From d5ff8f611785d158889c0af4677e6dd29e686ebf Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Mon, 28 Nov 2022 18:14:29 -1000
Subject: [PATCH] Reduce memory needed to send the services list (#4110)

---
 .../bluetooth_proxy/bluetooth_proxy.cpp       | 62 ++++++++++++++-----
 1 file changed, 45 insertions(+), 17 deletions(-)

diff --git a/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp b/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
index 188e3dd5a5..602edc2fa6 100644
--- a/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
+++ b/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
@@ -86,31 +86,59 @@ void BluetoothProxy::loop() {
       api::BluetoothGATTService service_resp;
       service_resp.uuid = {service->uuid.get_128bit_high(), service->uuid.get_128bit_low()};
       service_resp.handle = service->start_handle;
-      if (!service->parsed)
-        service->parse_characteristics();
-      for (auto &characteristic : service->characteristics) {
+      uint16_t char_offset = 0;
+      esp_gattc_char_elem_t char_result;
+      while (true) {  // characteristics
+        uint16_t char_count = 1;
+        esp_gatt_status_t char_status =
+            esp_ble_gattc_get_all_char(connection->get_gattc_if(), connection->get_conn_id(), service->start_handle,
+                                       service->end_handle, &char_result, &char_count, char_offset);
+        if (char_status == ESP_GATT_INVALID_OFFSET || char_status == ESP_GATT_NOT_FOUND) {
+          break;
+        }
+        if (char_status != ESP_GATT_OK) {
+          ESP_LOGW(TAG, "[%d] [%s] esp_ble_gattc_get_all_char error, status=%d", connection->get_connection_index(),
+                   connection->address_str().c_str(), char_status);
+          break;
+        }
+        if (char_count == 0) {
+          break;
+        }
         api::BluetoothGATTCharacteristic characteristic_resp;
-        characteristic_resp.uuid = {characteristic->uuid.get_128bit_high(), characteristic->uuid.get_128bit_low()};
-        characteristic_resp.handle = characteristic->handle;
-        characteristic_resp.properties = characteristic->properties;
-        if (!characteristic->parsed)
-          characteristic->parse_descriptors();
-        for (auto &descriptor : characteristic->descriptors) {
+        auto char_uuid = espbt::ESPBTUUID::from_uuid(char_result.uuid);
+        characteristic_resp.uuid = {char_uuid.get_128bit_high(), char_uuid.get_128bit_low()};
+        characteristic_resp.handle = char_result.char_handle;
+        characteristic_resp.properties = char_result.properties;
+        char_offset++;
+        uint16_t desc_offset = 0;
+        esp_gattc_descr_elem_t desc_result;
+        while (true) {  // descriptors
+          uint16_t desc_count = 1;
+          esp_gatt_status_t desc_status =
+              esp_ble_gattc_get_all_descr(connection->get_gattc_if(), connection->get_conn_id(),
+                                          char_result.char_handle, &desc_result, &desc_count, desc_offset);
+          if (desc_status == ESP_GATT_INVALID_OFFSET || desc_status == ESP_GATT_NOT_FOUND) {
+            break;
+          }
+          if (desc_status != ESP_GATT_OK) {
+            ESP_LOGW(TAG, "[%d] [%s] esp_ble_gattc_get_all_descr error, status=%d", connection->get_connection_index(),
+                     connection->address_str().c_str(), desc_status);
+            break;
+          }
+          if (desc_count == 0) {
+            break;
+          }
           api::BluetoothGATTDescriptor descriptor_resp;
-          descriptor_resp.uuid = {descriptor->uuid.get_128bit_high(), descriptor->uuid.get_128bit_low()};
-          descriptor_resp.handle = descriptor->handle;
+          auto desc_uuid = espbt::ESPBTUUID::from_uuid(desc_result.uuid);
+          descriptor_resp.uuid = {desc_uuid.get_128bit_high(), desc_uuid.get_128bit_low()};
+          descriptor_resp.handle = desc_result.handle;
           characteristic_resp.descriptors.push_back(std::move(descriptor_resp));
+          desc_offset++;
         }
         service_resp.characteristics.push_back(std::move(characteristic_resp));
       }
       resp.services.push_back(std::move(service_resp));
       api::global_api_server->send_bluetooth_gatt_services(resp);
-      // Descriptors are rarely used and can be quite large so we clear them
-      // after sending them to save memory. If something actually needs them
-      // it can parse them again.
-      for (auto &characteristic : service->characteristics) {
-        characteristic->release_descriptors();
-      }
       connection->send_service_++;
     }
   }