Line data Source code
1 : use std::mem::MaybeUninit;
2 : use std::ops::{Deref, DerefMut};
3 :
4 : use super::alignment::{Alignment, ConstAlign};
5 : use super::buffer::AlignedBuffer;
6 : use super::raw::RawAlignedBuffer;
7 :
8 : /// A mutable aligned buffer type.
9 : #[derive(Debug)]
10 : pub struct AlignedBufferMut<A: Alignment> {
11 : raw: RawAlignedBuffer<A>,
12 : }
13 :
14 : impl<const A: usize> AlignedBufferMut<ConstAlign<A>> {
15 : /// Constructs a new, empty `IoBufferMut` with at least the specified capacity and alignment.
16 : ///
17 : /// The buffer will be able to hold at most `capacity` elements and will never resize.
18 : ///
19 : ///
20 : /// # Panics
21 : ///
22 : /// Panics if the new capacity exceeds `isize::MAX` _bytes_, or if the following alignment requirement is not met:
23 : /// * `align` must not be zero,
24 : ///
25 : /// * `align` must be a power of two,
26 : ///
27 : /// * `capacity`, when rounded up to the nearest multiple of `align`,
28 : /// must not overflow isize (i.e., the rounded value must be
29 : /// less than or equal to `isize::MAX`).
30 1440478 : pub fn with_capacity(capacity: usize) -> Self {
31 1440478 : AlignedBufferMut {
32 1440478 : raw: RawAlignedBuffer::with_capacity(capacity),
33 1440478 : }
34 1440478 : }
35 :
36 : /// Constructs a new `IoBufferMut` with at least the specified capacity and alignment, filled with zeros.
37 612 : pub fn with_capacity_zeroed(capacity: usize) -> Self {
38 : use bytes::BufMut;
39 612 : let mut buf = Self::with_capacity(capacity);
40 612 : buf.put_bytes(0, capacity);
41 612 : // SAFETY: `put_bytes` filled the entire buffer.
42 612 : unsafe { buf.set_len(capacity) };
43 612 : buf
44 612 : }
45 : }
46 :
47 : impl<A: Alignment> AlignedBufferMut<A> {
48 : /// Constructs a mutable aligned buffer from raw.
49 13246 : pub(super) fn from_raw(raw: RawAlignedBuffer<A>) -> Self {
50 13246 : AlignedBufferMut { raw }
51 13246 : }
52 :
53 : /// Returns the total number of bytes the buffer can hold.
54 : #[inline]
55 53703381 : pub fn capacity(&self) -> usize {
56 53703381 : self.raw.capacity()
57 53703381 : }
58 :
59 : /// Returns the alignment of the buffer.
60 : #[inline]
61 44 : pub fn align(&self) -> usize {
62 44 : self.raw.align()
63 44 : }
64 :
65 : /// Returns the number of bytes in the buffer, also referred to as its 'length'.
66 : #[inline]
67 85424215 : pub fn len(&self) -> usize {
68 85424215 : self.raw.len()
69 85424215 : }
70 :
71 : /// Force the length of the buffer to `new_len`.
72 : #[inline]
73 11062586 : unsafe fn set_len(&mut self, new_len: usize) {
74 11062586 : // SAFETY: the caller is unsafe
75 11062586 : unsafe { self.raw.set_len(new_len) }
76 11062586 : }
77 :
78 : #[inline]
79 6570281 : fn as_ptr(&self) -> *const u8 {
80 6570281 : self.raw.as_ptr()
81 6570281 : }
82 :
83 : #[inline]
84 12941083 : fn as_mut_ptr(&mut self) -> *mut u8 {
85 12941083 : self.raw.as_mut_ptr()
86 12941083 : }
87 :
88 : /// Extracts a slice containing the entire buffer.
89 : ///
90 : /// Equivalent to `&s[..]`.
91 : #[inline]
92 8367887 : fn as_slice(&self) -> &[u8] {
93 8367887 : self.raw.as_slice()
94 8367887 : }
95 :
96 : /// Extracts a mutable slice of the entire buffer.
97 : ///
98 : /// Equivalent to `&mut s[..]`.
99 0 : fn as_mut_slice(&mut self) -> &mut [u8] {
100 0 : self.raw.as_mut_slice()
101 0 : }
102 :
103 : /// Drops the all the contents of the buffer, setting its length to `0`.
104 : #[inline]
105 13298 : pub fn clear(&mut self) {
106 13298 : self.raw.clear()
107 13298 : }
108 :
109 : /// Reserves capacity for at least `additional` more bytes to be inserted
110 : /// in the given `IoBufferMut`. The collection may reserve more space to
111 : /// speculatively avoid frequent reallocations. After calling `reserve`,
112 : /// capacity will be greater than or equal to `self.len() + additional`.
113 : /// Does nothing if capacity is already sufficient.
114 : ///
115 : /// # Panics
116 : ///
117 : /// Panics if the new capacity exceeds `isize::MAX` _bytes_.
118 9623144 : pub fn reserve(&mut self, additional: usize) {
119 9623144 : self.raw.reserve(additional);
120 9623144 : }
121 :
122 : /// Shortens the buffer, keeping the first len bytes.
123 20 : pub fn truncate(&mut self, len: usize) {
124 20 : self.raw.truncate(len);
125 20 : }
126 :
127 : /// Consumes and leaks the `IoBufferMut`, returning a mutable reference to the contents, &'a mut [u8].
128 188 : pub fn leak<'a>(self) -> &'a mut [u8] {
129 188 : self.raw.leak()
130 188 : }
131 :
132 17826 : pub fn freeze(self) -> AlignedBuffer<A> {
133 17826 : let len = self.len();
134 17826 : AlignedBuffer::from_raw(self.raw, 0..len)
135 17826 : }
136 :
137 : /// Clones and appends all elements in a slice to the buffer. Reserves additional capacity as needed.
138 : #[inline]
139 9623100 : pub fn extend_from_slice(&mut self, extend: &[u8]) {
140 9623100 : let cnt = extend.len();
141 9623100 : self.reserve(cnt);
142 9623100 :
143 9623100 : // SAFETY: we already reserved additional `cnt` bytes, safe to perform memcpy.
144 9623100 : unsafe {
145 9623100 : let dst = self.spare_capacity_mut();
146 9623100 : // Reserved above
147 9623100 : debug_assert!(dst.len() >= cnt);
148 :
149 9623100 : core::ptr::copy_nonoverlapping(extend.as_ptr(), dst.as_mut_ptr().cast(), cnt);
150 9623100 : }
151 9623100 : // SAFETY: We do have at least `cnt` bytes remaining before advance.
152 9623100 : unsafe {
153 9623100 : bytes::BufMut::advance_mut(self, cnt);
154 9623100 : }
155 9623100 : }
156 :
157 : /// Returns the remaining spare capacity of the vector as a slice of `MaybeUninit<u8>`.
158 : #[inline]
159 9623100 : fn spare_capacity_mut(&mut self) -> &mut [MaybeUninit<u8>] {
160 9623100 : // SAFETY: we guarantees that the `Self::capacity()` bytes from
161 9623100 : // `Self::as_mut_ptr()` are allocated.
162 9623100 : unsafe {
163 9623100 : let ptr = self.as_mut_ptr().add(self.len());
164 9623100 : let len = self.capacity() - self.len();
165 9623100 :
166 9623100 : core::slice::from_raw_parts_mut(ptr.cast(), len)
167 9623100 : }
168 9623100 : }
169 : }
170 :
171 : impl<A: Alignment> Deref for AlignedBufferMut<A> {
172 : type Target = [u8];
173 :
174 8366479 : fn deref(&self) -> &Self::Target {
175 8366479 : self.as_slice()
176 8366479 : }
177 : }
178 :
179 : impl<A: Alignment> DerefMut for AlignedBufferMut<A> {
180 0 : fn deref_mut(&mut self) -> &mut Self::Target {
181 0 : self.as_mut_slice()
182 0 : }
183 : }
184 :
185 : impl<A: Alignment> AsRef<[u8]> for AlignedBufferMut<A> {
186 0 : fn as_ref(&self) -> &[u8] {
187 0 : self.as_slice()
188 0 : }
189 : }
190 :
191 : impl<A: Alignment> AsMut<[u8]> for AlignedBufferMut<A> {
192 0 : fn as_mut(&mut self) -> &mut [u8] {
193 0 : self.as_mut_slice()
194 0 : }
195 : }
196 :
197 : impl<A: Alignment> PartialEq<[u8]> for AlignedBufferMut<A> {
198 1408 : fn eq(&self, other: &[u8]) -> bool {
199 1408 : self.as_slice().eq(other)
200 1408 : }
201 : }
202 :
203 : /// SAFETY: When advancing the internal cursor, the caller needs to make sure the bytes advcanced past have been initialized.
204 : unsafe impl<A: Alignment> bytes::BufMut for AlignedBufferMut<A> {
205 : #[inline]
206 9624436 : fn remaining_mut(&self) -> usize {
207 9624436 : // Although a `Vec` can have at most isize::MAX bytes, we never want to grow `IoBufferMut`.
208 9624436 : // Thus, it can have at most `self.capacity` bytes.
209 9624436 : self.capacity() - self.len()
210 9624436 : }
211 :
212 : // SAFETY: Caller needs to make sure the bytes being advanced past have been initialized.
213 : #[inline]
214 9623764 : unsafe fn advance_mut(&mut self, cnt: usize) {
215 9623764 : let len = self.len();
216 9623764 : let remaining = self.remaining_mut();
217 9623764 :
218 9623764 : if remaining < cnt {
219 0 : panic_advance(cnt, remaining);
220 9623764 : }
221 9623764 :
222 9623764 : // SAFETY: Addition will not overflow since the sum is at most the capacity.
223 9623764 : unsafe {
224 9623764 : self.set_len(len + cnt);
225 9623764 : }
226 9623764 : }
227 :
228 : #[inline]
229 664 : fn chunk_mut(&mut self) -> &mut bytes::buf::UninitSlice {
230 664 : let cap = self.capacity();
231 664 : let len = self.len();
232 664 :
233 664 : // SAFETY: Since `self.ptr` is valid for `cap` bytes, `self.ptr.add(len)` must be
234 664 : // valid for `cap - len` bytes. The subtraction will not underflow since
235 664 : // `len <= cap`.
236 664 : unsafe {
237 664 : bytes::buf::UninitSlice::from_raw_parts_mut(self.as_mut_ptr().add(len), cap - len)
238 664 : }
239 664 : }
240 : }
241 :
242 : /// Panic with a nice error message.
243 : #[cold]
244 0 : fn panic_advance(idx: usize, len: usize) -> ! {
245 0 : panic!(
246 0 : "advance out of bounds: the len is {} but advancing by {}",
247 0 : len, idx
248 0 : );
249 : }
250 :
251 : /// Safety: [`AlignedBufferMut`] has exclusive ownership of the io buffer,
252 : /// and the underlying pointer remains stable while io-uring is owning the buffer.
253 : /// The tokio-epoll-uring crate itself will not resize the buffer and will respect
254 : /// [`tokio_epoll_uring::IoBuf::bytes_total`].
255 : unsafe impl<A: Alignment> tokio_epoll_uring::IoBuf for AlignedBufferMut<A> {
256 6570245 : fn stable_ptr(&self) -> *const u8 {
257 6570245 : self.as_ptr()
258 6570245 : }
259 :
260 14136231 : fn bytes_init(&self) -> usize {
261 14136231 : self.len()
262 14136231 : }
263 :
264 5129584 : fn bytes_total(&self) -> usize {
265 5129584 : self.capacity()
266 5129584 : }
267 : }
268 :
269 : // SAFETY: See above.
270 : unsafe impl<A: Alignment> tokio_epoll_uring::IoBufMut for AlignedBufferMut<A> {
271 3317319 : fn stable_mut_ptr(&mut self) -> *mut u8 {
272 3317319 : self.as_mut_ptr()
273 3317319 : }
274 :
275 1884470 : unsafe fn set_init(&mut self, init_len: usize) {
276 1884470 : if self.len() < init_len {
277 : // SAFETY: caller function is unsafe
278 1438210 : unsafe {
279 1438210 : self.set_len(init_len);
280 1438210 : }
281 446260 : }
282 1884470 : }
283 : }
284 :
285 : #[cfg(test)]
286 : mod tests {
287 :
288 : use super::*;
289 :
290 : const ALIGN: usize = 4 * 1024;
291 : type TestIoBufferMut = AlignedBufferMut<ConstAlign<ALIGN>>;
292 :
293 : #[test]
294 4 : fn test_with_capacity() {
295 4 : let v = TestIoBufferMut::with_capacity(ALIGN * 4);
296 4 : assert_eq!(v.len(), 0);
297 4 : assert_eq!(v.capacity(), ALIGN * 4);
298 4 : assert_eq!(v.align(), ALIGN);
299 4 : assert_eq!(v.as_ptr().align_offset(ALIGN), 0);
300 :
301 4 : let v = TestIoBufferMut::with_capacity(ALIGN / 2);
302 4 : assert_eq!(v.len(), 0);
303 4 : assert_eq!(v.capacity(), ALIGN / 2);
304 4 : assert_eq!(v.align(), ALIGN);
305 4 : assert_eq!(v.as_ptr().align_offset(ALIGN), 0);
306 4 : }
307 :
308 : #[test]
309 4 : fn test_with_capacity_zeroed() {
310 4 : let v = TestIoBufferMut::with_capacity_zeroed(ALIGN);
311 4 : assert_eq!(v.len(), ALIGN);
312 4 : assert_eq!(v.capacity(), ALIGN);
313 4 : assert_eq!(v.align(), ALIGN);
314 4 : assert_eq!(v.as_ptr().align_offset(ALIGN), 0);
315 4 : assert_eq!(&v[..], &[0; ALIGN])
316 4 : }
317 :
318 : #[test]
319 4 : fn test_reserve() {
320 : use bytes::BufMut;
321 4 : let mut v = TestIoBufferMut::with_capacity(ALIGN);
322 4 : let capacity = v.capacity();
323 4 : v.reserve(capacity);
324 4 : assert_eq!(v.capacity(), capacity);
325 4 : let data = [b'a'; ALIGN];
326 4 : v.put(&data[..]);
327 4 : v.reserve(capacity);
328 4 : assert!(v.capacity() >= capacity * 2);
329 4 : assert_eq!(&v[..], &data[..]);
330 4 : let capacity = v.capacity();
331 4 : v.clear();
332 4 : v.reserve(capacity);
333 4 : assert_eq!(capacity, v.capacity());
334 4 : }
335 :
336 : #[test]
337 4 : fn test_bytes_put() {
338 : use bytes::BufMut;
339 4 : let mut v = TestIoBufferMut::with_capacity(ALIGN * 4);
340 4 : let x = [b'a'; ALIGN];
341 :
342 12 : for _ in 0..2 {
343 40 : for _ in 0..4 {
344 32 : v.put(&x[..]);
345 32 : }
346 8 : assert_eq!(v.len(), ALIGN * 4);
347 8 : assert_eq!(v.capacity(), ALIGN * 4);
348 8 : assert_eq!(v.align(), ALIGN);
349 8 : assert_eq!(v.as_ptr().align_offset(ALIGN), 0);
350 8 : v.clear()
351 : }
352 4 : assert_eq!(v.len(), 0);
353 4 : assert_eq!(v.capacity(), ALIGN * 4);
354 4 : assert_eq!(v.align(), ALIGN);
355 4 : assert_eq!(v.as_ptr().align_offset(ALIGN), 0);
356 4 : }
357 :
358 : #[test]
359 : #[should_panic]
360 4 : fn test_bytes_put_panic() {
361 : use bytes::BufMut;
362 : const ALIGN: usize = 4 * 1024;
363 4 : let mut v = TestIoBufferMut::with_capacity(ALIGN * 4);
364 4 : let x = [b'a'; ALIGN];
365 24 : for _ in 0..5 {
366 20 : v.put_slice(&x[..]);
367 20 : }
368 4 : }
369 :
370 : #[test]
371 4 : fn test_io_buf_put_slice() {
372 : use tokio_epoll_uring::BoundedBufMut;
373 : const ALIGN: usize = 4 * 1024;
374 4 : let mut v = TestIoBufferMut::with_capacity(ALIGN);
375 4 : let x = [b'a'; ALIGN];
376 :
377 12 : for _ in 0..2 {
378 8 : v.put_slice(&x[..]);
379 8 : assert_eq!(v.len(), ALIGN);
380 8 : assert_eq!(v.capacity(), ALIGN);
381 8 : assert_eq!(v.align(), ALIGN);
382 8 : assert_eq!(v.as_ptr().align_offset(ALIGN), 0);
383 8 : v.clear()
384 : }
385 4 : assert_eq!(v.len(), 0);
386 4 : assert_eq!(v.capacity(), ALIGN);
387 4 : assert_eq!(v.align(), ALIGN);
388 4 : assert_eq!(v.as_ptr().align_offset(ALIGN), 0);
389 4 : }
390 : }
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