From 27ab1b65a0d9a6ce5e1fd7b17159498e5dd59f7e Mon Sep 17 00:00:00 2001
From: Wez Furlong <wez@wezfurlong.org>
Date: Tue, 27 Feb 2018 08:00:06 -0800
Subject: [PATCH] Add support for F-keys

Fixes https://github.com/wez/wezterm/issues/11
---
 src/gliumwindows.rs       | 15 ++++++++++++
 term/src/input.rs         |  3 +++
 term/src/terminalstate.rs | 48 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/src/gliumwindows.rs b/src/gliumwindows.rs
index a09765a28..f0e532ab2 100644
--- a/src/gliumwindows.rs
+++ b/src/gliumwindows.rs
@@ -407,6 +407,21 @@ impl TerminalWindow {
                     // These are all handled by ReceivedCharacter
                     return Ok(());
                 }
+                V::F1 => KeyCode::F(1),
+                V::F2 => KeyCode::F(2),
+                V::F3 => KeyCode::F(3),
+                V::F4 => KeyCode::F(4),
+                V::F5 => KeyCode::F(5),
+                V::F6 => KeyCode::F(6),
+                V::F7 => KeyCode::F(7),
+                V::F8 => KeyCode::F(8),
+                V::F9 => KeyCode::F(9),
+                V::F10 => KeyCode::F(10),
+                V::F11 => KeyCode::F(11),
+                V::F12 => KeyCode::F(12),
+                V::F13 => KeyCode::F(13),
+                V::F14 => KeyCode::F(14),
+                V::F15 => KeyCode::F(15),
                 V::Insert => KeyCode::Insert,
                 V::Home => KeyCode::Home,
                 V::End => KeyCode::End,
diff --git a/term/src/input.rs b/term/src/input.rs
index 47c239abc..347b18603 100644
--- a/term/src/input.rs
+++ b/term/src/input.rs
@@ -10,6 +10,7 @@ bitflags! {
         const META = 4;
         const SUPER = 8;
         const SHIFT = 16;
+        const NONE = 0;
     }
 }
 
@@ -32,6 +33,8 @@ pub enum KeyCode {
     Home,
     End,
     Insert,
+    /// A numbered F-key
+    F(u8),
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
diff --git a/term/src/terminalstate.rs b/term/src/terminalstate.rs
index 719e9db92..a837cf087 100644
--- a/term/src/terminalstate.rs
+++ b/term/src/terminalstate.rs
@@ -1,4 +1,5 @@
 use super::*;
+use std::fmt::Write;
 use unicode_segmentation::UnicodeSegmentation;
 
 struct TabStop {
@@ -533,6 +534,7 @@ impl TerminalState {
         const CTRL: KeyModifiers = KeyModifiers::CTRL;
         const SHIFT: KeyModifiers = KeyModifiers::SHIFT;
         const ALT: KeyModifiers = KeyModifiers::ALT;
+        const NO: KeyModifiers = KeyModifiers::NONE;
         const APPCURSOR: bool = true;
         use KeyCode::*;
 
@@ -571,7 +573,6 @@ impl TerminalState {
             (Insert, _, _, SHIFT, _) => {
                 let clip = host.get_clipboard()?;
                 if self.bracketed_paste {
-                    use std::fmt::Write;
                     write!(buf, "\x1b[200~{}\x1b[201~", clip)?;
                 } else {
                     buf = clip;
@@ -606,6 +607,51 @@ impl TerminalState {
             (End, ..) => "\x1b[F",
             (Insert, ..) => "\x1b[2~",
 
+            (F(n), ..) => {
+                let modifier = match (ctrl, alt, shift) {
+                    (NO, NO, NO) => "",
+                    (NO, NO, SHIFT) => ";2",
+                    (NO, ALT, NO) => ";3",
+                    (NO, ALT, SHIFT) => ";4",
+                    (CTRL, NO, NO) => ";5",
+                    (CTRL, NO, SHIFT) => ";6",
+                    (CTRL, ALT, NO) => ";7",
+                    (CTRL, ALT, SHIFT) => ";8",
+                    _ => unreachable!("invalid modifiers!?"),
+                };
+
+                if modifier.len() == 0 && n < 5 {
+                    // F1-F4 are encoded using SS3 if there are no modifiers
+                    match n {
+                        1 => "\x1bOP",
+                        2 => "\x1bOQ",
+                        3 => "\x1bOR",
+                        4 => "\x1bOS",
+                        _ => unreachable!("wat?"),
+                    }
+                } else {
+                    // Higher numbered F-keys plus modified F-keys are encoded
+                    // using CSI instead of SS3.
+                    let intro = match n {
+                        1 => "\x1b[11",
+                        2 => "\x1b[12",
+                        3 => "\x1b[13",
+                        4 => "\x1b[14",
+                        5 => "\x1b[15",
+                        6 => "\x1b[17",
+                        7 => "\x1b[18",
+                        8 => "\x1b[19",
+                        9 => "\x1b[20",
+                        10 => "\x1b[21",
+                        11 => "\x1b[23",
+                        12 => "\x1b[24",
+                        _ => bail!("unhandled fkey number {}", n),
+                    };
+                    write!(buf, "{}{}~", intro, modifier)?;
+                    buf.as_str()
+                }
+            }
+
             // Modifier keys pressed on their own and unmappable keys don't expand to anything
             (Control, ..) | (Alt, ..) | (Meta, ..) | (Super, ..) | (Hyper, ..) | (Shift, ..)
             | (Unknown, ..) => "",