| // Copyright 2020 The Pigweed Authors |
| // |
| // 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 |
| // |
| // https://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. |
| |
| #include "pw_rpc/internal/packet.h" |
| |
| #include "pw_protobuf/decoder.h" |
| |
| namespace pw::rpc::internal { |
| |
| using std::byte; |
| |
| Packet Packet::FromBuffer(span<const byte> data) { |
| PacketType type = PacketType::RPC; |
| uint32_t channel_id = 0; |
| uint32_t service_id = 0; |
| uint32_t method_id = 0; |
| span<const byte> payload; |
| Status status; |
| |
| uint32_t value; |
| protobuf::Decoder decoder(data); |
| |
| while (decoder.Next().ok()) { |
| RpcPacket::Fields field = |
| static_cast<RpcPacket::Fields>(decoder.FieldNumber()); |
| uint32_t proto_value = 0; |
| |
| switch (field) { |
| case RpcPacket::Fields::TYPE: |
| decoder.ReadUint32(&proto_value); |
| type = static_cast<PacketType>(proto_value); |
| break; |
| |
| case RpcPacket::Fields::CHANNEL_ID: |
| decoder.ReadUint32(&channel_id); |
| break; |
| |
| case RpcPacket::Fields::SERVICE_ID: |
| decoder.ReadUint32(&service_id); |
| break; |
| |
| case RpcPacket::Fields::METHOD_ID: |
| decoder.ReadUint32(&method_id); |
| break; |
| |
| case RpcPacket::Fields::PAYLOAD: |
| decoder.ReadBytes(&payload); |
| break; |
| |
| case RpcPacket::Fields::STATUS: |
| decoder.ReadUint32(&value); |
| status = static_cast<Status::Code>(value); |
| break; |
| } |
| } |
| |
| return Packet(type, channel_id, service_id, method_id, payload, status); |
| } |
| |
| StatusWithSize Packet::Encode(span<byte> buffer) const { |
| pw::protobuf::NestedEncoder encoder(buffer); |
| RpcPacket::Encoder rpc_packet(&encoder); |
| |
| // The payload is encoded first, as it may share the encode buffer. |
| rpc_packet.WritePayload(payload_); |
| |
| rpc_packet.WriteType(type_); |
| rpc_packet.WriteChannelId(channel_id_); |
| rpc_packet.WriteServiceId(service_id_); |
| rpc_packet.WriteMethodId(method_id_); |
| rpc_packet.WriteStatus(status_); |
| |
| span<const byte> proto; |
| if (Status status = encoder.Encode(&proto); !status.ok()) { |
| return StatusWithSize(status, 0); |
| } |
| |
| return StatusWithSize(proto.size()); |
| } |
| |
| span<byte> Packet::PayloadUsableSpace(span<byte> buffer) const { |
| size_t reserved_size = 0; |
| |
| reserved_size += 1; // channel_id key |
| reserved_size += varint::EncodedSize(channel_id()); |
| reserved_size += 1; // service_id key |
| reserved_size += varint::EncodedSize(service_id()); |
| reserved_size += 1; // method_id key |
| reserved_size += varint::EncodedSize(method_id()); |
| |
| // Packet type always takes two bytes to encode (varint key + varint enum). |
| reserved_size += 2; |
| |
| // Status field always takes two bytes to encode (varint key + varint status). |
| reserved_size += 2; |
| |
| // Payload field takes at least two bytes to encode (varint key + length). |
| reserved_size += 2; |
| |
| return reserved_size <= buffer.size() ? buffer.subspan(reserved_size) |
| : span<byte>(); |
| } |
| |
| } // namespace pw::rpc::internal |