Added a toAqlValue in ManagedDocumentResult that should be called from outside. This figures out if we have to copy the content into the AqlValue or if we could just point to the raw data.

arangod/Aql/IndexBlock.cpp

@@ -512,10 +512,8 @@ AqlItemBlock* IndexBlock::getSome(size_t atLeast, size_t atMost) {
         }
       }
       if (_cursor->collection()->readDocument(_trx, token, *_mmdr)) {
-        uint8_t const* vpack = _mmdr->vpack(); //back();
-        // TODO use internal toAQL function
         res->setValue(_returned, static_cast<arangodb::aql::RegisterId>(curRegs),
-            AqlValue(VPackSlice(vpack)));
+            _mmdr->createAqlValue());
 
         if (_returned > 0) {
           // re-use already copied AqlValues
@@ -531,10 +529,8 @@ AqlItemBlock* IndexBlock::getSome(size_t atLeast, size_t atMost) {
     callback = [&](DocumentIdentifierToken const& token) {
       TRI_ASSERT(res.get() != nullptr);
       if (_cursor->collection()->readDocument(_trx, token, *_mmdr)) {
-        uint8_t const* vpack = _mmdr->vpack(); //back();
-        // TODO use internal toAQL function
         res->setValue(_returned, static_cast<arangodb::aql::RegisterId>(curRegs),
-            AqlValue(VPackSlice(vpack)));
+            _mmdr->createAqlValue());
 
         if (_returned > 0) {
           // re-use already copied AqlValues

arangod/VocBase/ManagedDocumentResult.cpp

@@ -22,12 +22,14 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 #include "ManagedDocumentResult.h"
+#include "Aql/AqlValue.h"
 
 #include <velocypack/Builder.h>
 #include <velocypack/Slice.h>
 #include <velocypack/velocypack-aliases.h>
 
 using namespace arangodb;
+using namespace arangodb::aql;
 
 void ManagedDocumentResult::clone(ManagedDocumentResult& cloned) const {
   cloned.reset();
@@ -100,3 +102,17 @@ void ManagedDocumentResult::addToBuilder(velocypack::Builder& builder, bool allo
     builder.add(velocypack::Slice(_vpack));
   }
 }
+
+// @brief Creates an AQLValue with the content of this ManagedDocumentResult
+// The caller is responsible to properly destroy() the
+// returned value
+AqlValue ManagedDocumentResult::createAqlValue() const {
+  TRI_ASSERT(!empty());
+  if (canUseInExternal()) {
+    // No need to copy. Underlying structure guarantees that Slices stay
+    // valid
+    return AqlValue(_vpack, AqlValueFromManagedDocument());
+  }
+  // Do copy. Otherwise the slice may go out of scope
+  return AqlValue(VPackSlice(_vpack));
+}

arangod/VocBase/ManagedDocumentResult.h

@@ -32,6 +32,10 @@ namespace velocypack {
 class Builder;
 }
 
+namespace aql {
+struct AqlValue;
+}
+
 class ManagedDocumentResult {
  public:
   ManagedDocumentResult() :
@@ -91,6 +95,11 @@ class ManagedDocumentResult {
   
   void addToBuilder(velocypack::Builder& builder, bool allowExternals) const;
 
+  // @brief Creates an AQLValue with the content of this ManagedDocumentResult
+  // The caller is responsible to properly destroy() the
+  // returned value
+  aql::AqlValue createAqlValue() const;
+
  private:
   uint64_t _length;
   TRI_voc_rid_t _lastRevisionId;