forked from rburkitt/LinqToServiceNow
/
ExpressionVisitor.cs
121 lines (101 loc) · 4.48 KB
/
ExpressionVisitor.cs
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using System.Linq;
using System.Linq.Expressions;
/**
* LinqToServiceNow
*
* @package LinqToServiceNow
* @author Raymond Burkitt
* @copyright (c) 2013 Technao
* @license http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt
*/
namespace LinqToServiceNow
{
public class ExpressionVisitor
{
private string _encodedQuery = string.Empty;
public string VisitExpression(Utilities.ContinuationOperator continuation, Expression expr)
{
return VisitExpression(continuation, expr, false);
}
public string VisitExpression(Utilities.ContinuationOperator continuation, Expression expr, bool neg)
{
if (expr.NodeType == ExpressionType.Call)
{
MethodCallExpression methodCall = (expr as MethodCallExpression);
if (methodCall.Method.Name == "Contains" & methodCall.Arguments.Count > 1)
VisitContainsExpression(continuation, expr as MethodCallExpression, neg);
else
VisitSimpleMethodCall(continuation, methodCall, neg);
}
else if (expr.NodeType == ExpressionType.Not)
{
UnaryExpression unaryExpr = expr as UnaryExpression;
VisitExpression(continuation, unaryExpr.Operand, true);
}
else
VisitBinaryExpression(continuation, expr as BinaryExpression, neg);
return _encodedQuery;
}
private void VisitBinaryExpression(Utilities.ContinuationOperator continuation, BinaryExpression binExpr, bool neg)
{
ExpressionType oper = binExpr.NodeType;
ExpressionType[] AndOperators = { ExpressionType.And, ExpressionType.AndAlso };
ExpressionType[] OrOperators = { ExpressionType.Or, ExpressionType.OrElse };
ExpressionType[] binOperators = AndOperators.Concat(OrOperators).ToArray();
if (binOperators.Contains(binExpr.NodeType))
{
VisitExpression(continuation, binExpr.Left, neg);
if (binOperators.Contains(binExpr.Left.NodeType) & binOperators.Contains(binExpr.Right.NodeType))
{
if (AndOperators.Contains(binExpr.NodeType))
_encodedQuery += "NQ";
if (OrOperators.Contains(binExpr.NodeType))
_encodedQuery += "^NQ";
}
VisitExpression((Utilities.ContinuationOperator)binExpr.NodeType, binExpr.Right, neg);
}
else
VisitSimpleExpression(continuation, binExpr, neg);
}
private void VisitSimpleExpression(Utilities.ContinuationOperator continuation, BinaryExpression binExpr, bool neg)
{
EncodedQueryExpression encodedQuery = new EncodedQueryExpression {
ContinuationOperator = continuation,
IsNegated = neg,
Operator = (Utilities.RepoExpressionType)binExpr.NodeType,
EncodedQuery = _encodedQuery,
Expression = binExpr
};
if(encodedQuery.HasValue)
_encodedQuery = encodedQuery.Value;
}
private void VisitContainsExpression(Utilities.ContinuationOperator continuation, MethodCallExpression methodCall, bool neg)
{
EncodedQueryExpression encodedQuery = new EncodedQueryExpression {
ContinuationOperator = continuation,
IsNegated = neg,
Operator = Utilities.RepoExpressionType.IN,
EncodedQuery = _encodedQuery,
Expression = methodCall
};
if (encodedQuery.HasValue)
_encodedQuery = encodedQuery.Value;
else
VisitExpression(continuation, methodCall, neg);
}
private void VisitSimpleMethodCall(Utilities.ContinuationOperator continuation, MethodCallExpression methodCall, bool neg)
{
EncodedQueryExpression encodedQuery = new EncodedQueryExpression {
ContinuationOperator = continuation,
IsNegated = neg,
Operator = Utilities.GetRepoExpressionType(methodCall.Method.Name),
EncodedQuery = _encodedQuery,
Expression = methodCall
};
if(encodedQuery.HasValue)
_encodedQuery = encodedQuery.Value;
else
VisitExpression(continuation, methodCall, neg);
}
}
}