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-command/src/platform/ansi/ansi_.rs

@@ -1,11 +1,8 @@
 use nu_ansi_term::*;
 use nu_engine::command_prelude::*;
-use nu_protocol::engine::StateWorkingSet;
+use nu_protocol::{engine::StateWorkingSet, Signals};
 use once_cell::sync::Lazy;
-use std::{
-    collections::HashMap,
-    sync::{atomic::AtomicBool, Arc},
-};
+use std::collections::HashMap;
 
 #[derive(Clone)]
 pub struct AnsiCommand;
@@ -657,10 +654,13 @@ Operating system commands:
         let escape: bool = call.has_flag(engine_state, stack, "escape")?;
         let osc: bool = call.has_flag(engine_state, stack, "osc")?;
         let use_ansi_coloring = engine_state.get_config().use_ansi_coloring;
-        let ctrlc = engine_state.ctrlc.clone();
 
         if list {
-            return Ok(generate_ansi_code_list(ctrlc, call.head, use_ansi_coloring));
+            return Ok(generate_ansi_code_list(
+                engine_state.signals().clone(),
+                call.head,
+                use_ansi_coloring,
+            ));
         }
 
         // The code can now be one of the ansi abbreviations like green_bold
@@ -691,10 +691,13 @@ Operating system commands:
         let escape: bool = call.has_flag_const(working_set, "escape")?;
         let osc: bool = call.has_flag_const(working_set, "osc")?;
         let use_ansi_coloring = working_set.get_config().use_ansi_coloring;
-        let ctrlc = working_set.permanent().ctrlc.clone();
 
         if list {
-            return Ok(generate_ansi_code_list(ctrlc, call.head, use_ansi_coloring));
+            return Ok(generate_ansi_code_list(
+                working_set.permanent().signals().clone(),
+                call.head,
+                use_ansi_coloring,
+            ));
         }
 
         // The code can now be one of the ansi abbreviations like green_bold
@@ -827,7 +830,7 @@ pub fn str_to_ansi(s: &str) -> Option<String> {
 }
 
 fn generate_ansi_code_list(
-    ctrlc: Option<Arc<AtomicBool>>,
+    signals: Signals,
     call_span: Span,
     use_ansi_coloring: bool,
 ) -> PipelineData {
@@ -862,7 +865,7 @@ fn generate_ansi_code_list(
 
             Value::record(record, call_span)
         })
-        .into_pipeline_data(call_span, ctrlc)
+        .into_pipeline_data(call_span, signals.clone())
 }
 
 fn build_ansi_hashmap(v: &[AnsiCode]) -> HashMap<&str, &str> {

crates/nu-command/src/platform/ansi/link.rs

@@ -91,12 +91,12 @@ fn operate(
     if column_paths.is_empty() {
         input.map(
             move |v| process_value(&v, text.as_deref()),
-            engine_state.ctrlc.clone(),
+            engine_state.signals(),
         )
     } else {
         input.map(
             move |v| process_each_path(v, &column_paths, text.as_deref(), command_span),
-            engine_state.ctrlc.clone(),
+            engine_state.signals(),
         )
     }
 }

crates/nu-command/src/platform/ansi/strip.rs

@@ -56,7 +56,7 @@ impl Command for SubCommand {
             cell_paths,
             config: config.clone(),
         };
-        operate(action, args, input, call.head, engine_state.ctrlc.clone())
+        operate(action, args, input, call.head, engine_state.signals())
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/platform/dir_info.rs

@@ -1,10 +1,7 @@
 use filesize::file_real_size_fast;
 use nu_glob::Pattern;
-use nu_protocol::{record, ShellError, Span, Value};
-use std::{
-    path::PathBuf,
-    sync::{atomic::AtomicBool, Arc},
-};
+use nu_protocol::{record, ShellError, Signals, Span, Value};
+use std::path::PathBuf;
 
 #[derive(Debug, Clone)]
 pub struct DirBuilder {
@@ -82,8 +79,9 @@ impl DirInfo {
         path: impl Into<PathBuf>,
         params: &DirBuilder,
         depth: Option<u64>,
-        ctrl_c: Option<Arc<AtomicBool>>,
-    ) -> Self {
+        span: Span,
+        signals: &Signals,
+    ) -> Result<Self, ShellError> {
         let path = path.into();
 
         let mut s = Self {
@@ -107,14 +105,12 @@ impl DirInfo {
         match std::fs::read_dir(&s.path) {
             Ok(d) => {
                 for f in d {
-                    if nu_utils::ctrl_c::was_pressed(&ctrl_c) {
-                        break;
-                    }
+                    signals.check(span)?;
 
                     match f {
                         Ok(i) => match i.file_type() {
                             Ok(t) if t.is_dir() => {
-                                s = s.add_dir(i.path(), depth, params, ctrl_c.clone())
+                                s = s.add_dir(i.path(), depth, params, span, signals)?
                             }
                             Ok(_t) => s = s.add_file(i.path(), params),
                             Err(e) => s = s.add_error(e.into()),
@@ -125,7 +121,7 @@ impl DirInfo {
             }
             Err(e) => s = s.add_error(e.into()),
         }
-        s
+        Ok(s)
     }
 
     fn add_dir(
@@ -133,21 +129,22 @@ impl DirInfo {
         path: impl Into<PathBuf>,
         mut depth: Option<u64>,
         params: &DirBuilder,
-        ctrl_c: Option<Arc<AtomicBool>>,
-    ) -> Self {
+        span: Span,
+        signals: &Signals,
+    ) -> Result<Self, ShellError> {
         if let Some(current) = depth {
             if let Some(new) = current.checked_sub(1) {
                 depth = Some(new);
             } else {
-                return self;
+                return Ok(self);
             }
         }
 
-        let d = DirInfo::new(path, params, depth, ctrl_c);
+        let d = DirInfo::new(path, params, depth, span, signals)?;
         self.size += d.size;
         self.blocks += d.blocks;
         self.dirs.push(d);
-        self
+        Ok(self)
     }
 
     fn add_file(mut self, f: impl Into<PathBuf>, params: &DirBuilder) -> Self {

crates/nu-command/src/platform/sleep.rs

@@ -56,12 +56,7 @@ impl Command for Sleep {
                 break;
             }
             thread::sleep(CTRL_C_CHECK_INTERVAL.min(time_until_deadline));
-            // exit early if Ctrl+C was pressed
-            if nu_utils::ctrl_c::was_pressed(&engine_state.ctrlc) {
-                return Err(ShellError::InterruptedByUser {
-                    span: Some(call.head),
-                });
-            }
+            engine_state.signals().check(call.head)?;
         }
 
         Ok(Value::nothing(call.head).into_pipeline_data())