Tests and fixes for double-enumeration on AddRange and adding of null to PopsicleList

1 files changed, 33 insertions, 5 deletions

diff --git a/src/ProtocolBuffers/Collections/PopsicleList.cs b/src/ProtocolBuffers/Collections/PopsicleList.cs
index dc5c5836..3de97f89 100644
--- a/src/ProtocolBuffers/Collections/PopsicleList.cs
+++ b/src/ProtocolBuffers/Collections/PopsicleList.cs
@@ -42,6 +42,7 @@ namespace Google.ProtocolBuffers.Collections
     /// </summary>

     public sealed class PopsicleList<T> : IPopsicleList<T>, ICastArray

     {

+        private static readonly bool CheckForNull = default(T) == null;

         private static readonly T[] EmptySet = new T[0];

 

         private List<T> items;

@@ -65,6 +66,10 @@ namespace Google.ProtocolBuffers.Collections
         public void Insert(int index, T item)

         {

             ValidateModification();

+            if (CheckForNull)

+            {

+                ThrowHelper.ThrowIfNull(item);

+            }

             items.Insert(index, item);

         }

 

@@ -87,6 +92,10 @@ namespace Google.ProtocolBuffers.Collections
             set

             {

                 ValidateModification();

+                if (CheckForNull)

+                {

+                    ThrowHelper.ThrowIfNull(value);

+                }

                 items[index] = value;

             }

         }

@@ -94,6 +103,10 @@ namespace Google.ProtocolBuffers.Collections
         public void Add(T item)

         {

             ValidateModification();

+            if (CheckForNull)

+            {

+                ThrowHelper.ThrowIfNull(item);

+            }

             items.Add(item);

         }

 

@@ -145,15 +158,30 @@ namespace Google.ProtocolBuffers.Collections
 

         public void Add(IEnumerable<T> collection)

         {

-            if (readOnly)

+            ValidateModification();

+            ThrowHelper.ThrowIfNull(collection);

+

+            if (!CheckForNull || collection is PopsicleList<T>)

             {

-                throw new NotSupportedException("List is read-only");

+                items.AddRange(collection);

             }

-            if (items == null)

+            else

             {

-                items = new List<T>();

+                // Assumption, it's ok to enumerate collections more than once.

+                if (collection is ICollection<T>)

+                {

+                    ThrowHelper.ThrowIfAnyNull(collection);

+                    items.AddRange(collection);

+                }

+                else

+                {

+                    foreach (T item in collection)

+                    {

+                        ThrowHelper.ThrowIfNull(item);

+                        items.Add(item);

+                    }

+                }

             }

-            items.AddRange(collection);

         }

 

         private void ValidateModification()