public static IEnumerable <QueryCondition> ParseQueryConditions(this string query)
{
var stringSpan = new StringSpan(query);
stringSpan.MoveToTheNextStartOfString();
while (!stringSpan.Eof)
{
var fieldName = stringSpan.ReadNextString();
var operation = stringSpan.ReadOperation();
if (operation == QueryOperation.In)
{
var value = stringSpan.ReadInValues();
yield return(new QueryCondition
{
FieldName = fieldName,
Values = value.ToArray(),
Operation = operation
});
}
else
{
var value = stringSpan.ReadNextString();
yield return(new QueryCondition
{
FieldName = fieldName,
Values = value.ToSingleArray(),
Operation = operation
});
}
stringSpan.MoveToTheNextStartOfString();
if (stringSpan.Eof)
{
break;
}
var logicalOperator = stringSpan.ReadNextString();
if (logicalOperator.ToLower() != "and")
{
throw new Exception("Only and logical operation is supported for a while");
}
}
}
private static IEnumerable <string> ReadInValues(this StringSpan stringSpan)
{
stringSpan.MoveToTheNextStartOfString();
var arrayIsOpened = stringSpan.CurrentChar == '[';
if (!arrayIsOpened)
{
throw new Exception("Invalid int operation at position: " + stringSpan.PositionStart);
}
stringSpan.MoveStartPosition(1);
stringSpan.SyncEndWithStart();
while (!stringSpan.Eof)
{
var value = stringSpan.ReadNextStringFromArray();
yield return(value);
stringSpan.SyncStartWithEnd();
if (stringSpan.CurrentChar <= ' ')
{
stringSpan.MoveToTheNextStartOfString();
stringSpan.SyncEndWithStart();
}
if (stringSpan.CurrentChar == ']')
{
stringSpan.MoveStartPosition(1);
stringSpan.SyncEndWithStart();
break;
}
if (stringSpan.CurrentChar != ',')
{
stringSpan.MoveStartPosition(EscapeSequence, c => c == ',' || c == ']');
}
stringSpan.MoveStartPosition(1);
stringSpan.SyncEndWithStart();
}
}
private static string ReadNextString(this StringSpan stringSpan)
{
stringSpan.MoveToTheNextStartOfString();
var isString = stringSpan.CurrentChar == CharToEscape;
if (isString)
{
stringSpan.MoveEndPosition(EscapeSequence, c => c == CharToEscape, 1);
stringSpan.MoveEndPosition(1);
return(stringSpan.GetCurrentValue(EscapeSequence, StringToEscape));
}
stringSpan.MoveEndPosition(EscapeSequence, c => c <= ' ');
return(stringSpan.GetCurrentValue());
}
