Merge remote-tracking branch 'origin/master' into line_ending_detection

1 files changed, 226 insertions, 0 deletions

diff --git a/helix-view/src/input.rs b/helix-view/src/input.rs
new file mode 100644
index 00000000..ab417819
--- /dev/null
+++ b/helix-view/src/input.rs
@@ -0,0 +1,226 @@
+//! Input event handling, currently backed by crossterm.
+use anyhow::{anyhow, Error};
+use crossterm::event;
+use serde::de::{self, Deserialize, Deserializer};
+use std::fmt;
+
+pub use crossterm::event::{KeyCode, KeyModifiers};
+
+/// Represents a key event.
+// We use a newtype here because we want to customize Deserialize and Display.
+#[derive(Debug, PartialEq, Eq, PartialOrd, Clone, Copy, Hash)]
+pub struct KeyEvent {
+    pub code: KeyCode,
+    pub modifiers: KeyModifiers,
+}
+
+impl fmt::Display for KeyEvent {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_fmt(format_args!(
+            "{}{}{}",
+            if self.modifiers.contains(KeyModifiers::SHIFT) {
+                "S-"
+            } else {
+                ""
+            },
+            if self.modifiers.contains(KeyModifiers::ALT) {
+                "A-"
+            } else {
+                ""
+            },
+            if self.modifiers.contains(KeyModifiers::CONTROL) {
+                "C-"
+            } else {
+                ""
+            },
+        ))?;
+        match self.code {
+            KeyCode::Backspace => f.write_str("backspace")?,
+            KeyCode::Enter => f.write_str("ret")?,
+            KeyCode::Left => f.write_str("left")?,
+            KeyCode::Right => f.write_str("right")?,
+            KeyCode::Up => f.write_str("up")?,
+            KeyCode::Down => f.write_str("down")?,
+            KeyCode::Home => f.write_str("home")?,
+            KeyCode::End => f.write_str("end")?,
+            KeyCode::PageUp => f.write_str("pageup")?,
+            KeyCode::PageDown => f.write_str("pagedown")?,
+            KeyCode::Tab => f.write_str("tab")?,
+            KeyCode::BackTab => f.write_str("backtab")?,
+            KeyCode::Delete => f.write_str("del")?,
+            KeyCode::Insert => f.write_str("ins")?,
+            KeyCode::Null => f.write_str("null")?,
+            KeyCode::Esc => f.write_str("esc")?,
+            KeyCode::Char('<') => f.write_str("lt")?,
+            KeyCode::Char('>') => f.write_str("gt")?,
+            KeyCode::Char('+') => f.write_str("plus")?,
+            KeyCode::Char('-') => f.write_str("minus")?,
+            KeyCode::Char(';') => f.write_str("semicolon")?,
+            KeyCode::Char('%') => f.write_str("percent")?,
+            KeyCode::F(i) => f.write_fmt(format_args!("F{}", i))?,
+            KeyCode::Char(c) => f.write_fmt(format_args!("{}", c))?,
+        };
+        Ok(())
+    }
+}
+
+impl std::str::FromStr for KeyEvent {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let mut tokens: Vec<_> = s.split('-').collect();
+        let code = match tokens.pop().ok_or_else(|| anyhow!("Missing key code"))? {
+            "backspace" => KeyCode::Backspace,
+            "space" => KeyCode::Char(' '),
+            "ret" => KeyCode::Enter,
+            "lt" => KeyCode::Char('<'),
+            "gt" => KeyCode::Char('>'),
+            "plus" => KeyCode::Char('+'),
+            "minus" => KeyCode::Char('-'),
+            "semicolon" => KeyCode::Char(';'),
+            "percent" => KeyCode::Char('%'),
+            "left" => KeyCode::Left,
+            "right" => KeyCode::Right,
+            "up" => KeyCode::Down,
+            "home" => KeyCode::Home,
+            "end" => KeyCode::End,
+            "pageup" => KeyCode::PageUp,
+            "pagedown" => KeyCode::PageDown,
+            "tab" => KeyCode::Tab,
+            "backtab" => KeyCode::BackTab,
+            "del" => KeyCode::Delete,
+            "ins" => KeyCode::Insert,
+            "null" => KeyCode::Null,
+            "esc" => KeyCode::Esc,
+            single if single.len() == 1 => KeyCode::Char(single.chars().next().unwrap()),
+            function if function.len() > 1 && function.starts_with('F') => {
+                let function: String = function.chars().skip(1).collect();
+                let function = str::parse::<u8>(&function)?;
+                (function > 0 && function < 13)
+                    .then(|| KeyCode::F(function))
+                    .ok_or_else(|| anyhow!("Invalid function key '{}'", function))?
+            }
+            invalid => return Err(anyhow!("Invalid key code '{}'", invalid)),
+        };
+
+        let mut modifiers = KeyModifiers::empty();
+        for token in tokens {
+            let flag = match token {
+                "S" => KeyModifiers::SHIFT,
+                "A" => KeyModifiers::ALT,
+                "C" => KeyModifiers::CONTROL,
+                _ => return Err(anyhow!("Invalid key modifier '{}-'", token)),
+            };
+
+            if modifiers.contains(flag) {
+                return Err(anyhow!("Repeated key modifier '{}-'", token));
+            }
+            modifiers.insert(flag);
+        }
+
+        Ok(KeyEvent { code, modifiers })
+    }
+}
+
+impl<'de> Deserialize<'de> for KeyEvent {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        s.parse().map_err(de::Error::custom)
+    }
+}
+
+impl From<event::KeyEvent> for KeyEvent {
+    fn from(event::KeyEvent { code, modifiers }: event::KeyEvent) -> KeyEvent {
+        KeyEvent { code, modifiers }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn parsing_unmodified_keys() {
+        assert_eq!(
+            str::parse::<KeyEvent>("backspace").unwrap(),
+            KeyEvent {
+                code: KeyCode::Backspace,
+                modifiers: KeyModifiers::NONE
+            }
+        );
+
+        assert_eq!(
+            str::parse::<KeyEvent>("left").unwrap(),
+            KeyEvent {
+                code: KeyCode::Left,
+                modifiers: KeyModifiers::NONE
+            }
+        );
+
+        assert_eq!(
+            str::parse::<KeyEvent>(",").unwrap(),
+            KeyEvent {
+                code: KeyCode::Char(','),
+                modifiers: KeyModifiers::NONE
+            }
+        );
+
+        assert_eq!(
+            str::parse::<KeyEvent>("w").unwrap(),
+            KeyEvent {
+                code: KeyCode::Char('w'),
+                modifiers: KeyModifiers::NONE
+            }
+        );
+
+        assert_eq!(
+            str::parse::<KeyEvent>("F12").unwrap(),
+            KeyEvent {
+                code: KeyCode::F(12),
+                modifiers: KeyModifiers::NONE
+            }
+        );
+    }
+
+    #[test]
+    fn parsing_modified_keys() {
+        assert_eq!(
+            str::parse::<KeyEvent>("S-minus").unwrap(),
+            KeyEvent {
+                code: KeyCode::Char('-'),
+                modifiers: KeyModifiers::SHIFT
+            }
+        );
+
+        assert_eq!(
+            str::parse::<KeyEvent>("C-A-S-F12").unwrap(),
+            KeyEvent {
+                code: KeyCode::F(12),
+                modifiers: KeyModifiers::SHIFT | KeyModifiers::CONTROL | KeyModifiers::ALT
+            }
+        );
+
+        assert_eq!(
+            str::parse::<KeyEvent>("S-C-2").unwrap(),
+            KeyEvent {
+                code: KeyCode::Char('2'),
+                modifiers: KeyModifiers::SHIFT | KeyModifiers::CONTROL
+            }
+        );
+    }
+
+    #[test]
+    fn parsing_nonsensical_keys_fails() {
+        assert!(str::parse::<KeyEvent>("F13").is_err());
+        assert!(str::parse::<KeyEvent>("F0").is_err());
+        assert!(str::parse::<KeyEvent>("aaa").is_err());
+        assert!(str::parse::<KeyEvent>("S-S-a").is_err());
+        assert!(str::parse::<KeyEvent>("C-A-S-C-1").is_err());
+        assert!(str::parse::<KeyEvent>("FU").is_err());
+        assert!(str::parse::<KeyEvent>("123").is_err());
+        assert!(str::parse::<KeyEvent>("S--").is_err());
+    }
+}