pub struct BorrowedCursor<'a, T> { /* private fields */ }core_io_borrowed_buf)Expand description
A writeable view of the unfilled portion of a BorrowedBuf.
The unfilled portion may be uninitialized; see BorrowedBuf for details.
Data can be written directly to the cursor by using append or
indirectly by getting a slice of part or all of the cursor and writing into the slice. In the
indirect case, the caller must call advance after writing to inform
the cursor how many elements have been written.
Once elements are written to the cursor, they become part of the filled portion of the
underlying BorrowedBuf and can no longer be accessed or re-written by the cursor. In other
words, the cursor tracks the unfilled part of the underlying BorrowedBuf.
The lifetime 'a is a bound on the lifetime of the underlying buffer (which means it is a bound
on the elements in that buffer by transitivity).
Implementations§
Source§impl<'a, T> BorrowedCursor<'a, T>where
T: Copy,
impl<'a, T> BorrowedCursor<'a, T>where
T: Copy,
Sourcepub fn reborrow<'this>(&'this mut self) -> BorrowedCursor<'this, T>
🔬This is a nightly-only experimental API. (core_io_borrowed_buf)
pub fn reborrow<'this>(&'this mut self) -> BorrowedCursor<'this, T>
core_io_borrowed_buf)Reborrows this cursor by cloning it with a smaller lifetime.
Since a cursor maintains unique access to its underlying buffer, the borrowed cursor is not accessible while the new cursor exists.
Sourcepub fn capacity(&self) -> usize
🔬This is a nightly-only experimental API. (core_io_borrowed_buf)
pub fn capacity(&self) -> usize
core_io_borrowed_buf)Returns the available space in the cursor.
Sourcepub fn written(&self) -> usize
🔬This is a nightly-only experimental API. (core_io_borrowed_buf)
pub fn written(&self) -> usize
core_io_borrowed_buf)Returns the number of elements written to the BorrowedBuf this cursor was created from.
In particular, the count returned is shared by all reborrows of the cursor.
Sourcepub fn is_init(&self) -> bool
🔬This is a nightly-only experimental API. (borrowed_buf_init)
pub fn is_init(&self) -> bool
borrowed_buf_init)Returns true if the buffer is initialized.
Sourcepub unsafe fn set_init(&mut self)
🔬This is a nightly-only experimental API. (borrowed_buf_init)
pub unsafe fn set_init(&mut self)
borrowed_buf_init)Sourcepub unsafe fn as_mut(&mut self) -> &mut [MaybeUninit<T>]
🔬This is a nightly-only experimental API. (core_io_borrowed_buf)
pub unsafe fn as_mut(&mut self) -> &mut [MaybeUninit<T>]
core_io_borrowed_buf)Returns a mutable reference to the whole cursor.
§Safety
The caller must not uninitialize any elements of the cursor if it is initialized.
Sourcepub fn advance_checked(&mut self, n: usize) -> &mut BorrowedCursor<'a, T>
🔬This is a nightly-only experimental API. (borrowed_buf_init)
pub fn advance_checked(&mut self, n: usize) -> &mut BorrowedCursor<'a, T>
borrowed_buf_init)Advances the cursor by asserting that n elements have been filled.
After advancing, the n elements are no longer accessible via the cursor and can only be
accessed via the underlying buffer. I.e., the buffer’s filled portion grows by n elements
and its unfilled portion (and the capacity of this cursor) shrinks by n elements.
If less than n elements initialized (by the cursor’s point of view), set_init should be
called first.
§Panics
Panics if there are less than n elements initialized.
Sourcepub unsafe fn advance(&mut self, n: usize) -> &mut BorrowedCursor<'a, T>
🔬This is a nightly-only experimental API. (core_io_borrowed_buf)
pub unsafe fn advance(&mut self, n: usize) -> &mut BorrowedCursor<'a, T>
core_io_borrowed_buf)Advances the cursor by asserting that n elements have been filled.
After advancing, the n elements are no longer accessible via the cursor and can only be
accessed via the underlying buffer. I.e., the buffer’s filled portion grows by n elements
and its unfilled portion (and the capacity of this cursor) shrinks by n elements.
§Safety
The caller must ensure that the first n elements of the cursor have been initialized.
Sourcepub fn append(&mut self, buf: &[T])
🔬This is a nightly-only experimental API. (core_io_borrowed_buf)
pub fn append(&mut self, buf: &[T])
core_io_borrowed_buf)Append elements to the cursor, advancing position within its buffer.
§Panics
Panics if self.capacity() is less than buf.len().
Sourcepub fn with_unfilled_buf<R>(
&mut self,
f: impl FnOnce(&mut BorrowedBuf<'_, T>) -> R,
) -> R
🔬This is a nightly-only experimental API. (core_io_borrowed_buf)
pub fn with_unfilled_buf<R>( &mut self, f: impl FnOnce(&mut BorrowedBuf<'_, T>) -> R, ) -> R
core_io_borrowed_buf)Runs the given closure with a BorrowedBuf containing the unfilled part
of the cursor.
This enables inspecting what was written to the cursor.
§Panics
Panics if the BorrowedBuf given to the closure is replaced by another
one.
Source§impl<'a, T> BorrowedCursor<'a, T>
impl<'a, T> BorrowedCursor<'a, T>
Sourcepub fn ensure_init(&mut self) -> &mut [T]
🔬This is a nightly-only experimental API. (borrowed_buf_init)
pub fn ensure_init(&mut self) -> &mut [T]
borrowed_buf_init)Initializes all elements in the cursor with their default value and returns them.
Trait Implementations§
Source§impl<T> Debug for BorrowedCursor<'_, T>
impl<T> Debug for BorrowedCursor<'_, T>
Source§impl<'data, T> From<BorrowedCursor<'data, T>> for BorrowedBuf<'data, T>where
T: Copy,
Creates a new BorrowedBuf from a cursor.
impl<'data, T> From<BorrowedCursor<'data, T>> for BorrowedBuf<'data, T>where
T: Copy,
Creates a new BorrowedBuf from a cursor.
Use BorrowedCursor::with_unfilled_buf instead for a safer alternative.
Source§fn from(buf: BorrowedCursor<'data, T>) -> BorrowedBuf<'data, T>
fn from(buf: BorrowedCursor<'data, T>) -> BorrowedBuf<'data, T>
impl<T> Send for BorrowedCursor<'_, T>where
T: Send,
impl<T> Sync for BorrowedCursor<'_, T>where
T: Sync,
Source§impl<'a> Write for BorrowedCursor<'a, u8>
impl<'a> Write for BorrowedCursor<'a, u8>
Source§fn write(&mut self, buf: &[u8]) -> Result<usize, Error>
fn write(&mut self, buf: &[u8]) -> Result<usize, Error>
Source§fn is_write_vectored(&self) -> bool
fn is_write_vectored(&self) -> bool
can_vector)Source§fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>
fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>
Source§fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>
fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>
write_all_vectored)Source§fn flush(&mut self) -> Result<(), Error>
fn flush(&mut self) -> Result<(), Error>
Auto Trait Implementations§
impl<'a, T> Forget for BorrowedCursor<'a, T>
impl<'a, T> Freeze for BorrowedCursor<'a, T>
impl<'a, T> RefUnwindSafe for BorrowedCursor<'a, T>
impl<'a, T> Unpin for BorrowedCursor<'a, T>
impl<'a, T> UnsafeUnpin for BorrowedCursor<'a, T>
impl<'a, T> UnwindSafe for BorrowedCursor<'a, T>
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
impl<ST, DT> CastableFrom<ST, Initialized, Initialized> for DT
impl<ST, DT> CastableFrom<ST, Uninit, Uninit> for DT
§impl<T> ExecutableCommand for T
impl<T> ExecutableCommand for T
§fn execute(&mut self, command: impl Command) -> Result<&mut T, Error>
fn execute(&mut self, command: impl Command) -> Result<&mut T, Error>
Executes the given command directly.
The given command its ANSI escape code will be written and flushed onto Self.
§Arguments
-
The command that you want to execute directly.
§Example
use std::io;
use crossterm::{ExecutableCommand, style::Print};
fn main() -> io::Result<()> {
// will be executed directly
io::stdout()
.execute(Print("sum:\n".to_string()))?
.execute(Print(format!("1 + 1= {} ", 1 + 1)))?;
Ok(())
// ==== Output ====
// sum:
// 1 + 1 = 2
}Have a look over at the Command API for more details.
§Notes
- In the case of UNIX and Windows 10, ANSI codes are written to the given ‘writer’.
- In case of Windows versions lower than 10, a direct WinAPI call will be made.
The reason for this is that Windows versions lower than 10 do not support ANSI codes,
and can therefore not be written to the given
writer. Therefore, there is no difference between execute and queue for those old Windows versions.
§impl<T> Instrument for T
impl<T> Instrument for T
§fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
§fn in_current_span(self) -> Instrumented<Self> ⓘ
fn in_current_span(self) -> Instrumented<Self> ⓘ
Source§impl<T> IntoEither for T
impl<T> IntoEither for T
Source§fn into_either(self, into_left: bool) -> Either<Self, Self> ⓘ
fn into_either(self, into_left: bool) -> Either<Self, Self> ⓘ
self into a Left variant of Either<Self, Self>
if into_left is true.
Converts self into a Right variant of Either<Self, Self>
otherwise. Read moreSource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self> ⓘ
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self> ⓘ
self into a Left variant of Either<Self, Self>
if into_left(&self) returns true.
Converts self into a Right variant of Either<Self, Self>
otherwise. Read moreimpl<T> Message for Twhere
T: Send + 'static,
§impl<T> Pointable for T
impl<T> Pointable for T
§impl<T> QueueableCommand for T
impl<T> QueueableCommand for T
§fn queue(&mut self, command: impl Command) -> Result<&mut T, Error>
fn queue(&mut self, command: impl Command) -> Result<&mut T, Error>
Queues the given command for further execution.
Queued commands will be executed in the following cases:
- When
flushis called manually on the given type implementingio::Write. - The terminal will
flushautomatically if the buffer is full. - Each line is flushed in case of
stdout, because it is line buffered.
§Arguments
-
The command that you want to queue for later execution.
§Examples
use std::io::{self, Write};
use crossterm::{QueueableCommand, style::Print};
fn main() -> io::Result<()> {
let mut stdout = io::stdout();
// `Print` will executed executed when `flush` is called.
stdout
.queue(Print("foo 1\n".to_string()))?
.queue(Print("foo 2".to_string()))?;
// some other code (no execution happening here) ...
// when calling `flush` on `stdout`, all commands will be written to the stdout and therefore executed.
stdout.flush()?;
Ok(())
// ==== Output ====
// foo 1
// foo 2
}Have a look over at the Command API for more details.
§Notes
- In the case of UNIX and Windows 10, ANSI codes are written to the given ‘writer’.
- In case of Windows versions lower than 10, a direct WinAPI call will be made.
The reason for this is that Windows versions lower than 10 do not support ANSI codes,
and can therefore not be written to the given
writer. Therefore, there is no difference between execute and queue for those old Windows versions.
impl<T> Read<Exclusive, BecauseExclusive> for Twhere
T: ?Sized,
§impl<W> SynchronizedUpdate for W
impl<W> SynchronizedUpdate for W
§fn sync_update<T>(
&mut self,
operations: impl FnOnce(&mut W) -> T,
) -> Result<T, Error>
fn sync_update<T>( &mut self, operations: impl FnOnce(&mut W) -> T, ) -> Result<T, Error>
Performs a set of actions within a synchronous update.
Updates will be suspended in the terminal, the function will be executed against self, updates will be resumed, and a flush will be performed.
§Arguments
-
Function
A function that performs the operations that must execute in a synchronized update.
§Examples
use std::io;
use crossterm::{ExecutableCommand, SynchronizedUpdate, style::Print};
fn main() -> io::Result<()> {
let mut stdout = io::stdout();
stdout.sync_update(|stdout| {
stdout.execute(Print("foo 1\n".to_string()))?;
stdout.execute(Print("foo 2".to_string()))?;
// The effects of the print command will not be present in the terminal
// buffer, but not visible in the terminal.
std::io::Result::Ok(())
})?;
// The effects of the commands will be visible.
Ok(())
// ==== Output ====
// foo 1
// foo 2
}§Notes
This command is performed only using ANSI codes, and will do nothing on terminals that do not support ANSI codes, or this specific extension.
When rendering the screen of the terminal, the Emulator usually iterates through each visible grid cell and renders its current state. With applications updating the screen a at higher frequency this can cause tearing.
This mode attempts to mitigate that.
When the synchronization mode is enabled following render calls will keep rendering the last rendered state. The terminal Emulator keeps processing incoming text and sequences. When the synchronized update mode is disabled again the renderer may fetch the latest screen buffer state again, effectively avoiding the tearing effect by unintentionally rendering in the middle a of an application screen update.