tools_kit/toolset.rs
1use std::{
2 future::Future,
3 pin::Pin,
4 sync::{Arc, Mutex},
5 task::{Context, Poll},
6};
7use tokio::sync::{Notify, watch};
8use tokio::task::JoinHandle;
9
10use crate::{
11 ToolError, ToolHandler,
12 declaration::ToolInfo,
13 local::ToolRegistration,
14 mcp::McpClientConfig,
15 name::ToolName,
16 sources::{local::LocalToolset, mcp::McpToolset},
17};
18
19/// Public implementation contract for one shared executable tool source.
20/// Use this trait directly with concrete caller implementations and their exact
21/// associated handlers. [`Toolset::from_backend`] is optional normalization when a
22/// supplied Toolset is needed. Shared shutdown obligations apply to both forms.
23///
24/// # Examples
25///
26/// ```
27///
28/// # #[tokio::main(flavor = "current_thread")]
29/// # async fn main() -> Result<(), tools_kit::ToolError> {
30/// use tools_kit::{Toolset, ToolsetBackend};
31/// let tools = Toolset::local(Vec::new())?;
32/// assert!(tools.list_tools().await?.is_empty());
33/// tools.shutdown().await?;
34///
35/// # Ok(())
36/// # }
37/// ```
38///
39/// # Implement an executable caller Toolset
40///
41/// This runnable caller implementation executes a bounded string echo without tasks,
42/// networking, or asynchronous cleanup. It has one unique terminal handler per call,
43/// validates its advertised input shape itself, and seals root/handler admission on
44/// shared shutdown. More complex implementations must own accepted asynchronous work
45/// independently of a shutdown waiter. Neither this Toolset nor its Handler is Clone.
46///
47/// Direct use keeps the concrete associated child. Moving the same Toolset into
48/// [`Toolset::from_backend`] is optional; normalization does not supply missing
49/// backend validation, cancellation, or lifecycle behavior.
50///
51/// ```
52/// use std::sync::{Arc, atomic::{AtomicBool, Ordering}};
53/// use tools_kit::{ToolError, ToolHandlerBackend, Toolset, ToolsetBackend};
54/// use tools_kit::declaration::{ToolInfo, ToolName};
55/// use tools_kit::execution::{ToolContent, ToolHandlerInput, ToolHandlerOutput, ToolInvocation, ToolResult};
56/// use tools_kit::schema::JsonSchema;
57///
58/// struct EchoTools { info: ToolInfo, closed: Arc<AtomicBool> }
59/// struct EchoHandler { name: ToolName, closed: Arc<AtomicBool>, terminal: bool }
60/// impl EchoTools {
61/// fn check(&self) -> Result<(), ToolError> {
62/// if self.closed.load(Ordering::SeqCst) {
63/// return Err(ToolError::Closed { operation: "echo toolset".into() });
64/// }
65/// Ok(())
66/// }
67/// }
68/// impl ToolsetBackend for EchoTools {
69/// type Handler = EchoHandler;
70/// async fn list_tools(&self) -> Result<Vec<ToolInfo>, ToolError> {
71/// self.check()?;
72/// Ok(vec![self.info.clone()])
73/// }
74/// async fn tool_handler(&self, name: ToolName) -> Result<EchoHandler, ToolError> {
75/// self.check()?;
76/// if name != self.info.name { return Err(ToolError::UnknownTool { name }); }
77/// Ok(EchoHandler { name, closed: Arc::clone(&self.closed), terminal: false })
78/// }
79/// async fn shutdown(&self) -> Result<(), ToolError> {
80/// // No await: this synchronous toolset owns no unfinished external work.
81/// self.closed.store(true, Ordering::SeqCst);
82/// Ok(())
83/// }
84/// }
85/// impl ToolHandlerBackend for EchoHandler {
86/// async fn step(&mut self, input: ToolHandlerInput) -> Result<ToolHandlerOutput, ToolError> {
87/// if self.closed.load(Ordering::SeqCst) {
88/// return Err(ToolError::Closed { operation: "echo step".into() });
89/// }
90/// if self.terminal {
91/// return Err(ToolError::Protocol { message: "handler already terminal".into() });
92/// }
93/// match input {
94/// ToolHandlerInput::Invoke(invocation) => {
95/// let Some(text) = invocation.arguments.as_str().filter(|text| text.chars().count() <= 1024) else {
96/// return Err(ToolError::InvalidArguments {
97/// tool: self.name.clone(), message: "expected a string of at most 1024 characters".into(), issues: Vec::new(),
98/// });
99/// };
100/// self.terminal = true;
101/// Ok(ToolHandlerOutput::Completed(ToolResult::text(text)))
102/// }
103/// ToolHandlerInput::Cancel { reason } => {
104/// self.terminal = true;
105/// Err(ToolError::Cancelled { tool: self.name.clone(), reason })
106/// }
107/// ToolHandlerInput::Interaction(_) => Err(ToolError::Protocol {
108/// message: "this tool never requests interaction".into(),
109/// }),
110/// }
111/// }
112/// }
113///
114/// # #[tokio::main(flavor = "current_thread")]
115/// # async fn main() -> Result<(), ToolError> {
116/// let name = ToolName::new("echo")?;
117/// let concrete = EchoTools {
118/// info: ToolInfo::new(name.clone(), JsonSchema::strict(serde_json::json!({"type":"string","maxLength":1024}))),
119/// closed: Arc::new(AtomicBool::new(false)),
120/// };
121/// let mut direct = concrete.tool_handler(name.clone()).await?;
122/// let input = ToolInvocation { call_id: Some("call-1".into()), arguments: serde_json::json!("unchanged") };
123/// let ToolHandlerOutput::Completed(result) = direct.step(ToolHandlerInput::Invoke(input.clone())).await?
124/// else { panic!("echo does not interact") };
125/// assert!(!result.is_error);
126/// assert!(matches!(result.content.as_slice(), [ToolContent::Text { text, .. }] if text == "unchanged"));
127/// assert!(direct.step(ToolHandlerInput::Invoke(input.clone())).await.is_err());
128/// let tools = Toolset::from_backend(concrete); // Sole public erased ingress.
129/// let mut normalized = tools.tool_handler(name).await?;
130/// let observed = normalized.step(ToolHandlerInput::Invoke(input)).await;
131/// let cleanup = tools.shutdown().await;
132/// let ToolHandlerOutput::Completed(result) = observed? else { panic!("echo does not interact") };
133/// assert!(matches!(result.content.as_slice(), [ToolContent::Text { text, .. }] if text == "unchanged"));
134/// cleanup?;
135/// assert!(tools.list_tools().await.is_err());
136/// tools.shutdown().await?;
137/// # Ok(())
138/// # }
139/// ```
140///
141pub trait ToolsetBackend: Send + Sync + 'static {
142 /// Unique resumable handler produced by this tool source.
143 type Handler: crate::ToolHandlerBackend;
144
145 /// Lists the complete executable inventory.
146 ///
147 /// # Errors
148 ///
149 /// Returns [`ToolError::Closed`] after sealing, or the underlying inventory failure.
150 ///
151 /// # Examples
152 ///
153 /// ```
154 ///
155 /// # #[tokio::main(flavor = "current_thread")]
156 /// # async fn main() -> Result<(), tools_kit::ToolError> {
157 /// use tools_kit::{Toolset, ToolsetBackend};
158 /// let tools = Toolset::local(Vec::new())?;
159 /// assert!(tools.list_tools().await?.is_empty());
160 /// tools.shutdown().await?;
161 ///
162 /// # Ok(())
163 /// # }
164 /// ```
165 ///
166 fn list_tools(&self) -> impl Future<Output = Result<Vec<ToolInfo>, ToolError>> + Send + '_;
167
168 /// Creates a unique handler for one selected tool name.
169 ///
170 /// # Errors
171 ///
172 /// Returns an unknown-name error when no declared tool matches, [`ToolError::Closed`] after sealing, or the underlying handler-construction failure.
173 ///
174 /// # Examples
175 ///
176 /// ```
177 ///
178 /// # #[tokio::main(flavor = "current_thread")]
179 /// # async fn main() -> Result<(), tools_kit::ToolError> {
180 /// use tools_kit::{declaration::{ToolInfo, ToolName}, schema::JsonSchema};
181 /// let info = ToolInfo::new(ToolName::new("ping")?, JsonSchema::strict(serde_json::json!({"type":"object"})));
182 /// use tools_kit::{local::ToolRegistration, execution::ToolResult};
183 /// let registration = ToolRegistration::function(info, |_| async { Ok(ToolResult::text("pong")) });
184 /// use tools_kit::{Toolset, ToolsetBackend, ToolHandlerBackend, execution::{ToolHandlerInput, ToolHandlerOutput, ToolInvocation}};
185 /// let tools = Toolset::local(vec![registration])?;
186 /// let mut handler = tools.tool_handler(ToolName::new("ping")?).await?;
187 /// let result = handler.step(ToolHandlerInput::Invoke(ToolInvocation { call_id: None, arguments: serde_json::json!({}) })).await;
188 /// let cleanup = tools.shutdown().await;
189 /// assert!(matches!(result?, ToolHandlerOutput::Completed(_)));
190 /// cleanup?;
191 ///
192 /// # Ok(())
193 /// # }
194 /// ```
195 ///
196 fn tool_handler(
197 &self,
198 name: ToolName,
199 ) -> impl Future<Output = Result<Self::Handler, ToolError>> + Send + '_;
200
201 /// Seals admission and performs shared exactly-once cleanup.
202 ///
203 /// This contract applies to direct caller implementations as well as supplied
204 /// handles. On first acceptance, retain and track the cleanup independently of
205 /// this awaiting future. Dropping a shutdown waiter or the last public value
206 /// must not abandon accepted cleanup. Repeated calls observe its terminal
207 /// result; they must not start another cleanup. Listing and handler admission
208 /// reject after sealing. A consumer may bound its wait with a deadline, so
209 /// putting all cleanup solely inside this borrowed future is insufficient.
210 ///
211 /// # Errors
212 ///
213 /// Replays the shared cleanup error, including a cleanup timeout, to concurrent and later callers. A failed observation does not authorize abandoning accepted cleanup.
214 ///
215 /// # Examples
216 ///
217 /// ```
218 ///
219 /// # #[tokio::main(flavor = "current_thread")]
220 /// # async fn main() -> Result<(), tools_kit::ToolError> {
221 /// use tools_kit::{Toolset, ToolsetBackend};
222 /// let tools = Toolset::local(Vec::new())?;
223 /// let shared = tools.clone();
224 /// tools.shutdown().await?;
225 /// shared.shutdown().await?;
226 /// assert!(shared.list_tools().await.is_err());
227 ///
228 /// # Ok(())
229 /// # }
230 /// ```
231 ///
232 fn shutdown(&self) -> impl Future<Output = Result<(), ToolError>> + Send + '_;
233}
234
235/// Opaque cloneable Toolset over Local, MCP, or downstream behavior.
236/// Clones share admission and cleanup. Dropping a clone alone does not initiate
237/// asynchronous cleanup; explicitly await [`ToolsetBackend::shutdown`].
238///
239/// # Examples
240///
241/// ```
242///
243/// # #[tokio::main(flavor = "current_thread")]
244/// # async fn main() -> Result<(), tools_kit::ToolError> {
245/// use tools_kit::{Toolset, ToolsetBackend};
246/// let tools = Toolset::local(Vec::new())?;
247/// assert!(tools.list_tools().await?.is_empty());
248/// tools.shutdown().await?;
249///
250/// # Ok(())
251/// # }
252/// ```
253///
254#[derive(Clone)]
255pub struct Toolset {
256 runtime: Arc<ToolsetRuntime>,
257}
258
259struct ToolsetRuntime {
260 backend: InnerToolset,
261 lifecycle: ToolsetLifecycle,
262}
263
264enum InnerToolset {
265 Local(LocalToolset),
266 Mcp(McpToolset),
267 Extension(Arc<dyn ErasedToolsetBackend>),
268}
269
270impl Toolset {
271 /// Builds an in-process Toolset from complete registrations.
272 ///
273 /// # Errors
274 ///
275 /// Returns [`ToolError::DuplicateName`] for duplicate names; an empty inventory is valid.
276 ///
277 /// # Examples
278 ///
279 /// ```
280 ///
281 /// # #[tokio::main(flavor = "current_thread")]
282 /// # async fn main() -> Result<(), tools_kit::ToolError> {
283 /// use tools_kit::{Toolset, ToolsetBackend};
284 /// let tools = Toolset::local(Vec::new())?;
285 /// assert!(tools.list_tools().await?.is_empty());
286 /// tools.shutdown().await?;
287 ///
288 /// # Ok(())
289 /// # }
290 /// ```
291 ///
292 pub fn local(registrations: Vec<ToolRegistration>) -> Result<Self, ToolError> {
293 Ok(Self::from_local(LocalToolset::build(registrations)?))
294 }
295
296 /// Connects one MCP client Toolset and discovers its inventory.
297 /// This example requires a running MCP service at the configured endpoint.
298 ///
299 /// # Errors
300 ///
301 /// Returns [`ToolError`] for invalid connection settings, process startup, transport or initialization failure, malformed inventory, or an elapsed request deadline.
302 ///
303 /// # Examples
304 ///
305 /// ```no_run
306 ///
307 /// # #[tokio::main(flavor = "current_thread")]
308 /// # async fn main() -> Result<(), tools_kit::ToolError> {
309 /// use tools_kit::mcp::{McpClientConfig, McpConnectionConfig};
310 /// let connection = McpConnectionConfig::StreamableHttp { endpoint: "http://127.0.0.1:8000/mcp".parse().unwrap(), headers: Default::default() };
311 /// let config = McpClientConfig::new(connection);
312 /// use tools_kit::{Toolset, ToolsetBackend};
313 /// let tools = Toolset::mcp(config).await?;
314 /// let inventory = tools.list_tools().await;
315 /// let cleanup = tools.shutdown().await;
316 /// let _ = inventory?;
317 /// cleanup?;
318 ///
319 /// # Ok(())
320 /// # }
321 /// ```
322 ///
323 pub async fn mcp(config: McpClientConfig) -> Result<Self, ToolError> {
324 Ok(Self::from_mcp(McpToolset::connect(config).await?))
325 }
326
327 /// Wraps a downstream Toolset implementation.
328 /// The associated handler is normalized privately. Concrete callers may instead
329 /// retain the backend directly; there is no public child normalization constructor.
330 ///
331 /// # Examples
332 ///
333 /// ```
334 ///
335 /// # #[tokio::main(flavor = "current_thread")]
336 /// # async fn main() -> Result<(), tools_kit::ToolError> {
337 /// use std::sync::atomic::{AtomicBool, Ordering};
338 /// use tools_kit::{ToolError, Toolset, ToolsetBackend, ToolHandlerBackend};
339 /// use tools_kit::declaration::{ToolInfo, ToolName};
340 /// use tools_kit::execution::{ToolHandlerInput, ToolHandlerOutput};
341 /// struct EmptyInventory { closed: AtomicBool }
342 /// enum NoHandler {}
343 /// impl ToolHandlerBackend for NoHandler {
344 /// async fn step(&mut self, _: ToolHandlerInput) -> Result<ToolHandlerOutput, ToolError> {
345 /// match *self {}
346 /// }
347 /// }
348 /// impl ToolsetBackend for EmptyInventory {
349 /// type Handler = NoHandler;
350 /// async fn list_tools(&self) -> Result<Vec<ToolInfo>, ToolError> {
351 /// if self.closed.load(Ordering::Acquire) {
352 /// return Err(ToolError::Closed { operation: "list_tools".into() });
353 /// }
354 /// Ok(Vec::new())
355 /// }
356 /// async fn tool_handler(&self, name: ToolName) -> Result<NoHandler, ToolError> {
357 /// if self.closed.load(Ordering::Acquire) {
358 /// return Err(ToolError::Closed { operation: "tool_handler".into() });
359 /// }
360 /// Err(ToolError::UnknownTool { name })
361 /// }
362 /// async fn shutdown(&self) -> Result<(), ToolError> {
363 /// self.closed.store(true, Ordering::Release);
364 /// Ok(()) // This empty implementation owns no asynchronous resources.
365 /// }
366 /// }
367 /// let concrete = EmptyInventory { closed: AtomicBool::new(false) };
368 /// assert!(concrete.list_tools().await?.is_empty());
369 /// let normalized = Toolset::from_backend(concrete);
370 /// normalized.shutdown().await?;
371 /// assert!(normalized.list_tools().await.is_err());
372 ///
373 /// # Ok(())
374 /// # }
375 /// ```
376 ///
377 #[must_use]
378 pub fn from_backend<B: ToolsetBackend>(backend: B) -> Self {
379 Self {
380 runtime: Arc::new(ToolsetRuntime::new(InnerToolset::Extension(Arc::new(
381 backend,
382 )))),
383 }
384 }
385
386 fn from_local(toolset: LocalToolset) -> Self {
387 Self {
388 runtime: Arc::new(ToolsetRuntime::new(InnerToolset::Local(toolset))),
389 }
390 }
391
392 fn from_mcp(toolset: McpToolset) -> Self {
393 Self {
394 runtime: Arc::new(ToolsetRuntime::new(InnerToolset::Mcp(toolset))),
395 }
396 }
397}
398
399impl std::fmt::Debug for Toolset {
400 fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
401 formatter.debug_struct("Toolset").finish_non_exhaustive()
402 }
403}
404
405trait ErasedToolsetBackend: Send + Sync {
406 fn list_tools_erased(
407 &self,
408 ) -> Pin<Box<dyn Future<Output = Result<Vec<ToolInfo>, ToolError>> + Send + '_>>;
409
410 fn tool_handler_erased(
411 &self,
412 name: ToolName,
413 ) -> Pin<Box<dyn Future<Output = Result<ToolHandler, ToolError>> + Send + '_>>;
414
415 fn shutdown_erased(&self) -> Pin<Box<dyn Future<Output = Result<(), ToolError>> + Send + '_>>;
416}
417
418impl<B: ToolsetBackend> ErasedToolsetBackend for B {
419 fn list_tools_erased(
420 &self,
421 ) -> Pin<Box<dyn Future<Output = Result<Vec<ToolInfo>, ToolError>> + Send + '_>> {
422 Box::pin(self.list_tools())
423 }
424
425 fn tool_handler_erased(
426 &self,
427 name: ToolName,
428 ) -> Pin<Box<dyn Future<Output = Result<ToolHandler, ToolError>> + Send + '_>> {
429 Box::pin(async move {
430 self.tool_handler(name)
431 .await
432 .map(ToolHandler::from_extension)
433 })
434 }
435
436 fn shutdown_erased(&self) -> Pin<Box<dyn Future<Output = Result<(), ToolError>> + Send + '_>> {
437 Box::pin(self.shutdown())
438 }
439}
440
441impl ToolsetBackend for InnerToolset {
442 type Handler = ToolHandler;
443
444 async fn list_tools(&self) -> Result<Vec<ToolInfo>, ToolError> {
445 match self {
446 Self::Local(toolset) => toolset.list_tools().await,
447 Self::Mcp(toolset) => toolset.list_tools().await,
448 Self::Extension(toolset) => toolset.list_tools_erased().await,
449 }
450 }
451
452 async fn tool_handler(&self, name: ToolName) -> Result<Self::Handler, ToolError> {
453 match self {
454 Self::Local(toolset) => toolset
455 .tool_handler(name)
456 .await
457 .map(ToolHandler::from_local),
458 Self::Mcp(toolset) => toolset.tool_handler(name).await.map(ToolHandler::from_mcp),
459 Self::Extension(toolset) => toolset.tool_handler_erased(name).await,
460 }
461 }
462
463 async fn shutdown(&self) -> Result<(), ToolError> {
464 match self {
465 Self::Local(toolset) => toolset.shutdown().await,
466 Self::Mcp(toolset) => toolset.shutdown().await,
467 Self::Extension(toolset) => toolset.shutdown_erased().await,
468 }
469 }
470}
471
472impl ToolsetBackend for Toolset {
473 type Handler = ToolHandler;
474
475 async fn list_tools(&self) -> Result<Vec<ToolInfo>, ToolError> {
476 let _admission = self.runtime.admit("list_tools")?;
477 self.runtime.backend.list_tools().await
478 }
479
480 async fn tool_handler(&self, name: ToolName) -> Result<Self::Handler, ToolError> {
481 let _admission = self.runtime.admit("tool_handler")?;
482 self.runtime.backend.tool_handler(name).await
483 }
484
485 async fn shutdown(&self) -> Result<(), ToolError> {
486 self.runtime.shutdown().await
487 }
488}
489
490struct ToolsetLifecycle {
491 state: Mutex<ToolsetState>,
492 changed: Notify,
493}
494
495enum ToolsetState {
496 Open {
497 admitted: usize,
498 },
499 Closing {
500 admitted: usize,
501 completion: watch::Receiver<Option<Result<(), ToolError>>>,
502 task: JoinHandle<()>,
503 },
504 Closed {
505 terminal: Result<(), ToolError>,
506 },
507}
508
509struct ToolsetAdmission {
510 runtime: Arc<ToolsetRuntime>,
511}
512
513impl ToolsetRuntime {
514 fn new(backend: InnerToolset) -> Self {
515 Self {
516 backend,
517 lifecycle: ToolsetLifecycle {
518 state: Mutex::new(ToolsetState::Open { admitted: 0 }),
519 changed: Notify::new(),
520 },
521 }
522 }
523
524 fn admit(self: &Arc<Self>, operation: &'static str) -> Result<ToolsetAdmission, ToolError> {
525 let mut state = self.lifecycle.state();
526 match &mut *state {
527 ToolsetState::Open { admitted } => {
528 *admitted = admitted
529 .checked_add(1)
530 .ok_or_else(|| ToolError::Transport {
531 tool: None,
532 message: "toolset admission is exhausted".to_owned(),
533 })?;
534 Ok(ToolsetAdmission {
535 runtime: Arc::clone(self),
536 })
537 }
538 ToolsetState::Closing { .. } | ToolsetState::Closed { .. } => {
539 Err(ToolError::closed(operation))
540 }
541 }
542 }
543
544 async fn shutdown(self: &Arc<Self>) -> Result<(), ToolError> {
545 self.start_shutdown()?;
546 self.lifecycle.terminal().await
547 }
548
549 fn start_shutdown(self: &Arc<Self>) -> Result<(), ToolError> {
550 let mut state = self.lifecycle.state();
551 let admitted = match &*state {
552 ToolsetState::Open { admitted } => *admitted,
553 ToolsetState::Closing { .. } | ToolsetState::Closed { .. } => return Ok(()),
554 };
555 let handle = tokio::runtime::Handle::try_current().map_err(|_| ToolError::Transport {
556 tool: None,
557 message: "toolset shutdown requires a Tokio runtime".to_owned(),
558 })?;
559 let (terminal, completion) = watch::channel(None);
560 let runtime = Arc::clone(self);
561 let task = handle.spawn(async move {
562 terminal.send_replace(Some(runtime.finish_shutdown().await));
563 });
564 *state = ToolsetState::Closing {
565 admitted,
566 completion,
567 task,
568 };
569 Ok(())
570 }
571
572 async fn finish_shutdown(self: Arc<Self>) -> Result<(), ToolError> {
573 self.lifecycle.drain().await;
574 self.backend.shutdown().await
575 }
576}
577
578impl ToolsetLifecycle {
579 fn state(&self) -> std::sync::MutexGuard<'_, ToolsetState> {
580 self.state
581 .lock()
582 .unwrap_or_else(std::sync::PoisonError::into_inner)
583 }
584
585 fn release(&self) {
586 let should_notify = {
587 let mut state = self.state();
588 match &mut *state {
589 ToolsetState::Open { admitted } => {
590 debug_assert_ne!(*admitted, 0);
591 *admitted = admitted.saturating_sub(1);
592 false
593 }
594 ToolsetState::Closing { admitted, .. } => {
595 debug_assert_ne!(*admitted, 0);
596 *admitted = admitted.saturating_sub(1);
597 *admitted == 0
598 }
599 ToolsetState::Closed { .. } => {
600 debug_assert!(false, "closed toolset retained an admission");
601 false
602 }
603 }
604 };
605 if should_notify {
606 self.changed.notify_waiters();
607 }
608 }
609
610 async fn drain(&self) {
611 loop {
612 let notified = self.changed.notified();
613 tokio::pin!(notified);
614 notified.as_mut().enable();
615 let drained = match &*self.state() {
616 ToolsetState::Open { admitted } | ToolsetState::Closing { admitted, .. } => {
617 *admitted == 0
618 }
619 ToolsetState::Closed { .. } => true,
620 };
621 if drained {
622 return;
623 }
624 notified.await;
625 }
626 }
627
628 async fn terminal(&self) -> Result<(), ToolError> {
629 let mut completion = match &*self.state() {
630 ToolsetState::Closing { completion, .. } => completion.clone(),
631 ToolsetState::Closed { terminal } => return terminal.clone(),
632 ToolsetState::Open { .. } => {
633 return Err(ToolError::Transport {
634 tool: None,
635 message: "toolset shutdown lost lifecycle ownership".to_owned(),
636 });
637 }
638 };
639 let terminal = match completion.wait_for(Option::is_some).await {
640 Ok(terminal) => terminal
641 .as_ref()
642 .cloned()
643 .ok_or_else(|| ToolError::Transport {
644 tool: None,
645 message: "toolset shutdown result is unavailable".to_owned(),
646 })?,
647 Err(_) => Err(ToolError::Transport {
648 tool: None,
649 message: "toolset shutdown owner exited without a terminal result".to_owned(),
650 }),
651 };
652 loop {
653 let settled = {
654 let mut state = self.state();
655 match &mut *state {
656 ToolsetState::Closed { terminal } => return terminal.clone(),
657 ToolsetState::Closing { task, .. } if task.is_finished() => {
658 let waker = std::task::Waker::noop();
659 let mut context = Context::from_waker(waker);
660 match Pin::new(task).poll(&mut context) {
661 Poll::Ready(joined) => {
662 let terminal = if joined.is_ok() {
663 terminal.clone()
664 } else {
665 Err(ToolError::Transport {
666 tool: None,
667 message: "toolset shutdown owner could not be joined"
668 .to_owned(),
669 })
670 };
671 *state = ToolsetState::Closed {
672 terminal: terminal.clone(),
673 };
674 Some(terminal)
675 }
676 Poll::Pending => None,
677 }
678 }
679 ToolsetState::Closing { .. } => None,
680 ToolsetState::Open { .. } => {
681 let terminal = Err(ToolError::Transport {
682 tool: None,
683 message: "toolset shutdown lost lifecycle ownership".to_owned(),
684 });
685 *state = ToolsetState::Closed {
686 terminal: terminal.clone(),
687 };
688 Some(terminal)
689 }
690 }
691 };
692 if let Some(terminal) = settled {
693 self.changed.notify_waiters();
694 return terminal;
695 }
696 tokio::task::yield_now().await;
697 }
698 }
699}
700
701impl Drop for ToolsetAdmission {
702 fn drop(&mut self) {
703 self.runtime.lifecycle.release();
704 }
705}