Move futures based BusStream from examples to the bindings

And hide behind the "futures" feature.

Fixes https://github.com/sdroege/gstreamer-rs/issues/26

Cargo.lock

@@ -253,6 +253,7 @@ name = "gstreamer"
 version = "0.1.0"
 dependencies = [
  "bitflags 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "glib 0.1.3 (git+https://github.com/gtk-rs/glib)",
  "glib-sys 0.3.4 (git+https://github.com/gtk-rs/sys)",
  "gobject-sys 0.3.4 (git+https://github.com/gtk-rs/sys)",

examples/Cargo.toml

@@ -12,13 +12,14 @@ gstreamer-video = { path = "../gstreamer-video" }
 gstreamer-player = { path = "../gstreamer-player", optional = true }
 gtk = { version = "0.1.3", git = "https://github.com/gtk-rs/gtk", features = ["v3_6"] }
 gio = { version = "0.1.3", git = "https://github.com/gtk-rs/gio" }
-futures = "0.1"
-tokio-core = "0.1"
+futures = { version = "0.1", optional = true }
+tokio-core = { version = "0.1", optional = true }
 send-cell = "0.1"
 byte-slice-cast = "0.1"
 
 [features]
 gst-player = ["gstreamer-player"]
+tokio = ["gstreamer/futures", "futures", "tokio-core"]
 default-features = []
 
 [badges]

examples/src/bin/tokio.rs

@@ -1,60 +1,20 @@
 extern crate gstreamer as gst;
+#[cfg(feature = "tokio")]
 use gst::*;
 
+#[cfg(feature = "tokio")]
 extern crate futures;
-use futures::{Async, Poll};
-use futures::task::Task;
+#[cfg(feature = "tokio")]
 use futures::stream::Stream;
+#[cfg(feature = "tokio")]
 extern crate tokio_core;
+#[cfg(feature = "tokio")]
 use tokio_core::reactor::Core;
 
+#[cfg(feature = "tokio")]
 use std::env;
-use std::sync::{Arc, Mutex};
-
-struct BusStream(Bus, Arc<Mutex<Option<Task>>>);
-
-impl BusStream {
-    fn new(bus: &Bus) -> Self {
-        let task = Arc::new(Mutex::new(None));
-        let task_clone = task.clone();
-
-        bus.set_sync_handler(move |_, _| {
-            let mut task = task_clone.lock().unwrap();
-            if let Some(task) = task.take() {
-                // FIXME: Force type...
-                let task: Task = task;
-                task.notify();
-            }
-
-            BusSyncReply::Pass
-        });
-        BusStream(bus.clone(), task)
-    }
-}
-
-impl Drop for BusStream {
-    fn drop(&mut self) {
-        self.0.unset_sync_handler();
-    }
-}
-
-impl Stream for BusStream {
-    type Item = Message;
-    type Error = ();
-
-    fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error> {
-        let mut task = self.1.lock().unwrap();
-
-        let msg = self.0.pop();
-        if let Some(msg) = msg {
-            Ok(Async::Ready(Some(msg)))
-        } else {
-            *task = Some(futures::task::current());
-            Ok(Async::NotReady)
-        }
-    }
-}
 
+#[cfg(feature = "tokio")]
 fn main() {
     let pipeline_str = env::args().collect::<Vec<String>>()[1..].join(" ");
 
@@ -95,3 +55,8 @@ fn main() {
     let ret = pipeline.set_state(gst::State::Null);
     assert_ne!(ret, gst::StateChangeReturn::Failure);
 }
+
+#[cfg(not(feature = "tokio"))]
+fn main() {
+    println!("Please compile with --features tokio");
+}

gstreamer/Cargo.toml

@@ -19,6 +19,7 @@ gstreamer-sys = { version = "0.1.1", git = "https://github.com/sdroege/gstreamer
 glib = { version = "0.1.3", git = "https://github.com/gtk-rs/glib" }
 num-rational = { version = "0.1.38", default-features = false, features = [] }
 lazy_static = "0.2"
+futures = { version = "0.1", optional = true }
 
 [build-dependencies.rustdoc-stripper]
 version = "0.1"

gstreamer/src/bus.rs

@@ -16,6 +16,17 @@ use glib_ffi;
 use glib_ffi::{gboolean, gpointer};
 use std::ptr;
 
+#[cfg(feature = "futures")]
+use std::sync::{Arc, Mutex};
+#[cfg(feature = "futures")]
+use futures;
+#[cfg(feature = "futures")]
+use futures::{Async, Poll};
+#[cfg(feature = "futures")]
+use futures::task::Task;
+#[cfg(feature = "futures")]
+use futures::stream::Stream;
+
 use Bus;
 use BusSyncReply;
 use Message;
@@ -129,3 +140,52 @@ impl Bus {
         unsafe { ffi::gst_bus_set_sync_handler(self.to_glib_none().0, None, ptr::null_mut(), None) }
     }
 }
+
+#[cfg(feature = "futures")]
+pub struct BusStream(Bus, Arc<Mutex<Option<Task>>>);
+
+#[cfg(feature = "futures")]
+impl BusStream {
+    pub fn new(bus: &Bus) -> Self {
+        let task = Arc::new(Mutex::new(None));
+        let task_clone = task.clone();
+
+        bus.set_sync_handler(move |_, _| {
+            let mut task = task_clone.lock().unwrap();
+            if let Some(task) = task.take() {
+                // FIXME: Force type...
+                let task: Task = task;
+                task.notify();
+            }
+
+            BusSyncReply::Pass
+        });
+
+        BusStream(bus.clone(), task)
+    }
+}
+
+#[cfg(feature = "futures")]
+impl Drop for BusStream {
+    fn drop(&mut self) {
+        self.0.unset_sync_handler();
+    }
+}
+
+#[cfg(feature = "futures")]
+impl Stream for BusStream {
+    type Item = Message;
+    type Error = ();
+
+    fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error> {
+        let mut task = self.1.lock().unwrap();
+
+        let msg = self.0.pop();
+        if let Some(msg) = msg {
+            Ok(Async::Ready(Some(msg)))
+        } else {
+            *task = Some(futures::task::current());
+            Ok(Async::NotReady)
+        }
+    }
+}

gstreamer/src/lib.rs

@@ -22,6 +22,9 @@ extern crate glib;
 
 extern crate num_rational;
 
+#[cfg(feature = "futures")]
+extern crate futures;
+
 use glib::translate::{from_glib, from_glib_full};
 
 macro_rules! callback_guard {
@@ -102,6 +105,8 @@ pub use child_proxy::ChildProxyExtManual;
 pub use tag_setter::TagSetterExtManual;
 pub use self::iterator::Iterator;
 pub use device_provider::DeviceProviderExtManual;
+#[cfg(feature = "futures")]
+pub use bus::BusStream;
 
 mod value;
 pub use value::*;