Strip std::io down

.gitignore

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+/target
+
+
+#Added by cargo
+#
+#already existing elements were commented out
+
+#/target
+Cargo.lock

Cargo.toml

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+[package]
+name = "bare-io"
+version = "0.1.0"
+authors = ["Brendan Molloy <brendan@bbqsrc.net>"]
+description = "The bare essentials of std::io for use in no_std. No alloc!"
+license = "Apache-2.0 OR MIT"
+edition = "2018"
+
+[dependencies]

src/error.rs

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+use core::{convert::From, fmt, result};
+
+/// A specialized [`Result`] type for I/O operations.
+///
+/// This type is broadly used across [`std::io`] for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out [`io::Error`] directly and
+/// is otherwise a direct mapping to [`Result`].
+///
+/// While usual Rust style is to import types directly, aliases of [`Result`]
+/// often are not, to make it easier to distinguish between them. [`Result`] is
+/// generally assumed to be [`std::result::Result`][`Result`], and so users of this alias
+/// will generally use `io::Result` instead of shadowing the [prelude]'s import
+/// of [`std::result::Result`][`Result`].
+///
+/// [`std::io`]: crate::io
+/// [`io::Error`]: Error
+/// [`Result`]: crate::result::Result
+/// [prelude]: crate::prelude
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     io::stdin().read_line(&mut buffer)?;
+///
+///     Ok(buffer)
+/// }
+/// ```
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the [`Read`], [`Write`], [`Seek`], and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// [`ErrorKind`].
+///
+/// [`Read`]: crate::io::Read
+/// [`Write`]: crate::io::Write
+/// [`Seek`]: crate::io::Seek
+pub struct Error {
+    repr: Repr,
+}
+
+impl fmt::Debug for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Debug::fmt(&self.repr, f)
+    }
+}
+
+enum Repr {
+    Simple(ErrorKind),
+    Custom(Custom),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: &'static str,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+///
+/// It is used with the [`io::Error`] type.
+///
+/// [`io::Error`]: Error
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+// #[allow(deprecated)]
+#[non_exhaustive]
+pub enum ErrorKind {
+    /// 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,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    WouldBlock,
+    /// 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,
+    /// An error returned when an operation could not be completed because a
+    /// call to [`write`] returned [`Ok(0)`].
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    ///
+    /// [`write`]: crate::io::Write::write
+    /// [`Ok(0)`]: Ok
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    Interrupted,
+    /// Any I/O error not part of this list.
+    ///
+    /// Errors that are `Other` now may move to a different or a new
+    /// [`ErrorKind`] variant in the future. It is not recommended to match
+    /// an error against `Other` and to expect any additional characteristics,
+    /// e.g., a specific [`Error::raw_os_error`] return value.
+    Other,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    UnexpectedEof,
+}
+
+impl ErrorKind {
+    pub(crate) fn as_str(&self) -> &'static str {
+        match *self {
+            ErrorKind::NotFound => "entity not found",
+            ErrorKind::PermissionDenied => "permission denied",
+            ErrorKind::ConnectionRefused => "connection refused",
+            ErrorKind::ConnectionReset => "connection reset",
+            ErrorKind::ConnectionAborted => "connection aborted",
+            ErrorKind::NotConnected => "not connected",
+            ErrorKind::AddrInUse => "address in use",
+            ErrorKind::AddrNotAvailable => "address not available",
+            ErrorKind::BrokenPipe => "broken pipe",
+            ErrorKind::AlreadyExists => "entity already exists",
+            ErrorKind::WouldBlock => "operation would block",
+            ErrorKind::InvalidInput => "invalid input parameter",
+            ErrorKind::InvalidData => "invalid data",
+            ErrorKind::TimedOut => "timed out",
+            ErrorKind::WriteZero => "write zero",
+            ErrorKind::Interrupted => "operation interrupted",
+            ErrorKind::Other => "other os error",
+            ErrorKind::UnexpectedEof => "unexpected end of file",
+        }
+    }
+}
+
+/// Intended for use for errors not exposed to the user, where allocating onto
+/// the heap (for normal construction via Error::new) is too costly.
+impl From<ErrorKind> for Error {
+    /// Converts an [`ErrorKind`] into an [`Error`].
+    ///
+    /// This conversion allocates a new error with a simple representation of error kind.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// let not_found = ErrorKind::NotFound;
+    /// let error = Error::from(not_found);
+    /// assert_eq!("entity not found", format!("{}", error));
+    /// ```
+    #[inline]
+    fn from(kind: ErrorKind) -> Error {
+        Error { repr: Repr::Simple(kind) }
+    }
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this [`Error`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    pub fn new(kind: ErrorKind, error: &'static str) -> Error {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: &'static str) -> Error {
+        Error { repr: Repr::Custom(Custom { kind, error }) }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this [`Error`] was constructed via [`new`] then this function will
+    /// return [`Some`], otherwise it will return [`None`].
+    ///
+    /// [`new`]: Error::new
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {:?}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    pub fn get_ref(&self) -> Option<&&'static str> {
+        match self.repr {
+            Repr::Simple(..) => None,
+            Repr::Custom(ref c) => Some(&c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this [`Error`] was constructed via [`new`] then this function will
+    /// return [`Some`], otherwise it will return [`None`].
+    ///
+    /// [`new`]: Error::new
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     if let Some(inner_err) = err.into_inner() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    pub fn into_inner(self) -> Option<&'static str> {
+        match self.repr {
+            Repr::Simple(..) => None,
+            Repr::Custom(c) => Some(c.error),
+        }
+    }
+
+    /// Returns the corresponding [`ErrorKind`] for this error.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     println!("{:?}", err.kind());
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "Other".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "AddrInUse".
+    ///     print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
+    /// }
+    /// ```
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Custom(ref c) => c.kind,
+            Repr::Simple(kind) => kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match *self {
+            Repr::Custom(ref c) => fmt::Debug::fmt(&c, fmt),
+            Repr::Simple(kind) => fmt.debug_tuple("Kind").field(&kind).finish(),
+        }
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.repr {
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+            Repr::Simple(kind) => write!(fmt, "{}", kind.as_str()),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync + Send>() {}
+    _is_sync_send::<Error>();
+}