 //! }
401 //! }; 390 //! };
402 //! ``` 391 //! ```
403 //! 392 //!
404 //! ## `#[pinned_drop]` on `impl PinnedDrop fo 393 //! ## `#[pinned_drop]` on `impl PinnedDrop for Foo`
405 //! 394 //!
406 //! This macro is used to implement the `Pinne 395 //! 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 396 //! extra parameter that should not be used at all. The macro hides that parameter.
408 //! 397 //!
409 //! Here is the `PinnedDrop` impl for `Foo`: 398 //! Here is the `PinnedDrop` impl for `Foo`:
410 //! 399 //!
411 //! ```rust,ignore 400 //! ```rust,ignore
412 //! #[pinned_drop] 401 //! #[pinned_drop]
413 //! impl PinnedDrop for Foo { 402 //! impl PinnedDrop for Foo {
414 //! fn drop(self: Pin<&mut Self>) { 403 //! fn drop(self: Pin<&mut Self>) {
415 //! pr_info!("{self:p} is getting drop !! 404 //! println!("{self:p} is getting dropped.");
416 //! } 405 //! }
417 //! } 406 //! }
418 //! ``` 407 //! ```
419 //! 408 //!
420 //! This expands to the following code: 409 //! This expands to the following code:
421 //! 410 //!
422 //! ```rust,ignore 411 //! ```rust,ignore
423 //! // `unsafe`, full path and the token param 412 //! // `unsafe`, full path and the token parameter are added, everything else stays the same.
424 //! unsafe impl ::kernel::init::PinnedDrop for 413 //! unsafe impl ::kernel::init::PinnedDrop for Foo {
425 //! fn drop(self: Pin<&mut Self>, _: ::ker 414 //! fn drop(self: Pin<&mut Self>, _: ::kernel::init::__internal::OnlyCallFromDrop) {
426 //! pr_info!("{self:p} is getting drop !! 415 //! println!("{self:p} is getting dropped.");
427 //! } 416 //! }
428 //! } 417 //! }
429 //! ``` 418 //! ```
430 //! 419 //!
431 //! ## `pin_init!` on `Foo` 420 //! ## `pin_init!` on `Foo`
432 //! 421 //!
433 //! Since we already took a look at `pin_init! 422 //! Since we already took a look at `pin_init!` on `Bar`, this section will only show the expansion
434 //! of `pin_init!` on `Foo`: 423 //! of `pin_init!` on `Foo`:
435 //! 424 //!
436 //! ```rust,ignore 425 //! ```rust,ignore
437 //! let a = 42; 426 //! let a = 42;
438 //! let initializer = pin_init!(Foo { 427 //! let initializer = pin_init!(Foo {
439 //! a, 428 //! a,
440 //! b <- Bar::new(36), 429 //! b <- Bar::new(36),
441 //! }); 430 //! });
442 //! ``` 431 //! ```
443 //! 432 //!
444 //! This expands to the following code: 433 //! This expands to the following code:
445 //! 434 //!
446 //! ```rust,ignore 435 //! ```rust,ignore
447 //! let a = 42; 436 //! let a = 42;
448 //! let initializer = { 437 //! let initializer = {
449 //! struct __InitOk; 438 //! struct __InitOk;
450 //! let data = unsafe { 439 //! let data = unsafe {
451 //! use ::kernel::init::__internal::Ha 440 //! use ::kernel::init::__internal::HasPinData;
452 //! Foo::__pin_data() 441 //! Foo::__pin_data()
453 //! }; 442 //! };
454 //! let init = ::kernel::init::__internal: 443 //! let init = ::kernel::init::__internal::PinData::make_closure::<
455 //! _, 444 //! _,
456 //! __InitOk, 445 //! __InitOk,
457 //! ::core::convert::Infallible, 446 //! ::core::convert::Infallible,
458 //! >(data, move |slot| { 447 //! >(data, move |slot| {
459 //! { 448 //! {
460 //! struct __InitOk; 449 //! struct __InitOk;
461 //! { !! 450 //! unsafe { ::core::ptr::write(::core::addr_of_mut!((*slot).a), a) };
462 //! unsafe { ::core::ptr::writ !! 451 //! let a = &unsafe {
463 //! } <<
464 //! let __a_guard = unsafe { <<
465 //! ::kernel::init::__internal 452 //! ::kernel::init::__internal::DropGuard::new(::core::addr_of_mut!((*slot).a))
466 //! }; 453 //! };
467 //! let init = Bar::new(36); !! 454 //! let b = Bar::new(36);
468 //! unsafe { data.b(::core::addr_o 455 //! unsafe { data.b(::core::addr_of_mut!((*slot).b), b)? };
469 //! let __b_guard = unsafe { !! 456 //! let b = &unsafe {
470 //! ::kernel::init::__internal 457 //! ::kernel::init::__internal::DropGuard::new(::core::addr_of_mut!((*slot).b))
471 //! }; 458 //! };
472 //! ::core::mem::forget(__b_guard) !! 459 //!
473 //! ::core::mem::forget(__a_guard) <<
474 //! #[allow(unreachable_code, clip 460 //! #[allow(unreachable_code, clippy::diverging_sub_expression)]
475 //! let _ = || { !! 461 //! if false {
476 //! unsafe { 462 //! unsafe {
477 //! ::core::ptr::write( 463 //! ::core::ptr::write(
478 //! slot, 464 //! slot,
479 //! Foo { 465 //! Foo {
480 //! a: ::core::pan 466 //! a: ::core::panic!(),
481 //! b: ::core::pan 467 //! b: ::core::panic!(),
482 //! }, 468 //! },
483 //! ); 469 //! );
484 //! }; 470 //! };
485 //! }; !! 471 //! }
>> 472 //! unsafe { ::kernel::init::__internal::DropGuard::forget(a) };
>> 473 //! unsafe { ::kernel::init::__internal::DropGuard::forget(b) };
486 //! } 474 //! }
487 //! Ok(__InitOk) 475 //! Ok(__InitOk)
488 //! }); 476 //! });
489 //! let init = move | !! 477 //! let init = move |slot| -> ::core::result::Result<(), ::core::convert::Infallible> {
490 //! slot, <<
491 //! | -> ::core::result::Result<(), ::core <<
492 //! init(slot).map(|__InitOk| ()) 478 //! init(slot).map(|__InitOk| ())
493 //! }; 479 //! };
494 //! let init = unsafe { 480 //! let init = unsafe {
495 //! ::kernel::init::pin_init_from_clos 481 //! ::kernel::init::pin_init_from_closure::<_, ::core::convert::Infallible>(init)
496 //! }; 482 //! };
497 //! init 483 //! init
498 //! }; 484 //! };
499 //! ``` 485 //! ```
500 486
501 /// Creates a `unsafe impl<...> PinnedDrop for 487 /// Creates a `unsafe impl<...> PinnedDrop for $type` block.
502 /// 488 ///
503 /// See [`PinnedDrop`] for more information. 489 /// See [`PinnedDrop`] for more information.
504 #[doc(hidden)] 490 #[doc(hidden)]
505 #[macro_export] 491 #[macro_export]
506 macro_rules! __pinned_drop { 492 macro_rules! __pinned_drop {
507 ( 493 (
508 @impl_sig($($impl_sig:tt)*), 494 @impl_sig($($impl_sig:tt)*),
509 @impl_body( 495 @impl_body(
510 $(#[$($attr:tt)*])* 496 $(#[$($attr:tt)*])*
511 fn drop($($sig:tt)*) { 497 fn drop($($sig:tt)*) {
512 $($inner:tt)* 498 $($inner:tt)*
513 } 499 }
514 ), 500 ),
515 ) => { 501 ) => {
516 unsafe $($impl_sig)* { 502 unsafe $($impl_sig)* {
517 // Inherit all attributes and the 503 // Inherit all attributes and the type/ident tokens for the signature.
518 $(#[$($attr)*])* 504 $(#[$($attr)*])*
519 fn drop($($sig)*, _: $crate::init: 505 fn drop($($sig)*, _: $crate::init::__internal::OnlyCallFromDrop) {
520 $($inner)* 506 $($inner)*
521 } 507 }
522 } 508 }
523 } 509 }
524 } 510 }
525 511
526 /// This macro first parses the struct definit 512 /// This macro first parses the struct definition such that it separates pinned and not pinned
527 /// fields. Afterwards it declares the struct 513 /// fields. Afterwards it declares the struct and implement the `PinData` trait safely.
528 #[doc(hidden)] 514 #[doc(hidden)]
529 #[macro_export] 515 #[macro_export]
530 macro_rules! __pin_data { 516 macro_rules! __pin_data {
531 // Proc-macro entry point, this is supplie 517 // Proc-macro entry point, this is supplied by the proc-macro pre-parsing.
532 (parse_input: 518 (parse_input:
533 @args($($pinned_drop:ident)?), 519 @args($($pinned_drop:ident)?),
534 @sig( 520 @sig(
535 $(#[$($struct_attr:tt)*])* 521 $(#[$($struct_attr:tt)*])*
536 $vis:vis struct $name:ident 522 $vis:vis struct $name:ident
537 $(where $($whr:tt)*)? 523 $(where $($whr:tt)*)?
538 ), 524 ),
539 @impl_generics($($impl_generics:tt)*), 525 @impl_generics($($impl_generics:tt)*),
540 @ty_generics($($ty_generics:tt)*), 526 @ty_generics($($ty_generics:tt)*),
541 @decl_generics($($decl_generics:tt)*), <<
542 @body({ $($fields:tt)* }), 527 @body({ $($fields:tt)* }),
543 ) => { 528 ) => {
544 // We now use token munching to iterat 529 // We now use token munching to iterate through all of the fields. While doing this we
545 // identify fields marked with `#[pin] 530 // identify fields marked with `#[pin]`, these fields are the 'pinned fields'. The user
546 // wants these to be structurally pinn 531 // wants these to be structurally pinned. The rest of the fields are the
547 // 'not pinned fields'. Additionally w 532 // 'not pinned fields'. Additionally we collect all fields, since we need them in the right
548 // order to declare the struct. 533 // order to declare the struct.
549 // 534 //
550 // In this call we also put some expla 535 // In this call we also put some explaining comments for the parameters.
551 $crate::__pin_data!(find_pinned_fields 536 $crate::__pin_data!(find_pinned_fields:
552 // Attributes on the struct itself 537 // Attributes on the struct itself, these will just be propagated to be put onto the
553 // struct definition. 538 // struct definition.
554 @struct_attrs($(#[$($struct_attr)* 539 @struct_attrs($(#[$($struct_attr)*])*),
555 // The visibility of the struct. 540 // The visibility of the struct.
556 @vis($vis), 541 @vis($vis),
557 // The name of the struct. 542 // The name of the struct.
558 @name($name), 543 @name($name),
559 // The 'impl generics', the generi 544 // The 'impl generics', the generics that will need to be specified on the struct inside
560 // of an `impl<$ty_generics>` bloc 545 // of an `impl<$ty_generics>` block.
561 @impl_generics($($impl_generics)*) 546 @impl_generics($($impl_generics)*),
562 // The 'ty generics', the generics 547 // The 'ty generics', the generics that will need to be specified on the impl blocks.
563 @ty_generics($($ty_generics)*), 548 @ty_generics($($ty_generics)*),
564 // The 'decl generics', the generi <<
565 // definition. <<
566 @decl_generics($($decl_generics)*) <<
567 // The where clause of any impl bl 549 // The where clause of any impl block and the declaration.
568 @where($($($whr)*)?), 550 @where($($($whr)*)?),
569 // The remaining fields tokens tha 551 // The remaining fields tokens that need to be processed.
570 // We add a `,` at the end to ensu 552 // We add a `,` at the end to ensure correct parsing.
571 @fields_munch($($fields)* ,), 553 @fields_munch($($fields)* ,),
572 // The pinned fields. 554 // The pinned fields.
573 @pinned(), 555 @pinned(),
574 // The not pinned fields. 556 // The not pinned fields.
575 @not_pinned(), 557 @not_pinned(),
576 // All fields. 558 // All fields.
577 @fields(), 559 @fields(),
578 // The accumulator containing all 560 // The accumulator containing all attributes already parsed.
579 @accum(), 561 @accum(),
580 // Contains `yes` or `` to indicat 562 // Contains `yes` or `` to indicate if `#[pin]` was found on the current field.
581 @is_pinned(), 563 @is_pinned(),
582 // The proc-macro argument, this s 564 // The proc-macro argument, this should be `PinnedDrop` or ``.
583 @pinned_drop($($pinned_drop)?), 565 @pinned_drop($($pinned_drop)?),
584 ); 566 );
585 }; 567 };
586 (find_pinned_fields: 568 (find_pinned_fields:
587 @struct_attrs($($struct_attrs:tt)*), 569 @struct_attrs($($struct_attrs:tt)*),
588 @vis($vis:vis), 570 @vis($vis:vis),
589 @name($name:ident), 571 @name($name:ident),
590 @impl_generics($($impl_generics:tt)*), 572 @impl_generics($($impl_generics:tt)*),
591 @ty_generics($($ty_generics:tt)*), 573 @ty_generics($($ty_generics:tt)*),
592 @decl_generics($($decl_generics:tt)*), <<
593 @where($($whr:tt)*), 574 @where($($whr:tt)*),
594 // We found a PhantomPinned field, thi 575 // We found a PhantomPinned field, this should generally be pinned!
595 @fields_munch($field:ident : $($($(::) 576 @fields_munch($field:ident : $($($(::)?core::)?marker::)?PhantomPinned, $($rest:tt)*),
596 @pinned($($pinned:tt)*), 577 @pinned($($pinned:tt)*),
597 @not_pinned($($not_pinned:tt)*), 578 @not_pinned($($not_pinned:tt)*),
598 @fields($($fields:tt)*), 579 @fields($($fields:tt)*),
599 @accum($($accum:tt)*), 580 @accum($($accum:tt)*),
600 // This field is not pinned. 581 // This field is not pinned.
601 @is_pinned(), 582 @is_pinned(),
602 @pinned_drop($($pinned_drop:ident)?), 583 @pinned_drop($($pinned_drop:ident)?),
603 ) => { 584 ) => {
604 ::core::compile_error!(concat!( 585 ::core::compile_error!(concat!(
605 "The field `", 586 "The field `",
606 stringify!($field), 587 stringify!($field),
607 "` of type `PhantomPinned` only ha 588 "` of type `PhantomPinned` only has an effect, if it has the `#[pin]` attribute.",
608 )); 589 ));
609 $crate::__pin_data!(find_pinned_fields 590 $crate::__pin_data!(find_pinned_fields:
610 @struct_attrs($($struct_attrs)*), 591 @struct_attrs($($struct_attrs)*),
611 @vis($vis), 592 @vis($vis),
612 @name($name), 593 @name($name),
613 @impl_generics($($impl_generics)*) 594 @impl_generics($($impl_generics)*),
614 @ty_generics($($ty_generics)*), 595 @ty_generics($($ty_generics)*),
615 @decl_generics($($decl_generics)*) <<
616 @where($($whr)*), 596 @where($($whr)*),
617 @fields_munch($($rest)*), 597 @fields_munch($($rest)*),
618 @pinned($($pinned)* $($accum)* $fi 598 @pinned($($pinned)* $($accum)* $field: ::core::marker::PhantomPinned,),
619 @not_pinned($($not_pinned)*), 599 @not_pinned($($not_pinned)*),
620 @fields($($fields)* $($accum)* $fi 600 @fields($($fields)* $($accum)* $field: ::core::marker::PhantomPinned,),
621 @accum(), 601 @accum(),
622 @is_pinned(), 602 @is_pinned(),
623 @pinned_drop($($pinned_drop)?), 603 @pinned_drop($($pinned_drop)?),
624 ); 604 );
625 }; 605 };
626 (find_pinned_fields: 606 (find_pinned_fields:
627 @struct_attrs($($struct_attrs:tt)*), 607 @struct_attrs($($struct_attrs:tt)*),
628 @vis($vis:vis), 608 @vis($vis:vis),
629 @name($name:ident), 609 @name($name:ident),
630 @impl_generics($($impl_generics:tt)*), 610 @impl_generics($($impl_generics:tt)*),
631 @ty_generics($($ty_generics:tt)*), 611 @ty_generics($($ty_generics:tt)*),
632 @decl_generics($($decl_generics:tt)*), <<
633 @where($($whr:tt)*), 612 @where($($whr:tt)*),
634 // We reached the field declaration. 613 // We reached the field declaration.
635 @fields_munch($field:ident : $type:ty, 614 @fields_munch($field:ident : $type:ty, $($rest:tt)*),
636 @pinned($($pinned:tt)*), 615 @pinned($($pinned:tt)*),
637 @not_pinned($($not_pinned:tt)*), 616 @not_pinned($($not_pinned:tt)*),
638 @fields($($fields:tt)*), 617 @fields($($fields:tt)*),
639 @accum($($accum:tt)*), 618 @accum($($accum:tt)*),
640 // This field is pinned. 619 // This field is pinned.
641 @is_pinned(yes), 620 @is_pinned(yes),
642 @pinned_drop($($pinned_drop:ident)?), 621 @pinned_drop($($pinned_drop:ident)?),
643 ) => { 622 ) => {
644 $crate::__pin_data!(find_pinned_fields 623 $crate::__pin_data!(find_pinned_fields:
645 @struct_attrs($($struct_attrs)*), 624 @struct_attrs($($struct_attrs)*),
646 @vis($vis), 625 @vis($vis),
647 @name($name), 626 @name($name),
648 @impl_generics($($impl_generics)*) 627 @impl_generics($($impl_generics)*),
649 @ty_generics($($ty_generics)*), 628 @ty_generics($($ty_generics)*),
650 @decl_generics($($decl_generics)*) <<
651 @where($($whr)*), 629 @where($($whr)*),
652 @fields_munch($($rest)*), 630 @fields_munch($($rest)*),
653 @pinned($($pinned)* $($accum)* $fi 631 @pinned($($pinned)* $($accum)* $field: $type,),
654 @not_pinned($($not_pinned)*), 632 @not_pinned($($not_pinned)*),
655 @fields($($fields)* $($accum)* $fi 633 @fields($($fields)* $($accum)* $field: $type,),
656 @accum(), 634 @accum(),
657 @is_pinned(), 635 @is_pinned(),
658 @pinned_drop($($pinned_drop)?), 636 @pinned_drop($($pinned_drop)?),
659 ); 637 );
660 }; 638 };
661 (find_pinned_fields: 639 (find_pinned_fields:
662 @struct_attrs($($struct_attrs:tt)*), 640 @struct_attrs($($struct_attrs:tt)*),
663 @vis($vis:vis), 641 @vis($vis:vis),
664 @name($name:ident), 642 @name($name:ident),
665 @impl_generics($($impl_generics:tt)*), 643 @impl_generics($($impl_generics:tt)*),
666 @ty_generics($($ty_generics:tt)*), 644 @ty_generics($($ty_generics:tt)*),
667 @decl_generics($($decl_generics:tt)*), <<
668 @where($($whr:tt)*), 645 @where($($whr:tt)*),
669 // We reached the field declaration. 646 // We reached the field declaration.
670 @fields_munch($field:ident : $type:ty, 647 @fields_munch($field:ident : $type:ty, $($rest:tt)*),
671 @pinned($($pinned:tt)*), 648 @pinned($($pinned:tt)*),
672 @not_pinned($($not_pinned:tt)*), 649 @not_pinned($($not_pinned:tt)*),
673 @fields($($fields:tt)*), 650 @fields($($fields:tt)*),
674 @accum($($accum:tt)*), 651 @accum($($accum:tt)*),
675 // This field is not pinned. 652 // This field is not pinned.
676 @is_pinned(), 653 @is_pinned(),
677 @pinned_drop($($pinned_drop:ident)?), 654 @pinned_drop($($pinned_drop:ident)?),
678 ) => { 655 ) => {
679 $crate::__pin_data!(find_pinned_fields 656 $crate::__pin_data!(find_pinned_fields:
680 @struct_attrs($($struct_attrs)*), 657 @struct_attrs($($struct_attrs)*),
681 @vis($vis), 658 @vis($vis),
682 @name($name), 659 @name($name),
683 @impl_generics($($impl_generics)*) 660 @impl_generics($($impl_generics)*),
684 @ty_generics($($ty_generics)*), 661 @ty_generics($($ty_generics)*),
685 @decl_generics($($decl_generics)*) <<
686 @where($($whr)*), 662 @where($($whr)*),
687 @fields_munch($($rest)*), 663 @fields_munch($($rest)*),
688 @pinned($($pinned)*), 664 @pinned($($pinned)*),
689 @not_pinned($($not_pinned)* $($acc 665 @not_pinned($($not_pinned)* $($accum)* $field: $type,),
690 @fields($($fields)* $($accum)* $fi 666 @fields($($fields)* $($accum)* $field: $type,),
691 @accum(), 667 @accum(),
692 @is_pinned(), 668 @is_pinned(),
693 @pinned_drop($($pinned_drop)?), 669 @pinned_drop($($pinned_drop)?),
694 ); 670 );
695 }; 671 };
696 (find_pinned_fields: 672 (find_pinned_fields:
697 @struct_attrs($($struct_attrs:tt)*), 673 @struct_attrs($($struct_attrs:tt)*),
698 @vis($vis:vis), 674 @vis($vis:vis),
699 @name($name:ident), 675 @name($name:ident),
700 @impl_generics($($impl_generics:tt)*), 676 @impl_generics($($impl_generics:tt)*),
701 @ty_generics($($ty_generics:tt)*), 677 @ty_generics($($ty_generics:tt)*),
702 @decl_generics($($decl_generics:tt)*), <<
703 @where($($whr:tt)*), 678 @where($($whr:tt)*),
704 // We found the `#[pin]` attr. 679 // We found the `#[pin]` attr.
705 @fields_munch(#[pin] $($rest:tt)*), 680 @fields_munch(#[pin] $($rest:tt)*),
706 @pinned($($pinned:tt)*), 681 @pinned($($pinned:tt)*),
707 @not_pinned($($not_pinned:tt)*), 682 @not_pinned($($not_pinned:tt)*),
708 @fields($($fields:tt)*), 683 @fields($($fields:tt)*),
709 @accum($($accum:tt)*), 684 @accum($($accum:tt)*),
710 @is_pinned($($is_pinned:ident)?), 685 @is_pinned($($is_pinned:ident)?),
711 @pinned_drop($($pinned_drop:ident)?), 686 @pinned_drop($($pinned_drop:ident)?),
712 ) => { 687 ) => {
713 $crate::__pin_data!(find_pinned_fields 688 $crate::__pin_data!(find_pinned_fields:
714 @struct_attrs($($struct_attrs)*), 689 @struct_attrs($($struct_attrs)*),
715 @vis($vis), 690 @vis($vis),
716 @name($name), 691 @name($name),
717 @impl_generics($($impl_generics)*) 692 @impl_generics($($impl_generics)*),
718 @ty_generics($($ty_generics)*), 693 @ty_generics($($ty_generics)*),
719 @decl_generics($($decl_generics)*) <<
720 @where($($whr)*), 694 @where($($whr)*),
721 @fields_munch($($rest)*), 695 @fields_munch($($rest)*),
722 // We do not include `#[pin]` in t 696 // We do not include `#[pin]` in the list of attributes, since it is not actually an
723 // attribute that is defined somew 697 // attribute that is defined somewhere.
724 @pinned($($pinned)*), 698 @pinned($($pinned)*),
725 @not_pinned($($not_pinned)*), 699 @not_pinned($($not_pinned)*),
726 @fields($($fields)*), 700 @fields($($fields)*),
727 @accum($($accum)*), 701 @accum($($accum)*),
728 // Set this to `yes`. 702 // Set this to `yes`.
729 @is_pinned(yes), 703 @is_pinned(yes),
730 @pinned_drop($($pinned_drop)?), 704 @pinned_drop($($pinned_drop)?),
731 ); 705 );
732 }; 706 };
733 (find_pinned_fields: 707 (find_pinned_fields:
734 @struct_attrs($($struct_attrs:tt)*), 708 @struct_attrs($($struct_attrs:tt)*),
735 @vis($vis:vis), 709 @vis($vis:vis),
736 @name($name:ident), 710 @name($name:ident),
737 @impl_generics($($impl_generics:tt)*), 711 @impl_generics($($impl_generics:tt)*),
738 @ty_generics($($ty_generics:tt)*), 712 @ty_generics($($ty_generics:tt)*),
739 @decl_generics($($decl_generics:tt)*), <<
740 @where($($whr:tt)*), 713 @where($($whr:tt)*),
741 // We reached the field declaration wi 714 // We reached the field declaration with visibility, for simplicity we only munch the
742 // visibility and put it into `$accum` 715 // visibility and put it into `$accum`.
743 @fields_munch($fvis:vis $field:ident $ 716 @fields_munch($fvis:vis $field:ident $($rest:tt)*),
744 @pinned($($pinned:tt)*), 717 @pinned($($pinned:tt)*),
745 @not_pinned($($not_pinned:tt)*), 718 @not_pinned($($not_pinned:tt)*),
746 @fields($($fields:tt)*), 719 @fields($($fields:tt)*),
747 @accum($($accum:tt)*), 720 @accum($($accum:tt)*),
748 @is_pinned($($is_pinned:ident)?), 721 @is_pinned($($is_pinned:ident)?),
749 @pinned_drop($($pinned_drop:ident)?), 722 @pinned_drop($($pinned_drop:ident)?),
750 ) => { 723 ) => {
751 $crate::__pin_data!(find_pinned_fields 724 $crate::__pin_data!(find_pinned_fields:
752 @struct_attrs($($struct_attrs)*), 725 @struct_attrs($($struct_attrs)*),
753 @vis($vis), 726 @vis($vis),
754 @name($name), 727 @name($name),
755 @impl_generics($($impl_generics)*) 728 @impl_generics($($impl_generics)*),
756 @ty_generics($($ty_generics)*), 729 @ty_generics($($ty_generics)*),
757 @decl_generics($($decl_generics)*) <<
758 @where($($whr)*), 730 @where($($whr)*),
759 @fields_munch($field $($rest)*), 731 @fields_munch($field $($rest)*),
760 @pinned($($pinned)*), 732 @pinned($($pinned)*),
761 @not_pinned($($not_pinned)*), 733 @not_pinned($($not_pinned)*),
762 @fields($($fields)*), 734 @fields($($fields)*),
763 @accum($($accum)* $fvis), 735 @accum($($accum)* $fvis),
764 @is_pinned($($is_pinned)?), 736 @is_pinned($($is_pinned)?),
765 @pinned_drop($($pinned_drop)?), 737 @pinned_drop($($pinned_drop)?),
766 ); 738 );
767 }; 739 };
768 (find_pinned_fields: 740 (find_pinned_fields:
769 @struct_attrs($($struct_attrs:tt)*), 741 @struct_attrs($($struct_attrs:tt)*),
770 @vis($vis:vis), 742 @vis($vis:vis),
771 @name($name:ident), 743 @name($name:ident),
772 @impl_generics($($impl_generics:tt)*), 744 @impl_generics($($impl_generics:tt)*),
773 @ty_generics($($ty_generics:tt)*), 745 @ty_generics($($ty_generics:tt)*),
774 @decl_generics($($decl_generics:tt)*), <<
775 @where($($whr:tt)*), 746 @where($($whr:tt)*),
776 // Some other attribute, just put it i 747 // Some other attribute, just put it into `$accum`.
777 @fields_munch(#[$($attr:tt)*] $($rest: 748 @fields_munch(#[$($attr:tt)*] $($rest:tt)*),
778 @pinned($($pinned:tt)*), 749 @pinned($($pinned:tt)*),
779 @not_pinned($($not_pinned:tt)*), 750 @not_pinned($($not_pinned:tt)*),
780 @fields($($fields:tt)*), 751 @fields($($fields:tt)*),
781 @accum($($accum:tt)*), 752 @accum($($accum:tt)*),
782 @is_pinned($($is_pinned:ident)?), 753 @is_pinned($($is_pinned:ident)?),
783 @pinned_drop($($pinned_drop:ident)?), 754 @pinned_drop($($pinned_drop:ident)?),
784 ) => { 755 ) => {
785 $crate::__pin_data!(find_pinned_fields 756 $crate::__pin_data!(find_pinned_fields:
786 @struct_attrs($($struct_attrs)*), 757 @struct_attrs($($struct_attrs)*),
787 @vis($vis), 758 @vis($vis),
788 @name($name), 759 @name($name),
789 @impl_generics($($impl_generics)*) 760 @impl_generics($($impl_generics)*),
790 @ty_generics($($ty_generics)*), 761 @ty_generics($($ty_generics)*),
791 @decl_generics($($decl_generics)*) <<
792 @where($($whr)*), 762 @where($($whr)*),
793 @fields_munch($($rest)*), 763 @fields_munch($($rest)*),
794 @pinned($($pinned)*), 764 @pinned($($pinned)*),
795 @not_pinned($($not_pinned)*), 765 @not_pinned($($not_pinned)*),
796 @fields($($fields)*), 766 @fields($($fields)*),
797 @accum($($accum)* #[$($attr)*]), 767 @accum($($accum)* #[$($attr)*]),
798 @is_pinned($($is_pinned)?), 768 @is_pinned($($is_pinned)?),
799 @pinned_drop($($pinned_drop)?), 769 @pinned_drop($($pinned_drop)?),
800 ); 770 );
801 }; 771 };
802 (find_pinned_fields: 772 (find_pinned_fields:
803 @struct_attrs($($struct_attrs:tt)*), 773 @struct_attrs($($struct_attrs:tt)*),
804 @vis($vis:vis), 774 @vis($vis:vis),
805 @name($name:ident), 775 @name($name:ident),
806 @impl_generics($($impl_generics:tt)*), 776 @impl_generics($($impl_generics:tt)*),
807 @ty_generics($($ty_generics:tt)*), 777 @ty_generics($($ty_generics:tt)*),
808 @decl_generics($($decl_generics:tt)*), <<
809 @where($($whr:tt)*), 778 @where($($whr:tt)*),
810 // We reached the end of the fields, p 779 // We reached the end of the fields, plus an optional additional comma, since we added one
811 // before and the user is also allowed 780 // before and the user is also allowed to put a trailing comma.
812 @fields_munch($(,)?), 781 @fields_munch($(,)?),
813 @pinned($($pinned:tt)*), 782 @pinned($($pinned:tt)*),
814 @not_pinned($($not_pinned:tt)*), 783 @not_pinned($($not_pinned:tt)*),
815 @fields($($fields:tt)*), 784 @fields($($fields:tt)*),
816 @accum(), 785 @accum(),
817 @is_pinned(), 786 @is_pinned(),
818 @pinned_drop($($pinned_drop:ident)?), 787 @pinned_drop($($pinned_drop:ident)?),
819 ) => { 788 ) => {
820 // Declare the struct with all fields 789 // Declare the struct with all fields in the correct order.
821 $($struct_attrs)* 790 $($struct_attrs)*
822 $vis struct $name <$($decl_generics)*> !! 791 $vis struct $name <$($impl_generics)*>
823 where $($whr)* 792 where $($whr)*
824 { 793 {
825 $($fields)* 794 $($fields)*
826 } 795 }
827 796
828 // We put the rest into this const ite 797 // We put the rest into this const item, because it then will not be accessible to anything
829 // outside. 798 // outside.
830 const _: () = { 799 const _: () = {
831 // We declare this struct which wi 800 // We declare this struct which will host all of the projection function for our type.
832 // it will be invariant over all g 801 // it will be invariant over all generic parameters which are inherited from the
833 // struct. 802 // struct.
834 $vis struct __ThePinData<$($impl_g 803 $vis struct __ThePinData<$($impl_generics)*>
835 where $($whr)* 804 where $($whr)*
836 { 805 {
837 __phantom: ::core::marker::Pha 806 __phantom: ::core::marker::PhantomData<
838 fn($name<$($ty_generics)*> 807 fn($name<$($ty_generics)*>) -> $name<$($ty_generics)*>
839 >, 808 >,
840 } 809 }
841 810
842 impl<$($impl_generics)*> ::core::c 811 impl<$($impl_generics)*> ::core::clone::Clone for __ThePinData<$($ty_generics)*>
843 where $($whr)* 812 where $($whr)*
844 { 813 {
845 fn clone(&self) -> Self { *sel 814 fn clone(&self) -> Self { *self }
846 } 815 }
847 816
848 impl<$($impl_generics)*> ::core::m 817 impl<$($impl_generics)*> ::core::marker::Copy for __ThePinData<$($ty_generics)*>
849 where $($whr)* 818 where $($whr)*
850 {} 819 {}
851 820
852 // Make all projection functions. 821 // Make all projection functions.
853 $crate::__pin_data!(make_pin_data: 822 $crate::__pin_data!(make_pin_data:
854 @pin_data(__ThePinData), 823 @pin_data(__ThePinData),
855 @impl_generics($($impl_generic 824 @impl_generics($($impl_generics)*),
856 @ty_generics($($ty_generics)*) 825 @ty_generics($($ty_generics)*),
857 @where($($whr)*), 826 @where($($whr)*),
858 @pinned($($pinned)*), 827 @pinned($($pinned)*),
859 @not_pinned($($not_pinned)*), 828 @not_pinned($($not_pinned)*),
860 ); 829 );
861 830
862 // SAFETY: We have added the corre 831 // SAFETY: We have added the correct projection functions above to `__ThePinData` and
863 // we also use the least restricti 832 // we also use the least restrictive generics possible.
864 unsafe impl<$($impl_generics)*> 833 unsafe impl<$($impl_generics)*>
865 $crate::init::__internal::HasP 834 $crate::init::__internal::HasPinData for $name<$($ty_generics)*>
866 where $($whr)* 835 where $($whr)*
867 { 836 {
868 type PinData = __ThePinData<$( 837 type PinData = __ThePinData<$($ty_generics)*>;
869 838
870 unsafe fn __pin_data() -> Self 839 unsafe fn __pin_data() -> Self::PinData {
871 __ThePinData { __phantom: 840 __ThePinData { __phantom: ::core::marker::PhantomData }
872 } 841 }
873 } 842 }
874 843
875 unsafe impl<$($impl_generics)*> 844 unsafe impl<$($impl_generics)*>
876 $crate::init::__internal::PinD 845 $crate::init::__internal::PinData for __ThePinData<$($ty_generics)*>
877 where $($whr)* 846 where $($whr)*
878 { 847 {
879 type Datee = $name<$($ty_gener 848 type Datee = $name<$($ty_generics)*>;
880 } 849 }
881 850
882 // This struct will be used for th 851 // This struct will be used for the unpin analysis. Since only structurally pinned
883 // fields are relevant whether the 852 // fields are relevant whether the struct should implement `Unpin`.
884 #[allow(dead_code)] 853 #[allow(dead_code)]
885 struct __Unpin <'__pin, $($impl_ge 854 struct __Unpin <'__pin, $($impl_generics)*>
886 where $($whr)* 855 where $($whr)*
887 { 856 {
888 __phantom_pin: ::core::marker: 857 __phantom_pin: ::core::marker::PhantomData<fn(&'__pin ()) -> &'__pin ()>,
889 __phantom: ::core::marker::Pha 858 __phantom: ::core::marker::PhantomData<
890 fn($name<$($ty_generics)*> 859 fn($name<$($ty_generics)*>) -> $name<$($ty_generics)*>
891 >, 860 >,
892 // Only the pinned fields. 861 // Only the pinned fields.
893 $($pinned)* 862 $($pinned)*
894 } 863 }
895 864
896 #[doc(hidden)] 865 #[doc(hidden)]
897 impl<'__pin, $($impl_generics)*> : 866 impl<'__pin, $($impl_generics)*> ::core::marker::Unpin for $name<$($ty_generics)*>
898 where 867 where
899 __Unpin<'__pin, $($ty_generics 868 __Unpin<'__pin, $($ty_generics)*>: ::core::marker::Unpin,
900 $($whr)* 869 $($whr)*
901 {} 870 {}
902 871
903 // We need to disallow normal `Dro 872 // We need to disallow normal `Drop` implementation, the exact behavior depends on
904 // whether `PinnedDrop` was specif 873 // whether `PinnedDrop` was specified as the parameter.
905 $crate::__pin_data!(drop_preventio 874 $crate::__pin_data!(drop_prevention:
906 @name($name), 875 @name($name),
907 @impl_generics($($impl_generic 876 @impl_generics($($impl_generics)*),
908 @ty_generics($($ty_generics)*) 877 @ty_generics($($ty_generics)*),
909 @where($($whr)*), 878 @where($($whr)*),
910 @pinned_drop($($pinned_drop)?) 879 @pinned_drop($($pinned_drop)?),
911 ); 880 );
912 }; 881 };
913 }; 882 };
914 // When no `PinnedDrop` was specified, the 883 // When no `PinnedDrop` was specified, then we have to prevent implementing drop.
915 (drop_prevention: 884 (drop_prevention:
916 @name($name:ident), 885 @name($name:ident),
917 @impl_generics($($impl_generics:tt)*), 886 @impl_generics($($impl_generics:tt)*),
918 @ty_generics($($ty_generics:tt)*), 887 @ty_generics($($ty_generics:tt)*),
919 @where($($whr:tt)*), 888 @where($($whr:tt)*),
920 @pinned_drop(), 889 @pinned_drop(),
921 ) => { 890 ) => {
922 // We prevent this by creating a trait 891 // We prevent this by creating a trait that will be implemented for all types implementing
923 // `Drop`. Additionally we will implem 892 // `Drop`. Additionally we will implement this trait for the struct leading to a conflict,
924 // if it also implements `Drop` 893 // if it also implements `Drop`
925 trait MustNotImplDrop {} 894 trait MustNotImplDrop {}
926 #[allow(drop_bounds)] 895 #[allow(drop_bounds)]
927 impl<T: ::core::ops::Drop> MustNotImpl 896 impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
928 impl<$($impl_generics)*> MustNotImplDr 897 impl<$($impl_generics)*> MustNotImplDrop for $name<$($ty_generics)*>
929 where $($whr)* {} 898 where $($whr)* {}
930 // We also take care to prevent users 899 // We also take care to prevent users from writing a useless `PinnedDrop` implementation.
931 // They might implement `PinnedDrop` c 900 // They might implement `PinnedDrop` correctly for the struct, but forget to give
932 // `PinnedDrop` as the parameter to `# 901 // `PinnedDrop` as the parameter to `#[pin_data]`.
933 #[allow(non_camel_case_types)] 902 #[allow(non_camel_case_types)]
934 trait UselessPinnedDropImpl_you_need_t 903 trait UselessPinnedDropImpl_you_need_to_specify_PinnedDrop {}
935 impl<T: $crate::init::PinnedDrop> 904 impl<T: $crate::init::PinnedDrop>
936 UselessPinnedDropImpl_you_need_to_ 905 UselessPinnedDropImpl_you_need_to_specify_PinnedDrop for T {}
937 impl<$($impl_generics)*> 906 impl<$($impl_generics)*>
938 UselessPinnedDropImpl_you_need_to_ 907 UselessPinnedDropImpl_you_need_to_specify_PinnedDrop for $name<$($ty_generics)*>
939 where $($whr)* {} 908 where $($whr)* {}
940 }; 909 };
941 // When `PinnedDrop` was specified we just 910 // When `PinnedDrop` was specified we just implement `Drop` and delegate.
942 (drop_prevention: 911 (drop_prevention:
943 @name($name:ident), 912 @name($name:ident),
944 @impl_generics($($impl_generics:tt)*), 913 @impl_generics($($impl_generics:tt)*),
945 @ty_generics($($ty_generics:tt)*), 914 @ty_generics($($ty_generics:tt)*),
946 @where($($whr:tt)*), 915 @where($($whr:tt)*),
947 @pinned_drop(PinnedDrop), 916 @pinned_drop(PinnedDrop),
948 ) => { 917 ) => {
949 impl<$($impl_generics)*> ::core::ops:: 918 impl<$($impl_generics)*> ::core::ops::Drop for $name<$($ty_generics)*>
950 where $($whr)* 919 where $($whr)*
951 { 920 {
952 fn drop(&mut self) { 921 fn drop(&mut self) {
953 // SAFETY: Since this is a des 922 // SAFETY: Since this is a destructor, `self` will not move after this function
954 // terminates, since it is ina 923 // terminates, since it is inaccessible.
955 let pinned = unsafe { ::core:: 924 let pinned = unsafe { ::core::pin::Pin::new_unchecked(self) };
956 // SAFETY: Since this is a dro 925 // SAFETY: Since this is a drop function, we can create this token to call the
957 // pinned destructor of this t 926 // pinned destructor of this type.
958 let token = unsafe { $crate::i 927 let token = unsafe { $crate::init::__internal::OnlyCallFromDrop::new() };
959 $crate::init::PinnedDrop::drop 928 $crate::init::PinnedDrop::drop(pinned, token);
960 } 929 }
961 } 930 }
962 }; 931 };
963 // If some other parameter was specified, 932 // If some other parameter was specified, we emit a readable error.
964 (drop_prevention: 933 (drop_prevention:
965 @name($name:ident), 934 @name($name:ident),
966 @impl_generics($($impl_generics:tt)*), 935 @impl_generics($($impl_generics:tt)*),
967 @ty_generics($($ty_generics:tt)*), 936 @ty_generics($($ty_generics:tt)*),
968 @where($($whr:tt)*), 937 @where($($whr:tt)*),
969 @pinned_drop($($rest:tt)*), 938 @pinned_drop($($rest:tt)*),
970 ) => { 939 ) => {
971 compile_error!( 940 compile_error!(
972 "Wrong parameters to `#[pin_data]` 941 "Wrong parameters to `#[pin_data]`, expected nothing or `PinnedDrop`, got '{}'.",
973 stringify!($($rest)*), 942 stringify!($($rest)*),
974 ); 943 );
975 }; 944 };
976 (make_pin_data: 945 (make_pin_data:
977 @pin_data($pin_data:ident), 946 @pin_data($pin_data:ident),
978 @impl_generics($($impl_generics:tt)*), 947 @impl_generics($($impl_generics:tt)*),
979 @ty_generics($($ty_generics:tt)*), 948 @ty_generics($($ty_generics:tt)*),
980 @where($($whr:tt)*), 949 @where($($whr:tt)*),
981 @pinned($($(#[$($p_attr:tt)*])* $pvis: 950 @pinned($($(#[$($p_attr:tt)*])* $pvis:vis $p_field:ident : $p_type:ty),* $(,)?),
982 @not_pinned($($(#[$($attr:tt)*])* $fvi 951 @not_pinned($($(#[$($attr:tt)*])* $fvis:vis $field:ident : $type:ty),* $(,)?),
983 ) => { 952 ) => {
984 // For every field, we create a projec 953 // For every field, we create a projection function according to its projection type. If a
985 // field is structurally pinned, then 954 // field is structurally pinned, then it must be initialized via `PinInit`, if it is not
986 // structurally pinned, then it can be 955 // structurally pinned, then it can be initialized via `Init`.
987 // 956 //
988 // The functions are `unsafe` to preve 957 // The functions are `unsafe` to prevent accidentally calling them.
989 #[allow(dead_code)] 958 #[allow(dead_code)]
990 impl<$($impl_generics)*> $pin_data<$($ 959 impl<$($impl_generics)*> $pin_data<$($ty_generics)*>
991 where $($whr)* 960 where $($whr)*
992 { 961 {
993 $( 962 $(
994 $(#[$($p_attr)*])* <<
995 $pvis unsafe fn $p_field<E>( 963 $pvis unsafe fn $p_field<E>(
996 self, 964 self,
997 slot: *mut $p_type, 965 slot: *mut $p_type,
998 init: impl $crate::init::P 966 init: impl $crate::init::PinInit<$p_type, E>,
999 ) -> ::core::result::Result<() 967 ) -> ::core::result::Result<(), E> {
1000 unsafe { $crate::init::Pi 968 unsafe { $crate::init::PinInit::__pinned_init(init, slot) }
1001 } 969 }
1002 )* 970 )*
1003 $( 971 $(
1004 $(#[$($attr)*])* <<
1005 $fvis unsafe fn $field<E>( 972 $fvis unsafe fn $field<E>(
1006 self, 973 self,
1007 slot: *mut $type, 974 slot: *mut $type,
1008 init: impl $crate::init:: 975 init: impl $crate::init::Init<$type, E>,
1009 ) -> ::core::result::Result<( 976 ) -> ::core::result::Result<(), E> {
1010 unsafe { $crate::init::In 977 unsafe { $crate::init::Init::__init(init, slot) }
1011 } 978 }
1012 )* 979 )*
1013 } 980 }
1014 }; <<
1015 } <<
1016 <<
1017 /// The internal init macro. Do not call manu <<
1018 /// <<
1019 /// This is called by the `{try_}{pin_}init!` <<
1020 /// <<
1021 /// This macro has multiple internal call con <<
1022 /// - nothing: this is the base case and call <<
1023 /// - `with_update_parsed`: when the `..Zeroa <<
1024 /// - `init_slot`: recursively creates the co <<
1025 /// - `make_initializer`: recursively create <<
1026 /// field has been initialized exactly once <<
1027 #[doc(hidden)] <<
1028 #[macro_export] <<
1029 macro_rules! __init_internal { <<
1030 ( <<
1031 @this($($this:ident)?), <<
1032 @typ($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 }; 981 };
1400 } 982 }
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