takeString function

String takeString(Pointer<Void> fn(Pointer<Pointer<Utf8>> out), String context)

Run fn with a NULL char **out_json, expectAimuxError the returned error, copy the owned C string out and free it.

Implementation

String takeString(
    Pointer<Void> Function(Pointer<Pointer<Utf8>> out) fn, String context) {
  final out = calloc<Pointer<Utf8>>();
  try {
    expectAimuxError(fn(out), context);
    final p = out.value;
    if (p == nullptr) throw StateError('aimux ffi: $context: NULL result');
    try {
      return p.toDartString();
    } finally {
      aimuxFreeString(p);
    }
  } finally {
    calloc.free(out);
  }
}