ChameleonKey.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 / Xml / System / Xml / schema / ChameleonKey.cs / 1305376 / ChameleonKey.cs
                        

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

    using System.Collections; 
    using System.ComponentModel;
    using System.Diagnostics;
    using System.Xml.Serialization;
 
    // Case insensitive file name key for use in a hashtable.
 
    internal class ChameleonKey { 
        internal string targetNS;
        internal Uri chameleonLocation; 
        // Original schema (used for reference equality only)
        //   stored only when the chameleonLocation is an empty URI in which case the location
        //   is not a good enough identification of the schema
        internal XmlSchema originalSchema; 
        int hashCode;
 
        ///  
        /// Creates a new chameleon key - an identification for a chameleon schema instance
        ///  
        /// The target namespace of the instance of the chameleon schema
        /// The original (chameleon) schema (the one without the target namespace).
        ///   This is used to get the location (base uri) and to identify the schema.
        public ChameleonKey(string ns, XmlSchema originalSchema) { 
            targetNS = ns;
            chameleonLocation = originalSchema.BaseUri; 
            if (chameleonLocation.OriginalString.Length == 0) { 
                // Only store the original schema when the location is empty URI
                //   by doing this we effectively allow multiple chameleon schemas for the same target namespace 
                //   and URI, but that only makes sense for empty URI (not specified)
                this.originalSchema = originalSchema;
            }
        } 

        public override int GetHashCode() { 
            if (hashCode == 0) { 
                hashCode = targetNS.GetHashCode() + chameleonLocation.GetHashCode() +
                    (originalSchema == null ? 0 : originalSchema.GetHashCode()); 
            }
            return hashCode;
        }
 
        public override bool Equals(object obj) {
            if (Ref.ReferenceEquals(this,obj)) { 
                return true; 
            }
            ChameleonKey cKey = obj as ChameleonKey; 
            if (cKey != null) {
                // We want to compare the target NS and the schema location.
                // If the location is empty (but only then) we also want to compare the original schema instance.
                // As noted above the originalSchema is null if the chameleonLocation is non-empty. As a result we 
                // can simply compare the reference to the original schema always (regardless of the schemalocation).
                Debug.Assert((chameleonLocation.OriginalString.Length == 0 && originalSchema != null) 
                    || (chameleonLocation.OriginalString.Length != 0 && originalSchema == null)); 
                return this.targetNS.Equals(cKey.targetNS) && this.chameleonLocation.Equals(cKey.chameleonLocation) &&
                    Ref.ReferenceEquals(originalSchema, cKey.originalSchema); 
            }
            return false;
        }
    } 
}

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

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