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#![cfg_attr(not(feature = "std"), no_std)]
#![cfg_attr(docsrs, feature(doc_cfg))]
#![warn(missing_docs)]
#![doc = include_str!("../README.md")]
use core::fmt;
// needed to prevent defmt macros from breaking, since they emit code that does `defmt::blahblah`.
#[cfg(feature = "defmt-03")]
use defmt_03 as defmt;
#[cfg(feature = "alloc")]
extern crate alloc;
mod impls;
/// Enumeration of possible methods to seek within an I/O object.
///
/// This is the `embedded-io` equivalent of [`std::io::SeekFrom`].
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
pub enum SeekFrom {
/// Sets the offset to the provided number of bytes.
Start(u64),
/// Sets the offset to the size of this object plus the specified number of bytes.
End(i64),
/// Sets the offset to the current position plus the specified number of bytes.
Current(i64),
}
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
impl From<SeekFrom> for std::io::SeekFrom {
fn from(pos: SeekFrom) -> Self {
match pos {
SeekFrom::Start(n) => std::io::SeekFrom::Start(n),
SeekFrom::End(n) => std::io::SeekFrom::End(n),
SeekFrom::Current(n) => std::io::SeekFrom::Current(n),
}
}
}
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
impl From<std::io::SeekFrom> for SeekFrom {
fn from(pos: std::io::SeekFrom) -> SeekFrom {
match pos {
std::io::SeekFrom::Start(n) => SeekFrom::Start(n),
std::io::SeekFrom::End(n) => SeekFrom::End(n),
std::io::SeekFrom::Current(n) => SeekFrom::Current(n),
}
}
}
/// Possible kinds of errors.
///
/// This list is intended to grow over time and it is not recommended to
/// exhaustively match against it. In application code, use `match` for the `ErrorKind`
/// values you are expecting; use `_` to match "all other errors".
///
/// This is the `embedded-io` equivalent of [`std::io::ErrorKind`], except with the following changes:
///
/// - `WouldBlock` is removed, since `embedded-io` traits are always blocking. See the [crate-level documentation](crate) for details.
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
#[non_exhaustive]
pub enum ErrorKind {
/// Unspecified error kind.
Other,
/// An entity was not found, often a file.
NotFound,
/// The operation lacked the necessary privileges to complete.
PermissionDenied,
/// The connection was refused by the remote server.
ConnectionRefused,
/// The connection was reset by the remote server.
ConnectionReset,
/// The connection was aborted (terminated) by the remote server.
ConnectionAborted,
/// The network operation failed because it was not connected yet.
NotConnected,
/// A socket address could not be bound because the address is already in
/// use elsewhere.
AddrInUse,
/// A nonexistent interface was requested or the requested address was not
/// local.
AddrNotAvailable,
/// The operation failed because a pipe was closed.
BrokenPipe,
/// An entity already exists, often a file.
AlreadyExists,
/// A parameter was incorrect.
InvalidInput,
/// Data not valid for the operation were encountered.
///
/// Unlike [`InvalidInput`], this typically means that the operation
/// parameters were valid, however the error was caused by malformed
/// input data.
///
/// For example, a function that reads a file into a string will error with
/// `InvalidData` if the file's contents are not valid UTF-8.
///
/// [`InvalidInput`]: ErrorKind::InvalidInput
InvalidData,
/// The I/O operation's timeout expired, causing it to be canceled.
TimedOut,
/// This operation was interrupted.
///
/// Interrupted operations can typically be retried.
Interrupted,
/// This operation is unsupported on this platform.
///
/// This means that the operation can never succeed.
Unsupported,
/// An operation could not be completed, because it failed
/// to allocate enough memory.
OutOfMemory,
/// An attempted write could not write any data.
WriteZero,
}
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
impl From<ErrorKind> for std::io::ErrorKind {
fn from(value: ErrorKind) -> Self {
match value {
ErrorKind::NotFound => std::io::ErrorKind::NotFound,
ErrorKind::PermissionDenied => std::io::ErrorKind::PermissionDenied,
ErrorKind::ConnectionRefused => std::io::ErrorKind::ConnectionRefused,
ErrorKind::ConnectionReset => std::io::ErrorKind::ConnectionReset,
ErrorKind::ConnectionAborted => std::io::ErrorKind::ConnectionAborted,
ErrorKind::NotConnected => std::io::ErrorKind::NotConnected,
ErrorKind::AddrInUse => std::io::ErrorKind::AddrInUse,
ErrorKind::AddrNotAvailable => std::io::ErrorKind::AddrNotAvailable,
ErrorKind::BrokenPipe => std::io::ErrorKind::BrokenPipe,
ErrorKind::AlreadyExists => std::io::ErrorKind::AlreadyExists,
ErrorKind::InvalidInput => std::io::ErrorKind::InvalidInput,
ErrorKind::InvalidData => std::io::ErrorKind::InvalidData,
ErrorKind::TimedOut => std::io::ErrorKind::TimedOut,
ErrorKind::Interrupted => std::io::ErrorKind::Interrupted,
ErrorKind::Unsupported => std::io::ErrorKind::Unsupported,
ErrorKind::OutOfMemory => std::io::ErrorKind::OutOfMemory,
_ => std::io::ErrorKind::Other,
}
}
}
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
impl From<std::io::ErrorKind> for ErrorKind {
fn from(value: std::io::ErrorKind) -> Self {
match value {
std::io::ErrorKind::NotFound => ErrorKind::NotFound,
std::io::ErrorKind::PermissionDenied => ErrorKind::PermissionDenied,
std::io::ErrorKind::ConnectionRefused => ErrorKind::ConnectionRefused,
std::io::ErrorKind::ConnectionReset => ErrorKind::ConnectionReset,
std::io::ErrorKind::ConnectionAborted => ErrorKind::ConnectionAborted,
std::io::ErrorKind::NotConnected => ErrorKind::NotConnected,
std::io::ErrorKind::AddrInUse => ErrorKind::AddrInUse,
std::io::ErrorKind::AddrNotAvailable => ErrorKind::AddrNotAvailable,
std::io::ErrorKind::BrokenPipe => ErrorKind::BrokenPipe,
std::io::ErrorKind::AlreadyExists => ErrorKind::AlreadyExists,
std::io::ErrorKind::InvalidInput => ErrorKind::InvalidInput,
std::io::ErrorKind::InvalidData => ErrorKind::InvalidData,
std::io::ErrorKind::TimedOut => ErrorKind::TimedOut,
std::io::ErrorKind::Interrupted => ErrorKind::Interrupted,
std::io::ErrorKind::Unsupported => ErrorKind::Unsupported,
std::io::ErrorKind::OutOfMemory => ErrorKind::OutOfMemory,
_ => ErrorKind::Other,
}
}
}
/// Error trait.
///
/// This trait allows generic code to do limited inspecting of errors,
/// to react differently to different kinds.
pub trait Error: fmt::Debug {
/// Get the kind of this error.
fn kind(&self) -> ErrorKind;
}
impl Error for core::convert::Infallible {
fn kind(&self) -> ErrorKind {
match *self {}
}
}
impl Error for ErrorKind {
fn kind(&self) -> ErrorKind {
*self
}
}
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
impl Error for std::io::Error {
fn kind(&self) -> ErrorKind {
self.kind().into()
}
}
/// Base trait for all IO traits, defining the error type.
///
/// All IO operations of all traits return the error defined in this trait.
///
/// Having a shared trait instead of having every trait define its own
/// `Error` associated type enforces all impls on the same type use the same error.
/// This is very convenient when writing generic code, it means you have to
/// handle a single error type `T::Error`, instead of `<T as Read>::Error` and `<T as Write>::Error`
/// which might be different types.
pub trait ErrorType {
/// Error type of all the IO operations on this type.
type Error: Error;
}
impl<T: ?Sized + ErrorType> ErrorType for &mut T {
type Error = T::Error;
}
/// Error returned by [`Read::read_exact`]
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
pub enum ReadExactError<E> {
/// An EOF error was encountered before reading the exact amount of requested bytes.
UnexpectedEof,
/// Error returned by the inner Read.
Other(E),
}
impl<E> From<E> for ReadExactError<E> {
fn from(err: E) -> Self {
Self::Other(err)
}
}
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
impl From<ReadExactError<std::io::Error>> for std::io::Error {
fn from(err: ReadExactError<std::io::Error>) -> Self {
match err {
ReadExactError::UnexpectedEof => std::io::Error::new(
std::io::ErrorKind::UnexpectedEof,
"UnexpectedEof".to_owned(),
),
ReadExactError::Other(e) => std::io::Error::new(e.kind(), format!("{e:?}")),
}
}
}
impl<E: fmt::Debug> fmt::Display for ReadExactError<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{self:?}")
}
}
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
impl<E: fmt::Debug> std::error::Error for ReadExactError<E> {}
/// Errors that could be returned by `Write` on `&mut [u8]`.
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
#[non_exhaustive]
pub enum SliceWriteError {
/// The target slice was full and so could not receive any new data.
Full,
}
/// Error returned by [`Write::write_fmt`]
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
pub enum WriteFmtError<E> {
/// An error was encountered while formatting.
FmtError,
/// Error returned by the inner Write.
Other(E),
}
impl<E> From<E> for WriteFmtError<E> {
fn from(err: E) -> Self {
Self::Other(err)
}
}
impl<E: fmt::Debug> fmt::Display for WriteFmtError<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{self:?}")
}
}
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
impl<E: fmt::Debug> std::error::Error for WriteFmtError<E> {}
/// Blocking reader.
///
/// This trait is the `embedded-io` equivalent of [`std::io::Read`].
pub trait Read: ErrorType {
/// Read some bytes from this source into the specified buffer, returning how many bytes were read.
///
/// If no bytes are currently available to read, this function blocks until at least one byte is available.
///
/// If bytes are available, a non-zero amount of bytes is read to the beginning of `buf`, and the amount
/// is returned. It is not guaranteed that *all* available bytes are returned, it is possible for the
/// implementation to read an amount of bytes less than `buf.len()` while there are more bytes immediately
/// available.
///
/// If the reader is at end-of-file (EOF), `Ok(0)` is returned. There is no guarantee that a reader at EOF
/// will always be so in the future, for example a reader can stop being at EOF if another process appends
/// more bytes to the underlying file.
///
/// If `buf.len() == 0`, `read` returns without blocking, with either `Ok(0)` or an error.
/// The `Ok(0)` doesn't indicate EOF, unlike when called with a non-empty buffer.
fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error>;
/// Read the exact number of bytes required to fill `buf`.
///
/// This function calls `read()` in a loop until exactly `buf.len()` bytes have
/// been read, blocking if needed.
///
/// If you are using [`ReadReady`] to avoid blocking, you should not use this function.
/// `ReadReady::read_ready()` returning true only guarantees the first call to `read()` will
/// not block, so this function may still block in subsequent calls.
fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<(), ReadExactError<Self::Error>> {
while !buf.is_empty() {
match self.read(buf) {
Ok(0) => break,
Ok(n) => buf = &mut buf[n..],
Err(e) => return Err(ReadExactError::Other(e)),
}
}
if buf.is_empty() {
Ok(())
} else {
Err(ReadExactError::UnexpectedEof)
}
}
}
/// Blocking buffered reader.
///
/// This trait is the `embedded-io` equivalent of [`std::io::BufRead`].
pub trait BufRead: ErrorType {
/// Return the contents of the internal buffer, filling it with more data from the inner reader if it is empty.
///
/// If no bytes are currently available to read, this function blocks until at least one byte is available.
///
/// If the reader is at end-of-file (EOF), an empty slice is returned. There is no guarantee that a reader at EOF
/// will always be so in the future, for example a reader can stop being at EOF if another process appends
/// more bytes to the underlying file.
fn fill_buf(&mut self) -> Result<&[u8], Self::Error>;
/// Tell this buffer that `amt` bytes have been consumed from the buffer, so they should no longer be returned in calls to `fill_buf`.
fn consume(&mut self, amt: usize);
}
/// Blocking writer.
///
/// This trait is the `embedded-io` equivalent of [`std::io::Write`].
pub trait Write: ErrorType {
/// Write a buffer into this writer, returning how many bytes were written.
///
/// If the writer is not currently ready to accept more bytes (for example, its buffer is full),
/// this function blocks until it is ready to accept least one byte.
///
/// If it's ready to accept bytes, a non-zero amount of bytes is written from the beginning of `buf`, and the amount
/// is returned. It is not guaranteed that *all* available buffer space is filled, i.e. it is possible for the
/// implementation to write an amount of bytes less than `buf.len()` while the writer continues to be
/// ready to accept more bytes immediately.
///
/// Implementations must not return `Ok(0)` unless `buf` is empty. Situations where the
/// writer is not able to accept more bytes must instead be indicated with an error,
/// where the `ErrorKind` is `WriteZero`.
///
/// If `buf` is empty, `write` returns without blocking, with either `Ok(0)` or an error.
/// `Ok(0)` doesn't indicate an error.
fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error>;
/// Flush this output stream, blocking until all intermediately buffered contents reach their destination.
fn flush(&mut self) -> Result<(), Self::Error>;
/// Write an entire buffer into this writer.
///
/// This function calls `write()` in a loop until exactly `buf.len()` bytes have
/// been written, blocking if needed.
///
/// If you are using [`WriteReady`] to avoid blocking, you should not use this function.
/// `WriteReady::write_ready()` returning true only guarantees the first call to `write()` will
/// not block, so this function may still block in subsequent calls.
///
/// This function will panic if `write()` returns `Ok(0)`.
fn write_all(&mut self, mut buf: &[u8]) -> Result<(), Self::Error> {
while !buf.is_empty() {
match self.write(buf) {
Ok(0) => panic!("write() returned Ok(0)"),
Ok(n) => buf = &buf[n..],
Err(e) => return Err(e),
}
}
Ok(())
}
/// Write a formatted string into this writer, returning any error encountered.
///
/// This function calls `write()` in a loop until the entire formatted string has
/// been written, blocking if needed.
///
/// If you are using [`WriteReady`] to avoid blocking, you should not use this function.
/// `WriteReady::write_ready()` returning true only guarantees the first call to `write()` will
/// not block, so this function may still block in subsequent calls.
///
/// Unlike [`Write::write`], the number of bytes written is not returned. However, in the case of
/// writing to an `&mut [u8]` its possible to calculate the number of bytes written by subtracting
/// the length of the slice after the write, from the initial length of the slice.
///
/// ```rust
/// # use embedded_io::Write;
/// let mut buf: &mut [u8] = &mut [0u8; 256];
/// let start = buf.len();
/// let len = write!(buf, "{}", "Test").and_then(|_| Ok(start - buf.len()));
/// ```
fn write_fmt(&mut self, fmt: fmt::Arguments<'_>) -> Result<(), WriteFmtError<Self::Error>> {
// Create a shim which translates a Write to a fmt::Write and saves
// off I/O errors. instead of discarding them
struct Adapter<'a, T: Write + ?Sized + 'a> {
inner: &'a mut T,
error: Result<(), T::Error>,
}
impl<T: Write + ?Sized> fmt::Write for Adapter<'_, T> {
fn write_str(&mut self, s: &str) -> fmt::Result {
match self.inner.write_all(s.as_bytes()) {
Ok(()) => Ok(()),
Err(e) => {
self.error = Err(e);
Err(fmt::Error)
}
}
}
}
let mut output = Adapter {
inner: self,
error: Ok(()),
};
match fmt::write(&mut output, fmt) {
Ok(()) => Ok(()),
Err(..) => match output.error {
// check if the error came from the underlying `Write` or not
Err(e) => Err(WriteFmtError::Other(e)),
Ok(()) => Err(WriteFmtError::FmtError),
},
}
}
}
/// Blocking seek within streams.
///
/// This trait is the `embedded-io` equivalent of [`std::io::Seek`].
pub trait Seek: ErrorType {
/// Seek to an offset, in bytes, in a stream.
fn seek(&mut self, pos: SeekFrom) -> Result<u64, Self::Error>;
/// Rewind to the beginning of a stream.
fn rewind(&mut self) -> Result<(), Self::Error> {
self.seek(SeekFrom::Start(0))?;
Ok(())
}
/// Returns the current seek position from the start of the stream.
fn stream_position(&mut self) -> Result<u64, Self::Error> {
self.seek(SeekFrom::Current(0))
}
}
/// Get whether a reader is ready.
///
/// This allows using a [`Read`] or [`BufRead`] in a nonblocking fashion, i.e. trying to read
/// only when it is ready.
pub trait ReadReady: ErrorType {
/// Get whether the reader is ready for immediately reading.
///
/// This usually means that there is either some bytes have been received and are buffered and ready to be read,
/// or that the reader is at EOF.
///
/// If this returns `true`, it's guaranteed that the next call to [`Read::read`] or [`BufRead::fill_buf`] will not block.
fn read_ready(&mut self) -> Result<bool, Self::Error>;
}
/// Get whether a writer is ready.
///
/// This allows using a [`Write`] in a nonblocking fashion, i.e. trying to write
/// only when it is ready.
pub trait WriteReady: ErrorType {
/// Get whether the writer is ready for immediately writing.
///
/// This usually means that there is free space in the internal transmit buffer.
///
/// If this returns `true`, it's guaranteed that the next call to [`Write::write`] will not block.
fn write_ready(&mut self) -> Result<bool, Self::Error>;
}
impl<T: ?Sized + Read> Read for &mut T {
#[inline]
fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
T::read(self, buf)
}
}
impl<T: ?Sized + BufRead> BufRead for &mut T {
fn fill_buf(&mut self) -> Result<&[u8], Self::Error> {
T::fill_buf(self)
}
fn consume(&mut self, amt: usize) {
T::consume(self, amt);
}
}
impl<T: ?Sized + Write> Write for &mut T {
#[inline]
fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
T::write(self, buf)
}
#[inline]
fn flush(&mut self) -> Result<(), Self::Error> {
T::flush(self)
}
}
impl<T: ?Sized + Seek> Seek for &mut T {
#[inline]
fn seek(&mut self, pos: SeekFrom) -> Result<u64, Self::Error> {
T::seek(self, pos)
}
}
impl<T: ?Sized + ReadReady> ReadReady for &mut T {
#[inline]
fn read_ready(&mut self) -> Result<bool, Self::Error> {
T::read_ready(self)
}
}
impl<T: ?Sized + WriteReady> WriteReady for &mut T {
#[inline]
fn write_ready(&mut self) -> Result<bool, Self::Error> {
T::write_ready(self)
}
}