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Merge pull request #950 from cvium/replace_priority_queue

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Replace OptimizedPriorityQueue source with NuGet reference
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Vasily 2019-02-20 14:39:52 +03:00 committed by GitHub
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6 changed files with 2 additions and 752 deletions
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402
MediaBrowser.Providers/Manager/GenericPriorityQueue.cs
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@ -1,402 +0,0 @@
using System;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
//TODO Fix namespace or replace
namespace Priority_Queue
{
/// <summary>
/// Credit: https://github.com/BlueRaja/High-Speed-Priority-Queue-for-C-Sharp
/// A copy of StablePriorityQueue which also has generic priority-type
/// </summary>
/// <typeparam name="TItem">The values in the queue. Must extend the GenericPriorityQueue class</typeparam>
/// <typeparam name="TPriority">The priority-type. Must extend IComparable&lt;TPriority&gt;</typeparam>
public sealed class GenericPriorityQueue<TItem, TPriority> : IFixedSizePriorityQueue<TItem, TPriority>
where TItem : GenericPriorityQueueNode<TPriority>
where TPriority : IComparable<TPriority>
{
private int _numNodes;
private TItem[] _nodes;
private long _numNodesEverEnqueued;
/// <summary>
/// Instantiate a new Priority Queue
/// </summary>
/// <param name="maxNodes">The max nodes ever allowed to be enqueued (going over this will cause undefined behavior)</param>
public GenericPriorityQueue(int maxNodes)
{
#if DEBUG
if (maxNodes <= 0)
{
throw new InvalidOperationException("New queue size cannot be smaller than 1");
}
#endif
_numNodes = 0;
_nodes = new TItem[maxNodes + 1];
_numNodesEverEnqueued = 0;
}
/// <summary>
/// Returns the number of nodes in the queue.
/// O(1)
/// </summary>
public int Count => _numNodes;
/// <summary>
/// Returns the maximum number of items that can be enqueued at once in this queue. Once you hit this number (ie. once Count == MaxSize),
/// attempting to enqueue another item will cause undefined behavior. O(1)
/// </summary>
public int MaxSize => _nodes.Length - 1;
/// <summary>
/// Removes every node from the queue.
/// O(n) (So, don't do this often!)
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Clear()
{
Array.Clear(_nodes, 1, _numNodes);
_numNodes = 0;
}
/// <summary>
/// Returns (in O(1)!) whether the given node is in the queue. O(1)
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool Contains(TItem node)
{
#if DEBUG
if (node == null)
{
throw new ArgumentNullException(nameof(node));
}
if (node.QueueIndex < 0 || node.QueueIndex >= _nodes.Length)
{
throw new InvalidOperationException("node.QueueIndex has been corrupted. Did you change it manually? Or add this node to another queue?");
}
#endif
return (_nodes[node.QueueIndex] == node);
}
/// <summary>
/// Enqueue a node to the priority queue. Lower values are placed in front. Ties are broken by first-in-first-out.
/// If the queue is full, the result is undefined.
/// If the node is already enqueued, the result is undefined.
/// O(log n)
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Enqueue(TItem node, TPriority priority)
{
#if DEBUG
if (node == null)
{
throw new ArgumentNullException(nameof(node));
}
if (_numNodes >= _nodes.Length - 1)
{
throw new InvalidOperationException("Queue is full - node cannot be added: " + node);
}
if (Contains(node))
{
throw new InvalidOperationException("Node is already enqueued: " + node);
}
#endif
node.Priority = priority;
_numNodes++;
_nodes[_numNodes] = node;
node.QueueIndex = _numNodes;
node.InsertionIndex = _numNodesEverEnqueued++;
CascadeUp(_nodes[_numNodes]);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private void Swap(TItem node1, TItem node2)
{
//Swap the nodes
_nodes[node1.QueueIndex] = node2;
_nodes[node2.QueueIndex] = node1;
//Swap their indicies
int temp = node1.QueueIndex;
node1.QueueIndex = node2.QueueIndex;
node2.QueueIndex = temp;
}
//Performance appears to be slightly better when this is NOT inlined o_O
private void CascadeUp(TItem node)
{
//aka Heapify-up
int parent = node.QueueIndex / 2;
while (parent >= 1)
{
var parentNode = _nodes[parent];
if (HasHigherPriority(parentNode, node))
break;
//Node has lower priority value, so move it up the heap
Swap(node, parentNode); //For some reason, this is faster with Swap() rather than (less..?) individual operations, like in CascadeDown()
parent = node.QueueIndex / 2;
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private void CascadeDown(TItem node)
{
//aka Heapify-down
TItem newParent;
int finalQueueIndex = node.QueueIndex;
while (true)
{
newParent = node;
int childLeftIndex = 2 * finalQueueIndex;
//Check if the left-child is higher-priority than the current node
if (childLeftIndex > _numNodes)
{
//This could be placed outside the loop, but then we'd have to check newParent != node twice
node.QueueIndex = finalQueueIndex;
_nodes[finalQueueIndex] = node;
break;
}
var childLeft = _nodes[childLeftIndex];
if (HasHigherPriority(childLeft, newParent))
{
newParent = childLeft;
}
//Check if the right-child is higher-priority than either the current node or the left child
int childRightIndex = childLeftIndex + 1;
if (childRightIndex <= _numNodes)
{
var childRight = _nodes[childRightIndex];
if (HasHigherPriority(childRight, newParent))
{
newParent = childRight;
}
}
//If either of the children has higher (smaller) priority, swap and continue cascading
if (newParent != node)
{
//Move new parent to its new index. node will be moved once, at the end
//Doing it this way is one less assignment operation than calling Swap()
_nodes[finalQueueIndex] = newParent;
int temp = newParent.QueueIndex;
newParent.QueueIndex = finalQueueIndex;
finalQueueIndex = temp;
}
else
{
//See note above
node.QueueIndex = finalQueueIndex;
_nodes[finalQueueIndex] = node;
break;
}
}
}
/// <summary>
/// Returns true if 'higher' has higher priority than 'lower', false otherwise.
/// Note that calling HasHigherPriority(node, node) (ie. both arguments the same node) will return false
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private bool HasHigherPriority(TItem higher, TItem lower)
{
var cmp = higher.Priority.CompareTo(lower.Priority);
return (cmp < 0 || (cmp == 0 && higher.InsertionIndex < lower.InsertionIndex));
}
/// <summary>
/// Removes the head of the queue (node with minimum priority; ties are broken by order of insertion), and returns it.
/// If queue is empty, result is undefined
/// O(log n)
/// </summary>
public bool TryDequeue(out TItem item)
{
if (_numNodes <= 0)
{
item = default(TItem);
return false;
}
#if DEBUG
if (!IsValidQueue())
{
throw new InvalidOperationException("Queue has been corrupted (Did you update a node priority manually instead of calling UpdatePriority()?" +
"Or add the same node to two different queues?)");
}
#endif
var returnMe = _nodes[1];
Remove(returnMe);
item = returnMe;
return true;
}
/// <summary>
/// Resize the queue so it can accept more nodes. All currently enqueued nodes are remain.
/// Attempting to decrease the queue size to a size too small to hold the existing nodes results in undefined behavior
/// O(n)
/// </summary>
public void Resize(int maxNodes)
{
#if DEBUG
if (maxNodes <= 0)
{
throw new InvalidOperationException("Queue size cannot be smaller than 1");
}
if (maxNodes < _numNodes)
{
throw new InvalidOperationException("Called Resize(" + maxNodes + "), but current queue contains " + _numNodes + " nodes");
}
#endif
TItem[] newArray = new TItem[maxNodes + 1];
int highestIndexToCopy = Math.Min(maxNodes, _numNodes);
for (int i = 1; i <= highestIndexToCopy; i++)
{
newArray[i] = _nodes[i];
}
_nodes = newArray;
}
/// <summary>
/// Returns the head of the queue, without removing it (use Dequeue() for that).
/// If the queue is empty, behavior is undefined.
/// O(1)
/// </summary>
public TItem First
{
get
{
#if DEBUG
if (_numNodes <= 0)
{
throw new InvalidOperationException("Cannot call .First on an empty queue");
}
#endif
return _nodes[1];
}
}
/// <summary>
/// This method must be called on a node every time its priority changes while it is in the queue.
/// <b>Forgetting to call this method will result in a corrupted queue!</b>
/// Calling this method on a node not in the queue results in undefined behavior
/// O(log n)
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void UpdatePriority(TItem node, TPriority priority)
{
#if DEBUG
if (node == null)
{
throw new ArgumentNullException(nameof(node));
}
if (!Contains(node))
{
throw new InvalidOperationException("Cannot call UpdatePriority() on a node which is not enqueued: " + node);
}
#endif
node.Priority = priority;
OnNodeUpdated(node);
}
private void OnNodeUpdated(TItem node)
{
//Bubble the updated node up or down as appropriate
int parentIndex = node.QueueIndex / 2;
var parentNode = _nodes[parentIndex];
if (parentIndex > 0 && HasHigherPriority(node, parentNode))
{
CascadeUp(node);
}
else
{
//Note that CascadeDown will be called if parentNode == node (that is, node is the root)
CascadeDown(node);
}
}
/// <summary>
/// Removes a node from the queue. The node does not need to be the head of the queue.
/// If the node is not in the queue, the result is undefined. If unsure, check Contains() first
/// O(log n)
/// </summary>
public void Remove(TItem node)
{
#if DEBUG
if (node == null)
{
throw new ArgumentNullException(nameof(node));
}
if (!Contains(node))
{
throw new InvalidOperationException("Cannot call Remove() on a node which is not enqueued: " + node);
}
#endif
//If the node is already the last node, we can remove it immediately
if (node.QueueIndex == _numNodes)
{
_nodes[_numNodes] = null;
_numNodes--;
return;
}
//Swap the node with the last node
var formerLastNode = _nodes[_numNodes];
Swap(node, formerLastNode);
_nodes[_numNodes] = null;
_numNodes--;
//Now bubble formerLastNode (which is no longer the last node) up or down as appropriate
OnNodeUpdated(formerLastNode);
}
public IEnumerator<TItem> GetEnumerator()
{
for (int i = 1; i <= _numNodes; i++)
yield return _nodes[i];
}
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
/// <summary>
/// <b>Should not be called in production code.</b>
/// Checks to make sure the queue is still in a valid state. Used for testing/debugging the queue.
/// </summary>
public bool IsValidQueue()
{
for (int i = 1; i < _nodes.Length; i++)
{
if (_nodes[i] != null)
{
int childLeftIndex = 2 * i;
if (childLeftIndex < _nodes.Length && _nodes[childLeftIndex] != null && HasHigherPriority(_nodes[childLeftIndex], _nodes[i]))
return false;
int childRightIndex = childLeftIndex + 1;
if (childRightIndex < _nodes.Length && _nodes[childRightIndex] != null && HasHigherPriority(_nodes[childRightIndex], _nodes[i]))
return false;
}
}
return true;
}
}
}

22
MediaBrowser.Providers/Manager/GenericPriorityQueueNode.cs
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namespace Priority_Queue
{
/// Credit: https://github.com/BlueRaja/High-Speed-Priority-Queue-for-C-Sharp
public class GenericPriorityQueueNode<TPriority>
{
/// <summary>
/// The Priority to insert this node at. Must be set BEFORE adding a node to the queue (ideally just once, in the node's constructor).
/// Should not be manually edited once the node has been enqueued - use queue.UpdatePriority() instead
/// </summary>
public TPriority Priority { get; protected internal set; }
/// <summary>
/// Represents the current position in the queue
/// </summary>
public int QueueIndex { get; internal set; }
/// <summary>
/// Represents the order the node was inserted in
/// </summary>
public long InsertionIndex { get; internal set; }
}
}

24
MediaBrowser.Providers/Manager/IFixedSizePriorityQueue.cs
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@ -1,24 +0,0 @@
using System;
namespace Priority_Queue
{
/// <summary>
/// Credit: https://github.com/BlueRaja/High-Speed-Priority-Queue-for-C-Sharp
/// A helper-interface only needed to make writing unit tests a bit easier (hence the 'internal' access modifier)
/// </summary>
internal interface IFixedSizePriorityQueue<TItem, in TPriority> : IPriorityQueue<TItem, TPriority>
where TPriority : IComparable<TPriority>
{
/// <summary>
/// Resize the queue so it can accept more nodes. All currently enqueued nodes are remain.
/// Attempting to decrease the queue size to a size too small to hold the existing nodes results in undefined behavior
/// </summary>
void Resize(int maxNodes);
/// <summary>
/// Returns the maximum number of items that can be enqueued at once in this queue. Once you hit this number (ie. once Count == MaxSize),
/// attempting to enqueue another item will cause undefined behavior.
/// </summary>
int MaxSize { get; }
}
}

56
MediaBrowser.Providers/Manager/IPriorityQueue.cs
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@ -1,56 +0,0 @@
using System;
using System.Collections.Generic;
namespace Priority_Queue
{
/// <summary>
/// Credit: https://github.com/BlueRaja/High-Speed-Priority-Queue-for-C-Sharp
/// The IPriorityQueue interface. This is mainly here for purists, and in case I decide to add more implementations later.
/// For speed purposes, it is actually recommended that you *don't* access the priority queue through this interface, since the JIT can
/// (theoretically?) optimize method calls from concrete-types slightly better.
/// </summary>
public interface IPriorityQueue<TItem, in TPriority> : IEnumerable<TItem>
where TPriority : IComparable<TPriority>
{
/// <summary>
/// Enqueue a node to the priority queue. Lower values are placed in front. Ties are broken by first-in-first-out.
/// See implementation for how duplicates are handled.
/// </summary>
void Enqueue(TItem node, TPriority priority);
/// <summary>
/// Removes the head of the queue (node with minimum priority; ties are broken by order of insertion), and returns it.
/// </summary>
bool TryDequeue(out TItem item);
/// <summary>
/// Removes every node from the queue.
/// </summary>
void Clear();
/// <summary>
/// Returns whether the given node is in the queue.
/// </summary>
bool Contains(TItem node);
/// <summary>
/// Removes a node from the queue. The node does not need to be the head of the queue.
/// </summary>
void Remove(TItem node);
/// <summary>
/// Call this method to change the priority of a node.
/// </summary>
void UpdatePriority(TItem node, TPriority priority);
/// <summary>
/// Returns the head of the queue, without removing it (use Dequeue() for that).
/// </summary>
TItem First { get; }
/// <summary>
/// Returns the number of nodes in the queue.
/// </summary>
int Count { get; }
}
}

247
MediaBrowser.Providers/Manager/SimplePriorityQueue.cs
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@ -1,247 +0,0 @@
using System;
using System.Collections;
using System.Collections.Generic;
namespace Priority_Queue
{
/// <summary>
/// Credit: https://github.com/BlueRaja/High-Speed-Priority-Queue-for-C-Sharp
/// A simplified priority queue implementation. Is stable, auto-resizes, and thread-safe, at the cost of being slightly slower than
/// FastPriorityQueue
/// </summary>
/// <typeparam name="TItem">The type to enqueue</typeparam>
/// <typeparam name="TPriority">The priority-type to use for nodes. Must extend IComparable&lt;TPriority&gt;</typeparam>
public class SimplePriorityQueue<TItem, TPriority> : IPriorityQueue<TItem, TPriority>
where TPriority : IComparable<TPriority>
{
private class SimpleNode : GenericPriorityQueueNode<TPriority>
{
public TItem Data { get; private set; }
public SimpleNode(TItem data)
{
Data = data;
}
}
private const int INITIAL_QUEUE_SIZE = 10;
private readonly GenericPriorityQueue<SimpleNode, TPriority> _queue;
public SimplePriorityQueue()
{
_queue = new GenericPriorityQueue<SimpleNode, TPriority>(INITIAL_QUEUE_SIZE);
}
/// <summary>
/// Given an item of type T, returns the exist SimpleNode in the queue
/// </summary>
private SimpleNode GetExistingNode(TItem item)
{
var comparer = EqualityComparer<TItem>.Default;
foreach (var node in _queue)
{
if (comparer.Equals(node.Data, item))
{
return node;
}
}
throw new InvalidOperationException("Item cannot be found in queue: " + item);
}
/// <summary>
/// Returns the number of nodes in the queue.
/// O(1)
/// </summary>
public int Count
{
get
{
lock (_queue)
{
return _queue.Count;
}
}
}
/// <summary>
/// Returns the head of the queue, without removing it (use Dequeue() for that).
/// Throws an exception when the queue is empty.
/// O(1)
/// </summary>
public TItem First
{
get
{
lock (_queue)
{
if (_queue.Count <= 0)
{
throw new InvalidOperationException("Cannot call .First on an empty queue");
}
SimpleNode first = _queue.First;
return (first != null ? first.Data : default(TItem));
}
}
}
/// <summary>
/// Removes every node from the queue.
/// O(n)
/// </summary>
public void Clear()
{
lock (_queue)
{
_queue.Clear();
}
}
/// <summary>
/// Returns whether the given item is in the queue.
/// O(n)
/// </summary>
public bool Contains(TItem item)
{
lock (_queue)
{
var comparer = EqualityComparer<TItem>.Default;
foreach (var node in _queue)
{
if (comparer.Equals(node.Data, item))
{
return true;
}
}
return false;
}
}
/// <summary>
/// Removes the head of the queue (node with minimum priority; ties are broken by order of insertion), and returns it.
/// If queue is empty, throws an exception
/// O(log n)
/// </summary>
public bool TryDequeue(out TItem item)
{
lock (_queue)
{
if (_queue.Count <= 0)
{
item = default(TItem);
return false;
}
if (_queue.TryDequeue(out SimpleNode node))
{
item = node.Data;
return true;
}
item = default(TItem);
return false;
}
}
/// <summary>
/// Enqueue a node to the priority queue. Lower values are placed in front. Ties are broken by first-in-first-out.
/// This queue automatically resizes itself, so there's no concern of the queue becoming 'full'.
/// Duplicates are allowed.
/// O(log n)
/// </summary>
public void Enqueue(TItem item, TPriority priority)
{
lock (_queue)
{
var node = new SimpleNode(item);
if (_queue.Count == _queue.MaxSize)
{
_queue.Resize(_queue.MaxSize * 2 + 1);
}
_queue.Enqueue(node, priority);
}
}
/// <summary>
/// Removes an item from the queue. The item does not need to be the head of the queue.
/// If the item is not in the queue, an exception is thrown. If unsure, check Contains() first.
/// If multiple copies of the item are enqueued, only the first one is removed.
/// O(n)
/// </summary>
public void Remove(TItem item)
{
lock (_queue)
{
try
{
_queue.Remove(GetExistingNode(item));
}
catch (InvalidOperationException ex)
{
throw new InvalidOperationException("Cannot call Remove() on a node which is not enqueued: " + item, ex);
}
}
}
/// <summary>
/// Call this method to change the priority of an item.
/// Calling this method on a item not in the queue will throw an exception.
/// If the item is enqueued multiple times, only the first one will be updated.
/// (If your requirements are complex enough that you need to enqueue the same item multiple times <i>and</i> be able
/// to update all of them, please wrap your items in a wrapper class so they can be distinguished).
/// O(n)
/// </summary>
public void UpdatePriority(TItem item, TPriority priority)
{
lock (_queue)
{
try
{
SimpleNode updateMe = GetExistingNode(item);
_queue.UpdatePriority(updateMe, priority);
}
catch (InvalidOperationException ex)
{
throw new InvalidOperationException("Cannot call UpdatePriority() on a node which is not enqueued: " + item, ex);
}
}
}
public IEnumerator<TItem> GetEnumerator()
{
var queueData = new List<TItem>();
lock (_queue)
{
//Copy to a separate list because we don't want to 'yield return' inside a lock
foreach (var node in _queue)
{
queueData.Add(node.Data);
}
}
return queueData.GetEnumerator();
}
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
public bool IsValidQueue()
{
lock (_queue)
{
return _queue.IsValidQueue();
}
}
}
/// <summary>
/// A simplified priority queue implementation. Is stable, auto-resizes, and thread-safe, at the cost of being slightly slower than
/// FastPriorityQueue
/// This class is kept here for backwards compatibility. It's recommended you use Simple
/// </summary>
/// <typeparam name="TItem">The type to enqueue</typeparam>
public class SimplePriorityQueue<TItem> : SimplePriorityQueue<TItem, float> { }
}

3
MediaBrowser.Providers/MediaBrowser.Providers.csproj
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@ -1,4 +1,4 @@
<Project Sdk="Microsoft.NET.Sdk"> <Project Sdk="Microsoft.NET.Sdk">
<ItemGroup> <ItemGroup>
<ProjectReference Include="..\MediaBrowser.Controller\MediaBrowser.Controller.csproj" /> <ProjectReference Include="..\MediaBrowser.Controller\MediaBrowser.Controller.csproj" />
@ -11,6 +11,7 @@
</ItemGroup> </ItemGroup>
<ItemGroup> <ItemGroup>
<PackageReference Include="OptimizedPriorityQueue" Version="4.2.0" />
<PackageReference Include="PlaylistsNET" Version="1.0.2" /> <PackageReference Include="PlaylistsNET" Version="1.0.2" />
</ItemGroup> </ItemGroup>