[linqbridge] push by azizatif - Fixed issue #21: GroupBy fails on null keys on 2011-04-30 16:19 GMT

[linqb...@googlecode.com]

Revision: c74eb37b988b
Author: azizatif
Date: Sat Apr 30 07:13:04 2011
Log: Fixed issue #21: GroupBy fails on null keys
http://code.google.com/p/linqbridge/source/detail?r=c74eb37b988b

Modified:
/src/Lookup.cs
/test/LINQBridge.Tests/EnumerableFixture.cs

=======================================
--- /src/Lookup.cs Sat Apr 30 05:48:09 2011
+++ /src/Lookup.cs Sat Apr 30 07:13:04 2011
@@ -45,19 +45,35 @@
internal sealed class Lookup<TKey, TElement> : ILookup<TKey, TElement>
{
private readonly Dictionary<TKey, IGrouping<TKey, TElement>> _map;
+ private readonly List<TKey> _orderedKeys; // in order of insertion
+ private IGrouping<TKey, TElement> _nullGrouping;

internal Lookup(IEqualityComparer<TKey> comparer)
{
_map = new Dictionary<TKey, IGrouping<TKey,
TElement>>(comparer);
+ _orderedKeys = new List<TKey>();
}

internal void Add(IGrouping<TKey, TElement> item)
{
- _map.Add(item.Key, item);
+ var key = item.Key;
+ if (key == null)
+ {
+ if (_nullGrouping != null)
+ throw new ArgumentException("An item with the same key
has already been added.");
+ _nullGrouping = item;
+ }
+ else
+ {
+ _map.Add(key, item);
+ }
+ _orderedKeys.Add(key);
}

internal IEnumerable<TElement> Find(TKey key)
{
+ if (key == null)
+ return _nullGrouping;
IGrouping<TKey, TElement> grouping;
return _map.TryGetValue(key, out grouping) ? grouping : null;
}
@@ -79,6 +95,8 @@
{
get
{
+ if (key == null)
+ return _nullGrouping ?? Enumerable.Empty<TElement>();
IGrouping<TKey, TElement> result;
return _map.TryGetValue(key, out result) ? result :
Enumerable.Empty<TElement>();
}
@@ -90,7 +108,7 @@

public bool Contains(TKey key)
{
- return _map.ContainsKey(key);
+ return key == null ? _nullGrouping != null :
_map.ContainsKey(key);
}

/// <summary>
@@ -103,9 +121,9 @@
{
if (resultSelector == null)
throw new ArgumentNullException("resultSelector");
-
- foreach (var pair in _map)
- yield return resultSelector(pair.Key, pair.Value);
+
+ foreach (var grouping in this)
+ yield return resultSelector(grouping.Key, grouping);
}

/// <summary>
@@ -114,7 +132,8 @@

public IEnumerator<IGrouping<TKey, TElement>> GetEnumerator()
{
- return _map.Values.GetEnumerator();
+ foreach (var key in _orderedKeys)
+ yield return key == null ? _nullGrouping : _map[key];
}

IEnumerator IEnumerable.GetEnumerator()
=======================================
--- /test/LINQBridge.Tests/EnumerableFixture.cs Sat Apr 30 06:02:19 2011
+++ /test/LINQBridge.Tests/EnumerableFixture.cs Sat Apr 30 07:13:04 2011
@@ -913,6 +913,34 @@

result.AssertEquals("M\u00FCller:43", "Meier:47");
}
+
+ [Test(Description
= "http://code.google.com/p/linqbridge/issues/detail?id=21")]
+ public void GroupBy_NullKey()
+ {
+ var arr = new[] { "notnull", null };
+
+ var groups = arr.GroupBy(s => s);
+ using (var group = groups.GetEnumerator())
+ {
+ Assert.That(group.MoveNext(), Is.True);
+ Assert.That(group.Current.Key, Is.EqualTo("notnull"));
+ using (var item = group.Current.GetEnumerator())
+ {
+ Assert.That(item.MoveNext(), Is.True);
+ Assert.That(item.Current, Is.EqualTo("notnull"));
+ Assert.That(item.MoveNext(), Is.False);
+ }
+ Assert.That(group.MoveNext(), Is.True);
+ Assert.That(group.Current.Key, Is.Null);
+ using (var item = group.Current.GetEnumerator())
+ {
+ Assert.That(item.MoveNext(), Is.True);
+ Assert.That(item.Current, Is.Null);
+ Assert.That(item.MoveNext(), Is.False);
+ }
+ Assert.That(group.MoveNext(), Is.False);
+ }
+ }

class Pet
{