RegionIterator.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Data / System / NewXml / RegionIterator.cs / 1305376 / RegionIterator.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
// [....]
//----------------------------------------------------------------------------- 
#pragma warning disable 618 // ignore obsolete warning about XmlDataDocument 
namespace System.Xml {
    using System; 
    using System.Diagnostics;
    using System.Text;

 
    internal abstract class BaseRegionIterator : BaseTreeIterator {
        internal BaseRegionIterator( DataSetMapper mapper ) : base( mapper ) { 
        } 

    } 


    // Iterates over non-attribute nodes
    internal sealed class RegionIterator : BaseRegionIterator { 
        private XmlBoundElement rowElement;
        private XmlNode         currentNode; 
 
        internal RegionIterator( XmlBoundElement rowElement ) : base( ((XmlDataDocument)(rowElement.OwnerDocument)).Mapper ) {
            Debug.Assert( rowElement != null && rowElement.Row != null ); 
            this.rowElement  = rowElement;
            this.currentNode = rowElement;
        }
 
        internal override void Reset() {
            currentNode = rowElement; 
        } 

        internal override XmlNode CurrentNode { 
            get {
                return currentNode;
            }
        } 

        internal override bool Next() { 
            XmlNode nextNode; 
            ElementState oldState = rowElement.ElementState;
            // We do not want to cause any foliation w/ this iterator or use this iterator once the region was defoliated 
            Debug.Assert( oldState != ElementState.None );

            // Try to move to the first child
            nextNode = currentNode.FirstChild; 

            // No children, try next sibling 
            if ( nextNode != null ) { 
                currentNode = nextNode;
                // If we have been defoliated, we should have stayed that way 
                Debug.Assert( (oldState == ElementState.Defoliated) ? (rowElement.ElementState == ElementState.Defoliated) : true );
                // Rollback foliation
                rowElement.ElementState = oldState;
                return true; 
            }
            return NextRight(); 
        } 

        internal override bool NextRight() { 
            // Make sure we do not get past the rowElement if we call NextRight on a just initialized iterator and rowElement has no children
            if ( currentNode == rowElement ) {
                currentNode = null;
                return false; 
            }
 
            ElementState oldState = rowElement.ElementState; 
            // We do not want to cause any foliation w/ this iterator or use this iterator once the region was defoliated
            Debug.Assert( oldState != ElementState.None ); 

            XmlNode nextNode = currentNode.NextSibling;

            if ( nextNode != null ) { 
                currentNode = nextNode;
                // If we have been defoliated, we should have stayed that way 
                Debug.Assert( (oldState == ElementState.Defoliated) ? (rowElement.ElementState == ElementState.Defoliated) : true ); 
                // Rollback foliation
                rowElement.ElementState = oldState; 
                return true;
            }

            // No next sibling, try the first sibling of from the parent chain 
            nextNode = currentNode;
            while ( nextNode != rowElement && nextNode.NextSibling == null ) 
                nextNode = nextNode.ParentNode; 

            if ( nextNode == rowElement ) { 
                currentNode = null;
                // If we have been defoliated, we should have stayed that way
                Debug.Assert( (oldState == ElementState.Defoliated) ? (rowElement.ElementState == ElementState.Defoliated) : true );
                // Rollback foliation 
                rowElement.ElementState = oldState;
                return false; 
            } 

            currentNode = nextNode.NextSibling; 
            Debug.Assert( currentNode != null );
            // If we have been defoliated, we should have stayed that way
            Debug.Assert( (oldState == ElementState.Defoliated) ? (rowElement.ElementState == ElementState.Defoliated) : true );
            // Rollback foliation 
            rowElement.ElementState = oldState;
            return true; 
        } 

        // Get the initial text value for the current node. You should be positioned on the node (element) for 
        // which to get the initial text value, not on the text node.
        internal bool NextInitialTextLikeNodes( out String value ) {
            Debug.Assert( this.CurrentNode != null );
            Debug.Assert( this.CurrentNode.NodeType == XmlNodeType.Element ); 
#if DEBUG
            // It's not OK to try to read the initial text value for sub-regions, because we do not know how to revert their initial state 
            if ( this.CurrentNode.NodeType == XmlNodeType.Element && mapper.GetTableSchemaForElement( (XmlElement)(this.CurrentNode) ) != null ) { 
                if ( this.CurrentNode != rowElement )
                    Debug.Assert( false ); 
            }
#endif

            ElementState oldState = rowElement.ElementState; 
            // We do not want to cause any foliation w/ this iterator or use this iterator once the region was defoliated
            Debug.Assert( oldState != ElementState.None ); 
 
            XmlNode n = this.CurrentNode.FirstChild;
            value = GetInitialTextFromNodes( ref n ); 
            if ( n == null ) {
                // If we have been defoliated, we should have stayed that way
                Debug.Assert( (oldState == ElementState.Defoliated) ? (rowElement.ElementState == ElementState.Defoliated) : true );
                // Rollback eventual foliation 
                rowElement.ElementState = oldState;
                return NextRight(); 
            } 
            Debug.Assert( ! XmlDataDocument.IsTextLikeNode( n ) );
            currentNode = n; 
            // If we have been defoliated, we should have stayed that way
            Debug.Assert( (oldState == ElementState.Defoliated) ? (rowElement.ElementState == ElementState.Defoliated) : true );
            // Rollback eventual foliation
            rowElement.ElementState = oldState; 
            return true;
        } 
 
        private static string GetInitialTextFromNodes( ref XmlNode n ) {
            string value = null; 

            if ( n != null ) {
                // don't consider whitespace
                while ( n.NodeType == XmlNodeType.Whitespace ) { 
                    n = n.NextSibling;
                    if ( n == null ) 
                        return String.Empty; 
                }
 
                if ( XmlDataDocument.IsTextLikeNode( n ) && (n.NextSibling == null || ! XmlDataDocument.IsTextLikeNode( n.NextSibling )) ) {
                    // don't use string builder if only one text node exists
                    value = n.Value;
                    n = n.NextSibling; 
                }
                else { 
                    StringBuilder sb = new StringBuilder(); 
                    while ( n != null && XmlDataDocument.IsTextLikeNode( n ) ) {
                        // Ignore non-significant whitespace nodes 
                        if ( n.NodeType != XmlNodeType.Whitespace )
                            sb.Append( n.Value );
                        n = n.NextSibling;
                    } 
                    value = sb.ToString();
                } 
            } 

            if ( value == null ) 
                value = String.Empty;

            return value;
        } 

 
 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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RegionIterator.cs source code in C# .NET

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