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Diffstat (limited to 'src/libcore/task/task.rs')
| -rw-r--r-- | src/libcore/task/task.rs | 142 |
1 files changed, 0 insertions, 142 deletions
diff --git a/src/libcore/task/task.rs b/src/libcore/task/task.rs deleted file mode 100644 index c5a41873db4..00000000000 --- a/src/libcore/task/task.rs +++ /dev/null @@ -1,142 +0,0 @@ -// Copyright 2018 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. - -#![unstable(feature = "futures_api", - reason = "futures in libcore are unstable", - issue = "50547")] - -use fmt; -use future::Future; -use mem::PinMut; -use super::{Context, Poll}; - -/// A custom trait object for polling tasks, roughly akin to -/// `Box<Future<Output = ()>>`. -/// Contrary to `TaskObj`, `LocalTaskObj` does not have a `Send` bound. -pub struct LocalTaskObj { - ptr: *mut (), - poll_fn: unsafe fn(*mut (), &mut Context) -> Poll<()>, - drop_fn: unsafe fn(*mut ()), -} - -impl LocalTaskObj { - /// Create a `LocalTaskObj` from a custom trait object representation. - #[inline] - pub fn new<T: UnsafeTask>(t: T) -> LocalTaskObj { - LocalTaskObj { - ptr: t.into_raw(), - poll_fn: T::poll, - drop_fn: T::drop, - } - } - - /// Converts the `LocalTaskObj` into a `TaskObj` - /// To make this operation safe one has to ensure that the `UnsafeTask` - /// instance from which this `LocalTaskObj` was created actually implements - /// `Send`. - pub unsafe fn as_task_obj(self) -> TaskObj { - TaskObj(self) - } -} - -impl fmt::Debug for LocalTaskObj { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_struct("LocalTaskObj") - .finish() - } -} - -impl From<TaskObj> for LocalTaskObj { - fn from(task: TaskObj) -> LocalTaskObj { - task.0 - } -} - -impl Future for LocalTaskObj { - type Output = (); - - #[inline] - fn poll(self: PinMut<Self>, cx: &mut Context) -> Poll<()> { - unsafe { - (self.poll_fn)(self.ptr, cx) - } - } -} - -impl Drop for LocalTaskObj { - fn drop(&mut self) { - unsafe { - (self.drop_fn)(self.ptr) - } - } -} - -/// A custom trait object for polling tasks, roughly akin to -/// `Box<Future<Output = ()> + Send>`. -pub struct TaskObj(LocalTaskObj); - -unsafe impl Send for TaskObj {} - -impl TaskObj { - /// Create a `TaskObj` from a custom trait object representation. - #[inline] - pub fn new<T: UnsafeTask + Send>(t: T) -> TaskObj { - TaskObj(LocalTaskObj::new(t)) - } -} - -impl fmt::Debug for TaskObj { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_struct("TaskObj") - .finish() - } -} - -impl Future for TaskObj { - type Output = (); - - #[inline] - fn poll(self: PinMut<Self>, cx: &mut Context) -> Poll<()> { - let pinned_field = unsafe { PinMut::map_unchecked(self, |x| &mut x.0) }; - pinned_field.poll(cx) - } -} - -/// A custom implementation of a task trait object for `TaskObj`, providing -/// a hand-rolled vtable. -/// -/// This custom representation is typically used only in `no_std` contexts, -/// where the default `Box`-based implementation is not available. -/// -/// The implementor must guarantee that it is safe to call `poll` repeatedly (in -/// a non-concurrent fashion) with the result of `into_raw` until `drop` is -/// called. -pub unsafe trait UnsafeTask: 'static { - /// Convert a owned instance into a (conceptually owned) void pointer. - fn into_raw(self) -> *mut (); - - /// Poll the task represented by the given void pointer. - /// - /// # Safety - /// - /// The trait implementor must guarantee that it is safe to repeatedly call - /// `poll` with the result of `into_raw` until `drop` is called; such calls - /// are not, however, allowed to race with each other or with calls to `drop`. - unsafe fn poll(task: *mut (), cx: &mut Context) -> Poll<()>; - - /// Drops the task represented by the given void pointer. - /// - /// # Safety - /// - /// The trait implementor must guarantee that it is safe to call this - /// function once per `into_raw` invocation; that call cannot race with - /// other calls to `drop` or `poll`. - unsafe fn drop(task: *mut ()); -} |
