Add CloseCurrentTab key binding

Added CMD-W as a default binding for this action.

refs: https://github.com/wez/wezterm/pull/26

README.md

@@ -144,6 +144,7 @@ The default key bindings are:
 | `SUPER`     | `0`      | `ResetFontSize` |
 | `CTRL`      | `0`      | `ResetFontSize` |
 | `SUPER`     | `t`      | `SpawnTab` |
+| `SUPER`     | `w`      | `CloseCurrentTab` |
 | `SUPER`     | `1`      | `ActivateTab(0)` |
 | `SUPER`     | `2`      | `ActivateTab(1)` |
 | `SUPER`     | `3`      | `ActivateTab(2)` |
@@ -217,6 +218,7 @@ specified via the `arg` key; see examples below.
 | `Nop` | Does nothing.  This is useful to disable a default key assignment. |
 | `Hide` | Hides the current window |
 | `Show` | Shows the current window |
+| `CloseCurrentTab` | Equivalent to clicking the `x` on the window title bar to close it: Closes the current tab.  If that was the last tab, closes that window.  If that was the last window, wezterm terminates. |
 
 Example:
 

src/config.rs

@@ -110,6 +110,7 @@ impl std::convert::TryInto<KeyAssignment> for &Key {
             KeyAction::DecreaseFontSize => KeyAssignment::DecreaseFontSize,
             KeyAction::ResetFontSize => KeyAssignment::ResetFontSize,
             KeyAction::Nop => KeyAssignment::Nop,
+            KeyAction::CloseCurrentTab => KeyAssignment::CloseCurrentTab,
             KeyAction::ActivateTab => KeyAssignment::ActivateTab(
                 self.arg
                     .as_ref()
@@ -148,6 +149,7 @@ pub enum KeyAction {
     Nop,
     Hide,
     Show,
+    CloseCurrentTab,
 }
 
 fn de_keycode<'de, D>(deserializer: D) -> Result<KeyCode, D::Error>

src/frontend/glium/window.rs

@@ -747,17 +747,7 @@ impl GliumTerminalWindow {
                 event: WindowEvent::CloseRequested,
                 ..
             } => {
-                let mux = Mux::get().unwrap();
-                let tab = match mux.get_active_tab_for_window(self.get_mux_window_id()) {
-                    Some(tab) => tab,
-                    None => return Ok(()),
-                };
-                mux.remove_tab(tab.tab_id());
-                if let Some(mut win) = mux.get_window_mut(self.get_mux_window_id()) {
-                    win.remove_by_id(tab.tab_id());
-                }
-                // Explicit drop of mux to satisfy the borrow checker
-                drop(mux);
+                self.host.close_current_tab();
             }
             _ => {}
         }

src/frontend/guicommon/host.rs

@@ -31,6 +31,7 @@ pub enum KeyAssignment {
     Nop,
     Hide,
     Show,
+    CloseCurrentTab,
 }
 
 pub trait HostHelper {
@@ -129,6 +130,7 @@ fn key_bindings() -> KeyMap {
         [KeyModifiers::CTRL, KeyCode::Char('0'), ResetFontSize],
         // Tab navigation and management
         [KeyModifiers::SUPER, KeyCode::Char('t'), SpawnTab],
+        [KeyModifiers::SUPER, KeyCode::Char('w'), CloseCurrentTab],
         [KeyModifiers::SUPER, KeyCode::Char('1'), ActivateTab(0)],
         [KeyModifiers::SUPER, KeyCode::Char('2'), ActivateTab(1)],
         [KeyModifiers::SUPER, KeyCode::Char('3'), ActivateTab(2)],
@@ -241,6 +243,7 @@ impl<H: HostHelper> HostImpl<H> {
             SendString(s) => tab.writer().write_all(s.as_bytes())?,
             Hide => self.hide_window(),
             Show => self.show_window(),
+            CloseCurrentTab => self.close_current_tab(),
             Nop => {}
         }
         Ok(())
@@ -291,6 +294,21 @@ impl<H: HostHelper> HostImpl<H> {
         })
     }
 
+    pub fn close_current_tab(&mut self) {
+        self.with_window(move |win| {
+            let mux = Mux::get().unwrap();
+            let tab = match mux.get_active_tab_for_window(win.get_mux_window_id()) {
+                Some(tab) => tab,
+                None => return Ok(()),
+            };
+            mux.remove_tab(tab.tab_id());
+            if let Some(mut win) = mux.get_window_mut(win.get_mux_window_id()) {
+                win.remove_by_id(tab.tab_id());
+            }
+            win.activate_tab_relative(0)
+        });
+    }
+
     pub fn hide_window(&mut self) {
         self.with_window(move |win| {
             win.hide_window();

src/frontend/guicommon/window.rs

@@ -5,7 +5,7 @@ use crate::mux::window::WindowId;
 use crate::mux::Mux;
 use crate::opengl::render::Renderer;
 use crate::opengl::textureatlas::OutOfTextureSpace;
-use failure::{format_err, Error};
+use failure::{ensure, format_err, Error};
 use glium;
 use portable_pty::PtySize;
 use std::rc::Rc;
@@ -71,6 +71,8 @@ pub trait TerminalWindow {
             .ok_or_else(|| format_err!("no such window"))?;
 
         let max = window.len();
+        ensure!(max > 0, "no more tabs");
+
         let active = window.get_active_idx() as isize;
         let tab = active + delta;
         let tab = if tab < 0 { max as isize + tab } else { tab };