XmlNamespaceManager.cs source code in C# .NET

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Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Xml / System / Xml / XmlNamespaceManager.cs / 1 / XmlNamespaceManager.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
//-----------------------------------------------------------------------------
 
namespace System.Xml { 

    using System; 
    using System.IO;
    using System.Collections;
    using System.Diagnostics;
    using System.Collections.Generic; 

    public class XmlNamespaceManager : IXmlNamespaceResolver, IEnumerable { 
        static IXmlNamespaceResolver s_EmptyResolver; 

        struct NamespaceDeclaration { 
            public string prefix;
            public string uri;
            public int    scopeId;
            public int    previousNsIndex; 

            public void Set( string prefix, string uri, int scopeId, int previousNsIndex ) { 
                this.prefix = prefix; 
                this.uri = uri;
                this.scopeId = scopeId; 
                this.previousNsIndex = previousNsIndex;
            }
        }
 
        // array with namespace declarations
        NamespaceDeclaration[] nsdecls; 
 
        // index of last declaration
        int lastDecl = 0; 

        // name table
        XmlNameTable nameTable;
 
        // ID (depth) of the current scope
        int scopeId; 
 
        // hash table for faster lookup when there is lots of namespaces
        Dictionary hashTable; 
        bool useHashtable;

        // atomized prefixes for "xml" and "xmlns"
        string xml; 
        string xmlNs;
 
        // Constants 
        const int MinDeclsCountForHashtable = 16;
 
        internal static IXmlNamespaceResolver EmptyResolver {
            get {
                if ( s_EmptyResolver == null ) {
                    // no locking; the empty resolver is immutable so it's not a problem that it may get initialized more than once 
                    s_EmptyResolver = new XmlNamespaceManager( new NameTable() );
                } 
                return s_EmptyResolver; 
            }
        } 

        internal XmlNamespaceManager() {
        }
 
        public XmlNamespaceManager( XmlNameTable nameTable ) {
            this.nameTable = nameTable; 
            xml = nameTable.Add("xml"); 
            xmlNs = nameTable.Add("xmlns");
 
            nsdecls = new NamespaceDeclaration[8];
            string emptyStr = nameTable.Add( string.Empty );
            nsdecls[0].Set( emptyStr, emptyStr, -1, -1 );
            nsdecls[1].Set( xmlNs, nameTable.Add( XmlReservedNs.NsXmlNs ), -1, -1 ); 
            nsdecls[2].Set( xml, nameTable.Add( XmlReservedNs.NsXml ), 0, -1 );
            lastDecl = 2; 
            scopeId = 1; 
        }
 
        public virtual XmlNameTable NameTable {
            get {
                return nameTable;
            } 
        }
 
        public virtual string DefaultNamespace { 
            get {
                string defaultNs = LookupNamespace( string.Empty ); 
                return ( defaultNs == null ) ? string.Empty : defaultNs;
            }
        }
 
        public virtual void PushScope() {
            scopeId++; 
        } 

        public virtual bool PopScope() { 
            int decl = lastDecl;
            if ( scopeId == 1 ) {
                return false;
            } 
            while( nsdecls[decl].scopeId == scopeId ) {
                if ( useHashtable ) { 
                    hashTable[nsdecls[decl].prefix] = nsdecls[decl].previousNsIndex; 
                }
                decl--; 
                Debug.Assert( decl >= 2 );
            }
            lastDecl = decl;
            scopeId--; 
            return true;
        } 
 
        public virtual void AddNamespace( string prefix, string uri ) {
            if ( uri == null ) 
                throw new ArgumentNullException( "uri" );

            if ( prefix == null )
                throw new ArgumentNullException( "prefix" ); 

            prefix = nameTable.Add( prefix ); 
            uri = nameTable.Add( uri ); 

            if ( ( Ref.Equal( xml, prefix ) && !uri.Equals( XmlReservedNs.NsXml ) ) ) { 
                throw new ArgumentException( Res.GetString( Res.Xml_XmlPrefix ) );
            }
            if ( Ref.Equal( xmlNs, prefix ) ) {
                throw new ArgumentException( Res.GetString( Res.Xml_XmlnsPrefix ) ); 
            }
 
            int declIndex = LookupNamespaceDecl( prefix ); 
            int previousDeclIndex = -1;
            if ( declIndex != -1 ) { 
                if ( nsdecls[declIndex].scopeId == scopeId ) {
                    // redefine if in the same scope
                    nsdecls[declIndex].uri = uri;
                    return; 
                }
                else { 
                    // othewise link 
                    previousDeclIndex = declIndex;
                } 
            }

            // set new namespace declaration
            if ( lastDecl == nsdecls.Length - 1 ) { 
                NamespaceDeclaration[] newNsdecls = new NamespaceDeclaration[nsdecls.Length * 2];
                Array.Copy( nsdecls, 0, newNsdecls, 0, nsdecls.Length ); 
                nsdecls = newNsdecls; 
            }
 
            nsdecls[++lastDecl].Set( prefix, uri, scopeId, previousDeclIndex );

            // add to hashTable
            if ( useHashtable ) { 
                hashTable[prefix] = lastDecl;
            } 
            // or create a new hashTable if the threashold has been reached 
            else if ( lastDecl >= MinDeclsCountForHashtable ) {
                // add all to hash table 
                Debug.Assert( hashTable == null );
                hashTable = new Dictionary( lastDecl );
                for ( int i = 0; i <= lastDecl; i++ ) {
                    hashTable[nsdecls[i].prefix] = i; 
                }
                useHashtable = true; 
            } 
        }
 
        public virtual void RemoveNamespace( string prefix, string uri ) {
            if ( uri == null ) {
                throw new ArgumentNullException( "uri" );
            } 
            if ( prefix == null ) {
                throw new ArgumentNullException( "prefix" ); 
            } 

            int declIndex = LookupNamespaceDecl( prefix ); 
            while ( declIndex != -1 ) {
                if ( String.Equals( nsdecls[declIndex].uri, uri ) && nsdecls[declIndex].scopeId == scopeId ) {
                    nsdecls[declIndex].uri = null;
                } 
                declIndex = nsdecls[declIndex].previousNsIndex;
            } 
        } 

        public virtual IEnumerator GetEnumerator() { 
            Hashtable prefixes = new Hashtable( lastDecl + 1 );
            for( int thisDecl = 0; thisDecl <= lastDecl; thisDecl ++ ) {
                if ( nsdecls[thisDecl].uri != null ) {
                    prefixes[nsdecls[thisDecl].prefix] = nsdecls[thisDecl].prefix; 
                }
            } 
            return prefixes.Keys.GetEnumerator(); 
        }
 
// This pragma disables a warning that the return type is not CLS-compliant, but generics are part of CLS in Whidbey.
#pragma warning disable 3002
        public virtual IDictionary GetNamespacesInScope( XmlNamespaceScope scope ) {
#pragma warning restore 3002 
            int i = 0;
            switch ( scope ) { 
                case XmlNamespaceScope.All: 
                    i = 2;
                    break; 
                case XmlNamespaceScope.ExcludeXml:
                    i = 3;
                    break;
                case XmlNamespaceScope.Local: 
                    i = lastDecl;
                    while ( nsdecls[i].scopeId == scopeId ) { 
                        i--; 
                        Debug.Assert( i >= 2 );
                    } 
                    i++;
                    break;
            }
 
            Dictionary dict = new Dictionary( lastDecl - i + 1 );
            for( ; i <= lastDecl; i++ ) { 
                string prefix = nsdecls[i].prefix; 
                string uri = nsdecls[i].uri;
                Debug.Assert( prefix != null ); 

                if ( uri != null ) {
                    if ( uri.Length > 0 || prefix.Length > 0 || scope == XmlNamespaceScope.Local ) {
                        dict[prefix] = uri; 
                    }
                    else { 
                        // default namespace redeclared to "" -> remove from list for all scopes other than local 
                        dict.Remove( prefix );
                    } 
                }
            }
            return dict;
        } 

        public virtual string LookupNamespace( string prefix ) { 
            int declIndex = LookupNamespaceDecl( prefix ); 
            return ( declIndex == -1  ) ? null : nsdecls[declIndex].uri;
        } 

        private int LookupNamespaceDecl( string prefix ) {
            if ( useHashtable ) {
                int declIndex; 
                if ( hashTable.TryGetValue( prefix, out declIndex ) ) {
                    while ( declIndex != -1 && nsdecls[declIndex].uri == null ) { 
                        declIndex = nsdecls[declIndex].previousNsIndex; 
                    }
                    return declIndex; 
                }
                return -1;
            }
            else { 
                // First assume that prefix is atomized
                for( int thisDecl = lastDecl; thisDecl >= 0; thisDecl -- ) { 
                    if ( (object)nsdecls[thisDecl].prefix == (object)prefix && nsdecls[thisDecl].uri != null ) { 
                        return thisDecl;
                    } 
                }

                // Non-atomized lookup
                for( int thisDecl = lastDecl; thisDecl >= 0; thisDecl -- ) { 
                    if ( String.Equals( nsdecls[thisDecl].prefix, prefix ) && nsdecls[thisDecl].uri != null ) {
                        return thisDecl; 
                    } 
                }
            } 
            return -1;
        }

        public virtual string LookupPrefix( string uri ) { 
            // Don't assume that prefix is atomized
            for( int thisDecl = lastDecl; thisDecl >= 0; thisDecl -- ) { 
                if ( String.Equals( nsdecls[thisDecl].uri, uri ) ) { 
                    string prefix = nsdecls[thisDecl].prefix;
                    if ( String.Equals( LookupNamespace( prefix ), uri ) ) { 
                        return prefix;
                    }
                }
            } 
            return null;
        } 
 
        public virtual bool HasNamespace( string prefix ) {
            // Don't assume that prefix is atomized 
            for( int thisDecl = lastDecl; nsdecls[thisDecl].scopeId == scopeId; thisDecl-- ) {
                if ( String.Equals( nsdecls[thisDecl].prefix, prefix ) && nsdecls[thisDecl].uri != null ) {
                    if ( prefix.Length > 0 || nsdecls[thisDecl].uri.Length > 0 ) {
                        return true; 
                    }
                    return false; 
                } 
            }
            return false; 
        }

        internal bool GetNamespaceDeclaration( int idx, out string prefix, out string uri ) {
            idx = lastDecl - idx; 
            if ( idx < 0 ) {
                prefix = uri = null; 
                return false; 
            }
 
            prefix = nsdecls[idx].prefix;
            uri = nsdecls[idx].uri;

            return true; 
        }
   } //XmlNamespaceManager 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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