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/data-model-provider/MetadataTypes.h>
      20              : #include <app/server-cluster/OptionalAttributeSet.h>
      21              : #include <lib/core/CHIPError.h>
      22              : #include <lib/support/ReadOnlyBuffer.h>
      23              : 
      24              : namespace chip {
      25              : namespace app {
      26              : 
      27              : /// Provides a centralized implementation of the very common operation of
      28              : /// appending a list of attributes to a ReadOnlyBufferBuilder.
      29              : ///
      30              : /// The intent is that the more complex logic of `Append` to be shared across
      31              : /// cluster implementations, so that flash size is kept small.
      32              : ///
      33              : /// Append handles both mandatory and optional attributes and also handles
      34              : /// the required auto-add of `GlobalAttributes`.
      35              : class AttributeListBuilder
      36              : {
      37              : public:
      38           25 :     AttributeListBuilder(ReadOnlyBufferBuilder<DataModel::AttributeEntry> & builder) : mBuilder(builder) {}
      39              : 
      40              :     /// Constructs a list of cluster attributes, typically for responding to a
      41              :     /// `ServerClusterInterface::Attributes` call.
      42              :     ///
      43              :     /// It allows for one call that will add to the buffer all of:
      44              :     ///   - mandatoryAttributes (all of them)
      45              :     ///   - optionalAttributes IF AND ONLY IF enabledOptionalAttributes is set for them
      46              :     ///   - GlobalAttributes()  (all of them)
      47              :     CHIP_ERROR Append(Span<const DataModel::AttributeEntry> mandatoryAttributes,
      48              :                       Span<const DataModel::AttributeEntry> optionalAttributes, AttributeSet enabledOptionalAttributes);
      49              : 
      50              :     struct OptionalAttributeEntry
      51              :     {
      52              :         bool enabled;                               // Is this optional attribute enabled?
      53              :         const DataModel::AttributeEntry & metadata; // Metadata for the attribute
      54              :     };
      55              : 
      56              :     /// Appends the given attributes to the builder.
      57              :     ///
      58              :     /// It is very common to have a set of mandatory and a set of optional attributes for a
      59              :     /// cluster. This method allows for a single call to set up all of the given attributes in `builder`:
      60              :     ///   - mandatoryAttributes
      61              :     ///   - optionalAttributes IF AND ONLY IF they are enabled
      62              :     ///   - all of `GlobalAttributes()`
      63              :     ///
      64              :     /// NOTE: initializing separate OptionalAttributeEntry often costs flash. Prefer using AttributeSet if possible
      65              :     ///       (historically shown to consume less flash)
      66              :     CHIP_ERROR Append(Span<const DataModel::AttributeEntry> mandatoryAttributes,
      67              :                       Span<const OptionalAttributeEntry> optionalAttributes);
      68              : 
      69              : private:
      70              :     ReadOnlyBufferBuilder<DataModel::AttributeEntry> & mBuilder;
      71              : };
      72              : 
      73              : } // namespace app
      74              : } // namespace chip