Line data    Source code

       1              : /*
       2              :  *    Copyright (c) 2025 Project CHIP Authors
       3              :  *    All rights reserved.
       4              :  *
       5              :  *    Licensed under the Apache License, Version 2.0 (the "License");
       6              :  *    you may not use this file except in compliance with the License.
       7              :  *    You may obtain a copy of the License at
       8              :  *
       9              :  *        http://www.apache.org/licenses/LICENSE-2.0
      10              :  *
      11              :  *    Unless required by applicable law or agreed to in writing, software
      12              :  *    distributed under the License is distributed on an "AS IS" BASIS,
      13              :  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      14              :  *    See the License for the specific language governing permissions and
      15              :  *    limitations under the License.
      16              :  */
      17              : #pragma once
      18              : 
      19              : #include <app/ConcreteClusterPath.h>
      20              : #include <app/server-cluster/ServerClusterContext.h>
      21              : #include <app/server-cluster/ServerClusterInterface.h>
      22              : #include <lib/core/DataModelTypes.h>
      23              : #include <lib/support/Span.h>
      24              : 
      25              : namespace chip::app {
      26              : 
      27              : /// A proxy for a ServerClusterInterface that adds data version management and attribute change notification
      28              : /// capability that works together with an underlying server cluster interface:
      29              : ///   - a ServerClusterContext received from startup is retained
      30              : ///   - a data version delta is maintained compared to underlying, to account for extra data
      31              : ///
      32              : /// This class wraps an existing ServerClusterInterface instance and is intended to be
      33              : /// used as a base class for extending cluster functionality, like adding new attributes
      34              : /// or commands to an existing server cluster interface.
      35              : ///
      36              : /// The class is intended to wrap a SINGLE cluster path for a given interface, even if the interface
      37              : /// itself supports multiple paths.
      38              : ///
      39              : /// Expected usage is that the `ServerClusterExtension` is registered while the `underlying` interface
      40              : /// is not. This can be used to wrap an existing registered interface like:
      41              : ///
      42              : /// ```
      43              : /// ServerClusterInterface *underlying = registry.Get(clusterPath);
      44              : /// registry.Unregister(underlying);
      45              : /// auto extension = std::make_unique<RegisteredServerCluster<Extension>>(clusterPath, *underlying);
      46              : /// registry.Register(extension->Registration());
      47              : /// ```
      48              : ///
      49              : /// An extension could be chained like `Extension2(path2, Extension1(path1, underlying))` if more than
      50              : /// one extension is desired.
      51              : ///
      52              : /// NOTES:
      53              : ///   - if changing an attribute (via WriteAttribute or as part of other operations), remember to call
      54              : ///     NotifyAttributeChanged so that attribute subscriptions work correctly.
      55              : class ServerClusterExtension : public ServerClusterInterface
      56              : {
      57              : public:
      58            4 :     explicit ServerClusterExtension(const ConcreteClusterPath & path, ServerClusterInterface & underlying) :
      59            4 :         mClusterPath(path), mUnderlying(underlying)
      60            4 :     {}
      61              : 
      62              :     CHIP_ERROR Startup(ServerClusterContext & context) override;
      63              :     void Shutdown(ClusterShutdownType type) override;
      64              :     [[nodiscard]] Span<const ConcreteClusterPath> GetPaths() const override;
      65              :     [[nodiscard]] DataVersion GetDataVersion(const ConcreteClusterPath & path) const override;
      66              :     [[nodiscard]] BitFlags<DataModel::ClusterQualityFlags> GetClusterFlags(const ConcreteClusterPath & path) const override;
      67              :     DataModel::ActionReturnStatus WriteAttribute(const DataModel::WriteAttributeRequest & request,
      68              :                                                  AttributeValueDecoder & decoder) override;
      69              :     void ListAttributeWriteNotification(const ConcreteAttributePath & path, DataModel::ListWriteOperation opType,
      70              :                                         FabricIndex accessingFabric) override;
      71              :     DataModel::ActionReturnStatus ReadAttribute(const DataModel::ReadAttributeRequest & request,
      72              :                                                 AttributeValueEncoder & encoder) override;
      73              :     CHIP_ERROR Attributes(const ConcreteClusterPath & path, ReadOnlyBufferBuilder<DataModel::AttributeEntry> & builder) override;
      74              :     CHIP_ERROR EventInfo(const ConcreteEventPath & path, DataModel::EventEntry & eventInfo) override;
      75              :     std::optional<DataModel::ActionReturnStatus> InvokeCommand(const DataModel::InvokeRequest & request,
      76              :                                                                chip::TLV::TLVReader & input_arguments,
      77              :                                                                CommandHandler * handler) override;
      78              :     CHIP_ERROR AcceptedCommands(const ConcreteClusterPath & path,
      79              :                                 ReadOnlyBufferBuilder<DataModel::AcceptedCommandEntry> & builder) override;
      80              :     CHIP_ERROR GeneratedCommands(const ConcreteClusterPath & path, ReadOnlyBufferBuilder<CommandId> & builder) override;
      81              : 
      82              : protected:
      83              :     const ConcreteClusterPath mClusterPath;
      84              :     ServerClusterInterface & mUnderlying;
      85              : 
      86              :     // Cluster context, set on Startup and reset to nullptr on shutdown.
      87              :     ServerClusterContext * mContext = nullptr;
      88              : 
      89              :     // A data version increment for when the extension's data changes.
      90              :     // Since data version is explicitly random to start and wraps, the extension's
      91              :     // version is computed as "underlying version + delta".
      92              :     DataVersion mVersionDelta = 0;
      93              : 
      94              :     /// Mark the given attribute as changed:
      95              :     ///   - calls the underlying context if available (i.e. make sure reporting works)
      96              :     ///   - updates internal version delta
      97              :     void NotifyAttributeChanged(AttributeId id);
      98              : };
      99              : 
     100              : } // namespace chip::app