1 /*
2 * Copyright (C) 2022 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #ifndef CHRE_UTIL_PIGWEED_RPC_CLIENT_H_
18 #define CHRE_UTIL_PIGWEED_RPC_CLIENT_H_
19
20 #include <cstdint>
21
22 #include "chre/util/non_copyable.h"
23 #include "chre/util/optional.h"
24 #include "chre/util/pigweed/chre_channel_output.h"
25 #include "chre/util/unique_ptr.h"
26 #include "chre_api/chre.h"
27 #include "pw_rpc/client.h"
28 #include "pw_span/span.h"
29 #include "rpc_helper.h"
30
31 namespace chre {
32
33 /**
34 * RPC Client wrapping a Pigweed RPC client.
35 *
36 * This helper class handles Pigweed RPC calls on the client side.
37 *
38 * The `handleEvent` method must be called at the beginning of the
39 * `nanoappHandleEvent` function to handle RPC responses from the server.
40 */
41 class RpcClient : public NonCopyable {
42 public:
43 /**
44 * @param serverNanoappId Nanoapp ID of the server.
45 */
RpcClient(uint64_t serverNanoappId)46 explicit RpcClient(uint64_t serverNanoappId)
47 : mServerNanoappId((serverNanoappId)) {}
48
~RpcClient()49 ~RpcClient() {
50 chreConfigureNanoappInfoEvents(false);
51 }
52
53 /**
54 * Handles events related to RPC services.
55 *
56 * Handles the following events:
57 * - PW_RPC_CHRE_NAPP_RESPONSE_EVENT_TYPE: handle the server responses,
58 * - CHRE_EVENT_NANOAPP_STOPPED: close the channel when the server nanoapp
59 * terminates.
60 *
61 * @param senderInstanceId The Instance ID for the source of this event.
62 * @param eventType The event type.
63 * @param eventData The associated data, if any, for this specific type of
64 * event.
65 * @return whether any event was handled successfully.
66 */
67 bool handleEvent(uint32_t senderInstanceId, uint16_t eventType,
68 const void *eventData);
69
70 /**
71 * Returns a service client.
72 *
73 * NOTE: The template parameter must be set to the Pigweed client type,
74 * i.e. pw::rpc::pw_rpc::nanopb::<ServiceName>::Client
75
76 * @return The service client. It has no value on errors.
77 */
78 template <typename T>
79 Optional<T> get();
80
81 /**
82 * Returns whether the server nanoapp supports the service.
83 *
84 * Also returns false when the nanoapp is not loaded.
85 *
86 * @return whether the service is published by the server.
87 */
88 bool hasService(uint64_t id, uint32_t version);
89
90 private:
91 /**
92 * Handles responses from the server.
93 *
94 * This method must be called when nanoapps receive a
95 * PW_RPC_CHRE_NAPP_RESPONSE_EVENT_TYPE event.
96 *
97 * @param senderInstanceId The Instance ID for the source of this event.
98 * @param eventData The associated data, if any.
99 * @return whether the RPC was handled successfully.
100 */
101 bool handleMessageFromServer(uint32_t senderInstanceId,
102 const void *eventData);
103
104 /**
105 * Closes the Pigweed channel when the server terminates.
106 *
107 * @param notification The eventData associated to a
108 * CHRE_EVENT_NANOAPP_STOPPED event.
109 */
110 void handleNanoappStopped(const void *eventData);
111
112 ChreClientNanoappChannelOutput mChannelOutput;
113 pw::rpc::Client mRpcClient;
114 uint64_t mServerNanoappId;
115 uint32_t mChannelId = 0;
116 };
117
118 template <typename T>
get()119 Optional<T> RpcClient::get() {
120 if (mChannelId == 0) {
121 struct chreNanoappInfo info;
122
123 if (!chreGetNanoappInfoByAppId(mServerNanoappId, &info) ||
124 info.instanceId > kRpcNanoappMaxId) {
125 return Optional<T>();
126 }
127
128 mChannelId = chreGetInstanceId();
129 mChannelOutput.setServer(info.instanceId);
130 mRpcClient.OpenChannel(mChannelId, mChannelOutput);
131 }
132
133 chreConfigureNanoappInfoEvents(true);
134 return T(mRpcClient, mChannelId);
135 }
136
137 } // namespace chre
138
139 #endif // CHRE_UTIL_PIGWEED_RPC_SERVER_H_