lua: add GuiWin and PaneObject proxies for use in script

This commit adds very basic first passes at representing the Pane
and GuiWindow types in lua script.

The `open-uri` event from 9397f2a2db
has been redefined to receive `(window, pane, uri)` parameters
instead of its prior very basic `uri` parameter.

A new key assignment `wezterm.action{EmitEvent="event-name"}` is
now available that allows a key binding assignment to emit an arbitrary
event, which in turn allows for triggering an arbitrary lua callback
in response to a key or mouse click.

`EmitEvent` passes the `(window, pane)` from the triggering window and
pane as parameters.

Here's a brief example:

```lua
local wezterm = require 'wezterm';

wezterm.on("my-thingy", function(window, pane)
  local dims = pane:get_dimensions();
  wezterm.log_error("did my thingy with window " .. window:window_id() ..
    " pane " .. pane:pane_id() .. " " .. dims.cols .. "x" .. dims.viewport_rows);
  window:perform_action("IncreaseFontSize", pane);
end)

return {
  keys = {
     {key="E", mods="CTRL", action=wezterm.action{EmitEvent="my-thingy"}},
  }
}
```

refs: #223
refs: #225

Cargo.lock

@@ -2048,6 +2048,7 @@ dependencies = [
  "downcast-rs",
  "libc",
  "log",
+ "luahelper",
  "portable-pty",
  "promise",
  "rangeset",

config/src/keyassignment.rs

@@ -155,6 +155,7 @@ pub enum KeyAssignment {
     ActivatePaneDirection(PaneDirection),
     TogglePaneZoomState,
     CloseCurrentPane { confirm: bool },
+    EmitEvent(String),
 }
 impl_lua_conversion!(KeyAssignment);
 

config/src/lib.rs

@@ -142,7 +142,7 @@ pub fn designate_this_as_the_main_thread() {
 /// call from a secondary thread.
 pub async fn with_lua_config_on_main_thread<F, RETF, RET>(func: F) -> anyhow::Result<RET>
 where
-    F: Fn(Option<Rc<mlua::Lua>>) -> RETF,
+    F: FnOnce(Option<Rc<mlua::Lua>>) -> RETF,
     RETF: Future<Output = anyhow::Result<RET>>,
 {
     let lua = LUA_CONFIG.with(|lc| {

luahelper/src/lib.rs

@@ -1,6 +1,7 @@
 #![macro_use]
 
 mod serde_lua;
+pub use mlua;
 pub use serde_lua::from_lua_value;
 pub use serde_lua::ser::to_lua_value;
 
@@ -13,27 +14,22 @@ pub use serde_lua::ser::to_lua_value;
 #[macro_export]
 macro_rules! impl_lua_conversion {
     ($struct:ident) => {
-        impl<'lua> mlua::ToLua<'lua> for $struct {
-            fn to_lua(self, lua: &'lua mlua::Lua) -> Result<mlua::Value<'lua>, mlua::Error> {
+        impl<'lua> $crate::mlua::ToLua<'lua> for $struct {
+            fn to_lua(
+                self,
+                lua: &'lua $crate::mlua::Lua,
+            ) -> Result<$crate::mlua::Value<'lua>, $crate::mlua::Error> {
                 Ok(luahelper::to_lua_value(lua, self)?)
             }
         }
 
-        impl<'lua> mlua::FromLua<'lua> for $struct {
+        impl<'lua> $crate::mlua::FromLua<'lua> for $struct {
             fn from_lua(
-                value: mlua::Value<'lua>,
-                _lua: &'lua mlua::Lua,
-            ) -> Result<Self, mlua::Error> {
+                value: $crate::mlua::Value<'lua>,
+                _lua: &'lua $crate::mlua::Lua,
+            ) -> Result<Self, $crate::mlua::Error> {
                 Ok(luahelper::from_lua_value(value)?)
             }
         }
     };
 }
-
-#[cfg(test)]
-mod tests {
-    #[test]
-    fn it_works() {
-        assert_eq!(2 + 2, 4);
-    }
-}

mux/Cargo.toml

@@ -14,6 +14,7 @@ config = { path = "../config" }
 downcast-rs = "1.0"
 libc = "0.2"
 log = "0.4"
+luahelper = { path = "../luahelper" }
 portable-pty = { path = "../pty", features = ["serde_support"]}
 promise = { path = "../promise" }
 rangeset = { path = "../rangeset" }

mux/src/renderable.rs

@@ -1,5 +1,6 @@
 use config::configuration;
 use downcast_rs::{impl_downcast, Downcast};
+use luahelper::impl_lua_conversion;
 use rangeset::RangeSet;
 use serde::{Deserialize, Serialize};
 use std::ops::Range;
@@ -13,6 +14,7 @@ pub struct StableCursorPosition {
     pub shape: termwiz::surface::CursorShape,
     pub visibility: termwiz::surface::CursorVisibility,
 }
+impl_lua_conversion!(StableCursorPosition);
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Default, Deserialize, Serialize)]
 pub struct RenderableDimensions {
@@ -33,6 +35,7 @@ pub struct RenderableDimensions {
     /// expressed as a stable index.
     pub scrollback_top: StableRowIndex,
 }
+impl_lua_conversion!(RenderableDimensions);
 
 /// Renderable allows passing something that isn't an actual wezterm_term::Terminal
 /// instance into the renderer, which opens up remoting of the terminal

wezterm/src/gui/mod.rs

@@ -17,6 +17,7 @@ mod termwindow;
 mod utilsprites;
 
 pub use selection::SelectionMode;
+pub use termwindow::TermWindow;
 
 pub struct GuiFrontEnd {
     connection: Rc<Connection>,

wezterm/src/gui/termwindow.rs

@@ -12,6 +12,8 @@ use crate::gui::overlay::{
 use crate::gui::scrollbar::*;
 use crate::gui::selection::*;
 use crate::gui::tabbar::{TabBarItem, TabBarState};
+use crate::scripting::guiwin::GuiWin;
+use crate::scripting::pane::PaneObject;
 use ::wezterm_term::input::MouseButton as TMB;
 use ::wezterm_term::input::MouseEventKind as TMEK;
 use ::window::bitmaps::atlas::{OutOfTextureSpace, SpriteSlice};
@@ -251,7 +253,7 @@ pub struct TermWindow {
     dimensions: Dimensions,
     /// Terminal dimensions
     terminal_size: PtySize,
-    mux_window_id: MuxWindowId,
+    pub mux_window_id: MuxWindowId,
     render_metrics: RenderMetrics,
     render_state: RenderState,
     input_map: InputMap,
@@ -1790,7 +1792,7 @@ impl TermWindow {
         .detach();
     }
 
-    fn perform_key_assignment(
+    pub fn perform_key_assignment(
         &mut self,
         pane: &Rc<dyn Pane>,
         assignment: &KeyAssignment,
@@ -1882,13 +1884,18 @@ impl TermWindow {
                 // perform below; here we allow the user to define an `open-uri` event
                 // handler that can bypass the normal `open::that` functionality.
                 if let Some(link) = self.current_highlight.as_ref().cloned() {
+                    let window = GuiWin::new(self);
+                    let pane = PaneObject::new(pane);
+
                     async fn open_uri(
                         lua: Option<Rc<mlua::Lua>>,
+                        window: GuiWin,
+                        pane: PaneObject,
                         link: String,
                     ) -> anyhow::Result<()> {
                         let default_click = match lua {
                             Some(lua) => {
-                                let args = lua.pack_multi(link.clone())?;
+                                let args = lua.pack_multi((window, pane, link.clone()))?;
                                 config::lua::emit_event(&lua, ("open-uri".to_string(), args))
                                     .await
                                     .map_err(|e| {
@@ -1908,11 +1915,39 @@ impl TermWindow {
                     }
 
                     promise::spawn::spawn(config::with_lua_config_on_main_thread(move |lua| {
-                        open_uri(lua, link.uri().to_string())
+                        open_uri(lua, window, pane, link.uri().to_string())
                     }))
                     .detach();
                 }
             }
+            EmitEvent(name) => {
+                let window = GuiWin::new(self);
+                let pane = PaneObject::new(pane);
+
+                async fn emit_event(
+                    lua: Option<Rc<mlua::Lua>>,
+                    name: String,
+                    window: GuiWin,
+                    pane: PaneObject,
+                ) -> anyhow::Result<()> {
+                    if let Some(lua) = lua {
+                        let args = lua.pack_multi((window, pane))?;
+                        config::lua::emit_event(&lua, (name.clone(), args))
+                            .await
+                            .map_err(|e| {
+                                log::error!("while processing EmitEvent({}): {:#}", name, e);
+                                e
+                            })?;
+                    }
+                    Ok(())
+                }
+
+                let name = name.to_string();
+                promise::spawn::spawn(config::with_lua_config_on_main_thread(move |lua| {
+                    emit_event(lua, name, window, pane)
+                }))
+                .detach();
+            }
             CompleteSelectionOrOpenLinkAtMouseCursor => {
                 let text = self.selection_text(pane);
                 if !text.is_empty() {

wezterm/src/main.rs

@@ -21,6 +21,7 @@ mod connui;
 mod gui;
 use config::keyassignment;
 mod markdown;
+mod scripting;
 mod server;
 mod ssh;
 mod stats;

wezterm/src/scripting/guiwin.rs

@@ -0,0 +1,59 @@
+//! GuiWin represents a Gui TermWindow (as opposed to a Mux window) in lua code
+use super::luaerr;
+use super::pane::PaneObject;
+use crate::gui::TermWindow;
+use anyhow::anyhow;
+use config::keyassignment::KeyAssignment;
+use mlua::{UserData, UserDataMethods};
+use mux::window::WindowId as MuxWindowId;
+use window::WindowOps;
+
+#[derive(Clone)]
+pub struct GuiWin {
+    mux_window_id: MuxWindowId,
+    window: ::window::Window,
+}
+
+impl GuiWin {
+    pub fn new(term_window: &TermWindow) -> Self {
+        let window = term_window.window.clone().unwrap();
+        let mux_window_id = term_window.mux_window_id;
+        Self {
+            window,
+            mux_window_id,
+        }
+    }
+
+    async fn with_term_window<F, T>(&self, mut f: F) -> mlua::Result<T>
+    where
+        F: FnMut(&mut TermWindow, &dyn WindowOps) -> anyhow::Result<T>,
+        F: Send + 'static,
+        T: Send + 'static,
+    {
+        self.window
+            .apply(move |tw, ops| {
+                if let Some(term_window) = tw.downcast_mut::<TermWindow>() {
+                    f(term_window, ops)
+                } else {
+                    Err(anyhow!("Window is not TermWindow!?"))
+                }
+            })
+            .await
+            .map_err(luaerr)
+    }
+}
+
+impl UserData for GuiWin {
+    fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
+        methods.add_method("window_id", |_, this, _: ()| Ok(this.mux_window_id));
+        methods.add_async_method(
+            "perform_action",
+            |_, this, (assignment, pane): (KeyAssignment, PaneObject)| async move {
+                this.with_term_window(move |term_window, _ops| {
+                    term_window.perform_key_assignment(&pane.pane()?, &assignment)
+                })
+                .await
+            },
+        );
+    }
+}

wezterm/src/scripting/mod.rs

@@ -0,0 +1,6 @@
+pub mod guiwin;
+pub mod pane;
+
+fn luaerr(err: anyhow::Error) -> mlua::Error {
+    mlua::Error::external(err)
+}

wezterm/src/scripting/pane.rs

@@ -0,0 +1,52 @@
+//! PaneObject represents a Mux Pane instance in lua code
+use super::luaerr;
+use anyhow::anyhow;
+use mlua::{UserData, UserDataMethods};
+use mux::pane::{Pane, PaneId};
+use mux::Mux;
+use std::rc::Rc;
+
+#[derive(Clone)]
+pub struct PaneObject {
+    pane: PaneId,
+}
+
+impl PaneObject {
+    pub fn new(pane: &Rc<dyn Pane>) -> Self {
+        Self {
+            pane: pane.pane_id(),
+        }
+    }
+
+    pub fn pane(&self) -> mlua::Result<Rc<dyn Pane>> {
+        let mux = Mux::get()
+            .ok_or_else(|| anyhow!("must be called on main thread"))
+            .map_err(luaerr)?;
+        mux.get_pane(self.pane)
+            .ok_or_else(|| anyhow!("pane id {} is not valid", self.pane))
+            .map_err(luaerr)
+    }
+}
+
+impl UserData for PaneObject {
+    fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
+        methods.add_method("pane_id", |_, this, _: ()| Ok(this.pane()?.pane_id()));
+        methods.add_method("get_title", |_, this, _: ()| Ok(this.pane()?.get_title()));
+        methods.add_method("get_current_working_dir", |_, this, _: ()| {
+            Ok(this
+                .pane()?
+                .get_current_working_dir()
+                .map(|u| u.to_string()))
+        });
+        methods.add_method("paste", |_, this, text: String| {
+            this.pane()?.send_paste(&text).map_err(luaerr)?;
+            Ok(())
+        });
+        methods.add_method("get_cursor_position", |_, this, _: ()| {
+            Ok(this.pane()?.renderer().get_cursor_position())
+        });
+        methods.add_method("get_dimensions", |_, this, _: ()| {
+            Ok(this.pane()?.renderer().get_dimensions())
+        });
+    }
+}