[debug] Use stack buffers with buf_append helper instead of std::string (#13020)

esphome/components/debug/debug_libretiny.cpp

@@ -7,31 +7,43 @@ namespace debug {
 
 static const char *const TAG = "debug";
 
-std::string DebugComponent::get_reset_reason_() { return lt_get_reboot_reason_name(lt_get_reboot_reason()); }
+const char *DebugComponent::get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) {
+  // Return the static string directly
+  return lt_get_reboot_reason_name(lt_get_reboot_reason());
+}
+
+const char *DebugComponent::get_wakeup_cause_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) { return ""; }
 
 uint32_t DebugComponent::get_free_heap_() { return lt_heap_get_free(); }
 
-void DebugComponent::get_device_info_(std::string &device_info) {
-  std::string reset_reason = get_reset_reason_();
+size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE> buffer, size_t pos) {
+  constexpr size_t size = DEVICE_INFO_BUFFER_SIZE;
+  char *buf = buffer.data();
+
+  char reason_buffer[RESET_REASON_BUFFER_SIZE];
+  const char *reset_reason = get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE>(reason_buffer));
+  uint32_t flash_kib = lt_flash_get_size() / 1024;
+  uint32_t ram_kib = lt_ram_get_size() / 1024;
+  uint32_t mac_id = lt_cpu_get_mac_id();
+
   ESP_LOGD(TAG,
            "LibreTiny Version: %s\n"
            "Chip: %s (%04x) @ %u MHz\n"
-           "Chip ID: 0x%06X\n"
+           "Chip ID: 0x%06" PRIX32 "\n"
            "Board: %s\n"
-           "Flash: %u KiB / RAM: %u KiB\n"
+           "Flash: %" PRIu32 " KiB / RAM: %" PRIu32 " KiB\n"
            "Reset Reason: %s",
-           lt_get_version(), lt_cpu_get_model_name(), lt_cpu_get_model(), lt_cpu_get_freq_mhz(), lt_cpu_get_mac_id(),
-           lt_get_board_code(), lt_flash_get_size() / 1024, lt_ram_get_size() / 1024, reset_reason.c_str());
+           lt_get_version(), lt_cpu_get_model_name(), lt_cpu_get_model(), lt_cpu_get_freq_mhz(), mac_id,
+           lt_get_board_code(), flash_kib, ram_kib, reset_reason);
 
-  device_info += "|Version: ";
-  device_info += LT_BANNER_STR + 10;
-  device_info += "|Reset Reason: ";
-  device_info += reset_reason;
-  device_info += "|Chip Name: ";
-  device_info += lt_cpu_get_model_name();
-  device_info += "|Chip ID: 0x" + format_hex(lt_cpu_get_mac_id());
-  device_info += "|Flash: " + to_string(lt_flash_get_size() / 1024) + " KiB";
-  device_info += "|RAM: " + to_string(lt_ram_get_size() / 1024) + " KiB";
+  pos = buf_append(buf, size, pos, "|Version: %s", LT_BANNER_STR + 10);
+  pos = buf_append(buf, size, pos, "|Reset Reason: %s", reset_reason);
+  pos = buf_append(buf, size, pos, "|Chip Name: %s", lt_cpu_get_model_name());
+  pos = buf_append(buf, size, pos, "|Chip ID: 0x%06" PRIX32, mac_id);
+  pos = buf_append(buf, size, pos, "|Flash: %" PRIu32 " KiB", flash_kib);
+  pos = buf_append(buf, size, pos, "|RAM: %" PRIu32 " KiB", ram_kib);
+
+  return pos;
 }
 
 void DebugComponent::update_platform_() {