initial check-in

1 files changed, 2283 insertions, 0 deletions

diff --git a/cpp/src/FreezeScript/TransformDescriptors.cpp b/cpp/src/FreezeScript/TransformDescriptors.cpp
new file mode 100644
index 00000000000..8416887975a
--- /dev/null
+++ b/cpp/src/FreezeScript/TransformDescriptors.cpp
@@ -0,0 +1,2283 @@
+// **********************************************************************
+//
+// Copyright (c) 2004
+// ZeroC, Inc.
+// Billerica, MA, USA
+//
+// All Rights Reserved.
+//
+// Ice is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License version 2 as published by
+// the Free Software Foundation.
+//
+// **********************************************************************
+
+#include <FreezeScript/TransformDescriptors.h>
+#include <FreezeScript/AssignVisitor.h>
+#include <FreezeScript/Print.h>
+#include <FreezeScript/Functions.h>
+#include <FreezeScript/Exception.h>
+#include <FreezeScript/Util.h>
+#include <IceUtil/UUID.h>
+#include <db_cxx.h>
+
+using namespace std;
+
+namespace FreezeScript
+{
+
+class SymbolTableI;
+typedef IceUtil::Handle<SymbolTableI> SymbolTableIPtr;
+
+class SymbolTableI : public SymbolTable
+{
+public:
+
+    SymbolTableI(const DataFactoryPtr&, const Slice::UnitPtr&, const Slice::UnitPtr&, const ErrorReporterPtr&,
+                 TransformInfo*, const SymbolTablePtr& = SymbolTablePtr());
+
+    virtual void add(const string&, const DataPtr&);
+
+    virtual DataPtr getValue(const EntityNodePtr&) const;
+
+    virtual DataPtr getConstantValue(const string&) const;
+
+    virtual SymbolTablePtr createChild();
+
+    virtual Slice::TypePtr lookupType(const string&);
+
+    virtual DataPtr invokeFunction(const string&, const DataPtr&, const DataList&);
+
+private:
+
+    DataPtr findValue(const string&) const;
+
+    class EntityVisitor : public EntityNodeVisitor
+    {
+    public:
+
+        EntityVisitor(SymbolTableI*);
+
+        virtual void visitIdentifier(const string&);
+        virtual void visitElement(const NodePtr&);
+
+        DataPtr getCurrent() const;
+
+    private:
+
+        SymbolTableI* _table;
+        DataPtr _current;
+        bool _error;
+    };
+
+    friend class EntityVisitor;
+
+    DataFactoryPtr _factory;
+    Slice::UnitPtr _old;
+    Slice::UnitPtr _new;
+    ErrorReporterPtr _errorReporter;
+    TransformInfo* _info;
+    SymbolTablePtr _parent;
+    typedef map<string, DataPtr> DataMap;
+    DataMap _dataMap;
+    DataMap _constantCache;
+};
+
+class ObjectVisitor : public DataVisitor
+{
+public:
+
+    ObjectVisitor(ObjectDataMap&);
+
+    virtual void visitStruct(const StructDataPtr&);
+    virtual void visitSequence(const SequenceDataPtr&);
+    virtual void visitDictionary(const DictionaryDataPtr&);
+    virtual void visitObject(const ObjectRefPtr&);
+
+private:
+
+    ObjectDataMap& _map;
+};
+
+typedef map<string, TransformDescriptorPtr> TransformMap;
+typedef map<string, Slice::TypePtr> RenameMap;
+
+class TransformInfoI : public TransformInfo
+{
+public:
+
+    TransformInfoI(const DataFactoryPtr&, const ErrorReporterPtr&, const Slice::UnitPtr&, const Slice::UnitPtr&);
+
+    virtual bool doDefaultTransform(const Slice::TypePtr&);
+    virtual bool doBaseTransform(const Slice::ClassDefPtr&);
+    virtual Slice::TypePtr getRenamedType(const Slice::TypePtr&);
+    virtual void executeCustomTransform(const DataPtr&, const DataPtr&);
+    virtual bool purgeObjects();
+    virtual ObjectDataMap& getObjectDataMap();
+
+    DataFactoryPtr factory;
+    ErrorReporterPtr errorReporter;
+    Slice::UnitPtr oldUnit;
+    Slice::UnitPtr newUnit;
+    SymbolTablePtr symbolTable;
+    TransformMap transformMap;
+    RenameMap renameMap;
+    ObjectDataMap objectDataMap;
+    Slice::TypePtr oldKeyType;
+    Slice::TypePtr oldValueType;
+    Slice::TypePtr newKeyType;
+    Slice::TypePtr newValueType;
+    Ice::CommunicatorPtr communicator;
+    bool purge;
+    Db* oldDb;
+    DbTxn* oldDbTxn;
+    Db* newDb;
+    DbTxn* newDbTxn;
+};
+
+void assignOrTransform(const DataPtr&, const DataPtr&, bool, const DataFactoryPtr&, const ErrorReporterPtr&,
+                       TransformInfo*);
+
+} // End of namespace FreezeScript
+
+//
+// Descriptor
+//
+FreezeScript::Descriptor::Descriptor(const DescriptorPtr& parent, int line, const DataFactoryPtr& factory,
+                                     const ErrorReporterPtr& errorReporter) :
+    _parent(parent), _line(line), _factory(factory), _errorReporter(errorReporter)
+{
+}
+
+FreezeScript::Descriptor::~Descriptor()
+{
+}
+
+FreezeScript::DescriptorPtr
+FreezeScript::Descriptor::parent() const
+{
+    return _parent;
+}
+
+FreezeScript::NodePtr
+FreezeScript::Descriptor::parse(const string& expr) const
+{
+    return parseExpression(expr, _factory, _errorReporter);
+}
+
+Slice::TypePtr
+FreezeScript::Descriptor::findType(const Slice::UnitPtr& u, const string& type)
+{
+    Slice::TypeList l;
+
+    l = u->lookupType(type, false);
+    if(l.empty())
+    {
+        _errorReporter->error("unknown type `" + type + "'");
+    }
+
+    return l.front();
+}
+
+//
+// SetDescriptor
+//
+FreezeScript::SetDescriptor::SetDescriptor(const DescriptorPtr& parent, int line, const DataFactoryPtr& factory,
+                                           const ErrorReporterPtr& errorReporter,
+                                           const IceXML::Attributes& attributes) :
+    Descriptor(parent, line, factory, errorReporter)
+{
+    DescriptorErrorContext ctx(_errorReporter, "set", _line);
+
+    IceXML::Attributes::const_iterator p;
+
+    string target;
+    p = attributes.find("target");
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `target' is missing");
+    }
+    target = p->second;
+
+    p = attributes.find("value");
+    if(p != attributes.end())
+    {
+        _valueStr = p->second;
+    }
+
+    p = attributes.find("type");
+    if(p != attributes.end())
+    {
+        _type = p->second;
+    }
+
+    p = attributes.find("length");
+    if(p != attributes.end())
+    {
+        _lengthStr = p->second;
+    }
+
+    p = attributes.find("convert");
+    if(p != attributes.end())
+    {
+        _convert = p->second == "true";
+    }
+
+    if(!_valueStr.empty() && !_type.empty())
+    {
+        _errorReporter->error("attributes `value' and 'type' are mutually exclusive");
+    }
+
+    if(_valueStr.empty() && _type.empty() && _lengthStr.empty())
+    {
+        _errorReporter->error("requires a value for attributes `value', 'type' or 'length'");
+    }
+
+    NodePtr node = parse(target);
+    _target = EntityNodePtr::dynamicCast(node);
+    if(!_target)
+    {
+        _errorReporter->error("`target' attribute is not an entity: `" + target + "'");
+    }
+
+    if(!_valueStr.empty())
+    {
+        _value = parse(_valueStr);
+    }
+
+    if(!_lengthStr.empty())
+    {
+        _length = parse(_lengthStr);
+    }
+}
+
+void
+FreezeScript::SetDescriptor::addChild(const DescriptorPtr&)
+{
+    DescriptorErrorContext ctx(_errorReporter, "set", _line);
+    _errorReporter->error("child elements are not supported");
+}
+
+void
+FreezeScript::SetDescriptor::validate()
+{
+}
+
+void
+FreezeScript::SetDescriptor::execute(const SymbolTablePtr& sym, TransformInfo* info)
+{
+    DescriptorErrorContext ctx(_errorReporter, "set", _line);
+
+    DataPtr data = sym->getValue(_target);
+    if(data->readOnly())
+    {
+        ostringstream ostr;
+        ostr << _target;
+        _errorReporter->error("target `" + ostr.str() + "' cannot be modified");
+    }
+
+    DataPtr value;
+    if(_value)
+    {
+        try
+        {
+            value = _value->evaluate(sym);
+        }
+        catch(const EvaluateException& ex)
+        {
+            _errorReporter->error("evaluation of value `" + _valueStr + "' failed:\n" + ex.reason());
+        }
+    }
+
+    Destroyer<DataPtr> valueDestroyer;
+    if(!_type.empty())
+    {
+        assert(!value);
+        Slice::TypePtr type = sym->lookupType(_type);
+        if(!type)
+        {
+            _errorReporter->error("type `" + _type + "' not found");
+        }
+        value = _factory->createObject(type, false);
+        valueDestroyer.set(value);
+    }
+
+    DataPtr length;
+    if(_length)
+    {
+        SequenceDataPtr seq = SequenceDataPtr::dynamicCast(data);
+        if(!seq)
+        {
+            ostringstream ostr;
+            ostr << _target;
+            _errorReporter->error("target `" + ostr.str() + "' is not a sequence");
+        }
+
+        try
+        {
+            length = _length->evaluate(sym);
+        }
+        catch(const EvaluateException& ex)
+        {
+            _errorReporter->error("evaluation of length `" + _lengthStr + "' failed:\n" + ex.reason());
+        }
+
+        DataList& elements = seq->getElements();
+        Ice::Long l = length->integerValue();
+        if(l < 0 || l > INT_MAX)
+        {
+            _errorReporter->error("sequence length " + length->toString() + " is out of range");
+        }
+
+        DataList::size_type len = static_cast<DataList::size_type>(l);
+        if(len < elements.size())
+        {
+            for(DataList::size_type i = len; i < elements.size(); ++i)
+            {
+                elements[i]->destroy();
+            }
+            elements.resize(len);
+        }
+        else if(len > elements.size())
+        {
+            Slice::SequencePtr seqType = Slice::SequencePtr::dynamicCast(seq->getType());
+            assert(seqType);
+            Slice::TypePtr elemType = seqType->type();
+            for(DataList::size_type i = elements.size(); i < len; ++i)
+            {
+                DataPtr v = _factory->create(elemType, false);
+                if(value)
+                {
+                    assignOrTransform(v, value, _convert, _factory, _errorReporter, info);
+                }
+                elements.push_back(v);
+            }
+        }
+    }
+    else
+    {
+        assignOrTransform(data, value, _convert, _factory, _errorReporter, info);
+    }
+}
+
+//
+// DefineDescriptor
+//
+FreezeScript::DefineDescriptor::DefineDescriptor(const DescriptorPtr& parent, int line, const DataFactoryPtr& factory,
+                                                 const ErrorReporterPtr& errorReporter,
+                                                 const IceXML::Attributes& attributes, const Slice::UnitPtr& oldUnit,
+                                                 const Slice::UnitPtr& newUnit) :
+    Descriptor(parent, line, factory, errorReporter)
+{
+    DescriptorErrorContext ctx(_errorReporter, "define", _line);
+
+    IceXML::Attributes::const_iterator p;
+
+    p = attributes.find("name");
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `name' is missing");
+    }
+    _name = p->second;
+
+    p = attributes.find("type");
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `type' is missing");
+    }
+    if(p->second.find("::New") != string::npos)
+    {
+        Slice::TypeList l = newUnit->lookupType(p->second.substr(5), false);
+        if(l.empty())
+        {
+            _errorReporter->error("type `" + p->second + "' not found");
+        }
+        _type = l.front();
+    }
+    else if(p->second.find("::Old") != string::npos)
+    {
+        Slice::TypeList l = oldUnit->lookupType(p->second.substr(5), false);
+        if(l.empty())
+        {
+            _errorReporter->error("type `" + p->second + "' not found");
+        }
+        _type = l.front();
+    }
+    else
+    {
+        Slice::TypeList l = newUnit->lookupType(p->second, false);
+        if(l.empty())
+        {
+            _errorReporter->error("type `" + p->second + "' not found");
+        }
+        _type = l.front();
+    }
+
+    p = attributes.find("value");
+    if(p != attributes.end())
+    {
+        _valueStr = p->second;
+    }
+
+    p = attributes.find("length");
+    if(p != attributes.end())
+    {
+        _lengthStr = p->second;
+    }
+
+    p = attributes.find("convert");
+    if(p != attributes.end())
+    {
+        _convert = p->second == "true";
+    }
+
+    if(!_valueStr.empty())
+    {
+        _value = parse(_valueStr);
+    }
+
+    if(!_lengthStr.empty())
+    {
+        _length = parse(_lengthStr);
+    }
+}
+
+void
+FreezeScript::DefineDescriptor::addChild(const DescriptorPtr&)
+{
+    DescriptorErrorContext ctx(_errorReporter, "define", _line);
+    _errorReporter->error("child elements are not supported");
+}
+
+void
+FreezeScript::DefineDescriptor::validate()
+{
+}
+
+void
+FreezeScript::DefineDescriptor::execute(const SymbolTablePtr& sym, TransformInfo* info)
+{
+    DescriptorErrorContext ctx(_errorReporter, "define", _line);
+
+    DataPtr data = _factory->create(_type, false);
+
+    DataPtr value;
+    if(_value)
+    {
+        try
+        {
+            value = _value->evaluate(sym);
+        }
+        catch(const EvaluateException& ex)
+        {
+            _errorReporter->error("evaluation of value `" + _valueStr + "' failed:\n" + ex.reason());
+        }
+    }
+
+    DataPtr length;
+    if(_length)
+    {
+        SequenceDataPtr seq = SequenceDataPtr::dynamicCast(data);
+        if(!seq)
+        {
+            _errorReporter->error("length attribute specified but type is not a sequence");
+        }
+
+        try
+        {
+            length = _length->evaluate(sym);
+        }
+        catch(const EvaluateException& ex)
+        {
+            _errorReporter->error("evaluation of length `" + _lengthStr + "' failed:\n" + ex.reason());
+        }
+
+        DataList& elements = seq->getElements();
+        Ice::Long l = length->integerValue();
+        if(l < 0 || l > INT_MAX)
+        {
+            _errorReporter->error("sequence length " + length->toString() + " is out of range");
+        }
+
+        DataList::size_type len = static_cast<DataList::size_type>(l);
+        Slice::SequencePtr seqType = Slice::SequencePtr::dynamicCast(seq->getType());
+        assert(seqType);
+        Slice::TypePtr elemType = seqType->type();
+        for(DataList::size_type i = elements.size(); i < len; ++i)
+        {
+            DataPtr v = _factory->create(elemType, false);
+            if(value)
+            {
+                assignOrTransform(v, value, _convert, _factory, _errorReporter, info);
+            }
+            elements.push_back(v);
+        }
+    }
+    else if(value)
+    {
+        assignOrTransform(data, value, _convert, _factory, _errorReporter, info);
+    }
+
+    sym->add(_name, data);
+}
+
+//
+// AddDescriptor
+//
+FreezeScript::AddDescriptor::AddDescriptor(const DescriptorPtr& parent, int line, const DataFactoryPtr& factory,
+                                           const ErrorReporterPtr& errorReporter,
+                                           const IceXML::Attributes& attributes) :
+    Descriptor(parent, line, factory, errorReporter)
+{
+    DescriptorErrorContext ctx(_errorReporter, "add", _line);
+
+    IceXML::Attributes::const_iterator p;
+
+    string target;
+    p = attributes.find("target");
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `target' is missing");
+    }
+    target = p->second;
+
+    p = attributes.find("key");
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `key' is missing");
+    }
+    _keyStr = p->second;
+
+    p = attributes.find("value");
+    if(p != attributes.end())
+    {
+        _valueStr = p->second;
+    }
+
+    p = attributes.find("type");
+    if(p != attributes.end())
+    {
+        _type = p->second;
+    }
+
+    p = attributes.find("convert");
+    if(p != attributes.end())
+    {
+        _convert = p->second == "true";
+    }
+
+    if(!_valueStr.empty() && !_type.empty())
+    {
+        _errorReporter->error("attributes `value' and 'type' are mutually exclusive");
+    }
+
+    NodePtr node = parse(target);
+    _target = EntityNodePtr::dynamicCast(node);
+    if(!_target)
+    {
+        _errorReporter->error("`target' attribute is not an entity: `" + target + "'");
+    }
+
+    assert(!_keyStr.empty());
+    _key = parse(_keyStr);
+
+    if(!_valueStr.empty())
+    {
+        _value = parse(_valueStr);
+    }
+}
+
+void
+FreezeScript::AddDescriptor::addChild(const DescriptorPtr&)
+{
+    DescriptorErrorContext ctx(_errorReporter, "add", _line);
+    _errorReporter->error("child elements are not supported");
+}
+
+void
+FreezeScript::AddDescriptor::validate()
+{
+}
+
+void
+FreezeScript::AddDescriptor::execute(const SymbolTablePtr& sym, TransformInfo* info)
+{
+    DescriptorErrorContext ctx(_errorReporter, "add", _line);
+
+    DataPtr data = sym->getValue(_target);
+    if(data->readOnly())
+    {
+        ostringstream ostr;
+        ostr << _target;
+        _errorReporter->error("target `" + ostr.str() + "' cannot be modified");
+    }
+
+    DictionaryDataPtr dict = DictionaryDataPtr::dynamicCast(data);
+    if(!dict)
+    {
+        ostringstream ostr;
+        ostr << _target;
+        _errorReporter->error("target `" + ostr.str() + "' is not a dictionary");
+    }
+
+    Slice::DictionaryPtr type = Slice::DictionaryPtr::dynamicCast(dict->getType());
+    assert(type);
+
+    DataPtr key;
+    Destroyer<DataPtr> keyDestroyer;
+    try
+    {
+        DataPtr v = _key->evaluate(sym);
+        key = _factory->create(type->keyType(), false);
+        keyDestroyer.set(key);
+        assignOrTransform(key, v, _convert, _factory, _errorReporter, info);
+    }
+    catch(const EvaluateException& ex)
+    {
+        _errorReporter->error("evaluation of key `" + _keyStr + "' failed:\n" + ex.reason());
+    }
+
+    if(dict->getElement(key))
+    {
+        ostringstream ostr;
+        printData(key, ostr);
+        _errorReporter->error("key " + ostr.str() + " already exists in dictionary");
+    }
+
+    DataPtr elem = _factory->create(type->valueType(), false);
+    Destroyer<DataPtr> elemDestroyer(elem);
+
+    DataPtr value;
+    if(_value)
+    {
+        try
+        {
+            value = _value->evaluate(sym);
+        }
+        catch(const EvaluateException& ex)
+        {
+            _errorReporter->error("evaluation of value `" + _valueStr + "' failed:\n" + ex.reason());
+        }
+    }
+
+    Destroyer<DataPtr> valueDestroyer;
+    if(!_type.empty())
+    {
+        assert(!value);
+        Slice::TypePtr type = sym->lookupType(_type);
+        if(!type)
+        {
+            _errorReporter->error("type `" + _type + "' not found");
+        }
+        value = _factory->createObject(type, false);
+        valueDestroyer.set(value);
+    }
+
+    if(value)
+    {
+        assignOrTransform(elem, value, _convert, _factory, _errorReporter, info);
+    }
+    DataMap& map = dict->getElements();
+    map.insert(DataMap::value_type(key, elem));
+    keyDestroyer.release();
+    elemDestroyer.release();
+}
+
+//
+// RemoveDescriptor
+//
+FreezeScript::RemoveDescriptor::RemoveDescriptor(const DescriptorPtr& parent, int line, const DataFactoryPtr& factory,
+                                                 const ErrorReporterPtr& errorReporter,
+                                                 const IceXML::Attributes& attributes) :
+    Descriptor(parent, line, factory, errorReporter)
+{
+    DescriptorErrorContext ctx(_errorReporter, "remove", _line);
+
+    IceXML::Attributes::const_iterator p;
+
+    string target;
+    p = attributes.find("target");
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `target' is missing");
+    }
+    target = p->second;
+
+    p = attributes.find("key");
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `key' is missing");
+    }
+    _keyStr = p->second;
+
+    NodePtr node = parse(target);
+    _target = EntityNodePtr::dynamicCast(node);
+    if(!_target)
+    {
+        _errorReporter->error("`target' attribute is not an entity: `" + target + "'");
+    }
+
+    _key = parse(_keyStr);
+}
+
+void
+FreezeScript::RemoveDescriptor::addChild(const DescriptorPtr&)
+{
+    DescriptorErrorContext ctx(_errorReporter, "remove", _line);
+    _errorReporter->error("child elements are not supported");
+}
+
+void
+FreezeScript::RemoveDescriptor::validate()
+{
+}
+
+void
+FreezeScript::RemoveDescriptor::execute(const SymbolTablePtr& sym, TransformInfo*)
+{
+    DescriptorErrorContext ctx(_errorReporter, "remove", _line);
+
+    DataPtr key;
+    try
+    {
+        key = _key->evaluate(sym);
+    }
+    catch(const EvaluateException& ex)
+    {
+        _errorReporter->error("evaluation of key `" + _keyStr + "' failed:\n" + ex.reason());
+    }
+
+    DataPtr data = sym->getValue(_target);
+    if(data->readOnly())
+    {
+        ostringstream ostr;
+        ostr << _target;
+        _errorReporter->error("target `" + ostr.str() + "' cannot be modified");
+    }
+
+    DictionaryDataPtr dict = DictionaryDataPtr::dynamicCast(data);
+    if(!dict)
+    {
+        ostringstream ostr;
+        ostr << _target;
+        _errorReporter->error("target `" + ostr.str() + "' is not a dictionary");
+    }
+
+    DataMap& map = dict->getElements();
+    DataMap::iterator p = map.find(key);
+    if(p != map.end())
+    {
+        p->first->destroy();
+        p->second->destroy();
+        map.erase(p);
+    }
+}
+
+//
+// DeleteDescriptor
+//
+FreezeScript::DeleteDescriptor::DeleteDescriptor(const DescriptorPtr& parent, int line, const DataFactoryPtr& factory,
+                                                 const ErrorReporterPtr& errorReporter, const IceXML::Attributes&) :
+    Descriptor(parent, line, factory, errorReporter)
+{
+}
+
+void
+FreezeScript::DeleteDescriptor::addChild(const DescriptorPtr&)
+{
+    DescriptorErrorContext ctx(_errorReporter, "delete", _line);
+    _errorReporter->error("child elements are not supported");
+}
+
+void
+FreezeScript::DeleteDescriptor::validate()
+{
+}
+
+void
+FreezeScript::DeleteDescriptor::execute(const SymbolTablePtr&, TransformInfo*)
+{
+    throw DeleteRecordException();
+}
+
+//
+// FailDescriptor
+//
+FreezeScript::FailDescriptor::FailDescriptor(const DescriptorPtr& parent, int line, const DataFactoryPtr& factory,
+                                             const ErrorReporterPtr& errorReporter,
+                                             const IceXML::Attributes& attributes) :
+    Descriptor(parent, line, factory, errorReporter)
+{
+    IceXML::Attributes::const_iterator p;
+
+    p = attributes.find("test");
+    if(p != attributes.end())
+    {
+        _testStr = p->second;
+    }
+
+    p = attributes.find("message");
+    if(p != attributes.end())
+    {
+        _message = p->second;
+    }
+
+    if(!_testStr.empty())
+    {
+        _test = parse(_testStr);
+    }
+
+    if(_message.empty())
+    {
+        ostringstream ostr;
+        ostr << "<fail> executed at line " << line << endl;
+        _message = ostr.str();
+    }
+}
+
+void
+FreezeScript::FailDescriptor::addChild(const DescriptorPtr&)
+{
+    DescriptorErrorContext ctx(_errorReporter, "fail", _line);
+    _errorReporter->error("child elements are not supported");
+}
+
+void
+FreezeScript::FailDescriptor::validate()
+{
+}
+
+void
+FreezeScript::FailDescriptor::execute(const SymbolTablePtr& sym, TransformInfo*)
+{
+    DescriptorErrorContext ctx(_errorReporter, "fail", _line);
+
+    if(_test)
+    {
+        try
+        {
+            DataPtr b = _test->evaluate(sym);
+            BooleanDataPtr bd = BooleanDataPtr::dynamicCast(b);
+            if(!bd)
+            {
+                _errorReporter->error("expression `" + _testStr + "' does not evaluate to a boolean");
+            }
+            if(!bd->booleanValue())
+            {
+                return;
+            }
+        }
+        catch(const EvaluateException& ex)
+        {
+            _errorReporter->error("evaluation of expression `" + _testStr + "' failed:\n" + ex.reason());
+        }
+    }
+
+    throw Exception(__FILE__, __LINE__, _message);
+}
+
+//
+// EchoDescriptor
+//
+FreezeScript::EchoDescriptor::EchoDescriptor(const DescriptorPtr& parent, int line, const DataFactoryPtr& factory,
+                                             const ErrorReporterPtr& errorReporter,
+                                             const IceXML::Attributes& attributes) :
+    Descriptor(parent, line, factory, errorReporter)
+{
+    IceXML::Attributes::const_iterator p;
+
+    p = attributes.find("message");
+    if(p != attributes.end())
+    {
+        _message = p->second;
+    }
+
+    p = attributes.find("value");
+    if(p != attributes.end())
+    {
+        _valueStr = p->second;
+    }
+
+    if(!_valueStr.empty())
+    {
+        _value = parse(_valueStr);
+    }
+}
+
+void
+FreezeScript::EchoDescriptor::addChild(const DescriptorPtr&)
+{
+    DescriptorErrorContext ctx(_errorReporter, "echo", _line);
+    _errorReporter->error("child elements are not supported");
+}
+
+void
+FreezeScript::EchoDescriptor::validate()
+{
+}
+
+void
+FreezeScript::EchoDescriptor::execute(const SymbolTablePtr& sym, TransformInfo*)
+{
+    DescriptorErrorContext ctx(_errorReporter, "echo", _line);
+
+    ostream& out = _errorReporter->stream();
+
+    if(!_message.empty())
+    {
+        out << _message;
+    }
+
+    if(_value)
+    {
+        DataPtr v;
+        try
+        {
+            v = _value->evaluate(sym);
+        }
+        catch(const EvaluateException& ex)
+        {
+            _errorReporter->error("evaluation of value `" + _valueStr + "' failed:\n" + ex.reason());
+        }
+        printData(v, out);
+    }
+
+    out << endl;
+}
+
+//
+// ExecutableContainerDescriptor
+//
+FreezeScript::ExecutableContainerDescriptor::ExecutableContainerDescriptor(const DescriptorPtr& parent, int line,
+                                                                           const DataFactoryPtr& factory,
+                                                                           const ErrorReporterPtr& errorReporter,
+                                                                           const IceXML::Attributes&,
+                                                                           const string& name) :
+    Descriptor(parent, line, factory, errorReporter), _name(name)
+{
+}
+
+void
+FreezeScript::ExecutableContainerDescriptor::addChild(const DescriptorPtr& child)
+{
+    _children.push_back(child);
+}
+
+void
+FreezeScript::ExecutableContainerDescriptor::validate()
+{
+    for(vector<DescriptorPtr>::iterator p = _children.begin(); p != _children.end(); ++p)
+    {
+        (*p)->validate();
+    }
+}
+
+void
+FreezeScript::ExecutableContainerDescriptor::execute(const SymbolTablePtr& sym, TransformInfo* info)
+{
+    for(vector<DescriptorPtr>::iterator p = _children.begin(); p != _children.end(); ++p)
+    {
+        (*p)->execute(sym, info);
+    }
+}
+
+//
+// IfDescriptor
+//
+FreezeScript::IfDescriptor::IfDescriptor(const DescriptorPtr& parent, int line, const DataFactoryPtr& factory,
+                                         const ErrorReporterPtr& errorReporter,
+                                         const IceXML::Attributes& attributes) :
+    ExecutableContainerDescriptor(parent, line, factory, errorReporter, attributes, "if"),
+    Descriptor(parent, line, factory, errorReporter)
+{
+    DescriptorErrorContext ctx(_errorReporter, "if", _line);
+
+    IceXML::Attributes::const_iterator p = attributes.find("test");
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `test' is missing");
+    }
+    _testStr = p->second;
+
+    _test = parse(_testStr);
+}
+
+void
+FreezeScript::IfDescriptor::execute(const SymbolTablePtr& sym, TransformInfo* info)
+{
+    DescriptorErrorContext ctx(_errorReporter, "if", _line);
+
+    try
+    {
+        DataPtr b = _test->evaluate(sym);
+        BooleanDataPtr bd = BooleanDataPtr::dynamicCast(b);
+        if(!bd)
+        {
+            _errorReporter->error("expression `" + _testStr + "' does not evaluate to a boolean");
+        }
+        if(bd->booleanValue())
+        {
+            ExecutableContainerDescriptor::execute(sym, info);
+        }
+    }
+    catch(const EvaluateException& ex)
+    {
+        _errorReporter->error("evaluation of conditional expression `" + _testStr + "' failed:\n" + ex.reason());
+    }
+}
+
+//
+// IterateDescriptor
+//
+FreezeScript::IterateDescriptor::IterateDescriptor(const DescriptorPtr& parent, int line,
+                                                   const DataFactoryPtr& factory,
+                                                   const ErrorReporterPtr& errorReporter,
+                                                   const IceXML::Attributes& attributes) :
+    ExecutableContainerDescriptor(parent, line, factory, errorReporter, attributes, "iterate"),
+    Descriptor(parent, line, factory, errorReporter)
+{
+    DescriptorErrorContext ctx(_errorReporter, "iterate", _line);
+
+    IceXML::Attributes::const_iterator p;
+    string target;
+
+    p = attributes.find("target");
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `target' is missing");
+    }
+    target = p->second;
+
+    p = attributes.find("key");
+    if(p != attributes.end())
+    {
+        _key = p->second;
+    }
+
+    p = attributes.find("value");
+    if(p != attributes.end())
+    {
+        _value = p->second;
+    }
+
+    p = attributes.find("element");
+    if(p != attributes.end())
+    {
+        _element = p->second;
+    }
+
+    p = attributes.find("index");
+    if(p != attributes.end())
+    {
+        _index = p->second;
+    }
+
+    NodePtr node = parse(target);
+    _target = EntityNodePtr::dynamicCast(node);
+    if(!_target)
+    {
+        _errorReporter->error("`target' attribute is not an entity: `" + target + "'");
+    }
+}
+
+void
+FreezeScript::IterateDescriptor::execute(const SymbolTablePtr& sym, TransformInfo* info)
+{
+    DescriptorErrorContext ctx(_errorReporter, "iterate", _line);
+
+    DataPtr data = sym->getValue(_target);
+
+    DictionaryDataPtr dict = DictionaryDataPtr::dynamicCast(data);
+    SequenceDataPtr seq = SequenceDataPtr::dynamicCast(data);
+    if(!dict && !seq)
+    {
+        ostringstream ostr;
+        ostr << _target;
+        _errorReporter->error("target `" + ostr.str() + "' is not a dictionary or sequence");
+    }
+
+    if(dict)
+    {
+        if(!_element.empty())
+        {
+            _errorReporter->error("attribute `element' specified for dictionary target");
+        }
+        if(!_index.empty())
+        {
+            _errorReporter->error("attribute `index' specified for dictionary target");
+        }
+
+        string key = _key;
+        if(key.empty())
+        {
+            key = "key";
+        }
+
+        string value = _value;
+        if(value.empty())
+        {
+            value = "value";
+        }
+
+        DataMap& map = dict->getElements();
+        for(DataMap::iterator p = map.begin(); p != map.end(); ++p)
+        {
+            SymbolTablePtr elemSym = sym->createChild();
+            elemSym->add(key, p->first);
+            elemSym->add(value, p->second);
+            ExecutableContainerDescriptor::execute(elemSym, info);
+        }
+    }
+    else
+    {
+        if(!_key.empty())
+        {
+            _errorReporter->error("attribute `key' specified for sequence target");
+        }
+        if(!_value.empty())
+        {
+            _errorReporter->error("attribute `value' specified for sequence target");
+        }
+
+        string element = _element;
+        if(element.empty())
+        {
+            element = "elem";
+        }
+
+        string index = _index;
+        if(index.empty())
+        {
+            index = "i";
+        }
+
+        DataList& l = seq->getElements();
+        Ice::Long i = 0;
+        for(DataList::iterator p = l.begin(); p != l.end(); ++p, ++i)
+        {
+            SymbolTablePtr elemSym = sym->createChild();
+            elemSym->add(element, *p);
+            elemSym->add(index, _factory->createInteger(i, true));
+            ExecutableContainerDescriptor::execute(elemSym, info);
+        }
+    }
+}
+
+//
+// TransformDescriptor
+//
+FreezeScript::TransformDescriptor::TransformDescriptor(const DescriptorPtr& parent, int line,
+                                                       const DataFactoryPtr& factory,
+                                                       const ErrorReporterPtr& errorReporter,
+                                                       const IceXML::Attributes& attributes,
+                                                       const Slice::UnitPtr& oldUnit, const Slice::UnitPtr& newUnit) :
+    ExecutableContainerDescriptor(parent, line, factory, errorReporter, attributes, "transform"),
+    Descriptor(parent, line, factory, errorReporter), _default(true), _base(true)
+{
+    DescriptorErrorContext ctx(_errorReporter, "transform", _line);
+
+    IceXML::Attributes::const_iterator p;
+
+    string type, rename;
+
+    p = attributes.find("type");
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `type' is missing");
+    }
+    type = p->second;
+
+    p = attributes.find("default");
+    if(p != attributes.end())
+    {
+        if(p->second == "false")
+        {
+            _default = false;
+        }
+    }
+
+    p = attributes.find("base");
+    if(p != attributes.end())
+    {
+        if(p->second == "false")
+        {
+            _base = false;
+        }
+    }
+
+    p = attributes.find("rename");
+    if(p != attributes.end())
+    {
+        rename = p->second;
+    }
+
+    Slice::TypeList l;
+
+    l = newUnit->lookupType(type, false);
+    if(l.empty())
+    {
+        _errorReporter->error("unable to find type `" + type + "' in new Slice definitions");
+    }
+    else
+    {
+        _newType = l.front();
+    }
+
+    if(!rename.empty())
+    {
+        l = oldUnit->lookupType(rename, false);
+        if(l.empty())
+        {
+            _errorReporter->error("unable to find type `" + rename + "' in old Slice definitions");
+        }
+        _renameType = l.front();
+    }
+}
+
+Slice::TypePtr
+FreezeScript::TransformDescriptor::type() const
+{
+    return _newType;
+}
+
+string
+FreezeScript::TransformDescriptor::typeName() const
+{
+    return typeToString(_newType);
+}
+
+Slice::TypePtr
+FreezeScript::TransformDescriptor::renameType() const
+{
+    return _renameType;
+}
+
+string
+FreezeScript::TransformDescriptor::renameTypeName() const
+{
+    string result;
+    if(_renameType)
+    {
+        result = typeToString(_renameType);
+    }
+    return result;
+}
+
+bool
+FreezeScript::TransformDescriptor::doDefaultTransform() const
+{
+    return _default;
+}
+
+bool
+FreezeScript::TransformDescriptor::doBaseTransform() const
+{
+    return _base;
+}
+
+//
+// InitDescriptor
+//
+FreezeScript::InitDescriptor::InitDescriptor(const DescriptorPtr& parent, int line, const DataFactoryPtr& factory,
+                                             const ErrorReporterPtr& errorReporter,
+                                             const IceXML::Attributes& attributes,
+                                             const Slice::UnitPtr& oldUnit, const Slice::UnitPtr& newUnit) :
+    ExecutableContainerDescriptor(parent, line, factory, errorReporter, attributes, "init"),
+    Descriptor(parent, line, factory, errorReporter), _old(oldUnit), _new(newUnit)
+{
+    DescriptorErrorContext ctx(_errorReporter, "init", _line);
+
+    IceXML::Attributes::const_iterator p = attributes.find("type");
+
+    string type;
+
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `type' is missing");
+    }
+    type = p->second;
+
+    Slice::TypeList l = _new->lookupType(type, false);
+    if(l.empty())
+    {
+        _errorReporter->error("unable to find type `" + type + "' in new Slice definitions");
+    }
+    else
+    {
+        _type = l.front();
+    }
+}
+
+void
+FreezeScript::InitDescriptor::initialize(const DataFactoryPtr& factory, const DataPtr& data,
+                                         const Ice::CommunicatorPtr& communicator)
+{
+    //
+    // Create a new symbol table for the initializer and add the value to be initialized
+    // as the symbol "value".
+    //
+    TransformInfo* info = 0;
+
+    // TODO: Initialializers should have access to the main symbol table.
+    SymbolTablePtr sym = new SymbolTableI(factory, _old, _new, _errorReporter, info);
+    sym->add("value", data);
+
+    execute(sym, info);
+}
+
+string
+FreezeScript::InitDescriptor::typeName() const
+{
+    return typeToString(_type);
+}
+
+//
+// RecordDescriptor
+//
+FreezeScript::RecordDescriptor::RecordDescriptor(const DescriptorPtr& parent, int line,
+                                                 const DataFactoryPtr& factory,
+                                                 const ErrorReporterPtr& errorReporter,
+                                                 const IceXML::Attributes& attributes,
+                                                 const Slice::UnitPtr& oldUnit, const Slice::UnitPtr& newUnit) :
+    ExecutableContainerDescriptor(parent, line, factory, errorReporter, attributes, "record"),
+    Descriptor(parent, line, factory, errorReporter), _old(oldUnit), _new(newUnit)
+{
+}
+
+void
+FreezeScript::RecordDescriptor::execute(const SymbolTablePtr& sym, TransformInfo* info)
+{
+    TransformInfoI* infoI = dynamic_cast<TransformInfoI*>(info);
+    assert(infoI);
+
+    //
+    // We need the Instance in order to use BasicStream.
+    //
+    IceInternal::InstancePtr instance = IceInternal::getInstance(infoI->communicator);
+
+    //
+    // Temporarily add an object factory.
+    //
+    infoI->communicator->addObjectFactory(new FreezeScript::ObjectFactory(_factory, _old), "");
+
+    //
+    // Iterate over the database.
+    //
+    Dbc* dbc = 0;
+    infoI->oldDb->cursor(infoI->oldDbTxn, &dbc, 0);
+    try
+    {
+        Dbt dbKey, dbValue;
+        while(dbc->get(&dbKey, &dbValue, DB_NEXT) == 0)
+        {
+            IceInternal::BasicStream inKey(instance.get());
+            inKey.b.resize(dbKey.get_size());
+            memcpy(&inKey.b[0], dbKey.get_data(), dbKey.get_size());
+            inKey.i = inKey.b.begin();
+
+            IceInternal::BasicStream inValue(instance.get());
+            inValue.b.resize(dbValue.get_size());
+            memcpy(&inValue.b[0], dbValue.get_data(), dbValue.get_size());
+            inValue.i = inValue.b.begin();
+            inValue.startReadEncaps();
+
+            IceInternal::BasicStream outKey(instance.get());
+            IceInternal::BasicStream outValue(instance.get());
+            outValue.startWriteEncaps();
+            try
+            {
+                transformRecord(inKey, inValue, outKey, outValue, info);
+                outValue.endWriteEncaps();
+                Dbt dbNewKey(&outKey.b[0], outKey.b.size()), dbNewValue(&outValue.b[0], outValue.b.size());
+                if(infoI->newDb->put(infoI->newDbTxn, &dbNewKey, &dbNewValue, DB_NOOVERWRITE) == DB_KEYEXIST)
+                {
+                    _errorReporter->error("duplicate key encountered");
+                }
+            }
+            catch(const DeleteRecordException&)
+            {
+                // The record is deleted simply by not adding it to the new database.
+            }
+            catch(const ClassNotFoundException& ex)
+            {
+                if(!infoI->purge)
+                {
+                    _errorReporter->error("class " + ex.id + " not found in new Slice definitions");
+                }
+                else
+                {
+                    // The record is deleted simply by not adding it to the new database.
+                    _errorReporter->warning("purging database record due to missing class type " + ex.id);
+                }
+            }
+        }
+    }
+    catch(...)
+    {
+        if(dbc)
+        {
+            dbc->close();
+        }
+        infoI->communicator->removeObjectFactory("");
+        throw;
+    }
+
+    infoI->communicator->removeObjectFactory("");
+
+    if(dbc)
+    {
+        dbc->close();
+    }
+}
+
+void
+FreezeScript::RecordDescriptor::transformRecord(IceInternal::BasicStream& inKey, IceInternal::BasicStream& inValue,
+                                                IceInternal::BasicStream& outKey, IceInternal::BasicStream& outValue,
+                                                TransformInfo* info)
+{
+    TransformInfoI* infoI = dynamic_cast<TransformInfoI*>(info);
+    assert(infoI);
+
+    //
+    // Create data representations of the old key and value types.
+    //
+    _factory->disableInitializers();
+    DataPtr oldKeyData = _factory->create(infoI->oldKeyType, true);
+    Destroyer<DataPtr> oldKeyDataDestroyer(oldKeyData);
+    DataPtr oldValueData = _factory->create(infoI->oldValueType, true);
+    Destroyer<DataPtr> oldValueDataDestroyer(oldValueData);
+
+    //
+    // Unmarshal the old key and value.
+    //
+    oldKeyData->unmarshal(inKey);
+    oldValueData->unmarshal(inValue);
+    infoI->objectDataMap.clear();
+    if(infoI->oldValueType->usesClasses())
+    {
+        inValue.readPendingObjects();
+        ObjectVisitor visitor(infoI->objectDataMap);
+        oldValueData->visit(visitor);
+    }
+    _factory->enableInitializers();
+
+    //
+    // Create data representations of the new key and value types.
+    //
+    DataPtr newKeyData = _factory->create(infoI->newKeyType, false);
+    Destroyer<DataPtr> newKeyDataDestroyer(newKeyData);
+    DataPtr newValueData = _factory->create(infoI->newValueType, false);
+    Destroyer<DataPtr> newValueDataDestroyer(newValueData);
+
+    //
+    // Copy the data from the old key and value to the new key and value, if possible.
+    //
+    TransformVisitor keyVisitor(oldKeyData, _factory, _errorReporter, info);
+    newKeyData->visit(keyVisitor);
+    TransformVisitor valueVisitor(oldValueData, _factory, _errorReporter, info);
+    newValueData->visit(valueVisitor);
+
+    if(!_children.empty())
+    {
+        //
+        // Execute the child descriptors.
+        //
+        // TODO: Revisit identifiers.
+        //
+        SymbolTablePtr st = new SymbolTableI(_factory, _old, _new, _errorReporter, info, infoI->symbolTable);
+        st->add("oldkey", oldKeyData);
+        st->add("newkey", newKeyData);
+        st->add("oldvalue", oldValueData);
+        st->add("newvalue", newValueData);
+        ExecutableContainerDescriptor::execute(st, info);
+    }
+
+    newKeyData->marshal(outKey);
+    newValueData->marshal(outValue);
+    if(infoI->newValueType->usesClasses())
+    {
+        outValue.writePendingObjects();
+    }
+}
+
+//
+// DatabaseDescriptor
+//
+FreezeScript::DatabaseDescriptor::DatabaseDescriptor(const DescriptorPtr& parent, int line,
+                                                     const DataFactoryPtr& factory,
+                                                     const ErrorReporterPtr& errorReporter,
+                                                     const IceXML::Attributes& attributes,
+                                                     const Slice::UnitPtr& oldUnit, const Slice::UnitPtr& newUnit) :
+    ExecutableContainerDescriptor(parent, line, factory, errorReporter, attributes, "database"),
+    Descriptor(parent, line, factory, errorReporter), _old(oldUnit), _new(newUnit)
+{
+    DescriptorErrorContext ctx(_errorReporter, "database", _line);
+
+    IceXML::Attributes::const_iterator p = attributes.find("key");
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `key' is missing");
+    }
+    string keyTypes = p->second;
+
+    p = attributes.find("value");
+    if(p == attributes.end())
+    {
+        _errorReporter->error("required attribute `value' is missing");
+    }
+    string valueTypes = p->second;
+
+    string oldKeyName, newKeyName;
+    string oldValueName, newValueName;
+    string::size_type pos;
+
+    pos = keyTypes.find(',');
+    if(pos == 0 || pos == keyTypes.size())
+    {
+        _errorReporter->error("invalid key type specification `" + keyTypes +"'");
+    }
+    if(pos == string::npos)
+    {
+        oldKeyName = keyTypes;
+        newKeyName = keyTypes;
+    }
+    else
+    {
+        oldKeyName = keyTypes.substr(0, pos);
+        newKeyName = keyTypes.substr(pos + 1);
+    }
+
+    pos = valueTypes.find(',');
+    if(pos == 0 || pos == valueTypes.size())
+    {
+        _errorReporter->error("invalid value type specification `" + valueTypes +"'");
+    }
+    if(pos == string::npos)
+    {
+        oldValueName = valueTypes;
+        newValueName = valueTypes;
+    }
+    else
+    {
+        oldValueName = valueTypes.substr(0, pos);
+        newValueName = valueTypes.substr(pos + 1);
+    }
+
+    //
+    // Look up the Slice definitions for the key and value types.
+    //
+    _oldKey = findType(_old, oldKeyName);
+    _newKey = findType(_new, newKeyName);
+    _oldValue = findType(_old, oldValueName);
+    _newValue = findType(_new, newValueName);
+}
+
+void
+FreezeScript::DatabaseDescriptor::addChild(const DescriptorPtr& child)
+{
+    DescriptorErrorContext ctx(_errorReporter, "database", _line);
+
+    RecordDescriptorPtr rec = RecordDescriptorPtr::dynamicCast(child);
+    if(rec)
+    {
+        if(_record)
+        {
+            _errorReporter->error("only one <record> element can be specified");
+        }
+        _record = rec;
+    }
+
+    ExecutableContainerDescriptor::addChild(child);
+}
+
+void
+FreezeScript::DatabaseDescriptor::execute(const SymbolTablePtr&, TransformInfo* info)
+{
+    TransformInfoI* infoI = dynamic_cast<TransformInfoI*>(info);
+    assert(infoI);
+
+    //
+    // Store the key and value types.
+    //
+    infoI->oldKeyType = _oldKey;
+    infoI->oldValueType = _oldValue;
+    infoI->newKeyType = _newKey;
+    infoI->newValueType = _newValue;
+
+    ExecutableContainerDescriptor::execute(infoI->symbolTable, info);
+}
+
+//
+// TransformDBDescriptor
+//
+FreezeScript::TransformDBDescriptor::TransformDBDescriptor(int line, const DataFactoryPtr& factory,
+                                                           const ErrorReporterPtr& errorReporter,
+                                                           const IceXML::Attributes& attributes,
+                                                           const Slice::UnitPtr& oldUnit,
+                                                           const Slice::UnitPtr& newUnit) :
+    Descriptor(0, line, factory, errorReporter), _old(oldUnit), _new(newUnit),
+    _info(new TransformInfoI(factory, errorReporter, oldUnit, newUnit))
+{
+}
+
+FreezeScript::TransformDBDescriptor::~TransformDBDescriptor()
+{
+    delete _info;
+}
+
+void
+FreezeScript::TransformDBDescriptor::addChild(const DescriptorPtr& child)
+{
+    DescriptorErrorContext ctx(_errorReporter, "transformdb", _line);
+
+    DatabaseDescriptorPtr db = DatabaseDescriptorPtr::dynamicCast(child);
+    TransformDescriptorPtr transform = TransformDescriptorPtr::dynamicCast(child);
+    InitDescriptorPtr init = InitDescriptorPtr::dynamicCast(child);
+
+    if(db)
+    {
+        if(_database)
+        {
+            _errorReporter->error("only one <database> element can be specified");
+        }
+        else
+        {
+            _database = db;
+            _children.push_back(db);
+        }
+    }
+    else if(transform)
+    {
+        string name = transform->typeName();
+        TransformMap::iterator p = _info->transformMap.find(name);
+        if(p != _info->transformMap.end())
+        {
+            _errorReporter->error("transform `" + name + "' specified more than once");
+        }
+        _info->transformMap.insert(TransformMap::value_type(name, transform));
+
+        string renameTypeName = transform->renameTypeName();
+        if(!renameTypeName.empty())
+        {
+            RenameMap::iterator q = _info->renameMap.find(renameTypeName);
+            if(q != _info->renameMap.end())
+            {
+                _errorReporter->error("multiple transform descriptors specify the rename value `" + renameTypeName +
+                                       "'");
+            }
+            _info->renameMap.insert(RenameMap::value_type(renameTypeName, transform->type()));
+        }
+
+        _children.push_back(transform);
+    }
+    else if(init)
+    {
+        string name = init->typeName();
+        _factory->addInitializer(name, init);
+        _children.push_back(init);
+    }
+    else
+    {
+        _errorReporter->error("invalid child element");
+    }
+}
+
+void
+FreezeScript::TransformDBDescriptor::validate()
+{
+    DescriptorErrorContext ctx(_errorReporter, "transformdb", _line);
+
+    if(!_database)
+    {
+        _errorReporter->error("no <database> element specified");
+    }
+
+    for(vector<DescriptorPtr>::iterator p = _children.begin(); p != _children.end(); ++p)
+    {
+        (*p)->validate();
+    }
+}
+
+void
+FreezeScript::TransformDBDescriptor::execute(const SymbolTablePtr&, TransformInfo*)
+{
+    assert(false);
+}
+
+void
+FreezeScript::TransformDBDescriptor::transform(const Ice::CommunicatorPtr& communicator, Db* oldDb, DbTxn* oldDbTxn,
+                                               Db* newDb, DbTxn* newDbTxn, bool purgeObjects)
+{
+    _info->communicator = communicator;
+    _info->oldDb = oldDb;
+    _info->oldDbTxn = oldDbTxn;
+    _info->newDb = newDb;
+    _info->newDbTxn = newDbTxn;
+    _info->purge = purgeObjects;
+
+    try
+    {
+        _database->execute(0, _info);
+    }
+    catch(...)
+    {
+        _info->communicator = 0;
+        _info->oldDb = 0;
+        _info->oldDbTxn = 0;
+        _info->newDb = 0;
+        _info->newDbTxn = 0;
+        throw;
+    }
+
+    _info->communicator = 0;
+    _info->oldDb = 0;
+    _info->oldDbTxn = 0;
+    _info->newDb = 0;
+    _info->newDbTxn = 0;
+}
+
+//
+// SymbolTableI
+//
+FreezeScript::SymbolTableI::SymbolTableI(const DataFactoryPtr& factory, const Slice::UnitPtr& oldUnit,
+                                         const Slice::UnitPtr& newUnit,
+                                         const ErrorReporterPtr& errorReporter, TransformInfo* info,
+                                         const SymbolTablePtr& parent) :
+    _factory(factory), _old(oldUnit), _new(newUnit), _errorReporter(errorReporter), _info(info), _parent(parent)
+{
+}
+
+void
+FreezeScript::SymbolTableI::add(const string& name, const DataPtr& data)
+{
+    DataPtr d = findValue(name);
+    if(d)
+    {
+        _errorReporter->error("`" + name + "' is already defined");
+    }
+
+    _dataMap.insert(DataMap::value_type(name, data));
+}
+
+FreezeScript::DataPtr
+FreezeScript::SymbolTableI::getValue(const EntityNodePtr& entity) const
+{
+    EntityVisitor visitor(const_cast<SymbolTableI*>(this));
+    entity->visit(visitor);
+    DataPtr result = visitor.getCurrent();
+    if(!result)
+    {
+        ostringstream ostr;
+        ostr << "invalid entity `" << entity << "'";
+        _errorReporter->error(ostr.str());
+    }
+
+    return result;
+}
+
+FreezeScript::DataPtr
+FreezeScript::SymbolTableI::getConstantValue(const string& name) const
+{
+    string::size_type pos;
+    Slice::UnitPtr unit;
+    string key;
+
+    DataMap::const_iterator p = _constantCache.find(name);
+    if(p != _constantCache.end())
+    {
+        return p->second;
+    }
+
+    if(_parent)
+    {
+        return _parent->getConstantValue(name);
+    }
+
+    //
+    // Name must start with "::Old" or "::New" to indicate the Slice unit.
+    //
+    pos = name.find("::Old");
+    if(pos == 0)
+    {
+        if(name.length() > 5)
+        {
+            key = name.substr(5);
+            unit = _old;
+        }
+    }
+    else
+    {
+        pos = name.find("::New");
+        if(pos == 0)
+        {
+            if(name.length() > 5)
+            {
+                key = name.substr(5);
+                unit = _new;
+            }
+        }
+    }
+
+    if(key.empty())
+    {
+        _errorReporter->error("invalid constant name `" + name + "'");
+    }
+
+    Slice::ContainedList l = unit->findContents(key);
+    if(l.empty())
+    {
+        _errorReporter->error("unknown constant `" + name + "'");
+    }
+
+    Slice::EnumeratorPtr e = Slice::EnumeratorPtr::dynamicCast(l.front());
+    Slice::ConstPtr c = Slice::ConstPtr::dynamicCast(l.front());
+    if(!e && !c)
+    {
+        _errorReporter->error("`" + name + "' does not refer to a Slice constant or enumerator");
+    }
+
+    DataPtr result;
+
+    if(c)
+    {
+        Slice::TypePtr type = c->type();
+        string value = c->value();
+        Slice::BuiltinPtr b = Slice::BuiltinPtr::dynamicCast(type);
+        if(b)
+        {
+            switch(b->kind())
+            {
+            case Slice::Builtin::KindByte:
+            case Slice::Builtin::KindShort:
+            case Slice::Builtin::KindInt:
+            case Slice::Builtin::KindLong:
+            {
+                string::size_type end;
+                Ice::Long n;
+                if(!IceUtil::stringToInt64(value, n, end))
+                {
+                    assert(false);
+                }
+                result = _factory->createInteger(n, true);
+                break;
+            }
+
+            case Slice::Builtin::KindBool:
+            {
+                result = _factory->createBoolean(value == "true", true);
+                break;
+            }
+
+            case Slice::Builtin::KindFloat:
+            case Slice::Builtin::KindDouble:
+            {
+                double v = strtod(value.c_str(), 0);
+                result = _factory->createDouble(v, true);
+                break;
+            }
+
+            case Slice::Builtin::KindString:
+            {
+                result = _factory->createString(value, true);
+                break;
+            }
+
+            case Slice::Builtin::KindObject:
+            case Slice::Builtin::KindObjectProxy:
+            case Slice::Builtin::KindLocalObject:
+                assert(false);
+            }
+        }
+        else
+        {
+            Slice::EnumPtr en = Slice::EnumPtr::dynamicCast(type);
+            assert(en);
+            Slice::EnumeratorList el = en->getEnumerators();
+            for(Slice::EnumeratorList::iterator q = el.begin(); q != el.end(); ++q)
+            {
+                if((*q)->name() == value)
+                {
+                    e = *q;
+                    break;
+                }
+            }
+            assert(e);
+        }
+    }
+
+    if(!result)
+    {
+        assert(e);
+        result = _factory->create(e->type(), true);
+        EnumDataPtr ed = EnumDataPtr::dynamicCast(result);
+        assert(ed);
+        ed->setValueAsString(e->name());
+    }
+
+    //
+    // Cache the value.
+    //
+    const_cast<DataMap&>(_constantCache).insert(DataMap::value_type(name, result));
+
+    return result;
+}
+
+FreezeScript::SymbolTablePtr
+FreezeScript::SymbolTableI::createChild()
+{
+    return new SymbolTableI(_factory, _old, _new, _errorReporter, _info, this);
+}
+
+Slice::TypePtr
+FreezeScript::SymbolTableI::lookupType(const string& name)
+{
+    Slice::TypeList l = _new->lookupType(name, false);
+    Slice::TypePtr result;
+    if(!l.empty())
+    {
+        result = l.front();
+    }
+    return result;
+}
+
+FreezeScript::DataPtr
+FreezeScript::SymbolTableI::invokeFunction(const string& name, const DataPtr& target, const DataList& args)
+{
+    if(target)
+    {
+        DictionaryDataPtr targetDict = DictionaryDataPtr::dynamicCast(target);
+        if(targetDict && name == "containsKey")
+        {
+            if(args.size() != 1)
+            {
+                _errorReporter->error("containsKey() requires one argument");
+            }
+            Slice::DictionaryPtr dictType = Slice::DictionaryPtr::dynamicCast(targetDict->getType());
+            assert(dictType);
+            DataPtr key = _factory->create(dictType->keyType(), false);
+            assignOrTransform(key, args[0], false, _factory, _errorReporter, _info);
+            DataPtr value = targetDict->getElement(key);
+            return _factory->createBoolean(value ? true : false, false);
+        }
+
+        DataPtr result;
+        if(invokeMemberFunction(name, target, args, result, _factory, _errorReporter))
+        {
+            return result;
+        }
+
+        _errorReporter->error("unknown function `" + name + "' invoked on type " + typeToString(target->getType()));
+    }
+    else
+    {
+        //
+        // Global function.
+        //
+        DataPtr result;
+        if(invokeGlobalFunction(name, args, result, _factory, _errorReporter))
+        {
+            return result;
+        }
+        else
+        {
+            _errorReporter->error("unknown global function `" + name + "'");
+        }
+    }
+
+    return 0;
+}
+
+FreezeScript::DataPtr
+FreezeScript::SymbolTableI::findValue(const string& name) const
+{
+    DataMap::const_iterator p = _dataMap.find(name);
+    if(p != _dataMap.end())
+    {
+        return p->second;
+    }
+
+    if(_parent)
+    {
+        SymbolTableIPtr parentI = SymbolTableIPtr::dynamicCast(_parent);
+        assert(parentI);
+        return parentI->findValue(name);
+    }
+
+    return 0;
+}
+
+FreezeScript::SymbolTableI::EntityVisitor::EntityVisitor(SymbolTableI* table) :
+    _table(table), _error(false)
+{
+}
+
+void
+FreezeScript::SymbolTableI::EntityVisitor::visitIdentifier(const string& name)
+{
+    if(!_error)
+    {
+        if(!_current)
+        {
+            _current = _table->findValue(name);
+        }
+        else
+        {
+            _current = _current->getMember(name);
+        }
+
+        if(!_current)
+        {
+            _error = true;
+        }
+    }
+}
+
+void
+FreezeScript::SymbolTableI::EntityVisitor::visitElement(const NodePtr& value)
+{
+    if(!_error)
+    {
+        assert(_current);
+
+        DataPtr val = value->evaluate(_table);
+        _current = _current->getElement(val);
+
+        if(!_current)
+        {
+            _error = true;
+        }
+    }
+}
+
+FreezeScript::DataPtr
+FreezeScript::SymbolTableI::EntityVisitor::getCurrent() const
+{
+    return _current;
+}
+
+//
+// ObjectVisitor
+//
+FreezeScript::ObjectVisitor::ObjectVisitor(ObjectDataMap& map) :
+    _map(map)
+{
+}
+
+void
+FreezeScript::ObjectVisitor::visitStruct(const StructDataPtr& data)
+{
+    Slice::TypePtr type = data->getType();
+    if(type->usesClasses())
+    {
+        DataMemberMap& members = data->getMembers();
+        for(DataMemberMap::iterator p = members.begin(); p != members.end(); ++p)
+        {
+            p->second->visit(*this);
+        }
+    }
+}
+
+void
+FreezeScript::ObjectVisitor::visitSequence(const SequenceDataPtr& data)
+{
+    Slice::TypePtr type = data->getType();
+    if(type->usesClasses())
+    {
+        DataList& elements = data->getElements();
+        for(DataList::iterator p = elements.begin(); p != elements.end(); ++p)
+        {
+            (*p)->visit(*this);
+        }
+    }
+}
+
+void
+FreezeScript::ObjectVisitor::visitDictionary(const DictionaryDataPtr& data)
+{
+    Slice::TypePtr type = data->getType();
+    if(type->usesClasses())
+    {
+        DataMap& elements = data->getElements();
+        for(DataMap::iterator p = elements.begin(); p != elements.end(); ++p)
+        {
+            //
+            // NOTE: There's no need to visit the key.
+            //
+            p->second->visit(*this);
+        }
+    }
+}
+
+void
+FreezeScript::ObjectVisitor::visitObject(const ObjectRefPtr& data)
+{
+    ObjectDataPtr value = data->getValue();
+    if(value)
+    {
+        ObjectDataMap::iterator p = _map.find(value.get());
+        if(p == _map.end())
+        {
+            _map.insert(ObjectDataMap::value_type(value.get(), 0));
+            DataMemberMap& members = value->getMembers();
+            for(DataMemberMap::iterator q = members.begin(); q != members.end(); ++q)
+            {
+                q->second->visit(*this);
+            }
+        }
+    }
+}
+
+//
+// TransformInfoI
+//
+FreezeScript::TransformInfoI::TransformInfoI(const DataFactoryPtr& fact, const ErrorReporterPtr& err,
+                                             const Slice::UnitPtr& oldU, const Slice::UnitPtr& newU) :
+    factory(fact), errorReporter(err), oldUnit(oldU), newUnit(newU), purge(false), oldDb(0), oldDbTxn(0), newDb(0),
+    newDbTxn(0)
+{
+    symbolTable = new SymbolTableI(factory, oldUnit, newUnit, errorReporter, this);
+}
+
+bool
+FreezeScript::TransformInfoI::doDefaultTransform(const Slice::TypePtr& type)
+{
+    TransformMap::const_iterator p = transformMap.find(typeToString(type));
+    if(p != transformMap.end())
+    {
+        return p->second->doDefaultTransform();
+    }
+    return true;
+}
+
+bool
+FreezeScript::TransformInfoI::doBaseTransform(const Slice::ClassDefPtr& type)
+{
+    TransformMap::const_iterator p = transformMap.find(type->scoped());
+    if(p != transformMap.end())
+    {
+        return p->second->doBaseTransform();
+    }
+    return true;
+}
+
+Slice::TypePtr
+FreezeScript::TransformInfoI::getRenamedType(const Slice::TypePtr& old)
+{
+    RenameMap::iterator p = renameMap.find(typeToString(old));
+    if(p != renameMap.end())
+    {
+        return p->second;
+    }
+    return 0;
+}
+
+void
+FreezeScript::TransformInfoI::executeCustomTransform(const DataPtr& dest, const DataPtr& src)
+{
+    //
+    // Execute the type's transform (if any). Non-nil objects need special consideration,
+    // for two reasons:
+    //
+    // 1. The dest and src arguments are ObjectRef instances whose getType()
+    //    function returns the formal type, which may not match the actual type
+    //    if inheritance is being used. Therefore, we need to look for the
+    //    transform of the actual type of the object.
+    //
+    // 2. It's not sufficient to execute only the transform for the actual type;
+    //    the transform descriptors for base types must also be executed (if not
+    //    explicitly precluded).
+    //
+    // The algorithm goes like this:
+    //
+    // 1. If a transform exists for the actual type, execute it.
+    // 2. If the transform doesn't exist, or if it does exist and does not preclude
+    //    the execution of the base transform, then obtain the base type. If the
+    //    type has no user-defined base class, use Object.
+    // 3. If a base type was found and a transform exists for the base type, execute it.
+    // 4. Repeat step 2.
+    //
+    ObjectRefPtr obj = ObjectRefPtr::dynamicCast(dest);
+    if(obj && obj->getValue())
+    {
+        ObjectDataPtr data = obj->getValue();
+        Slice::TypePtr cls = data->getType(); // Actual type
+        bool transformBase = true;
+        while(cls)
+        {
+            string type = typeToString(cls);
+            TransformMap::const_iterator p = transformMap.find(type);
+            if(p != transformMap.end())
+            {
+                SymbolTablePtr sym = new SymbolTableI(factory, oldUnit, newUnit, errorReporter, this, symbolTable);
+                sym->add("new", dest);
+                sym->add("old", src);
+                p->second->execute(sym, this);
+                transformBase = p->second->doBaseTransform();
+            }
+            Slice::ClassDeclPtr decl = Slice::ClassDeclPtr::dynamicCast(cls);
+            cls = 0;
+            if(transformBase && decl)
+            {
+                Slice::ClassDefPtr def = decl->definition();
+                assert(def);
+                Slice::ClassList bases = def->bases();
+                if(!bases.empty() && !bases.front()->isInterface())
+                {
+                    cls = bases.front()->declaration();
+                }
+                else
+                {
+                    cls = newUnit->builtin(Slice::Builtin::KindObject);
+                }
+            }
+        }
+    }
+    else
+    {
+        string type = typeToString(dest->getType());
+        TransformMap::const_iterator p = transformMap.find(type);
+        if(p != transformMap.end())
+        {
+            SymbolTablePtr sym = new SymbolTableI(factory, oldUnit, newUnit, errorReporter, this, symbolTable);
+            sym->add("new", dest);
+            sym->add("old", src);
+            p->second->execute(sym, this);
+        }
+    }
+}
+
+bool
+FreezeScript::TransformInfoI::purgeObjects()
+{
+    return purge;
+}
+
+FreezeScript::ObjectDataMap&
+FreezeScript::TransformInfoI::getObjectDataMap()
+{
+    return objectDataMap;
+}
+
+//
+// assignOrTransform
+//
+void
+FreezeScript::assignOrTransform(const DataPtr& dest, const DataPtr& src, bool convert, const DataFactoryPtr& factory,
+                                const ErrorReporterPtr& errorReporter, TransformInfo* info)
+{
+    Slice::TypePtr destType = dest->getType();
+    Slice::TypePtr srcType = src->getType();
+    Slice::BuiltinPtr b1 = Slice::BuiltinPtr::dynamicCast(destType);
+    Slice::BuiltinPtr b2 = Slice::BuiltinPtr::dynamicCast(srcType);
+
+    if(!b1 && !b2 && dest->getType()->unit().get() != src->getType()->unit().get())
+    {
+        TransformVisitor v(src, factory, errorReporter, info);
+        dest->visit(v);
+    }
+    else
+    {
+        AssignVisitor v(src, factory, errorReporter, convert);
+        dest->visit(v);
+    }
+}