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WeakCollection now accepts a custom EqualityComparer to be specified

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git-svn-id: file:///srv/devel/repo-conversion/nusu@193 d2e56fa2-650e-0410-a79f-9358c0239efd
This commit is contained in:
Markus Ewald 2010-03-30 11:02:04 +00:00
parent b8dbf8f40d
commit f0289632f6
1 changed files with 45 additions and 35 deletions
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80
Source/Collections/WeakCollection.cs
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@ -107,8 +107,22 @@ namespace Nuclex.Support.Collections {
/// Internal list of weak references that are unpacking when accessed through
/// the WeakCollection's interface.
/// </param>
public WeakCollection(IList<WeakReference<ItemType>> items) {
public WeakCollection(IList<WeakReference<ItemType>> items) :
this(items, EqualityComparer<ItemType>.Default) { }
/// <summary>Initializes a new weak reference collection</summary>
/// <param name="items">
/// Internal list of weak references that are unpacking when accessed through
/// the WeakCollection's interface.
/// </param>
/// <param name="comparer">
/// Comparer used to identify and compare items to each other
/// </param>
public WeakCollection(
IList<WeakReference<ItemType>> items, IEqualityComparer<ItemType> comparer
) {
this.items = items;
this.comparer = comparer;
}
/// <summary>
@ -198,8 +212,6 @@ namespace Nuclex.Support.Collections {
/// this method, if possible.
/// </remarks>
public int IndexOf(ItemType item) {
EqualityComparer<ItemType> comparer = EqualityComparer<ItemType>.Default;
for(int index = 0; index < this.items.Count; ++index) {
ItemType itemAtIndex = this.items[index].Target;
if((itemAtIndex == null) || (item == null)) {
@ -207,7 +219,7 @@ namespace Nuclex.Support.Collections {
return index;
}
} else {
if(comparer.Equals(itemAtIndex, item)) {
if(this.comparer.Equals(itemAtIndex, item)) {
return index;
}
}
@ -243,24 +255,20 @@ namespace Nuclex.Support.Collections {
/// True if item was successfully removed from the WeakCollection; otherwise, false.
/// </returns>
public bool Remove(ItemType item) {
EqualityComparer<ItemType> comparer = EqualityComparer<ItemType>.Default;
lock(this) {
for(int index = 0; index < this.items.Count; ++index) {
ItemType itemAtIndex = this.items[index].Target;
if((itemAtIndex == null) || (item == null)) {
if(ReferenceEquals(item, itemAtIndex)) {
this.items.RemoveAt(index);
return true;
}
} else {
if(comparer.Equals(item, itemAtIndex)) {
this.items.RemoveAt(index);
return true;
}
for(int index = 0; index < this.items.Count; ++index) {
ItemType itemAtIndex = this.items[index].Target;
if((itemAtIndex == null) || (item == null)) {
if(ReferenceEquals(item, itemAtIndex)) {
this.items.RemoveAt(index);
return true;
}
} else {
if(this.comparer.Equals(item, itemAtIndex)) {
this.items.RemoveAt(index);
return true;
}
}
} // lock(this)
}
return false;
}
@ -303,30 +311,32 @@ namespace Nuclex.Support.Collections {
/// Removes the items that have been garbage collected from the collection
/// </summary>
public void RemoveDeadItems() {
lock(this) {
int eliminatedItemCount = 0;
int eliminatedItemCount = 0;
// Eliminate all items that have been garbage collected by shifting
for(int index = 0; index + eliminatedItemCount < this.items.Count; ++index) {
if(!this.items[index].IsAlive) {
++eliminatedItemCount;
this.items[index] = this.items[index + eliminatedItemCount];
}
// Eliminate all items that have been garbage collected by shifting
for(int index = 0; index + eliminatedItemCount < this.items.Count; ++index) {
if(!this.items[index].IsAlive) {
++eliminatedItemCount;
} else {
this.items[index] = this.items[index + eliminatedItemCount];
++index;
}
}
// If any garbage collected items were found, resize the collection so
// the space that became empty in the previous shifting process will be freed
if(eliminatedItemCount > 0) {
int endIndex = this.items.Count - eliminatedItemCount;
for(int index = this.items.Count - 1; index >= endIndex; --index) {
this.items.RemoveAt(index);
}
// If any garbage collected items were found, resize the collection so
// the space that became empty in the previous shifting process will be freed
if(eliminatedItemCount > 0) {
int endIndex = this.items.Count - eliminatedItemCount;
for(int index = this.items.Count - 1; index >= endIndex; --index) {
this.items.RemoveAt(index);
}
}
}
/// <summary>Weak references to the items contained in the collection</summary>
private IList<WeakReference<ItemType>> items;
/// <summary>Used to identify and compare items in the collection</summary>
private IEqualityComparer<ItemType> comparer;
/// <summary>Synchronization root for threaded accesses to this collection</summary>
private object syncRoot;