Save flash on generated struct encoding logic

src/app/data-model/WrappedStructEncoder.h

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2023 Project CHIP Authors
+ * All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <app/data-model/Encode.h>
+
+#include <lib/core/CHIPError.h>
+#include <lib/core/DataModelTypes.h>
+#include <lib/core/TLV.h>
+
+#include <utility>
+
+namespace chip {
+namespace app {
+namespace DataModel {
+
+class WrappedStructEncoder
+{
+public:
+ WrappedStructEncoder(TLV::TLVWriter & writer, TLV::Tag outerTag) : mWriter(writer)
+ {
+ mLastError = mWriter.StartContainer(outerTag, TLV::kTLVType_Structure, mOuter);
+ }
+
+ template <typename... Args>
+ void Encode(uint8_t contextTag, Args &&... args)
+ {
+ VerifyOrReturn(mLastError == CHIP_NO_ERROR);
+ mLastError = DataModel::Encode(mWriter, TLV::ContextTag(contextTag), std::forward<Args>(args)...);
+ }
+
+ CHIP_ERROR Finalize()
+ {
+ if (mLastError == CHIP_NO_ERROR)
+ {
+ mLastError = mWriter.EndContainer(mOuter);
+ }
+ return mLastError;
+ }
+
+private:
+ TLV::TLVWriter & mWriter;
+ CHIP_ERROR mLastError = CHIP_NO_ERROR;
+ TLV::TLVType mOuter;
+};
+
+} // namespace DataModel
+} // namespace app
+} // namespace chip

src/app/zap-templates/partials/cluster-objects-struct.zapt

@@ -64,6 +64,7 @@ namespace {{asUpperCamelCase name}} {
 
 } // namespace {{asUpperCamelCase name}}
 {{else}}
+
 namespace {{asUpperCamelCase name}} {
 {{#if isFabricScoped}}
 CHIP_ERROR Type::EncodeForWrite(TLV::TLVWriter & aWriter, TLV::Tag aTag) const
@@ -81,34 +82,33 @@ CHIP_ERROR Type::DoEncode(TLV::TLVWriter & aWriter, TLV::Tag aTag, const Optiona
  {{#if struct_has_fabric_sensitive_fields}}
  bool includeSensitive = !aAccessingFabricIndex.HasValue() || (aAccessingFabricIndex.Value() == fabricIndex);
  {{/if}}
- TLV::TLVType outer;
- ReturnErrorOnFailure(aWriter.StartContainer(aTag, TLV::kTLVType_Structure, outer));
+
+ DataModel::WrappedStructEncoder encoder{aWriter, aTag};
+
  {{#zcl_struct_items}}
  {{#if (is_num_equal fieldIdentifier 254)}}
  if (aAccessingFabricIndex.HasValue()) {
- ReturnErrorOnFailure(DataModel::Encode(aWriter, TLV::ContextTag(Fields::k{{asUpperCamelCase label}}), {{asLowerCamelCase label}}));
+ encoder.Encode(to_underlying(Fields::k{{asUpperCamelCase label}}), {{asLowerCamelCase label}});
  }
  {{else if isFabricSensitive}}
  if (includeSensitive) {
-  ReturnErrorOnFailure(DataModel::Encode(aWriter, TLV::ContextTag(Fields::k{{asUpperCamelCase label}}), {{asLowerCamelCase label}}));
+ encoder.Encode(to_underlying(Fields::k{{asUpperCamelCase label}}), {{asLowerCamelCase label}});
  }
  {{else}}
- ReturnErrorOnFailure(DataModel::Encode(aWriter, TLV::ContextTag(Fields::k{{asUpperCamelCase label}}), {{asLowerCamelCase label}}));
+ encoder.Encode(to_underlying(Fields::k{{asUpperCamelCase label}}), {{asLowerCamelCase label}});
  {{/if}}
  {{/zcl_struct_items}}
- ReturnErrorOnFailure(aWriter.EndContainer(outer));
- return CHIP_NO_ERROR;
+
+ return encoder.Finalize();
 }
 {{else}}
 CHIP_ERROR Type::Encode(TLV::TLVWriter & aWriter, TLV::Tag aTag) const
 {
- TLV::TLVType outer;
- ReturnErrorOnFailure(aWriter.StartContainer(aTag, TLV::kTLVType_Structure, outer));
+ DataModel::WrappedStructEncoder encoder{aWriter, aTag};
  {{#zcl_struct_items}}
- ReturnErrorOnFailure(DataModel::Encode(aWriter, TLV::ContextTag(Fields::k{{asUpperCamelCase label}}), {{asLowerCamelCase label}}));
+ encoder.Encode(to_underlying(Fields::k{{asUpperCamelCase label}}), {{asLowerCamelCase label}});
  {{/zcl_struct_items}}
- ReturnErrorOnFailure(aWriter.EndContainer(outer));
- return CHIP_NO_ERROR;
+ return encoder.Finalize();
 }
 {{/if}}
 

src/app/zap-templates/templates/app/cluster-objects-src.zapt

@@ -1,6 +1,8 @@
 {{> header}}
 
+#include <app/data-model/WrappedStructEncoder.h>
 #include <app-common/zap-generated/cluster-objects.h>
+
 #include <variant>
 
 namespace chip {
@@ -80,12 +82,11 @@ namespace Commands {
 {{#zcl_commands}}
 namespace {{asUpperCamelCase name}} {
 CHIP_ERROR Type::Encode(TLV::TLVWriter & aWriter, TLV::Tag aTag) const{
- TLV::TLVType outer;
- ReturnErrorOnFailure(aWriter.StartContainer(aTag, TLV::kTLVType_Structure, outer));
+ DataModel::WrappedStructEncoder encoder{aWriter, aTag};
  {{#zcl_command_arguments}}
- ReturnErrorOnFailure(DataModel::Encode(aWriter, TLV::ContextTag(Fields::k{{asUpperCamelCase label}}), {{asLowerCamelCase label}}));
+ encoder.Encode(to_underlying(Fields::k{{asUpperCamelCase label}}), {{asLowerCamelCase label}});
  {{/zcl_command_arguments}}
- return aWriter.EndContainer(outer);
+ return encoder.Finalize();
 }
 
 CHIP_ERROR DecodableType::Decode(TLV::TLVReader &reader) {