mirror/esphome
1
0
Fork 0
mirror of https://github.com/esphome/esphome.git synced 2026-02-18 15:35:59 -07:00
Code Issues Packages Projects Releases Wiki Activity

[mdns] Use stack buffer for txt records on ESP32 (#13401)

Browse Source
This commit is contained in:
J. Nick Koston
2026-01-20 17:52:43 -10:00
committed by GitHub
parent 54d6825323
commit fbde91358c
2 changed files with 12 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
esphome/components/mdns/mdns_esp32.cpp
View File

@@ -24,13 +24,14 @@ static void register_esp32(MDNSComponent *comp, StaticVector<MDNSService, MDNS_S
mdns_instance_name_set(hostname);
for (const auto &service : services) {
auto txt_records = std::make_unique<mdns_txt_item_t[]>(service.txt_records.size());
// Stack buffer for up to 16 txt records, heap fallback for more
SmallBufferWithHeapFallback<16, mdns_txt_item_t> txt_records(service.txt_records.size());
for (size_t i = 0; i < service.txt_records.size(); i++) {
const auto &record = service.txt_records[i];
// key and value are either compile-time string literals in flash or pointers to dynamic_txt_values_
// Both remain valid for the lifetime of this function, and ESP-IDF makes internal copies
txt_records[i].key = MDNS_STR_ARG(record.key);
txt_records[i].value = MDNS_STR_ARG(record.value);
txt_records.get()[i].key = MDNS_STR_ARG(record.key);
txt_records.get()[i].value = MDNS_STR_ARG(record.value);
}
uint16_t port = const_cast<TemplatableValue<uint16_t> &>(service.port).value();
err = mdns_service_add(nullptr, MDNS_STR_ARG(service.service_type), MDNS_STR_ARG(service.proto), port,

14
esphome/core/helpers.h
View File

@@ -371,13 +371,15 @@ template<typename T> class FixedVector {
/// @brief Helper class for efficient buffer allocation - uses stack for small sizes, heap for large
/// This is useful when most operations need a small buffer but occasionally need larger ones.
/// The stack buffer avoids heap allocation in the common case, while heap fallback handles edge cases.
template<size_t STACK_SIZE> class SmallBufferWithHeapFallback {
/// @tparam STACK_SIZE Number of elements in the stack buffer
/// @tparam T Element type (default: uint8_t)
template<size_t STACK_SIZE, typename T = uint8_t> class SmallBufferWithHeapFallback {
public:
explicit SmallBufferWithHeapFallback(size_t size) {
if (size <= STACK_SIZE) {
this->buffer_ = this->stack_buffer_;
} else {
this->heap_buffer_ = new uint8_t[size];
this->heap_buffer_ = new T[size];
this->buffer_ = this->heap_buffer_;
}
}
@@ -389,12 +391,12 @@ template<size_t STACK_SIZE> class SmallBufferWithHeapFallback {
SmallBufferWithHeapFallback(SmallBufferWithHeapFallback &&) = delete;
SmallBufferWithHeapFallback &operator=(SmallBufferWithHeapFallback &&) = delete;
uint8_t *get() { return this->buffer_; }
T *get() { return this->buffer_; }
private:
uint8_t stack_buffer_[STACK_SIZE];
uint8_t *heap_buffer_{nullptr};
uint8_t *buffer_;
T stack_buffer_[STACK_SIZE];
T *heap_buffer_{nullptr};
T *buffer_;
};
///@}