commit 2626ab342494a993f277cb3ebf8bdec7536b8a31
parent 59551e922e0b10a1e23f3bd9682fd4835bb00466
Author: triesap <tyson@radroots.org>
Date: Sun, 2 Aug 2026 19:36:34 +0000
ffi: add closeable snapshot observers
- bridge revisioned Rust snapshots to foreign callbacks
- deliver callbacks outside core locks to permit safe re-entry
- make observer subscriptions idempotently closeable
- deregister all callbacks when the application core closes
Diffstat:
4 files changed, 217 insertions(+), 8 deletions(-)
diff --git a/core/crates/ffi/src/commands.rs b/core/crates/ffi/src/commands.rs
@@ -1,5 +1,7 @@
+use std::collections::BTreeSet;
use std::fmt::{self, Display, Formatter};
use std::path::{Path, PathBuf};
+use std::sync::atomic::AtomicBool;
use std::sync::{Arc, Mutex, OnceLock};
use std::time::{Duration, SystemTime, UNIX_EPOCH};
@@ -57,16 +59,18 @@ impl RemovalRequest {
}
}
-struct RuntimeCore {
- adapter: PersistentAppCore,
- secrets: OsKeyringSecretStore,
- clock: SystemClock,
- nostr: SdkNostrClient,
+pub(crate) struct RuntimeCore {
+ pub(crate) adapter: PersistentAppCore,
+ pub(crate) secrets: OsKeyringSecretStore,
+ pub(crate) clock: SystemClock,
+ pub(crate) nostr: SdkNostrClient,
+ pub(crate) observers: Mutex<BTreeSet<radroots_studio_application::ObserverHandle>>,
+ pub(crate) closed: AtomicBool,
}
#[derive(uniffi::Object)]
pub struct StudioAppCore {
- inner: Arc<RuntimeCore>,
+ pub(crate) inner: Arc<RuntimeCore>,
}
#[uniffi::export]
@@ -278,13 +282,15 @@ impl StudioAppCore {
secrets: OsKeyringSecretStore,
clock: SystemClock,
nostr: SdkNostrClient::new(Duration::from_secs(5)),
+ observers: Mutex::new(BTreeSet::new()),
+ closed: AtomicBool::new(false),
}),
}))
}
}
#[derive(Clone, Copy)]
-struct SystemClock;
+pub(crate) struct SystemClock;
impl Clock for SystemClock {
fn now(&self) -> UnixTimestamp {
@@ -370,6 +376,8 @@ mod tests {
nostr: radroots_studio_application::SdkNostrClient::new(
std::time::Duration::from_millis(10),
),
+ observers: std::sync::Mutex::new(std::collections::BTreeSet::new()),
+ closed: std::sync::atomic::AtomicBool::new(false),
}),
})
}
diff --git a/core/crates/ffi/src/lib.rs b/core/crates/ffi/src/lib.rs
@@ -2,11 +2,13 @@
mod commands;
mod dto;
+mod observer;
pub use commands::{GeneratedAccountDto, RemovalRequest, StudioAppCore, StudioError};
pub use dto::{
AccountDto, ActiveAccountDto, AppLifecycleDto, AppSnapshotDto, KeyAvailabilityDto, ProfileDto,
ProfileLoadStateDto, RelayConnectionStateDto, SafeErrorDto, SessionStateDto, SignerKindDto,
};
+pub use observer::{ObserverSubscription, StudioObserver};
uniffi::setup_scaffolding!();
diff --git a/core/crates/ffi/src/observer.rs b/core/crates/ffi/src/observer.rs
@@ -0,0 +1,199 @@
+use std::sync::atomic::Ordering;
+use std::sync::{Arc, Mutex, Weak};
+
+use radroots_studio_application::{AppObserver, AppSnapshot, ObserverHandle};
+
+use crate::commands::RuntimeCore;
+use crate::{AppSnapshotDto, StudioAppCore, StudioError};
+
+#[uniffi::export(callback_interface)]
+pub trait StudioObserver: Send + Sync {
+ fn on_snapshot_changed(&self, snapshot: AppSnapshotDto);
+}
+
+struct ObserverBridge {
+ observer: Arc<dyn StudioObserver>,
+}
+
+impl AppObserver for ObserverBridge {
+ fn on_snapshot_changed(&self, snapshot: AppSnapshot) {
+ self.observer.on_snapshot_changed((&snapshot).into());
+ }
+}
+
+#[derive(uniffi::Object)]
+pub struct ObserverSubscription {
+ core: Weak<RuntimeCore>,
+ handle: Mutex<Option<ObserverHandle>>,
+}
+
+#[uniffi::export]
+impl ObserverSubscription {
+ pub fn close(&self) {
+ let handle = self
+ .handle
+ .lock()
+ .unwrap_or_else(std::sync::PoisonError::into_inner)
+ .take();
+ let (Some(core), Some(handle)) = (self.core.upgrade(), handle) else {
+ return;
+ };
+ let _ = core.adapter.core().unsubscribe(handle);
+ core.observers
+ .lock()
+ .unwrap_or_else(std::sync::PoisonError::into_inner)
+ .remove(&handle);
+ }
+}
+
+impl Drop for ObserverSubscription {
+ fn drop(&mut self) {
+ self.close();
+ }
+}
+
+#[uniffi::export]
+impl StudioAppCore {
+ /// Subscribes to revisioned snapshots and immediately delivers the current value.
+ ///
+ /// # Errors
+ ///
+ /// Returns a safe observer or lifecycle error.
+ pub fn subscribe(
+ &self,
+ observer: Box<dyn StudioObserver>,
+ ) -> Result<Arc<ObserverSubscription>, StudioError> {
+ if self.inner.closed.load(Ordering::Acquire) {
+ return Err(closed_error());
+ }
+ let bridge = Arc::new(ObserverBridge {
+ observer: Arc::from(observer),
+ });
+ let handle = self
+ .inner
+ .adapter
+ .core()
+ .subscribe(bridge)
+ .map_err(StudioError::from)?;
+ self.inner
+ .observers
+ .lock()
+ .unwrap_or_else(std::sync::PoisonError::into_inner)
+ .insert(handle);
+ Ok(Arc::new(ObserverSubscription {
+ core: Arc::downgrade(&self.inner),
+ handle: Mutex::new(Some(handle)),
+ }))
+ }
+
+ pub fn close(&self) {
+ if self.inner.closed.swap(true, Ordering::AcqRel) {
+ return;
+ }
+ let handles = std::mem::take(
+ &mut *self
+ .inner
+ .observers
+ .lock()
+ .unwrap_or_else(std::sync::PoisonError::into_inner),
+ );
+ for handle in handles {
+ let _ = self.inner.adapter.core().unsubscribe(handle);
+ }
+ let _ = self.inner.adapter.sign_out();
+ }
+}
+
+fn closed_error() -> StudioError {
+ StudioError::Failure {
+ code: "InvalidApplicationState".to_owned(),
+ message: "The application runtime is closed.".to_owned(),
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use std::sync::{Arc, Mutex};
+
+ use radroots_studio_application::RelayConfiguration;
+ use radroots_studio_storage::PersistentAppCore;
+
+ use crate::commands::{RuntimeCore, SystemClock};
+ use crate::{AppSnapshotDto, StudioAppCore, StudioObserver};
+
+ #[derive(Default)]
+ struct RecordingObserver {
+ snapshots: Mutex<Vec<AppSnapshotDto>>,
+ core: Mutex<Option<Arc<StudioAppCore>>>,
+ }
+
+ impl StudioObserver for RecordingObserver {
+ fn on_snapshot_changed(&self, snapshot: AppSnapshotDto) {
+ if let Some(core) = self.core.lock().expect("core").as_ref() {
+ assert_eq!(core.snapshot().revision, snapshot.revision);
+ }
+ self.snapshots.lock().expect("snapshots").push(snapshot);
+ }
+ }
+
+ fn core() -> Arc<StudioAppCore> {
+ Arc::new(StudioAppCore {
+ inner: Arc::new(RuntimeCore {
+ adapter: PersistentAppCore::in_memory(RelayConfiguration::default()).expect("core"),
+ secrets: radroots_studio_storage::OsKeyringSecretStore,
+ clock: SystemClock,
+ nostr: radroots_studio_application::SdkNostrClient::new(
+ std::time::Duration::from_millis(10),
+ ),
+ observers: Mutex::new(std::collections::BTreeSet::new()),
+ closed: std::sync::atomic::AtomicBool::new(false),
+ }),
+ })
+ }
+
+ #[test]
+ fn callbacks_allow_reentry_and_stop_after_subscription_close() {
+ let core = core();
+ core.inner.adapter.core().bootstrap().expect("bootstrap");
+ let observer = Arc::new(RecordingObserver::default());
+ *observer.core.lock().expect("core") = Some(Arc::clone(&core));
+ let subscription = core
+ .subscribe(Box::new(ArcObserver(observer.clone())))
+ .expect("subscribe");
+
+ assert_eq!(observer.snapshots.lock().expect("snapshots").len(), 1);
+ core.inner
+ .adapter
+ .core()
+ .bootstrap()
+ .expect("idempotent bootstrap");
+ assert_eq!(observer.snapshots.lock().expect("snapshots").len(), 1);
+ subscription.close();
+ core.inner.adapter.core().sign_out().expect("sign out");
+ assert_eq!(observer.snapshots.lock().expect("snapshots").len(), 1);
+ }
+
+ #[test]
+ fn core_close_deregisters_all_observers_and_rejects_new_subscriptions() {
+ let core = core();
+ core.inner.adapter.core().bootstrap().expect("bootstrap");
+ let observer = Arc::new(RecordingObserver::default());
+ let _subscription = core
+ .subscribe(Box::new(ArcObserver(observer.clone())))
+ .expect("subscribe");
+
+ core.close();
+ core.close();
+
+ assert!(core.subscribe(Box::new(ArcObserver(observer))).is_err());
+ assert!(core.inner.observers.lock().expect("observers").is_empty());
+ }
+
+ struct ArcObserver(Arc<RecordingObserver>);
+
+ impl StudioObserver for ArcObserver {
+ fn on_snapshot_changed(&self, snapshot: AppSnapshotDto) {
+ self.0.on_snapshot_changed(snapshot);
+ }
+ }
+}
diff --git a/docs/implementation/nostr-runtime-rcld.md b/docs/implementation/nostr-runtime-rcld.md
@@ -523,7 +523,7 @@ handoff commit sequence.
- [x] 41. Create UniFFI scaffolding and DTO mapping.
- [x] 42. Expose approved AppCore commands through UniFFI.
-- [ ] 43. Expose observer callback and deregistration through UniFFI.
+- [x] 43. Expose observer callback and deregistration through UniFFI.
- [ ] 44. Build native library artifacts from Cargo.
- [ ] 45. Add Gradle task for Cargo build.
- [ ] 46. Add Gradle UniFFI binding generation and generated source set.
