137 lines
4.3 KiB
C++
137 lines
4.3 KiB
C++
// Copyright 2020 The Pigweed Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not
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// use this file except in compliance with the License. You may obtain a copy of
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// the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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// License for the specific language governing permissions and limitations under
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// the License.
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#include "pw_rpc/internal/packet.h"
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#include "pw_protobuf/decoder.h"
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namespace pw::rpc::internal {
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Result<Packet> Packet::FromBuffer(ConstByteSpan data) {
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Packet packet;
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Status status;
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protobuf::Decoder decoder(data);
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while ((status = decoder.Next()).ok()) {
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RpcPacket::Fields field =
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static_cast<RpcPacket::Fields>(decoder.FieldNumber());
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switch (field) {
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case RpcPacket::Fields::TYPE: {
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uint32_t value;
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// A decode error will propagate from Next() and terminate the loop.
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decoder.ReadUint32(&value).IgnoreError();
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packet.set_type(static_cast<PacketType>(value));
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break;
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}
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case RpcPacket::Fields::CHANNEL_ID:
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// A decode error will propagate from Next() and terminate the loop.
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decoder.ReadUint32(&packet.channel_id_).IgnoreError();
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break;
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case RpcPacket::Fields::SERVICE_ID:
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// A decode error will propagate from Next() and terminate the loop.
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decoder.ReadFixed32(&packet.service_id_).IgnoreError();
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break;
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case RpcPacket::Fields::METHOD_ID:
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// A decode error will propagate from Next() and terminate the loop.
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decoder.ReadFixed32(&packet.method_id_).IgnoreError();
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break;
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case RpcPacket::Fields::PAYLOAD:
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// A decode error will propagate from Next() and terminate the loop.
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decoder.ReadBytes(&packet.payload_).IgnoreError();
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break;
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case RpcPacket::Fields::STATUS: {
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uint32_t value;
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// A decode error will propagate from Next() and terminate the loop.
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decoder.ReadUint32(&value).IgnoreError();
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packet.set_status(static_cast<Status::Code>(value));
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break;
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}
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case RpcPacket::Fields::CALL_ID:
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// A decode error will propagate from Next() and terminate the loop.
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decoder.ReadUint32(&packet.call_id_).IgnoreError();
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break;
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}
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}
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if (status.IsDataLoss()) {
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return status;
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}
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// TODO(pwbug/512): CANCEL is equivalent to CLIENT_ERROR with status
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// CANCELLED. Remove this workaround when CANCEL is removed.
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if (packet.type() == PacketType::DEPRECATED_CANCEL) {
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packet.set_status(Status::Cancelled());
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}
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return packet;
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}
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Result<ConstByteSpan> Packet::Encode(ByteSpan buffer) const {
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RpcPacket::MemoryEncoder rpc_packet(buffer);
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// The payload is encoded first, as it may share the encode buffer.
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if (!payload_.empty()) {
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rpc_packet.WritePayload(payload_).IgnoreError();
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}
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rpc_packet.WriteType(type_).IgnoreError();
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rpc_packet.WriteChannelId(channel_id_).IgnoreError();
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rpc_packet.WriteServiceId(service_id_).IgnoreError();
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rpc_packet.WriteMethodId(method_id_).IgnoreError();
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// Status code 0 is OK. In protobufs, 0 is the default int value, so skip
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// encoding it to save two bytes in the output.
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if (status_.code() != 0) {
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rpc_packet.WriteStatus(status_.code()).IgnoreError();
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}
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if (call_id_ != 0) {
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rpc_packet.WriteCallId(call_id_).IgnoreError();
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}
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if (rpc_packet.status().ok()) {
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return ConstByteSpan(rpc_packet);
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}
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return rpc_packet.status();
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}
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size_t Packet::MinEncodedSizeBytes() const {
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size_t reserved_size = 0;
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reserved_size += 1; // channel_id key
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reserved_size += varint::EncodedSize(channel_id());
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reserved_size += 1 + sizeof(uint32_t); // service_id key and fixed32
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reserved_size += 1 + sizeof(uint32_t); // method_id key and fixed32
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// Packet type always takes two bytes to encode (varint key + varint enum).
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reserved_size += 2;
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// Status field takes up to two bytes to encode (varint key + varint status).
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reserved_size += 2;
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// Payload field takes at least two bytes to encode (varint key + length).
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reserved_size += 2;
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return reserved_size;
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}
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} // namespace pw::rpc::internal
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