Upgrading notes

API changes and code migration

CommandHandler

CommandHandler ability to directly invoke Prepare/TLV-Write/Finish cycles has been changed to only expose AddResponse/AddStatus/AddClusterSpecific*.

Original versions of CommandHandler exposed the following low-level implementation-specific methods: PrepareCommand, PrepareInvokeResponseCommand, GetCommandDataIBTLVWriter and FinishCommand. These are not exposed anymore and instead one should use AddResponse or AddResponseData. When using an EncodableToTLV argument, the same functionality should be achievable.

Example

Before:


const CommandHandler::InvokeResponseParameters prepareParams(requestPath); ReturnOnFailure(commandHandler->PrepareInvokeResponseCommand(path, prepareParams)); TLV::TLVWriter *writer = commandHandler->GetCommandDataIBTLVWriter(); ReturnOnFailure(writer->Put(chip::TLV::ContextTag(1), 123)); ReturnOnFailure(writer->Put(chip::TLV::ContextTag(2), 234)); return commandHandler->FinishCommand();

After:


class ReplyEncoder : public DataModel::EncodableToTLV { public: CHIP_ERROR EncodeTo(TLV::TLVWriter & writer, TLV::Tag tag) const override { TLV::TLVType outerType; ReturnErrorOnFailure(writer.StartContainer(tag, TLV::kTLVType_Structure, outerType)); ReturnOnFailure(writer.Put(chip::TLV::ContextTag(1), 123)); ReturnOnFailure(writer.Put(chip::TLV::ContextTag(2), 234)); return writer.EndContainer(outerType); } }; // ... ReplyEncoder replyEncoder; commandHandler->AddResponse(path, kReplyCommandId, replyEncoder); // or if error handling is implemented: // // ReturnErrorOnFailure(commandHandler->AddResponseData(path, kReplyCommandId, replyEncoder)); // // In many cases error recovery from not being able to send a reply is not easy or expected, // so code does AddResponse rather than AddResponseData.

CommandHandlerInterface in chip::app::InteractionModelEngine

Command handler lists were placed in a separate registry class that is independent of the InteractionModelEngine class.

The following replacements exist:

  • chip::app::InteractionModelEngine::RegisterCommandHandler replaced by chip::app::CommandHandlerInterfaceRegistry::RegisterCommandHandler
  • chip::app::InteractionModelEngine::UnregisterCommandHandler replaced by chip::app::CommandHandlerInterfaceRegistry::UnregisterCommandHandler
  • chip::app::InteractionModelEngine::FindCommandHandler replaced by chip::app::CommandHandlerInterfaceRegistry::GetCommandHandler
  • chip::app::InteractionModelEngine::UnregisterCommandHandlers replaced by chip::app::CommandHandlerInterfaceRegistry::UnregisterAllCommandHandlersForEndpoint