Add custom event type replacing crossterm's Event (#3169)

Ported over from 61365dfbf3 in the `gui` branch. This will allow
adding our own events, most notably an idle timer event (useful
for adding debounced input in [dynamic pickers][1] used by interactive
global search and workspace symbols).

[1]: https://github.com/helix-editor/helix/pull/3110

Co-authored-by: Blaž Hrastnik <blaz@mxxn.io>

2 files changed, 101 insertions, 2 deletions

diff --git a/helix-view/src/input.rs b/helix-view/src/input.rs
index 093006c4..9ae3ce70 100644
--- a/helix-view/src/input.rs
+++ b/helix-view/src/input.rs
@@ -4,8 +4,53 @@ use helix_core::unicode::{segmentation::UnicodeSegmentation, width::UnicodeWidth
 use serde::de::{self, Deserialize, Deserializer};
 use std::fmt;
 
-use crate::keyboard::{KeyCode, KeyModifiers};
+pub use crate::keyboard::{KeyCode, KeyModifiers};
 
+#[derive(Debug, PartialOrd, PartialEq, Eq, Clone, Copy, Hash)]
+pub enum Event {
+    Key(KeyEvent),
+    Mouse(MouseEvent),
+    Resize(u16, u16),
+}
+
+#[derive(Debug, PartialOrd, PartialEq, Eq, Clone, Copy, Hash)]
+pub struct MouseEvent {
+    /// The kind of mouse event that was caused.
+    pub kind: MouseEventKind,
+    /// The column that the event occurred on.
+    pub column: u16,
+    /// The row that the event occurred on.
+    pub row: u16,
+    /// The key modifiers active when the event occurred.
+    pub modifiers: KeyModifiers,
+}
+
+#[derive(Debug, PartialOrd, PartialEq, Eq, Clone, Copy, Hash)]
+pub enum MouseEventKind {
+    /// Pressed mouse button. Contains the button that was pressed.
+    Down(MouseButton),
+    /// Released mouse button. Contains the button that was released.
+    Up(MouseButton),
+    /// Moved the mouse cursor while pressing the contained mouse button.
+    Drag(MouseButton),
+    /// Moved the mouse cursor while not pressing a mouse button.
+    Moved,
+    /// Scrolled mouse wheel downwards (towards the user).
+    ScrollDown,
+    /// Scrolled mouse wheel upwards (away from the user).
+    ScrollUp,
+}
+
+/// Represents a mouse button.
+#[derive(Debug, PartialOrd, PartialEq, Eq, Clone, Copy, Hash)]
+pub enum MouseButton {
+    /// Left mouse button.
+    Left,
+    /// Right mouse button.
+    Right,
+    /// Middle mouse button.
+    Middle,
+}
 /// Represents a key event.
 // We use a newtype here because we want to customize Deserialize and Display.
 #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Hash)]
@@ -220,6 +265,61 @@ impl<'de> Deserialize<'de> for KeyEvent {
 }
 
 #[cfg(feature = "term")]
+impl From<crossterm::event::Event> for Event {
+    fn from(event: crossterm::event::Event) -> Self {
+        match event {
+            crossterm::event::Event::Key(key) => Self::Key(key.into()),
+            crossterm::event::Event::Mouse(mouse) => Self::Mouse(mouse.into()),
+            crossterm::event::Event::Resize(w, h) => Self::Resize(w, h),
+        }
+    }
+}
+
+#[cfg(feature = "term")]
+impl From<crossterm::event::MouseEvent> for MouseEvent {
+    fn from(
+        crossterm::event::MouseEvent {
+            kind,
+            column,
+            row,
+            modifiers,
+        }: crossterm::event::MouseEvent,
+    ) -> Self {
+        Self {
+            kind: kind.into(),
+            column,
+            row,
+            modifiers: modifiers.into(),
+        }
+    }
+}
+
+#[cfg(feature = "term")]
+impl From<crossterm::event::MouseEventKind> for MouseEventKind {
+    fn from(kind: crossterm::event::MouseEventKind) -> Self {
+        match kind {
+            crossterm::event::MouseEventKind::Down(button) => Self::Down(button.into()),
+            crossterm::event::MouseEventKind::Up(button) => Self::Down(button.into()),
+            crossterm::event::MouseEventKind::Drag(button) => Self::Drag(button.into()),
+            crossterm::event::MouseEventKind::Moved => Self::Moved,
+            crossterm::event::MouseEventKind::ScrollDown => Self::ScrollDown,
+            crossterm::event::MouseEventKind::ScrollUp => Self::ScrollUp,
+        }
+    }
+}
+
+#[cfg(feature = "term")]
+impl From<crossterm::event::MouseButton> for MouseButton {
+    fn from(button: crossterm::event::MouseButton) -> Self {
+        match button {
+            crossterm::event::MouseButton::Left => MouseButton::Left,
+            crossterm::event::MouseButton::Right => MouseButton::Right,
+            crossterm::event::MouseButton::Middle => MouseButton::Middle,
+        }
+    }
+}
+
+#[cfg(feature = "term")]
 impl From<crossterm::event::KeyEvent> for KeyEvent {
     fn from(crossterm::event::KeyEvent { code, modifiers }: crossterm::event::KeyEvent) -> Self {
         if code == crossterm::event::KeyCode::BackTab {
diff --git a/helix-view/src/keyboard.rs b/helix-view/src/keyboard.rs
index 4d51f981..d1b45b05 100644
--- a/helix-view/src/keyboard.rs
+++ b/helix-view/src/keyboard.rs
@@ -55,7 +55,6 @@ impl From<crossterm::event::KeyModifiers> for KeyModifiers {
 
 /// Represents a key.
 #[derive(Debug, PartialOrd, Ord, PartialEq, Eq, Clone, Copy, Hash)]
-#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum KeyCode {
     /// Backspace key.
     Backspace,