remove parser.screen_mut

it's easier to reason about if you are only able to get an immutable
reference to the internal screen. this also required changing the api
for bells.

8 files changed, 98 insertions, 87 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bd0dc9f..c268b6c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,9 +8,19 @@
 * `Default` impl for `Parser` which creates an 80x24 terminal with no
   scrollback.
 
+### Removed
+
+* `Parser::screen_mut` (and the `pub` `&mut self` methods on `Screen`). The few
+  things you can do to change the screen state directly are now exposed as
+  methods on `Parser` itself.
+
 ### Changed
 
 * `Cell::contents` now returns a `String` instead of a `&str`.
+* `Screen::check_audible_bell` and `Screen::check_visual_bell` have been
+  replaced with `Screen::audible_bell_count` and `Screen::visual_bell_count`.
+  You should keep track of the "since the last method call" state yourself
+  instead of having the screen track it for you.
 
 ### Fixed
 
diff --git a/src/parser.rs b/src/parser.rs
index 07ee7c9..613e18e 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -26,17 +26,31 @@ impl Parser {
         }
     }
 
+    /// Resizes the terminal.
+    pub fn set_size(&mut self, rows: u16, cols: u16) {
+        self.screen.set_size(rows, cols);
+    }
+
+    /// Scrolls to the given position in the scrollback.
+    ///
+    /// This position indicates the offset from the top of the screen, and
+    /// should be `0` to put the normal screen in view.
+    ///
+    /// This affects the return values of methods called on `parser.screen()`:
+    /// for instance, `parser.screen().cell(0, 0)` will return the top left
+    /// corner of the screen after taking the scrollback offset into account.
+    /// It does not affect `parser.process()` at all.
+    ///
+    /// The value given will be clamped to the actual size of the scrollback.
+    pub fn set_scrollback(&mut self, rows: usize) {
+        self.screen.set_scrollback(rows);
+    }
+
     /// Returns a reference to a `Screen` object containing the terminal
     /// state.
     pub fn screen(&self) -> &crate::screen::Screen {
         &self.screen
     }
-
-    /// Returns a mutable reference to a `Screen` object containing the
-    /// terminal state.
-    pub fn screen_mut(&mut self) -> &mut crate::screen::Screen {
-        &mut self.screen
-    }
 }
 
 impl Default for Parser {
diff --git a/src/screen.rs b/src/screen.rs
index 36a47c4..c2eaf0e 100644
--- a/src/screen.rs
+++ b/src/screen.rs
@@ -5,12 +5,6 @@ use unicode_width::UnicodeWidthChar as _;
 const DEFAULT_MULTI_PARAMS: &[i64] = &[0];
 
 #[derive(enumset::EnumSetType, Debug)]
-enum Output {
-    AudibleBell,
-    VisualBell,
-}
-
-#[derive(enumset::EnumSetType, Debug)]
 enum Mode {
     ApplicationKeypad,
     ApplicationCursor,
@@ -84,10 +78,12 @@ pub struct Screen {
     title: String,
     icon_name: String,
 
-    outputs: enumset::EnumSet<Output>,
     modes: enumset::EnumSet<Mode>,
     mouse_protocol_mode: MouseProtocolMode,
     mouse_protocol_encoding: MouseProtocolEncoding,
+
+    audible_bell_count: usize,
+    visual_bell_count: usize,
 }
 
 impl Screen {
@@ -105,15 +101,16 @@ impl Screen {
             title: String::default(),
             icon_name: String::default(),
 
-            outputs: enumset::EnumSet::default(),
             modes: enumset::EnumSet::default(),
             mouse_protocol_mode: MouseProtocolMode::default(),
             mouse_protocol_encoding: MouseProtocolEncoding::default(),
+
+            audible_bell_count: 0,
+            visual_bell_count: 0,
         }
     }
 
-    /// Resizes the terminal.
-    pub fn set_size(&mut self, rows: u16, cols: u16) {
+    pub(crate) fn set_size(&mut self, rows: u16, cols: u16) {
         self.grid.set_size(crate::grid::Size { rows, cols });
         self.alternate_grid
             .set_size(crate::grid::Size { rows, cols });
@@ -135,18 +132,7 @@ impl Screen {
         self.grid().scrollback()
     }
 
-    /// Scrolls to the given position in the scrollback.
-    ///
-    /// This position indicates the offset from the top of the screen, and
-    /// should be `0` to put the normal screen in view.
-    ///
-    /// This affects the return values of methods called on `parser.screen()`:
-    /// for instance, `parser.screen().cell(0, 0)` will return the top left
-    /// corner of the screen after taking the scrollback offset into account.
-    /// It does not affect `parser.process()` at all.
-    ///
-    /// The value given will be clamped to the actual size of the scrollback.
-    pub fn set_scrollback(&mut self, rows: usize) {
+    pub(crate) fn set_scrollback(&mut self, rows: usize) {
         self.grid_mut().set_scrollback(rows);
     }
 
@@ -321,16 +307,20 @@ impl Screen {
         &self.icon_name
     }
 
-    /// Returns whether an audible bell has occurred since the last time this
-    /// method was called.
-    pub fn check_audible_bell(&mut self) -> bool {
-        self.check_output(Output::AudibleBell)
+    /// Returns the total number of audible bells seen so far.
+    ///
+    /// Typically you would store this number after each call to `process`,
+    /// and trigger an audible bell whenever it changes.
+    pub fn audible_bell_count(&self) -> usize {
+        self.audible_bell_count
     }
 
-    /// Returns whether an visual bell has occurred since the last time this
-    /// method was called.
-    pub fn check_visual_bell(&mut self) -> bool {
-        self.check_output(Output::VisualBell)
+    /// Returns the total number of visual bells seen so far.
+    ///
+    /// Typically you would store this number after each call to `process`,
+    /// and trigger an visual bell whenever it changes.
+    pub fn visual_bell_count(&self) -> usize {
+        self.visual_bell_count
     }
 
     /// Returns whether the terminal should be in application keypad mode.
@@ -413,20 +403,6 @@ impl Screen {
         self.attrs = self.saved_attrs;
     }
 
-    fn set_output(&mut self, output: Output) {
-        self.outputs.insert(output);
-    }
-
-    fn clear_output(&mut self, output: Output) {
-        self.outputs.remove(output);
-    }
-
-    fn check_output(&mut self, output: Output) -> bool {
-        let ret = self.outputs.contains(output);
-        self.clear_output(output);
-        ret
-    }
-
     fn set_mode(&mut self, mode: Mode) {
         self.modes.insert(mode);
     }
@@ -523,7 +499,7 @@ impl Screen {
     // control codes
 
     fn bel(&mut self) {
-        self.set_output(Output::AudibleBell);
+        self.audible_bell_count += 1;
     }
 
     fn bs(&mut self) {
@@ -579,20 +555,22 @@ impl Screen {
 
     // ESC c
     fn ris(&mut self) {
-        let outputs = self.outputs;
         let title = self.title.clone();
         let icon_name = self.icon_name.clone();
+        let audible_bell_count = self.audible_bell_count;
+        let visual_bell_count = self.visual_bell_count;
 
         *self = Self::new(self.grid.size(), self.grid.scrollback_len());
 
-        self.outputs = outputs;
         self.title = title;
         self.icon_name = icon_name;
+        self.audible_bell_count = audible_bell_count;
+        self.visual_bell_count = visual_bell_count;
     }
 
     // ESC g
     fn vb(&mut self) {
-        self.set_output(Output::VisualBell);
+        self.visual_bell_count += 1;
     }
 
     // csi codes
diff --git a/tests/basic.rs b/tests/basic.rs
index 0f2da75..33a272d 100644
--- a/tests/basic.rs
+++ b/tests/basic.rs
@@ -20,18 +20,18 @@ fn set_size() {
     assert_eq!(parser.screen().size(), (24, 80));
     assert_eq!(parser.screen().cursor_position(), (0, 0));
 
-    parser.screen_mut().set_size(34, 8);
+    parser.set_size(34, 8);
     assert_eq!(parser.screen().size(), (34, 8));
     assert_eq!(parser.screen().cursor_position(), (0, 0));
 
     parser.process(b"\x1b[30;5H");
     assert_eq!(parser.screen().cursor_position(), (29, 4));
 
-    parser.screen_mut().set_size(24, 80);
+    parser.set_size(24, 80);
     assert_eq!(parser.screen().size(), (24, 80));
     assert_eq!(parser.screen().cursor_position(), (23, 4));
 
-    parser.screen_mut().set_size(34, 8);
+    parser.set_size(34, 8);
     assert_eq!(parser.screen().size(), (34, 8));
     assert_eq!(parser.screen().cursor_position(), (23, 4));
 
@@ -39,7 +39,7 @@ fn set_size() {
     assert_eq!(parser.screen().size(), (34, 8));
     assert_eq!(parser.screen().cursor_position(), (0, 0));
 
-    parser.screen_mut().set_size(24, 80);
+    parser.set_size(24, 80);
     assert_eq!(parser.screen().size(), (24, 80));
     assert_eq!(parser.screen().cursor_position(), (0, 0));
 
@@ -47,14 +47,14 @@ fn set_size() {
     assert_eq!(parser.screen().size(), (24, 80));
     assert_eq!(parser.screen().cursor_position(), (23, 4));
 
-    parser.screen_mut().set_size(34, 8);
+    parser.set_size(34, 8);
     parser.process(b"\x1bc01234567890123456789");
     assert_eq!(parser.screen().contents(), "01234567890123456789");
 
-    parser.screen_mut().set_size(24, 80);
+    parser.set_size(24, 80);
     assert_eq!(parser.screen().contents(), "01234567\n89012345\n6789");
 
-    parser.screen_mut().set_size(34, 8);
+    parser.set_size(34, 8);
     assert_eq!(parser.screen().contents(), "01234567\n89012345\n6789");
 }
 
diff --git a/tests/control.rs b/tests/control.rs
index 9392b5e..aba6915 100644
--- a/tests/control.rs
+++ b/tests/control.rs
@@ -3,12 +3,17 @@
 #[test]
 fn bel() {
     let mut parser = vt100::Parser::default();
+    assert_eq!(parser.screen().audible_bell_count(), 0);
 
-    assert!(!parser.screen_mut().check_audible_bell());
+    parser.process(b"\x07");
+    assert_eq!(parser.screen().audible_bell_count(), 1);
+    assert_eq!(parser.screen().audible_bell_count(), 1);
 
     parser.process(b"\x07");
-    assert!(parser.screen_mut().check_audible_bell());
-    assert!(!parser.screen_mut().check_audible_bell());
+    assert_eq!(parser.screen().audible_bell_count(), 2);
+
+    parser.process(b"\x07\x07\x07");
+    assert_eq!(parser.screen().audible_bell_count(), 5);
 }
 
 #[test]
diff --git a/tests/escape.rs b/tests/escape.rs
index 43eb666..e08a402 100644
--- a/tests/escape.rs
+++ b/tests/escape.rs
@@ -40,8 +40,8 @@ fn ris() {
     assert_eq!(parser.screen().title(), "");
     assert_eq!(parser.screen().icon_name(), "");
 
-    assert!(!parser.screen_mut().check_visual_bell());
-    assert!(!parser.screen_mut().check_audible_bell());
+    assert_eq!(parser.screen().audible_bell_count(), 0);
+    assert_eq!(parser.screen().visual_bell_count(), 0);
     assert!(!parser.screen().application_keypad());
     assert!(!parser.screen().application_cursor());
     assert!(!parser.screen().hide_cursor());
@@ -72,8 +72,8 @@ fn ris() {
     assert_eq!(parser.screen().title(), "window title");
     assert_eq!(parser.screen().icon_name(), "window icon name");
 
-    assert!(parser.screen_mut().check_visual_bell());
-    assert!(parser.screen_mut().check_audible_bell());
+    assert_eq!(parser.screen().audible_bell_count(), 1);
+    assert_eq!(parser.screen().visual_bell_count(), 1);
     assert!(parser.screen().application_keypad());
     assert!(parser.screen().application_cursor());
     assert!(parser.screen().hide_cursor());
@@ -87,7 +87,7 @@ fn ris() {
         vt100::MouseProtocolEncoding::Sgr
     );
 
-    parser.process(b"\x07\x1bg\x1bc");
+    parser.process(b"\x1bc");
     assert_eq!(parser.screen().cursor_position(), (0, 0));
 
     let cell = parser.screen().cell(0, 0).unwrap();
@@ -104,8 +104,8 @@ fn ris() {
     assert_eq!(parser.screen().icon_name(), "window icon name");
 
     // bell states don't change with reset
-    assert!(parser.screen_mut().check_visual_bell());
-    assert!(parser.screen_mut().check_audible_bell());
+    assert_eq!(parser.screen().audible_bell_count(), 1);
+    assert_eq!(parser.screen().visual_bell_count(), 1);
 
     assert!(!parser.screen().application_keypad());
     assert!(!parser.screen().application_cursor());
@@ -124,10 +124,14 @@ fn ris() {
 #[test]
 fn vb() {
     let mut parser = vt100::Parser::default();
-    assert!(!parser.screen_mut().check_visual_bell());
+    assert_eq!(parser.screen().visual_bell_count(), 0);
     parser.process(b"\x1bg");
-    assert!(parser.screen_mut().check_visual_bell());
-    assert!(!parser.screen_mut().check_visual_bell());
+    assert_eq!(parser.screen().visual_bell_count(), 1);
+    assert_eq!(parser.screen().visual_bell_count(), 1);
+    parser.process(b"\x1bg");
+    assert_eq!(parser.screen().visual_bell_count(), 2);
+    parser.process(b"\x1bg\x1bg\x1bg");
+    assert_eq!(parser.screen().visual_bell_count(), 5);
 }
 
 #[test]
diff --git a/tests/init.rs b/tests/init.rs
index ccb1c70..4e0cd66 100644
--- a/tests/init.rs
+++ b/tests/init.rs
@@ -2,7 +2,7 @@
 
 #[test]
 fn init() {
-    let mut parser = vt100::Parser::default();
+    let parser = vt100::Parser::default();
     assert_eq!(parser.screen().size(), (24, 80));
     assert_eq!(parser.screen().cursor_position(), (0, 0));
 
@@ -24,8 +24,8 @@ fn init() {
     assert_eq!(parser.screen().title(), "");
     assert_eq!(parser.screen().icon_name(), "");
 
-    assert!(!parser.screen_mut().check_visual_bell());
-    assert!(!parser.screen_mut().check_audible_bell());
+    assert_eq!(parser.screen().audible_bell_count(), 0);
+    assert_eq!(parser.screen().visual_bell_count(), 0);
     assert!(!parser.screen().application_keypad());
     assert!(!parser.screen().application_cursor());
     assert!(!parser.screen().hide_cursor());
diff --git a/tests/scroll.rs b/tests/scroll.rs
index 32b7488..2b1117e 100644
--- a/tests/scroll.rs
+++ b/tests/scroll.rs
@@ -82,31 +82,31 @@ fn scrollback() {
     parser.process(b"\r\n25\r\n26\r\n27\r\n28\r\n29\r\n30");
     assert_eq!(parser.screen().contents(), "7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24\n25\n26\n27\n28\n29\n30");
 
-    parser.screen_mut().set_scrollback(0);
+    parser.set_scrollback(0);
     assert_eq!(parser.screen().scrollback(), 0);
     assert_eq!(parser.screen().contents(), "7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24\n25\n26\n27\n28\n29\n30");
 
-    parser.screen_mut().set_scrollback(1);
+    parser.set_scrollback(1);
     assert_eq!(parser.screen().scrollback(), 1);
     assert_eq!(parser.screen().contents(), "6\n7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24\n25\n26\n27\n28\n29");
 
-    parser.screen_mut().set_scrollback(3);
+    parser.set_scrollback(3);
     assert_eq!(parser.screen().scrollback(), 3);
     assert_eq!(parser.screen().contents(), "4\n5\n6\n7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24\n25\n26\n27");
 
-    parser.screen_mut().set_scrollback(6);
+    parser.set_scrollback(6);
     assert_eq!(parser.screen().scrollback(), 6);
     assert_eq!(parser.screen().contents(), "1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24");
 
-    parser.screen_mut().set_scrollback(7);
+    parser.set_scrollback(7);
     assert_eq!(parser.screen().scrollback(), 6);
     assert_eq!(parser.screen().contents(), "1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24");
 
-    parser.screen_mut().set_scrollback(0);
+    parser.set_scrollback(0);
     assert_eq!(parser.screen().scrollback(), 0);
     assert_eq!(parser.screen().contents(), "7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24\n25\n26\n27\n28\n29\n30");
 
-    parser.screen_mut().set_scrollback(7);
+    parser.set_scrollback(7);
     assert_eq!(parser.screen().scrollback(), 6);
     assert_eq!(parser.screen().contents(), "1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24");
 
@@ -134,11 +134,11 @@ fn scrollback() {
     assert_eq!(parser.screen().scrollback(), 10);
     assert_eq!(parser.screen().contents(), "3\n4\n5\n6\n7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24\n25\n26");
 
-    parser.screen_mut().set_scrollback(12);
+    parser.set_scrollback(12);
     assert_eq!(parser.screen().scrollback(), 10);
     assert_eq!(parser.screen().contents(), "3\n4\n5\n6\n7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24\n25\n26");
 
-    parser.screen_mut().set_scrollback(0);
+    parser.set_scrollback(0);
     assert_eq!(parser.screen().scrollback(), 0);
     assert_eq!(parser.screen().contents(), "13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24\n25\n26\n27\n28\n29\n30\n31\n32\n33\n34\n35\n36");
 
@@ -146,7 +146,7 @@ fn scrollback() {
     assert_eq!(parser.screen().scrollback(), 0);
     assert_eq!(parser.screen().contents(), "15\n16\n17\n18\n19\n20\n21\n22\n23\n24\n25\n26\n27\n28\n29\n30\n31\n32\n33\n34\n35\n36\n37\n38");
 
-    parser.screen_mut().set_scrollback(5);
+    parser.set_scrollback(5);
     assert_eq!(parser.screen().scrollback(), 5);
     assert_eq!(parser.screen().contents(), "10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24\n25\n26\n27\n28\n29\n30\n31\n32\n33");