SurrogateSelector.cs

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namespace System.Runtime.Serialization;
 
public class SurrogateSelector : ISurrogateSelector
{
    internal readonly SurrogateHashtable _surrogates = new SurrogateHashtable(32);
 
    internal ISurrogateSelector _nextSelector;
 
    public virtual void AddSurrogate(Type type, StreamingContext context, ISerializationSurrogate surrogate)
    {
        if (type == null)
        {
            throw new ArgumentNullException("type");
        }
        if (surrogate == null)
        {
            throw new ArgumentNullException("surrogate");
        }
        SurrogateKey key = new SurrogateKey(type, context);
        _surrogates.Add(key, surrogate);
    }
 
    private static bool HasCycle(ISurrogateSelector selector)
    {
        ISurrogateSelector surrogateSelector = selector;
        ISurrogateSelector surrogateSelector2 = selector;
        while (surrogateSelector != null)
        {
            surrogateSelector = surrogateSelector.GetNextSelector();
            if (surrogateSelector == null)
            {
                return true;
            }
            if (surrogateSelector == surrogateSelector2)
            {
                return false;
            }
            surrogateSelector = surrogateSelector.GetNextSelector();
            surrogateSelector2 = surrogateSelector2.GetNextSelector();
            if (surrogateSelector == surrogateSelector2)
            {
                return false;
            }
        }
        return true;
    }
 
    public virtual void ChainSelector(ISurrogateSelector selector)
    {
        if (selector == null)
        {
            throw new ArgumentNullException("selector");
        }
        if (selector == this)
        {
            throw new SerializationException(System.SR.Serialization_SurrogateCycle);
        }
        if (!HasCycle(selector))
        {
            throw new ArgumentException(System.SR.Serialization_SurrogateCycleInArgument, "selector");
        }
        ISurrogateSelector nextSelector = selector.GetNextSelector();
        ISurrogateSelector surrogateSelector = selector;
        while (nextSelector != null && nextSelector != this)
        {
            surrogateSelector = nextSelector;
            nextSelector = nextSelector.GetNextSelector();
        }
        if (nextSelector == this)
        {
            throw new ArgumentException(System.SR.Serialization_SurrogateCycle, "selector");
        }
        nextSelector = selector;
        ISurrogateSelector surrogateSelector2 = selector;
        while (nextSelector != null)
        {
            nextSelector = ((nextSelector != surrogateSelector) ? nextSelector.GetNextSelector() : GetNextSelector());
            if (nextSelector == null)
            {
                break;
            }
            if (nextSelector == surrogateSelector2)
            {
                throw new ArgumentException(System.SR.Serialization_SurrogateCycle, "selector");
            }
            nextSelector = ((nextSelector != surrogateSelector) ? nextSelector.GetNextSelector() : GetNextSelector());
            surrogateSelector2 = ((surrogateSelector2 != surrogateSelector) ? surrogateSelector2.GetNextSelector() : GetNextSelector());
            if (nextSelector == surrogateSelector2)
            {
                throw new ArgumentException(System.SR.Serialization_SurrogateCycle, "selector");
            }
        }
        ISurrogateSelector nextSelector2 = _nextSelector;
        _nextSelector = selector;
        if (nextSelector2 != null)
        {
            surrogateSelector.ChainSelector(nextSelector2);
        }
    }
 
    public virtual ISurrogateSelector? GetNextSelector()
    {
        return _nextSelector;
    }
 
    public virtual ISerializationSurrogate? GetSurrogate(Type type, StreamingContext context, out ISurrogateSelector selector)
    {
        if (type == null)
        {
            throw new ArgumentNullException("type");
        }
        selector = this;
        SurrogateKey key = new SurrogateKey(type, context);
        ISerializationSurrogate serializationSurrogate = (ISerializationSurrogate)_surrogates[key];
        if (serializationSurrogate != null)
        {
            return serializationSurrogate;
        }
        if (_nextSelector != null)
        {
            return _nextSelector.GetSurrogate(type, context, out selector);
        }
        return null;
    }
 
    public virtual void RemoveSurrogate(Type type, StreamingContext context)
    {
        if (type == null)
        {
            throw new ArgumentNullException("type");
        }
        SurrogateKey key = new SurrogateKey(type, context);
        _surrogates.Remove(key);
    }
}