QilReplaceVisitor.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / XmlUtils / System / Xml / Xsl / QIL / QilReplaceVisitor.cs / 1305376 / QilReplaceVisitor.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
//-----------------------------------------------------------------------------
 
using System; 
using System.Collections;
using System.Collections.Generic; 
using System.Diagnostics;
using System.Xml.Xsl;

namespace System.Xml.Xsl.Qil { 

    ///  
    /// Base internal class for visitors that replace the graph as they visit it. 
    /// 
    internal abstract class QilReplaceVisitor : QilVisitor { 
        protected QilFactory f;

        public QilReplaceVisitor(QilFactory f) {
            this.f = f; 
        }
 
 
        //-----------------------------------------------
        // QilVisitor overrides 
        //-----------------------------------------------

        /// 
        /// Visit all children of "parent", replacing each child with a copy of each child. 
        /// 
        protected override QilNode VisitChildren(QilNode parent) { 
            XmlQueryType oldParentType = parent.XmlType; 
            bool recalcType = false;
 
            // Visit children
            for (int i = 0; i < parent.Count; i++) {
                QilNode oldChild = parent[i], newChild;
                XmlQueryType oldChildType = oldChild != null ? oldChild.XmlType : null; 

                // Visit child 
                if (IsReference(parent, i)) 
                    newChild = VisitReference(oldChild);
                else 
                    newChild = Visit(oldChild);

                // Only replace child and recalculate type if oldChild != newChild or oldChild.XmlType != newChild.XmlType
                if ((object) oldChild != (object) newChild || (newChild != null && (object) oldChildType != (object) newChild.XmlType)) { 
                    recalcType = true;
                    parent[i] = newChild; 
                } 
            }
 
            if (recalcType)
                RecalculateType(parent, oldParentType);

            return parent; 
        }
 
 
        //-----------------------------------------------
        // QilReplaceVisitor methods 
        //-----------------------------------------------

        /// 
        /// Once children have been replaced, the Xml type is recalculated. 
        /// 
        protected virtual void RecalculateType(QilNode node, XmlQueryType oldType) { 
            XmlQueryType newType; 

            newType = f.TypeChecker.Check(node); 

            // Note the use of AtMost to account for cases when folding of Error nodes in the graph cause
            // cardinality to be recalculated.
            // For example, (Sequence (TextCtor (Error "error")) (Int32 1)) => (Sequence (Error "error") (Int32 1)) 
            // In this case, cardinality has gone from More to One
            Debug.Assert(newType.IsSubtypeOf(XmlQueryTypeFactory.AtMost(oldType, oldType.Cardinality)), "Replace shouldn't relax original type"); 
 
            node.XmlType = newType;
        } 
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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