Add signal handlers (#3757)

1 files changed, 146 insertions, 0 deletions

diff --git a/cli/ops/signal.rs b/cli/ops/signal.rs
new file mode 100644
index 000000000..5fef02013
--- /dev/null
+++ b/cli/ops/signal.rs
@@ -0,0 +1,146 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+use super::dispatch_json::{JsonOp, Value};
+use crate::ops::json_op;
+use crate::state::ThreadSafeState;
+use deno_core::*;
+
+#[cfg(unix)]
+use super::dispatch_json::Deserialize;
+#[cfg(unix)]
+use crate::deno_error::bad_resource;
+#[cfg(unix)]
+use deno_core::Resource;
+#[cfg(unix)]
+use futures::future::{poll_fn, FutureExt};
+#[cfg(unix)]
+use serde_json;
+#[cfg(unix)]
+use std::task::Waker;
+#[cfg(unix)]
+use tokio::signal::unix::{signal, Signal, SignalKind};
+
+pub fn init(i: &mut Isolate, s: &ThreadSafeState) {
+  i.register_op(
+    "signal_bind",
+    s.core_op(json_op(s.stateful_op(op_signal_bind))),
+  );
+  i.register_op(
+    "signal_unbind",
+    s.core_op(json_op(s.stateful_op(op_signal_unbind))),
+  );
+  i.register_op(
+    "signal_poll",
+    s.core_op(json_op(s.stateful_op(op_signal_poll))),
+  );
+}
+
+#[cfg(unix)]
+/// The resource for signal stream.
+/// The second element is the waker of polling future.
+pub struct SignalStreamResource(pub Signal, pub Option<Waker>);
+
+#[cfg(unix)]
+impl Resource for SignalStreamResource {}
+
+#[cfg(unix)]
+#[derive(Deserialize)]
+struct BindSignalArgs {
+  signo: i32,
+}
+
+#[cfg(unix)]
+#[derive(Deserialize)]
+struct SignalArgs {
+  rid: i32,
+}
+
+#[cfg(unix)]
+fn op_signal_bind(
+  state: &ThreadSafeState,
+  args: Value,
+  _zero_copy: Option<PinnedBuf>,
+) -> Result<JsonOp, ErrBox> {
+  let args: BindSignalArgs = serde_json::from_value(args)?;
+  let mut table = state.lock_resource_table();
+  let rid = table.add(
+    "signal",
+    Box::new(SignalStreamResource(
+      signal(SignalKind::from_raw(args.signo)).expect(""),
+      None,
+    )),
+  );
+  Ok(JsonOp::Sync(json!({
+    "rid": rid,
+  })))
+}
+
+#[cfg(unix)]
+fn op_signal_poll(
+  state: &ThreadSafeState,
+  args: Value,
+  _zero_copy: Option<PinnedBuf>,
+) -> Result<JsonOp, ErrBox> {
+  let args: SignalArgs = serde_json::from_value(args)?;
+  let rid = args.rid as u32;
+  let state_ = state.clone();
+
+  let future = poll_fn(move |cx| {
+    let mut table = state_.lock_resource_table();
+    if let Some(mut signal) = table.get_mut::<SignalStreamResource>(rid) {
+      signal.1 = Some(cx.waker().clone());
+      return signal.0.poll_recv(cx);
+    }
+    std::task::Poll::Ready(None)
+  })
+  .then(|result| async move { Ok(json!({ "done": result.is_none() })) });
+
+  Ok(JsonOp::AsyncUnref(future.boxed()))
+}
+
+#[cfg(unix)]
+pub fn op_signal_unbind(
+  state: &ThreadSafeState,
+  args: Value,
+  _zero_copy: Option<PinnedBuf>,
+) -> Result<JsonOp, ErrBox> {
+  let args: SignalArgs = serde_json::from_value(args)?;
+  let rid = args.rid as u32;
+  let mut table = state.lock_resource_table();
+  let resource = table.get::<SignalStreamResource>(rid);
+  if let Some(signal) = resource {
+    if let Some(waker) = &signal.1 {
+      // Wakes up the pending poll if exists.
+      // This prevents the poll future from getting stuck forever.
+      waker.clone().wake();
+    }
+  }
+  table.close(rid).ok_or_else(bad_resource)?;
+  Ok(JsonOp::Sync(json!({})))
+}
+
+#[cfg(not(unix))]
+pub fn op_signal_bind(
+  _state: &ThreadSafeState,
+  _args: Value,
+  _zero_copy: Option<PinnedBuf>,
+) -> Result<JsonOp, ErrBox> {
+  unimplemented!();
+}
+
+#[cfg(not(unix))]
+fn op_signal_unbind(
+  _state: &ThreadSafeState,
+  _args: Value,
+  _zero_copy: Option<PinnedBuf>,
+) -> Result<JsonOp, ErrBox> {
+  unimplemented!();
+}
+
+#[cfg(not(unix))]
+fn op_signal_poll(
+  _state: &ThreadSafeState,
+  _args: Value,
+  _zero_copy: Option<PinnedBuf>,
+) -> Result<JsonOp, ErrBox> {
+  unimplemented!();
+}