COLUMNS

COLUMNS is part of the [POSIX
standard](https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03).

README.md

@@ -198,6 +198,16 @@ the following to your `.bashrc`:
 export HWATCH="--no-title --color --no-help-banner --border --with-scrollbar"
 ```
 
+## Execution environment
+
+When running a command, `hwatch` sets the `COLUMNS`. Many commands recognize it
+automatically (try `git diff --stat`), some others accept column width as a
+command-line argument.
+
+TODO: Link to standard.
+
+Some versions of `bash` might reset the value of `COLUMNS`; for this reason the `HWATCH_COLUMNS` environment variable is set to the same value.
+
 ## Example
 
 ### interval 10 second

src/app.rs

@@ -49,9 +49,9 @@ use crate::{
 };
 
 // local const
-use crate::Interval;
 use crate::DEFAULT_TAB_SIZE;
 use crate::HISTORY_WIDTH;
+use crate::{Interval, OutputWidthShared};
 
 ///
 #[derive(Clone, Copy, PartialEq, Eq)]
@@ -196,6 +196,9 @@ pub struct App<'a> {
     ///
     interval: Interval,
 
+    ///
+    output_width: OutputWidthShared,
+
     ///
     tab_size: u16,
 
@@ -237,7 +240,12 @@ pub struct App<'a> {
 /// Trail at watch view window.
 impl<'a> App<'a> {
     ///
-    pub fn new(tx: Sender<AppEvent>, rx: Receiver<AppEvent>, interval: Interval) -> Self {
+    pub fn new(
+        tx: Sender<AppEvent>,
+        rx: Receiver<AppEvent>,
+        interval: Interval,
+        output_width: OutputWidthShared,
+    ) -> Self {
         // method at create new view trail.
         Self {
             keymap: default_keymap(),
@@ -275,6 +283,7 @@ impl<'a> App<'a> {
             enable_summary_char: false,
 
             interval: interval.clone(),
+            output_width,
             tab_size: DEFAULT_TAB_SIZE,
 
             header_area: HeaderArea::new(*interval.read().unwrap()),
@@ -388,8 +397,15 @@ impl<'a> App<'a> {
 
     ///
     pub fn draw(&mut self, f: &mut Frame) {
+        // !!
         self.define_subareas(f.area());
 
+        {
+            let mut cur_output_width = self.output_width.write().unwrap();
+            // TODO: Account for the border
+            *cur_output_width = Some(self.watch_area.get_pane_width() as usize);
+        }
+
         if self.show_header {
             // Draw header area.
             self.header_area.draw(f);

src/exec.rs

@@ -173,6 +173,7 @@ pub struct ExecuteCommand {
     pub command: Vec<String>,
     pub is_exec: bool,
     pub is_compress: bool,
+    pub output_width: Option<usize>,
     pub tx: Sender<AppEvent>,
 }
 
@@ -184,6 +185,7 @@ impl ExecuteCommand {
             command: vec![],
             is_exec: false,
             is_compress: false,
+            output_width: None,
             tx,
         }
     }
@@ -203,11 +205,17 @@ impl ExecuteCommand {
 
         // exec command...
         let length = exec_commands.len();
-        let child_result = Command::new(&exec_commands[0])
+        let mut child_command = Command::new(&exec_commands[0]);
+        child_command
             .args(&exec_commands[1..length])
             .stdout(Stdio::piped())
-            .stderr(Stdio::piped())
-            .spawn();
+            .stderr(Stdio::piped());
+        if let Some(cols) = self.output_width {
+            child_command
+                .env("COLUMNS", cols.to_string())
+                .env("HWATCH_COLUMNS", cols.to_string());
+        }
+        let child_result = child_command.spawn();
 
         // merge stdout and stderr
         let mut vec_output = Vec::new();

src/main.rs

@@ -109,7 +109,9 @@ pub const DEFAULT_TAB_SIZE: u16 = 4;
 pub const HISTORY_WIDTH: u16 = 25;
 pub const SHELL_COMMAND_EXECCMD: &str = "{COMMAND}";
 pub const HISTORY_LIMIT: &str = "5000";
+// TODO: Change to mutex? Rename to ...Mutex?
 type Interval = Arc<RwLock<f64>>;
+type OutputWidthShared = Arc<RwLock<Option<usize>>>;
 
 // const at Windows
 #[cfg(windows)]
@@ -487,6 +489,7 @@ fn main() {
         .get_one::<f64>("interval")
         .unwrap_or(&DEFAULT_INTERVAL);
     let interval = Interval::new(override_interval.into());
+    let output_width = OutputWidthShared::new(None.into());
 
     // history limit
     let default_limit: u32 = HISTORY_LIMIT.parse().unwrap();
@@ -564,6 +567,7 @@ fn main() {
         let command: Vec<_> = command_line;
         let is_exec = m.get_flag("exec");
         let interval = interval.clone();
+        let output_width = output_width.clone();
         let _ = thread::spawn(move || loop {
             // Create cmd..
             let mut exe = exec::ExecuteCommand::new(tx.clone());
@@ -580,9 +584,12 @@ fn main() {
             // Set is exec flag.
             exe.is_exec = is_exec;
 
+            exe.output_width = *output_width.read().unwrap();
+
             // Exec command
             exe.exec_command();
 
+            // !
             let sleep_interval = *interval.read().unwrap();
             std::thread::sleep(Duration::from_secs_f64(sleep_interval));
         });
@@ -592,7 +599,7 @@ fn main() {
     if !batch {
         // is watch mode
         // Create view
-        let mut view = view::View::new(interval.clone())
+        let mut view = view::View::new(interval.clone(), output_width)
             // Set interval on view.header
             .set_interval(interval)
             .set_tab_size(tab_size)

src/view.rs

@@ -39,6 +39,7 @@ use crate::DEFAULT_TAB_SIZE;
 pub struct View {
     after_command: String,
     interval: Interval,
+    output_width: Arc<RwLock<Option<usize>>>,
     tab_size: u16,
     limit: u32,
     keymap: Keymap,
@@ -60,10 +61,11 @@ pub struct View {
 
 ///
 impl View {
-    pub fn new(interval: Interval) -> Self {
+    pub fn new(interval: Interval, output_width: Arc<RwLock<Option<usize>>>) -> Self {
         Self {
             after_command: "".to_string(),
             interval,
+            output_width,
             tab_size: DEFAULT_TAB_SIZE,
             limit: 0,
             keymap: default_keymap(),
@@ -207,7 +209,7 @@ impl View {
         }
 
         // Create App
-        let mut app = App::new(tx, rx, self.interval.clone());
+        let mut app = App::new(tx, rx, self.interval.clone(), self.output_width.clone());
 
         // set keymap
         app.set_keymap(self.keymap.clone());

src/watch.rs

@@ -111,6 +111,7 @@ impl<'a> WatchArea<'a> {
     }
 
     ///
+    // TODO: Rename to get_area_height?
     pub fn get_area_size(&mut self) -> i16 {
         let height = self.area.height as i16;