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Code Issues Releases Wiki Activity

Use std::span to eliminate heap allocation for single-packet API transmissions (#9313)

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This commit is contained in:
J. Nick Koston
2025-07-06 21:53:23 -05:00
committed by GitHub
parent a303f93236
commit 765793505d
2 changed files with 36 additions and 57 deletions
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86
esphome/components/api/api_frame_helper.cpp
View File

@@ -614,20 +614,14 @@ APIError APINoiseFrameHelper::read_packet(ReadPacketBuffer *buffer) {
return APIError::OK;
}
APIError APINoiseFrameHelper::write_protobuf_packet(uint16_t type, ProtoWriteBuffer buffer) {
std::vector<uint8_t> *raw_buffer = buffer.get_buffer();
uint16_t payload_len = static_cast<uint16_t>(raw_buffer->size() - frame_header_padding_);
// Resize to include MAC space (required for Noise encryption)
raw_buffer->resize(raw_buffer->size() + frame_footer_size_);
// Use write_protobuf_packets with a single packet
std::vector<PacketInfo> packets;
packets.emplace_back(type, 0, payload_len);
return write_protobuf_packets(buffer, packets);
buffer.get_buffer()->resize(buffer.get_buffer()->size() + frame_footer_size_);
PacketInfo packet{type, 0,
static_cast<uint16_t>(buffer.get_buffer()->size() - frame_header_padding_ - frame_footer_size_)};
return write_protobuf_packets(buffer, std::span<const PacketInfo>(&packet, 1));
}
APIError APINoiseFrameHelper::write_protobuf_packets(ProtoWriteBuffer buffer, const std::vector<PacketInfo> &packets) {
APIError APINoiseFrameHelper::write_protobuf_packets(ProtoWriteBuffer buffer, std::span<const PacketInfo> packets) {
APIError aerr = state_action_();
if (aerr != APIError::OK) {
return aerr;
@@ -642,18 +636,15 @@ APIError APINoiseFrameHelper::write_protobuf_packets(ProtoWriteBuffer buffer, co
}
std::vector<uint8_t> *raw_buffer = buffer.get_buffer();
uint8_t *buffer_data = raw_buffer->data(); // Cache buffer pointer
this->reusable_iovs_.clear();
this->reusable_iovs_.reserve(packets.size());
// We need to encrypt each packet in place
for (const auto &packet : packets) {
uint16_t type = packet.message_type;
uint16_t offset = packet.offset;
uint16_t payload_len = packet.payload_size;
uint16_t msg_len = 4 + payload_len; // type(2) + data_len(2) + payload
// The buffer already has padding at offset
uint8_t *buf_start = raw_buffer->data() + offset;
uint8_t *buf_start = buffer_data + packet.offset;
// Write noise header
buf_start[0] = 0x01; // indicator
@@ -661,10 +652,10 @@ APIError APINoiseFrameHelper::write_protobuf_packets(ProtoWriteBuffer buffer, co
// Write message header (to be encrypted)
const uint8_t msg_offset = 3;
buf_start[msg_offset + 0] = (uint8_t) (type >> 8); // type high byte
buf_start[msg_offset + 1] = (uint8_t) type; // type low byte
buf_start[msg_offset + 2] = (uint8_t) (payload_len >> 8); // data_len high byte
buf_start[msg_offset + 3] = (uint8_t) payload_len; // data_len low byte
buf_start[msg_offset] = static_cast<uint8_t>(packet.message_type >> 8); // type high byte
buf_start[msg_offset + 1] = static_cast<uint8_t>(packet.message_type); // type low byte
buf_start[msg_offset + 2] = static_cast<uint8_t>(packet.payload_size >> 8); // data_len high byte
buf_start[msg_offset + 3] = static_cast<uint8_t>(packet.payload_size); // data_len low byte
// payload data is already in the buffer starting at offset + 7
// Make sure we have space for MAC
@@ -673,7 +664,8 @@ APIError APINoiseFrameHelper::write_protobuf_packets(ProtoWriteBuffer buffer, co
// Encrypt the message in place
NoiseBuffer mbuf;
noise_buffer_init(mbuf);
noise_buffer_set_inout(mbuf, buf_start + msg_offset, msg_len, msg_len + frame_footer_size_);
noise_buffer_set_inout(mbuf, buf_start + msg_offset, 4 + packet.payload_size,
4 + packet.payload_size + frame_footer_size_);
int err = noise_cipherstate_encrypt(send_cipher_, &mbuf);
if (err != 0) {
@@ -683,14 +675,12 @@ APIError APINoiseFrameHelper::write_protobuf_packets(ProtoWriteBuffer buffer, co
}
// Fill in the encrypted size
buf_start[1] = (uint8_t) (mbuf.size >> 8);
buf_start[2] = (uint8_t) mbuf.size;
buf_start[1] = static_cast<uint8_t>(mbuf.size >> 8);
buf_start[2] = static_cast<uint8_t>(mbuf.size);
// Add iovec for this encrypted packet
struct iovec iov;
iov.iov_base = buf_start;
iov.iov_len = 3 + mbuf.size; // indicator + size + encrypted data
this->reusable_iovs_.push_back(iov);
this->reusable_iovs_.push_back(
{buf_start, static_cast<size_t>(3 + mbuf.size)}); // indicator + size + encrypted data
}
// Send all encrypted packets in one writev call
@@ -1029,18 +1019,11 @@ APIError APIPlaintextFrameHelper::read_packet(ReadPacketBuffer *buffer) {
return APIError::OK;
}
APIError APIPlaintextFrameHelper::write_protobuf_packet(uint16_t type, ProtoWriteBuffer buffer) {
std::vector<uint8_t> *raw_buffer = buffer.get_buffer();
uint16_t payload_len = static_cast<uint16_t>(raw_buffer->size() - frame_header_padding_);
// Use write_protobuf_packets with a single packet
std::vector<PacketInfo> packets;
packets.emplace_back(type, 0, payload_len);
return write_protobuf_packets(buffer, packets);
PacketInfo packet{type, 0, static_cast<uint16_t>(buffer.get_buffer()->size() - frame_header_padding_)};
return write_protobuf_packets(buffer, std::span<const PacketInfo>(&packet, 1));
}
APIError APIPlaintextFrameHelper::write_protobuf_packets(ProtoWriteBuffer buffer,
const std::vector<PacketInfo> &packets) {
APIError APIPlaintextFrameHelper::write_protobuf_packets(ProtoWriteBuffer buffer, std::span<const PacketInfo> packets) {
if (state_ != State::DATA) {
return APIError::BAD_STATE;
}
@@ -1050,17 +1033,15 @@ APIError APIPlaintextFrameHelper::write_protobuf_packets(ProtoWriteBuffer buffer
}
std::vector<uint8_t> *raw_buffer = buffer.get_buffer();
uint8_t *buffer_data = raw_buffer->data(); // Cache buffer pointer
this->reusable_iovs_.clear();
this->reusable_iovs_.reserve(packets.size());
for (const auto &packet : packets) {
uint16_t type = packet.message_type;
uint16_t offset = packet.offset;
uint16_t payload_len = packet.payload_size;
// Calculate varint sizes for header layout
uint8_t size_varint_len = api::ProtoSize::varint(static_cast<uint32_t>(payload_len));
uint8_t type_varint_len = api::ProtoSize::varint(static_cast<uint32_t>(type));
uint8_t size_varint_len = api::ProtoSize::varint(static_cast<uint32_t>(packet.payload_size));
uint8_t type_varint_len = api::ProtoSize::varint(static_cast<uint32_t>(packet.message_type));
uint8_t total_header_len = 1 + size_varint_len + type_varint_len;
// Calculate where to start writing the header
@@ -1088,23 +1069,20 @@ APIError APIPlaintextFrameHelper::write_protobuf_packets(ProtoWriteBuffer buffer
//
// The message starts at offset + frame_header_padding_
// So we write the header starting at offset + frame_header_padding_ - total_header_len
uint8_t *buf_start = raw_buffer->data() + offset;
uint8_t *buf_start = buffer_data + packet.offset;
uint32_t header_offset = frame_header_padding_ - total_header_len;
// Write the plaintext header
buf_start[header_offset] = 0x00; // indicator
// Encode size varint directly into buffer
ProtoVarInt(payload_len).encode_to_buffer_unchecked(buf_start + header_offset + 1, size_varint_len);
// Encode type varint directly into buffer
ProtoVarInt(type).encode_to_buffer_unchecked(buf_start + header_offset + 1 + size_varint_len, type_varint_len);
// Encode varints directly into buffer
ProtoVarInt(packet.payload_size).encode_to_buffer_unchecked(buf_start + header_offset + 1, size_varint_len);
ProtoVarInt(packet.message_type)
.encode_to_buffer_unchecked(buf_start + header_offset + 1 + size_varint_len, type_varint_len);
// Add iovec for this packet (header + payload)
struct iovec iov;
iov.iov_base = buf_start + header_offset;
iov.iov_len = total_header_len + payload_len;
this->reusable_iovs_.push_back(iov);
this->reusable_iovs_.push_back(
{buf_start + header_offset, static_cast<size_t>(total_header_len + packet.payload_size)});
}
// Send all packets in one writev call

7
esphome/components/api/api_frame_helper.h
View File

@@ -2,6 +2,7 @@
#include <cstdint>
#include <deque>
#include <limits>
#include <span>
#include <utility>
#include <vector>
@@ -101,7 +102,7 @@ class APIFrameHelper {
// Write multiple protobuf packets in a single operation
// packets contains (message_type, offset, length) for each message in the buffer
// The buffer contains all messages with appropriate padding before each
virtual APIError write_protobuf_packets(ProtoWriteBuffer buffer, const std::vector<PacketInfo> &packets) = 0;
virtual APIError write_protobuf_packets(ProtoWriteBuffer buffer, std::span<const PacketInfo> packets) = 0;
// Get the frame header padding required by this protocol
virtual uint8_t frame_header_padding() = 0;
// Get the frame footer size required by this protocol
@@ -194,7 +195,7 @@ class APINoiseFrameHelper : public APIFrameHelper {
APIError loop() override;
APIError read_packet(ReadPacketBuffer *buffer) override;
APIError write_protobuf_packet(uint16_t type, ProtoWriteBuffer buffer) override;
APIError write_protobuf_packets(ProtoWriteBuffer buffer, const std::vector<PacketInfo> &packets) override;
APIError write_protobuf_packets(ProtoWriteBuffer buffer, std::span<const PacketInfo> packets) override;
// Get the frame header padding required by this protocol
uint8_t frame_header_padding() override { return frame_header_padding_; }
// Get the frame footer size required by this protocol
@@ -248,7 +249,7 @@ class APIPlaintextFrameHelper : public APIFrameHelper {
APIError loop() override;
APIError read_packet(ReadPacketBuffer *buffer) override;
APIError write_protobuf_packet(uint16_t type, ProtoWriteBuffer buffer) override;
APIError write_protobuf_packets(ProtoWriteBuffer buffer, const std::vector<PacketInfo> &packets) override;
APIError write_protobuf_packets(ProtoWriteBuffer buffer, std::span<const PacketInfo> packets) override;
uint8_t frame_header_padding() override { return frame_header_padding_; }
// Get the frame footer size required by this protocol
uint8_t frame_footer_size() override { return frame_footer_size_; }