Struct async_std::pin::Pin

#[lang = "pin"]
#[repr(transparent)]
pub struct Pin<P> { /* fields omitted */ }

This is supported on unstable only.

A pinned pointer.

This is a wrapper around a kind of pointer which makes that pointer "pin" its value in place, preventing the value referenced by that pointer from being moved unless it implements Unpin.

See the pin module documentation for an explanation of pinning.

Methods

impl<P> Pin<P> where
    P: Deref,
    <P as Deref>::Target: Unpin, 

Important traits for Pin<P>

impl<P> Future for Pin<P> where
    P: Unpin + DerefMut,
    <P as Deref>::Target: Future,  type Output = <<P as Deref>::Target as Future>::Output;

pub fn new(pointer: P) -> Pin<P>

This is supported on unstable only.

Construct a new Pin<P> around a pointer to some data of a type that implements Unpin.

Unlike Pin::new_unchecked, this method is safe because the pointer P dereferences to an Unpin type, which cancels the pinning guarantees.

pub fn into_inner(pin: Pin<P>) -> P

This is supported on unstable only.

Unwraps this Pin<P> returning the underlying pointer.

This requires that the data inside this Pin is Unpin so that we can ignore the pinning invariants when unwrapping it.

impl<P> Pin<P> where
    P: Deref, 

Important traits for Pin<P>

impl<P> Future for Pin<P> where
    P: Unpin + DerefMut,
    <P as Deref>::Target: Future,  type Output = <<P as Deref>::Target as Future>::Output;

pub unsafe fn new_unchecked(pointer: P) -> Pin<P>

This is supported on unstable only.

Construct a new Pin<P> around a reference to some data of a type that may or may not implement Unpin.

If pointer dereferences to an Unpin type, Pin::new should be used instead.

Safety

This constructor is unsafe because we cannot guarantee that the data pointed to by pointer is pinned, meaning that the data will not be moved or its storage invalidated until it gets dropped. If the constructed Pin<P> does not guarantee that the data P points to is pinned, that is a violation of the API contract and may lead to undefined behavior in later (safe) operations.

By using this method, you are making a promise about the P::Deref and P::DerefMut implementations, if they exist. Most importantly, they must not move out of their self arguments: Pin::as_mut and Pin::as_ref will call DerefMut::deref_mut and Deref::deref on the pinned pointer and expect these methods to uphold the pinning invariants. Moreover, by calling this method you promise that the reference P dereferences to will not be moved out of again; in particular, it must not be possible to obtain a &mut P::Target and then move out of that reference (using, for example mem::swap).

For example, calling Pin::new_unchecked on an &'a mut T is unsafe because while you are able to pin it for the given lifetime 'a, you have no control over whether it is kept pinned once 'a ends:

use std::mem;
use std::pin::Pin;

fn move_pinned_ref<T>(mut a: T, mut b: T) {
    unsafe {
        let p: Pin<&mut T> = Pin::new_unchecked(&mut a);
        // This should mean the pointee `a` can never move again.
    }
    mem::swap(&mut a, &mut b);
    // The address of `a` changed to `b`'s stack slot, so `a` got moved even
    // though we have previously pinned it! We have violated the pinning API contract.
}

A value, once pinned, must remain pinned forever (unless its type implements Unpin).

Similarily, calling Pin::new_unchecked on an Rc<T> is unsafe because there could be aliases to the same data that are not subject to the pinning restrictions:

use std::rc::Rc;
use std::pin::Pin;

fn move_pinned_rc<T>(mut x: Rc<T>) {
    let pinned = unsafe { Pin::new_unchecked(x.clone()) };
    {
        let p: Pin<&T> = pinned.as_ref();
        // This should mean the pointee can never move again.
    }
    drop(pinned);
    let content = Rc::get_mut(&mut x).unwrap();
    // Now, if `x` was the only reference, we have a mutable reference to
    // data that we pinned above, which we could use to move it as we have
    // seen in the previous example. We have violated the pinning API contract.
 }

Important traits for Pin<P>

impl<P> Future for Pin<P> where
    P: Unpin + DerefMut,
    <P as Deref>::Target: Future,  type Output = <<P as Deref>::Target as Future>::Output;

pub fn as_ref(&self) -> Pin<&<P as Deref>::Target>

This is supported on unstable only.

Gets a pinned shared reference from this pinned pointer.

This is a generic method to go from &Pin<Pointer<T>> to Pin<&T>. It is safe because, as part of the contract of Pin::new_unchecked, the pointee cannot move after Pin<Pointer<T>> got created. "Malicious" implementations of Pointer::Deref are likewise ruled out by the contract of Pin::new_unchecked.

pub unsafe fn into_inner_unchecked(pin: Pin<P>) -> P

This is supported on unstable only.

Unwraps this Pin<P> returning the underlying pointer.

Safety

This function is unsafe. You must guarantee that you will continue to treat the pointer P as pinned after you call this function, so that the invariants on the Pin type can be upheld. If the code using the resulting P does not continue to maintain the pinning invariants that is a violation of the API contract and may lead to undefined behavior in later (safe) operations.

If the underlying data is Unpin, Pin::into_inner should be used instead.

impl<P> Pin<P> where
    P: DerefMut, 

Important traits for Pin<P>

impl<P> Future for Pin<P> where
    P: Unpin + DerefMut,
    <P as Deref>::Target: Future,  type Output = <<P as Deref>::Target as Future>::Output;

pub fn as_mut(&mut self) -> Pin<&mut <P as Deref>::Target>

This is supported on unstable only.

Gets a pinned mutable reference from this pinned pointer.

This is a generic method to go from &mut Pin<Pointer<T>> to Pin<&mut T>. It is safe because, as part of the contract of Pin::new_unchecked, the pointee cannot move after Pin<Pointer<T>> got created. "Malicious" implementations of Pointer::DerefMut are likewise ruled out by the contract of Pin::new_unchecked.

This method is useful when doing multiple calls to functions that consume the pinned type.

Example

use std::pin::Pin;

impl Type {
    fn method(self: Pin<&mut Self>) {
        // do something
    }

    fn call_method_twice(mut self: Pin<&mut Self>) {
        // `method` consumes `self`, so reborrow the `Pin<&mut Self>` via `as_mut`.
        self.as_mut().method();
        self.as_mut().method();
    }
}

pub fn set(&mut self, value: <P as Deref>::Target) where
    <P as Deref>::Target: Sized, 

This is supported on unstable only.

Assigns a new value to the memory behind the pinned reference.

This overwrites pinned data, but that is okay: its destructor gets run before being overwritten, so no pinning guarantee is violated.

impl<'a, T> Pin<&'a T> where
    T: ?Sized, 

Important traits for Pin<P>

impl<P> Future for Pin<P> where
    P: Unpin + DerefMut,
    <P as Deref>::Target: Future,  type Output = <<P as Deref>::Target as Future>::Output;

pub unsafe fn map_unchecked<U, F>(self, func: F) -> Pin<&'a U> where
    F: FnOnce(&T) -> &U, 

This is supported on unstable only.

Constructs a new pin by mapping the interior value.

For example, if you wanted to get a Pin of a field of something, you could use this to get access to that field in one line of code. However, there are several gotchas with these "pinning projections"; see the pin module documentation for further details on that topic.

Safety

This function is unsafe. You must guarantee that the data you return will not move so long as the argument value does not move (for example, because it is one of the fields of that value), and also that you do not move out of the argument you receive to the interior function.

pub fn get_ref(self) -> &'a T

This is supported on unstable only.

Gets a shared reference out of a pin.

This is safe because it is not possible to move out of a shared reference. It may seem like there is an issue here with interior mutability: in fact, it is possible to move a T out of a &RefCell<T>. However, this is not a problem as long as there does not also exist a Pin<&T> pointing to the same data, and RefCell<T> does not let you create a pinned reference to its contents. See the discussion on "pinning projections" for further details.

Note: Pin also implements Deref to the target, which can be used to access the inner value. However, Deref only provides a reference that lives for as long as the borrow of the Pin, not the lifetime of the Pin itself. This method allows turning the Pin into a reference with the same lifetime as the original Pin.

impl<'a, T> Pin<&'a mut T> where
    T: ?Sized, 

Important traits for Pin<P>

impl<P> Future for Pin<P> where
    P: Unpin + DerefMut,
    <P as Deref>::Target: Future,  type Output = <<P as Deref>::Target as Future>::Output;

pub fn into_ref(self) -> Pin<&'a T>

This is supported on unstable only.

Converts this Pin<&mut T> into a Pin<&T> with the same lifetime.

pub fn get_mut(self) -> &'a mut T where
    T: Unpin, 

This is supported on unstable only.

Gets a mutable reference to the data inside of this Pin.

This requires that the data inside this Pin is Unpin.

Note: Pin also implements DerefMut to the data, which can be used to access the inner value. However, DerefMut only provides a reference that lives for as long as the borrow of the Pin, not the lifetime of the Pin itself. This method allows turning the Pin into a reference with the same lifetime as the original Pin.

pub unsafe fn get_unchecked_mut(self) -> &'a mut T

This is supported on unstable only.

Gets a mutable reference to the data inside of this Pin.

Safety

This function is unsafe. You must guarantee that you will never move the data out of the mutable reference you receive when you call this function, so that the invariants on the Pin type can be upheld.

If the underlying data is Unpin, Pin::get_mut should be used instead.

Important traits for Pin<P>

impl<P> Future for Pin<P> where
    P: Unpin + DerefMut,
    <P as Deref>::Target: Future,  type Output = <<P as Deref>::Target as Future>::Output;

pub unsafe fn map_unchecked_mut<U, F>(self, func: F) -> Pin<&'a mut U> where
    F: FnOnce(&mut T) -> &mut U, 

This is supported on unstable only.

Construct a new pin by mapping the interior value.

For example, if you wanted to get a Pin of a field of something, you could use this to get access to that field in one line of code. However, there are several gotchas with these "pinning projections"; see the pin module documentation for further details on that topic.

Safety

This function is unsafe. You must guarantee that the data you return will not move so long as the argument value does not move (for example, because it is one of the fields of that value), and also that you do not move out of the argument you receive to the interior function.

Trait Implementations

impl<P, Q> PartialEq<Pin<Q>> for Pin<P> where
    P: PartialEq<Q>, 

fn eq(&self, other: &Pin<Q>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Pin<Q>) -> bool

This method tests for !=.

impl<P, U> DispatchFromDyn<Pin<U>> for Pin<P> where
    P: DispatchFromDyn<U>, 

impl<P> Hash for Pin<P> where
    P: Hash, 

fn hash<__H>(&self, state: &mut __H) where
    __H: Hasher, 

Feeds this value into the given [Hasher].

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given [Hasher].

impl<P> Ord for Pin<P> where
    P: Ord, 

fn cmp(&self, other: &Pin<P>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

🔬 This is a nightly-only experimental API. (clamp)

Restrict a value to a certain interval.

impl<P> StructuralEq for Pin<P>

impl<P> Pointer for Pin<P> where
    P: Pointer, 

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl<P> Future for Pin<P> where
    P: Unpin + DerefMut,
    <P as Deref>::Target: Future, 

type Output = <<P as Deref>::Target as Future>::Output

The type of value produced on completion.

fn poll(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context
) -> Poll<<Pin<P> as Future>::Output>

Attempt to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.

impl<P> Display for Pin<P> where
    P: Display, 

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl<P> Deref for Pin<P> where
    P: Deref, 

type Target = <P as Deref>::Target

The resulting type after dereferencing.

fn deref(&self) -> &<P as Deref>::Target

Dereferences the value.

impl<P> Debug for Pin<P> where
    P: Debug, 

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl<P> Clone for Pin<P> where
    P: Clone, 

Important traits for Pin<P>

impl<P> Future for Pin<P> where
    P: Unpin + DerefMut,
    <P as Deref>::Target: Future,  type Output = <<P as Deref>::Target as Future>::Output;

fn clone(&self) -> Pin<P>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<P, Q> PartialOrd<Pin<Q>> for Pin<P> where
    P: PartialOrd<Q>, 

fn partial_cmp(&self, other: &Pin<Q>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Pin<Q>) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Pin<Q>) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Pin<Q>) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Pin<Q>) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<P, U> CoerceUnsized<Pin<U>> for Pin<P> where
    P: CoerceUnsized<U>, 

impl<P> Copy for Pin<P> where
    P: Copy, 

impl<P> DerefMut for Pin<P> where
    P: DerefMut,
    <P as Deref>::Target: Unpin, 

fn deref_mut(&mut self) -> &mut <P as Deref>::Target

Mutably dereferences the value.

impl<P> Eq for Pin<P> where
    P: Eq, 

impl<'_, G> Generator for Pin<&'_ mut G> where
    G: Generator + ?Sized, 

type Yield = <G as Generator>::Yield

🔬 This is a nightly-only experimental API. (generator_trait)

The type of value this generator yields.

type Return = <G as Generator>::Return

🔬 This is a nightly-only experimental API. (generator_trait)

The type of value this generator returns.

fn resume(
    self: Pin<&mut Pin<&'_ mut G>>
) -> GeneratorState<<Pin<&'_ mut G> as Generator>::Yield, <Pin<&'_ mut G> as Generator>::Return>

🔬 This is a nightly-only experimental API. (generator_trait)

Resumes the execution of this generator.

impl<T> From<Box<T>> for Pin<Box<T>> where
    T: ?Sized, 

Important traits for Pin<P>

impl<P> Future for Pin<P> where
    P: Unpin + DerefMut,
    <P as Deref>::Target: Future,  type Output = <<P as Deref>::Target as Future>::Output;

fn from(boxed: Box<T>) -> Pin<Box<T>>

Converts a Box<T> into a Pin<Box<T>>

This conversion does not allocate on the heap and happens in place.

impl<G> Generator for Pin<Box<G>> where
    G: Generator + ?Sized, 

type Yield = <G as Generator>::Yield

🔬 This is a nightly-only experimental API. (generator_trait)

The type of value this generator yields.

type Return = <G as Generator>::Return

🔬 This is a nightly-only experimental API. (generator_trait)

The type of value this generator returns.

fn resume(
    self: Pin<&mut Pin<Box<G>>>
) -> GeneratorState<<Pin<Box<G>> as Generator>::Yield, <Pin<Box<G>> as Generator>::Return>

🔬 This is a nightly-only experimental API. (generator_trait)

Resumes the execution of this generator.

impl<P> Stream for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: Stream, 

type Item = <<P as Deref>::Target as Stream>::Item

Values yielded by the stream.

fn poll_next(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context
) -> Poll<Option<<Pin<P> as Stream>::Item>>

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream.

impl<P> FusedFuture for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: FusedFuture, 

fn is_terminated(&self) -> bool

Returns true if the underlying future should no longer be polled.

impl<P> FusedStream for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: FusedStream, 

fn is_terminated(&self) -> bool

Returns true if the stream should no longer be polled.

impl<P> FusedFuture for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: FusedFuture, 

fn is_terminated(&self) -> bool

Returns true if the underlying future should no longer be polled.

impl<'a, T, F> UnsafeFutureObj<'a, T> for Pin<Box<F>> where
    F: Future<Output = T> + 'a, 

fn into_raw(self) -> *mut dyn Future<Output = T> + 'a

Convert an owned instance into a (conceptually owned) fat pointer.

unsafe fn drop(ptr: *mut dyn Future<Output = T> + 'a)

Drops the future represented by the given fat pointer.

impl<'a, T> UnsafeFutureObj<'a, T> for Pin<Box<dyn Future<Output = T> + 'a>> where
    T: 'a, 

fn into_raw(self) -> *mut dyn Future<Output = T> + 'a

Convert an owned instance into a (conceptually owned) fat pointer.

unsafe fn drop(ptr: *mut dyn Future<Output = T> + 'a)

Drops the future represented by the given fat pointer.

impl<'a, T> UnsafeFutureObj<'a, T> for Pin<Box<dyn Future<Output = T> + 'a + Send>> where
    T: 'a, 

fn into_raw(self) -> *mut dyn Future<Output = T> + 'a

Convert an owned instance into a (conceptually owned) fat pointer.

unsafe fn drop(ptr: *mut dyn Future<Output = T> + 'a)

Drops the future represented by the given fat pointer.

impl<'a, T, F> UnsafeFutureObj<'a, T> for Pin<&'a mut F> where
    F: Future<Output = T> + 'a, 

fn into_raw(self) -> *mut dyn Future<Output = T> + 'a

Convert an owned instance into a (conceptually owned) fat pointer.

unsafe fn drop(_ptr: *mut dyn Future<Output = T> + 'a)

Drops the future represented by the given fat pointer.

impl<'a, T> UnsafeFutureObj<'a, T> for Pin<&'a mut (dyn Future<Output = T> + 'a)>

fn into_raw(self) -> *mut dyn Future<Output = T> + 'a

Convert an owned instance into a (conceptually owned) fat pointer.

unsafe fn drop(_ptr: *mut dyn Future<Output = T> + 'a)

Drops the future represented by the given fat pointer.

impl<P> Stream for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: Stream, 

type Item = <<P as Deref>::Target as Stream>::Item

Values yielded by the stream.

fn poll_next(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context
) -> Poll<Option<<Pin<P> as Stream>::Item>>

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream.

impl<P> FusedStream for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: FusedStream, 

fn is_terminated(&self) -> bool

Returns true if the stream should no longer be polled.

impl<P, Item> Sink<Item> for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: Sink<Item>, 

type Error = <<P as Deref>::Target as Sink<Item>>::Error

The type of value produced by the sink when an error occurs.

fn poll_ready(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context
) -> Poll<Result<(), <Pin<P> as Sink<Item>>::Error>>

Attempts to prepare the Sink to receive a value.

fn start_send(
    self: Pin<&mut Pin<P>>,
    item: Item
) -> Result<(), <Pin<P> as Sink<Item>>::Error>

Begin the process of sending a value to the sink. Each call to this function must be preceded by a successful call to poll_ready which returned Poll::Ready(Ok(())).

fn poll_flush(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context
) -> Poll<Result<(), <Pin<P> as Sink<Item>>::Error>>

Flush any remaining output from this sink.

fn poll_close(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context
) -> Poll<Result<(), <Pin<P> as Sink<Item>>::Error>>

Flush any remaining output and close this sink, if necessary.

impl<P> AsyncWrite for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: AsyncWrite, 

fn poll_write(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context,
    buf: &[u8]
) -> Poll<Result<usize, Error>>

Attempt to write bytes from buf into the object.

fn poll_write_vectored(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context,
    bufs: &[IoSlice]
) -> Poll<Result<usize, Error>>

Attempt to write bytes from bufs into the object using vectored IO operations.

fn poll_flush(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context
) -> Poll<Result<(), Error>>

Attempt to flush the object, ensuring that any buffered data reach their destination.

fn poll_close(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context
) -> Poll<Result<(), Error>>

Attempt to close the object.

impl<P> AsyncSeek for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: AsyncSeek, 

fn poll_seek(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context,
    pos: SeekFrom
) -> Poll<Result<u64, Error>>

Attempt to seek to an offset, in bytes, in a stream.

impl<P> AsyncRead for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: AsyncRead, 

fn poll_read(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context,
    buf: &mut [u8]
) -> Poll<Result<usize, Error>>

Attempt to read from the AsyncRead into buf.

fn poll_read_vectored(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context,
    bufs: &mut [IoSliceMut]
) -> Poll<Result<usize, Error>>

Attempt to read from the AsyncRead into bufs using vectored IO operations.

impl<P> AsyncBufRead for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: AsyncBufRead, 

fn poll_fill_buf(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context
) -> Poll<Result<&[u8], Error>>

Attempt to return the contents of the internal buffer, filling it with more data from the inner reader if it is empty.

fn consume(self: Pin<&mut Pin<P>>, amt: usize)

Tells this buffer that amt bytes have been consumed from the buffer, so they should no longer be returned in calls to [poll_read].

impl<P> Future for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: Future, 

type Output = <<P as Deref>::Target as Future>::Output

The type of value produced on completion.

fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output>

Attempt to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.

fn delay(self, dur: Duration) -> ImplFuture<Self::Output> where
    Self: Future + Sized, 

This is supported on unstable only.

Returns a Future that delays execution for a specified time.

fn flatten(self) -> ImplFuture<<Self::Output as IntoFuture>::Output> where
    Self: Future + Sized,
    Self::Output: IntoFuture, 

This is supported on unstable only.

Flatten out the execution of this future when the result itself can be converted into another future.

fn race<F>(self, other: F) -> ImplFuture<Self::Output> where
    Self: Future + Sized,
    F: Future<Output = Self::Output>, 

This is supported on unstable only.

Waits for one of two similarly-typed futures to complete.

fn try_race<F: Future, T, E>(self, other: F) -> ImplFuture<Self::Output> where
    Self: Future<Output = Result<T, E>> + Sized,
    F: Future<Output = Self::Output>, 

This is supported on unstable only.

Waits for one of two similarly-typed fallible futures to complete.

impl<P> BufRead for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: BufRead, 

fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<&[u8]>>

Returns the contents of the internal buffer, filling it with more data from the inner reader if it is empty.

fn consume(self: Pin<&mut Self>, amt: usize)

Tells this buffer that amt bytes have been consumed from the buffer, so they should no longer be returned in calls to read.

fn read_until<'a>(
    &'a mut self,
    byte: u8,
    buf: &'a mut Vec<u8>
) -> ImplFuture<usize> where
    Self: Unpin, 

Reads all bytes into buf until the delimiter byte or EOF is reached.

fn read_line<'a>(&'a mut self, buf: &'a mut String) -> ImplFuture<Result<usize>> where
    Self: Unpin, 

Reads all bytes and appends them into buf until a newline (the 0xA byte) is reached.

fn lines(self) -> Lines<Self> where
    Self: Unpin + Sized, 

Returns a stream over the lines of this byte stream.

fn split(self, byte: u8) -> Split<Self> where
    Self: Sized, 

Returns a stream over the contents of this reader split on the byte byte.

impl<P> Read for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: Read, 

fn poll_read(
    self: Pin<&mut Self>,
    cx: &mut Context,
    buf: &mut [u8]
) -> Poll<Result<usize>>

Attempt to read from the AsyncRead into buf.

fn poll_read_vectored(
    self: Pin<&mut Self>,
    cx: &mut Context,
    bufs: &mut [IoSliceMut]
) -> Poll<Result<usize>>

Attempt to read from the AsyncRead into bufs using vectored IO operations.

fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> ImplFuture<Result<usize>> where
    Self: Unpin, 

Reads some bytes from the byte stream.

fn read_vectored<'a>(
    &'a mut self,
    bufs: &'a mut [IoSliceMut<'a>]
) -> ImplFuture<Result<usize>> where
    Self: Unpin, 

Like [read], except that it reads into a slice of buffers.

fn read_to_end<'a>(
    &'a mut self,
    buf: &'a mut Vec<u8>
) -> ImplFuture<Result<usize>> where
    Self: Unpin, 

Reads all bytes from the byte stream.

fn read_to_string<'a>(
    &'a mut self,
    buf: &'a mut String
) -> ImplFuture<Result<usize>> where
    Self: Unpin, 

Reads all bytes from the byte stream and appends them into a string.

fn read_exact<'a>(&'a mut self, buf: &'a mut [u8]) -> ImplFuture<Result<()>> where
    Self: Unpin, 

Reads the exact number of bytes required to fill buf.

fn take(self, limit: u64) -> Take<Self> where
    Self: Sized, 

Creates an adaptor which will read at most limit bytes from it.

fn by_ref(&mut self) -> &mut Self where
    Self: Sized, 

Creates a "by reference" adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self> where
    Self: Sized, 

Transforms this Read instance to a Stream over its bytes.

fn chain<R: Read>(self, next: R) -> Chain<Self, R> where
    Self: Sized, 

Creates an adaptor which will chain this stream with another.

impl<P> Seek for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: Seek, 

fn poll_seek(
    self: Pin<&mut Self>,
    cx: &mut Context,
    pos: SeekFrom
) -> Poll<Result<u64>>

Attempt to seek to an offset, in bytes, in a stream.

fn seek(&mut self, pos: SeekFrom) -> ImplFuture<Result<u64>> where
    Self: Unpin, 

Seeks to a new position in a byte stream.

impl<P> Write for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: Write, 

fn poll_write(
    self: Pin<&mut Self>,
    cx: &mut Context,
    buf: &[u8]
) -> Poll<Result<usize>>

Attempt to write bytes from buf into the object.

fn poll_flush(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<()>>

Attempt to flush the object, ensuring that any buffered data reach their destination.

fn poll_close(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<()>>

Attempt to close the object.

fn poll_write_vectored(
    self: Pin<&mut Self>,
    cx: &mut Context,
    bufs: &[IoSlice]
) -> Poll<Result<usize>>

Attempt to write bytes from bufs into the object using vectored IO operations.

fn write<'a>(&'a mut self, buf: &'a [u8]) -> ImplFuture<Result<usize>> where
    Self: Unpin, 

Writes some bytes into the byte stream.

fn flush(&mut self) -> ImplFuture<Result<()>> where
    Self: Unpin, 

Flushes the stream to ensure that all buffered contents reach their destination.

fn write_vectored<'a>(
    &'a mut self,
    bufs: &'a [IoSlice<'a>]
) -> ImplFuture<Result<usize>> where
    Self: Unpin, 

Like [write], except that it writes from a slice of buffers.

fn write_all<'a>(&'a mut self, buf: &'a [u8]) -> ImplFuture<Result<()>> where
    Self: Unpin, 

Writes an entire buffer into the byte stream.

fn write_fmt<'a>(&'a mut self, fmt: Arguments) -> ImplFuture<Result<()>> where
    Self: Unpin, 

Writes a formatted string into this writer, returning any error encountered.

impl<P> Stream for Pin<P> where
    P: DerefMut + Unpin,
    <P as Deref>::Target: Stream, 

type Item = <<P as Deref>::Target as Stream>::Item

The type of items yielded by this stream.

fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>>

Attempts to receive the next item from the stream.

fn next(&mut self) -> ImplFuture<Option<Self::Item>> where
    Self: Unpin, 

Advances the stream and returns the next value.

fn take(self, n: usize) -> Take<Self> where
    Self: Sized, 

Creates a stream that yields its first n elements.

fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P, Self::Item> where
    Self: Sized,
    P: FnMut(&Self::Item) -> bool, 

Creates a stream that yields elements based on a predicate.

fn step_by(self, step: usize) -> StepBy<Self> where
    Self: Sized, 

Creates a stream that yields each stepth element.

fn chain<U>(self, other: U) -> Chain<Self, U> where
    Self: Sized,
    U: Stream<Item = Self::Item> + Sized, 

Takes two streams and creates a new stream over both in sequence.

fn cloned<'a, T>(self) -> Cloned<Self> where
    Self: Sized + Stream<Item = &'a T>,
    T: 'a + Clone, 

Creates an stream which copies all of its elements.

fn copied<'a, T>(self) -> Copied<Self> where
    Self: Sized + Stream<Item = &'a T>,
    T: 'a + Copy, 

Creates an stream which copies all of its elements.

fn cycle(self) -> Cycle<Self, Self::Item> where
    Self: Sized,
    Self::Item: Clone, 

Creates a stream that yields the provided values infinitely and in order.

fn enumerate(self) -> Enumerate<Self> where
    Self: Sized, 

Creates a stream that gives the current element's count as well as the next value.

fn map<B, F>(self, f: F) -> Map<Self, F, Self::Item, B> where
    Self: Sized,
    F: FnMut(Self::Item) -> B, 

Takes a closure and creates a stream that calls that closure on every element of this stream.

fn inspect<F>(self, f: F) -> Inspect<Self, F, Self::Item> where
    Self: Sized,
    F: FnMut(&Self::Item), 

A combinator that does something with each element in the stream, passing the value on.

fn last(self) -> ImplFuture<Option<Self::Item>> where
    Self: Sized, 

Returns the last element of the stream.

fn fuse(self) -> Fuse<Self> where
    Self: Sized, 

Creates a stream which ends after the first None.

fn filter<P>(self, predicate: P) -> Filter<Self, P, Self::Item> where
    Self: Sized,
    P: FnMut(&Self::Item) -> bool, 

Creates a stream that uses a predicate to determine if an element should be yielded.

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, Self::Item, F> where
    Self: Sized,
    U: IntoStream,
    F: FnMut(Self::Item) -> U, 

This is supported on unstable only.

Creates an stream that works like map, but flattens nested structure.

fn flatten(self) -> Flatten<Self, Self::Item> where
    Self: Sized,
    Self::Item: IntoStream, 

This is supported on unstable only.

Creates an stream that flattens nested structure.

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F, Self::Item, B> where
    Self: Sized,
    F: FnMut(Self::Item) -> Option<B>, 

Both filters and maps a stream.

fn min_by_key<K>(self, key_by: K) -> ImplFuture<Option<Self::Item>> where
    Self: Sized,
    Self::Item: Ord,
    K: FnMut(&Self::Item) -> Self::Item, 

Returns the element that gives the minimum value with respect to the specified key function. If several elements are equally minimum, the first element is returned. If the stream is empty, None is returned.

fn max_by_key<K>(self, key_by: K) -> ImplFuture<Option<Self::Item>> where
    Self: Sized,
    Self::Item: Ord,
    K: FnMut(&Self::Item) -> Self::Item, 

Returns the element that gives the maximum value with respect to the specified key function. If several elements are equally maximum, the first element is returned. If the stream is empty, None is returned.

fn min_by<F>(self, compare: F) -> ImplFuture<Option<Self::Item>> where
    Self: Sized,
    F: FnMut(&Self::Item, &Self::Item) -> Ordering, 

Returns the element that gives the minimum value with respect to the specified comparison function. If several elements are equally minimum, the first element is returned. If the stream is empty, None is returned.

fn min<F>(self) -> ImplFuture<Option<Self::Item>> where
    Self: Sized,
    F: FnMut(&Self::Item, &Self::Item) -> Ordering, 

Returns the element that gives the minimum value. If several elements are equally minimum, the first element is returned. If the stream is empty, None is returned.

fn max_by<F>(self, compare: F) -> ImplFuture<Option<Self::Item>> where
    Self: Sized,
    F: FnMut(&Self::Item, &Self::Item) -> Ordering, 

Returns the element that gives the maximum value with respect to the specified comparison function. If several elements are equally maximum, the first element is returned. If the stream is empty, None is returned.

fn nth(&mut self, n: usize) -> ImplFuture<Option<Self::Item>> where
    Self: Sized, 

Returns the nth element of the stream.

fn all<F>(&mut self, f: F) -> ImplFuture<bool> where
    Self: Unpin + Sized,
    F: FnMut(Self::Item) -> bool, 

Tests if every element of the stream matches a predicate.

fn find<P>(&mut self, p: P) -> ImplFuture<Option<Self::Item>> where
    Self: Sized,
    P: FnMut(&Self::Item) -> bool, 

Searches for an element in a stream that satisfies a predicate.

fn find_map<F, B>(&mut self, f: F) -> ImplFuture<Option<B>> where
    Self: Sized,
    F: FnMut(Self::Item) -> Option<B>, 

Applies function to the elements of stream and returns the first non-none result.

fn fold<B, F>(self, init: B, f: F) -> ImplFuture<B> where
    Self: Sized,
    F: FnMut(B, Self::Item) -> B, 

A combinator that applies a function to every element in a stream producing a single, final value.

fn for_each<F>(self, f: F) -> ImplFuture<()> where
    Self: Sized,
    F: FnMut(Self::Item), 

Call a closure on each element of the stream.

fn any<F>(&mut self, f: F) -> ImplFuture<bool> where
    Self: Unpin + Sized,
    F: FnMut(Self::Item) -> bool, 

Tests if any element of the stream matches a predicate.

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where
    Self: Sized,
    F: FnMut(&mut St, Self::Item) -> Option<B>, 

A stream adaptor similar to [fold] that holds internal state and produces a new stream.

fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P, Self::Item> where
    Self: Sized,
    P: FnMut(&Self::Item) -> bool, 

Combinator that skips elements based on a predicate.

fn skip(self, n: usize) -> Skip<Self> where
    Self: Sized, 

Creates a combinator that skips the first n elements.

fn timeout(self, dur: Duration) -> Timeout<Self> where
    Self: Stream + Sized, 

This is supported on unstable only.

Await a stream or times out after a duration of time.

fn try_fold<B, F, T, E>(self, init: T, f: F) -> ImplFuture<Result<T, E>> where
    Self: Sized,
    F: FnMut(B, Self::Item) -> Result<T, E>, 

A combinator that applies a function as long as it returns successfully, producing a single, final value. Immediately returns the error when the function returns unsuccessfully.

fn try_for_each<F, E>(self, f: F) -> ImplFuture<E> where
    Self: Sized,
    F: FnMut(Self::Item) -> Result<(), E>, 

Applies a falliable function to each element in a stream, stopping at first error and returning it.

fn zip<U>(self, other: U) -> Zip<Self, U> where
    Self: Sized + Stream,
    U: Stream, 

'Zips up' two streams into a single stream of pairs.

#[must_use = "if you really need to exhaust the iterator, consider `.for_each(drop)` instead (TODO)"] fn collect<'a, B>(self) -> ImplFuture<B> where
    Self: Sized + 'a,
    B: FromStream<Self::Item>, 

This is supported on unstable only.

Transforms a stream into a collection.

fn merge<U>(self, other: U) -> Merge<Self, U> where
    Self: Sized,
    U: Stream<Item = Self::Item> + Sized, 

This is supported on unstable only.

Combines multiple streams into a single stream of all their outputs.

fn partial_cmp<S>(self, other: S) -> ImplFuture<Option<Ordering>> where
    Self: Sized + Stream,
    S: Stream,
    Self::Item: PartialOrd<S::Item>, 

Lexicographically compares the elements of this Stream with those of another.

fn position<P>(self, predicate: P) -> ImplFuture<Option<usize>> where
    Self: Sized,
    P: FnMut(&Self::Item) -> bool, 

Searches for an element in a Stream that satisfies a predicate, returning its index.

fn cmp<S>(self, other: S) -> ImplFuture<Ordering> where
    Self: Sized + Stream,
    S: Stream,
    Self::Item: Ord, 

Lexicographically compares the elements of this Stream with those of another using 'Ord'.

fn ne<S>(self, other: S) -> ImplFuture<bool> where
    Self: Sized + Stream,
    S: Sized + Stream,
    Self::Item: PartialEq<S::Item>, 

Determines if the elements of this Stream are lexicographically not equal to those of another. # Examples ``` # fn main() { async_std::task::block_on(async { # use async_std::prelude::*; use async_std::stream;

fn ge<S>(self, other: S) -> ImplFuture<bool> where
    Self: Sized + Stream,
    S: Stream,
    Self::Item: PartialOrd<S::Item>, 

Determines if the elements of this Stream are lexicographically greater than or equal to those of another.

fn eq<S>(self, other: S) -> ImplFuture<bool> where
    Self: Sized + Stream,
    S: Sized + Stream,
    Self::Item: PartialEq<S::Item>, 

Determines if the elements of this Stream are lexicographically equal to those of another.

fn gt<S>(self, other: S) -> ImplFuture<bool> where
    Self: Sized + Stream,
    S: Stream,
    Self::Item: PartialOrd<S::Item>, 

Determines if the elements of this Stream are lexicographically greater than those of another.

fn le<S>(self, other: S) -> ImplFuture<bool> where
    Self: Sized + Stream,
    S: Stream,
    Self::Item: PartialOrd<S::Item>, 

Determines if the elements of this Stream are lexicographically less or equal to those of another.

fn lt<S>(self, other: S) -> ImplFuture<bool> where
    Self: Sized + Stream,
    S: Stream,
    Self::Item: PartialOrd<S::Item>, 

Determines if the elements of this Stream are lexicographically less than those of another.

fn sum<'a, S>(self) -> ImplFuture<S> where
    Self: Sized + Stream<Item = S> + 'a,
    S: Sum, 

This is supported on unstable only.

Sums the elements of an iterator.

fn product<'a, P>(self) -> ImplFuture<P> where
    Self: Sized + Stream<Item = P> + 'a,
    P: Product, 

This is supported on unstable only.

Iterates over the entire iterator, multiplying all the elements