public static FilterValidationInfo Validatefilter(string expression)
{
FilterValidationInfo info = new FilterValidationInfo();
info.Valid = true;
if (!string.IsNullOrEmpty(expression))
{
List <ExpressionInfo> expressions = new List <ExpressionInfo>();
ExpressionInfo rootExpression = new ExpressionInfo();
int left = 0;
while (expression[left] == ' ')
{
left++;
}
int right = expression.Length - 1;
while (expression[right] == ' ')
{
right--;
}
rootExpression.Expression = expression;
rootExpression.Left = left;
rootExpression.Right = right;
expressions.Add(rootExpression);
ExtractExpressions(expressions, info);
if (info.Valid)
{
foreach (ExpressionInfo expr in expressions)
{
string err;
bool ok = IsValidExpression(expr.Expression, out err);
info.Valid &= ok;
if (!ok)
{
expr.Error = err;
info.IncorrectExpressions.Add(expr);
}
}
}
}
return(info);
}
static bool Split(string op,
bool binary,
List <ExpressionInfo> expressions,
int idx,
List <Range> constants,
List <Range> braces,
FilterValidationInfo validationInfo)
{
ExpressionInfo parentExpression = expressions[idx];
string expression = parentExpression.Expression;
int operatorPosition = expression.IndexOf(op, 0, StringComparison.InvariantCultureIgnoreCase);
while (operatorPosition != -1)
{
Range quotes = constants.Where(R => R.Left <operatorPosition && R.Right> operatorPosition).FirstOrDefault();
if (quotes == null)
{
Range bracePair = braces.Where(R => R.Left <operatorPosition && R.Right> operatorPosition).FirstOrDefault();
if (bracePair == null)
{
if (!binary && operatorPosition != 0)
{
validationInfo.Valid = false;
validationInfo.Message = "Operator not found";
return(false);
}
if (binary && operatorPosition == 0)
{
validationInfo.Valid = false;
validationInfo.Message = "Operand missing";
return(false);
}
expressions.RemoveAt(idx);
if (binary)
{
string expr1 = expression.Substring(0, operatorPosition - 1).Trim();
ExpressionInfo info1 = new ExpressionInfo();
info1.Expression = expr1;
int left = 0;
while (expression[left] == ' ')
{
left++;
}
info1.Left = parentExpression.Left + left;
info1.Right = info1.Left + expr1.Length;
expressions.Add(info1);
}
{
string expr2 = expression.Substring(operatorPosition + op.Length).Trim();
ExpressionInfo info2 = new ExpressionInfo();
info2.Expression = expr2;
int left = operatorPosition + op.Length;
while (expression[left] == ' ')
{
left++;
}
info2.Left = parentExpression.Left + left;
info2.Right = info2.Left + info2.Expression.Length;
expressions.Add(info2);
}
return(true);
}
}
operatorPosition = expression.IndexOf(op, operatorPosition + 1, StringComparison.InvariantCultureIgnoreCase);
}
return(false);
}
static bool ParseNextExpression(int idx, List <ExpressionInfo> expressions, FilterValidationInfo validationInfo)
{
ExpressionInfo parentExpression = expressions[idx];
string expression = expressions[idx].Expression.Trim();
List <Range> constants = new List <Range>();
List <Range> braces = new List <Range>();
bool started = false;
{
int quotePosition = -1;
Range range = null;
while ((quotePosition = expression.IndexOf('"', quotePosition + 1)) != -1)
{
started = !started;
if (started)
{
range = new Range();
range.Left = quotePosition;
}
else
{
range.Right = quotePosition;
constants.Add(range);
}
}
}
if (started)
{
validationInfo.Valid = false;
validationInfo.Message = "Constant not terminated";
return(false);
}
// braces
int depth = 0;
int lastPoint = 0;
int leftBracePosition = -1;
while (true)
{
int nextLeft = expression.IndexOf('(', lastPoint);
int nextRight = expression.IndexOf(')', lastPoint);
if (nextLeft == -1 && nextRight == -1)
{
break;
}
if (nextLeft < nextRight && nextLeft != -1)
{
if (depth == 0)
{
leftBracePosition = nextLeft;
}
lastPoint = nextLeft + 1;
depth++;
}
else
{
depth--;
if (depth == 0)
{
Range range = new Range()
{
Left = leftBracePosition, Right = nextRight
};
braces.Add(range);
}
lastPoint = nextRight + 1;
}
}
if (depth != 0)
{
validationInfo.Valid = false;
validationInfo.Message = "Bracket expected";
return(false);
}
Range enclosing = braces.Where(R => R.Left == 0 && R.Right == expression.Length - 1).FirstOrDefault();
if (enclosing != null)
{
expressions.RemoveAt(idx);
string expr2 = expression.Substring(1, expression.Length - 2).Trim();
ExpressionInfo info = new ExpressionInfo();
info.Expression = expr2;
int left = 1;
while (expression[left] == ' ')
{
left++;
}
info.Left = parentExpression.Left + left;
int right = 1;
while (expression[expression.Length - right] == ' ')
{
right++;
}
info.Right = parentExpression.Right - right;
expressions.Add(info);
return(true);
}
{
if (Split("or", true, expressions, idx, constants, braces, validationInfo))
{
return(true);
}
}
{
if (Split("and", true, expressions, idx, constants, braces, validationInfo))
{
return(true);
}
}
{
if (Split("not", false, expressions, idx, constants, braces, validationInfo))
{
return(true);
}
if (!validationInfo.Valid)
{
return(false);
}
}
return(false);
}