substitute static method

String substitute(String fmtString, Map<String, dynamic>? values, { SQLReplaceIdentifierFunction? replace, })

Implementation

static String substitute(String fmtString, Map<String, dynamic>? values,
    {SQLReplaceIdentifierFunction? replace}) {
  final converter = PostgresTextEncoder();
  values ??= const {};
  replace ??= (spec, index) => converter.convert(values![spec.name]);

  final items = <PostgreSQLFormatToken>[];
  PostgreSQLFormatToken? currentPtr;
  final iterator = RuneIterator(fmtString);

  while (iterator.moveNext()) {
    if (currentPtr == null) {
      if (iterator.current == _atSignCodeUnit) {
        currentPtr =
            PostgreSQLFormatToken(PostgreSQLFormatTokenType.variable);
        currentPtr.buffer.writeCharCode(iterator.current);
        items.add(currentPtr);
      } else {
        currentPtr = PostgreSQLFormatToken(PostgreSQLFormatTokenType.text);
        currentPtr.buffer.writeCharCode(iterator.current);
        items.add(currentPtr);
      }
    } else if (currentPtr.type == PostgreSQLFormatTokenType.text) {
      if (iterator.current == _atSignCodeUnit) {
        currentPtr =
            PostgreSQLFormatToken(PostgreSQLFormatTokenType.variable);
        currentPtr.buffer.writeCharCode(iterator.current);
        items.add(currentPtr);
      } else {
        currentPtr.buffer.writeCharCode(iterator.current);
      }
    } else if (currentPtr.type == PostgreSQLFormatTokenType.variable) {
      if (iterator.current == _atSignCodeUnit) {
        iterator.movePrevious();
        if (iterator.current == _atSignCodeUnit) {
          currentPtr.buffer.writeCharCode(iterator.current);
          currentPtr.type = PostgreSQLFormatTokenType.text;
        } else {
          currentPtr =
              PostgreSQLFormatToken(PostgreSQLFormatTokenType.variable);
          currentPtr.buffer.writeCharCode(iterator.current);
          items.add(currentPtr);
        }
        iterator.moveNext();
      } else if (_isIdentifier(iterator.current)) {
        currentPtr.buffer.writeCharCode(iterator.current);
      } else {
        currentPtr = PostgreSQLFormatToken(PostgreSQLFormatTokenType.text);
        currentPtr.buffer.writeCharCode(iterator.current);
        items.add(currentPtr);
      }
    }
  }

  var idx = 1;
  return items.map((t) {
    if (t.type == PostgreSQLFormatTokenType.text) {
      return t.buffer;
    } else if (t.buffer.length == 1 && t.buffer.toString() == '@') {
      return t.buffer;
    } else {

      final identifier = PostgreSQLFormatIdentifier(t.buffer.toString());

      if (values != null && !values.containsKey(identifier.name)) {
        // Format string specified identifier with name ${identifier.name},
        // but key was not present in values.
        return t.buffer;
      }

      final val = replace!(identifier, idx);
      idx++;

      if (identifier.typeCast != null) {
        return '$val::${identifier.typeCast}';
      }

      return val;
    }
  }).join('');
}