WhitespaceRuleReader.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / XmlUtils / System / Xml / Xsl / Runtime / WhitespaceRuleReader.cs / 1305376 / WhitespaceRuleReader.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
//-----------------------------------------------------------------------------
using System; 
using System.IO; 
using System.Xml;
using System.Xml.Schema; 
using System.Diagnostics;
using MS.Internal.Xml;

namespace System.Xml.Xsl.Runtime { 

    ///  
    ///  
    internal class WhitespaceRuleReader : XmlWrappingReader {
        private WhitespaceRuleLookup wsRules; 
        private BitStack stkStrip;
        private bool shouldStrip, preserveAdjacent;
        private string val;
        private XmlCharType xmlCharType = XmlCharType.Instance; 

        static public XmlReader CreateReader(XmlReader baseReader, WhitespaceRuleLookup wsRules) { 
            if (wsRules == null) { 
                return baseReader;    // There is no rules to process
            } 
            XmlReaderSettings readerSettings = baseReader.Settings;
            if (readerSettings != null) {
                if (readerSettings.IgnoreWhitespace) {
                    return baseReader;        // V2 XmlReader that strips all WS 
                }
            } else { 
                XmlTextReader txtReader = baseReader as XmlTextReader; 
                if (txtReader != null && txtReader.WhitespaceHandling == WhitespaceHandling.None) {
                    return baseReader;        // V1 XmlTextReader that strips all WS 
                }
                XmlTextReaderImpl txtReaderImpl = baseReader as XmlTextReaderImpl;
                if (txtReaderImpl != null && txtReaderImpl.WhitespaceHandling == WhitespaceHandling.None) {
                    return baseReader;        // XmlTextReaderImpl that strips all WS 
                }
            } 
            return new WhitespaceRuleReader(baseReader, wsRules); 
        }
 
        private WhitespaceRuleReader(XmlReader baseReader, WhitespaceRuleLookup wsRules) : base(baseReader) {
            Debug.Assert(wsRules != null);

            this.val = null; 
            this.stkStrip = new BitStack();
            this.shouldStrip = false; 
            this.preserveAdjacent = false; 

            this.wsRules = wsRules; 
            this.wsRules.Atomize(baseReader.NameTable);
        }

        ///  
        /// Override Value in order to possibly prepend extra whitespace.
        ///  
        public override string Value { 
            get { return (this.val == null) ? base.Value : this.val; }
        } 

        /// 
        /// Override Read in order to search for strippable whitespace, to concatenate adjacent text nodes, and to
        /// resolve entities. 
        /// 
        public override bool Read() { 
            XmlCharType xmlCharType = XmlCharType.Instance; 
            string ws = null;
 
            // Clear text value
            this.val = null;

            while (base.Read()) { 
                switch (base.NodeType) {
                case XmlNodeType.Element: 
                    // Push boolean indicating whether whitespace children of this element should be stripped 
                    if (!base.IsEmptyElement) {
                        this.stkStrip.PushBit(this.shouldStrip); 

                        // Strip if rules say we should and we're not within the scope of xml:space="preserve"
                        this.shouldStrip = wsRules.ShouldStripSpace(base.LocalName, base.NamespaceURI) && (base.XmlSpace != XmlSpace.Preserve);
                    } 
                    break;
 
                case XmlNodeType.EndElement: 
                    // Restore parent shouldStrip setting
                    this.shouldStrip = this.stkStrip.PopBit(); 
                    break;

                case XmlNodeType.Text:
                case XmlNodeType.CDATA: 
                    // If preserving adjacent text, don't perform any further checks
                    if (this.preserveAdjacent) 
                        return true; 

                    if (this.shouldStrip) { 
                        // Reader may report whitespace as Text or CDATA
                        if (xmlCharType.IsOnlyWhitespace(base.Value))
                            goto case XmlNodeType.Whitespace;
 
                        // If whitespace was cached, then prepend it to text or CDATA value
                        if (ws != null) 
                            this.val = string.Concat(ws, base.Value); 

                        // Preserve adjacent whitespace 
                        this.preserveAdjacent = true;
                        return true;
                    }
                    break; 

                case XmlNodeType.Whitespace: 
                case XmlNodeType.SignificantWhitespace: 
                    // If preserving adjacent text, don't perform any further checks
                    if (this.preserveAdjacent) 
                        return true;

                    if (this.shouldStrip) {
                        // Save whitespace until it can be determined whether it will be stripped 
                        if (ws == null)
                            ws = base.Value; 
                        else 
                            ws = string.Concat(ws, base.Value);
 
                        // Read next event
                        continue;
                    }
                    break; 
                case XmlNodeType.EndEntity:
                    // Read next event 
                    continue; 
                }
 
            // No longer preserve adjacent space
                this.preserveAdjacent = false;
                return true;
            } 

            return false; 
        } 
    }
} 

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

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