change 'password' to more generic 'mask'. Fix tab behavior

examples/password.rs

@@ -21,8 +21,8 @@ fn main() -> io::Result<()> {
 
     let mut textarea = TextArea::default();
     textarea.set_cursor_line_style(Style::default());
-    textarea.set_password_mode(true);
-    textarea.set_placeholder_text("please enter your password");
+    textarea.set_mask_char('\u{2022}'); //U+2022 BULLET (•)
+    textarea.set_placeholder_text("Please enter your password");
     let layout =
         Layout::default().constraints([Constraint::Length(3), Constraint::Min(1)].as_slice());
     textarea.set_style(Style::default().fg(Color::LightGreen));

src/highlight.rs

@@ -48,28 +48,39 @@ impl Boundary {
     }
 }
 
-fn replace_tabs(s: &str, tab_len: u8, mask: bool) -> Cow<'_, str> {
-    let tab = spaces(tab_len);
-    let mut buf = String::new();
-    for (i, c) in s.char_indices() {
-        if buf.is_empty() {
-            if c == '\t' {
-                buf.reserve(s.len());
-                buf.push_str(&s[..i]);
-                buf.push_str(tab);
-            }
-        } else if c == '\t' {
-            buf.push_str(tab);
-        } else {
-            buf.push(c);
+fn prepare_line(s: &str, tab_len: u8, mask: Option<char>) -> Cow<'_, str> {
+    // two tasks performed here
+    // - mask out chars if mask is Some
+    // - replace hard tabs by the correct number of spaces
+    //   (soft tabs were done earlier in 'insert_tab')
+    match mask {
+        Some(ch) => {
+            // no tab processing in the mask case
+            return Cow::Owned(s.chars().map(|_| ch).collect());
         }
-    }
-    match (buf.is_empty(), mask) {
-        (true, true) => Cow::Owned(s.chars().map(|_| '*').collect()),
-        (true, false) => Cow::Borrowed(s),
-        (false, true) => Cow::Owned(buf.chars().map(|_| '*').collect()),
-        (false, false) => Cow::Owned(buf),
-    }
+        None => {
+            let tab = spaces(tab_len);
+            let mut buf = String::new();
+            for (i, c) in s.char_indices() {
+                if buf.is_empty() {
+                    if c == '\t' {
+                        buf.reserve(s.len());
+                        buf.push_str(&s[..i]);
+                        buf.push_str(tab);
+                    }
+                } else if c == '\t' {
+                    buf.push_str(tab);
+                } else {
+                    buf.push(c);
+                }
+            }
+            if !buf.is_empty() {
+                return Cow::Owned(buf);
+            }
+        }
+    };
+    // drop through in the case of no mask and no tabs
+    return Cow::Borrowed(s);
 }
 
 pub struct LineHighlighter<'a> {
@@ -122,7 +133,7 @@ impl<'a> LineHighlighter<'a> {
         }
     }
 
-    pub fn into_spans(self, mask: bool) -> Spans<'a> {
+    pub fn into_spans(self, mask: Option<char>) -> Spans<'a> {
         let Self {
             line,
             mut spans,
@@ -134,7 +145,7 @@ impl<'a> LineHighlighter<'a> {
         } = self;
 
         if boundaries.is_empty() {
-            spans.push(Span::styled(replace_tabs(line, tab_len, mask), style_begin));
+            spans.push(Span::styled(prepare_line(line, tab_len, mask), style_begin));
             if cursor_at_end {
                 spans.push(Span::styled(" ", cursor_style));
             }
@@ -155,7 +166,7 @@ impl<'a> LineHighlighter<'a> {
             if let Some((next_boundary, end)) = boundaries.next() {
                 if start < end {
                     spans.push(Span::styled(
-                        replace_tabs(&line[start..end], tab_len, mask),
+                        prepare_line(&line[start..end], tab_len, mask),
                         style,
                     ));
                 }
@@ -170,7 +181,7 @@ impl<'a> LineHighlighter<'a> {
             } else {
                 if start != line.len() {
                     spans.push(Span::styled(
-                        replace_tabs(&line[start..], tab_len, mask),
+                        prepare_line(&line[start..], tab_len, mask),
                         style,
                     ));
                 }

src/textarea.rs

@@ -63,7 +63,7 @@ pub struct TextArea<'a> {
     alignment: Alignment,
     pub(crate) placeholder: String,
     pub(crate) placeholder_style: Style,
-    password_mode: bool,
+    mask: Option<char>,
 }
 
 /// Convert any iterator whose elements can be converted into [`String`] into [`TextArea`]. Each [`String`] element is
@@ -163,7 +163,7 @@ impl<'a> TextArea<'a> {
             alignment: Alignment::Left,
             placeholder: String::new(),
             placeholder_style: Style::default().fg(Color::DarkGray),
-            password_mode: false,
+            mask: None,
         }
     }
 
@@ -1007,7 +1007,7 @@ impl<'a> TextArea<'a> {
             hl.search(matches, self.search.style);
         }
 
-        hl.into_spans(self.password_mode)
+        hl.into_spans(self.mask)
     }
 
     /// Build a tui-rs widget to render the current state of the textarea. The widget instance returned from this
@@ -1306,11 +1306,18 @@ impl<'a> TextArea<'a> {
         }
     }
 
-    /// Sets a flag indicating if the text should be masked with * characters
+    /// Specifies that the text should be masked with the specified character
     ///
-    pub fn set_password_mode(&mut self, value: bool) {
-        self.password_mode = value;
+    pub fn set_mask_char(&mut self, mask: char) {
+        self.mask = Some(mask);
     }
+
+    /// Clear the previously set masking character
+    ///
+    pub fn clear_mask_char(&mut self) {
+        self.mask = None;
+    }
+
     /// Set the style of cursor. By default, a cursor is rendered in the reversed color. Setting the same style as
     /// cursor line hides a cursor.
     /// ```