public ExtensionAttribute(string configuration, string expression) : base(configuration, expression)
{
SqlFlags = SqlFlags.None;
ExpectExpression = true;
ServerSideOnly = true;
PreferServerSide = true;
}
public SqlExpression(Type?systemType, string expr, int precedence, SqlFlags flags, params ISqlExpression[] parameters)
{
if (parameters == null)
{
throw new ArgumentNullException(nameof(parameters));
}
foreach (var value in parameters)
{
if (value == null)
{
throw new ArgumentNullException(nameof(parameters));
}
}
SystemType = systemType;
Expr = expr;
Precedence = precedence;
Parameters = parameters;
Flags = flags;
}
public static SqlExpression BuildSqlExpression(SqlExtension root, Type systemType, int precedence, SqlFlags sqlFlags)
{
var sb = new StringBuilder();
var resolvedParams = new Dictionary <SqlExtensionParam, string>();
var resolving = new HashSet <SqlExtensionParam>();
var newParams = new List <ISqlExpression>();
Func <string, string, string> valueProvider = null;
Stack <SqlExtension> current = new Stack <SqlExtension>();
valueProvider = (name, delimiter) =>
{
var found = root.GetParametersByName(name);
if (current.Count != 0)
{
found = current.Peek().GetParametersByName(name).Concat(found);
}
string result = null;
foreach (var p in found)
{
string paramValue;
if (resolvedParams.TryGetValue(p, out paramValue))
{
result = paramValue;
}
else
{
if (resolving.Contains(p))
{
throw new InvalidOperationException("Circular reference");
}
resolving.Add(p);
var ext = p.Extension;
if (ext != null)
{
current.Push(ext);
paramValue = ResolveExpressionValues(ext.Expr, valueProvider);
current.Pop();
}
else
{
sb.Length = 0;
if (p.Expression != null)
{
paramValue = string.Format("{{{0}}}", newParams.Count);
newParams.Add(p.Expression);
}
}
resolvedParams.Add(p, paramValue);
if (string.IsNullOrEmpty(paramValue))
{
continue;
}
if (!string.IsNullOrEmpty(result))
{
result = result + delimiter;
}
result = result + paramValue;
}
if (delimiter == null && !string.IsNullOrEmpty(result))
{
break;
}
}
return(result);
};
var expr = ResolveExpressionValues(root.Expr, valueProvider);
var sqlExpression = new SqlExpression(systemType, expr, precedence, sqlFlags, newParams.ToArray());
return(sqlExpression);
}
