Helper.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Metadata / Helper.cs / 1305376 / Helper.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner       [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 
using System.Collections.Generic;
using System.Collections; 
using System.Linq;
using System.Diagnostics;
using System.Globalization;
using System.Reflection; 
using System.Text;
using System.Xml; 
using System.Xml.XPath; 
using System.Data.Mapping;
using System.IO; 
using System.Security;
using System.Security.Permissions;

 
namespace System.Data.Metadata.Edm
{ 
    ///  
    /// Helper Class for EDM Metadata - this class contains all the helper methods
    /// which only accesses public methods/properties. The other partial class contains all 
    /// helper methods which just uses internal methods/properties. The reason why we
    /// did this for allowing view gen to happen at compile time - all the helper
    /// methods that view gen or mapping uses are in this class. Rest of the
    /// methods are in this class 
    /// 
    internal static partial class Helper 
    { 
        #region Fields
        internal static readonly EdmMember[] EmptyArrayEdmProperty = new EdmMember[0]; 

        #endregion

        #region Methods 
        /// 
        /// The method wraps the GetAttribute method on XPathNavigator. 
        /// The problem with using the method directly is that the 
        /// Get Attribute method does not differentiate the absence of an attribute and
        /// having an attribute with Empty string value. In both cases the value returned is an empty string. 
        /// So in case of optional attributes, it becomes hard to distinguish the case whether the
        /// xml contains the attribute with empty string or doesn't contain the attribute
        /// This method will return null if the attribute is not present and otherwise will return the
        /// attribute value. 
        /// 
        ///  
        /// name of the attribute 
        /// 
        static internal string GetAttributeValue(XPathNavigator nav, 
                                                 string attributeName)
        {
            //Clone the navigator so that there wont be any sideeffects on the passed in Navigator
            nav = nav.Clone(); 
            string attributeValue = null;
            if (nav.MoveToAttribute(attributeName, string.Empty)) 
            { 
                attributeValue = nav.Value;
            } 
            return attributeValue;
        }

        ///  
        /// The method returns typed attribute value of the specified xml attribute.
        /// The method does not do any specific casting but uses the methods on XPathNavigator. 
        ///  
        /// 
        ///  
        /// 
        /// 
        internal static object GetTypedAttributeValue(XPathNavigator nav,
                                                     string attributeName, 
                                                     Type clrType)
        { 
            //Clone the navigator so that there wont be any sideeffects on the passed in Navigator 
            nav = nav.Clone();
            object attributeValue = null; 
            if (nav.MoveToAttribute(attributeName, string.Empty))
            {
                attributeValue = nav.ValueAs(clrType);
            } 
            return attributeValue;
        } 
 
        /// 
        /// Searches for Facet Description with the name specified. 
        /// 
        /// Collection of facet description
        /// name of the facet
        ///  
        internal static FacetDescription GetFacet(IEnumerable facetCollection, string facetName)
        { 
            foreach (FacetDescription facetDescription in facetCollection) 
            {
                if (facetDescription.FacetName == facetName) 
                {
                    return facetDescription;
                }
            } 

            return null; 
        } 

        // requires: firstType is not null 
        // effects: Returns true iff firstType is assignable from secondType
        internal static bool IsAssignableFrom(EdmType firstType, EdmType secondType)
        {
            Debug.Assert(firstType != null, "firstType should not be not null"); 
            if (secondType == null)
            { 
                return false; 
            }
            return firstType.Equals(secondType) || IsSubtypeOf(secondType, firstType); 
        }

        // requires: firstType is not null
        // effects: if otherType is among the base types, return true, 
        // otherwise returns false.
        // when othertype is same as the current type, return false. 
        internal static bool IsSubtypeOf(EdmType firstType, EdmType secondType) 
        {
            Debug.Assert(firstType != null, "firstType should not be not null"); 
            if (secondType == null)
            {
                return false;
            } 

            // walk up my type hierarchy list 
            for (EdmType t = firstType.BaseType; t != null; t = t.BaseType) 
            {
                if (t == secondType) 
                    return true;
            }
            return false;
        } 

        internal static IList GetAllStructuralMembers(EdmType edmType) 
        { 
            switch (edmType.BuiltInTypeKind)
            { 
                case BuiltInTypeKind.AssociationType:
                    return ((AssociationType)edmType).AssociationEndMembers;
                case BuiltInTypeKind.ComplexType:
                    return ((ComplexType)edmType).Properties; 
                case BuiltInTypeKind.EntityType:
                    return ((EntityType)edmType).Properties; 
                case BuiltInTypeKind.RowType: 
                    return ((RowType)edmType).Properties;
                default: 
                    return EmptyArrayEdmProperty;
            }
        }
 
        internal static AssociationEndMember GetEndThatShouldBeMappedToKey(AssociationType associationType)
        { 
            //For 1:* and 1:0..1 associations, the end other than 1 i.e. either * or 0..1 ends need to be 
            //mapped to key columns
            if (associationType.AssociationEndMembers.Any( it => 
                it.RelationshipMultiplicity.Equals(RelationshipMultiplicity.One)))
            {
                {
                    return associationType.AssociationEndMembers.SingleOrDefault(it => 
                        ((it.RelationshipMultiplicity.Equals(RelationshipMultiplicity.Many))
                         || (it.RelationshipMultiplicity.Equals(RelationshipMultiplicity.ZeroOrOne)))); 
                } 
            }
            //For 0..1:* associations, * end must be mapped to key. 
            else if (associationType.AssociationEndMembers.Any(it =>
                (it.RelationshipMultiplicity.Equals(RelationshipMultiplicity.ZeroOrOne))))
            {
                { 
                    return associationType.AssociationEndMembers.SingleOrDefault(it =>
                        ((it.RelationshipMultiplicity.Equals(RelationshipMultiplicity.Many)))); 
                } 
            }
            return null; 
        }

        /// 
        /// Creates a single comma delimited string given a list of strings 
        /// 
        ///  
        ///  
        internal static String GetCommaDelimitedString(IEnumerable stringList)
        { 
            Debug.Assert(stringList != null , "Expecting a non null list");
            StringBuilder sb = new StringBuilder();
            bool first = true;
            foreach (string part in stringList) 
            {
                if (!first) 
                { 
                    sb.Append(", ");
                } 
                else
                {
                    first = false;
                } 

                sb.Append(part); 
            } 
            return sb.ToString();
        } 


        // effects: concatenates all given enumerations
        internal static IEnumerable Concat(params IEnumerable[] sources) 
        {
            foreach (IEnumerable source in sources) 
            { 
                if (null != source)
                { 
                    foreach (T element in source)
                    {
                        yield return element;
                    } 
                }
            } 
        } 

        internal static void DisposeXmlReaders(IEnumerable xmlReaders) 
        {
            Debug.Assert(xmlReaders != null);

            foreach (XmlReader xmlReader in xmlReaders) 
            {
                ((IDisposable)xmlReader).Dispose(); 
            } 
        }
 
        #region IsXXXType Methods
        internal static bool IsStructuralType(EdmType type)
        {
            return (IsComplexType(type) || IsEntityType(type) || IsRelationshipType(type) || IsRowType(type)); 
        }
 
        internal static bool IsCollectionType(GlobalItem item) 
        {
            return (BuiltInTypeKind.CollectionType == item.BuiltInTypeKind); 
        }

        internal static bool IsEntityType(EdmType type)
        { 
            return (BuiltInTypeKind.EntityType == type.BuiltInTypeKind);
        } 
 
        internal static bool IsComplexType(EdmType type)
        { 
            return (BuiltInTypeKind.ComplexType == type.BuiltInTypeKind);
        }

        internal static bool IsPrimitiveType(EdmType type) 
        {
            return (BuiltInTypeKind.PrimitiveType == type.BuiltInTypeKind); 
        } 

        internal static bool IsRefType(GlobalItem item) 
        {
            return (BuiltInTypeKind.RefType == item.BuiltInTypeKind);
        }
 
        internal static bool IsRowType(GlobalItem item)
        { 
            return (BuiltInTypeKind.RowType == item.BuiltInTypeKind); 
        }
 
        internal static bool IsAssociationType(EdmType type)
        {
            return (BuiltInTypeKind.AssociationType == type.BuiltInTypeKind);
        } 

        internal static bool IsRelationshipType(EdmType type) 
        { 
            return (BuiltInTypeKind.AssociationType == type.BuiltInTypeKind);
        } 

        internal static bool IsEdmProperty(EdmMember member)
        {
            return (BuiltInTypeKind.EdmProperty == member.BuiltInTypeKind); 
        }
 
        internal static bool IsRelationshipEndMember(EdmMember member) 
        {
            return (BuiltInTypeKind.AssociationEndMember == member.BuiltInTypeKind); 
        }

        internal static bool IsAssociationEndMember(EdmMember member)
        { 
            return (BuiltInTypeKind.AssociationEndMember == member.BuiltInTypeKind);
        } 
 
        internal static bool IsNavigationProperty(EdmMember member)
        { 
            return (BuiltInTypeKind.NavigationProperty == member.BuiltInTypeKind);
        }

        internal static bool IsEntityTypeBase(EdmType edmType) 
        {
            return Helper.IsEntityType(edmType) || 
                   Helper.IsRelationshipType(edmType); 
        }
 
        internal static bool IsTransientType(EdmType edmType)
        {
            return Helper.IsCollectionType(edmType) ||
                   Helper.IsRefType(edmType) || 
                   Helper.IsRowType(edmType);
        } 
 
        internal static bool IsEntitySet(EntitySetBase entitySetBase)
        { 
            return BuiltInTypeKind.EntitySet == entitySetBase.BuiltInTypeKind;
        }

        internal static bool IsRelationshipSet(EntitySetBase entitySetBase) 
        {
            return BuiltInTypeKind.AssociationSet == entitySetBase.BuiltInTypeKind; 
        } 

        internal static bool IsEntityContainer(GlobalItem item) 
        {
            return BuiltInTypeKind.EntityContainer == item.BuiltInTypeKind;
        }
 
        internal static bool IsEdmFunction(GlobalItem item)
        { 
            return BuiltInTypeKind.EdmFunction == item.BuiltInTypeKind; 
        }
 
        internal static string GetFileNameFromUri(Uri uri)
        {
            if ( uri == null )
                throw new ArgumentNullException("uri"); 
            if ( uri.IsFile )
                return uri.LocalPath; 
 
            if ( uri.IsAbsoluteUri )
                return uri.AbsolutePath; 

            throw new ArgumentException(System.Data.Entity.Strings.UnacceptableUri(uri),"uri");
        }
 
        internal static bool IsEnumType(EdmType edmType)
        { 
            return BuiltInTypeKind.EnumType == edmType.BuiltInTypeKind; 
        }
 
        internal static bool IsUnboundedFacetValue(Facet facet)
        {
            return object.ReferenceEquals(facet.Value, EdmConstants.UnboundedValue);
        } 

        #endregion /// IsXXXType region 
 
        /// Performance of Enum.ToString() is slow and we use this value in building Identity
        internal static string ToString(System.Data.ParameterDirection value) 
        {
            switch (value)
            {
                case ParameterDirection.Input: 
                    return "Input";
                case ParameterDirection.Output: 
                    return "Output"; 
                case ParameterDirection.InputOutput:
                    return "InputOutput"; 
                case ParameterDirection.ReturnValue:
                    return "ReturnValue";
                default:
                    Debug.Assert(false, "which ParameterDirection.ToString() is missing?"); 
                    return value.ToString();
            } 
        } 

        /// Performance of Enum.ToString() is slow and we use this value in building Identity 
        internal static string ToString(System.Data.Metadata.Edm.ParameterMode value)
        {
            switch (value)
            { 
                case ParameterMode.In:
                    return EdmConstants.In; 
                case ParameterMode.Out: 
                    return EdmConstants.Out;
                case ParameterMode.InOut: 
                    return EdmConstants.InOut;
                case ParameterMode.ReturnValue:
                    return "ReturnValue";
                default: 
                    Debug.Assert(false, "which ParameterMode.ToString() is missing?");
                    return value.ToString(); 
            } 
        }
 
        #endregion
    }
}

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

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