internalRefresh method

@override bool internalRefresh()

Implementation

@override
bool internalRefresh() {
  flags &= ~NOTIFIED;

  if ((flags & RUNNING) != 0) {
    return false;
  }

  // If this computed signal has subscribed to updates from its dependencies
  // (TRACKING flag set) and none of them have notified about changes (OUTDATED
  // flag not set), then the computed value can't have changed.
  if ((flags & (OUTDATED | TRACKING)) == TRACKING) {
    return true;
  }
  flags &= ~OUTDATED;

  if (internalGlobalVersion == globalVersion) {
    return true;
  }
  internalGlobalVersion = globalVersion;

  // Mark this computed signal running before checking the dependencies for value
  // changes, so that the RUNNING flag can be used to notice cyclical dependencies.
  flags |= RUNNING;
  if (version > 0 && !needsToRecompute()) {
    flags &= ~RUNNING;
    return true;
  }

  final prevContext = evalContext;
  try {
    prepareSources();
    evalContext = this;
    final val = fn();
    if (!_isInitialized ||
        (flags & HAS_ERROR) != 0 ||
        _internalValue != val ||
        version == 0) {
      internalValue = val;
      flags &= ~HAS_ERROR;
      version++;
    }
  } catch (err, stack) {
    error = SignalEffectException(err, stack);
    flags |= HAS_ERROR;
    version++;
  }
  evalContext = prevContext;
  cleanupSources();
  flags &= ~RUNNING;
  return true;
}