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Diffstat (limited to 'src/libstd/io/stdio.rs')
| -rw-r--r-- | src/libstd/io/stdio.rs | 1064 |
1 files changed, 0 insertions, 1064 deletions
diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs deleted file mode 100644 index 156f555be02..00000000000 --- a/src/libstd/io/stdio.rs +++ /dev/null @@ -1,1064 +0,0 @@ -#![cfg_attr(test, allow(unused))] - -use crate::io::prelude::*; - -use crate::cell::RefCell; -use crate::fmt; -use crate::io::lazy::Lazy; -use crate::io::{self, BufReader, Initializer, IoSlice, IoSliceMut, LineWriter}; -use crate::sync::{Arc, Mutex, MutexGuard, Once}; -use crate::sys::stdio; -use crate::sys_common::remutex::{ReentrantMutex, ReentrantMutexGuard}; -use crate::thread::LocalKey; - -thread_local! { - /// Stdout used by print! and println! macros - static LOCAL_STDOUT: RefCell<Option<Box<dyn Write + Send>>> = { - RefCell::new(None) - } -} - -thread_local! { - /// Stderr used by eprint! and eprintln! macros, and panics - static LOCAL_STDERR: RefCell<Option<Box<dyn Write + Send>>> = { - RefCell::new(None) - } -} - -/// A handle to a raw instance of the standard input stream of this process. -/// -/// This handle is not synchronized or buffered in any fashion. Constructed via -/// the `std::io::stdio::stdin_raw` function. -struct StdinRaw(stdio::Stdin); - -/// A handle to a raw instance of the standard output stream of this process. -/// -/// This handle is not synchronized or buffered in any fashion. Constructed via -/// the `std::io::stdio::stdout_raw` function. -struct StdoutRaw(stdio::Stdout); - -/// A handle to a raw instance of the standard output stream of this process. -/// -/// This handle is not synchronized or buffered in any fashion. Constructed via -/// the `std::io::stdio::stderr_raw` function. -struct StderrRaw(stdio::Stderr); - -/// Constructs a new raw handle to the standard input of this process. -/// -/// The returned handle does not interact with any other handles created nor -/// handles returned by `std::io::stdin`. Data buffered by the `std::io::stdin` -/// handles is **not** available to raw handles returned from this function. -/// -/// The returned handle has no external synchronization or buffering. -fn stdin_raw() -> io::Result<StdinRaw> { - stdio::Stdin::new().map(StdinRaw) -} - -/// Constructs a new raw handle to the standard output stream of this process. -/// -/// The returned handle does not interact with any other handles created nor -/// handles returned by `std::io::stdout`. Note that data is buffered by the -/// `std::io::stdout` handles so writes which happen via this raw handle may -/// appear before previous writes. -/// -/// The returned handle has no external synchronization or buffering layered on -/// top. -fn stdout_raw() -> io::Result<StdoutRaw> { - stdio::Stdout::new().map(StdoutRaw) -} - -/// Constructs a new raw handle to the standard error stream of this process. -/// -/// The returned handle does not interact with any other handles created nor -/// handles returned by `std::io::stderr`. -/// -/// The returned handle has no external synchronization or buffering layered on -/// top. -fn stderr_raw() -> io::Result<StderrRaw> { - stdio::Stderr::new().map(StderrRaw) -} - -impl Read for StdinRaw { - fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { - self.0.read(buf) - } - - fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> { - self.0.read_vectored(bufs) - } - - #[inline] - fn is_read_vectored(&self) -> bool { - self.0.is_read_vectored() - } - - #[inline] - unsafe fn initializer(&self) -> Initializer { - Initializer::nop() - } - - fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> { - self.0.read_to_end(buf) - } - - fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> { - self.0.read_to_string(buf) - } - - fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> { - self.0.read_exact(buf) - } -} - -impl Write for StdoutRaw { - fn write(&mut self, buf: &[u8]) -> io::Result<usize> { - self.0.write(buf) - } - - fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { - self.0.write_vectored(bufs) - } - - #[inline] - fn is_write_vectored(&self) -> bool { - self.0.is_write_vectored() - } - - fn flush(&mut self) -> io::Result<()> { - self.0.flush() - } - - fn write_all(&mut self, buf: &[u8]) -> io::Result<()> { - self.0.write_all(buf) - } - - fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> io::Result<()> { - self.0.write_all_vectored(bufs) - } - - fn write_fmt(&mut self, fmt: fmt::Arguments<'_>) -> io::Result<()> { - self.0.write_fmt(fmt) - } -} - -impl Write for StderrRaw { - fn write(&mut self, buf: &[u8]) -> io::Result<usize> { - self.0.write(buf) - } - - fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { - self.0.write_vectored(bufs) - } - - #[inline] - fn is_write_vectored(&self) -> bool { - self.0.is_write_vectored() - } - - fn flush(&mut self) -> io::Result<()> { - self.0.flush() - } - - fn write_all(&mut self, buf: &[u8]) -> io::Result<()> { - self.0.write_all(buf) - } - - fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> io::Result<()> { - self.0.write_all_vectored(bufs) - } - - fn write_fmt(&mut self, fmt: fmt::Arguments<'_>) -> io::Result<()> { - self.0.write_fmt(fmt) - } -} - -enum Maybe<T> { - Real(T), - Fake, -} - -impl<W: io::Write> io::Write for Maybe<W> { - fn write(&mut self, buf: &[u8]) -> io::Result<usize> { - match *self { - Maybe::Real(ref mut w) => handle_ebadf(w.write(buf), buf.len()), - Maybe::Fake => Ok(buf.len()), - } - } - - fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { - let total = bufs.iter().map(|b| b.len()).sum(); - match self { - Maybe::Real(w) => handle_ebadf(w.write_vectored(bufs), total), - Maybe::Fake => Ok(total), - } - } - - #[inline] - fn is_write_vectored(&self) -> bool { - match self { - Maybe::Real(w) => w.is_write_vectored(), - Maybe::Fake => true, - } - } - - fn flush(&mut self) -> io::Result<()> { - match *self { - Maybe::Real(ref mut w) => handle_ebadf(w.flush(), ()), - Maybe::Fake => Ok(()), - } - } -} - -impl<R: io::Read> io::Read for Maybe<R> { - fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { - match *self { - Maybe::Real(ref mut r) => handle_ebadf(r.read(buf), 0), - Maybe::Fake => Ok(0), - } - } - - fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> { - match self { - Maybe::Real(r) => handle_ebadf(r.read_vectored(bufs), 0), - Maybe::Fake => Ok(0), - } - } - - #[inline] - fn is_read_vectored(&self) -> bool { - match self { - Maybe::Real(w) => w.is_read_vectored(), - Maybe::Fake => true, - } - } -} - -fn handle_ebadf<T>(r: io::Result<T>, default: T) -> io::Result<T> { - match r { - Err(ref e) if stdio::is_ebadf(e) => Ok(default), - r => r, - } -} - -/// A handle to the standard input stream of a process. -/// -/// Each handle is a shared reference to a global buffer of input data to this -/// process. A handle can be `lock`'d to gain full access to [`BufRead`] methods -/// (e.g., `.lines()`). Reads to this handle are otherwise locked with respect -/// to other reads. -/// -/// This handle implements the `Read` trait, but beware that concurrent reads -/// of `Stdin` must be executed with care. -/// -/// Created by the [`io::stdin`] method. -/// -/// [`io::stdin`]: fn.stdin.html -/// [`BufRead`]: trait.BufRead.html -/// -/// ### Note: Windows Portability Consideration -/// -/// When operating in a console, the Windows implementation of this stream does not support -/// non-UTF-8 byte sequences. Attempting to read bytes that are not valid UTF-8 will return -/// an error. -/// -/// # Examples -/// -/// ```no_run -/// use std::io::{self, Read}; -/// -/// fn main() -> io::Result<()> { -/// let mut buffer = String::new(); -/// let mut stdin = io::stdin(); // We get `Stdin` here. -/// stdin.read_to_string(&mut buffer)?; -/// Ok(()) -/// } -/// ``` -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Stdin { - inner: Arc<Mutex<BufReader<Maybe<StdinRaw>>>>, -} - -/// A locked reference to the `Stdin` handle. -/// -/// This handle implements both the [`Read`] and [`BufRead`] traits, and -/// is constructed via the [`Stdin::lock`] method. -/// -/// [`Read`]: trait.Read.html -/// [`BufRead`]: trait.BufRead.html -/// [`Stdin::lock`]: struct.Stdin.html#method.lock -/// -/// ### Note: Windows Portability Consideration -/// -/// When operating in a console, the Windows implementation of this stream does not support -/// non-UTF-8 byte sequences. Attempting to read bytes that are not valid UTF-8 will return -/// an error. -/// -/// # Examples -/// -/// ```no_run -/// use std::io::{self, Read}; -/// -/// fn main() -> io::Result<()> { -/// let mut buffer = String::new(); -/// let stdin = io::stdin(); // We get `Stdin` here. -/// { -/// let mut stdin_lock = stdin.lock(); // We get `StdinLock` here. -/// stdin_lock.read_to_string(&mut buffer)?; -/// } // `StdinLock` is dropped here. -/// Ok(()) -/// } -/// ``` -#[stable(feature = "rust1", since = "1.0.0")] -pub struct StdinLock<'a> { - inner: MutexGuard<'a, BufReader<Maybe<StdinRaw>>>, -} - -/// Constructs a new handle to the standard input of the current process. -/// -/// Each handle returned is a reference to a shared global buffer whose access -/// is synchronized via a mutex. If you need more explicit control over -/// locking, see the [`Stdin::lock`] method. -/// -/// [`Stdin::lock`]: struct.Stdin.html#method.lock -/// -/// ### Note: Windows Portability Consideration -/// When operating in a console, the Windows implementation of this stream does not support -/// non-UTF-8 byte sequences. Attempting to read bytes that are not valid UTF-8 will return -/// an error. -/// -/// # Examples -/// -/// Using implicit synchronization: -/// -/// ```no_run -/// use std::io::{self, Read}; -/// -/// fn main() -> io::Result<()> { -/// let mut buffer = String::new(); -/// io::stdin().read_to_string(&mut buffer)?; -/// Ok(()) -/// } -/// ``` -/// -/// Using explicit synchronization: -/// -/// ```no_run -/// use std::io::{self, Read}; -/// -/// fn main() -> io::Result<()> { -/// let mut buffer = String::new(); -/// let stdin = io::stdin(); -/// let mut handle = stdin.lock(); -/// -/// handle.read_to_string(&mut buffer)?; -/// Ok(()) -/// } -/// ``` -#[stable(feature = "rust1", since = "1.0.0")] -pub fn stdin() -> Stdin { - static INSTANCE: Lazy<Mutex<BufReader<Maybe<StdinRaw>>>> = Lazy::new(); - return Stdin { - inner: unsafe { INSTANCE.get(stdin_init).expect("cannot access stdin during shutdown") }, - }; - - fn stdin_init() -> Arc<Mutex<BufReader<Maybe<StdinRaw>>>> { - // This must not reentrantly access `INSTANCE` - let stdin = match stdin_raw() { - Ok(stdin) => Maybe::Real(stdin), - _ => Maybe::Fake, - }; - - Arc::new(Mutex::new(BufReader::with_capacity(stdio::STDIN_BUF_SIZE, stdin))) - } -} - -impl Stdin { - /// Locks this handle to the standard input stream, returning a readable - /// guard. - /// - /// The lock is released when the returned lock goes out of scope. The - /// returned guard also implements the [`Read`] and [`BufRead`] traits for - /// accessing the underlying data. - /// - /// [`Read`]: trait.Read.html - /// [`BufRead`]: trait.BufRead.html - /// - /// # Examples - /// - /// ```no_run - /// use std::io::{self, Read}; - /// - /// fn main() -> io::Result<()> { - /// let mut buffer = String::new(); - /// let stdin = io::stdin(); - /// let mut handle = stdin.lock(); - /// - /// handle.read_to_string(&mut buffer)?; - /// Ok(()) - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn lock(&self) -> StdinLock<'_> { - StdinLock { inner: self.inner.lock().unwrap_or_else(|e| e.into_inner()) } - } - - /// Locks this handle and reads a line of input, appending it to the specified buffer. - /// - /// For detailed semantics of this method, see the documentation on - /// [`BufRead::read_line`]. - /// - /// [`BufRead::read_line`]: trait.BufRead.html#method.read_line - /// - /// # Examples - /// - /// ```no_run - /// use std::io; - /// - /// let mut input = String::new(); - /// match io::stdin().read_line(&mut input) { - /// Ok(n) => { - /// println!("{} bytes read", n); - /// println!("{}", input); - /// } - /// Err(error) => println!("error: {}", error), - /// } - /// ``` - /// - /// You can run the example one of two ways: - /// - /// - Pipe some text to it, e.g., `printf foo | path/to/executable` - /// - Give it text interactively by running the executable directly, - /// in which case it will wait for the Enter key to be pressed before - /// continuing - #[stable(feature = "rust1", since = "1.0.0")] - pub fn read_line(&self, buf: &mut String) -> io::Result<usize> { - self.lock().read_line(buf) - } -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl fmt::Debug for Stdin { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.pad("Stdin { .. }") - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl Read for Stdin { - fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { - self.lock().read(buf) - } - fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> { - self.lock().read_vectored(bufs) - } - #[inline] - fn is_read_vectored(&self) -> bool { - self.lock().is_read_vectored() - } - #[inline] - unsafe fn initializer(&self) -> Initializer { - Initializer::nop() - } - fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> { - self.lock().read_to_end(buf) - } - fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> { - self.lock().read_to_string(buf) - } - fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> { - self.lock().read_exact(buf) - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl Read for StdinLock<'_> { - fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { - self.inner.read(buf) - } - - fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> { - self.inner.read_vectored(bufs) - } - - #[inline] - fn is_read_vectored(&self) -> bool { - self.inner.is_read_vectored() - } - - #[inline] - unsafe fn initializer(&self) -> Initializer { - Initializer::nop() - } - - fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> { - self.inner.read_to_end(buf) - } - - fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> { - self.inner.read_to_string(buf) - } - - fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> { - self.inner.read_exact(buf) - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl BufRead for StdinLock<'_> { - fn fill_buf(&mut self) -> io::Result<&[u8]> { - self.inner.fill_buf() - } - - fn consume(&mut self, n: usize) { - self.inner.consume(n) - } - - fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> { - self.inner.read_until(byte, buf) - } - - fn read_line(&mut self, buf: &mut String) -> io::Result<usize> { - self.inner.read_line(buf) - } -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl fmt::Debug for StdinLock<'_> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.pad("StdinLock { .. }") - } -} - -/// A handle to the global standard output stream of the current process. -/// -/// Each handle shares a global buffer of data to be written to the standard -/// output stream. Access is also synchronized via a lock and explicit control -/// over locking is available via the [`lock`] method. -/// -/// Created by the [`io::stdout`] method. -/// -/// ### Note: Windows Portability Consideration -/// When operating in a console, the Windows implementation of this stream does not support -/// non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return -/// an error. -/// -/// [`lock`]: #method.lock -/// [`io::stdout`]: fn.stdout.html -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Stdout { - // FIXME: this should be LineWriter or BufWriter depending on the state of - // stdout (tty or not). Note that if this is not line buffered it - // should also flush-on-panic or some form of flush-on-abort. - inner: Arc<ReentrantMutex<RefCell<LineWriter<Maybe<StdoutRaw>>>>>, -} - -/// A locked reference to the `Stdout` handle. -/// -/// This handle implements the [`Write`] trait, and is constructed via -/// the [`Stdout::lock`] method. -/// -/// ### Note: Windows Portability Consideration -/// When operating in a console, the Windows implementation of this stream does not support -/// non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return -/// an error. -/// -/// [`Write`]: trait.Write.html -/// [`Stdout::lock`]: struct.Stdout.html#method.lock -#[stable(feature = "rust1", since = "1.0.0")] -pub struct StdoutLock<'a> { - inner: ReentrantMutexGuard<'a, RefCell<LineWriter<Maybe<StdoutRaw>>>>, -} - -/// Constructs a new handle to the standard output of the current process. -/// -/// Each handle returned is a reference to a shared global buffer whose access -/// is synchronized via a mutex. If you need more explicit control over -/// locking, see the [`Stdout::lock`] method. -/// -/// [`Stdout::lock`]: struct.Stdout.html#method.lock -/// -/// ### Note: Windows Portability Consideration -/// When operating in a console, the Windows implementation of this stream does not support -/// non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return -/// an error. -/// -/// # Examples -/// -/// Using implicit synchronization: -/// -/// ```no_run -/// use std::io::{self, Write}; -/// -/// fn main() -> io::Result<()> { -/// io::stdout().write_all(b"hello world")?; -/// -/// Ok(()) -/// } -/// ``` -/// -/// Using explicit synchronization: -/// -/// ```no_run -/// use std::io::{self, Write}; -/// -/// fn main() -> io::Result<()> { -/// let stdout = io::stdout(); -/// let mut handle = stdout.lock(); -/// -/// handle.write_all(b"hello world")?; -/// -/// Ok(()) -/// } -/// ``` -#[stable(feature = "rust1", since = "1.0.0")] -pub fn stdout() -> Stdout { - static INSTANCE: Lazy<ReentrantMutex<RefCell<LineWriter<Maybe<StdoutRaw>>>>> = Lazy::new(); - return Stdout { - inner: unsafe { INSTANCE.get(stdout_init).expect("cannot access stdout during shutdown") }, - }; - - fn stdout_init() -> Arc<ReentrantMutex<RefCell<LineWriter<Maybe<StdoutRaw>>>>> { - // This must not reentrantly access `INSTANCE` - let stdout = match stdout_raw() { - Ok(stdout) => Maybe::Real(stdout), - _ => Maybe::Fake, - }; - unsafe { - let ret = Arc::new(ReentrantMutex::new(RefCell::new(LineWriter::new(stdout)))); - ret.init(); - ret - } - } -} - -impl Stdout { - /// Locks this handle to the standard output stream, returning a writable - /// guard. - /// - /// The lock is released when the returned lock goes out of scope. The - /// returned guard also implements the `Write` trait for writing data. - /// - /// # Examples - /// - /// ```no_run - /// use std::io::{self, Write}; - /// - /// fn main() -> io::Result<()> { - /// let stdout = io::stdout(); - /// let mut handle = stdout.lock(); - /// - /// handle.write_all(b"hello world")?; - /// - /// Ok(()) - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn lock(&self) -> StdoutLock<'_> { - StdoutLock { inner: self.inner.lock() } - } -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl fmt::Debug for Stdout { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.pad("Stdout { .. }") - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl Write for Stdout { - fn write(&mut self, buf: &[u8]) -> io::Result<usize> { - self.lock().write(buf) - } - fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { - self.lock().write_vectored(bufs) - } - #[inline] - fn is_write_vectored(&self) -> bool { - self.lock().is_write_vectored() - } - fn flush(&mut self) -> io::Result<()> { - self.lock().flush() - } - fn write_all(&mut self, buf: &[u8]) -> io::Result<()> { - self.lock().write_all(buf) - } - fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> io::Result<()> { - self.lock().write_all_vectored(bufs) - } - fn write_fmt(&mut self, args: fmt::Arguments<'_>) -> io::Result<()> { - self.lock().write_fmt(args) - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl Write for StdoutLock<'_> { - fn write(&mut self, buf: &[u8]) -> io::Result<usize> { - self.inner.borrow_mut().write(buf) - } - fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { - self.inner.borrow_mut().write_vectored(bufs) - } - #[inline] - fn is_write_vectored(&self) -> bool { - self.inner.borrow_mut().is_write_vectored() - } - fn flush(&mut self) -> io::Result<()> { - self.inner.borrow_mut().flush() - } - fn write_all(&mut self, buf: &[u8]) -> io::Result<()> { - self.inner.borrow_mut().write_all(buf) - } - fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> io::Result<()> { - self.inner.borrow_mut().write_all_vectored(bufs) - } -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl fmt::Debug for StdoutLock<'_> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.pad("StdoutLock { .. }") - } -} - -/// A handle to the standard error stream of a process. -/// -/// For more information, see the [`io::stderr`] method. -/// -/// [`io::stderr`]: fn.stderr.html -/// -/// ### Note: Windows Portability Consideration -/// When operating in a console, the Windows implementation of this stream does not support -/// non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return -/// an error. -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Stderr { - inner: &'static ReentrantMutex<RefCell<Maybe<StderrRaw>>>, -} - -/// A locked reference to the `Stderr` handle. -/// -/// This handle implements the `Write` trait and is constructed via -/// the [`Stderr::lock`] method. -/// -/// [`Stderr::lock`]: struct.Stderr.html#method.lock -/// -/// ### Note: Windows Portability Consideration -/// When operating in a console, the Windows implementation of this stream does not support -/// non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return -/// an error. -#[stable(feature = "rust1", since = "1.0.0")] -pub struct StderrLock<'a> { - inner: ReentrantMutexGuard<'a, RefCell<Maybe<StderrRaw>>>, -} - -/// Constructs a new handle to the standard error of the current process. -/// -/// This handle is not buffered. -/// -/// ### Note: Windows Portability Consideration -/// When operating in a console, the Windows implementation of this stream does not support -/// non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return -/// an error. -/// -/// # Examples -/// -/// Using implicit synchronization: -/// -/// ```no_run -/// use std::io::{self, Write}; -/// -/// fn main() -> io::Result<()> { -/// io::stderr().write_all(b"hello world")?; -/// -/// Ok(()) -/// } -/// ``` -/// -/// Using explicit synchronization: -/// -/// ```no_run -/// use std::io::{self, Write}; -/// -/// fn main() -> io::Result<()> { -/// let stderr = io::stderr(); -/// let mut handle = stderr.lock(); -/// -/// handle.write_all(b"hello world")?; -/// -/// Ok(()) -/// } -/// ``` -#[stable(feature = "rust1", since = "1.0.0")] -pub fn stderr() -> Stderr { - // Note that unlike `stdout()` we don't use `Lazy` here which registers a - // destructor. Stderr is not buffered nor does the `stderr_raw` type consume - // any owned resources, so there's no need to run any destructors at some - // point in the future. - // - // This has the added benefit of allowing `stderr` to be usable during - // process shutdown as well! - static INSTANCE: ReentrantMutex<RefCell<Maybe<StderrRaw>>> = - unsafe { ReentrantMutex::new(RefCell::new(Maybe::Fake)) }; - - // When accessing stderr we need one-time initialization of the reentrant - // mutex, followed by one-time detection of whether we actually have a - // stderr handle or not. Afterwards we can just always use the now-filled-in - // `INSTANCE` value. - static INIT: Once = Once::new(); - INIT.call_once(|| unsafe { - INSTANCE.init(); - if let Ok(stderr) = stderr_raw() { - *INSTANCE.lock().borrow_mut() = Maybe::Real(stderr); - } - }); - Stderr { inner: &INSTANCE } -} - -impl Stderr { - /// Locks this handle to the standard error stream, returning a writable - /// guard. - /// - /// The lock is released when the returned lock goes out of scope. The - /// returned guard also implements the `Write` trait for writing data. - /// - /// # Examples - /// - /// ``` - /// use std::io::{self, Write}; - /// - /// fn foo() -> io::Result<()> { - /// let stderr = io::stderr(); - /// let mut handle = stderr.lock(); - /// - /// handle.write_all(b"hello world")?; - /// - /// Ok(()) - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn lock(&self) -> StderrLock<'_> { - StderrLock { inner: self.inner.lock() } - } -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl fmt::Debug for Stderr { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.pad("Stderr { .. }") - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl Write for Stderr { - fn write(&mut self, buf: &[u8]) -> io::Result<usize> { - self.lock().write(buf) - } - fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { - self.lock().write_vectored(bufs) - } - #[inline] - fn is_write_vectored(&self) -> bool { - self.lock().is_write_vectored() - } - fn flush(&mut self) -> io::Result<()> { - self.lock().flush() - } - fn write_all(&mut self, buf: &[u8]) -> io::Result<()> { - self.lock().write_all(buf) - } - fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> io::Result<()> { - self.lock().write_all_vectored(bufs) - } - fn write_fmt(&mut self, args: fmt::Arguments<'_>) -> io::Result<()> { - self.lock().write_fmt(args) - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl Write for StderrLock<'_> { - fn write(&mut self, buf: &[u8]) -> io::Result<usize> { - self.inner.borrow_mut().write(buf) - } - fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> { - self.inner.borrow_mut().write_vectored(bufs) - } - #[inline] - fn is_write_vectored(&self) -> bool { - self.inner.borrow_mut().is_write_vectored() - } - fn flush(&mut self) -> io::Result<()> { - self.inner.borrow_mut().flush() - } - fn write_all(&mut self, buf: &[u8]) -> io::Result<()> { - self.inner.borrow_mut().write_all(buf) - } - fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> io::Result<()> { - self.inner.borrow_mut().write_all_vectored(bufs) - } -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl fmt::Debug for StderrLock<'_> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.pad("StderrLock { .. }") - } -} - -/// Resets the thread-local stderr handle to the specified writer -/// -/// This will replace the current thread's stderr handle, returning the old -/// handle. All future calls to `panic!` and friends will emit their output to -/// this specified handle. -/// -/// Note that this does not need to be called for all new threads; the default -/// output handle is to the process's stderr stream. -#[unstable( - feature = "set_stdio", - reason = "this function may disappear completely or be replaced \ - with a more general mechanism", - issue = "none" -)] -#[doc(hidden)] -pub fn set_panic(sink: Option<Box<dyn Write + Send>>) -> Option<Box<dyn Write + Send>> { - use crate::mem; - LOCAL_STDERR.with(move |slot| mem::replace(&mut *slot.borrow_mut(), sink)).and_then(|mut s| { - let _ = s.flush(); - Some(s) - }) -} - -/// Resets the thread-local stdout handle to the specified writer -/// -/// This will replace the current thread's stdout handle, returning the old -/// handle. All future calls to `print!` and friends will emit their output to -/// this specified handle. -/// -/// Note that this does not need to be called for all new threads; the default -/// output handle is to the process's stdout stream. -#[unstable( - feature = "set_stdio", - reason = "this function may disappear completely or be replaced \ - with a more general mechanism", - issue = "none" -)] -#[doc(hidden)] -pub fn set_print(sink: Option<Box<dyn Write + Send>>) -> Option<Box<dyn Write + Send>> { - use crate::mem; - LOCAL_STDOUT.with(move |slot| mem::replace(&mut *slot.borrow_mut(), sink)).and_then(|mut s| { - let _ = s.flush(); - Some(s) - }) -} - -/// Write `args` to output stream `local_s` if possible, `global_s` -/// otherwise. `label` identifies the stream in a panic message. -/// -/// This function is used to print error messages, so it takes extra -/// care to avoid causing a panic when `local_s` is unusable. -/// For instance, if the TLS key for the local stream is -/// already destroyed, or if the local stream is locked by another -/// thread, it will just fall back to the global stream. -/// -/// However, if the actual I/O causes an error, this function does panic. -fn print_to<T>( - args: fmt::Arguments<'_>, - local_s: &'static LocalKey<RefCell<Option<Box<dyn Write + Send>>>>, - global_s: fn() -> T, - label: &str, -) where - T: Write, -{ - let result = local_s - .try_with(|s| { - // Note that we completely remove a local sink to write to in case - // our printing recursively panics/prints, so the recursive - // panic/print goes to the global sink instead of our local sink. - let prev = s.borrow_mut().take(); - if let Some(mut w) = prev { - let result = w.write_fmt(args); - *s.borrow_mut() = Some(w); - return result; - } - global_s().write_fmt(args) - }) - .unwrap_or_else(|_| global_s().write_fmt(args)); - - if let Err(e) = result { - panic!("failed printing to {}: {}", label, e); - } -} - -#[unstable( - feature = "print_internals", - reason = "implementation detail which may disappear or be replaced at any time", - issue = "none" -)] -#[doc(hidden)] -#[cfg(not(test))] -pub fn _print(args: fmt::Arguments<'_>) { - print_to(args, &LOCAL_STDOUT, stdout, "stdout"); -} - -#[unstable( - feature = "print_internals", - reason = "implementation detail which may disappear or be replaced at any time", - issue = "none" -)] -#[doc(hidden)] -#[cfg(not(test))] -pub fn _eprint(args: fmt::Arguments<'_>) { - print_to(args, &LOCAL_STDERR, stderr, "stderr"); -} - -#[cfg(test)] -pub use realstd::io::{_eprint, _print}; - -#[cfg(test)] -mod tests { - use super::*; - use crate::panic::{RefUnwindSafe, UnwindSafe}; - use crate::thread; - - #[test] - fn stdout_unwind_safe() { - assert_unwind_safe::<Stdout>(); - } - #[test] - fn stdoutlock_unwind_safe() { - assert_unwind_safe::<StdoutLock<'_>>(); - assert_unwind_safe::<StdoutLock<'static>>(); - } - #[test] - fn stderr_unwind_safe() { - assert_unwind_safe::<Stderr>(); - } - #[test] - fn stderrlock_unwind_safe() { - assert_unwind_safe::<StderrLock<'_>>(); - assert_unwind_safe::<StderrLock<'static>>(); - } - - fn assert_unwind_safe<T: UnwindSafe + RefUnwindSafe>() {} - - #[test] - #[cfg_attr(target_os = "emscripten", ignore)] - fn panic_doesnt_poison() { - thread::spawn(|| { - let _a = stdin(); - let _a = _a.lock(); - let _a = stdout(); - let _a = _a.lock(); - let _a = stderr(); - let _a = _a.lock(); - panic!(); - }) - .join() - .unwrap_err(); - - let _a = stdin(); - let _a = _a.lock(); - let _a = stdout(); - let _a = _a.lock(); - let _a = stderr(); - let _a = _a.lock(); - } -} |