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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.
using MS.Internal.Documents;
//
// Description:
// Represent a node in the doubly linked list a DocumentSequenceTextContainer
// maintains for the child-TextContainers it aggregates. Each child-TextContainer
// would have a corresponding entry in the list.
//
namespace System.Windows.Documents
{
//=====================================================================
/// <summary>
/// Represent a node in the doubly linked list a DocumentSequenceTextContainer
/// maintains for the child-TextContainers it aggregates. Each child-TextContainer
/// would have a corresponding entry in the list.
/// </summary>
internal sealed class ChildDocumentBlock
{
//--------------------------------------------------------------------
//
// Enum
//
//---------------------------------------------------------------------
[Flags()]
internal enum BlockStatus
{
None = 0,
UnloadedBlock = 1, // Child block has not been loaded
}
//--------------------------------------------------------------------
//
// Connstructors
//
//---------------------------------------------------------------------
#region Ctors
internal ChildDocumentBlock(DocumentSequenceTextContainer aggregatedContainer, ITextContainer childContainer)
{
Debug.Assert(childContainer != null);
_aggregatedContainer = aggregatedContainer;
_container = childContainer;
}
internal ChildDocumentBlock(DocumentSequenceTextContainer aggregatedContainer, DocumentReference docRef)
{
Debug.Assert(docRef != null);
_aggregatedContainer = aggregatedContainer;
_docRef = docRef;
_SetStatus(BlockStatus.UnloadedBlock);
}
#endregion Ctors
//--------------------------------------------------------------------
//
// Internal Properties
//
//---------------------------------------------------------------------
#region Internal Methods
// Insert a new node into this list.
internal ChildDocumentBlock InsertNextBlock(ChildDocumentBlock newBlock)
{
Debug.Assert(newBlock != null);
// Setup the new block correctly
newBlock._nextBlock = this._nextBlock;
newBlock._previousBlock = this;
// Link old next block to the new block
if (this._nextBlock != null)
{
this._nextBlock._previousBlock = newBlock;
}
// Link this block to new block
this._nextBlock = newBlock;
return newBlock;
}
#endregion Internal Methods
//--------------------------------------------------------------------
//
// Internal Properties
//
//---------------------------------------------------------------------
#region Internal Properties
// The AggregatedContainer that holds the list of ChildDocumentBlock.
internal DocumentSequenceTextContainer AggregatedContainer
{
get
{
return _aggregatedContainer;
}
}
// Reference to the child TextContainer
internal ITextContainer ChildContainer
{
get
{
_EnsureBlockLoaded();
return _container;
}
}
// The highlight layer used to notify child TextContainer
// about TextSelection highlight change.
internal DocumentSequenceHighlightLayer ChildHighlightLayer
{
get
{
if (_highlightLayer == null)
{
_highlightLayer = new DocumentSequenceHighlightLayer(_aggregatedContainer);
Debug.Assert(ChildContainer.Highlights.GetLayer(typeof(TextSelection)) == null);
ChildContainer.Highlights.AddLayer(_highlightLayer);
}
return _highlightLayer;
}
}
// Reference to the DocumentReference
internal DocumentReference DocRef
{
get
{
return _docRef;
}
}
// End TextPointer of the child container
internal ITextPointer End
{
get
{
return ChildContainer.End;
}
}
#if DEBUG
// Get if this entry is non-head/tail block in the linked list
internal bool IsInsideBlock
{
get
{
return (this._previousBlock != null && this._nextBlock != null);
}
}
#endif
// Get if this entry is Head of list
internal bool IsHead
{
get
{
return (this._previousBlock == null);
}
}
// Get if this entry is Tail of list
internal bool IsTail
{
get
{
return (this._nextBlock == null);
}
}
// Previous container entry in the link list
internal ChildDocumentBlock PreviousBlock
{
get
{
return _previousBlock;
}
}
// Next container entry in the link list
internal ChildDocumentBlock NextBlock
{
get
{
return _nextBlock;
}
}
#if DEBUG
internal uint DebugId
{
get
{
return _debugId;
}
}
#endif
#endregion Internal Properties
//--------------------------------------------------------------------
//
// Private Methods
//
//---------------------------------------------------------------------
#region Private Methods
private void _EnsureBlockLoaded()
{
if (_HasStatus(BlockStatus.UnloadedBlock))
{
_ClearStatus(BlockStatus.UnloadedBlock);
DocumentsTrace.FixedDocumentSequence.TextOM.Trace($"Loading TextContainer {_docRef}");
// Load the TextContainer
IDocumentPaginatorSource idp = _docRef.GetDocument(false /*forceReload*/);
IServiceProvider isp = idp as IServiceProvider;
if (isp != null)
{
ITextContainer tc = isp.GetService(typeof(ITextContainer)) as ITextContainer;
if (tc != null)
{
_container = tc;
DocumentsTrace.FixedDocumentSequence.TextOM.Trace("Got ITextContainer");
}
}
if (_container == null)
{
_container = new NullTextContainer();
}
}
}
private bool _HasStatus(BlockStatus flags)
{
return ((_status & flags) == flags);
}
private void _SetStatus(BlockStatus flags)
{
_status |= flags;
}
private void _ClearStatus(BlockStatus flags)
{
_status &= (~flags);
}
#endregion Private Methods
//--------------------------------------------------------------------
//
// Private Fields
//
//---------------------------------------------------------------------
#region Private Fields
private readonly DocumentSequenceTextContainer _aggregatedContainer;
private readonly DocumentReference _docRef; // Reference to the sub-document
private ITextContainer _container; // Child TextContainer
private DocumentSequenceHighlightLayer _highlightLayer; // Highlight layer used to notify child TextContainer highlight changes.
private BlockStatus _status; // Status of this block, such as Loaded, etc.
private ChildDocumentBlock _previousBlock; // Link to previous block
private ChildDocumentBlock _nextBlock; // Link to next block
#if DEBUG
private uint _debugId = (_debugIdCounter++);
private static uint _debugIdCounter = 0;
#endif
#endregion Private Fields
}
}
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