protected override Expression VisitExtension(Expression node)
{
QueryNode query = node as QueryNode;
if (query != null)
{
return(Expression.Constant(query.Execute(sqliteProvider, options)));
}
else
{
return(base.VisitExtension(node));
}
}
public override object Execute(Expression inputExpression)
{
Stopwatch watch = Stopwatch.StartNew();
Expression partiallyEvaluatedExpression = PartialEvaluator.Eval(inputExpression, CanBeEvaluatedStatically);
QueryExecutionOptions options = new QueryExecutionOptions();
Expression expression = new ConvertToQueryAstVisitor(options).Visit(partiallyEvaluatedExpression);
// options have been initialized by ConvertToQueryAstVisitor, start logging:
if (options.HasLoggers)
{
options.WriteLogLine("Input expression: " + inputExpression);
options.WriteLogLine("Partially evaluated expression: " + partiallyEvaluatedExpression);
options.WriteLogLine("Converted to Query AST: " + expression);
}
expression = new OptimizeQueryExpressionVisitor().Visit(expression);
if (options.HasLoggers)
{
options.WriteLogLine("Optimized Query AST: " + expression);
options.WriteLogLine("Query preparation time: " + watch.Elapsed);
}
object result;
// If the whole query was converted, execute it:
QueryNode query = expression as QueryNode;
if (query != null)
{
result = query.Execute(this, options);
}
else
{
// Query not converted completely: we have to use a LINQ-To-Objects / LINQ-To-Profiler mix
expression = new ExecuteAllQueriesVisitor(this, options).Visit(expression);
if (expression.Type.IsValueType)
{
expression = Expression.Convert(expression, typeof(object));
}
var lambdaExpression = Expression.Lambda <Func <object> >(expression);
result = lambdaExpression.Compile()();
}
watch.Stop();
options.WriteLogLine("Total query execution time: " + watch.Elapsed);
return(result);
}
