attempt to fix PrimaryIndexIterator::nextBabies()

arangod/Indexes/PrimaryIndex.cpp

@@ -93,6 +93,25 @@ TRI_doc_mptr_t* PrimaryIndexIterator::next() {
   return nullptr;
 }
 
+void PrimaryIndexIterator::nextBabies(std::vector<TRI_doc_mptr_t*>& buffer, size_t limit) {
+  size_t atMost = limit;
+
+  buffer.clear();
+  
+  while (_iterator.valid() && atMost > 0) {
+    auto result = _index->lookup(_trx, _iterator.value());
+    _iterator.next();
+
+    if (result == nullptr) {
+      return;
+    }
+
+    buffer.emplace_back(result);
+    --atMost;
+  }
+}
+
+
 void PrimaryIndexIterator::reset() { _iterator.reset(); }
 
 TRI_doc_mptr_t* AllIndexIterator::next() {
@@ -102,6 +121,23 @@ TRI_doc_mptr_t* AllIndexIterator::next() {
   return _index->findSequential(_trx, _position, _total);
 };
 
+void AllIndexIterator::nextBabies(std::vector<TRI_doc_mptr_t*>& buffer, size_t limit) {
+  size_t atMost = limit;
+
+  buffer.clear();
+
+  while (atMost > 0) {
+    auto result = next();
+
+    if (result == nullptr) {
+      return;
+    }
+
+    buffer.emplace_back(result);
+    --atMost;
+  }
+}
+
 void AllIndexIterator::reset() { _position.reset(); }
 
 TRI_doc_mptr_t* AnyIndexIterator::next() {

arangod/Indexes/PrimaryIndex.h

@@ -57,6 +57,8 @@ class PrimaryIndexIterator final : public IndexIterator {
 
   TRI_doc_mptr_t* next() override;
   
+  void nextBabies(std::vector<TRI_doc_mptr_t*>&, size_t) override;
+
   void reset() override;
 
  private:
@@ -80,6 +82,8 @@ class AllIndexIterator final : public IndexIterator {
 
   TRI_doc_mptr_t* next() override;
   
+  void nextBabies(std::vector<TRI_doc_mptr_t*>&, size_t) override;
+
   void reset() override;
 
  private: