internal void Compile(params object[] args)
{
if (this.fnQuery == null)
{
// first identify the query provider being used
Expression body = this.query.Body;
ConstantExpression root = RootQueryableFinder.Find(body) as ConstantExpression;
if (root == null && args != null && args.Length > 0)
{
Expression replaced = ExpressionReplacer.ReplaceAll(
body,
this.query.Parameters.ToArray(),
args.Select((a, i) => Expression.Constant(a, this.query.Parameters[i].Type)).ToArray()
);
body = PartialEvaluator.Eval(replaced);
root = RootQueryableFinder.Find(body) as ConstantExpression;
}
if (root == null)
{
throw new InvalidOperationException("Could not find query provider");
}
// ask the query provider to compile the query by 'executing' the lambda expression
IQueryProvider provider = ((IQueryable)root.Value).Provider;
Delegate result = (Delegate)provider.Execute(this.query);
System.Threading.Interlocked.CompareExchange(ref this.fnQuery, result, null);
}
}
private Expression BuildExecutionPlan(Expression expression)
{
var lambda = expression as LambdaExpression;
if (lambda != null)
{
expression = lambda.Body;
}
var projection = Translate(expression);
var rootQueryable = new RootQueryableFinder().Find(expression);
var provider = Expression.Convert(
Expression.Property(rootQueryable, typeof(IQueryable).GetProperty("Provider")),
typeof(MongoQueryProvider));
return(new ExecutionBuilder().Build(projection, provider));
}
private Expression Translate(Expression expression)
{
var rootQueryable = new RootQueryableFinder().Find(expression);
var elementType = ((IQueryable)((ConstantExpression)rootQueryable).Value).ElementType;
expression = PartialEvaluator.Evaluate(expression, CanBeEvaluatedLocally);
expression = new FieldBinder().Bind(expression, elementType);
expression = new QueryBinder(this, expression).Bind(expression);
expression = new AggregateRewriter().Rewrite(expression);
expression = new RedundantFieldRemover().Remove(expression);
expression = new RedundantSubqueryRemover().Remove(expression);
expression = new OrderByRewriter().Rewrite(expression);
expression = new RedundantFieldRemover().Remove(expression);
expression = new RedundantSubqueryRemover().Remove(expression);
return(expression);
}
