Trait mycelium_util::io::Write

pub trait Write {
    // Required methods
    fn write(&mut self, buf: &[u8]) -> Result<usize>;
    fn flush(&mut self) -> Result<()>;

    // Provided methods
    fn write_all(&mut self, buf: &[u8]) -> Result<()> { ... }
    fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<()> { ... }
    fn by_ref(&mut self) -> &mut Self
       where Self: Sized { ... }
}

A trait for objects which are byte-oriented sinks.

Implementors of the Write trait are sometimes called ‘writers’.

Writers are defined by two required methods, write and flush:

• The write method will attempt to write some data into the object, returning how many bytes were successfully written.

• The flush method is useful for adapters and explicit buffers themselves for ensuring that all buffered data has been pushed out to the ‘true sink’.

This is essentially a vendored version of the std::io::Write trait from the Rust standard library, modified to work without std. See the module-level docs for mycelium_util::io for more information on how mycelium_util’s io module differs from std’s.

Required Methods

fn write(&mut self, buf: &[u8]) -> Result<usize>

Write a buffer into this writer, returning how many bytes were written.

This function will attempt to write the entire contents of buf, but the entire write may not succeed, or the write may also generate an error. A call to write represents at most one attempt to write to any wrapped object.

Calls to write are not guaranteed to block waiting for data to be written, and a write which would otherwise block can be indicated through an Err variant.

If the return value is Ok(n) then it must be guaranteed that n <= buf.len(). A return value of 0 typically means that the underlying object is no longer able to accept bytes and will likely not be able to in the future as well, or that the buffer provided is empty.

Errors

Each call to write may generate an I/O error indicating that the operation could not be completed. If an error is returned then no bytes in the buffer were written to this writer.

It is not considered an error if the entire buffer could not be written to this writer.

An error of the ErrorKind::Interrupted kind is non-fatal and the write operation should be retried if there is nothing else to do.

fn flush(&mut self) -> Result<()>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

Provided Methods

fn write_all(&mut self, buf: &[u8]) -> Result<()>

Attempts to write an entire buffer into this writer.

This method will continuously call write until there is no more data to be written or an error of non-ErrorKind::Interrupted kind is returned. This method will not return until the entire buffer has been successfully written or such an error occurs. The first error that is not of ErrorKind::Interrupted kind generated from this method will be returned.

Errors

This function will return the first error of non-ErrorKind::Interrupted kind that write returns.

fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<()>

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

This method is primarily used to interface with the format_args! macro, but it is rare that this should explicitly be called. The write! macro should be favored to invoke this method instead.

This function internally uses the write_all method on this trait and hence will continuously write data so long as no errors are received. This also means that partial writes are not indicated in this signature.

Errors

This function will return any I/O error reported while formatting.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Write.

The returned adaptor also implements Write and will simply borrow this current writer.

Implementations on Foreign Types

impl Write for &mut [u8]

Write is implemented for &mut [u8] by copying into the slice, overwriting its data.

Note that writing updates the slice to point to the yet unwritten part. The slice will be empty when it has been completely overwritten.

fn write(&mut self, data: &[u8]) -> Result<usize>

fn write_all(&mut self, data: &[u8]) -> Result<()>

fn flush(&mut self) -> Result<()>

impl<W: Write + ?Sized> Write for &mut W

fn write(&mut self, buf: &[u8]) -> Result<usize>

fn flush(&mut self) -> Result<()>

fn write_all(&mut self, buf: &[u8]) -> Result<()>

fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<()>

Implementors

impl Write for Cursor<&mut [u8]>

impl Write for Sink