use crate::fs::asyncify;
use std::collections::VecDeque;
use std::ffi::OsString;
use std::fs::{FileType, Metadata};
use std::future::Future;
use std::io;
use std::path::{Path, PathBuf};
use std::pin::Pin;
use std::sync::Arc;
use std::task::Context;
use std::task::Poll;
#[cfg(test)]
use super::mocks::spawn_blocking;
#[cfg(test)]
use super::mocks::JoinHandle;
#[cfg(not(test))]
use crate::blocking::spawn_blocking;
#[cfg(not(test))]
use crate::blocking::JoinHandle;
const CHUNK_SIZE: usize = 32;
/// Returns a stream over the entries within a directory.
///
/// This is an async version of [`std::fs::read_dir`].
///
/// This operation is implemented by running the equivalent blocking
/// operation on a separate thread pool using [`spawn_blocking`].
///
/// [`spawn_blocking`]: crate::task::spawn_blocking
pub async fn read_dir(path: impl AsRef<Path>) -> io::Result<ReadDir> {
let path = path.as_ref().to_owned();
asyncify(|| -> io::Result<ReadDir> {
let mut std = std::fs::read_dir(path)?;
let mut buf = VecDeque::with_capacity(CHUNK_SIZE);
let remain = ReadDir::next_chunk(&mut buf, &mut std);
Ok(ReadDir(State::Idle(Some((buf, std, remain)))))
})
.await
}
/// Reads the entries in a directory.
///
/// This struct is returned from the [`read_dir`] function of this module and
/// will yield instances of [`DirEntry`]. Through a [`DirEntry`] information
/// like the entry's path and possibly other metadata can be learned.
///
/// A `ReadDir` can be turned into a `Stream` with [`ReadDirStream`].
///
/// [`ReadDirStream`]: https://docs.rs/tokio-stream/0.1/tokio_stream/wrappers/struct.ReadDirStream.html
///
/// # Errors
///
/// This stream will return an [`Err`] if there's some sort of intermittent
/// IO error during iteration.
///
/// [`read_dir`]: read_dir
/// [`DirEntry`]: DirEntry
/// [`Err`]: std::result::Result::Err
#[derive(Debug)]
#[must_use = "streams do nothing unless polled"]
pub struct ReadDir(State);
#[derive(Debug)]
enum State {
Idle(Option<(VecDeque<io::Result<DirEntry>>, std::fs::ReadDir, bool)>),
Pending(JoinHandle<(VecDeque<io::Result<DirEntry>>, std::fs::ReadDir, bool)>),
}
impl ReadDir {
/// Returns the next entry in the directory stream.
///
/// # Cancel safety
///
/// This method is cancellation safe.
pub async fn next_entry(&mut self) -> io::Result<Option<DirEntry>> {
use crate::future::poll_fn;
poll_fn(|cx| self.poll_next_entry(cx)).await
}
/// Polls for the next directory entry in the stream.
///
/// This method returns:
///
/// * `Poll::Pending` if the next directory entry is not yet available.
/// * `Poll::Ready(Ok(Some(entry)))` if the next directory entry is available.
/// * `Poll::Ready(Ok(None))` if there are no more directory entries in this
/// stream.
/// * `Poll::Ready(Err(err))` if an IO error occurred while reading the next
/// directory entry.
///
/// When the method returns `Poll::Pending`, the `Waker` in the provided
/// `Context` is scheduled to receive a wakeup when the next directory entry
/// becomes available on the underlying IO resource.
///
/// Note that on multiple calls to `poll_next_entry`, only the `Waker` from
/// the `Context` passed to the most recent call is scheduled to receive a
/// wakeup.
pub fn poll_next_entry(&mut self, cx: &mut Context<'_>) -> Poll<io::Result<Option<DirEntry>>> {
loop {
match self.0 {
State::Idle(ref mut data) => {
let (buf, _, ref remain) = data.as_mut().unwrap();
if let Some(ent) = buf.pop_front() {
return Poll::Ready(ent.map(Some));
} else if !remain {
return Poll::Ready(Ok(None));
}
let (mut buf, mut std, _) = data.take().unwrap();
self.0 = State::Pending(spawn_blocking(move || {
let remain = ReadDir::next_chunk(&mut buf, &mut std);
(buf, std, remain)
}));
}
State::Pending(ref mut rx) => {
self.0 = State::Idle(Some(ready!(Pin::new(rx).poll(cx))?));
}
}
}
}
fn next_chunk(buf: &mut VecDeque<io::Result<DirEntry>>, std: &mut std::fs::ReadDir) -> bool {
for _ in 0..CHUNK_SIZE {
let ret = match std.next() {
Some(ret) => ret,
None => return false,
};
let success = ret.is_ok();
buf.push_back(ret.map(|std| DirEntry {
#[cfg(not(any(
target_os = "solaris",
target_os = "illumos",
target_os = "haiku",
target_os = "vxworks",
target_os = "aix",
target_os = "nto",
target_os = "vita",
)))]
file_type: std.file_type().ok(),
std: Arc::new(std),
}));
if !success {
break;
}
}
true
}
}
feature! {
#![unix]
use std::os::unix::fs::DirEntryExt;
impl DirEntry {
/// Returns the underlying `d_ino` field in the contained `dirent`
/// structure.
///
/// # Examples
///
/// ```
/// use tokio::fs;
///
/// # #[tokio::main]
/// # async fn main() -> std::io::Result<()> {
/// let mut entries = fs::read_dir(".").await?;
/// while let Some(entry) = entries.next_entry().await? {
/// // Here, `entry` is a `DirEntry`.
/// println!("{:?}: {}", entry.file_name(), entry.ino());
/// }
/// # Ok(())
/// # }
/// ```
pub fn ino(&self) -> u64 {
self.as_inner().ino()
}
}
}
/// Entries returned by the [`ReadDir`] stream.
///
/// [`ReadDir`]: struct@ReadDir
///
/// This is a specialized version of [`std::fs::DirEntry`] for usage from the
/// Tokio runtime.
///
/// An instance of `DirEntry` represents an entry inside of a directory on the
/// filesystem. Each entry can be inspected via methods to learn about the full
/// path or possibly other metadata through per-platform extension traits.
#[derive(Debug)]
pub struct DirEntry {
#[cfg(not(any(
target_os = "solaris",
target_os = "illumos",
target_os = "haiku",
target_os = "vxworks",
target_os = "aix",
target_os = "nto",
target_os = "vita",
)))]
file_type: Option<FileType>,
std: Arc<std::fs::DirEntry>,
}
impl DirEntry {
/// Returns the full path to the file that this entry represents.
///
/// The full path is created by joining the original path to `read_dir`
/// with the filename of this entry.
///
/// # Examples
///
/// ```no_run
/// use tokio::fs;
///
/// # async fn dox() -> std::io::Result<()> {
/// let mut entries = fs::read_dir(".").await?;
///
/// while let Some(entry) = entries.next_entry().await? {
/// println!("{:?}", entry.path());
/// }
/// # Ok(())
/// # }
/// ```
///
/// This prints output like:
///
/// ```text
/// "./whatever.txt"
/// "./foo.html"
/// "./hello_world.rs"
/// ```
///
/// The exact text, of course, depends on what files you have in `.`.
pub fn path(&self) -> PathBuf {
self.std.path()
}
/// Returns the bare file name of this directory entry without any other
/// leading path component.
///
/// # Examples
///
/// ```
/// use tokio::fs;
///
/// # async fn dox() -> std::io::Result<()> {
/// let mut entries = fs::read_dir(".").await?;
///
/// while let Some(entry) = entries.next_entry().await? {
/// println!("{:?}", entry.file_name());
/// }
/// # Ok(())
/// # }
/// ```
pub fn file_name(&self) -> OsString {
self.std.file_name()
}
/// Returns the metadata for the file that this entry points at.
///
/// This function will not traverse symlinks if this entry points at a
/// symlink.
///
/// # Platform-specific behavior
///
/// On Windows this function is cheap to call (no extra system calls
/// needed), but on Unix platforms this function is the equivalent of
/// calling `symlink_metadata` on the path.
///
/// # Examples
///
/// ```
/// use tokio::fs;
///
/// # async fn dox() -> std::io::Result<()> {
/// let mut entries = fs::read_dir(".").await?;
///
/// while let Some(entry) = entries.next_entry().await? {
/// if let Ok(metadata) = entry.metadata().await {
/// // Now let's show our entry's permissions!
/// println!("{:?}: {:?}", entry.path(), metadata.permissions());
/// } else {
/// println!("Couldn't get file type for {:?}", entry.path());
/// }
/// }
/// # Ok(())
/// # }
/// ```
pub async fn metadata(&self) -> io::Result<Metadata> {
let std = self.std.clone();
asyncify(move || std.metadata()).await
}
/// Returns the file type for the file that this entry points at.
///
/// This function will not traverse symlinks if this entry points at a
/// symlink.
///
/// # Platform-specific behavior
///
/// On Windows and most Unix platforms this function is free (no extra
/// system calls needed), but some Unix platforms may require the equivalent
/// call to `symlink_metadata` to learn about the target file type.
///
/// # Examples
///
/// ```
/// use tokio::fs;
///
/// # async fn dox() -> std::io::Result<()> {
/// let mut entries = fs::read_dir(".").await?;
///
/// while let Some(entry) = entries.next_entry().await? {
/// if let Ok(file_type) = entry.file_type().await {
/// // Now let's show our entry's file type!
/// println!("{:?}: {:?}", entry.path(), file_type);
/// } else {
/// println!("Couldn't get file type for {:?}", entry.path());
/// }
/// }
/// # Ok(())
/// # }
/// ```
pub async fn file_type(&self) -> io::Result<FileType> {
#[cfg(not(any(
target_os = "solaris",
target_os = "illumos",
target_os = "haiku",
target_os = "vxworks",
target_os = "aix",
target_os = "nto",
target_os = "vita",
)))]
if let Some(file_type) = self.file_type {
return Ok(file_type);
}
let std = self.std.clone();
asyncify(move || std.file_type()).await
}
/// Returns a reference to the underlying `std::fs::DirEntry`.
#[cfg(unix)]
pub(super) fn as_inner(&self) -> &std::fs::DirEntry {
&self.std
}
}