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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 <access/SubjectDescriptor.h>
21 : #include <app/ConcreteCommandPath.h>
22 : #include <app/data-model/EncodableToTLV.h>
23 : #include <app/data-model/Encode.h>
24 : #include <app/data-model/FabricScoped.h>
25 : #include <lib/core/CHIPCore.h>
26 : #include <lib/support/CodeUtils.h>
27 : #include <lib/support/IntrusiveList.h>
28 : #include <lib/support/logging/CHIPLogging.h>
29 : #include <messaging/ExchangeContext.h>
30 : #include <protocols/interaction_model/StatusCode.h>
31 :
32 : namespace chip {
33 : namespace app {
34 :
35 : /**
36 : * A handler for incoming Invoke interactions. This handles incoming Invoke
37 : * Request messages and generates Invoke Response messages.
38 : *
39 : * Allows adding responses (status, or server to client command) to be sent in
40 : * the Invoke Response message: see the various "Add*" methods.
41 : *
42 : * Allows adding the responses asynchronously when using `CommandHandler::Handle`
43 : * (see documentation for `CommandHandler::Handle` for details)
44 : *
45 : * Upgrading notes: this class has moved to an interface from a previous more complex
46 : * implementation. If upgrading code between versions, please see docs/upgrading.md
47 : */
48 : class CommandHandler
49 : {
50 : public:
51 57 : virtual ~CommandHandler() = default;
52 :
53 : /**
54 : * Class that allows asynchronous command processing before sending a
55 : * response. When such processing is desired:
56 : *
57 : * 1) Create a Handle initialized with the CommandHandler that delivered the
58 : * incoming command.
59 : * 2) Ensure the Handle, or some Handle it's moved into via the move
60 : * constructor or move assignment operator, remains alive during the
61 : * course of the asynchronous processing.
62 : * 3) Ensure that the ConcreteCommandPath involved will be known when
63 : * sending the response.
64 : * 4) When ready to send the response:
65 : * * Ensure that no other Matter tasks are running in parallel (e.g. by
66 : * running on the Matter event loop or holding the Matter stack lock).
67 : * * Call Get() to get the CommandHandler.
68 : * * Check that Get() did not return null.
69 : * * Add the response to the CommandHandler via one of the Add* methods.
70 : * * Let the Handle get destroyed, or manually call Handle::Release() if
71 : * destruction of the Handle is not desirable for some reason.
72 : *
73 : * The Invoke Response will not be sent until all outstanding Handles have
74 : * been destroyed or have had Release called.
75 : */
76 : class Handle : public IntrusiveListNodeBase<>
77 : {
78 : public:
79 : Handle() {}
80 : Handle(const Handle & handle) = delete;
81 : Handle(Handle && handle)
82 : {
83 : Init(handle.mpHandler);
84 : handle.Release();
85 : }
86 : Handle(decltype(nullptr)) {}
87 : Handle(CommandHandler * handler);
88 36 : ~Handle() { Release(); }
89 :
90 : Handle & operator=(Handle && handle)
91 : {
92 : Release();
93 : Init(handle.mpHandler);
94 :
95 : handle.Release();
96 : return *this;
97 : }
98 :
99 : Handle & operator=(decltype(nullptr))
100 : {
101 : Release();
102 : return *this;
103 : }
104 :
105 : /**
106 : * Get the CommandHandler object it holds. Get() may return a nullptr if the CommandHandler object it holds is no longer
107 : * valid.
108 : */
109 : CommandHandler * Get();
110 :
111 : void Release();
112 :
113 87 : void Invalidate() { mpHandler = nullptr; }
114 :
115 : private:
116 : void Init(CommandHandler * handler);
117 :
118 : CommandHandler * mpHandler = nullptr;
119 : };
120 :
121 : /**
122 : * Adds the given command status and returns any failures in adding statuses (e.g. out
123 : * of buffer space) to the caller. `context` is an optional (if not nullptr)
124 : * debug string to include in logging.
125 : */
126 : virtual CHIP_ERROR FallibleAddStatus(const ConcreteCommandPath & aRequestCommandPath,
127 : const Protocols::InteractionModel::ClusterStatusCode & aStatus,
128 : const char * context = nullptr) = 0;
129 14 : CHIP_ERROR FallibleAddStatus(const ConcreteCommandPath & aRequestCommandPath, const Protocols::InteractionModel::Status aStatus,
130 : const char * context = nullptr)
131 : {
132 14 : return FallibleAddStatus(aRequestCommandPath, Protocols::InteractionModel::ClusterStatusCode{ aStatus }, context);
133 : }
134 :
135 : /**
136 : * Adds an IM global or Cluster status when the caller is unable to handle any failures. Logging is performed
137 : * and failure to register the status is checked with VerifyOrDie. `context` is an optional (if not nullptr)
138 : * debug string to include in logging.
139 : */
140 : virtual void AddStatus(const ConcreteCommandPath & aRequestCommandPath,
141 : const Protocols::InteractionModel::ClusterStatusCode & aStatus, const char * context = nullptr) = 0;
142 0 : void AddStatus(const ConcreteCommandPath & aRequestCommandPath, const Protocols::InteractionModel::Status aStatus,
143 : const char * context = nullptr)
144 : {
145 0 : AddStatus(aRequestCommandPath, Protocols::InteractionModel::ClusterStatusCode{ aStatus }, context);
146 0 : }
147 :
148 : /**
149 : * Sets the response to indicate Success with a cluster-specific status code `aClusterStatus` included.
150 : *
151 : * NOTE: For regular success, what you want is AddStatus/FailibleAddStatus(aRequestCommandPath,
152 : * InteractionModel::Status::Success).
153 : */
154 0 : virtual CHIP_ERROR AddClusterSpecificSuccess(const ConcreteCommandPath & aRequestCommandPath, ClusterStatus aClusterStatus)
155 : {
156 0 : return FallibleAddStatus(aRequestCommandPath,
157 0 : Protocols::InteractionModel::ClusterStatusCode::ClusterSpecificSuccess(aClusterStatus));
158 : }
159 :
160 : /**
161 : * Sets the response to indicate Failure with a cluster-specific status code `aClusterStatus` included.
162 : */
163 0 : virtual CHIP_ERROR AddClusterSpecificFailure(const ConcreteCommandPath & aRequestCommandPath, ClusterStatus aClusterStatus)
164 : {
165 0 : return FallibleAddStatus(aRequestCommandPath,
166 0 : Protocols::InteractionModel::ClusterStatusCode::ClusterSpecificFailure(aClusterStatus));
167 : }
168 :
169 : /**
170 : * GetAccessingFabricIndex() may only be called during synchronous command
171 : * processing. Anything that runs async (while holding a
172 : * CommandHandler::Handle or equivalent) must not call this method, because
173 : * it will not work right if the session we're using was evicted.
174 : */
175 : virtual FabricIndex GetAccessingFabricIndex() const = 0;
176 :
177 : /**
178 : * API for adding a data response. The `aEncodable` is generally expected to encode
179 : * a ClusterName::Commands::CommandName::Type struct, however any object should work.
180 : *
181 : * @param [in] aRequestCommandPath the concrete path of the command we are
182 : * responding to.
183 : * @param [in] aResponseCommandId the command whose content is being encoded.
184 : * @param [in] aEncodable - an encodable that places the command data structure
185 : * for `aResponseCommandId` into a TLV Writer.
186 : *
187 : * If you have no great way of handling the returned CHIP_ERROR, consider
188 : * using `AddResponse` which will automatically reply with `Failure` in
189 : * case AddResponseData fails.
190 : */
191 : virtual CHIP_ERROR AddResponseData(const ConcreteCommandPath & aRequestCommandPath, CommandId aResponseCommandId,
192 : const DataModel::EncodableToTLV & aEncodable) = 0;
193 :
194 : /**
195 : * Attempts to encode a response to a command.
196 : *
197 : * `aRequestCommandPath` represents the request path (endpoint/cluster/commandid) and the reply
198 : * will preserve the same path and switch the command id to aResponseCommandId.
199 : *
200 : * As this command does not return any error codes, it must try its best to encode the reply
201 : * and if it fails, it MUST encode a `Protocols::InteractionModel::Status::Failure` as a
202 : * reply (i.e. a reply is guaranteed to be sent).
203 : *
204 : * Above is the main difference from AddResponseData: AddResponse will auto-reply with failure while
205 : * AddResponseData allows the caller to try to deal with any CHIP_ERRORs.
206 : */
207 : virtual void AddResponse(const ConcreteCommandPath & aRequestCommandPath, CommandId aResponseCommandId,
208 : const DataModel::EncodableToTLV & aEncodable) = 0;
209 :
210 : /**
211 : * Check whether the InvokeRequest we are handling is a timed invoke.
212 : */
213 : virtual bool IsTimedInvoke() const = 0;
214 :
215 : /**
216 : * @brief Flush acks right away for a slow command
217 : *
218 : * Some commands that do heavy lifting of storage/crypto should
219 : * ack right away to improve reliability and reduce needless retries. This
220 : * method can be manually called in commands that are especially slow to
221 : * immediately schedule an acknowledgement (if needed) since the delayed
222 : * stand-alone ack timer may actually not hit soon enough due to blocking command
223 : * execution.
224 : *
225 : */
226 : virtual void FlushAcksRightAwayOnSlowCommand() = 0;
227 :
228 : virtual Access::SubjectDescriptor GetSubjectDescriptor() const = 0;
229 :
230 : /**
231 : * Gets the inner exchange context object, without ownership.
232 : *
233 : * WARNING: This is dangerous, since it is directly interacting with the
234 : * exchange being managed automatically by mpResponder and
235 : * if not done carefully, may end up with use-after-free errors.
236 : *
237 : * @return The inner exchange context, might be nullptr if no
238 : * exchange context has been assigned or the context
239 : * has been released.
240 : */
241 : virtual Messaging::ExchangeContext * GetExchangeContext() const = 0;
242 :
243 : /**
244 : * API for adding a data response. The template parameter T is generally
245 : * expected to be a ClusterName::Commands::CommandName::Type struct, but any
246 : * object that can be encoded using the DataModel::Encode machinery and
247 : * exposes the right command id will work.
248 : *
249 : * If you have no great way of handling the returned CHIP_ERROR, consider
250 : * using `AddResponse` which will automatically reply with `Failure` in
251 : * case AddResponseData fails.
252 : *
253 : * @param [in] aRequestCommandPath the concrete path of the command we are
254 : * responding to.
255 : *
256 : * The response path will be the same as the request, except the
257 : * reply command ID used will be `CommandData::GetCommandId()` assumed
258 : * to be a member of the templated type
259 : *
260 : * @param [in] aData the data for the response. It is expected to provide
261 : * `GetCommandData` as a STATIC on its type as well as encode the
262 : * correct data structure for building a reply.
263 : */
264 : template <typename CommandData>
265 : CHIP_ERROR AddResponseData(const ConcreteCommandPath & aRequestCommandPath, const CommandData & aData)
266 : {
267 : EncodableResponseCommandPayload<CommandData> encoder(aData);
268 : return AddResponseData(aRequestCommandPath, CommandData::GetCommandId(), encoder);
269 : }
270 :
271 : /**
272 : * API for adding a response. This will try to encode a data response (response command), and if that fails
273 : * it will encode a Protocols::InteractionModel::Status::Failure status response instead.
274 : *
275 : * Above is the main difference from AddResponseData: AddResponse will auto-reply with failure while
276 : * AddResponseData allows the caller to try to deal with any CHIP_ERRORs.
277 : *
278 : * The template parameter T is generally expected to be a ClusterName::Commands::CommandName::Type struct, but any object that
279 : * can be encoded using the DataModel::Encode machinery and exposes the right command id will work.
280 : *
281 : * Since the function will call AddStatus when it fails to encode the data, it cannot send any response when it fails to encode
282 : * a status code since another AddStatus call will also fail. The error from AddStatus will just be logged.
283 : *
284 : * @param [in] aRequestCommandPath the concrete path of the command we are
285 : * responding to.
286 : * @param [in] aData the data for the response.
287 : */
288 : template <typename CommandData>
289 : void AddResponse(const ConcreteCommandPath & aRequestCommandPath, const CommandData & aData)
290 : {
291 : EncodableResponseCommandPayload<CommandData> encodable(aData);
292 : AddResponse(aRequestCommandPath, CommandData::GetCommandId(), encodable);
293 : }
294 :
295 : protected:
296 : // Encoding a response command payload requires a fabric index, in general,
297 : // because any fabric-scoped fields in the payload need it to deal with
298 : // their fabric-sensitive fields.
299 : template <typename CommandData>
300 : class EncodableResponseCommandPayload : public DataModel::EncodableToTLV
301 : {
302 : public:
303 : EncodableResponseCommandPayload(const CommandData & value) : mValue(value) {}
304 :
305 : CHIP_ERROR EncodeTo(DataModel::FabricAwareTLVWriter & writer, TLV::Tag tag) const final
306 : {
307 : return DataModel::EncodeResponseCommandPayload(writer, tag, mValue);
308 : }
309 :
310 : CHIP_ERROR EncodeTo(TLV::TLVWriter & writer, TLV::Tag tag) const final
311 : {
312 : // Not used, keep it as small as we can.
313 : return CHIP_ERROR_INCORRECT_STATE;
314 : }
315 :
316 : private:
317 : const CommandData & mValue;
318 : };
319 :
320 : /**
321 : * IncrementHoldOff will increase the inner refcount of the CommandHandler.
322 : *
323 : * Users should use CommandHandler::Handle for management the lifespan of the CommandHandler.
324 : * DefRef should be released in reasonable time, and Close() should only be called when the refcount reached 0.
325 : */
326 0 : virtual void IncrementHoldOff(Handle * apHandle) {}
327 :
328 : /**
329 : * DecrementHoldOff is used by CommandHandler::Handle for decreasing the refcount of the CommandHandler.
330 : * When refcount reached 0, CommandHandler will send the response to the peer and shutdown.
331 : */
332 0 : virtual void DecrementHoldOff(Handle * apHandle) {}
333 : };
334 :
335 : } // namespace app
336 : } // namespace chip
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