/// <summary>
/// Calculates the strength of the given <paramref name="password"/> and
/// fires the <c>ScoreUpdated</c> event if the calculation succeeded.
/// The function protects against too frequent updates by cancelling
/// calculations that are still running while a new calculation was already
/// started. It is therefore safe to call this method in quick succession.
/// </summary>
/// <param name="password"></param>
private void CalculateResult(string password)
{
// The provided password will sometimes be null when the dialog was
// closed before our calc thread got a chance to do its thing, so
// we need to handle this case here.
if (password == null)
{
return;
}
// This will avoid updating the UI too often on quick password input
for (int i = 0; i < 10; i++)
{
Thread.Sleep(5);
if (_cts.IsCancellationRequested)
{
return;
}
}
// Now we should be good to calculate
PasswordStrengthResult result = new PasswordStrengthResult();
result.PasswordLength = password.Length;
if (result.PasswordLength > PW_MIN_LENGTH)
{
result.StrengthPoints = result.PasswordLength;
}
else
{
result.StrengthPoints = (int)(result.PasswordLength / 2);
}
for (int i = 0; i < password.Length; i++)
{
char c = password[i];
// Uppercase
if (c >= 65 && c <= 90)
{
if (!result.UppercaseUsed)
{
result.StrengthPoints += 2;
result.UppercaseUsed = true;
}
}
// Lowercase
else if (c >= 97 && c <= 122)
{
if (!result.LowercaseUsed)
{
result.LowercaseUsed = true;
}
}
// Digit
else if (c >= 48 && c <= 57)
{
if (!result.DigitsUsed)
{
result.StrengthPoints += 2;
result.DigitsUsed = true;
}
}
// Symbol
else
{
if (!result.SymbolsUsed)
{
result.StrengthPoints += 2;
result.SymbolsUsed = true;
}
}
if (result.AllCharClassesUsed)
{
break; // No need to look any further
}
if (_cts.IsCancellationRequested)
{
return;
}
}
if (result.StrengthPoints < STRENGTH_POINTS_MIN_MEDIUM)
{
result.Rating = PasswordRating.POOR;
}
else if (result.StrengthPoints < STRENGTH_POINTS_MIN_GOOD)
{
result.Rating = PasswordRating.MEDIUM;
}
else
{
result.Rating = PasswordRating.GOOD;
}
// Last chance to detect cancellation
if (_cts.IsCancellationRequested)
{
return;
}
// Fire score updated event
ScoreUpdated?.Invoke(this, new ScoreUpdatedEventArgs(result));
}
public ScoreUpdatedEventArgs(PasswordStrengthResult passwordScore)
{
Score = passwordScore;
}