internal static VfpExpression Rewrite(VfpExpression expression)
{
var rewriter = new XmlToCursorMoveToInnerExpressionRewriter(expression);
if (!rewriter._xmlToCursors.Any())
{
return(expression);
}
expression = rewriter.Visit(expression);
foreach (var cursorName in rewriter._xmlToCursorsToBeRemoved)
{
expression = XmlToCursorExpressionRemover.Remove(expression, cursorName);
}
return(expression);
}
protected override VfpExpressionBinding VisitVfpExpressionBinding(VfpExpressionBinding binding)
{
var isFilterBinding = binding.Expression is VfpFilterExpression;
if (isFilterBinding)
{
_filterBindings.Push(binding);
}
binding = base.VisitVfpExpressionBinding(binding);
if (isFilterBinding)
{
var expression = binding.Expression;
foreach (var cursorName in _xmlToCursorsToBeRemoved)
{
expression = XmlToCursorExpressionRemover.Remove(expression, cursorName);
}
_xmlToCursorsToBeRemoved.Clear();
_filterBindings.Pop();
binding = expression.BindAs(binding.Variable.VariableName);
}
if (!_filterBindings.Any())
{
return(binding);
}
var filterBinding = _filterBindings.Peek();
if (filterBinding == null)
{
return(binding);
}
var scan = binding.Expression as VfpScanExpression;
if (scan == null)
{
return(binding);
}
if (!_xmlToCursors.ContainsKey(binding.VariableName))
{
return(binding);
}
var xmlToCursors = _xmlToCursors[binding.VariableName];
if (!xmlToCursors.Any())
{
return(binding);
}
foreach (var xmlToCursor in xmlToCursors)
{
var xmlToCursorExpression = xmlToCursor.XmlToCursor;
_count++;
var variableReference = xmlToCursorExpression.ItemType.ToTypeUsage().Variable("Xml" + _count);
var xmlToCursorScan = VfpExpressionBuilder.XmlToCursorScan(xmlToCursorExpression.Parameter, xmlToCursorExpression.CursorName + "_j");
var xmlToCursorBinding = xmlToCursorScan.BindAs(variableReference.VariableName);
var xmlToCursorProperty = VfpExpressionBuilder.XmlToCursorProperty(variableReference.ResultType, variableReference);
var scanProperty = GetScanProperty(binding.Variable, xmlToCursorExpression.Property);
var comparison = scanProperty.ExpressionEquals(xmlToCursorProperty);
var joinVariableReference = binding.VariableType.Variable(binding.VariableName);
var joinExpression = binding.InnerJoin(xmlToCursorBinding, comparison, binding.Expression.ResultType);
_xmlToCursorsToBeRemoved.Add(xmlToCursorExpression.CursorName);
binding = joinExpression.BindAs(joinVariableReference.VariableName);
}
return(binding);
}