EventListenerMap.cs :  » GUI » SharpVectorGraphics » SharpVectors » Dom » Events » C# / CSharp Open Source

using System;

using SharpVectors.Dom.Events;

#if TEST
using NUnit.Framework;
#endif

namespace SharpVectors.Dom.Events{
  /// <summary>
  /// Summary description for EventListenerMap.
  /// </summary>
  public struct EventListenerMap
  {
    #region Private Fields
    
    private const int GrowthBuffer = 8;
    private const int GrowthFactor = 2;
    
    private EventListenerMapEntry[] entries;
    private int count;
    private bool locked;

    #endregion
    
    #region Private Helpers
    
    private EventListenerMapEntry[] GrowBy(
      int growth)
    {
      if (entries == null)
      {
        entries = new EventListenerMapEntry[
          growth * GrowthFactor + GrowthBuffer];
        
        this.count = 0;
        this.locked = false;
        
        return entries;
      }
      
      int newCount = count + growth;
      
      if (newCount > entries.Length)
      {
        newCount = newCount * GrowthFactor + GrowthBuffer;
        
        EventListenerMapEntry[] newEntries =
          new EventListenerMapEntry[newCount];
        
        Array.Copy(entries, 0, newEntries, 0, entries.Length);
        
        entries = newEntries;
      }
      
      return entries;
    }
    
    #endregion
    
    #region Public Methods
    
    public void AddEventListener(
      string namespaceUri,
      string eventType,
      object eventGroup,
      EventListener listener)
    {
      EventListenerMapEntry[] entries = GrowBy(1);
      
      for (int i = 0; i < count; i++)
      {
        if (namespaceUri != entries[i].NamespaceUri)
        {
          continue;
        }
        
        if (eventType != entries[i].Type)
        {
          continue;
        }
        
        if (listener == entries[i].Listener)
        {
          return;
        }
      }
      
      entries[count] = new EventListenerMapEntry(
        namespaceUri, eventType, eventGroup, listener, locked);
      
      count++;
    }
    
    public void RemoveEventListener(
      string namespaceUri,
      string eventType,
      EventListener listener)
    {
      if (entries == null)
      {
        return;
      }
      
      for (int i = 0; i < count; i++)
      {
        if (namespaceUri != entries[i].NamespaceUri)
        {
          continue;
        }
        
        if (eventType != entries[i].Type)
        {
          continue;
        }
        
        if (listener == entries[i].Listener)
        {
          count--;
          entries[i] = entries[count];
          entries[count] = new EventListenerMapEntry();
          
          return;
        }
      }
    }
    
    public void FireEvent(
      IEvent @event)
    {
      string namespaceUri = @event.NamespaceUri;
      string eventType = @event.Type;
      for (int i = 0; i < count; i++)
      {
        // Check if the entry was added during this phase
        if (entries[i].Locked)
          continue;

        string entryNamespaceUri = entries[i].NamespaceUri;
        string entryEventType = entries[i].Type;        

        if (entryNamespaceUri != null && namespaceUri != null)
        {
          if (entryNamespaceUri != namespaceUri)
          {
            continue;
          }
        }
        
        if (entryEventType != eventType)
        {
          continue;
        }
        
        entries[i].Listener(@event);
      }
    }
    
    public bool HasEventListenerNs(
      string namespaceUri,
      string eventType)
    {
      if (entries == null)
      {
        return false;
      }
      
      for (int i = 0; i < count; i++)
      {
        if (namespaceUri != entries[i].NamespaceUri)
        {
          continue;
        }
        
        if (eventType != entries[i].Type)
        {
          continue;
        }
        
        return true;
      }
      
      return false;
    }
    
    public void Lock() 
    {
      locked = true;
    }

    public void Unlock() 
    {
      // Unlock the map
      locked = false;

      // Unlock pending entries
      for (int i = 0; i < count; i++)
      {
        entries[i].Locked = false;        
      }
    }
    #endregion
  }
}