private Expression PrepareExpression(out IQbservableProvider realProvider)
{
QbservableProviderDiagnostics.DebugPrint(Expression, "TcpServerQuery Received Expression");
var source = Provider.GetSource(argument);
realProvider = source.Provider;
ExpressionVisitor visitor;
Expression preparedExpression = null;
if (!Provider.Options.AllowExpressionsUnrestricted)
{
visitor = new SecurityExpressionVisitor(Provider.Options);
preparedExpression = visitor.Visit(Expression);
}
visitor = ReplaceConstantsVisitor.Create(
typeof(QbservableSourcePlaceholder <TSource>),
source,
typeof(IQbservable <TSource>),
(actualTypeInQuery, actualTypeInServer) =>
{
throw new InvalidOperationException("The client specified the wrong data type for the query." + Environment.NewLine
+ "Client data type: " + actualTypeInQuery.FullName + Environment.NewLine
+ "Actual data type: " + actualTypeInServer.FullName);
});
preparedExpression = visitor.Visit(preparedExpression ?? Expression);
visitor = ReplaceConstantsVisitor.Create(
typeof(DuplexCallback),
(value, _) =>
{
var callback = (DuplexCallback)value;
callback.SetServerProtocol(Provider.Protocol);
return(callback);
},
type => type);
preparedExpression = visitor.Visit(preparedExpression);
QbservableProviderDiagnostics.DebugPrint(preparedExpression, "TcpServerQuery Rewritten Expression");
return(preparedExpression);
}
public Expression PrepareExpression(QbservableProtocol protocol)
{
QbservableProviderDiagnostics.DebugPrint(Expression, "TcpClientQuery Original Expression");
if (!Expression.Type.IsGenericType ||
(Expression.Type.GetGenericTypeDefinition() != typeof(IQbservable <>) &&
Expression.Type.GetGenericTypeDefinition() != typeof(TcpClientQuery <>)))
{
throw new InvalidOperationException("The query must end as an IQbservable<T>.");
}
var visitor = ReplaceConstantsVisitor.CreateForGenericTypeByDefinition(
typeof(TcpClientQuery <>),
(_, actualType) => Activator.CreateInstance(typeof(QbservableSourcePlaceholder <>).MakeGenericType(actualType.GetGenericArguments()[0]), true),
type => typeof(IQbservable <>).MakeGenericType(type.GetGenericArguments()[0]));
var result = visitor.Visit(Expression);
if (visitor.ReplacedConstants == 0)
{
throw new InvalidOperationException("A queryable observable service was not found in the query.");
}
var evaluator = Provider.LocalEvaluator;
if (!evaluator.IsKnownType(Provider.SourceType))
{
evaluator.AddKnownType(Provider.SourceType);
}
var evaluationVisitor = new LocalEvaluationVisitor(evaluator, protocol);
var preparedExpression = evaluationVisitor.Visit(result);
QbservableProviderDiagnostics.DebugPrint(preparedExpression, "TcpClientQuery Rewritten Expression");
return(preparedExpression);
}