[BREAKING] - Refactor NimBLEScan

* General code cleanup
* `NimBLEScan::start` will no longer clear cache or results if scanning is already in progress.
* `NimBLEScan::clearResults` will now reset the vector capacity to 0.
* `NimBLEScan::stop` will no longer call the `onScanEnd` callback as the caller should know its been stopped when this is called.
* `NimBLEScan::clearDuplicateCache` has been removed as it was problematic and only for the esp32. Stop and start the scanner for the same effect.
* `NimBLEScan::start` takes a new bool parameter `restart`, default `true`, that will restart an already in progress scan and clear the duplicate filter so all devices will be discovered again.
* Scan response data that is received without advertisement first will now create the device and send a callback.
* Added new method: `NimBLEAdvertisedDevice::isScannable()` that returns true if the device is scannable.
* Added default callbacks for `NimBLEScanCallbacks`
* `NimBLEScanCallbacks` function signatures updated:
* - `onDiscovered` now takes a `const NimBLEAdvertisedDevice*`
* - `onResult` now takes a `const NimBLEAdvertisedDevice*`
* - `onScanEnd` now takes a `const NimBLEScanResults&` and `int reason`
* Added new erase overload: `NimBLEScan::erase(const NimBLEAdvertisedDevice* device)`
* `NimBLEScanResults::getDevice` methods now return `const NimBLEAdvertisedDevice*`
* `NimBLEScanResults` iterators are now `const_iterator`

Author: h2zero

examples/Advanced/NimBLE_Client/main/main.cpp

@@ -11,7 +11,7 @@
 
 extern "C" {void app_main(void);}
 
-static NimBLEAdvertisedDevice* advDevice;
+static const NimBLEAdvertisedDevice* advDevice;
 
 static bool doConnect = false;
 static uint32_t scanTime = 0; /** scan time in milliseconds, 0 = scan forever */
@@ -67,7 +67,7 @@ class ClientCallbacks : public NimBLEClientCallbacks {
 
 /** Define a class to handle the callbacks when advertisments are received */
 class scanCallbacks: public NimBLEScanCallbacks {
-    void onResult(NimBLEAdvertisedDevice* advertisedDevice) {
+    void onResult(const NimBLEAdvertisedDevice* advertisedDevice) {
         printf("Advertised Device found: %s\n", advertisedDevice->toString().c_str());
         if(advertisedDevice->isAdvertisingService(NimBLEUUID("DEAD")))
         {
@@ -82,8 +82,8 @@ class scanCallbacks: public NimBLEScanCallbacks {
     }
 
     /** Callback to process the results of the completed scan or restart it */
-    void onScanEnd(NimBLEScanResults results) {
-        printf("Scan Ended\n");
+    void onScanEnd(const NimBLEScanResults& results, int reason) {
+        printf("Scan Ended, reason: %d, device count: %d\n", reason, results.getCount());
     }
 };
 

examples/NimBLE_Async_Client/main/main.cpp

@@ -25,7 +25,7 @@ class ClientCallbacks : public NimBLEClientCallbacks {
 } clientCB;
 
 class scanCallbacks : public NimBLEScanCallbacks {
-    void onResult(NimBLEAdvertisedDevice* advertisedDevice) {
+    void onResult(const NimBLEAdvertisedDevice* advertisedDevice) {
         printf("Advertised Device found: %s\n", advertisedDevice->toString().c_str());
         if (advertisedDevice->haveName() && advertisedDevice->getName() == "NimBLE-Server") {
             printf("Found Our Device\n");

examples/basic/BLE_client/main/main.cpp

@@ -24,7 +24,7 @@ static bool doConnect = false;
 static bool connected = false;
 static bool doScan = false;
 static BLERemoteCharacteristic* pRemoteCharacteristic;
-static BLEAdvertisedDevice* myDevice;
+static const BLEAdvertisedDevice* myDevice;
 
 static void notifyCallback(
   BLERemoteCharacteristic* pBLERemoteCharacteristic,
@@ -137,7 +137,7 @@ class MyAdvertisedDeviceCallbacks: public BLEAdvertisedDeviceCallbacks {
 
 /*** Only a reference to the advertised device is passed now
   void onResult(BLEAdvertisedDevice advertisedDevice) { **/
-  void onResult(BLEAdvertisedDevice* advertisedDevice) {
+  void onResult(const BLEAdvertisedDevice* advertisedDevice) {
     printf("BLE Advertised Device found: %s\n", advertisedDevice->toString().c_str());
 
     // We have found a device, let us now see if it contains the service we are looking for.

examples/basic/BLE_scan/main/main.cpp

@@ -21,7 +21,7 @@ int scanTime = 5 * 1000; // In milliseconds, 0 = scan forever
 BLEScan* pBLEScan;
 
 class MyAdvertisedDeviceCallbacks: public BLEAdvertisedDeviceCallbacks {
-    void onResult(BLEAdvertisedDevice* advertisedDevice) {
+    void onResult(const BLEAdvertisedDevice* advertisedDevice) {
       printf("Advertised Device: %s \n", advertisedDevice->toString().c_str());
     }
 };
@@ -35,7 +35,7 @@ void scanTask (void * parameter){
         pBLEScan->clearResults();   // delete results fromBLEScan buffer to release memory
         vTaskDelay(2000/portTICK_PERIOD_MS); // Delay a second between loops.
     }
-    
+
     vTaskDelete(NULL);
 }
 

src/NimBLEAdvertisedDevice.cpp

@@ -757,6 +757,14 @@ bool NimBLEAdvertisedDevice::isConnectable() const {
     return (m_advType & BLE_HCI_ADV_CONN_MASK) || (m_advType & BLE_HCI_ADV_DIRECT_MASK);
 } // isConnectable
 
+/**
+ * @brief Check if this device is advertising as scannable.
+ * @return True if the device is scannable.
+ */
+bool NimBLEAdvertisedDevice::isScannable() const {
+    return isLegacyAdvertisement() && (m_advType == BLE_HCI_ADV_TYPE_ADV_IND || m_advType == BLE_HCI_ADV_TYPE_ADV_SCAN_IND);
+} // isScannable
+
 /**
  * @brief Check if this advertisement is a legacy or extended type
  * @return True if legacy (Bluetooth 4.x), false if extended (bluetooth 5.x).

src/NimBLEAdvertisedDevice.h

@@ -82,6 +82,7 @@ class NimBLEAdvertisedDevice {
     bool                 haveType(uint16_t type) const;
     std::string          toString() const;
     bool                 isConnectable() const;
+    bool                 isScannable() const;
     bool                 isLegacyAdvertisement() const;
 # if CONFIG_BT_NIMBLE_EXT_ADV
     uint8_t  getSetId() const;

src/NimBLEDevice.cpp

@@ -723,15 +723,7 @@ void NimBLEDevice::onReset(int reason) {
 
     m_synced = false;
 
-    NIMBLE_LOGE(LOG_TAG, "Resetting state; reason=%d, %s", reason, NimBLEUtils::returnCodeToString(reason));
-
-# if defined(CONFIG_BT_NIMBLE_ROLE_OBSERVER)
-    if (m_initialized) {
-        if (m_pScan != nullptr) {
-            m_pScan->onHostReset();
-        }
-    }
-# endif
+    NIMBLE_LOGE(LOG_TAG, "Host reset; reason=%d, %s", reason, NimBLEUtils::returnCodeToString(reason));
 } // onReset
 
 /**