[Bugfix] get remote characteristic by uuid returning the wrong instance.

This fixes a bug introduced when sorting the characteristic vector where the last item on in the vector was
returned but the characteristc wasn't at the end anymore.

This reverts the previous sorting of the vector after retrieval and instead sorts as the characteristics are found and also
provides a pointer to the characteristic from the retrieval callback.

Author: h2zero

src/NimBLERemoteService.cpp

@@ -25,7 +25,6 @@
 # include "NimBLELog.h"
 
 # include <climits>
-# include <algorithm>
 
 static const char* LOG_TAG = "NimBLERemoteService";
 
@@ -77,48 +76,34 @@ NimBLERemoteCharacteristic* NimBLERemoteService::getCharacteristic(const char* u
 NimBLERemoteCharacteristic* NimBLERemoteService::getCharacteristic(const NimBLEUUID& uuid) const {
     NIMBLE_LOGD(LOG_TAG, ">> getCharacteristic: uuid: %s", uuid.toString().c_str());
     NimBLERemoteCharacteristic* pChar     = nullptr;
-    size_t                      prev_size = m_vChars.size();
 
     for (const auto& it : m_vChars) {
         if (it->getUUID() == uuid) {
             pChar = it;
-            goto Done;
+            NIMBLE_LOGD(LOG_TAG, "<< getCharacteristic: found in cache");
+            return pChar;
         }
     }
 
-    if (retrieveCharacteristics(&uuid)) {
-        if (m_vChars.size() > prev_size) {
-            pChar = m_vChars.back();
-            goto Done;
-        }
-
+    if (retrieveCharacteristics(&uuid, &pChar) && pChar == nullptr) {
         // If the request was successful but 16/32 bit uuid not found
         // try again with the 128 bit uuid.
         if (uuid.bitSize() == BLE_UUID_TYPE_16 || uuid.bitSize() == BLE_UUID_TYPE_32) {
             NimBLEUUID uuid128(uuid);
             uuid128.to128();
-            if (retrieveCharacteristics(&uuid128)) {
-                if (m_vChars.size() > prev_size) {
-                    pChar = m_vChars.back();
-                }
-            }
+            retrieveCharacteristics(&uuid128, &pChar);
         } else {
             // If the request was successful but the 128 bit uuid not found
             // try again with the 16 bit uuid.
             NimBLEUUID uuid16(uuid);
             uuid16.to16();
             // if the uuid was 128 bit but not of the BLE base type this check will fail
             if (uuid16.bitSize() == BLE_UUID_TYPE_16) {
-                if (retrieveCharacteristics(&uuid16)) {
-                    if (m_vChars.size() > prev_size) {
-                        pChar = m_vChars.back();
-                    }
-                }
+                retrieveCharacteristics(&uuid16, &pChar);
             }
         }
     }
 
-Done:
     NIMBLE_LOGD(LOG_TAG, "<< Characteristic %sfound", pChar ? "" : "not ");
     return pChar;
 } // getCharacteristic
@@ -166,7 +151,14 @@ int NimBLERemoteService::characteristicDiscCB(uint16_t              conn_handle,
     }
 
     if (error->status == 0) {
-        pSvc->m_vChars.push_back(new NimBLERemoteCharacteristic(pSvc, chr));
+        // insert in handle order
+        for (auto it = pSvc->m_vChars.begin(); it != pSvc->m_vChars.end(); ++it) {
+            if ((*it)->getHandle() > chr->def_handle) {
+                pTaskData->m_pBuf = (*pSvc->m_vChars.insert(it, new NimBLERemoteCharacteristic(pSvc, chr)));
+                return 0;
+            }
+        }
+        pTaskData->m_pBuf = pSvc->m_vChars.emplace_back(new NimBLERemoteCharacteristic(pSvc, chr));
         return 0;
     }
 
@@ -180,7 +172,7 @@ int NimBLERemoteService::characteristicDiscCB(uint16_t              conn_handle,
  * This function will not return until we have all the characteristics.
  * @return True if successful.
  */
-bool NimBLERemoteService::retrieveCharacteristics(const NimBLEUUID* uuidFilter) const {
+bool NimBLERemoteService::retrieveCharacteristics(const NimBLEUUID* uuidFilter, NimBLERemoteCharacteristic** ppChar) const {
     NIMBLE_LOGD(LOG_TAG, ">> retrieveCharacteristics()");
     int            rc = 0;
     NimBLETaskData taskData(const_cast<NimBLERemoteService*>(this));
@@ -208,12 +200,9 @@ bool NimBLERemoteService::retrieveCharacteristics(const NimBLEUUID* uuidFilter)
     NimBLEUtils::taskWait(taskData, BLE_NPL_TIME_FOREVER);
     rc = taskData.m_flags;
     if (rc == 0 || rc == BLE_HS_EDONE) {
-        // sort the characteristics vector by handle to make sure the search range for descriptors is correct
-        std::sort(m_vChars.begin(),
-                  m_vChars.end(),
-                  [](const NimBLERemoteCharacteristic* a, const NimBLERemoteCharacteristic* b) {
-                      return a->getHandle() < b->getHandle();
-                  });
+        if (ppChar != nullptr) {
+            *ppChar = static_cast<NimBLERemoteCharacteristic*>(taskData.m_pBuf);
+        }
         NIMBLE_LOGD(LOG_TAG, "<< retrieveCharacteristics()");
         return true;
     }

src/NimBLERemoteService.h

@@ -53,7 +53,7 @@ class NimBLERemoteService : public NimBLEAttribute {
 
     NimBLERemoteService(NimBLEClient* pClient, const struct ble_gatt_svc* service);
     ~NimBLERemoteService();
-    bool       retrieveCharacteristics(const NimBLEUUID* uuidFilter = nullptr) const;
+    bool retrieveCharacteristics(const NimBLEUUID* uuidFilter = nullptr, NimBLERemoteCharacteristic** ppChar = nullptr) const;
     static int characteristicDiscCB(uint16_t                     conn_handle,
                                     const struct ble_gatt_error* error,
                                     const struct ble_gatt_chr*   chr,