RedBear-OS/src/io/error.rs

// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use alloc::{boxed::Box, string::String};
use core::{fmt, result, str};

use crate::platform::types::c_int;

/// A specialized [`Result`](../result/enum.Result.html) 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`]: ../io/index.html
/// [`io::Error`]: ../io/struct.Error.html
/// [`Result`]: ../result/enum.Result.html
///
/// # 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`]: ../io/trait.Read.html
/// [`Write`]: ../io/trait.Write.html
/// [`Seek`]: ../io/trait.Seek.html
/// [`ErrorKind`]: enum.ErrorKind.html
pub struct Error {
    repr: Repr,
}

// TODO?
impl Error {
    pub fn raw_os_error(&self) -> Option<c_int> {
        if let Repr::Os(os) = self.repr {
            Some(os)
        } else {
            None
        }
    }
}

impl fmt::Debug for Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        fmt::Debug::fmt(&self.repr, f)
    }
}

impl fmt::Display for Error {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        match self.repr {
            Repr::Os(code) => {
                write!(fmt, "os error {}", code)
            }
            Repr::Custom(ref c) => c.error.fmt(fmt),
            Repr::Simple(kind) => write!(fmt, "{}", kind.as_str()),
        }
    }
}

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<E>(kind: ErrorKind, error: E) -> Error
    where
        E: Into<String>,
    {
        Self::_new(kind, error.into())
    }

    fn _new(kind: ErrorKind, error: String) -> Error {
        Error {
            repr: Repr::Custom(Box::new(Custom { kind, error })),
        }
    }

    /// Creates a new instance of an `Error` from a particular OS error code.
    ///
    /// # Examples
    ///
    /// On Linux:
    ///
    /// ```
    /// # if cfg!(target_os = "linux") {
    /// use std::io;
    ///
    /// let error = io::Error::from_raw_os_error(22);
    /// assert_eq!(error.kind(), io::ErrorKind::InvalidInput);
    /// # }
    /// ```
    ///
    /// On Windows:
    ///
    /// ```
    /// # if cfg!(windows) {
    /// use std::io;
    ///
    /// let error = io::Error::from_raw_os_error(10022);
    /// assert_eq!(error.kind(), io::ErrorKind::InvalidInput);
    /// # }
    /// ```
    pub fn from_raw_os_error(code: i32) -> Error {
        Error {
            repr: Repr::Os(code),
        }
    }

    /// 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 "No inner error".
    ///     print_error(Error::last_os_error());
    ///     // Will print "Inner error: ...".
    ///     print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
    /// }
    /// ```
    pub fn kind(&self) -> ErrorKind {
        match self.repr {
            Repr::Os(_code) => ErrorKind::Other,
            Repr::Custom(ref c) => c.kind,
            Repr::Simple(kind) => kind,
        }
    }

    pub fn last_os_error() -> Error {
        let errno = crate::platform::ERRNO.get();
        Error::from_raw_os_error(errno)
    }
}

enum Repr {
    Os(i32),
    Simple(ErrorKind),
    Custom(Box<Custom>),
}

impl fmt::Debug for Repr {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            Repr::Os(code) => fmt.debug_struct("Os").field("code", &code).finish(),
            Repr::Custom(ref c) => fmt::Debug::fmt(&c, fmt),
            Repr::Simple(kind) => fmt.debug_tuple("Kind").field(&kind).finish(),
        }
    }
}

#[derive(Debug)]
struct Custom {
    kind: ErrorKind,
    error: String,
}

/// 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`]: struct.Error.html
#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
#[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`]: #variant.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`]: ../../std/io/trait.Write.html#tymethod.write
    /// [`Ok(0)`]: ../../std/io/type.Result.html
    WriteZero,
    /// This operation was interrupted.
    ///
    /// Interrupted operations can typically be retried.
    Interrupted,
    /// Any I/O error not part of this list.
    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 {
    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",
        }
    }
}