Add helper method to check whether ctrl+c was pressed, adopt it (#7482)

I've been working on streaming and pipeline interruption lately. It was
bothering me that checking ctrl+c (something we want to do often) always
requires a bunch of boilerplate like:
```rust
use std::sync::atomic::Ordering;

if let Some(ctrlc) = &engine_state.ctrlc {
     if ctrlc.load(Ordering::SeqCst) {
          ...
```
I added a helper method to cut that down to:

```rust
if nu_utils::ctrl_c::was_pressed(&engine_state.ctrlc) {
    ...
```

crates/nu-command/src/core_commands/loop_.rs

@@ -1,5 +1,3 @@
-use std::sync::atomic::Ordering;
-
 use nu_engine::{eval_block, CallExt};
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Block, Command, EngineState, Stack};
@@ -44,10 +42,8 @@ impl Command for Loop {
         let block: Block = call.req(engine_state, stack, 0)?;
 
         loop {
-            if let Some(ctrlc) = &engine_state.ctrlc {
+            if nu_utils::ctrl_c::was_pressed(&engine_state.ctrlc) {
-                if ctrlc.load(Ordering::SeqCst) {
+                break;
-                    break;
-                }
             }
 
             let block = engine_state.get_block(block.block_id);

crates/nu-command/src/core_commands/while_.rs

@@ -1,5 +1,3 @@
-use std::sync::atomic::Ordering;
-
 use nu_engine::{eval_block, eval_expression, CallExt};
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Block, Command, EngineState, Stack};
@@ -48,10 +46,8 @@ impl Command for While {
         let block: Block = call.req(engine_state, stack, 1)?;
 
         loop {
-            if let Some(ctrlc) = &engine_state.ctrlc {
+            if nu_utils::ctrl_c::was_pressed(&engine_state.ctrlc) {
-                if ctrlc.load(Ordering::SeqCst) {
+                break;
-                    break;
-                }
             }
 
             let result = eval_expression(engine_state, stack, cond)?;

crates/nu-command/src/database/values/sqlite.rs

@@ -10,10 +10,7 @@ use std::{
     fs::File,
     io::Read,
     path::{Path, PathBuf},
-    sync::{
+    sync::{atomic::AtomicBool, Arc},
-        atomic::{AtomicBool, Ordering},
-        Arc,
-    },
 };
 
 const SQLITE_MAGIC_BYTES: &[u8] = "SQLite format 3\0".as_bytes();
@@ -399,14 +396,12 @@ fn prepared_statement_to_nu_list(
     let mut row_values = vec![];
 
     for row_result in row_results {
-        if let Some(ctrlc) = &ctrlc {
+        if nu_utils::ctrl_c::was_pressed(&ctrlc) {
-            if ctrlc.load(Ordering::SeqCst) {
+            // return whatever we have so far, let the caller decide whether to use it
-                // return whatever we have so far, let the caller decide whether to use it
+            return Ok(Value::List {
-                return Ok(Value::List {
+                vals: row_values,
-                    vals: row_values,
+                span: call_span,
-                    span: call_span,
+            });
-                });
-            }
         }
 
         if let Ok(row_value) = row_result {

crates/nu-command/src/filesystem/watch.rs

@@ -1,5 +1,4 @@
 use std::path::PathBuf;
-use std::sync::atomic::Ordering;
 use std::sync::mpsc::{channel, RecvTimeoutError};
 use std::time::Duration;
 
@@ -252,10 +251,8 @@ impl Command for Watch {
                 }
                 Err(RecvTimeoutError::Timeout) => {}
             }
-            if let Some(ctrlc) = ctrlc_ref {
+            if nu_utils::ctrl_c::was_pressed(ctrlc_ref) {
-                if ctrlc.load(Ordering::SeqCst) {
+                break;
-                    break;
-                }
             }
         }
 

crates/nu-command/src/filters/reduce.rs

@@ -1,5 +1,3 @@
-use std::sync::atomic::Ordering;
-
 use nu_engine::{eval_block, CallExt};
 
 use nu_protocol::ast::Call;
@@ -217,10 +215,8 @@ impl Command for Reduce {
             )?
             .into_value(span);
 
-            if let Some(ctrlc) = &ctrlc {
+            if nu_utils::ctrl_c::was_pressed(&ctrlc) {
-                if ctrlc.load(Ordering::SeqCst) {
+                break;
-                    break;
-                }
             }
         }
 

crates/nu-command/src/filters/uniq.rs

@@ -1,4 +1,3 @@
-use crate::input_handler::ctrl_c_was_pressed;
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
@@ -231,7 +230,7 @@ pub fn uniq(
     let mut uniq_values = input
         .into_iter()
         .map_while(|item| {
-            if ctrl_c_was_pressed(&ctrlc) {
+            if nu_utils::ctrl_c::was_pressed(&ctrlc) {
                 return None;
             }
             Some(item_mapper(ItemMapperState {

crates/nu-command/src/input_handler.rs

@@ -1,6 +1,6 @@
 use nu_protocol::ast::CellPath;
 use nu_protocol::{PipelineData, ShellError, Span, Value};
-use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::atomic::AtomicBool;
 use std::sync::Arc;
 
 pub trait CmdArgument {
@@ -71,12 +71,3 @@ where
         }
     }
 }
-
-// Helper method to avoid boilerplate every time we check ctrl+c
-pub fn ctrl_c_was_pressed(ctrlc: &Option<Arc<AtomicBool>>) -> bool {
-    if let Some(ctrlc) = ctrlc {
-        ctrlc.load(Ordering::SeqCst)
-    } else {
-        false
-    }
-}

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

@@ -2,7 +2,7 @@ use filesize::file_real_size_fast;
 use nu_glob::Pattern;
 use nu_protocol::{ShellError, Span, Value};
 use std::path::PathBuf;
-use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::atomic::AtomicBool;
 use std::sync::Arc;
 
 #[derive(Debug, Clone)]
@@ -106,13 +106,8 @@ impl DirInfo {
         match std::fs::read_dir(&s.path) {
             Ok(d) => {
                 for f in d {
-                    match ctrl_c {
+                    if nu_utils::ctrl_c::was_pressed(&ctrl_c) {
-                        Some(ref cc) => {
+                        break;
-                            if cc.load(Ordering::SeqCst) {
-                                break;
-                            }
-                        }
-                        None => continue,
                     }
 
                     match f {

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

@@ -6,7 +6,6 @@ use nu_protocol::{
     Type, Value,
 };
 use std::{
-    sync::atomic::Ordering,
     thread,
     time::{Duration, Instant},
 };
@@ -62,10 +61,8 @@ impl Command for Sleep {
                 break;
             }
 
-            if let Some(ctrlc) = ctrlc_ref {
+            if nu_utils::ctrl_c::was_pressed(ctrlc_ref) {
-                if ctrlc.load(Ordering::SeqCst) {
+                break;
-                    break;
-                }
             }
         }
 

crates/nu-command/src/system/run_external.rs

@@ -13,7 +13,7 @@ use std::collections::HashMap;
 use std::io::{BufRead, BufReader, Read, Write};
 use std::path::{Path, PathBuf};
 use std::process::{Command as CommandSys, Stdio};
-use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::atomic::AtomicBool;
 use std::sync::mpsc::{self, SyncSender};
 use std::sync::Arc;
 
@@ -745,10 +745,8 @@ fn read_and_redirect_message<R>(
         let length = bytes.len();
         buf_read.consume(length);
 
-        if let Some(ctrlc) = &ctrlc {
+        if nu_utils::ctrl_c::was_pressed(&ctrlc) {
-            if ctrlc.load(Ordering::SeqCst) {
+            break;
-                break;
-            }
         }
 
         match sender.send(bytes) {

crates/nu-command/src/viewers/table.rs

@@ -12,12 +12,7 @@ use nu_table::{string_width, Alignment, Table as NuTable, TableConfig, TableThem
 use nu_utils::get_ls_colors;
 use std::sync::Arc;
 use std::time::Instant;
-use std::{
+use std::{cmp::max, collections::HashMap, path::PathBuf, sync::atomic::AtomicBool};
-    cmp::max,
-    collections::HashMap,
-    path::PathBuf,
-    sync::atomic::{AtomicBool, Ordering},
-};
 use terminal_size::{Height, Width};
 use url::Url;
 
@@ -304,13 +299,8 @@ fn handle_table_command(
 
             let result = strip_output_color(result, config);
 
-            let ctrl_c_was_triggered = || match &ctrlc {
-                Some(ctrlc) => ctrlc.load(Ordering::SeqCst),
-                None => false,
-            };
-
             let result = result.unwrap_or_else(|| {
-                if ctrl_c_was_triggered() {
+                if nu_utils::ctrl_c::was_pressed(&ctrlc) {
                     "".into()
                 } else {
                     // assume this failed because the table was too wide
@@ -397,11 +387,8 @@ fn build_general_table2(
 ) -> Result<Option<String>, ShellError> {
     let mut data = Vec::with_capacity(vals.len());
     for (column, value) in cols.into_iter().zip(vals.into_iter()) {
-        // handle CTRLC event
+        if nu_utils::ctrl_c::was_pressed(&ctrlc) {
-        if let Some(ctrlc) = &ctrlc {
+            return Ok(None);
-            if ctrlc.load(Ordering::SeqCst) {
-                return Ok(None);
-            }
         }
 
         let row = vec![
@@ -460,11 +447,8 @@ fn build_expanded_table(
 
     let mut data = Vec::with_capacity(cols.len());
     for (key, value) in cols.into_iter().zip(vals) {
-        // handle CTRLC event
+        if nu_utils::ctrl_c::was_pressed(&ctrlc) {
-        if let Some(ctrlc) = &ctrlc {
+            return Ok(None);
-            if ctrlc.load(Ordering::SeqCst) {
-                return Ok(None);
-            }
         }
 
         let is_limited = matches!(expand_limit, Some(0));
@@ -810,10 +794,8 @@ fn convert_to_table(
     };
 
     for (row_num, item) in input.enumerate() {
-        if let Some(ctrlc) = &ctrlc {
+        if nu_utils::ctrl_c::was_pressed(&ctrlc) {
-            if ctrlc.load(Ordering::SeqCst) {
+            return Ok(None);
-                return Ok(None);
-            }
         }
 
         if let Value::Error { error } = item {
@@ -925,10 +907,8 @@ fn convert_to_table2<'a>(
         }
 
         for (row, item) in input.clone().into_iter().enumerate() {
-            if let Some(ctrlc) = &ctrlc {
+            if nu_utils::ctrl_c::was_pressed(&ctrlc) {
-                if ctrlc.load(Ordering::SeqCst) {
+                return Ok(None);
-                    return Ok(None);
-                }
             }
 
             if let Value::Error { error } = item {
@@ -960,10 +940,8 @@ fn convert_to_table2<'a>(
 
     if !with_header {
         for (row, item) in input.into_iter().enumerate() {
-            if let Some(ctrlc) = &ctrlc {
+            if nu_utils::ctrl_c::was_pressed(&ctrlc) {
-                if ctrlc.load(Ordering::SeqCst) {
+                return Ok(None);
-                    return Ok(None);
-                }
             }
 
             if let Value::Error { error } = item {
@@ -1019,10 +997,8 @@ fn convert_to_table2<'a>(
         data[0].push(NuTable::create_cell(&header, header_style(color_hm)));
 
         for (row, item) in input.clone().into_iter().enumerate() {
-            if let Some(ctrlc) = &ctrlc {
+            if nu_utils::ctrl_c::was_pressed(&ctrlc) {
-                if ctrlc.load(Ordering::SeqCst) {
+                return Ok(None);
-                    return Ok(None);
-                }
             }
 
             if let Value::Error { error } = item {
@@ -1059,10 +1035,8 @@ fn convert_to_table2<'a>(
             column_width = string_width(&header);
 
             for (row, item) in input.clone().into_iter().enumerate() {
-                if let Some(ctrlc) = &ctrlc {
+                if nu_utils::ctrl_c::was_pressed(&ctrlc) {
-                    if ctrlc.load(Ordering::SeqCst) {
+                    return Ok(None);
-                        return Ok(None);
-                    }
                 }
 
                 let value = create_table2_entry_basic(item, &header, head, config, color_hm);
@@ -1086,10 +1060,8 @@ fn convert_to_table2<'a>(
             column_width = string_width(&header);
 
             for (row, item) in input.clone().into_iter().enumerate() {
-                if let Some(ctrlc) = &ctrlc {
+                if nu_utils::ctrl_c::was_pressed(&ctrlc) {
-                    if ctrlc.load(Ordering::SeqCst) {
+                    return Ok(None);
-                        return Ok(None);
-                    }
                 }
 
                 let value = create_table2_entry_basic(item, &header, head, config, color_hm);
@@ -1593,10 +1565,8 @@ impl Iterator for PagingTableCreator {
                 break;
             }
 
-            if let Some(ctrlc) = &self.ctrlc {
+            if nu_utils::ctrl_c::was_pressed(&self.ctrlc) {
-                if ctrlc.load(Ordering::SeqCst) {
+                break;
-                    break;
-                }
             }
         }
 

crates/nu-engine/src/eval.rs

@@ -31,10 +31,8 @@ pub fn eval_call(
     call: &Call,
     input: PipelineData,
 ) -> Result<PipelineData, ShellError> {
-    if let Some(ctrlc) = &engine_state.ctrlc {
+    if nu_utils::ctrl_c::was_pressed(&engine_state.ctrlc) {
-        if ctrlc.load(core::sync::atomic::Ordering::SeqCst) {
+        return Ok(Value::Nothing { span: call.head }.into_pipeline_data());
-            return Ok(Value::Nothing { span: call.head }.into_pipeline_data());
-        }
     }
     let decl = engine_state.get_decl(call.decl_id);
 

crates/nu-protocol/src/value/range.rs

@@ -203,10 +203,8 @@ impl Iterator for RangeIterator {
             return None;
         }
 
-        if let Some(ctrlc) = &self.ctrlc {
+        if nu_utils::ctrl_c::was_pressed(&self.ctrlc) {
-            if ctrlc.load(core::sync::atomic::Ordering::SeqCst) {
+            return None;
-                return None;
-            }
         }
 
         let ordering = if matches!(self.end, Value::Nothing { .. }) {

crates/nu-protocol/src/value/stream.rs

@@ -1,10 +1,7 @@
 use crate::*;
 use std::{
     fmt::Debug,
-    sync::{
+    sync::{atomic::AtomicBool, Arc},
-        atomic::{AtomicBool, Ordering},
-        Arc,
-    },
 };
 
 pub struct RawStream {
@@ -77,10 +74,8 @@ impl Iterator for RawStream {
     type Item = Result<Value, ShellError>;
 
     fn next(&mut self) -> Option<Self::Item> {
-        if let Some(ctrlc) = &self.ctrlc {
+        if nu_utils::ctrl_c::was_pressed(&self.ctrlc) {
-            if ctrlc.load(Ordering::SeqCst) {
+            return None;
-                return None;
-            }
         }
 
         // If we know we're already binary, just output that
@@ -223,12 +218,8 @@ impl Iterator for ListStream {
     type Item = Value;
 
     fn next(&mut self) -> Option<Self::Item> {
-        if let Some(ctrlc) = &self.ctrlc {
+        if nu_utils::ctrl_c::was_pressed(&self.ctrlc) {
-            if ctrlc.load(Ordering::SeqCst) {
+            None
-                None
-            } else {
-                self.stream.next()
-            }
         } else {
             self.stream.next()
         }

crates/nu-utils/src/ctrl_c.rs

@@ -0,0 +1,13 @@
+use std::sync::{
+    atomic::{AtomicBool, Ordering},
+    Arc,
+};
+
+/// Returns true if Nu has received a SIGINT signal / ctrl+c event
+pub fn was_pressed(ctrlc: &Option<Arc<AtomicBool>>) -> bool {
+    if let Some(ctrlc) = ctrlc {
+        ctrlc.load(Ordering::SeqCst)
+    } else {
+        false
+    }
+}

crates/nu-utils/src/lib.rs

@@ -1,7 +1,9 @@
+pub mod ctrl_c;
 mod deansi;
 pub mod locale;
 pub mod utils;
 
+pub use ctrl_c::was_pressed;
 pub use locale::get_system_locale;
 pub use utils::{
     enable_vt_processing, get_default_config, get_default_env, get_ls_colors,