add locks in presence detection for _device dictionary

src/PresenceDetection.cpp

@@ -45,19 +45,23 @@ char* PresenceDetection::generateCsv()
 
     _csvIndex = 0;
     long ts = millis();
-    for(auto it : _devices)
     {
-        if(ts - _timeout < it.second->timestamp)
+        std::lock_guard<std::mutex> lock(mtx);
+
+        for (auto it: _devices)
+        {
+            if (ts - _timeout < it.second->timestamp)
             {
                 buildCsv(it.second);
             }
 
             // Prevent csv buffer overflow
-        if(_csvIndex > _bufferSize - (sizeof(it.second->name) + sizeof(it.second->address) + 10))
+            if (_csvIndex > _bufferSize - (sizeof(it.second->name) + sizeof(it.second->address) + 10))
             {
                 break;
             }
         }
+    }
 
     if(_csvIndex == 0)
     {
@@ -131,8 +135,24 @@ void PresenceDetection::onResult(NimBLEAdvertisedDevice *device)
 
     long long addr = strtoll(addrArrComp, nullptr, 16);
 
+    bool found;
+    {
+        std::lock_guard<std::mutex> lock(mtx);
         auto it = _devices.find(addr);
-    if(it == _devices.end())
+        found = (it != _devices.end());
+
+        if(found)
+        {
+            it->second->timestamp = millis();
+            if(device->haveRSSI())
+            {
+                it->second->hasRssi = true;
+                it->second->rssi = device->getRSSI();
+            }
+        }
+    }
+
+    if(!found)
     {
 
         std::shared_ptr<PdDevice> pdDevice = std::make_shared<PdDevice>();
@@ -166,8 +186,11 @@ void PresenceDetection::onResult(NimBLEAdvertisedDevice *device)
 
             pdDevice->timestamp = millis();
 
+            {
+                std::lock_guard<std::mutex> lock(mtx);
                 _devices[addr] = pdDevice;
             }
+        }
         else if (device->haveManufacturerData())
         {
             std::string strManufacturerData = device->getManufacturerData();
@@ -184,19 +207,13 @@ void PresenceDetection::onResult(NimBLEAdvertisedDevice *device)
                 {
                     pdDevice->timestamp = millis();
                     strcpy(pdDevice->name, oBeacon.getProximityUUID().toString().c_str());
+                    {
+                        std::lock_guard<std::mutex> lock(mtx);
                         _devices[addr] = pdDevice;
                     }
                 }
             }
         }
-    else
-    {
-        it->second->timestamp = millis();
-        if(device->haveRSSI())
-        {
-            it->second->hasRssi = true;
-            it->second->rssi = device->getRSSI();
-        }
     }
 
 //    if(device->haveName())

src/PresenceDetection.h

@@ -4,6 +4,7 @@
 #include "BleScanner.h"
 #include "BleInterfaces.h"
 #include <memory>
+#include <mutex>
 
 struct PdDevice
 {
@@ -29,6 +30,8 @@ public:
 private:
     void buildCsv(const std::shared_ptr<PdDevice>& device);
 
+    std::mutex mtx;
+
     Preferences* _preferences;
     BleScanner::Scanner* _bleScanner;
     char* _csv = {0};