Add and use new Signals struct (#13314)

# Description
This PR introduces a new `Signals` struct to replace our adhoc passing
around of `ctrlc: Option<Arc<AtomicBool>>`. Doing so has a few benefits:
- We can better enforce when/where resetting or triggering an interrupt
is allowed.
- Consolidates `nu_utils::ctrl_c::was_pressed` and other ad-hoc
re-implementations into a single place: `Signals::check`.
- This allows us to add other types of signals later if we want. E.g.,
exiting or suspension.
- Similarly, we can more easily change the underlying implementation if
we need to in the future.
- Places that used to have a `ctrlc` of `None` now use
`Signals::empty()`, so we can double check these usages for correctness
in the future.

crates/nu-plugin-core/src/interface/mod.rs

@@ -1,10 +1,10 @@
 //! Implements the stream multiplexing interface for both the plugin side and the engine side.
 
 use nu_plugin_protocol::{ByteStreamInfo, ListStreamInfo, PipelineDataHeader, StreamMessage};
-use nu_protocol::{ByteStream, IntoSpanned, ListStream, PipelineData, Reader, ShellError};
+use nu_protocol::{ByteStream, IntoSpanned, ListStream, PipelineData, Reader, ShellError, Signals};
 use std::{
     io::{Read, Write},
-    sync::{atomic::AtomicBool, Arc, Mutex},
+    sync::Mutex,
     thread,
 };
 
@@ -170,7 +170,7 @@ pub trait InterfaceManager {
     fn read_pipeline_data(
         &self,
         header: PipelineDataHeader,
-        ctrlc: Option<&Arc<AtomicBool>>,
+        signals: &Signals,
     ) -> Result<PipelineData, ShellError> {
         self.prepare_pipeline_data(match header {
             PipelineDataHeader::Empty => PipelineData::Empty,
@@ -178,12 +178,12 @@ pub trait InterfaceManager {
             PipelineDataHeader::ListStream(info) => {
                 let handle = self.stream_manager().get_handle();
                 let reader = handle.read_stream(info.id, self.get_interface())?;
-                ListStream::new(reader, info.span, ctrlc.cloned()).into()
+                ListStream::new(reader, info.span, signals.clone()).into()
             }
             PipelineDataHeader::ByteStream(info) => {
                 let handle = self.stream_manager().get_handle();
                 let reader = handle.read_stream(info.id, self.get_interface())?;
-                ByteStream::from_result_iter(reader, info.span, ctrlc.cloned(), info.type_).into()
+                ByteStream::from_result_iter(reader, info.span, signals.clone(), info.type_).into()
             }
         })
     }

crates/nu-plugin-core/src/interface/tests.rs

@@ -11,7 +11,7 @@ use nu_plugin_protocol::{
 };
 use nu_protocol::{
     ByteStream, ByteStreamSource, ByteStreamType, DataSource, ListStream, PipelineData,
-    PipelineMetadata, ShellError, Span, Value,
+    PipelineMetadata, ShellError, Signals, Span, Value,
 };
 use std::{path::Path, sync::Arc};
 
@@ -129,7 +129,7 @@ fn read_pipeline_data_empty() -> Result<(), ShellError> {
     let header = PipelineDataHeader::Empty;
 
     assert!(matches!(
-        manager.read_pipeline_data(header, None)?,
+        manager.read_pipeline_data(header, &Signals::empty())?,
         PipelineData::Empty
     ));
     Ok(())
@@ -141,7 +141,7 @@ fn read_pipeline_data_value() -> Result<(), ShellError> {
     let value = Value::test_int(4);
     let header = PipelineDataHeader::Value(value.clone());
 
-    match manager.read_pipeline_data(header, None)? {
+    match manager.read_pipeline_data(header, &Signals::empty())? {
         PipelineData::Value(read_value, ..) => assert_eq!(value, read_value),
         PipelineData::ListStream(..) => panic!("unexpected ListStream"),
         PipelineData::ByteStream(..) => panic!("unexpected ByteStream"),
@@ -168,7 +168,7 @@ fn read_pipeline_data_list_stream() -> Result<(), ShellError> {
         span: Span::test_data(),
     });
 
-    let pipe = manager.read_pipeline_data(header, None)?;
+    let pipe = manager.read_pipeline_data(header, &Signals::empty())?;
     assert!(
         matches!(pipe, PipelineData::ListStream(..)),
         "unexpected PipelineData: {pipe:?}"
@@ -212,7 +212,7 @@ fn read_pipeline_data_byte_stream() -> Result<(), ShellError> {
         type_: ByteStreamType::Unknown,
     });
 
-    let pipe = manager.read_pipeline_data(header, None)?;
+    let pipe = manager.read_pipeline_data(header, &Signals::empty())?;
 
     // need to consume input
     manager.consume_all()?;
@@ -257,7 +257,7 @@ fn read_pipeline_data_prepared_properly() -> Result<(), ShellError> {
         id: 0,
         span: Span::test_data(),
     });
-    match manager.read_pipeline_data(header, None)? {
+    match manager.read_pipeline_data(header, &Signals::empty())? {
         PipelineData::ListStream(_, meta) => match meta {
             Some(PipelineMetadata { data_source, .. }) => match data_source {
                 DataSource::FilePath(path) => {
@@ -353,7 +353,11 @@ fn write_pipeline_data_list_stream() -> Result<(), ShellError> {
 
     // Set up pipeline data for a list stream
     let pipe = PipelineData::ListStream(
-        ListStream::new(values.clone().into_iter(), Span::test_data(), None),
+        ListStream::new(
+            values.clone().into_iter(),
+            Span::test_data(),
+            Signals::empty(),
+        ),
         None,
     );
 
@@ -406,7 +410,7 @@ fn write_pipeline_data_byte_stream() -> Result<(), ShellError> {
         ByteStream::read(
             std::io::Cursor::new(expected),
             span,
-            None,
+            Signals::empty(),
             ByteStreamType::Unknown,
         ),
         None,