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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
/***************************************************************************\
*
*
* A SoundPlayerAction causes a sound to be played in response to a trigger.
*
*
\***************************************************************************/
using MS.Internal;
using System.ComponentModel; // DefaultValueAttribute
using System.IO;
using System.Media;
using System.Windows.Navigation;
using System.Windows.Threading;
using System.Threading.Tasks;
namespace System.Windows.Controls
{
/// <summary>
/// A class that describes a sound playback action to perform for a trigger
/// </summary>
public class SoundPlayerAction : TriggerAction, IDisposable
{
/// <summary>
/// Creates an instance of the SoundPlayerAction object.
/// </summary>
public SoundPlayerAction()
: base()
{
}
/// <summary>
/// Dispose.
/// </summary>
public void Dispose()
{
if (m_player != null)
{
m_player.Dispose();
}
}
/// <summary>
/// DependencyProperty for Source
/// </summary>
public static readonly DependencyProperty SourceProperty =
DependencyProperty.Register(
"Source",
typeof(Uri),
typeof(SoundPlayerAction),
new FrameworkPropertyMetadata(
new PropertyChangedCallback(OnSourceChanged)));
/// <summary>
/// A class that describes a sound playback action to perform for a trigger
/// </summary>
public Uri Source
{
get { return (Uri)GetValue(SourceProperty); }
set { SetValue(SourceProperty, value); }
}
private static void OnSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
SoundPlayerAction soundPlayerAction = (SoundPlayerAction)d;
soundPlayerAction.OnSourceChangedHelper((Uri)e.NewValue);
}
// To avoid blocking the UI thread, SoundPlayerAction performs an asynchronous
// download of the WebResponse and later, the response Stream. However,
// PackWebRequest does not support the asynchonous Begin/EndGetResponse pattern.
// To work around this, we use our own asynchronous worker pool thread,
// and then use the regular synchronous WebRequest.GetResponse() method.
// Once we obtain the WebResponse, we will use SoundPlayer's async API
// to download the content of the stream.
private void OnSourceChangedHelper(Uri newValue)
{
if (newValue == null || newValue.IsAbsoluteUri)
{
m_lastRequestedAbsoluteUri = newValue;
}
else
{
// When we are given a relative Uri path, expand to an absolute Uri by resolving
// it against the Application's base Uri. This would typically return a Pack Uri.
m_lastRequestedAbsoluteUri =
BaseUriHelper.GetResolvedUri(BaseUriHelper.BaseUri, newValue);
}
// Invalidate items that depend on the Source uri
m_player = null;
m_playRequested = false; // Suppress earlier requests to Play the sound
if (m_streamLoadInProgress)
{
// There is already a worker thread downloading the previous URI stream,
// or the SoundPlayer is copying the stream into its buffer. Make a note
// that the URI has been changed and we will have to reload everything.
m_uriChangedWhileLoadingStream = true;
}
else
{
BeginLoadStream();
}
}
/// <summary>
/// Invoke the SoundPlayer action.
/// </summary>
internal sealed override void Invoke(FrameworkElement el,
FrameworkContentElement ctntEl,
Style targetStyle,
FrameworkTemplate targetTemplate,
Int64 layer)
{
PlayWhenLoaded();
}
/// <summary>
/// invoke the SoundPlayer action.
/// </summary>
internal sealed override void Invoke(FrameworkElement el)
{
PlayWhenLoaded();
}
/// <summary>
/// Plays the
/// </summary>
private void PlayWhenLoaded()
{
if (m_streamLoadInProgress)
{
m_playRequested = true;
}
else if (m_player != null)
{
// If the Player has not yet loaded, m_streamLoadInProgress must be true
Debug.Assert(m_player.IsLoadCompleted);
m_player.Play();
}
}
private void BeginLoadStream()
{
if (m_lastRequestedAbsoluteUri != null) // Only reload if the new source is non-null
{
m_streamLoadInProgress = true;
// Step 1: Perform an asynchronous load of the WebResponse and its associated Stream
Task.Run(() =>
{
Stream result = WpfWebRequestHelper.CreateRequestAndGetResponseStream(m_lastRequestedAbsoluteUri);
LoadStreamCallback(result);
});
}
}
private delegate Stream LoadStreamCaller(Uri uri);
/// <summary>
/// This is the actual code that runs in our worker thread.
/// </summary>
private Stream LoadStreamAsync(Uri uri)
{
return WpfWebRequestHelper.CreateRequestAndGetResponseStream(uri);
}
/// <summary>
/// This code runs in the worker thread when LoadStreamAsync() finishes.
/// </summary>
/// <param name="asyncResult"></param>
private void LoadStreamCallback(Stream asyncResult)
{
// Now have the UI thread regain control and initialize the SoundPlayer
DispatcherOperationCallback loadStreamCompletedCaller = new DispatcherOperationCallback(OnLoadStreamCompleted);
Dispatcher.BeginInvoke(DispatcherPriority.Normal, loadStreamCompletedCaller, asyncResult);
}
/// <summary>
/// Called on the UI thread when the Stream object is initialized.
/// Begins asynchronous download of the Stream content into SoundPlayer's local buffer.
/// </summary>
private Object OnLoadStreamCompleted(Object asyncResultArg)
{
Stream newStream = (Stream)asyncResultArg;
if (m_uriChangedWhileLoadingStream) // The source URI was changed, redo Stream loading
{
m_uriChangedWhileLoadingStream = false;
if (newStream != null) // Don't hold on to the new stream - it's not needed anymore
{
newStream.Dispose();
}
BeginLoadStream();
}
else if (newStream != null) // We loaded the Stream, begin buffering it
{
if (m_player == null)
{
m_player = new SoundPlayer((Stream)newStream);
}
else
{
m_player.Stream = (Stream)newStream;
}
m_player.LoadCompleted += new AsyncCompletedEventHandler(OnSoundPlayerLoadCompleted);
m_player.LoadAsync(); // Begin preloading the stream into SoundPlayer's local buffer
}
return null;
}
private void OnSoundPlayerLoadCompleted(Object sender, AsyncCompletedEventArgs e)
{
if (Object.ReferenceEquals(m_player, sender))
{
Debug.Assert(m_player.IsLoadCompleted);
if (m_uriChangedWhileLoadingStream) // The source URI was changed, redo Stream loading again
{
m_player = null;
m_uriChangedWhileLoadingStream = false;
BeginLoadStream();
}
else
{
m_streamLoadInProgress = false;
if (m_playRequested) // URI is correct, m_player is ready, play it if requested
{
m_playRequested = false;
m_player.Play();
}
}
}
}
private SoundPlayer m_player;
private Uri m_lastRequestedAbsoluteUri;
private bool m_streamLoadInProgress;
private bool m_playRequested;
private bool m_uriChangedWhileLoadingStream;
}
}
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