ImageResizer.Collections.SafeList< T > Class Template Reference

SafeList is mutable, but it uses immutable data structures to minimize the need for locking. The provided manipulation Exposes a immutable list. Changes are made by copying the lists. SafeList is Never perform logic on SafeList directly, always use GetList() or GetCollection() first, followed by SetList(). If you need involved list-fu, use ModifyList and specify a callback. It will execute inside a lock, preventing changes on other threads from overwriting each other. More...

Inheritance diagram for ImageResizer.Collections.SafeList< T >:

Collaboration diagram for ImageResizer.Collections.SafeList< T >:

Public Member Functions
delegate void	ChangedHandler (SafeList< T > sender)
delegate IEnumerable< T >	ListEditor (IList< T > items)
	SafeList (IEnumerable< T > items)
ReadOnlyCollection< T >	GetCollection ()
	Returns an immutable snapshot of the collection More...
IList< T >	GetList ()
	Returns a mutable snapshot of the list More...
void	SetList (IEnumerable< T > list)
	Replaces the current collection with a new one. (copied to ensure safety) Use ModifyList when modifying the list. Use this only when the previous or current state of the list is irrelevant. More...
void	Add (T item)
	Adds the specified item to the end of the list More...
bool	Remove (T item)
	Removes the item from the list More...
void	AddFirst (T item)
	Adds the specified item to the beginning of the list More...
void	ModifyList (ListEditor callback)
	Allows a caller to perform logic on the list inside a lock, and return a modified list. Callbacks should be fast, and should reference the IList they are fed, not this SafeList instance. Calling methods on the SafeList instance will cause a deadlock. More...
bool	Contains (T item)
	Returns true if the collection contains the specified item at the moment. More...
IEnumerator< T >	GetEnumerator ()

Protected Member Functions
void	FireChanged ()

Protected Attributes
volatile ReadOnlyCollection< T >	items
object	writeLock = new object()

Properties
T	First [get]
	Returns the first item in the list. May return null if the list is empty. More...
T	Last [get]
	Returns the first item in the list. May return null if the list is empty. More...
IEnumerable< T >	Reversed [get]

Events
ChangedHandler	Changed

Detailed Description

SafeList is mutable, but it uses immutable data structures to minimize the need for locking. The provided manipulation Exposes a immutable list. Changes are made by copying the lists. SafeList is Never perform logic on SafeList directly, always use GetList() or GetCollection() first, followed by SetList(). If you need involved list-fu, use ModifyList and specify a callback. It will execute inside a lock, preventing changes on other threads from overwriting each other.

Template Parameters

T

Definition at line 19 of file SafeList.cs.

Member Function Documentation

void ImageResizer.Collections.SafeList< T >.Add ( T  item )

inline

Adds the specified item to the end of the list

Parameters

item

Definition at line 73 of file SafeList.cs.

                                {
            lock (writeLock) {
                IList<T> newList = GetList();
                newList.Add(item);
                items = new ReadOnlyCollection<T>(newList);
            }
            FireChanged();
        }

void ImageResizer.Collections.SafeList< T >.AddFirst ( T  item )

inline

Adds the specified item to the beginning of the list

Parameters

item

Definition at line 122 of file SafeList.cs.

                                     {
            lock (writeLock) {
                IList<T> newList = GetList();
                newList.Insert(0, item);
                items = new ReadOnlyCollection<T>(newList);
            }
            FireChanged();
        }

bool ImageResizer.Collections.SafeList< T >.Contains ( T  item )

inline

Returns true if the collection contains the specified item at the moment.

Parameters

item

Returns

Definition at line 150 of file SafeList.cs.

                                     {
            return items.Contains(item);
        }

ReadOnlyCollection<T> ImageResizer.Collections.SafeList< T >.GetCollection ( )

inline

Returns an immutable snapshot of the collection

Returns

Definition at line 47 of file SafeList.cs.

                                                     {
            return items;
        }

IList<T> ImageResizer.Collections.SafeList< T >.GetList ( )

inline

Returns a mutable snapshot of the list

Returns

Definition at line 54 of file SafeList.cs.

                                  {
            return new List<T>(items);
        }

void ImageResizer.Collections.SafeList< T >.ModifyList ( ListEditor  callback )

inline

Allows a caller to perform logic on the list inside a lock, and return a modified list. Callbacks should be fast, and should reference the IList they are fed, not this SafeList instance. Calling methods on the SafeList instance will cause a deadlock.

Parameters

callback

Definition at line 138 of file SafeList.cs.

                                                    {
            lock (writeLock) {
                items = new ReadOnlyCollection<T>(new List<T>(callback(GetList())));
            }
            FireChanged();
        }

bool ImageResizer.Collections.SafeList< T >.Remove ( T  item )

inline

Removes the item from the list

Parameters

item

Definition at line 86 of file SafeList.cs.

                                   {
            lock (writeLock) {
                IList<T> newList = GetList();
                bool removed = newList.Remove(item);
                if (!removed) return false; //The item didn't exist, don't fire changed events.
                items = new ReadOnlyCollection<T>(newList);
            }
            FireChanged();
            return true;
        }

void ImageResizer.Collections.SafeList< T >.SetList ( IEnumerable< T >  list )

inline

Replaces the current collection with a new one. (copied to ensure safety) Use ModifyList when modifying the list. Use this only when the previous or current state of the list is irrelevant.

Parameters

list

Definition at line 63 of file SafeList.cs.

                                                 {
            lock (writeLock) {
                items = new ReadOnlyCollection<T>(new List<T>(list));
            }
            FireChanged();
        }

Property Documentation

T ImageResizer.Collections.SafeList< T >.First

get

Returns the first item in the list. May return null if the list is empty.

Definition at line 99 of file SafeList.cs.

T ImageResizer.Collections.SafeList< T >.Last

get

Returns the first item in the list. May return null if the list is empty.

Definition at line 110 of file SafeList.cs.

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The documentation for this class was generated from the following file:

• C:/Users/nathanael/Documents/resizer/Core/Collections/SafeList.cs