Fix Highlighter::highlight_char

Introduce `CmdKind` parameter to make the distinction between
edits vs cursor moves vs final refresh

examples/example.rs

@@ -2,7 +2,7 @@ use std::borrow::Cow::{self, Borrowed, Owned};
 
 use rustyline::completion::FilenameCompleter;
 use rustyline::error::ReadlineError;
-use rustyline::highlight::{Highlighter, MatchingBracketHighlighter};
+use rustyline::highlight::{CmdKind, Highlighter, MatchingBracketHighlighter};
 use rustyline::hint::HistoryHinter;
 use rustyline::validate::MatchingBracketValidator;
 use rustyline::{Cmd, CompletionType, Config, EditMode, Editor, KeyEvent};
@@ -41,8 +41,8 @@ impl Highlighter for MyHelper {
         self.highlighter.highlight(line, pos)
     }
 
-    fn highlight_char(&self, line: &str, pos: usize, forced: bool) -> bool {
-        self.highlighter.highlight_char(line, pos, forced)
+    fn highlight_char(&self, line: &str, pos: usize, kind: CmdKind) -> bool {
+        self.highlighter.highlight_char(line, pos, kind)
     }
 }
 

examples/read_password.rs

@@ -1,7 +1,7 @@
 use std::borrow::Cow::{self, Borrowed, Owned};
 
 use rustyline::config::Configurer;
-use rustyline::highlight::Highlighter;
+use rustyline::highlight::{CmdKind, Highlighter};
 use rustyline::{ColorMode, Editor, Result};
 use rustyline::{Completer, Helper, Hinter, Validator};
 
@@ -20,12 +20,16 @@ impl Highlighter for MaskingHighlighter {
         }
     }
 
-    fn highlight_char(&self, _line: &str, _pos: usize, _forced: bool) -> bool {
-        self.masking
+    fn highlight_char(&self, _line: &str, _pos: usize, kind: CmdKind) -> bool {
+        match kind {
+            CmdKind::MoveCursor => false,
+            _ => self.masking,
+        }
     }
 }
 
 fn main() -> Result<()> {
+    env_logger::init();
     println!("This is just a hack. Reading passwords securely requires more than that.");
     let h = MaskingHighlighter { masking: false };
     let mut rl = Editor::new()?;

rustyline-derive/src/lib.rs

@@ -126,8 +126,8 @@ pub fn highlighter_macro_derive(input: TokenStream) -> TokenStream {
                     ::rustyline::highlight::Highlighter::highlight_candidate(&self.#field_name_or_index, candidate, completion)
                 }
 
-                fn highlight_char(&self, line: &str, pos: usize, forced: bool) -> bool {
-                    ::rustyline::highlight::Highlighter::highlight_char(&self.#field_name_or_index, line, pos, forced)
+                fn highlight_char(&self, line: &str, pos: usize, kind: ::rustyline::highlight::CmdKind) -> bool {
+                    ::rustyline::highlight::Highlighter::highlight_char(&self.#field_name_or_index, line, pos, kind)
                 }
             }
         }

src/command.rs

@@ -2,6 +2,7 @@ use crate::complete_hint_line;
 use crate::config::Config;
 use crate::edit::State;
 use crate::error;
+use crate::highlight::CmdKind;
 use crate::history::SearchDirection;
 use crate::keymap::{Anchor, At, Cmd, Movement, Word};
 use crate::keymap::{InputState, Refresher};
@@ -28,9 +29,7 @@ pub fn execute<H: Helper>(
             if s.has_hint() || !s.is_default_prompt() || s.highlight_char {
                 // Force a refresh without hints to leave the previous
                 // line as the user typed it after a newline.
-                s.forced_refresh = true;
-                s.refresh_line_with_msg(None)?;
-                s.forced_refresh = false;
+                s.refresh_line_with_msg(None, CmdKind::ForcedRefresh)?;
             }
         }
         _ => {}
@@ -190,7 +189,7 @@ pub fn execute<H: Helper>(
         }
         Cmd::Move(Movement::EndOfBuffer) => {
             // Move to the end of the buffer.
-            s.edit_move_buffer_end()?;
+            s.edit_move_buffer_end(CmdKind::MoveCursor)?;
         }
         Cmd::DowncaseWord => {
             // lowercase word after point

src/edit.rs

@@ -7,7 +7,7 @@ use unicode_width::UnicodeWidthChar;
 
 use super::{Context, Helper, Result};
 use crate::error::ReadlineError;
-use crate::highlight::Highlighter;
+use crate::highlight::{CmdKind, Highlighter};
 use crate::hint::Hint;
 use crate::history::SearchDirection;
 use crate::keymap::{Anchor, At, CharSearch, Cmd, Movement, RepeatCount, Word};
@@ -36,7 +36,6 @@ pub struct State<'out, 'prompt, H: Helper> {
     pub ctx: Context<'out>,          // Give access to history for `hinter`
     pub hint: Option<Box<dyn Hint>>, // last hint displayed
     pub highlight_char: bool,        // `true` if a char has been highlighted
-    pub forced_refresh: bool,        // `true` if line is redraw without hint or highlight_char
 }
 
 enum Info<'m> {
@@ -66,7 +65,6 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
             ctx,
             hint: None,
             highlight_char: false,
-            forced_refresh: false,
         }
     }
 
@@ -122,15 +120,15 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
         );
     }
 
-    pub fn move_cursor(&mut self) -> Result<()> {
+    pub fn move_cursor(&mut self, kind: CmdKind) -> Result<()> {
         // calculate the desired position of the cursor
         let cursor = self
             .out
             .calculate_position(&self.line[..self.line.pos()], self.prompt_size);
         if self.layout.cursor == cursor {
             return Ok(());
         }
-        if self.highlight_char() {
+        if self.highlight_char(kind) {
             let prompt_size = self.prompt_size;
             self.refresh(self.prompt, prompt_size, true, Info::NoHint)?;
         } else {
@@ -205,10 +203,9 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
         }
     }
 
-    fn highlight_char(&mut self) -> bool {
+    fn highlight_char(&mut self, kind: CmdKind) -> bool {
         if let Some(highlighter) = self.highlighter() {
-            let highlight_char =
-                highlighter.highlight_char(&self.line, self.line.pos(), self.forced_refresh);
+            let highlight_char = highlighter.highlight_char(&self.line, self.line.pos(), kind);
             if highlight_char {
                 self.highlight_char = true;
                 true
@@ -240,12 +237,12 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
                     if corrected || self.has_hint() || msg.is_some() {
                         // Force a refresh without hints to leave the previous
                         // line as the user typed it after a newline.
-                        self.refresh_line_with_msg(msg.as_deref())?;
+                        self.refresh_line_with_msg(msg.as_deref(), CmdKind::ForcedRefresh)?;
                     }
                 }
                 ValidationResult::Invalid(ref msg) => {
                     if corrected || self.has_hint() || msg.is_some() {
-                        self.refresh_line_with_msg(msg.as_deref())?;
+                        self.refresh_line_with_msg(msg.as_deref(), CmdKind::Other)?;
                     }
                 }
             }
@@ -266,21 +263,21 @@ impl<'out, 'prompt, H: Helper> Refresher for State<'out, 'prompt, H> {
     fn refresh_line(&mut self) -> Result<()> {
         let prompt_size = self.prompt_size;
         self.hint();
-        self.highlight_char();
+        self.highlight_char(CmdKind::Other);
         self.refresh(self.prompt, prompt_size, true, Info::Hint)
     }
 
-    fn refresh_line_with_msg(&mut self, msg: Option<&str>) -> Result<()> {
+    fn refresh_line_with_msg(&mut self, msg: Option<&str>, kind: CmdKind) -> Result<()> {
         let prompt_size = self.prompt_size;
         self.hint = None;
-        self.highlight_char();
+        self.highlight_char(kind);
         self.refresh(self.prompt, prompt_size, true, Info::Msg(msg))
     }
 
     fn refresh_prompt_and_line(&mut self, prompt: &str) -> Result<()> {
         let prompt_size = self.out.calculate_position(prompt, Position::default());
         self.hint();
-        self.highlight_char();
+        self.highlight_char(CmdKind::Other);
         self.refresh(prompt, prompt_size, false, Info::Hint)
     }
 
@@ -361,7 +358,7 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
                     && width != 0 // Ctrl-V + \t or \n ...
                     && self.layout.cursor.col + width < self.out.get_columns()
                     && (self.hint.is_none() && no_previous_hint) // TODO refresh only current line
-                    && !self.highlight_char()
+                    && !self.highlight_char(CmdKind::Other)
                 {
                     // Avoid a full update of the line in the trivial case.
                     self.layout.cursor.col += width;
@@ -454,7 +451,7 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
     /// Move cursor on the left.
     pub fn edit_move_backward(&mut self, n: RepeatCount) -> Result<()> {
         if self.line.move_backward(n) {
-            self.move_cursor()
+            self.move_cursor(CmdKind::MoveCursor)
         } else {
             Ok(())
         }
@@ -463,7 +460,7 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
     /// Move cursor on the right.
     pub fn edit_move_forward(&mut self, n: RepeatCount) -> Result<()> {
         if self.line.move_forward(n) {
-            self.move_cursor()
+            self.move_cursor(CmdKind::MoveCursor)
         } else {
             Ok(())
         }
@@ -472,7 +469,7 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
     /// Move cursor to the start of the line.
     pub fn edit_move_home(&mut self) -> Result<()> {
         if self.line.move_home() {
-            self.move_cursor()
+            self.move_cursor(CmdKind::MoveCursor)
         } else {
             Ok(())
         }
@@ -481,7 +478,7 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
     /// Move cursor to the end of the line.
     pub fn edit_move_end(&mut self) -> Result<()> {
         if self.line.move_end() {
-            self.move_cursor()
+            self.move_cursor(CmdKind::MoveCursor)
         } else {
             Ok(())
         }
@@ -490,16 +487,16 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
     /// Move cursor to the start of the buffer.
     pub fn edit_move_buffer_start(&mut self) -> Result<()> {
         if self.line.move_buffer_start() {
-            self.move_cursor()
+            self.move_cursor(CmdKind::MoveCursor)
         } else {
             Ok(())
         }
     }
 
     /// Move cursor to the end of the buffer.
-    pub fn edit_move_buffer_end(&mut self) -> Result<()> {
+    pub fn edit_move_buffer_end(&mut self, kind: CmdKind) -> Result<()> {
         if self.line.move_buffer_end() {
-            self.move_cursor()
+            self.move_cursor(kind)
         } else {
             Ok(())
         }
@@ -565,15 +562,15 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
 
     pub fn edit_move_to_prev_word(&mut self, word_def: Word, n: RepeatCount) -> Result<()> {
         if self.line.move_to_prev_word(word_def, n) {
-            self.move_cursor()
+            self.move_cursor(CmdKind::MoveCursor)
         } else {
             Ok(())
         }
     }
 
     pub fn edit_move_to_next_word(&mut self, at: At, word_def: Word, n: RepeatCount) -> Result<()> {
         if self.line.move_to_next_word(at, word_def, n) {
-            self.move_cursor()
+            self.move_cursor(CmdKind::MoveCursor)
         } else {
             Ok(())
         }
@@ -582,7 +579,7 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
     /// Moves the cursor to the same column in the line above
     pub fn edit_move_line_up(&mut self, n: RepeatCount) -> Result<bool> {
         if self.line.move_to_line_up(n) {
-            self.move_cursor()?;
+            self.move_cursor(CmdKind::MoveCursor)?;
             Ok(true)
         } else {
             Ok(false)
@@ -592,7 +589,7 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
     /// Moves the cursor to the same column in the line above
     pub fn edit_move_line_down(&mut self, n: RepeatCount) -> Result<bool> {
         if self.line.move_to_line_down(n) {
-            self.move_cursor()?;
+            self.move_cursor(CmdKind::MoveCursor)?;
             Ok(true)
         } else {
             Ok(false)
@@ -601,7 +598,7 @@ impl<'out, 'prompt, H: Helper> State<'out, 'prompt, H> {
 
     pub fn edit_move_to(&mut self, cs: CharSearch, n: RepeatCount) -> Result<()> {
         if self.line.move_to(cs, n) {
-            self.move_cursor()
+            self.move_cursor(CmdKind::MoveCursor)
         } else {
             Ok(())
         }
@@ -765,7 +762,6 @@ pub fn init_state<'out, H: Helper>(
         ctx: Context::new(history),
         hint: Some(Box::new("hint".to_owned())),
         highlight_char: false,
-        forced_refresh: false,
     }
 }
 

src/highlight.rs

@@ -4,6 +4,18 @@ use crate::config::CompletionType;
 use std::borrow::Cow::{self, Borrowed, Owned};
 use std::cell::Cell;
 
+/// Describe which kind of action has been triggering the call to `Highlighter`.
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum CmdKind {
+    /// Cursor moved
+    MoveCursor,
+    /// Other action
+    Other,
+    /// Forced / final refresh (no auto-suggestion / hint, no matching bracket
+    /// highlighted, ...)
+    ForcedRefresh,
+}
+
 /// Syntax highlighter with [ANSI color](https://en.wikipedia.org/wiki/ANSI_escape_code#SGR_(Select_Graphic_Rendition)_parameters).
 ///
 /// Currently, the highlighted version *must* have the same display width as
@@ -47,13 +59,11 @@ pub trait Highlighter {
     }
     /// Tells if `line` needs to be highlighted when a specific char is typed or
     /// when cursor is moved under a specific char.
-    /// `forced` flag is `true` mainly when user presses Enter (i.e. transient
-    /// vs final highlight).
     ///
     /// Used to optimize refresh when a character is inserted or the cursor is
     /// moved.
-    fn highlight_char(&self, line: &str, pos: usize, forced: bool) -> bool {
-        let _ = (line, pos, forced);
+    fn highlight_char(&self, line: &str, pos: usize, kind: CmdKind) -> bool {
+        let _ = (line, pos, kind);
         false
     }
 }
@@ -85,8 +95,8 @@ impl<'r, H: ?Sized + Highlighter> Highlighter for &'r H {
         (**self).highlight_candidate(candidate, completion)
     }
 
-    fn highlight_char(&self, line: &str, pos: usize, forced: bool) -> bool {
-        (**self).highlight_char(line, pos, forced)
+    fn highlight_char(&self, line: &str, pos: usize, kind: CmdKind) -> bool {
+        (**self).highlight_char(line, pos, kind)
     }
 }
 
@@ -124,8 +134,8 @@ impl Highlighter for MatchingBracketHighlighter {
         Borrowed(line)
     }
 
-    fn highlight_char(&self, line: &str, pos: usize, forced: bool) -> bool {
-        if forced {
+    fn highlight_char(&self, line: &str, pos: usize, kind: CmdKind) -> bool {
+        if kind == CmdKind::ForcedRefresh {
             self.bracket.set(None);
             return false;
         }

src/keymap.rs

@@ -2,6 +2,7 @@
 use log::debug;
 
 use super::Result;
+use crate::highlight::CmdKind;
 use crate::keys::{KeyCode as K, KeyEvent, KeyEvent as E, Modifiers as M};
 use crate::tty::{self, RawReader, Term, Terminal};
 use crate::{Config, EditMode};
@@ -374,7 +375,7 @@ pub trait Refresher {
     /// cursor position, and number of columns of the terminal.
     fn refresh_line(&mut self) -> Result<()>;
     /// Same as [`refresh_line`] with a specific message instead of hint
-    fn refresh_line_with_msg(&mut self, msg: Option<&str>) -> Result<()>;
+    fn refresh_line_with_msg(&mut self, msg: Option<&str>, kind: CmdKind) -> Result<()>;
     /// Same as `refresh_line` but with a dynamic prompt.
     fn refresh_prompt_and_line(&mut self, prompt: &str) -> Result<()>;
     /// Vi only, switch to insert mode.

src/lib.rs

@@ -59,7 +59,7 @@ use crate::completion::{longest_common_prefix, Candidate, Completer};
 pub use crate::config::{Behavior, ColorMode, CompletionType, Config, EditMode, HistoryDuplicates};
 use crate::edit::State;
 use crate::error::ReadlineError;
-use crate::highlight::Highlighter;
+use crate::highlight::{CmdKind, Highlighter};
 use crate::hint::Hinter;
 use crate::history::{DefaultHistory, History, SearchDirection};
 pub use crate::keymap::{Anchor, At, CharSearch, Cmd, InputMode, Movement, RepeatCount, Word};
@@ -790,9 +790,7 @@ impl<H: Helper, I: History> Editor<H, I> {
 
         // Move to end, in case cursor was in the middle of the line, so that
         // next thing application prints goes after the input
-        s.forced_refresh = true;
-        s.edit_move_buffer_end()?;
-        s.forced_refresh = false;
+        s.edit_move_buffer_end(CmdKind::ForcedRefresh)?;
 
         if cfg!(windows) {
             let _ = original_mode; // silent warning