compio_fs/
file.rs

1use std::{future::Future, io, mem::ManuallyDrop, path::Path};
2
3use compio_buf::{BufResult, IntoInner, IoBuf, IoBufMut};
4#[cfg(unix)]
5use compio_driver::op::FileStat;
6use compio_driver::{
7    BufferRef, ResultTakeBuffer, ToSharedFd, impl_raw_fd,
8    op::{BufResultExt, CloseFile, ReadAt, ReadManagedAt, Sync, WriteAt},
9};
10use compio_io::{AsyncReadAt, AsyncReadManagedAt, AsyncWriteAt, util::Splittable};
11use compio_runtime::{Runtime, fd::AsyncFd};
12#[cfg(all(unix, not(solarish)))]
13use {
14    compio_buf::{IoVectoredBuf, IoVectoredBufMut},
15    compio_driver::op::{ReadVectoredAt, WriteVectoredAt},
16};
17
18use crate::{Metadata, OpenOptions, Permissions};
19
20/// A reference to an open file on the filesystem.
21///
22/// An instance of a `File` can be read and/or written depending on what options
23/// it was opened with. The `File` type provides **positional** read and write
24/// operations. The file does not maintain an internal cursor. The caller is
25/// required to specify an offset when issuing an operation.
26///
27///
28/// If you'd like to use methods from [`AsyncRead`](`compio_io::AsyncRead`) or
29/// [`AsyncWrite`](`compio_io::AsyncWrite`) traits, you can wrap `File` with
30/// [`std::io::Cursor`].
31///
32/// # Examples
33/// ```ignore
34/// use compio::fs::File;
35/// use compio::buf::BufResult;
36/// use std::io::Cursor;
37///
38/// let file = File::open("foo.txt").await?;
39/// let cursor = Cursor::new(file);
40///
41/// let int = cursor.read_u32().await?;
42/// let float = cursor.read_f32().await?;
43///
44/// let mut string = String::new();
45/// let BufResult(result, string) = cursor.read_to_string(string).await;
46///
47/// let mut buf = vec![0; 1024];
48/// let BufResult(result, buf) = cursor.read_exact(buf).await;
49/// ```
50#[derive(Debug, Clone)]
51pub struct File {
52    pub(crate) inner: AsyncFd<std::fs::File>,
53}
54
55impl File {
56    pub(crate) fn from_std(file: std::fs::File) -> io::Result<Self> {
57        Ok(Self {
58            inner: AsyncFd::new(file)?,
59        })
60    }
61
62    /// Attempts to open a file in read-only mode.
63    ///
64    /// See the [`OpenOptions::open`] method for more details.
65    pub async fn open(path: impl AsRef<Path>) -> io::Result<Self> {
66        OpenOptions::new().read(true).open(path).await
67    }
68
69    /// Opens a file in write-only mode.
70    ///
71    /// This function will create a file if it does not exist,
72    /// and will truncate it if it does.
73    ///
74    /// See the [`OpenOptions::open`] function for more details.
75    pub async fn create(path: impl AsRef<Path>) -> io::Result<Self> {
76        OpenOptions::new()
77            .create(true)
78            .write(true)
79            .truncate(true)
80            .open(path)
81            .await
82    }
83
84    /// Close the file. If the returned future is dropped before polling, the
85    /// file won't be closed.
86    ///
87    /// As [`File`] is clonable, users can call `close` on a clone, but the
88    /// future will never complete until all clones are dropped. Some
89    /// operations may keep a strong reference to the file, so the future
90    /// may never complete if there are pending operations.
91    ///
92    /// It's OK to drop the [`File`] directly without calling `close`, but the
93    /// file may not be closed immediately.
94    pub fn close(self) -> impl Future<Output = io::Result<()>> {
95        // Make sure that fd won't be dropped after `close` called.
96        // Users may call this method and drop the future immediately. In that way
97        // `close` should be cancelled.
98        let this = ManuallyDrop::new(self);
99        async move {
100            let fd = ManuallyDrop::into_inner(this)
101                .inner
102                .into_inner()
103                .take()
104                .await;
105            if let Some(fd) = fd {
106                let op = CloseFile::new(fd.into());
107                compio_runtime::submit(op).await.0?;
108            }
109            Ok(())
110        }
111    }
112
113    /// Queries metadata about the underlying file.
114    #[cfg(windows)]
115    pub async fn metadata(&self) -> io::Result<Metadata> {
116        crate::spawn_blocking_with(self.to_shared_fd(), |file| {
117            file.metadata().map(Metadata::from_std)
118        })
119        .await
120    }
121
122    #[cfg(windows)]
123    /// Truncates or extends the underlying file, updating the size of this file
124    /// to become `size`.
125    pub async fn set_len(&self, size: u64) -> io::Result<()> {
126        crate::spawn_blocking_with(self.to_shared_fd(), move |file| file.set_len(size)).await
127    }
128
129    #[cfg(unix)]
130    /// Truncates or extends the underlying file, updating the size of this file
131    /// to become `size`.
132    ///
133    /// NOTE: On Linux kernel <= 6.9 or when io uring is disabled, the operation
134    /// will be offloaded to the separate blocking thread
135    pub async fn set_len(&self, size: u64) -> io::Result<()> {
136        use compio_driver::op::TruncateFile;
137
138        let op = TruncateFile::new(self.to_shared_fd(), size);
139        compio_runtime::submit(op).await.0.map(|_| ())
140    }
141
142    /// Queries metadata about the underlying file.
143    #[cfg(unix)]
144    pub async fn metadata(&self) -> io::Result<Metadata> {
145        let op = FileStat::new(self.to_shared_fd());
146        let BufResult(res, op) = compio_runtime::submit(op).await;
147        res.map(|_| Metadata::from_stat(op.into_inner()))
148    }
149
150    /// Changes the permissions on the underlying file.
151    #[cfg(windows)]
152    pub async fn set_permissions(&self, perm: Permissions) -> io::Result<()> {
153        crate::spawn_blocking_with(self.to_shared_fd(), move |file| {
154            if let Some(p) = perm.0.original {
155                file.set_permissions(p)
156            } else {
157                let mut p = file.metadata()?.permissions();
158                p.set_readonly(perm.readonly());
159                file.set_permissions(p)
160            }
161        })
162        .await
163    }
164
165    /// Changes the permissions on the underlying file.
166    #[cfg(unix)]
167    pub async fn set_permissions(&self, perm: Permissions) -> io::Result<()> {
168        crate::spawn_blocking_with(self.to_shared_fd(), |file| file.set_permissions(perm.0)).await
169    }
170
171    async fn sync_impl(&self, datasync: bool) -> io::Result<()> {
172        let op = Sync::new(self.to_shared_fd(), datasync);
173        compio_runtime::submit(op).await.0?;
174        Ok(())
175    }
176
177    /// Attempts to sync all OS-internal metadata to disk.
178    ///
179    /// This function will attempt to ensure that all in-memory data reaches the
180    /// filesystem before returning.
181    pub async fn sync_all(&self) -> io::Result<()> {
182        self.sync_impl(false).await
183    }
184
185    /// This function is similar to [`sync_all`], except that it might not
186    /// synchronize file metadata to the filesystem.
187    ///
188    /// This is intended for use cases that must synchronize content, but don't
189    /// need the metadata on disk. The goal of this method is to reduce disk
190    /// operations.
191    ///
192    /// Note that some platforms may simply implement this in terms of
193    /// [`sync_all`].
194    ///
195    /// [`sync_all`]: File::sync_all
196    pub async fn sync_data(&self) -> io::Result<()> {
197        self.sync_impl(true).await
198    }
199}
200
201impl AsyncReadAt for File {
202    async fn read_at<T: IoBufMut>(&self, buffer: T, pos: u64) -> BufResult<usize, T> {
203        let fd = self.inner.to_shared_fd();
204        let op = ReadAt::new(fd, pos, buffer);
205        let res = compio_runtime::submit(op).await.into_inner();
206        unsafe { res.map_advanced() }
207    }
208
209    #[cfg(all(unix, not(solarish)))]
210    async fn read_vectored_at<T: IoVectoredBufMut>(
211        &self,
212        buffer: T,
213        pos: u64,
214    ) -> BufResult<usize, T> {
215        use compio_driver::op::VecBufResultExt;
216
217        let fd = self.inner.to_shared_fd();
218        let op = ReadVectoredAt::new(fd, pos, buffer);
219        let res = compio_runtime::submit(op).await.into_inner();
220        unsafe { res.map_vec_advanced() }
221    }
222}
223
224impl AsyncReadManagedAt for File {
225    type Buffer = BufferRef;
226
227    async fn read_managed_at(&self, len: usize, pos: u64) -> io::Result<Option<Self::Buffer>> {
228        let fd = self.inner.to_shared_fd();
229        let res = Runtime::with_current(|rt| {
230            let buffer_pool = rt.buffer_pool()?;
231            let op = ReadManagedAt::new(fd, pos, &buffer_pool, len)?;
232            io::Result::Ok(rt.submit(op))
233        })?
234        .await;
235        unsafe { res.take_buffer() }
236    }
237}
238
239impl AsyncWriteAt for File {
240    #[inline]
241    async fn write_at<T: IoBuf>(&mut self, buf: T, pos: u64) -> BufResult<usize, T> {
242        (&*self).write_at(buf, pos).await
243    }
244
245    #[cfg(all(unix, not(solarish)))]
246    #[inline]
247    async fn write_vectored_at<T: IoVectoredBuf>(
248        &mut self,
249        buf: T,
250        pos: u64,
251    ) -> BufResult<usize, T> {
252        (&*self).write_vectored_at(buf, pos).await
253    }
254}
255
256impl AsyncWriteAt for &File {
257    async fn write_at<T: IoBuf>(&mut self, buffer: T, pos: u64) -> BufResult<usize, T> {
258        let fd = self.inner.to_shared_fd();
259        let op = WriteAt::new(fd, pos, buffer);
260        compio_runtime::submit(op).await.into_inner()
261    }
262
263    #[cfg(all(unix, not(solarish)))]
264    async fn write_vectored_at<T: IoVectoredBuf>(
265        &mut self,
266        buffer: T,
267        pos: u64,
268    ) -> BufResult<usize, T> {
269        let fd = self.inner.to_shared_fd();
270        let op = WriteVectoredAt::new(fd, pos, buffer);
271        compio_runtime::submit(op).await.into_inner()
272    }
273}
274
275impl Splittable for File {
276    type ReadHalf = File;
277    type WriteHalf = File;
278
279    fn split(self) -> (Self::ReadHalf, Self::WriteHalf) {
280        (self.clone(), self)
281    }
282}
283
284impl Splittable for &File {
285    type ReadHalf = File;
286    type WriteHalf = File;
287
288    fn split(self) -> (Self::ReadHalf, Self::WriteHalf) {
289        (self.clone(), self.clone())
290    }
291}
292
293impl Splittable for &mut File {
294    type ReadHalf = File;
295    type WriteHalf = File;
296
297    fn split(self) -> (Self::ReadHalf, Self::WriteHalf) {
298        (self.clone(), self.clone())
299    }
300}
301
302impl_raw_fd!(File, std::fs::File, inner, file);
compio_fs/file.rs

compio_fs/
file.rs
