40 lines
1.5 KiB
C#
40 lines
1.5 KiB
C#
|
using System;
|
||
|
|
using System.Collections.Generic;
|
||
|
|
using System.Linq;
|
||
|
|
|
||
|
|
namespace PCL.Core.Utils.Diff
|
||
|
|
{
|
||
|
|
public class ItemDiff
|
||
|
|
{
|
||
|
|
public static ItemDiffResult<T> ComputeDiff<T, TKey>(
|
||
|
|
IEnumerable<T> oldItems,
|
||
|
|
IEnumerable<T> newItems,
|
||
|
|
Func<T, TKey> keySelector,
|
||
|
|
IEqualityComparer<TKey>? keyComparer = null)
|
||
|
|
where TKey : notnull
|
||
|
|
{
|
||
|
|
ArgumentNullException.ThrowIfNull(oldItems);
|
||
|
|
ArgumentNullException.ThrowIfNull(newItems);
|
||
|
|
ArgumentNullException.ThrowIfNull(keySelector);
|
||
|
|
|
||
|
|
var comparer = keyComparer ?? EqualityComparer<TKey>.Default;
|
||
|
|
|
||
|
|
var oldDict = oldItems.ToDictionary(keySelector, comparer);
|
||
|
|
var newDict = newItems.ToDictionary(keySelector, comparer);
|
||
|
|
|
||
|
|
var oldKeys = new HashSet<TKey>(oldDict.Keys, comparer);
|
||
|
|
var newKeys = new HashSet<TKey>(newDict.Keys, comparer);
|
||
|
|
|
||
|
|
var addedKeys = new HashSet<TKey>(newKeys.Except(oldKeys, comparer), comparer);
|
||
|
|
var removedKeys = new HashSet<TKey>(oldKeys.Except(newKeys, comparer), comparer);
|
||
|
|
var commonKeys = new HashSet<TKey>(oldKeys.Intersect(newKeys, comparer), comparer);
|
||
|
|
|
||
|
|
var added = addedKeys.Select(k => newDict[k]).ToList();
|
||
|
|
var removed = removedKeys.Select(k => oldDict[k]).ToList();
|
||
|
|
var unchanged = commonKeys.Select(k => newDict[k]).ToList();
|
||
|
|
|
||
|
|
return new ItemDiffResult<T>(added, removed, unchanged);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|