static ImmutableHashDictionary()
{
// Need to make sure _emptyDictionary gets initialized first, otherwise the constructor for Empty will NRE.
_emptyDictionary = new Dictionary <TKey, TValue>();
Empty = new ImmutableHashDictionary <TKey, TValue>();
}
/// <summary>
/// Converts the current contents of the builder to a new <see cref="ImmutableHashDictionary{TKey, TValue}"/>.
/// </summary>
/// <returns>An <see cref="ImmutableHashDictionary{TKey, TValue}"/>, containing the same entries as the buidler instance.</returns>
/// <remarks>
/// This method is an O(1) operation, as it simply involves wrapping a new <see cref="ImmutableHashDictionary{TKey, TValue}"/>
/// around the <see cref="Dictionary{TKey, TValue}"/> that has been built. The next mutation operation performed on this builder
/// will be at least O(N), as it will require duplicating the entire <see cref="Dictionary{TKey, TValue}"/>, to prevent the
/// previously-created <see cref="ImmutableHashDictionary{TKey, TValue}"/> from being mutated.
/// </remarks>
public ImmutableHashDictionary <TKey, TValue> ToImmutable()
{
var immutableHashDictionary = new ImmutableHashDictionary <TKey, TValue>(CurrentDictionaryForRead, _keyComparer, _valueComparer);
_lastDictionary = _currentDictionary;
_currentDictionary = null;
return(immutableHashDictionary);
}