Fix leaks last blob on driver restart (indilib#1909)

libs/indidevice/basedevice.cpp

@@ -460,6 +460,15 @@ int BaseDevice::buildProp(const INDI::LilXmlElement &root, char *errmsg, bool is
         case INDI_BLOB:
         {
             INDI::PropertyBlob typedProperty {0};
+            typedProperty.setBlobDeleter([](void *&blob)
+            {
+#ifdef ENABLE_INDI_SHARED_MEMORY
+                IDSharedBlobFree(blob);
+#else
+                free(blob);
+#endif
+                blob = nullptr;
+            });
             for (const auto &element : root.getElementsByTagName("defBLOB"))
             {
                 INDI::WidgetViewBlob widget;

libs/indidevice/property/indipropertyblob.cpp

@@ -27,7 +27,16 @@ PropertyBlobPrivate::PropertyBlobPrivate(size_t count)
 { }
 
 PropertyBlobPrivate::~PropertyBlobPrivate()
-{ }
+{
+    for (auto &it: widgets)
+    {
+        auto blob = it.getBlob();
+        if (blob != nullptr && deleter != nullptr)
+        {
+            deleter(blob);
+        }
+    }
+}
 
 PropertyBlob::PropertyBlob(size_t count)
     : PropertyBasic<IBLOB>(*new PropertyBlobPrivate(count))
@@ -40,6 +49,12 @@ PropertyBlob::PropertyBlob(INDI::Property property)
 PropertyBlob::~PropertyBlob()
 { }
 
+void PropertyBlob::setBlobDeleter(const std::function<void(void *&)> &deleter)
+{
+    D_PTR(PropertyBlob);
+    d->deleter = deleter;
+}
+
 bool PropertyBlob::update(
     const int sizes[], const int blobsizes[], const char * const blobs[], const char * const formats[],
     const char * const names[], int n

libs/indidevice/property/indipropertyblob.h

@@ -31,6 +31,16 @@ class PropertyBlob: public INDI::PropertyBasic<IBLOB>
         PropertyBlob(size_t count);
         PropertyBlob(INDI::Property property);
         ~PropertyBlob();
+
+    public:
+        /**
+         * @brief Set the Blob Deleter function
+         * You can define a function to release the memory of the elements.
+         * The function will be executed when the PropertyBlob is destroyed
+         * 
+         * @param deleter function to release the memory of a given item
+         */
+        void setBlobDeleter(const std::function<void(void *&)> &deleter);
 
     public:
         bool update(

libs/indidevice/property/indipropertyblob_p.h

@@ -36,6 +36,7 @@ class PropertyBlobPrivate: public PropertyBasicPrivateTemplate<IBLOB>
         virtual ~PropertyBlobPrivate();
 
     public:
+        std::function<void(void *&)> deleter;
 
 };