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using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq.Expressions;
using System.Reflection;
using System.Text;
using System.Linq;
using System.Data.Linq.Mapping;
using System.Data.Linq.Provider;
namespace System.Data.Linq.SqlClient {
/// <summary>
/// This class defines the rules for inheritance behaviors. The rules:
///
/// (1) The same field may not be mapped to different database columns.
/// The DistinguishedMemberName and AreSameMember methods describe what 'same' means between two MemberInfos.
/// (2) Discriminators held in fixed-length fields in the database don't need
/// to be manually padded in inheritance mapping [InheritanceMapping(Code='x')].
///
/// </summary>
static class InheritanceRules {
/// <summary>
/// Creates a name that is the same when the member should be considered 'same'
/// for the purposes of the inheritance feature.
/// </summary>
internal static object DistinguishedMemberName(MemberInfo mi) {
PropertyInfo pi = mi as PropertyInfo;
FieldInfo fi = mi as FieldInfo;
if (fi != null) {
// Human readable variant:
// return "fi:" + mi.Name + ":" + mi.DeclaringType;
return new MetaPosition(mi);
}
else if (pi != null) {
MethodInfo meth = null;
if (pi.CanRead) {
meth = pi.GetGetMethod();
}
if (meth == null && pi.CanWrite) {
meth = pi.GetSetMethod();
}
bool isVirtual = meth != null && meth.IsVirtual;
// Human readable variant:
// return "pi:" + mi.Name + ":" + (isVirtual ? "virtual" : mi.DeclaringType.ToString());
if (isVirtual) {
return mi.Name;
} else {
return new MetaPosition(mi);
}
}
else {
throw Error.ArgumentOutOfRange("mi");
}
}
/// <summary>
/// Compares two MemberInfos for 'same-ness'.
/// </summary>
internal static bool AreSameMember(MemberInfo mi1, MemberInfo mi2) {
return DistinguishedMemberName(mi1).Equals(DistinguishedMemberName(mi2));
}
/// <summary>
/// The representation of a inheritance code when mapped to a specific provider type.
/// </summary>
internal static object InheritanceCodeForClientCompare(object rawCode, System.Data.Linq.SqlClient.ProviderType providerType) {
// If its a fixed-size string type in the store then pad it with spaces so that
// comparing the string on the client agrees with the value returnd on the store.
if (providerType.IsFixedSize && rawCode.GetType()==typeof(string)) {
string s = (string) rawCode;
if (providerType.Size.HasValue && s.Length!=providerType.Size) {
s = s.PadRight(providerType.Size.Value).Substring(0,providerType.Size.Value);
}
return s;
}
return rawCode;
}
}
}
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