a second instance on one machine: its own data, its own peer port, and a join that says itself again when it was never seated

src-tauri/src/paths.rs

@@ -0,0 +1,36 @@
+//! Where this instance keeps everything it writes.
+//!
+//! One directory holds the library, the caches and the whole Freenet side —
+//! persona, ledgers, node config and data. In a **debug build** the
+//! `SOULSTREAM_DATA_DIR` environment variable moves it, and that is what makes
+//! a second instance possible on one machine.
+//!
+//! That matters more than a convenience: most of the Community track is
+//! two-sided and cannot be exercised with one account at all. Accepting a
+//! friend request, a Space invitation and the join that answers it, removing a
+//! member, rotating an epoch key, a proposal ping actually arriving — every one
+//! of those had only unit tests until there was a second instance to talk to.
+//!
+//! A release build ignores the variable. An app whose data directory can be
+//! redirected from the environment is an app whose identity can be redirected
+//! from the environment, and the persona lives down there.
+//!
+//! A second instance also needs its own **node port** (`freenet_ws_port` in its
+//! config, which the app now passes through to the peer it spawns) and, for
+//! CDP, its own `SOULSTREAM_CDP_PORT`. Nothing else is shared: two instances
+//! must never point at one library.db.
+
+use std::path::PathBuf;
+
+use tauri::Manager;
+
+/// The root this instance writes under.
+pub fn app_data(app: &tauri::AppHandle) -> Result<PathBuf, String> {
+    #[cfg(debug_assertions)]
+    if let Some(dir) = std::env::var_os("SOULSTREAM_DATA_DIR") {
+        let dir = PathBuf::from(dir);
+        std::fs::create_dir_all(&dir).map_err(|e| format!("SOULSTREAM_DATA_DIR: {e}"))?;
+        return Ok(dir);
+    }
+    app.path().app_data_dir().map_err(|e| e.to_string())
+}