Optimize bluetooth_proxy memory copy and reduce reallocs (#8723)

esphome/components/bluetooth_proxy/bluetooth_connection.cpp

@@ -73,9 +73,8 @@ bool BluetoothConnection::gattc_event_handler(esp_gattc_cb_event_t event, esp_ga
       resp.address = this->address_;
       resp.handle = param->read.handle;
       resp.data.reserve(param->read.value_len);
-      for (uint16_t i = 0; i < param->read.value_len; i++) {
+      // Use bulk insert instead of individual push_backs
-        resp.data.push_back(param->read.value[i]);
+      resp.data.insert(resp.data.end(), param->read.value, param->read.value + param->read.value_len);
-      }
       this->proxy_->get_api_connection()->send_bluetooth_gatt_read_response(resp);
       break;
     }
@@ -127,9 +126,8 @@ bool BluetoothConnection::gattc_event_handler(esp_gattc_cb_event_t event, esp_ga
       resp.address = this->address_;
       resp.handle = param->notify.handle;
       resp.data.reserve(param->notify.value_len);
-      for (uint16_t i = 0; i < param->notify.value_len; i++) {
+      // Use bulk insert instead of individual push_backs
-        resp.data.push_back(param->notify.value[i]);
+      resp.data.insert(resp.data.end(), param->notify.value, param->notify.value + param->notify.value_len);
-      }
       this->proxy_->get_api_connection()->send_bluetooth_gatt_notify_data_response(resp);
       break;
     }

esphome/components/bluetooth_proxy/bluetooth_proxy.cpp

@@ -56,6 +56,9 @@ bool BluetoothProxy::parse_devices(esp_ble_gap_cb_param_t::ble_scan_result_evt_p
     return false;
 
   api::BluetoothLERawAdvertisementsResponse resp;
+  // Pre-allocate the advertisements vector to avoid reallocations
+  resp.advertisements.reserve(count);
+
   for (size_t i = 0; i < count; i++) {
     auto &result = advertisements[i];
     api::BluetoothLERawAdvertisement adv;
@@ -65,9 +68,8 @@ bool BluetoothProxy::parse_devices(esp_ble_gap_cb_param_t::ble_scan_result_evt_p
 
     uint8_t length = result.adv_data_len + result.scan_rsp_len;
     adv.data.reserve(length);
-    for (uint16_t i = 0; i < length; i++) {
+    // Use a bulk insert instead of individual push_backs
-      adv.data.push_back(result.ble_adv[i]);
+    adv.data.insert(adv.data.end(), &result.ble_adv[0], &result.ble_adv[length]);
-    }
 
     resp.advertisements.push_back(std::move(adv));
 
@@ -85,21 +87,34 @@ void BluetoothProxy::send_api_packet_(const esp32_ble_tracker::ESPBTDevice &devi
   if (!device.get_name().empty())
     resp.name = device.get_name();
   resp.rssi = device.get_rssi();
-  for (auto uuid : device.get_service_uuids()) {
+
+  // Pre-allocate vectors based on known sizes
+  auto service_uuids = device.get_service_uuids();
+  resp.service_uuids.reserve(service_uuids.size());
+  for (auto uuid : service_uuids) {
     resp.service_uuids.push_back(uuid.to_string());
   }
-  for (auto &data : device.get_service_datas()) {
+
+  // Pre-allocate service data vector
+  auto service_datas = device.get_service_datas();
+  resp.service_data.reserve(service_datas.size());
+  for (auto &data : service_datas) {
     api::BluetoothServiceData service_data;
     service_data.uuid = data.uuid.to_string();
     service_data.data.assign(data.data.begin(), data.data.end());
     resp.service_data.push_back(std::move(service_data));
   }
-  for (auto &data : device.get_manufacturer_datas()) {
+
+  // Pre-allocate manufacturer data vector
+  auto manufacturer_datas = device.get_manufacturer_datas();
+  resp.manufacturer_data.reserve(manufacturer_datas.size());
+  for (auto &data : manufacturer_datas) {
     api::BluetoothServiceData manufacturer_data;
     manufacturer_data.uuid = data.uuid.to_string();
     manufacturer_data.data.assign(data.data.begin(), data.data.end());
     resp.manufacturer_data.push_back(std::move(manufacturer_data));
   }
+
   this->api_connection_->send_bluetooth_le_advertisement(resp);
 }
 
@@ -161,11 +176,27 @@ void BluetoothProxy::loop() {
       }
       api::BluetoothGATTGetServicesResponse resp;
       resp.address = connection->get_address();
+      resp.services.reserve(1);  // Always one service per response in this implementation
       api::BluetoothGATTService service_resp;
       service_resp.uuid = get_128bit_uuid_vec(service_result.uuid);
       service_resp.handle = service_result.start_handle;
       uint16_t char_offset = 0;
       esp_gattc_char_elem_t char_result;
+      // Get the number of characteristics directly with one call
+      uint16_t total_char_count = 0;
+      esp_gatt_status_t char_count_status = esp_ble_gattc_get_attr_count(
+          connection->get_gattc_if(), connection->get_conn_id(), ESP_GATT_DB_CHARACTERISTIC,
+          service_result.start_handle, service_result.end_handle, 0, &total_char_count);
+
+      if (char_count_status == ESP_GATT_OK && total_char_count > 0) {
+        // Only reserve if we successfully got a count
+        service_resp.characteristics.reserve(total_char_count);
+      } else if (char_count_status != ESP_GATT_OK) {
+        ESP_LOGW(TAG, "[%d] [%s] Error getting characteristic count, status=%d", connection->get_connection_index(),
+                 connection->address_str().c_str(), char_count_status);
+      }
+
+      // Now process characteristics
       while (true) {  // characteristics
         uint16_t char_count = 1;
         esp_gatt_status_t char_status = esp_ble_gattc_get_all_char(
@@ -187,6 +218,23 @@ void BluetoothProxy::loop() {
         characteristic_resp.handle = char_result.char_handle;
         characteristic_resp.properties = char_result.properties;
         char_offset++;
+
+        // Get the number of descriptors directly with one call
+        uint16_t total_desc_count = 0;
+        esp_gatt_status_t desc_count_status =
+            esp_ble_gattc_get_attr_count(connection->get_gattc_if(), connection->get_conn_id(), ESP_GATT_DB_DESCRIPTOR,
+                                         char_result.char_handle, service_result.end_handle, 0, &total_desc_count);
+
+        if (desc_count_status == ESP_GATT_OK && total_desc_count > 0) {
+          // Only reserve if we successfully got a count
+          characteristic_resp.descriptors.reserve(total_desc_count);
+        } else if (desc_count_status != ESP_GATT_OK) {
+          ESP_LOGW(TAG, "[%d] [%s] Error getting descriptor count for char handle %d, status=%d",
+                   connection->get_connection_index(), connection->address_str().c_str(), char_result.char_handle,
+                   desc_count_status);
+        }
+
+        // Now process descriptors
         uint16_t desc_offset = 0;
         esp_gattc_descr_elem_t desc_result;
         while (true) {  // descriptors