Changed iterator logic to capture header list by reference

Author: accelerated

include/cppkafka/header_list.h

@@ -306,15 +306,13 @@ bool HeaderList<HeaderType>::empty() const {
 template <typename HeaderType>
 typename HeaderList<HeaderType>::Iterator
 HeaderList<HeaderType>::begin() const {
-    return empty() ? Iterator(HeaderList<HeaderType>(), 0) :
-                     Iterator(make_non_owning(handle_.get()), 0);
+    return Iterator(*this, 0);
 }
 
 template <typename HeaderType>
 typename HeaderList<HeaderType>::Iterator
 HeaderList<HeaderType>::end() const {
-    return empty() ? Iterator(HeaderList<HeaderType>(), size()) :
-                     Iterator(make_non_owning(handle_.get()), size());
+    return Iterator(*this, size());
 }
 
 template <typename HeaderType>

include/cppkafka/header_list_iterator.h

@@ -151,10 +151,9 @@ class HeaderIterator {
     }
 
 private:
-    HeaderIterator(HeaderListType headers,
+    HeaderIterator(const HeaderListType& headers,
                    size_t index)
-    : header_list_(std::move(headers)),
-      header_(header_list_.empty() ? HeaderType() : header_list_.at(index)),
+    : header_list_(headers),
       index_(index) {
     }
 
@@ -169,7 +168,7 @@ class HeaderIterator {
                                      other.get_value().get_size()));
     }
 
-    HeaderListType header_list_;
+    const HeaderListType& header_list_;
     HeaderType header_;
     size_t index_;
 };