sean-m
/
Vanara
mirror of https://github.com/dahall/Vanara.git
1
0
Fork 0
Code Issues Releases Wiki Activity

More work on generic History collection

pull/180/head
dahall 2020-09-25 17:17:51 -06:00
parent e8bb34c109
commit 3c4e5fe12c
1 changed files with 30 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
Core/Collections/History.cs
View File

@ -29,7 +29,8 @@ namespace Vanara.Collections
/// <summary>Adds the specified item as the last history entry and sets the <see cref="Current"/> property to it's value.</summary>
/// <param name="item">The item to add to the history.</param>
void Add(T item);
/// <param name="removeForwardItems"><see langword="true" /> indicates to remove all items forward of the current pointer; <see langword="false"/> leaves the history intact.</param>
void Add(T item, bool removeForwardItems);
/// <summary>Clears the history of all items.</summary>
void Clear();
@ -100,15 +101,15 @@ namespace Vanara.Collections
/// <summary>Indicates the presence of items in the history that can be reached by calling <see cref="SeekBackward"/>.</summary>
/// <value><see langword="true"/> if this instance can seek backward; otherwise, <see langword="false"/>.</value>
public bool CanSeekBackward => GetCurrent()?.Previous != null;
public virtual bool CanSeekBackward => GetCurrent()?.Previous != null;
/// <summary>Indicates the presence of items in the history that can be reached by calling <see cref="SeekForward"/>.</summary>
/// <value><see langword="true"/> if this instance can seek forward; otherwise, <see langword="false"/>.</value>
public bool CanSeekForward => GetCurrent()?.Next != null;
public virtual bool CanSeekForward => GetCurrent()?.Next != null;
/// <summary>Gets or sets the capacity of the history, or the maximum number of items that it will hold.</summary>
/// <value>The history's capacity.</value>
public int Capacity
public virtual int Capacity
{
get => capacity;
set
@ -132,16 +133,31 @@ namespace Vanara.Collections
/// <summary>Gets the value at a pointer within the history that represents the current item.</summary>
/// <value>The current item.</value>
/// <exception cref="System.InvalidOperationException">There are no items in the history.</exception>
public T Current => !(GetCurrent() is null) ? current.Value : throw new InvalidOperationException("There are no items in the history.");
public virtual T Current => !(GetCurrent() is null) ? current.Value : throw new InvalidOperationException("There are no items in the history.");
/// <summary>Gets the items in the history.</summary>
/// <value>The number of items.</value>
public int Count => activeHistory.Count;
public virtual int Count => activeHistory.Count;
/// <summary>Adds the specified item as the last history entry and sets the <see cref="Current"/> property to it's value.</summary>
/// <summary>
/// Adds the specified item as the last history entry and sets the <see cref="Current" /> property to it's value.
/// </summary>
/// <param name="item">The item to add to the history.</param>
public void Add(T item)
/// <param name="removeForwardItems"><see langword="true" /> indicates to remove all items forward of the current pointer; <see langword="false"/> leaves the history intact.</param>
public virtual void Add(T item, bool removeForwardItems = false)
{
if (removeForwardItems && CanSeekForward)
{
var ptr = activeHistory.Last;
var items = new List<T>();
while (ptr != current)
{
items.Add(ptr.Value);
activeHistory.RemoveLast();
ptr = activeHistory.Last;
}
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, items));
}
var added = activeHistory.AddLast(item);
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, item));
if (activeHistory.Count > Capacity)
@ -156,7 +172,7 @@ namespace Vanara.Collections
}
/// <summary>Clears the history of all items.</summary>
public void Clear()
public virtual void Clear()
{
if (Count == 0) return;
activeHistory.Clear();
@ -168,13 +184,13 @@ namespace Vanara.Collections
/// <summary>Returns an enumerator that iterates through the collection.</summary>
/// <returns>A <see cref="IEnumerator{T}"/> that can be used to iterate through the collection.</returns>
public IEnumerator<T> GetEnumerator() => activeHistory.GetEnumerator();
public virtual IEnumerator<T> GetEnumerator() => activeHistory.GetEnumerator();
/// <summary>Gets a specified number of items starting at a location within the history.</summary>
/// <param name="count">The maximum number of items to retrieve. The actual number of items returned may be less if not avaialable.</param>
/// <param name="origin">The reference point within the history at which to start fetching items.</param>
/// <returns>A read-only list of items.</returns>
public IReadOnlyList<T> GetItems(int count, SeekOrigin origin)
public virtual IReadOnlyList<T> GetItems(int count, SeekOrigin origin)
{
if (count == 0 || Count == 0) return (IReadOnlyList<T>)new List<T>(0);
var ptr = origin switch
@ -204,7 +220,7 @@ namespace Vanara.Collections
/// <exception cref="System.ArgumentOutOfRangeException">
/// The number of items to move cannot be accomplished given the number of items in the history and the seek origin.
/// </exception>
public T Seek(int count, SeekOrigin origin)
public virtual T Seek(int count, SeekOrigin origin)
{
if (activeHistory.Count == 0) throw new InvalidOperationException("Cannot seek on an empty history.");
var ptr = origin switch
@ -226,11 +242,11 @@ namespace Vanara.Collections
/// <summary>Seeks one position backwards.</summary>
/// <returns>The value at the new current pointer position.</returns>
public T SeekBackward() => CanSeekBackward ? Seek(-1, SeekOrigin.Current) : default;
public virtual T SeekBackward() => CanSeekBackward ? Seek(-1, SeekOrigin.Current) : default;
/// <summary>Seeks one position forwards.</summary>
/// <returns>The value at the new current pointer position.</returns>
public T SeekForward() => CanSeekForward ? Seek(1, SeekOrigin.Current) : default;
public virtual T SeekForward() => CanSeekForward ? Seek(1, SeekOrigin.Current) : default;
/// <summary>Returns an enumerator that iterates through a collection.</summary>
/// <returns>An <see cref="T:System.Collections.IEnumerator"/> object that can be used to iterate through the collection.</returns>