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1 : /*
2 : *
3 : * Copyright (c) 2020 Project CHIP Authors
4 : * All rights reserved.
5 : *
6 : * Licensed under the Apache License, Version 2.0 (the "License");
7 : * you may not use this file except in compliance with the License.
8 : * You may obtain a copy of the License at
9 : *
10 : * http://www.apache.org/licenses/LICENSE-2.0
11 : *
12 : * Unless required by applicable law or agreed to in writing, software
13 : * distributed under the License is distributed on an "AS IS" BASIS,
14 : * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 : * See the License for the specific language governing permissions and
16 : * limitations under the License.
17 : */
18 : #pragma once
19 :
20 : #include <app/CommandHandlerExchangeInterface.h>
21 : #include <app/ConcreteCommandPath.h>
22 : #include <app/data-model/EncodableToTLV.h>
23 : #include <app/data-model/Encode.h>
24 : #include <lib/core/CHIPCore.h>
25 : #include <lib/support/CodeUtils.h>
26 : #include <lib/support/IntrusiveList.h>
27 : #include <lib/support/logging/CHIPLogging.h>
28 : #include <protocols/interaction_model/StatusCode.h>
29 :
30 : namespace chip {
31 : namespace app {
32 :
33 : /**
34 : * A handler for incoming Invoke interactions.
35 : *
36 : * Allows adding responses to be sent in an InvokeResponse: see the various
37 : * "Add*" methods.
38 : *
39 : * Allows adding the responses asynchronously when using `CommandHandler::Handle`
40 : * (see documentation for `CommandHandler::Handle` for details)
41 : *
42 : * Upgrading notes: this class has moved to an interface from a previous more complex
43 : * implementation. If upgrading code between versions, please see docs/upgrading.md
44 : */
45 : class CommandHandler
46 : {
47 : public:
48 57 : virtual ~CommandHandler() = default;
49 :
50 : /**
51 : * Class that allows asynchronous command processing before sending a
52 : * response. When such processing is desired:
53 : *
54 : * 1) Create a Handle initialized with the CommandHandler that delivered the
55 : * incoming command.
56 : * 2) Ensure the Handle, or some Handle it's moved into via the move
57 : * constructor or move assignment operator, remains alive during the
58 : * course of the asynchronous processing.
59 : * 3) Ensure that the ConcreteCommandPath involved will be known when
60 : * sending the response.
61 : * 4) When ready to send the response:
62 : * * Ensure that no other Matter tasks are running in parallel (e.g. by
63 : * running on the Matter event loop or holding the Matter stack lock).
64 : * * Call Get() to get the CommandHandler.
65 : * * Check that Get() did not return null.
66 : * * Add the response to the CommandHandler via one of the Add* methods.
67 : * * Let the Handle get destroyed, or manually call Handle::Release() if
68 : * destruction of the Handle is not desirable for some reason.
69 : *
70 : * The Invoke Response will not be sent until all outstanding Handles have
71 : * been destroyed or have had Release called.
72 : */
73 : class Handle : public IntrusiveListNodeBase<>
74 : {
75 : public:
76 : Handle() {}
77 : Handle(const Handle & handle) = delete;
78 : Handle(Handle && handle)
79 : {
80 : Init(handle.mpHandler);
81 : handle.Release();
82 : }
83 : Handle(decltype(nullptr)) {}
84 : Handle(CommandHandler * handler);
85 36 : ~Handle() { Release(); }
86 :
87 : Handle & operator=(Handle && handle)
88 : {
89 : Release();
90 : Init(handle.mpHandler);
91 :
92 : handle.Release();
93 : return *this;
94 : }
95 :
96 : Handle & operator=(decltype(nullptr))
97 : {
98 : Release();
99 : return *this;
100 : }
101 :
102 : /**
103 : * Get the CommandHandler object it holds. Get() may return a nullptr if the CommandHandler object it holds is no longer
104 : * valid.
105 : */
106 : CommandHandler * Get();
107 :
108 : void Release();
109 :
110 87 : void Invalidate() { mpHandler = nullptr; }
111 :
112 : private:
113 : void Init(CommandHandler * handler);
114 :
115 : CommandHandler * mpHandler = nullptr;
116 : };
117 :
118 : /**
119 : * Adds the given command status and returns any failures in adding statuses (e.g. out
120 : * of buffer space) to the caller. `context` is an optional (if not nullptr)
121 : * debug string to include in logging.
122 : */
123 : virtual CHIP_ERROR FallibleAddStatus(const ConcreteCommandPath & aRequestCommandPath,
124 : const Protocols::InteractionModel::ClusterStatusCode & aStatus,
125 : const char * context = nullptr) = 0;
126 14 : CHIP_ERROR FallibleAddStatus(const ConcreteCommandPath & aRequestCommandPath, const Protocols::InteractionModel::Status aStatus,
127 : const char * context = nullptr)
128 : {
129 14 : return FallibleAddStatus(aRequestCommandPath, Protocols::InteractionModel::ClusterStatusCode{ aStatus }, context);
130 : }
131 :
132 : /**
133 : * Adds an IM global or Cluster status when the caller is unable to handle any failures. Logging is performed
134 : * and failure to register the status is checked with VerifyOrDie. `context` is an optional (if not nullptr)
135 : * debug string to include in logging.
136 : */
137 : virtual void AddStatus(const ConcreteCommandPath & aRequestCommandPath,
138 : const Protocols::InteractionModel::ClusterStatusCode & aStatus, const char * context = nullptr) = 0;
139 0 : void AddStatus(const ConcreteCommandPath & aRequestCommandPath, const Protocols::InteractionModel::Status aStatus,
140 : const char * context = nullptr)
141 : {
142 0 : AddStatus(aRequestCommandPath, Protocols::InteractionModel::ClusterStatusCode{ aStatus }, context);
143 0 : }
144 :
145 : /**
146 : * Sets the response to indicate Success with a cluster-specific status code `aClusterStatus` included.
147 : *
148 : * NOTE: For regular success, what you want is AddStatus/FailibleAddStatus(aRequestCommandPath,
149 : * InteractionModel::Status::Success).
150 : */
151 0 : virtual CHIP_ERROR AddClusterSpecificSuccess(const ConcreteCommandPath & aRequestCommandPath, ClusterStatus aClusterStatus)
152 : {
153 0 : return FallibleAddStatus(aRequestCommandPath,
154 0 : Protocols::InteractionModel::ClusterStatusCode::ClusterSpecificSuccess(aClusterStatus));
155 : }
156 :
157 : /**
158 : * Sets the response to indicate Failure with a cluster-specific status code `aClusterStatus` included.
159 : */
160 0 : virtual CHIP_ERROR AddClusterSpecificFailure(const ConcreteCommandPath & aRequestCommandPath, ClusterStatus aClusterStatus)
161 : {
162 0 : return FallibleAddStatus(aRequestCommandPath,
163 0 : Protocols::InteractionModel::ClusterStatusCode::ClusterSpecificFailure(aClusterStatus));
164 : }
165 :
166 : /**
167 : * GetAccessingFabricIndex() may only be called during synchronous command
168 : * processing. Anything that runs async (while holding a
169 : * CommandHandler::Handle or equivalent) must not call this method, because
170 : * it will not work right if the session we're using was evicted.
171 : */
172 : virtual FabricIndex GetAccessingFabricIndex() const = 0;
173 :
174 : /**
175 : * API for adding a data response. The `aEncodable` is generally expected to encode
176 : * a ClusterName::Commands::CommandName::Type struct, however any object should work.
177 : *
178 : * @param [in] aRequestCommandPath the concrete path of the command we are
179 : * responding to.
180 : * @param [in] aResponseCommandId the command whose content is being encoded.
181 : * @param [in] aEncodable - an encodable that places the command data structure
182 : * for `aResponseCommandId` into a TLV Writer.
183 : *
184 : * If you have no great way of handling the returned CHIP_ERROR, consider
185 : * using `AddResponse` which will automatically reply with `Failure` in
186 : * case AddResponseData fails.
187 : */
188 : virtual CHIP_ERROR AddResponseData(const ConcreteCommandPath & aRequestCommandPath, CommandId aResponseCommandId,
189 : const DataModel::EncodableToTLV & aEncodable) = 0;
190 :
191 : /**
192 : * Attempts to encode a response to a command.
193 : *
194 : * `aRequestCommandPath` represents the request path (endpoint/cluster/commandid) and the reply
195 : * will preserve the same path and switch the command id to aResponseCommandId.
196 : *
197 : * As this command does not return any error codes, it must try its best to encode the reply
198 : * and if it fails, it MUST encode a `Protocols::InteractionModel::Status::Failure` as a
199 : * reply (i.e. a reply is guaranteed to be sent).
200 : *
201 : * Above is the main difference from AddResponseData: AddResponse will auto-reply with failure while
202 : * AddResponseData allows the caller to try to deal with any CHIP_ERRORs.
203 : */
204 : virtual void AddResponse(const ConcreteCommandPath & aRequestCommandPath, CommandId aResponseCommandId,
205 : const DataModel::EncodableToTLV & aEncodable) = 0;
206 :
207 : /**
208 : * Check whether the InvokeRequest we are handling is a timed invoke.
209 : */
210 : virtual bool IsTimedInvoke() const = 0;
211 :
212 : /**
213 : * @brief Flush acks right away for a slow command
214 : *
215 : * Some commands that do heavy lifting of storage/crypto should
216 : * ack right away to improve reliability and reduce needless retries. This
217 : * method can be manually called in commands that are especially slow to
218 : * immediately schedule an acknowledgement (if needed) since the delayed
219 : * stand-alone ack timer may actually not hit soon enough due to blocking command
220 : * execution.
221 : *
222 : */
223 : virtual void FlushAcksRightAwayOnSlowCommand() = 0;
224 :
225 : virtual Access::SubjectDescriptor GetSubjectDescriptor() const = 0;
226 :
227 : /**
228 : * Gets the inner exchange context object, without ownership.
229 : *
230 : * WARNING: This is dangerous, since it is directly interacting with the
231 : * exchange being managed automatically by mpResponder and
232 : * if not done carefully, may end up with use-after-free errors.
233 : *
234 : * @return The inner exchange context, might be nullptr if no
235 : * exchange context has been assigned or the context
236 : * has been released.
237 : */
238 : virtual Messaging::ExchangeContext * GetExchangeContext() const = 0;
239 :
240 : /**
241 : * API for adding a data response. The template parameter T is generally
242 : * expected to be a ClusterName::Commands::CommandName::Type struct, but any
243 : * object that can be encoded using the DataModel::Encode machinery and
244 : * exposes the right command id will work.
245 : *
246 : * If you have no great way of handling the returned CHIP_ERROR, consider
247 : * using `AddResponse` which will automatically reply with `Failure` in
248 : * case AddResponseData fails.
249 : *
250 : * @param [in] aRequestCommandPath the concrete path of the command we are
251 : * responding to.
252 : *
253 : * The response path will be the same as the request, except the
254 : * reply command ID used will be `CommandData::GetCommandId()` assumed
255 : * to be a member of the templated type
256 : *
257 : * @param [in] aData the data for the response. It is expected to provide
258 : * `GetCommandData` as a STATIC on its type as well as encode the
259 : * correct data structure for building a reply.
260 : */
261 : template <typename CommandData>
262 : CHIP_ERROR AddResponseData(const ConcreteCommandPath & aRequestCommandPath, const CommandData & aData)
263 : {
264 : DataModel::EncodableType<CommandData> encoder(aData);
265 : return AddResponseData(aRequestCommandPath, CommandData::GetCommandId(), encoder);
266 : }
267 :
268 : /**
269 : * API for adding a response. This will try to encode a data response (response command), and if that fails
270 : * it will encode a Protocols::InteractionModel::Status::Failure status response instead.
271 : *
272 : * Above is the main difference from AddResponseData: AddResponse will auto-reply with failure while
273 : * AddResponseData allows the caller to try to deal with any CHIP_ERRORs.
274 : *
275 : * The template parameter T is generally expected to be a ClusterName::Commands::CommandName::Type struct, but any object that
276 : * can be encoded using the DataModel::Encode machinery and exposes the right command id will work.
277 : *
278 : * Since the function will call AddStatus when it fails to encode the data, it cannot send any response when it fails to encode
279 : * a status code since another AddStatus call will also fail. The error from AddStatus will just be logged.
280 : *
281 : * @param [in] aRequestCommandPath the concrete path of the command we are
282 : * responding to.
283 : * @param [in] aData the data for the response.
284 : */
285 : template <typename CommandData>
286 : void AddResponse(const ConcreteCommandPath & aRequestCommandPath, const CommandData & aData)
287 : {
288 : DataModel::EncodableType<CommandData> encodable(aData);
289 : AddResponse(aRequestCommandPath, CommandData::GetCommandId(), encodable);
290 : }
291 :
292 : protected:
293 : /**
294 : * IncrementHoldOff will increase the inner refcount of the CommandHandler.
295 : *
296 : * Users should use CommandHandler::Handle for management the lifespan of the CommandHandler.
297 : * DefRef should be released in reasonable time, and Close() should only be called when the refcount reached 0.
298 : */
299 0 : virtual void IncrementHoldOff(Handle * apHandle) {}
300 :
301 : /**
302 : * DecrementHoldOff is used by CommandHandler::Handle for decreasing the refcount of the CommandHandler.
303 : * When refcount reached 0, CommandHandler will send the response to the peer and shutdown.
304 : */
305 0 : virtual void DecrementHoldOff(Handle * apHandle) {}
306 : };
307 :
308 : } // namespace app
309 : } // namespace chip
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