Implement reentrant mutexes and make stdio use them

write_fmt calls write for each formatted field. The default implementation of write_fmt is used,
which will call write on not-yet-locked stdout (and write locking after), therefore making print!
in multithreaded environment still interleave contents of two separate prints.

This patch implements reentrant mutexes, changes stdio handles to use these mutexes and overrides
write_fmt to lock the stdio handle for the whole duration of the call.

1 files changed, 0 insertions, 187 deletions

diff --git a/src/libstd/sync/poison.rs b/src/libstd/sync/poison.rs
deleted file mode 100644
index 347cd0b464e..00000000000
--- a/src/libstd/sync/poison.rs
+++ /dev/null
@@ -1,187 +0,0 @@
-// Copyright 2014 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 prelude::v1::*;
-
-use cell::UnsafeCell;
-use error::{Error};
-use fmt;
-use thread;
-
-pub struct Flag { failed: UnsafeCell<bool> }
-
-// This flag is only ever accessed with a lock previously held. Note that this
-// a totally private structure.
-unsafe impl Send for Flag {}
-unsafe impl Sync for Flag {}
-
-pub const FLAG_INIT: Flag = Flag { failed: UnsafeCell { value: false } };
-
-impl Flag {
-    #[inline]
-    pub fn borrow(&self) -> LockResult<Guard> {
-        let ret = Guard { panicking: thread::panicking() };
-        if unsafe { *self.failed.get() } {
-            Err(PoisonError::new(ret))
-        } else {
-            Ok(ret)
-        }
-    }
-
-    #[inline]
-    pub fn done(&self, guard: &Guard) {
-        if !guard.panicking && thread::panicking() {
-            unsafe { *self.failed.get() = true; }
-        }
-    }
-
-    #[inline]
-    pub fn get(&self) -> bool {
-        unsafe { *self.failed.get() }
-    }
-}
-
-pub struct Guard {
-    panicking: bool,
-}
-
-/// A type of error which can be returned whenever a lock is acquired.
-///
-/// Both Mutexes and RwLocks are poisoned whenever a task fails while the lock
-/// is held. The precise semantics for when a lock is poisoned is documented on
-/// each lock, but once a lock is poisoned then all future acquisitions will
-/// return this error.
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct PoisonError<T> {
-    guard: T,
-}
-
-/// An enumeration of possible errors which can occur while calling the
-/// `try_lock` method.
-#[stable(feature = "rust1", since = "1.0.0")]
-pub enum TryLockError<T> {
-    /// The lock could not be acquired because another task failed while holding
-    /// the lock.
-    #[stable(feature = "rust1", since = "1.0.0")]
-    Poisoned(PoisonError<T>),
-    /// The lock could not be acquired at this time because the operation would
-    /// otherwise block.
-    #[stable(feature = "rust1", since = "1.0.0")]
-    WouldBlock,
-}
-
-/// A type alias for the result of a lock method which can be poisoned.
-///
-/// The `Ok` variant of this result indicates that the primitive was not
-/// poisoned, and the `Guard` is contained within. The `Err` variant indicates
-/// that the primitive was poisoned. Note that the `Err` variant *also* carries
-/// the associated guard, and it can be acquired through the `into_inner`
-/// method.
-#[stable(feature = "rust1", since = "1.0.0")]
-pub type LockResult<Guard> = Result<Guard, PoisonError<Guard>>;
-
-/// A type alias for the result of a nonblocking locking method.
-///
-/// For more information, see `LockResult`. A `TryLockResult` doesn't
-/// necessarily hold the associated guard in the `Err` type as the lock may not
-/// have been acquired for other reasons.
-#[stable(feature = "rust1", since = "1.0.0")]
-pub type TryLockResult<Guard> = Result<Guard, TryLockError<Guard>>;
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T> fmt::Debug for PoisonError<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        "PoisonError { inner: .. }".fmt(f)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T> fmt::Display for PoisonError<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        "poisoned lock: another task failed inside".fmt(f)
-    }
-}
-
-impl<T: Send> Error for PoisonError<T> {
-    fn description(&self) -> &str {
-        "poisoned lock: another task failed inside"
-    }
-}
-
-impl<T> PoisonError<T> {
-    /// Create a `PoisonError`.
-    #[unstable(feature = "std_misc")]
-    pub fn new(guard: T) -> PoisonError<T> {
-        PoisonError { guard: guard }
-    }
-
-    /// Consumes this error indicating that a lock is poisoned, returning the
-    /// underlying guard to allow access regardless.
-    #[unstable(feature = "std_misc")]
-    pub fn into_inner(self) -> T { self.guard }
-
-    /// Reaches into this error indicating that a lock is poisoned, returning a
-    /// reference to the underlying guard to allow access regardless.
-    #[unstable(feature = "std_misc")]
-    pub fn get_ref(&self) -> &T { &self.guard }
-
-    /// Reaches into this error indicating that a lock is poisoned, returning a
-    /// mutable reference to the underlying guard to allow access regardless.
-    #[unstable(feature = "std_misc")]
-    pub fn get_mut(&mut self) -> &mut T { &mut self.guard }
-}
-
-impl<T> From<PoisonError<T>> for TryLockError<T> {
-    fn from(err: PoisonError<T>) -> TryLockError<T> {
-        TryLockError::Poisoned(err)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T> fmt::Debug for TryLockError<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match *self {
-            TryLockError::Poisoned(..) => "Poisoned(..)".fmt(f),
-            TryLockError::WouldBlock => "WouldBlock".fmt(f)
-        }
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Send> fmt::Display for TryLockError<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        self.description().fmt(f)
-    }
-}
-
-impl<T: Send> Error for TryLockError<T> {
-    fn description(&self) -> &str {
-        match *self {
-            TryLockError::Poisoned(ref p) => p.description(),
-            TryLockError::WouldBlock => "try_lock failed because the operation would block"
-        }
-    }
-
-    fn cause(&self) -> Option<&Error> {
-        match *self {
-            TryLockError::Poisoned(ref p) => Some(p),
-            _ => None
-        }
-    }
-}
-
-pub fn map_result<T, U, F>(result: LockResult<T>, f: F)
-                           -> LockResult<U>
-                           where F: FnOnce(T) -> U {
-    match result {
-        Ok(t) => Ok(f(t)),
-        Err(PoisonError { guard }) => Err(PoisonError::new(f(guard)))
-    }
-}