Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Core / CSharp / System / Windows / Media / ChannelManager.cs / 1305600 / ChannelManager.cs
//------------------------------------------------------------------------------
//
//
// Copyright (C) Microsoft Corporation. All rights reserved.
//
//
// Description:
// The ChannelManager is a helper structure internal to MediaContext
// that abstracts out channel creation, storage and destruction.
//
//-----------------------------------------------------------------------------
using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;
using System.Windows.Threading;
using System.Windows;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Media.Composition;
using System.Security;
using MS.Internal;
using MS.Utility;
using MS.Win32;
using Microsoft.Win32.SafeHandles;
using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID;
using UnsafeNativeMethods=MS.Win32.PresentationCore.UnsafeNativeMethods.MilCoreApi;
namespace System.Windows.Media
{
partial class MediaContext
{
///
/// A helper structure that abstracts channel management.
///
///
/// The common agreement (avcomptm, avpttrev) is that channel creation
/// should be considered unsafe and therefore subject to control via
/// the SecurityCritical/SecurityTreatAsSafe mechanism.
///
/// On the other hand, using a channel that has been created by the
/// MediaContext is considered safe.
///
/// This class expresses the above policy by hiding channel creation
/// and storage within the MediaContext while allowing to access
/// the channels at will.
///
private struct ChannelManager
{
///
/// Opens an asynchronous channel.
///
///
/// Critical - Creates a channel, calls a Channel method, calls methods performing elevations.
/// TreatAsSafe - It is safe for the media context to create and use a channel.
///
[SecurityCritical, SecurityTreatAsSafe]
internal void CreateChannels()
{
Invariant.Assert(_asyncChannel == null);
Invariant.Assert(_asyncOutOfBandChannel == null);
// Create a channel into the async composition device.
// Pass in a reference to the global mediasystem channel so that it uses
// the same partition.
_asyncChannel = new DUCE.Channel(
System.Windows.Media.MediaSystem.ServiceChannel,
false, // not out of band
System.Windows.Media.MediaSystem.Connection,
false // [....] transport
);
_asyncOutOfBandChannel = new DUCE.Channel(
System.Windows.Media.MediaSystem.ServiceChannel,
true, // out of band
System.Windows.Media.MediaSystem.Connection,
false // [....] transport
);
}
///
/// Closes all opened channels.
///
///
/// Critical - Closes channels.
/// TreatAsSafe - It is safe for the media context to [....] channels channel.
///
[SecurityCritical, SecurityTreatAsSafe]
internal void RemoveSyncChannels()
{
//
// Close the synchronous channels.
//
if (_freeSyncChannels != null)
{
while (_freeSyncChannels.Count > 0)
{
_freeSyncChannels.Dequeue().Close();
}
_freeSyncChannels = null;
}
if (_syncServiceChannel != null)
{
_syncServiceChannel.Close();
_syncServiceChannel = null;
}
}
///
/// Closes all opened channels.
///
///
/// Critical - Closes channels.
/// TreatAsSafe - It is safe for the media context to close a channel.
///
[SecurityCritical, SecurityTreatAsSafe]
internal void RemoveChannels()
{
if (_asyncChannel != null)
{
_asyncChannel.Close();
_asyncChannel = null;
}
if (_asyncOutOfBandChannel != null)
{
_asyncOutOfBandChannel.Close();
_asyncOutOfBandChannel = null;
}
RemoveSyncChannels();
if (_pSyncConnection != IntPtr.Zero)
{
HRESULT.Check(UnsafeNativeMethods.WgxConnection_Disconnect(_pSyncConnection));
_pSyncConnection = IntPtr.Zero;
}
}
///
/// Create a fresh or fetch one from the pool synchronous channel.
///
///
/// Critical - Calls critical methods to create a synchronous channel and return it.
/// TreatAsSafe - This function allocates the channel in a Channel class that guards channel
/// access from insecure access. It is also ok for this method to allocate the native objects
/// since there is nothing security critical about having the channel infrastructure initialized.
///
[SecurityCritical, SecurityTreatAsSafe]
internal DUCE.Channel AllocateSyncChannel()
{
DUCE.Channel syncChannel;
if (_pSyncConnection == IntPtr.Zero)
{
HRESULT.Check(UnsafeNativeMethods.WgxConnection_Create(
true, // true means synchronous transport
out _pSyncConnection));
}
if (_freeSyncChannels == null)
{
//
// Ensure the free [....] channels queue...
//
_freeSyncChannels = new Queue(3);
}
if (_freeSyncChannels.Count > 0)
{
//
// If there is a free [....] channel in the queue, we're done:
//
return _freeSyncChannels.Dequeue();
}
else
{
//
// Otherwise, create a new channel. We will try to cache it
// when the ReleaseSyncChannel call is made. Also ensure the
// synchronous service channel and glyph cache.
//
if (_syncServiceChannel == null)
{
_syncServiceChannel = new DUCE.Channel(
null,
false, // not out of band
_pSyncConnection,
true // synchronous
);
}
syncChannel = new DUCE.Channel(
_syncServiceChannel,
false, // not out of band
_pSyncConnection,
true // synchronous
);
return syncChannel;
}
}
///
/// Returns a [....] channel back to the pool.
///
///
/// Critical - Creates and returns a synchronous channel.
/// TreatAsSafe - Closing a channel is safe.
///
[SecurityCritical, SecurityTreatAsSafe]
internal void ReleaseSyncChannel(DUCE.Channel channel)
{
Invariant.Assert(_freeSyncChannels != null);
//
// A decision needs to be made whether or not we're interested
// in re-using this channel later. For now, store up to three
// synchronous channel in the queue.
//
if (_freeSyncChannels.Count <= 3)
{
_freeSyncChannels.Enqueue(channel);
}
else
{
channel.Close();
}
}
///
/// Returns the asynchronous channel.
///
///
/// Critical - Channels are a controlled unmanaged resource.
/// TreatAsSafe - Using a channel created by the media context is safe.
///
internal DUCE.Channel Channel
{
[SecurityCritical, SecurityTreatAsSafe]
get
{
return _asyncChannel;
}
}
///
/// Returns the asynchronous out-of-band channel.
///
///
/// Critical - Channels are a controlled unmanaged resource.
/// TreatAsSafe - Using a channel created by the media context is safe.
///
internal DUCE.Channel OutOfBandChannel
{
[SecurityCritical, SecurityTreatAsSafe]
get
{
return _asyncOutOfBandChannel;
}
}
///
/// The asynchronous channel.
///
///
/// This field will be replaced with an asynchronous channel table as per task #26681.
///
///
/// Critical - Channels are a controlled unmanaged resource.
///
[SecurityCritical]
private DUCE.Channel _asyncChannel;
///
/// The asynchronous out-of-band channel.
///
///
/// This is needed by CompositionTarget for handling WM_PAINT, etc.
///
///
/// Critical - Channels are a controlled unmanaged resource.
///
[SecurityCritical]
private DUCE.Channel _asyncOutOfBandChannel;
///
/// We store the free synchronous channels for later re-use in this queue.
///
///
/// Critical - Channels are a controlled unmanaged resource.
///
[SecurityCritical]
private Queue _freeSyncChannels;
///
/// The service channel to the synchronous partition.
///
///
/// Critical - Channels are a controlled unmanaged resource.
///
[SecurityCritical]
private DUCE.Channel _syncServiceChannel;
///
/// Pointer to the unmanaged connection object.
///
///
/// Critical - Controlled unmanaged resource.
///
[SecurityCritical]
private IntPtr _pSyncConnection;
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
//------------------------------------------------------------------------------
//
//
// Copyright (C) Microsoft Corporation. All rights reserved.
//
//
// Description:
// The ChannelManager is a helper structure internal to MediaContext
// that abstracts out channel creation, storage and destruction.
//
//-----------------------------------------------------------------------------
using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;
using System.Windows.Threading;
using System.Windows;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Media.Composition;
using System.Security;
using MS.Internal;
using MS.Utility;
using MS.Win32;
using Microsoft.Win32.SafeHandles;
using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID;
using UnsafeNativeMethods=MS.Win32.PresentationCore.UnsafeNativeMethods.MilCoreApi;
namespace System.Windows.Media
{
partial class MediaContext
{
///
/// A helper structure that abstracts channel management.
///
///
/// The common agreement (avcomptm, avpttrev) is that channel creation
/// should be considered unsafe and therefore subject to control via
/// the SecurityCritical/SecurityTreatAsSafe mechanism.
///
/// On the other hand, using a channel that has been created by the
/// MediaContext is considered safe.
///
/// This class expresses the above policy by hiding channel creation
/// and storage within the MediaContext while allowing to access
/// the channels at will.
///
private struct ChannelManager
{
///
/// Opens an asynchronous channel.
///
///
/// Critical - Creates a channel, calls a Channel method, calls methods performing elevations.
/// TreatAsSafe - It is safe for the media context to create and use a channel.
///
[SecurityCritical, SecurityTreatAsSafe]
internal void CreateChannels()
{
Invariant.Assert(_asyncChannel == null);
Invariant.Assert(_asyncOutOfBandChannel == null);
// Create a channel into the async composition device.
// Pass in a reference to the global mediasystem channel so that it uses
// the same partition.
_asyncChannel = new DUCE.Channel(
System.Windows.Media.MediaSystem.ServiceChannel,
false, // not out of band
System.Windows.Media.MediaSystem.Connection,
false // [....] transport
);
_asyncOutOfBandChannel = new DUCE.Channel(
System.Windows.Media.MediaSystem.ServiceChannel,
true, // out of band
System.Windows.Media.MediaSystem.Connection,
false // [....] transport
);
}
///
/// Closes all opened channels.
///
///
/// Critical - Closes channels.
/// TreatAsSafe - It is safe for the media context to [....] channels channel.
///
[SecurityCritical, SecurityTreatAsSafe]
internal void RemoveSyncChannels()
{
//
// Close the synchronous channels.
//
if (_freeSyncChannels != null)
{
while (_freeSyncChannels.Count > 0)
{
_freeSyncChannels.Dequeue().Close();
}
_freeSyncChannels = null;
}
if (_syncServiceChannel != null)
{
_syncServiceChannel.Close();
_syncServiceChannel = null;
}
}
///
/// Closes all opened channels.
///
///
/// Critical - Closes channels.
/// TreatAsSafe - It is safe for the media context to close a channel.
///
[SecurityCritical, SecurityTreatAsSafe]
internal void RemoveChannels()
{
if (_asyncChannel != null)
{
_asyncChannel.Close();
_asyncChannel = null;
}
if (_asyncOutOfBandChannel != null)
{
_asyncOutOfBandChannel.Close();
_asyncOutOfBandChannel = null;
}
RemoveSyncChannels();
if (_pSyncConnection != IntPtr.Zero)
{
HRESULT.Check(UnsafeNativeMethods.WgxConnection_Disconnect(_pSyncConnection));
_pSyncConnection = IntPtr.Zero;
}
}
///
/// Create a fresh or fetch one from the pool synchronous channel.
///
///
/// Critical - Calls critical methods to create a synchronous channel and return it.
/// TreatAsSafe - This function allocates the channel in a Channel class that guards channel
/// access from insecure access. It is also ok for this method to allocate the native objects
/// since there is nothing security critical about having the channel infrastructure initialized.
///
[SecurityCritical, SecurityTreatAsSafe]
internal DUCE.Channel AllocateSyncChannel()
{
DUCE.Channel syncChannel;
if (_pSyncConnection == IntPtr.Zero)
{
HRESULT.Check(UnsafeNativeMethods.WgxConnection_Create(
true, // true means synchronous transport
out _pSyncConnection));
}
if (_freeSyncChannels == null)
{
//
// Ensure the free [....] channels queue...
//
_freeSyncChannels = new Queue(3);
}
if (_freeSyncChannels.Count > 0)
{
//
// If there is a free [....] channel in the queue, we're done:
//
return _freeSyncChannels.Dequeue();
}
else
{
//
// Otherwise, create a new channel. We will try to cache it
// when the ReleaseSyncChannel call is made. Also ensure the
// synchronous service channel and glyph cache.
//
if (_syncServiceChannel == null)
{
_syncServiceChannel = new DUCE.Channel(
null,
false, // not out of band
_pSyncConnection,
true // synchronous
);
}
syncChannel = new DUCE.Channel(
_syncServiceChannel,
false, // not out of band
_pSyncConnection,
true // synchronous
);
return syncChannel;
}
}
///
/// Returns a [....] channel back to the pool.
///
///
/// Critical - Creates and returns a synchronous channel.
/// TreatAsSafe - Closing a channel is safe.
///
[SecurityCritical, SecurityTreatAsSafe]
internal void ReleaseSyncChannel(DUCE.Channel channel)
{
Invariant.Assert(_freeSyncChannels != null);
//
// A decision needs to be made whether or not we're interested
// in re-using this channel later. For now, store up to three
// synchronous channel in the queue.
//
if (_freeSyncChannels.Count <= 3)
{
_freeSyncChannels.Enqueue(channel);
}
else
{
channel.Close();
}
}
///
/// Returns the asynchronous channel.
///
///
/// Critical - Channels are a controlled unmanaged resource.
/// TreatAsSafe - Using a channel created by the media context is safe.
///
internal DUCE.Channel Channel
{
[SecurityCritical, SecurityTreatAsSafe]
get
{
return _asyncChannel;
}
}
///
/// Returns the asynchronous out-of-band channel.
///
///
/// Critical - Channels are a controlled unmanaged resource.
/// TreatAsSafe - Using a channel created by the media context is safe.
///
internal DUCE.Channel OutOfBandChannel
{
[SecurityCritical, SecurityTreatAsSafe]
get
{
return _asyncOutOfBandChannel;
}
}
///
/// The asynchronous channel.
///
///
/// This field will be replaced with an asynchronous channel table as per task #26681.
///
///
/// Critical - Channels are a controlled unmanaged resource.
///
[SecurityCritical]
private DUCE.Channel _asyncChannel;
///
/// The asynchronous out-of-band channel.
///
///
/// This is needed by CompositionTarget for handling WM_PAINT, etc.
///
///
/// Critical - Channels are a controlled unmanaged resource.
///
[SecurityCritical]
private DUCE.Channel _asyncOutOfBandChannel;
///
/// We store the free synchronous channels for later re-use in this queue.
///
///
/// Critical - Channels are a controlled unmanaged resource.
///
[SecurityCritical]
private Queue _freeSyncChannels;
///
/// The service channel to the synchronous partition.
///
///
/// Critical - Channels are a controlled unmanaged resource.
///
[SecurityCritical]
private DUCE.Channel _syncServiceChannel;
///
/// Pointer to the unmanaged connection object.
///
///
/// Critical - Controlled unmanaged resource.
///
[SecurityCritical]
private IntPtr _pSyncConnection;
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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