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/***************************************************************************\
*
* File: TreeBuilder.cs
*
* Purpose: Class that builds a stream from XAML or BAML and handles
*
* History:
* 6/06/01: rogerg Created
* 5/28/03: peterost Ported to wcp
*
* Copyright (C) 2002 by Microsoft Corporation. All rights reserved.
*
\***************************************************************************/
using System;
using System.Xml;
using System.IO;
using System.Text;
using System.Collections;
using System.ComponentModel;
using System.Diagnostics;
using System.Reflection;
using System.Runtime.InteropServices;
using MS.Utility;
#if PBTCOMPILER
namespace MS.Internal.Markup
#else
using System.Windows;
using System.Windows.Threading;
namespace System.Windows.Markup
#endif
{
/// <summary>
/// internal base class that acts as the Traffic cop for reading BAMl and XMAL.
/// The XamlTreeBuilder and TreeBuilderBamlTranslator class override this class for each
/// of there implementations.
/// </summary>
internal abstract class TreeBuilder
{
#region Constructors
/// <summary>
/// Constructor
/// </summary>
public TreeBuilder()
{
}
#endregion Constructors
#region Methods
#if !PBTCOMPILER
/// <summary>
/// Internal Avalon method. Used to load the file. Does not allow multiple roots.
/// </summary>
/// <returns>The root of the loaded file</returns>
public object Parse ()
{
// if there is a BamlRecordReader setup the inherited Properties
Debug.Assert (null != RecordReader, "No BamlRecordReader at Parse() time");
object root = ParseFragment ();
// If the root is a DependencyObject, then store the XamlTypeMapper's xmlns hashtable on
// it so that it can be used for runtime lookups of xaml namespace prefixes. Make
// sure to enter the context associated with the root, since the context may change
// for async parse cases
if (root is DependencyObject && !RecordReader.IsRootAlreadyLoaded)
{
((DependencyObject)root).SetValue(XmlAttributeProperties.XmlNamespaceMapsProperty,
RecordReader.XamlTypeMapper.NamespaceMapHashList);
}
// Or, if the root is a MarupExtension, we need to convert it into it's final value.
else if( root is MarkupExtension )
{
root = (root as MarkupExtension).ProvideValue(null);
}
return root;
}
#endif
/// <summary>
/// Internal Avalon method. Used to Load a file.
/// </summary>
/// <returns>An array containing the root objects Loaded from the stream stream</returns>
public virtual object ParseFragment ()
{
Debug.Assert (false, "Parse Fragment was not overidden");
return null;
}
#if !PBTCOMPILER // No async support for compilation
/// <summary>
/// called when in async mode when get a time slice to read and load the Tree
/// </summary>
internal virtual void HandleAsyncQueueItem ()
{
Debug.Assert (false == RecordReader.EndOfDocument); // shouldn't be called after end
try
{
int startTickCount = MS.Win32.SafeNativeMethods.GetTickCount();
bool moreData = true;
// It is possible that we have encountered an exception while parsing/loading
// the root element which would have happened prior to this. Hence the additional checks.
if (!_parseStarted && !RecordReader.EndOfDocument && !ParseError && !ParseCancelled)
{
if(RecordReader.BytesAvailible < BamlVersionHeader.BinarySerializationSize)
{
return;
}
RecordReader.ReadVersionHeader();
_parseStarted = true;
}
// for debugging, can set the Maximum Async records to
// read via markup
// x:AsyncRecords="3" would loop three times
// Todo: This should either be removed at some point
int maxRecords = MaxAsyncRecords;
// while there is moreData and not at the end of document.
while (moreData && !RecordReader.EndOfDocument && !ParseError && !ParseCancelled)
{
moreData = RecordReader.Read (true /* single record mode*/);
//Debug.Assert (1 >= RootList.Count, "Multiple roots not supported in async mode");
// check the timeout
int elapsed = MS.Win32.SafeNativeMethods.GetTickCount() - startTickCount;
// check for rollover
if (elapsed < 0)
{
startTickCount = 0; // reset to 0,
}
else if (elapsed > AsyncLoopTimeout)
{
break;
}
// decrement and compare with zero so the unitialized -1 and zero case
// doesn't break the loop.
if (--maxRecords == 0)
{
break;
}
}
}
catch (XamlParseException e)
{
ParseException = e;
}
finally
{
if (ParseError || ParseCancelled)
{
Debug.Assert (ParseError == (null != ParseException), "ParseError flag and ParseException must match up");
TreeBuildComplete();
}
else
{
// if not at the EndOfDocument then post another work item
if (false == RecordReader.EndOfDocument)
{
Post ();
}
else
{
// Building of the Tree is complete.
TreeBuildComplete ();
}
}
}
}
#endif
/// <summary>
/// Called when Tree has been completely built.
/// </summary>
internal virtual void TreeBuildComplete ()
{
}
#endregion Methods
#region Properties
#if !PBTCOMPILER
/// <summary>
/// ParserHooks implementation
/// </summary>
internal ParserHooks ParserHooks
{
get { return _hooks; }
set { _hooks = value; }
}
/// <summary>
/// Root element
/// </summary>
internal object GetRoot()
{
ArrayList roots = RecordReader.RootList;
object root = (null == roots || 0 == roots.Count) ? null : roots[0];
if (root != null && roots.Count > 1)
{
throw new XamlParseException(SR.Get(SRID.ParserMultiRoot));
}
return root;
}
/// <summary>
/// BamlRecordReader used for Loading the Tree
/// </summary>
internal BamlRecordReader RecordReader
{
get { return _bamlRecordReader; }
set { _bamlRecordReader = value; }
}
#endif
#if !PBTCOMPILER
/// <summary>
/// Mode we are loading the file in Sync, Async
/// </summary>
internal XamlParseMode XamlParseMode
{
get { return _xamlParseMode; }
set { _xamlParseMode = value; }
}
/// <summary>
/// Maximum amount of records allowed to read within
/// a HandleAsync call
/// </summary>
internal int MaxAsyncRecords
{
get { return _maxAsyncRecords; }
set { _maxAsyncRecords = value; }
}
/// <summary>
/// flag to indicate a ParseError occured
/// </summary>
internal bool ParseError
{
get { return _parseException != null; }
}
/// <summary>
/// Exception that caused the Parse Error
/// </summary>
internal Exception ParseException
{
get { return _parseException; }
set { _parseException = value; }
}
/// <summary>
/// Flag to indicate that the Parse was Cancelled before the tree was
/// completely loaded.
/// </summary>
internal bool ParseCancelled
{
get { return _parseCancelled; }
set { _parseCancelled = value; }
}
#endif
#endregion Properties
#region Queuing
#if !PBTCOMPILER
/// <summary>
/// Post a queue item at default priority
/// </summary>
internal void Post ()
{
Post (DispatcherPriority.Background);
}
/// <summary>
/// Post a queue item at the specified priority
/// </summary>
internal void Post (DispatcherPriority priority)
{
DispatcherOperationCallback callback = new DispatcherOperationCallback (Dispatch);
Dispatcher.CurrentDispatcher.BeginInvoke(priority, callback, this);
}
/// <summary>
/// Dispatch delegate
/// </summary>
private object Dispatch (object o)
{
DispatchParserQueueEvent ((TreeBuilder)o);
return null;
}
private void DispatchParserQueueEvent (TreeBuilder treeBuilder)
{
treeBuilder.HandleAsyncQueueItem ();
}
#endif
#endregion Queuing
#region Data
//
const int AsyncLoopTimeout = (int)200;
#if !PBTCOMPILER
BamlRecordReader _bamlRecordReader;
XamlParseMode _xamlParseMode;
ParserHooks _hooks;
bool _parseCancelled;
bool _parseStarted;
Exception _parseException;
int _maxAsyncRecords;
#endif
#endregion Data
}
}
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