JoinHashLookupBuilder.cs

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using System.Collections.Generic;
using System.Threading;
 
namespace System.Linq.Parallel;
 
internal sealed class JoinHashLookupBuilder<TElement, TOrderKey, THashKey> : HashLookupBuilder<TElement, TOrderKey, THashKey>
{
    private struct JoinBaseHashBuilder : IBaseHashBuilder<TElement, TOrderKey>
    {
        private readonly HashLookup<THashKey, HashLookupValueList<TElement, TOrderKey>> _base;
 
        public JoinBaseHashBuilder(HashLookup<THashKey, HashLookupValueList<TElement, TOrderKey>> baseLookup)
        {
            _base = baseLookup;
        }
 
        public bool Add(THashKey hashKey, TElement element, TOrderKey orderKey)
        {
            HashLookupValueList<TElement, TOrderKey> value = default(HashLookupValueList<TElement, TOrderKey>);
            if (!_base.TryGetValue(hashKey, ref value))
            {
                value = new HashLookupValueList<TElement, TOrderKey>(element, orderKey);
                _base.Add(hashKey, value);
                return false;
            }
            if (value.Add(element, orderKey))
            {
                _base[hashKey] = value;
            }
            return true;
        }
    }
 
    private sealed class JoinHashLookup : HashJoinHashLookup<THashKey, TElement, TOrderKey>
    {
        private readonly HashLookup<THashKey, HashLookupValueList<TElement, TOrderKey>> _base;
 
        internal JoinHashLookup(HashLookup<THashKey, HashLookupValueList<TElement, TOrderKey>> baseLookup)
        {
            _base = baseLookup;
        }
 
        public override bool TryGetValue(THashKey key, ref HashLookupValueList<TElement, TOrderKey> value)
        {
            return _base.TryGetValue(key, ref value);
        }
    }
 
    private readonly QueryOperatorEnumerator<Pair<TElement, THashKey>, TOrderKey> _dataSource;
 
    private readonly IEqualityComparer<THashKey> _keyComparer;
 
    internal JoinHashLookupBuilder(QueryOperatorEnumerator<Pair<TElement, THashKey>, TOrderKey> dataSource, IEqualityComparer<THashKey> keyComparer)
    {
        _dataSource = dataSource;
        _keyComparer = keyComparer;
    }
 
    public override HashJoinHashLookup<THashKey, TElement, TOrderKey> BuildHashLookup(CancellationToken cancellationToken)
    {
        HashLookup<THashKey, HashLookupValueList<TElement, TOrderKey>> baseLookup = new HashLookup<THashKey, HashLookupValueList<TElement, TOrderKey>>(_keyComparer);
        BuildBaseHashLookup<JoinBaseHashBuilder, TElement, TOrderKey>(baseHashBuilder: new JoinBaseHashBuilder(baseLookup), dataSource: _dataSource, cancellationToken: cancellationToken);
        return new JoinHashLookup(baseLookup);
    }
 
    protected override void Dispose(bool disposing)
    {
        _dataSource.Dispose();
    }
}