cli: add command to restart the compositor in place

src/cli/reexec.rs

@@ -0,0 +1,80 @@
+use {
+    crate::{
+        cli::GlobalArgs,
+        tools::tool_client::{Handle, ToolClient, with_tool_client},
+        utils::errorfmt::ErrorFmt,
+        wire::{jay_compositor, jay_reexec},
+    },
+    clap::Args,
+    std::rc::Rc,
+};
+
+#[derive(Args, Debug)]
+pub struct ReexecArgs {
+    /// The path to the new executable.
+    ///
+    /// If this is not given, uses the path of **this** executable instead.
+    path: Option<String>,
+    /// The arguments to pass to the new executable.
+    args: Vec<String>,
+}
+
+pub fn main(global: GlobalArgs, reexec_args: ReexecArgs) {
+    with_tool_client(global.log_level.into(), |tc| async move {
+        let rexec = Rc::new(Reexec { tc: tc.clone() });
+        rexec.run(reexec_args).await;
+    });
+}
+
+struct Reexec {
+    tc: Rc<ToolClient>,
+}
+
+impl Reexec {
+    async fn run(&self, args: ReexecArgs) {
+        let tc = &self.tc;
+        let comp = tc.jay_compositor().await;
+        let reexec = tc.id();
+        tc.send(jay_compositor::Reexec {
+            self_id: comp,
+            id: reexec,
+        });
+        if let Some(path) = &args.path {
+            for arg in &args.args {
+                tc.send(jay_reexec::Arg {
+                    self_id: reexec,
+                    arg,
+                });
+            }
+            tc.send(jay_reexec::Exec {
+                self_id: reexec,
+                path,
+            });
+        } else {
+            let exe = match std::env::current_exe() {
+                Ok(e) => e,
+                Err(e) => {
+                    log::error!("Could not determine the executable path: {}", ErrorFmt(e));
+                    std::process::exit(1);
+                }
+            };
+            let Some(exe) = exe.to_str() else {
+                log::error!("Executable path is not a string: {:?}", exe);
+                std::process::exit(1);
+            };
+            tc.send(jay_reexec::Arg {
+                self_id: reexec,
+                arg: "run",
+            });
+            tc.send(jay_reexec::Exec {
+                self_id: reexec,
+                path: exe,
+            });
+        }
+        jay_reexec::Failed::handle(tc, reexec, (), |_, msg| {
+            log::error!("Exec failed: {}", msg.msg);
+            std::process::exit(1);
+        });
+        tc.round_trip().await;
+    }
+}