add Pane::get_metadata

The idea here is that different kinds of panes may want to expose
additional metadata to lua scripts. It would be a bit weird to add
a Pane method for each of those and plumb it all the way through
the various APIs, so just allowing a pane impl to return a dynamic
value (likely an Object) allows a bunch of flexibility.

This commit exposes the clientpane is_tardy boolean and the time
since the last data was recevied (since_last_response_ms) from
the mux client pane implementation: these are used to show the
tardiness indicator in the client pane.

Exposing this data enables the user to add that info to their
status bar if they wish.

Cargo.lock

@@ -5420,6 +5420,7 @@ dependencies = [
  "uds_windows",
  "umask",
  "url",
+ "wezterm-dynamic",
  "wezterm-ssh",
  "wezterm-term",
  "winapi",

mux/src/pane.rs

@@ -14,6 +14,7 @@ use termwiz::hyperlink::Rule;
 use termwiz::input::KeyboardEncoding;
 use termwiz::surface::{Line, SequenceNo};
 use url::Url;
+use wezterm_dynamic::Value;
 use wezterm_term::color::ColorPalette;
 use wezterm_term::{
     Clipboard, DownloadHandler, KeyCode, KeyModifiers, MouseEvent, SemanticZone, StableRowIndex,
@@ -204,6 +205,11 @@ pub trait Pane: Downcast {
 
     fn get_current_seqno(&self) -> SequenceNo;
 
+    /// Returns misc metadata that is pane-specific
+    fn get_metadata(&self) -> Value {
+        Value::Null
+    }
+
     /// Given a range of lines, return the subset of those lines that
     /// have changed since the supplied sequence no.
     fn get_changed_since(

wezterm-client/Cargo.toml

@@ -37,6 +37,7 @@ textwrap = "0.15"
 thiserror = "1.0"
 umask = { path = "../umask" }
 url = "2"
+wezterm-dynamic = { path = "../wezterm-dynamic" }
 wezterm-ssh = { path = "../wezterm-ssh" }
 wezterm-term = { path = "../term", features=["use_serde"] }
 

wezterm-client/src/pane/clientpane.rs

@@ -16,13 +16,14 @@ use mux::{Mux, MuxNotification};
 use rangeset::RangeSet;
 use ratelim::RateLimiter;
 use std::cell::{RefCell, RefMut};
-use std::collections::HashMap;
+use std::collections::{BTreeMap, HashMap};
 use std::ops::Range;
 use std::rc::Rc;
 use std::sync::Arc;
 use termwiz::input::KeyEvent;
 use termwiz::surface::SequenceNo;
 use url::Url;
+use wezterm_dynamic::Value;
 use wezterm_term::color::ColorPalette;
 use wezterm_term::{
     Alert, Clipboard, KeyCode, KeyModifiers, Line, MouseEvent, StableRowIndex, TerminalSize,
@@ -195,6 +196,23 @@ impl Pane for ClientPane {
         self.local_pane_id
     }
 
+    fn get_metadata(&self) -> Value {
+        let renderable = self.renderable.borrow();
+        let inner = renderable.inner.borrow();
+
+        let mut map: BTreeMap<Value, Value> = BTreeMap::new();
+        map.insert(
+            Value::String("is_tardy".to_string()),
+            Value::Bool(inner.is_tardy()),
+        );
+        map.insert(
+            Value::String("since_last_response_ms".to_string()),
+            Value::U64(inner.last_recv_time.elapsed().as_millis() as u64),
+        );
+
+        Value::Object(map.into())
+    }
+
     fn get_cursor_position(&self) -> StableCursorPosition {
         self.renderable.borrow().get_cursor_position()
     }

wezterm-client/src/pane/renderable.rs

@@ -72,7 +72,7 @@ pub struct RenderableInner {
     fetch_limiter: RateLimiter,
 
     last_send_time: Instant,
-    last_recv_time: Instant,
+    pub last_recv_time: Instant,
     last_late_dirty: Instant,
     last_input_rtt: u64,
 

wezterm-gui/src/scripting/pane.rs

@@ -1,6 +1,7 @@
 //! PaneObject represents a Mux Pane instance in lua code
 use super::luaerr;
 use anyhow::anyhow;
+use luahelper::dynamic_to_lua_value;
 use mlua::{UserData, UserDataMethods};
 use mux::pane::{Pane, PaneId};
 use mux::Mux;
@@ -48,6 +49,10 @@ impl UserData for PaneObject {
                 .get_current_working_dir()
                 .map(|u| u.to_string()))
         });
+        methods.add_method("get_metadata", |lua, this, _: ()| {
+            let value = this.pane()?.get_metadata();
+            dynamic_to_lua_value(lua, value)
+        });
         methods.add_method("get_foreground_process_name", |_, this, _: ()| {
             Ok(this.pane()?.get_foreground_process_name())
         });