Add writable /self alias alongside /public and /data

cli/src/broker.rs

@@ -257,6 +257,7 @@ impl Broker {
             mounts: vec![
                 Mount { guest: "/".into(), host: self.world.root.clone(), writable: true },
                 Mount { guest: "/actor".into(), host: self.world.actors_root(), writable: true },
+                Mount { guest: "/self".into(), host: own.clone(), writable: true },
                 Mount { guest: "/public".into(), host: own.join("public"), writable: true },
                 Mount { guest: "/data".into(), host: own.join("data"), writable: true },
             ],

cli/src/world.rs

@@ -1,6 +1,7 @@
 //! On-disk layout of a Sausage world. The folder is the source of truth:
 //! `sausage run` boots every actor that it finds in `actor/`, and then
-//! watches the folder (`watch.rs`).
+//! watches the folder (`watch.rs`). `/self` aliases the running actor's folder;
+//! `/public` and `/data` remain aliases for its `public/` and `data/`.
 //!
 //! ```text
 //! <world>/              mounted at /, readable and writable by every actor
@@ -194,7 +195,8 @@ impl World {
     /// Map a path in an actor's namespace to a host path.
     ///
     /// - Absolute paths are relative to the world root.
-    /// - `/public/...` and `/data/...` alias `sender`'s folders.
+    /// - `/self/...` aliases `sender`'s folder; `/public/...` and `/data/...`
+    ///   alias its corresponding children.
     /// - Native senders (the console) can also give absolute host paths.
     pub fn resolve(&self, sender: &str, path: &str) -> Result<PathBuf> {
         let under = |base: PathBuf, rest: &str| -> Result<PathBuf> {
@@ -214,6 +216,9 @@ impl World {
         if let Some(rest) = prefixed("/actor") {
             return under(self.actors_root(), rest);
         }
+        if let Some(rest) = prefixed("/self") {
+            return under(self.actor_dir(sender), rest);
+        }
         if let Some(rest) = prefixed("/public") {
             return under(self.public_dir(sender), rest);
         }

cli/tests/host.rs

@@ -220,6 +220,8 @@ async fn actors_can_read_and_write_other_actor_data() {
 async fn world_root_is_shared_writable_and_survives_restart() {
     let (world, host, mut mailbox) = filesystem_world("world-root").await;
     assert!(world.root.join("config").is_dir());
+    ask_type(&host, &mut mailbox, "writer", json!({"type": "write", "path": "/self/data/x", "text": "self-alias"}), "ok").await;
+    assert_eq!(ask_type(&host, &mut mailbox, "writer", json!({"type": "read", "path": "/data/x"}), "content").await.body["text"], "self-alias");
     let file = "/config/x";
     ask_type(&host, &mut mailbox, "writer", json!({"type": "write", "path": file, "text": "first"}), "ok").await;
     let read = json!({"type": "read", "path": file});