/// <summary>
/// Recursively translates an Expression to an LDAP filter (RFC 1960).
/// See formal definition of RFC 1960 at the bottom of this Microsoft doc page.
/// https://docs.microsoft.com/en-us/windows/desktop/adsi/search-filter-syntax
/// </summary>
/// <param name="expr">The Expression body to convert.</param>
/// <param name="p">The ParameterExpression associated with the body.</param>
/// <returns>A string containing an equivalent LDAP filter.</returns>
public string ExpressionToString(Expression expr, IReadOnlyCollection <ParameterExpression> p)
{
switch (expr.NodeType)
{
case ExpressionType.MemberAccess:
return(_MemberToString(expr as MemberExpression, p));
case ExpressionType.Constant:
return(_ConstExprToString(expr, p));
case ExpressionType.AndAlso:
return(BooleanAlgebra.AndOrExprToString(expr, p, "&"));
case ExpressionType.OrElse:
return(BooleanAlgebra.AndOrExprToString(expr, p, "|"));
case ExpressionType.Not:
return(BooleanAlgebra.NotExprToString(expr, p));
case ExpressionType.Equal:
return(_MaybeStringCompareToExpr(expr, p, "=")
?? _ComparisonExprToString(expr, p, "="));
case ExpressionType.GreaterThanOrEqual:
return(_MaybeStringCompareToExpr(expr, p, ">=")
?? _ComparisonExprToString(expr, p, ">="));
case ExpressionType.LessThanOrEqual:
return(_MaybeStringCompareToExpr(expr, p, "<=")
?? _ComparisonExprToString(expr, p, "<="));
case ExpressionType.Call:
return(_CallExprToString(expr, p));
// These are not implemented in RFC 1960, so translate via negation.
case ExpressionType.GreaterThan:
return(_Negate(_MaybeStringCompareToExpr(expr, p, "<=", ">")
?? _ComparisonExprToString(expr, p, /* not */ "<=")));
case ExpressionType.LessThan:
return(_Negate(_MaybeStringCompareToExpr(expr, p, ">=", "<")
?? _ComparisonExprToString(expr, p, /* not */ ">=")));
case ExpressionType.NotEqual:
return(_Negate(_MaybeStringCompareToExpr(expr, p, /* not */ "=")
?? _ComparisonExprToString(expr, p, /* not */ "=")));
case ExpressionType.Conditional: /* ternary */
return(_TernaryToBooleanAlgebra(expr, p));
// Low-priority/do not implement:
default:
throw new NotImplementedException(
$"Linq-to-LDAP not implemented for {expr.NodeType}. \n"
+ "Use local variables to remove algebraic expressions and method calls, \n"
+ "and reduce Linq expression complexity to boolean algebra and string ops.\n"
+ "Please see the Linq2Ldap project site.");
}
}
public CompilerCore(
CompilerOptions options,
Strings strings = null,
BooleanAlgebra booleanAlgebra = null,
ValueUtil valueUtil = null
)
{
Options = options;
Strings = strings ?? new Strings(this);
BooleanAlgebra = booleanAlgebra ?? new BooleanAlgebra(this);
ValueUtil = valueUtil ?? new ValueUtil(Options);
}
