Fix yet another missing history bounds check

src/reader/esc_parse/mod.rs

@@ -105,6 +105,10 @@ impl SequenceState {
             self.out_buf.push(InputChar::Backspace);
             Result::Ok(())
         }
+        else if chr == 0x04 {
+            self.out_buf.push(InputChar::EoT);
+            Result::Ok(())
+        }
         // Unrecognized
         else {
             Result::Err(AcceptError::Unimplemented(chr))

src/reader/mod.rs

@@ -1,6 +1,6 @@
 #![allow(unused)]
 
-use std::mem::MaybeUninit;
+use std::{io::Read, mem::MaybeUninit};
 
 use crate::reader::esc_parse::{InputChar, bell, hide_cursor, show_cursor};
 
@@ -24,7 +24,8 @@ pub enum InitTTYError {
 
 #[derive(Debug)]
 pub enum ReadError {
-    EscapeError(esc_parse::AcceptError)
+    EscapeError(esc_parse::AcceptError),
+    Exited,
 }
 
 #[derive(Debug)]
@@ -35,6 +36,7 @@ pub enum EditCommand {
     CursorBack,
     CursorForward,
     DeleteBack,
+    Exit,
 }
 
 macro_rules! edit_cmd {
@@ -82,10 +84,10 @@ impl ReaderState {
         self.redraw();
     }
 
-    fn current_hist(&mut self) -> String {
+    fn current_hist(&mut self) -> Option<String> {
         let i: usize = self.history_inx.unwrap();
         let line = self.history.get(self.history.len().saturating_sub(i+1));
-        return line.unwrap().to_string();
+        return line.map(|s| s.to_string());
     }
 
     fn set_current_hist(&mut self, str: String) {
@@ -95,7 +97,7 @@ impl ReaderState {
     }
 
     fn insert_at_cursor_hist(&mut self, txt: String) {
-        let mut line = self.current_hist();
+        let mut line = self.current_hist().expect("Trying to modify a non-existent history entry");
         line.insert_str(self.cursor, txt.as_str());
         self.history_reset();
         self.set_line(line.clone());
@@ -145,6 +147,9 @@ impl ReaderState {
                         if chr == InputChar::Backspace {
                             return edit_cmd!(DeleteBack);
                         }
+                        if chr == InputChar::EoT {
+                            return edit_cmd!(Exit);
+                        }
                     }
                 }
             }
@@ -172,6 +177,7 @@ impl ReaderState {
     pub fn read_line(&mut self) -> Result<String, ReadError> {
         use EditCommand::*;
         loop {
+            self.set_prompt(format!("{:?}> ", self.history_inx));
             let cmd = self.input_line();
             if cmd.is_err() {
                 return Err(cmd.err().unwrap());
@@ -197,7 +203,8 @@ impl ReaderState {
                 },
                 HistoryNext => {
                     self.history_front();
-                }
+                },
+                Exit => return Err(ReadError::Exited)
             }
         }
     }
@@ -226,7 +233,7 @@ impl ReaderState {
     pub fn history_back(&mut self) {
         let h = self.history.clone();
         let mut i = self.history_inx;
-        if i.map_or(false, |v| v+1 == h.len()) {
+        if i.map_or(h.len() == 0, |v| v+1 == h.len()) {
             bell();
             return;
         }
@@ -239,7 +246,12 @@ impl ReaderState {
         self.history_inx = i;
         let i: usize = i.unwrap();
         let line = h.get(h.len().saturating_sub(i+1));
-        self.set_line(line.unwrap().to_string());
+        if line.is_some() {
+            self.set_line(line.unwrap().to_string());
+        } else {
+            bell();
+            self.redraw();
+        }
     }
 
     fn saved_restore(&mut self) {
@@ -262,7 +274,12 @@ impl ReaderState {
         }
         let i = i.unwrap();
         let line = h.get(h.len().saturating_sub(i+1));
-        self.set_line(line.unwrap().to_string());
+        if line.is_some() {
+            self.set_line(line.unwrap().to_string());
+        } else {
+            bell();
+            self.redraw();
+        }
     }
 
     pub fn move_left(&mut self) {
@@ -304,7 +321,7 @@ impl ReaderState {
     pub fn backspace(&mut self) {
         if self.history_inx.is_some() {
             if self.cursor > 0 {
-                let mut line = self.current_hist();
+                let mut line = self.current_hist().expect("Trying to modify a non-existent history entry");
                 line.remove(self.cursor-1);
                 self.move_left();
                 self.history_reset();