ts/executor: replace tokio with smol-like implementation

The threadshare executor was based on a modified version of tokio
which implemented the throttling strategy in the BasicScheduler.
Upstream tokio codebase has significantly diverged from what it
was when the throttling strategy was implemented making it hard
to follow. This means that we can hardly get updates from the
upstream project and when we cherry pick fixes, we can't reflect
the state of the project on our fork's version. As a consequence,
tools such as cargo-deny can't check for RUSTSEC fixes in our fork.

The smol ecosystem makes it quite easy to implement and maintain
a custom async executor. This MR imports the smol parts that
need modifications to comply with the threadshare model and implements
a throttling executor in place of the tokio fork.

Networking tokio specific types are replaced with Async wrappers
in the spirit of [smol-rs/async-io]. Note however that the Async
wrappers needed modifications in order to use the per thread
Reactor model. This means that higher level upstream networking
crates such as [async-net] can not be used with our Async
implementation.

Based on the example benchmark with ts-udpsrc, performances seem on par
with what we achieved using the tokio fork.

Fixes https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/issues/118

Related to https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/604

1 files changed, 6 insertions, 6 deletions

diff --git a/generic/threadshare/src/socket.rs b/generic/threadshare/src/socket.rs
index 420e0f345..0e544c3e4 100644
--- a/generic/threadshare/src/socket.rs
+++ b/generic/threadshare/src/socket.rs
@@ -24,12 +24,14 @@ use gst::{gst_debug, gst_error, gst_log};
 
 use once_cell::sync::Lazy;
 
-use std::io;
-
 use gio::prelude::*;
 
 use std::error;
 use std::fmt;
+use std::io;
+use std::net::UdpSocket;
+
+use crate::runtime::Async;
 
 #[cfg(unix)]
 use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
@@ -302,7 +304,7 @@ unsafe fn dup_socket(socket: usize) -> usize {
     socket
 }
 
-pub fn wrap_socket(socket: &tokio::net::UdpSocket) -> Result<GioSocketWrapper, gst::ErrorMessage> {
+pub fn wrap_socket(socket: &Async<UdpSocket>) -> Result<GioSocketWrapper, gst::ErrorMessage> {
     #[cfg(unix)]
     unsafe {
         let fd = libc::dup(socket.as_raw_fd());
@@ -328,9 +330,7 @@ pub fn wrap_socket(socket: &tokio::net::UdpSocket) -> Result<GioSocketWrapper, g
     }
     #[cfg(windows)]
     unsafe {
-        // FIXME: Needs https://github.com/tokio-rs/tokio/pull/806
-        // and https://github.com/carllerche/mio/pull/859
-        let fd = unreachable!(); //dup_socket(socket.as_raw_socket() as _) as _;
+        let fd = socket.as_raw_socket();
 
         // This is unsafe because it allows us to share the fd between the socket and the
         // GIO socket below, but safety of this is the job of the application