fdf_component/node/
offers.rs

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1// Copyright 2024 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5use std::marker::PhantomData;
6
7use fidl::endpoints::{ServiceMarker, ServiceRequest};
8use fidl_fuchsia_component_decl::{NameMapping, OfferService};
9use fidl_fuchsia_driver_framework::Offer;
10use fuchsia_component::server::{FidlServiceMember, ServiceFs, ServiceObjTrait};
11use fuchsia_component::DEFAULT_SERVICE_INSTANCE;
12
13/// A builder for creating [`Offer`]-compatible values for [`crate::NodeBuilder::add_offer`] that
14/// service a zircon fidl service.
15///
16/// The methods on this that start with `add_` are helpers that will both register a service handler
17/// with a [`ServiceFs`] and register the instance name in the structure. If you're handling adding
18/// your service handlers to the outgoing directory yourself, you can just use the non-`add_`
19/// methods to register them.
20///
21/// If no calls to add any instances are made, then when this is transformed into a service offer
22/// it will be as if a single default instance with the default name was added.
23pub struct ZirconServiceOffer<S> {
24    service_name: String,
25    instances: Vec<NameMapping>,
26    _p: PhantomData<S>,
27}
28
29impl<S> ZirconServiceOffer<S> {
30    /// Builds an offer for a zircon transport service based on the [`ServiceMarker`] for `S`.
31    ///
32    /// If the compiler can't deduce the type of `S` (which may be the case if you're not using the
33    /// `add_` methods to add to a [`ServiceFs`] at the same time), you can use [`Self::new_marker`]
34    /// to make it explicit.
35    pub fn new() -> Self
36    where
37        S: ServiceMarker,
38    {
39        let service_name = S::SERVICE_NAME.to_owned();
40        let instances = vec![];
41        Self { service_name, instances, _p: PhantomData }
42    }
43
44    /// Builds an offer for a zircon transport service based on the given [`ServiceMarker`].
45    ///
46    /// This is mostly useful if the compiler can't derive the type of `S` on its own.
47    pub fn new_marker(_marker: S) -> Self
48    where
49        S: ServiceMarker,
50    {
51        let service_name = S::SERVICE_NAME.to_owned();
52        let instances = vec![];
53        Self { service_name, instances, _p: PhantomData }
54    }
55
56    /// Adds the given service instance to this offer and to the [`ServiceFs`] passed in, using the
57    /// generator function `f`. The type of the service will be derived from the result of the
58    /// generator function and it will be added with the name `name` which will be mapped to the
59    /// default instance name to child components ([`DEFAULT_SERVICE_INSTANCE`]).
60    pub fn add_default_named<O: ServiceObjTrait, F, SR>(
61        self,
62        fs: &mut ServiceFs<O>,
63        name: impl Into<String>,
64        f: F,
65    ) -> Self
66    where
67        F: Fn(SR) -> O::Output,
68        F: Clone,
69        SR: ServiceRequest<Service = S>,
70        FidlServiceMember<F, SR, O::Output>: Into<O>,
71    {
72        let name = name.into();
73        fs.dir("svc").add_fidl_service_instance(name.clone(), f);
74        self.named_default_instance(name)
75    }
76
77    /// Adds the given service instance to this offer and to the [`ServiceFs`] passed in, using the
78    /// generator function `f`. The type of the service will be derived from the result of the
79    /// generator function and it will be added with the name `name`.
80    pub fn add_named<O: ServiceObjTrait, F, SR>(
81        self,
82        fs: &mut ServiceFs<O>,
83        name: impl Into<String>,
84        f: F,
85    ) -> Self
86    where
87        F: Fn(SR) -> O::Output,
88        F: Clone,
89        SR: ServiceRequest<Service = S>,
90        FidlServiceMember<F, SR, O::Output>: Into<O>,
91    {
92        let name = name.into();
93        fs.dir("svc").add_fidl_service_instance(name.clone(), f);
94        self.named_instance(name)
95    }
96
97    /// Adds the named instance as the `default` instance of this service offer (as specified
98    /// by [`DEFAULT_SERVICE_INSTANCE`]). If you are only offering a single instance that is
99    /// already called `default`, you do not need to call this.
100    pub fn named_default_instance(mut self, name: impl Into<String>) -> Self {
101        self.instances.push(NameMapping {
102            source_name: name.into(),
103            target_name: DEFAULT_SERVICE_INSTANCE.to_owned(),
104        });
105        self
106    }
107
108    /// Adds the named instance to the offer without mapping it to the default instance name.
109    /// You can use this to add additional instances offered in your outgoing directory.
110    pub fn named_instance(mut self, name: impl Into<String>) -> Self {
111        let source_name = name.into();
112        let target_name = source_name.clone();
113        self.instances.push(NameMapping { source_name, target_name });
114        self
115    }
116
117    /// Finalize the construction of the [`Offer`] object for use with
118    /// [`super::NodeBuilder::add_offer`].
119    pub fn build(self) -> Offer {
120        // if no instances were added, assume there's a single default instance
121        let mut instances = self.instances;
122        if instances.is_empty() {
123            instances.push(NameMapping {
124                source_name: DEFAULT_SERVICE_INSTANCE.to_owned(),
125                target_name: DEFAULT_SERVICE_INSTANCE.to_owned(),
126            });
127        }
128        let service = OfferService {
129            source_name: Some(self.service_name.clone()),
130            target_name: Some(self.service_name),
131            renamed_instances: Some(instances),
132            ..Default::default()
133        };
134        Offer::ZirconTransport(fidl_fuchsia_component_decl::Offer::Service(service))
135    }
136}
fdf_component/node/offers.rs

fdf_component/node/
offers.rs
