update to futures 0.1.1: alsa wasapi

examples/beep.rs

@@ -1,14 +1,27 @@
 extern crate cpal;
 extern crate futures;
 
-use futures::Future;
 use futures::stream::Stream;
+use futures::task;
+use futures::task::Executor;
+use futures::task::Run;
+
+use std::sync::Arc;
+
+struct MyExecutor;
+
+impl Executor for MyExecutor {
+    fn execute(&self, r: Run) {
+        r.run();
+    }
+}
 
 fn main() {
     let endpoint = cpal::get_default_endpoint().expect("Failed to get default endpoint");
     let format = endpoint.get_supported_formats_list().unwrap().next().expect("Failed to get endpoint format");
 
     let event_loop = cpal::EventLoop::new();
+    let executor = Arc::new(MyExecutor);
 
     let (mut voice, stream) = cpal::Voice::new(&endpoint, &format, &event_loop).expect("Failed to create a voice");
 
@@ -18,7 +31,7 @@ fn main() {
                                   .map(move |t| t.sin());
 
     voice.play();
-    stream.for_each(move |buffer| -> Result<_, ()> {
+    task::spawn(stream.for_each(move |buffer| -> Result<_, ()> {
         match buffer {
             cpal::UnknownTypeBuffer::U16(mut buffer) => {
                 for (sample, value) in buffer.chunks_mut(format.channels.len()).zip(&mut data_source) {
@@ -42,7 +55,7 @@ fn main() {
         };
 
         Ok(())
-    }).forget();
+    })).execute(executor);
 
     event_loop.run();
 }

src/alsa/mod.rs

@@ -16,9 +16,10 @@ use std::vec::IntoIter as VecIntoIter;
 use std::sync::{Arc, Mutex};
 
 use futures::Poll;
-use futures::Task;
+use futures::task::Task;
-use futures::TaskHandle;
+use futures::task;
 use futures::stream::Stream;
+use futures::Async;
 
 pub type SupportedFormatsIterator = VecIntoIter<Format>;
 
@@ -295,7 +296,7 @@ impl EventLoop {
                     if (revent as libc::c_short & libc::POLLOUT) != 0 {
                         let scheduled = current_wait.voices[i_voice].scheduled.lock().unwrap().take();
                         if let Some(scheduled) = scheduled {
-                            scheduled.notify();
+                            scheduled.unpark();
                         }
 
                         for _ in 0 .. current_wait.voices[i_voice].num_descriptors {
@@ -348,74 +349,20 @@ struct VoiceInner {
     period_len: usize,
 
     // If `Some`, something previously called `schedule` on the stream.
-    scheduled: Mutex<Option<TaskHandle>>,
+    scheduled: Mutex<Option<Task>>,
 }
 
 unsafe impl Send for VoiceInner {}
 unsafe impl Sync for VoiceInner {}
 
-impl Stream for SamplesStream {
+impl SamplesStream {
-    type Item = UnknownTypeBuffer;
-    type Error = ();
-
-    fn poll(&mut self, _: &mut Task) -> Poll<Option<Self::Item>, Self::Error> {
-        // Determine the number of samples that are available to write.
-        let available = {
-            let channel = self.inner.channel.lock().expect("could not lock channel");
-            let available = unsafe { alsa::snd_pcm_avail(*channel) };       // TODO: what about snd_pcm_avail_update?
-
-            if available == -32 {
-                // buffer underrun
-                self.inner.buffer_len
-            } else if available < 0 {
-                check_errors(available as libc::c_int).expect("buffer is not available");
-                unreachable!()
-            } else {
-                (available * self.inner.num_channels as alsa::snd_pcm_sframes_t) as usize
-            }
-        };
-
-        // If we don't have one period ready, return `NotReady`.
-        if available < self.inner.period_len {
-            return Poll::NotReady;
-        }
-
-        // We now sure that we're ready to write data.
-        match self.inner.sample_format {
-            SampleFormat::I16 => {
-                let buffer = Buffer {
-                    buffer: iter::repeat(unsafe { mem::uninitialized() }).take(available).collect(),
-                    inner: self.inner.clone(),
-                };
-
-                Poll::Ok(Some(UnknownTypeBuffer::I16(::Buffer { target: Some(buffer) })))
-            },
-            SampleFormat::U16 => {
-                let buffer = Buffer {
-                    buffer: iter::repeat(unsafe { mem::uninitialized() }).take(available).collect(),
-                    inner: self.inner.clone(),
-                };
-
-                Poll::Ok(Some(UnknownTypeBuffer::U16(::Buffer { target: Some(buffer) })))
-            },
-            SampleFormat::F32 => {
-                let buffer = Buffer {
-                    buffer: iter::repeat(unsafe { mem::uninitialized() }).take(available).collect(),
-                    inner: self.inner.clone(),
-                };
-
-                Poll::Ok(Some(UnknownTypeBuffer::F32(::Buffer { target: Some(buffer) })))
-            },
-        }
-    }
-
     #[inline]
-    fn schedule(&mut self, task: &mut Task) {
+    fn schedule(&mut self) {
         unsafe {
             let channel = self.inner.channel.lock().unwrap();
 
             // We start by filling `scheduled`.
-            *self.inner.scheduled.lock().unwrap() = Some(task.handle().clone());
+            *self.inner.scheduled.lock().unwrap() = Some(task::park());
 
             // In this function we turn the `snd_pcm_t` into a collection of file descriptors.
             // And we add these descriptors to `event_loop.pending_wait.descriptors`.
@@ -444,6 +391,63 @@ impl Stream for SamplesStream {
     }
 }
 
+impl Stream for SamplesStream {
+    type Item = UnknownTypeBuffer;
+    type Error = ();
+
+    fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error> {
+        // Determine the number of samples that are available to write.
+        let available = {
+            let channel = self.inner.channel.lock().expect("could not lock channel");
+            let available = unsafe { alsa::snd_pcm_avail(*channel) };       // TODO: what about snd_pcm_avail_update?
+
+            if available == -32 {
+                // buffer underrun
+                self.inner.buffer_len
+            } else if available < 0 {
+                check_errors(available as libc::c_int).expect("buffer is not available");
+                unreachable!()
+            } else {
+                (available * self.inner.num_channels as alsa::snd_pcm_sframes_t) as usize
+            }
+        };
+
+        // If we don't have one period ready, return `NotReady`.
+        if available < self.inner.period_len {
+            self.schedule();
+            return Ok(Async::NotReady);
+        }
+
+        // We now sure that we're ready to write data.
+        match self.inner.sample_format {
+            SampleFormat::I16 => {
+                let buffer = Buffer {
+                    buffer: iter::repeat(unsafe { mem::uninitialized() }).take(available).collect(),
+                    inner: self.inner.clone(),
+                };
+
+                Ok(Async::Ready((Some(UnknownTypeBuffer::I16(::Buffer { target: Some(buffer) })))))
+            },
+            SampleFormat::U16 => {
+                let buffer = Buffer {
+                    buffer: iter::repeat(unsafe { mem::uninitialized() }).take(available).collect(),
+                    inner: self.inner.clone(),
+                };
+
+                Ok(Async::Ready((Some(UnknownTypeBuffer::U16(::Buffer { target: Some(buffer) })))))
+            },
+            SampleFormat::F32 => {
+                let buffer = Buffer {
+                    buffer: iter::repeat(unsafe { mem::uninitialized() }).take(available).collect(),
+                    inner: self.inner.clone(),
+                };
+
+                Ok(Async::Ready((Some(UnknownTypeBuffer::F32(::Buffer { target: Some(buffer) })))))
+            },
+        }
+    }
+}
+
 /// Wrapper around `hw_params`.
 struct HwParams(*mut alsa::snd_pcm_hw_params_t);
 

src/lib.rs

@@ -22,15 +22,28 @@ The `voice` can be used to control the play/pause of the output, while the `samp
 be used to register a callback that will be called whenever the backend is ready to get data.
 See the documentation of `futures-rs` for more info about how to use streams.
 
-```ignore       // TODO: unignore
+```no_run
-# let mut samples_stream: cpal::SamplesStream = unsafe { std::mem::uninitialized() };
+# extern crate futures;
+# extern crate cpal;
+# use std::sync::Arc;
 use futures::stream::Stream;
+use futures::task;
+# struct MyExecutor;
+# impl task::Executor for MyExecutor {
+#     fn execute(&self, r: task::Run) {
+#         r.run();
+#     }
+# }
+# fn main() {
+# let mut samples_stream: cpal::SamplesStream = unsafe { std::mem::uninitialized() };
+# let my_executor = Arc::new(MyExecutor);
 
-samples_stream.for_each(move |buffer| -> Result<_, ()> {
+task::spawn(samples_stream.for_each(move |buffer| -> Result<_, ()> {
     // write data to `buffer` here
 
     Ok(())
-}).forget();
+})).execute(my_executor);
+# }
 ```
 
 TODO: add example
@@ -72,7 +85,6 @@ use std::ops::{Deref, DerefMut};
 
 use futures::stream::Stream;
 use futures::Poll;
-use futures::Task;
 
 mod null;
 mod samples_formats;
@@ -397,13 +409,8 @@ impl Stream for SamplesStream {
     type Error = ();
 
     #[inline]
-    fn poll(&mut self, task: &mut Task) -> Poll<Option<Self::Item>, Self::Error> {
+    fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error> {
-        self.0.poll(task)
+        self.0.poll()
-    }
-
-    #[inline]
-    fn schedule(&mut self, task: &mut Task) {
-        self.0.schedule(task)
     }
 }
 

src/null/mod.rs

@@ -3,8 +3,8 @@
 use std::marker::PhantomData;
 
 use futures::Poll;
-use futures::Task;
 use futures::stream::Stream;
+use futures::Async;
 
 use CreationError;
 use Format;
@@ -89,12 +89,8 @@ impl Stream for SamplesStream {
     type Error = ();
 
     #[inline]
-    fn poll(&mut self, _: &mut Task) -> Poll<Option<Self::Item>, Self::Error> {
+    fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error> {
-        Poll::NotReady
+        Ok(Async::NotReady)
-    }
-
-    #[inline]
-    fn schedule(&mut self, _: &mut Task) {
     }
 }
 

src/wasapi/voice.rs

@@ -14,9 +14,10 @@ use std::sync::Arc;
 use std::sync::Mutex;
 
 use futures::Poll;
-use futures::Task;
+use futures::task::Task;
-use futures::TaskHandle;
+use futures::task;
 use futures::stream::Stream;
+use futures::Async;
 
 use CreationError;
 use ChannelPosition;
@@ -61,7 +62,7 @@ struct EventLoopScheduled {
 
     // List of task handles corresponding to `handles`. The second element is used to signal
     // the voice that it has been signaled.
-    task_handles: Vec<(TaskHandle, Arc<AtomicBool>)>,
+    task_handles: Vec<(Task, Arc<AtomicBool>)>,
 }
 
 impl EventLoop {
@@ -118,7 +119,7 @@ impl EventLoop {
                     scheduled.handles.remove(handle_id);
                     let (task_handle, ready) = scheduled.task_handles.remove(handle_id - 1);
                     ready.store(true, Ordering::Relaxed);
-                    task_handle.notify();
+                    task_handle.unpark();
                 }
             }
         }
@@ -348,26 +349,43 @@ impl Voice {
     }
 }
 
+impl SamplesStream {
+    #[inline]
+    fn schedule(&mut self) {
+        let mut pending = self.event_loop.pending_scheduled.lock().unwrap();
+        pending.handles.push(self.event);
+        pending.task_handles.push((task::park(), self.ready.clone()));
+        drop(pending);
+
+        let result = unsafe { kernel32::SetEvent(self.event_loop.pending_scheduled_event) };
+        assert!(result != 0);
+    }
+}
+
 impl Stream for SamplesStream {
     type Item = UnknownTypeBuffer;
     type Error = ();
 
-    fn poll(&mut self, _: &mut Task) -> Poll<Option<Self::Item>, Self::Error> {
+    fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error> {
         unsafe {
             if self.ready.swap(false, Ordering::Relaxed) == false {
                 // Despite its name this function does not block, because we pass `0`.
                 let result = kernel32::WaitForSingleObject(self.event, 0);
 
-                // Returning if the event is not ready.
+                // Park the task and returning if the event is not ready.
                 match result {
                     winapi::WAIT_OBJECT_0 => (),
-                    winapi::WAIT_TIMEOUT => return Poll::NotReady,
+                    winapi::WAIT_TIMEOUT => {
+                        self.schedule();
+                        return Ok(Async::NotReady);
+                    },
                     _ => unreachable!()
                 };
             }
 
             // If we reach here, that means we're ready to accept new samples.
 
+            let poll = {
                 let mut inner = self.inner.lock().unwrap();
 
                 // Obtaining the number of frames that are available to be written.
@@ -378,7 +396,9 @@ impl Stream for SamplesStream {
                     self.max_frames_in_buffer - padding
                 };
 
-            if frames_available == 0 { return Poll::NotReady; }
+                if frames_available == 0 {
+                    Ok(Async::NotReady)
+                } else {
 
                     // Obtaining a pointer to the buffer.
                     let (buffer_data, buffer_len) = {
@@ -399,18 +419,16 @@ impl Stream for SamplesStream {
                         frames: frames_available,
                     };
 
-            Poll::Ok(Some(UnknownTypeBuffer::F32(::Buffer { target: Some(buffer) })))        // FIXME: not necessarily F32
+                    Ok(Async::Ready(Some(UnknownTypeBuffer::F32(::Buffer { target: Some(buffer) }))))        // FIXME: not necessarily F32
                 }
+            };
+
+            if let Ok(Async::NotReady) = poll {
+                self.schedule();
             }
 
-    fn schedule(&mut self, task: &mut Task) {
+            poll
-        let mut pending = self.event_loop.pending_scheduled.lock().unwrap();
+        }
-        pending.handles.push(self.event);
-        pending.task_handles.push((task.handle().clone(), self.ready.clone()));
-        drop(pending);
-
-        let result = unsafe { kernel32::SetEvent(self.event_loop.pending_scheduled_event) };
-        assert!(result != 0);
     }
 }