Merge lp:~zorba-coders/zorba/treeidapi into lp:zorba

[Ghislain Fourny]

Introducing tree ID API.

Introducing tree ID API.

[Zorba Build Bot (zorba-buildbot)]

Validation queue starting for merge proposal.
Log at: http://zorbatest.lambda.nu:8080/remotequeue/treeidapi-2012-02-17T15-44-01.686Z/log.html

[Zorba Build Bot (zorba-buildbot)]

Validation queue job treeidapi-2012-02-17T15-44-01.686Z is finished. The final status was:

All tests succeeded!

[Zorba Build Bot (zorba-buildbot)]

Voting does not meet specified criteria. Required: Approve > 1, Disapprove < 1. Got: 3 Pending.

[Matthias Brantner (matthias-brantner)]

It seems to me that the change you are proposing is adding a lot of overhead. Especially for the simple store, a ulong with simple arithmetic operations has been replaced with a class containing several virtual functions.

I propose the following alternative solution which we should consider:

- make the SimpleStore and XmlNode template classes
- introduce typedefs to keep the textual changes minimal
- the template parameters are the TreeId that should be used and a traits class providing the required operations for the TreeId
- in the simplestore,
  - the type of the TreeId would be ulong
  - the traits class would implement the basic operations very efficiently (e.g. + operator or < with ulongs)
- in some other store,
  - the type of the TreeId could be a uuid
  - the traits class would implement the operations on top of uuids

This way, the simplestore's code that is actually executed (i.e. there is no runtime overhead). Also, once this extension mechanism is in place, other dynamic extensions (e.g. factories) could be replaced also in order to avoid even more runtime overhead.

review: Needs Information

=== modified file 'src/store/naive/CMakeLists.txt'
--- src/store/naive/CMakeLists.txt	2011-06-22 17:30:15 +0000
+++ src/store/naive/CMakeLists.txt	2012-02-17 15:26:34 +0000
@@ -47,6 +47,7 @@
     inmemorystore.cpp
     inmemorystorec.cpp
     dataguide.cpp
+    tree_id.cpp
 )
 
 IF (NOT ZORBA_NO_FULL_TEXT)

=== modified file 'src/store/naive/atomic_items.cpp'
--- src/store/naive/atomic_items.cpp	2012-02-15 10:25:02 +0000
+++ src/store/naive/atomic_items.cpp	2012-02-17 15:26:34 +0000
@@ -40,6 +40,7 @@
 #include "node_items.h"
 #include "atomic_items.h"
 #include "ordpath.h"
+#include "tree_id.h"
 
 #include "util/ascii_util.h"
 #include "util/string_util.h"
@@ -1043,12 +1044,12 @@
 StructuralAnyUriItem::StructuralAnyUriItem(
     zstring& encoded,
     ulong collectionId,
-    ulong treeId, 
+    const TreeId_t& treeId, 
     store::StoreConsts::NodeKind nodeKind,
     const OrdPath& ordPath)
   :
   theCollectionId(collectionId),
-  theTreeId(treeId),
+  theTreeId(treeId->copy()),
   theNodeKind(nodeKind),
   theOrdPath(ordPath)
 {
@@ -1091,8 +1092,10 @@
   //
   // Decode tree id
   //
-  theTreeId = strtoul(start, &next, 10);
-
+  ulong ulid = strtoul(start, &next, 10);
+  ostringstream oss;
+  oss << std::dec << ulid;
+  theTreeId = GET_DEFAULT_TREE_ID_GENERATOR().fromString(oss.str());
   if (errno != 0 || start == next)
     throw ZORBA_EXCEPTION(zerr::ZAPI0028_INVALID_NODE_URI, ERROR_PARAMS(theValue));
 
@@ -1144,7 +1147,7 @@
 
     return 
     (other->theCollectionId == theCollectionId &&
-     other->theTreeId == theTreeId &&
+     GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
      theOrdPath.getRelativePosition(other->theOrdPath) == OrdPath::ANCESTOR);
   }
 }
@@ -1169,7 +1172,7 @@
 
     return 
     (other->theCollectionId == theCollectionId &&
-     other->theTreeId == theTreeId &&
+     GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
      other->theNodeKind != store::StoreConsts::attributeNode &&
      theNodeKind != store::StoreConsts::attributeNode &&
      theOrdPath.getRelativePosition2(other->theOrdPath) == OrdPath::FOLLOWING_SIBLING);
@@ -1196,7 +1199,7 @@
 
     return 
     (other->theCollectionId == theCollectionId &&
-     other->theTreeId == theTreeId &&
+     GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
      theOrdPath.getRelativePosition(other->theOrdPath) == OrdPath::FOLLOWING);
   }
 }
@@ -1220,7 +1223,7 @@
     StructuralAnyUriItem* other = static_cast<StructuralAnyUriItem*>(aOther.getp());
     return 
     (other->theCollectionId == theCollectionId &&
-     other->theTreeId == theTreeId &&
+     GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
      other->theNodeKind != store::StoreConsts::attributeNode &&
      theOrdPath.getRelativePosition(other->theOrdPath) == OrdPath::DESCENDANT);
   }
@@ -1245,7 +1248,7 @@
     StructuralAnyUriItem* other = static_cast<StructuralAnyUriItem*>(aOther.getp());
     return 
     (other->theCollectionId == theCollectionId &&
-     other->theTreeId == theTreeId &&
+     GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
      theOrdPath.getRelativePosition(other->theOrdPath) == OrdPath::DESCENDANT);
   }
 }
@@ -1269,7 +1272,7 @@
     StructuralAnyUriItem* other = static_cast<StructuralAnyUriItem*>(aOther.getp());
     return 
     (other->theCollectionId == theCollectionId &&
-     other->theTreeId == theTreeId &&
+     GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
      other->theNodeKind != store::StoreConsts::attributeNode &&
      theNodeKind != store::StoreConsts::attributeNode &&
      theOrdPath.getRelativePosition2(other->theOrdPath) == OrdPath::PRECEDING_SIBLING);
@@ -1295,7 +1298,7 @@
     StructuralAnyUriItem* other = static_cast<StructuralAnyUriItem*>(aOther.getp());
     return 
     (other->theCollectionId == theCollectionId &&
-     other->theTreeId == theTreeId &&
+     GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
      theOrdPath.getRelativePosition(other->theOrdPath) == OrdPath::PRECEDING);
   }
 }
@@ -1319,7 +1322,7 @@
     StructuralAnyUriItem* other = static_cast<StructuralAnyUriItem*>(aOther.getp());
     return 
     (other->theCollectionId == theCollectionId &&
-     other->theTreeId == theTreeId &&
+     GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
      other->theNodeKind != store::StoreConsts::attributeNode &&
      theOrdPath.getRelativePosition2(other->theOrdPath) == OrdPath::CHILD);
   }
@@ -1344,7 +1347,7 @@
     StructuralAnyUriItem* other = static_cast<StructuralAnyUriItem*>(aOther.getp());
     return 
     (other->theCollectionId == theCollectionId &&
-     other->theTreeId == theTreeId &&
+     GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
      other->theNodeKind == store::StoreConsts::attributeNode &&
      theOrdPath.getRelativePosition2(other->theOrdPath) == OrdPath::CHILD);
   }
@@ -1369,7 +1372,7 @@
     StructuralAnyUriItem* other = static_cast<StructuralAnyUriItem*>(aOther.getp());
     return 
     (other->theCollectionId == theCollectionId &&
-     other->theTreeId == theTreeId &&
+     GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
      theOrdPath.getRelativePosition2(other->theOrdPath) == OrdPath::PARENT);
   }
 }
@@ -1391,8 +1394,11 @@
     StructuralAnyUriItem* other = static_cast<StructuralAnyUriItem*>(aOther.getp());
     return
     (theCollectionId > other->theCollectionId ||
-    (theCollectionId == other->theCollectionId && theTreeId > other->theTreeId) ||
-    (theCollectionId == other->theCollectionId && other->theTreeId == theTreeId && theOrdPath > other->theOrdPath));
+    (theCollectionId == other->theCollectionId &&
+        GET_DEFAULT_TREE_ID_GENERATOR().isBefore(other->theTreeId, theTreeId)) ||
+    (theCollectionId == other->theCollectionId &&
+        GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
+        theOrdPath > other->theOrdPath));
   }
 }
 
@@ -1413,8 +1419,11 @@
     StructuralAnyUriItem* other = static_cast<StructuralAnyUriItem*>(aOther.getp());
     return
     (theCollectionId < other->theCollectionId ||
-    (theCollectionId == other->theCollectionId && theTreeId < other->theTreeId) ||
-    (theCollectionId == other->theCollectionId && other->theTreeId == theTreeId && theOrdPath < other->theOrdPath));
+    (theCollectionId == other->theCollectionId &&
+        GET_DEFAULT_TREE_ID_GENERATOR().isBefore(theTreeId, other->theTreeId)) ||
+    (theCollectionId == other->theCollectionId &&
+        GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
+        theOrdPath < other->theOrdPath));
   }
 }
 
@@ -1479,7 +1488,7 @@
     StructuralAnyUriItem* other = static_cast<StructuralAnyUriItem*>(aOther.getp());
 
     if (other->theCollectionId == theCollectionId &&
-        other->theTreeId == theTreeId &&
+        GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId) &&
         other->theNodeKind != store::StoreConsts::attributeNode &&
         theNodeKind != store::StoreConsts::attributeNode)
     {
@@ -1512,7 +1521,7 @@
   {
     StructuralAnyUriItem* other = static_cast<StructuralAnyUriItem*>(aOther.getp());
     return (theCollectionId == other->theCollectionId &&
-            theTreeId == other->theTreeId);
+            GET_DEFAULT_TREE_ID_GENERATOR().equals(other->theTreeId, theTreeId));
   }
 }
 

=== modified file 'src/store/naive/atomic_items.h'
--- src/store/naive/atomic_items.h	2012-01-26 19:56:14 +0000
+++ src/store/naive/atomic_items.h	2012-02-17 15:26:34 +0000
@@ -31,6 +31,7 @@
 #include "store/api/xs_type_codes.h"
 #include "store/naive/store_defs.h"
 #include "store/naive/shared_types.h"
+#include "tree_id.h"
 
 #ifndef ZORBA_NO_FULL_TEXT
 #include "store/naive/naive_ft_token_iterator.h"
@@ -615,7 +616,7 @@
 
 protected:
   ulong                        theCollectionId;
-  ulong                        theTreeId;
+  TreeId_t                     theTreeId;
   store::StoreConsts::NodeKind theNodeKind;
   OrdPath                      theOrdPath;
 
@@ -630,7 +631,7 @@
   StructuralAnyUriItem(
       zstring& value,
       ulong collectionId,
-      ulong treeId,
+      const TreeId_t& treeId,
       store::StoreConsts::NodeKind nodeKind,
       const OrdPath& ordPath);
 

=== modified file 'src/store/naive/loader_dtd.cpp'
--- src/store/naive/loader_dtd.cpp	2012-02-15 10:25:02 +0000
+++ src/store/naive/loader_dtd.cpp	2012-02-17 15:26:34 +0000
@@ -124,7 +124,7 @@
   if (docUri.empty())
   {
     std::ostringstream uristream;
-    uristream << "zorba://internalDocumentURI-" << theTree->getId();
+    uristream << "zorba://internalDocumentURI-" << theTree->getId()->toString();
     theDocUri = uristream.str();
   }
   else
@@ -566,7 +566,7 @@
   if (docUri.empty())
   {
     std::ostringstream uristream;
-    uristream << "zorba://internalDocumentURI-" << theTree->getId();
+    uristream << "zorba://internalDocumentURI-" << theTree->getId()->toString();
 
     theDocUri = uristream.str();
   }

=== modified file 'src/store/naive/loader_fast.cpp'
--- src/store/naive/loader_fast.cpp	2012-02-15 10:25:02 +0000
+++ src/store/naive/loader_fast.cpp	2012-02-17 15:26:34 +0000
@@ -260,7 +260,7 @@
   if (docUri.empty())
   {
     std::ostringstream uristream;
-    uristream << "zorba://internalDocumentURI-" << theTree->getId();
+    uristream << "zorba://internalDocumentURI-" << theTree->getId()->toString();
 
     theDocUri = uristream.str();
   }

=== modified file 'src/store/naive/node_items.cpp'
--- src/store/naive/node_items.cpp	2012-02-15 10:25:02 +0000
+++ src/store/naive/node_items.cpp	2012-02-17 15:26:34 +0000
@@ -81,7 +81,7 @@
 }
 
 
-XmlTree::XmlTree(XmlNode* root, ulong id)
+XmlTree::XmlTree(XmlNode* root, TreeId_t id)
   :
   theRefCount(0),
   theId(id),
@@ -1548,7 +1548,7 @@
   theDocUri(docUri)
 {
   NODE_TRACE1("{\nConstructing doc node " << this << " tree = "
-              << getTree()->getId() << ":" << getTree()
+              << getTree()->getId()->toString() << ":" << getTree()
               << " doc uri = " << docUri);
 }
 
@@ -1900,7 +1900,7 @@
 
   NODE_TRACE1("Constructed element node " << this << " parent = "
               << std::hex << (parent ? (ulong)parent : 0) << " pos = " << pos
-              << " tree = " << getTree()->getId() << ":" << getTree()
+              << " tree = " << getTree()->getId()->toString() << ":" << getTree()
               << " ordpath = " << theOrdPath.show()
               << " name = " << theName->getStringValue()
               << " type = " << getType()->getStringValue());
@@ -3332,7 +3332,7 @@
 
   NODE_TRACE1("Constructed attribute node " << this << " parent = "
               << std::hex << (parent ? (ulong)parent : 0) << " pos = " << pos
-              << " tree = " << getTree()->getId() << ":" << getTree()
+              << " tree = " << getTree()->getId()->toString() << ":" << getTree()
               << " ordpath = " << theOrdPath.show()
               << " name = " << theName->getStringValue()
               << " value = " << getStringValue());
@@ -3714,7 +3714,7 @@
 #else
   NODE_TRACE1("Constructed text node " << this << " parent = "
               << std::hex << (parent ? (ulong)parent : 0) << " pos = " << pos
-              << " tree = " << getTree()->getId() << ":" << getTree()
+              << " tree = " << getTree()->getId()->toString() << ":" << getTree()
               << " content = " << getText());
 #endif
 }
@@ -4396,7 +4396,7 @@
 
   NODE_TRACE1("Constructed pi node " << this << " parent = "
               << std::hex << (parent ? (ulong)parent : 0) << " pos = " << pos
-              << " tree = " << getTree()->getId() << ":" << getTree()
+              << " tree = " << getTree()->getId()->toString() << ":" << getTree()
               << " ordpath = " << theOrdPath.show() << " target = " << theTarget);
 }
 
@@ -4521,7 +4521,7 @@
 
   NODE_TRACE1("Constructed comment node " << this << " parent = "
               << std::hex << (parent ? (ulong)parent : 0) << " pos = " << pos
-              << " tree = " << getTree()->getId() << ":" << getTree()
+              << " tree = " << getTree()->getId()->toString() << ":" << getTree()
               << " ordpath = " << theOrdPath.show() << " content = "
               << theContent);
 }

=== modified file 'src/store/naive/node_items.h'
--- src/store/naive/node_items.h	2012-01-26 19:56:14 +0000
+++ src/store/naive/node_items.h	2012-02-17 15:26:34 +0000
@@ -29,6 +29,8 @@
 #include "store/naive/item_vector.h"
 #include "store/naive/ordpath.h"
 #include "store/naive/nsbindings.h" // TODO remove by introducing explicit destructors
+#include "tree_id.h"
+#include "simple_store.h"
 
 // Note: whether the EMBEDED_TYPE is defined or not is done in store_defs.h
 #ifndef EMBEDED_TYPE
@@ -177,7 +179,7 @@
   mutable long              theRefCount;
   SYNC_CODE(mutable RCLock  theRCLock;)
 
-  ulong                     theId;
+  TreeId_t                  theId;
   ulong                     thePos;
 
   SimpleCollection        * theCollection;
@@ -200,7 +202,7 @@
 #endif
 
 protected:
-  XmlTree(XmlNode* root, ulong id);
+  XmlTree(XmlNode* root, TreeId_t id);
 
 public:
   XmlTree();
@@ -215,9 +217,9 @@
 
   SYNC_CODE(RCLock* getRCLock() const { return &theRCLock; })
 
-  void setId(ulong id) { theId = id; }
+  void setId(TreeId_t id) { theId = id; }
 
-  ulong getId() const { return theId; }
+  const TreeId_t& getId() const { return theId; }
 
   ulong getCollectionId() const;
 
@@ -512,7 +514,7 @@
 
   XmlTree* getTree() const { return (XmlTree*)theUnion.treeRCPtr; }
 
-  ulong getTreeId() const { return getTree()->getId(); }
+  const TreeId_t& getTreeId() const { return getTree()->getId(); }
 
   XmlNode* getRoot() const { return getTree()->getRoot(); }
 
@@ -1618,13 +1620,13 @@
   {
     if (col1 == 0)
     {
-      ulong tree1 = this->getTreeId();
-      ulong tree2 = other->getTreeId();
+      const TreeId_t& tree1 = this->getTreeId();
+      const TreeId_t& tree2 = other->getTreeId();
 
-      if (tree1 < tree2)
+      if (GET_DEFAULT_TREE_ID_GENERATOR().isBefore(tree1, tree2))
         return -1;
 
-      if (tree1 == tree2)
+      if (GET_DEFAULT_TREE_ID_GENERATOR().equals(tree1, tree2))
         return compareInSameTree(this, other);
     }
     else

=== modified file 'src/store/naive/simple_collection.cpp'
--- src/store/naive/simple_collection.cpp	2012-02-15 10:25:02 +0000
+++ src/store/naive/simple_collection.cpp	2012-02-17 15:26:34 +0000
@@ -41,11 +41,11 @@
   : 
   theName(aName),
   theIsDynamic(aDynamicCollection),
-  theTreeCounter(1),
   theAnnotations(aAnnotations),
   theNodeType(aNodeType)
 {
   theId = GET_STORE().createCollectionId();
+  theTreeIdGenerator = GET_STORE().getTreeIdGeneratorFactory().createTreeGenerator();
 }
 
 /*******************************************************************************
@@ -54,9 +54,9 @@
 SimpleCollection::SimpleCollection()
   : 
   theIsDynamic(false),
-  theTreeCounter(1),
   theNodeType(NULL)
 {
+  theTreeIdGenerator = GET_STORE().getTreeIdGeneratorFactory().createTreeGenerator();
 }
 
 /*******************************************************************************
@@ -379,7 +379,9 @@
   std::size_t lPosition = to_xs_unsignedInt(position);
 
   if (lPosition < theXmlTrees.size() &&
-      BASE_NODE(theXmlTrees[lPosition])->getTreeId() == n->getTreeId())
+      GET_DEFAULT_TREE_ID_GENERATOR().equals(
+          BASE_NODE(theXmlTrees[lPosition])->getTreeId(),
+          n->getTreeId()))
   {
     return true;
   }
@@ -491,6 +493,13 @@
   activeICNames->close();
 }
 
+/*******************************************************************************
+
+********************************************************************************/
+TreeId_t SimpleCollection::createTreeId()
+{
+  return theTreeIdGenerator->create();
+}
 
 /*******************************************************************************
 

=== modified file 'src/store/naive/simple_collection.h'
--- src/store/naive/simple_collection.h	2012-01-15 09:18:22 +0000
+++ src/store/naive/simple_collection.h	2012-02-17 15:26:34 +0000
@@ -20,6 +20,7 @@
 
 #include "store/api/iterator.h"
 #include "store/api/collection.h"
+#include "tree_id.h"
 
 #include "zorbautils/latch.h"
 #include "zorbautils/checked_vector.h"
@@ -68,7 +69,7 @@
   checked_vector<store::Item_t>   theXmlTrees;
   bool                            theIsDynamic;
 
-  ulong                           theTreeCounter;
+  TreeIdGenerator*                theTreeIdGenerator;
 
   const std::vector<store::Annotation_t> theAnnotations;
   store::Item_t                   theNodeType;
@@ -100,7 +101,7 @@
   void getAnnotations(std::vector<store::Annotation_t>& annotations) const;
 
   // virtual to allow extension by subclasses
-  virtual ulong createTreeId() { return theTreeCounter++; }
+  virtual TreeId_t createTreeId();
 
   store::Iterator_t getIterator();
 

=== modified file 'src/store/naive/simple_item_factory.cpp'
--- src/store/naive/simple_item_factory.cpp	2012-02-15 10:25:02 +0000
+++ src/store/naive/simple_item_factory.cpp	2012-02-17 15:26:34 +0000
@@ -120,7 +120,7 @@
 bool BasicItemFactory::createStructuralAnyURI(
     store::Item_t& result,
     ulong collectionId,
-    ulong treeId,
+    const TreeId_t& treeId,
     store::StoreConsts::NodeKind nodeKind,
     const OrdPath& ordPath)
 {
@@ -128,7 +128,7 @@
   std::ostringstream stream;
   stream   << "zorba:"
            << collectionId << "."
-           << treeId << "."
+           << treeId->toString() << "."
            << static_cast<int>(nodeKind) << "."
            << ordPath.serialize();
   zstring uri = stream.str();

=== modified file 'src/store/naive/simple_item_factory.h'
--- src/store/naive/simple_item_factory.h	2011-12-21 14:40:33 +0000
+++ src/store/naive/simple_item_factory.h	2012-02-17 15:26:34 +0000
@@ -91,7 +91,7 @@
   bool createStructuralAnyURI(
       store::Item_t& result,
       ulong collectionId,
-      ulong treeId,
+      const TreeId_t& treeId,
       store::StoreConsts::NodeKind nodeKind,
       const OrdPath& ordPath);
 

=== modified file 'src/store/naive/simple_store.cpp'
--- src/store/naive/simple_store.cpp	2012-02-15 10:25:02 +0000
+++ src/store/naive/simple_store.cpp	2012-02-17 15:26:34 +0000
@@ -56,6 +56,7 @@
 #include "name_iterator.h"
 #include "document_name_iterator.h"
 #include "pul_primitive_factory.h"
+#include "tree_id.h"
 
 #include "util/cxx_util.h"
 #include "util/uuid/uuid.h"
@@ -102,6 +103,7 @@
   theIteratorFactory(NULL),
   theNodeFactory(NULL),
   thePULFactory(NULL),
+  theTreeIdGeneratorFactory(NULL),
   theDocuments(CollectionSet::DEFAULT_COLLECTION_MAP_SIZE, true),
   theCollections(0),
   theIndices(0, NULL, CollectionSet::DEFAULT_COLLECTION_MAP_SIZE, true),
@@ -169,6 +171,8 @@
     theNodeFactory = createNodeFactory();
 
     thePULFactory = createPULPrimitiveFactory();
+    
+    theTreeIdGeneratorFactory = createTreeIdGeneratorFactory();
 
     theTraceLevel = store::Properties::instance()->storeTraceLevel();
 
@@ -400,6 +404,25 @@
 /*******************************************************************************
 
 *******************************************************************************/
+TreeIdGeneratorFactory*
+SimpleStore::createTreeIdGeneratorFactory() const
+{
+  return new ZorbaTreeIdGeneratorFactory();
+}
+
+
+/*******************************************************************************
+
+*******************************************************************************/
+void
+SimpleStore::destroyTreeIdGeneratorFactory(TreeIdGeneratorFactory* g) const
+{
+  delete g;
+}
+
+/*******************************************************************************
+
+*******************************************************************************/
 CollectionSet* SimpleStore::createCollectionSet() const
 {
   return new CollectionSet();
@@ -473,10 +496,10 @@
 /*******************************************************************************
   create a tree id for a new tree that does not belong to any collection.
 ********************************************************************************/
-ulong SimpleStore::createTreeId()
+TreeId_t SimpleStore::createTreeId()
 {
   SYNC_CODE(AutoMutex lock(&theTreeCounterMutex);)
-  return theTreeCounter++;
+  return getTreeIdGeneratorFactory().getDefaultTreeIdGenerator().create();
 }
 
 

=== modified file 'src/store/naive/simple_store.h'
--- src/store/naive/simple_store.h	2012-01-10 10:52:15 +0000
+++ src/store/naive/simple_store.h	2012-02-17 15:26:34 +0000
@@ -19,6 +19,7 @@
 #include "store/naive/shared_types.h"
 #include "store/naive/store_defs.h"
 #include "store/naive/hashmap_nodep.h"
+#include "tree_id.h"
 
 #if (defined (WIN32) || defined (WINCE))
 #include "store/naive/node_items.h"
@@ -48,6 +49,8 @@
   class ValueIndexSpecification;
 }
 
+class TreeIdGeneratorFactory;
+
 namespace simplestore
 {
 
@@ -125,6 +128,11 @@
   theNodeToReferencesMap:
   -----------------------
   A hashmap that maps nodes into their references
+  
+  theTreeIdGeneratorFactory:
+  --------------------------
+  An factory of ID generators (each collection can have its own in
+  addition to the default one).
 
 ********************************************************************************/
 class SimpleStore : public store::Store
@@ -173,7 +181,8 @@
   store::IteratorFactory      * theIteratorFactory;
   NodeFactory                 * theNodeFactory;
   PULPrimitiveFactory         * thePULFactory;
-
+  TreeIdGeneratorFactory      * theTreeIdGeneratorFactory;
+  
   DocumentSet                   theDocuments;
   CollectionSet*                theCollections;
   IndexSet                      theIndices;
@@ -203,6 +212,9 @@
 
   PULPrimitiveFactory& getPULFactory() const { return *thePULFactory; }
 
+  TreeIdGeneratorFactory& getTreeIdGeneratorFactory() const
+      { return *theTreeIdGeneratorFactory; }
+
   StringPool& getNamespacePool() const { return *theNamespacePool; }
 
   QNamePool& getQNamePool() const { return *theQNamePool; }
@@ -217,7 +229,7 @@
 
   ulong createCollectionId();
 
-  ulong createTreeId();
+  TreeId_t createTreeId();
 
   store::Collection_t createCollection(
       const store::Item_t& aName,
@@ -414,6 +426,10 @@
   virtual PULPrimitiveFactory* createPULPrimitiveFactory() const;
 
   virtual void destroyPULPrimitiveFactory(PULPrimitiveFactory*) const;
+  
+  virtual TreeIdGeneratorFactory* createTreeIdGeneratorFactory() const;
+
+  virtual void destroyTreeIdGeneratorFactory(TreeIdGeneratorFactory*) const;
 
   virtual CollectionSet* createCollectionSet() const;
 

=== modified file 'src/store/naive/store_defs.h'
--- src/store/naive/store_defs.h	2012-01-10 13:54:05 +0000
+++ src/store/naive/store_defs.h	2012-02-17 15:26:34 +0000
@@ -38,6 +38,9 @@
 
 #define GET_PUL_FACTORY() \
   (GET_STORE().getPULFactory())
+  
+#define GET_DEFAULT_TREE_ID_GENERATOR() \
+  (GET_STORE().getTreeIdGeneratorFactory().getDefaultTreeIdGenerator())
 
 
 #define BASE_NODE(item) (reinterpret_cast<XmlNode*>((item).getp()))

=== added file 'src/store/naive/tree_id.cpp'
--- src/store/naive/tree_id.cpp	1970-01-01 00:00:00 +0000
+++ src/store/naive/tree_id.cpp	2012-02-17 15:26:34 +0000
@@ -0,0 +1,81 @@
+/*
+ * Copyright 2006-2008 The FLWOR Foundation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "tree_id.h"
+#include <iostream>
+#include <sstream>
+
+namespace zorba {
+  
+ZorbaTreeId::ZorbaTreeId(ulong id)
+: theId(id)
+{};
+
+zstring ZorbaTreeId::toString()
+{
+  std::ostringstream oss;
+  oss << std::dec << theId;
+  return oss.str();
+}
+
+TreeId* ZorbaTreeId::copy()
+{
+  return new ZorbaTreeId(theId);
+}
+
+TreeId_t ZorbaTreeIdGenerator::create() {
+  TreeId_t lStoreRes(new ZorbaTreeId(theNextId));
+  ++theNextId;
+  return lStoreRes;
+}
+
+bool ZorbaTreeIdGenerator::equals(const TreeId_t& anId,
+                                  const TreeId_t& anotherId) const
+{
+  const ZorbaTreeId* lId1 = dynamic_cast<ZorbaTreeId*>(anId.get());
+  const ZorbaTreeId* lId2 = dynamic_cast<ZorbaTreeId*>(anotherId.get());
+  return lId1->theId == lId2->theId;
+}
+
+bool ZorbaTreeIdGenerator::isBefore(const TreeId_t& anId,
+                                    const TreeId_t& anotherId) const
+{
+  const ZorbaTreeId* lId1 = dynamic_cast<ZorbaTreeId*>(anId.get());
+  const ZorbaTreeId* lId2 = dynamic_cast<ZorbaTreeId*>(anotherId.get());
+  return lId1->theId < lId2->theId;
+}
+
+TreeId_t ZorbaTreeIdGenerator::fromString(const zstring& s) const
+{
+  std::istringstream iss(s.str());
+  ulong lId;
+  iss >> std::dec >> lId;
+  TreeId_t lRes(new ZorbaTreeId(lId));
+  return lRes;
+}
+
+TreeIdGenerator* ZorbaTreeIdGeneratorFactory::createTreeGenerator()
+{
+  return new ZorbaTreeIdGenerator();
+}
+
+TreeIdGenerator& ZorbaTreeIdGeneratorFactory::getDefaultTreeIdGenerator()
+{
+  static ZorbaTreeIdGenerator lSingleton;
+  return lSingleton;
+}
+
+}
\ No newline at end of file

=== added file 'src/store/naive/tree_id.h'
--- src/store/naive/tree_id.h	1970-01-01 00:00:00 +0000
+++ src/store/naive/tree_id.h	2012-02-17 15:26:34 +0000
@@ -0,0 +1,110 @@
+/*
+ * Copyright 2006-2008 The FLWOR Foundation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef ZORBA_TREE_ID_H
+#define ZORBA_TREE_ID_H
+
+#include "store/naive/shared_types.h"
+#include "zorbautils/hashmap_itemh.h"
+
+namespace zorba {
+
+/*
+This class is an abstract class for tree IDs.
+You can convert an ID to a string, or copy it to another instance.
+*/
+
+class TreeId {
+public:
+  virtual ~TreeId() {}
+public:
+  virtual zstring toString() = 0;
+  // Caller gets pointer ownership.
+  virtual TreeId* copy() = 0;
+};
+
+/*
+The type alias used everywhere in the program.
+Only assign IDs with = if lvalue is taking over ownership.
+Otherwise, copy.
+*/
+typedef std::auto_ptr<TreeId> TreeId_t;
+
+/*
+This class is an abstract class for tree ID generation. It provides
+a creation method, two comparison methods (= and <) as well as a way
+to parse a string back to an ID.
+*/
+class TreeIdGenerator {
+public:
+  virtual ~TreeIdGenerator() {}
+
+  virtual TreeId_t create() = 0;
+  virtual bool equals(const TreeId_t& id1, const TreeId_t& id2) const = 0;
+  virtual bool isBefore(const TreeId_t& id1, const TreeId_t& id2) const = 0;
+  virtual TreeId_t fromString(const zstring&) const = 0;
+};
+
+/*
+This class allows generation of independent tree ID generators (each of
+them might have its own counter).
+*/
+class TreeIdGeneratorFactory {
+public:
+  virtual ~TreeIdGeneratorFactory() {}
+  
+  virtual TreeIdGenerator* createTreeGenerator() = 0;
+  virtual TreeIdGenerator& getDefaultTreeIdGenerator() = 0;
+};
+
+/*
+Zorba's implementation of tree IDs, using an unsigned long.
+*/
+class ZorbaTreeId : public TreeId {
+friend class ZorbaTreeIdGenerator;
+private:
+  ulong theId;
+  ZorbaTreeId(ulong idKey);
+public:
+  zstring toString();  
+  virtual TreeId* copy();
+};
+
+/*
+Zorba's implementation of the tree ID generator.
+*/
+class ZorbaTreeIdGenerator : public TreeIdGenerator {
+private:
+  ulong theNextId;
+public:
+  ZorbaTreeIdGenerator() : theNextId(1) {}
+  virtual TreeId_t create();
+  virtual bool equals(const TreeId_t& id1, const TreeId_t& id2) const;
+  virtual bool isBefore(const TreeId_t& id1, const TreeId_t& id2) const;
+  virtual TreeId_t fromString(const zstring&) const;
+};
+
+/*
+Zorba's implementation of the tree ID generator factory.
+*/
+class ZorbaTreeIdGeneratorFactory : public TreeIdGeneratorFactory {
+public:
+  virtual TreeIdGenerator* createTreeGenerator();
+  virtual TreeIdGenerator& getDefaultTreeIdGenerator();
+};
+
+}
+
+#endif /* ZORBA_TREE_ID_H */