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lenso_kernel/
request.rs

1use std::{any::Any, time::Duration};
2
3use super::{
4    CancellationToken, EventCapability, InvocationContext, LocalBoxFuture, NativeAppRuntime,
5    NativeEndpointBinding, NativeEventHandle, NativeRequestEndpoint, NativeRequestHandle,
6    NativeStreamEndpointBinding, NativeStreamHandle, PluginEventDependencyHandle, Rc, RefCell,
7    StreamCapability, Weak,
8};
9
10pub trait RequestCapability: 'static {
11    /// Typed request value.
12    type Request: 'static;
13    /// Typed success value.
14    type Response: 'static;
15    /// Typed Capability-defined error value.
16    type DomainError: 'static;
17    /// Stable Capability series identity.
18    const ID: &'static str;
19    /// Exact generated Descriptor version.
20    const DESCRIPTOR_VERSION: &'static str;
21
22    /// Invokes one native endpoint using the most specific binding available.
23    ///
24    /// Generated bindings override this hook with a typed path. Older bindings retain the
25    /// type-erased compatibility path without requiring regeneration.
26    #[doc(hidden)]
27    fn invoke_native(
28        endpoint: &dyn NativeRequestEndpoint,
29        operation: &str,
30        request: Self::Request,
31        context: InvocationContext,
32    ) -> NativeRequestFuture<Self>
33    where
34        Self: Sized,
35    {
36        invoke_typed_or_erased_native_request::<Self>(endpoint, operation, request, context)
37    }
38}
39
40/// A typed native request result before Kernel cancellation and supervision are applied.
41#[doc(hidden)]
42pub type NativeRequestFuture<C> = LocalBoxFuture<
43    'static,
44    Result<
45        Result<<C as RequestCapability>::Response, <C as RequestCapability>::DomainError>,
46        RuntimeFailure,
47    >,
48>;
49
50type TypedNativeRequestFn<C> =
51    dyn Fn(&str, <C as RequestCapability>::Request, InvocationContext) -> NativeRequestFuture<C>;
52
53/// Runtime-provided typed endpoint used when a request crosses an execution boundary.
54///
55/// Generated in-process endpoints may expose a more specific endpoint type. This generic
56/// carrier lets execution adapters preserve typed request, response, and domain-error values
57/// without routing them through `Box<dyn Any>`.
58#[doc(hidden)]
59pub struct TypedNativeRequestEndpoint<C: RequestCapability> {
60    invoke: Rc<TypedNativeRequestFn<C>>,
61}
62
63impl<C: RequestCapability> TypedNativeRequestEndpoint<C> {
64    /// Creates a typed endpoint around one runtime-owned dispatcher.
65    pub fn new(
66        invoke: impl Fn(&str, C::Request, InvocationContext) -> NativeRequestFuture<C> + 'static,
67    ) -> Self {
68        Self {
69            invoke: Rc::new(invoke),
70        }
71    }
72
73    /// Dispatches one request without type erasure.
74    pub fn invoke(
75        &self,
76        operation: &str,
77        request: C::Request,
78        context: InvocationContext,
79    ) -> NativeRequestFuture<C> {
80        (self.invoke)(operation, request, context)
81    }
82}
83
84impl<C: RequestCapability> std::fmt::Debug for TypedNativeRequestEndpoint<C> {
85    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
86        formatter
87            .debug_struct("TypedNativeRequestEndpoint")
88            .field("capability", &C::ID)
89            .finish_non_exhaustive()
90    }
91}
92
93/// Uses a runtime-provided typed endpoint when present, retaining erased compatibility.
94#[doc(hidden)]
95pub fn invoke_typed_or_erased_native_request<C: RequestCapability>(
96    endpoint: &dyn NativeRequestEndpoint,
97    operation: &str,
98    request: C::Request,
99    context: InvocationContext,
100) -> NativeRequestFuture<C> {
101    if let Some(endpoint) = endpoint
102        .typed_endpoint()
103        .and_then(|endpoint| endpoint.downcast_ref::<TypedNativeRequestEndpoint<C>>())
104    {
105        endpoint.invoke(operation, request, context)
106    } else {
107        invoke_erased_native_request::<C>(endpoint, operation, request, context)
108    }
109}
110
111/// Compatibility dispatcher used by generated bindings when a typed endpoint is unavailable.
112#[doc(hidden)]
113pub fn invoke_erased_native_request<C: RequestCapability>(
114    endpoint: &dyn NativeRequestEndpoint,
115    operation: &str,
116    request: C::Request,
117    context: InvocationContext,
118) -> NativeRequestFuture<C> {
119    let invocation = endpoint.invoke(operation, Box::new(request), context);
120    Box::pin(async move {
121        match invocation.await? {
122            Ok(value) => value
123                .downcast::<C::Response>()
124                .map(|value| Ok(*value))
125                .map_err(|_| RuntimeFailure::ProtocolViolation { capability: C::ID }),
126            Err(value) => value
127                .downcast::<C::DomainError>()
128                .map(|value| Err(*value))
129                .map_err(|_| RuntimeFailure::ProtocolViolation { capability: C::ID }),
130        }
131    })
132}
133
134/// Kernel-generated identity for one logical request invocation.
135pub type RequestId = u64;
136
137/// Runtime-owned failure, kept separate from Capability-defined Domain Errors.
138#[derive(Clone, Debug, Eq, PartialEq)]
139pub enum RuntimeFailure {
140    /// The consumer has no resolved binding for this Capability.
141    Unavailable { capability: &'static str },
142    /// The bound provider does not declare the requested Operation.
143    UnknownOperation {
144        capability: &'static str,
145        operation: String,
146    },
147    /// A singular generated client was used for a requirement with many providers.
148    AmbiguousBinding {
149        capability: &'static str,
150        providers: usize,
151    },
152    /// Generated native types disagreed with the prepared endpoint.
153    ProtocolViolation { capability: &'static str },
154    /// A package selected by the Plan was not linked into the native App.
155    MissingPluginFactory {
156        instance: String,
157        package_id: String,
158    },
159    /// No installed Execution Adapter provides the class selected by one Instance.
160    UnavailableExecutionClass {
161        instance_key: String,
162        execution_class: String,
163    },
164    /// The Resolved Plan or prepared endpoint set is internally inconsistent.
165    InvalidResolvedPlan { detail: String },
166    /// New request admission was closed because the App is shutting down.
167    AdmissionClosed,
168    /// The request could not enter a full bounded admission queue.
169    ResourceExhausted {
170        capability: &'static str,
171        operation: String,
172    },
173    /// The invocation deadline expired before the request completed.
174    DeadlineExceeded { request_id: RequestId },
175    /// The caller cancelled the invocation before it completed.
176    Cancelled { request_id: RequestId },
177    /// The Runtime Driver or Adapter reported an internal execution failure.
178    Internal { detail: String },
179    /// A Plugin generation reported a failure that should trigger supervision.
180    PluginFailure { detail: String },
181    /// A Plugin Instance exhausted its finite restart budget.
182    PluginRestartExhausted { instance: String, attempts: usize },
183}
184
185/// The lifecycle phase represented by a Plugin context.
186#[derive(Clone, Copy, Debug, Eq, PartialEq)]
187pub enum PluginLifecyclePhase {
188    /// The Plugin may validate configuration and reserve reversible resources.
189    Prepare,
190    /// Adapter lowering constructs the complete inert Plugin object.
191    Construct,
192    /// The Plugin may initialize against already prepared dependencies.
193    Activate,
194    /// The App Ready Gate has opened and externally triggered work may begin.
195    Ready,
196    /// The Plugin must release work and resources owned by this generation.
197    Deactivate,
198}
199
200#[cfg(test)]
201mod typed_endpoint_tests {
202    use std::any::Any;
203
204    use super::*;
205
206    #[derive(Debug)]
207    struct Echo;
208
209    impl RequestCapability for Echo {
210        type Request = u64;
211        type Response = u64;
212        type DomainError = ();
213        const ID: &'static str = "test.echo@1";
214        const DESCRIPTOR_VERSION: &'static str = "1.0.0";
215    }
216
217    #[derive(Debug)]
218    struct Endpoint {
219        typed: TypedNativeRequestEndpoint<Echo>,
220    }
221
222    impl NativeRequestEndpoint for Endpoint {
223        fn capability_id(&self) -> &'static str {
224            Echo::ID
225        }
226
227        fn descriptor_version(&self) -> &'static str {
228            Echo::DESCRIPTOR_VERSION
229        }
230
231        fn operations(&self) -> &'static [&'static str] {
232            &["echo"]
233        }
234
235        fn typed_endpoint(&self) -> Option<&dyn Any> {
236            Some(&self.typed)
237        }
238
239        fn invoke(
240            &self,
241            _operation: &str,
242            _request: Box<dyn Any>,
243            _context: InvocationContext,
244        ) -> LocalBoxFuture<'static, Result<crate::ErasedDomainResult, RuntimeFailure>> {
245            panic!("typed dispatch must not call the erased endpoint")
246        }
247    }
248
249    #[test]
250    fn default_dispatch_uses_runtime_typed_endpoint() {
251        let endpoint = Endpoint {
252            typed: TypedNativeRequestEndpoint::new(|_, request, _| {
253                Box::pin(futures::future::ready(Ok(Ok(request + 1))))
254            }),
255        };
256        let context = InvocationContext::new(1, None, CancellationToken::new());
257
258        let result =
259            futures::executor::block_on(Echo::invoke_native(&endpoint, "echo", 41, context));
260
261        assert_eq!(result, Ok(Ok(42)));
262    }
263}
264
265/// A deterministic dependency visible to one Plugin Instance.
266#[derive(Clone, Debug)]
267pub struct PluginDependency {
268    pub(super) requirement_id: String,
269    pub(super) capability_id: String,
270    pub(super) provider_instance: String,
271    pub(super) provider_order: usize,
272    pub(super) handle: Option<PluginDependencyHandle>,
273    pub(super) stream_handle: Option<PluginStreamDependencyHandle>,
274    pub(super) event_handle: Option<PluginEventDependencyHandle>,
275}
276
277impl PluginDependency {
278    pub(super) fn new(
279        requirement_id: impl Into<String>,
280        capability_id: impl Into<String>,
281        provider_instance: impl Into<String>,
282        provider_order: usize,
283        handle: Option<PluginDependencyHandle>,
284        stream_handle: Option<PluginStreamDependencyHandle>,
285        event_handle: Option<PluginEventDependencyHandle>,
286    ) -> Self {
287        Self {
288            requirement_id: requirement_id.into(),
289            capability_id: capability_id.into(),
290            provider_instance: provider_instance.into(),
291            provider_order,
292            handle,
293            stream_handle,
294            event_handle,
295        }
296    }
297
298    /// Returns the Capability required by this dependency.
299    pub fn requirement_id(&self) -> &str {
300        &self.requirement_id
301    }
302
303    /// Returns the Capability required by this dependency.
304    pub fn capability_id(&self) -> &str {
305        &self.capability_id
306    }
307
308    /// Returns the App-local provider Instance key.
309    pub fn provider_instance(&self) -> &str {
310        &self.provider_instance
311    }
312
313    /// Returns the deterministic provider order for a `many` binding.
314    pub const fn provider_order(&self) -> usize {
315        self.provider_order
316    }
317
318    /// Returns the resolved native endpoint handle when the Adapter supplied one.
319    pub fn handle(&self) -> Option<PluginDependencyHandle> {
320        self.handle.clone()
321    }
322
323    /// Returns the resolved native stream endpoint handle when the Adapter supplied one.
324    pub fn stream_handle(&self) -> Option<PluginStreamDependencyHandle> {
325        self.stream_handle.clone()
326    }
327
328    /// Returns the resolved native Event endpoint handle when the Adapter supplied one.
329    pub fn event_handle(&self) -> Option<PluginEventDependencyHandle> {
330        self.event_handle.clone()
331    }
332}
333
334/// An opaque, Adapter-resolved Capability endpoint passed to lifecycle code.
335#[derive(Clone, Debug)]
336pub struct PluginDependencyHandle {
337    pub(super) binding: NativeEndpointBinding,
338    pub(super) caller_instance: String,
339    pub(super) runtime: Rc<RefCell<Weak<NativeAppRuntime>>>,
340}
341
342/// An opaque, Adapter-resolved stream Capability endpoint passed to lifecycle code.
343#[derive(Clone, Debug)]
344pub struct PluginStreamDependencyHandle {
345    pub(super) binding: NativeStreamEndpointBinding,
346    pub(super) caller_instance: String,
347    pub(super) runtime: Rc<RefCell<Weak<NativeAppRuntime>>>,
348}
349
350impl PluginStreamDependencyHandle {
351    /// Returns the Capability implemented by this stream handle.
352    pub fn capability_id(&self) -> &'static str {
353        self.binding.state.capability_id
354    }
355
356    /// Returns the exact Descriptor version implemented by this stream handle.
357    pub fn descriptor_version(&self) -> &'static str {
358        self.binding.state.descriptor_version
359    }
360
361    /// Returns the exact stream Operation table implemented by this handle.
362    pub fn operations(&self) -> &'static [&'static str] {
363        self.binding.state.operations
364    }
365
366    /// Converts this resolved dependency into its generated typed stream handle.
367    pub fn typed<C: StreamCapability>(&self) -> Result<NativeStreamHandle<C>, RuntimeFailure> {
368        if self.capability_id() != C::ID || self.descriptor_version() != C::DESCRIPTOR_VERSION {
369            return Err(RuntimeFailure::ProtocolViolation { capability: C::ID });
370        }
371        let runtime = self
372            .runtime
373            .borrow()
374            .upgrade()
375            .ok_or(RuntimeFailure::AdmissionClosed)?;
376        Ok(NativeStreamHandle::from_endpoints(
377            std::slice::from_ref(&self.binding),
378            runtime,
379            &self.caller_instance,
380            true,
381        ))
382    }
383}
384
385impl PluginDependencyHandle {
386    /// Returns the Capability implemented by this handle.
387    pub fn capability_id(&self) -> &'static str {
388        self.binding.state.capability_id
389    }
390
391    /// Returns the exact Descriptor version implemented by this handle.
392    pub fn descriptor_version(&self) -> &'static str {
393        self.binding.state.descriptor_version
394    }
395
396    /// Returns the exact Operation table implemented by this handle.
397    pub fn operations(&self) -> &'static [&'static str] {
398        self.binding.state.operations
399    }
400
401    /// Invokes this exact resolved dependency through Kernel admission and supervision.
402    ///
403    /// Language Execution Adapters use this after their generated codec has decoded a
404    /// portable request into the provider's native erased value.
405    pub fn invoke_erased(
406        &self,
407        operation: &str,
408        request: Box<dyn Any>,
409        context: InvocationContext,
410    ) -> LocalBoxFuture<'static, Result<crate::ErasedDomainResult, RuntimeFailure>> {
411        let Some(runtime) = self.runtime.borrow().upgrade() else {
412            return Box::pin(futures::future::ready(Err(RuntimeFailure::AdmissionClosed)));
413        };
414        crate::request_handle::invoke_erased_dependency(
415            self.binding.clone(),
416            runtime,
417            self.caller_instance.clone(),
418            operation.to_owned(),
419            context,
420            request,
421        )
422    }
423
424    /// Converts this resolved dependency into its generated typed request handle.
425    pub fn typed<C: RequestCapability>(&self) -> Result<NativeRequestHandle<C>, RuntimeFailure> {
426        if self.capability_id() != C::ID || self.descriptor_version() != C::DESCRIPTOR_VERSION {
427            return Err(RuntimeFailure::ProtocolViolation { capability: C::ID });
428        }
429        let runtime = self
430            .runtime
431            .borrow()
432            .upgrade()
433            .ok_or(RuntimeFailure::AdmissionClosed)?;
434        Ok(NativeRequestHandle::from_endpoints(
435            std::slice::from_ref(&self.binding),
436            runtime,
437            &self.caller_instance,
438            true,
439        ))
440    }
441}
442
443/// The explicit Capability dependencies available during Plugin lifecycle.
444#[derive(Clone, Debug, Default)]
445pub struct PluginDependencies {
446    pub(super) requirements: Vec<lenso_app_plan::CapabilityRequirementPlan>,
447    pub(super) bindings: Vec<PluginDependency>,
448    pub(super) caller_instance: Rc<str>,
449    pub(super) runtime: Rc<RefCell<Weak<NativeAppRuntime>>>,
450}
451
452impl PluginDependencies {
453    pub(super) fn new(
454        caller_instance: impl Into<String>,
455        runtime: Rc<RefCell<Weak<NativeAppRuntime>>>,
456        requirements: Vec<lenso_app_plan::CapabilityRequirementPlan>,
457    ) -> Self {
458        Self {
459            requirements,
460            bindings: Vec::new(),
461            caller_instance: Rc::from(caller_instance.into()),
462            runtime,
463        }
464    }
465
466    /// Returns dependencies in the order materialized by the Resolved App Plan.
467    pub fn requirements(&self) -> &[lenso_app_plan::CapabilityRequirementPlan] {
468        &self.requirements
469    }
470
471    /// Narrows this view to one declared dependency, retaining optional absence.
472    pub fn requirement(&self, id: &str) -> Result<Self, RuntimeFailure> {
473        let requirement = self
474            .requirements
475            .iter()
476            .find(|requirement| requirement.requirement_id() == id)
477            .ok_or_else(|| RuntimeFailure::InvalidResolvedPlan {
478                detail: format!(
479                    "consumer `{}` has no requirement `{id}`",
480                    self.caller_instance
481                ),
482            })?;
483        Ok(Self {
484            requirements: vec![requirement.clone()],
485            bindings: self
486                .bindings
487                .iter()
488                .filter(|binding| binding.requirement_id() == id)
489                .cloned()
490                .collect(),
491            caller_instance: self.caller_instance.clone(),
492            runtime: self.runtime.clone(),
493        })
494    }
495
496    fn validate_lookup(
497        &self,
498        capability: &'static str,
499        version: &str,
500    ) -> Result<(), RuntimeFailure> {
501        let declarations = self
502            .requirements
503            .iter()
504            .filter(|requirement| requirement.capability_id() == capability)
505            .collect::<Vec<_>>();
506        match declarations.as_slice() {
507            [] => Err(RuntimeFailure::Unavailable { capability }),
508            [declaration] if declaration.descriptor_version() == version => Ok(()),
509            [_] => Err(RuntimeFailure::ProtocolViolation { capability }),
510            declarations => Err(RuntimeFailure::AmbiguousBinding {
511                capability,
512                providers: declarations.len(),
513            }),
514        }
515    }
516
517    /// Returns dependencies in the order materialized by the Resolved App Plan.
518    pub fn bindings(&self) -> &[PluginDependency] {
519        &self.bindings
520    }
521
522    /// Returns the number of explicit dependencies.
523    pub fn len(&self) -> usize {
524        self.bindings.len()
525    }
526
527    /// Returns whether this Plugin has no explicit dependencies.
528    pub fn is_empty(&self) -> bool {
529        self.bindings.is_empty()
530    }
531
532    /// Creates a Kernel Invocation Context for work initiated by this Plugin.
533    ///
534    /// The request identity and monotonic deadline come from the same Runtime
535    /// Driver as the App. The context is still owned by the caller and its
536    /// cancellation token remains explicit.
537    pub fn invocation_context(
538        &self,
539        deadline: Option<Duration>,
540        cancellation: CancellationToken,
541    ) -> Result<InvocationContext, RuntimeFailure> {
542        let runtime = self
543            .runtime
544            .borrow()
545            .upgrade()
546            .ok_or(RuntimeFailure::AdmissionClosed)?;
547        let request_id = runtime.request_ids.get();
548        runtime.request_ids.set(request_id.saturating_add(1));
549        Ok(InvocationContext::new(request_id, deadline, cancellation)
550            .with_shared_caller_instance(self.caller_instance.clone()))
551    }
552
553    /// Creates a Plugin Invocation Context with a Driver-relative deadline.
554    pub fn invocation_context_after(
555        &self,
556        timeout: Duration,
557        cancellation: CancellationToken,
558    ) -> Result<InvocationContext, RuntimeFailure> {
559        let runtime = self
560            .runtime
561            .borrow()
562            .upgrade()
563            .ok_or(RuntimeFailure::AdmissionClosed)?;
564        let deadline = (runtime.driver.now)().saturating_add(timeout);
565        drop(runtime);
566        self.invocation_context(Some(deadline), cancellation)
567    }
568
569    /// Returns the one explicitly bound typed dependency.
570    pub fn one<C: RequestCapability>(&self) -> Result<NativeRequestHandle<C>, RuntimeFailure> {
571        self.validate_lookup(C::ID, C::DESCRIPTOR_VERSION)?;
572        let handles: Vec<_> = self
573            .bindings
574            .iter()
575            .filter(|binding| binding.capability_id() == C::ID)
576            .filter_map(PluginDependency::handle)
577            .collect();
578        match handles.as_slice() {
579            [handle] => handle.typed::<C>(),
580            [] => Err(RuntimeFailure::Unavailable { capability: C::ID }),
581            handles => Err(RuntimeFailure::AmbiguousBinding {
582                capability: C::ID,
583                providers: handles.len(),
584            }),
585        }
586    }
587
588    /// Returns an optional explicitly bound typed dependency.
589    pub fn optional<C: RequestCapability>(
590        &self,
591    ) -> Result<Option<NativeRequestHandle<C>>, RuntimeFailure> {
592        self.validate_lookup(C::ID, C::DESCRIPTOR_VERSION)?;
593        match self
594            .bindings
595            .iter()
596            .filter(|binding| binding.capability_id() == C::ID)
597            .filter_map(PluginDependency::handle)
598            .collect::<Vec<_>>()
599            .as_slice()
600        {
601            [] => Ok(None),
602            [handle] => handle.typed::<C>().map(Some),
603            handles => Err(RuntimeFailure::AmbiguousBinding {
604                capability: C::ID,
605                providers: handles.len(),
606            }),
607        }
608    }
609
610    /// Returns all explicitly bound typed dependencies in resolved provider order.
611    pub fn many<C: RequestCapability>(
612        &self,
613    ) -> Result<Vec<NativeRequestHandle<C>>, RuntimeFailure> {
614        self.validate_lookup(C::ID, C::DESCRIPTOR_VERSION)?;
615        self.bindings
616            .iter()
617            .filter(|binding| binding.capability_id() == C::ID)
618            .filter_map(PluginDependency::handle)
619            .map(|handle| handle.typed::<C>())
620            .collect()
621    }
622
623    /// Returns the one explicitly bound typed stream dependency.
624    pub fn one_stream<C: StreamCapability>(&self) -> Result<NativeStreamHandle<C>, RuntimeFailure> {
625        self.validate_lookup(C::ID, C::DESCRIPTOR_VERSION)?;
626        let handles: Vec<_> = self
627            .bindings
628            .iter()
629            .filter(|binding| binding.capability_id() == C::ID)
630            .filter_map(PluginDependency::stream_handle)
631            .collect();
632        match handles.as_slice() {
633            [handle] => handle.typed::<C>(),
634            [] => Err(RuntimeFailure::Unavailable { capability: C::ID }),
635            handles => Err(RuntimeFailure::AmbiguousBinding {
636                capability: C::ID,
637                providers: handles.len(),
638            }),
639        }
640    }
641
642    /// Returns an optional explicitly bound typed stream dependency.
643    pub fn optional_stream<C: StreamCapability>(
644        &self,
645    ) -> Result<Option<NativeStreamHandle<C>>, RuntimeFailure> {
646        self.validate_lookup(C::ID, C::DESCRIPTOR_VERSION)?;
647        match self
648            .bindings
649            .iter()
650            .filter(|binding| binding.capability_id() == C::ID)
651            .filter_map(PluginDependency::stream_handle)
652            .collect::<Vec<_>>()
653            .as_slice()
654        {
655            [] => Ok(None),
656            [handle] => handle.typed::<C>().map(Some),
657            handles => Err(RuntimeFailure::AmbiguousBinding {
658                capability: C::ID,
659                providers: handles.len(),
660            }),
661        }
662    }
663
664    /// Returns all explicitly bound typed stream dependencies in Plan order.
665    pub fn many_stream<C: StreamCapability>(
666        &self,
667    ) -> Result<Vec<NativeStreamHandle<C>>, RuntimeFailure> {
668        self.validate_lookup(C::ID, C::DESCRIPTOR_VERSION)?;
669        self.bindings
670            .iter()
671            .filter(|binding| binding.capability_id() == C::ID)
672            .filter_map(PluginDependency::stream_handle)
673            .map(|handle| handle.typed::<C>())
674            .collect()
675    }
676
677    /// Returns one typed Event handle over every explicit binding in Plan order.
678    pub fn many_event<C: EventCapability>(&self) -> Result<NativeEventHandle<C>, RuntimeFailure> {
679        self.validate_lookup(C::ID, C::DESCRIPTOR_VERSION)?;
680        let handles: Vec<_> = self
681            .bindings
682            .iter()
683            .filter(|binding| binding.capability_id() == C::ID)
684            .filter_map(PluginDependency::event_handle)
685            .collect();
686        if handles.iter().any(|handle| {
687            handle.capability_id() != C::ID || handle.descriptor_version() != C::DESCRIPTOR_VERSION
688        }) {
689            return Err(RuntimeFailure::ProtocolViolation { capability: C::ID });
690        }
691        let runtime = self
692            .runtime
693            .borrow()
694            .upgrade()
695            .ok_or(RuntimeFailure::AdmissionClosed)?;
696        let endpoints = handles
697            .iter()
698            .map(|handle| handle.binding.clone())
699            .collect::<Vec<_>>();
700        Ok(NativeEventHandle::from_endpoints(
701            &endpoints,
702            runtime,
703            &self.caller_instance,
704            true,
705        ))
706    }
707
708    /// Returns the one explicitly bound typed Event dependency.
709    pub fn one_event<C: EventCapability>(&self) -> Result<NativeEventHandle<C>, RuntimeFailure> {
710        self.validate_lookup(C::ID, C::DESCRIPTOR_VERSION)?;
711        match self
712            .bindings
713            .iter()
714            .filter(|binding| binding.capability_id() == C::ID)
715            .filter_map(PluginDependency::event_handle)
716            .collect::<Vec<_>>()
717            .as_slice()
718        {
719            [handle] => handle.typed::<C>(),
720            [] => Err(RuntimeFailure::Unavailable { capability: C::ID }),
721            handles => Err(RuntimeFailure::AmbiguousBinding {
722                capability: C::ID,
723                providers: handles.len(),
724            }),
725        }
726    }
727
728    /// Returns an optional explicitly bound typed Event dependency.
729    pub fn optional_event<C: EventCapability>(
730        &self,
731    ) -> Result<Option<NativeEventHandle<C>>, RuntimeFailure> {
732        self.validate_lookup(C::ID, C::DESCRIPTOR_VERSION)?;
733        match self
734            .bindings
735            .iter()
736            .filter(|binding| binding.capability_id() == C::ID)
737            .filter_map(PluginDependency::event_handle)
738            .collect::<Vec<_>>()
739            .as_slice()
740        {
741            [] => Ok(None),
742            [handle] => handle.typed::<C>().map(Some),
743            handles => Err(RuntimeFailure::AmbiguousBinding {
744                capability: C::ID,
745                providers: handles.len(),
746            }),
747        }
748    }
749}